Erosion-3D - GeoGnostics
Contents
1. DEM You can change the density of the drainage network by changing the CSA value in Relief Hydro Drainage network Finally select View Close graphics or press the x button The program now computes the drainage paths If no problems occurred a message box appears Normal termination 1 3 2 Creating soil parameters files from raster files For each parameter a raster file is required This file contains data within a rectangular boundary All input files must have the same number of rows and columns as well as the same grid size and corner coordinates The files can have different formats Arc Info Grass Idrisi and Surfer The grain size distribution is treated the following way For each of the 9 grain size classes an input file must exist The sum of all 9 classes must be 100 in each element The percentage values are stored as integers All files have the same file name The suffix determines the grain size class The suffix 1 means fine clay the file with the suffix 9 contains the coarse sand fraction In the file selection window the file with suffix 1 is chosen The program will load the other fraction files automatically Example Open the Soil Landuse Create Soil data set command The dialog window Soil input files opens Press the Erodibility button If needed select the drive and directory where the sample files are stored samples indata soil_landuse soil_cr All sample files provided on the installation CD are2. t ha Ga lt 250 F 250 25 25 2 5 2 5 0 01 _ 0 01 0 01 10 01 2 5 2 5 25 E 25 250 E gt 250 __ No Data Figure 15 Sediment budget for the sample data The net erosion for the watershed is 5 7 t ha 23 Note The project can also be run with the project file s7_snow7prj par which is located in the samples directory 24 1 7 Check dam model tutorial 1 7 1 Preparation of DEM The following example shows one way to create a DEM with check dam information using ESRI s Arc Info software A check dam line was digitised in an external CAD program The DXF file is imported Ares dxtare damlwdxt daml 40 16 The line topology is created with Are paila dam Line Then the line is converted to a grid Arc linegrid daml damlg dxf elevation The altitude information is stored in dxf elevation The grid dimensions must be identical to the DEM Arc linegrid daml damlgl dxf elevation Converting arcs from daml to grid damlgl Cell Size square cell 10 Convert the Entire Coverage Y N n Grid Origin x yhe 4500099596023399 Grid Size nrows ncolumns 146 108 Enter background value NODATA ZERO Number of Rows 146 Number of Columns 108 The outlet from the impoundment which is a channel element must not be changed Therefore this cell is assigned the NODATA value Grid dirioplay 9992 Grid mape damig Grid gridpaint damig Grid cellvalue damig Grid cellvalue dam
3. ASCII file if necessary An adequate soil parameter data set must be available for each polygon or landuse class e g forest Single parameters are stored in columns and they are delimited by commas The first row may be altered however it may not be deleted The first column of the data set is a consecutive numbering followed by single parameters in the next columns The last column is the alphanumerical name of the parameter data set This name enables a linkage of the parameter data set to a lookup table 9 containing areas of the grid file This linkage file contains a numerical ID for a single area in the first column and the related alohanumerical name of the parameter data set in the second column The columns are delimited by a comma The advantage of this procedure is Land use can be altered easily without altering the ID of the vector file or the ID of the parameter data sets Soil input files File Name Hows Columns Cell size Seno landusel asc 146 105 10 File Hame Records Soil data file jun cs 0 Lookup bt 0 Create output data set Cancel Figure 7 The Create soil file Dialog window Example Select Soil landuse Create RDB soil data set Press the button Raster file In the open window select the file landuse1 asc from the samples indata soil_landuse soil_rdb directory The file type is Arc Info Ascii Leave the dialog by pressing Ok Press now Soil data file and select juni csv Select looku
