User`s Guide for Water Balance Toolbox (v. 2.2) for
Contents
1. gt 1 000 0 999 0 999 0 998 0998 0 997 0 996 0 99 1000 0 993 0 998 0 997 0 996 0 995 0 994 0 993 0 999 0 993 0 998 0 996 0 995 0 994 0 993 0 992 0 999 0 9599 0 998 0 997 0 996 0 994 0 993 0 992 S 1 000 0 999 0 998 0 998 0 997 0 996 0 995 0 994 1 000 1 000 1 000 0 999 0 999 0 998 0 998 0 997 1 000 1 000 1001 1001 1 001 1 001 1001 1 001 1 000 1001 1002 1002 1 003 1 003 1003 1 003 1001 1001 1 002 1003 1003 1 004 1 004 1 004 1001 1 001 1 002 1 003 1 003 1 004 1 004 1 004 1 000 1001 1 001 1 002 1 002 1 002 1 002 1 002 1000 1 000 1 000 1 000 1000 1 000 1 000 0 999 Page 10 PET Adjustment Coefficients have also been computed for another site using recorded temperature and radiation data for 2003 amp 2010 the PET Adjustment Coefficients for this site represent the average of these two years e McArthur OH Vinton Furnace Experimental Forest 39 N Monthly adjustment coefficients for the growing season April September for all five sites are available in the Water Balance toolbox as remap tables used in the B PET Coefficients model described below A detailed description of the procedures used to develop the Adjustment Coefficient grids is given in Appendix B and an ArcGIS model for creating adjustment coefficient grids is also available for download from the Water Ba2. Browse to and select the soil AWC grid for your study area In this example C WB Soils soil_ awc mm Click Add then OK Layer Properties General Source Extent Display Symbology Joins amp Relates Show of type Faster datasets Cancel Ok Cancel Apply Repeat these procedures for the other full storage grids Save the project Page 23 B Delta Storage Computes the difference in Storage from one month to the next this represents either plant utilization or recharge e Double click the B Delta Storage model then click OK Storage O1 StorageXST 01 Storage Oz StorageXST 02 Storage OF Storage ST_05 Storage 04 StorageXST 04 Storage 05 Storage ST 05 Storage 06 StorageXST 06 Storage OY StorageXST 07 Storage 0S Storage ST 08 Storage 09 StorageiST 09 Storage 10 B Delta Storage Computes the difference in Storage from one month to the next Storage ST 10 Storage 11 StorageXST 11 Storage 12 amp v v v v v v fe v v a Storage ST 12 Delta 5T 01 Tu Cancel Environments lt lt Hide Help Tool Help e The Delta Storage grids are added to the Table of Contents upon completion El Delta ST delta ST 12 delta ST 11 delta ST 10 delta 5T 09 delta ST 08 delta ST 07 delta ST 06 delta ST 05 delta ST 04 delta ST 03 delta ST 02 del
3. 0 998 0 997 0 997 0 996 135 165 SSE 1 000 1 000 1000 1 000 1 000 0 999 0 9993 0 998 165 195 s 1 00 1 00 1 001 1 0010 1 001 1 001 1 001 1 001 195 225 000 1 001 1 002 1 002 1 002 1 002 1 002 1 003 225 255 WS 000 1 001 1 002 1 002 1 002 1 003 1 003 1 003 255 285 000 1 001 1 001 1 002 1 002 1 002 1 002 1 002 285 315 000 1 001 1 001 1 001 1 001 1 001 1 000 1 000 315 345 NN 000 1 000 1 000 1 000 0 999 0 999 0 998 0 997 m ul sas 1045 15 20 20 25 25 30 30 35 3540 407 flat 000 ain EE s EN 345 360 0 15 15 45 45 75 75 105 105 135 135 165 165 195 1 000 0 999 0 999 0 333 0 998 0 337 0 997 0 996 0 999 0 993 0 998 0 997 0 996 0 995 0 994 0 993 0 999 0 998 0 997 0 996 0 995 0 994 0 993 0 992 0 999 0 998 0 997 0 996 0 995 0 994 0 994 0 992 0 999 0 999 0 998 0 997 0 997 0 996 0 995 0 994 1 000 1 000 0 999 0 999 0 999 0 998 0 998 0 997 1 00 1 001 1 001 1 001 1 001 1 001 1 001 1 000 1 000 195 225 SSW 1 001 1 001 1 002 1 002 1 002 1 003 1 003 1 003 1 003 225 255 WSW 1 001 1 001 1 002 1 003 1 003 1 003 1 004 1 004 1 004 255 285 1 000 1 001 1 002 1 003 1 003 1 003 1 003 1 003 1 003 285 315 1 000 1 001 1 002 1 002 1 002 1 002 1 002 1 002 1 002 315 345 1 000 1 001 1 001 1 001 1 000 1 000 1 000 1 000 0 999 SLOPE fla 1000
4. Climate Precip precip mm_08 Precipitation 09 Climate Precipiprecip mm 09 Precipitation 10 a Climate Precipiprecip mm 10 Precipitation 11 Climate Precip precip mm 11 Precipitation 12 a Climate Precipiprecip mm 12 AET 01 AETVAET 01 AET 02 AETVAET 02 z AET 03 AETVAET 03 AET 04 AETVAET 04 AET 05 P Cancel Environments lt lt Hide Help Tool Help Page 28 e Upon completion monthly Surplus grids are added to the Table of Contents Ei v Surplus Surplus Ann Surplus 12 Surplus 11 Surplus 10 Surplus 09 Surplus 08 Surplus 07 Surplus 06 Surplus 05 Surplus 04 Surplus 03 Surplus 02 HE Ed E EH Ed EE Ed E EH EH LI LI ELI ET ET EI E E ET ET DJ E11 E Surplus 01 5 Checks Verifies that the water budget is in balance and that there are no errors in computation 3 8 05 Checks A Checks e Double click the A Checks model then click OK Annual Precipitation A Checks Climate Precipiprecip mm 13 Annual PET Checks to see if water budget is in PETWPET Annual balance PET AET Deficit Annual SET Precipitation AET Surplus JAETMAET Annual O dd U o Annual Ceficit DeficittDEF Annual Annual Surplus Surplus Surplus Ann paesi CwBiChecksip ae s i pe ae def i Ci WBiChecksipe ae def i Cancel Environments lt lt Hide Help Tool Help Page 29 e Upon completion two Checks gr
5. Environments lt lt Hide Help Tool Help When each month has been added click OK Combined Slope Aspect Reclass Grid DEMNslopa aspi v ru Remap table with PET Adjustment Coefficients April 04 CAWBIPET CoeffsiPET Adj 39M 04 rmp a Remap table with PET Adjustment Coefficients May 05 c TWEBIPET CoeffsiPET Adj 39N O5 rmp S Remap table with PET Adjustment Coefficients June 06 CAWBIPET CoeffsiPET Adj 39N 06 rmp a Remap table with PET Adjustment Coefficients July 07 c WWWBIPET CoeffsiPET Adj 39N 07 rmp S Remap table with PET Adjustment Coefficients August 08 CAWBIPET CoeffsiPET Adj 39M 08 rmp a Remap table with PET Adjustment Coefficients September 09 c WWBIPET CoeffsiPET Adj 39N 09 rmp S PET Coefficient 04 C iWBIPETIPET coef 04 PET Coefficient 05 C MWBIPETIPET coef 05 PET Coefficient 06 CIWBIPETIPET coef 06 PET Coefficient 07 C WBIPETIPET coef 07 PET Coefficient 08 C WBYPET PET_coef_08 PET Coefficient 09 C WBIPETIPET coef 09 B PET Coefficients Using reclassed Topo Grid and user supplied remap tables creates PET Adjustment Coefficients Cancel Environments lt lt Hide Help Tool Help Page 12 e When completed grids of PET coef 04 09 are added to the Table of Contents These represent the multiplicative factor based upon topographic position for adjusting monthly PET grids computed p
6. 000 Multiplying PET values by these coefficients increases gt 1 or decreases lt 1 moisture demand based on topographic position ampa PAN es saw 10457 15 20 20 25 25 07 30357 ss am sa 345 360 0 15 N 1 000 1 000 1 000 1 000 0 999 0 999 0 999 0 998 15 45 NNE 1 000 0 999 0 999 0 998 0 998 0 997 0 996 0 996 45 75 ENE 1 000 0 999 0 998 0 998 0 997 0 996 0 995 0 995 75105 E 1 000 0 999 0 998 0 998 0 997 0 996 0995 0 995 105 135 ESE 1 000 0 999 0 999 0 998 0 997 0 997 0 996 0 996 135 165 SSE 1 000 1 000 0 999 0 999 0 999 0 998 0 998 0 997 1653195 S 000 1 000 1 000 1 000 1 000 1 000 1 000 1 000 000 1 001 1 001 1 001 1 001 1 002 1 002 1 002 000 1 001 1 001 1 002 1 002 1 003 1 003 1 003 ooo 1 001 1 002 1 002 1 003 1 003 1 003 1 003 000 1 001 1 001 1 002 1 002 1 002 1 002 1 002 000 1 000 1 001 1 001 1 001 1 001 1 001 1 001 5 10 10 15 15 20 20 25 25 30 30 35 35 40 40 ER m ku m m m 345 360 0 15 000 0 999 0 999 0 998 0 997 0 997 0 996 0 995 15 45 NNE 1000 0 99 0 998 0 997 0 996 0995 0 994 0 993 45 75 ooo 0 999 0 998 0 997 0 996 0995 0 994 0 993 75 105 E 1000 0999 0 998 0 998 0 997 0 996 0995 0 994 105 135 ESE 1 000 1 000 0 999 0 999
