From Gsshawiki

Preface

This document and the software GSSHA™ are products of the Watershed Systems Group, Hydrologic Systems Branch, Coastal and Hydraulics Laboratory, Engineer Research and Development Center. For more infor-mation about GSSHA™ contact:

Barbara Parsons
Hydrologic Systems Branch
Coastal and Hydraulics Laboratory
Engineer Research Development Center
3909 Halls Ferry Rd.
Vicksburg, MS, 39180

Barbara.A.Parsons@erdc.usace.army.mil

http://chl.erdc.usace.army.mil/GSSHA

Disclaimer: GSSHA™ is a reformulation and enhancement of the hydrologic model CASC2D. The CASC2D hydrologic model is Copyright 1995, 1996, 1997, 1998 by Fred L. Ogden, 1995 by P.Y. Julien and B. Saghafian. No part of this documentation may be reproduced without complete citation. The GSSHA™ code is continuously being improved. Changes in the source code and input/output requirements of GSSHA™ may be made by the authors at any time, without notice. No claims are made regarding the suitability of GSSHA™ for any purpose. The model GSSHA™ is written for research and educational purposes. Use GSSHA™ at your own risk. GSSHA and Gridded Surface Subsurface Hydrologic Analysis is a trade-mark of the U.S. Army Corps of Engineers.

Most of the images were produced by the Watershed Modeling System (WMS), which is copyrighted by Brigham Young University, 2008 and used under license. For more information on WMS please refer to http://www.aquaveo.com.

Microsoft and Excel are registered trademarks of Microsoft Corporation in the United States and/or other countries. No endorsement is made by Microsoft Corporation of this work or as to the suitability of Excel® for any of the processes described in this document

1   Initial Overland Flow Model Setup

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Initial Basin Setup

To start a GSSHA™ model, you must have a digital elevation model and a boundary polygon for the watershed. For this tutorial we will use a DEM as the elevation model and also create the boundary polygon and the streams. WMS uses the DEM to interpolate cell elevations and the boundary polygon to select whether or not a cell is active (inside the basin) or inactive (outside the basin.) Unlike lumped parameter watershed models, the basin should not be subdivided into sub-basins. There should only be one basin boundary. The following steps are the same steps used to begin all watershed models in WMS. For more information, consult the WMS 8.0 Tutorials.

Open the DEM (select the Judys_branch.hdr file in the DEM folder. At the ‘Importing NED BIL File’ dialog, click ‘OK’. When the convert coordinates now dialog pops up, say yes and then turn on the ‘Edit project coordinate system’. Convert from the Geographic NAD 83 to UTM NAD 83 and pick the UTM Zone 16.)

1. Click ‘OK’.
2. Highlight Watershed icon.
3. Use TOPAZ by selecting DEM | Compute TOPAZ Flow Data.
4. After running TOPAZ, locate the outlet. The outlet location is shown in the following figures. Using the zoom tool zoom into the area shown in the following figure and locate the outlet.
5. Create an outlet point using the ‘create outlet’ feature . Make sure this point is on the ‘blue’ stream line.
   
   

   Figure 1. DEM contours of the area. The boxed area shows where the outlet should be located.
   
   
   

   Figure 2. A close up of the outlet area shown in Figure 1. The outlet feature node must be located on a DEM stream cell.
6. Create the Basin and Stream Arcs using the Delineate Basin Wizard. This is found in the DEM file menu. Use a threshold value of 0.2. The finished basin should look like the following figure.
   
   

   Figure 3. The watershed boundary after delineation by WMS and TOPAZ.
7. Save your project.

Initial Grid Setup

The basic GSSHA™ model begins with the basin boundary in the Drainage coverage and a DEM. It is helpful to have the streams already set up as well, but not necessary. In this step you are essentially telling WMS to take the boundary polygon and the DEM and create a 2D grid that fits the boundary and has an elevation data set that is interpolated from the DEM. For more information on selecting appropriate cell sizes see the GSSHA™ Primer. (http://chl.erdc.usace.army.mil/software/GSSHA™/Primer_20/wf_njs.htm)

1. Begin from Basin Setup (You can load the delin_basin.wpr file in the Finished_tutorials\delin_basin folder if you are starting from here.)
2. In the Map Module , using the Select Polygon tool , select the basin boundary polygon.
3. Select Feature Objects | Create Grid… (Select Yes for GSSHA™ grid.)
4. Select the second toggle, the one for base cell size, and enter 90 (meters.) Select OK.
   
