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DRAINS User Manual

1. Constant Time mina Flow path length m Flow path slope Flow path roughness Figure 2 20 Rational Method Sub Catchment Property Sheet DRAINS User Manual 2 14 November 2014 The sheet is similar for the three available types of rational method model General Australian Rainfall and Runoff 1987 and Standards Australia AS NZS 3500 3 2003 The only difference is the need to enter roofed percentages for the AS NZS 3500 3 method If a DRAINS model is converted to a rational method model the paved and supplementary area percentages will be added to form the impervious area percentage The impervious area constant time will be the paved area constant time and the pervious area constant time will be the grassed area constant time With the current version of DRAINS no adjustments are made for supplementary area times or for grassed area lag factors If allowance is to be made it will have to be done for each sub catchment individually c Extended Rational Method Sub Catchments The property sheet used is the same as that for the rational method as shown in Figure 2 20 d Storage Routing Model Sub Catchments The three storage routing model described in Section 5 4 RORB RAFTS and WBNM require different inputs due to their different structures and parameters Figure 2 21 shows a RORB sub catchment input Since no routing calculations occur in a RORB sub catchment in DRAINS only the sub catchment area and impervious area
2. Record 14 1 frl Show All Selected Records 0 out of 7 Selected Options Figure 3 53 Table of Pit Data Note that this includes results with the 2Yr added to headings as a suffix If another run is made and the process is repeated with one of the existing shapefiles nominated in the Save As dialog box additional DRAINS User Manual 3 32 November 2014 results will be appended as shown in Figure 3 54 and Figure 3 55 where 100 year ARI results are added to the 5 year ARI results If data from a GIS data base can be assembled into this same format less the results the File gt Import option ESRI Shapefiles can be used to import data into DRAINS Cc ustomise Gis Files Suffix for result fields inthe GIS 100rr Cancel C Create new files f Add results to existing files Mote Ifyou add results to existing files iti your responsibility to ensure that the existing GIS files are current ie pipes pits etc in the GIS are an exact match for those curently in DRAINS IF you are unsure you should choose create new files Figure 3 54 Naming of Second Set of Results wma S mo 3026 a mo 2034 as mo an an mo faa Jas mooo 226 Figure 3 55 Expanded Table of Pipe Data b Exporting MapInfo Files It is first necessary to establish a system that is capable of being run in DRAINS such as the demonstration example shown in Figure 3 49 Selecting the MapInfo files option from the File g
3. 1 Depression ii ne Time Time of Travel Storage mm or Time of Entry Figure 5 12 Calculation of Hydrographs from Paved and Supplementary Areas DRAINS User Manual 5 13 November 2014 HYETOGRAPH TIME AREA DIAGRAM HYDROGRAPH Intensit i ami Contributing Flowrate _Horton Infiltration Curve Area Na Full Area m s convolved Produces with P Time gt AG Time Time me oO Time Entry Subtract Subtract Horton Depression Infiltration mm h Storage mm Figure 5 13 Calculation of Hydrographs from Grassed Areas As explained earlier grassed area hydrographs can be delayed to allow for any time lag occurring when grassed area flows travels over paved surfaces to the pipe system All hydrographs in the program are linked to the same time base and are synchronised and combination of input hydrographs is a straightforward addition process As shown in Figure 5 14 the supplementary area hydrograph is incorporated in the grassed area hydrograph This is added to the paved area hydrograph and possible user provided hydrographs or baseflow to obtain the total runoff hydrograph coming off the local sub catchment Overflows from upstream pits if present are then added to this to obtain the total approach flow to a pit simple node or detention basin Rainfall Runoff from the Supplementary Area Infiltration Figure 5 14 Flows between Strips in Time Area Calculations At pits an
4. a Edit the files so that both include two adjacent pits with the same names Make sure that you have zoomed in to the model so that there is an observable distance between pits lf the model is ata low magnification so that individual pipes cannot be seen there may be round off errors in the process that DRAINS applies when creating a merge file This may lead to sub catchments and other components being connected wrongly b In the file to be added use the Export a Merge File option in the File menu to create and name a mrg merge file DRAINS User Manual 3 35 November 2014 c Then close the file to be added and open the file with the receiving system Using the Import a Merge File option in the File menu read in the mrg merge file created in Step b d The merged system will appear The orientation of pipes will be that of the receiving system You can then tidy this up save the combined file and make runs as required This process is demonstrated by opening the file shown as Toowoomba Addition drn in Figure 3 60 and creating a merge file named Toowoomba Addition mrg with the Export a Merge File option in the File menu This can then be imported into Toowoomba Estate drn displayed in Figure 3 23 using the Import a Merge File option in the File menu The joined system is shown in Figure 3 61 It is possible to join models together when these do not have common pits by drawing top dummy pits The process Is as foll
5. DRAINS User Manual 2 43 November 2014 o5 s hittpa reg bam goa hydra has ediriweto edirtwebu shiml Prbax Wekome to the IPD Program H H Eile dt Wow Fovertes Took Help Hoene Crease an FD About FCs Feedback l View input Help Regat input Navigate using mouse or Tab key and use RETURN SPACEBAR or mouse button to select Create an IFD 3 Enter coordinates of desired location Choose only one method 2 Degrees l Easting Northing Sone Deg Min Ser Easting Latit 35 13 l Latitude EP s oR tatituce E oop Northing Lorgitude BCR E cor E g zw Step D Submit Only accessible after accepting conditions in Step C smial rn ail Figure 2 67 Create an IFD Dialog Box Enter the latitude longitude and name of the site click the Conditions of Use box and press the Submit button to produce the following web page E IRT hitp awe bomgovaw hydro has odinmvebu cdirrwebsshiml P EPON E Welcome te the IAD Program 1 Tar w File Edt View Fproiites Tools Help Costicients Primi IFD chari Haig FO chant i eo 300 t i DESIGN RAINFALL INTENSITY CHART Pr 30 Leestion NEAR Maray Bridge 3A x 00 Coordinates 35 1255 135 273 issued POE 20 7 150 E ig wf 1 E i f fe t a 40 coe i 3 35 Pir Pr a 18 t L amp S 4 4 a a 4 AVERAGE RECURRENCE INTERVAL 3 100 Y arsiupp i tuie i 2 50 Years 20
6. Reach Length m 1020 Scale off Length Sede fe Natural C Excavated unlined Lined or Piped Channel condition CC Drowned C Natural 3 f j Excavated unlined Avg hama Sope el i Use Ke and m from Lined or Piped e Default Hydrological model C Drowned C You specify Notes Cmos e Figure 2 48 RORB Stream Routing Reach Property Sheet DRAINS User Manual 2 32 November 2014 Overflow Route Reach Basic Data Cross Section Data N hA Alow Routing in Basic and Standard Models ame Rea EN A Simple Translation no attenuation Kinematic Wave Travel Time mins 5 Figure 2 49 First Form of the RAFTS Stream Routing Reach Property Sheet Top Part If the second option in the Flow Routing Method box is chosen the property sheet changes to the form shown in Figure 2 50 It is now necessary to provide a reach length and using the second page of the property sheet shown in Figure 2 51 a cross section is to be selected from the Overflow Route Data Base This section is meant to be representative of the whole stream reach and to be used in a kinematic wave routing procedure derived from Chapter 9 of Open Channel Hydraulics by F M Henderson 1966 Overflow Reach amp ox Basic Data Cross Section Data ame d i 0 Kinematic Wave Reach Length m 1500 Scale off Length Figure 2 50 Second Form of the RAFTS Stream Routing Reach Property Sheet Top Part Overflow Route Reach A eo
7. 2 4 6 Pit Data Base The Pit Data Base is accessed through the Pit Data Base option in the Project menu As shown in Figure 2 78 pits are organised into types or families of different sizes in a similar way to pipes The pit type is described in the Pit Type property sheet also shown in Figure 2 78 Pit Data Base Pit Family MSW ATA SA Inlet 3 crosstall 1 grade HSW ATA 5A Inlet 3 crosstall 3 grade HSW ATA SA Inlet 3 crosstall 5 grade E P NSW ATA SA Inlet 3 crossfall 7 grade Alii NSW ATA SA Inlet 3 crosstall 934 grade NSW ATA SFI Median Inlet 3 crosstall 1 grade Froperties NSW ATA SFI Median Inlet 3 crosstall 34 grade NSW ATA SFI Median Inlet 3 crossfall 5 grade BIC OTA COA kdai na lalak Oe nrananank all TE nrn Fit Size or Description SAT Type 2 1 longitudinal grade Add 5A2 Type 5 1 longitudinal grade 5A5 Type 9 1 longitudinal grade Remove Properties NOTE Many of the pit inlet capacity relationships supplied with DRAINS have been obtained from published data and then extrapolated Itis the User s responsibility to ensure that the relationships are suitable for the pits being modelled Watercom and Or G O Loughlin accept no responsibility for the accuracy or suitability of these relationships OF Cancel Help Mame NSW ATA SA Inlet 3 crosstall 1 grade Cancel Figure 2 78 Main Pit Data Base Property Sheet and Pit Type Property Sheet Data for each individu
8. Overflow routes are the next components to be defined You must define a name and an estimated time of flow as shown in Figure 1 25 and you must also define overflow route cross sections from the overflow route data base with slopes and percentages of downstream sub catchments as shown in Figure 1 26 DRAINS User Manual 1 16 November 2014 Pipe from Pit 1 to Pit 2 Pipe name Pie Fipe length m Upstream invert elev m p Pipe Type Concrete under roads 1 minimum slope Downstream invert elev m Slope 72 Hom Diameter mm LD mm inai No of identical parallel pipes Include Non Return Valve Pipe Roughness During Design rune this pipe f is new diameter and level can change f is new but diameter and level are fined f You specify C js existing diameter and level are fixed f is new downstream invert level is fixed Cancel Survie Data Scale off Length Help Figure 1 24 The Pipe Property Sheet Page 1 Table 1 3 Pipe Data for Orange Example Name From To Length t Overflow Route OF Basic Data Cross Section Data Name OF 1 Travel Time mins 0 1 i Figure 1 25 The Overflow Route Property Sheet Page 1 Top Portion Note that Figure 1 25 may include additional data entry boxes if the storage routing or premium hydraulic model options are available Only the information shown above is required in the Orange example The overflow
9. As noted above the Queensland Urban Drainage Manual Queensland Department of Natural Resources and Water 2008 contains a procedure that guides a designer through a set of Missouri and Hare Charts enabling ku and if appropriate water level factor kw and branch pipe factor k to be determined This procedure has been outlined in Section 3 4 4 with the related spreadsheet outputs for rational method calculations being set out in Section 3 5 4 It involves a search through several graphs based on criteria set out in Appendix 4 in QUDM Volume 2 In complex cases where there is no appropriate chart an estimate from the momentum equations described by Hare and O Loughlin 1991 is used The procedure in DRAINS allows k coefficients to be determined automatically without consideration of all circumstances It is therefore important to carry out checks using the appropriate charts d Part Full Pipe Pressure Changes Information on part full pit pressure changes is sketchy because researchers have concentrated on the full pipe flow case that is more likely to occur at peak flows through pipe systems The treatment of part full pressure changes has varied in DRAINS as additional information has become available and the needs of the hydraulic modelling procedures have changed Currently in the standard and premium unsteady flow models a constant pit pressure change coefficient ku is assumed to apply to both full pipe and part full flows This
10. Cross Section Data Fow equation f Use weir equation C You specify H vs Q Weir Coefficient C 1 7 Crest Length E Crest Level 701 3 Figure 2 38 Outlet Definition of a Weir Top Portion of Page Overflow Route OF 7 mS Basic Data Weir Data Cross Section Data Fow equation C Use we nut water Dacre f You specify H vs Q uS 1 7028 0 2 703 1 0 22 3 43 4 0 35 4 703 7 0 46 5 703 8 0 90 6 703 9 1 30 7 74 219 E Faste Table Figure 2 39 Elevation Discharge Table for a High Level Outflow Top Portion For a weir you must provide a weir coefficient a width m at right angles to the direction of flow and a crest level m Further details are given in Section 5 8 2 A suitable coefficient for the earth embankments used as high level outlets for many detention basins is 1 7 If used alone the elevation discharge relationship must be determined using equations relating to both the low and high level outlets If it is certain that no backwater effect can submerge the outlets this relationship will be constant As noted earlier if None is specified for the low level outlet in the Detention Basin property sheet and an elevation discharge relationship is given in the Overflow Route property sheet a simplified basin routing can be applied DRAINS User Manual 2 26 November 2014 There can be any number of overflow routes from a basin representing high level outlets at various levels Pumped disc
11. DRAINS The following pits could not be satisfactorily sized Pit 6 6 Pit C1 You could try one or more of the following a adding larger pits e g double pits to the pit data base b increasing the size of upstream pit s and marking them Existing cannot be designed c relocating pits d providing additional pits Figure 4 9 Warning of Failure to Define a Feasible Design The results can be checked by Analysis runs to ensure that the design conditions are met By taking full advantage of allowable surface flow capacities the sizes and costs of pipe systems can be minimised 4 3 Applying DRAINS 4 3 1 Integration A key feature of DRAINS is integration This occurs internally with the data inputs hydrology hydraulics and presentation of results operating in the same package and the ability to model different parts and scales of stormwater systems together It also occurs externally with the linkages to other programs shown in Figure 4 10 Data Base CAD Files TA CAD and DTM GIS Programs Access Files Programs Figure 4 10 Integrated Linkages between DRAINS and other programs The general operation of DRAINS have been illustrated in Chapter 1 This section provides guidance on applications to specific types of stormwater drainage system 4 3 2 Designing Subdivision Piped Drainage Systems Design runs are mainly made for new systems on greenfields sites where the developer and designer have considera
12. Since Q is not Known exactly when the tailwater level is being established an iterative procedure must be used In the above equations ke is the entrance loss factor k is the total of other loss factors e g at bends and Factor is a friction factor If Manning s Equation is used with a roughness n it is 2 D 43 n L 2g 1 Equation 5 4 DRAINS User Manual 5 39 November 2014 If the Colebrook White Equation is used the Factor is f z where f is the Darcy Weisbach friction factor This can be obtained using an initial value given by the Swamee Jain equation f 1 325 loge k 3700 D 5 74 N Equation 5 35 and iterations using the Colebrook White Equation f 1 325 loge k 3700 D 2 51 Nef _ Equation 5 5 In which k is the Colebrook White wall roughness height mm Nr is the Reynolds Number of the flow This is unknown when calculations are performed but it can be estimated roughly as VD Qo OD DoD TU 2 4 D V is the velocity of flow m s and v is the kinematic viscosity of water 1 14 x 10 m s at 15 C Note that the flowrate is assumed to be to be the inlet flow estimate and the pipe is assumed to be flowing full This is not exact and an iterative procedure should be used However the value of f is insensitive to the Nr used and this approximation should be adequate Equation 5 37 V Outlets with Rectangular Cross Sections These are based on the thresho
13. Table A 13 Pipe System Hydraulic Models Estimation of velocities and flow capacities for pipe full Manual calculations using Manning s but not under pressure conditions equation or a similar relationship Normal depth calculations estimating flow depths Manual or spreadsheet calculations or velocities and other characteristics for a given flowrate simple overflow route calculations in involving simple iterative procedures programs such as DRAINS Projection of hydraulic grade lines through pipe DRAINS basic hydraulics model now systems allowing for full and part full flow pipe obsolete friction and pit pressure losses 1 D unsteady water surface profile calculations DRAINS SWMM xpswmm Mouse through pipes using Priessmann slot or similar methods to model full pipe flows The basic hydraulics procedure was the first model implemented in DRAINS It is now obsolete and only available in models developed with pre 2011 versions of DRAINS The current standard and premium hydraulic models both apply unsteady flow hydraulic calculations in pipes and channels They differ in the hydraulic calculations for overflow routes The standard model assumes uniform flows providing information based on normal depth calculations for the peak calculated flows at a nominated point along DRAINS User Manual A 19 November 2014 the overflow route The premium model calculates a full water surface profile along overflow routes allowing for tail
14. a Colebrook White or Manning s roughness coefficient New or NewFixed or Existing the number of parallel pipes usually 1 In a shapefile exported from DRAINS there may also be Flow_XXXXX__ optionally one or more flowrates from different storms designated by XXXXX V_XXXXX optionally one or more velocities from different storms for example SOYr For information on the other four components you can refer to the formats of exported ESRI files in the MIF files Note that all numbers are exported as text and not as numbers They will need to be converted in an ESRI program if the attributes are to be used as the basis for colour coded thematic mapping c MapInfo Formats Maplnfo stores spatial information in a set of two ASCII files both having the same initial part of their name e aMIF MapInfo Interchange File is the main file defining a format for data records associated with objects points lines or polygons and the coordinates of the vertices of objects e a MID file containing the contents of a table of attributes associated with each object The data for nodes pits in the MID file is in a table with the following 12 headers DRAINS User Manual 5 45 November 2014 any name up to 11 characters 2 DRAINSid an internal number used by DRAINS to connect nodes and links this must be kept blank type of node OnGrade Sag or Node 4 Family the pit family corresponding to a family in t
15. 060 E I I o o Al AIO NO N _ O AINIO O _ Greek 2 3 81 32 14 8 12 0 0 27 Strathfield 31 10 81 53 17 7 12 5 0 60 j zeyaney 14 12 81 38 6 0 5 3 0 37 18 1 82 6 2 3 2 7 0 32 24 3 82 45 22 4 16 0 0 38 Cs Berowra 9 11 80 31 0 6 0 7 0 18 Sydney 29 12 80 38 1 1 1 2 0 11 7 1 81 22 0 5 0 3 0 19 24 1 81 14 0 3 0 3 0 18 7 11 81 10 1 5 0 7 0 15 15 11 81 8 0 9 0 8 0 21 21 11 81 47 0 7 0 7 0 25 19 12 81 16 1 1 0 8 0 07 Table 5 8 SWMM and ILSAX Results for Bunnerong Catchment Maroubra Sydney Vale Attwater and O Loughlin 1986 Storm AMC me a ved ved 1377 4 405 168 144 1 02 203 17 2 878 53 77 4 123 096 119 055 549 487 198 18 3 78 2 60 2 314 3 08 156 30 0 252 119 18 19 3 78 4 144 139 1 75 090 658 593 3 23 19 20 6 79 2 496 241 220 1 37 239 207 803 20 21 6 79 4 205 130 146 057 952 836 261 17 3 83 4 36 0 446 466 211 2214 27 0 5 25 5 11 84 2 169 1 469 458 181 943 95 0 254 6 11 84 4 447 026 040 031 1 21 1 50 0 75 67 11 84 4 170 056 060 036 680 689 3 06 89 11 84 4 893 333 421 170 546 586 143 Table 5 9 and Figure 5 15 present more recent comparisons between ILSAX DRAINS and observed data for 25 storms recorded at the University of Technology Sydney gauging station at Hewitt Penrith This
16. General H ay B a Insert 7 3 Delete E kad Merge amp Center s h 9 68 rx Conditional Format Cell ee JE Sot amp Find amp Alignment F Number F Formatting 7 as Table Styles 7 Hed Format lt 27 Filtery Select Styles Cells Editing Nerang Gilston Road Daily 5 Day Month Day Depth Preceeding mm Depth mm 5 1 n a 0 n a 0 n a 0 0 COON ON FWHM n a E n a 0 8 51 122 08 05 13 13 5 13 5 OOaAN DMF WMH 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 4 4 4 x DRAINS User Manual 040160 Nerang Gilston Road Ranked Rank Year WOON DMF WHM 1931 1887 2005 1953 1956 1892 1976 1974 1948 1908 1947 1943 1919 1967 1892 1974 1953 1887 1954 1921 1947 1965 1910 1987 1903 Month Day a bh Aee MWNHYNNYNN DWH FWHM AH BWA NYVANMNM N MY 6 13 30 17 18 15 11 26 15 14 25 17 29 12 13 22 23 13 22 23 13 19 12 5 31 Daily 5 Day Mean AMC 3 52 Depth Preceeding AMC Mean 5 Day Rainfall 98 98 mm mm Depth mm 401 3 349 5 346 341 4 334 5 SERI 313 302 288 8 278 1 276 9 262 6 259 1 254 249 7 249 238 3 237 2 228 9 226 1 226 1 215 1 210 3 208 281 7 7 1 97 6 51 8 3 8 67 8 18 2 109 7 43 5 0 243 3 43 7 NwrFPNHOHFHE HE NMA HFFA HHA HE WENFHHNM SF Median 5 Day Rainfall 63 65 mm Bin Frequency 3 AMC Values November 2
17. HGL 7066005 oe 706 568 706 406 M 706 046 TAE aad TOS Ft 705 655 7065 T0G 1 Suinaine Level hert Level 706050 707 1 705932 7058902 7070 705 30 TNE ITE 705 008 704930 enh aan 703552 17750 703522 7053 703015 20720 702 985 7045 703349 T02 300 702 735 Chainage 15 80 7550 BF A0 166 50 Save as DMF Pririt Customise Close Help Figure 3 39 Preview of Long Section Plot Once a satisfactory layout is achieved clicking the Save as DXF button opens a window in which the file name and location can be specified This creates the DXF file which can then be viewed and manipulated in a CAD program as shown in Figure 3 41 and printed from this aoe Customise Long Section Drawin Aspect Ratio 20 Horizontal to 1 Vertical Datum Elevation Au starting Chainage m 0 Line width multipliers Text size multiplier 1 W Show HGL and Flow Fit lines 1 Pipe lines 1 Other lines 1 Cancel Help Figure 3 40 Dialog Box for Customising a Long Section 3 5 4 Spreadsheet Outputs and Inputs The spreadsheet option provides a convenient way to view and store data and results as well as a medium for transferring information between DRAINS and other programs It effectively supersedes the text file output described in the previous section although this is retained for the convenience of users To exchange information with a spreadsheet program say Excel both programs
18. Runoff Volumes 28 AR amp R 2ye 125 79 65 70 52 1 65 24 86 0 46 0 9 29 A0 PIPE DETAILS 7 A M 4 gt h Data Minor lt Major_ 3 Mh Ready m Figure 1 34 Spreadsheet Output for Minor Storm Results 3 Orange2 DRAINS Lo Ss ll CT ae eee File Edit Project View Draw Run Help 3 Pipe 3 Hydrograph AR amp R 100 year 25 minutes storm average 101 mm h Zone 2 f a 8 Ala m vw uu Ss als File Edit Properties AR amp A 100 year 25 minutes storm average 101 mm v 01 0 09 0 08 v 0 07 E 0 06 3 0 05 v 0 04 0 03 z 0 02 E 0 01 0 0 20 40 60 80 100 Time mins aN 0 097 0 010 l 0 174 a Fa N i 3 Pit 3 HGL AR amp R 100 year 25 minutes storm average 101 mm h Zone 2 lale x 0 File Edit Properties Bi eee Se poses eee open ence epee epegeeeuseeee eee Surface Level 21 9 LN SORTS EPCS ETATE STO Freeboard Limit 21 8 21 7 21 6 E 21 5 E 214 Outlet Obvert Level 21 3 0 20 40 60 80 100 120 A Time mins Results of Standard Hydraulic Analysis Figure 1 35 Analysis Run Results for a Major Storm a Saving Data and Results This last step involves the storage of results The input data is all stored in the DRAINS data file Orange2 drn There is plenty of opportunity to make comments in the spaces provided in the property sheets for individual components and in a Description
19. and other comparisons with data recorded at Penrith Pereira 1998 Tran 1998 have shown that ILSAX and DRAINS produce similar hydrographs at catchment outlets except in large storms where backwater effects influence the pipe system hydraulics j gt N 18 3 78 AIAINI AI AINIS K Table 5 9 Comparisons between ILSAX and DRAINS Calculated Flows and Observed Flows at the Hewitt Gauging Station Penrith Sydney O Loughlin Stack and Wilkinson 1998 Shek and Lao 1998 Chan 1998 Peak Flowrate m s Runoff Volume m Date ILSAX DRAINS ILSAX DRAINS 23 1 92 5452 4540 23 2 92 2251 2162 21 12 92 3368 2920 DRAINS User Manual 5 15 November 2014 1140 1547 593 1160 1042 3 6 3018 3158 14885 11683 1046 858 2206 2366 586 405 1377 1080 30 3 94a_ 3 6 164 099 162 1335 1310 1263 824 DRAINS User Manual 5 16 November 2014 5 3 4 Rational Method Procedures DRAINS offers three options for the rational method which can be mixed together in a single system If your version of DRAINS is enabled to run the rational method it is chosen by selecting a rational method model as a default in the Hydrological Model Specifications dialog box opened from the Project menu The first option available in the Rational Method Model property sheet that is called from the Hydrological Model Specifications box is a general rational method procedure It is necessary to specify four runoff coefficients an imperv
20. catchment outlet calculated by dividing the sum of catchment areas multiplied by their distances from the outlet by the total catchment area X A d A and Q is flowrate m s k acts as a Calibration parameter enabling the model s results to be varied and fitted to recorded hydrographs A k of 0 0 will perform no routing so that values of rainfall excess and flows from upstream storages will pass through a sub catchment unchanged A k that is very large will delay flows considerably so that flowrates will be very low By adjusting k the peak of a calculated hydrograph can be varied over the range from the peak rate of rainfall excess to zero Decreasing k increases flowrates Allowance is made for different channel conditions by multiplying the routing factors by the values in Table 5 11 in which S is the reach slope Table 5 11 Reach Adjustment Factors in RORB Model Excavated and unlined 11 3S8 Lined or piped 1 9S Drowned by a reservoir a The routing through a sub catchment in a RORB model will depend on the length of the stream channel through the sub catchment and the average distance to the outlet l When combining a RORB model with an ILSAX model the lengths of channels and pipes in the ILSAX model will be used to calculate Ic If ak value from a stand alone RORB model is used in this case it will result in an incorrect routing calculation It will be necessary to use a different k that can
21. one applied in the U S The hydraulic procedures are the same as those used in all English speaking countries using Colebrook White and Manning s equations 1 1 3 Computer Aspects DRAINS follows Microsoft Windows conventions and runs on all version of the Windows operating system from Windows 95 to Windows 7 PC users will find the standard Main Window menu bar toolbar and Help system easy to navigate There are four alternative forms of data entry e by drawing drainage system components on the screen and inserting information for each component in property sheets e by entering data from ILSAX files CAD drawing files or GIS files e by direct entry from other programs such as 12d CADApps Advanced Road Design and MX and e by modifying spreadsheet output files created by DRAINS or building such files directly in a spreadsheet program or as an exported file from another program There is also a large choice of outputs screen print outs CAD GIS and spreadsheet files In most cases revised data can be transferred back to the originating programs using these files Installation and updating of DRAINS is quick and easy using a self extracting file named DainsSetup exe that can be supplied on CD ROM or downloaded from www watercom com au The file installs the latest release version of DRAINS which also operates as a demonstration program with a limit of five pipes or channels and restrictions on changes to detention basins and culver
22. storms Add a New Storm Help hi Delete Current Storm Figure 2 73 Synthetic Rainfall Pattern Rainfall Data Storm 4 a of 4 Name Actual Storm on 31 October 2011 Antecedent moisture condition 1 to 4 2 Annual Recurrence Interval pears n a Storm duration mina r5 Ramfall specified in Bo minute intervals Time mine Intensity mmh Oto 5 5 6 Paste Comments 10 20 30 40 50 60 70 a0 Intensity mm h Time mins Add one AARS storm Add Synthetic Storm Add multiple AARS storms Add a New Storm Help Delete Current Storm Figure 2 74 Manual Data Entry of a Rainfall Hyetograph The duration of the pattern and the time step can be set and the rainfall intensities entered directly in the text box labelled Intensity mm h Corrections can be T SB made by locating a value using the spin box for the intensities and altering the 5 14 9 contents of the text box 10 41 35 15 55 61 An average recurrence interval is required to specify factors used to determine a A runoff coefficients in the Extended Rational Method Itis possible to enter values 30 a between 0 1 and 999 years If actual storms are being modelled a rough estimate i a5 og of the ARI should be entered If probable maximum precipitation storms are to be AQ 22 91 modelled a value of 999 might be used 45 bit 50 90 4 It is also possible to enter data from a spreadsheet by setting up two spreadsheet eh columns
23. the unsteady hydraulic method applied in the standard and premium hydraulic models is quite different to method used by the basic hydraulic model The unsteady model in DRAINS solves the full St Venant equations of momentum and continuity using an implicit finite difference scheme with a staggered H Q grid This solution scheme is widely used in other software such as SWMM Links are divided into an odd number of reaches 1 3 5 etc with DRAINS automatically determining a suitable number to use When DRAINS reports the flow in a link it is referring to the flow calculated at this central grid point The method applies the Saint Venant Equations for conservation of mass and momentum in unsteady flow OA oO On a 0 Continuity or Mass Equation 5 17 l H Ala mae Iy a S 0 Momentum _ Equation 5 18 where Q is flow A is cross sectional area H is water surface level tis time x is distance along a channel g is gravitational acceleration Sf is friction slope The calculation procedure applied in DRAINS involves the solution of these equations to determine H and Q at all points in a system at each time step of the simulation Equations are gathered into a matrix and solved allowing for different types of boundary conditions imposed by flows entering pipe and channel systems downstream tailwater levels and the hydraulic features at on grade and sag pits headwalls and other features DRAINS User Manual 5 32 N
24. with the 0 6 allowing for the routing effects in the reach the length of which is related to the area of the catchment through which it runs A A stream lag factor can be applied to allow for different types of channel Indicative values are shown in Table 5 12 Table 5 12 Stream Lag Factors used in WBNM Reach Type Stream a Factor Drowned oya reseno o0 Cog aricaii ooo Modelling facilities based on RORB RAFTS and WBNM have been included in DRAINS The three models have different structures as shown in Figure 6 18 RORB has a well defined structure with nodes located close to sub catchment centroids Routing is only carried out in the stream reaches There is modelling of losses at nodes but no routing By contrast RAFTS can carry out routing at nodes representing sub catchments and also in stream reaches where flows can be translated or routed using the Muskingum Cunge method based on the reach cross section and roughness The routing within sub catchments differs from RORB and WBNM in that flows are commonly routed through 10 successive non linear storages as indicated in one of the sub catchments in Figure 5 18 In WBNM routing occurs at the sub catchment nodes and in stream reaches that convey runoff from upstream sub catchments through the local sub catchment Like RAFTS it is flexible and can be set out in different configurations To fit these different structures into the DRAINS framework it has been necessary
25. 0 000 0 000 0 388883 0 000 0 000 0 0 0 444444 0 000 0 000 0 000 0 5 O 000 0 000 0 000 0 555556 0 000 0 000 0 000 0 611111 0 000 0 000 0 0 0 666667 0 000 0 000 0 0 Of22222 0 001 0 000 0 0 1 Orr SOOT 0000 0 001 0 833333 0 001 0 000 0 001 0 288883 0 002 0 000 0 002 0 344444 0 002 0000 0 002 0 002 O000 0 002 1 05556 0 002 0 000 0 002 1 11111 0 003 0000 0 003 1 16667 0 003 0 000 0 003 q 22222 0003 0 000 0 003 Flow rate cu m s 0 20 40 60 80 Time mins Figure 4 2 DRAINS Hydrograph Outputs for an ILSAX Sub Catchment 4 2 7 Hydraulic Calculations a General Once hydraulic calculations begin DRAINS determines the inflow into the pipe and channel system at each time step At each node the following flows are combined flows off areas on the local sub catchment any overflows from upstream pits or detention basins that are directed to this destination any baseflows or flows from user provided inflow hydrographs applied at the surface for a pit or simple node This surface flow is assumed to enter the system without restriction at a simple node detention basin culvert or bridge For an on grade or sag pit the pit capacity relationship defined in the Pit property sheet is applied to estimate the inflow rate as described in Section 2 3 2 For Design calculations a pipe system will be sized to carry all flows that enter the system The only overflows will be the bypasses caused by restrictions on inlet capacitie
26. 1 2 3 and 4 Table 5 5 Antecedent Moisture Conditions Description Total rainfall in 5 days preceding the storm mm 2 Rather dry 0 to 12 5 Rather wet 12 5 to 25 Saturated Over 25 DRAINS User Manual 5 10 November 2014 For the curve and AMC selected the model calculates an infiltration loss in each time step This is subtracted from the rainfall inputs to the pervious area Values of parameters involved with various combinations of soil types and AMCs are set out in Table 5 6 Table 5 6 Infiltration Model Parameters Initial Infiltration Rates mm h for AMCs Soil Type sollte O Faret 25 aT o d a A a 2 2 Antecedent Rainfall rm E for AMCs Users also can also provide their own values One method to do this is to analyse daily rainfall records and on a spreadsheet calculate the rainfalls for the 5 days preceding each day Daily rainfalls can then be ranked and the antecedent rainfalls for the highest 100 rainfalls say can be analysed as shown in Figure 5 10 which gives results for Observatory Hill rainfall records in Sydney From the mean or median antecedent rainfalls and classification numbers a most likely value of AMC can be selected 040160 Nerang Gilston Road 1887 2007 bits missing xls Compatibility Mode Microsoft Exce Page Layout Formulas Data Review View Developer Acrobat Be amp Arial jio jA ate y BT U H O A Clipboard Font E Wrap Text
27. 1 23 Frequency factors 5 17 Full hydrodynamic model 5 30 Gauged catchment data 5 14 Gauging rainfalls and runoff 4 15 Generic Pit Inlet Capacity Spreadsheet 3 4 GIS file formats 5 43 GIS file imports 3 4 Grassed area 1 15 5 3 Greenfields drainage systems 4 11 Gully pit 2 4 Hardware lock 1 4 head losses 5 33 Headwall 2 34 Headwall property sheet 2 34 Headwater level 2 34 HEC 22 5 27 HEC RAS 2 35 Help 1 7 Help system 3 37 High early discharge pit 2 23 Horton s infiltration equation 1 4 5 5 5 9 Hydraulic analysis 4 5 Hydraulic conductivity 5 41 Hydraulic grade line HGL 1 20 Hydraulic models A 19 Hydrograph 2 8 translation 1 29 Hydrograph attenuation 5 18 Hydrograph translation 5 18 Hydrograph producing models 5 2 Hydrographs 1 21 Hydrological calculations 4 3 Hydrological model specification 1 7 Hydrological models 1 6 2 11 Hydrological models data base 2 39 Hydrology 5 2 Hyetograph 1 7 Hyetograph data base 2 40 ILLUDAS 1 4 5 1 ILLUDAS SA 5 1 ILSAX 1 4 5 1 ILSAX file imports 3 9 ILSAX hydrological model 5 3 ILSAX Hydrological Model 1 2 Impervious area 1 15 Impervious areas 1 15 Import DB1 data base file 2 48 Index sheet 3 13 DRAINS User Manual 2 Infill developments 4 13 Infiltration 5 3 Initial loss 5 3 Inlet control for culverts 5 39 Input options 3 1 Installation of DRAINS program 1 5 Integrated linkages 4 11 Inter allotment requirements A 4 Intercep
28. 1 3 5 19 lag parameter 5 20 stream lag factor 5 20 Weir special for basins 2 27 Weir coefficient 2 35 Weir equation 5 40 X Y coordinates cross section 2 35 X Y coordinates irregular channel 2 29 X Y coordinates overflow route 2 53 X Y coordinates pits and nodes 3 26 Zoom extents 3 16 Zoom factor 3 13 Zoom window 3 16 November 2014
29. 176 3 dsection 3 16 0 132 1 13 0 15 Pit 2 Pipe 2 CarA 2 80 Add 3 153 0 781 0 08 0 062 0 027 Node 4 2 0 027 dsection 134 0 078 0 74 0 06 Pit 4 1 0 0 sross Roar 0 0 0 0 Pir4 2 PipeA2 CarA 2 80 Add 3 252 0 922 0 08 0 074 0 052 Node 4 2 0 052 dsection 185 0 093 0 85 0 08 Pit 4 1 0 13 0 13 srossRoac 11 83 0 03 0 74 0 02 Pi4 3 PipeAs CatA3 0 781 0 048 0 02 Node 3 0 02 dsection 115 0 072 0 71 0 05 Pit4 3 Pipe 3 CatA3 0 922 0 056 i 0 033 Node A 3 0 272 dsection 4 6 0 143 1 22 0 18 5 PitB 1 PipeB 1 CatB 1 0 688 0 408 0 121 Node B 1 0 103 dsection 2 48 0 113 1 0 11 5 partial 0 358 0 123 PitA2 0 023 dsection 117 0 072 1 0 07 100 PitB 1 PipeB 1 CatB 1 0 825 0 483 0 241 NodeB 1 0 203 dsection 3 59 0 137 11 0 16 100 partial 0 427 i 0 254 Pit 2 0 163 dsection 2 6 0 116 1 45 0 17 7 5 PiC 1 PipeC 1 CatC 1 0 707 0 29 0 096 WNodeC 1 0 103 dsection 2 48 0 113 1 0 11 5 partial 0 259 F 0 103 100 PitC 1 PipeC 1 CatC 1 0 845 0 347 l 0 19 NodeC 1 0 202 dsection 3 59 0 137 117 0 16 100 partial 0 307 f 0 202 _ 32 a3 MOES 34 35 This table follows the pattern set out in the Pine Rivers Shire Council now the Moreton Bay Regional Council 36 in Charts 3 and 10 of the Stormw ater Standards in its Civil Infrastructure Design Manual 2005 37 38 The results are presented for pits and associated sub catchments pipes and overflow routes arranged in top to bottom order 39 Information is not presented for nodes used in the DRAIN
30. 1984 b Manning s equation or c more simply by dividing a flow path length by a speed to obtain a time Sub Catchment Data La Ca Sub catchment name Cat K1 Sub catchment area ha 0 528 Hydrological Model e dete Note The additional times you m speci will be added to the times Default model calculated fram flow path length slope and rougness to get the total o i i You specify times of concentration Faved Supplementary Grassed Percentage of area 2 55 0 Additional time ming 25 Flow path length rm 30 40 Flow path slope 2 0 10 Flow path roughness 0 015 O20 Lag time minutes T Cancel Customise Storms Help Figure 5 7 Sub Catchment Property Sheet with Text Boxes for Entry of Data Table 5 3 Surface Roughness Factors Source Woolhiser 1975 In DRAINS a kinematic wave flow time can be added to a constant time as follows Total time Constant time which can represent property drainage time plus gutter flow time Overland flow time calculated from length slope and roughness Equation 5 4 Users can specify the times associated with paved supplementary and grassed areas as a a constant time b a constant time now called an additional time plus a kinematic wave calculation or c a kinematic wave time only by specifying the additional time as zero Up to 2005 there was a third term that modelled street gutter flow times using equations based on road cross
31. 287 099 101 642 No 183 1x Ku 0 290 69 90 817 No 184 1x Ku 0 5 290 762 11 228 No 185 1x Ku 0 301 465 7 398 No 189 1x Ku 0 329 035 0 738 No 186 1x Ku 348 224 3 153 244 373 74 71 352 249 428 594 103 605 250 524 055 120 993 275 589 929 149 354 80796 605 33 158 529 80803 615 816 169 016 80817 633 512 176 553 280 212 647 7 638 No 188 1x Ku 227 745 7 705 No 187 1x Ku 352 399 137 694 305 399 308 87 872 No 437 1x Ku 348 224 87 778 252 348 224 12 62 269 196 168 7 317 16856 404 291 108 029 16873 194 841 101 202 16885 218 325 92 737 16897 oioioigoicoioioicoicoicoioisoioicoioicoioioicoiscoioiscisoisoisC Culvert 0 5 499 953 114 681 No 15961 Figure 3 43 Transferred Data The results from a Design can then be transferred using the Copy Results to Spreadsheet option from the Edit menu This can be pasted into a second worksheet with the tag Design or Minor as shown in Figure 3 44 Home Insert Bookl Microsoft Exce Page Layout Formulas Data Review View Developer Acrobat Al f DRAINS results prepared 12 January 2011 from Version 2011 01 A B C D TTE T DRAINS results prepared 12 January 2011 from Version 2011 01 PIT NODE DETAILS Versions Name Max HGL Max Pond Max Surfa Max Pond Min Overflow Constraint HGL Pit B 1 706 57 Pit B 2 706 21 Pit B 3 705 68 Pit B 4 705 31 1 Pit B 5 704 35 Pit B 6 704 13 Pit B 7 703 57 NB 702 59 N4 701 97 N5 701 84 N7 7
32. 3 3 1 Introduction DRAINS provides several options for viewing data on screen in addition to usual Windows facilities such as scrolling bars The options available before calculations are performed are demonstrated in this section using the Toowoomba Estate drn example that is ready to run in Design mode which will define the pipe diameters and invert levels Draw Run Help 3 3 2 Screen Presentation Options Customise Text You can vary the way that a drainage system is presented on screen Index Sheet using options that are mainly included in the View menu Figure 3 18 Zoom Factor a Customise Text room aoon Zoom Extents The Customise Text option at the top of the View menu produces the Pan dialog box shown in Figure 3 19 By selecting options here you can change the information provided as indicated in Figure 3 20 Many Property Balloons choices are only available after a Design or Analysis run The custom Overflow Routes display numbers are coloured purple to distinguish them from names of Sub Catchments components black and numerical outputs black green blue and red Aaa This dialog box can also be opened by right clicking on the name of any v Status Bar component though not the component itself Background Background Colour b Index Sheet Extend Drawing Area Selecting Index Sheet from the DRAINS View menu produces the view Crop Drawing Area of the system shown in Figure 3 21 The rectan
33. 3 5 6 Hydrograph Outputs in TWRLOW Format miesenie eea a a a A EA 3 35 35 7 OUTPUTS tO Linked Ap pIIGAtlON Sra acs ccdete ss oedectetacdeetetncadecue iene ce vieas EE 3 35 35 9 Merge OuIputs and INPUTS onucuient ee Oe ene eee 3 35 3299 Template FING XDOMS sacs daca ees a eden Ses heen e aaa jac aaa es aa te E 3 37 320 MHEID ODUON Seni aen a ne ete act nett eels le be Pre T del ae dnl wll 3 37 OPERATIONS AN IAE dU UON nets scse aceasta dane sauce iacasieeadiedateas dedveadedutiags tdateeasededieenedeteedunted andar 4 1 42 DRAINS WOKNOS dssicioesaicia cxniosaccraiacosceniosascrasosquseaiesqsouaiocasceaiccaiexaiosesczaiacquees 4 1 ZW S a EE E E E EEE 4 1 DRAINS User Manual ji November 2014 AZZ Programme a a a a a a 4 1 4239 Datastorage ANG Files vxawtance asus tenets E E A 4 1 AiZA PIOCESSES onnen a E A A a ae eae at ce need eee 4 2 42o Mmiual Processes eiin E acntsagatesuaen naaataindel baa dactatade 4 3 426 Hydrological Calculations aes a E E a E 4 3 A277 Hydraulic Calculations asaan a a e tiyniad aie iaiMde eames 4 4 M22 KC ANDNAON na e a T a A ae ae ieee he 4 7 4 2 9 Interpretation Of Results ce ccccccccceeeeeceeeeeceeeeeeeeeeseacessacessaeeeseaeeeseaeesseueessaeeeseneeseaeeeees 4 7 AZ VO Desin Ir LOCC CO UNCS sarie Szsctotcl satis sainen wna cedst a seis iiainesnelcodaaaeadeees 4 8 43 4ADDIVING DRAIN O oero eae nen VoL eeoreeore bane eae 4 11 Ae Mega iON sei a tetas siete Mabie E dali huddahinuaedalbethidabe
34. 3 Loss and Routing Models HYETOGRAPH Rainfall x n S N 3 N NS AS Time N aN ok BYPASS lt FLOW PIPE oe impervious area n not pervious area directly connected eey cone SUB CATCHMENT Flowrate HYDROGRAPH PIPE or CHANNEL Kid P Time DETENTION STORAGE OUTFALL A 5 4 November 2014 DRAINS User Manual Figure 5 4 The Layout of the ILSAX Model Since this is an event model conditions at the start of each storm event must be established by defining a value of the antecedent moisture condition AMC for the soil underlying the pervious portions of the catchment The loss model subtracts depression storages from all surfaces and calculates additional losses for grassed or pervious areas using Horton s infiltration model The soil type and AMC parameters are easily understandable and can be related to identifiable soils and rainfall depths preceding a storm Results are quite sensitive to the AMC and users must consider the effects of their choices using sensitivity studies Despite this few problems with employing this model have been reported The model relies on times of travel as the main parameters used in routing These can be determined to an acceptable level of accuracy for urban catchments but are very variable for rural catchments Thus while the ILSAX model can be applied to pervious sub catchments of a drainage system it is not strictly applicable to rural catchments This reflects the lack of s
35. 4816 0 033 Cancel 482 25 0 036 Faste Table Figure 2 42 Specification of a Pump from a Detention Basin The pump starts operating when the storage water level rises above 222 0 m The pump rate increases from 160 to 300 L s as the water level rises to 223 5 m reflecting the characteristic head versus discharge relationship for the pump and the friction and shock losses through the delivery pipe A worksheet in the DRAINS Utility Spreadsheet Section 3 2 3 can assist in developing an appropriate pumping relationship which can be imported into the Pump property sheet using the Paste Table button Pump links can be bent of kinked like those for special orifices and weirs 2 3 10 Prismatic Open Channels The Prismatic Open Channel property sheet shown in Figure 2 43 enables easy entry of the parameters needed to define trapezoidal Rectangular or triangular channels of uniform cross section and slope Rectangular channels have zero side slope factors and triangular channels have a zero base width If calculations determine that the channel depth exceeds that specified in this property sheet the sides of the channel will be extrapolated upwards and a warning message will be provided DRAINS does not allow for overflows from channels In the majority of cases where overflows will follow the same route as the main stream channel they can be accommodated by defining a channel cross section large enough to carry them If necessary t
36. 53 K entry 0 5 Overflow level m 704 2 Hotes Figure 2 53 Headwall Property Sheet The overflow level entered on this sheet is critical to the operation of this component at higher flows As water levels increase to this level the flow into the pipe is governed by the culvert equations described in Section 5 8 2 Once this level is reached the inflow is assumed to be that corresponding to the nominated overflow level while the headwater level the level of the water level upstream is assumed to be governed by the property sheet for the overflow route provided which takes the form shown in Figure 2 38 and Figure 2 39 Assuming the overflow rate to be the upstream flowrate minus the pipe capacity DRAINS calculates a flow depth based on the weir or elevation discharge relationship and adds this to the overflow level to obtain the headwater level This process will set a headwater level that is slightly conservative as the depth of the overflow path flow is not considered in determining the flow through the pipe This is necessary to avoid considerable iterative calculations caused by the splitting of the flows and the uncertainty of the effects of changing flowrates on the calculations for downstream pipes An alternative way of handling this situation is by terminating an open channel at a detention basin and starting a pipe from there The headwall can be used to model culverts as described in the next section DRAINS User M
37. Act Together State 4 The Storages Empty Figure 5 33 A High Early Discharge HED Pit OSD storages are usually controlled by circular orifices with the discharge equation being GSC 7 d 2gh Equation 5 7 where C is a contraction coefficient taken as a constant of 0 6 in DRAINS d is the orifice diameter m g is the acceleration due to gravity m s and h is the height from the water surface to the centre of the orifice m 5 8 4 Infiltration The second panel on the detention basin property sheet Figure 2 37 displays data that can be used to model stormwater infiltration out of a storage that has a permeable base and or permeable sides The calculations involved are simple the exposed surface of the storage at any time is multiplied by the hydraulic conductivity to define an outflow The greater the depth in the storage the larger the infiltration rate Allowance is made for storages having permeable or impermeable floors and walls Infiltration procedures are discussed in detail in Argue J R editor 2004 WSUD Basic Procedures for Source Control of Stormwater University of South Australia Water Resources Centre Adelaide Indicative values of hydraulic conductivity p 44 are given in Table 5 24 Specific values for a site can be obtained from on site tests and modified using factors provided in the above publication Table 5 24 Hydraulic Conductivities for Infiltration Calculations Soil Type Hydra
38. Analysis Runs C Orange Rational Method Cancel Note Ifyou warto edit a model other Delete Default Model than the def model make it the default m7 temporarily Edit Default Model Add ILSAx Model se a Add Rational Method Model 5 ea Add Extended Rational Model Add Storage Routing Model Help Figure 1 38 Hydrological Model Property Sheet for the Rational Method There are three choices on the type of rational method procedure to be used The version from Australian Rainfall and Runoff 1987 is selected as shown in Figure 1 39 Rational Method Moda bodel Name Orange Rational Method Rational Method Procedure Imperious Area C10 Value 0 9 C0 General Pervious Area C10 Value 0 26 f AS 3500 3 2009 These C10 values are 10 year ARI unott coefficients They will be adjusted automatically to suit the AAls specified for major and minor storme Uk Cancel Help Figure 1 39 Rational Method Model Specification The 10 year ARI runoff coefficient C for the pervious area is set at 0 26 based on a 10 year ARI 1 hour rainfall intensity MT of 37 2 mm h entered into Equation 14 12 in Australian Rainfall and Runoff 1987 Cio 0 1 0 0133 x h 25 The selection of a rational method hydrological model acts as a switch that affects other parts of the program When the Rainfall Data option is selected in the Project menu the property sheet that appears Figure 1 40 is different to th
39. C1 n aicn as n gn A cn g 2 1 Fa For Help press F1 Num Figure 5 35 DRAINS Spreadsheet Output displayed in an Editor 5 10 5 TUFLOW TS1 File Formats Using the File Export gt Tuflow TS1 Files option described in Section 3 5 6 DRAINS can transfer calculated hydrographs to TUFLOW and other programs in the format shown in Figure 5 36 which can readily be imported into spreadsheet programs File created from C 2007 DRAINS Files Manual Example Files March 2007 Storm ewenti ARsE 100 year average 140 mm h Zone 1 Timestep 0 111111 min WNWumber of timesteps 655 WNumber of catchments 5 5 053 start Index 1 1 1 1 1 End Index 853 653 055 053 053 Time minj cat 5 Cat 4 Cat 3 Cat 2 Cat 1 15 minutes storm PrRrerRPFeRrerRPerRe ROO 0D A 0A 0A oOo 111 0 222 0 333 0 44 0 556 0 667 0 7s 0 689 0 000 0 111 0 2292 20 333 0 444 0 556 0 667 0 000 0 000 0 000 0 000 0 001 0 001 0 002 0 003 0 003 0 004 0 005 0 005 0 006 0 007 0 007 0 000 0 000 0 000 0 000 0 003 0 005 0 007 0 010 0 012 0 015 0 017 0 019 0 022 0 024 0 027 0 DRAINS User Manual 000 0 000 0 000 0 000 0 001 0 002 0 003 0 003 0 004 0 005 0 006 0 007 0 008 0 009 0 009 0 000 0 000 0 000 0 000 0 000 0 001 0 001 0 002 0 002 0 002 0 003 0 003 0 004 0 004 0 004 0 O00 O00 O00 O00 O00 DOU DOU
40. Click Help for more details High Earty Discharge Figure 2 32 Detention Basin Property Sheet DRAINS applies as a default an elevation surface area relationship rather than an elevation storage volume relationship which will be easier for users since volumes are calculated from surface areas in most cases Previously developed models that specify volumes shown in Figure 2 33 are still supported in DRAINS but both types of elevation based relationship cannot be used in the same model Elevation volume relationships can be used in projects by selecting an option in the Project Options property sheet opened from the Project menu When working with elevation surface area relationships DRAINS employs an interpolation procedure for calculating volumes corresponding to certain elevations with a fitted curve rather than the set of straight line segments The elevation surface area relationship must use levels to the same datum as the rest of the drainage network Relationships can be calculated in a spread sheet and pasted into DRAINS Using the Paste Table button Numbers must be arranged into two columns as shown to the right These are then selected and the Edit Copy option is used to place the data on the clipboard Transferring from the spreadsheet program to DRAINS the data can be entered using the Paste Table button The Low Level Outlet Type connecting to a pipe option buttons offer five choices e anorifice acting as
41. Commons Attribution Australis Licence Water links Z Water Act 2007 Water Regulations 2008 Water Market Reports Water Dictionary Gi publications News Contact Us Stay informed SUBSCRIBE here Available on th App Store TMIPACNATER De ITURE Figure 2 61 Bureau of Meteorology Website DRAINS User Manual 2 40 November 2014 Rather than recommending that the new design rainfall estimates be adopted in preference to the older ones from Australian Rainfall and Runoff 198 the initial advice from these organisations is to use these cautiously perhaps because these estimates are lower than the 1987 values at many locations Other changes are that the new intensity frequency duration I F D values are expressed as depths of rainfall over a number of durations rather than intensities and that frequencies are defined as exceedances per year EY and annual exceedance probabilities AEPs in rather than average recurrence intervals ARIs It appears that this situation will take some time to sort out so DRAINS retains inputs for older procedures and will accommodate the new procedures when users require these While the Bureau has issued new rainfall intensity or depth information there is as yet no new rainfall temporal patterns to accompany these New patterns will not be available for two or more years and it appears that the only choice for designers requiring hyetographs will be to use the new I F D da
42. D S no D S yes Headwall U S no U S yes U S yes U S yes U S yes D S yes D S no D S no D S no D S yes Culvert object U S no U S yes U S yes U S yes U S yes obsolete D S no D S yes D S yes D S yes D S no Bridge U S no U S yes U S yes U S yes U S yes D S no D S yes D S yes D S no D S no Pit U S yes U S no U S no U S yes D S yes D S no D S no D S yes Notes 1 If a node has pipes both upstream and downstream it acts as a closed junction and can be pressurised with the HGL rising above the surface Generally however it is better to connect pipes through sealed or unsealed pits where a head loss can be specified 2 You need to be aware that nodes will accept all flows coming to them and check whether this is realistic Where there are likely to be overflows a pit should be substituted if the node is in a pipe system and a detention basin if the node is in an open channel system 3 In the standard hydraulic model overflows are permitted from a node but not if there is also a pipe or channel leaving the node For an open channel where overflows will run along the banks you should raise the height of the channel cross section so that overbank areas are included The open channel downstream will need to be defined as an irregular open channel Where channel overflows are to be directed out of a channel you can place a detenti
43. Data can also be inspected by exporting tables to a spreadsheet via the Windows clipboard using options in the Edit menu Part of a table is shown in Figure A 4 The facility of viewing long sections of pipelines and transferring them to CAD programs is not available in the Viewer x H ier gt Booki Microsoft Excel ol X Home Insert Page Layout Formulas Data Review View Add Ins Acrobat Pz Al v fe PIT NODE DETAILS xi A B c D E F G H l J K L M N o p Q R S T TE 1 PIT NODE DETAILS Version 12 2 Name Type Family Size Ponding Pressure Surface Max Pond Base Blocking x y Bolt dowr id Part Full Inflow Pitis gt 3 Volume Change Elev m Depth mjinflow Factor lid Shock Los Hydrograph Pit and 4 cu m Coeff Ku cu m s Node Data 5 PitA 1 Sag Sutherlan kerb inlet 30 5 32 5 0 3 0 0 5 309388 9 1251083 No 11xKu No New 6 PitA 2 OnGrade Sutherlan kerb inlet with 0 85 0 5 32 3 0 0 309396 2 1251067 No 21x Ku No New 7 PitA 3 OnGrade Sutherlan kerb inlet with 0 85 2 30 7 0 0 309436 1 1251002 No 3 1xKu No New 8 Outlet Node 30 1 0 309458 9 1250973 17 9 PitB 1 Sag Sutherlan kerb inlet 20 5 30 9 0 2 0 0 5 309436 6 1251015 No 41x Ku No New 10 PitC 1 OnGrade Sutherlan kerb inlet with 0 851 5 30 8 0 0 309428 1 1251002 No 61x Ku No New 11 Outlet2 Node 30 0 309448 1 1250976 19 12 13 DETENTION BASIN DETAILS 14 Name Elev Surf Area Not Used Outlet Tyg K Dia mm Centre RL Pit Family Pit Type x y HED CrestRL Crest Lengid 15 16 SUB CATCH
44. Default model f more detailed data calculated fram flow path length slope and rougness bo get the total times of concentration O You specify This can be the sum of constant Paved Supplementary Grassed times for one or Percentage of area 4 Ea EH E more flow path Additional time mins E En 7 segments 40 0 Flow path length m 30 Flow path slope 10 1 Flow path roughness 0 015 0 015 0 035 Lag time minutes A flow time can be calculated from these three inputs This varies with Pe the mean intensity of each rainfall pattern It is added to the constant Customise Storms additional time Help Figure 2 17 Sub Catchment Data Property Sheet For each of the three land uses there are two flow components a constant component and a kinematic wave calculation component A typical flow path is shown in Figure 2 18 consisting of ae ane aw Roof and Property Drainage system Bypass Flow or Oy erflow Destination Pit Figure 2 18 Flow Paths to a Pit a aconstant time for the segment from the roof of the furthest building in the sub catchment to its property boundary usually 1 minute for a new property drainage system or 2 minutes for an older one with possible blockages b atime to be calculated by the kinematic wave equation for the overland flow segment using the specified length slope and surface roughness n and DRAINS U
45. Grassed 4 Area i ee mene od oy C2 Renee peeseSeeene Pit at Sub Catchment Outlet Figure 2 15 ILSAX Catchment Model Land Use Types a SUB BASIN MAP i a SUB BASIN MAP DIRECTLY CONNECTED PAVED AREA SHADED CONTRIBUTING GRASSED AREA SHADED i Roof 1 l minute Roof 1 1 minute J j not connected isochrones i not connected isochrones iY Roof 2 a y P 4 iy aE CLAY Roof 2 directly connected GY directly connccted P Ps i Tr PA Inlets to Inlets to A K storm drain storm drain Figure 2 16 Original Definition of Land Use Areas for ILLUDAS Model The full form of the Sub Catchment property sheet for the ILSAX Model is shown in Figure 2 17 with the more detailed data option chosen in the check boxes labelled Use Figure 1 23 in the previous chapter displayed the abbreviated data option In both this and the more detailed data option you must enter the total area in hectares and the percentages of the three land use categories that make up the total area The detailed option in Figure 2 17 requires additional information to establish times of entry using different flow path components applying the kinematic wave equation described in Section 5 3 2 d DRAINS User Manual 2 12 November 2014 Sub Catchment Dat Sub catchment name Cat K Sub catchment area ha 0 528 Use Hydrological Model edda Note The additional times you a cae specify will be added to the times
46. HGLs for the Selected St worst Case major storm 1 10m Cover 0 99m Cover 0 95m Cover 705 300 r 4 803 HESAN r04 266 E 704 152 FER ee 703 552 PitB 5 Length 11 4 metres Diameter 600 mm Pit BE Pond AL 705 500 Fipe Slope 1 00 Omas 0 570 cums Ymar 2 02 mts Figure 4 7 Long Section Display from Pop Up Menu for a Pipe The design procedure also determines the sizes of inlet pits using a method that was first presented in the Queensland Urban Drainage Manual Neville Jones amp Associates et al 1992 The method focuses upon the flows along overflow routes It sets appropriate safety levels for these in terms of tolerable flow depths in the minor and major storms and a maximum velocity x depth product A point along each flow path must be nominated by specifying a cross section from the Overflow Route data base as shown in Figure 4 8 a percentage of downstream catchment contributing to the flow and a longitudinal slope The basis for selecting the percentage of the downstream sub catchment is explained in Section 2 3 6 Overflow Route OF B Basic Data Cross Section Data Shape 8 m wide road half section Safe Depths and How Rates Safe Depth for Major Storms m 02 p default values f je on j Use default values for this cross section eisai en Mia eee fl os Safe Depth x Velocity sq m sec 0 4 of downstream For Major Storms catchment fow cared 50 Safe flow 0 567 cu
47. Lo Fo ae aol A ol Ofc 61 2c ane nn a E a a 5 22 So Pu me GC 01 2 Emer etter nes Renee ere et te Pe ee renee ene eee tet eee er eee ee eee ee eee 5 22 552 Pit Inlet Capacities im DRAINS viscc hss cee foto bigac a a A E AA A 5 23 5 5 3 US Federal Highway Administration HEC22 Procedures cccccccseeeeeeeeeeeeeeaeeeeesaaeees 5 28 20 PIPE SYSE 6 18 S aser E O E E 5 31 30T General asa a O ee ee 5 31 502A Pipe Desom C alc latonS serai a E S 5 32 5 6 3 Basic Hydraulic Calculations assia a a aa a a a a a a Aa 5 32 5 6 4 Unsteady Flow Calculations in Standard and Premium Hydraulic Models 00008 5 32 20 9 PPE Fricot EQUATIONS ms ctos asa oie Siaa aTa 5 33 566 PitPress re CANOES a R E E a E A 5 34 SOT Tali Aver ELEVE S aa a E E aude ancra tcdasenabeesuankes 5 36 97 Mydraulics o ODS CANINES sereset r TT 5 36 909 Detenion Basini AYaraulC Serado n E E E EEEE ENEE 5 3 ION De Ui go Reaen eer a Ne rene en Ent ry atne DE ene ern er E 5 3 50 2 OVEMIOWS FOM BASINS anasare ate cetera aecccoiean ce A 5 39 5 8 3 On Site Stormwater Detention cccccccsssccccesseecceeseeccseseeeceeseecceueeessageeesseueeesssaseesssneees 5 41 2024 AMN AUO eao A a A aetei ceasing 5 42 DRAINS User Manual lil November 2014 99 CUIVEFEahG Budge nV ClaUilGS iesean EERIE 5 43 Sl CUVE isana A a A E eemeccan ae 5 43 992 INO OSS S aanse a a E 5 43 STO RIC EONA Oa E E oe ere er ee ee 5 43 ONE E E g
48. N e gt Runoff Time I Hydrographs l ae 7 Open Channel Flow x ty lt system _ gt Figure 1 2 Operation of the DRAINS Rainfall Runoff Simulation Model Incorporating the ILSAX Hydrological Model and Hydraulic Calculations The design of a piped drainage system can be performed automatically followed by an analysis and results can be checked viewed and exported as CAD computer aided drafting files GIS geographical information system files and spreadsheet tables In addition to the ILSAX model three other hydrological models are available as options in DRAINS a Peak flowrates can be calculated by the rational method traditionally used for calculating flowrates for piped urban drainage design Using the formula Q C 1 A it converts a statistical rainfall intensity to a flowrate Q using a runoff coefficient C and catchment area A see Section 5 3 3 The rational method s main drawback that it does not calculate flow hydrographs and it is gradually being superseded by hydrograph producing methods DRAINS includes a search procedure that determines the time duration that gives the greatest value of Q C I A thus resolving partial area problems DRAINS User Manual 1 2 November 2014 b An optional extended rational method ERM model that produces flow hydrographs based on rational method calculations is also provided with the rational method for modelling detention systems c DRAINS incorp
49. Pipes are sized to carry flows of a minor ARI from 2 to 10 years and a check is made to ensure the safe working of the system during a major storm event with an ARI of about 100 years So far DRAINS has performed the design determining pipe sizes and invert levels You can now also perform an analysis using the 100 year ARI 25 minute rainfall pattern Simply run Analyse major storms from the Run menu to produce the results shown in Figure 1 35 DRAINS User Manual 1 20 November 2014 3 Orange2 DRAINS la x File Edit Project View Draw Run Help 3 Pit 2 HGL AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 o D S E g e Gal lt a BB s we z S O Q s File Edit Properties ARAR 2 year 25 minutes storm average 40 2 mm h 22 21 9 21 8 E 21 7 21 38 Outlet Obvert L 0 051 Qpa gt m anlo e Aca Scene ase aaa 0 013 5 i 0 039 21 5 a i 21 4 Pa a a MM 0 20 40 60 80 100 a Time mins A 0 024 oom 8 0 066 aiid 3 Pipe 2 Hydrograph AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 of x 3 Pipe 2 Hydrograph AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 Lo e us File Edit File Edit Properties Total volume 17 5 cu m 0 02 Time Flowrate 0 018 min o a In all DRAINS runs E sau 0 1 i 02 tables of results are 0 014 E 0 012 04 available as well as 5 a Pr i 0 6 a7
50. Tears 10 Years 1 5 Years Bj 2Yana 1 Yeanlower conve a RWE a T l Figure 2 68 Output from CDIRS Procedure Next click the Coefficients button to open Figure 2 69 Click the Copy Table button and then go back to DRAINS to the Paste BOM format table dialog box and click the Paste Table button which displays Figure 2 70 The text shown is a set of polynomial coefficients in csv comma separated variable format When the OK button is clicked the desired storms are added to the rainfall pattern database as shown in Figure 2 71 As an alternative you can select IFD Table rather than Coefficients in the BOM output that shows the IFD curves and go through a similar process c Entering Synthetic Storms for the Extended Rational Method As an alternative to working with design storm patterns from Australian Rainfall and Runoff 1987 the Extended Rational Method can be applied using synthetic patterns derived from the local intensity frequency duration l F D relationships DRAINS User Manual 2 44 November 2014 6 u born gov eu j p X Welcome to the FD Program File Ede View Favorites Tools Help z amp Australian Government h 7 Bureau of Meteorology Home IFD Table FD Chant f Ae Print c ns Help coeffs Polynomial Coefficients Table Location 35 1258 139 775E NEAR Murray Bridge SA issued 29 8 2012 List of coefficients to equations of the form logell A B x loge
51. The Customise Storms button near the bottom of the ILSAX model Sub Catchment property sheet allows special features to be chosen using the property sheet shown in Figure 2 24 These features are useful in special studies involving gauged rainfall and flow data or where you wish to explore the effects of varying the rainfall intensity pattern and timing of storms over the catchment area Customise storms for this sub catc OF e For minor storms Time lag T mins Cancel Rainfall multiplier Run Uze Stom Help Smiths Pluviograph 23 July 1998 al 2 Bell Street Fluviograph 23 August 1998 ARARA 100 year 25 minutes storm average fy mmh one 1 F ARAA 100 pear 30 minutes storm average 69 mmh one 1 ARAA 100 pear 45 minutes storm average 53 mmh one 1 ARAA 100 pear 1 hour storm average 43 8 mmh one 1 ARAR 100 pear 1 5 hours storm average 33 9 mmh one 1 ARA 100 year 4 hours storm average 28 2 mm h one Smithe Pluviagraph 23 July 1998 Bell Street Pluviograph 23 August 1998 C For major storms Figure 2 24 Property Sheet for Customising Storms You can select a particular storm to apply to this sub catchment in Design or Analysis calculations The storm is selected from the rainfall pattern data base using the list box shown A time lag can also be specified and the storm patterns can be multiplied by a constant rainfall multiplier These allow for the following situations e Areally var
52. also allows a new data base to be loaded as the standard data base Draw Run Help Customise Text 2 2 5 The View Menu Index Sheet l l l Zoom Factor This menu provides options for rE T E viewing data and results in different ways Zoom Extents Pan It controls what is shown in the ia Balloons Main Window See Section 3 3 Overflow Routes for a description of the options Sub Catchments Toolbar Status Bar Background Background Colour LISIS SJS Extend Drawing Area Crop Drawing Area Trim Drawing Edges Last Run Report 2 2 6 The Draw Menu pumaka This duplicates the Toolbar choices Selecting an option has the same effect as clicking on a button in the toolbar DRAINS User Manual 2 2 Import DXF file ESRI 5hapefiles Mapinfo MIF Files LD File Advanced Road Design File ILSAX Files Merge File DRAINS Database DB1 File DXF Long Section DXF Plan ESRI Shapefiles Mapinfo Files 12D Connection Data File Advanced Road Design File Tuflow TS1 Files Merge File Drains Template File Project View Draw Run Help Undo Redo Copy Data to Spreadsheet Copy Results to Spreadsheet Copy Check HGL to Spreadsheet Paste Data from Spreadsheet Find View Draw Run Help Hydrological Models Rainfall Data Select Major Storms Select Minor Storms Options Description Pipe Data Base Pit Data Base Overflow Route
53. and Screen Print Outs Section 3 3 2 described the various screen displays that are provided by DRAINS prior to run calculations Additional displays become available once a run is made These include hydrographs HGL level plots tables of flowrates and HGLs Data and results can be printed from many of the display windows using the File and Edit options in their windows such as the hydrograph display in These can also be copied to reports and calculation files You can also use the screen capture techniques available in all Windows applications such as the Print Screen key and Alt Print Screen keys or specialist screen capture programs to produce outputs such as Figure 3 34 DRAINS User Manual 3 22 November 2014 3 Penrith ARR87 Example Standard DRAINS Pipe 3 Maximum Flow and HGLs for the Selected Storm L X File Edit Project Vi D R Hel ss X0vvVvVvSSSSSSS NN Sams I i n Worst case minor storm x 3 Pipe 3 Hydrograph AR amp R 2 year 1 hour storm average 29 4 mm h Zone 1 gt O a E g o e a m File Edit Properties Worst case minor storm 7 0 3 TIa I TT 62 01 0 25 60 73 _ l L 2 0 2 z E O O J E 2 0 15 2 v o 56 300 0 1 55 644 E 0 05 55 325 L 54 969 Length 42 metres Diameter 675 mm Pit 4 0 20 40 60 80 100 1 Pipe Slope 5 45 Pond RL 56 432 Time mins Qmax 0 289 cu m s Vmax 4 49 to 1 51 m s SS 3 Pit 3 HGL AR amp