4. current soil conditions and stages of crop growth of that date Repeating the simulation of this reference year ten times gives an idea about the sediment budget and the change in topography within a 10 year period Example In the Long term options tab enter the values like in example 1 Choose Simulation Long term simulation Check the Long term simulation on off checkbox Enter the following values in the Long term options tab Iterations 10 Result smooth passes 1 Result smooth radius 1 Save result at the end of long term simulation 16 Modify relief checked yes Relief radius 10 Relief smooth passes 0 Relief smooth radius 1 Save relief at the end of long term simulation Move to the Sequence files tab Right click into the Relief Hydro edit field and choose Add data set Select the relief data set samples outdatarelief relief_t Next go to the first line of the soil and precipitation input grid Right click into the Soil edit field and choose Add data set file Select a soil data set Start with samples outdata soi 0506 where 05 month and 06 day Right click into the Precipitation edit field and choose Add data set file Select a corresponding precipitation file Start with samples indata meteo e3d32 refyear O_ _0506 csv Either press the enter key or the Add event button Continue with the other 21 dates lf you want to skip this procedure you can press the Load list button on the Sequence fil
5. result 0604 rs If you want to display the sediment budget results in the traditional Erosion 3D colors and value classes choose View Edit legend Press the Load button and select the file e3d eg in the program directory and press Apply To find out how much sediment has left the watershed select View View options then on the Flow routing tab sheet check Show drainage network In the tool bar press the Identify tool and locate the blue channel grid cell in the south west where the channel leaves the watershed Select the cell with the center of the cross hair cursor The Data for selected cell dialog opens In the upslope data section channel flow you will find the value for the sediment volume As the unit of measurement is mass unit width you need to multiply this 12 value with the cell width 10m so the total sediment output from the watershed is 2693 kg 0 038 t ha This sediment mass consists of 90 of material of the silt size fraction The same method applies for the runoff which is 29 92 m Note The project can also be run with the project file 0604 par which is located in the samples directory 13 1 5 Long term simulation tutorial The long term simulation model performs the simulation of a sequence of events and or the reiteration of a Sequence or single events 1 5 1 Example 1 Long term simulation based on a single event A summer rainstorm event is to be simulated fo
6. stage and area remain constant Unlike the first version with evaporation and infiltration the sediment concentration decreases in time The settling of the clay particles is undisturbed und is reflected in a smoother deposition curve 29 10000 1000 100 m Stage m Volume m 3 Imp Area m 2 cum Channel flow in m3 4 cum Channel flow out m 3 1000 2000 3000 4000 5000 6000 7000 Discharge Im 0 1 0 01 0 001 Interval 10 min Figure 20 Hydrology of the sample data without infiltration and evaporation 1000000 100000 10000 1000 Deposition Clay kg 100 Deposition Silt kg Deposition Sand kg Sed Conc kg m 43 10 Imp volume m 43 Sed volume kg 1 I I I I 2000 3000 4000 5000 0 1 0 01 0 001 Interval 10min Figure 21 Sedimentation behavior of the impoundment without infiltration and evaporation 30 1 7 3 Handling two or more impoundments The procedure for the determination of the pour points is the same as described above After you have finished entering the data for the first pour point close the Impoundment data dialog and select the next pour point with the pour point tool The impoundment ID is incremented automatically in the Impoundment data dialog Close the map window by selecting View Close graphics or by pressing the amp tool bar button The pour po
7. tool bar button The pour point options are written to the relief data set In the check dam options switch on the model with the Run model checkbox Also check Save stage volume list Save hydro data Save sediment data Do not check Save lake cover as this option will use a large amount of disk space Now select the check dam relief data set with the menu item Relief Hydro Select relief data set Example Select the relief parameter data set samples outdata checkdam cd1 rel Choose the Soil Landuse Select soil data set command to open the soil parameter data set Select the soil parameters data set samples outdata soil 0604 The precipitation parameters are selected in the dialog box that is opened with Meteo Precipitation Zones Select the precipitation parameters file samples indata meteo e3d32 cdrain extr100 csv This event is a heavy rainstorm with a recurrence interval of 100 years The total sum is 73 4 mm during two hours with a maximum intensity of 2 8 mm min The command Simulation Run starts the computation The file type box lets you choose between ASCII and binary format For the example select Erosion 3D relief data set Ascii A Save result data set dialog opens First you should create a new data set Press the New folder button and enter a name for the new data set e g checkdam1 A new directory is created Finally press the Save button 26 After the calculation is finished you will find two files in the resu