7. Factor The first tool computes the temperature component of the Turc equation above Since PET is temperature dependent if the monthly temperature lt zero then PET 0 the model first checks for negative temperatures The output is used as input for the subseguent PET tool e Double click on the model A Temp Factor then click OK January Temperature Grid A Temp Factor Climate Temp temp c_01 February Temperature Grid Provides temperature part of Turc Climate Temptemp c02 ej equation monthly temp factor March Temperature Grid 0 01 d 15 e pn for N c IMI M n lv ratures erature oi T ie nagae pads ri U such April Temperature Grid that PET 0 Output Temperature Climate TempVXtemp c 04 Factor grids are used as input for the May Temperature Grid PET model Climate Temp temp c_05 June Temperature Grid Climate Temp temp c_06 July Temperature Grid Climate Temp temp c_07 August Temperature Grid Climate Temp temp c_08 v September Temperature Grid B Climate Temp VXtemp c 09 October Temperature Grid Climate Temp temp c_10 November Temperature Grid Climate Temp temp c_11 December Temperature Grid Climate Temp Vtemp c 12 Turc Equation Temperature Factor January CA WBiClimateiTemp Factorsit factor 01 Turc Eguation Temperature Factor February CAwBiClimatelTemp Factorsit factor 02 Cancel Environments lt lt
8. Hide Help Tool Help e After the model is executed the new grids are added to the Table of Contents red exclamation points adjacent to the t factor grid names disappear E Temp Factors t factor 01 L t factor 02 L t factor 03 L t factor 04 t factor 05 t factor 06 t factor 07 L t factor 08 t factor 09 t factor 10 t factor 11 t factor 12 Page 7 B Radiation gt PET B1 humid B2 arid The model first calculates the R 50 component of the Turc equation converting from Wh m to cal cm by multiplying by 0 08598 then multiplies by Temp factor computed in previous step Users must select either the B1 humid model or the B2 arid model based on the climate of their study area If relative humidity is 5096 model B2 arid would be more appropriate which computes Potential Evapotranspiration with a Relative Humidity adjustment factor Dx RH a 70 where RH 1s the average monthly relative humidity value For users of the B2 model note that monthly relative humidity grids have not been pre added to the Table of Contents PET 0 013 x x R 50 x ESD In the example below the study area is in the eastern U S so the BI humid Radiation gt PET tool is used e Double click on the model B Radiation PET then click OK B1 humid Radiation gt PET b a Radiation 01 B1 humid Radiation Radiation rad 01 rs PET Radiation 02
9. PET pet annual pet adj 09 pet adj 05 pet adj 07 pet adj 06 O pet adj 05 O pet adj 04 PET coef 09 LJ PET coef 05 LJ PET coef 07 LJ PET coef 06 PET coef 05 LJ PET coef 04 OO pet 1 pet 11 OO pet 10 pet 09 pet 05 pet 07 pet 06 pet 05 pet 04 pet 05 OO pet 02 OO pet 01 Page 14 2 P PE Calculates P PE or moisture supply demand Positive values indicate that plants are able to meet moisture needs through precipitation negative values indicate that plants must turn to soil moisture storage to attempt to meet their moisture needs E amp 02 P PE ba A P PE A P PE e Double click on the model A P PE ya A P PE FET Annual CAWBNPETipet annual Potential Evapotranspiration 01 PETPET 01 m Potential Evapotranspiration 02 PETAPET D z Potential Evapotranspiration 03 PETXPET 13 z3 Adjusted Potential Evapotranspiration 04 PETipet adj 04 bd Adjusted Potential Evapotranspiration 05 PETXpet adj 05 m Adjusted Potential Evapotranspiration 06 PETipet adj 06 x Adjusted Potential Evapotranspiration OF PETXpet adj 07 m Adjusted Potential Evapotranspiration 05 PETipet adj 08 x Adjusted Potential Evapotranspiration 09 PETipet adj 09 m Potential Evapotranspiration 10 PETXPET 10 v Potential Evapotranspiration 11 PETXPET 11 ul Potential Evapotranspiratian 12 PETYPET 12 Precipitation 01 Climate Pr
10. Radiation rad 02 si G Calculates monthly and annual PET Radiation 03 according to Turc PET 0 013 T Radationrad 03 N 5 s T 15 R 50 Radiation input is Radiation 04 in Wh m2 which is converted to a tsalll j tjtjyj e 38 sien mating by 0 0859 Radiation 05 multiplies by Temp factor computed Radiation rad 05 5 previously Radiation 06 Radiation rad 06 r Radiation 07 Radiation rad 07 5 Radiation 08 Radiation rad 08 rs Radiation 09 Radiation rad 09 5 Radiation 10 Radiation rad 10 5 Radiation 11 Radiation rad 11 5 Radiation 12 Radiation rad 12 5 Turc Temp Factor 01 Climate Temp Factorsit factor 01 5 Turc Temp Factor 02 Climate Temp Factorsit factor 02 5 E Cancel Environments lt lt Hide Help Tool Help Page 8 e Upon completion grids PET 01 PET 12 are added to the Table of Contents El PET pet annual pet adj 09 pet adj 08 Cl pet adj 07 Cl pet adj 06 pet adj 05 pet adj 04 Cl PET coef 09 Cl PET coef 08 Ci PET coef 07 PET coef 06 Cl PET coef 05 PET coef 04 pet 12 pet 11 pet 10 pet 09 pet 08 pet 07 pet 06 pet 05 pet 04 pet 05 pet 02 pet 01 H amp E DH EI EI LI LI ET ET EJ EJ EJ DT ET PL ET ET H E Ed E BH E 1B PE Adjust Note The discussion here focuses on seasonal climates in the northern hemisphere in which maximum insolation occurs on southern aspects du
11. aet 02 aet 01 o Note Some Deficit grids may contain very small negative values lt 0 001 Although negative values make no sense conceptually they are small enough to be ignored Alternatively an if then statement can be added to the model setting negative values to zero 1 E E E E E E EE E Ed Ed Ed E 9 EEE EE Ed Ed FE Ed EH D LIDJEIETETEIEJET EI ET ET ETE B Storage Comes Full This model looks for the month s in which the Storage of individual cells comes full Soil Storage must first reach field capacity before there can be Surplus water Presumably plants have been utilizing soil moisture as the growing season progresses the soil moisture is then recharged usually through the fall and winter Page 26 e Double click the B Storage Comes Full model EXE B Storage Comes Full scil Awe EE ar ST Bi This model looks for the month s in StorageXST 01 which the Storage of Individual cells comes full Before there can be Storage ST 02 surplus sail Storage must first be um brought to field capacity ST D4 StorageXST 04 ST 05 ST 06 StorageXsT 06 ST O7 Storage ST_O7 ST 08 StorageXST 08 StorageXST 09 ST 10 Storage 5T 10 ST 11 StorageXST 11 ST 12 Storage ST_12 ST1stFull O1 Ci WBiStoragelSTI1stFull 01 STistFull_o CWB StoragelsT istFull_ Oz ST1stFull 03 CWB StoragelsT istFull_o3 STistFull 04 Cancel Envir
12. that the water balance final checks fail discrepancies should be minor Page 2 however If you need to align grids zoom into a single pixel and use the Measure Tool to determine the amount of x y shift required Then use the ArcGIS Shift tool to align the grid utilizing the tool s Input Snap Raster option Data Management Tools Projections and Transformations Raster Shift Using the Water Balance Toolbox in ArcGIS note the model was created using ArcGIS v 9 3 but has been successfully executed in ArcGIS v 10 Numerous grids will be created upon running the complete Water Balance Toolbox To aid with organization a Start Template mxd ArcGIS project is provided in the C WB folder Open this project and you will see that the Table of Contents is pre populated with all the grids that will be created by the model Since the grids have not yet been created a red exclamation point precedes each name Start Template mxd ArcMap ArcInfo o l e eE File Edit View Bookmarks Insert Selection Tools Window Help Editor id Benthic Terrain Modeler Menu v Spatial Analyst D c EAS 1
