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Watershed Modeling - The University of Texas at Dallas

1. 2 Select Global Projection DEM Delineation 1 5 3 Select Set Projection 4 Set the Projection to UTM Datum to NAD 27 Planar Units to METERS and Zone to 12 114 W 108 W Northern Hemisphere 5 Select OK 6 Set Vertical Units to Meters 7 Select OK 8 Under Project Boundary select Define 9 Inthe Microsoft Virtual Earth Map Locator window enter a latitude of 38 6469 and a longitude of 112 4291 and click jump to location 10 Zoom in until the Virtual Earth window looks similar to Figure 1 3 and then click OK Virtual Earth Map Locator Map Style Map Options Jump Map Location Map Controls Lett zm Right Zoom Latitude 38 6479807929779 Longitude 112 42755889892 Pan Sulphurdale Microsoft Virtual Earth Figure 1 3 Project Bounds in Virtual Earth 11 Click Next gt to advance to the next step 1 3 3 Download Watershed Data from Web Services 1 Select Web Services as the data source 2 Click Next gt to advance to the next step 1 6 WMS Tutorials Volume 2 1 3 4 3 In the Data Type column of the Web Services spreadsheet toggle on the option for TerraServer aerial photo 4 Click the Browse button next to TerraServer aerial photo 5 Name the file wizphoto jpg and click Save 6 In the Data Type column of the Web Services spreadsheet toggle on the option for TerraServer topo 7 Click the Browse button next to TerraServer topo 8
2. At this point the study area appears as a small polygon You will zoom in to better distinguish the area 3 Choose the Zoom tool X 4 Zoomin on the region indicated in Figure 7 2 Figure 7 2 Zoom in on the watershed 5 Right click on DEM in the Project Explorer and select Display Options 9 6 Choose DEM Data 7 Toggle off the check box for displaying DEM Contours 8 Select OK 9 Right click on Drainage coverage and select Compute Basin Data 7 6 WMS Tutorials Volume 2 10 Select the Current Coordinates button 11 Select Global Projection 12 Select Set Projection 13 Ensure Meters are selected in the Planar Units drop down box 14 Select OK 15 Ensure Meters are selected as the vertical units 16 Select OK twice 7 4 3 Running NSS 1 Switch to the Hydrologic Modeling module amp 2 Make sure Model combo box is set to NSS 3 Choose the Select Basin tool N 4 Double click on the icon for Basin 1B 5 Select Yes Notice that the regression equation is automatically selected Also if our basin had overlapped with another NSS region the areas and percentages of overlap for each region would also have been calculated 6 Enter 10 8 for the Lake Area variable 7 Select the Compute Results button 8 Select Done As you can see the NSS Region coverage allows WMS to automatically load the appropriate regression equation s when we open the NSS dialog However this might not save us a great deal of ti
3. 1 8 WMS Tutorials Volume 2 Figure 1 5 Drainage Outlet Location 4 Click Next gt to advance to the next step 5 Enter a stream threshold value of 1 00 mi 2 and the Computation Units at their default values 6 Select Delineate Watershed When you select Delineate Watershed WMS converts the DEM streams to feature arcs defines the basin boundary and computes basin related data including basin area average basin slope mean basin elevation and time of concentration 7 Click Next gt to advance to the next step 1 3 6 Create Sub basins Since we won t be setting up a hydrologic model in this exercise we don t need to complete the rest of the steps in the wizard However we would like to go back and create sub basins 1 In the list box on the left side of the wizard window select the heading Choose Outlet Locations 2 Zoom in around the area shown in Figure 1 6 DEM Delineation 1 9 Figure 1 6 Zoom Area 3 Choose the Create Outlet Point tool from the wizard window 0 4 Create another outlet at the location shown in Figure 1 7 just below the stream junction Ye J Figure 1 7 Node Location ISen 5 Choose the Frame macro ka 6 Zoom in around the branch shown in Figure 1 8 1 10 WMS Tutorials Volume 2 NAR oy hy a i ig Ean T CS MaE NN D fi aN Figure 1 8 Zoom Area 7 Choose the Create Outlet Poi
4. 12 Toggle on the Display of Transform methods and Show SCS 13 For each basin choose the Define button under Compute Basin Data and define the equation and use the Compute Lag Time computation method with the SCS Method You should now have a computed lag time for each basin all about 1 hour 14 Select OK Setting up the Routing Parameters If you were to run HEC HMS right now you can if you want you would see that the hydrographs from the upper basins would be combined with the lower basin hydrograph at the watershed outlet without any lag or attenuation because you have not yet set the routing parameters You will now define a routing method which will instruct HEC HMS to compute lag and attenuation on the upper basin hydrographs before adding them to the lower hydrograph Routing for a reach is always defined at the upstream outlet of the reach in WMS 5 18 WMS Tutorials Volume 2 11 15 16 17 10 12 13 14 Select the Select Outlet tool amp Double click on the outlet the yellow circle icon of the upper right basin Make sure the Type field at the top left of the dialog is set to Reaches Set the Show option to Selected again Toggle on the Display of Method and Show Muskingum Cunge Std Change the Routing Method to Muskingum Cunge Set the bottom width field to be 5 five feet wide Set the side slope value to be 1 1 1 side slope Set the Manning s roughness N to be 0 05
5. Bare Ground The landuse shapefile in this project also contains landuse polygons for residential areas with an ID for 11 Complete the land use table by editing the file 4 Add the following line to the file 71 Residential 61 75 83 87 5 Save the file and close the editor 3 10 2 Computing Composite Curve Numbers In order to compute composite curve numbers WMS needs to know which type of soil underlies each area of land You will need either a landuse and soil 3 14 WMS Tutorials Volume 2 type coverage or a landuse and soil type shapefile with the appropriate fields For this exercise we will be using landuse and soil type shapefiles 1 Select Calculators Compute GIS Attributes 2 Make sure the SCS Curve Numbers option is selected in the Computation section of the dialog 3 Select GIS Layers in the Using section of the dialog 4 Select the Soil Layer Name to be soils_poly shp 5 Make sure the Soil Group Field has been set to HYDGRP 6 Select the Land Use Layer Name to be landuse_poly shp 7 Make sure the Land Use ID Field has been set to LU_CODE You may have your land use and soil type tables stored in data files such as the one you previously edited Instead of manually assigning the data as you have here you would read these tables in from this dialog using the Import button Whether you have manually created tables or read them in from files you should see the land use IDs and CNs for each soil type
6. 17 Set the Weir length to 20 feet 18 Set the Weir elevation to 25 feet 19 Select OK four times to return to the WMS window You have now defined a detention facility that has a standpipe and a spillway for control structures The incoming hydrograph to this outlet point will be routed through the detention facility before being routed downstream and combined with the hydrographs of other basins 20 Select the bottom most outlet point 21 Select the Compute Hydrographs button in the Outlet column 22 Choose the Route by summing method 23 Choose Universal hydrograph method 24 Select Done 25 Select OK 26 Double click on the hydrograph box for the bottom most outlet 6 4 Conclusion In this exercise you have learned some of the options available for using the rational method in WMS You will want to continue experimenting with the different options so that you can become familiar with all the capabilities in WMS for doing Rational Method simulations CHAPTER 7 National Streamflow Statistics Program NSS Interface The National Streamflow Statistics program developed by the USGS provides a quick and easy way of estimating peak flows for ungaged watersheds This data can be used in the design of culverts flood control structures and flood plain management It utilizes regression equations that have been developed for each state Most regression equations are functions of parameters such as area slope and runoff distan
7. 3 Open statsgo shp 4 Right click on statsgo shp layer in the Project Explorer 5 Select Open Attribute Table Notice that the table has three fields named AREA PERIMETER and MUID 6 Select OK 4 2 3 Join Soils Database File Table to Shapefile Table 1 Right click on statsgo shp in the Project Explorer 2 Select Join Table to Layer 3 Open statsgoc dbf 4 Ensure that Shapefile Join Field and Table Join Field are both set to MUID 5 Change the Table Data Field to HYDGRP 6 Select OK 7 Right click on statsgo shp in the Project Explorer 8 Select Open Attribute Table Notice that the HYDGRP field is now a part of the shapefile 9 Select OK 4 2 4 Convert Soil Shapefile Data to Feature Objects 1 Choose the Select Shapes tool k 2 Draw a selection box around the DEM extents 3 Select Mapping Shapes gt Feature Objects 4 Select Next This window shows all of the attribute fields in the soils shape file Because this file was derived from a standard NRCS statsgo file you will notice that the hydrologic soil groups field is named HYDGRP and so WMS will automatically map this to be the soil type If the attribute field were named 4 4 WMS Tutorials Volume 2 anything other than HYDGRP then you would have to manually map it using the drop down list in the spreadsheet J 6 7 8 Make sure the HYDGRP field is mapped to the SCS soil type attribute Select Next Select Finish Clear the selected polygo
8. Next Next and Finish to set up the simulation run 12 Select Compute Select Run Select Run CCTribRoute 1 13 Select Compute Compute Run CCTribRoute 1 or the Compute 75 Current Run macro 14 When finished computing select Close 15 Select different elements basins junctions reaches and view results 16 Select Results Global Summary Table and explore 17 Select Results Element Graph and explore 18 Select Results Element Summary Table and explore 19 Select Results Element Time Series Table and explore You may continue to explore the HEC HMS input parameters passed from WMS and computed results or any other options 20 When finished close the Global and Element summary tables and graph windows and exit HEC HMS by selecting File Exit 21 Select Yes when prompted to save the project 5 20 WMS Tutorials Volume 2 5 6 Modeling a Reservoir in HEC HMS 5 6 1 5 6 2 There is an existing small reservoir at the outlet of the upper left basin It has a storage capacity of 1000 ac ft at the spillway level and 1540 ac ft at the dam crest Defining a Reservoir in Combination with Routing One of the routing methods available in HEC HMS is Storage routing which can be used to define reservoir routing However in this case we are already using Muskingum Cunge routing to move the hydrograph through the reach connecting the upper left basin to the watershed outlet so we must define the outlet as a reservoir so t
9. and land use descriptions in the window of the Mapping section 8 Select the Import button near the bottom of the dialog 9 Find and open the mapping table anduse tbl You should now see the assignment of CN values for the land use table previously edited 10 Select OK to compute the composite CNs A Runoff Curve Number Report is generated and opened automatically The composite curve number appears at the bottom of the report 11 Select the Select Basin tool M 12 Double click on the basin Notice that the Curve number edit field has been updated with the calculated value from the Compute GIS Attributes dialog Time of Concentration Calculations and Computing a Composite CN 3 15 3 11 More TR 55 While you were entering the data for the basin you may have noticed that instructions are given in the TR 55 data window to let you know what must be entered before a peak Q can be determined Once you enter all of the data the peak Q is computed and displayed in the same window You can also get help for anything listed in the window 1 3 12 Conclusion Notice that the TR 55 reference equation for computing peak flow is displayed next to Peak Discharge Select the Compute Hydrograph s button Select OK to close the TR 55 dialog Choose the Select Hydrograph tool Double click on the hydrograph icon that is displayed by the upper basin to view the hydrograph in a separate window This completes the chapter on using t
10. this is fairly rough but we want to exaggerate the routing effects for this exercise Select OK Double click on the outlet of the upper left basin Make sure the Type field at the top left of the dialog is set to Reaches Change the Routing Method to Muskingum Cunge Set the bottom width field to be 5 five feet wide Set the side slope value to be 1 1 1 side slope Set the Manning s roughness N to be 0 05 this is fairly rough but we want to exaggerate the routing effects for this exercise Select OK 5 5 4 Running HEC HMS You now have everything defined to run a three basin HEC HMS analysis that includes routing the upper basins through the reaches connecting them to the watershed outlet 1 2 3 Right click on Drainage Coverage Tree in the Project Explorer and select Save HMS File Name the HMS project file CCTribRoute and Save Start HEC HMS on your computer HEC HMS Interface 5 19 4 Select File Open 5 Select the Browse button and browse to the location where you just saved your HMS Project from WMS by default this will be in the hec 1 directory of your tutorial files 6 Select the CCTribRoute hms project file 7 From the HEC HMS project explorer expand the Basin Models Meteorologic Models and Control Specifications folders 8 Expand the Clear Creek Tributary basin model and then select it 9 Select Compute Create Simulation Run 10 Change the Run Name to CCTribRoute 1 11 Click Next
11. 12 114 W 108 W Northern Hemisphere Select OK Set vertical units to Meters Select OK to convert the data Since we will not be using them until later hide the Land Use and Soil Type coverages by toggling off their check boxes in the Project Explorer Select the Drainage coverage from the Project Explorer to make sure it is the active coverage 5 2 7 Delineate the Watershed 1 2 Select the Drainage module 8 Select the Frame macro 4 Select DEM Compute TOPAZ Flow Data Select OK Select OK in the Units dialog Select Close once TOPAZ finishes running you may have to wait a few seconds to a minute or so Select the Zoom tool X Zoom in by dragging a box as illustrated in Figure 4 1 5 6 WMS Tutorials Volume 2 RER Se a ky OSS x ER an MENEE A i Figure 5 1 Zoom in on the area bounded by the rectangle above 9 Select the Create Outlet Point tool O 10 Create a new outlet point where the tributary you just zoomed in on separates from the main stream as illustrated by the arrow in Figure 4 1 Make certain that the outlet point is on the tributary and not part of the main stream Also the outlet needs to be inside one of the flow accumulation blue cells WMS will move the outlet to the nearest flow accumulation cell if you do not click right in one of the flow accumulations cells 11 Select the Frame macro 4 12 Select DEM Delineate Basins Wizar
12. 4 2 Running HEC HMS You can now run another simulation to compare the results with the modified CN value 1 Right click on Drainage Coverage Tree in the Project Explorer and select Save HMS File 2 Name the HMS project file CCTribCN and Save 3 Start HEC HMS on your computer 4 Select File Open 5 Select the Browse button and browse to the location where you just saved your HMS Project from WMS by default this will be in the hec 1 directory of your tutorial files 6 Select the CCTribCN hms project file 7 From the HEC HMS project explorer expand the Basin Models Meteorologic Models and Control Specifications folders 8 Expand the Clear Creek Tributary basin model and then select it 9 Select Compute Create Simulation Run 10 Change the Run Name to CCTribCN 1 11 Click Next Next Next and Finish to set up the Run 12 Select Compute Select Run Select Run CCTribCN 1 13 Select Compute Compute Run CCTribCN 1 or the Compute Current Run macro xs 14 When finished computing select Close 15 Select the CCTrib basin under the Clear Creek Tributary basin model from the HEC HMS project explorer 16 Select Results Global Summary Table and explore 17 Select Results Element Graph and explore 18 Select Results Element Summary Table and explore 19 Select Results Element Time Series Table and explore 5 14 WMS Tutorials Volume 2 You may continue to explore the HEC HMS input parameters passed from WMS an