   

   Figure 4. The Create Grid dialog in WMS. Select the second bullet and enter a base cell size.
   
   
5. Hit OK on the Background Elev Interpolation dialog.
   Hit Yes on the Delete Existing Background DEM dialog. The basin should now look like the following figure.
   
   

   Figure 5. The regular grid created for the GSSHA™ simulations.
   
   You’ll notice in the data tree that the Drainage coverage has now changed name (and changed type as well) to the GSSHA™ coverage. A 2D Grid called new grid is also in the tree now.
   
   

   Figure 6. The Drainage coverage changed type to the GSSHA™ coverage and the 2D Grid Data now has a gridded data set group in it.
   
   

Job Control Setup

In the last step, the GSSHA™ Job Control parameters were initialized using the default values, which are mostly zero. It is best to start with some realistic values.

1. In the 2D Grid module select GSSHA™ | Job Control …
2. Enter an outlet slope of 0.001.
3. Enter a time step of 10 (seconds) and a total run time of 500 (minutes).
   
   

   Figure 7. The GSSHA™ Job Control dialog. To begin, you need to enter a total time, time step, and the outlet slope.
   
   
4. Select OK.

Uniform Index Map Setup

Once the Job Control parameters are set to more realistic values, there are two main areas to set up for overland flow. First, the overland flow roughness coefficients need to be set and secondly, the precipitation data needs to be specified. There are two parts to setting up the overland flow roughness coefficients; first an index map must be set up that describes the spatial variation of the roughness and secondly, the roughness values themselves must be set. We shall create a spatially uniform set of roughness values.

1. Select GSSHA™ | Maps… (Notice that an Index Map Folder was created when the grid was created.) This will bring up the GSSHA™ Index Maps dialog.
   
   

   Figure 8. The GSSHA™ index map dialog. Use this dialog to create index maps from GIS coverages.
   
   
2. Select Data Calculator. This will bring up the Data Calculator dialog.
   
   

   Figure 9. The Data Calculator is used to create index maps containing uniform values.
   
   
3. In the Expression box, type 1.
4. In the Result box, type Uniform
5. Check the ‘Index map’ option
6. Select Compute.
7. Then, select Done. This takes you back to the Index Map dialog.
8. Select Done.

We have just populated an index map (a grid) with the value 1. If you expand the data tree you will notice that our new index map has been added to the index maps folder under the 2D grid folder.

Figure 10. Notice the new index map is placed in the index map folder.

Roughness Table Setup

Notice that when we made the index map we assigned a value of 1 to the whole map. The 1 is an index number, and we shall now relate the index number to a roughness coefficient. This is done through the mapping table.

1. Select GSSHA™ | Map Tables...
2. Select the Roughness tab.
3. In the Using Index Map combo box select “uniform”.
4. Select Generate IDs.
5. In the ID field, type 1
6. In the Surface Roughness edit field, enter a value of 0.1.
   
   

   Figure 11. The Mapping Table editor. This dialog sets up the bulk of the GSSHA™ input parameter for each process used.
   
   
7. Select Done.

The tabs on the Mapping Table dialog list some of the mapping tables that can be set up. We will set up other mapping table processes in future tutorials. Through these two steps we have set up the spatial variability of the roughness value (by assigning it the uniform index map) as well as assigned roughness values to the IDs in the map.

Setting the Uniform Precipitation

Besides the roughness, the precipitation must be set up in order to run the basic model. GSSHA™ can run multiple events in long-term mode only, so for now we will set up a single rainfall event. To simplify the process, we will set up a simple uniform precipitation event for a short duration.

1. Select GSSHA™ | Precipitation …
2. Select the Uniform Rainfall Option.
3. Enter the rainfall intensity of 10 (mm/hr).
4. Enter the rainfall duration of 60 (minutes).
   
   

   Figure 12. The GSSHA™ Precipitation dialog is used to set up both uniform events and gaged events.
   