8. Arc Info Ascii files Therefore set the Arc Info Ascii file type Choose the file ero asc Close the dialog with Ok The selected filename and the file characteristics are displayed Choose all required files successively according to the same principle until all Name fields contain file names A file with the name texture1 asc must be selected in the case of a grain sizes file Continue with the other files see Table 1 Parameter File name Erodibility ero asc Roughness rough asc Cover cover aSc Particle texture1 asc Bulk density density asc Organic corg asc Moisture initmoist asc Skin factor corr asc Table 1 Soil input files Soil input files Fale eis alae e Erodibility era ast 146 108 10 Roughness rough asc 146 105 10 Cower COVE AZC 146 108 10 Sheet textured asc 146 105 10 Bulk density density asc 146 108 10 Corg cong atc 146 108 10 moisture initmorst asc 146 108 10 Con asc 146 108 10 Create output data set Cancel Figure 5 The dialog window Soil input files Finally press the Create output data set button The File format dialog opens There you can choose between ASCII and binary format For the example select Erosion 3D soil data set Ascii Press ok The Save Soil Data set dialog opens First you should create a new data set Press the New folder button and enter a name for the new data set e g samples outdata soil Soil_cr A new directory i
9. Erosion Deposition t ha a lt 250 F 250 25 25 2 5 2 5 0 01 _ 0 01 0 01 0 01 2 5 E 2 5 25 E 25 250 E gt 250 __ No Data Figure 12 Total sediment budget after long term simulation Note The project can also be run with the project file ts_ref22 10 par which is located in the samples directory 18 1 5 2 1 Displaying the modified DEM You can visualize the change in elevation as follows First you need to calculate the elevation difference by subtracting the old dem from the new dem Select File Grid tools Grid calculator Use relief lts dem_re asc for Ingrid1 and relief dem_re asc for Ingrid2 Next set the Outgrid name dem_diff asc then press Evaluate The output grid is created You can display the result with View View grid file dem_dif asc 1 5 2 2 Querying the Its result grids Choose the grid ts_ch_sum_sedvol asc with View View grid file Select the Identify tool from the toolbar Click on the grid cell at column 36 row 131 with the crosshair cursor A dialog box appears that shows the grid value for the cell The grid value for the ts_ch_sum_sedvol asc represents the cumulative sediment volume in channel over all events and iterations in kg m Multiply this value by the cell size to obtain the total sediment loss in kg 19 1 6 Snow model tutorial The snow model is mainly controlled with the snow model dialog box
10. Erosion 3D Ver 3 0 User manual Samples GeoGnostics Software This book whether the whole or part is subject to copyright Any duplication reprinting translation use of illustrations reproduction on microfilms and storage in data bases is illegal without permission by the author Violations are liable for prosecution under the German Copyright Law Erosion 3D Ver 3 0 User manual Samples Ver 3 0 Revision 0 52 12 03 2003 2003 Michael von Werner Berlin Contents 1 sampe DIO SCE is tu taucte iis ate euhordloustotalGu aA 4 1 1 IAS TAIIATION NOCO iepener e EORR 4 1 2 Doc c ment CONVENTIONS ecrini TTE 4 to Preprocessing INC dIlaensnis nran a E de asteechies 4 1 3 1 Creating a relief parameters data Set ccc cecccccceccceeeeeeeseeeeeeeeeseeees 4 1 3 2 Creating soil parameters files from raster files cccceceeeeseeeeeeeeenees T 1 3 3 Landuse related generation of a soil parameter data set using ge eue are TNC A A E E A E T EE R 9 1 3 4 Editino the lOOKUD Hle va care de cccesoceccuenen E EOR 10 1 3 9 Editing LNG data TG sands cosacciectascedns Qasoedea aecoatnadnscmtnedaranisadacannareocandaetosnca 11 1 3 6 Editing the grid Tl Cs svc ccececucncecnancngucrancnascnan danced moscnacconcnqncnonmeraqnssedss 11 TA SMUKO pe a R ST 11 120 LONG TSF SINIUlAUON LUONA eiserne aE E EEE E EEEO 14 1 5 1 Example 1 Long term simulation based on a single event 14 1 9 2 Example 2 Lo
11. In order to enter data the snow module must be switched on Example The sample data describes a melting event in February and lasts 48 hours The water equivalent is known for the start of the event The snow height is known for 3 dates The table shows that the snow is melted between the morning of the second day and the morning of the third day Based on the decline of the snow cover during the preceding day and the meteorological data one can assume that the snow will only last until the middle of the second day Date Water equivalent mm Snow height cm 19 02 1999 7 40 28 14 20 02 1999 7 40 4 21 02 1999 7 40 0 Table 2 Water equivalent and snow height A rainfall event starts on 19 February at 2 40 PM and ends on 20 February at 0 40 The maximum intensity is 0 05 mm min The temperature remains always above 0 C the minimum is on 19 February at 7 40 AM with 0 3 the maximum is on 20 February at 4 10 PM with 6 2 In the Meteo Select Precipitation zones dialog select the Rain data file n_s71_k1 csv and the Zone grid file meteozn asc Now open the snow model dialog with Meteo Snow model Choose the following files Temperature t s1_k1 csv Water equivalent we_s1_k1 csv Snowage age_s1_k1 csv As no wind data is available select T Index method Set the following values Transient zone for rain snow 1K Temperature limit for rain 0 6 C Temperature limit snow melt 0 Degree day factor 2 2mm d C The