54. and procedures with a semi theoretical basis These procedures have been included in a comprehensive generic pit capacity spreadsheet available to DRAINS users and the on grade pit procedures have been incorporated into DRAINS via wizards located in the Pit Data base opened from the Project menu For the gutter and pit shown in Figure 5 22 the on grade procedure shown in Figure 5 23 applies Gutter Width Gutter Face Slope degrees eee Road Crossfall Pa V NT Gutter Crossfall N Gutter Crossfall at N Edge of Road Lip of Gutter Figure 5 22 Road and Pit Characteristics Flow is assumed to approach a pit along a gutter At the pit the gutter crossfall may become steeper to provide a depression The pit may be a kerb inlet a grate or a combination inlet with both The latter kerb inlet is assumed to project beyond the grate so that the approaching flow encounters this first The method requires information on the road cross section as well as on the inlet characteristics The grate types detailed in the HEC22 manual are shown in Figure 5 24 DRAINS User Manual 5 28 November 2014 HEC22 Inlet Capacity Wizare Pit Properties General On Grade Data vag Data Inlet Capacity Gin vs Approach How Qa Paste Data Copy Data HEC Wizard i Woo mouara OOLLETT ir L nities De Tiem an PDT Reticuline L giin Te 121 Sem 4 Tod Trem fa Cie Aid
55. applied by relatively inexperienced designers Open channel calculations may require knowledgeable interpretation and any modelling of large or critical systems should be done by experienced engineers DRAINS models allow flows to be reversed for example when high water levels or pressures in a pipeline force water back through side branches This may not be obvious from the initial display of peak flows because DRAINS only displays the peak positive pipe flowrate so it will be necessary to explore results and property sheets Both DRAINS hydraulic models can sometimes display instabilities rapidly fluctuating water surfaces or spikes sudden rises and falls in water level and flowrates These are typically caused by overshooting of interpolation and extrapolation calculations and can usually be ignored after checking the model If instabilities are present in any models submitted to a reviewer explanations or interpretations should also be provided indicating that these will not invalidate the results DRAINS User Manual A 20 November 2014 TT 26 at 28 29 30 31 a2 33 A 5 Checking Model Components Flowrates and Water Levels A 5 1 Viewing Pipe System Components Components can be inspected by opening property sheets Figure A 15 property balloons Figure A 16 or transferring data to a spreadsheet via the Windows Clipboard using options in the Edit menu Figure A 17 The spreadsheet data output is the only easy way of detecti
56. be derived or by dividing the k derived for a stand alone model by for the new model multiplied by for the original RORB model Since DRAINS does not reveal the lengths to outlets it will be easiest to determine a new k by trial and error matching the peak flowrates defined by the original model For sub catchment routing RAFTS uses the equation S BX IBFL PERN 0 285 A 14U S99 Q97 Equation 5 13 DRAINS User Manual 5 20 November 2014 where BX is a calibration factor similar to RORB s kg IBFL is a factor for modelling overbank flow PERN is a factor that adjusts the catchment routing factor to allow for catchment roughness A is the sub catchment area km U is the fraction of the catchment that is urbanized and S is the main drainage slope of the sub catchment For routing along stream reaches RAFTS applies a translation over a nominated time or performs Muskingum Cunge routing based on the stream cross section and roughness For sub catchments WBNM uses the routing equation S 60 PA 10 Equation 5 14 where LP is a lag parameter and A is catchment area ha Values of the WBNM lag parameter are typically between 1 3 and 1 8 This can be used to calibrate the model in a similar way to the RORB parameter ke WBNM2003 also allows for translation and Muskingum routing in stream reaches For stream reaches a similar equation is used S 0 6 60 LP A Q Equation 5 15
57. be used as a valid analysis procedure but the ILSAX hydrology is a more accurate and proved hydrological procedure Analyses should be carried out using the unsteady standard and premium hydraulic model calculations These are superior to the basic hydraulic model in the following respects e They are more soundly based on theory including all the terms of the St Venant equations of mass and momentum conservation see Section 5 6 4 so that they can model sub and supercritical flows in pipes channels and with the premium hydraulic model overflow routes e They are more stable and will give more accurate results for pipe and open channel flows e The premium model permits modelling of overflows and other configurations that are not possible in the basic model For example it is possible to model two or more outflows from a sag or on grade pit or anode Situations such as flows spilling from a street gutter or channel into a driveway or across a road centreline can be modelled in this way e The premium model can model situations where on grade pits are submerged by water ponding over adjacent sag pits with the on grade pit operating as a sag pit while it is submerged e The premium model provides greater allowance for storage in surface flow systems such as ponded water over sag pits and surface flows between these leading to generally lower flowrates With the availability of multi core processing running times for the standard a
58. can enter data directly using the keyboard and mouse or open or import an existing file from the File menu If you are entering an entirely new system you must follow the steps that are explained in detail in the following section 1 2 Examples of DRAINS in Operation 1 2 1 Running a Model of a Simple Pipe System This example illustrates how a pipe system assumed to be located at Orange New South Wales can be set up in DRAINS and how design and analysis runs can be made You will learn best by constructing the model in the demonstration or full versions of DRAINS using the instructions set out below Alternatively you can inspect and run the finished model files Orange1 drn and Orange2 drn provided in the set of examples accompanying this manual The instructions do not cover all DRAINS options or procedures but are adequate to set up this model DRAINS User Manual 1 5 November 2014 Untitled DRAINS File Edit View Draw Run Help Oi elG Hydrological Models Rainfall Data Options Description Toolbar Pipe Data Base Pit Data Base Overflow Route Data Base Default Data Base Mm Drop Down Menu Main Window Drainage Systems are drawn here Figure 1 4 The Main DRAINS Window with the Project Menu Selected a Defining Hydrological Models Rainfall Data and Other Options The hydrological model rainfall patterns and component data bases should be established first Most of this infor
59. change the default data base at any later time Figure 1 13 Dialog Box Selecting a Data Base for Pipes Pita and Overflow Routes b Defining the Drainage System Suppose that the system to be designed is that shown in Figure 1 14 2 4 5 3 gt Fall of Land Figure 1 14 A Simple Drainage System DRAINS User Manual 1 10 November 2014 This system can be drawn in the Main Window using five tools from the Toolbar As you guide your mouse arrow over the Toolbar items tool tips will appear indicating the purpose of each button Once you click one of the Toolbar button the cursor will change to a pencil which can be used to place that component in the Main Window You can use the pit and node tools m and el to draw five drainage pits and three outlet nodes in the Main Window as shown in Figure 1 15 3 Untitled DRAINS balak File Edit Project View Draw Run Help Dlsjw S clelals B elun ee 9 ale Nodes at Pipe and Overflow Outlets 4 mW p For Help press F1 Figure 1 15 Initial Drawing of Drainage System eee ees Note that the overflow paths RA can be drawn as a polyline k allowing them to be placed to the side in cases where both the pipe and any overflows travel to the same destination Points along the overflow route are selected using the left mouse button and the end point is defined by clicking the right m
60. components that are likely to be used in your model If you work in only one geographical area always with the same hydrological model and set of storms this file need not change In this case when you first use DRAINS you should set up the storms and hydrological model for your area set up the pipe pit and overflow route data bases then save the file as a template or base that can be used whenever you begin a new project in the area This file should not DRAINS User Manual 2 38 November 2014 contain pipes or other components If you work in different locations you will need to set up a different template file for each geographical area Another way to set up a file with required data bases is to open a DRAINS file with the data bases that are required and then close this The drainage system disappears hydrological model and data bases remain The data for pits pipes and overflow routes can be changed using the Project gt Default Data Base option and editing the entries You can then copy this file as a template file and start a new job with a different filename 2 4 3 Hydrological Models The set ups for ILSAX the rational method and storage routing hydrological models are described in Chapter 1 DRAINS is structured to deal with two categories of hydrological model e ILSAX extended rational method and storage routing models that produce hydrographs developing a time series of flowrates and e rational method models tha
61. data and results are set out in formats similar to the ARR87 calculations their purpose is to display significant results from the computer calculations rather than to implement or show any specific calculations DRAINS User Manual A 5 November 2014 Design procedures consider surface flows as well as the flows through the pipe system with the main objectives being e preventing flows in street gutters or channels from being too wide 2 to 2 5 m or deep kerb height e keeping velocity x depth products below a limit typically 0 4 m s for pedestrian and vehicle safety e ensuring that flow levels do not come within a freeboard limit of habitable floor levels in adjoining buildings generally 0 30 to 0 50 m and e within pits allowing an appropriate freeboard between the pit water level and the surface generally 0 15 m to ensure that flows can easily enter pits The ways that these can be inspected in DRAINS are described in Section 5 Names of pits and pipes should follow a systematic pattern with each component having a unique name The names used in DRAINS and those displayed on drawings should be consistent A 3 5 Trunk Drainage Systems Runoff from individual pipe systems is collected in open channels located in dedicated flow path or stream corridors Designs are developed by setting up possible systems in a computer model such as HEC RAS or DRAINS and then running the model to obtain a satisfactory profile at a design aver
62. design around existing services or utilities and can allow for surface levels all the way along a pipe if suitable survey data is provided in the Pipe property sheet However the solution provided may set pipe inverts too deep so that it will be necessary to make adjustments by hand It may be necessary to use stronger pipe classes with greater wall thicknesses multiple pipes or box section conduits to reduce the cover requirements In complex cases relocation of existing stormwater pipes or other services may be the best solution Because re developments usually involve an increase in the density of development and the percentage of impervious area several drainage authorities have imposed on site stormwater detention OSD requirements These have become an important and often complicated issue for designers The Upper Parramatta River Catchment Trust has been the most influential developer of OSD design procedures in New South Wales introducing requirements such as a permissible site discharge PSD in L s ha of catchment and site storage requirement SSR in m ha DRAINS models detention basins by simulation presenting several relationships such as storage vs time upstream and downstream water levels vs time and inflow and outflow hydrographs It can also handle multiple outlets infiltration into soils and pumped systems The high early discharge HED system can also be modelled Details are given in Section 2 3 7 The detenti
63. do this some things to keep in mind are e You should not make any pipe smaller than the biggest pipe upstream i e if you have a run of say 1200 mm pipes you could try to downsize the one furthest upstream If you can y downsize this you will not be able to downsize any pipes in the run e For major storms you should use the same freeboard criterion as set in Project gt Options If you want to relax this criterion for major storms you should also relax it in Project Options prior to a design run in DRAINS The selection of invert levels is mainly based on allowable cover depths and slope restrictions The aim is to keep the pipe as shallow as possible and pipe sizes are increased where necessary to achieve this In cases where pipes need to be set deep enough to pass under other services such as water supply pipes increased cover depths can be defined in the Project Options property sheet effectively specifying a minimum pipe depth DRAINS User Manual 4 8 November 2014 Allowance is made for cover depths at intermediate levels along a pipeline as defined in the Survey Data property sheet called from a Pipe property sheet see Section 2 3 4 A result is shown graphically in Figure 4 6 This output also shows a pit with a significant drop which might be a consequence of aiming to keep the pipe system as shallow as possible If you wish to grade the upstream pipe down to the pit it will be necessary to adjust the invert leve
64. established models were made available in DRAINS to model rural or largely rural catchments The time area procedure used by ILSAX has not been calibrated to rural catchment data while the other three have been extensively tested and used in rural environments and are supported in Australian Rainfall and Runoff 1987 The emulations of the models will give similar answers to the original RORB RAFTS and WBNM models but there may be differences in flowrates due to different computational procedures and the many different features in the operation of these models For example the RAFTS model in DRAINS is simpler and has less features that the xprafts program provided by xpsoftware Designers and reviewers will need to ensure that the correct parameters for a location are applied These may come from published relationships such as those in Chapter 9 of ARR87 Book 5 Section 3 of the 1998 version or by calibrating the storage routing model to rural model peak flow estimates from Chapter 5 of ARR87 Book 4 Section 1 in the 1998 version DRAINS User Manual A 17 November 2014 Table A 12 Comparison of Flowrates and Volumes Generated by Port Adelaide Pipe System Models Hydrological Model Sub ILSAX with Soil Type of 2 and AMC of ERM with Catchment Rational Separate Separate Total 1 2 3 4 Method ARR87 areas areas Storms Synthetic Synthetic 5 Year ARI Flowrates m s 100 Year ARI Flowrates m s 5 Year ARI Runoff Volumes from
65. following inputs e apit name of up to 10 characters including blanks e asurface elevation m This can be arbitrary but it is recommended that you work with a standard datum such as Australian Height Datum AHD e apit family and size defined using drop down lists linked to inlet capacity information set up in the Pit Data Base as described in Section 2 4 6 A pit type must be established in the Pit Data Base for all the pit families used e a dimensionless pit pressure change coefficient for full pipe flow which defines the change in the hydraulic grade line HGL at a pit due to turbulence and other effects Pit pressure changes are explained in Section 0 and DRAINS offers methods for automatically calculating these Some typical values are presented in Table 2 1 DRAINS User Manual 2 4 November 2014 Drainage Pit Pit Properties a UDM This is E o Baseflow Inflow Hydrograph Name Pit C2 Surface Hew m 705 8 Pit Family Qld DMR Gully Pit both 0 25 2 grade Pit Size 5 Lintel Fressure loss coefficient o5 Ku for full pipe flow Pit has bolt down impermeable lid This pit is Blocking Factor Oto 1 0 0 unblocked f New can be designed f Use defaut value of 0 C Existing cannot be designed You specify Notes Figure 2 3 Drainage Pit Property Sheet for an On Grade Pit First Page Table 2 1 Approximate Pit Pressure Change Coefficients k Pit with a straight through flo
66. from ARR87 is the definitive form of information for general design b Hydrograph Methods DRAINS makes rainfall information available through procedures set out in its Project menu The rainfall data is the same for all the hydrological models in DRAINS ILSAX Extended Rational Method RORB RAFTS and WBNM except the rational method For the Gymea model introduced in Section 2 which uses the ILSAX model the Rainfall Data option opens the window shown in Figure A 5 This displays a design storm pattern or hyetograph taken from ARR87 which is included in a rainfall data base Many storms can be included in this base and selected as Minor and Major storms for design calculations The intensities used can be viewed and checked against intensity frequency duration I F D charts included in council documents or obtained from the Commonwealth Bureau of Meteorology The rainfall patterns selected for a run can be reviewed by looking at the Select Major Storms and Select Minor Storms options in the Project menu as shown in Figure A 6 In the Gymea example only two storms are considered but designers would normally use 4 to 8 patterns with durations covering the range where the highest peak flows occur Generally shorter storm durations produce the highest flows in small catchments but as catchment size increases the critical duration also increases Thus designers might use durations up to 1 or 2 hours for piped drainage systems and durati
67. have been specified e the components of a system are joined correctly e the drainage system components have been fully specified The run options in the menu are greyed out if these conditions are not met Once a run begins DRAINS sorts through the various components to define linkages throughout the system and the order in which calculations should occur Using the coordinates of the objects it identifies connections between pits or nodes and links such as pipes or channels where the positions of the ends of a link are within the symbol of a node in the Main Window The connections between pits and sub catchments are established where the symbols overlap The pits or nodes at the extremities of drainage systems are identified as those having no incoming links DRAINS also checks inputs for any inconsistencies that have escaped the checks in property sheets during data entry 4 2 6 Hydrological Calculations With the ILSAX model hydrological calculations involve the computation of the hydrographs from the paved and grassed surfaces of each sub catchment using the Horton loss model and the time area routing methods described in Section 5 3 2 b They are carried out in the same way for both Design and Analysis runs With the extended rational method and the storage routing models hydrographs are calculated by different procedures The rational method procedure only calculates peak flowrates In calculated hydrographs flowrates are defined at
68. high swelling potential There is a third parameter affecting the infiltration into soils that appears in the rainfall data base The antecedent moisture condition AMC is a number with the same range as the soil type 1 to 4 that indicates the wetness of the soil in the sub catchment This is specified for individual storm patterns in the Rainfall Data sheet shown in Figure A 5 The flowrates calculated by DRAINS are sensitive to the AMC selected The lower the AMC the higher the infiltration loss into the soil will be and the lower the runoff The following table is used to set an AMC based on the expected rainfall in the 5 days prior to a storm Table A 8 Antecedent Moisture Conditions Description Total rainfall in 5 days preceding the storm mm 2 Rather dry 0 to 12 5 Rather wet 12 5 to 25 In a design situation the AMC should reflect the expected conditions prior to a representative future rainfall event This can be determined by examining records of previous rainfalls near the site For example daily rainfalls can be ranked and the 5 day rainfalls prior to the largest rainfall events can be identified Examples for two locations are shown Figure A 10 In Section A 4 4 the large variability of model results with AMC is demonstrated Similar variations can occur with different soil types Reviewers need to be satisfied that the parameters selected reflect the soil types and wetness occurring at the project site An issue t
69. hydrological losses to be varied across the catchment area reflecting various soil types Since these models are essentially networks of storages detention basins and reservoirs can be easily incorporated RORB RAFTS and WBNM belong to a class of models termed runoff routing models which also includes models based on unit hydrograph and kinematic wave calculations Runoff routing models can route a hydrograph from one geographical location to another allowing for changes such as translation and attenuation of the hydrograph as shown in Figure 5 17 Hydrograph at Hyd hat iuit sta t of travel start of a reach Hydrograph at an end of the reach Routed Hydrograph at end of travel Flowrate Flowrate m s m s Time minutes Time minutes Figure 5 17 Translation and Attenuation Effects on Hydrographs DRAINS User Manual 5 19 November 2014 The basic non linear model used in Australian storage routing models was developed by Eric Laurenson RORB a practical computer application of this model was produced by Eric Laurenson Russell Mein and Tom McMahon at Monash University Melbourne in the mid 1970s At the same time the RSWM Regional Stormwater Model was developed by Allan Goyen of Willing amp Partners and Tony Aitken of SMEC These models were immediately popular as they filled a need for modelling mixed rural and urban catchments allowing for soil and rainfall variability and providing flow estimates at po
70. ie ee Peete a m Pies Depa bia mi hapi ies Dees Pies Mn Te Bpr men e Fi fis Des bea Pedri Peai P PS Beek po basa Binu lien ar Paa lapi mare megia i Sa pi ang ie ea rs are tee has Hy ion hn Frisa Fipa ee cts Pa ap ro ha oo Co ETA pn om re mes aa Py a CADE S rut t r miea Piped Dean Kiadel Piaron k oepa Mode Mem ri ee 1 E lome Inia p Laimi li I Dia l kehi hs hal i m arias asi Ass fe NOTES K ki Ma H 0 E e R 5 T u i 9 Runoff mperviouw Pervious I oe 10 Volume tuno VoRunolf Vol il he ames fh im im im Ta 12 E 13 4 15 89 65 98 87 98 17 91 3 SS CL A SE a 14 9 37 92 66 14 88 93 24 96 2 Bectereicas E imme 15 35 02 93 5 83 89 29 18 97 9 ai phe rink cai een ace oD 16 So oe yh oe 17 INLET DESIGN FIFE SYE a aaa E eee 18 real ay darai Danaja n aaar aaiae pada da peal cH 2 ee S ae tS E a Pn mA i o PE aaea i aa GA 20 Peak Sub Critical Flaw Fath Total Overflow Peak erat tes Ta Wee hing en ego a ae e aT 21 Zatcthm en Origin of Flow Depth x Inlet Inlet Approach Bypass Flow Depths Flow in text J 22 Flowrate Approach Flowrate Width Velocity Family Size Flow Flow Width Velocity Pipe 23 imas Flaws mis drm imtis imie mele dim m ie inie 244 orst storm 25 0 25 Sutherlanc kerb inleaty 0 25 0 a i 0 225 26 zi 28 4 041 0 164 13 0 03 0 245 29 30 31 0 033 Pit 4 1 0 0 0 Sutherlane kerb inlety 0 033 0 006 1 26 0 08 0 24 J2 33 4 0 052 Fit A i 0 164 13 0 03 0 216 0 144 2 73
71. in the Project menu which appears as shown in Figure A 14 Runoff routing model can be run together with an ILSAX model in DRAINS This is convenient where the tailwater affecting a small urban drainage system is created by flows from a larger urban rural catchment A number of storm events can be modelled without having to transfer data and results between models Further information on the DRAINS implementation of these models is provided in the DRAINS Manual and the Help system The models and their results can be inspected using the Viewer in the same way as the ILSAX and rational method models DRAINS User Manual A 16 November 2014 Table A 11 Comparison of Flowrates and Volumes Generated by Manly Queensland Pipe System Models Hydrological Model Sub ILSAX with Soil Type of 3 and AMC of ERM with Catchment Rational Separate Separate Total 1 2 3 4 Method ARR87 areas areas Storms Synthetic Synthetic 5 Year ARI Flowrates m s Cat A 0 209 Cat A 2 0 034 Cat A 3 0 026 Cat A 4 Cat B 1 0 171 Cat C 1 0 136 100 Year ARI Flowrates m s Cat A 1 0 416 Cat A 2 0 066 Cat A 3 0 050 Cat A 4 0 163 Cat B 1 0 330 Cat C 1 0 261 5 Year ARI Runoff Volumes from the Whole Catchment of Rainfall Design storm sme 38 a ot 75 25 minute 46 60 63 smm ee 100 Year ARI Runoff Volumes from the Whole Catchment of Rainfall ame 63 a 85 Casu n 78 65 swe These three
72. in the Project menu which opens the property sheet shown in Figure 3 24 Comments and lines for the title block can be entered If no block is required the three TITLE BLOCK lines can be made blank f Removing Items from View Facilities like the Status Bar at the bottom of the Main Window and components such as sub catchments can be removed from the window if desired using the options in the central part of the View menu Toowoomba Example Pipe and Channel System Comments This is a hypothetical example developed to illustrate points in the DRAINS User Manual 2011 caret He Figure 3 24 The Description Property Sheet g Changes to the Main Window Coverage The Drawing Area can be extended at the four corners cropped reduced selectively or trimmed all round using options in the View menu Extend Drawing Area Crop Drawing Area and Trim Drawing Edges h Pop Up Menu Displays The pop up menus opened by right clicking on an object are the main means of presenting results of calculations on screen They also provide some information prior to calculations Two displays from the Toowoomba example are shown in Figure 3 25 3 4 Run Options 3 4 1 Design and Analysis Runs In the Run menu shown in Figure 3 26 there are at least three run options a the Analyse major storms standard hydraulic model b the Analyse minor storms standard hydraulic model c the Design option DRAINS User Manual 3 16
73. levels and flow characteristics during large storm events Some additional data is required for premium hydraulic model calculations This is revealed when you attempt to run an existing model such as the Orange2 drn with premium model calculations using the second or third options in the Run menu in Figure 1 27 For each overflow route a route length must be specified in addition to the travel time in the Overflow Route property sheet as shown in Figure 1 44 Figure 1 44 also shows the entry of required invert levels at the beginning and end of the overflow route You can enter this yourself or allow DRAINS to provide values at the start of a run checking these later The remaining issue is to specify outlet controls at sag pits These are usually weirs representing barriers such as road crowns or centrelines Only one sag pit occurs in the Orange2 premium Drn model and the control will be modelled as a parabolic weir as shown in Figure 1 45 In Step b of the process of setting up a DRAINS model the other data for pits pipes overflow routes and nodes is entered in the same way as for runs using the ILSAX hydrological model DRAINS User Manual 1 26 November 2014 Overflow Route OF 1 Basic Data Cross Section Data Name OF 1 Travel Time mins 0 1 Reach Length im 11 Scale off Length Extra Data for Premium Hydraulic Model Upstream IL m 22 5 Downstream IL m 22 3 Figure 1 44 Overflow Route Property Sheet
74. links Appending a DB1 data base Approach flows ARI e Overview of DRAINS ARR87 rainfall pattems e Recently added features Australian practice Australian Rainfall amp Runoff e How to apply DRAINS Australian standard 3500 3 Australian Standard Rational Method proced Autodesk Land Desktop e Parts of DRAINS Average recurrence interval e The methods used ee dr nar cai For quick reference you can use the index to the left entering a keyword or searching for the topic that you require Bolt down pit Bridge drawing tool lf this Help window is too small to view some of the illustrations enlarge it to see the complete topic Bridge property sheet Bridges Brisbane City Council design outputs January 2011 Bypass flows C mam Figure 3 63 A Typical HTML Help Message Within particular Help topics the underlined links open additional topics The index can also be used to find specific topics With well over 200 topics the DRAINS Help system provides a comprehensive guide to the program and a glossary of urban stormwater drainage terms and concepts It complements the material in this manual and provides timely advice on enhancements to DRAINS DRAINS User Manual 3 38 November 2014 4 OPERATIONS 4 1 Introduction This chapter outlines how DRAINS works and how to perform design and analysis tasks The detailed procedures within the program cannot be explained in simple terms so only a general description i
75. loss different from the loss of 0 0 No of identical parallel pipes P 1 assumed by DRAINS If an orifice outlet is selected the property sheet takes the form shown in Figure 2 34 You must supply a diameter mm for a circular orifice and the elevation of its centre The check box labelled High Early Discharge allows the modelling of a high early discharge pit a special type of OSD system You must provide a crest level and length for an internal weir that is a feature of this kind of storage Further details of these options are given in Section 5 8 3 The pit sump outlet type may apply in situations where basins are created unintentionally by the creation of a barrier such as a road embankment If this outlet type is selected the outlet changes to that shown in Figure 2 35 A pit family and size is to be selected using the same drop down list box as in the Drainage Pit property sheet Since this type of outlet is prone to instabilities in calculations where there are incoming pipes that are below the surface of the basin it is usually necessary to locate the basin off line connecting to a sealed pit through a large artificial pipe with a capacity well in excess of the inlet An arrangement of this type is shown in Figure 2 36 Surface overflows are directed to the basin and the main overflow comes out of it The pipe leaving a basin is specified in the same way as a normal pipe If this is rectangular it may be necessary to set up a s
76. m s e the blue numbers are the greatest flowrates in each pipe in m s e the red numbers are the greatest overflows from pits in m s in the standard hydraulics model or the flowrates at the centre of an overflow path in the premium hydraulic model which will include any flows from the downstream sub catchment e the green numbers are the highest levels reached by the hydraulic grade lines HGLs throughout the pipe system in m elevation defining the highest water levels during the 2 year ARI 25 minute storm event considered At sag pits the highest surface ponding level is also shown Since it calculates conditions at a number of time intervals DRAINS produces hydrographs or time series of runoff flowrates from the rainfall hyetographs It is possible to view what happens at all times during the storm event as shown in Figure 1 32 a Reviewing Results You can now inspect the results and check the pipe inverts and sizes determined by DRAINS There are a number of ways of doing this the most comprehensive being the transfer of information to a spreadsheet using options within the Edit menu The data spreadsheet for the Orange Example is shown in Figure 1 33 Results of particular runs of DRAINS can also be exported to worksheets using the Edit menu as shown in Figure 1 34 These can be for example minor and major storm results from design procedures The major minor system is usually employed in Australian drainage design
77. m sec by this channel Madmum flow 1 037 cums 1 Comesponding velocity 1 52 m s Maxdmum depth 0 233m UNSAFE Calc Slope Maximum flow width 6 40 m Maximum D x V 0 35 sq m sec Cancel Help Figure 4 8 The Overflow Route Property Sheet Channel slope Having established safe flows for each flow path the method then determines the pit and pipe sizes needed to restrict the surface overflows to the safe limits considering both minor and major flows DRAINS User Manual 4 10 November 2014 This process requires that pit types be classified into families and sizes in a similar way to the classification of pipe types and diameters With the user having defined the pit and pipe types required DRAINS searches through the available sizes to determine the required ones at each overflow location It also selects pipe sizes so that at a major storm level such as the 100 year ARI storm event HGL levels at pits are still below the ground surface This ensures that the drainage system does not completely fill with water and the pipe flows will be maintained even when stormwater ponds over pits In some cases DRAINS cannot arrive at a solution that meets the safety requirements most obviously when the flow from a sub catchment is much larger than the capacity of any of the pits that can be selected DRAINS returns the notice in Figure 4 9 advising that the pipe system must be changed or that different pits are required
78. manually overwritten 3 4 5 Quantities Notes The Quantities option in the Run menu displays or prints out a table of quantities for the pipes in the current system as shown in Figure 3 33 This complements the information printed for each completely defined pipe at the bottom of its property sheet as shown in QUANTITIES Excavation volume 30 4 cu m Rock volume M A DRAINS calculates excavation volumes from pipe lengths and Length of trench deeper than 1 2m 17 2 m invert levels assuming the trench widths given in Table 3 1 at an average depth of 1 5 m Table 3 1 with 200 mm and the diameter being added for each additional parallel pipe The bedding depth is assumed to be Figure 3 32 Quantities Information 50 mm below the outside of the pipe wall in Pipe Property Sheet DRAINS User Manual 3 21 November 2014 SUMMARY OF QUANTITIES Length m Material 119 Concrete under roads Total Excavation Volume 210 0 cum 119 metres of trench deeper than 1 2 metres with an average depth of 1 53 metres DETAILED QUANTITIES Dia Length Excn Length Avg Material Wol Lem depth 1 2m 19 1 oot 19 1 1 53 Concrete under roads foo 7 2 30 4 Vite 1 53 Concrete under roads foo 4 IPSS Concrete under roads 750 fuel 1 53 Concrete under roads 63 8 152 Concrete under roads Figure 3 33 The Summary of Quantities Table 3 1 Default Trench Width Table Diameter 750 mm 3 5 Output Options 3 5 1 Transfers of Displays
79. method from Australian Rainfall and Runoff institution of Engineers Australia 1987 is fully explained in that publication C1 values must be entered for impervious and pervious areas These are 10 year average recurrence interval ARI runoff coefficients that are adjusted for other ARIs by multiplying the C1 values by the frequency factors shown in Table 5 10 The value for the impervious area is always 0 9 DRAINS User Manual 5 17 November 2014 Table 5 10 Rational Method Frequency Factors ARI years Frequency Factor a ee The pervious area runoff coefficient is calculated from the formula Cio 0 1 0 0133 l 25 _ Equation 5 10 with upper and lower values of 0 1 and 0 7 l is the 10 year ARI 1 hour rainfall intensity used as an index of the rainfall climate The third method is taken from the Australian New Zealand Standard AS NZS 3500 3 2 This gives different procedures for Australia and New Zealand and only the Australian procedure is implemented in DRAINS at present In the Rational Method Model property sheet this option requires that only the 10 year ARI 1 hour rainfall intensity 101 be entered This is used to determine the pervious area C value using the above equation This runoff coefficient is adjusted upwards by 0 1 for clay soils and downwards by 0 1 for sandy soils The frequency factors from Table 5 10 are applied with a factor of 1 25 being used for ARIs greater than 100 years The runoff coe
80. mrs Omas 0 102 cu m s Ymax 1 44 m s Figure 1 37 Long Section Display for a Pipe showing 2 Year and 100 Year ARI Results The pipe design is performed on the basis of the allowable flow along the overflow route The method determines this flowrate taking into account the flows from of the sub catchment immediately downstream of each pit It then works backwards to define a set of pit inlets and pipe sizes that will limit overland flows to safe levels in both minor and major storms Safety requirements are defined in terms of flow depths and velocity depth products in the Overflow Route Data Base as shown in Figure 1 26 1 2 2 Running the Rational Method and Extended Rational Method Models To illustrate the rational method procedure the same Orange system can be modelled using a rational method hydrological model in the file named Orange2Rat drn You can run this if your hardware lock is enabled to run the rational method or if you are using the DEMO version This file can be created in the same way as the ILSAX model but it is also possible to adapt the model to run with the rational method procedures Only three of the property sheets for data entry differ from those DRAINS User Manual 1 23 November 2014 for the ILSAX hydrological model In the setting up of project options the Hydrological Model for a rational method model called from the dialog box in Figure 1 5 takes the form shown in Figure 1 38 Default Model for Design and
81. must be followed by analysis runs using the same design storms to simulate and display the performance of the system in detail The designer can than assess whether this is satisfactory and make further changes and re runs to refine the system 5 6 3 Basic Hydraulic Calculations In DRAINS the now obsolete basic hydraulic model provided a conservative procedure for tracing hydraulic grade lines through drainage systems working upwards from tailwater levels at the outlet at each calculation time step At each time step in an analysis this model made a pass downwards through the drainage system determining flows into pits possible bypass flows and the flows along pipes It then retraced this path from a specified tailwater level at the system s outfall determining hydraulic grade lines and water levels in pits Allowance was made for pipe friction and pit pressure changes and both part full and full pipe flows were modelled The possibility of water upwelling from pits due to the flow capacity of the downstream pipe system being exceeded was also considered With this model DRAINS used a hydraulic engine from the PIPES program to model pressurised flows It switched to this when pipes surcharged going from part full to full pipe flow and handled the complex timing and flow volume transitions involved in transferring between calculation methods 5 6 4 Unsteady Flow Calculations in Standard and Premium Hydraulic Models As noted in Section 4 2 7
82. of pipes pits and catchments leading to each pit should be other features displayed with their areas and possibly land uses Pipe long sections Long sections exported from DRAINS can be used Plans and sections of any special pits junctions or chambers Drainage calculations These are usually set out in tables following examples in Australian Rainfall and Runoff 1987 and other manuals DRAINS provides comprehensive tabular results DRAINS also produces a plan drawing of the design model Table of quantities Pit schedule A table from DRAINS may be presented Street drainage systems are commonly designed with the major minor system for minor ARIs from 5 to 20 year ARI with 2 year ARI applied in some tropical areas where rainfalls are very high Most design methods also include a check for fail safe behaviour in major rainfalls usually at 100 year ARI Most calculation software is based on the rational method procedures in Australian Rainfall and Runoff 1987 ARR87 which was developed before use of spreadsheets became common and most calculations were made by hand The formats of calculations sheets associated with later manuals such as the Queensland Urban Drainage Manual QUDM have followed this model DRAINS relies on computer computations that go significantly beyond earlier hand calculations and its tabular outputs do not reproduce simple calculations such as the multiplication of numbers set out in columns While DRAINS
83. of this type of manipulation is the use of detention basins to simulate stormwater infiltration systems or pumps as noted in Section 2 3 7 The following sections describe the features of each component starting with those that you are likely to use most frequently 2 3 2 Pits a General Pits like other forms of node act as entry points for water into the pipe system They can represent a street gully pit a manhole a junction a flow diversion or other components On grade pits are located on slopes while sag pits are in hollows or depressions as shown in Figure 2 2 When stormwater runoff reaches an on grade pit at smaller flowrates all flows are collected As approach flowrates increase a point is reached where some bypass flow occurs This will flow away from the pit perhaps to another pit downstream with additional flows joining it along the way To model on grade pits a relationship between the approach flow and the flow captured by the pit must be specified These cannot be established by theory and are usually determined from modelling studies or tests on installed pits as is discussed further in Section 5 5 On Grade Pit located on a slope Sag Pit located in a low point e a eee eee ees as Figure 2 2 On Grade and Sag Pits b On Grade Pits The Drainage Pit property sheet can take two forms depending on the type of pit selected The on grade pit property sheet shown in Figure 2 3 requires the
84. of this manual Refer to the index for the locations of these 2 2 2 The File Menu This menu controls most ways of inputting and outputting data The functions of creating new files opening and closing stored files saving and saving as files and exiting are carried out using standard Windows procedures Through the additional menus shown below called through the Import gt and Export options in the File menu information can be taken in and out of DRAINS in various file formats which are covered in detail in Chapters 3 and 5 DRAINS User Manual 2 1 November 2014 Edit Project View Draw Run Help Save Ctrl 5 Print Diagram Ctrl P 1 Toowoomba Estate drn 2 Toowoomba Addition drn 3 Gymea Piped Drain Example drn 4 Bowen Channel amp Stream Example Unsteady drn Exit lf a DRAINS model already has a background the first option in the File Import option will be Import DXF background instead of Import DXF file in anew model This enables the background to be changed or updated 2 2 3 The Edit Menu This contains functions like Undo and Redo and Find facilities for locating components in large drainage networks The commands for transferring data and results to and from spreadsheets are also included here 2 2 4 The Project Menu This menu accesses information for the particular drainage system being analysed by DRAINS as well as the pipe pit and overflow route data bases It
85. option in the Project menu The spreadsheet results can also be stored and as is detailed in Chapter 3 it is also possible to transfer the results via a DXF file to drawing programs that can print plans and longitudinal cross sections of pipe systems Additional results from analysis runs are shown in Figure 1 37 DRAINS User Manual 1 22 November 2014 Overflow Route OF Basic Data Cross Section Data Shape ER road half section Safe Depths and How Rates Safe Depth for Major Storms m 03 fe i J f a H Use default values for this cross section SUT eee os C You specify Sate Depth x Velocity gq m sec 04 of downstream For Major Storms HL in m L Safe flow 1 190 cum sec by this channel Madmum flow 0 055 cums pT Comesponding velocity 0 90 m s Maximum depth 0 096 m Calc slope Maximum flow width 1 86 m Madmum Dx V 0 09 sq m sec cont Heb Figure 1 36 Overflow Route Property Sheet showing Flow Characteristics Channel slope Pipe 3 Maximum Flow and HGLs for the Selected Storm I a re 3 Maximum Flow and HGLs for the Selected Storr e re So AR BA 2 year 25 minutes storm average 40 2 mmh Zone 1 AR aR 100 year 25 minutes storm average mm h Zone g m Cover 60m Cover 0 0 0 60m Cover oe 2 nag M Length 27 6 metres Diameter 300 mm Length 27 6 metres Diameter 300 mm Pipe Slope 1 09 Pipe Slope 1 09 Omas 0 024 cums Wmas 1 37 to 0 60
86. other services to be defined so that DRAINS can avoid these allowing for a vertical clearance defined in the Options property sheet in the Project menu as shown below Minimum clearance 100 to services mm In Design runs DRAINS tries to locate pipes between services going under them if no other route is possible If this is unacceptable the designer can selectively remove services or make manual adjustments to the pipe cross section and or alignment The long section display in Figure 2 14 shows how the ground levels and service positions appear after a Design run is carried out using the Long Section option in the pop up menu for the pipe The position of the pipe is defined by the intermediate low point in the surface The pipe fits comfortably under the services shown in red and the required clearance shown in yellow Pipe 6 5 Maximum Flow and HGLs for the Se worst Case major storm Intermediate Survey Points on Surface 0 99m Cover 0 95m Cover 705 300 r 4 803 HESAN r04 266 a 704 152 FLERE ee 703 552 Pit B 5 Length 11 4 metres Diameter 600 mm Pit BA k Pipe Slope 1 00 Omas 0 570 cums Ymar 2 02 mrs Surface Ponding Level at a Sag Pit Figure 2 14 Pipe Long Section Display In some cases a non return device such as a flap gate may be installed in a pipe preventing flows from moving upstream This can be modelled by ticking the Include Non Return Valve box in the Pipe
87. percentage are required Sub Catchment Data Sub catchment name Cat Sub catchment area ha Imperious Area 4 of total Hydrological Model Default model You specify Cancel Customise Storms Help Figure 2 21 RORB Model Sub Catchment Property Sheet The sheet for a RAFTS sub catchment shown in Figure 2 22 requires more information In addition to catchment area and percentage impervious a sub catchment slope and a Manning s n for the pervious portion of the catchment are required to calculate hydrological losses and to define a routing parameter Sub Catchment Data Sub catchment name Cat A Sub catchment area ha Imperious Area 4 of total Hydrological Model i C Default model oub Catchment Slope 6 fe fou specify Manning s n Shepparton RAFTS Y OK Cancel Customise Storms Help Figure 2 22 RAFTS Model Sub Catchment Property Sheet DRAINS User Manual 2 15 November 2014 The property sheet for the Watershed Bounded Network Model WBNM shown in Figure 2 23 is the same as that for the RORB Model However routing does occur in WBNM sub catchments using equations based on the sub catchment area Sub Catchment Data ee Sub catchment name Cat Sub catchment area ha 476 Impervious Area 2s of total 0 Hydrological Model Default model f You specify Cancel Customise Storms Help Figure 2 23 WBNM Model Sub Catchment Property Sheet e Customising Storms
88. periodically save the file and tidy it up so that it looks like the arrangement in Figure 1 28 If you have Property Balloons switched on in the View menu details of the data for various components can be seen without opening property sheets a Running the Program You can now run the program in Design mode from the Run menu shown in Figure 1 27 After a Design run the message in Figure 1 29 appears advising that the process is complete and that you should run an analysis with minor or major storms to assess the results You can do this my choosing the Analyse minor storms and Analyse major storms options The standard hydraulic model is available in all DRAINS model The optional premium model requires more detailed information on overflow routes in order to model them with unsteady flow hydraulics DRAINS User Manual 1 18 November 2014 When performing an analysis DRAINS is likely to display the message shown in Figure 1 30 Run Help Analyse major storms standard hydraulic model Analyse minor storms standard hydraulic model Analyse major storms premium hydraulic model Analyse minor storms premium hydraulic model Design Revise Pit Loss Coefficients gt Quantities k Figure 1 27 Run Options ise Orange2 DRAINS Glej x J File Edit Project View Draw Run Help Disie 6 clam euo e ale Pit 5 on grade NSW RTA SA Inlet 3 crossfall 1 grade SA1 Type 2 1 longitudinal grade Ou
89. property sheet 2 3 5 Sub Catchments a ILSAX Model Sub Catchments The form of the property sheet for a sub catchment depends on the hydrological model defined in the Hydrological Models option in the Project menu as shown in Figure 1 4 and Figure 1 5 If an ILSAX type model is chosen the sub catchment can be divided into the paved grassed and supplementary land surface types illustrated in Figure 2 15 e paved area impervious areas directly connected to the drainage system e supplementary areas impervious areas not directly connected to the drainage system and e grassed areas pervious areas which can be lawn bare earth landscaped areas bushland porous pavement or any other pervious surface The supplementary area models any impervious surfaces that drain onto pervious or grassed areas where the runoff might be absorbed into the soil These could be sheds swimming pools parking lots DRAINS User Manual 2 11 November 2014 and other impervious areas that do not drain through pipes or over impervious surfaces to the sub catchment outlet In the original specification of these land uses in the ILLUDAS Model Terstriep and Stall 1974 defined them using the diagrams in Figure 2 16 These indicate that the supplementary area was used to model systems where downpipes discharged directly onto grassed areas Thus this feature can be used to model certain water sensitive urban design WSUD options N 1 4 H
90. rate over the of storage and at the end li 1 period DRAINS User Manual 5 37 November 2014 together with a relationship linking outflow rates with corresponding storages for various water levels in a reservoir or basin Reservoir routing procedures work on a finite difference step by step procedure working through the time periods from the start of a Known inflow hydrograph Conditions at the beginning of each time step are known and relationships are used to derive conditions at the end There are many ways of setting up these calculations both direct and iterative but the following way used in ILSAX is probably the simplest Equation 6 32 can be rearranged so that the known terms are placed on the left hand side LHS I la Qi 2S 2 Qiri 2 Si Equation 5 28 At At a Inflow values li li etc are known in advance and outflow Q and storage S at the beginning of each period are known Routing procedures estimate values for Qi and Si by various methods of graphical or numerical interpolation DRAINS applies this procedure at each time step but also allows for tailwater effects that might alter the elevation discharge or height outflow relationship A height storage outflow relationship can be developed from a aheight storage relation derived from contour information on the topography of the storage area b a height outflow relation constructed from the hydraulic relationships for the outlet structures
91. rise and fall patterns reflecting the simple design rainfall patterns that are commonly used However in complex or badly implemented pipe systems complex patterns such as the hydrograph shown in Figure 4 5 can occur A DRAINS plot may show frequent rises and falls at some times giving rise to black ink The plot also shows a flow peak that has caved in or reversed itself This can occur when the HGL at the pit upstream of a pipe overflows while the HGL at the pit at the downstream end is still below the ground surface As flowrates increase or tailwater levels rise higher the HGL level in the downstream pit rises flattening the HGL for the pipe and reducing the flowrate through it This produces the hollowed out effect The hydrograph in Figure 4 5 also displays negative flows indicating that there has been a flow reversal Flows can reverse in any DRAINS model if the HGL slope is negative but this occurs rarely In this case a high HGL downstream causes flows to run backwards These can also be sudden spikes and instabilities that occur at very low flows due to waves that are numerically generated Users should interpret plots with strange patterns to understand what is going on Often this requires inspection of two or more flow and HGL plots together DRAINS User Manual 4 7 November 2014 py Pipe C 1 Hydrograph AR amp R 100 year 25 minutes storm average 145 mm h Zone 1 File Edit Properties 0 12 ee T Flow
92. segments linked through simple nodes These segments can have different properties such as cross sections and slopes Two or more overflow routes can be connected to a node and their flows combined as shown later in Error Reference source not found DRAINS User Manual 2 21 November 2014 As described in the next section the overflow path from a detention basin acts as a high level outlet to the basin and requires additional information to an overflow from a pit this being set out on an additional page of the property sheet 2 3 7 Detention Basins DRAINS can incorporate large or small detention and retention basins into drainage networks To define a basin or storage fully at least two components are required The first is the basin which is defined in the Detention Basin property sheet an example of which is shown in Figure 2 32 This includes a basin name options to set an initial water level and infiltration characteristics an elevation surface area or elevation volume relationship and a low level outlet specification Detention Basin el Data Initial Water Level Infitration Data Name Basin zZ Bev Surf Area im sq m 461 5 0 5 461 75 2030 4s 25 9790 Low Level Outlet Type connecting to a pipe C Orifice Kentry Kbends C Pit Sump f Circular culvert C Rectangular culvert f None 5 2 3 4 5 6 Fi 8 Faste Table Note The pismoidal fomula is used to calculate volumes from suface areas
93. shown in Table 5 15 Table 5 15 Victorian VicRoads Pits Source VicRoads Manual Pit Kerb Inlet Comments Type Dimensions VicRoads 1 0 and 1 5 m 1 0 and 1 5m none side entry pits wide by 0 10 m deep VicRoads 1 m grated inlet Transverse grates A amp B pit 1 0 m wide x 0 75 1 0 1 5 2 0 or 2 5 m long VicRoads Grated side entry 1 0m wide x 0 1 assumed 1 0 mx 0 45 m pit m deep Queensland relationships are outlined in Table 5 16 Queensland has the most comprehensive data of any Australian state There has been an extensive revision of the original Queensland 2003 relationships because of the introduction of new pit types and relationships and new extrapolation procedures DRAINS User Manual 5 25 November 2014 Brisbane City Council Pits from BCC Standard Drawings Gold Coast City Council Pits from GCCC Manuals Max Q Drainway Plus from Max Q catalogue 2003 Max Q Stormway from Max Q catalogue 2003 Max Q Stormway catalogue Humes Drainway Pits obsolete BroPit obsolete DMR Field Single and 0 6 x 0 9 mor Inlet double 0 6 x 1 8 m South Australian relationships are provided in S M and L nominally 2400 3600 and 4800 mm lintel lengths As above 2TP X and 3TP X S1000 A S1600 A S2400 A S3600 A and S4800 A 31000 H Table 5 16 Queensland Pits 2008 Version Various sources see Column 1 Kerb Inlet Comments nian Dimensions lintels 2
94. the flow is supercritical it is nonsense to calculate a shock loss using the supercritical velocity _4 QUDM page 5 111 requires this so itis done here DRAINS uses a better procedure X 5 ii For pipes flowing part full with subcritical flow DRAINS does a backwater calculation within the pipe In the procedure used here a constant uniform depth is assumed gt 6 iii K values calculated here are taken from QUDM charts Some charts are dependent on submergence ie HGLs and the different HGLs calculated here Rants of Anabel Z can result in different K values to those used in DRAINS even if they were revised in DRAINS using the QUDM chart option i 8 9 10 Version 8 0 11 ARI 5 12 LOCATION TIME SUBCATCHMENT RUNOFF INLET DESIGN DRAIN 13 Structure Sub Tc I Imperviot Pervious Imperviot Pervious Area Equiv Qsub cat Origin QinK amp G WinK amp G DinK amp G VinK amp G DxV in K amp Inlet Qg Qbypass Tc 14 catchmen min mm h Cc C ha Area ha cu m s offlow cu m s m m m sec m2 sec type cu m s cu m s min 15 PitA 1 CatA 1 12 110 35 65 0 855 0 4845 0 772 0 474 0 145 Sutherlan 0 145 0 16 Pit A 2 Cat A 2 3 153 80 20 0 855 0 4845 0 08 0 062 0 027 Pit A 1 0 0 0 0 0 Sutherlan 0 015 0 1 17 Pit B 1 Cat B 1 8 130 55 45 0 855 0 4845 0 593 0 358 0 129 Pit A 2 0 023 1 04 0 068 0 93 0 06 Sutherlan 0 133 0 18 PitC 1 Cat C 1 6 144 60 40 0 855 0 4845 0 411 0 259 0 103 Sutherlan 0 059 0 044 19 Pit A 3 CatA 3 3 153 80 20 0 855 0 4
95. then delete it Components should connect properly The ends of links should be placed near the centre of nodes and sub catchments should clearly connect to pits and nodes Sub catchments must not be placed over pits or overflow routes over pipes as it will be difficult to select particular components later The layout should be tidy to enable components to be viewed and accessed easily Names and positions of components can be shifted to clarify the layout A background layer imported as a DXF file from a CAD program as described in Section 3 2 2 or as part of the importation of GIS files Section 3 2 4 provides a guide for locating pits and other components DRAINS User Manual 2 3 November 2014 Behind each of the components provided in DRAINS is a computer algorithm logic equations data that is employed within calculation frameworks There are often alternative ways to describe the operations of components such as pits or detention basins When performing analysis work with DRAINS you should assess the methods and equations used in the program detailed in Chapter 6 and examine results to confirm that the program operates as you expect You may encounter situations that are not fully described by the standard components such as a complex system of detention basins It will then be up to your judgement and modelling skills to use the available tools to describe the situation This may involve tweaking of the model An example
96. therefore recommended that this feature not be used and that models be created by other means However the transfer facility is still available and instructions are available in the DRAINS Help system under the topic Importing ILSAX files 3 2 6 Merging Files There is an option in the File menu to merge DRAINS files together Since this first involves an output process it is described in Section 3 5 8 DRAINS User Manual 3 9 November 2014 3 2 Transferring to and from CAD Programs Drafting programs such as AutoCAD Microstation IntelliCAD Bricscad and TurboCAD can be used for creating the network geometry In the drawing all pipes must be on a layer and all pits on a separate layer Pipes must be drawn as lines and pits as circles If the drawing uses other symbols for pits a separate layer should be created with a circle over each pit The file should be saved in DXF format At the time of import to DRAINS you will be asked to nominate the respective layers as described in Section 3 2 2 using the File Import gt Import DXF file command 3 2 8 Transferring Data to and from the 12d Program Data for setting up DRAINS models can be imported directly from the 12d digital terrain modelling program After design and analysis have been carried out in DRAINS using the ILSAX or ERM models the resulting system information can be returned to 12d for further analysis and plotting An important requirement is to ensure consistency i
97. times of flow can be varied by altering values in the spreadsheet output and re inserting these into DRAINS The DRAINS model can be calibrated or tuned so that the times of the calculated hydrograph peaks match those of the recorded ones A similar process can be carried out by varying the Hydrological Model parameters and percentages of land use to make the calculated flow peaks or volumes match the recorded ones This is more difficult because pervious areas may only contribute flows in larger storms and the gauging period may be too short or dry to record significant runoff producing storms From the available mapping and the survey data DXF or DWG drawings can be prepared and a suitable file prepared with the three layers containing pits as circles pipes and a background DXF files then can be imported into DRAINS to provide the initial file for the data entry and modelling processes As in Design it will be necessary to develop a set of guidelines on matters such as e the definition and modelling of flow paths e the factors used in pit inlet capacity relationships for the various kinds of pits encountered in the drainage system e pit blockage factors e existing pipe roughnesses and shapes and e the modelling of ponding of stormwater in streets and backyards In modelling existing systems a difficult issue will be the definition of the flow paths taken by flows from paved and grassed surfaces as shown in Figure 4 12 These
98. times that are multiples of the calculation time step that is a defined in the Options property sheet called from the Project menu or b automatically defined by DRAINS using various criteria including the requirement that unpressurised flows should take at least one time step to travel through any pipe in the system DRAINS results change when it is run with different time steps Most of the time users should accept the time step defined by the program This is determined so that it will take at least one time step for water to travel through each conduit The minimum time step is 0 005 minutes or 0 3 seconds and the maximum for pipe calculations is 1 minute Sensitivity tests can be carried out to determine a suitable time step If two time steps provide essentially the same results the longer one can be used Generally smaller time steps will give more accurate and stable results but this may not always be the case The hydrographs in all links begin at the same time the start of the storm rainfall pattern Any baseflows and user provided inflow hydrographs introduced at pits or nodes begin at this starting time User provided hydrographs can be specified at any time step but flowrates will be converted to the calculation time step by linear interpolation Where flow values are zero due to e losses absorbing the initial rainfalls e alag time or factor being specified for a grassed area hydrograph in the ILSAX model see Section
99. to a CAD Program Ej A 5 2 Viewing Pipe System Results worst Case minor storm If a model loaded into the Viewer contains run results you There Sinica ave aoe ee will see these straight away as coloured numbers as 4 0 minutes storm shown in Figure A 20 Since the overflow routes will 15 minutes storm probably be the most critical they are displayed in red ARAR 2 year 20 minutes storm AREA 2 year 25 minutes storm average 477 7 mmh 0 If this result comes from an ILSAX or ERM hydrological Als ee res ell ee al aie oe model it will probably be the maximum flowrate out of a AREA 2 eal 1 hour storm average 24 4 mmh Zone series of analyses of storm patterns You can view eE ER individual patterns by selecting them from the drop down menu at the top left of the Main Window shown to the right DRAINS User Manual A 22 November 2014 Overflow Route Flowrates m s Sub Catchment Flowrates m s Figure A 20 Displayed Flowrates and HGL Levels Note that flowrates in and out of a pit or node will not necessarily add to zero as they may represent conditions at different times or come from different storm events More accurate checks involving hydrograph volumes are provided in the spreadsheet output of results It is worthwhile to check the run report by selecting the Last Run Report option in the View menu This produces a report such as that shown in Figure A 21 This shows a warning that water is being lost f
100. to be referred to when setting up drainage systems The DRAINS drn file can be saved at this stage to be used later as a starting point for models that use this base information The saved file might be named Orange template drn or something similar DRAINS User Manual 1 9 November 2014 M Design Parameters Other Options r Simulation Options Minimum fall across pits mrm 30 Minimum clearance 100 Chainage increases to services mm You specify mins E 2 ona uRe ap t T Going downstream Fairfield Calculation time step f Pipes cannot be smaller Default Sag Pit Blocking Factor 0 to 1 0 0 5 than those upstream e Enable multi core Default On Grade Pit Blocking Factor 0 to 1 0 Do Pipes can be smaller processing 0 no blockage than those upstream OF r Pipe Friction Formula Colebrook w hite Cancel t ing Manning s Help Figure 1 12 The Options Property Sheet Note that not all options may appear Some may not be available with the hardware lock that is being used and others may be obsolete features in an older DRAINS model ACT Pits June 2008 db HS Pits June 2008 db1 Hel Queensland Pits June 008 061 all South Australan Pits Cec0S db1 South Australan Pits July 2006 db1 ae victorian Pits June 2008 db1 ammonty used in different Wid Pits November 2006 db1 ou can edit or
101. to define critical conditions requires some statistical skill and knowledge of local storms Where the system being analysed is a pipe system discharging into a larger pipe or trunk drain the level to be selected should be the higher of the receiving pipe s HGL or receiving open channel s water surface level at the junction Hydraulic calculations may be necessary to establish these levels but valid results cannot be obtained unless appropriate tailwater levels are used 5 Hydraulics of Open Channels The basic hydraulic method now obsolete projected water surface upstream along open channels using the standard step method Chow 1959 Henderson 1966 and other texts for subcritical flows For supercritical flows the critical depth line is traced and water depths are assumed not to fall below this providing a conservative estimate of depths DRAINS User Manual 5 36 November 2014 The unsteady flow procedures applied to open channels in the standard and premium model are the same as those for pipes outlined in Section 0 solving the mass and momentum flow equations Manning s equation is used to define channel friction Suggested roughness values for channels are given in Table 5 22 More comprehensive lists are given in texts and manuals on open channel flow and in Chapter 4 of Australian Rainfall and Runoff 1987 Table 5 22 Manning s Roughness Coefficients n Various energy losses can occur at changes or transitions in channel sec
102. to suit the 4Als specified for major and minor storms Time Area Routing uses Separate pervious and impervious areas C Total sub catchment area with calibration of Te Note Separate pervious and impervious areas are probably more realistic Total area with calibration of Tc will give a closer match ta peak tows from the standard rational method Figure A 12 Property Sheet for an Extended Rational Method Model The ERM peak flowrates will also differ from the rational method flowrates unless the following actions are taken a the Total sub catchment area option is selected in the box shown at the bottom left of Figure A 12 and b a synthetic rainfall pattern based on the I F D relationship for the site is applied instead of the ARR87 storm patterns which are not used by the rational method These issues are described in detail in the DRAINS User Manual and Help system The rational method is suited to basic pipe system design without storage effects but is a poor analysis model Assumptions about timing of peak flowrates must be made to estimate what happens in larger flood events and this becomes a more complicated task than running a hydrograph producing model The ERM provides a hydrograph model based on rational method principles This is unique to DRAINS and is not covered in manuals but the principles used are similar to methods commonly applied in the UK and US DRAINS User Manual A 13 November 2014 A 4 4
103. upper flow arrives as surface or open channel flows or if all arrives in a pipeline then it would be reasonable to apply a broad brush method such as modelling the entire upstream area as a single sub catchment But when upstream flows can arrive both on the surface and in pipes it is necessary to provide further detail upstream This may require all upstream pits and pipes to be included although this can be done in a rough manner at locations away from the site For example getting pit surface levels and pipe lengths exactly right will not be important but pit inlet capacities need to be described more accurately as these will define the proportion of upstream flows that enter the pipe system A 7 Conclusion This Guide originally issued with the DRAINS Viewer aims to provide useful advice for reviewers and designers that will make checking and assessment processes more efficient Further guidance is given in the publications on flood estimation in the reference list If you require more information or have comments on the contents of the Guide please contact the developers of DRAINS Bob Stack Geoffrey O Loughlin Watercom Pty Ltd Anstad Pty Limited 15 Little River Close 72 Laycock Road Wooli NSW 2462 Penshurst NSW 2222 phone fax 02 6649 8005 02 9570 6119 fax 02 9570 6111 0438 383 841 bobstack watercom com au geoff oloughlin tpg com au DRAINS User Manual A 30 November 2014 3 REFERENCES ACADS 1981 The Associati