13. Data Select OK You can see that the drainage along the road has now been diverted into the original basin as shown in Figure 2 10 Editing DEMs 2 13 soa a 4 z A aD na Figure 2 10 New basin including road stream arcs 2 4 Editing Flow Directions Flow directions can be inaccurate due to imprecision in the DEM The flow direction for each DEM point can be manually edited in order to improve accuracy in basin delineation or creation of stream arcs Notice that the flow accumulations show a stream that differs from the stream shown in the background image in Figure 2 11 2 14 WMS Tutorials Volume 2 Figure 2 11 Stream path differences 2 4 1 Edit Flow Directions for DEM Points Correct the flow directions for each of the numbered DEM cells in Figure 2 12 1 Switch to the Terrain Data module 2 Zoom in to see the area shown in Figure 2 12 Editing DEMs 2 15 Figure 2 12 Edit flow directions for the numbered DEM cells 3 Use the Select DEM Points tool and double click on a numbered cell shown in Figure 2 12 This will bring up the DEM Point Attributes dialog shown in Figure 2 13 DEM Point Attributes Attributes Elevation 2049 4646 I Depression point Basin NONE Outlet NO Stream NO Flow accumulation 0 26 sq mi 743 cells Flow distance to outlet Figure 2 13 DEM Point Attributes dialog 4 Change the flow direction according to Table 2 1 2 16 WMS Tutorial
14. Explorer 2 Select New Coverage 3 Change the coverage type to Land Use 4 Select OK 3 4 WMS Tutorials Volume 2 5 Right click on GIS layers and select Add Shapefile Data 6 Open valdosta shp and make it the active layer This land use shapefile was obtained from www webgis com but the EPA and other websites contain similar information Alternatively we could have digitized land use polygons from an image discussed in Volume 1 Chapter 3 Basic Feature Objects 7 Choose the Select Shapes tool k 8 Drag a selection box around the drainage basin polygon 9 Select Mapping Shapes gt Feature Objects 10 Select Next 11 The LUCODE with the land use ID is automatically mapped so you can continue by selecting Next LJ cv ovau vad 12 Select Finish 3M GIS Layers valdosta shp 13 Hide valdosta shp by toggling off its check box in the Project Explorer ME you may need to expand the GIS Layers folder to see it Only the portion of the shapefile that was selected will be used to create polygons in the Land Use coverage The following figure displays the resulting land use polygons and their respective land use codes This land use classification is consistent among all of the USGS land use data were codes from 10 19 are urban 20 29 agricultural etc A complete listing of code values can be found in the WMS Help file Time of Concentration Calculations and Computing a Composite CN 3 5 Legend LU_CODE ffa 11 Resident
15. HMS Meteorological Parameters 2 Set the Precipitation Method to SCS Hypothetical Storm 3 Set the Storm Selection to Type IT 4 Set the Storm Depth to 8 inches 5 Select OK Setting up the Basin Data Parameters In the first simulation you will treat the entire watershed as a single basin 1 Select the Select Basin tool M 2 Double click on the brown basin icon labeled 1B Double clicking on a basin or outlet icon always brings up the parameter editor dialog for the current model in this case HEC HMS 3 Notice that the area has been calculated in this case in sq miles because we are performing calculations in English units 4 Change the name to CCTrib 5 Enter Main Branch in the description HEC HMS Interface 5 9 Displaying and Showing options allows you to see only those variables for which you wish to enter data For example in this case toggling on the Loss Rate Method allows you to pick which method you want to use in this case the method we want is the default You then toggle the display for the different parameters associated with a given methodology from the show column In our case we can now see in the Properties window the Loss Rate Method and the parameters for the SCS Curve Number method The HMS Properties window is versatile in that it allows you to see properties for all or selected basins junctions reaches reservoirs etc 6 Toggle on the Display of the Loss Rate Method option 7
16. Set the side slope value Z to be 1 1 1 side slope 7 Set the Manning s roughness N to be 0 05 this is fairly rough but we want to exaggerate the routing effects for this exercise 8 Select OK ches 9 Select Done 10 Double click on the outlet of the upper left basin 11 Select the Routing Data button 12 Select the Muskingum Cunge method for routing 13 Set the width WD field to be 5 14 Set the side slope value Z to be 1 15 Set the Manning s roughness N to be 0 05 16 Select OK 17 Select Done 4 5 4 Running HEC 1 You now have everything defined to run a three basin HEC 1 analysis that includes routing the upper basins through the reaches connecting them to the watershed outlet 1 Select HEC 1 Run Simulation 4 18 WMS Tutorials Volume 2 2 Click the browse button next to the Input File 3 For the file name enter Routing and click Save this specifies the file name but does not actually save it 4 Verify that the Save file before run is toggled on 5 Select OK 6 Select Close once HEC 1 finishes running you may have to wait a few seconds to a minute or so 7 While holding the SHIFT key down select all of the hydrograph icons double clicking on the last one so that all hydrographs are drawn in the same plot window 8 Close the plot window by selecting the X in the upper right corner 4 6 Modeling a Reservoir in HEC 1 4 6 1 4 6 2 There is an existing small reservoir at t
17. THE WATERSHED ccccecessessececececeessnaececececsescaececececsensaaeseccceceesesaesesececeessaaseecececeeees 5 2 5 3 SINGLE BASN ANALYSIS 033i Secciecacectcedenceteotedaceuedundenceiecedeasscutea weadessvecueed cgaveguedeueecedcpeds duvets ebeaceseeedeeats 5 7 5 4 COMPUTING THE CN USING LAND USE AND SOILS DATA cccccccccceesessaeceeececsesseaeceeececsessaseeeeeeees 5 12 5 5 ADDING SUB BASINS AND ROUTING cccccccccecececececececececececececececececececececeeseececececeeseeeseeceseeseeeeeeeecess 5 14 5 6 MODELING A RESERVOIR IN HEC HMS uuu ecccececececccccccececececececececececececececececececececeescececececececececesesess 5 20 5 7 OINO B OKY CE IN EEEE EEE E E AESA AE NEES EEEE EEE ee EE 5 23 RATIONAL METHOD INTERFACE eeesseeessseessoceessoceesseceeseeosscoeessoceesseceessecsssoeesseceesseceecoeesseseessoceessese 6 1 6 1 READING IN TERRAIN DATA n a roaraa a ae eoa eieo areae e o arodes 6 1 6 2 RUNNING A RATIONAL METHOD SIMULATION ccccccccecececececececececececececececececececececececececececececececeeess 6 2 6 3 ADDING A DETENTION BASIN ccccccecececececececececececececececececececececececececececececececececececececececececececececececs 6 10 6 4 CONCLUSION Sesinin feted cnt dedetulcextasdecedddodudeteSendede duanse etovieted e e aa a e a 6 11 NATIONAL STREAMFLOW STATISTICS PROGRAM NSS INTERFACE esseeeesseosscseessocecssese 7 1 7 1 DATACOLLECTION asninn nias i a a a a n a a n ee 7 1 7 2 BASIN DELINEATION AEE E E
18. VOLUME 76123 47 a 60 5 Dn ge 2a ras Figure 6 3 Rational Method Hydrograph for a Basin 7 When you are finished viewing the hydrograph close the plot window by selecting the X in the upper right corner of the window Defining Rainfall Intensities at the Outlet to Compute Runoff Hydrographs WMS can determine composite rational method parameters at the outlet for computing hydrographs The time of concentration at an outlet point is defined as the longest flow time from upstream basins times of concentration combined with any lag times from channels The area is the cumulative upstream area and the runoff coefficient is determined as an area weighted value from the upstream basins With the time of concentration at the outlet defined you will need to determine the appropriate rainfall intensity In order for WMS to compute peak flows and hydrographs at outlets you will need to define the travel time between outlets and the intensities for the time of concentration at each outlet 1 Select the Select Outlet tool Q 2 Double click the outlet icon of Upper as shown in Figure 6 1 be sure to select the circular outlet icon and not the square basin icon You will note in the Outlet portion of the Rational Method dialog that information upstream from this outlet has been aggregated in the case though there is just one basin upstream The longest flow time is listed for the time of concentration a cumulative a
19. Verify that the Save file before run is toggled on 4 22 WMS Tutorials Volume 2 Select OK Ensure that Read solution on exit is selected and select Close once HEC 1 finishes running you may have to wait a few seconds to a minute or so After HEC 1 runs you can open any or multiple within the same plot window by holding down the SHIFT key to multi select of the hydrographs by double clicking on the corresponding icon Close all plot windows before moving on 4 7 Reviewing Output It should be emphasized here that while WMS makes it easy to set up a HEC 1 model and compute a result it is not a substitute for understanding the basic theory and equations used in HEC 1 You are encouraged to read the HEC 1 manual found in the documents directory distributed with WMS and other texts on hydrologic modeling You are also encouraged to review the HEC 1 output file that is generated with each simulation in order to glean more understanding about how your model is working 1 2 4 8 Conclusion Select File Edit File Find and open the file named reservoir out Select OK to open the file with Notepad Scroll through this file and examine what information HEC 1 saves to the output file If you have errors running HEC 1 simulations you may often find the answer to the problem within the out output file This concludes the exercise defining HEC 1 files and displaying hydrographs The concepts learned include the followin
20. WMS Select File Open Locate the folder C Program Files WMS8I tutorial demdelin Open josephpeak dem In the Importing USGS DEMs dialog click the Add button Add the following three DEMs remember that you can hold the CTRL key down and add more than one at once or use the Add button to add each additional one before selecting OK e marysvalecanyon dem e redridge dem e trailmountain dem Enter a thinning factor of 3 in the Thinning factor edit field Thinning the resolution of the DEMs will reduce the density of elevation points so that your computer will process the DEM data faster The resolution of points in the 30 meter DEMs is too dense for the purposes of this exercise so you will not lose any accuracy by thinning 9 Select OK 1 2 1 Trimming the DEM 1 2 Select DEM Trim Polygon Select the Enter a polygon interactively option Select OK Trace around the area formed by the polygon shown in Figure 1 1 clicking on each corner and double clicking to end Select the Frame macro ad DEM Delineation 1 3 Figure 1 1 DEM Trim Area 6 Right click on DEM under Terrain Data in the Project Explorer and select Fill to linearly interpolate and fill gaps that were created by thinning the DEM data 1 3 Watershed Delineation using the Hydrologic Modeling Wizard Now that we ve imported a DEM we can launch the Hydrologic Modeling Wizard to guide us through the process of watershed deli
21. Yo ound E E E E E 7 2 7 3 RUNNING NS So fnna a a RL Re Re ahi 7 2 7 4 UTILIZING AN NSS REGION COVERAGE ccccccccecececececececececececececececececececececececececececececececececececececesess 7 3 7 5 CGONGLUSIONS EET EE ETE EAEE PE E ETE EE E EET EE E EE E ETE 7 6 CHAPTER 1 DEM Delineation Watershed delineation from DEM s is straightforward and relatively simple provided the project area is not entirely flat or completely dominated by man made structures you cannot expect the DEM method to work if there is no relief in the DEM elevations themselves This exercise teaches DEM delineation using the hydrologic modeling wizard a step by step delineation approach that makes the process even simpler 1 1 Objectives In this exercise you will learn the basics of DEM delineation using the hydrologic modeling wizard This includes the following 1 Importing DEM Data 2 Computing flow paths and flow accumulations 3 Delineating watersheds from DEMs 4 Delineating sub basins within a watershed 1 2 Importing DEM Data The first step in delineating a watershed is to import one or more DEMs Though DEM retrieval will be automated through the hydrologic modeling wizard at some point in the future for this exercise we will import the DEM data manually 1 2 WMS Tutorials Volume 2 To read in a set of four 30 meter DEMs from the 1 24000 series complete the following steps 1 2 8 Close all instances of WMS Open
22. a guide while defining the equations 3 10 WMS Tutorials Volume 2 DA Figure 3 4 Time Computation Arcs 1 Switch to the Time Computation coverage 2 Choose the Select Feature Arc tool K 3 Double click on the arc labeled A in Figure 3 4 By default the arc will be a TR 55 sheet flow equation arc so all you need to do is define the overland Manning s roughness coefficient and the 2yr 24hr rainfall Length and slope will already be entered from the selected arc 4 Click on the Manning s line in the Variables text window 5 Enter a value of 0 03 in the Variable value edit window 6 Click on the 2 yr 24 hr rainfall line in the Variables text window 7 Enter a value of 1 1 You should notice in the Instructions Results window that you are told what variables need to be defined before a travel time can be computed Once you have entered all the necessary values this same window reports the travel time for this arc In this way you can compute travel time for any arc segment no matter what the application is 8 Select OK Time of Concentration Calculations and Computing a Composite CN 3 11 You have now defined an equation for the overland sheet flow segment in the basin and you are ready to define the next segments as shallow concentrated flow 9 10 11 12 13 14 Double click on the arc labeled B in Figure 3 4 Change the equation type to TR 55 shallow conc eqn Click on the Paved line in
23. entering two points on the curves at essentially the same elevation 6821 99 ft and 6822 ft with the first having no outflow and the second having the discharge over the spillway 640 cfs as defined for this dam 1 7 8 Double click on the reservoir outlet point it is now represented as a triangle since you have defined a reservoir at this location Select the Reservoir Data button Change the Reservoir name to Tcreek Set the Type of storage routing to Reservoir Select the Define button to the right of the reservoir option On the right side of this dialog you will define the Volume or storage capacity data Choose the Known Volume option Toggle on the check boxes for SV Volumes and SE Elevations Select the Define button to the right of the SV option You will define separate XY series for Volumes Elevations and Discharges using the XY Series editor 9 10 11 12 Select New Change the name of the new curve to Volume In the first seven edit fields enter the values 0 200 410 650 1000 1000 1540 acre ft of volume as shown in Figure 4 5 Select the 8 through 20 edit fields and select the DELETE key so that the values are blank rather than zero You can select them all at once the way you do in a spreadsheet since this dialog behaves like a spreadsheet by clicking in the top and while holding the mouse button down dragging to the last or you can select one at a time 4 20 WMS Tu