12. a text editor When you examine the course of the simulated water equivalent the sum of solid and liquid storage you will find that the water equivalent is still too high on the third day Therefore you will have to increase the degree day factor in the snow model dialog Enter a value of 5 5 and re launch the simulation The snow result file shows that this time the snow cover is melted between 2 and 3 PM on the second day which corresponds to the previous assumption Figure 13 The sediment budget for this snow melt event is displayed in Figure 15 Compared to a normal summer rainstorm the sediment loss by erosion is rather high However snow melt events in conjunction with a high initial water equivalent rain and quick rising temperatures are rather rare 21 o Snow height cm A Water equiv measured mm Temperature poss corr Cumul precipitation mm Cumul runoff mm Water equiv simulated mm Temperature measured Figure 13 Diagram of snow model results The following maps show output examples of the exposition model Figure 14 22 Shadow gray on 19 02 1999 at 7 30 AM for the Temperature correction on 19 02 1999 at 7 30 AM sample data for the sample data Red warmer blue colder Water equivalent 20 02 1999 at 14 00 Light blue no snow dark blue 4mm water equivalent Figure 14 Results from the exposition model Erosion Deposition
13. all portion of sediment Nodata Nodata re eee o 200000 2 000000 2 000000 20 000000 20 000000 200 000000 200 000000 2000 00000 Figure 23 Deposition kg m in impoundment Figure 24 and Figure 25 display the hydrology of the two impoundments during the sample rainstorm The lower impoundment receives input from the discharge of the upper impoundment input channel flow and from overland flow input The stage and volume curves follow the curve of the input channel flow Due to the low input the lower impoundment is free from water after about 3000 intervals 21 days The same goes for the sediments Figure 26 and Figure 27 The lower impoundment receives a large amount of sediment in a high concentration from the overland flow That is the reason why the sediment concentration is quite high from the start 32 100000 10000 1000 100 500 1000 1500 2000 2500 3000 3500 0 1 0 01 0 001 Interval 10 min Figure 24 Hydrology of the sample data upper impoundment 10000 1000 4 100 1 I I I I I I 500 1000 1500 3500 4000 4500 5000 0 1 0 001 Interval 10 min Figure 25 Hydrology of the sample data lower impoundment 33 Stage m Volume m 3 Imp Area m 2 cum Channel flow in m 3 cum Channel flow out m43 Discharge m43 Stage m Volume m 3 Imp Area
14. e results are written to a data set At first the settings for the computation of the relief parameters must be chosen The command Relief Options offers several modes for the computation of slope and flow distribution Example In the Flow routing tab sheet set flow routing to divergent and in the slope computation tab sheet set the value to 4 neighbors The computation algorithm of EROSION 3D demands that the surface must not contain spurious pits Therefore in the Pits and planes tab sheet the Fill depressions and Treat flat areas check boxes should be switched on If the sinks are not filled a derived drainage network may be discontinuous Close the dialog with the Ok button After selecting the command Relief Hydro Create relief data set the dialog window Relief input file appears On the left side of the window a button with the label DEM file is located If you just started up EROSION 3D no values for filename rows columns and resolution are displayed next to the button Relef input file File Hame Hows Columns Cell size DEM file C Programme ge sder asc 146 108 10 Create output data set Cancel Figure 1 Relief input file dialog Press the DEM file button The File open dialog opens Select the file dem1 asc in the samples indata relief_hydro relief_tachy directory Open Look in Sy relief_tachy a denn ase History E a m i File name demi My Network F Files of type fai Fi