   
5. You can change the start date/time to be what you like.
6. Select OK.

Save the GSSHA™ Model

It is advisable to create a new folder each time a significant revision is made and save the project in it. Unfortunately, there is no way to make a new folder in the current save project file dialog and this must be done externally. Once you have made the new folder, if desired:

1. Select GSSHA™ | Save Project File…
2. Browse to the folder where you wish to save the project.
3. Enter file name.
4. Select Save.

Typically, most of the files share a similar base file name and only differ in extension. The exceptions to the rule are the index maps, which all have the same extension and different base file names. The file names and extensions may be any name desired; the defaults given in WMS are merely convention, but they do aid in quickly identifying files when you are rummaging through them. The following table lists a few of the extensions used by convention.

Running the Model

1. Select GSSHA™ | Run GSSHA™
2. Select OK.

After looking through the output, you’ll notice that not a lot of water ran off the watershed. Often at this point in the development the simulation will not run to completion. The problem is usually due to digital dams. Digital dams are artificial depressions in the 2D Grid that cause water to pond. How to fix digital dams is the subject of a following chapter.

2   Visualizing Overland Flow Results

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Working with Results

Since we have just run our first simulation, it would be nice to see what happened! You’ll notice that after you hit close on the Model Wrapper that WMS automatically read in some files. WMS stores the results of a run together as a solution set (the input data is not a part of the solution, only the output data.) There can be many solution sets in the data tree but they must be for the same grid and streams. For example, you could have solution sets for different roughness parameters or different time steps and then you can compare results across the data sets. If you are just starting at this tutorial, first load the initial project:

1. In the 2D Grid module , select GSSHA™ | Open Project File
2. Browse to the basic_ov.prj file in the Finished_tutorial\basic_ov folder of the GSSHA™ tutorial folder.
3. Hit Open.
   
   
   In order to open a project you must select a *.prj file. The project file is the primary file that tells WMS and GSSHA™ what options are set up and which files should be read or written. The project file lists both the input files as well as the output files that GSSHA™ will read and write during a run. Thus the project file doubles as the solution file. In order to open the solution (if you did not run GSSHA™ in the previous chapter or you are starting over):
   
   
4. Select GSSHA™ | Read Solution…
5. Make sure that the simulation points to the right simulation (basic_ov.prj in this case.)
   
   
   Notice that beneath the Select Simulation button WMS has a line that says “Solution file: GSSHA™ Solution files found.” What this means is that WMS has opened the project file listed above, read in what should have been the output file names, tried to open those files, and found at least one that exists. If you have not run the simulation yet or GSSHA™ was not able to run, then the dialog will say that the solution files are not found.
   
   
6. Select OK.
7. Expand the ‘new grid’ 2D grid folder in the data tree
8. Expand the ‘basic_ov (GSSHA™)’ folder.
   
   
   Notice that on the ‘basic_ov (GSSHA™)’ folder icon, there is an ‘s’ for solution. Now that we have a solution read in we can do many things. First, though, let’s look at the summary file.
   
   
9. Double-click on Summary File under the solution folder.
10. If WMS asks for your editor just click OK.
11. Look through the summary file. It is good to check things like mass balance and the volume remaining on the surface.
12. When you are done you can close the window.
    
    
    From the summary file we learned that most of the water remained on the grid instead of running off. There could be a couple of reasons for this. Maybe the simulation did not run long enough, or there are problems with the elevation grid, or both. Let’s look at the water depths to determine what happened during the run.
    
    
13. In the 2D Grid module select Display | Display Options
14. Turn on the 2D Grid Contours.
15. Select OK.
16. In the data tree, right-click on Depth under the solution folder.
17. Select Contour Options.
18. Under Contour Method select 'Color Fill.'
19. Select OK.
    
    
    Underneath the data tree a set of time steps appear. Click around on a few. It would be helpful if we knew what the colors represented.
    
    
20. Right-click on Depth in the data tree.
21. Select Contour Options.
22. Turn on the legend.
23. Click OK.

Creating a Movie

Click around some more on the time steps. Try panning, zooming, and rotating. You can also adjust the lighting (Display| Display Options | Lighting Options) and the vertical exaggeration (Display | View | Z Magnification.) Let’s make a movie of the contours. Once you get a view that you like:

1. In the 2D Grid module select Data | Film Loop…
2. Make sure that Create New Film loop and Scalar/Vector Animation are selected. Hit next.
3. Turn on the Depth Scalar Data Set. Hit Next.
4. Hit finish. Wait for WMS to build the movie.