13. the plants do not utilize soil moisture storage In this case the monthly Storage grids can all be assigned as the Soil AWC grid which represents full storage See To set remaining storage grids to the Soil AWC grid instructions below If any monthly P PE grids are negative however the Storage model will need to be run Start the model for the month with first negative P PE values when Storage is full Storage can assumed to be full 1 e Storage A WC after consecutive months of positive P PE grids As an example using the P PE grids in the figure above Storage would be first run for April p pe 04 is the first month with negative values and was preceded by seven months of positive p pe values p pe 09 10 11 12 01 02 03 NOTE Since the Storage model involves dividing a grid by AWC the result will be No Data for pixels on the Storage grid where AWC 0 1 e where there is water Page 17 B4 05 Storage i Lagoa A Storage A Storage e Double click on the A Storage model go A storage days in month E3FP FE grid Far current month P PEXP PE E3 Daily P PE for current month P PEVDaily P PE Storage For current month Previous Storage A 4 Sail AWC Cancel Environments lt lt Hide Help Tool Help Page 18 Click error and warning icons for more information gt EE A Storage start in month where Storage is assumed full ST AVVC ie th
14. 11 604 T amp 5 E R Georeferencing Y EI x x IN Il mb lt amp lt RN ag Layers Pn ArcToolbox a Checks 3 3D Analyst Tools Q O pe ae def i Analysis Tools aR mo xA Cartography Tools sa s O paesi Conversion Tools amy EO Y Coverage Tools E Surplus Y Data Interoperability Tools I Surplus Ann gt Data Management Tools C Surplus 12 Y Geocoding Tools s J Surplus 11 x Ag Geostatistical Analyst Tools s LJ Surplus 10 a Linear Referencing Tools m O Surplus 09 Mobile Tools L Surplus 08 Multidimension Tools R s Surplus 07 Y Network Analyst Tools i 3j O Surplus 06 x Ap Samples 3j Surplus 05 Kp Schematics Tools dA Surplus 04 Server Tools xy mm C Surplus 03 x Ap Spatial Analyst Tools ze s LJ Surplus 02 x A Spatial Statistics Tools Ll Surplus 01 gt Tracking Analyst Tools EI ST 1st Full Water Balance 3 ST eq AWC 12 amp l LI ST eq AWC 11 s C ST eg AWC 10 C ST eg AWC 09 C ST eg AWC 08 C ST eg AWC 07 s L ST eg AWC 06 m 1 ST an AWC NS Display Source Selection Favorites Indes Search Results anieu KI IA Drawing v k gv AY 0 Arial vo BZU Av v v 2 IRANRA NAS 52N405 471 Feet Pre populated Table of Contents visible in Start Template mxd Note that the Water Balance toolset is automatically added to the ArcToolbox Assigning Names to Existing Grids If you used the file and naming conve
15. Daily P PE 02 O Daily P PE 01 E Ll p pe 1 Value High 67 6493 N Low 58 9065 E O p pe 11 Value N High 87 5313 Low 58 1355 E Ll p pe 10 value N High 53 5452 Low 0 461564 E Ll p pe 09 value N High 70 7697 Low 23 998 E Ll p pe 08 value N High 2 4501 Low 48 9151 E Ll p pe 07 value N High 15 0945 Low 46 6153 E O p pe O6 value N High 16 0418 Lowe 13 5281 Page 16 El O p pe 05 value High 25 0716 M 11 5174 El L p pe 04 value High 27 3211 M TRETE a O p pe 03 Value High 78 455 M 59 8824 E Ll p pe 02 Value High 62 1043 M 35 9988 E Ll p pe 01 Value High 61 3317 M 58 7288 El PET pet annual 3 Storage This model computes soil moisture storage monthly values representing storage on the last day of the month During execution the model employs a daily time step assuming decreasing availability of soil moisture 1 e only 50 of soil moisture need can be obtained when the soil is at 50 of field capacity Curve C from Mather 1974 Climatology Fundamentals and Applications McGraw Hill NY The model determines daily soil moisture demand P PE and availability Precipitation by dividing monthly values by the number of days in the month Because it does daily computations this model takes the longest time to execute be patient If monthly P PE values computed in the previous step are all positive there is no need to run this model supply P exceeds demand PE so
16. P PE 06 5 Storage For current month Previous Storage storageist 5 v 5 Soil AWC Ikoil awc mm OK Cancel Environments lt lt Hide Help Tool Help Seo Soil AWC soil Available Water Capacity mm For your convenience this table provides the number of days in each month 01 Jan 31 05 May 31 09 Sep 30 02 Feb 28 06 Jun 30 10 Oct 31 03 Mar 31 07 Jul 31 11 Nov 30 04 Apr 30 08 Aug 31 12 Dec 31 Page 20 e Continue torun the Storage model after monthly P PE grids become all positive since soil storage has to be recharged For instance in our example September P PE p pe 09 is positive but soil moisture has been utilized in each of the previous five months April August E O p pe 10 Value n High 53 5452 Low 0 461563 E Ll p pe 09 value High 70 7097 Low 23 998 E Ll p pe 08 value H High 2 4501 Low 48 9151 e In our example the Storage model was run for September and st 09 added to the Table of Contents Comparing it to the Soil AWC grid full storage we can see that more recharge is required soil storage 1s still not up to field capacity for all cells EI stus Value N High 160 Lowe 29 2407 O soil avec mm value N High 160 Low 35 1 Continue to run the Storage model for each month In our example the Storage model was run again for October month 10 st 10
17. System The map view will not be centered on your study area so you will need to zoom to it and set the projection e Zoom to Full Extent D The DEM grid should be visible You can turn off the individual DEM grid at this point but leave the DEM Group turned on If you are using ArcGIS 10 e Setthe Data Frame s coordinate system to match the DEM o Right click on the Data Frame s name Layers in the Table of Contents and select Properties From the Coordinate System tab click the Add Coordinate System icon and select Import Data Frame D T If you are using ArcGIS 9 e Set the Data Frame s coordinate system to match the DEM o Right click on the Data Frame s name Layers in the Table of Contents and select Properties Then select Import z Data Frame Properties E ETE El Checks Annotation Groups Estent Rectangles Frame Size and Position O ped General Data Frame Coordinate System Illumination Grids Map Cache W Current coordinate system Mo projection EI Surplus Surg Surg Surg Surg Surg Surg Lt Surg Transformations Surg Surg Surg Surg Surg O Surg E ST 1st O ST amp ST O ST O ST O ST Q m U 5 m d T Display sss Select a coordinate system m H Predefined Er H Layers iE lt custom gt o Browse to and select your DEM then s