24. of the basin In order to see the parameters more clearly turn off the display of the DEM Gy Teran Data 15 If needed expand the Terrain Data folder in the Project Explorer Gls DEM 16 From the Project Explorer toggle off the check box for the DEM Your screen should now look like Figure 3 1 Time of Concentration Calculations and Computing a Composite CN 3 3 BS 0 0278 ttt A 14 45 mi 2 Figure 3 1 Drainage basin with parameters computed 3 3 Calculating Percentage of Lake Cover 3 3 1 The regression equation for Region B of Florida includes a parameter LK to define the ratio of the area of lakes in the basin to the total basin area as a percent We will use the Compute Coverage Overlay calculator in WMS to calculate the percentage of lake cover in our drainage basin The only other parameter in the regression equation for Region B of Florida is drainage area DA something that is automatically computed using the Compute Basin Data command Opening the Land Use Coverage In order to compute the percentage of lake cover in our watershed we will read in land use data from a typical USGS land use file Each polygon in the coverage is assigned a land use code that corresponds to a land use type For this land use coverage the codes for water bodies lakes reservoirs wetlands include 52 53 61 and 62 We will look for these codes to determine the value for LK 1 Right click on the Coverages folder in the Project
25. open a project created by WMS run an analysis and view some basic results 1 Right click on Drainage Coverage Tree in the Project Explorer and select Save HMS File 2 Change the HMS project file to CCTrib 3 Start HEC HMS on your computer 4 Select File Open 5 Select the Browse button and browse to the location where you just saved your HMS Project from WMS by default this will be in the hec 1 directory of your tutorial files 6 Select the CCTrib hms project file 7 From the HEC HMS project explorer expand the Basin Models Meteorologic Models and Control Specifications folders 8 Expand the Clear Creek Tributary basin model and then select it The basin model map should appear and your project explorer should look something like the picture below Ose al eae E cctrib4 9 Basin Models DB Clear Creek Tributary E oy CCTrib A Meteorologic Models P WMS Meteorolgic Data A Control Specifications Clear Creek Tributary 9 Select Compute Create Simulation Run 10 Change the Run Name to CCTrib 1 11 Click Next Next Next and Finish to set up the simulation run 12 Select Compute Select Run Select Run gt CCTrib 1 HEC HMS Interface 5 11 13 Select Compute Compute Run CCTrib 1 or the Compute Current a5 Run macro 14 When finished computing select Close 15 Select the CCTrib basin under the Clear Creek Tributary basin model from the HEC HMS project explorer 16 Select Results Glo
26. the Variables text window Enter yes in the Variable value edit window Select OK Repeat for the arc labeled D using the same equation type In this case set the Paved value to no The remaining arc will be defined as an open channel flow arc 15 16 17 18 19 20 21 22 23 24 29 26 27 28 Double click on the arc labeled C in Figure 3 4 Change the arc type to TR 55 Open channel eqn Click on the Manning s n line Enter a value of 0 017 in the Variable value edit window Select the hydraulic radius line in the Variables window Select the Hydraulic Radius button to open up the channel calculator so that the hydraulic radius can be computed from estimates of the curb in the subdivision Change the Channel type to Triangular Enter a longitudinal slope of 0 010 ft ft Enter a Side slope 1 Z1 of 10 Enter a Side slope 2 Z2 of 0 01 Choose the Enter depth option Enter a depth of 0 5 an approximated depth since we do not know what the flow is at this point Select the Calculate button Select OK for both dialogs 3 12 WMS Tutorials Volume 2 You have now defined the necessary parameters for computing travel time using the TR 55 open channel flow Manning s equation If you wish you can continue to experiment with the channel calculator to compute the hydraulic radius rather than entering the given values You now have defined equations and variable values fo
27. the basin Compare the results of the different equations available to best describe the characteristics of the basin 10 Select OK 11 Select the Done button A hydrograph icon will appear next to the basin icon for Basin 1B You can examine the hydrograph in more detail 12 Select the Select Hydrograph tool ir 13 Double click on the hydrograph icon The hydrograph is displayed in the Graphics window 14 Close the hydrograph plot window by clicking on the X in the upper right corner of the window 15 Select File New 16 Select No 3 6 Using TR 55 to Compute Tc and CN Travel times time of concentration lag time and travel time along a routing reach are critical to performing analyses with any of the hydrologic models You will learn of two different ways WMS can be used to compute time of concentration for a TR 55 simulation lag times are computed in the same way e Runoff distances and slopes for each basin are automatically computed whenever you create watershed models from TINs or DEMs and compute basin data These values can then be used in one of several available equations in WMS to compute lag time or time of concentration e If you want to have a little more control and documentation over the lag time or time of concentration you will use a time computation coverage to define critical flow paths Time computation coverages contain flow path arc s for each sub basin An equation to estimate travel time is a
28. 0 0 0 0 0 0 b bafta ba ba bafta ba ba ba bi bs ba ba bi Figure 3 3 Summing the percentages of the codes representing water cover The Coverage Overlay command can be used in a similar fashion to determine the percentage of forested areas codes in the 40 s or any other classification type in a land use file or a soil file 6 3 4 Running NSS Select Done Model NFF The geometric data computed from the DEM has automatically been stored with the NSS data You can now run a simulation using the derived data 1 2 Make sure that the Model combo box is set to NSS Select the Frame macro H Select the Select Basin tool M Double click on the basin icon for Basin 1B Choose Florida from the list of states Highlight Region B from the list of Regional regression equations Select the Select gt button to move Region B to the Selected Equations window Enter 10 8 for the Lake Area variable you may have to scroll the Variable Values window in order to see the Lake Area variable Select the Compute Results button Time of Concentration Calculations and Computing a Composite CN 3 7 The peak flow Q values are displayed in the window at the bottom of the dialog 3 4 1 Exporting the Flow Data Once flow data is computed it may be exported to a text file in the format shown in the window along with pertinent information used in computing the peak flow values 1 Select the Export button 2 Locate a d
29. 2 2 WMS Tutorials Volume 2 2 2 1 Open DEMs 1 2 Close all instances of WMS Open WMS Select File Open Locate the folder C Program Files WMS8I tutorial demedit Open mvcanyon dem and trailmount dem Select OK on the Importing USGS DEMs dialog 2 2 2 Run TOPAZ 1 2 3 Switch to the Drainage module 8 Select DEM Compute TOPAZ Flow Data Select OK Select OK Select Close once TOPAZ finishes running you may have to wait a few seconds to a minute or so Right click on DEM in the Project Explorer and select Display Options 3 Change the Minimum Accumulation For Display to 0 06 mi Select OK Zoom in to the top middle section of the DEM as shown in Figure 2 1 Editing DEMs 2 3 Figure 2 1 Zoom in to the rectangle on the DEM 2 2 3 Basin Delineation 1 2 Switch to the Drainage module Select the Create Outlet Point tool O Click anywhere on the DEM to create an outlet Select OK if you get a message telling you that the outlet is not located in a flow accumulation cell Enter a Feature Point X value of 379589 5 and a Feature Point Y value of 4271008 5 in the Properties window on the right of the screen to edit the outlet location Select DEM Delineate Basins Wizard Select OK Select OK 2 2 4 Basin Delineation Errors The delineation of this basin shown in Figure 2 2 looks suspicious First of all the upper right edge of the basin boundary is linear and flat Th
30. 5 2 2 Open the Soils Data 1 2 Make sure the Soil Type coverage is active in the Project Explorer Right click on GIS Layers in the Project Explorer and select Add Shapefile Data HEC HMS Interface 5 3 3 Open statsgo shp 4 Right click on statsgo shp layer in the Project Explorer 5 Select Open Attribute Table Notice that the table has three fields named AREA PERIMETER and MUID 6 Select OK 5 2 3 Join Soils Database File Table to Shapefile Table 1 Right click on statsgo shp in the Project Explorer 2 Select Join Table to Layer 3 Open statsgoc dbf 4 Ensure that Shapefile Join Field and Table Join Field are both set to MUID 5 Change the Table Data Field to HYDGRP 6 Select OK 7 Right click on statsgo shp in the Project Explorer 8 Select Open Attribute Table Notice that the HYDGRP field is now a part of the shapefile 9 Select OK 5 2 4 Convert Soil Shapefile Data to Feature Objects 1 Choose the Select Shapes tool k 2 Draw a selection box around the DEM extents 3 Select Mapping Shapes gt Feature Objects 4 Select Next This window shows all of the attribute fields in the soils shape file Because this file was derived from a standard NRCS statsgo file you will notice that the hydrologic soil groups field is named HYDGRP and so WMS will automatically map this to be the soil type If the attribute field were named 5 4 WMS Tutorials Volume 2 anything other than HYDGRP then you would hav
31. 8 29 30 31 32 33 34 Rational Method Interface 6 11 Select the Compute IDF Curves button in the Outlet column Select the line of text for the 10 yr recurrence interval Select the Compute Intensity button Select Done Select the Compute Hydrographs button in the Outlet column Choose Traditional method Choose the Rational Method hydrograph option Select Done Select OK in the Rational Method dialog Double click on the hydrograph icon for the most downstream outlet Close the hydrograph plot window when you are done viewing by selecting the X in the upper right corner of the window 6 2 5 Combining Runoff from Multiple Basins Besides the traditional method of computing peak flows and hydrographs for multiple sub basins within a watershed WMS will also allow you to lag hydrographs computed for basins and add at outlets in order to produce downstream peak flows and hydrographs 1 6 7 Double click on the downstream most outlet point outlet of the Lower basin Select the Compute Hydrographs button in the Outlet column Choose the Route by summing method Choose the Rational method hydrograph option Select Done Select OK Double click the hydrograph icon for the bottom most outlet You can now see the difference between these two methods as both hydrographs are plotted in the window 6 10 WMS Tutorials Volume 2 8 Close the hydrograph plot window when you are done viewing by select
32. Name the file wiztopo jpg and click Save 9 Make sure the options for NED data SRTM data and TerraServer urban are toggled off then click Download Data from Web WMS will proceed to download the selected files for the project area you specified 10 Click OK to use the recommended map scale 11 Select Yes if asked to generate pyramids 12 Repeat steps 10 and 11 for the second image Once the image files have been downloaded from Web Services WMS automatically opens the files into your WMS project 13 Click Next gt to advance to the next step Computing Flow Directions and Accumulations WMS computes flow directions and flow accumulations to create streams on the DEM using a program called TOPAZ 1 Make sure the option to Write TOPAZ files to a temp directory is selected and that the selected sub basin areas are in Square Miles and that distances are computed in Feet 2 Select Compute TOPAZ 3 Click Close when TOPAZ terminates 4 Click Next gt to advance to the next step DEM Delineation 1 7 1 3 5 Define Outlets and Delineate Basins The Hydrologic Modeling Wizard window is a non modal window meaning it lets you interact with the main model window with the window still open 1 Zoom in around the area shown in Figure 1 4 2 Choose the Create Outlet Point tool from the wizard window Oo D AVA Figure 1 4 DEM Zoom Area 3 Place the outlet just upstream of the branch junction shown in Figure 1 5
33. OK Since we will not be using them until later hide the Land Use and Soil Type coverages by toggling off their check boxes in the Project Explorer Select the Drainage coverage from the Project Explorer to make sure it is the active coverage 4 2 7 Delineate the Watershed 1 2 Select the Drainage module 8 Select the Frame macro 4 Select DEM Compute TOPAZ Flow Data Select OK Select OK in the Units dialog Select Close once TOPAZ finishes running you may have to wait a few seconds to a minute or so Select the Zoom tool X Zoom in by dragging a box as illustrated in Figure 4 1 4 6 WMS Tutorials Volume 2 RER Se a ky OSS x ER an ENEE A i Figure 4 1 Zoom in on the area bounded by the rectangle above 9 Select the Create Outlet Point tool O 10 Create a new outlet point where the tributary you just zoomed in on separates from the main stream as illustrated by the arrow in Figure 4 1 Make certain that the outlet point is on the tributary and not part of the main stream Also the outlet needs to be inside one of the flow accumulation blue cells WMS will move the outlet to the nearest flow accumulation cell if you do not click right in one of the flow accumulations cells 11 Select the Frame macro 4 12 Select DEM Delineate Basins Wizard 13 Select OK 14 Select OK You have now completed the delineation of a single watershed In order to make the vi
34. PEE E AE TE EE AE A T E A A T ES 2 1 Ded DEM FIPS COMMAND soseices ccoeadvfesediced evivnsedeccesiccstssentusedesadovedbenaededeuscesageencadeestndertatendededsveectisotetesedstnses 2 1 23 ADDING STREAM ARCS TO EDIT FLOW DIRECTIONS AND BASINS ssssssssececeesssseceeececeesssseceeeeeceenens 2 6 2 4 EDITING FLOW DIRECTIONS cccssveescestedvessseestccedsedeweesuuaiaedeveveesepeandaees vever enter decdessecnteanca desevertensceevedaes 2 13 2 5 ELONE BB OIN EEE iat ETE EEE aA testa a acs ea atta eee ok 2 16 3 TIME OF CONCENTRATION CALCULATIONS AND COMPUTING A COMPOSITE CN 3 1 3 1 OPENING THE DRAINAGE BASIN ccccceessssscecececeeeescaecececseseseaececececsensaaececececsesaaeceeecsceesaaeceeeeeeeeneas 3 1 3 2 PREPARE THE BASIN FOR USE WITH NSS cccccecessessececececsesseaececececsesnsaececcceceessaaeeeeececeessaseeeeceeseneas 3 2 3 3 CALCULATING PERCENTAGE OF LAKE COVER sssssssssccececsessscececececsesseaececececsenssaeceeeceesesnaaeeeeeeeeeenees 3 3 3 4 RUNNING NSS eheticiie A advent E AASE E E olen E E E ook E E 3 6 3 5 TIME COMPUTATION LAG TIME CALCULATION cc cccccccecsessceceeececsesseaeceeececsesseaeceeeeeceesnsaeeeeeceesenees 3 7 3 6 USING TR 55 TO COMPUTE TC AND CN cccccccccecssssssececececsenssaeceeececsessaaececececeesssaeeeeececeessaasceseeeceeneas 3 8 3 7 READING A PR 55 PROJECT ds casessecenccoxdstesuzecnancotosisaatucndenboee ssns E bvmbees oii coves tude GS 3 9 3 8 ASSIGNING EQUATIONS TO TIME COMPUTATION ARC
35. S cssessssceececeessaececececeessaeceeececeessasceeeceeeeneas 3 9 3 9 COMPUTING TIME OF CONCENTRATION FOR A TR 55 SIMULATION ccsscccccceceesssssceeceeceesssssaeeeeeees 3 12 3 10 COMPUTING A COMPOSITE CURVE NUMBER ccsssessssesececeesessscecececeesescaeceeccecsesaaeeeeececeessasseeeeeees 3 13 Sel MORE TRE55 S E E ETEO EE E OEE N EEA E E EE OTEO 3 15 S12 GCONCEUSION AEE APAA SE E EE E A O vase och bade AE E E EEA E EY 3 15 4 HEC LINTERFEACE iisscssscsciescscadschevasstasssccascosscnctesesdecoostbeaedeseicsduactucoccenescesecsabeessesndcgasassseeseaseseedsesasonstees 4 1 4 1 OBJECTIVES eiea e a a a e a A 4 1 4 2 DELINEATING THE WATERSHED ss 2 03 rr Etra Ear E n EIE NEEE Eare E EE ETIN ERIT ieren 4 2 4 3 SINGLE BASIN aI D KPEE EEEE SEEE E E E E E A E 4 7 4 4 COMPUTING THE CN USING LAND USE AND SOILS DATA ccccccccccecsessssscecececeessaecesececeensnssaeeeeeees 4 11 4 5 ADDING SUB BASINS AND ROUTING ccsessssesececeesessscececececsenseaeceecceccessaaececececeensaaeeeeececseneansaeeeeeens 4 12 4 6 MODELING A RESERVOIR IN HEC 1 ou ce cececceccccccecsesessscecececeesesececeeeceeseaaeceeccecsesssaeeeeececsessaasaeeeeeees 4 18 47 REVIEWING OU TPUTes2 4sse cece toss E eS P EE ae OEE 4 22 4 8 ERINLE EORI OIN eee EE Ne 4 22 5 HEC HMS INTERFACE icsscesssssisssicsssri oiiro sises sudoers sosaties ossi SS E SEE oE ES Een Essa 5 1 5 1 OBJECTIVES OME ET AREA E ENE OE EAEE S EEN TEE E EET E E EEE TEO T EIE 5 1 D2 DELINEATING