Once the movie is created and playing you can adjust the playback speed, looping, etc.

Now that we have a movie of the runoff depths, it is fairly easy to see that the water has stabilized by the end of the run to sit in many little puddles on the grid. These puddles are the result of the digital dams. Thus our lack of runoff is not due to time constraints (currently, anyways) but due to the presence of digital dams.

3   Fixing Digital Dams

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Working with Digital Dams

The problem with digital dams is that the water gets stuck in a cell where it shouldn’t be ponding. There are three methods to fix the digital dams. The first method is to manually adjust the cell elevations. The second method is to use the Cleandam™ tool to smooth the cell elevations. Cleandam™ is an automated tool, but you will have to decide whether or not the results are reasonable. To quickly identify which cells have digital dams:

1. Select Display | Display Options.
2. In the 2D Grid tab, click on Digital Dams.
3. Select OK. The Grid will look something like the following image.
   
   

   Figure 14. The digital dams are marked.
   
   
   
   To better visualize why these cells are digital dam cells:
   
   
4. Select Display | Display Options.
5. Under the 2D Grid tab, select the blocked cells toggle.
6. Turn on the 2D Grid Contours, Elevations, and Flow Vectors.
7. Click on the 2D Grid Contours Options button.
8. Choose Color Fill Contours and hit the OK button.
   
   

   Figure 15. The Display Options dialog controls what is shown.
   
   
   

   Figure 16. The contour options dialog controls how the data sets are displayed. Each gridded data set has its own set of contour options.
   
   
9. Hit OK.
10. Use the Rotate, Pan, and Zoom tools to look at a digital dam cell.
    
    

    Figure 17. 3D view of how cells are represented in GSSHA™. This display helps to visualize the problems with the digital dams.
    
    

The black dots denote the digital dam cells. The arrows point out the downward slope between the cells. The cells with all four sides marked as pointing inward are flagged as digital dam cells. The blocked cells display option helps to illustrate this. You can use the Display | View | Z Magnification option to enhance the z scale.

Manually Adjusting Cell Elevations

The most straight-forward method for removing digital dams is to manually adjust cell elevations to make the water flow in an appropriate direction. There are a few tools in WMS to help with this process. In the display options dialog, under the 2D Grid tab, you can turn on elevations, flow directions, and digital dams. Usually the digital dams’ option is turned on first and then you would zoom into a trouble area. Once zoomed in you would turn on the elevations and flow directions to help visualize and understand where the trouble spots are. Occasionally only the digital dam cell has to be adjusted but usually one or more neighboring cells are the source of error. To adjust the elevation of a cell, click on the cell, edit the cell elevation in the Properties window, and hit the Enter key to register the elevation change. Individually editing cell elevations is still an option in WMS, but this option is infrequently used because of the existence of the Cleandam™ elevation smoothing program.

Using Cleandam™ to Fix Digital Dams

Manually adjusting cell elevations works fine for small basins with a few digital dams or if there is one or two particularly troublesome digital dams in a larger watershed model. It quickly becomes tedious, however, when there are hundreds or thousands of digital dams. This is why Cleandam™ was created. Cleandam™ uses a stochastic search process to find the best path from the digital dam to a lower elevation. It does this by starting from the digital dam and randomly searching from cell to cell until it finds a lower cell elevation. A cost function is then calculated which is the difference between the current cell elevations along the path and a linear sloping path from the digital dam and the cell with the lower elevation.

The algorithm does n² searches over 2n x 2n patch sizes. The n starts out at 8 and if a lower cell is not found then the patch size grows progressively larger until it reaches 256. Once a completed path is found on a patch size, all the completed paths for that patch size are compared to see which one results in the least amount of cutting. The best one is then selected and the cell elevations in the grid are edited to conform to the new path. This process generally favors passing through nearby digital dams as well, so these digital dams are fixed as a by-product of fixing the first digital dam and are called “soft fixes.” You’ll see this as the results of the Cleandam™ program are printed out.

To run Cleandam™:

1. Select GSSHA™ | Clean Digital Dams…
2. If WMS can’t find Cleandam™.exe, browse to it in the GSSHA™ subfolder of the WMS folder.
3. You should now see Cleandam™ running in the model wrapper. When it is done look at the output and hit close.