104. use the Index Sheet facility described in the previous section DRAINS User Manual 3 14 November 2014 a Toowoomba Estate DRAINS File Edit Project View Draw Run Help D S Figure 3 21 Index Sheet View 3 Toowoomba Estate DRAINS File Edit Project View Draw Run Help plela S oleae eiee 0 aley lt r m P t Press F1 for help Figure 3 22 Toowoomba Pipe System selected using the Index Sheet Magnification Factor 1 5 Hint A factor greater than 1 will zoom in 4 factor less than 1 will zoor out Note Zooming affects the distance between nodes and the length of lines It does not affect the size of text or symbols reservoirs nodes etc OK Cancel Figure 3 23 Zoom Window DRAINS User Manual 3 15 November 2014 The Zoom Window option in the View menu changes the cursor to crosshairs that can be used to define the rectangular area that is to be enlarged When the mouse button is released the enlarged area fills the Main Window The Zoom Extents option zooms out but not to the full extent of the model It can provide the desired extent when applied a number of times d Property Balloons These can be switched on and off by clicking on Property Balloons in the View menu e Description Option Note that the Main Window area includes a title block in the lower right corner Text can be inserted into this block using the Description option
105. where A and n are coefficients h is the upstream measured water level above the weir and h is the downstream measured water level below the weir At headwalls and culverts the flow capacity is often limited by inlet control All flow models in DRAINS use the equations for culverts and headwalls presented in this manual to check for inlet control at these structures DRAINS also allows for the specified inlet capacity relationships at on grade pits as long as these are not submerged For sag pits a truncated inverted pyramid shape is assumed with the base length at the gutter invert level being half that at the overflow level Alternatively the user can specify a table of elevation versus surface area With the premium hydraulic model users must provide a weir control specification in the Overflow Route property sheet and water can rise above the maximum ponded level With the standard and basic hydraulic models water does not rise above the maximum ponded level rather any water above this level is assumed to immediately spill into the overflow route 5 6 5 Pipe Friction Equations For circular pipes you have a choice of the Colebrook White Equation or Manning s Formula The Colebrook White Equation employs the formula V 0 87 29 D S log es Equation 5 20 3 7 D D 2g D S where g is gravitational acceleration m s generally 9 80 m s at sea level D is diameter m S is energy line slope m m k is pipe wall
106. will be greatly influenced by the size and arrangement of allotments and the buildings on them and especially by the style of fencing along allotment boundaries lf there was no fencing or if flows could easily pass under fences the flows would follow the land contours and the definition of paths and overland flow lengths slopes and roughnesses would be relatively easy Once flows have to pass through fences or be directed along them the situation becomes quite complex with some storage effects probably coming into play Even in a detailed analysis with abundant scope for survey data collection it would be prohibitively expensive and complex to model each property s drainage system and to include possible storages Some judgements about overall or average effects must therefore be made Calibration with gauged data would be particularly useful for refining these judgements Another difficult issue will be the ponding of stormwater on streets and in backyards This occurs where development has occurred in the natural floodway areas and various barriers to flow have been erected including road crowns road embankments walls and fences It is fairly easy to see where stormwater will run into properties Usually those on the downstream side of a road at a low point will be affected as shown in Figure 4 13 DRAINS User Manual 4 15 November 2014 ae of Land Figure 4 12 Flow Paths to a Pit Street Yar
107. 0 18 0 316 i a a ie Clk Mine Ko hee Plena Mier Ko Maar Piette Summary Sheet FD eT E eap E pE 2D prami lt lt lt Figure A 26 Table for Gymea Design Example A 5 3 Reviewing Stormwater Detention and Retention Systems Detention basins in DRAINS usually involve three parts arranged as shown in Figure A 27 a basin component a pipe outlet and one or more overflow routes that represent high level outlets such as a weir overflow A sub catchment can be attached directly to a basin and channels and pipes can be directed into it The basin property sheet shown in Figure A 28 specifies the type of low level outlet pipe orifice sump etc and a relationship defining storages either an elevation surface area table or an elevation storage table In the second page tagged Infiltration Data information can be added that will allow stormwater infiltration to occur through the floor and walls of the basin Cat a e sti Cred Peak water levels upstream and just Ega s Overflow over downstream of the weir m s low level basin s outlet m AHD Pipe Outflow m s Figure A 27 Detention Basin Layout and Results DRAINS User Manual A 26 November 2014 Detention Basin Data Infiltration Data Name Basin 7 Low Level Outlet Type connecting to a pipe C Onfice Kentr Kbends 0 5 C Pit Sump f Circular culvert C Rectangular culvert None 5 2 3 4 5 6 T 2 E Faste Table No
108. 01 49 N9a 699 12 N9b 698 69 N 9c 698 61 Outlet 698 14 Pit C 1 705 6 Pit C 2 705 08 NO 702 13 Pit X 1 704 44 N1 703 84 HW 2 703 33 cu m s 707 3 0 186 0 041 706 69 0 134 0 033 705 5 0 187 0 106 0 09 0 045 2 429 2 746 1 022 1 1 1 747 1 74 1 734 0 314 0 218 0 117 0 166 0 78 0 952 SUB CATCHMENT DETAILS Name Max Paved Grassed FlowQ MaxQ MaxQ cu m s cu m s cu m s min min min Cat B 1 0 186 Cat B 2 0 041 35 CatB 3 0 134 0 073 0 115 0 035 0 006 0 06 0 076 M4 r Data Minor Sheet3 Flow Arriv Volume Freeboarc cu m s cu m m 4 3 0 53 0 068 None 0 79 0 None 4 1 0 82 0 None 0 79 0 None 4 3 0 95 0 068 None 1 17 0 None 0 93 0 None 0 179 None 0 047 Inlet Capacity 0 None 0 None Paved Grassed Supp Due to Storm Tc Tc Tc 1 AR amp R 2 year 30 minutes storm average 54 mm h Zone 3 0 AR amp R 2 year 20 minutes storm average 66 mm h Zone 3 0 AR amp R 2 year 30 minutes storm average 54 mm h Zone 3 Figure 3 44 Transferred Design Results As with the data results are organised by the type of component in the same order Calculated flowrates times velocities and other information are presented Where multiple rainfall patterns are specified the information presented is for the worst case result the greatest flowrate highest HGL level etc among the results for the various storms DRAINS User Manual 3 27 November 2014 The particular storm that causes thi
109. 014 Figure 5 10 Procedure for Determining AMCs for Design Purposes from Daily Rainfalls This classification involving soil type and AMC has been found to give good fits to recorded storm hydrographs from gauged catchments in Australia and the soil types have been accepted by ILSAX and DRAINS users Siriwardena Cheung and Perera 2003 compared the infiltration rates in Table 6 4 with those measured with infiltrometers at eight urban gauged catchments in Victoria They found that the fo and f values measured were generally higher than those for the same soil classification in Table 5 6 They obtained f values of 28 to 503 mm h compared to 13 mm h for a Type B soil and f values of 4 to 135 mm h compared to values of 31 to 200 mm h They also obtained a shape factor k of 0 85 h compared to 2 h in the table Siriwardena Cheung and Perera did not explore the implications of changing these parameters in modelling hydrographs from the test catchments It is not possible to assess the effects of this at present but Victorian users of DRAINS and similar programs should take the above results into consideration when setting parameters DRAINS s allows user provided parameter values to be specified in the hydrological model inputs In ILLUDAS SA and ILSAX the following form of Horton s equation was used to determine the infiltration rate from the accumulated depth of infiltration This allows for variable rainfall intensities that might be less
110. 04 3 24 and 4 44 m long x 0 12 or 0 14 m deep As above 1 0 2 3 3 6 and 4 0 m wide x 0 1m deep lintels 1 0 2 3 3 6 and 4 0 m wide x 0 1m deep lintels 1 0 m lintel 1 35 2 7 4015 and 5 4 m wide x 0 14 m deep 0 75 m 2 1 m and 3 45 m wide x 0 10 m deep 0 90 m x 0 61 m 0 90 m x 0 50 m 0 66 m x 0 614 m Maxflow and Mannflow Grates or Draincover 0 85 x 0 51m Macadam Manning Grates or Stormcover 0 675 x 0 31 m Hazen Grate One or two 0 5mx0 5m Hydraflow grate or infill cover Separate lip in line recessed relationships for D mountable and E barrier kerbs and two sets of kerb in line relationships for both D amp E kerbs The new relationships supersede the older ones that appear in the DMR Road Drainage design Manual 2002 and other manuals Relationships are given for 2 5 and 3 3 crossfalls and grades from 0 25 to 16 plus sags Separate lip in line relationships for a barrier or roll top kerbs and b transverse or longitudinal grates c 2 5 or 3 crossfalls and d grades from 0 25 to 16 and sags With a mountable kerb barrier kerbs with 300 mm and 450 mm channels b 2 5 or 3 crossfalls c 0 25 to 16 grades and sags With a mountable kerb rollover kerb barrier kerbs with 300 mm and 450 mm channels b 2 5 or 3 crossfalls c 0 25 to 16 grades and sags For mountable kerbs 2 5 and 3 crossfalls and grades from 1 to 16 and s
111. 10 Design mode 1 18 Design procedures 4 8 Design process 4 12 Detention basin 2 22 calculations 4 7 continuity equation 5 36 hydraulics 5 36 Detention basin circular pipe outlet 2 23 Detention basin elevation discharge relationship 2 26 Detention basin high level outlet 2 26 Detention basin low level outlet 2 22 Detention basin orifice outlet 2 22 Detention basin property sheet 2 22 2 23 Detention basin rectangular pipe outlet 2 23 Detention basin with no low level outlet 2 23 Dialog box 1 12 Directly connected impervious area 5 7 Dongle 1 4 DRAINS basic description 1 1 data file 1 22 demonstration version 1 5 display options 3 13 operations 4 2 output options 3 22 DRAINS development path 5 1 DRAINS Utility Spreadsheet 3 4 DRAINS Viewer 4 1 4 13 A 1 Draw menu 2 2 drn file 4 1 Drop pit 4 6 4 9 DXF exports 3 23 DXF long section 3 25 Edit menu 2 2 Enhanced design procedure 4 8 ERM 5 17 Error message 3 19 ESRI file formats 5 43 ESRI imports 3 4 Established drainage systems 4 14 November 2014 Evaporation 5 3 Existing drainage systems 4 14 Existing service 4 14 Expansion coefficient 2 29 5 36 Exporting ESRI files 3 30 Exporting MapInfo files 3 33 Extended Rational Method 5 17 Extending the calculation period 2 48 Fencing 4 15 File formats 5 42 File menu 2 1 Flood studies 4 18 Flooding problem locations 4 17 remedial works 4 17 Floodway grassed 2 31 Flow depth
112. 2 3 5 Or e a delay used to model a moving storm also see Section 2 3 5 an appropriate number of zero flows will be placed at the start of the hydrograph so that it begins at the rainfall pattern s starting time This common starting time simplifies the combination of hydrographs at junctions With the rational method model peak flows are calculated and stored with the data for each component Hydrographs produced by other models for sub catchments pipes channels overflow links and detention basins can be viewed as graphs or tables using the pop up menus for individual components and can be transferred to the Clipboard as shown in Figure 5 3 They also can be printed out in the Print Data and Results option in the File menu Calculated hydrographs and HGL levels are stored temporarily as part of each sub catchment object and can be retained in the saved drn file DRAINS User Manual 4 3 November 2014 The procedures for the storage routing models emulating the RORB RAFTS and WBNM models are simpler than those from ILSAX Results are presented in the same way as ILSAX hydrograph outputs in Figure 4 2 File Edit Total volume 288 2 cum Grase volume 230 5 cum Paved volume 49 7 cum nm Time Paved Grassed Total mins cums cums cums 0 0 000 0 000 0 000 0 055555 0 000 0 000 0 000 0 111111 0 000 0 000 0 000 0 166667 0 000 0 000 0 000 0222222 0 000 0 000 0 0 Orr re 0000 0 00 0 0 0 333333 0 000
113. 28 95 Pipe Type Concrete under roads v Downstream invert elev m 28 35 i Slope 1 27 P it B 2 a ree Piped ye a zag 27PitE t Nom Diameter mm I D mm Pit A 2 Pit A Bo Pipe 4 11 Pipe C 1 300 z 300 PPitAt2 3 No of identical parallel pipes 1 MPi C 2 F Include Non Retum Valve Pipe B 2 Pipe Roughness During Design runs this pipe A C Use default value 0 3 mm C is new diameter and level can change Pipe 4 12 Pe Pipe C 2 C is new but diameter and level are fixed Use 0 6 mm js existing diameter and level are fixed E _ a Rg j g Pit B 3 aaa aut TIPIES Notes Pipe B 3 f Pit D 1 i i ma T oe 29Pit B 4 ipe B 4 pP p 5 PEB V oppia py PEL 22PitC 4 poe per QUANTITIES Survey Data Excavation volume 21 6 cu m Rock volume N A Scale off Length Length of trench deeper than 1 2m 0 0 m i Help Pit A 15 ye Pipe A 15 al G Dutlet 4 WW p Press F1 for help Figure 3 11 Transferred Data b Importing MapInfo Files This process enables you to import data into DRAINS from one to six sets of MapInfo files plus an optional background from a DXF file The procedure is the reverse of the exporting process for MapInfo files described in Section 3 5 5 b and is similar to the ESRI transfer process described in the previous section of this chapter The six sets of files cover nodes pits and outlets pipes overflow routes sub catchments location of ground levels along the pipe routes a
114. 3500 3 2 15 Storage routing model theory 5 18 Storage routing models 1 3 Storage routing run results 1 30 Storage routing sub catchments 2 15 Stormwater ponding 4 15 Stream routing reach 2 32 Street drainage requirements A 5 Sub catchment property sheet 1 16 Sub catchments 2 11 Subdivision drainage systems 4 11 Supplementary area 1 15 2 11 5 3 5 7 Support for DRAINS 1 4 Surface elevation 2 4 November 2014 Surface overflows 4 6 Surface roughness factors 5 8 Surface types 5 6 Survey data property sheet 4 9 SWMM 1 4 Synthetic storms for ERM 2 44 Tab key operation 1 13 Tailwater level 4 6 5 35 Template file 3 37 Testing of DRAINS 4 19 5 14 Time lag 2 16 Time of entry 1 15 Time of flow 5 7 Time step sensitivity 4 3 Time steps 4 3 Title block 3 16 Toolbar 1 11 2 3 Trench widths 3 22 TRRL method 5 1 Trunk drainage requirements A 6 TUFLOW TSI file export 3 35 Uninstall DRAINS 1 5 Units 4 1 Unsteady flow calculations 4 5 Animation 1 29 Inputs 2 17 Unsteady flow examples 1 26 DRAINS User Manual Unsteady flow hydraulics 5 31 Upwelling 4 4 User provided inflow hydrograph 2 7 3 28 Velocities 3 28 Velocity depth product 1 23 Verification of DRAINS 4 19 5 14 Victorian pits 5 24 5 27 View menu 2 2 Viewer setup A 1 Viewing components and results A 21 Villemonte equation 5 32 Warning message 3 19 Watercom Pty Ltd 1 1 Watershed Bounded Network Model 2 16 5 19 WBNM
115. 39883 gen rne 120g aegre 0102383064 a pero ae4s 11420451528 GOB103908 1 66507693E 2 1 15419538 2 2722608E 3 O 7EMIGSE d 2810355985 RSOSSTITONT 5000500261 5920507E 7 1 1297484E 2 10570714 3 S00 0SG 4 4 74414457E 5 i EOGITHAOIIS 4 70R9017E 1 550307706 idaga 15090703 7 00570R0E a 53510A Fal erases G TASENSE 1 416977207 ORgeSMTE 2 1 2088211E 9 7 AGGE 6516871785 100 aaa n al Figure 2 64 Bureau of Meteorology Web Page To apply the process in DRAINS click the Add multiple ARR87 storms button in the Rainfall Data property sheet which will open the dialog box shown in Figure 2 65 DRAINS User Manual 2 42 November 2014 Add ARR87 Storms Sms gt Rainfall Zone Figure 3 2 of ARR87 Recurrence Intervals Zone 1 5 E Coast and Tasmania Antecedent Moisture Condition Zone 2 Murray Darling 1Year Zone 3 N E Coast Zone 4 Timor Sea and Gulf of Carpentaria Zone 5 Central Australia IW 5 Years Fone 6 5 A Gulf Zone 7 Indian Ocean Zone 8 5 W Coast 20 Years E 2 Years 10 Years Storm Durations W 5 minutes W 1 Hour 12Hours W 10 minutes W 1 5Hours 18Hours 15 minutes W 2 Hours 24Hours Calculate Average Intensities using BOM format table 20 minutes MW 3Hours 30 Hours using 9 coefficents from ARR87 25 minutes
116. 4 5Hours 36Hours 30 minutes 6Hours 48 Hours Note You can obtain BOM data from 45 minutes 9 Hours 72Hours www bom gov au Search for IFD table peras Figure 2 65 Add Multiple Storms Dialog Box The Zone of Australia ARIs and durations required can be entered as shown above Note that different antecedent moisture conditions AMCs can be provided for ILSAX models When the option of using BOM format table selected and the Next button is clicked this will open the following dialog box Paste BOM format table ram You can paste a table of IFD data in either of two BOM Bureau of Metoeorology formats The table of coefficients is recommended if you are using data from BOM because you are not limited to BOM storm durations e g 25 minute storms are possible The IFD table format is recommended if you are using non BOM e g Council data because you can setit up in a text editor use a BOM table as a template You can edit storm data e g add 25 minute storms remove unwanted ARIs For either table you should use the flash version on the BOM website to generate the table then press the Copy Table button on the BOM website You can edit the table in a text editor if required Then dick the Paste Table button below Figure 2 66 Paste BOM Format Table Dialog Box Now go to the flash BOM page and press the Create an IFD button The dialog box shown below will open
117. 42 Autodesk Land Desktop 3 35 Average recurrence interval 1 7 Background 1 12 2 3 Background colour 3 2 Background replacement 3 3 Baseflow 2 7 3 28 Basic hydraulic calculations 5 35 Basin elevation storage relationship 2 22 Blocking factor 5 25 Blocking theory new 2 6 Bolt down lid pit 4 6 Branching pipes 4 5 Bridge 2 35 4 7 5 42 abutment 2 35 pier 2 35 Brisbane City Council chart format 3 30 Bypass flow 2 4 Calculation of inflows 4 4 Calculation structure 4 5 Calibration 4 7 Catchment surface types 5 6 Channel breakout 2 28 Channel condition 2 32 Channel cross section 2 28 Check HGL procedure 3 28 Checking DRAINS models 4 13 Checking requirements A 3 Choke factor 5 25 Colebrook White equation 5 32 Coloured number display 1 20 Combination of hydrographs 5 13 Combining components 2 37 Comparing model results A 14 Computer aspects 1 4 DRAINS User Manual 1 1 Computing aspects 4 1 Continuing loss 5 3 Continuity check 3 28 Contraction coefficient 2 29 5 36 Copy data to spreadsheet 3 25 Copy results to spreadsheet 3 27 Culvert 2 35 4 7 5 42 Customise DXF drawing 3 24 Customise storms 2 16 Customise text dialog box 1 16 3 13 Customising storms property sheet 2 16 Data bases 2 2 2 38 A 18 Data entry 3 1 Default data base 1 9 Default Data Base 3 12 Depression storage 4 7 5 3 Description 1 22 Description property sheet 3 16 Design method 4 13 Design method 4
118. 48 Shepparton RAFTS Model Loss information and the routing parameter BX are entered in the hydrological model property sheet shown in Figure 1 49 Rainfall data is entered in the same way as for ILSAX models Property sheets for a sub catchment and a stream routing reach are shown in Figure 1 48 and Figure 1 50 Model Name Shepparton RAFTS Model Type Continuing Loss Type Cancel f Constant C Proportional Help Impervious Area Initial Loss mm 0 Impervious Area Continuing Lose mm h 0 5 Ferious Area Initial Loss rmm 10 Pervious Area Continuing Loss mmh 2 px Figure 1 49 RAFTS Hydrological Model Property Sheet The stream reach property sheet offers a choice of translation of the hydrograph movement of flows without changing the hydrograph shape or an approximate routing procedure based on kinematic wave hydraulic principles A name must be entered for nodes but surface levels are not required as the routing is not tied to particular elevations or datum levels Detention basins and completely defined open channels can be added if desired DRAINS User Manual 1 29 November 2014 Results from a major storm run involving four storms of different durations are shown in Figure 1 51 The black numbers at the sub catchments represent the routed sub catchment flows while the pairs of red numbers represent the peak flowrates at the top and bottom ends of a reach Hydrographs can be examined easily and data can b
119. 6 4 12 hour 23 9 27 7 40 8 51 0 62 2 78 8 93 0 24 hour 28 6 32 9 48 3 60 3 nE Ba 93 4 110 5 48 hour 33 4 38 3 55 6 69 2 83 8 105 9 125 0 72 hour 36 1 41 2 59 3 va 88 3 110 8 130 4 96 hour 37 9 43 3 61 6 T9 90 5 113 0 132 7 120 hour 39 4 44 8 63 1 76 7 91 6 114 0 ihe RF 8 144 hour 40 7 46 1 64 1 73 92 1 114 3 134 1 168 hour 41 8 47 2 64 9 fi 92 3 114 5 134 4 Figure 2 62 Depth Frequency Duration Table ii For each duration divide the depth by the duration in minutes and multiply by 60 to obtain the required intensity For example for a 20 AEP 30 minute duration the depth of 16 0 mm corresponds to an intensity of 16 0 30 60 32 mm h lii This needs to be applied with a 30 minute duration pattern from ARR87 which can be done applying the procedure in Section 1 2 1 a as shown below DRAINS User Manual 2 41 November 2014 Select a Pattern from Australian Raintall and Runoff Rainfall one Figure 3 2 of SARS Storm Duration one 1 5 E Coast and Tasmania 30 minutes one 2 Murray Darling one 3 M E Coast one 4 Timor Sea and Gulf of Carpentaria Central Australia P P m m m e Indian Ocean Si Coast o Annual Recurrence Interval pears 5 IFO Data Cancel Average Intensity mmh ce lt Cale Help Figure 2 63 Date Entry for 2013 Design Rainfall Pattern Pressing OK will produce the required pattern A suitable title for this 2013 interim estimate can be ent
120. 8 4 10 5 9 RAFTS 5 19 BX parameter 1 29 DRAINS User Manual 1 3 routing equation 5 19 RAFTS model property sheet 1 30 RAFTS Model sub catchment property sheet 2 16 RAFTS reach property sheet 1 30 RAFTS sub catchment property sheet 1 30 Rainfall data 1 7 1 24 Rainfall data property sheet 1 8 Rainfall multiplier 2 16 Rainfall pattern 1 7 Rainfall pattern data base 2 40 Rational Method 1 2 Rational method frequency factors 5 17 Rational method output converter 3 30 Rational method runs 1 23 Rational method sub catchment property sheet 2 15 Rational Method sub catchments 2 14 Rational Method theory 5 16 Reviewing analyses A 29 Reviewing results 1 20 Revise pit loss coefficients 3 19 RORB 1 3 5 19 RORB Model sub catchment property sheet 2 15 Roughness coefficients 5 36 Routing models 5 3 Run log 3 18 Run menu 2 3 Run options 3 16 Running an ILSAX design model 1 5 Running DRAINS 1 18 Running storage routing models 1 26 1 28 Sag pit 5 22 orifice flow 5 22 weir flow 5 21 Screen capture techniques 3 22 Screen presentation options 3 13 Sealed pit 2 5 4 6 Shapefiles 3 31 Simple node 2 8 Simulation models 5 2 Soil type 4 7 5 10 South Australian pits 5 26 Spreadsheet documentation 4 17 Spreadsheet file formats 5 45 5 46 Spreadsheet imports 3 4 Spreadsheet transfer 1 20 Spreadsheet transfers 3 25 St Venany equations 5 31 Standard design method 4 8 Standards Australia AS NZS
121. 845 0 061 0 048 0 02 Pit B 1 0 0 0 0 0 Sutherlan 0 007 0 001 DRA II 20 Outlet Pit A 3 0 0 0 001 0 0 21 22 Partial Area 23 24 Figure 3 47 Transferred Check HGL Results Queensland users will be able to convert the DRAINS Check HGL outputs to forms set out in QUDM and manuals from Brisbane City Council and Pine Rivers Shire Council using a DRAINS Rational Method Output Converter spreadsheet available from www watercom com au An output from this is shown in Figure 3 48 DRAINS Queensland Rational Method Output Converter March 2008 xls Compatibility Mode Microsoft Exc M LE te Nore F PINE RIVERS SHIRE COUNCIL CALCULATION SHEET LOCATION TIME SUBCATCHMENT RUNOFF INLET DESIGN 1 2 3 4 E ee ee ee ee en a ey Design Structure Drain Sub Surface Slope of Sub Rainfall Runoff Sub quivalen Sum of Jischarg Origin of low pasi Kerb amp Road K Flow Flow Gutter Depths Inlet ARI Number Section atchmen_onditioratchmer atchmerIintensity ocefficieratchmernperviou quivalen Q C 1 4 Over PreviousChannel Grade K width Width Depth Flow Velocity Numb years Contrib Percent 3 4 te Immih C Area Area nperviou m s Flows Gullies Flow at Inlet Im m atInvert Velocity m s uting npervious minutes Iha Iha mts m Is x Im Imis Pit4 1 Pipe 1 Catt 35 Add 12 110 0 614 0 772 0 474 i 0 145 Node 4 1 0 087 3 dsection 2 31 0 108 0 395 0 1 Pit4 1 Pipe 1 Cat 35 Add 12 183 0 748 0 772 0 577 0 294 Mode A 1 0
122. AFTS type of storage routing model with the inputs shown in Figure 2 29 If this feature is enabled your hardware lock you can model urban overland flow paths using the kinematic wave routing procedure While this has some advantages over the basic calculations for overflow routes from pits the best procedure is to employ the premium hydraulic model if this is available DRAINS User Manual 2 19 November 2014 Overflow Route OF K Basic Data Cross Section Data N OF KA r Fow Routing in Basic and Standard Models ame Simple Translation no attenuation Kinematic Wave Reach Length im 338 Scale off Length Figure 2 29 First Page of the Overflow Route Property Sheet with Kinematic Wave Routing Top Portion e Definition of the Flow Cross Section On the second page you should specify an overflow path cross section from the Data Base set up in the Project menu described in Section 2 4 7 The section may be a roadway as shown in Figure 2 30 ora trapezoidal rectangular or other channel shape Overflow Route OF Es Basic Data Cross Section Data Shape 14 m wide road half section Safe Depth for Major Storms m 0 3 Sate Depth tor Minor Storms im 0 15 Sate Depth x Velocity sq m sec 0 4 X of downstream m by this channel Channel slope 7 27 Cale Slope Figure 2 30 Cross Section Data Entry in Overflow Path Property Sheet Here it is necessary to select a a shape
123. AINS but is limited to inspecting data and results saved in a drn file It can also export spreadsheet and CAD outputs 4 2 3 Data Storage and Files To run DRAINS requires run specifications rainfall data and a pipe or channel system This data is stored temporarily in the computer s memory and more permanently in a binary data file with a drn suffix such as the sample files that have been described in this manual After a data file has been saved you can re open it in DRAINS and modify the data Since it is saved in binary format it cannot be viewed or changed using a text editor The binary file formats change as DRAINS is updated but will always be back compatible That is the current version of DRAINS will open and operate with files created in previous versions You will probably not be able to open files created with a later version of DRAINS than the one you are using it is not forward compatible Each DRAINS drn file is effectively a data base describing a drainage system and its components together with reference data bases for pipes pits and overflow routes and possible the results of a run Most of the data on the drainage system can be readily accessed in ASCII or text form using the spreadsheet output option described in Section 3 5 4 Data on rainfall patterns hydrological models and run specifications are not transferred to spreadsheets As well as the sets of pipe pit and overflow route types and associated informat
124. At only sub area A1 contributes to the flow at the outlet Any runoff from other sub areas is DRAINS User Manual 5 5 November 2014 still in transit to the outlet Thus the flowrate at the end of the first time step can be approximated by Q c A l where c represents the conversion factor from mm h to m s units and 11 is the average rainfall intensity during the first time step At the end of the second time step there are two contributions to the outlet flow Q2 due to the second block of rainfall falling on the sub area nearest to the outlet c A4 l2 and to runoff from the first rainfall block on the second sub area c A2 h At the end of the third time step there are three contributions Q c A4 l3 A2 l2 A3 l1 and so the process continues as shown in Figure 5 5 The hydrograph builds up to a peak and then recedes once rainfall stops and the catchment drains In practice losses can be subtracted from the rainfalls and flows before or after these time area calculations are made The latter choice is recommended for grassed or paved areas as this allows infiltration to occur from flows moving across a sub catchment after rainfall has stopped In this case the hydrograph of Q values represents a supply rate from which losses must be subtracted later In DRAINS as in ILSAX it is assumed that all time area diagrams are straight lines Itis conceivable that they could be concave or convex depending on catchment shap
125. Australia ae Kerb Inlet Comments ae Dimensions ae Bay 0 9 m long none On grade relationships with and Transport SA without deflectors Double Bay 1 9 m long none On grade and sag relationships with and without deflectors City of Adelaide on Pit 0 9 m long 0 5 m long x On grade and sag 0 54 m wide Campbelltown with and without deflectors City of Charles deflectors and transitions eon Double Pit 1 9 m long City of Marion Double Pit 1 9 m long none On grade and sag with and without deflectors Single Bay 0 9 m long 0 9m x 0 45m On grade without deflectors City of Mitcham Double Bay 1 9m long On grade and sag with and without deflectors City of Double Pit 1 9 m long none As above Onkaparinga City of Port Double Pit 1 9 m long On grade with and without Adelaide deflectors Enfield Triple Pit 1 9 m long none Different bay arrangement On grade with and without deflectors City of Salisbury Double Pit 1 9 m long none On grade and sag with and without deflectors City of Tea Tree Double Pit 1 9 m long none On grade and sag without Gully deflectors City of West Double Pit 1 9 m long none On grade and sag with and without Torrens deflectors Table 5 18 Western Australian Pits Developed from Department of Main Roads drawings and Generic Spreadsheet using HEC 22 procedures None are based on measured data Kerb Inlet Pit Type Comments mensions n Comments Main Roads Side cz 0 88 m long On grade relationships
126. Australia ILLUDAS SA and various development versions of ILSAX were applied to data from gauged urban catchments in Sydney and Melbourne by Cartwright 1983 Mein and O Loughlin 1985 Vale Attwater and O Loughlin 1986 and others The first practical application was in a large scale drainage study of Keswick and Brownhill Creeks in suburban Adelaide in 1982 83 ILSAX was developed by Geoffrey O Loughlin between 1982 and 1986 with the aim of producing a better stormwater drainage design program than the rational method The later part of this development occurred alongside the preparation of the chapter on urban stormwater drainage in Australian Rainfall and Runoff 1987 ILLUDAS SA was adapted to model overflows from pits so that it could model major storm flows in the major minor design system recommended in Australian Rainfall and Runoff However the program did not calculate HGLs ILSAX started to be used widely in 1986 when it was released in a public domain version for IBM PCs Its flexibility low cost and robustness made it acceptable despite the limitations of its hydraulic calculation method The early testing showed that the hydrological model was at least as accurate as alternative urban hydrology models In the 1990s it was commonly used for analysis of on site stormwater detention systems It has now been superseded by DRAINS and is no longer supported PIPES and PIPES are hydraulic network analysis programs developed in the 1990
127. Basic Data Cross Section Data Shape Creek Section 1 cope Gube ba bu Sate Depth tor Major Storms m 0 3 Sate Depth tor Minor Storms im 0 3 You specify Safe Depth x Velocity sq m sec 0 6 X of downstream catchment flow camed 0 by this channel Channel slope 72 14 Cale Slope Figure 2 51 Second Page of the RAFTS Stream Routing Reach Property Sheet DRAINS User Manual 2 33 November 2014 When run the kinematic wave option will produce two hydrographs at the top and bottom ends of the reach with a small reduction in peak flows As noted in Section 2 3 6 this specification can also be applied to conventional overflow routes in piped urban drainage systems but the premium hydraulic model calculations are preferable The WBNM stream routing reach property sheet shown in Figure 2 52 requires only a name and a stream lag factor When this factor is not zero routing occurs along the reach using parameters based on the area of the sub catchment at the node at the end of the reach Overflow Roure Reach I Basic Data Name Reach Stream Lag Factor Ex Figure 2 52 WBNM Stream Routing Reach Property Sheet Top Portion 2 3 14 Headwalls The headwall ol allows open channels to be connected directly into a pipe system and overflows to be directed to other locations It is not to be used as the outlet of a pipe system which is modelled as a node The Headwall property sheet is shown in Figure 2
128. Basically this is ku 0 5 2 Se 4 amp Equation 5 24 Q Qo where Q is the inflow from upstream pipes that are misaligned Q is the aligned flow Q is the grate inflow and Q is the outflow equal to Qm Qa Qg 0 DRAINS assumes that pipes at angles of 45 or more to the outlet pipe are misaligned A value of 0 5 is subtracted if the outlet pipe diameter is larger than that of any of the inlet pipes For a drop pit the incoming flow from a pipe may be classed as grate flow if the inlet pipe s invert is located above the pit water level Mill s assessment of misalignment of incoming pipes cannot be judged automatically by DRAINS DRAINS User Manual 5 35 November 2014 This procedure is implemented by performing a Design run and then choosing the option Revise Pit Loss Coefficients in the Run menu This changes the original coefficients using the flows determined in the previous design run thus overcoming the difficulty of having to estimate k factors roughly in advance when exact flows are not known The procedure can also be implemented after an Analysis run This may lead to somewhat different coefficients because the relative values of Qm Qo and Q may be different The process can be repeated to refine the result It must be noted that this procedure is approximate and may give poor estimates for some situations The estimated coefficients need to be checked and corrected where necessary c The QUDM Method
129. Cancel Help dd Ok Help Faintall Intensity for 60 55 minute 10 Year storm Cancel Figure 2 59 Rational Method Selection Property Sheets Many models of different types can be stored in the Hydrological Model data base The hydrological model that is selected in the Hydrological Specifications dialog box acts as a default model that applies to DRAINS User Manual 2 39 November 2014 all sub catchments However in many cases a local model can be selected in the property sheet for a particular sub catchment as shown in Figure 2 60 Default Model for Design and Analys Sub catchment name Cat 1 Orange Soils Use Rational Method Hydrological Model G wedded dais Urange Sails Orange Clays C Default model You specify Orange Sand In addition to the Ilsax model you m ome of the following models in this p IF You wish pou may select one Orange Clays Paved C RORE Orange Clays T C RAFTS CO WENM Sub catchment area ha 0 125 more detailed data Supplementary Ys EE Grassed 3 Lag time minutes 0 Figure 2 60 Selection of a Default and a Local Hydrological Model 2 4 4 Rainfall Data Bases a New ARR2013 Procedures At the time of updating this manual the Commonwealth Bureau of Meteorology and Engineers Australia are in the process of introducing new sets of design rainfall for all of Australia as set out in http www bom gov au water designRainfalls ifd ind
130. Cat B 1 Area 0 593 ha Paved Area 50 Te 8 0 min Grassed Area 45 Tc 13 0 m Supp 4rea 5 Te 1 0 min Cat C 1 Area 0 411 ha Cat A 3 Paved Area 55 Tc 6 0 mir M ce l Area 0 061 ha Grassed Area 40 Tc 10 0 Paved 4rea 80 Tc 2 5 mir Supp Area 5 Te 1 0 min i Grassed Area 204 Te 3 0 r Supp Area 0 Te 0 0 min Cat A 4 Area 0 382 ha Paved Area 10 Te 6 0 min Grasted Area 90 Tc 18 0 mit Supp Area O Te 0 0 min Figure A 13 Gymea Model used for Comparisons Peak flowrates for 5 and 100 year ARI are shown for each sub catchment Those from the ILSAX models and the ERM with ARR87 storms are the highest values out of twelve storm patterns with durations from 5 minutes to 4 5 hours DRAINS User Manual A 14 November 2014 Table A 9 Characteristics of Comparative Gymea Model Sub Catchments Hydrological Model ILSAX Rational Method and ERM Sub Area Paved Catchment M8 Supplementary Supplementary Pervious a Pervious Pe Perv amp Grassed j nc tc te minutes Co Co 30 5 65 canz om moa sos foa ase os fos 80 0 20 eaaa ose 10 0 0 eow wo 618 os fos cant os s548 8118 5545 81s 09 ost w os os Table A 10 Comparison of Flowrates and Volumes Generated by Gymea New South Wales Pipe System Models Hydrological Model Sub ILSAX with Soil Type of 3 and AMC of ERM with Catchment apetega Rational Separat
131. Clear opening area g m Maximum ponded depth rn Figure 5 27 Dialog Box for Sag Pit 5 6 Pipe System Hydraulics 5 6 1 General The hydraulic models used in design and analysis of urban stormwater drainage systems can be considered to operate at three levels e open channel hydraulics assuming steady flow and normal depth conditions described as pipe full but not under pressure in Australia e part or full pipe flow calculations determining hydraulic grade lines HGLs and water surface profiles e full hydrodynamic modelling usually involving a finite difference solution of the partial differential equations for conservation of mass and momentum the St Venant Equations ILSAX calculations operate at the first level so their hydraulics is quite limited The same applies to the calculation of flow characteristics in overflow routes in the standard and obsolete basic hydraulic models Table 5 20 Qualitative Indication of the Accuracy of the HEC22 Procedures Inlet Capacities from HEC22 Procedure relative to Laboratory Results Inlet Type Approach Approximate Length of On Grade Inlet Flow Range 1 m or Shorter Between 1 amp 3 m 3 m and Longer Grate Only gt 0 5 m s Underestimates by about 25 Kerb Inlet Only lt 0 15 m s 25 over for un 25 20 depressed inlet underestimate underestimate 50 under for depressed Kerb Inlet Only 0 15 to 0 5 m s 25 33 10 underestimate underestimate underestimate Kerb Inlet O
132. Comparison of Hydrological Methods for Piped Drainage Systems This section provides comparative information on the three models provided by for use with piped drainage systems An example based on the Gymea model is shown in Figure A 13 and the sub catchment characteristics relevant to the ILSAX and rational method models are shown in Table A 9 The focus is on the runoff produced by the sub catchments and flows in pipes are not considered in this assessment An additional sub catchment has been added at the outlet to model a sub catchment that is mainly pervious Table A 10 sets out the results of a series of runs made with the modified Gymea model Four ILSAX models apply a typical Soil Type of 3 and AMC values of 1 2 3 and 4 The rational method uses a 10 year ARI pervious area runoff coefficient of C 0 51 based on a 10 year ARI 1 hour intensity of 56 mm h to develop 5 and 100 year ARI coefficients of C 0 48 and Cio 0 61 The extended rational method ERM uses the same coefficients but is applied in three ways with ARR87 and synthetic storms being used and impervious and pervious runoff being calculated separately or on a total basis Times of concentration are consistent for all models Cat A 1 Area 0 72 ha Paved Area 30 Te 5 0 min Grassed Area 65 Te 12 0 min Supp Area 5 Te 1 0 min Cat A 2 Area 0 080 ha Paved Area 80 Te 2 5 min Grassed Area 20 Te 3 0 mi Supp 4rea 0 Te 0 0 min
133. D Data taken from ARRS Volume 2 DRAINS can use thie data to calculate the LPIll rainfall intensities required on OK the previous dialog The data below should be read from maps in Australian Rainfall and Runoff Volume 2 Cancel IF you are not reading data from AAA Volume 2 you should click the Cancel button row Help Year 450 Year 1 Hour Rainfall Intensity ramhour 25 ol G 0 27 12 Hour Rainfall Intensity mm hour 4 45 Tro Fe 432 T2 Hour Rainfall Intensity mmi hour 1 22 2 08 F50 15 6 Figure 1 41 Factors from Australian Rainfall and Runoff 1987 Volume 2 The remaining property sheet that is different is for sub catchments shown in Figure 1 42 The rational method does not distinguish between directly connected and non directly connected impervious areas The paved and supplementary area percentages are added to produce a percentage impervious and the ILSAX model grassed area becomes the pervious area The data that needs to be entered for sub catchments is presented in Table 1 5 and run results are shown in Figure 1 43 The flowrates differ from those provided by the ILSAX model in Figure 1 31 The results provided by the alternative models are discussed in Section A 4 4 of the Appendix Sub Catchment Data Rational Method So Sub catchment name Cat 1 Sub catchment area ha 0 125 Use Hydrological Model f abbreviated data f Use default C more detailed data f fou specify Impervious Per
134. Data BaSe a a E Slaw ota E 2 53 OPTIONS WITHIN DRAINS Set AOC CHOI eein ede ntcen tantra tnentauntteniaeeseaudareteensaentceceaecseeceace 3 1 32 1 10 0 6 f rna eR ae oe 3 1 eZ TCU ell eats ticeistaat Sec hoe cesese vec a a a ane eee actene A 3 1 322 UMPON DAF FIOS 2c cin few sacealcied seca waster deta tie adaasdtinn tune E tet a E tee EN 3 2 3 2 3 Spreadsheet NINPOMS aicccccicccoenluiccetedance rah eicd el deoeuahed cosine diaeeen deans redesainlcd ek biee een ddeoecn tien 3 4 22A bee 2 9g 9 9 6 eee ne cnr mE Sn RO rors a ee oe ane ree ee eee 3 4 O20 ILO AX Piles IIMPOMeS eaaa cunts ct toe E etat aa eel E a A R AA 3 9 I2 O Merging File Sase a a a ia iain dessunnd yng 3 9 3 2 7 Transferring to and from CAD Programs ccccseeceeeseeeeeeeeeeeeeeaeeeeeesaeeeessaeeeeseaeeeeesaeeeeeeas 3 10 3 2 8 Transferring Data to and from the 12d Program cccccccsseceecseeeeeeeeeeeeeeaeeeeesaeeeeesaeeeeeeas 3 10 3 2 9 CADApps Advanced Road Design LINK cceccccceececeeececeeeeceeeeeeeeceeseucesseeeesseeeseeeeeseaees 3 11 3 2 10 Transterming trom MXROADS anesan a i aa nies a deeb ee baer a a a acess 3 12 3 2 11 Transferring from CatchmentSIM ccccccssececcesseeecsesseecseaeeeceeseeecsaseesseageeessageeesseseeseas 3 12 3 2 12 Setting Up New Pipe Pit and Overflow Route Data Bases cccccceccecseececeeeeeeeeeeseeees 3 12 29 DISDIEYODUOMS ci contesticonicstscenteatzesniasiuac
135. Data Base Default Data Base Run Help 7 Node Pipe Overflow Route RORE WBNM Stream Prismatic Channel Irregular Channel Multi Channel Pump Bridge Culvert Headwall Detention Basin Drainage Pit Sub Catchment November 2014 2 2 7 The Run Menu Help Analyse major storms standard hydraulic model This includes various options for making runs and for Analyse minor storms standard hydraulic model varying these Depending on circumstances this menu Analyse major storms premium hydraulic model can take different forms the first shown to the right being Analyse minor storms premium hydraulic model for new models Design For models created prior to December 2010 it is also ee El Des Coen i possible to run with the obsolete basic hydraulic model which has been replaced by the standard model Help Quantities Analyse major storms standard hydraulic model The run menus for rational method models and for storage Analyse minor storms standard hydraulic model routing models will be less complicated than those Analyse major storms premium hydraulic model shown Analyse minor storms premium hydraulic model Analyse major storms basic hydraulic model Analyse minor storms basic hydraulic model Design Revise Pit Loss Coefficients Quantities 2 2 8 The Help Menu Contents This contains an access point to the Help system through the Contents erated aes option and also identifies the version o
136. Data Drains the ACT or Queensland pit types will be installed DRAINS uses separate folders in C Program Files and C ProgramData because of Microsoft Vista rules for handling files for applications DRAINS still accepts old files that use the ILSAX equations described in Section 5 5 1 for pit inlet capacities However if you attempt to run the Design method the following message will appear It would then be possible to import a new Pit Data Base and to alter each pit s type to conform to this i xX This file uses an old pit data base format You can do Standard Design pipes only but not Advanced Design pipes and pits with this format in place If you want to do Advanced Design for this job you will need to import a new pit data base and redefine prt and overflow route types Do you wish to import a new data base now DRAINS User Manual 2 52 November 2014 2 4 7 Overflow Route Data Base The property sheet opened from the Overflow Route Data Base in the Project menu is shown in Figure 2 81 Using X Y coordinates a cross section can be defined for a roadway footpath or other route that may operate as a path for overflows Overflow Route Cross Section Data Base Name 8 m wide road half section x i m m 0 15 aor 24 0982 2405 0 802 285 0856 64 0363 6401 15 co M OF Fe w Fa Sect has main channel plus Left Over Bank LOB Main Manning O12 Flow Correction
137. Determine Hydraulic Capacities of Kerb Inlets and Gully Pit Gratings Sydney 1979 Normann J M Houghtalen R J and Johnston W J 2005 Hydraulic Design of Highway Culverts Hydraulic Design Series HDS 5 2nd Edition Federal Highway Administration Washington DC O Loughlin G 1993 The ILSAX Program for Urban Stormwater Drainage Design and Analysis User s Manual for Microcomputer Version V2 13 Civil Engineering Monograph 93 1 University of Technology Sydney fifth printing first version 1986 O Loughlin G G Darlington D and House D 1992 Mathematical Description of Pit Entry Capacities E Aust International Symposium on Urban Stormwater Management Sydney O Loughlin G G Haig R C Attwater K B and Clare G R 1991 Calibration of Stormwater Rainfall Runoff Models Hydrology and Water Resources Symposium E Aust Perth O Loughlin G and Stack B 2002 Algorithms for Pit Pressure Changes and Head Losses in Stormwater Drainage Systems 9th International Conference on Storm Drainage ASCE Portland Oregon Pereira J 1998 Gauged Urban Catchment Study at Jamison Park Penrith Undergraduate Project Faculty of Engineering University of Technology Sydney Pezzaniti D O Loughlin G G and Argue J R 2005 General Characteristics of Pit Inlet Capacity Relationships poster paper 10th International Conference on Urban Drainage Copenhagen Poertner H G editor 1981 Urban Stormwater Management Americ
138. Engineering Circular No 12 Authors Johnson F L and Chang F F M Office of Engineering Office of Technology Applications Washington DC U S Federal Highway Administration 2009 Urban Drainage Design Manual Hydraulic Engineering Circular No 22 3 Edition S A Brown J D Schall J L Morris C L Doherty S M Stein and J C Warner National Highway Institute Arlington VA and FHWA Office of Bridges Washington DC U S Natural Resources Conservation Service 2007 National Engineering Handbook Chapter 7 Hydrologic Soil Groups http directives sc egov usda gov OpenNonWebContent aspx content 17757 wba U S Soil Conservation Service Department of Agriculture 1975 Urban hydrology for small watersheds Technical Release 55 Washington DC Upper Parramatta River Catchment Trust 2005 On Site Detention Handbook Version 4 Parramatta available for download on www uprct nsw gov au Vale D R Attwater K B and O Loughlin G G 1986 Application of SWMM to Two Urban Catchments in Sydney E Aust Hydrology and Water Resources Symposium Brisbane VicRoads 1994 Road Design Guidelines Part 7 Drainage Melbourne Watkins L H 1962 The Design of Urban Sewer Systems Research into the Relation between Rate of Rainfall and Rate of Flow in Sewers Technical Paper No 5 U K Department of Scientific and Industrial Research Road Research Laboratory Watkins L H and Fiddes D 1984 Highway and Urban Hydrology in the Trop
139. Factor a coordinate of ROB Manning 014 Main POE dividing 2 05 Safe Depth for Major Storme m 0 3 Safe Depth Velocity sq m sec 0 4 Safe Depth for Minor Storme m 0 15 Add Cross Section Delete Cross Section Paste Y data eo Figure 2 81 Overflow Route Cross Section Data Base Property Sheet At present the section may be divided into two zones with different Manning s n roughnesses by specifying these and the X value of the dividing line As X Y values are entered the picture shows the section being produced In the boxes at the bottom you can specify safe depths for minor and major storms and a safe depth velocity product These are applied at selected cross sections in the Design method DRAINS works backwards to ensure that overflows from pits are kept to levels that will meet these safety criteria It does this by providing pits and pipes with the appropriate capacities to do this following procedures within the Queensland Urban Drainage Manual Neville Jones amp Associates et al 1992 DRAINS User Manual 2 53 November 2014 DRAINS User Manual 2 54 November 2014 X4 3 OPTIONS WITHIN DRAINS 3 1 Introduction Most of the functions or processes within DRAINS are presented here referring to the example files that accompany this manual They are arranged into e Input Options e Display Options Run Options e Output Options and e Help Options 3 2 Input Options 3 2 1
140. File Edit Project View Draw Run Help Dem S oo ee ftnlw oo e us Outlet 2 Figure 2 40 Detention Basin with Special Orifice and Weir Outlets The property sheets for the Orifice and weir are shown in Figure 2 41 7 Overflow Weir Pr ries Orifice ere Mame Weir 2 pie aa Cdisch Li Rectangular side spill Crest Elev m 36 7 C V notch Crest Length m 18 Name Orifice 1 Diameter mm 120 Cd 0 61 No flow elev m 35 7 C Trapezoidal The weir equation is Q Cdisch x L xH k where k depends on the weir type you select Figure 2 41 Special Orifice and Weir Property Sheets DRAINS User Manual 2 27 November 2014 2 3 9 Pumps As described in the previous section pumps can be modelled with an overflow route coming out of a detention basin Howe However this can cause problems when applying the premium hydraulic model and a specific pumping link has been provided When the tool ped is selected a pump link P can be drawn This must come out of a detention basin and can be directed to a pit a simple node or another detention basin The associated property sheet shown in Figure 2 42 requires a level at which the pump switches on and off relative to the water level in the basin out of which it comes and a table of water elevation vs flowrate Pump from Basin 71 to Reuse Pump starts when water level at 491 6 Basin Z1 rises to RL m Water Flow i RL m cu m s OK
141. General The example file in Chapter 1 was established using the screen tools provided on the Toolbar and their associated property sheets Other options are available that allow a substantial part of the information required to be inputted by other means These are mainly implemented through the File menu shown in Figure 3 1 and the two additional menus that are opened using the Import gt and Export options Note that not all options may appear when the hydrological model in DRAINS is set to be a rational method model Edit Project View Draw Run Help t Import DXF file Open 4 ESRI Shapefiles Cire Mapinfo MIF Files LD File save Ctrl 5 Advanced Road Design File aiia ILSAX Files Import Merge File Export DRAINS Database DB1 File Print Diagram Ctrl P E DXF Long Section 1 Existing Ipswich drn DXF Plan 2 ilsaxlO drn ETA ESRI Shapefiles i Mapinfo Files 4 ilsaxlO drn i 12D Connection Data File Exit Advanced Road Design File ae Tuflow TS1 Files Merge File Drains Template File Figure 3 1 The File Menu and Sub Menus showing Import and Export Options In design work it is likely that considerable data will be available from CAD files created by surveyors and used by designers to set out street layouts cadastral land boundary data and positions of services Some of this data can be taken directly into DRAINS by importing CAD files in DXF
142. Hydrograph Copy Shape Pit View HGL Graphs View HGL Tables Name Pt A2 Surface Elev m 32 3 Delete e pe Famiy Sahetand 3 cvsdel aldopes Pit Size kerb inlet with 0 85 m lintel 3 crossfall all slopes X a Pressure effi re loss coefficient 05 C t Ku for full pipe flow omponents and Names T Pit has bolt down impermeable lid f es This pit is Blocking Factor 0 to 1 0 0 unblocked New can be designed Use default value of 0 7 F Existing cannot be designed You specify N t o M Notes T a Pipe A 3 Cancel Helo 4 Press F1 for help Figure A 2 Gymea Pipe Drainage Example before a DRAINS Run Running DRAINS requires suitable data bases for hydrology rainfall data pipes pits and overflow routes that can be viewed using options in the Project menu After a run the component names change to colour coded values of peak flowrates and the levels of hydraulic grade lines HGLs at pits and nodes as shown in Figure A 3 Models can be saved with data and results intact as a DRAINS drn file f 7 a Gymea ILSAX Example with Results Standard DRAINS Viewe AY Pit C 1 HGL AR amp R 5 year 25 minutes storm average 78 m E Z _ 3 Pipe C 1 Hydrograph AR amp R 5 year 25 minutes storm average 78 E 2 File Edit Project View Draw Run Help Edit Properties e Diek S 2 a 5 ae AR amp A 5 y
143. Hydrographs As well as receiving surface flows a pit can receive a constant baseflow or a user provided inflow hydrograph specified using the buttons at the top of the Drainage Pit property sheet These can be introduced at the surface or inside the pit Flows introduced inside the pit are not subject to the pit inlet capacity relationship DRAINS User Manual 2 7 November 2014 When the Baseflow button is clicked the property sheet shown in Figure 2 8 appears Only a single flowrate is entered Basetlow into Pit eee Baseflow 0 004 cums Flow enters ence Atthe surface Help Figure 2 8 Baseflow Property Sheet When the Inflow Hydrograph button is clicked the window shown in Figure 2 9 is opened To specify a hydrograph a set of hydrograph ordinates or flowrates at particular times must be entered in the text boxes labelled Time mins and Flow cu m s The graph assists the entry of data by providing a visual guide Specific ordinates can be located and altered using the arrows in the spin box associated with the times Pit Inflow Hydrograph Hydrograph duration mins 45 Hydrograph specified in 5 minute intervals 0 009 Time mins Flow cu m s 0 008 po p 0 0 007 0 006 0 005 0 004 0 003 0 002 Comments 0 001 Flow enters Atthe surface Flow cu m s 0 5 10 15 20 25 30 35 40 45 Time mins Figure 2 9 User Provided Inflow Hydrograph for Pits Hydrographs can als
144. I floods but PMP may need to be considered in developments where occupants are vulnerable such as child care centres or nursing homes A 4 Assessing Models and Inputs A 4 1 General One of the first issues for the reviewer is to determine whether the model applied is adequate for the task Guidance can be obtained from Australian Rainfall and Runoff 1987 and other manuals but these are often out of date Thirty years ago calculations were generally performed by hand on calculations pads Now computer models are now likely to be used in all but a few cases These can perform such a volume of computations that checking the arithmetic is impossible so reviewers must consider matters external to the actual calculation process such as e the capabilities of a method or program e its suitability for modelling the situation to which it is to be applied and e the validity of the parameters used in the model DRAINS offers a choice of four types of hydrological model to generate flowrates and two types of hydraulic model to calculate flow characteristics These cover most of the tasks required in urban stormwater practice A 4 2 Rainfall Inputs a General The main input to hydrological models is the design rainfall information provided by the Bureau of Meteorology This is based on older records and is being renewed as part of the current revision of Australian Rainfall and Runoff For the present the design rainfall information
145. IF File Marne ay Recent Places File name Oldtown Services mif Files of type Mapinfo MIF Files mif Figure 3 13 Choosing a MIF File As with the ESRI transfers with this setup it is possible to import a new or additional background Using the File gt Import gt Import DXF background option brings up a dialog box from which a DXF file can be opened When a file is selected the following window appears When a choice is made the background is replaced Add to or Replace Existing Background n ou can either replace the existing background layer or add the imported data to t You should only add to the existing layer if the new background ts different eg adding contours to an existing layer containing property boundaries Replace existing background CO Add to existing background 3 2 5 ILSAX File Imports DRAINS is partly based on the ILSAX program that was used widely in Australia since 1986 Many Government organisations developed ILSAX files describing their drainage systems that could be converted to DRAINS files using the Import ILSAX Files option in the File menu However there have been changes to DRAINS that mean that now it is hardly worthwhile to make transfers by these means These changes include the use of a different type of pit inlet capacity relationship and the omission of the ILLUDAS type pit that was employed in the transfer refer to the DRAINS Help system It is
146. If another run is made and the process is repeated with one of the existing shapefiles nominated in the Save As dialog box additional results will be appended 3 5 6 Hydrograph Outputs in TUFLOW Format Using the File gt Export gt Tuflow TS1 Sma Files option you can export hydrographs in a format used by the 2 dimensional DRAINS has created 3 ts1 files 3 per storm eg C Temp Set 2 Pipes 5 TUFLOW hydraulics program BMT WBM A year 25 min tsl C Temp Set 2_Channels_5 year 25 min ts1 and 2010 Hydrographs are produced for sub C Temp Set 2_Catchments_5 year 25 min ts1 catchments pipes and overflow routes for all storm runs made prior to exporting This format can be read by spreadsheets and editors and can be used by other programs than TUFLOW When a transfer is made the message to the right appears 3 5 7 Outputs to Linked Applications As part of the dedicated links from Autodesk Land Desktop Advanced Road Design and 12d to DRAINS results are transferred back to these applications via database files and the spreadsheet outputs as described in Section 0 and Section 3 2 7 3 5 8 Merge Outputs and Inputs The merge options allow you to add DRAINS systems together It is first necessary to export a system as a merge file before importing it into another system The two systems are linked the pits at each end of a common pipe which is the lowest pipe in the system to be added The procedure is as follows
147. L Class 4 Box Culverts Polyethylene black pipe Remove Nom Diameter mm Add Remove Froperties OF Cancel Pipe Type _ Name Folyethylene black pipe Minimum Cower mm BOO Colebrook White k mm 0 03 Manning s r 0 009 Hint IF you are using the Colebrook white equation simply accept the default value for Manning s n and VICE YETA f Circular Rectangular Cancel Norninal Diameter mm 225 Internal Diameter mm 213 Cancel Wall Thickness mm Min Slope 72 Trench Width mm Figure 2 76 Main Pipe Data Base and Pipe Type Property Sheets Import DRAINS Data Base File DB Pit Data Y Append to Existing Data C Replace Existing Data C Ignore New Retain Existing Data Fipe Data Append to Existing Data i Replace Existing Data Ignore New Retain Exisiting Data Overflow Route Cross Sections Append to Existing Data a Replace Existing Data i Ignore New Retain Existing Data DB 1 files contain pit data pipe data and owerfow route cross sections You can treat this data in various ways by setting buttons on the left Replace Existing Data is greyed out because there are pipes pits or overflow routes drawn You need an empty drawing to be able to use this option Figure 2 77 Dialog Box for Importation of Additional Pipe Pit and Overflow Data DRAINS User Manual 2 49 November 2014
148. MENT DETAILS 17 Name Pit or Total Paved Grass Supp Paved Grass Supp Paved Grass Supp Paved Grass Supp Paved Grass Supp LagTime Gutter Gutter 18 Node Area Area Area Area Time Time Time Length Length Length Slope Slope Slope Rough Rough Rough orFactor Length Slope 19 ha min min min m m m m 20 CatA 1 PitA 1 0 772 35 65 0 S 12 0 1 21 CatA 2 PitA 2 0 08 80 20 0 2 5 3 0 22 CatA 3 PItA 3 0 061 80 20 0 2 5 3 0 Sub Catchment Data 23 CatB 1 PitB 1 0 593 55 45 0 8 13 0 24 CatC l PitC 1 0 411 60 40 0 6 10 0 Pipe Data 25 26 PIPE DETAILS 27 Name From To Length U SIL D S IL Slope Type Dia I D Rough Pipels No Pipes ChgFrom AtChg Chg RI Chg RL etc 28 m m m mm mm m m m m m 29 Pipe A 1 PitA 1 Pit A 2 17 4 31 304 31 13 1 Concrete 450 450 0 3 New 1 Pit A 1 0 30 Pine A 2 PitA 2_ PitA 3 76 1 31 1 29 608 1 96 Concrete 450 450 0 3 New 1 Pit A 2 0 a te M 4 gt gt Sheeti Sheet Sheet3 lt J lid gt f Ready PJ Count 501 ERO 100 z Figure A 4 Spreadsheet Output of Data for the Gymea Model Usually similar names are given to a pit the sub catchment draining to it and the pipe and overflow route carrying water away from it Overflow routes are an essential part of the model being used to check that surface flow widths depths and velocities are not excessive Even where overflows are required to be zero a route should be included to demonstrate that this is so You will not
149. NTION BASIN DETAILS 113 Name Max WL MaxVol MaxQ Max Q Max Q 114 Total Low Level High Level 115 Basin 7 701 54 0 1 408 0 386 1 022 116 117 CONTINUITY CHECK for AR amp R 2 year 30 minutes storm average 54 mm h Zone 3 118 Node Inflow Outflow Storage Ci Difference 119 cu m cu m cum 120 Pit B 1 162 25 162 32 0 0 121 Pit B 2 176 77 176 43 0 0 2 122 Pit B 3 294 38 294 35 0 0 123 Pit B 4 320 25 319 79 0 0 1 124 Pit B 5 456 59 456 59 0 0 125 Pit B 6 745 04 744 85 0 0 126 Pit B 7 827 98 827 02 0 0 1 127 N 3 2311 29 2310 42 0 0 128 N4 3078 98 3078 35 0 0 129 N5 3598 65 3583 92 0 0 4 130 Cul 6 3777 55 3770 04 0 0 2 131 Basin 7 4095 65 3639 16 456 7 0 132 N7 3639 16 3627 44 0 0 3 133 Bridge 9 4288 66 4284 68 0 0 1 134 N 9a 4284 68 4277 03 0 0 2 135 N 9b 4277 03 4271 53 0 0 1 136 N 9c 4271 53 4248 23 0 0 5 137 Outlet 4248 23 4248 23 0 0 138 Pit C 1 222 03 221 72 0 0 1 139 Pit C 2 254 59 254 35 0 0 1 140 NO 145 19 145 13 0 0 141 Pit X 1 149 61 149 34 0 0 2 142 N1 1310 05 1309 65 0 0 143 HW 2 1454 84 1454 44 0 0 144 US C 1 0 0 0 0 145 US X 1 0 0 0 0 z 4 1 Data Minor lt Sheet3 3 W j Ready Z Average 311 3821232 Count 760 Sum 149152 037 0 m gt F Figure 3 45 Continuity Checks When a Design run is followed up by an Analysis run the results can also be transferred being pasted in the Major worksheet shown in Figure 3 45 These spreadsheets can be saved and used to document a design or analysis They can als
150. November 2014 File Edit Properties Basin Outlet Pipe Basin Only Volume cu m 0 e a ee 100 4 700 6 700 8 701 701 2 701 4 701 6 701 8 Elevation m Detention Basin Elevation Storage Relationship Display r File Edit Properties Critical Depth Elevation m 6 Distance m Irregular Channel Cross Section Display Figure 3 25 Sample Displays from the Pop Up Menus for Components Run Help Analyse major storms standard hydraulic model Analyse minor storms standard hydraulic model Analyse major storms premium hydraulic model Analyse minor storms premium hydraulic model Design Revise Pit Loss Coefficients Quantities b Help Analyse major storms standard hydraulic model Analyse minor storms standard hydraulic model Analyse major storms premium hydraulic model Analyse minor storms premium hydraulic model Analyse major storms basic hydraulic model Analyse minor storms basic hydraulic model Design Revise Pit Loss Coefficients Quantities I Figure 3 26 Run Menus for New DRAINS Models and for Older Models DRAINS User Manual 3 17 November 2014 If the premium hydraulic model is enabled by the hardware lock being used there are two more options d the Analyse major storms premium hydraulic model e the Analyse minor storms premium hydraulic model and if the model was created prior to the end of 2010 there are the options f the Analyse major storms basic hyd
151. November 2014 Home Insert Page Layout Formulas Data Review View Developer Acrobat AM31 6G fe 1 PIT NODE DETAILS D 4 Version 9 2 Name Type Family Size 3 a 5 PitB 1 Sag 6 PitB 2 OnGrade 7 PitB 3 Sag 8 PitB 4 OnGrade 9 PitB 5 Sag 10 PitB 6 OnGrade 11 PitB 7 OnGrade 12 N 3 Node 13 N4 Node 14 N5 Node 15 N7 Node 16 N9a Node 17 N9b Node 18 N 9c Node 19 Outlet Node DMR S Lintel DMR S Lintel DMR S Lintel DMR S Lintel DMR S Lintel DMR S Lintel DMR S Lintel 20 PitC 1 Sag Qld DMR S Lintel 21 PitC 2 OnGrade Qld DMR S Lintel 22 NO Node 23 Pitx 1 Sag Qld DMR Single Fie 24 N1 Node 25 HW2 Headwall 26 USC 1 Node 27 USX 1 Node 28 USB 1 Node 29 NB la Node 30 31 DETENTION BASIN DETAILS 32 Name Elev Surf Area Init Vol c Outlet Tyg K Dia mm Centre RL Pit Family Pit Type x y HED CrestRL CrestLen gid 233 Basin 7 700 5 34 701 1 35 701 4 0 0 1275 6170 4 gt gt Data Sheet2 Sheet3 1 4 Ponding Pressure Surface Max Pond Base Blocking x Bolt dowr id Part Full Volume Change Elev m Depth mjinflow Factor lid Shock Loss cum Coeff Ku cu m s 5 4 5 707 1 0 2 0 5 707 1 706 5 0 2 0 5 706 1 L5 705 3 0 2 1 705 3 0 5 704 5 704 3 703 5 702 5 701 4 701 700 6 698 699 5 706 2 705 8 703 4 705 3 704 8 704 2 706 3 705 5 707 2 706 9 0 5 211 798 101 767 No 181 1x Ku 0 227 558 101 833 No 182 1x Ku 0 5
152. O00 O00 O00 O00 O00 O00 aad aad Figure 5 36 TUFLOW TS1 Output Displayed in an Editor 5 47 November 2014 X A THE DRAINS VIEWER A 1 Introduction Written in a simpler style than the main manual this appendix describes how to use of the DRAINS Viewer which allows a checker to examine any DRAINS model submitted to them It has been prepared for persons checking or reviewing DRAINS models either internally within a design organisation or as a council officer or private assessor It also provides guidance to designers on choices to be made when setting up models and on information to be submitted for review Use of the free Viewer relieves reviewers of the need to check manually for numerical errors in tables or spreadsheets submitted for approval A DRAINS model can be submitted to the reviewer as a drn file with included results The reviewer can then inspect the model using the Viewer and concentrate on the suitability of the selected inputs and the resulting flows and flood levels knowing that results have been reliably calculated by DRAINS A 2 Setting Up and Running the Viewer The free installation file named DrainsViewerSetup execan be obtained from Bob Stack on 02 6649 8005 or bobstack watercom com au To install the Viewer on any PC running Microsoft Windows run the file exe and follow the instructions that appear Once installed the DRAINS Viewer can then be opened from the Start menu by selecting Programs and th
153. Paved Grass Supp LagTime Gutter Gutter 19 Node Area Area Area Area Time Time Time Length Length Length Slope Slope Slope Rough Rough Rough orFactor Length Slope 20 ha min min min m m m m 21 Cat4 Pit4 0 35 75 20 5 9 15 1 0 22 Cat5 Pit5 0 02 90 10 0 2 3 0 0 23 Cat1 Pit1 0 125 28 67 5 8 13 J Sub Catchment 24 Cat 2 Pit 2 0 231 33 62 S 9 15 1 Data Data for 25 Cat 3 Pit 3 0 025 90 10 0 3 4 0 Pipes 26 27 PIPE DETAILS 28 Name From To Length U SIL D S IL Slope Type Dia I D Rough Pipels No Pipes ChgFrom AtChg Chg RI Chg RL etc 29 m m m mm mm m m m m ee cen 30 Pine 4 Pit4 Pit5 12 03 21 169 20 769 3 33 Concrete 300 300 0 3 New 1 Pit4 0 fF 4 gt gt Data lt Minor lt Major lt 3 Mirm ag 100 ual Ready Figure 1 33 Spreadsheet Output for Data The flowrates are now larger and some overflows occurring These can be inspected using the Cross Section Data page of the Overflow Route property sheet as shown in Figure 1 36 With the standard hydraulic model these characteristics are based on normal depth calculations The premium hydraulic model calculations apply a more rigorous and accurate unsteady flow analysis The suitability of the overflows during minor or major storms can be assessed and the system enlarged if flow characteristics such as widths exceed acceptable limits DRAINS User Manual 1 21 November 2014 x H I 7 Booki Microsoft Exce
154. Pipe x 1 Pits CORK OF B 1b Pipe B 4 Y Chni 1 CatD1 s Pit D 1 7Pi 4 Pipe D 1 JOF DA j Cat D 2 ho CatB 5 OF D 2 lt RA PapipeD 2 Hw 2 Cad bata ES fl ii Pipe BKA PitE 2 Pipe C 2 Pit 8 57 tis TAL gE US TT rene Ee RPT on i ee ABSA pia Pipec eee OFB5 PitB 6 f a OF C 2 Pipe B 6B Tit 27 OF CA Outlet2 Ride B 7 ae Cat 3 i N3 a F n Press F1 for help Figure 3 61 The Combined File Both models should than have two common pits and can then be joined using the merge procedure described earlier in this section If necessary the background can be replaced using the procedures described in Section 3 2 2 b A problem may occur if there is a conflict in the id numbers that are used by DRAINS for internal purposes and which appear in the spreadsheet output Contact Watercom Pty Ltd if this occurs 3 5 9 Template File Exports To assist in the preparation of files that can be used as the basis of other models DRAINS has a function implemented by selecting File Export gt Drains template file This opens the following window After selecting a file type and clicking the Next button a window appears allowing the file name and path to be nominated and it can then be saved Export Drains Template File nem File Type DRN DEL Note A DRN file is simply the current job minus all pipes pits etc It contains all the current hydrological models rainfall data and pip
155. Plot style Pyotr ah y Pit style table None Piat table aached Modal ajo Met toble type Hoi ewoiloble C3 E View Hr Cemer X Br m r Y A Pa emer i Width Mic LESS boon On Yas ICS icon at origin Wo WS Name f omand 137 646E Ire raii SHAR GAID ORTHO POLAR CnaP OT MODEL Figure 3 37 Drawing Transferred Out of DRAINS in DXF Format A longitudinal section can be exported by nominating a path between neighbouring pits and then specifying drawing characteristics The option Export gt DXF Long Section in the File menu opens the dialog boxes shown in Figure 3 38 Export DXF Long Section Step 1 Select a route From pit Pit 6 1 To pit for node NJ Cancel es portirig ari ti relative sizes tees Figure 3 38 Dialog Boxes for setting Paths for Plotting Long Sections The smaller box is used to define a continuous pipe route You need to specify the starting and ending node names exactly allowing for blanks and the case of words Once a route is selected and the Next button is clicked a preview like that shown in Figure 3 39 appears This is in a window that can be enlarged by clickin on the Maximize button circled at the top right of the window The Customise button opens the dialog box shown in Figure 3 40 which can be used to set drawing features Changes are reflected in the preview DRAINS User Manual 3 24 November 2014 Long Section Drawing Preview Ebit Pit Ba AS