18. Typical Meteorological Year TMY3 data http rredc nrel gov solar old data nsrdb 1991 2005 tmy3 Daily PET was summed for the two days to create a representative monthly value The ratio of average hourly temperature PET was standardized so that flat sites 0 1 slopes 1 Flat sites should be unaffected by diurnal variations in radiation temperature Note that the topographic adjustment factors vary monthly vary with latitude and are not symmetrical about a particular compass axis Instructions for creating your own PET adjustment coefficients including an ArcGIS model are available for download from the Water Balance Toolbox for ArcGIS web page Page 34 Appendix C Input Output grids used in the Water Balance toolbox 1 Turc PE A Temp Factor Input e Average monthly temperature C o example ClimateNTempMemp c 01 Output e Monthly temperature factors t factor 777 o example C WB Climate Temp_Factors t_factor_01 B Radiation gt PET Inputs e Monthly temperature factors from above o example Climate Temp FactorsX factor 01 e Monthly radiation from Solar Analyst WH m o example Radiation ad Ol e Monthly relative humidity 96 optional used with the B2 arid model Output e Monthly PET PET ZZ in mm o example C WB PET PET_O1 1B PE Adjust A Create Topo Grid Input e Slope grid e Aspect grid Output e Reclassed slope and aspect grid o C WB DEM slop9_asp12 B PET Coefficients In
19. User s Guide for Water Balance Toolbox v 2 2 for ArcGIS James Dyer last modified March 2015 Department of Geography Ohio University A Water Balance Primer All organisms reguire energy and moisture and these two factors have an interactive influence A water balance or budget explores the relationship between energy and moisture at a place by modeling moisture demand potential evapotranspiration and supply precipitation and soil moisture storage If all soil pores are filled with water the soil is saturated Gravitational water drains away leaving a film of capillary water and the soil is at field capacity This is the Available Water Capacity AWC and is the water used by plants If this water is used up so that only hygroscopic water remains the permanent wilting point has been reached Glossary of terms e Potential evapotranspiration PET PE POTET E is the evaporative water loss from a vegetated surface in which water is not a limiting factor it depends mainly on heat and radiation e Actual evapotranspiration refers to water loss from a vegetated surface given water availability and 1s equal to available water or potential evapotranspiration whichever is less e Deficit refers to evaporative demand not met by available water or the difference between potential and actual evapotranspiration e Surplus is excess water not evaporated or transpired that leaves a site through runoff or subsurface flow e Available W
20. ater Capacity AWC is the maximum amount of water that the soil can store representing the soil s field capacity Before You Start Important Information For ease of use the model executes with default filenames and file locations The downloaded zipped folder containing the Water Balance Toolbox includes a nested series of blank folders named WB For ease of use you should unzip this folder to your computer s C N drive 1 e C WB If not many automatic grid names will have to be changed in each of the Toolbox s models increasing execution time and the likelihood of making an error Nested within the WB folder is a folder called New to Copy After you run the complete water balance model you can copy the entire C WB folder to a new location you may wish to give it a new name e g WB Study Area Name and re create an empty C WB folder to run a new model simply copy the contents of New to Copy to the new C WB folder What you will need for your study area before you start e Adigital elevation model DEM X Y units should be the same as elevation Z units o Use ArcCatalog to copy the DEM to the C WB DEM folder o When the Water Balance Toolbox is started in ArcGIS this grid will be named DEM in the Table of Contents o Arecommended but optional tool requires slope and aspect grids named Slope and Aspect in the Table of Contents after creating these grids from your DEM in ArcGIS copy
21. can be uploaded to define your Area of Interest Z Click on the Download Soils Data button along the top of the screen d Preparing the grid for use in the Water Balance toolbox e After downloading and unzipping the soil data from the Web Soil Survey double click on the soil data mdb file to open it in Microsoft Access 2010 e If prompted Stop all Macros and Enable Content e Exit out of the Soil Reports window that appears e In the left navigation panel select Tables Double click on muaggatt map unit aggregated attribute table to view it e Click on the External data tab at the top of the screen and select the Export to Excel spreadsheet icon o Inthe File format window select Excel 97 Excel 2003 Workbook xls o Do not check Export data with formatting and layout e Open the new file in Excel e You will need to retain columns mukey and aws0100wta Available Water Storage 0 100 cm Weighted Average although other depths are available if preferred e Since the aws value is in cm create a new column AWC mm multiplying aws x 10 Note Water polygons have a No Data value for AWC e Save the Excel file keeping the xls format Close it You can now add this Excel file to ArcGIS and join it to the soilmu a shapefile found in the downloaded spatial folder Page 32 e Convert this joined polygon shapefile to a gr
22. ds For the output raster enter C WB Climate precip mm_13 For the Overlay statistic select SUM Click OK e Monthlyradiation grids o Copy to C WB Radiation o These grids will be named rad 01 rad 12 in the model e Asoilavailable water capacity AWC grid o Copy to C WB Soils o This grid will be named soil_awc_mm in the model e Optional for arid environments relative humidity lt 50 Monthly relative humidity grids o No default location is specified in the model these grids could also be copied to C WB Climate using ArcCatalog Refer to Appendix A for a more detailed description including information about specific data preparation used for the sample grids in the examples that follow There is additional information on the Water Balance Toolbox for ArcGIS web page with information about acquiring these grids A word about the grids used in the model e All input grids e g climate soil should be same resolution as DEM If necessary use Data Management Tools Raster Raster Processing Resample or Spatial Analyst Tools Generalization Aggregate All grids are floating point Use Spatial Analyst Tools Math Float if necessary All grids should be in the same projection If necessary Data Management Tools Projections and Transformations Raster Project Raster e Cells for all grids should align Subtracting two grids whose cells are misaligned may result in erroneous values such