15. es tab sheet and select the file ts_ref22 10 par This file contains all the information for the long term simulation dialog lf you choose Save result relief at the end of each sequence iteration this operation can occupy a very high amount of hard disk space Close the dialog box with OK and start the simulation with Simulation Run Save the result data set in samples result longterm Its_ref22_10 rs In the relief data set you will find a new data set Its which contains the relief parameters of the modified terrain after the simulation The grid dem_re asc is the modified digital elevation model The difference in elevation after the simulation is shown in Figure 11 In the result data set you will find e ts_sum_sedvol a grid containing the cumulative sediment volume over all events and iterations e lts ch_sum_sedvol a grid containing the cumulative sediment volume in channel over all events and iterations e ts_sedbudget a grid containing the erosion deposition values for each grid cell A grid map of this file is shown in Figure 12 The result data set itself contains the results for the last event and last iteration As the rainfall event has a low intensity no erosion occurs The sediment volume that leaves the catchment through the main drain during the simulation is 64 t which corresponds to 0 897 t ha 17 _ Landuse Elevation difference m Figure 11 Changes in elevation after long term simulation
16. et Hame Rows Columns Cell size Relief outdatasreliet 146 108 10 Fall outdatasoil 0b044 146 108 10 Result No data set selected 0 T i Parameter Hame Steps Stations Resolution Precipitation edt vretyearo r 0604 cay E 10 mi Figure 8 Selection of parameter files for the simulation The command Simulation Run starts the computation The File format dialog opens There you can choose between ASCII and binary format For the example select Erosion 3D result data set Ascii Press ok The Save Result Data set dialog opens First you should create a new data set Press the New folder button and enter a name for the new data set e g samples result 0604 rs A new directory is created Finally press the Save button Hint It is a good idea if you add file extensions to your data set names This makes it easier to identify the type of data relief soil result wnen you want to use the data set on a future occasion The status bar informs you about the current state of execution The computation of large study areas and or small cell sizes can take very long depending on the computer hardware The computation is finished successfully when the message box Normal termination is displayed Confirm with Ok The computation results are written automatically into the data set Thus a final saving is neither necessary nor possible Choose Result View result data set and select the data set that you just created e g samples
17. evaporation correction should be switched on The storage capacity of the snow for water need not be set because it is determined by the model as the snow age is known Next change to the exposition tab and switch on the Perform exposition correction check box Now enter the following values Scaling factor for temperature correction 1 moderate temperature deviation Control parameter Radiation temperature Geographical latitude 51 3 20 Geographical longitude 13 1 Center meridian 15 Time difference h 1 The SSD file is named ssd_s7_k2 csv Set the save corrected temperatures box to Every interval so you can watch the temperature deviations in the watershed In the Frozen soil tab select Frozen soil and set the Fraction of infiltration to 0 In the Watch cell tab select Watch all parameters cell and set Row to 50 and Col to 50 With these settings you will generate a file snow csv that will contain all relevant snow parameters for every time interval of the specified cell You can save the snow parameters with the Save as button Finally close the dialog with Ok For the simulation you will also need a relief and a soil data set Relief Hydro Select relief data set and Soil landuse Select soil data set Start the simulation with Simulation Run When the simulation is finished you will find the file snow csv in the result data set s directory You can open this file with Excel or
18. int options are written to the relief data set In the following example two impoundments form a cascade Example Select the relief parameter data set samples outdata checkdam cd1_2 rel with the menu item Relief Hydro Select relief data set Select the soil parameters data set samples outdata soi 0604 with Soil Landuse Select soil data set In order to demonstrate the hydrological and sedimentation behavior after one rainstorm an artificial and unrealistically strong event with a sum of 187 mm within two hours was created The precipitation parameters are selected in the dialog box that is opened Example Select the precipitation parameters file samples indata meteo e3d32 cdrain extr100a csv with Meteo Precipitation Zones In the check dam options switch on the model with the Run model checkbox Also check Save stage volume list Save hydro data Save sediment data Do not check Save lake cover as this option will use a large amount of disk space Start the computation with Simulation Run Figure 22 shows the position and maximum extents of the two impoundments Figure 22 Maximum extent of impoundment according to check dam height 31 Figure 23 shows the actual maximum extent of the impoundment after the sample rainstorm The colors indicate the amount of sediment that was deposited in the impoundment The major fraction of the mobilized sediment is captured in the upper impoundment The lower impoundment receives only a sm