156. R 2 year 1 hour storm average 29 4 mm h Zone 1 File Edit Properties 0 018 HGL m 53 67 Results of Standard Hydraulic Analysis Time mins Figure 3 34 DRAINS Results showing Main Window Hydrograph and HGL Plot Windows 3 5 2 DRAINS Print Diagram Option DRAINS has a facility for printing out the system displayed on a screen either completely or as the view shown on the screen This is implemented in the Print Diagram option in the File menu using the dialog box shown in Figure 3 35 Font sizes can be altered The OK button starts the printout while the Setup button opens a Printer Setup dialog box In the past this facility has not worked with some printers due to problems with printer drivers Trying the options now available should produce a satisfactory image Another way around printing problems is to print to a pdf file if you have Adobe Acrobat or another program capable of doing this and then to print from the pdf file 3 5 3 DXF Exports Printing to FX DocuPrint C1110 B PCL 6 Copy EEs pE O Full diagram Current window only Cancel Vector image Help C Raster image Note On some printers vector images look better on others the reverse is true Font Scaling Factor 1 Mote Ifyou are not satished with the printer font pou can Use a larger or smaller font by specifying a Font Scaling Factor larger or smaller than 1 This Factor
157. Run optional 4 Vary File and Run the Variations 7 Send DXF File to Drawing Program to Produce Design Drawings 4 Complete Documentation Figure 4 11 The Design Process Using CAD and DTM programs catchment areas can be defined as polygons and the areas directly measured The lengths of flowpaths and in some models their slopes can also be determined In some models the automatic definition of impervious and pervious areas will be possible where suitable overlays are available DRAINS User Manual 4 12 November 2014 For convenience in design the parts of the system can be separated into small sub systems For example where several branched pipe systems in steep terrain flow to a common open channel the pipe systems can be analysed independently as long as there are no backwater effects In flat terrain with backwater influences the system must be designed as a whole Individual systems can be joined using the merging procedures described in Section 3 5 8 DRAINS produces information on pipe sizes invert levels and locations that can be transferred to drawing programs to produce detailed plans and longitudinal sections The spreadsheet tables act as documentation that can be printed or supplied in electronic form to a consent authority together with the DRAINS data files Diagrams of the network can be printed say as a PDF file using the File Print Diagram option Models and results can be checked by persons inside o
158. S model to estimate surface flows approaching pits and the outlet 40 For sub catchments there may be two rows of information covering full area and partial area results 41 There may also be multiple rows for overflow routes coming to a pit Up to three are permitted 42 Depending on inputs the table may show results for a minor storm a major storm or both 43 Since certain outputs of DRAINS do not exactly match those in the rational method calculations that the chart was originally designed for 44 gt gt i Check Minor Check Major QUDM Sheet _ BCC Sheet PRSC Sheet AJ A Ready g Figure 3 48 Rational Method Converter Results Data for pipes pits nodes and sub catchments can be transferred back into DRAINS using the Paste Data from Spreadsheet option in the Edit menu You must first make the required changes and then copy the entire spreadsheet to the Clipboard using the Copy option in the spreadsheet A quick way of selecting an entire Excel spreadsheet is to click the cell top left cell between the 1 and A cells The changes can then be pasted into DRAINS using the Paste Data from Spreadsheet option in the Edit menu Because the transfers are made via the Clipboard it is not necessary to have any direct connection between the spreadsheet file and the DRAINS file A similar output spreadsheet using ILSAX hydrology can be obtained from Geoffrey O Loughlin at geoff oloughlin tpg com au 3 5 5 GIS File Exports
159. Systems ccccccseeeeeeseeeees A 14 A 4 5 Pipe Pit and Overflow Route Data Bases ccccccceccccceeceeeeeeeeseeceseeeeeseeeeeaeeeeseeeesseeeeees A 18 AAG WAY CAM GS 2s ats hsata ned dition lsat theat a a a onda paesusadaaesnace sees aatiemnaeaeny A 19 A 5 Checking Model Components Flowrates and Water Levels 000 A 21 A 5 1 Viewing Pipe System COMpone ntts cccccccsssseccceeeeeccaeeeeesceaeeessegeeeseeeeesseaeeessaeeeessaaeees A 21 A 5 2 Viewing Pipe System Results ccccccsssseeceesseecceseeeceeseecseueeecsageessegseesseuseesssageeessageees A 22 A 5 3 Reviewing Stormwater Detention and Retention Systems ccccccseeeeeeeeeeeeeeaeeeeeaeeeees A 26 Reviewing Open Channel Systems cccccccccccsseeeceseeecceeseeecsaeeeceseeeseageeessageeesseseesseageessageees A 29 PO PAMAIV SOS 255 xaasasict anata tiseaas N A 29 Al 0 90 gt lt 0 9 ipemer renner tne he ert he ae ae era ae eter eter Pee ear eee eee eee ener ee perenne A 30 REFERENCES INDEX DRAINS User Manual iv November 2014 Xg WELCOME This manual available in both printed and electronic forms provides the information you need to run the DRAINS program to design and analyse urban stormwater drainage systems Together with the Help system that accompanies DRAINS it will guide you to understand what DRAINS can do and how to use it to model many situations The data files included in the Manual Example Fi
160. T C x log T D x log T E x loge T F x loge T G x log T Te Time in hows and intensity in millimetres per hour YEARS A B c D E F G WEARS A 1 23004064224 65660650E 1 lt 4 0461913E 2 1230132062 3 7275700E 5 7 86326306 4 8 7156179E 5 gt 68627103939 6 6004133F 1 405627380F 2 1 10711106 2 1779313084 6 3637685E 4 5 4575454E 4 3 015918084933 6 7267632E 1 4 0390953E 2 10904536E 2 2014783064 5 9101160E 4 47363595E 5 10 3 1986677647 68044913E 1 4 0136363E 2 1 1063804E 2 1687306084 5 91051656 4 4 6390454E 5 20 3 4009633084 6 BRO4064E 1 3 99800865F 2 10486 1426 2 2 30087 108 4 A S13897E 4 3 3599779F 5 50 36403150558 6 9470477E 1 3 9279275E 2 1 1232489 2 3 6150700E 5 5 B430096E 4 5 0596672E 5 100 380782600422 7 0012963b 1 3 91719314E 2 1 12853368 2 1324110065 5 83564406 4 5 113 878r4 Mew Gate 1533 7262 001 34 45 551 1 24 Saet 66 F2e4 46 Feta OH Australan Gowermmect Muresu of Meteorology Copy Tattle 10 _ 17 a eee _ 7 E p EO y S i Figure 2 69 I F D Coefficients Paste BOM format table C You can paste a table of IFD data in either of two BOM Bureau of Metoeorology formats The table of coefficients is recommended if you are using data from BOM because you are not limited to BOM storm durations e g 25 minute storms are possible The IFD table format is recommended if you are using non BOM e g Council d
161. These equations allow for inlet control where the constriction at the opening of the culvert is the determining factor and for outlet control where a high tailwater level and significant head losses make the conduit flow full In DRAINS the flowrate and the downstream water level at each time step are established and the corresponding headwater level is determined using the above equations When either of two equations can be used because there are two possible states of flow the equation giving the highest headwater level is selected A considerable amount of information on road culverts is available from the US Federal Highway Administration in manuals and software available at www fhwa dot gov bridge hyd htm Mays 2001 also provides considerable information on culverts 5 9 2 Bridges Bridge hydraulics is particularly complicated because it is necessary to allow for the transitions from a broad channel cross section to a constricted bridge cross section and back to a channel section The bridge abutments piers and possibly the deck can all obstruct flows Hydraulic expertise is required to interpret results The U S Federal Highway Administration has published methods by Bradley 1970 which have been used in the AUSTROADS waterway manual 1994 More extensive procedures are incorporated in the HEC RAS computer program Hydrologic Engineering Center 1997 You are referred to these references for further details DRAINS covers relativ
162. Urban and residential areas where SiS average and slope is between 10 and 15 s e ILSAX Loss Models Losses from paved and supplementary areas are calculated simply in the ILSAX model Depression storages are considered as initial losses subtracted from rainfall hyetographs prior to time area calculations The general range of depression storages is from 0 to 2 mm for impervious surfaces and 2 to 10 mm for pervious surfaces Commonly used values for paved supplementary and grassed areas are 1 1 and 5mm respectively Dayaratne 2000 recommends values of 0 to 1 mm for impervious areas The procedures for grassed areas are more complex They are based on the general equation developed by Horton in the 1930s f fe fo f e Equation 5 5 where fis infiltration capacity mm h fo and f are initial and final rates on the curve constants mm h k is a shape factor here taken as 2 h and tis the time from the start of rainfall minutes DRAINS User Manual 5 9 November 2014 This describes the curves shown in Figure 5 9 These only apply when there is sufficient rainfall to satisfy completely the infiltration capacities and accumulated infiltration is increasing at its full rate 250 Antecedent Moisture 200 Condition CAM we Starting Points ty 150 1 p 100 Infiltration Capacity mmh 0 40 oL 120 Time after Start of Storm minutes Figure 5 9 Horton Infiltration Curves The curves represent soi
163. Watercom Pty Ltd DRAINS User Manual A manual on the DRAINS program for urban stormwater drainage system design and analysis by Geoffrey O Loughlin and Bob Stack This manual coincides with DRAINS Version 2014 11 It is available electronically and on paper and is updated regularly to download a PDF file of the latest version visit www watercom com au Sydney November 2014 Xa CONTENTS CONTENTS WELCOME 1 INTRODUCTION TO DRAINS Mee E o a E E E E E 1 1 Mise Do CIPON e e E ES 1 1 1 1 2 Modelling Aspects pesca feneictecnnanadainut annsietarsunt adieu tesinddiew Svaycicwrunbddawilioneddvincentddvalassadnawgereidenenndasenaws 1 2 e IPS ie COMMET ASPEC aa E ne ee ee ee eee 1 4 Mig U ge OOF ashe x eine E lt suet sdnteceesenendeescedeneuc ane E E E A 1 4 kto WAS UCN OU cocaine sajetn aamavicisanaisodceennededinanaitenencuiiaadensasattinnaatsatansvanadesaeabedawncehaduapesaunnencuehasaanaucieaseduainsstins 1 5 DNs SoU EMG OO siccsce tae acion E EE N E E E E 1 5 1 2 Examples of DRAINS in Operation sicisrcisarerericartiaviacreeceinereaeekaricaniaereeemenreeent 1 5 1 2 1 Running a Model of a Simple Pipe System 1 0 00 cccceceeeceeeeeeeseeeeeeeeeeeeeseeeeeesaeeeesseeeeeesaees 1 5 1 2 2 Running the Rational Method and Extended Rational Method Models cceeeeeeees 1 23 1 2 3 Running the Premium Hydraulic Model cccccccccseeeeeeeeeceeeeeeeeeeeeeeeeeseueeeeeeeseneeeseeeenaes 1 26 1 2 4 Running Sto
164. X locations of the left and right banks that divide the zones of different roughness m With the standard and premium hydraulic models the data shown in Figure 2 57 must be entered in the second page of the property sheet This provides instructions on choosing the values to be entered DRAINS User Manual 2 35 November 2014 Bridge Properties Simpified Flow Properties Name Bidge9 OO Deck top level 7022 Weir coefficient foo j om tn dm bo Ao 45 degree wingwall 30 degree wingwall ae Comments Pier Type C HHHHH Five square Five circular Two square r Main Channel Two circular Left Bank Xcoordinate 1 A same pee Sie Aight Bank Xcominate 10 Round end dumbell Figure 2 55 Bridge Property Sheet Reference Channel Pier in Trapezoidal Channel Pier and Right Bank Abutment in an Irregular Channel Figure 2 56 Pier and Abutment Locations Bridge ax Properties Simplified How Properties The standard and premium hydraulic models use simplified theory for bridges to speed up calculations They assume headloss is proportional to velocity squared The values you provide here are used to develop rating equations that are used in the calculations Hint We recommend you do an analysis using the basic model to estimate the values below Expected maximum flow c
165. XXXX optionally one or more velocities from different storms For information on the other four components you can refer to the formats of exported MapInfo files reading the MIF file with a text editor Note that all numbers are exported as text and not as numbers They will need to be converted in Maplnfo if attributes are to be used as the basis for colour coded plotting 5 10 4 Spreadsheet File Formats DRAINS transfers data to spreadsheet programs in the space delimited ASCII format shown in Figure 5 35 This appears in cells when opened in a spreadsheet program as shown in Figure 1 33 DRAINS User Manual 5 46 November 2014 Ej Document WordPad 5 x File Edit View Insert Format Help Dice ale a el S PIT 7 NODE DETAILS Version 6 Name Type Family Size Ponding Pressure Surface Max Pond Base Blocking x y Bolt down id Volume Change Elew im Depth m Inflow Factor lid icu m Coeff Ku cu m s Pit B 1 Sag Qld DMR Gully Pit both 0 25 2 grade S Lintel 5 4 5 707 1 0 2 m 0 2 211 798 101 Pit B 2 OnGrade Qld DMR Gully Pit both 0 25 2 grade 5S Lintel 0 5 707 0 0 0 2 227 558 Pit B 3 Sag Qld DMR Gully Pit both 0 25 2 grade S Lintel 5 1 0 706 5 0 2 o 0 2 287 099 101 Pit B 4 OnGrade Qld DMR Gully Pit both 0 25 2 grade 5S Lintel 0 5 706 1 0 0 2 290 690 Pit B S Sag Qld DMR Gully Pit both 0 25 2 grade S Lintel 5 1 5 705 3 0 2 m 0 2 290 762 1 2 Pit B 6 OnGrade Qld DMR Gully Pit both 0 25 2 grade 5S Linte
166. a 1981 y ILSAX Australia 1986 Y PIPES DRAINS Australia 1998 Figure 5 1 The Initial Development Path of DRAINS The TRRL method was developed by Watkins 1962 following extensive studies in which storm rainfalls and runoff were recorded for several years on twelve catchments Flow estimates from the rational method and other hydrological models were compared with the recorded data A design procedure using the time area method Ross 1921 applied to impervious areas was developed from this research UK Transport and Road Research Laboratory 1976 A simple procedure was applied to route flows through pipe systems This was released as a FORTRAN program in 1963 replacing the rational method The Illinois Urban Drainage Area Simulator ILLUDAS was developed and extensively tested by Terstriep and Stall 1974 who adapted the TRRL Method to cope with pervious area runoff and added other features Tests involving gauged data from 21 catchments were made Although ILLUDAS was popular among researchers it has not been widely used by designers in North America For most design tasks ILLUDAS and SWMM Stormwater Management Model have been overshadowed by U S Soil Conservation Service programs TR20 and TR55 and other relatively simple methods After testing ILLUDAS on two South African gauged catchments Watson 1981 produced a version named ILLUDAS SA with many additional features This was the basis for the ILSAX program In
167. a Exporting ESRI ArcView Arcinfo ArcMap Files It is first necessary to establish a system that is capable of being run such as the example shown in Figure 3 49 DRAINS User Manual 3 30 November 2014 Selecting the ESRI Shapefiles option from the File gt Export menu presents the message shown to the right If you continue you will then need to nominate a filename for shapefiles in the dialog box shown in Figure 3 50 You can see from the existing files in this example how six ESRI SHP files are established Another 12 SHX and DBF files will also be produced After a name is entered the process is complete if there are no results If results are available the dialog box shown in Figure 3 51 appears A suitable name DRAINS You are about to export data to a set of 6 ESRI shapefiles These include data for nodes including pits etc pipes pipe survey data services crossing pipes catchments and overflow routes Each shapefile comprises a set of 3 files with the extensions SHP SHX and DBF so that a total of 18 files will be used You can select any one of these existing HP files and DRAINS will update all 18 files Or you can enter a new name and DRAINS will create 18 new files based on variations of that name eg enter MyJob to create MyJob_Pipes shp etc The next step is to specify the file name Continue should be added describing the results here they are for a 2 year average recurrence interval
168. a Initial Logs mm Pervious Area Continuing Loss mmh Figure A 14 Model Property Sheet for a RORB Model The data bases selected should obviously reflect the conditions at the site Users can create their own pipes pits or overflow routes by adding information to the data bases In analysing existing systems this may be necessary because a pit may be an obsolete type for which no inlet capacity information is available A Generic Spreadsheet for Pit Inlet Capacities provided on the accompanying CD can be used to establish relationships for these pits Where inlet capacity is an important consideration details should be provided with any design or analysis documentation A 4 6 Hydraulics Designers apply hydraulic methods to determine flow characteristics corresponding to hydrological flow estimates These characteristics water levels depths widths velocities and products of depths and velocities are used to decide whether the flow is being conveyed safely along a pipe or channel There has been rapid development of hydraulic models recently particularly 2 dimensional models of surface flows Table A 13 and Table A 14 provide a classification of models with examples of the software used in Australia The first two types in Table A 13 are procedures that can be implemented with a calculator while the others are packages that organise large amounts of data describing the geometry and characteristics of pipes channels and flow paths
169. a background is present in the DRAINS model this will be transferred with the ESRI files The transferred files can now be viewed in ArcMap as shown in Figure 3 52 En fda sia echoes Wa peleen Took Window Help oes E gt me F 2 amp Oe 2 ae U ee A k Salag S a Gymea Catchments DE GyreaNodee a BA ymer Services ie Gpmtiea Surery BE Cymer Coed Rout fA ymer Pipes mE Grmi Greup Liri Dreeng Rol oe OF AT T am al HF u AT he EAE AFGR LTSOGS8 TDG Urikiri Wabi Figure 3 52 Display of Results in ArcMap A database table is associated with each theme as shown in Figure 3 53 Note that most values are specified as strings of characters and must be converted to numerical values using procedures within ESRI programs if these are required to provide thematic displays where colours line thicknesses or other attributes indicate properties Sutherland 3 crossfall all slopes kerb inlet with 0 85 m lintel 3 crossfall all slopes N A 5 308 wa Jo Jo N k 3 Point er F ses Sutherland 3 crossfall all slopes kerb inlet a 3 crossfall all slopes 20 5 30 9 0 2 ei ae i WA OBE ml DH cease aspes WA E 307 wa Jo lw EE kerb inlet with 0 85 mintel 3 crossfal alsiopes WA os 323 ma fo f PRAT tSas Sutherland 3 crossfal allslopes kerb inlet with 18 mintel 3 crossfal alsiopes 30 s 325s 03 b 08 Ne 2m
170. a free outfall of the type commonly used in on site stormwater detention OSD storages in Sydney DRAINS User Manual 2 22 November 2014 Detention Basin Data Initial Water Level Infiltration Data Name Basin 7 Bev Surf Area im isq m 700 5 0 701 1 1275 701 4 6170 701 7 17760 701 8 19000 701 9 20000 Low Level Outlet Type connecting to a pipe C Orifice Kentry Kbends 0 5 C Pit Sump f Circular culvert C Rectangular culvert f None 2 3 4 5 6 f g Paste Table Note The prismoidal formula is used to calculate volumes from suface areas Click Help for more details High Early Discharge Notes Figure 2 33 Detention Basin Property Sheet with Elevation Storage Relationship e apit or sump outlet e a circular conduit the example shown above e a rectangular channel similar to the circular outlet and e no low level outlet These are then selected and the Edit Copy option is used to place the data on the clipboard Transferring from the spreadsheet program to DRAINS the data can be entered using the Paste Table button For pipes it is only necessary to specify the entry and bend losses as shown in Figure 2 32 The rest of the information is included in et gt the property sheet for the outlet pipe This is the same as the sheet py lass coefficient K Hg for a pipe located between pits as shown in Figure 2 12 except that there is provision for an exit
171. age recurrence interval ARI such as 100 years The arrangement and sizes of channel segments needs to be refined by trial and error to achieve the best result The required checking documents are set out in Table A 4 Table A 4 Typical Requirements for Assessing Trunk Drainage Systems Plan view of trunk drainage system showing Survey set out information is often included locations of channels entry points of pipes along the channel and features such as drops and culverts Channel long section profiles and cross 100 year ARI water surface profiles might be sections shown Plans and sections of special features such as bends junctions and culverts Design report Detailed calculations are not provided because computer models are used but results in the report show water surface profiles and indicators such as velocities and freeboards General practice for subdivision design is to prepare an initial trunk drainage master plan defining the sizes of channels and detention facilities that need to be provided and the land area required to accommodate these As detailed design proceeds these estimates are modified Design ARIs are 100 year ARI with probable maximum precipitation PMP estimates required where the potential consequences of failure are severe A 3 6 Localised Flood Studies Where developments or re developments are located along flow paths or in areas that may be flooded due to water ponding downstream obstruction
172. ags A modular system built around one or two pits with grates A modular system made up of pits C and troughs T Nominally for sags only but an on grade relation assuming 1 grade is included Table 5 17 Relationships for Western Australian and Tasmanian Pits derived using US Federal Highway Administration HEC 22 procedures are shown in Table 5 18 and Table 5 19 For both on grade and sag pits a choke factor can be applied to simulate blockage of the pit This is 0 0 for no blockage and 1 0 for complete blockage There is considerable uncertainty about appropriate factors Australian Rainfall and Runoff 1987 indicated typical values of 0 2 for an on grade pit and 0 5 for a sag Some Queensland practice applies values of 0 1 for both It could be argued that a factor of 0 0 should be applied to on grade pits which are much less likely to block than sag pits These are multiplied by the capacity defined by the inlet capacity relationships whatever magnitude this may be While this is acceptable for the type of blockage that might occur for sag pits it may not be realistic for on grade pits If you have doubts about this it would be better to define the required inlet capacity relationship in the pit data base and to employ this with a blocking factor of zero DRAINS User Manual 5 26 November 2014 Table 5 17 South Australian Pits Source html files developed by the Urban Water Research Centre of the University of South
173. ainage Pit Property Sheet for an On Grade Pit Second Page The original blockage calculation process in DRAINS simply multiplied the inflow capacities for an on grade pit by a constant blockage factor The same percentage reduction applied for low and high approach flows The blocking theory that is now applied results in a lower reduction at low approach flows and an increasing blockage effect with increasing flowrates up to the specified factor An further explanation is shown in Figure 2 5 Queensland DMR Pit with Lintel 3 crossfall and 2 slope or less Inflow rs 0 0 2 0 4 Ub 0 5 1 2 Approach Flow ims Figure 2 5 Inlet Capacity Relationships allowing for 0 5 50 Blocking Factor In older DRAINS models the method to be applied could be set in the Options property sheet Figure 1 12 A pit can be excluded from the design process using the This pit is buttons at the bottom left of the property sheet c Sag Pits For sag pits the Drainage Pit property sheet appears as shown in Figure 2 6 Itis necessary to enter the same information as for an on grade pit with additional data required for water that might form a pool over the pit It is necessary to specify the maximum ponded depth and the corresponding volume of ponded water over the pit DRAINS User Manual 2 6 November 2014 Drainage Pit Pit Properties Pond Properties QUDM ei isa Baseflow Name Information Information for QUDM for sag pit determin
174. al pit is entered in the triple property sheet shown in Figure 2 79 The relationships are entered directly as tables This provides flexible relationships particularly at the top end of the curves It is possible to set an upper limit on inlet capacities if required As part of the DRAINS design method sets of relationships for pits in various regions have been provided in db1 data files contained in the C Program Files Drains ProgramorC Program Files x86 Drains Program folder under names such as NSW Pits June 2008 db1 Relationships for NSW Queensland Victoria the Australian Capital Territory South Australia and Western Australia are now available Instead of a single data base these are made up of sets of relationships that can be combined as required using the Import gt DRAINS Database DB1 File option in the File menu Via the dialog box shown in Figure 2 77 additional pit types can be entered into the data base This process can be assisted by the Paste Data and Copy Data buttons in the On Grade Data and Sag Data windows shown in Figure 2 79 The first function can bring in data from two columns of a spreadsheet in the same way as for rainfall patterns Section 2 4 4 The Copy Data function can transfer data to a spreadsheet or directly to another DRAINS pit data base A pit data base can be selected for a new project using the Default Data Base option in the Project menu in the dialog box shown in Figure 2 80 Through Wat
175. also be used to assess flood depths to be related to floor levels of existing or planned buildings The flow that is displayed in Figure A 24 may be greater than the rate displayed in the Main Window due to an additional flow being specified to allow for overflows combining with flows from the sub catchment through which they flow This occurs when the number in the box labelled of downstream catchment flow carried by this channel in Figure A 24 is greater than zero Refer to the Manual and Help system for more information Reviewers should note that when the basic or standard hydraulic model see Section 4 4 is used in DRAINS the flow characteristics in overflow routes are calculated by assuming uniform flow conditions along the overflow route In fact the flowrate will vary along the route If the premium hydraulic model is applied the water surface will be determined more accurately and it will be possible to display a long section as shown in Figure A 25 Therefore when the standard or basic hydraulics are used the flow characteristics should be considered as an indicator rather than as an accurate estimate Overflow route characteristics are also questionable for short routes and those running round corners Using additional spreadsheets included on the CD accompanying this guide the DRAINS spreadsheet outputs can be converted to tables of the form shown in Figure A 26 This is from the Gymea ILSAX example There is another that converts r
176. an Public Works Association Chicago Queensland Department of Main Roads 2002 Road Drainage Design Manual Part C Hydraulic Design Brisbane Available for download search for this title on the internet the URL is too long to quote Queensland Department of Energy and Water Resources 2013 Queensland Urban Drainage Manual 3rd Edition Brisbane Ragan R M and Duru J O 1972 Kinematic Wave Nomograph for Times of Concentration Journal of Hydraulics Division ASCE Vol 98 No HY10 October DRAINS User Manual R 2 November 2014 Rigby E H Boyd M J and VanDrie R 1999 Experiences in developing the hydrology model WBNM 8th International Conference on Urban Storm Drainage Sydney Australia Ross C N 1921 The calculation of the flood discharge by the use of time contour plan Transactions Institution of Engineers Australia Volume 2 pp 85 92 Ryan C 2005 CatchmentSIM A stand alone GIS based terrain analysis system CRC for Catchment Hydrology Melbourne wwww toolkit net au catchmentsim Sangster W M Wood H W Smerdon E T and Bossy H G 1958 Pressure Changes at Storm Drain Junctions Engineering Series Bulletin No 41 Engineering Experiment Station University of Missouri Shek J and Lao J 1998 Urban Rainfall Runoff Modelling at Hewitt Penrith Undergraduate Project Faculty of Engineering University of Technology Sydney Siriwardini N R Cheung B P M and Perera B J C 2003 Estimation of Soi
177. anual 2 34 November 2014 2 3 15 Culverts Initially culverts were modelled in DRAINS using the Culvert component a the concentrated all the functions of culverts into a single object This has now been replaced by the combination of a headwall with a pipe and overflow route as shown in Figure 2 54 and the culvert object has been removed from the DRAINS Toolbar This is similar to the arrangement used for detention basins 3 Toowoomba Estate drn DRAINS Pipe from HW 6 to N 6 S File Edit Project View Draw Run Help 5 n oe tl a gt EARE z u Pipe name Pipe 6 Pipe length m 8 J Ww s Upstream invert elev m 700 9 p 5 Pipe Type mae Headwall _ Box culverts Downstream invert elev m Slope 1 00 Name HW6 OK Width m x Height m K entry os ae 2x18 v Exit loss coefficient K 0 Overflow level m 705 1 Help No of identical parallel pipes 1 Include Non Return Valve Notes ___ Overflow Route OF 6 Pipe Roughness During C Use default value 0 3 mm 2 Basic Data Weir Data Cross Section Data A C ism You specify a we ise Name OF 6 AE E bana 15 Scale off Length aps Notes Travel Time mins 05 QUANTITIES Extra Data for Premium Hydraulic Model Excavation volume N A Upstream IL m 705 1 Downstream IL m 700 82 Notes Press F1 for help a He Figure 2 54 Culvert Constructed from Headwalls and Other Com
178. applies to a point just below Pit 1 If the percentage is set at 65 the flowrate displayed will be the overflow from Pit 1 plus 65 of the flow from Catchment 2 This sum is calculated from addition of hydrographs and represents the flow at a point just upstream of Pit 2 By varying the specified percentage between 0 and 65 we can define surface flows at any point along the flow path Using this feature you can examine the flows approaching pits at the top of a pipeline as shown below Cat act Although the overflow routes originate from a node with no connected sub catchment a percentage of the flows from sub catchment Cat A 1 can be specified and the flow characteristics along the flow path determined When applying the Design procedure DRAINS focuses upon the flow at the point defined by the specified percentage of the downstream catchment This can represent a critical feature such as a child care centre or bus stop that needs to be specially protected Note that this feature will only be meaningful on long overflow routes The flows calculated will not be accurate for short flow paths where the calculated normal depth cannot be established and paths across streets or around corners By changing the value in the box labelled Channel slope the slope can be varied along the entire flow path length to reflect a concave or convex longitudinal profile as opposed to a constant slope Overflow routes can be divided into several
179. are to be calculated using the Queensland Urban Drainage Manual QUDM charts refer to Section 3 4 4 These include an aligned misaligned choice explained in the DRAINS Help system and the width of the pit wall on which the outlet pipe is located DRAINS User Manual 1 12 November 2014 3 Untitled DRAINS n Edit Project View Draw Run Help E E 7 Open Close Sme Ctrl S Save s Import d Import DXF file Export ESRI Shapefiles Print Diagram Ctrl F sine hel acre LD File Se EELT Advanced Road Design File 2 Orangel drn 3 DRAINS Exercise 5 1 Answer HEC22 drn i 4 HEC22 drn Merge File S CATh Be i DRAINS Database DB1 File 6 G Temp Dubbo Template drn Gymea ILSAX Example Premium drn 8 Gymea ILSAX Example Premium drn Import Pipes and Pits from DXF File meme Pipes are on layer Pipes Pitt are on layer Pits circles r Background i on layer optional Background Mote Ifyou import a background layer you can change tts colour from the Yiew Background menu iter cocoi Hep Figure 1 18 Menu and Dialog Box for Nominating CAD Layers 58 Untitled DRAINS Sto File Edit Project View Draw Run Help Deju S clelals B ollue os als 4 For Help press F1 Figure 1 19 Inputted Drainage System from the CAD File From Figure 1 14 you can see that any overflows from Pit 1 will flow to Pit 2 so that this first pit should be sele
180. as shown to the right The left one should contain the times in minutes of BE 103 the start of each block beginning with zero The time divisions used must be the 70 3 same throughout they cannot be varied The right column should contain the DRAINS User Manual 2 47 November 2014 rainfall intensities corresponding to the given times in mm h This facility allows complex patterns such as that shown in Figure 2 75 to be entered You should copy both columns to the Windows Clipboard and then transfer from the spreadsheet program to DRAINS Clicking on the lt Paste button in the property sheet in Figure 2 74 will automatically enter the rainfall pattern This is an effective way of entering patterns for probable maximum precipitation and extreme flood modelling At times DRAINS may not calculate hydrographs for as long a period as you may require The calculation period can be easily extended by increasing the given storm duration in Figure 2 74 This automatically assumes that the extra rainfall ordinates are zero and extends the calculation period Rainfall Data Storm a a of d Name Storm of 20 June 1979 Avoca St Pluviograph Antecedent moisture condition 1 to 4 2 Annual Recurrence Interval pears n a Storm duration mins pro Rainfall specified in 3 minute intervals Time mine Intensity mmh 0 0te3 0 0 g Paste Intensity mm h Comments 200 300 400 Time mins Add one ARRS storm Add Synthe
181. asin Ready 7 Ee n Add an ARRAS Storm Add Synthetic Storm Add a New Storm Delete Current Storm Help Figure 3 6 Transfer of a PMP Rainfall Pattern from a Utility Spreadsheet to DRAINS Rainfall Data The transfer must include the files for nodes but the rest are optional In a first transfer it is unlikely that all the information required by DRAINS will be available in the GIS Information that is already in the GIS should be included in the files to be transferred You can then choose whether to add additional data in these files or to use dummy values and enter the required values later in DRAINS The example shown in Figure 3 illustrates the process The data for nodes including pits and outlets and pipes each contained in a theme needs to be entered in the data base tables shown in Figure 3 8 which can be created by editing in ArcMap or other GIS programs A DXF file containing a background for the DRAINS model can be created from GIS layers Untitled ArcMap ArcView BE h E z File Edit View Bookmarks Insert Selection Tools Window Help Oe FESS ESEE SlvM eorly QQrxur ed 8s kloumease AD x amp Layers O Oldtown Base dxf Oldtown Base dxf Ann Oldtown_Nodes ae m f Pw 24 9 Oldtown Base dxf Poin cess Paved Playground Grassed Playground Oldtown_Pipes R ifed Identify from lt Top mostlaye gt Z OoOO O O layer gt E Oldtown _Pipes i Pipe A 9 Oldtown Base d
182. at shown previously in Figure 1 8 Into this sheet you can enter the minor and major ARIs you require and the corresponding design rainfall intensities for durations of 6 minutes 1 hour 12 hours and 72 hours This information is available from Australian Rainfall and Runoff 1987 the Bureau of Meteorology s CDIRS procedure or from councils drainage design manuals or codes Updated information soon will be available from the Bureau of Meteorology s website www bom gov au DRAINS User Manual 1 24 November 2014 Rainfall Data for Rational Method OF ARI pears e 1 Hour Rainfall Intensity mmhour 24 6 ARR Wizard 12 Hour Rainfall Intensity mm hour 4 30 t Hour Rainfall Intensity mm hour re l Help Note The Intensities shown above are LPIll values obtained from the Bureau of Meteorology or Councils If these are not readily available you can use the ARR Wizard with values you read from Australian Aaintall and Aunott Volume 2 maps to calculate them Figure 1 40 The Rainfall Data for Rational Method Property Sheet The ARR Wizard button allows this information to be obtained from nine factors that can be found from Volume 2 of Australian Rainfall and Runoff 1987 These are entered in the property sheet shown in Figure 1 41 The intensities are calculated from this information and are used to establish the full intensity frequency drainage relationship used by DRAINS for rational method calculations TE
183. ata because you can set it up in a text editor use a BOM table as a template You can edit storm data e g add 25 minute storms remove unwanted ARIs For either table you should use the flash version on the BOM website to generate the table then press the Copy Table button on the BOM website You can edit the table in a text editor if required Then dick the Paste Table button below ART in years coefident A coefficient B coefficent C coefficient D coeficentE coeficier 1 2 9904964924 6 56650650E 1 4 04619 156 2 1 2501529E 2 3 7275 00E 5 7 863528 9 2 2 0862103939 6 60041535E 1 4 05623580E 2 1 1071110E 2 1 7793130E 4 6 36326 9 2 015918 4933 6 726 7632 1 4 0390953E 2 1 0904536E 2 2 0147830E 4 5 91011 10 3 1986677647 6 8044913E 1 4 0136363E 2 1 1083804E 2 1 6873060E 4 5 9105 20 3 4009635064 6 86040564E 1 3 9980065E 2 1 0586 1527E 2 2 30087 106 4 5 2513 50 3 6403150558 6 94 70477E 1 3 92 792 75E 2 1 12352489E 2 35 6150 700E 5 5 84350 100 353 80 78260422 7 00 12963E 1 3 9119314E 2 1 128 5336E 2 1 3241 100E 5 5 835 Paste Table Figure 2 70 Paste BOM Dialog Box with Coefficients Displayed The latter will give the same peak rainfall values as the rational method because they are derived directly from the I F D data They can be added to the rainfall pattern data base by pressing the Add Synthetic Storm button in the Rainfall Data property sheet a
184. ata is entered the allocated names appear in the Main Window DRAINS will not run until all the required data is entered Even if the data for all components are entered question marks will remain if the connections between components are incomplete Table 1 1 defines the data for the pits in this system If you are following this example enter the appropriate values for the five pits The names of pits can be up to 10 characters long and those of other components may be slightly larger Assume all pits to be NSW RTA Roads and Traffic Authority now Roads and Maritime Services SA2 pits at the slopes shown in the table Table 1 1 Pit and Outlet Node Data for the Orange Example Longit Ponding Ponding Pressure Surface Blocking Pit Type udinal Change pa Factor Slope Coeff Ku O clear rit ea sf as es oo ea so Mia a o os a o E tps Ca OnGrace 3 4s 22a 00 TPs onses 1 o 217 00 outers Nowe i a ome Nove i iY SS ts outers Nove o o a Pit 2 is a sag pit located in a hollow in which stormwater can form a pond over the pit For this type of pit there is an additional page on the property sheet labelled Pond Properties where extra information has to be provided an allowable ponding depth and a maximum ponded volume here taken to be 0 15 m and 2 m Drainage Pit Pit Properties Pond Properties QUDM Pond Geometry a Simple geometry half Max ponded de
185. ation of pit Surface Hev ml pressure coefficients Pit Family ald DMR Gully Fit both 0 25 2 grade Pit Size 5 Lintel Pressure loss coefficient 5 Ku for full pipe flow Pitt has bolt down impermeable lid This pit is Blocking Factor Oto 1 0 0 unblocked New can be designed f Use default value of 0 5 C Existing cannot be designed C You specify Notes Figure 2 6 Drainage Pit Property Sheet for a Sag Pit Upper Part DRAINS will make the ponding area overflow if the water depth exceeds the maximum ponded depth specified in the pit property sheet Where two sag pits are connected by an overflow route the overflow level of the upper one its surface level ponding depth should be higher than the overflow level of the lower pit as shown in Figure 2 7 Otherwise in basic and standard hydraulic model calculations DRAINS will have overflows going uphill and will display a warning message either prior to running a model or in the report at the end of a run Overflow Level Between On Grade Between Sags and Sag Pits Ca eee Pit A 5 Sag Pit l AJG Sag Pit A T Figure 2 7 Relative Overflow Levels The overflow level of a sag pit is below the surface level of an on grade pit that overflows to the sag pit otherwise messages regarding uphill overflows will appear In reality on grade pits may be submerged by ponding over a nearby sag pit as is the case in Figure 2 7 d Baseflows and Direct
186. ational method results to tables employed by Queensland councils These outputs present pit pressure change coefficients k values developed by a procedure that looks up the tables presented in the Queensland Urban Drainage Manual Details are provided in the DRAINS User Manual and Help system DRAINS User Manual A 24 November 2014 Overflow Route OF A2 i Basic Data Cross Section Data Shape Half road section 7 m wide Safe Depth for Major Storms m 0 3 Sate Depth tor Minor Storms im 0 15 You specify Sate Depth x Velocity sq m sec 0 4 of downstream For Major Storms catchment flow cared 15 Safe flow 1 000 cu m sec by this channel Maximum flow 0 208 cums 3 Comesponding velocity 1 51 m s Maximum depth 0 126 m Calc Slope Maximum flow width 2 90m Madmum Dx V 0 19 sq m sec Channel slope Figure A 24 Display of Overflow Route Flow Characteristics Critical Depth E gt LLI Distance m from U S end Figure A 25 Overflow Route Long Section from Premium Hydraulics Model DRAINS User Manual A 25 November 2014 wl F r Fil real 4 oa pri en Miad beet E ifs hisk lier er x nwa breve Pigi Leo Urarred TT irs za L d i e T B MOTE per e i F a H r EGAN CALCLE ATHIK EAA HEE T a a a 7 a s 1 a a a a m b En p Eabh we eet We Sete eai bah Torni m Cee Pe Tei the whee wi WD Pipetli Pepe Pepe Pero FANE HDH Waira Tery Se jik Lee
187. aulic model calculations The Toowoomba Estate Example with Results drn file on the CD defines a system containing both pipes and open channels shown in Figure A 32 HGL and water surface levels at nodes and plots of longitudinal and cross sections can be inspected If it is required to find a surface water level at a location along a channel perhaps at the site of a proposed development then a node should be located at this point DRAINS will than specify calculated flow levels at this exact point A 6 Analyses One of the main uses of DRAINS is the analysis of localised flood problems It is difficult to define precise rules for this as there are many variations in development projects and drainage systems particularly in established urban areas The level of detail required and the handling of upstream and downstream drainage systems require judgement balancing the accuracy required against the resources available such as funding information and time The use of sensitivity analyses repeating calculations with different possible inputs is probably the most powerful tool for examining and reducing uncertainties For example if tailwater conditions are uncertain DRAINS runs can be made with different tailwater levels and the results assessed to come up with a reasonable but conservative estimate DRAINS User Manual A 29 November 2014 3 Toowoomba Estate drn DRAINS 3 Crk 8 38 m from Upstream Node o Fi
188. be able to run this model with the Viewer but you can open another Gymea model named Gymea Piped Drainage Model with Results drn from the demonstration examples This displays the run results shown in Figure A 3 More detailed explanations are provided in the main body of this DRAINS User Manual and in the Help system A 3 Information Required for Checking A 3 1 General This section spells out in checklists the basic information required to assess DRAINS models for various purposes The pertinent information is e The physical nature of the system shown in design plans or system diagrams e The assumptions made in the design or analysis these should be reasonable and conform to council requirements or else be supported by references to manuals or other documents when they differ from council guidelines e The extent to which the design meets stated design requirements systems should convey or store runoff so that flooding of properties and hazards to persons are avoided at appropriate levels specified by average recurrence intervals ARIs Where a submission accompanies a development application to a municipal council the design needs to comply with council guidelines that are specified in a number of forms codes manuals development control plans and are usually available on council or drainage authority websites It may be reasonable to submit a design that does not meet some requirements provided that is accompanied by ev
189. be within certain ranges of expected values in others it queries values that appear to be unusual Warnings like those shown in Figure 3 29 also appear when a run is initiated and after a run Itis important to heed these and to try to eliminate the causes ERROR You cannot hawe both an owerflow route and a link from a F simple node See NGOS E Run Log for EXILE BAY Existing DRN run at 14 38 17 on 12 1 2011 ater was lost from the system at 240010 ls thie corect If this water re enters the system further downstream you should draw an overflow route from this location Upwelling occured at 010260 010230 040010 050010 010200 010170 300010 190030 OFO020 010040 170010 Freeboard was inadequate at more than 20 pits The masinun flow exceeded the safe value in the following overflow routes 0190020 oD 0010 0010040 oO 10050 2010080 oT 0090 of10700 Figure 3 29 Warning Messages see also Figure 3 28 lf a serious computational problem occurs and DRAINS cannot resolve this an error message may appear and the program will shut down after this is closed Sometimes such messages will request that you contact Watercom Pty Ltd to resolve the problem 3 4 4 Options for Modifying Pit Pressure Change Factors The Revise Pit Loss Coefficients option alters the pit pressure change coefficients using an algorithm based on an approximate relationship developed by Mills or a method based on the Queensland Urban Drainage Manua
190. binations demonstrate how this model produces different peak flows depending on the assumptions and rainfall inputs applied The last of the three variations provides peak flowrates that are the same as the rational method estimates Table A 10 also displays the volumes of hydrographs generated for selected storm patterns These are expressed as a percentage of the total rainfall in these patterns The ILSAX models show a spread of volumes depending on AMCs and storm durations while the ERM results show consistent volumes of 65 for 5 year ARI and 78 for 100 year ARI These percentages are the weighted average C values obtained from the impervious and pervious coefficients The ERM assumes that the volumetric coefficient ratio of total runoff to total rainfall is the same as the runoff coefficient used to define peak flowrates A designer at Gymea using a Soil Type AMC combination of 3 3 or 8 4 would generally generate greater volumes than from the ERM If the results were applied to a detention basin design a larger storage would be required when the ILSAX mode is used Similar variations in ILSAX model results to those caused by AMC occur when Soil Types are changed although the extent of variations is not as great To check whether these results apply in other parts of Australia the analysis has been applied using rainfall and parameter values applying at a location with higher rainfalls the suburb of Manly in Brisbane and a site w
191. ble scope to alter the system The available information will be e a survey of the area showing contours to a standard datum such as AHD and a mapping grid such as MGAQ4 available on paper and electronically as a CAD file in a format such as DXF or DWG e the planned layout for roads either on plans or as a partly or fully completed road design model DRAINS User Manual 4 11 November 2014 e cadastral property boundary data available on plans and as drawing layers over which the contour drawing can be overlaid e the technical requirements of the consent authority for the project e ocal design rainfall data and other local information There is usually some give and take in design so that the road and allotment layout can be altered to suit drainage requirements However the initial layout made by an experienced subdivision and road designer should anticipate potential conflicts The products or deliverables of the design will be a drainage layer in the drawings with all drains and channels detailed together with design calculations Plans specifications tables of quantities and estimated costs can be derived from these The main aims in designing pipe networks with DRAINS are to develop a file that describes the proposed system and to produce the deliverables plans and documentation The single drn file can be run for both Design and checking by Analysis and can quickly be re run with data and results being transfe
192. casts from the Webcast Archive Note You need Adobe Flash Player to view these videos or contact Andrew English on 03 9568 0077 or andrew english ccivilsurveysolutions com au 3 2 10 Transferring from MXROADS The Bentley MX ROAD software has a connection to DRAINS that operates in the same way as the Advanced Road Design procedure described in the previous section The commands File Import gt Import Advanced Road Design file File Export gt Advanced Road Design file can be used to import and export MXROADS files For detailed information contact support at Bentley Like the other connections this does not work when DRAINS has a rational method hydrological model It operates when the DRAINS model has an ILSAX or ERM model specified 3 2 11 Transferring from CatchmentSIM CatchmentSIM developed by Chris Ryan 2005 is a program that manipulates topographic data to define catchments and to determine catchment characteristics Starting with data in a 3 dimensional vector format such as MID MIF or TIN files CatchmentSIM converts these to a raster grid from which catchments and sub catchments can be defined For urban catchments barriers to flow along fences and road crowns can be specified and the sub catchments derived reflect these This information can be used to develop DRAINS models For further information contact Catchment Simulation Solutions at www csse com au 3 2 12 Setting Up New Pipe Pit and O
193. connect the storages Both storages and overflow routes can be small or extensive A typical situation is shown in Figure 2 28 The overflow route will connect the ponded water on each side of the street It will begin at the road crown and end at the downstream pit Gutter Crown Overflow Route Flow Cross Section Figure 2 28 Flow Through a Road Low Point During premium hydraulic model calculations DRAINS will monitor the ponded levels in sag pits at each time interval When the defined ponding level assumed to be the level at which a spill will start to occur is exceeded overflow rates and ponding levels will be determined using the weir control specified in the overflow route property sheet Figure 2 27 DRAINS will also calculate depths of flow in the overflow route and allow for a tailwater level due to ponding downstream if the overflow route terminates in a sag pit or detention basin If the water level in the overflow route is greater than the weir crest level the weir discharge will be reduced using a submerged weir equation as described in Section 5 6 4 It is important to establish pipe and overflow route levels and other details correctly DRAINS provides a large number of checks to detect errors but final responsibility for the accuracy of the model remains with the user d Kinematic Wave Routing Inputs Overflow routes can also be used to model stream linkages in a R
194. cted as an on grade pit on a slope so that no pond will form over the pit Note how pit types and sizes are selected from a data base of pit types using two drop down list boxes When entering data you can move from box to box using the Tab key on your PC s keyboard DRAINS User Manual 1 13 November 2014 3 Untitled DRAINS ec File Edit Project View Draw Run Help oele S ofejal m olv o aly Edit Data Copy Shape View HGL Graphs View HGL Tables Delete 4 Press F1 for help Figure 1 20 Pop Up Right Mouse Button Menu Drainage Pit Pit Properties QUDM Pit Family NSW RTA SA Inlet 3 crosstall 3 grade Pit Size SA1 Type 2 3 longitudinal grade r Pressure loss coefficient 45 Ku for full pipe flow Pit has bolt down impermeable lid This pit is Blocking Factor Oto 1 0 0 unblocked New can be designed Use default value of 0 Bisting cannot be designed You specify Figure 1 21 A Drainage Pit Property Sheet The pit pressure change coefficient value of 4 5 is suitable for a pit at the top of a drainage line You can obtain further information about these factors which influence the water levels in the pipe system from the Help system or from Section 0 DRAINS User Manual 1 14 November 2014 After closing the Drainage Pit property sheet you will find that the pit name has changed and the question marks have disappeared As d
195. d MapInfo produced by MapInfo Corporation www mapinfo com but Autodesk Map www autodesk com and Intergraph www intergraph com There are also a number of companies that provide systems based on the main types of software GIS file structures can be complex In Maplnfo two file types with suffixes MID and MIF are required so that 12 files are generated in a transfer from DRAINS B Holroyd OSD dxf WordPad Ciel ak al qeg a 100 AcbhayrbolTable 7O 14 330 5 100 AcbhayrbolTableRecord 100 AcDbLinetypeTableRecord 2 ByBlock 7O O 3 Ta 65 73 O Figure 5 34 ASCII File in an Editor b ESRI ArcView Formats ArcView stores spatial information in various formats The data imported or exported by DRAINS are in a set of three binary files all having the same initial part of their name a SHP file the main file defining a number of records for shapes points lines poly lines or polygons defined by the coordinates of their vertices e a SHX file acting as an index to the records in the main file e a DBF file containing a DBASE table of attributes associated with each record To specify an object such as a pipe fully a set of these three files is established The transfers to and from DRAINS involve files for up to six objects pits sub catchments pipes overflow routes survey data on ground levels along pipe routes and positions of other services a total of 18 files plus a DXF file containing t
196. d Storage N Storage Figure 4 13 Ponding Storages on Streets and in Allotments Storages on streets might be modelled as detention basins with a height storage relationship and a low level outlet to the pipe system Their high level outlet or outlets can be modelled as one or more weirs usually located a driveways into properties Storages within allotments can be very complicated with flows being blocked by gates and fences so that several instances of ponding may occur on the one property Some situations can be modelled readily such as flow under a fence represented as a sluice gate or flow over a low wall as a weir flow However in many Australian situations the barrier may be a metal Colorbond fence extending to the ground Such fences can probably hold back stormwater to a depth of 1 m or more When failure occurs there may be catastrophic effects from the resulting rush of water and debris Modelling such events is difficult Our knowledge of how they are initiated is poor and DRAINS does not model dambreaks of this type Existing systems that have been augmented can have two pipes with different characteristics running more or less parallel These might be modelled as multi channels if there are no significant inflows along one of these that will change the distribution of flows If this is the case they can still be modelled as two DRAINS User Manual 4 16 November 2014 outlet pipes from a pit DRAINS can model these us
197. der roas 300 o6 Existing Y ie romme poent an sess 475 0s conerie unaerroaas soo 0 fessin Pipe A 3 0 005 Concrete under roads 0 6 Existing 4 32 Record 14 lt 1 i Show Al Selected Records 0 out of 23 Selected Options DICE Ieee wv Figure 3 8 ArcView Tables of Characteristics of Nodes and Pipes ready for Import into DRAINS DRAINS _ 2 You are about to import data from a set of 6 ESRI shapefiles These include data for nodes including pits etc pipes pipe survey data Each shapefile comprises a set of 3 files with the extensions SHP SHX and DBF so that a total of 18 files are needed You can select any one of these to open and DRAINS will read all 18 If there is a dxf file of the same name a background layer will be imported from this file The next step is to specify the file name Continue Figure 3 9 Shapefile Transfer Message DRAINS User Manual 3 6 November 2014 ex Fe Date modified Type 26 05 2003 7 52 AM DWG True 23 05 2003 7 20 AM DWG True File name Oldtown_Nodes shp j Open Files of type ESRI Shapefiles shp Cancel Figure 3 10 Choosing a Shapefile 3 Untitled DRAINS as File Edit Project View Draw Run Help Os S oleala B olv o le Pipe from Pit C 2 to Pit C 3 EES Pipe 4 9 Pipename EEE Pipe length m 47 3 Upstream invert elev m
198. e Peak water level Freeboard Surface level Ku for pats a J 303 w Nothing Notes 1 Peak flows and water levels willbe forthe stonm curently selected in the Storm List wandow el inthe basic model peak flow is measured atthe upstream end of the link In the unsteady model it rs measured atthe cente ofthe link 3 Mex width of flow could be atthe upstream end centre or downstream end of an overflow route Figure 3 19 Dialog Box for Customising or Changing the Text Displayed 3 Toowoomba Estate DRAINS File Edit Project View Draw Run Help oem S ole lml a oxe of ale 705 90m 707 2 0 75 ul 7 OF B 3 707 1 706 09m 77 L B 705 28m 2 OFEA omen OF B 2 TEDA Catt Cat a CatB 4 P706 1 F 704 06m 703 54m 1 705 3 forxa OF B 1b j i 704 93m OF B4 70413m 3 w Y Chn 1 704 4 355m OFB 6 Sai S e ir sA e a 280m AFCA 4 f S OEE a E SEO E ae oUm gaan 706 2 4 y e OFB 5 705 3 70230m 7 703 52m a OF CA 70302m 72 88 TACA 72 38m 7 Y 704 3 OF B 7 4 P 7 Mth n r Press F1 for help Figure 3 20 Drainage System with Surface Levels coloured purple replacing Pit Names and Upstream and Downstream Invert Levels replacing Pipe Names The wheel on a mouse can also be used to zoom in and out of DRAINS models To pan you can press the Pan button on the Toolbar E or the sliding bars on the margins In large drainage systems you can
199. e Separate Total Method ARR87 areas areas Storms Synthetic Synthetic 5 Year ARI Flowrates m s 100 Year ARI Flowrates m s 5 Year ARI Runoff Volumes from the Whole Catchment of Rainfall Designstom TTT Sminte 36 s 52 o m sme se s ee s oo asmu 46 59 72 8 smee T C T o el 100 Year ARI Runoff Volumes from the Whole Catchment of Rainfall sme 4 a 70 a ne 78 J sme 66 o 2 o en T asnu 68 76 s e 7e smee 0 O O T T ela The ERM dies not run with the total area assumption and ARR87 storms DRAINS User Manual A 15 November 2014 Relative results vary with the proportions of impervious and pervious areas but the rational method and ERM generally specify lower flowrates than the ILSAX models specially where an AMC or 3 or 4 is used which will be the usual situation at Gymea The reasons for the rational method providing lower flowrates than ILSAX are e ILSAX uses ARR8 7 patterns such as that shown in Figure A 5 which contain higher peak intensities than the rational method which assumes that rainfall occurs as a rectangular block e The ILSAX hydrological model gives different runoff volumes to the rational method and applies different routing procedures It only applies a depression storage loss of 1 mm for impervious areas while the rational method and ERM apply Cs 0 86 and C400 1 0 The three alternative ERM com
200. e so that flows or HGL levels at particular locations can be checked on screen 19 files three ESRI SHP SHX and DBF files for nodes pipes sub catchments overflow routes survey points along pipes and conflicting services plus an optional DXF file of the DRAINS background DRAINS drn File 13 files two MapInfo MID and MIF files for nodes pipes sub catchments overflow routes survey points along pipes and conflicting services plus an optional DXF file of the DRAINS background Figure 4 14 Transfers of Data Between DRAINS and GIS Programs DRAINS does not export overflow routes as polylines but as lines connecting the first and last points of the overflow route polyline To display complex routes such as those passing through properties it is recommended that these be represented by two or more segments joined at nodes Ultimately drainage system managers can develop systems where revised DRAINS models can be created from information on previous DRAINS models in their GIS As new developments and re developments occur it will be possible to include these Results from various models can be retained in the GIS system The combination of DRAINS with GIS allows managers to maintain and ongoing record of their drainage systems that included records of performance and flooding risk 4 3 6 Performing Flood Studies with Storage Routing Models The catchment must be defined on a contour map and sub catchments defined u
201. e 2 12 requires as a minimum that you enter a name length and number of parallel pipes default value 1 and specify a pipe type from the drop down list box DRAINS User Manual 2 9 November 2014 Pipe from Pit A 3 to Outlet Pipe name PipeA3 Pipe length m Upstream invert elev m 29 155 Fipe Type Concrete umder toads Downstream invert elev m 28 69 Slope Nom Diameter mm I D mm 675 BFS Exit logs coefficient K This only appears for the No of identical parallel pipes outlet of a Include Non Retur Valve detention basin or the last pipe Fipe Roughness During Design runs this pipe in a network f is new diameter and level can change f is new but diameter and level are fixed f ou specify C is existing diameter and level are fixed Cis new downstream invert level is fixed This only appears for the last pipe ina Ok network Cancel QUANTITIES Survey Data Excavation volume 62 7 cum Rock volume M A Scale off Length Length of trench deeper than 1 2m 37 7 m at an average depth of 1 58 m Help Figure 2 12 Pipe Property Sheet This information is sufficient for a Design run in which DRAINS will specify the pipe diameter and invert levels The pipe type chosen must be defined beforehand in the Pipe Data Base located under the Project menu options Pipe lengths can be scaled from coordinates if the system is drawn to scale Rectangular pipes can be used though not f
202. e backwater curves in pipes and channels Where pipe flow is supercritical the water surface is assumed to follow the normal depth In open channels the basic model conservatively assumes surfaces to be no lower than the critical depth The basic calculations define HGLs at nodes and inside pipes for subcritical part full flows but they only presents the results at nodes They define flowrates in links such as pipes or channels and provides continuity checks in the spreadsheet output summing the inflows and outflows at each node The flowrates presented for pipes are those calculated at their upper ends so that the flows displayed in DRAINS outputs at a particular time will probably differ from the flowrates emerging from the pipe at that time If a pipe is unpressurised these outflows will be the same as the flows that entered a conduit a certain number of time steps previously depending on the pipe length and flow velocity If it is pressurised there is no time delay DRAINS manages the transfers between part full and full pipe flow so that there are only small continuity errors c Unsteady Hydraulic Calculations The unsteady flow calculations carried out with the standard and premium hydraulic models are quite different using the equations of mass and momentum conservation Section 5 6 4 to set up a matrix specifying the equations to be solved over a space time grid The space or x dimension represents the conditions at various points
203. e change coefficients March 2009 Release of the free DRAINS Viewer December 2010 Replacement of the basic hydraulic model by the standard and premium models Parallel processing introduced to greatly reduce run times 2012 Multiple rainfall pattern entry New orifice and weir components 2012 14 Enhancements to unsteady flow calculations improving speed and stability 2014 Enhanced pipe system design procedure The rational method the extended rational method and storage routing models have been added to the original ILSAX hydrological model The basic hydraulic model which underwent considerable development between 1989 and 2010 has now been replaced by unsteady flow models 5 3 Hydrology 5 3 1 General Simulation models such DRAINS require a model to transform rainfall patterns to runoff hydrographs in the part of the hydrological cycle shown in Figure 5 2 Urban stormwater drainage design can be carried out by three categories of models a simple models that produce a peak flow estimate only such as the rational method b hydrograph producing models such as the time area model in ILSAX applied to storm events and DRAINS User Manual 5 2 November 2014 c more complex models capable of continuous simulation of hydrographs such as the Stormwater Management Model SWMM Precipitation Evapo transpiration T Rainfall oe Natta RRE SNOWPACK Soe STORAGE SES Snowmelit SEAR Se ogee ae In
204. e equation 5 41 Orifice flow 5 21 OSD 2 38 Other services 2 11 Outlet control for culverts 5 39 Outlet node property sheet 2 9 Overbank flow areas 2 28 Overflow path critical location 2 21 Overflow path cross section 2 20 Overflow route 2 17 Overflow route data base 2 53 Overflow route property sheet 2 17 2 18 2 19 Overflow routes 4 10 Overland flow 5 7 Part full flow change 4 6 Paste data from spreadsheet 3 30 Paved area 1 15 5 3 Performing calculations 4 2 Pervious area runoff coefficient 5 17 Pine Rivers chart format 3 30 Pipe friction equations 5 32 Pipe data base 2 48 Pipe Data property sheet 1 17 Pipe property sheet 2 9 2 10 A 21 Pipe system hydraulics 5 30 Pipes 2 9 rectangular 2 10 survey data 2 10 Pit blocking factor 5 25 inlet capacity 5 21 on grade 2 4 pressure change 5 33 pressure change coefficient 2 4 sag 2 4 Pit blocking factors 2 5 Pit data base 2 50 Pit or sump outlet 2 23 Pits 2 4 Pits in swales 5 29 Ponding 4 15 Pop up menus 3 16 Print DRAINS diagram 3 23 Prismatic open channel 2 28 property sheet 2 28 Programming of DRAINS 4 1 Project menu 1 6 2 2 Property balloons 1 18 3 16 Property drainage requirements A 3 Pump link 2 28 Pump property sheet 2 28 Quantities 3 18 3 21 QUDM design chart format 3 30 QUDM pressure change coefficient method 5 39 QUDM revision of Ku coefficients 3 19 Queensland pits 5 25 Queensland Urban Drainage Manual 3 1
205. e on other factors however investigations conducted in the U K with the TRRL Method concluded that this degree of accuracy was not necessary c Catchment Surface Types The sub catchments draining to each entry point on the pipe and channel system can be obtained from maps aerial photographs and GIS information as well as field inspections The likely effects of fences along property boundaries and other barriers must be assessed In the ILSAX model used in DRAINS each sub catchment must be divided into the sub areas shown in Figure 5 6 with the following surface and drainage characteristics e paved areas impervious areas directly connected to the pipe system including road surfaces driveways roofs connected to street gutters etc e supplementary areas impervious areas not directly connected to the pipe system but draining onto pervious surfaces which connect to this system These may include tennis courts surrounded by lawns house roofs draining onto pervious ground etc distributed evenly next to the grassed area and e grassed areas pervious areas directly connected to the pipe system including bare ground and porous pavements as well as lawns 4 L supplementary Area n Grassed Area Pipe system Paved Area Figure 5 6 ILSAX Model Surface Types In DRAINS the total sub catchment area and the percentages of paved supplementary and grassed areas must be specified for each sub catchment If there i
206. e pit and overflow route data base information You can use it as template for new jobs in the same area A DB 1 file contains only the pipe pit and overflow route data base information Itis in the same format as the files distributed with Drains for NSW QLD etc Cancel Figure 3 62 Dialog Box for Exporting Template Files 3 6 Help Options The Help system in DRAINS can be called in three ways a by choosing Contents in the Help menu b by pressing the F1 key or c by pressing a Help button in a property sheet or dialog box to deliver context sensitive Help DRAINS User Manual 3 37 November 2014 It is implemented as a HTML Help system in a three pane window with an index as well as topics as shown in Figure 3 63 The panes can be re sized as required 9 DRAINS Help aig a E _ Print Options X Introduction Type in the keyword to find Welcome to DRAINS a program for designing urban stormwater drainage systems and analysing their flooding behaviour This Help System applied both to DRAINS and to the DRAINS Viewer For information on how to install and apply the Viewer please go here As well as modelling piped drainage systems DRAINS describes detention basins open channels rural and urban catchments Users can apply four different kinds of hydrological model and have a choice of standard and unsteady flow hydraulic models Antecedent moisture condition More information is given in the following
207. e transferred to a spreadsheet Basic Data Cross Section Data Alow Routing in Basic and Standard Models Simple Translation no attenuation Kinematic Wave Name Reach C Overflow Route Reach Reach Length m 250 Scale off Lendl Basic Data Cross Section Data Extra Data for Premium Hydraulic Model Shape Creek Section tt ti t s SY Upstream IL m Downstream IL m 2 13 a i 1 as Safe Depth for Major Storms m 0 3 Safe Depth for Minor Storms m 0 3 Safe Depth x Velocity gg m sec 0 5 of downstream catchment flow camed 0 by this channel Channel slope 1 3 Cale Slope Figure 1 50 RAFTS Stream Routing Reach Property Sheet 3 Shepparton RAFTS Rural drn DRAINS lo x File Edit Project View Draw Run Help Disa 8 elak oule e ale Worst case major storm 3 Cat A Hydrograph A File Edit Properties Flow rate cu m s 80 100 120 140 160 180 200 220 240 260 Time mins gi a el A a Results of Standard Hydraulic Analysis Figure 1 51 Results of Storage Routing Run DRAINS User Manual 1 30 November 2014 X4 2 MENUS TOOLS AND DATA BASES 2 1 Introduction This chapter presents the options and tools that are used to create and tailor DRAINS models Drainage systems can be created with the tools on the Toolbar or can be partially imported using menu options With optional modules covering rational method storage r