23. e first month after winter spring recharge in which some grid cells in the P PE grid take on a negative value Model computes soil moisture storage monthly value based on the last day of tha month Uses daily time step assuming decreasing avallability of sail moisture Mather 1974 curve C WATBUG default e Using the example above the Storage model will first be run for April since p pe 04 was the first monthly grid with negative values A Storage f f teemat 1 Previous Storage P PE grid For current month storage mm for previous month Note when model is first run no Previous Storage grid has been 30 P PEip pe 04 5 P PEADaily P PE 04 5 created yet However since Storage E Daily P PE Far current month for the previous month is assumed full use the AWC mm grid for Previous Storage for this model run only Storage for current month 4 j LI 2 a soil awc mm 1 x OK Cancel Environments lt lt Hide Help Tool Help e Enter the number of days in the month 30 for April and the month number 04 in this example for the P PE Daily P PE and current month Storage grids e Since this is the first execution of the model there is no Previous Storage grid But we are assuming that Storage is full at the start of April For this starting month therefore select the Soil AWC grid soil awc mm from the dropdown list e When the model execu
24. ecipkprecip mm 01 w y A P PE Calculates moisture supply P demand PET Cancel Environments lt lt Hide Help Tool Help o Note the model assumes that you previously ran the PET Adjust tool model 1B If you did not you will need to specify the original PET grids instead of the Adjusted Potential Evapotranspiration grids months 04 09 as shown in this figure wn A P PE PETAPET 13 5 Adjusted Potential Evapotranspiration 04 PETipet 04 v Adjusted Potential Evapotranspiration 05 PET pet 05 hy Adjusted Potential Evapotranspiration 06 PET pet m Adjusted Potential Evapotranspiration 07 PET4pet 7 s Adjusted Potential Evapotranspiration 05 PET4pet 05 kul Adjusted Potential Evapotranspiratior 09 PET4pet 3 kul Page 15 PETYPET 10 n sl 117 pes Adjusted Potential Evapotranspiration 04 Adjusted April Potential Evapotranspiration mm If you did not run the PET Adjust tool enter the original PET 4 instead e Click OK Several erids are added to the Table of Contents Annual PET Monthly P PE and Daily P PE necessary for the subseguent Storage tool Your P PE values will be different than in the example below E P PE Daily P PE 12 Daily P PE 11 Daily P PE 10 O Daily P PE 09 O Daily P PE 08 Daily P PE 07 Daily P PE 06 O Daily P PE 05 Daily P PE 04 O Daily P PE 03
25. ect the table for the appropriate month selecting the site closest to the latitude of your study area In the example 39 N Elkins WV is selected jn B PET Coefficients Combined Slope Aspect Reclass Grid DEMNslopa aspi z o 2 Remap table with PET Adjustment Coefficients ssi 04 Le JL js Remap table with PET Adjustment nefficien April 02 Look in W PET Coeffs ei Far Name Date modified C WBYPET PET_coef_07 on N Remap table with PET Adjustment Coefficients Rec T x S PET Adj 35N 07 rmp 2 14 2013 2 48 PM Z PET Adj 35N 08 rmp 2 14 2013 2 48 PM Remap table with PET Adjustment Coefficients A PET Adj 35N 09 rmp 2 14 2013 2 48 PM Desktop PET Adj 37M 04 rmp 2 14 2013 2 48 PM Remap table with PET Adjustment Coefficients 9 e 2 PET Adj 37N 05 rmp 2 14 2013 2 48 PM PET Adj 37N 06 rmp 2 14 2013 2 48 PM PET Coefficient 04 Libraries PET Adj 37N 07 rmp 2 14 2013 2 48 PM C WWBIPETIPET coef 04 A PET Adj 37N 08 rmp 2 14 2013 2 48 PM PET Coefficient 05 us PET Adj 37N 05 rmp 2 14 2013 2 48 PM C WEBIPETIPET coef 05 oe PET Adj 39N 04 rmp 2 14 2013 2 48 PM PET Coefficient 06 PET Adj 39N 05 rmp 2 14 2013 2 48 PM CAWBIPETIPET coef 06 E 7 PET Coefficient 07 rae PET Adi 39N 04 rmp v PET Coefficient 05 Files of type File RMP Cancel C WBIPETIPET_coef_08 Open as read only PET Coefficient 09 CAWEBAPETAPET coef 09 L Cancel
26. elect Add then OK Page 5 Save the Project Use File Save As to rename the Start Template mxd project to a more meaningful name In this example C WB WB_SCBI mxd Note the Water Balance Toolbox utilizes the Spatial Analyst extension If necessary turn on the extension Tools drop down menus gt Extensions Running the Water Balance Toolset All models in the Water Balance Toolbox can be run by double clicking and entering model parameter values Grids will be added to the Table of Contents as each model runs Grids are turned off unchecked to reduce redrawing time but can be turned on for viewing Note A Hillshade of your DEM Spatial Analyst Tools Surface Hillshade set to 50 transparency and viewed over your Water Balance grids provides a good topographic influence perspective Expand the Water Balance toolbox We will run the models in zm Water Balance sequence by double clicking on the appropriate model name Ee 01 Turc PE ji Lagke A Temp Factor A B1 humid Radiation PET H 01B PE Adjust m g 02 P PE DE 3 Storage Eja 04 AET ER 05 Checks 1 Turc PE Calculates monthly Potential Evapotranspiration according to Turc 1961 PET 0 013 x d x R 50 mE T 15 where PET is potential evapotranspiration mm T is temperature C and R is radiation Wh m 28 Water Balance 51 85 01 Turc PE o bega A Temp Factor qe B1 humid Radiation gt PET Page 6 A Temp
27. ever ST ZAWC AE PE water is coming from P e As ST 1s depleted it becomes increasingly difficult for plants to extract the water they need e When ST lt AWC AE P A ST AE may be less than PE It can never be more E Deficit PE AE By how much plants came up short F Surplus If ST is full AWC there s liable to be excess precipitation plants don t use it all e If ST lt AWC there can be no Surplus e If ST AWC then S P AE e Note the month when ST reaches AWC S P AE AST excess first went to fill Storage G Checks on annual totals e PE AE D e P AE S Page 38
28. had values less than the Soil AWC erid so the Storage model was run for November month 11 The values for st 11 are the same as for Soil AWC so soil storage may be full 1 e at field capacity p Ll stii value N High 160 Low 35 1 a U st 10 value High 160 Low 34 3257 I st 09 value N High 160 Low 29 2407 Page 21 O soil avec mm value N High 160 Low 35 1 To be sure that the storage grid is identical to the Soil AWC grid subtract the storage grid st 11 in our example from the AWC grid Spatial Analyst Tools gt Math gt Minus saved to the C WB working folder P Minus f fam Input raster or constant value 1 i Minus i soil avec mm i Input raster or constant value 2 Subtracts the value of the second Storageist 11 5 Input raster from the value of the first Output raster Input raster on a cell by cell basis C hWBiworkinglawest dt within the Analysis window OK Cancel Environments lt lt Hide Help Tool Help The result is zero for all cells indicating that storage is at field capacity EI awwc st 11 Value High ll If the resulting grid contained non zero positive values the Storage model would need to be run again for the next month The minus grid can be removed from the Table of Contents after viewing When Storage is full you can continue to run the Storage model It is time consuming to execute
29. hecks Monthly Surplus mm o C WB Surplus Surplus_ Annual Surplus mm o C WB Surplus Surplus_Ann A Checks Inputs O 9 e oe o Annual precipitation Climate Precip precip mm_13 mm Annual Potential Evapotranspiration PENPET Annual mm Annual Actual Evapotranspiration AFETAET Annual mm Annual Deficit DeficiNDef Annual mm Annual Surplus SurplusNSurplus Ann mm utput P AE Surplus check grid all zeros if checks hold o CNWBWChecksW ae s 1 PE AF Deficit check grid all zeros if checks hold o CNWBWChecksWpe ae def 1 Page 37 Appendix D Conceptual steps in computing a water balance You will need P precipitation supply and PE potential evapotranspiration demand to start A P PE gt tells when demand exceeds supply P PE will be negative e If supply P lt demand PE plants utilize soil water e If supply P gt demand PE there is more water than plants need e Available water is prioritized as follows 1 Plants use what they want first from precipitation then from soil storage 2 If there is still water leftover it is used to recharge storage if 1t is not full 3 Any excess water becomes surplus B Determine where soil water storage ST will be full AWC based on consecutive values of P PE C AST change in ST from month to month water used by plants or to recharge storage D AE what plants use If water is not limiting plants take what they want AE PE e When