19. les Cancel Figure 2 Selecting a file name for the digital elevation model Erosion 3D can recognize several file formats automatically Arc Info ASCII files Grass Raster files and Surfer 6 Grid files otherwise you will be prompted to tell the program what format your file has File format Specify tile format pii lato ASCII ree Figure 3 Selecting a grid file format Now the dialog window Relief input file displays the file characteristics After pressing the Create output data set button the File format dialog appears There you can choose between ASCII and binary format For the example select Erosion 3D relief data set Ascii Press ok The Save Relief Data set dialog opens First you should create a new data set Press the New folder button and enter a name for the new data set e g samples outdata relief_test A new directory is created Finally press the Save button The Create file dialog appears and shows the characteristics of the new data set Create file Data set West 4596700 4587770 East 5623400 South Number of cells Columns 108 Cell size m fi T Rows 146 Nodata 3999 Cancel Help Figure 4 File characteristics Press Ok again the computation of the relief parameters starts now During the computation the current state of processing is displayed in the status bar On the graphics screen you will see the drainage network that was derived from the
20. lg 4587080 5623560 The cell containing point 4587080 000 5623560 000 has value 450 000 Grid gridedit edit damlg Floating Point grid Grid gridedit fillvalue nodata Grid gridedit fillcell 45387080 5623560 Grid gridedit save Saving changes for d user delphi3 e3d32 checkdam dams damlg Floating Point grid Finally the dam grid is merged with the original DEM Grid damlgrid merge damig deml The grid is converted to Asciigrid format with Afo gridasc ii damlgrid damloqrrd asc 25 1 7 2 Simulation with Erosion 3D Now move to Erosion 3D and create a relief data set using the new grid dam1grid asc Select Relief Hydro Check dam model Enter pour points The DEM and the channel network are displayed Select the pour point tool 4 Identify the location of the pour point row 130 5623560 column 39 4587080 Only channel elements can be assigned the pour point property All stage values must be entered in meters above sea level Enter the following values for ID 1 Elevation min 441 86 Elevation max 450 Infiltration 0 001 Evaporation 0 1 Move to the Stage Discharge data tab and enter the following values Stage m Discharge m 3 s 444 5 0 000 445 0 010 446 0 015 447 0 020 448 0 025 449 0 030 450 0 035 Table 3 Stage Discharge data The stage value 444 5 m is the minimum stage below which no discharge takes place Close the map window by selecting View Close graphics or by pressing the ps
21. ll events and iterations e ts_sedbudget a grid containing the erosion deposition values for each grid cell A grid map of this file is shown in Figure 10 e aresult data set for each iteration i1 110 The sediment volume that leaves the catchment through the main drain during the simulation is 27 t which corresponds to 0 377 t ha These values can be read at the watershed outlet from the ts_ch_sum_sedvol file unit of measurement kg m 14 Landuse Elevation difference m 0 1 0 001 _ 0 001 0 001 0 001 0 1 i 0 3 0 4 ME No Data Figure 9 Changes in elevation after long term simulation Erosion Deposition t ha E lt 250 F 250 25 25 2 5 2 5 0 01 _ 0 01 0 01 6 0 01 2 5 Pe 2 5 25 Be 25 250 E gt 250 __ No Data Figure 10 Total sediment budget after long term simulation Note The project can also be run with the project file 0604 70 par which is located in the samples directory 1 5 2 Example 2 Long term simulation based on a reference year The average annual sediment yield is to be calculated for a small catchment For the following simulation the precipitation parameters are taken from the reference year rainfall scenario A reference year consists of a chronological series of single rainstorms which occur within the period from May to September Each rainfall event requires its own soil data set whose parameters account for the