208. ear 25 minutes storm average 78 mm h E A Pipe E Hydrograph e a iTS 20 40 60 80 100 120 0 20 40 60 80 100 120 Time mins Time mins Pipe C 1 Maximum Flow and HGLs for the Selected Storm 4 AR amp R 5 year 25 minutes storm average 78 mm h Zone 1 0 60m Cover 30 800 Pipe Long Section 30 077 an OO i Pit C 1 29 777 Length 8 metres Diameter 300 mm PitA3 Pipe Slope 1 25 Omax 0 067 cu m s Ymax 1 50 to 1 90 m s 4 Results of Standard Hydraulic Analysis Figure A 3 Results from a Design Run and Standard Hydraulic Analysis of the Gymea Example To understand this more completely you can view one of the demonstration examples that are installed with DRAINS in C Program Files Drains StandardExamples This file named Gymea ILSAX Example Standard drn can be opened using the Open option in the DRAINS File menu Note that if a blank screen appears when a model is loaded the model can be located using the Index Sheet option in the View menu The Gymea system located in suburban Sydney includes a background showing street and property boundaries imported from a CAD file Components can be inspected by opening the property sheets for the components as shown in Figure A 2 If Property Balloons is switched on in the View menu properties of components can also be seen in balloons that appear as the mouse pointer runs over them DRAINS User Manual A 2 November 2014
209. ed and exported to a spreadsheet via the Windows Clipboard 3 Gymea ILSAX Example Standard DRAINS 2s File Edit Project View Draw Run Help Dem S oleam 0 w wus JAR amp R 100 year 25 minutes storm average 133 mm v 30 6 A 30 5 E 30 4 2 230 oe 30 3 Soy ORRON enema PIR RAST EMER Outlet Obvert Level 0 184 30 2 Qo 66 Sl www Ee fe ae EE e Pit B 1 HGL AR amp R 100 year 25 minutes storm average 133 mm h Zone 1 Lo xs File Edit Properties HGL m 20 40 60 80 100 120 Time mins A Pipe B 1 Hydrograph AR amp R 100 year 25 minutes storm average 133 mm h Zone 1 e x pe ograp ye g File Edit Properties 0 24 Flow rate cu m s 0 20 40 60 80 100 120 Time mins Results of Standard Hydraulic Analysis Figure A 23 Display of Hydrographs and Hydraulic Grade Lines HGLs The most critical output will probably be the flow characteristics in overflow routes which can be displayed by opening the property sheet for an overflow route and going to the second page tagged Cross Section Data As shown in Figure A 12 a picture of the section is shown together with flow widths depths velocities and velocity depth products This can be used to check the critical characteristics for street drainage systems detailed in Section 3 5 the allowable width and velocity depth product It can
210. el upstream of the bridge A multi channel cannot be placed downstream of a bridge a short section of single channel can be interposed however 8 You cannot have an open channel coming out of a pit However a short section of pipe and a simple node might be used to link the pit and a channel DRAINS User Manual 2 37 November 2014 In a DRAINS Main Window it is possible to have several separate drainage systems These may be completely independent or may be connected by overflow links When DRAINS runs it applies the same rainfall and loss data to all systems unless local options are selected in the Hydrological Model and Customise Storms options in the Sub Catchment property sheet described in Section 2 3 5 This feature allows systems to be analysed together to provide before and after comparisons The example file Sydney OSD drn provides such a comparison for an on site stormwater detention system As shown in Figure 2 58 the pre developed catchment is set out on the lower left and the developed drainage system around a house and backyard occupies most of the window These two systems are run together using the same project specifications allowing a direct comparison of results 3 Sydney OSD Standard DRAINS 3 File Edit Project View Draw Run Help Close Djesa S lalale olveaa Pre development model Pre Dev Cat Outlet e Outlet 2 a Total Outflow 1 Stoo Out ipe Post development
211. ely simple bridge layouts Use of HEC RAS is recommended for complex arrangements involving multiple openings and broad channel cross sections DRAINS uses the AUSTROADS procedures to define the afflux or rise in upstream water level caused by a bridge constriction It does this at each calculation time step for the current flowrate and downstream water level As with culverts allowance is made for possible overtopping and submergence of the bridge deck treating this as a weir Any overflows are added to the flows through the bridge opening occurring at the same time 5 10 File Formats 5 10 1 General This section provides some notes on file formats as a guide to persons exchanging data between DRAINS and other programs 5 10 2 Drawing File Formats DRAINS can import and export graphical data in DXF format As shown in Figure 5 34 this is an ASCII format which can be edited on a text editor DRAINS User Manual 5 43 November 2014 5 10 3 GIS File Formats a GIS Systems Geographic Information System GIS programs combine a mapping facility with a data base of information on the spatial position of components such as drainage pits and pipes and on their other attributes such as pipe diameters Objects displayed in different ways according to one or more of their attributes Maps can be produced on paper or can be inspected electronically The most common products used in Australia are ArcView produced by ESRI www esri com an
212. en DrainsViewer The Main Window will then open and after you have closed the introductory message will appear as shown in Figure A 1 If needed Help can be called from the Help menu or by pressing the F1 button Options in the View menu can be used to alter the look of the model 3 Untitled DRAINS Viewer J Menus Soe x File Edit Project View Draw Run Help Dist S lalaa als Toolbar Space for displaying drainage system components Current Operation Press F1 for help Figure A 1 Main Window of the DRAINS Viewer If you are familiar with DRAINS you will find that the Viewer operates in the same way except that the model cannot be altered or run Initially the Viewer will display a blank space As in DRAINS the operations of the Viewer are controlled from menus Drainage systems are constructed from a set of named components pits sub catchments pipes overflow routes channels etc that are joined together as shown in Figure A 2 The information for each component is set out in a property sheet that can be opened by right clicking on the component and selecting Edit Data from the pop up menu DRAINS User Manual A 1 November 2014 3 Gymea ILSAX Example Standard DRAINS Viewer X File Edit Project View Draw Run Help Djen S lalale slie eoo e ala Drainage Pit Pit Properties QUDM Property ben Baseflow Edit Data Sheet for sag pit 5 on grade pit
213. entry capacity relationship applies and bypass flows and overflows from the pipe system can occur With the elaborate hydraulic routing calculations that are applied in DRAINS it is not possible to explain these processes in detail but generally various inflow hydrographs are added at each time step and combined with calculated flows through the upstream pipe system 5 3 3 Testing and Verification of DRAINS Testing during development has shown that the ILSAX hydrological model has been reproduced exactly in DRAINS with the additional feature of more detailed calculations of supplementary area flows operating satisfactorily In comparisons with data from gauged urban catchments ILSAX has been shown to provide results that are at least as good as other urban hydrology programs such as SWMM see Vale Attwater and O Loughlin 1986 O Loughlin et al 1991 and Diamante 1997 2000 Table 5 7 and Table 5 8 show comparative results between recorded data SWMM ILLUDAS SA a predecessor of ILSAX and ILSAX showing that the ILSAX Hydrological Model provides a reasonable reproduction of storm flow characteristics Table 5 7 ILLUDAS SA and Observed Results Mein and O Loughlin 1985 Catchment Storm Date Total Peak Flowrate m s Name a ILLUDAS ILLUDAS Vine Street 6 11 71 sa 054 069 Sunshine 5 2 73 sf 8 se DRAINS User Manual 5 14 November 2014 N Melbourne 31 10 75 28 14 14 053 060 7 878 43 09 14 033
214. epression storages and AMC e the proportions of paved supplementary and grassed areas e the times of entry for paved supplementary and grassed areas All of these relate to physical quantities that are easily understandable so that values that are estimated as is usually the case will not be greatly wide of the mark Where rainfall and runoff data for storms is available the hydrological modelling in DRAINS can be improved by calibration though not to a large extent O Loughlin Haig Attwater and Clare 1991 Times of entry and travel through a drainage system can be defined more accurately Less accurate calibrations can also be carried out based on ponded volumes If rainfall is available for a storm DRAINS can estimate the stored volume at a location where depths have been observed The volume from DRAINS can be compared with that corresponding to the maximum depth observed Calibration of drainage system hydraulics is usually performed by altering the roughnesses of conduits to match observed water levels Observations may often be available for open channels but are unlikely to be available for closed pipe systems unless a special gauging programme is undertaken If such information is available it can be used to verify the DRAINS model though it is likely to be difficult to refine the model because of the many pipe links that may be involved 4 2 9 Interpretation of Results Most DRAINS hydrographs and HGL plots are simple
215. er Manual A 4 November 2014 Table A 2 Typical Requirements for Assessing Inter Allotment Drainage Systems Plan view of piped drainage system showing Optionally the sub catchments leading to locations of pipes and pits and extents of flow each pit should be displayed with their areas paths and possibly land uses Cross section of flow path and sections of any special features such as flow e fencing Optional Items Items Pipe long sections Long sections exported from ar can be presented Drainage calculations These can be the relatively simple calculations employed with property drains DRAINS provides these Table of quantities Table from DRAINS may be presented Pipe design ARIs are usually in the range 5 to 20 years with overflow paths needing to be assessed for 100 year ARI flows A 3 4 Street Drainage Systems Piped drainage systems are required for subdivisions and occasionally for property developments that need to connect to council drainage systems along streets They may also be required for infrastructure developments such as motorways airports and port works The usual documentation required for checking is described in Table A 3 Much of this will be included in subdivision plans along with drawings of roadworks and other infrastructure Table A 3 Typical Requirements for Assessing Street Drainage Systems Plan view of piped stormwater drainage On this or a separate plan the sub system showing locations
216. ercom Pty Lid inlet capacity relationships are available for many Australian pit types as indicated in Table 5 13 to Table 5 19 DRAINS User Manual 2 50 November 2014 These may be periodically updated To update a DRAINS model it will be necessary to import the data in the revised db1 file using the Import gt DRAINS Database DB1 File option in the File menu and then change the name of the old relationship to show that it is obsolete The pit types nominated for particular pits can then be changed one by one or altered by exporting the system data to a spreadsheet as described in Section 3 5 4 altering pit type and size names in the columns and then exporting the altered spreadsheet back to the DRAINS model Pit Properties General On Grade Data Sag Data SA2 Type 5 1 longitudinal grade Comments This has a kerb inlet 1 83 m long See further comments for SA1 Pit Pit Properties General On Grade Data Sag Data Inlet Capacity Gin vs Approach How Qa Qin 3 Faste Data b 0 Copy Data yar 107 HEC2 2 Wizard 0 035 Pit Properties neo General On Grade Data Sag Data Inlet Capacity Gin vs Depth D Table Wizard Paste Data 0 02 0 009 O04 0 024 Copy Data 006 0 045 0 069 01 00 012 0126 014 0 159 b 2 3 4 5 6 7 H DRAINS User Manual 2 51 November 2014 Figure 2 79 Inlet Capacity Data for an Individual Pit Select Default Data Base for New P
217. ered This procedures needs to be repeated for each design storm pattern required b Entering Single and Multiple ARR87 Patterns The setting up of standardised Australian patterns in the Rainfall Patterns dialog box has been demonstrated in Section 1 2 1 a in Figure 1 8 to Figure 1 11 with patterns being entered one by one It is also possible to enter multiple patterns in a single operation using 1987 intensity frequency duration I F D data from the Bureau of Meteorology website www bom gov au Multiple patterns can be entered by downloading data from the Bureau of Meteorology s site http reg bom gov au hydro has cdirswebx cdirswebx shtml shown in Figure 2 64 and pasting it into DRAINS 6 D hn eq bom gisu veto iher D 2S amp i Welccene te che IPD Pregam 1 i Ele Edi Wew Feweric Jools Hlp Welcome to the Rainfall IFD Data System This system produces an Intensity Frequency Duration design rainfall char and table between amp minutes and 72 hours in duration and Average Recurrence Intervals from 1 year te 100 years A coefficient table is also produced which you can use to derive the resulta or interpolate for values between those given NEW Calculate the Average Recurrence interval for the chosen location using a rain duration and total eagle ones hie ebet OPEM BA IFI Oe ee 18 beg We ie BORAH eto Pam cro ar T FRIAS BAE Sees eee eer NEARS Atoa B Coel Eton D Coet Eto Feo G Cae 2g49n3
218. es channels and streams In this process it integrates e design and analysis tasks e hydrology four alternative models and hydraulics two alternative procedures e closed conduit and open channel systems headwalls culverts and other structures stormwater detention systems and e large scale urban and rural catchments Within a single package DRAINS can carry out hydrological modelling using ILSAX rational method and storage routing models together with unsteady hydraulic modelling of systems of pipes open channels and and in the premium hydraulic model surface overflow routes It includes an automatic design procedure for piped drainage systems connections to CAD and GIS programs and an in built Help system Figure 1 1 shows areas where DRAINS can be used Highway Drainage Infill Design Property Drainage and OSD a eem a ae Drainage ae Asset Modelling Detention Hasins Rural Urban Catchment tladellir Subdivision i Drainage Urban Streets Flooding Figure 1 1 DRAINS Applications Three significant functions that are not included in DRAINS are a continuous modelling over long periods including wet and dry conditions b water quality modelling and c 2 dimensional unsteady flow modelling DRAINS is continuously being improved and expanded Although users need to adapt to new features and modes of operation in the program th
219. et Importing a DB1 data base Importing CAD files Importing data from spreadsheets Importing ESRI files Importing GIS data Importing ILSAX files Supplementary Importing Mapinfo files Area Contribution Information on DRAINS Inlet control Inlets Inputs to DRAINS Intensityfrequency duration relations Introduction Invar Display Figure 1 7 Help Window opened from the ILSAX Hydrological Model Property Sheet You should then click OK in the property sheet and the Hydrological Model Specification dialog box ensuring that Orange Soils is defined as the default model in the drop down list box at the top left corner of Figure 1 5 Next you must define the rainfall patterns to be used using the Rainfall Data option in the Project menu This opens the window shown Figure 1 8 in which you can set up a data base of rainfall patterns or hyetographs In this example two patterns are to be set up both of 25 minutes duration for average recurrence intervals ARIs of 2 years and 100 years corresponding to average intensities of 40 2 and 101 mm h For most design and analysis tasks in Australia the required rainfall data will come from Australian Rainfall and Runoff Institution of Engineers Australia 1987 or from updated intensity frequency duration data to be made available on the Bureau of Meteorology website www bom gov au DRAINS User Manual 1 7 November 2014 Rainfall Data Storm 1 B of Mame Antecedent m
220. ex shtml shown below NSW VIC QLD WA SA TAS ACT NT AUSTRALIA GLOBAL ANTARCTICA te Australian Government Tae Sy 3 Bureau of Meteorology Bureau Home Water Information Desian Rainfalls Intensity Frequency Duration Water Information Regulations Standards News and events About Intensity Frequency Duration The new Intensity Frequency Duration IFD design rainfalls mark the first stage of an extensive Australian Rainfall amp Runoff revision project While the new IFDs are derived from a longer and more extensive dataset careful consideration is needed when they are used with 1987 Australia Rainfall and Runoff AR amp R87 design flood estimation techniques Guidance has been provided by Engineers Australia AR amp R87 IFDs New IFDs 2013 Should be used for Existing design flood studies Probabilistic Rational Method Should be used for Sensitivity analyses for new design flood studies Revised Regional Flood Frequency analysis SS ee How were the new IFDs estimated How do the new IFDs compare to the AR amp R87 IFDs Can I use the new IFDs now New AR amp R probability terminology How do I incorporate climate change into the new IFDs Where can I find out more about the new IFDs More IFD questions and answers Feedback Subscribe to email updates about IFD Oe Unless otherwise noted all material on this page is licensed under the Crestive
221. f DRAINS and allows the hais New capabilities set by the hardware lock to be upgraded using passwords A aces eee Where an item in a menu list is followed by or b it opens another Roo ORANA menu a dialog box or property sheet Hoss Desi 2 3 Tools and Associated Components 2 3 1 General DRAINS provides 21 buttons in the Toolbar Djem S lt l alm ele e ae The first four buttons are for creating a new file opening an existing file saving a file and printing the Main Window duplicating functions in the File menu The last two buttons are the Zoom Factor function that is also available in the View window and the Pan function The remaining fifteen buttons can be used to draw components in drainage systems in the Main Window The first group of five are all nodes or junctions the next group of nine are links and the remaining sub catchment button provides a source of water as runoff derived from rainfalls If you hold your mouse arrow over each button a ScreenTip will appear to indicate its function Clicking on these buttons changes the cursor from an arrow to a pencil which is used to place components in the Main Window Holding down the Shift key while entering a component retains the pencil cursor after you have entered a component allowing you to add another component of the same type If you become stuck with the cursor still in pencil form when you no longer want to enter a component simply enter the component and
222. features that have become obsolete and have been deleted To avoid confusion these descriptions are not given here but the information remains in the DRAINS Help system to provide guidance when models created by earlier versions of DRAINS are revisited As DRAINS develops and new features are added there will be revisions of this manual available electronically from www watercom com au and on paper DRAINS User Manual W 1 November 2014 The authors contact information is Bob Stack Geoffrey O Loughlin Watercom Pty Ltd Anstad Pty Limited 15 Little River Close 72 Laycock Road Wooli NSW 2462 Penshurst NSW 2222 phone fax 02 6649 8005 02 9570 6119 fax 02 9570 6111 0438 383 841 bobstack watercom com au geoff oloughlin tpg com au DRAINS User Manual W 2 November 2014 Da 1 INTRODUCTION TO DRAINS 1 1 Outline 1 1 1 Description DRAINS is a multi purpose Windows program for designing and analysing urban stormwater drainage systems and catchments It was first released in January 1998 and is marketed by Watercom Pty Ltd based in Wooli NSW DRAINS can model drainage systems of all sizes from small to very large up to 10 km using sub catchments with ILSAX hydrology and greater using storage routing model hydrology Working through a number of time steps that occur during the course of a storm event it simulates the conversion of rainfall patterns to stormwater runoff hydrographs and routes these through networks of pip
223. fficient for roofs is assumed to be 1 0 and that for impervious surfaces at ground level to be 0 9 Only a property site itself is considered in these calculations The rational method formula is expanded to allow for the three surface types Q I C A CA C A 3600 Equation 5 11 where A Aj and A are the areas of roofs impervious areas and pervious areas in the sub catchment being considered In calculations the time of concentration is fixed at 5 minutes All methods require intensity frequency duration I F D data that is entered in the Rational Method Rainfall Data property sheet opened from the Rainfall Data option in the Project menu 5 3 5 The Extended Rational Method A number of methods have been developed for extending the rational method to produce hydrographs usually by assuming a triangular or trapezoidal shape In the US a Modified Rational Method Poertner 1981 has been applied in many locations This produces hydrographs corresponding to uniform rainfall blocks of various durations which can be used to model detention basins in the same way that can be done using Australian Rainfall and Runoff design rainfall patterns DRAINS presents a variation on this method named the Extended Rational Method ERM which is available if the rational method is enabled in the hardware lock used It was introduced to meet the needs of users who wish to develop hydrographs that are consistent with Rational Method flowra
224. ficients according the specified impervious and pervious areas using a much simpler procedure than that applied in the ILSAX model The run results are similar to those from the ILSAX model except that peak flowrates are produced but no hydrographs of flow so the results cannot be used to model detention storages as ILSAX and other hydrograph producing models can To meet the needs of users wanting to apply the rational method to detention basin calculations an extended rational method ERM has been provided in DRAINS This can be selected from the Hydrological Models property sheet as shown below Default Model for Design and Analysis Runs G pmea EAM Separate areas Lymea Rational Method Grimea ERM Separate areas Gymea ERM Total areas The parameters required are shown in Figure A 12 The ERM determines a runoff volume based on the runoff coefficients supplied and then uses the same time area routing procedure as the ILSAX model to produce hydrographs Consequently hydrographs can be produced from ARR87 rainfall patterns but because of the different infiltration assumptions these will differ from ILSAX hydrographs produced from the same rainfall patterns Extended Rational Method Mod Model Nane Gymea ERM Separate areas Rational Method Procedure Impervious Area C10 Value 0 9 a Pervious Area C10 Value 0 51 m These C10 values are 10 year ARI runoff coefficients Thep will be adjusted automatically
225. for Premium Hydraulic Model Calculations mmj Overflow Route OF 2 _ 5 Basic Data Overflow Weir Properties Cross Section Data Weir type Rectangular broad crested The sag pit is located in the gutter at a low point sag along the road Water ponding above the sag pit can spill over the road centre line The road centre line forms a parabolic weir crest You define the along the road centre line Horizontal distance from low point im 30 Height above low point m 0 3 Note This data is used in the premium hydraulic model only The basic and standard hydraulic models assume zero depth over the weir at a sag pit Figure 1 45 Specification of Overflow Weir for a Sag Pit In Step c when a Design run is made and followed by an analysis the results appear similar to those obtained with the ILSAX hydrology as shown in Figure 1 43 A difference is that only peak flows are generated rather than a full hydrograph as shown in Figure 1 32 and Figure 1 35 so that detention storages cannot be modelled using the rational method Steps d and e proceed in the same manner as with the ILSAX hydrology An Analysis run can be made to determine major storm effects but this will not be as accurate as major system results derived using hydrographs in the ILSAX model The run proceeds with DRAINS adding invert levels for overflow routes The cross sections and roughnesses specified for overflow routes are used with the
226. for the reservoir which can be orifices pipe systems weirs or combinations of these DRAINS allows for separate height outflow relationships for low and high level outlets of the type shown in Figure 5 30 Routing is performed with a combined relationship but outflows via high level outlets such as diversion weirs can be directed out of the system or to reaches other than the one immediately downstream Weir Flow Q C Wy hy i Entrance and Bend Losses y2 Ke kp Ps 2g i ti L V Friction Loss f 5 5 H l V Exit Loss 1 0 2g Length L Diameter D oo Darcy Weisbach Friction Factor f 2gH Ke ky thE 1 0 Pipe Flow Q AV 7D Box Culvert Orifice Control Q A V C B D 2g H C D Figure 5 30 Detention Basin Outlets DRAINS User Manual 5 38 November 2014 5 8 2 Overflows from Basins Low level outlets from basins consist of culvert or drop pit pipe systems The outflow rate for these is dependent on the headwater and tailwater levels and energy losses through the pipe system Height outflow or depth discharge relationships for various kinds of outlets are given in textbooks and manuals on hydraulics The equations shown in the box below are used for calculating height outflow relationships in DRAINS for detention basins culverts and headwalls Equations for Determining Height Outflow Relations used in the Detention Basin Culvert and Headwall Calculations Outlets with Circ
227. format This includes a background showing streets lot boundaries and other information Other data obtainable from CAD drawing files such as sub catchment areas will have to be entered into property sheets or via a spreadsheet For investigation of established drainage systems data is likely to be available in a number of forms paper plans CAD drawings spreadsheet tables data bases from GIS systems and aerial photographs DRAINS can accept ESRI ArcView ArcInfo and ArcMap files and MapInfo files A background can be imported as a DXF file and spreadsheets can be assembled into a form accepted by DRAINS DRAINS User Manual 3 1 November 2014 3 2 2 Importing DXF Files a New Systems Where a drainage system has been drawn in a drawing package or digital terrain model it can be imported into DRAINS in DXF format This is one of the oldest drawing formats which can be created in almost all technical graphics packages Newer formats such as DWG the widely used AutoCAD binary format can be converted to DXF format before transfer to DRAINS The external software package must include three layers e one for pits with the location of each pit marked by a circle e one for pipes with pipes shown as lines and e abackground which may show street boundaries cadastral information and contours Other layers can also be present but will not be used Lines poly lines and arcs on the background layer will be imported into DRAINS as a bi
228. from the list box b the percentage of flows estimated to come from the downstream sub catchment and c a flow path channel slope With the storage routing model option shown in Figure 2 29 DRAINS uses the cross section in its kinematic wave calculations In both procedures it will calculate flow characteristics such as depths and widths assuming that normal depth occurs in the flow cross section at the slope indicated DRAINS User Manual 2 20 November 2014 DRAINS can define flow characteristics at a selected critical location which may be at a pit receiving overflows from this overflow route combined with flows from its local sub catchment This location could also be just downstream of the pit from which the overflow occurs The position is effectively defined by the percentage of the downstream catchment s flow that is carried by the cross section which must be entered into the property sheet in Figure 2 30 Figure 2 31 shows how a downstream sub catchment may contribute to flows Here the critical point is the downstream pit which is ina sag An estimated 65 of Catchment 2 drains to this point on the left side of Pit 2 N Land Critical Loc ation at Pit 2 Figure 2 31 Effect of a Lower Sub Catchment upon Overflows If the property sheet for the overflow between Pit 1 and Pit 2 specifies a percentage of downstream catchment of 0 the flowrate displayed in the results will be the overflow from Pit 1 This
229. fv h Figure 5 26 Pit in Swale A similar procedure applies for sag pits The DRAINS wizard shown in Figure 5 27 only operates for grated inlets This requires information on grate dimensions For kerb inlets or combination kerb inlet grate inlets you can use the generic spreadsheet supplied to DRAINS users to develop relationships that can be pasted into the DRAINS pit data base The calculations associated with these methods produce results that match laboratory results on pit capacities well in some cases but rather poorly in others This issue has been studied by Pezzaniti O Loughlin and Argue 2005 who produced the assessments of the accuracy of the HEC22 procedures for on grade pits shown in Table 5 20 This can be used as a guide to adjusting relationships produced by the HEC22 procedure Adjustments can be made by copying the relationship produced to a spreadsheet modifying this as required and then pasting it back into the Pit Data Base table Using these procedures it is possible to derive inlet capacity relationships for all types of pits including unusual or modified ones DRAINS User Manual 5 30 November 2014 Sag Pit Wizard This wizard wall fill in the Depth vs Inflow Capacity table using the weir equation for low depths the orifice equation for high depths and an intermediate pone value in the transition range ret FHWA Circular 12 Pavernent Drainage Pit perimeter accepting inflow m i 4
230. ge system Ifa free outfall is specified the starting point for this upwards projection at each time step is the higher of the pipe s normal and critical depths for the current flowrate If a tailwater level higher than these depths is specified in the Outlet Node property sheet this becomes the starting level Outlet Node Name Outlet Surface level m 24 4 Storm ais oft a ARB 100 year 1 hour storm average 112 mm h Cancel Help During this storm the outlet Note Changing the outlet water discharges freely to atmosphere level changes it forthe current storm only Click on the storm scroll arrow to change itfor other storms Outlet water level mi od for storm 1 Comments Figure 2 10 Outlet Node Property Sheet Intermediate nodes connecting pipes open channel systems and overflow routes appear as shown in Figure 2 11 with a surface level required Nodes that link stream routing reaches in a storage routing model have the same property sheet but no surface level is required only the node name A baseflow or user provided inflow hydrograph can be entered at each node by clicking on the corresponding buttons in the node property sheet This will open property sheets similar to those in Figure 2 8 and Figure 2 9 Name Nd Surface Level 703 5 Cancel Baseflowy Inflow Hydrograph Figure 2 11 Property Sheet for an Intermediate Node 2 3 4 Pipes The Pipe property sheet shown in Figur
231. ged if the pipes in the CAD drawing are drawn from the bottom up Lettering for features such as street names can be brought into DRAINS from a CAD file if it is in an acceptable format If AutoCAD is being used text in the Standard style on a single line created using Draw Text PB Single Line Text can be transferred f You can ether replace the existing background layer or add the It is possible to import a new background or to imported data to it You should only add to the existing laper if the new exchange the current background with another background i different eg adding contours to an existing layer Using the File Import Import DXF containing property boundaries background option brings up a dialog box from which a DXF file can be opened When a file is B selected the window shown to the right appears f Add to existing background Replace existing background DRAINS User Manual 3 3 November 2014 3 Untitled DRAINS les File Edit Project View Draw Run Help osm S ole lml m vvu oa Qley H E m Ny 22 nh mP BN 72927 M 227 7277 Edit Data Copy Shape View HGL Graphs View HGL Tables Delete Press F1 for help Figure 3 5 Imported DXF File Information Note that if you replace a background it does not open the dialog box shown in Figure 3 3 and will not transfer pits and pipes All layers in the replacement CAD file will be shown For example
232. gle represents the screen Trim Drawing Edges size Placing this mask in a certain position and clicking sets the screen to that position as shown in Figure 3 22 Last Run Report Animation Figure 3 18 View Menu c Zoom There are three zoom options for enlarging or reducing the image in the Main Window The Zoom Factor which is also available through a button on the Toolbar changes the cursor to a magnifying glass which you should place over the area to which you wish to zoom Clicking on this opens the dialog box shown in Figure 3 23 in which you can nominate the magnification If you accept the default value of 1 5 an enlarged presentation is obtained Entering a factor less than 1 reduces the size of the system but the size of lettering remains the same DRAINS User Manual 3 13 November 2014 Customise Drawing Text For pipes show C Name Peak flow C Diameter C Length C Slope C Length and Diameter C US and D S Invest Level C Peak U S and D S AGL C Minimum cover depth C Mothing For imegular channels show C Name j Peak flow C Length C Nothing For prismatic channels show Name Freak flow Length Slope US and OS Invent Level Moth ing o a ie loa For catchments show f Name fe Peak flow C Nothing For overiow roues show Name w Peak flow C Mas width of flow C Volume camed Nothing a OF Cantal Help Hide zero flows For nodes show Mam
233. graphs 2 0 008 0 8 09 ad 0 006 1 0 004 1 1 e 12 TE 0 002 ie 0 Ls es 0 20 40 60 80 100 120 EB Time mins Figure 1 32 Hydrograph and Hydraulic Grade Line Results for a Minor Storm xl el 9 7 Booki Microsoft Excel GSA Home Insert Page Layout Formulas Data Review View Add Ins Acrobat 7 co es Ts ee bd r m I a B D E j S A E a n S j Q i Expand Formula Bar Ctrl Shift U 1 PIT NODE DETAILS Version 11 lo 2 Name Type Family Size Ponding Pressure Surface Max Pond Base Blocking x y Bolt dowr id Part Full Inflow 3 Volume Change Elev m Depth mjinflow Factor lid Shock Los Hydrograph 4 cum Coeff Ku cu m s 5 Pit4 OnGrade NSW RTA SA1 Type 2 3 lor 4 5 22 1 0 0 9 697 244 242 No 21xKu No 6 Pit5 OnGrade NSW RTA SA1 Type 2 1 lor 1 217 0 0 18 516 236 005 No 11xKu No 7 Outletl Node 21 0 32 858 235 981 16 Data for 8 Pit1 OnGrade NSW RTA SA1 Type 2 3 lor 4 5 22 5 0 0 4 693 248 646 No 31xKu No A e 9 Pit2 Sag NSW RTA SA1 Type 10 0 5 22 3 0 2 0 0 5 9 084 244 232 No 41xKu No Pits and 7 10 Pit3 OnGrade NSW RTA SA1 Type 2 1 lor 1 5 22 0 0 9 109 236 008 No 5 1x Ku No 11 Outlet2 Node 21 5 0 32 928 244 089 15 12 Outlet3 Node 21 0 4 818 217 298 24 13 14 DETENTION BASIN DETAILS 15 Name Elev Surf Area Init Vol c Outlet Tyg K Dia mm Centre RL Pit Family Pit Type x y HED CrestRL CrestLengid 16 E 17 SUB CATCHMENT DETAILS 18 Name Pit or Total Paved Grass Supp Paved Grass Supp Paved Grass Supp Paved Grass Supp
234. harges and stormwater infiltration can be modelled using overflow routes with suitable water level discharge relationships but it is best to use the specific pumping and infiltration methods provided Elevation discharge relationships can be calculated in a spreadsheet and pasted into the Overflow Route property sheet using the Paste Table button in Figure 2 39 2 3 8 Special Weirs and Orifices Two new components in DRAINS the orifice Ej and the weir are only available with the premium hydraulic model These facilitate the modelling of complex detention basins that have multiple orifice or weir outlets that can connect to various outlet points with different tailwater levels With the standard hydraulic model it is possible to model a single pipe or orifice controlled outlet and multiple weirs that are located above tailwater influences However it is difficult to model a second pipe or orifice even when this leads to a free outfall The new components make such modelling easy and accurate under complex tailwater conditions Figure 2 40 shows an example named Premium Detention Basin drn that has two orifice and two weir outlets The orifice and weir links can be bent or kinked to allow several links to go to a common point This can be done by clicking on the link so the handles appear at the ends placing the mouse pointer on the line holding down the mouse button and moving the pointer ey Premium Detention Basin drn DRAINS
235. hat are consistent with the I F D duration curves of the design rainfalls Using these patterns with the ERM rather than the The volumetric runoff coefficient the ratio of volume of runoff to volume of rainfall obtained from a pervious area with the ERM will be the same as the C1 coefficient supplied adjusted by a frequency factor The validity of this has been checked using data collected at the Jamison Park Gauging Station in Western Sydney as shown in Figure 5 16 Results from 80 storms shown in indicate that this is reasonable for this locality Peak flow coefficients were derived assuming a time of entry of 20 minutes 5 4 Storage Routing Models Traditionally storage routing or runoff routing models such as RORB RAFTS and WBNM have been used for flood studies for larger rural catchments and somewhat smaller semi urban catchments These models were introduced in the 1970s as computer models became more widely used than previously and methods for modelling urban areas became more important Volumetric Runoff Coefficient 0 00 0 20 0 40 0 60 0 80 1 00 1 20 Peak Flow Runoff Coefficient Figure 5 16 Jamison Park Volumetric vs Peak Flow Runoff Coefficients Previous models notably synthetic unit hydrograph procedures provided a flow estimate at the outlet to a catchment By dividing the catchment into sub areas the storage routing models provided flood estimates at several points throughout the stream system They also allowed
236. hat sometimes arises is the application of the ILSAX model to rural catchments This is uncertain because the ILSAX model has not been calibrated using rural data The calibrations made to urban data described in Chapter 5 of the DRAINS User Manual give confidence that the model will work well where a catchment has a significant impervious portion say 20 or more and a man made drainage system However for largely rural catchments with natural drainage systems the results are uncertain DRAINS User Manual A 11 November 2014 70 50 s 50 35 gt c 40 S 30 es S 25 F 30 20 LL LL 20 15 io 0 0 1 2 3 4 1 2 3 4 AMC Values AMC Values Toowoomba Queensland Mean AMC 3 5 Perth WA Mean AMC 2 8 Figure A 10 Histograms of AMCs for Daily Rainfalls 5 Days prior to the 100 Highest Daily Rainfalls on Record This may be overcome by calibrating the model to peak flow estimates from Chapter 5 of ARR87 Book 4 Section 1 in the 1998 version such as the NSW Probabilistic Rational Method The main DRAINS parameter that can be changed to alter flows is the time of concentration for pervious areas but other parameters such as the AMC and depression storages may also be changed It will be necessary to analyse a number of storm durations to obtain a worst case flowrate Where DRAINS is applied in rural conditions the procedure should be outlined and the assumptions regarding parameters and results made clear in
237. hat the required DRAINS pipe and pit relationships appear Click the Read Drains database button and check the displayed information and the pit group separator Separators or are used in the names contained in different DRAINS pit data bases If the data is not what you want return to Step a c Then open the window Design Drainage Sewer Drainage Network Editor shown as Figure 3 15 From this you can check define sub catchments pits pipes and overflow routes using 12d procedures Set appropriate defaults and use the Set Pit Names button to provide a set of unique pit names Then press Set Pit Details and Set Catchments and nominate the Regrade Pipes option d Now the transfer can be made using the Import Export button on the Drainage Network Editor which opens the dialog box shown in Figure 3 16 For I O format select Drains Clipboard Ver 5 ILSAX or Drains Clipboard Ver 5 Rational depending on the hydrological model you are running in DRAINS Click the Run button DRAINS User Manual 3 10 November 2014 E Drainage Network Editor Drainage Network Edit ox Drainage model D PIPE ROAD Catchment p Pipe DEFAULTS GLOBAL Catchments flowing to current pit Set 1 Set 2 set 3 ne import i hd Cotiveenk PENON MENTRE ue T ZETEMA Catchment area 0 069702775 IO file name clipboard txt Percent impervious b ooo i BARDEEN 7 Impervi
238. he DRAINS model can be created This will appear in the same form as Figure 3 10 To make a transfer you will need to place all the files to be transferred into the same Windows folder set up a DRAINS model with the ILSAX hydrological model and pit and pipe data bases that you require and then use the File gt Import gt MapInfo MIF files option which will display the following message C You are about to import data from a set of 6 Mapinfo MIF files These P include data for nodes including pits etc pipes pipe survey data services crossing pipes catchments and overflow routes Each MIF comprises a set of 2 files with the extensions MID and MIF so that a total of 12 files are needed You can select any one of these to open and DRAINS will read all 12 If there ts a dxf file of the same name a background layer will be imported from this file The next step ts to specify the file name Continue After you enter Yes you must select one of the MapInfo MIF files to be transferred as shown in Figure 3 13 The transfer will then take place and the pits and pipes will come into view in the same form as Figure 3 11 DRAINS User Manual 3 8 November 2014 Look in i DERE bi gt Date modified Type 2 Oldtown_Catchments mit 12 01 2011 12 44 MIF File 7 Oldtown_Nodes mit 12 01 2011 12 44 MIF File i 2 Oldtown_OverflowRoutes mif 12 01 2011 12 44 MIF File Desktop 2 Oldtown_Pipes mif 12 01 2011 12 44 M
239. he background to the drainage system which can be transferred at the same time For nodes a table with the following 13 headers for columns or fields are required DRAINS User Manual 5 44 November 2014 Shape the nature of the object point any name up to 10 characters DRAINSid an internal number used by DRAINS to connect nodes and link this must be kept blank Family the pit family corresponding to a family in the pit data base in the DRAINS model to which the data is being transferred or N A 6 Size i a pit size within the nominated pit family or N A o o o 8 Ku the pit pressure change coefficient Use N A for simple nodes 9 SurfaceEl the surface elevation at the node m BoltDnLid a Yes No or N A as to whether there is a bolt down lid In a shapefile exported from DRAINS there may also be Hgl_XXXXX optionally one or more HGL levels taken from a series of runs for Different storms XXXXX takes different values For pipes a table with the following 12 headers for columns or fields are required the nature of the object line or poly line any name up to 10 characters 3 DRAINSid an internal number used by DRAINS to connect nodes and links this must be kept blank 6 DownStrmiL__ the downstream invert level m S Ce a the DRAINS model to which the data is being transferred oe the nominal pipe diameter mm corresponding to diameters in the pipe type nominated
240. he channel should be defined as an irregular open channel as explained in the following section to include overbank flow areas Where an overflow from a channel will cause a breakout that follows a different path to the main stream special ways of modelling the separation of flows are required see Table 2 2 in Section 2 3 17 DRAINS User Manual 2 28 November 2014 Channel from Node Z2 to HW X a y ES Cancel Scale off Length D rm Z Help w ml Z Channel iz roofed Mame Chri fe Upstream invert elev m 460 5 Length ra 0 Downstream invert elev m 475 5 Manning s n 0 03 Slope 2 10 00 Hotes Figure 2 43 Prismatic Open Channel Property Sheet 2 3 11 Irregular Open Channels a General This component with the property sheet in Figure 2 44 allows you to set up stream reaches to model a stream or channel with varying cross sections and slopes It can also be used to model closed and open conduits with cross sections other than circular rectangular or trapezoidal The information required differs between the obsolete basic hydraulic models calculations and the unsteady flow calculations used in the standard and premium hydraulic models b Basic Hydraulic Model Calculations It is necessary to define channel reaches over which flowrates are the same and to define for each reach at least two cross sections at the upstream and downstream ends of the reach At each cross section
241. he length of the overflow route and invert levels at each end of the flow path are required DRAINS uses this with information from the Cross Section Data page to route flows along the route If an overflow route leaves a sag pit you must also specify control weir information in a third Overflow Weir Properties page of the overflow route property sheet shown in Figure 2 27 DRAINS User Manual 2 17 November 2014 Overflow Route OF K oe rf _1 Time estimate Basic Data Cross Seci used with basic or standard OF Kal calculations Flow Routing in Basic and Standard Models f Simple Translation no attenuation C Kinematic Wave Name Travel Time mins 0 5 Reach Length m 33 8 Scale off Length The kinematic wave option is Extra Data fo 4 only available when storage routing calculations are enabled Length of overflow path used with basic or standard hydraulic calculations and with kinematic wave routing Invert levels at the ends of the overflow route these only appear if premium hydraulic model calculations can be made cones te Figure 2 26 First Page of Property Sheet for Premium Hydraulic Model Calculations Overflow Route OF K5 De Basic Data Overflow Weir Properties Cross Section Data Weir type Rectangular broad crested Parabolic broad crested C You specify The sag pit is located in the gutter at a low point saq along the road Water ponding above the sag pit can s
242. he pit data base in the DRAINS model to which the data is being transferred or N A a pit size within the nominated pit family or N A 6 PondingVol _ the volume of water that can pond over a sag pit m o o 7 the pit pressure change coefficient Use N A for simple nodes 8 SurfaceEl____ the surface elevation at the node m O Z o Z o SS O 9 PondDepth _ a Colebrook White or Manning s roughness coefficient hi BoltDnLid a Yes No or N A as to whether there is a bolt down lid In a MID file exported from DRAINS there may also be HGL_XXXXX optionally one or more HGL levels taken from a series of runs for Different storms XXXXX takes different values for example 5 Yr For pipes the table includes the following 11 or more headers any name up to 11 characters 2 DRAINSid an internal number used by DRAINS to connect nodes and links this must be kept blank 6 Slope_pct thepipesiope S DRAINS model to which the data is being transferred the nominal pipe diameter mm corresponding to diameters in the pipe type nominated 9 Roughness a Colebrook White or Manning s roughness coefficient New or NewFixed or Existing the number of parallel pipes usually 1 In a MID file exported from DRAINS there may also be Flow_XXXXX__ optionally one or more flowrates from different storms designated by XXXXX Ve X
243. her six MID files are also produced After a name is entered it will be necessary to nominate the projection to be used if the data has not been brought in from Maplnfo files This can be done in the dialog box shown in Figure 3 58 that appears This has a similar format to the equivalent window in Maplnfo Choose Projection Map Grid of Australia 1994 MGA 94 Category Members Figure 3 58 Nomination of Projection The process is then complete if there are no results If results are available a dialog box similar to that shown in Figure 3 51 appears A suitable name should be added describing the results such as 10Yr for a 10 year average recurrence interval storm A background in the DRAINS model will be transferred with the MapInfo files If there are any problems with the projections these can be overcome by editing the ASCII MIF file inserting a line giving the appropriate projection The transferred files can now be viewed in MapInfo as shown in Figure 3 59 DRAINS User Manual 3 34 November 2014 a MapInfo Professional Kirrawee2_Nodes Kirrawee2 i ipes Ma ES File Edit Tools Objects Query Table Options Map Window Help Dor S gt S 5 2 Name Pipe B 1 DRAINSid 10 Length 16 50 Zoom 0 5047 km Editing None Selecting None Figure 3 59 Display of Data transferred to MapInfo 2Yr and 100Yr are added to headings as a suffix
244. ic models Some are available to all purchasers while others can be purchased as optional add ons The choice of hydrological model will depend on the task to be undertaken with the model and by the likelihood of acceptance of the model by approval DRAINS User Manual 4 19 November 2014 authorities or assessors Comparisons of alternative models are presented in the guidance on the DRAINS Viewer that is included in Appendix A All hydrological models except the rational model produce hydrographs which are necessary for modelling detention storages and complex networks The ILSAX and storage routing models RORB RAFTS and WBNM are backed by testing programs in which their performance has been tested against gauged rainfall and runoff data The rational method models have not been extensively tested but have been the most commonly used models in many applications Some authorities consider them to be acceptable benchmarks The extended rational model included in DRAINS is an extension of the rational method The storage routing models are the accepted methods of modelling broad scale urban catchments and can cope with the hydrological effects of urbanisation The various models produce different flow estimates due to a use of different rainfall data notable I F D statistical relationships and Australian Rainfall and Runoff patterns b models being derived for different purposes scales of operation pipe system sub catchments compared to large
245. ics Pentech Press London Watson M D 1981a Application of ILLUDAS to Stormwater Drainage Design in South Africa Report 1 81 Hydrological Research Unit University of the Witwatersrand Johannesburg DRAINS User Manual R 3 November 2014 Watson M D 1981b Time Area Method of Flood Estimation for Small Catchments Report 7 81 Hydrological Research Unit University of the Witwatersrand Johannesburg Wilkinson A 1995 Rainfall Variability Investigations at Hewitt Penrith 1994 95 Undergraduate Project School of Civil Engineering University of Technology Sydney XP Software 2000 XP RAFTS User s Manual Version 5 1 Reference Manual Canberra DRAINS User Manual R 4 November 2014 INDEX Xa During Design runs options 2 10 12d 1 4 3 35 4 12 12d file transfers 3 10 ACT pits 5 24 Advanced Road Design 1 4 3 35 Alignment of pits 1 12 Allowable connections of components 2 37 Allowable ponding depth 1 15 AMC 4 7 Analysing established systems 4 14 Analysis information 4 14 Antecedent moisture condition 1 8 Antecedent moisture condition AMC 5 10 Areally varying rainfall intensities 2 16 ARI 1 7 ARR Wizard 1 25 ARR2013 Rainfall procedures 2 40 Assessing hydraulics A 19 Assessing hydrology A 8 Assessing models A 7 Assessing rainfall inputs A 7 Asset management 4 17 Australian New Zealand Standard AS NZS 3500 3 2 5 17 Australian height datum AHD 2 4 AUSTROADS Waterway Design manual 5
246. idence that the submitted design meets the overall purpose A 3 2 Property Drainage Systems For stormwater drainage systems on private properties DRAINS can be used to design gravity and pumped pipework and simulate the behaviour of detention and retention storages Table A 1 notes the DRAINS User Manual A 3 November 2014 required and optional information that is normally needed by reviewers The optional items may be required for assessment if a systems are complex b consequences of failure are significant or c precise documented design is needed Table A 1 Typical Requirements for Assessing Property Drainage Systems Plan view of stormwater drainage system A concept plan drawn to scale but not in showing locations of downpipes above and detail should be sufficient for most purposes below ground pipelines storages and other features Plan and section views of on site detention The storage volume provided and sizes of tanks and surface storages showing positions outlet controls such as orifice plates should be and levels of inflow and outflow pipes and noted discharge control pits Results of on site detention calculations The amount of information required depends including rainwater tanks where these are on the requirement of the council or approving integrated with OSD storages and allowance authority If the method used requires storage for stormwater infiltration where this is routing DRAINS outputs provide the p
247. if the Brisbane background is read in again the contours and pipes will appear in the background You must be careful that the replacement file only contains the layers that you want This will probably involve the creation of an additional CAD file containing only those layers that you want to display If you have a DRAINS model without a background you will be able to insert a background provided that it has a similar extent in x y coordinates to the coverage of the x y coordinates of the pits and nodes used in the model which are displayed in the spreadsheet data output Backgrounds can be inserted into models that include saved results 3 2 3 Spreadsheet Imports Information about a drainage system can also be imported from a spreadsheet file Since this file will usually be created by outputting information from a DRAINS file both the spreadsheet output and input processes are described later in Section 3 5 4 of this chapter Some sets of information can be pasted into DRAINS property sheets for rainfall patterns hydrographs pits detention basins headwalls and culverts as columns from a spreadsheet A DRAINS Utility Spreadsheet and a Generic Pit Inlet Capacity Sheet are available to DRAINS Users with the former being on the www watercom com site Information from these can be pasted into DRAINS as shown in Figure 3 6 3 2 4 GIS File Imports a Importing ESRI ArcView Files This process enables you to import data into DRAINS fr
248. ill drop by the amount of the head loss for the pit which can be expressed as DRAINS User Manual 5 34 November 2014 V hi k Equation 5 22 29 where his head loss m k is the head loss coefficient dimensionless Vo is the full pipe velocity in the outlet pipe from the pit m s and g is acceleration due to gravity 9 80 m s More importantly for design the pressure change is given by V2 hy ku 2g Equation 5 23 where his head loss m and k is the head loss coefficient dimensionless also expressed as K Generally k is positive with the HGL dropping down but it is sometimes negative with the line rising due to the downstream pipe having a larger diameter and slower velocity than the upper one This has been termed static regain It is assumed that head losses and pressure changes take place at the centre of the pit while actual losses occur mainly in the outlet pipe just downstream of the pit Where significant turbulence occurs in the pit the water level may be higher than the incoming HGL A higher factor kw may be used in place of k to establish water levels where information on these factors is available A different factor to the main branch k may also be applied to side branches There are an infinite number of combinations of factors affecting the magnitudes of k and ku These include relative flows in upstream flows the local inlet and the downstream pipe the rela
249. in a system with conditions being calculated at multiple points in longer conduits The time or t dimension relates to the time steps used While results are reported at fixed times calculations can be carried out at smaller time intervals The main quantities being calculated are water elevations H and flowrates Q The main calculation involves the solution of the matrix equations to determine H and Q values at all locations at each time step during the simulation As well as the core calculation procedures this involves the determination of states at many boundaries in the system such as pits where water enters and outflow locations Water or HGL levels are presented at pits and nodes and also appear on some plots of pipe overflow route and open channel long sections The flowrates displayed apply at the centre of the link The DRAINS hydraulic calculation procedures permit two outlet pipes to be specified for each pit and can model looped or branching pipe systems where there is a bifurcation with two pipes coming out of a pit The premium hydraulic model permits two or more overflow routes from sag and on grade pits so the DRAINS User Manual 45 November 2014 invert levels of overflow routes from a pit can be at different levels This allows modelling of situations that cannot be adequately modelled using the basic or standard models e g overflow from an on grade pit down a gutter and across the road crown d Pit Modelling As f
250. ine the exact positions and levels of system components including surface levels of pits e invert levels of pipes including if possible those in sealed pits and junctions e lengths of pipes e floor levels of houses and businesses and driveway levels where flows may enter properties and yard levels where ponding may occur DRAINS User Manual 4 14 November 2014 Techniques such as GPS measurements and LIDAR aerial laser scanning supplemented by conventional surveying can be used to obtain large amounts of levels efficiently Inspections are needed to define many aspects of drainage systems such as low points on roadways and likely overflow paths It is likely that the same areas may have to be inspected two or three times during modelling to define drainage components and paths exactly Information can also be sought from residents about their experiences of flooding during these visits Closed circuit television CCTV investigations can provide detailed information on pipes and defects such as erosion cracks and faulty joints If resources are available the drainage system may be gauged to record storms rainfalls and corresponding drainage system flows that can be used to calibrate models Rainfalls are usually recorded by tipping bucket raingauges and pipe and channel flows by magnetic or laser Doppler flow meters Gauging for a period of at least 3 months will probably be necessary When the model is run with recorded data the
251. ing its full pipe and open channel network calculation procedures The spreadsheet documentation provided by DRAINS is very useful for recording results which can be separated into worksheets and suitably tagged When analysing very large systems say 500 pipes and over computation times can be quite long with multiple storms It is therefore necessary to plan the analysis work starting with storm events likely produce the highest flowrates Once the system has been refined final runs can be made with a wider range of rainfall patterns of different average recurrence intervals and durations Once a working model has been established the likely flowrates heights of storages flooding impacts and resulting damages can be assessed Flooding trouble spots can be identified and remedial works can be considered The initial DRAINS model can then be varied to produce a number of models for assessing different remedies In some cases the remedies will interact with each other some reinforcing the beneficial effects of other remedies others diminishing these This makes the consideration of options quite complex The rational method analysis procedure should not be used to simulate the behaviour of existing systems since the various flow peaks calculated can occur at different times and the flowrates obtained from combining peak flows are approximate This procedure should only be used to check newly designed systems The extended rational method can
252. ing the length of one pipe The other components of the system pits sub catchments overland flow paths and outlets can then be added DRAINS User Manual 1 11 November 2014 3 Untitled DRAINS File Edit Project View Draw Run Help Dsm lalala eluea ala Figure 1 16 More Complete Orange Drainage System Drawing arm The background is an image created from vector objects lines polylines and arcs in the nominated layer of the CAD file It can be switched on and off and its colour can be changed using options in the View menu 2 AutoCAD LT Orange Base dxf File Edit View Insert Format Tools Draw Dimension Modify Window Help 2 8 of So Background v D ByLayer v ByLayer v ByLayer v Van Sm J 2d 6m Eee Of Gm Pipes Of GO Pits circles H O GONOOLSN WANCELANEPACHBOES gt lt Cee SOQ 4 BOBT O SO UEhERABACARSAQ HE WW 17 8435 266 6420 SNAP GRID ORTHO POLAR OSNAP LWT MODEL Figure 1 17 CAD Display showing Pipe System Layout and Background Data for parts of the drainage system can be entered and edited using property sheets that appear when you right click a component and select Edit Data from the pop up menu as shown in Figure 1 20 The property sheet for Pit 1 is shown in Figure 1 21 This has two pages the first with pit properties and another optional page for factors to be applied if pit pressure change coefficients
253. ints throughout the catchment In 1979 they were followed by the WBNM Watershed Bounded Network Model of Michael Boyd David Pilgrim and lan Cordery Initially these models were run on mainframe and mini computers RAFTS Runoff Analysis and Flow Training Simulation an enhanced version of RSWM was released in 1983 and sold commercially by Willing amp Partners later WP Software and XP Software This includes continuous modelling processes as well as the storage routing model discussed here A version for PCs was released in 1987 APC version of RORB was released in 1988 WBNM was revised in 1987 and a new version was produced by Michael Boyd Ted and Rudy VanDrie in 1994 which modelled urban catchments WWBNM2000 introduced in 1999 used a different structure to earlier models and added many features Storage routing calculations are carried out over a series of time steps with the information obtained from solving equations at one time step being used as an input to the next step Each of the models available in DRAINS has been developed on different principles RORB performs calculations based on the equation S k k Q kg l l Q Equation 5 12 where Sis storage m ks and m are parameters with m being in the range 0 65 to 0 85 k is a routing factor for a particular sub catchment being the ratio of the stream length running through that sub catchment l and the average flow distance from sub catchments to the
254. ion contained in the drn file a set called Drains db1 is contained in the C Program Data Drains folder This is set that is applied when DRAINS is first opened The regional sets of pipe pit and overflow route data for New South Wales Queensland and other states are stored as db1 files in the C Program Files Drains Program folder along with the Drains exe file These sets can be installed using the Default Data Base option in the Project menu which copies these to Drains db1 lt is important that users determine what they require before starting a project as it may be awkward to change the available options later DRAINS User Manual 4 1 November 2014 4 2 4 Processes As shown in Figure 4 1 you can operate DRAINS through a number of processes such as a Data entry and file storage b Performing calculations d Changing or correcting data and re running calculations c Inspection and possible storage of results e Transferring data and results to files and other programs CatchmentSIM Import Import data data DRAINS model in computer memory from keyboard and other sources displaying this on screen Save Open file file Data stored in binary file 12d Digital Terrain Model Autodesk LD Or Civil Design Spreadsheet file Run DRAINS using calculation engine in Design or Analysis modes Data in Data base and GIS programs CAD Programs Export results Re
255. ious and a pervious area coefficient for design and another set of these for analysis For a particular sub catchment the rational method is applied as follows Q Cimp Aimp Cpe Aper Equation 5 9 where Qis the design flowrate in m s Cimp and Coery are impervious and pervious area runoff coefficients Aimp and Aper are the impervious and pervious areas ha and is the rainfall intensity mm h corresponding to the appropriate time of concentration o gt DRAINS Linear ILSAX Linear DRAINS wo Calculated Flowrates m 3 s e ILSAX 0 0 5 1 1 5 2 2 5 3 3 5 4 4 5 Recorded Flowrates m s Figure 5 15 Hewitt Results DRAINS performs a search between 5 minutes and the usually longer times specified for the impervious and pervious areas to find the time that provides the greatest value of Q C I A overcoming the partial area problem whereby the lower part of a catchment produce a higher estimate of a flowrate than the total catchment Rational method times of concentration are specified in exactly the same way as ILSAX model times of entry in the property sheet for sub catchments as described in Section 5 3 2 d The first general method is a plain implementation that has no special fixed features and can be applied outside Australia or within Australia if the user wants to depart from the Australian Rainfall and Runoff 1987 method The second
256. is assumed in the interests of stability of calculations and is likely to conservatively overestimate changes 5 6 7 Tailwater Levels DRAINS calculations require a downstream boundary condition with the levels of the receiving water being specified in advance This can be a level specified by the user in the Outlet Node property sheet or one assumed from conditions at the outlet For steep pipe slopes supercritical flow it will be assumed to be the normal depth and for mild pipe slopes subcritical flow it will be assumed to be the critical depth in the standard and premium hydraulic models Setting an appropriate tailwater level can be difficult The For a pipe system discharging to a free water body such as a lake large stream or the sea the tailwater will be the water level occurring in this body at the time that the storm passing through the drainage system occurs Using DRAINS you must determine the most likely level coinciding with the storm for normal design or analysis and high values such as high tide levels in marine waters for modelling of extreme conditions The DRAINS Utility Soreadsheet includes a procedures for modelling a tailwater level that changes with time during a storm event Where the drainage system catchment is significantly smaller than the catchment of the larger receiving water body it is likely that the rainfalls over the two catchments will differ in intensity and timing The estimation of appropriate events
257. is continuing development process provides benefits from improvements to DRAINS modelling techniques and breadth of coverage DRAINS User Manual 1 1 November 2014 DRAINS is available in versions for 20 50 and unlimited numbers of pipes or channels The ILSAX hydrology or rational method can be chosen Optional ILSAX or rational method procedures storage routing models GIS capabilities and unsteady flow hydraulics in overflow routes are available at extra cost Current prices are available from Bob Stack of Watercom Pty Ltd on 02 6649 8005 or bobstack watercom com au 1 1 2 Modelling Aspects a Hydrology to Estimate Flows The ILSAX hydrological model illustrated in Figure 1 2 is the original model used to simulate the operation of urban stormwater drainage systems in DRAINS It comes from the ILSAX program O Loughlin 1993 described in Section 5 3 2 This model uses time area calculations and Horton infiltration procedures to calculate flow hydrographs from sub catchments The various sub catchment flows are combined and routed through a pipe and channel system Calculations are performed at specified times after the start of each storm using time intervals of one minute or less At each time step a hydraulic grade line analysis is performed throughout the drainage network determining flowrates and water levels Intensity Rainfall Hyetograph Pit and Pipe system F N Flowrate B T n J gt N N
258. is used for the full diagram only Figure 3 35 Print Diagram Dialog Box The process of importing data in DXF format was presented in Section 3 2 2 There are two types of output via DXF file format one of the most common formats used for drawings With the Toowoomba Estate drn file you can export a plan view to scale using the Export DXF File option in the File menu This opens a Save As dialog box and after a file name and location are specified opens the DXF File dialog box shown in Figure 3 36 The resulting file can be opened ina drawing program appearing as shown in Figure 3 37 The background and pipes are supplied on different CAD layers DRAINS User Manual DXF File At Pits Show ei C Nothing Show pipes on f One layer C Separate layers On Pipes Show f Diameter C Length f Nothing Cancel Figure 3 36 DXF File Details Dialog Box 3 23 November 2014 auteCan LT ficowoomba estate cdxf fA File Edit View psen Format Tools Draw Dimension Modify Window Help Sor Caer Fae m at om s SB RRB BBA tecare Be HET ga ji a x m 8 9 oa Sm BAS UND ooa 9 Oa Sm BASINS No selection l z 7 Ow Ge BRIDGES 2 dk 9 ca Sm CHANHELS Crteqerined o al Oe Se CULVERTS laa Oe Gm NODES T io 9 oe 2m ove Tes E iylar Ei f 7a Layer rie E Linetype SyLaper wiin Linetype scab 1 0000 Lingwrcight ByLayper fo Thmckirat 65 0 0000 parle E Pot style ot