30. however so it will save time to assign the remaining storage grids the same values as the Soil AWC grid Be sure however that a subsequent month s P PE grid does not assume negative values 1 e P PE values are negative one month then positive then negative again the Storage model must be run for any month with negative P PE values To set remaining storage grids to the Soil AWC grid o Inthis example st 11 is full and P PE is positive for December March months 12 03 Positive P PE means that plants are not drawing upon soil moisture so Storage will remain full for each of those months Therefore rather than continuing to run the Storage module you can Set Data Source for those storage grids setting them to the values of the soil AWC grid which represents full storage o Right click on the red exclamation point adjacent to the Storage grid in this example st 12 in the Table of Contents and select Properties EI Storage st 12 gLlstii Value R High 160 Low 35 1 Page 22 In the Layer Properties window that opens select Set Data Source General Source Extent Display Symbology Joins amp Relates Property El Raster Information Columns and Rows Number of Bands Cellsize X Y Uncompressed Size Format Source Type Pixel Type Pixel Depth Data Source File System Raster Folder CWB Storage Raster st_12 Set Data Source OK Cancel
31. id o ArcToolbox Conversion Tools To Raster Polygon to Raster Input soils shapefile Value field AWC mm Output soil AWC mm Cell Assignment Type MAXIMUM COMBINED AREA Cellsize 2 same cellsize as the DEM you will use for the water balance analysis you can browse to the DEM and select it O OU O O O 4 Obtain monthly temperature and precipitation data a In the current example I obtained 1981 2010 climatic normals from NOAA s National Climatic Data Center Data need to be properly formatted and converted to C and mm Annual values should also be computed JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC mly tavg normal 329R 362R 432R 543R 624R 712R 750R 739R 666R 561R 464R 363R mly prcp normal 244R 265R 376R 326R 420R 403R 330R 306R 450R 315R 375R 282R Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Temp F 32 9 36 2 43 2 54 3 62 4 712 75 73 9 66 6 56 1 46 4 36 3 54 5 Precip In 2 44 2 65 3 76 3 26 4 20 4 03 3 30 3 06 4 50 3 15 3 75 2 82 40 92 Temp C 0 5 2 3 6 2 12 4 16 9 21 8 23 9 23 3 19 2 13 4 8 0 2 4 12 5 Precip mm 62 0 67 3 95 5 82 8 106 7 102 4 83 8 77 7 114 3 80 0 95 3 71 6 1039 4 1 Monthly climate grids can be created by multiplying the DEM by zero Spatial Analyst Tools Math Times for each necessary monthly grid 25 monthly temperature and precipitation annual precipitation ii Then add the appropriate climate value to the zero grid to create individual temperature or
32. ids are added to the Table of Contents EI Checks a O pe ae def i m aU paesi E 0 e These represent the following checks the 1 indicates that they are integer grids PET AET Deficit Precipitation AET Surplus Resulting annual grids should have all zero values if checks hold If this is not the case see the troubleshooting section below Troubleshooting check grids not composed of all zeros By following all of the naming conventions potential errors should be minimized If the checks do not hold however refer to the following for troubleshooting ideas e First consider the magnitude of the errors keeping in mind that the units are millimeters of water If for instance annual precipitation is 1000 mm and the maximum error in your Checks grids is 2 mm this represents a 0 2 error which you may consider negligible o Very small errors may be due to grids misaligning For example cells of your climate grid may not align exactly with your radiation grid derived from the DEM The result could be that the P PE procedure subtracts the value of the pixel adjacent to the target cell resulting in small discrepancies See the section A word about the grids used in the model e If one of the Check grids is all zeros and the other is not this indicates in what steps the error may have occurred For example if one Check grid contains all zeros but the other does not then the AET calculations cannot be the p
33. ions a red exclamation point will appear next to the deleted grid names You can remove these from the Table of Contents and re save the project Page 30 APPENDICES A B P y Notes on Data Preparation and Grid Creation used in this User Manual Procedure used for computing PET adjustment coefficients Input Output grids used in the Water Balance toolbox Conceptual steps in computing a water balance Page 31 Appendix A Notes on Data Preparation and Grid Creation used in this User Manual In the examples used in this user manual all grids are in the same projection using Data Management Tools Projections and Transformations Raster Project Raster as necessary Specifically the DEM and all grids are in UTM with this projection x y units meters are the same as the z elevation units which is another requirement for DEMs in the model 1 The Digital Elevation Model was downloaded from the USGS National Map Viewer selecting the finest resolution available 2 In ArcGIS a rectangular shapefile of the study area was created so that input grids including the DEM can be clipped to a common extent Data Management Tools Raster Raster Processing Clip 3 Soil Data Available Water Capacity can be downloaded from the USDA NRCS Web Soil survey web page Step by step instructions a Start Web Soil Survey b Define Area of Interest The study area shapefile created in Step 2
34. lance Toolbox for ArcGIS web page E 016 PE Adjust qu A Create Topo Gri d jon B PET Coefficients A Create Topo Grid e Double click on the model A Create Topo Grid e In the drop down select the Slope and Aspect Grids then click OK jon A Create Topo Grid a Slope Grid A Create Topo Grid DEM Slope 5 Aspect Grid Reclasses slope and aspect grids to DEMMAspect 5 create topographic class grid Combined Slope Aspect Reclass Grid CAWBIDEMislop3 asp12 OK Cancel Environments lt lt Hide Help Tool Help e The grid slop9_asp12 is added to the Table of Contents Ej R DEM O slop3 aspl Aspect Slope DEM The 93 classes in the grid represent combinations of slope and aspect For example an east facing pixel with a 22 slope would be assigned a reclass value of 45 40 5 Reclass Reclass Aspect Value flatp1 J o 345 360 0 215 N 10 1545 NNE 20 4575 ENE 30 754055 E 40 50 60 70 80 90 2552855 w 100 285 3157 WNW 110 31 345 NNW 120 Page 11 Value 1 O cO J Ov Un 4 WwW N B PET Coefficients Remap table with PET Adjustment Coefficients Remap table with PET Adjustment Coefficients Double click on the model B PET Coefficients Specify a Remap table rmp for each month in the growing season April September Unless you have computed your own values browse to the folder C WB PET_Coeffs and sel