36. Toggle the SCS Curve Number from the Show column in the Display options window 8 Enter an SCS Curve Number of 70 We will compute a CN value from actual land use and soil files later For the SCS CN method initials losses are estimated as 20 of the maximum storage value computed from the CN when the initial loss is zero If you wish to override this computation then you would enter a value other than zero For now we will assume there is no impervious area 9 Toggle on the Display of the Transform option you may have to scroll vertically in the Display options window 10 Show the SCS parameters by toggling this option on in the Display options window 11 Scroll horizontally in the Properties window and choose the Compute button under Basin Data the SCS transform method is the default 12 Set the Computation Type to Compute Lag Time the default 13 Set the Method drop down list to SCS Method near the bottom of the list 14 Select OK to update the computed lag time for the SCS dimensionless method scroll horizontally to view if you would like 15 Select OK You now have all of the parameters set to run a single basin analysis 5 3 4 Running HEC HMS Whenever you run an HEC HMS simulation you must save the information created in WMS to HEC HMS files and then load it as a project in HEC HMS 5 10 WMS Tutorials Volume 2 This tutorial is not a comprehensive review of HEC HMS but should give you an idea of how to
37. Volume 1 chapter 2 Open the image and be sure that both DEM and image are in the same coordinate system 7 2 Basin Delineation You will want to identify a watershed that is defined completely within your DEM If your area does not contain a complete watershed or the watershed you were trying to work on then you may need to repeat the delineation 1 2 7 3 Running NSS Switch to the Drainage module amp Run TOPAZ and delineate your watershed Now you should be prepared to run a basin NSS simulation 1 2 Switch to the Hydrologic Modeling module ae Make sure Model combo box is set to NSS Choose the Select Basin tool M Double click on your basin Select your state and region Define any variables not computed You may wish to get land use soils or rainfall data and use it to automatically calculate other variables where needed Compute the peak flows National Streamflow Statistics Program NSS Interface 7 3 At this point you have your results and should feel confident that you could repeat this process again and again You may wish to adjust display settings and add annotations in preparation of report documentation on a project When you are finished do the following before moving on to the rest of the exercise 8 Save the project if you wish 9 Select File New 10 Select No if asked if you want to save your changes 7 4 Utilizing an NSS Region Coverage This portion of the exercise is
38. WMS 1 Select the Get Data tool Pa 2 Drag a box around the extents of the rectangle as shown in Figure 2 6 to define the region of the topographic image 2 8 WMS Tutorials Volume 2 fall Bs X UEA Figure 2 6 Define the region of the topographic image 3 Toggle on the TerraServer topo option 4 Select OK to start the downloading process 5 Enter TrailMtTopo and click Save 6 Click Yes to create the default wizard file name 7 Set the map scale to 2m It may take a few minutes to complete the downloading process WMS will automatically open the image after downloading it If you were able to successfully complete all the steps in this section you can skip section 2 3 3 2 3 3 Open TIF File 1 Select File Open a 2 Open trailmountain tif 2 3 4 Run TOPAZ 1 Switch to the Drainage module amp Editing DEMs 2 9 Select DEM Compute TOPAZ Flow Data Select OK Select OK Select Close once TOPAZ finishes running you may have to wait a few seconds to a minute or so Right click on DEM and select Display Options Y Change the Minimum Accumulation For Display to 0 06 mi Select OK Zoom in around the topographic image that you just downloaded from the TerraServer or zoom in to the rectangle shown in Figure 2 6 2 3 5 Basin Delineation 1 While in the Drainage module select the Create Outlet Point tool O Click anywhere on the DEM to create an outlet Select OK if you get
39. Watershed Modeling System WMS v8 1 TUTORIALS Volume 2 WATERSHED MODELING WMS 8 1 Tutorials Volume 2 Copyright 2008 Aquaveo LLC All Rights Reserved Unauthorized duplication of the WMS software or documentation is strictly prohibited AQUAVEO LLC MAKES NO WARRANTIES EITHER EXPRESS OR IMPLIED REGARDING THE PROGRAM WMS AND ITS FITNESS FOR ANY PARTICULAR PURPOSE OR THE VALIDITY OF THE INFORMATION CONTAINED IN THIS USER S MANUAL The software WMS is a product of the Aquaveo LLC For more information about this software and related products contact Aquaveo at Aquaveo 75 South 200 East Suite 201 Provo Utah 84606 Tel 801 691 5528 e mail wms aquaveo com WWW http www aquaveo com For technical support contact Aquaveo s tech support number at 801 691 5530 Monday Friday 8am 5pm Mountain Time TABLE OF CONTENTS 1 DEM DELINEATION jsiccscssssssecesaccdsscsseoccvasscosntedsossseonscousssssestencdececssovsevedessoadaessns soscsssacesesedsesadessaceseaseeses 1 1 1 1 OBJECTIVES a A a E AA SBE A ERE A 1 1 1 2 IMPORTING DEM DATA RE E e EE E EE EE E EE 1 1 1 3 WATERSHED DELINEATION USING THE HYDROLOGIC MODELING WIZARD ss sccccececessesseceeeeeeeeees 1 3 1 4 IBIR Y EVS Ane B DY KTE E ESA E E E E AE E OE EE 1 11 1 5 MORE BASIN DELINEATION e n a A NEE OE A A EEE EI O TRES 1 13 1 6 CONCLUSIONS EE E E E NEEE ENP 1 13 2 EDITING DEMS ennnen se e ai aas s e Ere e Tiasa 2 1 2 1 OBJECTIVES EE AEE AEE RE E E
40. Y On the Map tab toggle on Vertices Select OK Select the Select Feature Vertex tool Ae Select the vertex that is just below the main branching point you just zoomed in around Select DEM Node lt gt Outlet You created the outlet point just below the branch in order to have a single upstream basin If you wanted a separate basin for each upstream branch you could define the branching node to be an outlet Thus WMS would automatically assume that you want separate basins for each branch so we 4 14 WMS Tutorials Volume 2 have created a node just downstream of the branch and defined it as the outlet for the upper basin 10 Select the Frame macro H3 11 Select the Zoom tool a 12 Create a zoom box around the region identified by a box in Figure 4 4 Figure 4 4 Zoom in on the area indicated by the rectangle 13 Select the Select Feature Vertex tool A 14 Select the vertex that is just below the feature node where the streams branch 15 Select DEM Node lt gt Outlet 16 Select the Frame macro H 17 Select DEM Delineate Basins Wizard 18 Select OK to delete and recreate feature data 19 Select OK 20 HEC 1 Interface 4 15 Select OK 4 5 2 Updating the Basin Parameters You will have to recompute the CN values and define precipitation and lag time for the basins 11 12 13 14 15 16 17 18 Select the Hydrologic Modeling module ap Select Calculators Compute GIS A
41. a message telling you that the outlet is not located in a flow accumulation cell Enter a Feature Point X value of 375604 9 and a Feature Point Y value of 4271336 7 in the Properties window on the right of the screen to edit the outlet location Select DEM Delineate Basins Wizard Select OK twice 2 3 6 Add Stream Arcs Along Road 1 2 Choose the Zoom tool X Zoom in along the road to the rectangle shown in Figure 2 7 2 10 WMS Tutorials Volume 2 Figure 2 7 Zoom in to rectangle along road 3 4 Select the Drainage coverage in the Project Explorer Choose the Create Feature Arc tool amp Select Feature Objects Attributes Select the Stream option Select OK Create two stream arcs along the road as shown in Figure 2 8 Begin each arc by clicking on the node on the existing stream arc which is just upstream of the outlet and end by double clicking Only one basin is delineated by adding the stream arcs beginning at this node It is possible to create the stream arcs beginning at the actual outlet point but this causes multiple basins to be delineated which may not be desirable Also to avoid creating basins on the south side of the highway draw each arc on the north side of the flow accumulation lines You are creating the stream arcs along the road to show that the water collected by the road drains into the same area the main watershed drains into Editing DEMs 2 11 Figure 2 8 Roadway collectio
42. and Computing a Composite CN 3 13 The sum of the travel times for these arcs will be used as the time of concentration for this basin Note that you could bring up the time computation attributes dialog and change the equation or any of the equation variables by selecting the Edit Arcs button 3 10 Computing a Composite Curve Number In this part of the exercise you will learn how to overlay land use and soil coverages on your delineated watershed in order to derive a curve number CN 3 10 1 Land Use Table Now you need to create a land use table with IDs and CNs for each type of land use on your map A table has been provided but it is incomplete To finish the table with all of the IDs and CNs for the shapefiles in the project or just to edit the table in general complete the following steps 1 Select File Edit File 2 Open landuse tbl 3 If prompted choose a text editor to edit the file with by choosing Notepad or another favorite editor in the Open With drop down list and select OK In the text editor you will find three lines of text listing three IDs along with their CN values The file format for this file is an ID value followed by a comma the name of the land use ID in quotation marks followed by a comma followed by the comma separated CN values for soil types A B C and D respectively This file includes CN values for landuse types Transportation Communications Other Urban or Built Up Land and
43. asin HEC HMS analysis that includes routing the upper basins through the reaches connecting them to the watershed outlet 5 22 WMS Tutorials Volume 2 10 11 12 13 14 15 16 17 18 19 Right click on Drainage Coverage Tree in the Project Explorer and select Save HMS File Name the HMS project file CCTribReservoir and Save Start HEC HMS on your computer Select File Open Select the Browse button and browse to the location where you just saved your HMS Project from WMS by default this will be in the hec 1 directory of your tutorial files Select the CCTribReservoir hms project file From the HEC HMS project explorer expand the Basin Models Meteorologic Models and Control Specifications folders Expand the Clear Creek Tributary basin model and then select it Change the Run Name to CCTribReservoir 1 Click Next Next Next and Finish to set up the simulation run Select Compute Create Simulation Run Select Compute Select Run Select Run CCTribReservoir 1 Select Compute Compute Run CCTribReservoir 1 or the Compute IS Current Run macro When finished computing select Close Select different elements basins junctions reaches reservoirs and view results Select Results Global Summary Table and explore Select Results Element Graph and explore Select Results Element Summary Table and explore Select Results Element Time Series Table and explore You may continue to explor
44. ate in the third line 5 Leave the Day Month and Year fields alone HEC 1 allows you to enter a date but almost always you are simulating some kind of hypothetical or design storm and not an actual storm If you change the simulation date you will need to be careful to make sure the storm date is in synch but if you leave it alone there will not be a problem 6 Enter 5 minutes for the Computation time interval and 300 for the Number of hydrograph ordinates Leave the Beginning time at 0 An HEC 1 simulation will run for a length of time equal to the time step multiplied by the number of ordinates If you are simulating a 24 hr storm but only run the simulation for 12 hours you will not capture the full hydrograph Conversely if you run a 24 hr simulation for 96 hrs you are probably going to have a lot of runoff ordinates equal to 0 at the end In this case we are running 4 8 WMS Tutorials Volume 2 4 3 2 the simulation for 1500 minutes slightly more than 24 hours with an ordinate on the hydrograph being computed for every 5 minutes 7 Set the computation units to English units this should be the default Setting the computation units DOES NOT cause any units conversion to take place You are simply telling HEC 1 that you will provide input units in English units sq miles for area inches for rain feet miles for length and expect results of computation to be in English units cfs If you specify Metric then you mus
45. bal Summary Table and explore 17 Select Results Element Graph and explore 18 Select Results Element Summary Table and explore 19 Select Results Element Time Series Table and explore You now have a completed HEC HMS simulation for a single basin and the resulting hydrograph for the CCTrib subbasin element should look something like the one shown in Figure 5 2 Graph for Subbasin CCTrib Subbasin Element CCTrib Results for Run CCTrib 1 Precip IN wa re Oo 2S 2 ira 500 0 12 00 18 00 00 00 06 00 12 00 17May2006 18May2006 Legend E Run CCTRIB 1 Bement CCTRIB Result Incremental Precipitation E Run CCTRIB 1 Bement CCTRIB Result Precipitation Loss Run CCTRIB 1 Bement CCTRIB Result Outflow Run CCTRIB 1 Bement CCTRIB Result Baseflow Figure 5 2 Solution hydrograph for HEC HMS simulation 20 You may continue to explore the HEC HMS input parameters passed from WMS and computed results or any other options 5 12 WMS Tutorials Volume 2 21 When finished close the Global and Element summary tables and graph windows and exit HEC HMS by selecting File Exit 22 Select Yes when prompted to save the project 5 4 Computing the CN Using Land Use and Soils Data 5 4 1 In the initial simulation you estimated a CN but with access to the Internet it is simple to compute a composite CN based on digital land use and soils files This was demonstrated in more detail in the Advanced Feature Objects exer
46. ce that are automatically computed by WMS when delineating a watershed You were already introduced to this program in a previous chapter discussing overlay and time of travel computations Volume 2 Chapter 3 In this exercise you will have the chance to review data collection and starting a project from scratch You will then run the NSS program for your selected area to compute the peak flows for the different return periods If your equation ends up needing variables not derived from the DEM alone then you might consider doing the general overlay in order to compute percentages of land use soil or rainfall for different regions 7 1 Data Collection You will begin by downloading the necessary files Remember that you can go to the geospatial data acquisition GSDA web page on the xmswiki at http xmswiki com wiki GSDA GSDA as a starting point 7 2 WMS Tutorials Volume 2 Download a DEM from the National Elevation Dataset web site or another similar site This should be an area that contains a watershed of personal interest to you Open the DEM in a new instance of WMS and convert the coordinates as necessary See the chapter on DEM basics if you need help Volume 1 chapter 4 Download the topographic map from the TerraServer by using the web services option in WMS if available or by going to the TerraServer web site directly and downloading the image and accompanying world file See the chapter on images if you need help
47. cise Volume 1 chapter 6 but you will go through the steps here as a review Computing a Composite CN At the beginning of this tutorial you loaded digital land use and soils files for the purpose of calculating a CN In addition to this data you must have a table defined that relates CN values for each of the four different hydrologic soil groups A B C D for each land use This is described in detail at the gsda website http www xmswiki com wiki GSDA GSDA and in the Advanced Feature Objects exercise Volume 1 chapter 6 For this exercise you will read in an existing file you can examine it in a text editor if you wish and compute the CN numbers 1 While it is not necessary to have the Land Use and Soil Type coverages displayed for the computations to work you may wish to make them visible again by toggling on their check boxes in the Project Explorer 2 Select the Drainage coverage to make sure it is the active coverage 3 Select the Hydrologic Modeling module ae 4 Select Calculators Compute GIS Attributes 5 Select the Jmport button to load the mapping table 6 Select OK to overwrite the current definition 7 Find and open the file named scsland tbl 8 Select OK to compute the CN from the land use and soils layers You should see the computed CN displayed in the Runoff Curve Number Report and above the area label in the WMS graphics window 9 Close the Runoff Curve Number Report HEC HMS Interface 5 13 5