259. ished relationships using hydraulic principles allowing for approach flows up to 2 5 m s for on grade pits and depths of ponding of up to 0 6 m for sag pits None of these relationships have been approved by the originating authorities It is up to each user of DRAINS to determine whether they are suitable for their purposes Users can readily modify the relationships The available relationships for New South Wales apply to the pits described in Table 5 13 Table 5 13 New South Wales Pits Pit Type Kerb Inlet Comments Dimensions NSW Roads 1 0m wide x 0 15 1mx0 45m A kerb inlet grate combination and Maritime depressed by 25 mm below Services normal gutter levels er Wel ie SA2 1 83mwidex 0 915mx0 45 As above De ee 0 15 m high m DMR pits DMR 1979 2 745 mwidex 0 915mx0 45 As above O Loughlin 0 15 m high m Darlington and SF 1 Median pit with As above House 1992 cover o SO V Channel None 0 7 x 0 7 m or V shaped pits located in V a Te 0 7 x 1 4 m Channels 1990s SK V Channel None 0 825 x 0 7 mor V shaped pits located in V 0 825 x 1 4m Channels Hornsby 0 9 1 2 1 8 0 9 1 2 1 8 2 4 0 915 m x 0 45 Essentially the same type as Council Pits 2 4 3 0 3 6 3 0 3 6 or 4 2 m m the RTA Pits and 4 2 m wide x 0 15 m wide lintel high NSW Dept of 1 68 1 8 2 4 1 68 1 8 2 4 or 0 9mx0 5m A similar type of pit to the RTA Housing 1987 or 3 0 m lintel 3 0 m wide by pits RM10 Pit 0 15 m high NSW Dept of 0 9mx0 5m A grated pit
260. it These situations are hydraulically different and different forms of relationships are used to describe their inlet capacities Approach Flow Bypass Flow Kerb and Gutter On Grade Pit Figure 5 19 On Grade and Sag Pits On grade pit inlet capacities are defined as a relationship between the inlet flow or capture and the approaching flow This flow is affected by the road cross section properties and its longitudinal slope as well as the characteristics of the inlet Different road and gutter cross sections and roughnesses will create different widths and velocities of flow approaching the pit Since there is no direct theoretical relationship covering all of these factors empirical relationships have been established from laboratory tests and field observations Figure 5 20 shows the relationships for kerb inlets on grade measured in hydraulic model studies published by the N S W Department of Main Roads 1979 As the magnitude of the approach flow increases the percentage of the flow captured will decrease This is represented by the curved line becoming gradually flatter and crossing the dotted lines that indicate various percentages of capture Sag pits can be modelled more easily as the theory of weir and orifice flow can be applied to relate inlet capacities to depths of ponding Experimental investigations have confirmed the following weir equation given in Australian Rainfall and Runoff Institution of Enginee
261. ith RAFTS storage routing calculations c full unsteady flow modelling employed in premium hydraulic model calculations Overflow routes between pits or nodes can be divided into a number of overflow route segments separated by nodes They can also combine at a node as shown below Cat D2 PitO2 Pipe De A path made of two or more segments can have differing cross sections slopes etc In premium hydraulic model calculations DRAINS traces a HGL through these segments defining a backwater curve on mild slopes b Basic and Standard Hydraulic Model Inputs With the standard or obsolete basic hydraulic models clicking on an overflow route opens a two or three page property sheet As shown in Figure 2 25 all that is required on the Basic Data page is a name and an estimated time of travel During calculations any overflow hydrographs will be delayed by this time of travel The information on the second Cross Section Data page which is the same for all hydraulic models is described in Section e ee fe Overflow Route OF 1 Basic Data Overflow Weir Properties Cross Section Data Name PET Travel Time mins Figure 2 25 First Page of the Overflow Route Property Sheet Top Portion c Premium Hydraulic Model Inputs If premium hydraulic model calculations are enabled the first page of the property sheet should have the form shown in Figure 2 26 Rather than specifying a travel time t
262. ith lower rainfall Port Adelaide South Australia Results from models adapted from the Gymea model are shown in Table A 11 and Table A 12 At Manly the 10 year ARI 1 hour rainfall intensity of 68 mm h leads to pervious area runoff coefficients of Cio 0 67 C5 0 64 and C199 0 80 An AMC of 3 is used for comparisons The impervious area coefficients are the same as at Gymea and the comparative results are similar to those at Gymea with the ILSAX models giving higher peak flows and volumes At Port Adelaide the 10 year ARI 1 hour rainfall intensity of 24 5 mm h defines pervious area runoff coefficients of C1 0 10 Cs 0 095 and Cio 0 12 The Soil Type is assumed to be 2 reflecting sandy soils and combined with the lower rainfall intensities runoff can be assumed to be much lower than at Gymea and Manly The ILSAX estimates in Table A 12 are generally below the rational method peaks and volumes Even if the AMC is set at 3 the rational method estimates are still slightly higher although the differences in flows and volumes are small These comparisons are provided as information for designers and reviewers It is beyond the scope of this Guide to argue the merits of the individual models Other Hydrological Models in DRAINS DRAINS can also apply runoff routing or storage routing models emulating the RORB RAFTS and WBNM programs described in Chapter 5 of this manual These can be viewed using the Hydrological Models option
263. iven in the next section Microsoft Vista and Windows 7 impose restrictions that may affect users ability to change the standard data base stored in the Drains dbl file see Section 2 4 2 The user should have permission to modify files inC ProgramData Drains 1 1 4 Support For support contact Watercom Pty Ltd at phone fax 02 6649 8005 or bobstack watercom com au Training workshops are conducted by Dr Geoffrey O Loughlin who can be contacted on phone 02 9570 6119 or 0438 383 841 fax 02 9570 6111 and geoff oloughlin tpg com au They are communicated to DRAINS users by e mail and advertised by mail outs to organisations involved with urban stormwater management DRAINS User Manual 1 4 November 2014 1 1 5 Installation If you are setting up the demonstration version or updating a DRAINS program that is already installed you only need the file DrainsSetup exe which can be downloaded from the website www watercom com au or obtained on CD Click your mouse on the icon for DrainsSetup exe and when prompted enter the password provided by Watercom Pty Ltd or enter DEMO to install the demonstration version Then follow the instructions acknowledging the Conditions of Use For the first installation of DRAINS on a PC that is to be used with a hardware lock you should install from the CD ROM provided when DRAINS is purchased The USB locks that are currently supplied do not require a driver Installations can be made o
264. l QUDM see Section 0 Before using these procedures you must run DRAINS to obtain a set of flows and HGLs as shown in Figure 3 30 DRAINS User Manual 3 19 November 2014 3 Penrith ARR87 Example Standard DRAINS E z File Edit Project View Draw Run Help Dsm S olemalla olv eE of ale Drainage Pit Pit Properties Pond Properties QUDM This is a Baseflow Cat 1 Pit 1 en Inflow Hydrograph f Name Pit 4 Surface Bev m 56 3 Pit Family NSW Dept of Housing RM 10 Pit D Pit Size 1 68 m lintel all slopes Pressure loss coefficient j3 Ku for full pipe flow OF1 he 2Pipe 1 m Pipe 4 Pit has bolt down impermeable lid Cat 5 This pit is Blocking Factor Oto 1 0 0 unblocked New can be designed Use default value of 0 5 OF 5 Existing cannot be designed You specify Outlet Outlet 2 Press F1 for help Figure 3 30 Sample System with Initial Pressure Change Coefficients For example you might set up a system as shown below guessing K factors or setting all factors to the default value of 1 5 You would than run the models and select the method you wish to apply in this case the QUDM Chart procedure as shown in Figure 3 31 3 Penrith ARR87 Example Standard DRAINS File Edit Project View Draw Help j O j g Analyse major storms standard hydraulic model i Worst case minor stom Analyse minor storms standard hydrau
265. l Infiltration Rates of Urban Catchments 28th International Hydrology and Water Resources Symposium Institution of Engineers Australia Wollongong Standards Australia Standards New Zealand 2003 AS NZS 3500 3 2 2003 Plumbing and drainage Part 3 Stormwater drainage Sydney Stephens M L and Kuczera G 1999 Testing the time area urban runoff model at the allotment scale Proceedings of the 8 International Conference on Urban Storm Drainage edited by I B Joliffe and J E Ball Sydney Streeter V L and Wylie E B 1981 Fluid Mechanics 8th Edition McGraw Hill New York Terstriep M L and Stall J B 1969 Urban runoff by road research laboratory method Journal of Hydraulics Division ASCE Vol 95 No HY6 November Terstriep M L and Stall J B 1974 The Illinois Urban Drainage Area Simulator ILLUDAS Bulletin 58 Illinois State Water Survey Urbana Tran L 1998 Operation of Urban Gauging Station and Analysis of Cranebrook Catchment Undergraduate Project Faculty of Engineering University of Technology Sydney U K National Water Council 1981 Design and Analysis of Urban Storm Drainage The Wallingford Procedure 5 volumes London U K Transport and Road Research Laboratory 1976 A Guide for Engineers to the Design of Storm Sewer Systems Road Note 35 2nd Edition 1st Edition 1963 HMSO London U S Department of Transportation Federal Highway Administration 1984 Drainage of Highway Pavements Hydraulic
266. l Intensity mm hour 12 Hour Rainfall Intensity mm hour 72 Hour Rainfall Intensity mm hour Rainfall Block Duration mins 1 Storm Duration mins 120 Note The Storm Duration does not affect rainfall values It merely serves to cut off the low rainfall values at the beginning and end of the synthetic storm Preapitaton Intensity Pattern f 2 3 1 3 Distribution Figure 2 72 Dialog Box for Setting Up Synthetic Storms Synthetic storm patterns consist of a number of nested storms with the average intensity for any duration equalling the intensity specified by the I F D relationship for that duration Originally Known as the Chicago storm patterns these relationships have been used in the United States for some time and are also applied in the UK and Hong Kong d Adding Storms by Hand or by Spreadsheet Transfer It is also possible to set up non standard patterns by clicking the Add a New Storm button in the Rainfall Data property sheet to open the box shown in Figure 2 74 DRAINS User Manual 2 46 November 2014 Rainfall Data Storm i of E Name 5 pear AAI synthetic storm Antecedent moisture condition 1 to 4 3 Annual Recurence Interval years p Storm duration mins 120 Rainfall specified in 1 minute intervals Time minz Intensity mm h DD to1 0 a 13 5462 e Paste Intensity mm h Comments 60 20 Time mins Add one ARRS storm OF Add multiple ARAG
267. l Led 705 3 0 0 2 301 465 Pit B 7 OnGrade Qld DMR Gully Pit both 0 25 2 grade S Lintel Leo 704 5 0 0 2 329 035 N 3 Node 704 3 0 348 224 3 153 244 N 4 Node 703 5 Oo 373 740 71 352 249 N 5 Node 702 5 0 428 021 103 363 250 N 7 Node 701 4 0 524 055 120 993 275 Outlet Node 699 5 o 627 512 173 417 280 Pit C 1 Sag Qld DMR Gully Pit both 0 25 2 grade S Lintel 5 4 5 706 8 0 2 Oo 0 2 212 647 7 63 Pit C 2 OnGrade Qld DMR Gully Pit both 0 25 2 grade S5 Lintel 0 5 705 8 0 0 2 227 745 N 1 Node 704 8 m 348 224 87 778 252 HW 2 Headwall 0 5 704 2 o 348 224 12 620 269 No Node 703 4 0 352 399 137 694 305 SUB CATCHMENT DETAILS Name Pit or Total Paved Grass Supp Paved Grass Supp Paved Grass Supp Paved Grass Supp Paved Grass Supp Lag Time Node Area Area Area Area Time Time Time Length Length Length Slope 4 Slope Slope Rough Roug ihaj imin imin min im im im im Cat B 1 Pit B 1 0 7560 35 0 60 0 5 0 T 10 1 Cat B 2 Pit B 2 0 1320 65 0 15 0 0 0 3 4 Oo Cat B 3 Pit B 3 0 5400 40 0 55 0 5 0 7 10 0 Cat B 4 Pit B 4 0 1040 65 0 15 0 0 0 3 4 Oo Cat B S Pit B 5 0 6020 35 0 60 0 5 0 7 11 m Cat B 6 Pit B 6 0 1680 65 0 15 0 0 0 4 5 o Cat B Pit B 7 0 3810 40 0 55 0 5 0 7 11 I Cat 3 N 3 0 1600 0 0 100 0 0 0 m 5 o m Cat 4 N 4 3 7550 30 0 70 0 0 0 13 20 o o Cat SN S5 2 0050 10 0 90 0 0 0 18 25 o o Cat 6 Cul 6 1 0700 0 0 100 0 0 0 0 20 o o Cat 7 Basin 6 1 8700 5 0 90 0 0 0 15 25 oO o Cat 9 Bridge 9 4 1500 0 0 90 0 0 0 0 30 o 0 Car Ci Dir
268. l describes methods for dealing with these If tailwater levels are not high overflow routes can model these accurately DRAINS User Manual A 27 November 2014 File Edit Properties Total Inflow Volume 9610 6 cu m Total Outflow Volume 9065 5 cu m O utf OW Flow cu m s 60 120 Time mins Figure A 30 Routed Inflow and Outflow Hydrographs for a Detention Basin e Modelling of sumps or infiltration basins It is possible to model basins without outlets where water is disposed of by infiltration DRAINS models the entry of inflow hydrographs and the slow draining of the basin monitoring storage levels and enabling the storage volumes required to be defined One matter that frequently arises is how to model a requirement that post development flows must not exceed pre development flows This can be difficult because many ARIs and storm durations must be considered When on site detention systems were first introduced most authorities required only that 100 year ARI flowrates to meet this requirement with some applying a more rigorous requirement such as ensuring that 100 year ARI post development flows to be no greater than 10 year ARI pre development flows This was sometimes justified on the basis that the downstream pipe capacity was limited to say 10 year ARI but was also a means of limiting flows at ARIs lower than 100 years to pre development levels It has now become common to limit post developme
269. l lel i Sm Home Insert Page Layout Formulas Data Review View Add Ins Acrobat 9 o ep ss S57 M f A B c D E F G H i j K L M N o p Q x ees us 1 DRAINS results prepared 27 October 2012 from Version 2012 12 E 2 3 PIT NODE DETAILS Version 8 4 Name Max HGL Max Pond Max Surfa Max Pond Min Overflow Constraint 5 HGL Flow Arriv Volume Freeboarc cu m s 6 cu m s cu m m Results for Pits 7 Pita 21 38 0 051 0 72 0 013 Inlet Capacity and Nodes f 8 Pit5 20 93 0 004 0 77 0 None 9 Outletl 20 17 0 10 Pit1 21 73 0 007 0 77 0 None 11 Pit 2 21 52 22 36 0 015 ES 0 78 0 Inlet Capacity 12 Pit 3 21 21 0 005 0 79 0 None E 13 14 SUB CATCHMENT DETAILS 15 Name Max Paved Grassed Paved Grassed Supp Due to Storm 16 FlowQ MaxQ MaxQ Tc Tc Tc 17 cu m s cu m s cu m s min min min 18 Cat4 0 051 0 05 0 001 9 15 1 AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 19 Cat5 0 004 0 004 0 2 3 0 AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 S u b Catch ment 20 Cat1 0 007 0 007 0 8 13 1 AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 Resu Its 21 Cat2 0 015 0 015 0 9 15 1 AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 22 Cat 3 0 005 0 005 0 3 4 0 AR amp R 2 year 25 minutes storm average 40 2 mm h Zone 1 23 24 25 Outflow Volumes for Total Catchment 0 45 impervious 0 30 pervious 0 75 total ha 26 Storm Total Rain Total Runcimperviot Pervious Runoff Ru noff 27 cu m cu m Run cu m Run cu m
270. l types which follow the classification used by Terstriep and Stall 1974 based on the system developed by the U S Department of Agriculture and described in references such as Chow 1964 and U S Natural Resources Conservation Service 2007 These are used in North American procedures such as Technical Release 55 of the U S Soil Conservation Service 1975 The four main soil classifications designated A B C and D corresponding to 1 2 3 and 4 in the ILSAX type model are described as 1 or A low runoff potential high infiltration rates consists of sand and gravel 2 or B moderate infiltration rates and moderately well drained 3 or C slow infiltration rates may have layers that impede downward movement of water 4 or D high runoff potential very slow infiltration rates consists of clays with a permanent high water table and a high swelling potential These soil types are used in conjunction with antecedent moisture conditions AMCs that define the points on the infiltration curves at which calculations commence This is specified not by an initial infiltration rate in mm h but by an antecedent depth of moisture corresponding to the area under the curve to the left of the starting point On each curve in the above figure four starting points numbered 1 2 3 and 4 are shown representing possible AMCs AMCs can be estimated from Table 5 5 Both soil types and AMCs can be interpolated between the levels of
271. l with time area routing The rational method only calculates peak flowrates The ERM applies a loss model based on the rational method with time area routing These models are adaptable to many situations but do not perform continuous simulation The storage routing models that emulate the RORB RAFTS and WBNM models commonly used in Australia are also event models designed to produce hydrographs for flood estimation but not capable of modelling long periods of runoff under wet and dry conditions 5 3 2 The ILSAX Hydrological Model a General Description This model relates to an urban or semi urban catchment subdivided into sub catchments linked to a drainage system of pipe and channel sections as shown in Figure 5 4 Sub catchments are divided into three surface types paved supplementary and grassed Runoff hydrographs generated from inputted DRAINS User Manual 5 3 November 2014 rainfall patterns are used to model system behaviour and to perform design tasks The model works to a fixed time scale beginning at the start of a storm performing calculations at specified time steps Rainfall n Rainfall Hyetograph Losses Time Rainfall LOS S Defines rainfall excess equivalent to runoff at MODEL the point where it begins Time Rainfall i Excess i Time RO U TI N G Combines rainfall excess from different areas and M O D E L allows for delaying effects of time of travel and storage Runoff i e Time Figure 5
272. ld level TH m AHD usually the invert at the upstream end of the culvert and the height of the culvert H m If HW TH lt 1 35 H the flowrate for Inlet Control is Q Nc 1 70 HW TH B Equation 5 38 inlet control submerged inlet Boyd 1986 If HW TH 2 1 35 Height of Culvert Q Nc 2 20 HW TH H B Equation 5 39 inlet control submerged inlet Boyd 1986 The flowrate for Outlet Control is Q Nc H B HW TW 2g ke kp Factor DE Equation 5 40 outlet control full pipe flow As for circular pipes the outflow rate Q m s corresponding to level HW is the lesser of the calculated Q and Q values B is its breadth or width of the conduit m and the other factors are as described above In the calculations concerning tailwater the critical depth is determined as Q 0 333 de e Equation 5 41 In the equations for finding the friction factor diameter D is taken to be 4 times the hydraulic radius m equal to 7 H B Area Wetted Perimeter H Equation 5 42 2 H B In most cases inlet control will govern with the greatest restriction on flow capacity occurring at the culvert entrance However in some cases outlet contro will apply with the cause being high tailwater levels or friction in relatively long and flat culverts DRAINS User Manual 5 40 November 2014 High level outlets such as weirs and slots are usua
273. le Edit Project View Draw Run Help Djela S olaaa File Edit Properties 701 4 701 2 Elevation m 0 oD N esas an oOo o N Distance 3 Crk 8 Maximum Water Levels o File Edit Properties ag aaa a ie Critical Depth a ca 0 0 577 1 51 700 6 5 E isz A 5 49 oa A 702 33 5820A Qui sah 701 ony 7 N 0 93 0 273 701 08 2 92 0 249 700 90 Q 371 3 7 ee ok 371 699 6 698 gt Y aai 5 0 10 20 30 40 50 60 Distance m from U S end i 0 508 700 Elevation m 699 8 Results of Premium Hydraulic Analysis Figure A 32 Open Channel Model Results Reviewers need to be satisfied that the analysis has been carried out correctly and will probably expect a conservative estimate Generally the more uncertain the conditions and the less experienced the modeller or designer the more conservative the results should be Using the ILSAX model DRAINS has been applied in detailed models of existing drainage systems of 2500 pits extending over 3 km This is reasonable as long as all parts of the system are modelled in detail However a problem occurs when a point of interest such as a re development site is located well downstream in a catchment The drainage system near the site can be modelled in detail but the difficulty lies in determining to what accuracy the upper part of the catchment drainage system should be modelled If all of the
274. lengths to performing routing calculations that will usually reduce flowrates A more detailed modelling of sag pit storages will add to this effect Results for the Orange examples are shown in Figure 1 46 It is possible to plot long sections for overflow routes determining flow characteristics along these An animation Figure 1 47 of the changing HGL levels in a selected part of the system can also be run from premium hydraulic model results DRAINS User Manual 1 27 November 2014 3 Orange2 premium DRAINS File Edit Project View Draw Run Help a OF 4 Maximum Water Levels A 5 L z pie P 8 A alaj H vje Hi A e w O als File Edit Properties s a a O Critical Depth AR amp A 100 year 25 minutes storm average 101 mm v E 0 06 0 064 C 8008 3 ES e mar i gt Ww 0 2 4 6 8 10 12 14 16 18 20 22 24 Distance m from U S end 0 000 f i 3 Pit 3 HGL AR amp R 100 year 25 minutes storm average 101 mm h Zone 2 Lo E _ 3 Pipe 3 Hydrograph AR amp R 100 year 25 minutes storm average 101 mm h Zone 2 File Edit Properties File Edit Properties 0 1 rr 1 1 0 09 0 08 v 0 07 E 0 06 a 0 05 aI Aod ay A G A A A Outlet Obvert Level 2 5 21 3 0 03 21 2 z 0 02 21 1 TE 0 01 21 m a E 0 0 20 40 60 80 100 120 0 20 40 60 80 Time mins Time mins For Help press F1 a SS EEE Se Figure 1 46 Results from Premium Hydraulic Model for a Major S
275. les folder among the files supplied with DRAINS which are also obtainable from www watercom com au can be used to explore the operation of DRAINS The manual covers the operation of Version 2014 07 of DRAINS An appendix provides information on the DRAINS Viewer a free program that can be used to review DRAINS models and result files DRAINS uses hydrological and hydraulic methods developed by generations of engineers If you have formal training in water engineering and experience in using models and encountering practical problems you should find the program easy to use and to interpret If you are a beginner in the fields of hydrology hydraulics or stormwater system design or are out of practice this manual and the Help system will assist you towards understanding the program s operations and outputs DRAINS can apply four types of alternative hydrological models and two hydraulic modelling procedures This manual can be used as a learning guide for DRAINS or as a reference manual that you can dip into There is an index at the end and you can use PDF search functions to find topics in the electronic version Most displays of screens are in Microsoft Windows 7 style these displays may appear different in XP or classic style but the contents are the same Chapter 1 describes what DRAINS is and does and how it can be installed To get you started it provides a simple example that takes you through the steps of entering data runni
276. lic model Analyse major storms premium hydraulic model 0 26 62 01 Analyse minor storms premium hydraulic model 6073 d Design Revise Pit Loss Coefficients gt Using QUDM Charts if 0 254 Quantities b Using Mills Equation Figure 3 31 Applying the QUDM Charts Procedure The following messages will appear ah The current values of pit loss coefficients for full pipe flow will be lost Ie DRAINS will change them based on the QUDM Volume 2 charts using surface inflow flows in pipes incoming pipe angles pipe sizes and levels Pit losses for part full flow will not change for pits using either the QUDM method or a specified loss in mm However they will change for pits where the part full loss is based on the coefficient for full pipe flow Refer to the three radio buttons in the pit property sheet Do you want to proceed DRAINS User Manual 3 20 November 2014 DRAINS ee Pit loss coefficients have been changed based on current maximum flows and levels You will often get different coefficients if you use major storm or minor storm results This is due mainly to different relative flows in pipes and from the surface into the pit You should check the loss coefficients generated by DRAINS There is a summary of changes on the Clipboard You can paste this into Excel to review it A B D E 1 Pit Initial K Revised K Chart Ratios 2 PitS 0 83 0 63 A1 9 Du Do 1 00 Qg Qo 0 05 S D
277. lifornia Institution of Engineers Australia 1987 Australian Rainfall and Runoff a Guide to Design Flood Estimation 2 volumes edited by D H Pilgrim and R P Canterford Canberra loose leaf version produced in 1997 Izzard C F 1946 Hydraulics of Runoff from Developed Surfaces U S National Research Council Highway Research Board Proceedings Vol 26 p 129 150 with discussion Neville Jones amp Associates Pty Ltd and Australian Water Engineering 1992 Queensland Urban Drainage Manual 2 volumes prepared for the Queensland Water Resources Commission the Local Government Engineers Association of Queensland and Brisbane City Council Brisbane Laurenson E M and Mein R G 1990 RORB Version 4 Runoff Routing Program User Manual Monash University Department of Civil Engineering with Association for Computer Aided Design ACADS and Montech Pty Ltd Melbourne Mays L W 2001 editor Stormwater Collection Systems Design Handbook McGraw Hill New York Mein R G and O Loughlin G G 1985 Application of ILLUDAS SA to Gauged Urban Catchments E Aust Hydrology and Water Resources Symposium Sydney Mills S J and O Loughlin G G 1982 98 Workshop on Piped Urban Drainage Systems Swinburne Institute of Technology and University of Technology Sydney first version 1982 latest 1998 New South Wales Department of Housing 1987 Road Manual Sydney New South Wales Department of Main Roads 1979 Model Analysis to
278. lly governed by the weir equation 0 C wehy Equation 5 6 where Qais the outflow rate m s C is a weir coefficient depending on the weir shape roughness and length of the weir crest in the direction of flow w is the width of the weir m at right angles to the flow direction and hw is the depth of water in the basin above the weir sill or crest Laurenson and Mein 1990 provide the weir coefficients shown in Figure 5 31 Further information can be obtained in the US Federal Highway Administration HDS 5 manual Normann et al 2005 Ogee Broad crested sloping approach Broad crested vertical upstream face Sharp crested vertical upstream face Figure 5 31 Weir Coefficients 5 8 3 On Site Stormwater Detention DRAINS is set up to model on site stormwater detention OSD storages of the type shown in Figure 5 32 including high early discharge HED systems as shown in Figure 5 33 These can provide a considerable reduction of the storage needed to limit outflows to a prescribed limit Speed Hump Storage on Driveway acts as a weir Orifice Plate Above Ground Storage Underground Tank Screen oo Figure 5 32 On Site Detention OSD Storages DRAINS User Manual 5 41 November 2014 Weir HED Pit Main Storage Outlet Inlet Pipe Pipe HED Pit Components th alt State 1 The HED Pit Fills State 2 The Larger Storage Fills AG aw State 3 Both Storages are Full and
279. lows pass through pits a pit pressure change relationship is applied using the ku factor shown in Figure 4 4 which is specified by the user in the pit s property sheet Grate Flow a a e Figure 4 4 Pit Pressure Change Relationships The change from part full to full pipe flow often results in a large increase in the pit pressure change This raises the HGL level and causes a rise of HGL that moves upwards through the system A jump in pressure at a pit may actually be due to filling of another pit somewhere downstream A similar drop in HGL and pressure may occur when a full flowing pipe changes to part full flow While pit pressure changes have been studied for full pipe flows there is little information available about pit pressure changes and energy losses in pits with part full flow Currently DRAINS assumes that k coefficients are constant and the same for both full and part full flows This is likely to be conservative overestimating changes for part full flows It also provides more stable results lf a sag or on grade pit is defined as being sealed using the check box labelled Pit has bolt down lid in the Pit property sheet the HGL can rise above the surface without any upwelling occurring DRAINS calculates upwelling flows using hydraulic analyses With the basic hydraulic model no outlet restrictions are placed on upwelling flows unless the pit has a bolt down lid With the standard a
280. ls and run the model in Analysis mode or make the pipe inverts fixed Long Section Drawing P Al BS Al BS m r e i a Tran Irm Lar Lor 4 JE 5 KR TE i HE gg 88 r m r m m mmr _ g wj iP r ize 5 j g L r P r r r oe HEE HEE 3g gy HH ag r r r m P mm 5 w a H 5 C Save as DXF Print Customise Close Help Figure 4 6 Display showing a Drop Pit and Intermediate Levels DRAINS can automatically design to avoid fixed services where possible using service location information entered in the Survey Data property sheet and a minimum design clearance to services set in the Options property sheet called from the Project menu One such service is shown in Figure 4 6 and also in Figure 4 7 lf a Design run is made with the positions of some of the pipes fixed the results must be carefully checked especially if these are located in the middle of lines In some complex Design cases pipes entering pits might be lower than a fixed pipe flowing out The fallback in this case is to run in Analysis mode with pits and pipes made existing and to vary pipe sizes and invert levels individually to achieve a satisfactory design Where multiple storm patterns are specified the program repeats the downwards pass for each storm and selects the pipe diameters and invert levels that convey the most critical flows DRAINS User Manual 4 9 November 2014 Pipe B 5 Maximum Flow and
281. mation can be changed later If you open and close an existing DRAINS model the hydrological model and rainfall from that model will remain To start afresh you need to exit from DRAINS and start up again In this case the databases for the hydrological model and rainfall data will be empty while those for pipes pits and overflow routes will be taken from the file Drains db1 located in the C ProgramData Drains From the Project menu at the top of the screen you can select Hydrological Models The window in Figure 1 5 appears showing a dialog that is used to establish hydrological models Not all of the options shown may be available with your hardware lock x Default Model for Design and Analysis Runs Cancel Orange Soils Note Ifyou wantta edit a model other Delete Default Model than the default model make tthe default model temporarily Edit Default Model In addition to the Ilsax model you may use Add ILSA Model one ofthe following models in this project If yOu wish YOU mE select one Add Rational Method Model Add Extended Rational Model RORB RAFTS Add Storage Routing Model o WBN Help Figure 1 5 The Hydrological Model Specification Dialog Box DRAINS User Manual 1 6 November 2014 ILSAX hydrology is used in this example Clicking the Add ILSAX Model button opens the property sheet shown in Figure 1 6 in which the characteristics of the hydrological model can be entered ILSAX T
282. ment is shown in Figure 5 7 Information on surface types is arranged in three columns The length of these varies according to the level of detail selected in the Use box For many applications fixed times can be entered However it is also possible to calculate a time by the steady state kinematic wave equation for overland flows Ragan and Duru 1972 L A e 0 4 0 3 l S where time toveriang IS in minutes flow path length L is in m rainfall intensity is in mm h and slope S is in m m toveriand 6 94 Equation 5 3 The surface roughness n is similar to the coefficient n in Manning s Formula for open channel flows but is of a different magnitude It typically takes the values set out in Table 5 3 Values for lawns and grassed surfaces show considerable variation depending on the depth of flow relative to the height of grass blades Values from 0 05 to 1 0 have been obtained by various researchers as described by Engman 1986 In DRAINS intensity is taken as the mean intensity of the rainfall pattern supplied This should be satisfactory for design rainfall bursts such as those supplied in Australian Rainfall and Runoff 1987 but may be erroneous for some more variable or patchy patterns that occur naturally DRAINS User Manual 5 7 November 2014 For paved areas it is also possible to calculate a gutter flow time using a an equation for flows in street gutters or channels U S Federal Highway Administration
283. ments are presented in Table 1 2 After entering values for Catchment Cat 1 enter parameters for the four other sub catchments The displayed names of all should change eS Sub catchment name Cat 1 Sub catchment area hal 0 125 Use Hydrological Model abbreviated data 0 more detailed data f You specify Paved Supplementa Grassed Percentage of area 74 Zo z Bf E 13 E Time of concentration mine Lag time minutes j Cancel Customise Storms Help Figure 1 23 The Sub Catchment Data Property Sheet Table 1 2 Sub Catchment Data for Orange Example Pit or Grassed Node i Time Pipe data is entered by right clicking on pipes to open their property sheets You need to click on the object and not on its name as the latter will open the dialog box illustrated later in Figure 3 19 that defines the information shown in the Main Window Figure 1 24 shows the sheet for the first pipe It is not necessary to specify invert levels or slopes because DRAINS will calculate these during the design You must however specify the pipe name length and type selecting the type from a list box If you have inserted a background pipe lengths can be automatically scaled after the first length is entered You can also take the lengths of the remaining pipes from Table 1 3 When you close the property sheet you will find that the pipe name is prefixed with indicating that the data are still incomplete
284. model with on site stormwater detention Press FI for help ae al Figure 2 58 Two Drainage Systems Set Up in DRAINS for Comparison 2 4 Data Bases 2 4 1 General By storing data about inputs and common components in five data bases that are easily accessible from drop down list boxes DRAINS makes it easy to select and alter hydrological models rainfall patterns pipe types pit types and overflow route cross sections By referring to standardised types the amount of data that has to be entered into files is greatly reduced The role of data bases is particularly important in the DRAINS pipe design procedure Pipes and pits are both organised into types or families of different sizes from which the program can select Data bases can be set up element by element using the editing procedures described in the following sections Hydrological model and rainfall pattern data bases can be stored in template files and retrieved as described in the next section Pipe pit and overflow route data bases can be imported directly into DRAINS using the Default Data Base option in the Project menu for a new project and the Import gt DRAINS Database DB1 File in the File menu for existing DRAINS files 2 4 2 Standardised Data Bases When you start DRAINS it loads the standardised data base file Drains db1 located on the C ProgramData Drains folder This contains information on pipe pit and overflow route
285. moet Expansion coetticient Help Save and Clase Note single representative cross section will be used in the Upstream IL m standard and premium hydraulic modele It will be adjusted up or down to match the Upstream and Downstream ILe specified Contraction coefficient oOo Mm om A tw hI a e Long Section Data Downstream IL rm Figure 2 44 The Irregular Channel Property Sheet Left Right Reference Bank Bank Station X Y coordinate Left Right Overbank Main Overbank Area Channel Area Y Datum X Figure 2 45 Coordinate System for Irregular Channel Cross Section looking downstream c Standard and Premium Hydraulic Model Calculations The same inputs as those shown in Figure 2 44 are required with the additional information specified at the bottom of the property sheet The additional inputs are the invert levels at the upstream and downstream ends of the reach and the number of the cross section to be considered as representative of the channel reach The two hydraulic calculation options use entirely different procedures The basic method uses methods akin to the steady flow modelling carried out by the well known HEC RAS program Hydrologic Engineering Center US Army Corps of Engineers 1997 in which cross sections are required at each end of an irregular channel DRAINS User Manual 2 30 November 2014 Critical Depth Elevation m Distance m Critical Depth Elevatio
286. must be opened Information is exchanged via the Windows Clipboard by selecting the copy and paste options in the Edit menu After selecting Copy Data to Spreadsheet in DRAINS as shown in Figure 3 42 transfer to Excel and select Paste from its Edit menu DRAINS User Manual 3 25 November 2014 BricsCAD Platinum NOT FOR RESALE License Toowoomba Line B with Major Storm Results dxf gt File Edit View Insert Settings Tools Draw Model Dimension Modify Parametric Mechanical Sheet Metal Window Help Surfaces Grading Alignments Roads Pipes General ARD Express ARDHEC RAS S x EL LPEP LeL a s SHARA magi CRABS 4 OHsA x ear HORH O i m al e aO m Z 9 OaM v BF C Bylayer M ByLayer M Byways SEM FIA Al SC EGR XU KXO 2 SF OBB CSE BPE BaArvew Ks ABH BO AEROS EO BA FAA K SG QKYAE S a B h F c X p a 4 i te Alb a V7 She e Sls GBORN OA L7 156L s HSL pads 1197L s oo B75m 375mm 675mm oo jam M i 2 Dotum EL 70D a g 0 wW wu jan n fe W fo J iD jo t in oo ipa m uu p 4 mit Q mh fy gq eu in ig h S I Sie 6 ESE 4 5 S se 8 a as ISR Ie in in E 8 wz f a a A 26 B 4 E 6 g Fs i a7 a i Hy o mw lu fe o jwr fu n TE 5 RSE ngaa SE R Z d oie 8 pig fa sigl Sh a Soir RIS m RR BIRR PR M Ko o oh gt b o jo f f fl TEE 5 ET oe a A Ld D Oo E a Zoom In Out All Center Dynamic Extents Left Previous Right Scale Window lt Scale
287. n m Distance m from U S end Figure 2 46 Irregular Channel Cross Sections and Longitudinal Profiles Like HEC RAS DRAINS allows cross sections roughnesses and bed slopes to vary along a channel though it is not possible to change the flowrate along a channel This can be done by specifying two or more irregular channels in series The unsteady calculations assume that each open channel has a constant cross section and slope This will suit lined channels well but for natural channels it may be necessary to define several sections of channel to allow for changes of cross section 2 3 12 Multi Channels The prismatic and irregular channel types do not adequately cover the situation where two or more channels with different characteristics connect the same two points This is handled in the basic hydraulic calculations by multi channels that use the property sheet shown in Figure 2 47 to call up the boxes for prismatic or irregular channels or a box for circular channels The data required is similar to that for other open channels Conduit lengths roughnesses slopes and even starting and ending levels can vary DRAINS distributes flows between the different conduits At present DRAINS does not report on the separate flowrates Situations requiring multi channels occur where inadequate open drainage systems are amplified by building a parallel channel or pipe and where grassed floodway channels have a piped underdrain DRAINS Use
288. n any number of PCs Running DRAINS requires that the moveable hardware lock or dongle be connected to the PC s USB or printer ports Locks are programmed to model certain sizes of drainage network up to 20 50 or unlimited links to implement additional rational method ILSAX and storage routing model calculations to import and export data from GIS files and to undertake full premium hydraulic calculations DRAINS can be uninstalled in the usual way for Windows programs The version number of the DRAINS program being used can be found in the About DRAINS Option in the Help menu The License Details item provides information on the capabilities of the attached hardware lock The DRAINS Viewer installs in the same way as the demonstration version of DRAINS No password is required 1 1 6 Starting Up Once installed DRAINS can be opened by e using the Start menu selecting Programs and choosing DRAINS e clicking on a DRAINS shortcut if one is created on your desktop This may be necessary with some server systems or e clicking on Drains exe in the C Program Files Drains Program folder When opened the Main Window of DRAINS appears as shown in Figure 1 4 You can define a drainage system graphically on this blank screen by drawing components such as pits and pipes using the facilities in the menus and toolbar located at the top File Edit Project View Draw Run Help osle S olmal oliu eae o ale To operate DRAINS you
289. n pit and pipe names used The procedure does not work with DRAINS rational method calculations The following instructions relate to 12d Version 7 For more current information contact 12d directly at http www 12d com aus service_and_support technical_ support contact_your_local_ support australia Assuming that you have set up a drainage system in 12d defining pits pipes sub cattchments and overflow routes the steps involved in the transfer process are a While 12d is open start up a DRAINS model with the required hydrology rainfall pipe pit and overflow route data bases Open the pit data base in the DRAINS Project menu and then close this clicking OK When asked if you wish to save the altered data base reply Yes This ensures that the required data base is stored in a file that 12d can access b Next in 12d open the dialog box selected from the menus Design Drainage Sewer More Drains to drainage 4d drains This appears as shown in Figure 3 14 Er _ drainage 4c IOJ Xx Drains database file fection Data txt CJ Drainage 4d ldrainage 4d Pit Families NSW RTA Pits Y Pipe type Concrete Pipe u x Overflow Route Shapes 8m wide road 7 Pit group separator fat 12d pit groups INSW RTA Pits x Drains database in 12d working folder Read Drains database Create drainage 4d Finish Figure 3 14 DRAINS Transfer Dialog Box Specifications in 12d Check the databases making sure t
290. nX nXP gt _e g ai Rd Ready 97 3536 91 8415 0 0000 STANDARD STANDARD 2D Drafting SNAP GRID ORTHO POLAR ESNAP STRACK LWT TILE DUCS DYN QUAD w Figure 3 41 The Exported Longitudinal Section with Hydraulic Grade Line The information shown in Figure 3 43 appears Almost all the information entered for components is presented organised by type of component PIPE NODE SUB CATCHMENT etc This worksheet can be given a name such as Data by double clicking on the tag at the bottom of the sheet and writing in the name in the space that is highlighted X Y coordinates are given for pits and nodes referring to their positions in the Main Window If a base drawing is imported from a CAD or GIS file the coordinate system will be consistent with this 3 Toowoomba Estate DRAINS 2 File Project View Draw Run Help B here Jels a ale Wors Copy Data to Spreadsheet Copy Results to Spreadsheet Copy Check HGL to Spreadsheet Paste Data from Spreadsheet Find a ie gt 0 078 0 267 Find 0 374 706 57 0 196 706 70 on ne E R06 050 15 o 30 0124 Pegasus EE 0315 amp y 0 367 MEET v9 Gr g 704 0 i 705 59 704 70 70 Y 1 95 0 249 0 474 0 099 9 703 67 z AARS 042 sn rrine a aos reel lala 0 184 244 ogag i See 0 599 704 65 aie 705 91 y 092 0 583 PEYI ain S 702 74 0 351 4 w p Figure 3 42 Copying Spreadsheet Data to the Clipboard after a Design Run DRAINS User Manual 3 26
291. nd all overflow paths must have downwards slopes In this model overflow routes are modelled in the same way as open channels and backwater effects can apply DRAINS User Manual 4 6 November 2014 g Detention Basins The calculations for detention basins in DRAINS can be complex because the elevation discharge relationship will change if the downstream tailwater level submerges the outlet This can happen at many time steps during a DRAINS run so that the relationship changes By contrast ILSAX and most other models for trunk drainage systems assume that the relationship is fixed Thus DRAINS can model interconnected basins Flows through culverts and bridges are modelled using the same equations as outflows from detention basins since they obstruct flows and can have low level outlets the channel under the roadway and high level outlets overflows over the road They do not have any associated storage Where this may be significant the situation can be modelled as a detention basin DRAINS returns similar information in the Main Window for detention basins culverts and bridges the upstream and downstream water levels 4 2 8 Calibration This process of fitting a hydrological computer model to observed or recorded information is done by varying the model parameters Some calibrations made using DRAINS and similar models are presented in Sections 5 3 3 and 5 3 5 In DRAINS the main factors that can be varied are e the soil type d
292. nd completing the dialog box shown in Figure 2 72 to produce the pattern shown in Figure 2 73 The four intensities must be obtained from the local I F D data A block duration of 1 minute is recommended to allow exact matching of 5 6 7 8 etc minute intensities in the I F D data The volume of the hydrograph will increase for longer storm durations The storm duration selected should be considerably longer than the time of concentration of the catchment The 2 3 1 3 option pushes the peak of the rainfall pattern to the right so that its peak occurs at two thirds of the specified storm duration Further information on this can be obtained in the San Diego County Hydrological Manual available on the internet This is claimed to be more conservative for detention basin design DRAINS User Manual 2 45 November 2014 Rainfall Data Chor 11 B cf a Mame ARS F ear 3 hours storm average 9 4 mmh one 6 Antecedent moisture condition 1 to 4 3 Annual Recurrence Interval pears z Storm duration mina 180 Rainfall specited in 15 minute intervals Time minz Intensity mmh D0 to 150 A 6 89 amp Paste Comments 40 80 80 100 120 140 180 180 Intensity mm h Time mins Add one SARE storm Add Synthetic Storm OF Add multiple ARR storms Add a New Storm Help Figure 2 71 Added Multiple Storms Synthetic Storm Da tmm ARI years ps 6 Minute Rainfall Intensity mm hour 1 Hour Rainfal
293. nd developments located within established urban areas is more complex that greenfields design There are many more constraints such as e the presence of existing infrastructure such as water pipes and electricity cables e the need to connect into an existing drainage system which may create problems due to low availability of head and limited downstream capacity e the presence of multiple land owners e difficulties of construction due to limited space and conflicts with traffic and other activities in the area It is unlikely that designs of pipe systems can be carried out automatically as in a new subdivision Analysis capabilities are required when exploring solutions Users will probably have to vary some DRAINS User Manual 4 13 November 2014 features by hand to develop a trial and error solution Fortunately DRAINS can be easily edited and re runs can be carried out rapidly While DRAINS allows users to mix pipes that have fixed inverts with pipes with positions that can be varied it may not be able to develop with a suitable design in some cases When dealing with a complex situation a suitable strategy would be to see whether DRAINS can come up with a satisfactory design first and then make modifications by hand to cope with problems such as conflicting services and the inability of a pipe system to match the inverts of the downstream pipe to which it must connect while carrying the required design flows DRAINS can
294. nd premium hydraulic models a hydraulic loss is assumed to occur when water upwells This is based on the sag pit depth inflow relationship for the pit type and size being used e Tailwater Levels At system outlets DRAINS sets a tailwater level depending on the entries in the Outlet property sheet If a free outfall is specified it determines the higher of the normal and critical depths for the current flowrate If a higher tailwater level is specified in the property sheet for the particular storm being analysed this level becomes the starting point for an upwards projection in the obsolete basic hydraulic model and a boundary condition in the current unsteady models Where a drop pit is so deep that the pit water surface is below the invert of the upstream pipe the starting level for upstream HGL projections will be set in the same way as for a free outlet It will be the higher of the normal and critical depths in the upstream pipe In effect the calculations start again at this pit f Surface Overflows Overflows follow the defined overland flow path to a destination with flows being lagged by the specified time delay which must be at least one calculation time step Although a slope and cross section must be specified for flow paths the standard hydraulic method calculations allow a flow to go from one pit or node to another at a higher surface level despite warnings that are displayed by DRAINS The premium model is stricter a
295. nd premium models are faster than those for calculations with the older basic model The basic model should only be used for checking older models using the methods that applied when such models were developed 4 3 5 Asset Management Once developed and used to prepare construction plans and specifications DRAINS models should be retained by the authority that maintains the system Besides being a record of the system with its own readily accessible database the DRAINS model is a working model of the system which can be altered to reflect any changes It can form part of the authority s asset management system especially when it is integrated with drainage system data base and a geographic information system GIS When the drainage system is constructed it is likely that some details will have been changed during construction The model should be updated to reflect the work as executed information It will then require further modification as whenever e additional drainage systems are connected e rezonings and re developments create more impervious areas and increase runoff volumes and rates possible flow diversions occur within the catchment and between it and other catchments e compensatory detention storages are provided e additional information and experience about the drainage system accumulates DRAINS User Manual 4 17 November 2014 e design rainfalls are revised and climatic change effects occur e the system dete
296. nd the location of other services along these routes To transfer MapInfo data to DRAINS you need to edit the available MapInfo data into pairs of MID and MIF files in the format required by DRAINS specified in Section 5 10 3 c This is the same as the format generated in the export process that creates MapInfo files from DRAINS data which you can see by exporting a small system and examining the resulting tables All the required information that is already in the GIS should be included in the files to be transferred It is then a matter of choice as to whether you add additional data in these files or enter dummy values and enter the missing data later in DRAINS DRAINS User Manual 3 7 November 2014 The following example illustrates the process paralleling the ESRI file import example Figure 3 12 shows the Oldtown System in Maplnfo with the data for one pipe being displayed This can be set up in MapInfo or in a text editor The corresponding node data is similar Gi Mapinfo Professional Oldtown _Nodes O idtown_Pipes Mz E File Edit Tools Objects Query Table Options Map Window Help Dlelalz lele aaam 42 Upstreamil 31 780 Downstrmil 31 380 Slope__ 0 046 TyPe Concrete under roads Nomdia 375 Roughness 06 Status Existing Zoom 594 9 m Editing None Selecting None Figure 3 12 The Oldtown Example in MapInfo From the MapInfo layers a DXF file containing a background for t
297. ng baseflows and user provided hydrographs 3 Gymea ILSAX Example Standard DRAINS XG File Edit Project View Draw Run Help olse S lalalala elinle e ale Pipe from Pit A2 to Pit A3 z c Pipename Pipe 4 2 Pipe length m 76 1 ii Upstream invert elev m 31 1 N Pipe Type OF ar Concrete under roads v Downstream invert elev m 29 608 Pipe 4 1 ICa z 1 i Slope 36 A m Nom Diameter mm 1 D mm 7 450 lt 450 i No of identical parallel pipes 1 Include Non Return Valve Pipe Roughness During Design runs this pipe Use default value 0 3 mm is new diameter and level can change aoe C is new but diameter and level are fixed is existing diameter and level are fixed Notes gt OK B Cancel QUANTITIES Survey Data Excavation volume 70 7 cu m Rock volume N A Scale off Length Length of trench deeper than 1 2m 64 8 m at an average depth of 1 25 m Help 4 Press F1 for help Figure A 15 Pipe Property Sheet Pipes and pits can be inspected using long section window called from the pop up menu for a pipe Figure A 18 and from the multi pipe long sections that can be created in the Export option in the File menu by specifying a route between pits Figure A 19 Pipe A 1350 mm Concrete under roads Length 76 1 m Upstream IL 30 244 Downstream IL 78 644 Figure A 16 Balloon Showing Pipe Data L hk are E ok See E
298. ng is more accurate The extended rational method gets overcomes most of these difficulties as it produces hydrographs using a rational method loss model The pipe system design method employed in DRAINS is dependent on having good information on pit inlet capacity relationships The best data is available from Queensland where overflows are larger than in southern states and more attention has been given to controlling them If good quality pit capacity data is unavailable the Design method cannot be realistically employed The design method can be applied with the rational method and extended rational method as well as the ILSAX hydrological model The design calculations for sizing pipes and determining invert levels are carried out using simplified assumptions and need to be followed by one or more analysis runs DRAINS allows hydrological models to be swapped easily so that it is not difficult to convert rational method models to ones using ILSAX hydrology Only the hydrological model and rainfall data need to be changed and the impervious areas for each sub catchment to be split into paved and supplementary areas The reverse change from an ILSAX Model to the rational method can be done even more easily This might be done to compare the results given by the models or to check an older design using rational method hydrology 4 3 3 Designing Infill Developments with On Site Stormwater Detention Systems Design work for re developments a
299. ng the program and inspecting some of its outputs The examples supplied run with the demo version of DRAINS and cover most of the methods available in DRAINS Chapter 2 deals with the many items and facilities in DRAINS It presents the menus that control operation the tools that define drainage system components pits pipes etc and the data bases used to store standard data It describes the data required for all components To illustrate these it works with a larger example involving both pipes and open channels Chapter 3 is about processes It describes the options within DRAINS for inputting and displaying information running the program outputting data and results and obtaining help Chapter 4 describes how DRAINS operates covering computing and computational aspects It also describes how DRAINS can be applied to design and analysis tasks indicating how runs can be made and how results can be interpreted Chapter 5 provides the technical background to DRAINS and the methods that it uses There are explanations and references relating to material on rainfall data overland flows pit inlet capacities and pressure change coefficients detention basins culverts and bridges The examples that were explained in earlier versions of this manual are now included in the DRAINS Help system They use files that are available at C Program Files Drains or C Program Files x86 Drains Previous versions of this manual described some
300. ng the surface flows arriving at each node by adding flows from the local catchment overflows from upstream and user provided flows Using the pit inlet capacity relationship bypass flows are determined The flow entering the pit is then added to any flows through upstream pipes and possible user provided inflow hydrographs to define provisional pipe flows When the calculations reach the system outlet or outlets DRAINS makes the upwards pass starting from the tailwater level at the outlet Allowing for pipe friction and pressure changes at pits it defines the position of the HGLs at pits and nodes and if necessary modifies the flowrates in the pipes and the corresponding overflows For part full pipe flow this process is carried out by projecting HGLs upwards and allowing for pressure changes at pits If a pipe flows full a pressurised flow calculation procedure is used to define HGLs at pits and flowrates in pipes Whenever it encounters a junction DRAINS projects HGLs up both branches from the pit water level If the calculated water level in a drop pit is determined to be below the invert level of an incoming pipe the tailwater is set at the critical depth in this pipe and upwards HGL projections are continued This model provides information on water levels at pits and nodes and flowrates through pipes When there is subcritical open channel flow the standard step method employing the Colebrook White or Manning s equation is used to comput
301. ng to the length allocated to the first pipe for which full data is entered The DRAINS Main Window then appears with the drainage system and background shown as in Figure 3 5 This can be enlarged if necessary using the Zoom tool The colour of the background and its intensity can be changed using the Background Colour option in the View menu If the background has a much greater extent than the pipes in the model DRAINS will reduce the field of view This can be extended again using the View Extend Drawing Area option Dummy pipes and pits can also be inserted to provide a large background as shown to the left of Figure 3 5 DRAINS User Manual 3 2 November 2014 Import Pipes and Pits from DXF File Fipes are on layer Fits are on layer Background is on layer optional Figure 3 3 Layer Selection Dialog Box Is the DXF file drawn to scale e Some If you answer YES all pipe lengths will be estimated based on the next pipe length you specify We suggest you pick a long straight pipe to specify Hint ar ae It is likely that many pipes are drawn in the wrong direction You should check them all and reverse them as necessary right click on the pipe and select Reverse Direction Figure 3 4 Messages in DXF Import Procedure You must now enter information for pits and pipes and draw in sub catchments overflow routes and outfall nodes as shown in the example in Chapter 1 Directions of pipes will have to be chan
302. ngineers Australia Canberra Goyen A G and O Loughlin G G 1999 Examining the Basic Building Blocks of Urban Drainage Proceedings of the 8 International Conference on Urban Storm Drainage edited by I B Joliffe and J E Ball Sydney Guo J C Y 1996 Street Hydraulics and Inlet Sizing Using the Computer Model UDINET Water Resources Publications Highlands Ranch CO with program Hare C M 1983 Magnitude of Hydraulic Losses at Junctions in Piped Drainage Systems Civil Engineering Transactions Institution of Engineers Australia Vol CE25 Hare C and O Loughlin G G 1991 An Algorithm for Pressure Head Changes at Pits and Junctions Urban Drainage and New Technologies UDT 91 Dubrovnik 1991 DRAINS User Manual R 1 November 2014 Heeps D P and Mein R G 1973 An independent evaluation of three urban stormwater models Research Report 4 Department of Civil Engineering Monash University Henderson F M 1966 Open Channel Flow Macmillan New York Huber W C and Dickinson R E 1998 Storm Water Management Model Version 4 User s Manual University of Florida for U S Environmental Protection Agency Athens Georgia Hydraulics Research 1990 Charts for the hydraulic design of channels and pipes 6th Edition Thomas Telford Ltd London Hydrologic Engineering Center U S Army Corps of Engineers 1997 HEC RAS River Analysis System Hydraulic Reference Manual Version 2 0 written by G W Brunner Davis Ca
303. niastaasaiaaiuasaiootuacviontecateahiceniootiacaionine 3 13 Orns JNAPOOUGUON tt cpeccticcssh ce aa Garecabensanscaus satuciots ex a a a a a 3 13 3 3 2 Screen Presentation Options cccccccccseccccesceccseeceeeeceeeeceeeeeseueesseeeesseeeseeesseeeeseneessegees 3 13 34 PRU CODUOI S yicccsseciciusticvaieacanetbiasisasasicusnticax ncaa ae seus nideaeit baad ota stare sd dar talaga aaa vas 3 16 g4 Design anov Analysis RUNS ies cam setemeesnace tenes E ees aaccesics aan cote metisa see anadantdng con cteuan asm 3 16 GAZ RUNES na wis Mae ocdaia duns Chain dusant Mut SA E E A AA E E divans 3 18 3 4 3 Warning and Error Messages ccccccseeeeceeeeceeeeeeeeeeeaeeeeseueeseaeeeseueeeseeeessaueesseeeessaeeesanees 3 19 3 4 4 Options for Modifying Pit Pressure Change Factors cccccccseeeeeeseeeeeeeaeeeeeeeeeseeeaeeeeeas 3 19 EAS Se ac chase ee a E ects aaneiaaes vaste eeat ouenntee aes 3 21 39 OUIDUT ODIOMS ronio o aa Sickie biaha i alols Sicko SA 3 22 3 5 1 Transfers of Displays and Screen Print Outs cccceccccecseeeeeeeeeeeeeseeeeeeseeeeeseeeeeeeseeeeeeas 3 22 3 0 2 DRAINS Print Diagram ODUON essed sseu tensa seueenncesececs sets E aa todesetaceeh sc ESN 3 23 399 DAFEN an a a ania veanmcnishd ane ienoore dent eedetane 3 23 3 5 4 Spreadsheet Outputs and INPUutS ccc cccceceeseeceeeeeceeeeeeeeeeseaeessesessaeeeseaeeeseneeesaaees 3 25 CoS ms he oid ca 4 6 0 ce ae ne on ee een nore Re er a a eyes Ree eee 3 30
304. nishing and constant components as shown in Figure 5 11 DRAINS User Manual 5 12 November 2014 AF N JA t Infiltration AFcap f At Baie N A mm h AF AF AF fe At AF ap gt ie At 7 fc Time AF o fy at AF Cap Figure 5 11 Infiltration Capacity Calculation Procedure f Combination of Hydrographs The time area method is applied separately to the paved supplementary and grassed area portions of the catchment DRAINS allows for a supplementary area depression storage and time of travel These must both be set to zero if you wish to exactly reproduce ILSAX hydrographs The process for paved and supplementary areas is shown in Figure 5 12 Hyetograph values are scaled by area 360 to convert intensities to flowrates in m s The more complex process for grassed area runoff is shown in Figure 5 13 This diagram is actually an oversimplification Some details not shown are that e the process is actually a step by step one mixing loss and routing calculations for a number of strips across a sub catchment and allowing for water running from one strip to another e supplementary area runoff is added to the grassed area flows and e depression storage is actually calculated after the infiltration is calculated HYETOGRAPH TIME AREA DIAGRAM HYDROGRAPH Intensity oe mm h Contributing Flowrate Area ha m3 s O gt Full Area convolved produces with Subtract
305. nly gt 0 5 m s 45 33 OK underestimate underestimate Combination with lt 0 15 m s OK OK OK 1m Grate Combination with 0 15 to 0 5 m s 5 overestimate OK OK 1m Grate Combination with gt 0 5 m s 20 20 overestimate 10 1m Grate overestimate underestimate DRAINS User Manual 5 31 November 2014 Velocities depths and other characteristics are obtained from normal depth calculations using the specified cross section from the overflow route cross section data base slope and roughness The HGL calculations associated with rational method in the urban stormwater drainage chapter of Australian Rainfall and Runoff and those in steady state hydraulics programs such as HEC 2 and HEC RAS are at the second level Several programs mostly proprietary ones offer full hydrodynamic modelling options using complex finite difference calculations These can give the most accurate results with an experienced hydraulically knowledgeable operator but can be subject to stability problems 5 6 2 Pipe Design Calculations In a design run DRAINS determines pipe sizes and invert level positions by calculating the peak flows of hydrographs entering a pipe system and designing for these in a downwards pass making certain assumptions The method considers both minor and major storms of different average recurrence intervals Pit sizes are also designed to keep overflows within safe limits defined in the overflow route data base The design procedure
306. ns C Gymea Clay ILSAX Model z o Came Note IF you want to edit a model other Delete Default Hodel than the default model make it the default model temporarily Edit Default Madel In addition to the leas model you may use Add ILSA Model one of the following models in this project l If you wish you may select one Add Rational Method Model pope Add Extended A ational Model C RAFTS Add Storage A onting Model C WENM Help Figure A 8 Hydrological Model Window Specifying an ILSAX Model DRAINS User Manual A 10 November 2014 Pee _ILSAX Type Hydrological Mode Model name Gymes Clay ILSA Model Paved impervious area depression storage mm Supplementary area depression storage mm 1 Grassed pervious area depression storage mm 5 Cancel Soil Type f Normal 71 to 4 3 Help f You specify Figure A 9 An ILSAX Model Property Sheet The soil parameter relates to a system developed by the US Soil Conservation Service Values from 1 to 4 are commonly selected based on the following descriptions Table A 7 ILSAX Soil Types 1 or A low runoff potential high infiltration rates consists of sand and gravel 2 or B moderate infiltration rates and moderately well drained 3 or slow infiltration rates may have layers that impede downward movement of water 4 or D high runoff potential very slow infiltration rates consists of clays with a permanent high water table and a
307. nt flows to two levels typically 2 and 100 year ARI often justifying the lower level on environmental grounds as a way of preventing erosion in natural streams carrying runoff from developments Compared to only having to implement this requirement at the 100 year ARI level this requires either a a more restrictive outlet and a larger storage volume or b double low level outlets Since DRAINS can easily model multiple storm events it is feasible to analyse all relevant design storms For example Table A 15 and Figure A 31 show results from the Sydney OSD Example with Results drn model in which three storms have been analysed In practice 6 to 8 storms would usually be required Table A 15 OSD Model Results Storm Duration Pre Development Post Development E Outflow m s Outflow m s 0 027 0 024 This model contains both the pre and post development systems so that they can be analysed together and the total outflows compared Inspecting the results it is possible to develop the following table of results from 100 year ARI storms DRAINS User Manual A 28 November 2014 3 Sydney OSD Example Standard dmn DRAINS XG File Edit Project View Draw Run Help Worst case major storm A Basin5 Inflow Outflow Hvdroaranhs AR amp R 100 vear 20 minutes storm average 147 mm h Zone f X 3 Basin5 Inflow Outflow Hydrographs AR amp R 100 year 30 minutes storm ave
308. o 1 0 3 Pit4 1 28 1 28 A1 9 Du Do 1 00 Qg Qo 0 19 S Do 1 1 4 Pits 1 87 1 87 Al 14 Du Do 1 00 Qg Qo 0 12 Do 1 1 5 Pit2 0 72 0 72 A1 5 Du Do 1 00 Qg Qo 0 13 Do 1 0 6 Pitl 5 93 5 93 A1 4 H Do 0 0 Vo2 2gDo0 0 02 T The Chart referred to in Column D is the one selected from those in the Queensland Urban Drainage Manual and the Ratios are those used to enter the chart to determine the k or K values Further details are given in Section 5 6 6 c The model will contain the revised coefficients The process of running the model and adjusting the coefficients should be repeated once or twice more to allow the procedure to converge to a fixed set of ku values Since values depend on flowrates and HGL levels this process must be run separately for minor and major flows in pipe system design generating different sets of coefficients The procedure for the Mills equation is similar but simpler Strictly speaking both procedures need to be applied iteratively since changing ku values will alter flowrates and HGLs which in turn influence the selection of the k values Two iterations might be usually required when using Mills Method while three or four iterations may be required using the QUDM procedure As indicated in the second message displayed for the QUDM procedure the changes made are presented in a spreadsheet placed on the Clipboard and this can be used to check that convergence has occurred k values created by this method can be
309. o be entered from a spreadsheet You must prepare two columns in a spreadsheet program such as Excel one containing times at fixed intervals in minutes starting at zero and the other containing the values of flowrates in m s You then select these columns and copy them to the Clipboard Switching from the spreadsheet program to DRAINS you can then open the Pit Inflow Hydrograph property sheet and import the data by clicking the Paste button The presence of baseflows or input hydrographs is not obvious when models are inspected They can be located by exporting the data to a spreadsheet as shown in Section 3 5 4 and inspecting the pit and node data Columns and P of the spreadsheet output Figure 1 33 show the values of baseflows and the presence of direct hydrographs 2 3 3 Simple Nodes The most basic type of node called a simple node can be used for several purposes e to represent an outlet e to act as a junction linking reaches in an open channel drainage system e to provide a junction for stream reaches in a storage routing model to actas a closed no loss junction in a pipe system and DRAINS User Manual 2 8 November 2014 e to provide a joining point for sections of overflow routes DRAINS detects whether a node is at an outlet to a system and if so it presents the property sheet shown in Figure 2 10 As explained in Chapter 5 for part full pipe flows DRAINS projects hydraulic grade lines upstream through a draina