22. lt data set imp_sed csv which shows some results for the sediment budget of the impoundment and imp_hyd csv which shows hydrological parameters The maximum extent of the impoundment according to the check dam height is shown in Figure 16 The dam is located on the westerly side of the impoundment Figure 16 Maximum extent of impoundment according to check dam height Figure 17 shows the actual maximum extent of the impoundment after the sample rainstorm The colors indicate the amount of sediment that was deposited in the impoundment 2 Nodata Nodata sel Aah ta ENTTT o200000 2 000000 l 2 000000 20 000000 20 000000 200 000000 200 000000 2000 00000 Figure 17 Deposition kg m in impoundment 10000 1000 100 Stage m Volume m 3 Imp Area m 2 cum Channel flow in m 3 cum Channel flow out m 3 Discharge m 3 1000 1500 2000 2500 0 1 0 01 0 001 Interval 10 min Figure 18 Hydrology of the sample data with infiltration and evaporation 28 1000000 100000 10000 1000 Deposition Clay kg Deposition Silt kg Deposition Sand kg Sed Conc kg m 43 Imp volume m43 Sed volume kg 100 1500 2000 2500 3000 3500 0 1 0 01 0 001 Interval 10min Figure 19 Sedimentation behavior of the impoundment with infi
23. ltration and evaporation Figure 18 shows that the discharge from the impoundment starts one hour after the begin of the rainstorm when the impoundment stage is higher than the minimum discharge stage of the outlet structure The maximum value is 5 6 m for the 10min interval After 45 hours the discharge ceases After that the volume is only decreased by infiltration and evaporation At the end of 28 days there is no water left in the impoundment Figure 19 shows the sedimentation behavior of the impoundment The deposition of sand is not visible in the resolution of the diagram as it takes place as long as inflow occurs during the first hour of sedimentation The deposition of the silt fraction ends after 7 hours whereas the deposition of the clay particles is stopped when the remaining water is evaporated and infiltrated after 28 days The sediment concentration increases slowly as the water content of the impoundment decreases Finally the sediment concentration exceeds the upper limit and the sediment volume is deposited resulting in a drop of the sediment volume and arise in the clay deposition Note The project can also be run with the project file cd1 par which is located in the samples directory Figure 20 and Figure 21 show the same situation but with the theoretical assumption that no infiltration and evaporation occur The duration of discharge lasts longer as there are no other water losses After discharge ceases the volume
24. m 2 cum Channel flow in m3 cum Channel flow out m 3 Discharge m43 1000000 100000 Deposition Clay kg Deposition Silt kg Deposition Sand kg Sed Conc kg m 43 Imp volume m43 Sed volume kg 1 T T 500 1000 1500 2000 2500 3000 3500 4000 0 1 0 01 0 001 Interval 10min Figure 26 Sedimentation behavior of the upper impoundment 100000 Deposition Clay kg Deposition Silt kg Deposition Sand kg Sed Conc kg m 3 Imp volume m 3 Sed volume kg 1000 1500 2000 2500 3000 3500 4000 4500 0 1 0 01 0 001 Interval 10min Figure 27 Sedimentation behavior of the lower impoundment Note The project can also be run with the project file cd1_2 par which is located in the samples directory 34
25. ng term simulation based on a reference year 16 1 6 Snow model tutOrial ccc eecc cece eeeceeeeeeeeeeeeeeeeeeseeeseeeseeeseeeseeeeeeseeees 20 Wh CHECK Gain Modelt toral css lena tins inchdaclGeatdnets 25 1 7 1 Preparation Of DEM bescscdnaccaassnsadacadenataes aaaisasi saedsrddanatand anaisasd oaadsrddnonins 25 1 7 2 Simulation with EroSiOn 3D cccccceeccssecseeceeeceecceecaeecseesueecseseeesaees 26 1 7 3 Handling two or more IMPOUNCMENLS ccccceecceeceeeeeeseeeeeeseeeeeenees 31 1 Sample project The sample data set is a small watershed that comprises an area of approximately 0 78 km The highest altitude is 526 m in the Northeast and the lowest altitude is 439 m in the south of the study area The average slope is 5 The corresponding grid consists of 108 146 cells with a spatial resolution of 10m 1 1 Installation notice For this tutorial you require the sample data from the installation CD The sample data is installed if you chose a full install or selected the sample data in the custom install option 1 2 Document conventions Italics denote file names or directory names Bold text denotes menu commands or dialog names Monospace Style text indicates information that is to be entered by the user 1 3 Preprocessing the data 1 3 1 Creating a relief parameters data set Before you can use your digital elevation model for simulation runs the data must first be pre processed Th
26. p1 txt as Lookup table file The button Create output data set builds the data set The File format dialog opens There you can choose between ASCII and binary format For the example select Erosion 3D soil data set Ascii Press ok The Save Soil Data set dialog opens First you should create a new data set Press the New folder button and enter a name for the new data set eg samples outdata soi Soil_rdb A new directory is created Finally press the Save button The Create file dialog appears and shows the characteristics of the new data set 1 3 4 Editing the lookup file In the example file Jookup1 txt winter barley wg is assigned to area number 85 in the Northwest of the terrain You want to investigate which impact on erosion processes has the shifting of land use from winter barley to meadow Open the file lookup1 txt in a text editor Search the patch number 85 Replace wg by wiese The delimiter between 85 and wiese must be preserved categorically Save the file by using a new name Create a new soil parameter data set by Soil landuse Create RDB soil data set Calculate the erosion for the entire terrain again by applying the original relief data and precipitation data 10 1 3 5 Editing the data file You will realize that the winter barley patch is covered just by 87 and not by 100 at June 29 because of the bad spring weather conditions Open the file juni csv by help of a text editor Go to row numbe