4   Using the Mapping Table and GIS Data

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Using Land Use Data

So far in our model we have set up uniform roughness and precipitation conditions. Setting up non-uniform precipitation will be covered in a later chapter. We shall now look at setting up spatially varied roughness coefficients. Describing the spatial variability of almost all parameters is done through setting up an index map and a mapping table. The index map is a grid of ID numbers. The ID numbers refer to numbers in the mapping table. Index maps are generic and may apply to any number of tables. Each table lists the name of the index map associated with the table and all the IDs that the index map (should or could) have, along with parameters for the IDs. We will be using a land use GIS file to create the IDs for the index map to be used with the roughness table.

1. Start from where the previous chapter ended or you can open up the clean_ov project in the Finished_tutorial/clean_ov folder. (If you starting from here, you will notice in the Coverage that Land Use already exists.)
2. Select File | Open…
3. Browse to the Landuse folder in the project folder.
4. Click on jb_luse_poly.shp. Click Open. The shapefile will be added as a GIS layer (not a feature object coverage).
5. Right-click on Coverages and select New Coverage.
6. Change the Coverage Type to Land Use. Click Ok.
7. Make sure the Land Use coverage is the current active coverage by clicking on it in the Coverage list.
8. Select the jb_luse_poly.shp GIS layer by clicking on it. Notice that this changes the active module to the GIS module.
9. Select Mapping->Shapes to Feature Objects.
10. Click yes on when asked to use all shapes in visible shapefile for mapping.
11. Click Next.
12. Click Next to accept the default attribute mappings.
13. Click Finish.



Figure 21. Creating a new coverage in the data tree.



We now have a land use coverage in WMS. Zoom into the GSSHA™ model area. You can turn off the display of the jb_luse_poly.shp GIS layer by unchecking the box next to it. Using the Select Polygon tool double-click a polygon inside the grid. The land use mapping dialog will open. Notice that there are 10 land use types.




Table 3. USGS Land Use codes. [ref]

USGS Land Use Codes 11 Residential 12 Commercial and Services 14 Transportation, Communications, and Utilities 16 Mixed Urban or Built-up Land 17 Other Urban or Built-up Land 21 Cropland or Pasture 41 Deciduous Forest Land 43 Mixed Forest Land 53 Reservoirs 76 Transitional Areas




Now we can make an index map out of the land use coverage. The index map will be used to describe the spatial variability of roughness values for the simulation.



14. Switch to the 2D Grid Module .
15. Select GSSHA™ | Maps…
16. For the coverage use the Land Use coverage. Do not use a second GIS data source.
17. Change the Index map name to Land Use.
18. Click on Coverages -> Index Map.
19. Select Done.



If you expand the 2D Grid part of the Data Tree you’ll notice that there are now two index maps listed, uniform and Land Use. Let’s visualize them as well.



20. Click on the ‘uniform’ index map in the data tree.

The grid should appear solid red. This is because the uniform map is all ones.

21. Click on the ‘Land Use’ index map in the data tree.



The grid should now have cells colored in several colors representing the IDs of the polygons that were mapped to the grid cells. Next we will assign the Land Use index map to the roughness table and set up roughness values for each of the IDs in the Land Use index map.



22. Select GSSHA™ | Map Tables…
23. Select the Roughness tab if it is not already selected.
24. Under Using index map choose the Land Use index map.
25. Click on Generate IDs. Click yes when asked to delete the process’ existing IDs.
26. Fill out the Roughness values according to the table below. To enter a roughness value for an ID, highlight the surface roughness box below the ID then edit the roughness value. (You may also edit the descriptions if you wish, however you should leave the original polygon ID description as is.)



Table 4. Roughness values corresponding to Land Use

ID Description Roughness 11 Land ID #11, Residential 0.08 14 Land ID #14, Highway 0.07 21 Land ID #21, Cropland and Pasture 0.35 41 Land ID #41, Deciduous Forest Land 0.20



27. Once you are done, select Done.



You can now save the model and run the simulation.

5   Stream Flow

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Creating GSSHA™ Stream Arcs

At present the GSSHA™ streams are generic and have no defined geometry. To specify a stream size, we will need to supply dimensions for each stream arc in the Judy’s Branch basin. If you are beginning at this tutorial:

1. In the 2D Grid module select GSSHA™ | Open Project File.
2. Browse to the Finished_tutorial\land_use folder and select the land_use.prj file and click Open.
3. In the Project Explorer select the GSSHA Coverage.