310. o be transferred from the spreadsheet program to a word processor for inclusion in a report In connection with rational method calculations DRAINS has the option Edit Copy Check HGL to Spreadsheet that presents results of a simplified analysis of the drainage system using assumptions similar to those in the manual analysis procedures set out in Chapter 14 of Australian Rainfall and Runoff 1987 and Chapter 5 of the Queensland Urban Drainage Manual These results are not available for other hydrological models such as the ILSAX and extended rational method models For the rational method example shown in Figure 3 46 we can determine pit pressure change coefficients using the method from the outlined in Section 3 4 4 and run this model for minor and major storms We can then transfer the results of the simplified analysis to Excel in the form shown in Figure 3 47 Overflow routes from nodes have been provided at the tops of lines By specifying percentages of downstream sub catchments contributing it is possible to define the hydraulic DRAINS User Manual 3 28 November 2014 characteristics of approach flows in the spreadsheet output See Columns L to O of the Excel worksheet in Figure 3 47 This feature has been provided to assist persons documenting or checking designs It is more conservative than the DRAINS calculation procedures and will specify higher HGLs that might sometimes exceed the freeboard limits at pits It should the
311. o set the pit size and the pipe diameter and invert levels as fixed using options in the Pit and Pipe property sheets Both procedures allow for intermediate levels along a pipeline route between pits These are considered when pipe invert levels are determined allowing for minimum cover depths 3 4 2 Run Logs Following a run DRAINS presents a log reporting on the results as shown in Figure 3 28 indicating problems and possible causes The first example shows a trouble free run and the second one that has complex results DRAINS User Manual 3 18 November 2014 Run Log for Gymea Piped Drain Example dm run ai Upwelling occured at 150050 000310 100020 250060 250030 250020 450010 450020 530010 595010 440010 430010 450020 400010 080010 Freeboard was inadequate at more than 0 pits The masimum flow exceeded the sate value in the following overflow routes oO00042 0590011 jes 0020 o6000170 o610010 o650020 0430010 i Figure 3 28 Examples of Messages Reporting Results from Design and Analysis Runs The report must be closed by clicking on the X at the top right of the window but it can be recalled using the Last Run Report option in the View menu The information in the log is also reproduced in the spreadsheet output for results 3 4 3 Warning and Error Messages DRAINS performs a number of checks as data is entered One is to ensure that all the required data is provides In some instances DRAINS requires values to
312. o works 2D boundary elements ANUGA finite volume Integrated 1 D 2 D surface flow models MIKE Flood MIKE11 MIKE21 Sobek TUFLOW xp2d xpswmm TUFLOW Integrated 1 D 2 D surface flow models combined MIKE Flood MOUSE Sobek TUFLOW with unsteady pipe flow models xp2d xpswmm TUFLOW Reviewers can tell which hydraulic model has been used to produce a set of results from the status bar at bottom left of screen Information on the working of the models and their data requirements are given in the DRAINS User Manual and Help system Reviewers will mainly be concerned with the results particularly with the water levels estimated Methods of checking these are described in the following section In pipe system calculations peak flowrates are assumed to occur simultaneously in the rational method but in hydrograph models such as the ERM and ILSAX allowance is mode for the peaks occurring at different times due to varying times of concentration The calculation and checking procedure set out in ARR87 Tables 14 14 and 14 16 or Tables 1 14 and 1 16 in the 1998 version does not properly describe the processes in hydrograph models which usually specify lower HGLs An important issue in modelling beyond the scope of this Guide is the selection of a model that is adequate for the task Judgements on this require theoretical knowledge of hydraulics as well as experience with models The DRAINS pipe models have been tested and can be
313. of users have prompted considerable advances The original basic hydraulic model combined i hydraulic grade lines HGLS projected backwards from tailwater levels at drainage system outlets with ii a pressure pipe calculation procedure to calculate flowrates and HGL levels at pits and other locations using a quasi unsteady process DRAINS then computed the characteristics of surface overflows that cannot be carried by pipes This model has been replaced by a one dimensional unsteady flow procedure In the standard hydraulics model this is applied to pipe and open channel flows and in the premium hydraulic model surface overflows are also modelled by full unsteady flow calculations DRAINS User Manual 13 November 2014 c Additional Information on Models A more detailed coverage of the hydrological and hydraulic models available in DRAINS is provided in Chapter 5 These procedures reflect Australian urban stormwater drainage management practice which considers hydrological and hydraulic features in considerable detail as described in this manual and in the DRAINS Help system DRAINS is also adaptable for use outside Australia The ILSAX model is based on the American ILLUDAS program using the U S Soil Conservation Service soil classification and the Horton infiltration model is the same as that used in the US EPA Stormwater Management Model SWMM program Huber and Dickinson 1998 The rational method and ERM procedures are similar to
314. oisture condition 1 to 4 3 4 Annual Recurrence Interval pears Storm duration mins 30 Rainfall specified in Bo minute intervals 0 8 0 6 Time mins Intensity mm h o0te50 0 z Pastel Intensity mm h Comments f 15 20 Time mins Add one ARIE storm Add Synthetic Storm Add multiple ARRG storms Add a New Storm Help Delete Current Storm Figure 1 8 Rainfall Data Property Sheet Storm patterns or hyetographs can be defined easily in DRAINS by clicking the Add one ARR87 Storm button which opens the dialog box shown in Figure 1 9 Select a Pattern from Australian Rainfall and Runoftt x Rainfall Zone Figure 3 2 of ARRS Storm Duration fone 1 3 E Coast and Tasmania 25 minutes _ e fone 3 M E Coast zone 4 Timor sea and Gulf of Carpentaria fone 5 Central Australia fone 5 4 Gulf Zone 7 Indian Ocean zone d S5 Coast nee amp amp OK Cancel Annual Recurrence Interval years IFD Data Average Intensity mmh Help Figure 1 9 Australian Rainfall and Runoff Pattern Dialog Box Enter the information shown in this figure and press the OK button The pattern will be displayed in the Rainfall Data property sheet as shown in Figure 1 10 Note that there are other ways of entering rainfall data described in Section 2 4 4 Next change the antecedent moisture condition value in the Rainfall property sheet to 2 5 Setupa second pattern using
315. om one to six sets of ESRI or ArcView files plus an optional background from a DXF file The procedure is the reverse of the exporting process for ESRI files described in Section 3 5 5 a If you wish to model an existing drainage system in DRAINS importing data from available ArcView records you must edit these into the format required by DRAINS described in Section 5 10 3 b You can also scrutinise this format by exporting a small drainage system and examining the resulting DBASE tables The six sets of files contain data for nodes pits and outlets pipes overflow routes sub catchments survey levels along pipe routes and the positions of other services along a pipe routes Each set includes three files with SHP SHX and DBF suffixes DRAINS User Manual 3 4 November 2014 Ca YE Ve DRAINS Utility Spreadsheet Decer Rainfall Data ra Home Insert Page Layo Formulas Data Review Vie 7 Storm 3 4 of 3 Name 30 minute PMP Storm vr F G H Be 41071 Antecedent moisture condition 1 to 4 3 a Sy Annual Recurrence Interval years 5 110 5 Time Intensities ercentages i i 111 minutes mm h Storm duration mins 30 r 112 0 552 20 113 5 662 24 Rainfall specified in 5 minute intervals 114 10 552 20 E wn 115 15 497 1 Time mins Intensity mmh 116 20 331 r p 117 25 166 6 S astel 118 30 119 Comments i 10 15 20 120 Time mins i 4 gt i Rainfalls Ponding B
316. on basin at the location of the low point where overflows might occur with an elevation storage relationship based on the storage within the upstream channel High level outlets with weir data or a height discharge table can be used to control the overflows The premium hydraulic model allows a channel and overflow route to come out of the same node 4 Overflow links from a detention basin or headwall require more information than a normal overflow link to define high level outlets It is possible to have several high level outlets from a basin 5 Culverts and bridges must have open channels or routing reaches upstream and downstream Where a road is located at a point where stormwater emerges from a pipe or goes from on open channel into a pipe it is probably inappropriate to model this situation as a bridge or culvert If cross sections change under road in these circumstances the transitions can be modelled by pipe or open channel sections 6 While water may pond behind a bridge or culvert and even overflow over the top of the road DRAINS does not allow for any diversion of flows away from the downstream channel This might be modelled by locating a detention basin upstream of the device or perhaps by modelling a culvert as a detention basin 7 Bridges have more restrictions than culverts in DRAINS You cannot have two upstream channels meeting at a bridge as they can at a culvert It is necessary to insert a section of combined chann
317. on basin routing has to be explored by trial and error but the ability to edit the data quickly and re run the model makes this a fast process 4 3 4 Analysing Established Drainage Systems Established systems may need to be examined for deficiencies at particular locations such as problem areas where complaints of flooding have been made by householders or on an area wide basis taking in all drainage system components This latter type of investigation may be prompted by asset management or liability concerns rather than by particular experiences of flooding The processes in creating DRAINS files for Analysis are almost the same as for Design However all pits and pipes should be defined as existing Invert levels of all conduits must be defined The sources of the information required include e scaled plans showing road and cadastral layouts and contours e information on additions and remedial works for the drainage system e information on detention storage systems on sites or on public land e files detailing reports and complaints stemming from storm events and drainage system defects e any previous analysis studies relating to the area being considered e information on past storm events Since an existing system has to be modelled in some detail it will be necessary to draw information from GIS and data base sources If these are unavailable or inadequate it will be necessary to carry out topographic surveys to determ
318. on for Computer Aided Design Backwater Programs Publication M6 Melbourne Aitken A P 1975 Hydrologic investigation and design of urban stormwater drainage systems Australian Water Resources Council Technical Paper No 10 Australian Government Publishing Service Canberra Argue J R editor 2004 WSUD Basic Procedures for Source Control of Stormwater University of South Australia Water Resources Centre Adelaide Australia Bureau of Meteorology 2003 The Estimation of Probable Maximum Precipitation in Australia Generalised Short Duration Method www bom gov au has gsdm_document shtml ACT Government Urban Services undated Urban Stormwater Standard Engineering Practices Edition 1 www act gov au storm AUSTROADS 1994 Waterway Design Manual Sydney Austroads 2013 Guide to Road Design Part 5 Drainage General and Hydrology Considerations Armistead A et al Sydney BMT WBM 2010 TUFLOW User Manual GIS Based 1D 2D Hydrodynamic Model Brisbane Boyd M J Pilgrim D H and Cordery I 1979 An improved runoff routing model based on geomorphological relations Institution of Engineers Australia Hydrology and Water Resources Symposium Boyd M J Rigby E H VanDrie R and Schymitzek 2005 Watershed Bounded Network Model WBNM2003 User Guide University of Wollongong Wollongong download from www uow edu au eng cme research wbnm html Boyd M 1986 Head Discharge Relations for Culverts Monie
319. onal Method in DRAINS The models that are commonly used in urban stormwater practice in Australia are shown in Table A 6 These are only a few of the many models available but they are the ones that are sanctioned by manuals or have achieved wide use through promotion and recognition of their advantages Although DRAINS offers event models that run with rational method and ILSAX hydrology and emulate the RORB RAFTS and WBNM programs it does not perform continuous modelling of the type carried out by MUSIC Table A 6 Urban Hydrological Models Commonly Used in Australia Implemented in Loss Model Routing Model Rational Manual pipe design method in Method ARR 1887 and software derived Both loss and routing effects are incorporated in from this manual rural runoff the selected runoff coefficient C and the time of methods e g QUDM NSW concentration generation of hydrographs and Victorian probabilistic requires additional assumptions about volumes rational methods really regional flood frequency procedures ILSAX Model DRAINS similar models are Depression storages and Time area method applied in xoswmm Horton infiltration for pervious areas RORB RORB Initial and continuing Non linear storage losses routing RAFTS xprafts Initial and continuing Non linear storage losses routing also contains continuous ARBM model WBNM WBNM Initial and continuing Non linear storage losses routing Daily Rainfall Relatively simple Mu
320. one 2 Figure 1 11 Select Minor Storms Dialog Box The design process defines the pipe sizes and depths needed to carry runoff from minor ARI storms satisfactorily while meeting certain criteria The system must also fail safe in runoff from major ARI storms The system performance is checked using various analyses Now choose Options in the Project menu to open the sheet shown in Figure 1 12 This sets the values of parameters used in design calculations The only items to be entered in the present example are the blocking factors enter 0 5 for sag pits and 0 0 for on grade pits With this model you will be using New South Wales pits To select these choose the Default Data Base option in the Project menu The dialog box shown in Figure 1 13 appears allowing you to select the data base to be used Note that this must be done before any pits are entered into the Main Window The selected data base stays in the drn file for each model New pit pipe and overflow route types can be added and existing information can be altered but for programming reasons it is not possible to remove pipe and pit specifications At this point you should save the file using the Save option in the File menu or the diskette symbol on the Toolbar naming the file Orange1 drn The above processes create a template or shell containing the base information that will be used to run the model and the pipe pit and overflow route types
321. ons from 15 minutes to 3 hours for trunk drainage studies DRAINS User Manual A 7 November 2014 Rainfall Data Storm of 2 Hame ARGA 5 pear 25 minutes storm average 78 mmh Zone 1 Antecedent moisture condition 1 to 4 4 Annual Recurrence Interval pears z Storm duration mine 25 Rainfall specitied in B minute intervals Time mins Intensity mmh 00to50 TE z Paste Intensity mm h Comments F 10 15 Time mins T Age Swathetie Share Add multiple SARS storms Add a New Storm Help Delete Current Storm Figure A 5 Rainfall Data Sheet for Hydrograph Producing Models Select Minor Storms All storms z 5 ance f Select storms f Select ARI Help Aun Use Storm 1 ARR 5 pear 25 minutes storm average 78 mmh one 1 E Figure A 6 Window for Selection of Design Storms c Data for the Rational Method The rational method procedure available in DRAINS does not employ rainfall patterns but instead works from l F D information based on the eight rainfall intensities shown in Figure A 7 which appear when the Rainfall Data option in the Project menu is selected You can see this in the Gymea model by changing the hydrological model to a rational method in the drop down menu in the window that appears when Hydrological Model is selected from the Project menu d Other Rainfall Inputs Most Australian projects will employ the ARR87 design rainfall da
322. or design and minimum pipe diameters can be set for design in the manner described in Section 2 4 5 If the pipe s characteristics are already known its diameter and invert levels can be specified If it is not to intended to change these in a Design run the second or third choices in the During Design runs box should be selected The fourth choice only applies to the last pipe in a network It allows the system to be designed to match a specified pipe invert level at the outlet even if this violates constraints on the minimum allowable pipe cover and minimum slope The Survey Data button at the bottom of the sheet opens the property sheet shown in Figure 2 13 Survey Data for Pipe Pi 7 mm raeangs 0 oe Chainage at Pit 6 5 0 Help O K Chainage at Pit B G 11 4 Cancel Ground Level Details Services Crossing This Pipe Surface 9 Bottom Height Chg iml Level im Chg im Level ri rm 1 10 705 250 1 10 704 400 0 200 5 50 r05 450 9 00 O4 500 0 300 10 50 r05 280 Figure 2 13 Survey Data Property Sheet for Defining Intermediate Levels along a Pipe Line and Positions of Services DRAINS User Manual 2 10 November 2014 Surface levels can be entered at given chainages along the line of the pipe so that the design procedure can allow for minimum cover all along the pipe Intermediate points can be plotted in a long section drawing as shown in Figure 2 14 This property sheet also allows the positions of
323. orates optional storage routing models of the type used in the RORB RAFTS and WBNM programs that have been used in Australia since the 1970s and are applicable to broad scale rural and urban catchments of virtually any size As shown in Figure 1 3 they involve the division of a catchment into sub catchments based on streams and internal ridge lines Outlet Figure 1 3 Layout of a RORB style of Storage Routing Model within DRAINS Storage routing models treat sub catchments and stream reaches as storages similar to reservoirs or detention basins that can be modelled by the non linear equation S k Q where S is the storage in an element Q is the flow or discharge out of the element and k and m are model parameters These models work downwards through a catchment adding runoff from the various sub catchments and performing routing catchments that reshape the hydrographs The runoff routing modelling facilities in DRAINS can be configured to emulate the RORB RAFTS and WBNM modelling structures They can also be combined with ILSAX sub catchments and open channel hydraulic calculations so that quite diverse flooding and urban drainage systems can be described b Hydraulic Calculations for Pipes Open Channels and Surface Overflows The procedures in DRAINS originally were intended to be of a medium level of complexity providing stable fast and sufficiently accurate methods to compute flowrates and water surface profiles The needs
324. ous gt Pervious ear ae pe ry Pe peta rT i SOpe to E mope 0 g imin oo Te minor F List File name m Import options Hold obverts on import Generate results in plan Current model D PIPE ROAD Current pit R308 1 Generate results in long section Auto apply V Auto redraw v ae ESP Eo Set Pit Names Set Catchments Set Pit Details Regrade Pipes Plot i Import Export Storm Analysis PickEdt Apply lt lt gt gt _Finish Hep Figure 3 15 12d Drainage Network Editor Figure 3 16 12d Import Export Window e Now switch to the DRAINS model noted in Step a and from the Edit menu select Paste Data from Spreadsheet The model should then appear ready for a Design run f Run the model in DRAINS using ILSAX or rational method hydrology and the standard or premium hydraulic models Inspect the results and when satisfied send data to the Clipboard using the Copy Data to Spreadsheet option in the Edit menu g Using the Import Export button in the 12d Drainage Network Editor bring the data back to 12d h Going back to DRAINS press Edit Copy Results to Spreadsheet and in 12d press the Import Export button again to bring the remainder of the required information into 12d Note that this reverse data transfer must be done in two stages first data and then results For further details contact 12d 3 2 9 CADApps Ad
325. ouse button The names of components mostly given as to start with can be dragged to more convenient locations The components themselves can be moved round the screen You can select a component by clicking it to make handles appear holding the left mouse button down on it so that horizontal and vertical arrows appear and then dragging the component to the required location A pipe or channel can be moved as a single unit by dragging near its centre Alternatively their ends can be moved by dragging the handles As well as entering data directly onto a blank Main Window as shown above you can insert a background from a CAD drawing file together with a layout of pits and pipes A drawing file for the current example Orange Base dxf is shown in Figure 1 17 This can be entered into a DRAINS Main Window after the hydrological rainfall and options settings have been defined using the Import DXF File option in the File menu shown in Figure 1 18 This takes you through a set of dialog boxes in which you must nominate layers containing data on the background pipes as lines and pits as circles and other information The first of these is also shown in Figure 1 18 The pipe system appears as shown in Figure 1 19 This model should be saved as file Orange2 drn This view can be enlarged using the magnifying tool or mouse wheel and you can pan across the model using the pan tool in the toolbar All pipe lengths can be scaled by sett
326. outing GIS transfers GIS transfers and premium hydraulic modelling there are different forms of Some menus and property sheets to those described here These facilities are explained in the following sections together with the data bases that store information on hydrological models rainfall patterns and components such as pits The exposition is detailed and systematic and is likely to be boring unless you check through each item using the DRAINS demonstration examples or if you have a hardware lock to run the program fully the example file Toowoomba Estate Drn shown in Figure 2 1 3 Toowoomba Estate DRAINS XS File Edit Project View Draw Run Help Dem S lt le eene 9 Ql USX1 Ys Sy NB 2 P it B Cat 1 US B 1 ae mp Cat Ne PtB1 aps RH Geno Cole Q Qe OFB1a fatB 4 YE Pit B i ft N1 Pipe XT Pix i tor xa Cat C lapp AAT oe o ee if Ns Ve ti D 4 a Hw us rea i z p ABET OF 2 Silca o hn 4 Cat 3 OF C 1 N3 A ae nl 5 staf hn 6 Q a ott HW 6 Pipe By 1e 7 Cat 9 Chni 0 A Cik 8 Cat 0 N7 Crk 9a Bridge 9 5 Crk Sb N Ja Crk 9c N 9b N 9c Ss Ctk 6 tlet Press F1 for help Figure 2 1 Hypothetical Toowoomba Example 2 2 Menus 2 2 1 The Menu Bar DRAINS employs seven drop down menus opened from the items in the menu bar Fie Edit Project View Draw Run Help The broad functions of each menu are described below You will find material on individual functions in other parts
327. ove the floor level The perimeter of the walls at different elevations can be defined in the table The hydraulic conductivity depends on the type of strata through while infiltration occurs Further information is provided in Argue 2004 Conductivities DRAINS User Manual 2 25 November 2014 are quite small and in most cases need to be specified in scientific notation For example a conductivity of 2 x 10 m s can be specified as 2e 6 DRAINS specifies these as 2e 006 The page on the Detention Basin property sheet tagged Initial Water Level shown to the right can be used to make a basin part full at the start of a storm Usually it is assumed that the basin is empty Use of this facility may result in some reverse flows at Data Initial Water Level nfittration Data the start of a storm eee Set by DRAINS The last component required to define a detention storage is the C You specify high level outlet which is described in the property sheet for the overflow route from a basin When an overflow route originates in a basin the property sheet has three pages instead of the two shown in Figure 2 25 and Figure 2 30 Two of these pages are the same as those in those figures On the third page labelled Weir Data you have the choice of specifying a weir outlet as shown in Figure 2 38 or an elevation discharge or height outflow relationship as shown in Figure 2 39 Overflow Route OF T a Basic Data Weir Data
328. ovember 2014 In the premium hydraulic model pipes open channels and overflow routes are all modelled by the same procedures based on open channels Closed pipes can be treated as being open by using a Priessmann slot Figure 5 28 Each link has a representative cross section so it is necessary to divide open channels and overflow routes into separate links where their geometric characteristics change f id Pi i Slot a few mm wide eN Full Pipe Pressurised Flow Part full Flow Figure 5 28 Priessmann Slot for Modelling Pipes as Open Channels At sag pits there will be two HGL levels one describing the water level in the ponded runoff at the surface and the other describing the pipe HGL Calculations for outlet weirs from sag pits detention basins headwalls and culverts use tables of elevation vs discharge To cover the situation where tailwater levels below these controls are high in the premium hydraulic model DRAINS uses the Villemonte equation to modify the table if the downstream water level is above the weir crest the level in the table at which Q 0 The Villemonte equation allows for submergence of the weir QG Cr Ci h 2G beh Equation 5 19 where Q is the flowrate m s Cy is the discharge coefficient dimensionless g is acceleration due to gravity 9 80 m s b is the effective width of the weir m h is the effective head m and Cy is a drowning factor equal to Cg A 1 hz h1
329. ows a On the first model draw two dummy pits 100 m or 200 m apart Give them distinctive names Pit details should be filled in but the exact information entered is not important b Export the model data to a spreadsheet using the procedures in Section 3 5 4 c Open the second DRAINS model and export the data from this to another worksheet in the spread sheet Among the PIT NODE outputs insert two additional rows d Return to the worksheet created from the first DRAINS model and copy the two rows describing the dummy pits Paste these into the two blank rows in the worksheet for the second model Then copy the whole worksheet to the clipboard e Return to the second DRAINS model and use the Edit Paste Data from Spreadsheet option to bring the two dummy pits into this model 3 Toowoomba Addition DRAINS x File Edit Project View Draw Run Help osje a oleam oleuo of al Gam jan Cat C 1 Pipe CPt C 2 Durnmy Dutlet2 Press F1 for help Figure 3 60 The File that is to be Added using the Merge Options DRAINS User Manual 3 36 November 2014 3 Toowoomba Estate DRAINS XS File Edit Project View Draw Run Help BAE olema m o vlel Ella o ale US x1 Cat B 2 Cat B 3 Cat B 1 BT Q Pit B 2 Pipe B 2 Pit B 3 US BT N ATA Fa DFB 3 Pit B 1 t Pipe B 1 Te ewewee eee n Pe Ba YF Cayx Jii OF B ta saci i i Siae S Cat 1 CatB 4 oP
330. pecial pipe type and size in the Pipe Data Base as described in Section 2 4 5 DRAINS User Manual 2 23 November 2014 Detention Basin gt Data initial Water Level Infitration Data Name Basin5 Low Level Outlet Type connecting to a pipe Dia mm 105 Bevin 404 mmh 2 3 4 5 6 T a Note The prismoidal formula is used to calculate volumes from suface areas Click Help for more details Cancel Anny Hep Figure 2 34 Detention Basin Property Sheet with Orifice Outlet Detention Basin as Data initial Water Level Infitration Data Name 27 0 5 27 3 0 5 28 1720 H __ is Paste Table Note The prismoidal formula is used to calculate volumes from surface areas Click Help for more details Pit Sump Circular culvert Rectangular culvert None Be om Bn f amp fw Ra a NSW RTA SA Inlet 3 crossfall 1 grade coca oon vee Figure 2 35 Detention Basin Property Sheet for a Pit Sump Outlet For some basins in low lying areas where backflows may occur a non return valve may be specified in the Pipe property sheet Only one low level pipe can exit from a detention basin with specified invert levels The required size and invert levels cannot by determined in Design runs but must be established by trial and error using analysis runs DRAINS User Manual 2 24 November 2014 Pipe 6 5 Pipe 4 74 Figure 2 36 Arrangement for a Basin with a Pit Sump Ou
331. pill over the road centre line The road centre line forms a parabolic weir crest You define the parabola by specifying just one point at say 10 m from the low point along the road centre line Horizontal distance from low point m 10 Height above low point m 02 Note This data is used in the premium hydraulic model only The basic and standard hydraulic models assume zero depth over the weir at a sag pit Figure 2 27 Weir Properties Page in Overflow Route Property Sheet This is to provide a hydraulic control representing a barrier such as the crown of a road or an entrance to a property There are three choices on the page a rectangular weir e a parabolic weir representing a vertical road alignment and DRAINS User Manual 2 18 November 2014 e ageneral depth discharge relationship that can be set up on a spreadsheet and transferred to DRAINS The rectangular weir requires a weir width the coefficient is taken to be 1 7 the parabolic relationship requires a depth at a given distance from the low point as shown below while the elevation discharge relationship is more general Since the premium hydraulic model must deal with potentially very high flowrates in 100 year ARI and PMP storms it models situations where there are chains of storages and overflow routes The storages are likely to be at sag pits but can also occur at ponding locations that are created in large storms The overflow routes
332. ponents The inputs for these components are described in other parts of this chapter while the inputs for the discontinued culvert object will be described in the Help System If the obsolete culvert object has been used in an older DRAINS model it will re appear when this model is opened with the current version of DRAINS 2 3 16 Bridges The property sheet for Bridges is shown in Figure 2 55 Because of the differences in shapes abutment and pier arrangements and approach conditions bridges are more complex that culverts In DRAINS calculations are performed using a relatively simple method provided in the AUSTROADS 1994 manual which is based on the US Federal Highway Administration report by Bradley 1970 More complex bridge modelling procedures are available in HEC RAS MIKE 11 and other open channel hydraulics programs DRAINS results should be checked using these programs if the accurate determination of levels is critical You will need to refer to the original references to understand the inputs required fully It is necessary to specify e the name of the bridge and the levels of the deck m and the soffit underside of deck m e the weir coefficient for overflows over the bridge deck typically 1 7 e pier width locations of piers as noted in Figure 2 56 and pier type e the abutment type and the X Y coordinates at the bridge section m left overbank main channel and right overbank Manning s roughnesses and the
333. pth im 015 an inverted pyramid greater depth overflows 2 C You specify a table Max ponded volume cu m 2 Figure 1 22 A Drainage Pit Property Sheet Next you can enter the sub catchments e as shown in Figure 1 20 The sub catchment symbol should no be placed over a pit If this is done it will snap to the top right corner of a pit and can then be moved to another location around the pit if you wish The data for sub catchments is entered into their property sheets which are opened from a pop up menu in the same way as for pits The simplest form of the property sheet is shown in Figure 1 23 The sub catchment draining to each pit is divided into three types of land use e paved areas impervious areas directly connected to the drainage system e supplementary areas impervious areas not directly connected to the drainage system and e grassed areas pervious areas A time of entry is assigned to each land use This is the time that it takes for stormwater to flow from the furthest boundary of each type to the point nearest to the pit The supplementary area drains onto the pervious area If the grassed area does not extend to the pit a lag time is specified to account for the time taken for this grassed area runoff to pass over the section of paved area near the pit Times can be calculated using the equations and guidelines presented in Section 5 3 2 d DRAINS User Manual 1 15 November 2014 The parameters for all sub catch
334. r Manual 2 31 November 2014 Multi channel from N4 4 a Cancel Channel 1 of 2 prismatic Help Edit channel data Delete this channel Add prismatic channel Add irregular channel Add circular channel Figure 2 47 Multi Channel Property Sheet 2 3 13 Stream Routing Reaches This link type shown as Py is used with the RORB and WBNM storage routing models to connect nodes and sub catchments as described in Section 5 4 and to perform non linear routing Its exact function differs between the two models as they have differing structures The RAFTS storage routing model describes stream reaches using the same overflow routes that were used for pipe systems described in Section 2 3 6 If a RORB storage routing model is selected the property sheet for its stream routing reaches appears as shown in Figure 2 48 A reach name and length must be specified and a Channel condition selected If a channel condition of excavated unlined or lined or piped are selected it is also necessary to provide the reach slope The RAFTS stream channel property sheet shown in Figure 2 49 is identical to that for an overflow route from a pit A name is required and if Simple translation no attenuation is chosen in the box labelled Flow Routing Method a travel time through the reach must be entered With a RAFTS model this can be zero if a conservative result is required Overflow Route Reach B2 m Basic Data Name
335. r Rocla Technical Journal November Bradley J N 1970 Hydraulics of Bridge Waterways Hydraulic Design Series No 1 Federal Highway Administration U S Department of Transport Washington DC Cartwright A P 1983 The Application of ILLUDAS to an Urban Drainage Catchment in Sydney Australia Master of Engineering Science Project School of Civil Engineering University of NSW Chan A 1998 Retrieval Processing and Analysis of Rainfall Data from the Hewitt Gauging Station 1998 1999 Undergraduate Project Faculty of Engineering University of Technology Sydney Chaudhry M H 1993 Open Channel Flow Prentice Hall NJ Chen J J J 1985 Systematic explicit solutions of the Prandtl and Colebrook White equations for pipe flow Proceedings I C E Part 2 Vol 79 June Chow V T 1958 Open Channel Hydraulics McGraw Hill New York Dayaratne S T 1997 Quantification of the Errors in Urban Catchment Rainfall Runoff Models A Review 24 Hydrology amp Water Resources Symposium Auckland 1997 Dayaratne S T 2000 Modelling of Urban Stormwater Drainage Systems Using ILSAX PhD Thesis School of the Built Environment Victoria University of Technology Melbourne Engman E T 1986 Roughness Coefficients for Routing Surface Runoff Journal of Irrigation and Drainage Engineering ASCE Vol 112 No 1 February Goyen A G and Aitken A P 1976 A Regional Stormwater Drainage Model Hydrology Symposium Institution of E
336. r broad area sub catchments and calibration to different data sets and c modelling choices by users Some models allow users much more scope than others For routine applications such as OSD calculations designers probably should choose models accepted by approval authorities while for more complex or critical applications the more scientifically proven and calibrated models will be the ones that can best model situations and be most easily justified The basic hydraulic model that was used from the first release of DRAINS has been replaced by the standard and premium hydraulic models which are based on different principles and are more rigorous and stable Because both of these models allow for volumetric effects in stored and flowing runoff they calculate lower flowrates than the old basic hydraulic model with the premium model usually giving the lowest flowrates and HGL levels DRAINS User Manual 4 20 November 2014 Xg 5 TECHNICAL REFERENCE 5 1 Introduction This chapter sets out the background and the technical basis for the procedures used in DRAINS Some features such as the ILSAX hydrological model were inherited from other programs while others were developed specially for DRAINS 5 2 Predecessors DRAINS is the result of a chain of development that originated with the U K Transport and Road Research Laboratory TRRL Method in the early 1960s TRRL Method UK 1962 ILLUDAS US 1974 y ILLUDAS SA South Afric
337. r outside the designer s organisation using the DRAINS Viewer which is free A reviewer can open all property sheets in a model and export data summaries in spreadsheet format If a DRAINS file contains stored results these can also be viewed and exported to spreadsheets CAD outputs and system diagrams can also be exported but other types of output are not available It is not possible to edit or run files in the Viewer Since reviewers have direct access to models it should not be necessary to provide elaborate printed sets of results to reviewers However some converter spreadsheets have been developed to transfer results from ILSAX and rational method models to tables similar to those in Australian Rainfall and Runoff and the Queensland Urban Drainage Manual These are available as downloads from www watercom com au see the last item on the downloads page Since DRAINS runs rapidly and its results are quite apparent it is easy for consent authorities such as municipal councils to run files and inspect the results or else to view these using the DRAINS Viewer As discussed in Section 4 3 4 files prepared by consultants can be retained and incorporated into the authority s DRAINS model of its overall drainage system The results provided by an appropriate ILSAX hydrological model are likely to be superior to those obtained using the rational method since allowance can be made for multiple storms and detention storages and major system modelli
338. rage 121 mm h Zone 1 Detention Basin File Edit Properties Data Initial Water Level Infiltration Data 0 04 Name Basin5 Eev Surf Area m sq m 0 035 Low Level Outlet Type connecting to a pipe 1 40 275 1 0 03 Orifice Dia mm 105 2 41 34 1 i 0 025 C Pit Sump E 3 41 35 1 E Circular culvert fa el 40 4 4 41 36 7 0 02 Rectangular culvert 5 41 37 14 0 015 Other or None 6 4138 21 7 4139 28 2 0 01 sjans 5 a 0 005 0 _Paste Table 0 20 40 60 80 100 120 Note The prismoidal formula is used to calculate volumes Time mins from surface areas Click Help for more details High Early Discharge Notes 0 025 0 025 Ce 0 001 40 36 R G z 41 58 Q 0 009 0 003 aT T l T 40 18 Hep gt For Help press F1 Figure A 31 On Site Detention Model Results Thus it is possible to ensure that post development flows peaks are held to pre development levels for all storms analysed When modelling pre and post development conditions it is important that the same hydrological model is applied to both cases with adjustments to allow for increased development and imperviousness Reviewing Open Channel Systems Open channel systems can be set up in DRAINS by specifying a number of reaches with appropriate cross sections and parameters Different procedures are applied for the basic calculations and the unsteady flow standard and premium hydr
339. rage Routing Models ccccccceecceecseeeeeeeeeeeeesaeeeeseeeeeeeseeeeeesseeeeesseeeeeesneeeeeens 1 28 2 MENUS TOOLS AND DATA BASES ZW MOUI E E E EA 2 1 EL 2 Se ee A A A 2 1 Zee TAON ONU BAT e e EEE EEEE E EIE AE TE EEEE AEAEE 2 1 2 TACE ME cea E E E E E de suetcseceeetsaaeceee 2 1 229 Tie CN TGA saer E E E E aise E E E EEEE AE E ER 2 2 22 4 The Project Ment co cicdvannidsanacciatavaisebawkantuadeasaaniatwaceuliaenaganolaesendacheectetinaidabiabanane ieda aaa 2 2 2 2 5 The View Menu aio ssccceccv tcc ncescccreiieuieaetesnctenestiees elec ndactebutesviecuscesieuecssoieuiianiecteossteviecasiaceegeeeees 2 2 RLO MVS SGA VOT ee gs is sgesec sas posted said EE E E A E E ace coeds tp encoun eee nioen ene ER 2 2 224 The RUN MONU scscsecizy actanteck avcaniicn oetenpeesusaanccts EE E E E E EERE Er 2 3 2 2 8 The Help Me nu cccccscccssccceseeceeeccaeeceueecececauecaueesaueesaeescaeeceueesaueesaeessaeessueessuesaueeseneessas 2 3 2 3 Tools and Associated COMPONEMMS ccccecceccseeceeeeeeseeteeeeeeteeeeeeeeeneeteeeneees 2 3 Dew T E A E E E A E A E ETET 2 3 DO FANS enie a a teen oan E a neues ancsiavecs E iE 2 4 Dd OMP NOG OS a sra reeds eased ce cee es iecene Seca deen eee 2 8 7 ae AC PIOS ee ee ee eee A E eee eee eee ee 2 9 2939 SUIS AUC AC IMS ae dese heh occtct cepted deste baste a aaia aa aaae 2 11 2 39 60 Overflow ROWS Scie cette ne estersirronie iieiea eaaa Gon dace See ad a a 2 17 BOE DONIN BASIS srecsctesee eorex
340. rate cu m s 2 S Negative Flow Time mins Figure 4 5 Complex Flow Hydrograph 4 2 10 Design Procedures The pipe design process in DRAINS makes a pass down the various branches of a drainage network from pits at the tops of lines to the main outlet At each pit it determines the maximum pipe outflow allowing for inlet flows flows in upstream pipes and any baseflows or user provided direct hydrograph flows It then determines suitable pipe sizes and invert levels taking account of e the roughness and the allowable cover depth associated with the chosen pipe type e the values set of minimum pipe slope pit freeboard and fall in the Options property sheet opened from the Project menu e a restriction preventing pipes decreasing in diameter as the calculations move downstream e likely pit pressure changes at pits in full or part full pipe flows and e the hydraulic capacities of pipes with various diameters and slopes In 2014 an enhanced design procedure has been introduced Following a design by the original procedure a review is carried out that reduces pipe sizes where possible It provides a message saying how many pipes were able to be downsized Pipes reduced by more than one size increment will only be counted as one pipe downsize It may still be possible to improve on a DRAINS design by manually downsizing pipes although there is much less scope to do this than with the original design procedure If you try to
341. raulic model g the Analyse minor storms basic hydraulic model There is also the Design option that sets pipe sizes and invert levels and options for revising pit pressure change factors and outputting pipe quantities The alternative hydraulic models are described in Sections 4 2 7 and 0 The standard model that replaces the obsolete basic model applies unsteady flow calculations to pipes and open channels but not to overflow routes The premium model applies the unsteady calculations to all three types of conduits The models can be run with either the set of minor or the set of major storms established in the rainfall inputs using Select Storms gt Minor storms or Select Storms Pb Major storms options in the Project menu see Section 2 4 4 When any of the above options are chosen DRAINS launches into a run There may be warnings and a request to use parallel processing Once these are noted are acted upon the run begins Rational method calculations are quick because only peak flows are generated and there are no unsteady flow calculations The simulation runs used with the other hydrograph producing models will take longer to run and will produce much more comprehensive results Analysis runs treat all pipes as fixed and do not alter the given pipe diameters and invert levels Complex situations such as pits with the invert of the outgoing pipe being higher than those of the incoming pipes can usually be modelled For pipe
342. refore be considered as a guide or sanity check rather than as a true representation of the peak HGL levels Among the reasons for conservatism are that peak flowrates in all pipes are assumed to occur simultaneously 3 Gymea Rational amp ERM Example Standard DRAINS X File Edit Project View Draw Run Help pleal S olela l lt a m olveaa la p Sub Catchment Data Rational Method eae Sub catchment name eaa Sub catchment area ha 0 08 Use Hydrological Model abbreviated data Use default C more detailed data C You specify Impervious Pervious Percentage of area 80 20 Time of Concentration mins 25 3 Cancel Help mW r Press F1 for help Figure 3 46 Rational Method Example FE Gymes Rational amp ERM Example Standard DRAINS S File Edt Preje Verw Dew Rum Help Or AS T P k a Y i kn ki B O al w Pa K E T E k Paa T AEN s p A a ee N i WOON te a oN SO NO OU Pa i N a 3x W beer 7 Bookl Microsoft Excel Ela x f Fie Home Insert Page Layout Formulas Data Review View Add Ins Acrobat v o E 2 a T58 F E a A B c D E F G H J K L M N o P Q R s T uy 1 This provides a simplified analysis using QUDM procedures that can be checked manually and is useful where Council insists on a manual check on HGLs E 2 The HGLs shown here may be different to the more accurate values calculated by DRAINS for several reasons including 3 i For pipes flowing part full if
343. reports submitted to reviewers c The Rational Method and the Extended Rational Method DRAINS also offers a procedure that carries out rational method calculations This can be viewed in the Gymea model by choosing the Hydrological Model option in the File menu and selecting the Gymea Rational Method model shown below Default Model for Design and Analysis Runs G pmea Rational Method Gumea Rational Method Lymea ERM Separate areas lymea ERM Total areas This can then be viewed by clicking the Edit Default Model button The model that appears is likely to be an ARR87 model using the procedures from Australian Rainfall and Runoff 1987 as shown in Figure A 11 Rational Method Mode Model Nane Grmea Rational Method Rational Method Procedure Imperious Area C10 Value 0 9 C General Pervious Area C10 Value 0 51 These C10 values are 10 pear ARI runoff coefficients They will be adjusted automatically to suit the SAls C AS 3500 3 2003 specited for major and minor storms 0K Cancel Help DRAINS User Manual A 12 November 2014 Figure A 11 Property Sheet for a Rational Method Model This model uses two runoff coefficients 0 9 for impervious areas and 0 51 for pervious areas The latter is based on the 10 year ARI 1 hour duration design rainfall intensity for Gymea as described in Section 14 5 5 of ARR87 Section 1 5 5 of Book 8 of the 1998 version The rational method averages these runoff coef
344. rial developments In some cases reviewers may only require a statement or certification that a certain requirement has been met for example that a roof drainage system has been designed according to AS NZS2500 3 OSD is a particularly complex issue and many methods can be applied some involving reservoir routing others employing simple calculations based on factors such as permissible site discharges and site storage requirements specified by the council or drainage authority Specified ARIs for on site detention OSD systems vary from council to council and designers must address stated local regulations The current trend appears to be to analyse OSD systems for two levels a low ARI such as 2 years and a high 100 year ARI The low ARI requirement is likely to have the greatest influence on the storage required Another trend is to specify double outlets in series or parallel which are difficult to analyse DRAINS can accomplish this and allow for high early discharge pits Stormwater detention systems are discussed further in Section A 5 A 3 3 Inter Allotment Drainage Systems Also known as easement drainage systems these are pipe and flow path draining through lower properties to a street As well as a a pipe they involve b an overland flow path to carry flows exceeding the pipe capacity and c legal documentation defining the easement rights of access and prohibitions against obstructions The usual requirements are DRAINS Us
345. riorates and defects due to damage and ageing of assets become apparent e remedial works are constructed and e design standards change DRAINS can be easily updated to reflect all these changes Periodic reviews can be made using the DRAINS model which becomes a permanent feature of the drainage authority s asset management system Many municipalities and stormwater authorities do not have full information on their systems Nevertheless they can start with this incomplete data setting up data bases and models with the available information and then refining these Experience during storm events special surveys to determine pit and pipe invert levels CCTV inspections preparation of lists of trouble spots and asset registers will provide added information so the records can be gradually expanded and the modelling improved As shown in Figure 4 14 DRAINS provides transfers to GIS programs in the form of ArcView shapefiles and MapInfo MID MIF files The connection of DRAINS to the GISs of drainage authorities allows the results of DRAINS analyses to be included in the GIS These can include flowrates and hydraulic grade line levels for average recurrence intervals of 1 2 5 10 20 50 and 100 years plus probable maximum precipitation PMP storms see Bureau of Meteorology 2003 These results can be mapped and displayed in many ways using colour coded symbols and lines The GIS can also act as a means of querying the underlying databas
346. rojects NSW Pits June 2006 db1 ACT Fits June 2008 db1 NS Pits June 2008 db1 Queensland Pits June 2008 db1 Help South Australian Pits DecUS db1 South Australian Pits July 2000 db1 Victorian Pits June 2008 db1 only used in different WA Pits Movember 008 db1 You can edit or change the default data base at any later time Figure 2 80 Dialog Box for Selecting a Default Data Base However there are many types of pit for which no relationships are available Using the HEC22 procedures in the wizards for on grade and sag pits implemented by the buttons shown in Figure 2 79 inlet capacity relationships can be estimated for these A generic pit spreadsheet that calculates capacities using methods from the US Federal Highway Administration HEC 22 manual US FHWA 2001 can also be applied More explanation is provided in Section 5 5 3 If a Pit Data Base is opened and a change is made to the data for one of the pits the following message appears when this is closed by clicking on the OK button Clicking the Yes button sets up the file s pit data base as the selected one DRAINS e i A Do you want to save the pipe data base changes in Drains db1l P Drains dbl is used each time you start a new file Various regional pit types are available as dbi files in the C Program Files Drains Program folder If ACT Pits June 2008 db1 or Queensland Pits June 2008 db1 is copied as Drains db1 into the folder C Program
347. rom this system which occurs when a pit overflows but no overflow route is provided to convey this overflow In such situations the model should be amended The message also indicates that there are no overflows from the pipe system and that freeboard is adequate that is the peak pit water level is more than the minimum freeboard allowed normally 150 mm to meet a requirement mentioned in Section 3 4 B Run Log for Gymea ILSAA Example drn run at 13 02 07 on 15 6 2011 ater was lost from the systernn at Pit A 1 ls this corect If this water re enters the system further downstream vou should draw an overflow route from this location No water upwelling from any pit Freeboard was adequate at all pits Figure A 21 Run Report In designs there should be no upwelling or other problems at the Minor flowrate but these can be permitted under major flow conditions usually 100 year ARI storm events Itis also possible to view other characteristics using the Customise Text option in the View menu This changes the display to the form shown below J9 aam 30 8 ZIM 016 Sty RE FFM Figure A 22 Displayed Surface and Pipe Invert Levels DRAINS User Manual A 23 November 2014 Results can be viewed in more detail using options in the pop up menu displayed by right clicking on components These can display hydrographs and HGL plots as shown in Figure A 23 and long sections of pipes Figure A 18 Tables of results can also be display
348. roughness mm sometimes termed e and DRAINS User Manual 5 33 November 2014 v is the kinematic viscosity taken as 1 14 x 10 m s at 15 C The pipe wall roughness values in Table 5 21 are recommended by Hydraulics Research 1983 and the Standards Association of Australia 1978 Values for other materials are also given in these publications Table 5 21 Recommended Colebrook White Roughnesses k Hydraulics Research SAA Recomm Pipe Material Recommendations endations for values mm concentrically pipe condition jointed clean Concrete Precast with O Ring Joints Spun precast with O Rings oos f ons Monolithic construction against 2 15 0 03 to 0 15 steel forms Monolithic construction against l rough forms woe O S S S Spigot and Socket Joint oo Manning s Equation is 1 Vea g gt Equation 5 21 n in which V is velocity m s n is a roughness coefficient R is the cross section hydraulic radius m area wetted perimeter A P and S is longitudinal slope m m 5 6 6 Pit Pressure Changes a General The head losses and changes to the energy grade line and hydraulic grade line at pits and junctions are extremely important in determining pipe system behaviour accurately Figure 5 29 shows how these are represented by two functions of the pit outlet velocity V for full pipe flow Grate Flow Figure 5 29 Pit Energy Losses and Pressure Changes The TEL w
349. route information for this example is shown in Table 1 4 The percentages of downstream areas are used to define flow characteristics along the overflow route as explained in Section 2 3 6 DRAINS User Manual 1 17 November 2014 Finally the outlet names and levels must be defined Here it is assumed that the main outlet operates as a free outfall The tailwater level for the pipe system will be the higher of the normal and critical depths for the outlet pipe unless this is running full Outlet surface levels are specified in Table 1 1 Overflow Route OF 1 __ Basic Data Cross Section Data shape 8 m wide road half section E Li a X m Safe Depths and Flow Rates Safe Depth for Major Storms m 0 3 SE win er eee re Use default values for this cross section Tai Degli ka Mar Stree be 015 15 You specify Safe Depth x Velocity sq m sec x of downstream catchment flow camied 0 by this channel This adds a percentage of the sub catchment flow at the downstream pit to the overflow rate allowing Channel slope flow characteristics to be calculated at points all along the overflow route cows te Figure 1 26 The Overflow Route Property Sheet Page 2 Table 1 4 Overflow Data for Orange Example Travel Time of D S Flow Path minutes _ Yo a ANE EE E A E Tors s owes 1 oP o F4 Pita outet2 1 o0 1 ors Prs Outett 1 0 1 As these changes are made you should
350. rovided necessary results Pipe long sections Table of quantities Outputs from DRAINS may be provided Roof gutter and downpipe calculations Generally only required where consequences of failure are significant Pipe design calculations Tables of results from DRAINS may be provided Roof gutters and downpipes are sized to prevent water for storms of a specified ARI overflowing the edges of gutters The commonly used design chart from AS NZS2500 3 is based on hydraulic theory and testing but methods also incorporate factors of safety such as freeboards differences between peak water levels and edges of gutters ARIs of 20 years are commonly used for eaves gutters on the perimeters of buildings and 100 years for box gutters that span buildings Pipe systems should be sized according to the consequences of failure in case of overflows although some councils specify required ARIs The usual range is from 5 to 20 year ARI The ARIs for surface drainage can be smaller than those used for roof design depending on the relative consequences of failure Pipe design methods for property and inter allotment pipe systems are generally simpler than for street drainage networks partly because the specification of minimum pipe sizes to prevent blockages leads to overdesign of smaller systems Typically requirements are less strict for small developments or for single dwelling developments compared to multi unit residential commercial and indust
351. rred to a spreadsheet or report It forms the basis for the design variations and checks that may be required For a small system data can be entered from the keyboard into property sheets as described in Chapter 1 For larger systems it is likely that information will be transferred from a CAD file as described in Section 3 2 2 or from DTMs such as 12d and Advanced Road Design Imported data can be augmented with data entered directly into the property sheets for components The information for a component is retained when it is copied and pasted using the Copy Shape option in the pop up menu for a component and the associated Paste Shape option It is often easier to copy and paste an existing component and to modify its data rather than to enter all data each time an object is created For large systems the spreadsheet outputs and inputs described in Section 3 5 4 can provide an efficient means of entering repetitive data Components can be entered with nominal values and can then be edited in the Data spreadsheet before transferring the information back to DRAINS The process is shown diagrammatically in Figure 4 11 Start with Standard or Template File with Hydrological Model and Rainfall Data Set ae Transfer Data and Background v from Drawing or Digital Terrain Modelling Program uu Enter Actual or Nominal Data into DRAINS File v Transfer to System Data Spreadsheet 4 Edit Data in Spreadsheet ti Complete Base File and
352. rs Australia 1987 page 303 DRAINS User Manual 5 22 November 2014 Q 1 66 P d up to about 0 12 m of ponding Equation 5 16 where Qis inlet flowrate m s P is the perimeter length of a grated pit excluding the section against the kerb and d is the average depth of ponding m Orifice flow can occur above 0 12 m for a grate and 1 4 times the slot height for a kerb inlet though there is a large transition zone for grates in which either flow mechanism may occur Most cases of interest to designers including major flows are described by the weir equation At low flows all of the approach flow will be captured but at a certain flow some bypass will start to occur i 2m Kerb inlet depressed 25mm Flowrate captured Source N S W Department of Main Roads 1979 m s lm undepressed Kerb Inlet for various longitudinal slopes 0 0 02 0 04 0 06 0 08 0 10 0 12 0 14 0 16 0 18 0 20 0 22 Gutter Flow approaching Inlet m s Figure 5 20 Entry Capacities for Kerb Inlets on Grade There have been many sets of hydraulic tests undertaken to define inlet capacities Tests have been conducted in Australia by the NSW Public Works Department for the NSW Department of Main Roads now NSW Roads and Maritime Services and NSW Department of Housing by the University of South Australia for various Queensland Australian Capital Territory and South Australian bodies and by the Victorian Country Roads Board VicRoad
353. s These have produced a rather confusing array of results from which it is difficult to generalise In addition the published relationships do not cover the range of high flows expected to occur in severe storm events such as 100 year average recurrence interval and probable maximum precipitation events Almost all studies were intended to develop relationships for routine design and did not deal with very high flows Extrapolation of these relationships is an uncertain process The main factors influencing inlet capacity of on grade pits are the length of the pit the depression or crossfall of the gutter at the pit and the longitudinal slope Generally the greater the longitudinal slope the lower the capture rate Pit size and grate type are the main factors affecting sag pit capacities The US Federal Highway Administration Hydraulic Engineering Circular No 22 Urban Drainage Design 2009 includes a set of semi theoretical procedures for defining inlet capacity relationships Pezzaniti O Loughlin and Argue 2005 have used these as a basis for extrapolating existing relationships and for developing relationships where none are available 5 5 2 Pit Inlet Capacities in DRAINS At every time step in DRAINS calculations the program applies pit inlet capacity relationships to the surface flow arriving at each inlet If the flowrate arriving at an on grade pit causes the storage to exceed its specified volume the surplus flow becomes a bypa
354. s In Analysis there may be upwelling of flows from the pit due to the capacity of the downstream pipe system being insufficient to carry the assumed flows As shown in Figure 4 3 these are added to any bypass flows to define the total overflow from the pit Approach Flow ines Bypass Flow Overflow Inflow Upstream Pipe Flows Downstream Pipe Flows Figure 4 3 Pit Inflows and Outflows DRAINS User Manual 4 4 November 2014 No overflows can occur at simple nodes or from ILLUDAS type pits now obsolete Situations where overflows or breakouts occur from channels might be modelled by adding a detention basin at the overflow location as noted in Table 2 2 The calculated inflow rates at each time step can then be used as boundary conditions for the main set of calculations through a pipe or open channel system These provide information on HGLs and water surfaces at nodes and flowrates through the various links within a system With the rational method only peak flow conditions are considered but for hydrograph models conditions are calculated at each time step b Basic Hydraulic Calculations In the basic calculations that are now obsolete drainage systems are analysed by making downwards and upwards passes through the pipe or channel network at each time step going from each pit or node to the next one downstream or upstream The first pass moves downwards from the top of each line in the system establishi
355. s provided here Likewise DRAINS can be put to many uses and it is not possible to cover all of these The DRAINS training workshops provide information of this type though examples and exercises 4 2 DRAINS Workings 4 2 1 Units DRAINS uses metric units throughout Where possible it follows SI conventions for these but in many displays and outputs it is not possible to show superscripts Thus cu m and cu m s are frequently used in place of m and m s 4 2 2 Programming DRAINS is written in C and works on PCs with Microsoft Windows operating systems from Windows 95 to Windows 7 The calculation procedures from the PIPES program are used to model pressurised flow situations It inputs and outputs data in binary spreadsheet CSV DXF ESRI shapefile MapInfo MID MIF and data base formats DRAINS is structured so that different hydrological and hydraulic models can be run via the same interface with many functions being shared such as the display of hydrographs There are choices of e Hydrological models ILSAX storage routing and extended rational method producing hydrographs and rational method producing peak flowrates e Hydraulic calculations standard or premium hydraulic model calculations and perhaps for older models the obsolete basic model calculations and e Procedures design of pipe systems or analysis of pipe open channel and detention systems The free DRAINS Viewer operates in the same way as DR
356. s Fhe Win Grae Sarija i i f eo Tee Cunber We 3A irri To Steir rea Ca qi re 7 15 To 30 fie Cor To Cobo 13 Bara darm 1 mE Ei Hom 2 1mm Bearing Bare g hs P 50 and P 50 x 100 Section AA Ee DRAINS User Manual it Gutter Face Slope degrees 90 Manning s n of Road 0 014 Manning s n of Gutter 0 012 Adjustment Factor os kerb Inlet Length im Width of Depressed Gutter or Grate m Length of Grate m 45 Tilt Bar Laie Fe oe 5 29 November 2014 Reticuline P 30 Figure 5 24 HEC22 Pit Types Once the required data is entered the required relationship will appear in the Pit Data Base property sheet This can be checked by copying this and displaying it in a spreadsheet This procedure can be applied to pits in swales as well as in street gutters or channels The dialog box is shown in Figure 5 25 covering the situation shown in Figure 5 26 Inlet Type Grate Type C Grate in Street 0 Reticuline C Kerb in Street 30 degree 85 Tilt Bar l Kerb Grate in Street Grate in Swale C 45 degree 85 Tilt Bar 0 Curved Vane Channel Bed Width m Longitudinal Grade 2 2 Channel Side Slope 1 7 V H J Width of Grate m 1 Channel Depth m E Length of Grate m 1 8 Manning s n of Channel Inward Slope of Base used when base width exceeds grate width Figure 5 25 Dialog Box for a Pit in a Swale Side Slopes 1 x
357. s by Bob Stack for the design and analysis of piped water supply systems Full pipe flows were modelled using steady flow DRAINS User Manual 5 1 November 2014 equations and a graphical user interface was provided which became the bases for the interface in DRAINS 5 2 1 DRAINS DRAINS grew out of attempts by Geoffrey O Loughlin to provide a successor program to ILSAX A joint venture with Bob Stack of Watercom Pty Ltd yielded a program that combines an effective user interface from Watercom s PIPES programs with the ILSAX model and a much improved pipe and channel hydraulics system Development took place from 1994 to 1997 and has continued to the present time with important developments being shown in Table 5 1 Table 5 1 Significant Developments in the Capabilities of DRAINS Date Development o O procedures for pipes and open channels 1999 Addition of spreadsheet input output 1999 Introduction of rational method procedures 2001 Introduction of the Advanced Design Method with new pipe pit and overflow route data bases 2002 Introduction of storage routing models emulating procedures in the RORB RAFTS and WBNM programs March 2006 Introduction of fully dynamic unsteady calculations for pipes open channels and overflow routes 2007 Use of DRAINS Utility Spreadsheet to prepare input data externally February 2008 Introduction of Queensland Urban Drainage Manual QUDM procedures for automatically determining pit pressur
358. s some part of a sub catchment that does not drain to the drainage system for example a hollow or depression in volcanic areas it should be excluded from the model Generally fully developed medium density residential catchments will have areas impervious between 30 and 70 Dayaratne 2000 has obtained the following relationships from modelling of storms on 16 gauged residential catchments in four Victorian municipalities DRAINS User Manual 5 6 November 2014 Directly connected impervious area or paved area percentage DCIA 0 85 hha 23 38 hhd 101 19 r 0 90 Equation 5 1 Supplementary area percentage SA 0 04 hhd 1 13 hhd 3 79 r 0 91 Equation 5 2 where hhd is the number of houses ha These equations produce the numbers shown in Table 5 2 Table 5 2 Estimates Paved and Supplementary Area Percentages Housing Density hhd Paved ae DCIA Supplementary houses ha Area As noted in connection with Figure 2 16 supplementary areas may be used to model systems where roofwater is discharged onto grassed areas d Overland Flows and Times of Entry Times of entry must be specified for the paved and grassed areas and also for the supplementary area in DRAINS These are effectively the same as the times of concentration or times of travel used in the rational method They set the base lengths of the time area diagrams used to create hydrographs The DRAINS property sheet for a sub catch
359. s such as road embankments or existing buildings a flood study may be required even for small projects Councils determine whether such studies are required relying on reports of past flooding and area wide modelling that reveals likely riverine and local overland flooding situations The extent of the work required can vary considerably with the situation Where stormwater runoff can flow freely through or beside a development it may be relatively simple to define a design flowrate and flow path geometry and to determine flow characteristics such as depths and velocities However complex situations may require careful assessment of areas upstream and downstream of the development site and involve extensive hydraulic modelling DRAINS User Manual A 6 November 2014 As shown in Table A 5 study report is usually required setting out the pre and post development situations the methods applied and the results Table A 5 Typical Requirements for Assessing Localised Flood Studies Flood study report describing the effects of The report must be consistent with flooding on the proposed development and construction plans of the development measures taken or needing to be taken to prevent damage It will be necessary to demonstrate that the new development does not increase the flood hazard affecting future occupants of the development adjoining and downstream property owners and the public The results will usually focus upon 100 year AR
360. s that have the specification shown in Figure 3 27 the Design option selects pit sizes from the specified pit family for each pit and defines the pipe diameters and invert levels for circular pipes Design cannot be performed with rectangular pipes If you have already specified invert levels these will most probably be changed in a design In calculations the second option in Figure 3 27 is treated exactly the same as the third except that when DRAINS calculates quantities of soil volumes for excavation volumes for pipes defined under Option 2 are included in the table of quantities along with those defined under Option 1 volumes for Option 3 pipes are not During Design runs this pipe is new diameter and level can change C is new but diameter and level are fixed 0 is existing diameter and level are fixed Figure 3 27 Specification of Pipe Types DRAINS does not specifically try to design around existing pipes with fixed invert levels so situations will be encountered where it is not possible to do this while obeying the restrictions set in the Options property sheet opened from the Project menu In these cases the invert levels at the downstream end of designed pipes may be specified as being lower than the existing pipe to which they connect The design method applied based on the Queensland Urban Drainage Manual Neville Jones amp Associates et al 1992 varies both pits and pipes to obtain an optimal result It is possible t