27. r 7 which ends with wg Go to the land cover column and change 100 to 87 Please do not remove blanks Save the file under a new name Create a new soil parameter data set by Soil landuse Create RDB soil data set Calculate the erosion for the entire terrain again by applying the original relief data and precipitation data 1 3 6 Editing the grid file Be careful while editing the grid file If alterations are needed better process within the GIS where you generated this file 1 4 Simulation The simulation requires the two pre processed data sets with relief and soil parameters and a precipitation file The menu item Relief Hydro Select relief data set sets the relief parameters data set Example Select the relief parameter data set samples outdatarelief relief_t The other two parameter groups are treated the same way Choose the Soil Landuse Select soil data set command to open the soil parameter data set The precipitation parameters are selected in the dialog box that is opened with Meteo Precipitation Zones Select the soil parameters data set samples outdata soil 0604 and the precipitation parameters file samples indata meteo e3d32 refyear 8_ O0604 csv Note that the relief and soil parameter data sets must be identical with respect to the number of rows and columns and the cell size The command Simulation Status gives information about the selected files Figure 8 11 Status Data s
28. r ten times in order to find out about the sediment losses and the change in topography Example For the simulation you need a relief samples outdatarelief relief_t and a soil samples outdata soil 0604 data set Relief Hydro Select relief data set and Soil landuse Select soil data set and a rain data file samples indata meteo e3d32 refyear 8_7_0604 csv Meteo Select precipitation zones Choose Simulation Long term simulation Check the Long term simulation on off checkbox Enter the following values in the Long term options tab Iterations 10 Result smooth passes 0 Result smooth radius 1 Save result at the end of each iteration Modify relief checked yes Relief radius 10 Relief smooth passes 0 Relief smooth radius 1 Save relief at the end of long term simulation Close the dialog box with OK and start the simulation with Simulation Run Save the data set to samples result longterm 0604 10 rs In the original relief data set you will find a new data set Its which contains the relief parameters of the modified terrain after the simulation The grid dem_re asc is the modified digital elevation model The difference in elevation after the simulation is shown in Figure 9 In the result data set you will find e ts_sum_sedvol a grid containing the cumulative sediment volume over all events and iterations e ts_ch_sum_sedvol a grid containing the cumulative sediment volume in channel over a
29. s created Finally press the Save button The Create file dialog appears and shows the characteristics of the new data set Create file Data set West 4586700 4587770 East 5623400 South Number of cells Columns 108 Cell size m fi T Rows 146 Modata omea e Figure 6 File characteristics Press Ok again the computation of the soil parameters starts now During the computation the current state of processing is displayed in the status bar 1 3 3 Landuse related generation of a soil parameter data set using relational files This type of soil parameter input is based on the following principle Usually on the areas in agricultural use a change in soil characteristics only occurs when there was a prior shifting of land use e g shifting of a patch boundary Soil characteristics within a patch may be equalized especially in the case of anthropogenic soil cultivation methods A homogeneous soil parameter data set can be assigned to a patch like this A vector file containing land use boundaries is the assumption for this kind of parameter generation Polygons have to be created from single segments within a GIS Numerical IDs are assigned to these polygons in order to enable an unambiguous identification A vector grid conversion must be processed within a GIS Grid elements each containing the ID of the polygon are located now inside the boundaries of this polygon The grid file must be converted to an
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