48. d 13 Select OK 14 Select OK You have now completed the delineation of a single watershed In order to make the view clearer for defining the hydrologic model you can turn off many of the DEM and other display options 15 Right click on DEM in the Project Explorer and select Display Options p 16 On the DEM tab toggle off the display for Watershed Stream Flow Accumulation and DEM Contours HEC HMS Interface 5 7 17 On the Map tab toggle Vertices off 18 Select OK 5 3 Single Basin Analysis 5 3 1 The first simulation will be defined for a single basin You will need to enter the global or Job Control parameters as well as basin and meteorological data Setting up the Job Control Most of the parameters required for a HEC HMS model are defined for basins outlets and reaches However there are some global parameters that control the overall simulation and are not specific to any basin or reach in the model These parameters are defined in the WMS interface using the Job Control dialog 1 Switch to the Hydrologic Modeling module 2 HEC 1 should be the default model so change the default model to HEC HMS by selecting it from the drop down list of models found in the Edit Window 3 Select HEC HMS Job Control 4 Enter Clear Creek Tributary in the Name field 5 Inthe Description field you can enter Your name By default the simulation is set to run for 24 hours starting from today s date at 15 minu
49. d computed results or any other options 20 When finished close the Global and Element summary tables and graph windows and exit HEC HMS by selecting File Exit 21 Select Yes when prompted to save the project 5 5 Adding Sub basins and Routing You will now subdivide the watershed into two upper basins and one lower basin and define routing for the reaches that connect the upper basins to the watershed outlet 5 5 1 Delineating the Sub basin 1 Select the Zoom tool X 2 Create a zoom box around the region identified by a box in Figure 4 3 A 31 90 mi Sayre 6 Figure 5 3 Zoom in on the area indicated by the rectangle 3 Right click on the Drainage coverage in the Project Explorer and select Display Options Y 9 HEC HMS Interface 5 15 On the Map tab toggle on Vertices Select OK Select the Drainage module Select the Select Feature Vertex tool A Select the vertex that is just below the main branching point you just zoomed in around Select DEM Node lt gt Outlet You created the outlet point just below the branch in order to have a single upstream basin If you wanted a separate basin for each upstream branch you could define the branching node to be an outlet Thus WMS would automatically assume that you want separate basins for each branch so we have created a node just downstream of the branch and defined it as the outlet for the upper basin 10 Select the Frame macro ad 11 Select the Zoo
50. e of Concentration to Small HH Middle oso B O When you are finished entering the parameters choose OK on the Rational Method dialog 6 4 WMS Tutorials Volume 2 6 2 2 A runoff coefficient coverage could be used to automatically map C values and basin data or a time computation coverage could be employed to determine Tc values but they can also be computed estimated separately and entered as demonstrated here Defining the Rainfall Intensity i As part of the WMS interface to the Rational Method you can compute IDF curves using either HYDRO 35 NOAA or user defined data For this exercise we will use HYDRO 35 data and a recurrence interval of 10 years 1 2 5 Double click the icon for the Upper catchment Select the Compute IDF Curves button from the Basin section of the Rational Method dialog Make sure the HYDRO 35 Data Eastern US radio group button is selected and select the Define Storm Data button Enter the following values to define IDF curves using HYDRO 35 Depth in 2 yr 15 min Select the OK button after correctly entering the rainfall values The IDF curves for the 2 5 10 25 50 and 100 year recurrence intervals will be drawn and values listed for selected times given in the windows on the right of the IDF Computation dialog 6 From the text window in the upper right hand part of the dialog click on the line of data for the 10 yr recurrence interval as shown
51. e the HEC HMS input parameters passed from WMS and computed results or any other options 20 When finished close the Global and Element summary tables and graph windows and exit HEC HMS by selecting File Exit HEC HMS Interface 5 23 21 Select Yes when prompted to save the project 5 7 Conclusion This concludes the exercise defining HEC HMS files and displaying hydrographs The concepts learned include the following Entering job control parameters Defining basin parameters such as loss rates precipitation and hydrograph methodology a watershed analysis Defining routing parameters Routing a hydrograph through a reservoir Saving and running HEC HMS simulations CHAPTER 6 Rational Method Interface The Rational Method is one of the simplest and best known methods routinely applied in urban hydrology Peak flows are computed from the simple equation Q kCiA where Q Peak flow k Conversion factor C Runoff coefficient i Rainfall intensity A Area In this exercise you will learn how to solve problems using a digital terrain model and the Rational Method 6 1 Reading in Terrain Data The terrain model used in this exercise is a TIN for a small portion of a city The elevation data was obtained by digitizing a contour map 1 Close all instances of WMS 2 Open WMS 6 2 WMS Tutorials Volume 2 3 4 a Select File Open Locate the folder C Program Files WMS8I tutorial rational Fi
52. e to manually map it using the drop down list in the spreadsheet J 6 7 8 Make sure the HYDGRP field is mapped to the SCS soil type attribute Select Next Select Finish Clear the selected polygons by single clicking somewhere beyond the extents of the shapefile polygons Hide the statsgo shp file by toggling off its check box in the Project Explorer 5 2 5 Open the Land Use Data 1 10 11 Select the Land Use coverage in the Project Explorer to designate it as the active coverage Right click on GIS Layers in the Project Explorer and select Add Shapefile Data Open _richut shp Choose the Select Shapes tool k Draw a selection box around the DEM extents Select Mapping Shapes gt Feature Objects Select Next Make sure the LUCODE field is mapped to the Land use attribute Select Next Select Finish Hide the _richut shp file by toggling off its check box in the Project Explorer 5 2 6 Convert Set the Coordinate System of the Data 1 2 Select Edit Coordinate Conversion Select the Specify option in the Current Projection section of the Reproject Current dialog 10 11 12 13 14 HEC HMS Interface 5 5 Select Set Projection Set Projection to Geographic and Datum to NAD 83 Select OK Set Vertical Units to Meters In the New Projection section select Global Projection Select Set Projection Set Projection to UTM Datum to NAD 83 Planar Units to METERS and Zone to
53. eate using the new basin delineation 2 6 WMS Tutorials Volume 2 3 Select OK 4 Select OK Figure 2 5 shows the correct basin delineation Figure 2 5 Final basin delineation 2 3 Adding Stream Arcs to Edit Flow Directions and Basins Sometimes you will need to add stream arcs to your basin to represent water that accumulates along man made objects such as roads Roads often disrupt the natural flow of watersheds and water collects along roads just as it collects in a stream This collected water needs to be added into your watershed in order to properly model the real life situation 2 3 1 Open Data Files 1 Select File New 2 Select No when asked to save changes 3 Select File Open a 4 Locate the folder C Program Files WMS8I tutorial demedit 5 Open trailmount dem 6 Select OK on Importing USGS DEMs Dialog Editing DEMs 2 7 7 Select Edit Current Coordinates to set your current coordinates 8 Select Global Projection 9 Select Set Projection 10 Set the Projection to UTM Datum to NAD 27 Planar Units to METERS and Zone to 12 114 W 108 W Northern Hemisphere 11 Select OK 12 Set Vertical Units to Meters 13 Select OK Skip section 2 3 2 if you are not able to connect to the Internet using your computer 2 3 2 Getting a Background Image Using the TerraServer Using an Internet connection we will now download the topographic map image directly from the TerraServer and open it in
54. ed and polygons that were digitized from the image 1 Switch to the Map module R 2 Select File Open 3 Locate the folder C Program Files WMS8I tutorial nss 4 Open NSSmap_FL jpg 7 4 WMS Tutorials Volume 2 7 4 1 Assigning Regions to Feature Polygons We see from the image that Florida has three regions A B and C You will now open a WMS MAP file that contains these three polygons in an NSS Region coverage In the interest of time the polygons have already been digitized see the chapter on feature objects in Volume 1 for more information about digitizing building polygons but the assignment of attributes state region has been left for you to do 1 Select File Open a 2 Open NSSmap_FL map This file was digitized directly from the image See Volume 1 Chapter 3 Basic Feature Objects for information on how to digitize features from images 3 Choose the Select Feature Polygon tool DI 4 Double click in the polygon corresponding to the region labeled C as shown in Figure 7 1 Double click here UNDFFINFD VE k3 i w Figure 7 1 Image displaying NSS Regions for Florida 5 Choose Florida from the State list 6 Choose Region C from the NSS Region list National Streamflow Statistics Program NSS Interface 7 5 7 Select OK 8 Assign NSS Regions for the remaining two polygons in the same Manner 7 4 2 Opening the Watershed 1 Select File Open a 2 Open NSS_FL wpr
55. erive many of the parameters Land use and soil shapefiles downloaded from the Internet will be used to develop a SCS curve number CN value After establishing the initial HMS model other variations will be developed including defining multiple basins with reach routing and including a reservoir with storage routing 5 2 WMS Tutorials Volume 2 5 2 Delineating the Watershed Since the land use soil type and DEM data for our watershed all originate in the Geographic coordinate system we will begin by opening them together and converting them to UTM coordinates The land use and soil type data were downloaded from the Environmental Protection Agency EPA website The DEM data used for this watershed were previously downloaded from the National Elevation Dataset website as was demonstrated in the DEM Basics exercise Volume 1 chapter 4 1 2 Close all instances of WMS Open WMS a Select File Open 7 Locate the folder C Program Files WMS8I tutorial hec 1 Select NED GRIDFLOAT Header hdr from the Files of type list of file filters Open 67845267 hdr Select OK When prompted if you want to convert the current coordinates select No 5 2 1 Create Land Use and Soil Coverages 1 2 3 4 3 Right click on the Coverages folder in the Project Explorer Select New Coverage Change the coverage type to Land Use Select OK Create a new coverage once again and set its coverage type to Soil Type
56. eveloped including defining multiple basins with reach routing and including a reservoir with storage routing 4 2 WMS Tutorials Volume 2 4 2 Delineating the Watershed Since the land use soil type and DEM data for our watershed all originate in the Geographic coordinate system we will begin by opening them together and converting them to UTM coordinates The land use and soil type data were downloaded from the Environmental Protection Agency EPA website The DEM data used for this watershed were previously downloaded from the National Elevation Dataset website as was demonstrated in the DEM Basics exercise Volume 1 chapter 4 1 2 Close all instances of WMS Open WMS a Select File Open 7 Locate the folder C Program Files WMS8I tutorial hec 1 Select NED GRIDFLOAT Header hdr from the Files of type list of file filters Open 67845267 hdr Select OK When prompted if you want to convert the current coordinates select No 4 2 1 Create Land Use and Soil Coverages 1 2 3 4 3 Right click on the Coverages folder in the Project Explorer Select New Coverage Change the coverage type to Land Use Select OK Create a new coverage once again and set its coverage type to Soil Type 4 2 2 Open the Soils Data 1 2 Make sure the Soil Type coverage is active in the Project Explorer Right click on GIS layers in the Project Explorer and select Add Shapefile Data HEC 1 Interface 4 3
57. ew clearer for defining the hydrologic model you can turn off many of the DEM and other display options 15 Right click on DEM in the Project Explorer and select Display Options Y 16 On the DEM tab toggle off the display for Watershed Stream Flow Accumulation and DEM Contours HEC 1 Interface 4 7 17 On the Map tab toggle Vertices off 18 Select OK 4 3 Single Basin Analysis 4 3 1 The first simulation will be defined for a single basin You will need to enter the global or Job Control parameters as well as the rainfall event loss method and unit hydrograph method Setting up the Job Control Most of the parameters required for a HEC 1 model are defined for basins outlets and reaches However there are many global parameters that control the overall simulation and are not specific to any basin or reach in the model These parameters are defined in the WMS interface using the Job Control dialog 1 Switch to the Hydrologic Modeling module amp 2 HEC 1 should be the default model but if it is not select it from the drop down list of models found in the Edit Window 3 Select HEC 1 Job Control 4 The first three lines are for comments identification at the top of the HEC 1 input file The first line already has information indicating that the input file is generated by WMS you can change this if you want Enter Clear Creek Tributary Watershed for the second ID line Enter your name and current d
58. g Entering job control parameters Defining basin parameters such as loss rates precipitation and hydrograph methodology a watershed analysis Defining routing parameters Routing a hydrograph through a reservoir HEC 1 Interface 4 23 e Saving HEC 1 input files e Reading hydrograph results CHAPTER 5 HEC HMS Interface WMS has a graphical interface to HEC HMS as well and this tutorial is similar to the previous except that it focuses on the use of the HMS interface Geometric attributes such as areas lengths and slopes are computed automatically from the digital watershed Parameters such as loss rates base flow unit hydrograph method and routing data are entered through a series of interactive dialog boxes Once the parameters needed to define an HMS model have been entered an input file with the proper format for HMS can be written automatically Since only parts of the HMS input file are defined in this chapter you are encouraged to explore the different available options of each dialog being sure to select the given method and values before exiting the dialog Unlike HEC 1 you will need to export the HMS files from WMS and then run the HMS graphical user interface to view the results In order to do this you should have the most recent version of HMS installed 5 1 Objectives As a review you will delineate a watershed from a DEM You will then develop a simple single basin model using the delineated watershed to d