In WMS, the tools for working with 2D grid data are in the 2D Grid module. The tools for working with the stream data are in the Map module. In order to set up the stream model four things must be done. The stream arcs must be set to a GSSHA™ stream arc type, the stream thalwegs refined, the stream geometry defined, and the channel routing job control item set.

Because of the way we set up the GSSHA™ basin, we have in the GSSHA™ coverage a set of stream arcs. These stream arcs, however, are currently set to be generic stream arcs instead of a type that can be used in GSSHA™.



4. Select the map module of WMS .
5. Click on the “Select Branch” tool .
6. With this tool selected, click on the stream segment labeled “#1” on the following figure to select all streams.

Figure 22. Stream Link numbers.


7. Select Feature Objects | Attributes…
8. Toggle on “Trapezoidal Channel” which allows you to define stream geometry for the stream arcs.
9. Fill out the edit fields according to the following table.



Table 5. Initial stream shape and roughness parameters for all streams. Parameter Value Manning's N 0.07 Bottom Width (m) 8 Channel Depth (m) 8 Side Slope (m/m) 2



10. Click OK.

Now all the stream arcs in the basin are defined as trapezoidal channels, and have identical geometries. There are two types of channels that GSSHA™ recognizes, trapezoidal and break-point. It would be nice if we could add some variation to our streams in order to represent the streams narrowing upstream. To do this we will change the dimensions of the upstream arcs.

11. Switch to the “Select Arc” tool to modify streams one segment at a time.
12. Double-click stream segment “#2” as shown in the previous figure.
13. Enter the values for depth, width, roughness and slope as shown in the following table.
14. Repeat steps 11 and 12 for stream arcs 3 through 27.

Table 6. Stream shape and roughness values for individual streams.

Arc Number Channel Depth (m) Bottom Width (m) Roughness Side Slope (m/m) 2 5 5 .075 2 3 2 2 .08 2 4 5 5 .075 2 5 3.5 3.5 .08 2 6 2 2 .08 2 7 2 2 .08 2 8 5 5 .075 2 9 2 2 .08 2 10 5 5 .075 2 11 2 2 .08 2 12 5 5 .075 2 13 2 2 .08 2 14 3.5 3.5 .08 2 15 2 2 .08 2 16 3.5 3.5 .08 2 17 2 2 .08 2 18 3.5 3.5 .08 2 19 2 2 .08 2 20 2 2 .08 2 21 5 5 .075 2 22 2 2 .08 2 23 5 5 .075 2 24 2 2 .08 2 25 3.5 3.5 .08 2 26 2 2 .08 2 27 2 2 .08 2




The stream arcs now have defined geometries and are ready to be smoothed.

Smoothing the Stream Arcs

Now that the geometry for each stream arc has been defined, it is important to ensure that each arc is flowing downhill. Due to inaccuracies in the DEM data, stream arcs will occasionally flow uphill, which causes digital dams and other problems. To alleviate this dilemma, we will look at the stream profiles and modify the point elevations until each arc is flowing downhill. First, however, we need to redistribute the vertices on the arcs to a more reasonable spacing.

1. Select the map module .
2. If the Model combo box on the X, Y, Z edit bar is not set to GSSHA™, change it to GSSHA™.
3. Click on the Select Branch tool .
4. Click on the stream segment labeled “#1” on the figure below to select all streams.

Figure 23. Stream link numbers.


5. Select the Feature Objects | Redistribute.
6. Type 90 in the box next to Spacing and click OK.
7. Pick the Select Arc tool .
8. Select arc # 1 as shown on the figure above, and while holding down the shift key, select stream arcs “#2” and “#4”
9. With these streams selected select GSSHA™ | Smooth Stream Arcs…

In the Smooth GSSHA™ Streams dialog you will see a profile of the arcs you have selected. Notice that while the segment has a general downward trend, in some places the streambed is significantly adverse. While GSSHA™ is able to handle adverse slopes, it is not desirable that adverse slopes should be in the model where they do not exist in life. We will mitigate this problem by making slight changes to the vertex and node elevations along the segment.