35. mm for previous month Storage ST since full storage AWC Output e Storage for the current month ST ZZ in mm o example C WB Storage ST_04 B Delta Storage Inputs e Storage for each month e g Storage st_04 mm Output e Delta Storage Difference in Storage for each month in mm o example C WB Storage delta_ST_0O5 4 AET A AET Inputs Average monthly precipitation Climate Precip precip mm_ mm o e Potential evapotranspiration PETNPET ZZ or Adjusted PET PETWadj pet 77 mm e P PE grids P PE p pe_ mm e Delta Storage grids Delta ST delta ST ZZ mm Page 36 Outputs Monthly actual evapotranspiration mm o CNWBNAETNAET Monthly deficit mm o CNWBNDeficitNDef FX Annual actual evapotranspiration mm o CNWBNAETNAET Annual Annual deficit mm o CNWBNDeficitNDef Annual B Storage Comes Full Inputs Soil AWC grid SoiNsoil awc mm Storage for each month e g Storagewt 08 mm Output Storage first full grid for each month values 1 first full or O o example C WB Storage st1stfull_09 Storage AWC grids 1 yes 0 no o example CNWBNStorageNST eg AWC 09 C Surplus Inputs e Average monthly precipitation Climate Precip precip mm_ mm e Monthly actual evapotranspiration AETNaet ZZ mm e Storage AWC grids ST 1st FulNST eg AWC 7 6 1 0 e Delta Storage grid Delta ST delta ST ff mm e Storage first full grid ST 1 FullNSTIstFull 4 1 0 Output 5 C
36. ntions in the Before You Start section there will be no red exclamation points adjacent to these grids DEM soil AWC precipitation etc However if your grids are named differently the first step will be to assign names to these existing grids Below is an example for assigning a name to the DEM erid e Right click on the red exclamation point adjacent to DEM in the Table of Contents and select Properties EI DEM slop9 asp12 Aspect Slope DEM Page 3 In the Layer Properties window that opens select Set Data Source General Source Extent Display Symbology Joins amp Relates Property E Raster Information Columns and Rows Number of Bands Cellsize X Y Uncompressed Size Format Source Type Pixel Type Pixel Depth Data Source Folder Raster File System Raster C WBYDEM DEM Set Data Source Click Add then OK Layer Properties General 9 Ra TEE Proper Look in aj aw Show of type Raster datasets v DK Cancel Browse to and select the DEM for your study area In this example C WB DEM dem_scbi Cancel et Data 5ource dem scbi OK Cancel Repeat these procedures for any unassigned existing grids DEM Slope Aspect Monthly Temperature Precipitation Radiation and Soil AWC Page 4 Zoom to Full Extent amp Set Data Frame Coordinate
37. onments lt lt Hide Help Tool Help e Use the dropdown menu to specify the Soil Available Water Capacity grid soil awc mm in this example Soil AWC cnil Available Water Capacity mm Gtnranet amp T nd rl e Click OK Page 27 e Upon completion monthly Storage First Full and Storage equals AWC grids are added to the Table of Contents These serve as input grids for the next model Surplus EI ST 1st Full ST eq AWC 12 O ST eq AWC 11 O ST eg AWC 10 O ST eq AWC 09 ST eq AWC 08 ST eq AWC 07 ST eg AWC 06 ST eg AWC 05 ST eg AWC 04 ST eg AWC 03 ST eg AWC 02 L ST eg AWC 01 STistFull 12 STistFull 11 O STistFull 10 O STistFull 09 O STistFull 08 LJ STistFull 07 STistFull 06 O STlstFull 05 O STistFull 04 STistFull 03 STistFull 02 O STistFull 01 C Surplus Computes monthly surplus OK e Double click the C Surplus model may take a moment to load then click Precipitation 01 C Surplus Climate Precipiprecip mm 01 Precipitation 02 Computes monthly and annual Climate Precip precip mm_02 D Surplus mm Precipitation 03 a Climate Precipiprecip mm 03 Precipitation 04 Climate Precipiprecip mm 04 Precipitation 05 a Climate Precip precip mm_05 v Precipitation 06 a Climate Precipiprecip mm 06 Precipitation 07 a Climate Precipiprecip mm 07 Precipitation 08 n a
38. precipitation grids Spatial Analyst Tools Math Plus b As another alternative gridded climatic data for the US is also available from PRISM ModelBuilder may be useful to automate these repetitive steps 1 You will need to clip the monthly climate grids to your study area Analysis Tools Extract Clip It may be advisable to buffer your study area to create a larger clip to insure complete coverage at the end of the processing steps Analysis Tools Proximity Buffer 11 PRISM grids are integer with units x 100 Therefore 1 The integer PRISM grids will need to be converted to floating point Spatial Analyst Tools Math Float 2 The resultant grids will then need to be divided by 100 Spatial Analyst Tools Math Divide 111 The relatively coarse resolution climate grids can then be set to the resolution of your DEM Data Management Tools Raster Raster Processing Resample iv This final fine resolution climate grid can be clipped to your actual study area boundary as opposed to a buffered study area Page 33 Appendix B Procedure used for computing PET adjustment coefficients Hourly solar radiation was computed for 2 days each month two week intervals from April September using the ArcGIS Solar Radiation toolset PET was then computed for each day using hourly temperature as well as a single average daily temperature value for each hour Hourly temperature data were from
39. puts e Reclassed slope and aspect grid from above o DEMislop9 aspl2 e Remap tables with PET Adjustment Coefficients growing season months 04 09 o example CAWBWPET CoeffsiPET Adj 4IN 04 rmp Output e Monthly PET Coefficients growing season months 04 09 o example CAWBWPETWPET coef 04 C PET Adjust Inputs e Monthly PET grids PET growing season months 04 09 o example PETWpet 04 e Monthly PET Coefficients from above o example PETPET coef 04 Output e Monthly Adjusted PET mm growing season months 04 09 o example C AWBWPET Wet adj 04 Page 35 2 P PE A P PE Inputs e Average monthly precipitation mm o example ClimatelPrecipiprecip mm 01 e Monthly PET grids PET ZZ or Adjusted PET grids pet adj ff o example PETPET 01 or PET Wet adj 04 Output e Monthly P PE grids P PE 7 in mm o example C WB P PE P PE_01 e Daily P PE grids Daily P PE 7 in mm o example C WB P PE Daily_P PE_01 e Annual PET mm o example C WB PET pet_annual 3 Storage A Storage Inputs e Number of days in the current month 01 Jan 31 09 Sep 30 02 Feb 28 10 Oct 31 03 Mar 31 11 Nov 30 04 Apr 30 12 Dec 31 Soil AWC grid SoiNsoil awc mm P PE grid P PEW pe for current month mm Daily P PE grid P PENDaily p pe 77 for current month mm Storage for the previous month ST Z in mm NOTE for first month run 1 e the month where Storage come full use the AWC grid SoiNsoil awc
40. reviously using the Radiation gt PET tool EI PET pet annual pet adj 09 pet adj 08 pet adj 07 pet adj 06 pet adj 05 pet adj 04 PET coef 09 LJ PET coef 08 PET coef 07 LJ PET coef 06 PET coef 05 LJ PET coef 04 OO pet 1 pet 11 pet 10 pet 09 pet 08 pet 07 OO pet 06 OO pet 05 pet 04 pet 03 pet 02 OO pet 01 C PET Adjust e Double click on the model C PET Adjust e Click OK to perform the topographic adjustment to monthly PET erids Apri PET 04 C PET Adjust May PET 05 Creates Adjusted PET grids for PET pet 05 growing season months April June PET 06 September using original PET grids PW aa s and PET Adjustment Coefficient grids July PET 07 PET pet 07 August PET 08 PETvpet 08 v September PET 09 3 PETvpet 09 v April PET Coefficient 04 PETYPET coef 04 v May PET Coefficient 05 PETYPET coef 05 v June PET Coefficient 06 PETYPET coef 06 z July PET Coefficient 07 PETYPET coef 07 v August PET Coefficient 08 PETYPET coef 08 hr September PET Coefficient 09 PETYPET coef 09 v April Adjusted PET 04 CAWBIPETipet adj 04 May Adjusted PET 05 CAWBAPETipet adj 05 Cancel Environments lt lt Hide Help Tool Help Page 13 e Upon completion Adjusted PET grids pet adj 04 09 are added to the Table of Contents G