59. hat we can route the hydrograph through the reservoir before routing it downstream 1 Select the Select Outlet tool Select the outlet of the upper left basin 3 Right click on the outlet and select Add Reservoir Setting up the Reservoir Routing Parameters In order to define reservoir routing with HEC HMS you must define elevation vs storage storage capacity curve and elevation vs discharge rating curves You can enter values directly or enter hydraulic structures and compute the values but in this exercise you will enter the values directly You will use the same elevation values for both curves For this example we want to have no outflow until the elevation in the reservoir reaches the spillway Since HEC HMS linearly interpolates between consecutive points on the elevation discharge and elevation volume curves we will trick it by entering two points on the curves at essentially the same elevation 6821 99 ft and 6822 ft with the first having no outflow and the second having the discharge over the spillway 640 cfs as defined for this dam 1 Double click on the reservoir outlet point it is now represented as a triangle since you have defined a reservoir at this location 2 Change the Reservoir name to Tcreek 3 Set the Method drop down to be Elevation Storage Discharge What you need to input to define reservoir routing is the initial conditions of the reservoir The initial condition can be defined as an elevat
60. he outlet of the upper left basin It has a storage capacity of 1000 ac ft at the spillway level and 1540 ac ft at the dam crest Defining a Reservoir in Combination with Routing One of the routing methods available in HEC 1 is Storage routing which can be used to define reservoir routing However in this case we are already using Muskingum Cunge routing to move the hydrograph through the reach connecting the upper left basin to the watershed outlet so we must define the outlet as a reservoir so that we can route the hydrograph through the reservoir before routing it downstream 1 Select the Select Outlet tool amp Select the outlet of the upper left basin Right click on the outlet you have just selected and select Add Reservoir Setting up the Reservoir Routing Parameters In order to define reservoir routing with HEC 1 you must define elevation vs storage storage capacity curve and elevation vs discharge rating curves You can enter values directly or enter hydraulic structures and compute the values but in this exercise you will enter the values directly You will use the same HEC 1 Interface 4 19 elevation values for both curves this is common but not a requirement in HEC 1 For this example we want to have no outflow until the elevation in the reservoir reaches the spillway Since HEC 1 linearly interpolates between consecutive points on the elevation discharge and elevation volume curves we will trick it by
61. he time computation coverage to compute time of concentration and travel times and the land use and soil coverage to compute a composite CN value In the process you have also learned about the TR 55 interface CHAPTER 4 HEC 1 Interface WMS has a graphical interface to HEC 1 Geometric attributes such as areas lengths and slopes are computed automatically from the digital watershed Parameters such as loss rates base flow unit hydrograph method and routing data are entered through a series of interactive dialog boxes Once the parameters needed to define an HEC 1 model have been entered an input file with the proper format for HEC 1 can be written automatically Since only parts of the HEC 1 input file are defined in this chapter you are encouraged to explore the different available options of each dialog being sure to select the given method and values before exiting the dialog The US Army Corps of Engineers now supports HMS rather than HEC 1 but the hydrologic calculations for the options within HEC 1 have not changed Results of the two models will be identical 4 1 Objectives As a review you will delineate a watershed from a DEM You will then develop a simple single basin model using the delineated watershed to derive many of the parameters Land use and soil shapefiles downloaded from the Internet will be used to develop a SCS curve number CN value After establishing the initial HEC 1 model other variations will be d
62. ht of the SE option This time rather than creating a new curve you will select the elevation curve previously defined for the storage capacity curve 29 Select the Elevation curve from the Selected Curve drop down list 30 Select OK If you would like you may plot either the elevation discharge or the elevation volume curves by selecting the Plot SQ SE or Plot SV SE buttons This will bring the curve into a plot window that you can export print or control the same way you can a hydrograph or any other plot in a plot window 31 Select OK The last thing you need to input to define reservoir routing is the initial conditions of the reservoir The initial condition can be defined as an elevation a discharge or a volume with the data you just entered HEC 1 can determine the initial condition of the other two based on the one you enter For this example we will set the initial condition to an elevation four feet below the top of the spillway the spillway corresponds to elevation 6822 32 Under the Initial Condition Type select the ELEV option 33 Set the RSVRIC reservoir initial condition to be 6818 34 Select OK 35 Select Done 4 6 3 Running HEC 1 You are now ready to save and run the HEC 1 file with the defined reservoir 1 Select HEC 1 Run Simulation 2 Click the browse button next to the Input File 3 For the file name enter Reservoir and click Save this specifies the file name but does not actually save it 4
63. ial TTT 12 Commercial and Services EZZ 13 Industrial EZZ 14 Industrial and Commercial Complexes ZZ 16 Mixed Urban or Built up Land 17 Other Urban or Built up Land 21 Cropland and Pasture 23 Confined Feeding Operations b73 42 Evergreen Forest Land E 7 43 Med Forest Land SES 52 Lakes 53 Reservoirs 61 Forested Wetland PE 62 Nonforested Wetland 75 Strip Mines Quarries and Gravel Pits 76 Transitional Areas a AAS co CO a oe oVeu s Je e KNE po at 1 Figure 3 2 Land use codes used in Valdosta shp 3 3 2 Using the Compute Coverage Overlay Calculator 1 Switch to the Hydrologic Modeling module ae 2 Select Calculators Compute Coverage Overlay 3 Make sure that Drainage is chosen as the Input Coverage 4 Make sure that Land Use is set as the Overlay Coverage 5 Select the Compute button According to the USGS land use classification code values in the 50 s and 60 s represent water bodies To obtain the value for LK we sum together the computed overlay percentages for Land Uses 52 53 61 and 62 as shown in Figure 3 3 3 6 WMS Tutorials Volume 2 Overlay Areas and Percentages Basin Basin Basin Basin Basin Basin Basin Basin Basin Basin 15 Land Use 11 Land Use 12 Land Use 132 Land Use 14 Land Use 16 Land Use 17 Land Use 21 Land Use 23 Land Use 42 Land Use 43 10 26 17 46 04 49 84 01 04 PE r 2 10 8 1 Q 0 Q 0 0 2 0 7 0
64. in Figure 6 2 Rational Method Interface 6 11 Rational Method IDF Computation x IDF Curve Computation Hydro 35 Data Eastern US C NOAA Atlas Data Western US User Supplied Data PREFRE Data Maricopa Co Define Data Intensity Intensity 4 310 in hr Time of concentration lt min Specified tc te 22 0 Compute te Length 2352 66 Mannings n o 000 Slope 0 04268 Help Export IDF table Semin 10 min 15 min 30 min 60 min 5 640 4 590 6 504 5 370 3 680 2 675 4 561 1 720 3 280 216 10 pr aea e A a Taa 25 y 8 155 6 822 5820 4338 2912 5O y 8 940 7 507 6 411 4827 3 257 TOM oe ATIN nnn Tan caia arn IDF equation i 60 4093 Tc 12 4355 0 746003 Intensity Duration Frequency Curves 12 11 10 3 8 3 B i 4 3 2 1 o so ra on ma 30 ws mo zs DOD zrs mo Curationt Figure 6 2 IDF Computation Dialog with 10 yr Recurrence Interval Selected The rainfall intensity is determined from the selected interval by using the previously defined value for time of concentration 7 Compute i by selecting the Compute Intensity button 8 Select the Done button The value of i computed using the IDF Computation dialog will be placed in the edit field for this basin Note that the input for this basin is complete and a value for runoff Q has been computed The HYDRO 35 data only needs to be entered once unless differe
65. ing you may have to wait a few seconds to a minute or so The solutions will automatically be read in and you should see a small hydrograph plot to the upper right of the Basin icon now labeled as CCTrib T Double click on the hydrograph icon A plot window will appear with the hydrograph You will see that the hydrograph suddenly stops at 1500 minutes the duration of the simulation as established in the Job Control dialog but the simulation obviously has not run to completion 8 9 10 11 12 13 14 15 16 Close the plot window by selecting the X in the upper right corner of the window Select Hydrographs Delete All Select HEC 1 Job Control Set the Number of hydrograph ordinates to be 400 Select OK Select HEC 1 Run Simulation Select OK you can let it overwrite the other files Select Close once HEC 1 finishes running you may have to wait a few seconds to a minute or so Double click on the hydrograph icon You now have a completed HEC 1 simulation for a single basin and the resulting hydrograph should look something like the solution shown in Figure 4 2 HEC 1 Interface 4 11 Flow vs Time PEAK 488 18 TIME OF PEAK 890min VOLUME 12598963 35 500 ve Index 1 CCTrib 450 400 350 4 300 4 250 4 low 200 150 100 0 250 500 750 1000 1250 1500 1750 2000 Time Figure 4 2 Solution hydrograph for HEC 1 simulation 17 Cl
66. ing project file DEM Delineation 1 13 1 5 More Basin Delineation In this exercise you have learned the most basic use of WMS to delineate a watershed from a DEM It would be a good idea to practice again using a DEM of your own choosing In a previous chapter you were instructed to download your own DEM from the National Elevation Data Set site it would be good here to gain further practice by delineating a watershed using this DEM If you did not download a DEM or would like to try a different area go to the GSDA website at http xmswiki com wiki GSDA GSDA and follow the DEM links to download a DEM be sure to convert the format to GridFloat from ArcGrid before downloading Follow these steps using your own data using the previous sections for a more specific outline 1 Download your DEM data in the GridFloat format and unzip 2 Start WMS or choose the File New option if continuing 3 Load the DEM and convert from Geographic Coordinates to UTM NAD 8 amp 3 4 Crop out a portion of the DEM if it is much larger than the watershed you want to delineate you might want to wait and do this after the next two steps if you are unsure 5 Step through the Hydrologic Modeling Wizard and try locating the aerial and topo images that correspond to the DEM you downloaded 6 Delineate a basin and sub basins if you d like by stepping through the rest of the wizard 7 Experiment with some of the display settings to get a nice final
67. ing the X in the upper right corner of the window 6 3 Adding a Detention Basin If you compute runoff using the route by summing method then you can route hydrographs through detention basin structures defined at any of the outlet locations 1 Double click the outlet that defines the Small catchment in Figure 6 1 2 Select the Define Reservoir button in the Outlet column You will now define a hypothetical detention basin for the Small catchment from approximate geometric parameters WMS can compute a storage capacity curve for a rectangular basin You could also enter a pre computed storage capacity curve 3 Click the Define button 4 Select the Define Storage button 5 Select the Known Geometry option 6 Enter 200 feet for Length 7 Enter 300 feet for Width 8 Enter a Depth of 30 feet 9 Enter a Side slope of 2 10 Leave the Base elevation at 0 0 it will be assumed on grade at the outlet location 11 Select OK You will now define a standpipe and spillway weir for outlet structures and WMS will compute the elevation discharge relationship automatically In addition to standpipes and weirs you can define low level outlets or you can enter a pre computed elevation discharge relationship 12 Select the Define Discharges button 13 Select the Add Standpipe button 14 Set the Pipe diameter to 4 feet Rational Method Interface 6 11 15 Set the Standpipe elevation to 15 feet 16 Select the Add Weir button
68. ion a discharge or a volume For this example we will set the initial condition to an elevation HEC HMS Interface 5 21 four feet below the top of the spillway the spillway corresponds to elevation 6822 4 5 10 11 12 Set the Initial drop down to be Elevation Enter 68 8 for the Initial Value this should be the default already Select the Define Elevation Storage button Select New Change the name of the new curve to Elevation Storage In the first seven entry fields in the first column enter the following values 6803 6808 6813 6818 6821 99 6822 6825 feet of elevation In the first seven entry fields in the second column enter the following values 0 200 410 650 999 99 1000 1540 acre feet of volume Select OK Select the Define Storage Discharge button You will define separate XY series for Volumes Elevations and Discharges using the XY Series editor 13 14 15 16 17 18 Select New Change the name of the new curve to Storage Discharge In the first seven edit fields in the first column enter the values 0 200 410 650 999 99 1000 1540 acre ft of volume In the first seven entry fields in the second column enter the following values 0 0 0 0 639 99 640 7000 cubic feet per second of flow There is no outflow until the water reaches the spillway Select OK Select OK 5 6 3 Running HEC HMS You now have everything defined to run a three b
69. irectory and define a name for the file 3 Select Save The exported file can be viewed using any word processor or inserted into a separate report document 3 5 Time Computation Lag Time Calculation The NSS program provides a way to determine an average hydrograph based on the computed peak flow and a basin lag time A dimensionless hydrograph is used to define a basin hydrograph for the watershed based on the computed peak flow 1 Scroll down in the Results window if necessary and select the line of text corresponding to a Recurrence years of 50 2 Select the Compute Hydrograph button 3 Select the Compute Lag Time Basin Data button 4 Change the Method combo box to the Custom Method the very last one in the list 5 Select OK The computed lag time in minutes is shown in the lag time edit field Time of concentration equations can also be used to calculate the basin lag time WMS will convert the time of concentration to lag time by the equation Tiag 0 6 T 6 Select the Compute Lag Time Basin Data button 7 Change the Computation type combo box to Compute Time of Concentration 8 Change the Method combo box to the Kerby Method for overland flow 3 8 WMS Tutorials Volume 2 9 Select OK Note the difference in the calculated lag time between the two methods These two equations along with the other available options in the Basin Time Computation calculator can be used to estimate the lag time of
70. is usually indicates that the basin actually continues farther but was not properly delineated for some reason The other noticeable item is the gap in the flow accumulation cells It looks like the stream disappears for a while This is indicative of gaps in the DEM data 2 4 WMS Tutorials Volume 2 Figure 2 2 Delineation errors 1 Right click on DEM and select Display Options 9 2 On the DEM tab toggle No Data Cells on 3 Select OK No Data cells that interfere with the basin delineation as shown in Figure 2 3 Figure 2 3 No Data cells cause incorrect basin delineation 2 2 5 Fill Data Gaps 1 Select Display Frame Image Ed 2 Right click on the DEM in the Project Explorer and select Fill Editing DEMs 2 5 3 Select OK if an information message appears Notice that values were interpolated for the No Data cells lying in the interior part of the DEM 2 2 6 Run TOPAZ 1 Switch to the Drainage module 2 Select DEM Compute TOPAZ Flow Data 3 Select OK 4 Select OK 5 Select Close once TOPAZ finishes running you may have to wait a few seconds to a minute or so 6 Use the Zoom tool to zoom back in around the basin a The flow accumulation cells now connect all the way through as shown in Figure 2 4 Figure 2 4 New TOPAZ results after using the DEM Fill command 2 2 7 Basin Delineation 1 Select DEM Delineate Basins Wizard 2 If prompted select OK to delete all existing feature data and recr