361. s worst condition is noted in the last column for each component DRAINS does not transfer the specific results for each individual storm If you wish to do this you should use the Select Storms option in the Project menu to run DRAINS with single storms and transfer the results one at a time The velocities shown correspond to the peak flowrates and may be part full or full pipe velocities depending on the conditions when the maximum flowrate occurred A continuity check of inflow and outflow hydrograph volumes at each node presented at the bottom of the spreadsheet shown in Figure 3 45 applies for the most severe storm It shows up differences in continuity due to factors such as the absence of an overflow route when overflows occur However it does not show any discontinuity due to the introduction of a baseflow or a user provided inflow hydrograph Where there is a lack of continuity at a node the cause can be explored by examining the inputs and outputs to the relevant node using the View Hydrographs and View Hydrographs as Tables options in the pop up menus for pipes channels overflow routes and sub catchments The run log that appeared after the run completed is also presented at the end of the Results output Home Insert Page Layout Formulas Data Review View Developer Acrobat wU A1 v fx DRAINS results prepared 12 January 2011 from Version 2011 01 ra A s c D F G j K L M N o p Q R s T 111 112 DETE
362. sections This has been omitted in the current version of DRAINS but may appear in older models It is described in the DRAINS Help system DRAINS User Manual 5 8 November 2014 The property drainage time is that required for all water to contribute to flow at the boundary outlet There is conflicting evidence on property drainage times Stephens and Kuczera 1999 Goyen and O Loughlin 1999 Dayaratne 2000 with some pointing to short times 1 or 2 minutes and some to longer times 5 to 10 minutes 1 to 2 minutes is recommended as being reasonably conservative In DRAINS a lag time for grassed area flows can be applied where flows from such areas pass over paved surfaces before reaching a pit as shown in the lower part of Figure 5 8 The time to be entered is the flow time over the paved area supplementary Area Flow Path Paved Area Flow Path Zero Lag for Grassed Area Flows in this case Grassed Area Flow Path Outlet Grassed Area Lag Time or Factor allows for travel over _ this path Grassed Area Flow Time is for travel over this path Figure 5 8 Lag Times and Factors The Queensland Urban Drainage Manual QUDM 2008 recommends a simplified procedure for setting inlet times using the values in Table 5 4 Should the calculated t be less than 5 minutes this minimum value is customarily adopted as the t Table 5 4 Recommended Standard Inlet Times in Queensland Urban Drainage Manual a a
363. ser Manual 2 13 November 2014 c a street gutter or channel segment where a flow time can be calculated from an estimated velocity along the gutter Times a and c can be added to form the constant time in the property sheet A lag time can be used to delay the grassed are area runoff hydrograph by a time representing the travel time of runoff over an area of impervious surface between the lowest point on the grassed surface and the pit or node at the catchment outlet This is illustrated in Figure 2 19 It might be used to model a constant flow time along a street gutter or channel Supplementary Area Flow Path N Paved Area Flow Path Zero Lag for Grassed Area Flows in this case Grassed Area Flow Path gt Outlet Grassed Area Lag Time or Factor allows for travel over this path Grassed Area Flow Time ts for travel over this path Figure 2 19 Explanation of Lags b Rational Method Sub Catchments The property sheet has a very similar format to the ILSAX model sub catchment property sheet the main difference being that sub catchments are being divided into pervious and impervious areas instead of paved supplementary and grassed An example is shown in Figure 2 20 Sub Catchment Data Rational Met Son Sub catchment name Cat ET Sub catchment area ha 0 528 Use Hydrological Model C abbreviated data more detailed data You specify Impervious Pervious Percentage of area
364. ses eee see E E EEE EEE 2 22 2 3 8 SOESCIal Weirs and OCES ase cs eis dass nsieacidahsnnssien gcien E aii aaa a ia aaia a N ai a aiii 2 27 Band POND S eena en E A E axe sana E E E E E E A 2 28 2 3 10 Prismatic Open Channels ccccccccesccceeseeceeeeeceeeecencesseeeeseuseeseueeeseacesseueessaeeeseueessueeesagees 2 28 2 11 kreg lar Opan Channel eserssea e n E E N E 2 29 23 12 Mul CHannelS sasesana tee Sencdeceensee 2 31 2 3 13 Stream Routing REACNES ccccccceeeceeceeeeeeeeeeeeeeseeeeeeseeeeeesseeeeeeseeeeeesseeeesseeeesseeeeeesseeeeeeas 2 32 2 09 14 Hedwall acsee a E T 2 34 PASSE E N TE E EE EA E A A E T E A E 2 35 aie ed 6 DOOS a ee ee nee eee ee eee ee er ee eee eee en cn ee eer eee re 2 35 2 9 10 COMPDIPRING AS OMMPONGINS neseuriconceesaurrucetalauieesdadenbaaadssesunaatesuaeegedaceaneaendiasdudnmes SEEE aE 2 37 DRAINS User Manual i November 2014 4 ZA Wala BASCS casessscacecnaececesnatenaemeaasacamnaeeaaestanesanwe OEE 2 38 De Generalna a A Gia ecele AA A desea 2 38 2 4 2 Standardised Data Bases ccccccccccccseeeeeeceeeeeeeaeeeeeeeeeeeeeaeeeeesseeeeeesaeeeeeseeeeeeeaeeeeesaeeeeeeas 2 38 2 43 Hydrological WIOCCIS xa2s ccndavtucs avecaaacecsatutinta e a 2 39 24 4 Ranta Data Bases sis ies cieiees debt Hueco gcsdewehd a a a dieees yk ieee 2 40 PE emma ne 0121 8 F212 iets e E E RSET Ede eR SE a 2 48 240 PMD ale BASEen stecea hanes niet dnc aes tate naevus he aetna eee eee at 2 50 24r Ovemlow Route
365. sh to vary cover depths with pipe sizes or to have different classes of pipes with different wall thicknesses specific pipes classes should be entered as pipe types Once established the data base is easy to apply Pipe types and sizes are readily accessed from the Pipe Data property sheet The data base can be edited and factors such as cover depths can be altered When such changes are made the title should also be changed to note that the default set of pipe data has been altered Additional pipe types can be added using Import gt DRAINS Database DB1 File in the File menu which requests the name of a db1 file to be added These are usually located in the C Program Files Drains Program folder When a file is nominated DRAINS opens the dialog box shown in Figure 2 77 You can then select the particular data you wish to transfer DRAINS User Manual 2 48 November 2014 Note that deletion of pipe types and sizes is not possible if pipes are present in the Main Window It can be done on a template file that does not contain any drainage system components When a DRAINS file is opened and closed its pipe pit overflow profile data bases remain in DRAINS and some may be inherited by the new system Template files can also supply suitable data bases Pipe Data Base Pipe Type Concrete under roads Add Concrete not under roads UPVC under roads u FYC not under roads IFRC Class 1 FRC Class 2 Properties IFAC Class 3 FA
366. sing the stream pattern and the internal ridge lines as shown in Figure 4 15 The CatchmentSIM software Ryan 2005 can do this if suitable topographic information is available Sub catchment areas channel reach lengths and other characteristics are then measured The number of sub areas should reflect the detail of the information required and the important features of the catchment such as reservoirs and changes in the type of channel DRAINS User Manual 4 18 November 2014 Streamflows and other data suitable for calibration of the model are then assembled Ideally there should be at least three recorded flood events Loss parameters and initial values of the parameters ke in RORB BX in RAFTS and C in WBNM are established The program is then run and the outflows are compared with the calibration data or rural catchment flood estimates developed by methods in Chapter 5 of Australian Rainfall and Runoff Institution of Engineers Australia 1987 The parameters are then adjusted and the final calibration flowrates determined If more than one storm event is available for calibration it may require different parameters to obtain exact matches to recorded peak flows A compromise set of parameters must then be selected le lt Reach Cat C f Mode Q Reach C a7 2 No ee i Pa Reach B CAL E n Outlet Reach 0 Figure 4 15 Layout of a RAFTS Storage Routing Model With the parameters established the model can be used to estima
367. skingum Cunge Runoff continuous daily rainfall routing between Model model with disaggregation storages for shorter time steps The revision of Australian Rainfall and Runoff see www arr org au is likely to change the preferred hydrological models with some of the methods in Table A 6 being superseded DRAINS will adjust to accommodate any new methods recommended by Australian Rainfall and Runoff The Extended Rational Method is not included in the above table because it is not yet widely used in Australia Now available in DRAINS it provides the capability of a hydrograph producing model using rational method runoff coefficients to practitioners who prefer the rational method DRAINS User Manual A 9 November 2014 In many situations two or more of these models can be validly applied to a catchment but they are likely to provide different estimates of flowrates A particular model can also give widely varying results when applied with different loss and routing parameters In routine applications such as the design of a subdivision drainage system guidance can be obtained from manuals but for more difficult applications experience and judgement are needed to select an appropriate model and its parameters b The ILSAX Model The ILSAX model will be considered first To inspect the models in DRAINS choose the Hydrological Models option from the Project menu to open the window shown Figure A 8 The buttons on the right allow models
368. ss If overflows occur due to limitations on pipe reach capacity these are added to the bypass flows Two types of entry conditions can be modelled in DRAINS e sag pit at a low point where water will pond up to some limit with any overflows being directed downstream or out of the system when the ponded water level rises to the spill level DRAINS User Manual 5 23 November 2014 e on grade inlet on a sloping gutter from which any flows bypassing the inlet can run away with bypasses or overflows being directed to downstream pits or out of the system At one stage there was also an ILLUDAS pit type that no longer appears in DRAINS It is described in the Help System Initially DRAINS followed ILSAX O Loughlin 1993 by using equations employing various curve fitting factors but this approach was superseded by inlet capacity relationships defined as a series of points as shown in Section 2 4 6 rather than by equations Further information is given in the DRAINS Help system Sets of inlet capacity relationships are available to users of DRAINS in the new format These were obtained from published sources mostly smoothed graphs fitted to experimental data from the testing rigs operated by the University of South Australia www unisa edu au uwrc rig htm and the New south Wales Government Manly Hydraulics Laboratory hittp mhI nsw gov au www welcome html The new relationships have been extrapolated well beyond the ranges of the publ
369. storm The limited size is due to restrictions on the size of column headings in the database files used in ArcMap After this is entered the process is finished 3 Gymea ILSAX Example drn DRAINS Edit Project View Draw Run Help Close Save Save As Import gt Open Os So o O Q amp y Export b DXF Long Section Print Diagram Ctrl P DXF Plan 1 Gymea ILSAX Example drn 2 Gymea Rational amp ERM Example Standard drn 3 Toowoomba Estate drn 4 Penrith ARR87 Example Standard drn 5 Armidale drn 6 Taree Model Chapter 2 enlarged network drn Merge File 7 ilsax10 drn Drains Template File ESRI Shapefiles Mapinfo Files 12D Connection Data File Advanced Road Design File Tuflow TS1 Files 8 Shepparton RORB Rural drn Exit Save As Save in H ehe bia Recent Places ci E Date modified No items match your search DRAINS User Manual 3 31 Type November 2014 Figure 3 50 Nomination of Shapefile Name Suffix for result fields inthe GIS SYT Cancel Create new files f Add results to existing files Note Ifyou add results to existing files it is your responsibility to ensure that the existing GIS files are current ie pipes pits etc in the GIS are an exact match for those currently in CRAIN S IF you are unsure wou should choose create new files Figure 3 51 Naming of Set of Results If
370. sults stored in computer memory to be inspected Export Import file file Stored data and results in spreadsheet DXF GIS or Data base formats Figure 4 1 Typical Processes in DRAINS Performing calculations in Action b is a batch process Once started it continues without intervention by the user unless it is aborted by pressing the Esc key On the other hand Actions a c and d are event driven They can be carried out in many different ways depending on your preferences The programming style follows Microsoft Windows conventions so that it will be familiar to most users The main calculation procedures in DRAINS are e hydrological calculations which produce the flowrates to be transported through the drainage system e the hydraulic design procedure for pipes which determines pipe diameters and invert levels allowing for minor and major storms and e hydraulic analysis calculations for pipes and channels which define flow characteristics such as discharge rate velocity and depth and determine whether systems can convey flows without overflowing Applications using hydrological storage routing models may only apply the first of these procedures DRAINS User Manual 4 2 November 2014 4 2 5 Initial Processes The various run options are described in Section 3 4 Before these become available in the Run menu DRAINS performs checks to confirm that e a hydrological model and rainfall patterns
371. t Export menu presents the message in Figure 3 56 If you continue you will then need to nominate a filename for MID MIF files in the dialog box shown in Figure 3 57 for nodes including pits etc pipes pipe survey data services crossing pipes catchments and overflow routes 2 You are about to export data to a set of 6 MIF files These include data Each MIF comprises a set of 2 files with the extensions MIF and MID so that a total of 12 files will be created You can select any one of these existing MIF files and DRAINS will update all 12 files Or you can enter a new name and DRAINS will create 12 new files based on variations of that name eg enter MyJob to create MyJob_Pipes mif etc The next step is to specify the file name Continue Figure 3 56 Message in MapInfo File Export Procedure DRAINS User Manual 3 33 November 2014 Save in piGmea Name Type 2 Gyrmea2_Catchments mif E 12 01 2011 4 36 PM MIF File nnnnnnnunanunnnnnnnununnnnunnnunnnnnnnunnnnnnnnnn unnn nnn n 1 Gyrmea2_OverflowRoutes mif 12 01 2011 4 36 PM MIF File 1 Gyrnea2_Pipes mif 12 01 2011 4 36 PM MIF File 1 Gyrnea2_Services mit 12 01 2011 4 36 PM MIF File I Gymea2_Survey mif 12 01 2011 4 36 PMs MIF File 4 File name Gymea Nodes mit Save as type Mapinfo MIF files mif Figure 3 57 Nomination of MID MIF File Name You can see from the existing files in this example how six MapInfo MIF files are established Anot
372. t E E E AE E A E E E ee eee 5 43 2102 Drawing ile FOMAI srota a a a ou ecuses 5 43 5 10 2 GIS FIS Formals einan E E E eile tet Oh aaseece 5 44 5 10 4 Spreadsheet File Formats ccccccccccsececceeeeceeeeeeeeeseeeceseaeeeseaceeseeeeseusesseeessneeessnseesegees 5 46 521035 TUFLOW FST FIS ROmMatS is3sscie tains ea ona a oaa 5 47 A THE DRAINS VIEWER AT IAVOQUCHON n E A ee eee eee A 1 A 2 Setting Up and Running the Viewer ccccccecceccceeeceeeceeeceeseeeseeeseeesaeeseeeaes A 1 A 3 Information Required for Checking ccccccecceeeceeeceeeceeeseeceeeseeseeeeeeseeeaes A 3 Pron STC Ali EAEE E A A sadnoeb Gad E eas nos A AE dade only mend wanes A 3 A32 Property Drainage SV SlemSsxsiasicenueiecetancesiates ition uieeeeatdan A A nase weeded A 3 A 3 3 InterAllotment Drainage Systems ausernee ete eee ieee a A 4 AS Ay Street Drainage SYSlCMS acuittieaiise cane Nena ide co ee siete nd a ceases A 5 ASO Trunk Drainage SY SiC INS eaor iee Sac a acetate a aaa es Packer aa eee oes A 6 AS 6 t calsed Flood Sades gasa a a a sided eS Ghats tide Mees A 6 A 4 Assessing Models and Inputs cccccccccsecceeeeeeeeeeeeeeeeeeeeeeeseeeeeeseeeeeeaeeaees A T AAT C2 21 gt Pree tee te ee te T a er a A T A4 2 Rainfall IMPUS annn tidied Oa eet ei A ee ise ae A 7 PV PY ONO eea os encase rare as et aaedeh cose case usenet sumed meee ae Genre A ceeenecmeoutes aman A 8 A 4 4 Comparison of Hydrological Methods for Piped Drainage
373. t PRATT ie Pont PEAT C20 eae a mM heme UERR Gi Attributes of Oldtown Fo Shape name DRAINSID LENGTH UPSTREAMIL DOWNSTRMIL SLOPE x TYPE NOMDIA ROUGHNESS STATUS NUMPIPES Pf o royine Peas 219 _3205 _31 78 0 012 Concrete under roads 200 o6 Exstng 1 Poyine Peas 87 s7e 21 38 0 046 Concrete underroads 375 o6 Existing J lovne Poe Seef staf sozr 002 concrete underroads srs o6 Estno a8 27 soor 0 008 Concrete under roads 375 06 Existing e2 oor 0 024 Conerete under roads 37s o6 Existing se a 0 003 Concrete under roads aso 06 Existing 3 0 007 Concrete under roads 480 0 6 Existing s 282 0 022 Concrete under roads 480 o6 Existing B el ss ass 2575 ase Goncrete under roads 600 0 6 Basting 2 Poyine Peec 2s 215 2895 0009 Concrete under roas 300 o6 Existing io Poyine Pec2 _ s _2695 2835 0013 Concrete underroads 300 o6 Existing resem ecs ava amas avs ana ome woweeis 208 08 em sa 22 285 oote concrete underrosds 300 08 exstng ma ss 2575 0 083 Concrete underrosds_ 300 08 Eestng ar a 2625 02 concrete underrosds sts 08 Eestng 2 2rsr 2707 0 008 Concrete under roads 375 06 Existing 2787 0 031 Concrete under roads 300 06 Existing Pees2 es soas a8 cone under rods soo 06 ing 3035 0 021 Concrete un
374. t produce only peak flows and to apply different forms of rainfall data hyetograph patterns and intensity frequency duration F D relationships with these model types It is possible to develop a number of different ILSAX models say for different soils and to mix these in a model The storage routing models can be mixed with ILSAX models although it is only possible to have one type You cannot mix RORB and WBNM models for example However it would be possible to create a DRAINS model that used three kinds of ILSAX model and two kinds of RORB model The extended rational method cannot be mixed with any other model Three different kinds of rational method model can be applied as shown in Figure 2 59 and you can inter mix these Rational Method Mode m ModelName Genernc Rational Method Rational Method Procedure Rational Method Model General C ARRG bodel Mame Orange Rational Method f AS 3500 3 2003 Rational Method Procedure Imperious Area 010 Value 0 9 C General S Imperious Pervious F AERE Pervious Area C10 Value 0 26 AMD el etait ile Live estan se wai f AS 9500 3 2003 These C10 values are 10 year ARAI runoff coefficients as They will be adjusted automatically to suit the ARI Runoff coefficient C major stoarme 0 30 0 55 specified for major and minor storms Rational Method Model S OK Model Name Building Design Rational Method FAational Method Procedure Soll iz C General f Clay C Other
375. ta For specialised studies actual recorded storms or other required patterns can be imported into DRAINS from spreadsheets or simply typed in PMP data from the Bureau of Meteorology and special data for the Gold Coast City Council area can be obtained from the DRAINS Utility Spreadsheet located on the CD accompanying this Guide If required these spreadsheets can be submitted to reviewers A 4 3 Hydrology A 4 3 1 General All the designs or analyses described in the previous section require the estimation of design flows otherwise the use of hydraulic calculations is a case of garbage in garbage out Designers rely on methods set out in authoritative manuals such as Australian Rainfall and Runoff 1987 and the DRAINS User Manual A 8 November 2014 Queensland Urban Drainage Manual 1992 2007 but these are far from perfect due mainly to the dearth of available data for calibrating and testing models Rainfall Data for Rational Methoc ARI pears 6 Minute Rainfall Intensity mm hour 1 Hour Rainfall Intensity mini hour 44 4 12 Hour Rainfall Intensity mm hour 11 1 72 Hour Rainfall Intensity mm hour 3 48 Note The Intensities shown above are LPM values obtained from the Bureau of Meteorology or Councils If these are not readily available you can use the ARR Wizard with values you read from Australan Faintall and Runoff Volume 2 maps to calculate therm Figure A 7 Rainfall Data Used with the Rati
376. ta with the old 1987 temporal patterns The new design rainfall intensities can be converted to design patterns in DRAINS using the Single Entry procedure described in Section 1 2 1 a in Figure 1 8 to Figure 1 11 The steps required are i Define a table of rainfall depths for the design location specified by latitude and longitude entering additional Standard Durations as required Analysis Location Ri C Nsw el Standard Durations Label Woop Woop hed Q Sydney M 1 30 minutes Latitude 35 Nearest grid cell 34 9875 S Adelaide a ae N KOR AG i 1 12 hours Longitude 140 Nearest grid cell 140 0125 E gt art Wf NICAL WM 24 168 hours Melbourne 2013 MapData Services Ltd MDS PSMA Non Standard Durations i e Duration _ minutes F IFD Design Rainfall Depth mm Issued 29 July 2013 Rainfall depth for Durations Exceedance per Year EY and Annual Exceedance Probabilities AEP Duration 1EY 50 20 10 5 2 1 Table Chart 1 min 1 2 1 4 2 1 2 6 3 2 4 0 4 7 2 min 2 0 2 4 3 6 4 5 5 4 6 7 7 7 3 min 2 7 3 2 4 8 6 0 7 2 9 0 10 5 4 min a 3 9 5 8 io 8 8 11 1 12 9 5 min 3 8 4 5 6 7 8 4 10 2 12 9 15 0 10 min 5 6 6 6 10 0 12 5 15 3 19 3 22 7 15 min 6 8 8 0 12 1 15 2 18 6 23 5 27 6 30 min 9 0 10 6 16 0 20 1 24 5 30 9 36 3 1 hour 11 5 13 5 20 3 25 4 30 9 38 8 45 4 2 hour 14 2 16 7 25 0 ca He 37 9 47 5 mia 3 hour 16 1 18 8 28 0 35 0 42 5 22 3 62 4 6 hour 19 7 22 9 34 0 42 4 51 5 65 0 7
377. te The pismoidal formula is used to calculate volumes from surface areas Click Help for more details High Eary Discharge Figure A 28 Detention Basin Property Sheet The pipe property sheet is the same as the usual sheet shown in Figure A 15 while the overflow route has three pages describing the weir control of the high level outlet Figure A 29 and the geometric properties of the overflow route carrying flows from this Overflow Route OF 7 Basic Data Weir Data Cross Section Data How equation f Use weir equation C You specify H vs Q Figure A 29 Part of the Overflow Route Property Sheet for a Detention Basin When a run is made the results shown in the lower part of Figure A 27 are obtained and the reservoir routing calculations can be viewed from the pop up menu for the basin and the components connecting to it Figure A 30 shows routed hydrographs Basins can take many configurations and multiple high level outlets can be specified Reviewers should check that volumes in and out are consistent There can be differences between these due to infiltration to DRAINS cutting long drawn out outflows short and to basins being drawn down below the outlets at the start of a storm event Inspection of the hydrographs and other plots will enable reviewers to trace the behaviour of the detention basin Some issues that arise with basins are e Use of multiple low level outlets in parallel or series The DRAINS User Manua
378. te the flows from large floods such as a 100 year ARI flood The effects of detention basins and stream break outs or diversions can be assessed If you wish to combine the storage routing model results with the open channel hydraulic calculations available in DRAINS and or an ILSAX model this can be done to obtain more detailed results The open channel and ILSAX models can be set up in the usual way This integration of models should be useful in situations where there is interaction between a large watershed and a smaller urban catchment 4 3 7 Methods and Parameters Applied in DRAINS Usually designers must follow guidelines established by drainage consent authorities such as local councils or state road authorities supplemented by authoritative guides such as Australian Rainfall and Runoff the Queensland Urban Drainage Manual or AS NZS 3500 3 Nevertheless there will be many situations that are not covered completely in these sources It is the responsibility of the designer to choose how these situations are to be modelled and what parameters are to be applied DRAINS is a flexible tool that can be used with many different procedures and parameters and it is inappropriate for this manual to recommend specific methods or values or to specify how DRAINS should be applied in specific situations There is a discussion of alternative hydrological models in Appendix A 4 3 8 Choice of Model DRAINS offers a choice of hydrological and hydraul
379. terception en Channel Precipitation INTERCEPTIO STORE yee instantaneous es store IES Surface Runoff DEPRESSION mammi sige STORAGE Lo c fast H n Ponding So A n Infiltration N 2 Interflow i a SOIL MOISTURE STORE Percolation Groundwater GROUNDWATER Flow STORE very slow cms moro Deep Groundwater Flow p Streamflow or Runoff Figure 5 2 The Rainfall Runoff Process Models can be split into loss models and routing models as shown in Figure 5 3 Loss models represent hydrological processes such as interception depression storage evaporation and infiltration which prevent water from running off catchments immediately The most common types are a initial loss continuing loss models and b infiltration models using procedures such as Horton s equation Routing models allow for the distribution of rainfall across a catchment surface with some rainfall inputs being closer to the outlet than others and so spreading out the pattern of flow or hydrograph at the outlet They also account for storage effects on the catchment The main types are a time area routing b unit hydrographs c routing through artificial storages d kinematic wave routing and e unsteady flow hydraulic modelling across catchment surfaces The ILSAX hydrological model in DRAINS is a medium level rainfall runoff model that combines a Horton loss mode
380. tes derived using the methods from Australian Rainfall and Runoff 1987 and the Queensland Urban Drainage Manual 1992 While the ILSAX hydrological model in DRAINS should produce superior results to the rational method due to the testing and verification described in Section 5 3 3 and previous parts of this chapter it cannot provide similar peak flowrates to the rational method across a range of ARIs and storm durations The ERM employs the same time area routing procedure as the ILSAX model rather than assuming hydrograph shapes The loss model is different applying a continuing loss to all blocks of rainfall When the ERM was first released it assumed a constant continuing loss but inconsistencies were found when it was applied with storms of various durations The ERM assumes a continuing loss proportional to rainfall intensities The ERM requires the same input data as the ARR8 7 rational method Figure 1 39 but runs with rainfall patterns or hyetographs rather than intensities from an l F D relationship When applied with the design storm patterns from Australian Rainfall and Runoff 1987 Chapter 3 the peak flows obtained from a set of DRAINS User Manual 5 18 November 2014 design storms will differ from those given by the ARR87 rational method The synthetic storm option in the Rainfall Data property sheet Figure 2 73 has been provided to produce rainfall patterns that incorporate many blocks of rainfall of different average durations t
381. than the infiltration capacities at some times f Terie Tah Equation 5 6 c tih 1 aS g where f is the current infiltration capacity mm h and F is accumulated depth of infiltration mm The infiltration rate calculated from this is subtracted from the hyetograph or supply rate and should any water remain depression storage is subtracted Once the depression storage has been fully satisfied any excess over infiltration is assumed to be runoff The accumulated infiltration depth is increased by the amount assumed to be infiltrated For porous soils and light rainfalls it is quite possible that there will be zero runoff from pervious surfaces Malcolm Watson the developer of ILLUDAS SA suggested that an alternative method could be used which would not involve iterative calculations and this was incorporated into ILSAX This procedure described by Watson 1981b involved the division of the infiltration curve equation into diminishing and constant components fo fe e t and fs Watson used this concept in the following analysis The actual depth of infiltration AF over time step At is the lesser of At where is rainfall intensity and Fcap 1 e t i tt Fa fo At Equation 5 7 where F is the accumulated diminishing infiltration determined at each time step by _ AF Fy Fy AF cap fe At Equation 5 8 AF cap which apportions actual infiltration depths between dimi
382. the Whole Catchment of Rainfall Designstorm o o S oo o oo sme 3 3 3 33 na a2 mse a7 a7 a7 4 Ja 45hour 383 38 3 3 Jae Synthetic Fa 100 Year ARI Runoff Volumes from the Whole Catchment of Rainfall sme a7 a7 a7 a na 5 mnte s s se m 6 a a ee ee a a 45hour 39 39 39 s Jof Synthetic 0 8 A 4 5 Pipe Pit and Overflow Route Data Bases Hydrological Models When DRAINS runs it refers to data bases describing the Rainfall Data i hydrological model rainfall data and details of the pipe pit and overflow routes specified in the property sheets for various Select Major Storms components This information can be seen in the Viewer by Select Minor Storms a opening the property sheets for components b using the property balloons see Figure A 16 or c transferring data to Options a spreadsheet The transfer options are shown to the right Description The data bases can also be viewed using options from the Pipe Data Base Project menu Details are covered in the Manual and Help i system Pit Data Base Overflow Route Data Base Default Data Base DRAINS User Manual A 18 November 2014 Model Name Shepparton RORB Model Type Continuing Loss Type Cancel Pee aaa i Constant C RAFTS C Proportional WENM Hen Impervious Area Initial Loss mm Impervious Area Continuing Loss mmh Pervious Are
383. the same process this time for an ARI of 100 years and an intensity of 101 mm h Then click the OK button The next step is to select storms from the data base to be used for design and for analysis This is done using the Select Minor Storms option in the Project menu which opens the dialog box shown in Figure 1 11 Click the Selected storms button in the top left corner and then click the downwards arrow on the first drop down list box to show the names of the rainfall patterns in the data base For this example click on the 2 year ARI 25 minute pattern to select this storm as the one to be used to design the pipe system DRAINS User Manual 1 8 November 2014 Close this dialog box by clicking OK and then follow the same procedure with Select Major Storms to select the 100 year ARI 25 minute storm for major storm runs Rainfall Data Storm 1 4 Antecedent moisture condition 1 to 4 25 Annual Recurrence Interval years E E Storm duration mins 25 Raintall specified in Eo o o minute intervals Time mins Intensity rnrnh 00w50 amp Paste Intensity mm h Comments 5 10 15 Time mins __Add one ARRS storm Add Synthetic Storm _Add multiple ARRS storms Add aNew Stom Delete Current Storm C All storms Selected storms Run Use Storm Help 3 AR A 2 pear 25 minutes storm average 40 2 mmh one 1 ARRA 100 pear 25 minutes storm average 101 mmh Z
384. tic Storm Paste from Add multiple ARAG storms Add a New Storm Help Spreadsheet here hi Delete Curent Storm Figure 2 75 Observed Actual Rainfall Pattern from file Ilsax10 drn Whatever data are entered into the rainfall database they must be nominated as major or minor storms using the options shown in Figure 1 11 in order to run with the available options as set out in Section 3 4 There is the only way that rainfall date can be applied in runs There is no way of storing a specific set of rainfall patterns outside of the major minor setup 2 4 5 Pipe Data Base The Pipe Data Base property sheet shown in Figure 2 76 is opened by selecting the Pipe Data Base option in the Project menu This operates in two stages The first is to define a pipe type and to specify its name whether it is circular or rectangular its roughness according to the pipe friction formula set in the Options property sheet called from the Project menu and its minimum cover m The second stage is to provide data for specific pipe sizes in the property sheet shown to the right in Figure 2 76 For circular pipes the nominal diameter internal diameter 1 D and wall thickness must be supplied in mm For rectangular pipes the width m height m and wall thickness mm must be supplied The check box labelled Not available for selection in design runs allows you to omit pipe sizes that are considered too small or are unavailable If you wi
385. tion 5 3 Intermediate levels 3 18 Intermediate nodes 2 9 Intermediate points 2 11 Invert levels 4 14 Irregular open channel 2 29 bank 2 29 chainage 2 29 Junction 2 4 4 5 Kinematic wave 5 3 Kinematic wave equation 2 12 Kinematic wave routing 1 29 Lag time 1 15 2 14 Land use types 1 15 2 11 Links 2 3 Localised study requirements A 6 Long section display 2 11 Looped pipes 4 5 Loss model 5 9 Loss models 5 3 Main Window 1 5 Major minor design system 1 20 5 1 Manhole 2 4 Manning equation 5 33 Manning s coefficients 5 36 MapInfo file formats 5 44 MapInfo file imports 3 7 Maximum ponded volume 1 15 Menu 1 12 Menu bar 2 1 Menus 1 5 2 1 Merging DRAINS files 3 35 Merging files 3 9 MID MIF files 3 33 Mills pit coefficient equation 5 34 Mills revision of Ku coefficients 3 19 Misalignment of pits 1 12 Missouri Charts 5 34 Mixing of hydrological models 2 39 Modelling aspects 1 2 Modelling pits and pipes 4 6 Modified Puls method 5 36 Modified Rational Method 5 17 Moving storm 2 16 Multi channel 2 31 Multiple rainfall pattern entry 2 40 Names of components 1 15 New data bases 3 12 New South Wales Pits 5 23 Nodes 2 3 Non return valve 2 11 On grade pit 5 23 On site stormwater detention 2 38 On site stormwater detention system 4 13 Open channel cross section 2 29 Manning s roughness n 2 29 November 2014 Options 1 9 Ordinates 2 8 Orifice special for basins 2 27 Orific
386. tions These are covered by contraction and expansion losses typically 0 1 and 0 3 respectively These factors allow for energy losses due to changes in cross sections and velocities through these If the velocity increases or decreases between two cross sections the HGL is lowered by a coefficient multiplied by the difference in velocity heads at the two sections For example if the upper and lower sections are labelled 1 and 2 the losses for the two cases will be 2 2 Contraction coefficient vi Equation 5 25 2g 2g 2 2 Expansion coefficient vi vi Equation 5 26 2g 2g Table 5 23 taken from the HEC RAS Version 3 1 Hydraulic Reference Manual 2002 Chapter 3 gives values of coefficients Table 5 23 Contraction and Expansion Coefficients for Open Channel Flows Situation Contraction Coefficient Expansion Coefficient No transition Loss ae a Gradual Transitions Typical Bridge Sections Abrupt Transitions es O 5 8 Detention Basin Hydraulics 5 8 1 Routing DRAINS performs accurate reservoir routing calculations for detention storages employing the height storage outflow relationship and initial storage supplied by the user The method used is an extension of the Modified Puls Method based on the continuity equation applied over a time step At h a Oe 1 S l b ha QtQu Sin Si Equation 5 27 2 2 At Average of Inflow rates Average outflow Rate of change at the start of a period li
387. tive diameters of upstream and downstream pipes the angles of the pipes and the positions of their obverts and inverts the presence of benching in a pit the degree of submergence of the pit and the pit shape The Missouri Charts Sangster et al 1958 are the primary source of information on pressure changes with the paper by Hare 1983 being useful However there are many cases that are not covered by these and other references The Queensland Urban Drainage Manual Queensland Department of Natural Resources and Water 2008 provides a good coverage of available information on this topic together with a rather complex procedure for selecting pressure change coefficients using selected Missouri and Hare Charts There are theoretical relationships for pressure changes based on conservation of momentum calculations Hare and O Loughlin 1991 but these do not cover all cases 1 5 is given as a default value for k in the DRAINS Drainage Pit property sheet A review of pit pressure changes and head losses O Loughlin and Stack 2002 discussed possible algorithms or methods that might be used to determine pressure changes Two procedures the Mills equation and the QUDM Method described below have been implemented b Mills Equation In the DRAINS Run menu there is the option named Revise Pit Loss Coefficients This alters the coefficients using an adaptation of an approximate method devised by Mills Mills and O Loughlin 1982 98
388. tlet Where the basin is a ponding area in a street with a sag pit that acts as an unintended storage the above method can be used with the standard hydraulic model If the premium hydraulic model is available this pit should be modelled as a sag pit with a table of elevation area values describing the storage The fifth and last type of outlet is a None option If this is selected water can only leave the basin through a high level outlet to be described below and the outflows will not be affected by downstream hydraulic grade lines or backwater effects If a height outflow relationship is specified for a high level outlet the detention basin modelling will be carried out in the relatively simple way used in ILSAX rather than having HGLs projected upwards through the basin A new development is the provision of an in built infiltration calculation facility on the second page of the Detention Basin property sheet This appears as shown in Figure 2 37 Detention Basin ee Soe Data Initial Water Level Infiltration Data Perimeter 4 Floor is im 0 160 260 3 0 C mpemeable Walls are C mpemeable i Permeable Hydraulic Conductivity msec 5 006 E Faste Table Scientific Notation Figure 2 37 Infiltration Data Specification Allowance is made for a flat floor as provided in infiltration chambers and trenches and for walls through which infiltration will occur when the stored water level rises ab
389. tlet 2 W 7 Hi Dutletl Sy Pipe 3 Cat 5 Pes Pipe 5 a pa Outlet 3 4 nm j For Help press F1 Figure 1 28 Orange Drainage System Ready to Run with Property Balloon shown DRAINS Design amp complete DRAINS prepared a preliminary design and then Jaha attempted to refine this preliminary design but no pipes could be downsized Figure 1 29 Run Completion Message Figure 1 30 Multi Core Processing Query DRAINS User Manual 1 19 November 2014 If you agree DRAINS will display the Project Options property sheet Figure 1 12 in which you can click the box titled Enable multi core processing to reduce the processing time Whatever choice is made the analysis run proceeds and a report is displayed after it finishes as shown in Figure 1 31 X Orange2 DRAINS x File Edit Project View Draw Run Help ojew S o e lt H olv vu Oo ale AR amp R 2 year 25 minutes storm average 40 2 mmt v a Run Log for Orange2 run at 07 34 27 on 9 7 2014 No water upwelling from any pit Freeboard was adequate at all pits Flows were safe in all overflow routes For Help press F1 Figure 1 31 The Result of a Design Run and Minor Storm Analysis After you close this window you will see that the names of components have changed to coloured numbers as follows o the black numbers are the maximum flowrates from the sub catchments in
390. tmap Figure 3 2 shows a drawing created in AutoCAD LT representing a drainage system assumed to be at Brisbane E AutoCAD LI Brsbane dxt EA file Edit View Inset Format Jools Draw Dimension Modity Window Help Cae SUS RRP oe th BB ce oe a B a oe Sea uno 0 eer ByLeyer ByLeyor EvCokar BCT T 7 A V Oa Sea ony Alphabetic Categorized HI Coler E layer Layer BACKGROUND Linetype Linetype scale Lineweight Thickness Plot style Flot ste Alot style table Plot tabb attached to Mode Alot table type View Center X Conber Y enter Height width Mise UCS toon dn UCS icon at origin UES Narr Mod kM Model A Layou Command 2 1721 12 1226 ENAP GRID ORTHO POLAR OSMAP DWT MODEI Figure 3 2 Drawing of Drainage Network Information that is in this file can be imported by opening DRAINS and selecting Import a DXF File from the File menu You will be requested to nominate a file with a dxf suffix You will then see a dialog box that asks you to nominate the names of the layers on which pipes pits and background are located as shown in Figure 3 3 This is saved as a file Brisbane dxf Using the drop down list box you can select the appropriate layers Pits and pipes can be placed on the same layer if you wish Once layers are selected a number of information windows appear The first one shown in Figure 3 4 allows pipe lengths to be automatically scaled off the DXF drawing accordi
391. tn sideina aa 4 11 4 3 2 Designing Subdivision Piped Drainage SySteMs ccccccsecceessseeeeeeeeeeeeseeeeeeaeeeeeeeaeeeeeeas 4 11 4 3 3 Designing Infill Developments with On Site Stormwater Detention Systems 08 4 13 4 3 4 Analysing Established Drainage Systems cccccccccseeeeeeceeeeeeeeeeeeeseeeeeesaeeeeesaeeeeeesaeeeeeeas 4 14 4 9 9 ASSel Manageme Ni ainssi e subsmnenelvavess a a a a a 4 17 4 3 6 Performing Flood Studies with Storage Routing Models ccccecsseeeeeeseeeeeeeeeeeeeseeeeeens 4 18 4 3 7 Methods and Parameters Applied in DRAINS ccccccccccccseeccceeecceeceeeceesaeeesaeeeesseeeeeeas 4 19 A3 0 Choice Ol M del saci sees area aces ce tealeen ee Oew raced oni le de ees ae 4 19 5 TECHNICAL REFERENCE Sede HIMIFOGUCHOR i263 canna ave dcuseavedutcecueeutaue ON 9 1 DZ PECOCCESSONS icsicniceiiin ien nonen ainia E A E E E 3 1 cod AN oo ea a acl RoR E gO om 5 2 D8 TAVOPOIOGY cstisratorctouetousieuabanetinmtoratombdcstcsmbicnalastsesaeslcesniosksasoiestiesaeelasoioettesuiusah 5 2 sd GENE Ilepa a a e a a th vere saesostern tsennconsactus 5 2 53 2 The ILSAX Hydrol gi al M del s mrsinicdsi anta n a a a e 5 3 5 3 3 Testing and Verification of DRAINS ccccccccccceccccceeeeeeeeeeeeaeeeeeeseueeeeeeessaeeeeeeesasaeeeeeesaaaees 5 14 5 34 Rational Method Procedures ceceno ia a E aa AE Ra E 5 17 9 3 0 The Extended Rational Method rsrsr a a a 5 18 54 Storage ROUN Model Seesen N O 5 19
392. to apply different property sheets and relationships between model sub catchments and stream routing reaches These are described in Chapter 2 For stream channels routing can also be undertaken by methods such as the Muskingum Method lag and route methods Muskingum Cunge routing and hydraulic routing using methods such as kinematic wave calculations DRAINS employs the latter in RAFTS style stream routing reaches following a method given in Chapter 9 of Open Channel Hydraulics by F M Henderson 1966 DRAINS User Manual 5 21 November 2014 Ma Sub Catchment Rainfall Input Non Linear Routing Reach Junction Hydraulic Routing Reach sub Catchment Rainfall Input and Non Linear Routing Figure 5 18 Structure of Three Storage Routing Models 5 5 Pit Inlet Capacities 5 5 1 General The inlet capacity of pits is a vital factor in the modelling of piped stormwater drainage systems in major storm events separating surface overflows from underground pipe flows Pits can be distinguished by their form as grated pits kerb inlets or as combinations of these The latter two types are preferred in Australia Pits can also be distinguished by the situation in which they are applied On grade pits shown in Figure 5 19 are located on slopes in a channel such as a street gutter with water flowing to them and with any bypass flows escaping Sag pits are located in hollows or depression where the incoming flows for a pond over the p
393. to be inspected created or deleted while the drop down menu on the left allows alternative models to be selected The program will apply the selected model when the OK button is pressed If the Edit Default Model button is pressed the window shown in Figure A 9 appears displaying the model characteristics This comes from the model in file Gymea Piped Drain Model drn using the hydrological model in the ILSAX program from which DRAINS was developed The parameters shown are a depression storages which represent depths of water retained in puddles over the whole sub catchment area and b the soil type which relates to sets of numbers that control the infiltration rate of water into the soil The depression storages apply to the three types of land use used in ILSAX models a paved representing the impervious areas directly connected to a drainage system b supplementary representing impervious areas that are not directly connected where runoff must flow over an infiltrating surface before reaching the drainage system and c grassed areas representing pervious surfaces of various kinds Typical values for depression storages are 1 mm for paved and supplementary impervious surfaces and 5 mm for grassed surfaces The higher these storages are the lower the resulting runoff flowrates will be Values exceeding 2 mm for impervious surfaces and 10 mm for grassed surfaces should be justified Default Model for Design and Analysis Ru
394. torm Animation from Pit 1 to Outlet ARER 100 pear 25 minutes storm average 101 vain Fone 2 T 21 minutes Play Pause Restart Faster Slower Close Figure 1 47 Animation of Flow Along Main Line of Orange System in a Major Storm 1 2 4 Running Storage Routing Models Storage routing models can be implemented using many of the same features and processes used with the ILSAX and rational method programs To illustrate this consider the RAFTS Model shown in Figure 1 48 modelling a hypothetical creek at Shepparton Victoria This rural catchment has been divided into four sub areas and a RAFTS model has been superimposed on this The four sub catchments shown by the symbol E are sites where conversions from rainfall to runoff and routing processes occur Routing can also occur if required in the stream routing reaches shown dashed DRAINS User Manual 1 28 November 2014 3 Shepparton RAFTS Rural drn DRAINS Loli File Edit Project View Draw Run Help Dist S oleam ovu a ale Sub Catchment Data i R each A Sub catchment name Catal Sub catchment area ha 476 Impervious 4rea of total 0 Hydrological Model eer ee Sub Catchment Slope 6 CatC E Ai You specify Manning s n 0 025 Node cQ CatB to wer Shepparton RAFTS mE DiodeB a Cancel Reach By Cat D Notes S Customise Storms jane Dutt Ream ou Help 4 ul p Press F1 for help Figure 1
395. ts When installed on a PC using Microsoft Windows the program resides in the folder C Program Files Drains Program along with related files It also places a default data base file named Drains db1 inC ProgramData Drains to meet Microsoft Vista requirements At present the Drains exe file is about 4 Mb in size and is accompanied by a HTML Help file of 4 Mb To run with capabilities beyond those of the demonstration version a hardware lock or dongle must be inserted into a USB port or with earlier types the 25 pin printer port of the PC DRAINS can be installed and run on any PC or server system to which a hardware lock has been attached The hardware lock will control the number of conduits that can be modelled 20 50 and unlimited and whether rational method storage routing GIS modelling or premium hydraulic modelling facilities are implemented The DRAINS Viewer described in Appendix A is a separate program but operates in the same way as DRAINS Both programs can be opened at the same time The Viewer is installed from a self extracting file and users can navigate through DRAINS models property sheets and outputs of results in the same way as DRAINS However they cannot modify or run models There is no size limitation on the Viewer and it can be freely distributed To read the latest DRAINS models the Viewer needs to be periodically updated To obtain the latest version contact Bob Stack or Geoffrey O Loughlin at the numbers g
396. u m s 4 36 Upstream water level m at this flow 700 12 Downstream water level m at this flaw 700 0 Figure 2 57 Second Page of Bridge Property Sheet Top Part DRAINS User Manual 2 36 November 2014 This information might be obtained by running the DRAINS model without a bridge to estimate the maximum flowrate and inserting the bridge later The upstream and downstream water levels can be estimated from the level without the bridge making the upstream level higher and the downstream level lower The differences might also be determined from relationships from texts or manuals 2 3 17 Combining Components Some arrangements of the components described in the preceding sections cannot be modelled because they are not logical or they create computational difficulties Table 2 2 describes the possible connections between nodes and links noting those that cannot be made The footnotes provide suggestions as to how you can get around some of these limitations Experienced modellers can use dummy components to model complex situations Table 2 2 Allowable Connections between DRAINS Nodes and Links Link into Node from Upstream U S or Downstream D S Node Prismatic Irregular Multi Overflow Channel Channel channel Route Simple U S yes U S yes U S yes U S yes U S yes Node D S yes D S yes D S yes D S yes D S maybe Detention U S yes U S yes U S yes U S yes U S yes Basin D S yes D S no D S no
397. uitable studies to calibrate the model in rural conditions rather than any defect in the model itself b Time Area Routing The basis of the ILSAX model s hydrograph generation is the time area method illustrated in Figure 5 5 which convolves the rainfall hyetograph with a time area diagram in a similar manner to unit hydrograph calculations A time of entry or time of concentration must be determined for a drained area using methods discussed later in Section d A total Contributing Area ha gt at att At lt TIME AREA DIAGRAM intensity mm h RAINFALL HYETOGRAPH Q 0 Q4 C Aih Q5 C Ailo Asli Q3 C Ails A2l2 Aaly Q4 C Aylq Aalst Azle Flowrate Qs C A l5 Aalat Agls m3 s Qs C Aals Agia Q7 C Agls Qs 0 Figure 5 5 Time Area Calculations Assume that the rainfall hyetograph has had losses removed and so represents rainfall excess and that the hyetograph is divided into time steps of At The time area diagram a plot of the catchment area contributing after a given number of time steps is divided in the same intervals This diagram can be visualised by drawing isochrones or lines of equal time of travel to the catchment outlet For times greater than the time of concentration the contributing area equals the total area of the catchment When a storm commences on a catchment that has a time of entry of 5At the initial flow Qo is zero After one time step
398. ular Cross Sections These depend on the threshold level TH which is usually the invert level at the upstream end of the outlet pipe or culvert m AHD and pipe diameter D m For HW TH lt 0 8 D the flowrate for Inlet Control is Q Ne 1 50 S 40 HW TH D Equation 5 29 inlet control unsubmerged inlet Henderson 1966 For 0 8 D lt HW TH lt 1 2 D Q N 1 38 S 40 HW TH D _ Equation 5 30 inlet control unsubmerged inlet Henderson 1966 and For HW TH gt 1 2 D Q N 1 62 HW TH D _ Equation 5 31 inlet control submerged inlet Boyd 1986 The flowrate for Outlet Control is Q Ne D HW TW 2g ke k Factor 1 __ Equation 5 32 outlet control full pipe flow The outflow rate Q m s corresponding to level in the basin or headwater level HW m AHD is the lesser of the calculated Q and Q values Parameters used in the four equations are N is the number of parallel conduits L and S are the conduit length m and slope g is acceleration due to gravity taken as 9 80 mis TW is the higher of a the tailwater level downstream of the outlet m AHD and b a level half way between the outlet obvert level equal to TH Se Le D and the level of the critical depth of the flow at the pipe outlet calculated from and de D Coca 0 510 for Ge lt 0 82 Equation 5 34 3 005 D D
399. ulic Conductivity Sandy soil gt 5x10 mis Sandy clay between 1 x 10 and 5 x 10 m s Medium clay and some rock between 1 x 10 and 1 x 10 m s Heavy clay between 1 x 10 and 1 x 10 m s Constructed clay lt 1x10 m s DRAINS User Manual 5 42 November 2014 5 9 Culvert and Bridge Hydraulics 5 9 1 Culverts There are two meanings to the word culvert The first is a long pipe the second is a pipe usually short constructed to allow flows in streams and artificial open channels to pass under road and railway embankments The culvert component in DRAINS models the latter case The first type of conduit should be modelled as a channel or if storage and overflows are important as a detention basin Culverts convey flows in pipes or rectangular conduits that through road embankments usually obstructing flows by reducing the available waterway areas Upstream water levels are raised creating a headwater level higher than the water levels occurring under unobstructed flows Downstream levels are lower since flow emerges rapidly from the culvert creating supercritical flow conditions until a hydraulic jump occurs Several procedures are available for the design of culverts and analysis of their behaviour In DRAINS the sets of equations presented by Henderson 1966 and Boyd 1986 given in Section 5 7 are used to determine the headwater levels occurring with a given flowrate and downstream tailwater level at each calculation time step
400. used on Housing 1987 accessways RM7 Pit Sutherland 0 85 1 2 1 8 0 85 1 2 1 8 2 4 0 9 m x 0 5 m No grate or Durham Cast iron Shire Council 2 4 and 3 0m and 3 0 m wide by m high grate 1992 lintel 0 15 m high The set of pits shown in Figure 5 21 was the basis of both the RMS RTA and Hornsby Council relationships which have different forms The former allows for longitudinal slopes while the latter provides a single relationship for all slopes Relationships developed for Australian Capital Territory are detailed in Table 5 14 DRAINS User Manual 5 24 November 2014 Pit Type SA1 1m kerb inlet with 25 mm depression cast iron grating A 190 450 M 4gom Pit Type SA2 E _s LL Pit Type SA5 m extended kerb inlet with 25 mm depression cast iron grating A 190 NSW Road and Traffic Authority Kerb Inlets with Depressed Grates tested in 1979 Figure 5 21 Type SA1 SA2 and SA5 Pits tested for the NSW Department of Main Roads Table 5 14 ACT Pits Source ACT Government Urban Stormwater Standard Engineering Practices Edition 1 www act gov au storm Pit Size Kerb Inlet Grate Size Comments Type Dimensions Sump QS 0 6 m long Only for sags in three types of gutters Sump 1 3 m long In three types of gutters KG MLBK amp MKG Victorian relationships obtained by extrapolating the curves given in the VicRoads Road Design Guidelines Part 7 Drainage 1995 are available for the pits
401. vanced Road Design Link The Advanced Road Design ARD program is used inside Autodesk Civil 3D It has purpose built tools for creating drainage network geometry and assigning the catchment overflow route surface profile geometry information required by DRAINS ARD was developed by Peter Bloomfield and CADApps www cadapps com au www civilsurveysolutions com au This transfer procedure works when DRAINS has ILSAX or ERM specified but not for the rational method When this is specified as the hydrological model the links to ARD in the File menu mentioned below do not appear To make a transfer from the ARD Drainage menu use the command Drainage gt Data Exchange gt Write to Drains With Civil 3D the data is written to the Drains n mdb file in the DrawingName_Data AdvRoads directory under the directory holding the drawing file In DRAINS use the File gt Import gt Import Advanced Road Design file command to import the data After making a run in DRAINS use the File Export gt Advanced Road Design file command DRAINS User Manual 3 11 November 2014 to export the data This command writes the Design data back to the Advanced Road Design data file from where it is exported back to the Advanced Road Design data file for plotting with the Drainage gt Data Exchange gt Read in Drains data command For further details view the educational video at www civilsurveysolutions com au Advanced Road Design wt You can view Web
402. verflow Route Data Bases New data bases can be established using the Default Data Base Option in the Project menu This opens the dialog box shown in Figure 3 17 from which a base can be selected from the db1 files stored inthe C Program Files Drains Progranm folder This is followed by a warning indicating that the default db1 file Drains db1 will be overwritten Note that this can only be done with a DRAINS file that has an empty main window Once components are entered the only way to add pipe or pit types is by hand In addition it is not possible to delete pipe and pit types in this situation though their characteristics can be edited and changed db1 files are related to the new pit data bases and db files to the older system described in Section 2 4 6 An additional feature implemented through the Import gt DRAINS Database DB1 File option in the File menu can be used to add extra pipe pit and overflow route types to a data base as described in Section 2 4 5 DRAINS User Manual 3 12 November 2014 Select Default Data Base for New Projects NSW Pits June 2008 db1 MS Pits June 2008 db1 Queensland Pits June 2008 db1 Help South Australian Pits Oec h db South Australian Pits July 2008 db Victorian Pits June 2008 db1 only used in diferent VWiA Pits Movember 2006 db1 ou can edit or change the default data base at any later time Figure 3 17 Default Data Base Dialog Box 3 3 Display Options
403. vious Percentage of area 7 33 67 Time of Concentration mina E 13 Figure 1 42 Sub Catchment Data Property Sheet with Rational Method DRAINS User Manual 1 25 November 2014 Table 1 5 Rational Method Sub Catchments Pervious Pervious Pervious i c te i C10 a Cat 1 Pit 1 0 125 67 0 26 3 Orange2 Rational Method DRAINS XS File Edit Proje View Draw Run Help Di aj ojejajajm elve 9 ale 0 008 Run Log for Orange2 run at 07 52 42 on 9 7 2014 28 ee Seen No water upwelling from any pit Freeboard was adequate at all pits 2 08 upwelling from any pi equa pits 0 052 To see more detaile a sults select the Edit Copy Results to Spreadsheet menu item and paste pa Pasah ce 0 Flows were safe do erflow routes Results of Analysis pp p Figure 1 43 Results of Rational Method Design Run DRAINS also provides an Extended Rational Method ERM model using many of the assumptions in the Australian Rainfall and Runoff version of the rational method This can use design storm patterns like those employed by the ILSAX hydrological model The method is described fully in Section 5 3 5 1 2 3 Running the Premium Hydraulic Model The unsteady flow model used in the standard hydraulic model makes allowance for the storage effects of flows along pipes and open channels The premium model extends this to overflow routes allowing accurate determination of water
404. w no sidelines no grate inflow On this property sheet there is also a check box with the label Pit has bolt down impermeable lid that allows pits to be sealed and the HGL may rise above the surface A sealed pit cannot accept flows at the surface and cannot overflow In the sheet there is also provision for specifying blocking factors default values of which can be set in the Options property sheet opened from the Project menu as shown in Figure 1 12 The inlet capacity calculated from the relationship obtained from the Pit Data Base is multiplied by 1 minus the blocking factor Thus a factor of 0 2 will reduce the inlet capacity or capture rate by 20 More restrictive blocking factors are usually applied for sag pits than for on grade pits Values of 0 5 for sag pits and 0 2 for on grade pits are typically used though the latter in particular is questionable On the second page with the tag QUDM shown in Figure 2 4 you can nominate whether the pit is aligned or misaligned and to provide the pit wall width in mm at the location of the outlet pipe This is only required if you wish to apply the QUDM Chart procedure to define pit pressure change coefficients DRAINS User Manual 2 5 November 2014 Drainage Pit Pit Properties QUDM wipe or the grate if there is no upstream pipe aligned Information for QUDM determination of pit Misaligned pressure coefficients Pit intemal width mm for Chart Figure 2 4 Dr
405. wa Te ue Tr we a PIPE DETAILS Name From To Length U SIL D S IL Slope Type Dia I D Rough Pipels No Pipes Chg From AtChg Chg m m m mm mm m Pipe A 1 PitA 1 Pit A 2 17 4 30 614 30 414 1 15 Concrete 1200 1200 0 013 New 1 PitA 1 0 Pipe A 2 PitA 2 Pit A 3 76 1 30 244 26 544 2 1 Concrete 1350 1370 0 013 New 1 Pit A 2 0 Pipe A 3 PItA 3 Outlet 37 7 28 184 27 434 1 99 Concrete 1800 1800 0 013 New 1 Pit A 3 0 Pipe B 1 PitB 1 Pit A 3 12 8 29 145 28 945 1 56 Concrete 1050 1070 0 013 New 1 Pit B 1 0 Pipe C 1 PitC 1 Pit A 3 29 555 29 38 2 19 Concrete 600 600 0 013 New 1 Pit C 1 0 Figure A 17 Part of Spreadsheet Output DRAINS User Manual A 21 November 2014 Pipe A 2 Maximum Flow and HGLs for the Selected AR G amp A 100 pear 25 minutes storm average 133 mmh one 1 ha 0 75m Cover D La i m ee Length 76 1 metres Diameter 450 mm Pipe Slope 1 91 Omak 0 323 cums Wmas 2 76 to 2 47 mis Figure A 18 Long Section Plot for a Pipe Showing Pipe and Flow Characteristics Long Section Drawing Preview Export DXF Long Section Step 1 Select a route Add a Long Section From pit Pit 4 1 To pit or node Outlet Cancel exporting any ro relative sizes nas 5 Hea F brani Pantoeyy Lard tava O E Ei a F 1 vaUEF my _ Save as DF Print Customise Close Help Figure A 19 Pipeline Long Section Plot displayed prior to Transfer
406. water levels Because it allows for stored surface water at pits and in along flow paths it usually specifies lower flowrates and water levels than the standard model Thus the standard model can be considered to give results that are conservatively high Table A 14 Hydraulic Models applicable to Open Channels and Overflow Routes Estimation of flow capacities and velocities for a given Manual calculations using Manning s flow depth channel full levels equation or a similar relationship Normal depth calculations estimating flow depths Manual or spreadsheet calculations or velocities and other characteristics for a given flowrate simple models in programs such as involving simple iterative procedures HEC RAS or DRAINS overflow routes only in basic hydraulic model 1 dimensional 1D steady water surface profile HEC RAS DRAINS basic hydraulic calculations sub critical supercritical or mixed both model now obsolete 1 D quasi unsteady water surface profile a series of DRAINS basic hydraulics model steady state calculations obsolete 1 D unsteady water surface profile calculations RUBICON MIKE11 xoswmm HEC RAS DRAINS Quasi 2 dimensional surface flow models created by CELLS obsolete MIKE11 xoswmm linking 1 D unsteady flows in a network with suitable DRAINS overflow controls 2 dimensional 2 D surface flow models RMA 2 using finite elements MIKE 21 Sobek and TUFLOW finite differences finite volume Inf
407. with Entry Gully Type Gully allowance for deflectors TEN to DEN Main Roads Gully Single Pit 0 92 m long x On grade and sag TGT to DGT 0 425 m wide Main Roads Single none As above On grade and sag assumed Normal Catchpit Grate to be used in swales Main Roads High Single As above As above Flow Catchpit Grate 150 mm above surface DRAINS User Manual 5 27 November 2014 Table 5 19 Tasmanian Pits Developed from government drawings and Generic Spreadsheet using HEC 22 procedures No measured data Kerb Inlet Dimensions Pit Type Size Grate Size Comments Single grated 0 9 m wide 0 9 x 0 45 m At some slopes the double Grated deflector 1 865 m wide 0 9 x 0 45 m grate pit has the highest deflector capacity at other grades it 19x0 45m is the grated deflector pit Double grated 1 9 m wide City of Double grated 1 68 m wide 0 89 x 0 40 m Devonport extended kerb inlet Dept of Mountable kerb 1 0 m wide None Infrastructure 1 8 m wide 0 9 x 0 35 m Energy amp deflector Resources 0 9 m wide 0 9 x 0 35 me Asabowe Asaboe V Channel none 0 98mx0 64m 5 5 3 US Federal Highway Administration HEC22 Procedures The Hydraulic Engineering Circular No 22 of the US Federal Highway Administration 2009 available from www fhwa dot gov bridge hyd htm contains the only general methodology available for defining inlet capacities for all kinds of rectangular pit It is applied as a series of equations
408. xf Poly ial Oldtown Base dxf Mull Oldtown Base dxf Poly oT Ives St Location 340 582 166 532 Unknown Uni a EA If A Commercial ren Identified 1 feature ren if E 0 100 m O O O E 27 m anjana gt 3 A O7 Aw X Ana fro J BZU A e aa a Sw Drawing Y k 726 459 389 898 Unknown Units _ Figure 3 7 The Oldtown Example in ArcMap To make the transfer you must place all files to be transferred into the same Windows folder set up a DRAINS model with the ILSAX hydrological model and pit and pipe data bases that you require and then use the File gt Import gt ESRI Shapefiles option which will display the message in Figure 3 9 After entering Yes you must select one of the ESRI files to be transferred as shown in Figure 3 10 The transfer will then take place and the pits and pipes will come into view as shown in Figure 3 11 DRAINS User Manual 35 November 2014 Wy Atiibutes of Oldtown Nie a FAMILY SIZE PONDINGVOL KU SURFACEEL PONDDEPTH BASEFLOW BLOCKFACTR BOLTDNLID Eo stepe T mame oranso P orom rear S n Pom PRA2 2 Point PBa 2 Point PRAS a Point Pas Pom Pras 6l Fom Prae 7 Point PRAT eom Peas e pom Peas io Point PRA 10 i Point PRAIS J Pont pran 72 Point Pioa ie Point Pec 15 Point Pees re Point Pez or Point Pact re Poin
409. ying intensities across a catchment with the same storm pattern can be modelled by setting up a rainfall pattern in the Storm Data Base for each intensity used and selecting appropriate ones for each sub catchment A simpler alternative is to set a suitable multiplier for each sub catchment in the property sheet shown in Figure 2 24 e Varying storm patterns across a catchment can be modelled in the same way by selecting patterns from the data base that apply to each sub catchment and applying multipliers if necessary e Amoving storm can be described by specifying different lag times for the start of the storm for each sub catchment DRAINS User Manual 2 16 November 2014 These options allow you to specify a different rainfall pattern and intensity at every sub catchment in a drainage network They can be used to model climate change effects 2 3 6 Overflow Routes a General These paths define the routes taken by stormwater flows that bypass on grade pits and or overflow from pressurised pipe systems DRAINS uses this information to calculate flow characteristics along the routes The property sheet takes different forms depending on the hydraulic model being enabled Three different routing processes may be involved a translation shifting of a hydrograph by a time lag without changing its shape employed in the standard and obsolete basic hydraulic calculations b kinematic wave calculations employed in stream routing channels w
410. you must enter e the channel name total length and chainages or lengths of reaches along a stream a set of X Y coordinates m that define the cross section with the X datum being at an arbitrary point on the left bank of a channel and the Y datum being Australian Height Datum AHD or some other standard datum as shown in Figure 2 45 e distances from the upstream node m and Manning s roughnesses for the left overbank main channel and right overbank areas e coordinate locations of the left and right banks m and expansion and contraction coefficients dimensionless Various features assist the entry of cross sections Sections can be copied and pasted The top section of a reach must be the same as the bottom section of the reach above it If reaches are entered in a downwards direction DRAINS automatically enters data from the previous reach Sections can be viewed and checked using the View Cross Sections and View maximum water level profile options in the pop up menu for an irregular channel component as shown in Figure 2 46 DRAINS User Manual 2 29 November 2014 Total length m from upstream node to downstream node 40 Mannings n Values Cross Section Coordinates ance 0 020 2 m AL rm D 00 5 Scale off Length 699 5 699 2 Add Section LOE Channel 0 030 FOR 0 035 Main Channel Lett bank amp coordinate Right bank amp coordinate oe Delete Sechon B98 7 699 1 699 5 z as 00E aste
411. ype Hydrological Model Model name Orange Soils Faved imperious area depression storage mm supplementary area depression storage mmj Grassed perious area depression storage mm soll Type fe Normal ta 4 J You specify Figure 1 6 ILSAX Type Hydrological Model Property Sheet Top Portion Enter the name and numbers shown These will be explained later but if you require an immediate explanation press the Help button to open the Help screen shown in Figure 1 7 DRAINS Help arim e aiy Hide Back Print Options ILSAX hydrological model Type in the keyword to find ILSAX hydrological mode The ILSAX loss and routing models were taken from the programs from which ILSAX was developed particularly ILLUDAS and ILLUDAS SA All use a loss model involving depression storages and the Horton Term infiltration model for pervious areas and the time area method as a routing model to convert rainfall Hydraulic grade line hyetographs to runoff hydrographs Hydrograph Harama ma Terstriep and Stall the developers of ILLUDAS created a loss procedure for pervious areas using the U S id numbers in spreadsheet Soil Conservation Service soil classifications Malcolm Watson developer of ILLUDAS SA developed an IFD intertwined loss and routing model that adapted the time area method to allow the water running from one a strip of catchment onto another to be infiltrated Rainfall ILSAX hydrological model property she

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