41. ring the growing season defined as April September Users in the southern hemisphere or in climates with a year round growing season will need to adjust the methodology accordingly This toolset is optional for completing the water balance analysis but it attempts to account for important temperature changes throughout the day With a monthly time step there is no diurnal variation in temperature and so maximum PET occurs on southern exposures since that is where maximum insolation occurs PET is then symmetrical about the N S axis This toolset employs adjustment coefficients that either increase or decrease PET based on topographic position The first step in creating PET adjustment coefficients therefore 1s to create a topographic grid based on the existing slope and aspect grids for the study area PET Adjustment Coefficients were computed for 4 sites in the northern hemisphere eastern U S and can be used as models for other study areas e Williamsport PA 41 N e Elkins WV 39 N e Beckley WV 37 N e Asheville NC 35 N These were created using Typical Meteorological Year data published by the National Solar Radiation Database In the tables below the amount of increase gt 1 or decrease lt 1 to PET values based on topographic position can be observed for each of these sites Page 9 PET adjustment coefficients for the entire growing season standardized so that flat sites 0 1 slope have a value of 1
42. roblem since these grids worked with the one check AET occurs in both checks e Zoom into non zero areas See if a discernible pattern is evident that matches any of your input grids e g Soil AWC this could indicate the problem e Use your Identify tool to click on a single cell in the problem area and ascertain the values of all input grids See if you can determine where the error has arisen An Excel spreadsheet that computes the water balance is available on the Water Balance Toolbox for ArcGIS web page which may help in diagnosing individual cells Clean Up File Maintenance You will likely want to save your original input grids Temperature Precipitation Radiation Soil Available Water Capacity DEM as well as the key water balance grids PET Storage AET Deficit and Surplus However many of the grids created with the Water Balance tool are intermediate only necessary as input for various models These can be deleted to save disk space once you are sure your checks hold from Step 5 Save and close your ArcGIS project then you can delete the following folders in C WB Checks subfolder Temp Factors in Climate folder P PE If you are not interested in soil moisture storage grids you can delete the entire Storage folder Otherwise use ArcCatalog to delete all of the grids except ST_ grids in the Storage folder If you open your saved Water Balance mxd project after performing the delet
43. ta ST 01 E Storage st 12 m ce 11 Page 24 4 AET Computes actual evapotranspiration deficit and surplus Celta Storage 01 A AET Delta STXDelta ST 01 Delta Storage 02 Delta ST Delta ST 02 Celta Storage 03 Delta ST Delta 5T 03 Celta Storage 04 Delta STXDelta 5T 04 Celta Storage 05 Delta STXDelta ST 05 Celta Storage 06 Delta STXDelta ST 06 Delta Storage OF Delta STXDelta ST 07 Celta Storage 05 Delta STXDelta ST 08 Celta Storage 09 Delta STXDelta ST 09 Celta Storage 10 Delta STADelta ST 10 Celta Storage 11 Delta STXDelta ST 11 Delta Storage 12 Delta_ST Delta_ST_12 Precipitation 01 Computes monthly and annual actual evapotranspiration and deficit 111 Climate Precipiprecip mm 01 Precipitation 02 Climate Precipiprecip mm 02 Precipitation D3 ClimatekPrecip precip mm 03 Precipitation 04 amp v v lel lel W a v v Le v v amp W W Climate Precipiprecip mm 04 Frecioitation 05 2 Cancel Environments lt lt Hide Help Tool Help Page 25 e Upon completion AET and Deficit grids are added to the Table of Contents Ei Iv Deficit Def Annual def 12 def 11 def 10 def 09 def 08 def 07 def 06 def 05 def 04 def 03 def 02 def 01 LIEJETEIEJ EI EH EJ E ET ET ET ET AET Annual aet 12 aet 11 aet 10 aet 09 aet 08 aet 07 aet 06 aet 5 aet 04 aet 05
44. tes the first monthly Storage grid is added to the Table of Contents st 04 in this example m Storage Cy st 12 st 11 CI st 10 Ct st 09 C st 08 Ly st 07 CI st 06 J st 05 st 04 st 03 st 02 st 01 Page 19 e When running the Storage model for subsequent months select the previous Storage grid from the dropdown list In this example for May month 05 st 04 is selected as the Previous Storage grid from the dropdown list ye A storage days in month 31 F PE arid For current month P PE p ne 05 Daily P FE For current month P PEtDaily P PE 05 5 Storage For current month Previous Storage oll vy soil awc mm 5 OK Cancel Environments lt lt Hide Help Tool Help A Storage start in month where Storage Is assumed full ST AVVC 1e the first month after winterfspring recharge in which some grid cells in the P PE grid take on a negative value Model computes soil moisture storage monthly value based on the last day of the month Uses daily time step assuming decreasing availability of sail moisture Mather 1974 curve C WATBUG default e Continuing to use the example above P PE is negative through August month 08 so we would continue to run model consecutively for each of these months for example June de A storage days in month 30 P PE grid For current month P PE p pe 06 Daily P FE Far current month P PEADaily
45. them to the C WB DEM folder Page 1 e Monthly temperature C and precipitation mm grids and an annual precipitation grid o Copy these climate grids to C WB Climate o The monthly grids will be named temp c 01 temp c 12 and precip mm Ol precip mm 12 when running the Water Balance model The annual precipitation grid will be designated precip mm 15 If you do not have an annual precipitation grid follow these steps to create one Double click on Cell Statistics tool Spatial Analyst Tools Local Cell Statistics Cell Statistics Input rasters or constant values i Output raster z FH AB Spatial Analyst Tools The raster to be created i m l 7 ClimatelPrecipiprecip mm 01 i H S Conditional 7 ClimatelPrecipiprecip mm 02 i i M 7 ClimateiPrecipiprecip mm 03 E Density 7 ClimateiPrecipiprecip mm 04 X i 53 7 ClimatelPrecipiprecip mm 05 3 i m4 Distance 7 ClimatelPrecipiprecip mm 06 t i 7 ClimatelPrecipiprecip mm 07 amp Extraction 7 ClimatelPreciplprecip mm 08 Ed Generalization 7 ClimatelPrecipiprecip mm 09 i i 7 ClimateiPrecipiprecip mm 10 DE Groundwater 4 Output raster oe Hydrolo H amp y gy C WB Climateiprecip mm_13 j EE Interpolation Overlay statistic optiona B4 Local SN e Jo Cell Statistics W 4 Cancel Environments lt lt Hide Help Tool Help Use the dropdown to select the 12 monthly precipitation gri
Download Pdf Manuals
Related Search