71. m tool X 12 Create a zoom box around the region identified by a box in Figure 4 4 5 16 WMS Tutorials Volume 2 Figure 5 4 Zoom in on the area indicated by the rectangle 13 Select the Select Feature Vertex tool A 14 Select the vertex that is just below the feature node where the streams branch 15 Select DEM Node lt gt Outlet 16 Select the Frame macro H 17 Select DEM Delineate Basins Wizard 18 Select OK to delete and recreate feature data 19 Select OK 20 Select OK 5 5 2 Updating the Basin Parameters You will have to recompute the CN values and define precipitation and lag time for the basins 1 Select the Hydrologic Modeling module ae 5 5 3 HEC HMS Interface 5 17 2 Select Calculators Compute GIS Attributes 3 Select OK and the CN values will be updated for all basins they are actually very similar in this case because of there is one dominant soil polygon that covers the watershed 4 Close the Curve Number report Select the Select Basin tool iil Double click on the upper right basin icon to bring up the HMS Properties dialog Set the Show option to All 8 Change the name of the upper right basin to Right 9 Change the name of the upper left basin to Left 10 Change the name of the lower basin to CCTrib 11 Toggle on the Display of the Loss Rate Method and Show SCS Curve Number Because the CN values have been computed automatically you do not need to change anything here
72. map 8 Save a project file of your work 1 6 Conclusion In this exercise you should have learned how to use DEM data in WMS This includes the following 1 Importing DEM Data 2 Computing flow paths and flow accumulations 3 Delineating watersheds from DEMs 4 Delineating sub basins within a watershed CHAPTER 2 Editing DEMs Some terrain features including man made features such as roads canals reservoirs dams dikes and levees are not well represented in DEMs especially if the DEM resolution is coarse In addition it may be desirable to evaluate future alterations in terrain that result from development scenarios WMS has tools for editing DEM elevations and flow directions in order to include these features in the surface representation 2 1 Objectives In this exercise you will learn how to edit DEMs for more accurate surface representation and drainage analysis by completing the following steps 1 Filling gaps of data with the DEM Fill command 2 Using stream arcs to edit flow directions and modify delineations 3 Editing flow directions of individual DEM points 2 2 DEM Fill Command The DEM Fill command is useful for filling gaps in DEM data It interpolates missing values using inverse distance weighting of the neighboring eight cells After delineating an erroneous basin we will fill gaps in the data with the DEM Fill command recompute flow accumulations and directions and delineate the correct basin
73. me if we are only running the simulation once for a single basin Nevertheless if we plan to study many different basins on a regular basis then creating an NSS Region coverage for our state would prove to be very efficient 7 5 Conclusion In this exercise we have discussed the following concepts in conjunction with setting up an NSS simulation National Streamflow Statistics Program NSS Interface 7 7 How to calculate important parameters with the Compute Basin Data command How to use an NSS Region coverage to automatically determine which equations should be used and to compute any areas of NSS region overlap
74. n stream arcs 2 3 7 Basin Delineation 1 Right click on the DEM under the Terrain Data in the Project Explorer and select Display Options Y 2 On the DEM tab toggle on Flow Direction and Points toggle off Stream Flow Accumulation Color Fill Drainage Basins and Fill Basin Boundary Only 3 Select OK Notice that flow directions arrows for DEM points are visible but not necessarily for every DEM point because the display of flow directions is adaptive You will see more flow directions as you zoom in and fewer flow directions as you zoom out 4 Zoom in along the road until you can see flow direction arrows for every DEM point as shown in Figure 2 9 2 12 WMS Tutorials Volume 2 Figure 2 9 Flow direction arrows The flow directions arrows show that flow moves right over the road and into the stream on the other side of the road Watch how the flow directions change along that stream arcs that you added next to the road when you redefine the basins 5 6 7 10 11 12 13 Switch to the Drainage module Select DEM Define Basins Select Display Display Options 3 On the DEM tab toggle off Flow Direction and Points toggle on Stream Flow Accumulation Color Fill Drainage Basins and Fill Basin Boundary Only Select OK Zoom out until you can see the extents of the drainage basin HINT Scroll up on the mouse wheel to zoom out Select DEM Basins gt Polygons Select DEM Compute Basin
75. nd and open afrational h5 Select the Drainage module 8 Select DEM Compute Basin Data The Model units should be feet Set the Parameter units to be Acres for Basin Areas and Feet for Distances Select OK 6 2 Running a Rational Method Simulation The areas computed from the TIN can now be used in setting up a Rational Method simulation of the urban development Each of the outlet points represents an inlet to a storm drain 1 2 Select the Hydrologic Modeling module ae Select Rational to be the current model from the drop down list of models at the top of the screen Double click the basin icon for the basin labeled Upper in Figure 6 1 The Rational Method dialog should appear The parameters shown in the dialog correspond to the basin that was selected Rational Method Interface 6 11 Lower Middle Figure 6 1 Basins 6 2 1 Defining the Runoff Coefficients and Time of Concentration The runoff coefficient C is used to account for losses between rainfall and runoff The more developed a catchment is the higher the C value it will have 1 2 Enter a value of 0 20 for C Enter a value of 22 for Time of Concentration Click OK Double click on the basin labeled Small in Figure 6 1 Enter a value of 0 35 for C Enter a value of 6 for Time of Concentration Repeat this process for the other two basins using the table below to fill in values for C and te Runoff Coefficient C Tim
76. neation 1 Locate the icon for the Hydrologic Modeling Wizard at the bottom of your WMS window Click the icon to open the wizard 1 4 WMS Tutorials Volume 2 Project Filename Project Filename BeA Define Project Bounds Browse for project filename Watershed Data Download Data Web Service Read Data Catalog Compute Flow Directions and Choose Outlet Locations Delineate Watershed Select Model Job Control Hydrologic Computations Create 2D Grid Clean Up Model Figure 1 2 Hydrologic Modeling Wizard The Hydrologic Modeling Wizard window shown in Figure 1 2 consists of two sections The list box on the left shows the steps needed to set up your hydrologic model The area on the right displays specific tasks associated with the selected step Clicking Next gt on the wizard window will walk you through the steps of the wizard sequentially However you may skip to any step in the wizard at any time by clicking on the associated heading to the left 1 3 1 Project Filename 1 Make sure Project Filename is the current window in the Hydrologic Modeling Wizard 2 Select the file browser button to browse for a project filename 3 Name the project DemDelineation wpr and click Save 4 Click Next gt to advance to the next step 1 3 2 Define Project Bounds We will leave the project coordinate system the same as that associated with the DEMs we imported earlier 1 Under Project coordinate system select Define
77. ns by single clicking somewhere beyond the extents of the shapefile polygons Hide the statsgo shp file by toggling off its check box in the Project Explorer 4 2 5 Open the Land Use Data 1 10 11 Select the Land Use coverage in the Project Explorer to designate it as the active coverage Right click on GIS layers in the Project Explorer and select Add Shapefile Data Open _richut shp Choose the Select Shapes tool k Draw a selection box around the DEM extents Select Mapping Shapes gt Feature Objects Select Next Make sure the LUCODE field is mapped to the Land use attribute Select Next Select Finish Hide the _richut shp file by toggling off its check box in the Project Explorer 4 2 6 Convert Set the Coordinate System of the Data 1 2 Right click on Terrain Data in the Project Explorer and select Coordinate Conversion Under the Current Projection Section toggle on Specify 10 11 12 13 14 HEC 1 Interface 4 5 Make sure Global Projection is toggled on and click Set Projection Set Projection to Geographic and Datum to NAD 83 Select OK Set the Datum to NAVD 88 US and the vertical units to Meters In the New Projection section select Global Projection Click Set Projection Set Projection to UTM Datum to NAD83 Planar Units to METERS and Zone to 12 114 W 108 W Northern Hemisphere Select OK Set the Datum to NAVD 88 US and the vertical units to Meters Click
78. nt data is to be used for different basins so the rainfall intensity for the remaining basins can be defined using the following steps 9 Double click on the basin icon for Small 10 Select the Compute IDF Curves button 11 Select the line of text for the 10 yr recurrence interval 12 Select the Compute Intensity button 13 Select Done 6 6 WMS Tutorials Volume 2 14 Repeat these steps for the Middle and Lower basins 15 When you are finished entering the parameters choose Done on the Rational Method dialog 6 2 3 Defining Hydrographs As the data entry for each basin is completed a peak flow Q is computed and listed in the text display window The Rational Method equation does not produce a hydrograph However several different unit dimensionless hydrographs can be used to distribute the peak flow through time to create a runoff hydrograph 1 Double click the basin labeled Upper in Figure 6 1 2 Select the Compute Hydrographs button 3 Select the Rational method hydrograph from the drop down list 4 Select Done to compute the hydrograph 5 Select OK on the Rational Method dialog 6 Double click on the small hydrograph box to the upper right of the basin icon to open up a plot window of the hydrograph You should see the hydrograph displayed in a plot window as shown in Figure 6 3 6 2 4 Rational Method Interface 6 11 CT ox Flow vs Time PEAK 57 67 TIME OF PEAK 22min
79. nt tool from the wizard window 0 8 Place an outlet immediately downstream from the most downstream node you can see as shown in Figure 1 9 JEg f 4 i Figure 1 9 Change the indicated node to an outlet 9 Click Next gt to advance to the next step 10 Select Delineate Watershed 11 Click OK to delete the old basin boundary and create a new one 12 Click Cancel to close the Hydrologic Modeling Wizard DEM Delineation 1 11 1 4 Displaying DEMs 1 4 1 1 4 2 1 4 3 WMS has several options for displaying DEMs and the results of basin delineation from a DEM In this section you will explore a few of these options Move Basin Labels You may want to move the basin labels displaying the area slope etc to more convenient locations on the image 1 Make sure the Drainage module is selected and Choose the Move Basin Label tool E 2 Click on any area in the basin you just selected and drag the mouse to a location outside the basin before letting go of the mouse button An arrow will be drawn from where you let go of the mouse to where you started Turning Displays Off When you are finished using the elevation data you may want to turn the DEM contours and extra streams displays off 1 Right click on DEM in the Project Explorer and select Display Options Y 2 Uncheck the Flow Accumulation DEM Contours Color Fill Drainage Basins and Fill Basin Boundary Only options 3 Select OK Colo
80. optional It will teach you how to create an NSS region coverage that can be used to map equations for a given state using Florida as an example If you do not have a need or interest for this you do not need to complete it The NSS Region coverage type allows WMS to automatically determine which regression equations to use for an NSS simulation Additionally if a drainage basin overlaps multiple NSS regions the NSS Region coverage automates the calculations for the percentage of the watershed in each region You will now use an NSS Region coverage to automatically assign the region for an NSS simulation This coverage was digitized from an image that displays the NSS regions of Florida This image was obtained from the NSS documentation and you could make a similar map by scanning or capturing if electronic a map of the regions to create an image file registering the image to a recognized coordinate system digitizing the polygons most states have less than 10 regions so it would take only a few minutes to digitize and assigning the state and region Details on how to scan images and create polygons by digitizing are given in the chapters on images and feature objects see Volume 1 The USGS website http water usgs gov software NSS for NSS has images available in the state by state documentation of the equations that can be saved directly and then registered in WMS In this example we will read in an image that has already been register
81. ose the hydrograph window by selecting the X in the upper right of the window 4 4 Computing the CN Using Land Use and Soils Data 4 4 1 In the initial simulation you estimated a CN but with access to the Internet it is simple to compute a composite CN based on digital land use and soils files This was demonstrated in more detail in the Advanced Feature Objects exercise Volume 1 chapter 6 but you will go through the steps here as a review Computing a Composite CN In addition to the digital land use and soils file that overlap the watershed you must have a table defined that identifies CN values for each of the four different hydrologic soil groups A B C D This is described in detail at the gsda website http www xmswiki com wiki GSDA GSDA and in the Advanced Feature Objects exercise Volume 1 chapter 6 For this exercise you will read in an existing file you can examine it in a text editor if you wish and compute the CN numbers 1 Select the Hydrologic Modeling module ae 2 Select Calculators Compute GIS Attributes 4 12 WMS Tutorials Volume 2 3 Select the Jmport button to load the mapping table 4 Select OK to overwrite the current definition 5 Find and open the file named scsland tbl 6 Select OK to compute the CN from the land use and soils layers You should find that CN computed from the land use and soils digital data is about 72 or 73 While there is still some judgment required in
82. our curve 12 Select OK 13 Select OK 14 Select the Loss Method button 15 Enter a Curve Number CRVNBR field of 70 We will compute a CN value from actual land use and soil files later 16 Select OK 17 Select the Unit Hydrograph Method button 18 Make sure the SCS dimensionless option is chosen it is the default 19 Select the Compute Parameters Basin Data button 20 Set the Computation Type to Compute Lag Time the default 21 Set the Method drop down list to SCS Method near the bottom of the list 22 Select OK to update the computed lag time for the SCS dimensionless method 23 Select OK 24 Select Done You now have all of the parameters set to run a single basin analysis Running HEC 1 Whenever you run a HEC 1 simulation WMS will first save a standard HEC 1 input file You will also be prompted for the name of an output file and a solutions file The output file is the standard text output file generated by HEC 1 and the solution file is a plot file that contains the hydrographs formatted in a way that makes it easy for WMS to read and plot it is actually the HEC 1 TAPE22 file 1 2 Select HEC 1 Run Simulation Click the browse button L next to the Input File 4 10 WMS Tutorials Volume 2 For the file name enter CCTrib and click Save this specifies the file name but does not actually save it Verify that the Save file before run is toggled on Select OK Select Close once HEC 1 finishes runn
83. r two models the United States Geological Survey s USGS National Streamflow Statistics NSS and the National Resources Conservation Service s NRCS TR S55 will be discussed 3 1 Opening the Drainage Basin First we will open a WMS Project file wpr that contains a DEM that was previously downloaded from the Internet A single watershed basin has been delineated from the DEM data and converted to feature objects 1 2 Close all instances of WMS Open WMS Switch to the Drainage module 8 Select File Open Locate the folder C Program Files WMS8I tutorial nss Open NSS_FL wpr 3 2 WMS Tutorials Volume 2 3 2 Prepare the Basin for Use with NSS We will now use WMS to calculate the basin area basin slope and other parameters that can be used in conjunction with NSS 1 Select DEM Compute Basin Data 2 Select the Current Coordinates button 3 Set the Vertical units to Meters 4 Select Set Projection 5 Select METERS in the Planar Units Field 6 Select OK 7 Select OK 8 Set the Basin Areas to Square miles 9 Set the Distances to Feet 10 Select OK to compute the parameters In order to see the parameters that will be used with the NSS program you can turn them on for display 11 Select Display Display Options 3 12 Select Drainage Data 13 Check the display toggle for Basin Slopes Basin areas should already be on 14 Select OK Basin attributes are displayed at the centroid
84. r Filling Basins WMS also allows you to fill in each basin with a different color This is useful when the background image does not need to be showing 1 Right click on the Drainage coverage and select Zoom to Layer 2 Right click on the Drainage coverage and select Display Options Y 3 Check the Color Fill Polygons option 4 Select OK 1 12 WMS Tutorials Volume 2 1 4 4 Smoothing Boundaries If you zoom in near the boundary of one of your basins you will see that the boundary lines are not smooth because they are formed by tracing the DEM cells WMS allows you to redistribute vertices to smooth these boundaries 1 2 3 6 7 Switch to the Map module Choose the Select Feature Arc tool w Select Edit Select All Select Feature Objects Redistribute Select the Use Cubic Spline option Enter 100 in the Spacing edit box Select OK When you zoom in on the basin boundaries now they should be much smoother 1 4 5 Color Fill Contours WMS has several options for contouring DEMs 1 2 Select Display Display Options Y Toggle off the Color Fill Polygons option In DEM Data toggle on DEM Contours Click the Options button next to DEM Contours and change the Contour Method to Color Fill and click OK 1 4 6 Saving Your Work You can now resave your work as a WMS project 1 2 3 Select File Save As tal Save the file as DemDelineation wpr Select Save and OK to overwrite the exist
85. r each flow path segment You can change these equations and variables add new flow path segments etc in order to determine the best flow paths and most appropriate equations for each basin In other words the process is subjective and it may take a few iterations to get the best value 3 9 Computing Time of Concentration for a TR 55 Simulation Before assigning time of concentrations to each basin you need to decide which model you want to use For this exercise you will be running TR 55 but the same time computation tools you learn in this exercise could be used for any of the supported WMS models such as in the TR 20 basin data dialog the HEC 1 Unit Hydrograph method dialog and the Rational Method dialog 1 Select the Hydrologic Modeling module ae 2 Change the Model drop down list to TR 55 3 Select the Select Basin tool M 4 Select the basin 5 Select TR 55 Run Simulation In the TR 55 dialog notice the two drop down boxes at the top These provide the ability of changing TR 55 information for basins and outlets individually or collectively 6 Enter a Rainfall value of 1 5 7 Change the Rainfall distribution to Type IT 8 Select the Compute Tc Map Data button You will see the four time computation arcs that are in the basin 9 You can create a detailed report as a text file if you want by selecting the Export Data or Copy to Clipboard buttons 10 Select Done 11 Select OK Time of Concentration Calculations
86. rea and a weighted C value 6 8 WMS Tutorials Volume 2 10 11 12 13 14 15 16 Enter a value of 5 minutes for the Routing lag time Select the Compute IDF Curves button in the Outlet column Select the line of text for the 10 yr recurrence interval Select the Compute Intensity button Select Done Select OK Double click the outlet icon of Small Enter a value of 3 minutes for the Routing lag time Select the Compute IDF Curves button in the Outlet column Select the line of text for the 10 yr recurrence interval Select the Compute Intensity button Select Done Select OK Double click on the next downstream outlet the outlet icon of Middle Note that for this outlet the upstream areas are summed the C values weighted and the longest travel path computed from the upstream basin Tc s and travel times between outlets determined 17 18 19 20 21 22 Enter a value of 4 minutes for the Routing lag time Select the Compute IDF Curves button in the Outlet column Select the line of text for the 10 yr recurrence interval Select the Compute Intensity button Select Done Select OK The last or bottom most outlet does not need to have a Routing lag time defined since the hydrograph accumulations will occur at this point but you will still need to define the rainfall intensity 23 Double click on the bottom most outlet point Lower 24 25 26 27 2
87. s Volume 2 Table 2 1 New flow directions DEM Cell New Flow Direction RITITIN 7 8 Select OK Toggle on Compute flow accumulations ONLY after the last flow direction has been edited Select OK Repeat Step 1 5 for all numbered DEM cells in Figure 2 12 It is possible to edit the flow direction for multiple DEM points simultaneously using the DEM Point Attributes command in the Terrain Data module 2 4 2 Basin Delineation 1 2 4 X Switch to the Drainage module 8 Select DEM Delineate Basins Wizard If prompted select OK to delete all existing feature data and recreate using the new basin delineation Select OK Select OK The stream path and the geometric calculations for the basin affected by the stream path are now correct 2 5 Conclusion In this exercise you have learned some of the advanced basin delineation features that set WMS apart from other GIS based automated delineation techniques While this exercise illustrated only a few ways these tools can be Editing DEMs 2 17 applied proper understanding enables you to use the tools for many different scenarios where the automated delineation does not yield the results you expect CHAPTER Time of Concentration Calculations and Computing a Composite CN This exercise will discuss tools that are helpful in calculating the time of concentration and in computing a composite curve number CN In particula
88. setting up the mapping table there is a lot more justification for this value than the one previously estimated 7 Close the Curve Number Report 4 4 2 Running HEC 1 You can now run another simulation to compare the results with the modified CN value 1 Select HEC 1 Run Simulation 2 Select OK it is fine to overwrite the existing files but you can change the file names if you want 3 Select Close once HEC 1 finishes running you may have to wait a few seconds to a minute or so 4 Double click on the hydrograph icon to plot both the old and the new hydrograph in a plot window With the increased CN value you should see that the resulting hydrograph peaks higher more runoff The peak should be about 600 cfs rather than the 500 cfs that was generated with a CN value of 70 5 Close the hydrograph window by selecting the X in the upper right corner of the window 6 Select Hydrographs Delete All 4 5 Adding Sub basins and Routing You will now subdivide the watershed into two upper basins and one lower basin and define routing for the reaches that connect the upper basins to the watershed outlet HEC 1 Interface 4 13 4 5 1 Delineating the Sub basin 1 2 3 Select the Drainage module amp Select the Zoom tool X Create a zoom box around the region identified by a box in Figure 4 3 Figure 4 3 Zoom in on the area indicated by the rectangle 4 5 9 Select Display Display Options
89. ssigned to each arc and the Time of Concentration Calculations and Computing a Composite CN 3 9 time of concentration or lag time is the sum of the travel times of all arcs within a basin Lengths are taken from the length of the arc and slopes derived if a TIN or DEM are present In this exercise you will compute the time of concentration for the two sub basins and the travel time between outlet points in the watershed shown below You will use the TR 55 library of equations but you could just as easily use one of the other pre defined equations or enter your own equation 3 7 Reading a TR 55 Project You will first read in a project file of an urban area that has been processed and delineated as a single basin The project includes a drainage coverage a time computation coverage and two shapefiles for the land use and soil type data N 1 Switch to the Map module 2 Select File Open 3 Locate the folder C Program Files WMS8I tutorial r 55 4 Open suburbtr55 wpr 3 8 Assigning Equations to Time Computation Arcs A flow path arc has already been defined for the basin This arc represents the longest flow path for the urban area starting from a sandy area at the top of the basin following along the streets and down towards a detention pond at the bottom of the basin The arc has been split into four different segments to assign different equations to determine the travel time for the arc Use the following figure as
90. t ensure that input units are metric sq kilometers mm for rain meters kilometers for length and results will be in metric cms 8 Select OK For now we will leave the other Job Control settings at their default values Setting up the Basin Data Parameters In the first simulation you will treat the entire watershed as a single basin 1 Select the Select Basin tool M 2 Double click on the brown basin icon labeled 1B Double clicking on a basin or outlet icon always brings up the parameter editor dialog for the current model in this case HEC 1 3 Select the Basin Data button 4 Notice that the area has been calculated in this case in sq miles because we are performing calculations in English units 5 Change the name to CCTrib HEC 1 will only use the first SIX characters so do not use names longer than six characters for basins or outlets 6 Select OK 7 Select the Precipitation button 8 Select the Basin Average option 9 Enter 1 8 inches for the Average precipitation depth 10 Select the Define Series button In order to simulate a rainfall event you must enter both a rainfall depth and a temporal distribution The SCS uses standard time distributions for different areas of the U S These are stored in WMS You could also define your own 4 3 3 HEC 1 Interface 4 9 series according to an actual storm or a design storm from a regulating agency 11 In the Selected Curve drop down list select the typel 24h
91. te intervals We want to run this simulation for 25 hours at five minute intervals 6 Add one hour to the Ending time 7 Change the Time interval to 5 Minutes 8 Select the Basin Options tab 9 Enter Clear Creek Tributary in the Name field 10 Set the Basin Model Units to US customary English which should already be the default Setting the computation units DOES NOT cause any units conversion to take place You are simply telling HEC 1 that you will provide input units in English units sq miles for area inches for rain feet miles for length and 5 8 WMS Tutorials Volume 2 5 3 2 5 3 3 expect results of computation to be in English units cfs If you specify Metric then you must ensure that input units are metric sq kilometers mm for rain meters kilometers for length and results will be in metric cms 11 Select the Meteorological Options tab 12 Enter Clear Creek Tributary in the Name field You will note that HEC HMS includes advanced options for long term simulation and local inflows at junctions but we will not explore these options in this model 13 Select OK Setting up the Meteorological Data In HEC 1 precipitation is handled as a Basin Data attribute however for HEC HMS precipitation is defined separately in the Meteorological Data This is because of the ability of HEC HMS to model long term simulations that require additional information and often a lot more input 1 Select HEC
92. torials Volume 2 Number Outflow A z0 200 0 3 3 0 410 0 4 4 0 650 0 7 5 5 0 1000 0 i 6 60 1000 0 r 7 0 1540 0 8 8 0 9 9 0 1 2 3 4 5 6 7 L Number 10 10 0 11 11 0 Curve Name Volume 190 E Selected Curve Volume z New Delete Help Default Values Import Export Cancel Figure 4 5 The XY Series editor for inputting volumes 13 Select OK 14 Select the Define button to the right of the SE option 15 Select New 16 Change the name of the new curve to Elevation 17 18 19 20 21 22 23 24 25 In the first seven entry fields enter the following values 6803 6808 6813 6818 6821 99 6822 6825 feet of elevation Set the 8 through 20 fields blank instead of zero as with the volume series Select OK On the left side of this dialog you will define the Outflow or elevation discharge data Choose the Known Outflow option Toggle on the check boxes for SQ Discharges and SE Elevations Select the Define button to the right of the SQ option Select New Change the name of the new curve to Discharge In the first seven entry fields enter the following values 0 0 0 0 640 640 7000 cubic feet per second of flow There is no outflow until the water reaches the spillway HEC 1 Interface 4 21 26 Set the 8 through 20 fields blank instead of zero as with the volume series 27 Select OK 28 Select the Define button to the rig
93. ttributes Select OK and the CN values will be updated for all basins they are actually very similar in this case because of the dominant soil polygon that covers the watershed Close the Curve Number Report Select the Select Basin tool N Double click on the upper right basin icon to bring up the Edit HEC 1 Parameters dialog Select the Basin Data button Change the name to Right Select OK Move the Edit HEC 1 Parameters dialog out of the way if necessary and click on the upper left basin icon to edit parameters for the upper left basin Alternatively you could select Done and then double click on a basin to obtain the Edit HEC 1 Parameters dialog Select the Basin Data button Change the name to Left Select OK Move the Edit HEC 1 Parameters dialog out of the way if necessary and click on the lower basin icon to edit parameters for the lower basin Select the Basin Data button Change the name to CCTrib Select OK Select Done 4 16 WMS Tutorials Volume 2 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Select Edit Select All to select all basins Select HEC 1 Edit Parameters to edit parameters for all basins at once Select the Precipitation button Select the Basin Average option Set the Average Precipitation to be 1 8 in Select the Define Series button Choose the typell 24hour curve in the Selected Cur
94. ve drop down list Select OK Select OK Select the Unit Hydrograph Method button Make sure the SCS dimensionless option is chosen it is the default Select the Compute Parameters Basin Data button Select CCTrib in the Basin window so that it is highlighted Select the method to be SCS Method near the bottom of the list Select Right in the Basin window so that it is highlighted Select the Method to be SCS Method near the bottom of the list Select Left in the Basin window so that it is highlighted Select the method to be SCS Method near the bottom of the list Select OK Select OK Select Done 4 5 3 Setting up the Routing Parameters If you were to run HEC 1 now you can if you want you would see that the hydrographs from the upper basins would be combined with the lower basin hydrograph at the watershed outlet without any lag or attenuation because you have not yet set the routing parameters You will now define a routing method HEC 1 Interface 4 17 which will instruct HEC 1 to compute lag and attenuation on the upper basin hydrographs before adding them to the lower hydrograph Routing for a reach is always defined at the upstream outlet of the reach in WMS 1 Select the Select Outlet tool amp chee 2 Double click on the outlet the yellow circle icon of the upper right basin Select the Routing Data button 4 Select the Muskingum Cunge method for routing 5 Set the width WD field to be 5 five feet wide 6

Watershed Modeling - The University of Texas at Dallas

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