10. In the pop-up window, click on the “Interpolate stream elevations” buttons as many times as needed to generate a smooth stream segment with no uphill flow, then click OK.
11. If uphill flow cannot be eliminated in this manner, you can edit individual points by selecting the “select a point” tool , then dragging the point to a new position or editing the value in the box next to “Stream elevation.” Be especially careful to make sure the nodes next to the outlet are not adverse.
12. Click and drag around a point in the display to zoom in on individual points and modify them.
13. You can also use the scroll bars in the plot window to move along the zoomed stream segment.
14. Once the stream segment you have selected is smooth, select a new stream segment or combination of segments to smooth.
15. Repeat the smoothing process outlined in steps 8 through 14 until all arcs in the basin are smooth.

Your streams are now ready for use in the GSSHA™ model.

There is one last step before saving the model. The stream routing option must be turned on in the Job Control dialog.

16. In the 2D Grid Module Select GSSHA™ | Job Control….
17. Under Channel Routing toggle on Diffusive Wave.
18. Select the Output Control button.
19. Under Link / Node data sets toggle Channel depth and Channel flow on.
20. Click OK.
21. Click OK.



Save the model and run it.

6   Visualizing Stream Data

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

While the streams are connected to the overland flow plane they are separate models each having their own input files and data formats. The streams output data in a format is called the link/node data set format. These files hold a data value for every link and node at the same time step as that for the gridded output data. The two most common files in this format are the channel depth file (*.cdp) and the channel discharge file (*.cdq.)

The link/node data set files are read in with the other solution files and the data tree will place a reference to them in the solution folder under the 2D grid. Since they are not data to be visualized on the 2D grid there are a couple of steps to visualize the data. The link/node data sets are visualized on a TIN. The TIN is made from the stream arcs and the stream boundaries around the streams. The process of making the TIN also copies the link/node data sets to the TIN.

To make the TIN, a solution set must be in memory that has valid link/node data sets. If you are just starting this lesson:

1. In the 2D Grid module select GSSHA™ | Open Project File…
2. Browse to the Finished_tutorial\streams_trap folder.
3. Select the streams_trap.prj file and select Open.
4. Select GSSHA™ | Run GSSHA™ and select OK to run the simulation
5. After GSSHA is finished running click on the Close button and the solution will be read
6. Verify that GSSHA™ has finished running and that the Read solution on exit toggle is checked. Click the Close button to close the run and read the solution.



If you expand the streams_trap solution in the 2D Grid folder you’ll see a Depth data set as well as the summary file. We can look at the Depth file using the methods in the second chapter. You can also see the Stream Depth and Stream Flow data sets in the 2D Scatter Data folder. The Stream Depth and Stream Flow data sets are stream link/node data sets.

In order to visualize these we need to turn on the contours for the 2D Scatter Data.



7. Select either the Stream depth or the Stream flow data set in the 2D Scatter Data folder in the data tree
8. Open the Display Options dialog.
9. Turn on the contours for the 2D Scatter Data.
10. Select a radius and Z Magnification (try a radius of 50 and a Z magnification of 50).
11. Click OK. Select a time step other than the first one in the Properties window.



You should be able to see colored circles along the stream links. The color represents the value of the data point. If you rotate into 3D mode, you will see that the circles are actually the tops of cylinders. In the properties folder you will see the time steps. As you select individual time steps the data for that time step both the 2D grid data and the 2D scatter data will be contoured. If you switch to the 2D grid module, you can select Data | Film Loop... and create a film loop of the stream and grid data.

7   Break-point Cross Sections

This tutorial is compatible with:

• WMS Version 8.1
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Not only does the GSSHA™ model allow you to define trapezoidal cross sections, it also allows you to import cross sections from survey data. Using cross section data can make your model more realistic, and help you achieve better calibration. The process is relatively simple, and the following exercise will show you how this can be done.

If you are beginning at this tutorial:

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Finished_tutorial\streams_longer folder.
3. Select the streams_longer.prj file and select Open.



Just as when we set up the trapezoidal cross sections for the streams, all of the stream tools are in the Map Module.



4. Select the Map Module .
5. Click on the Select Arc tool .
6. Double-click on arc “#1” as defined in the following figure.
7. Toggle Irregular cross-section channel to enable the use of survey data.
8. Click on the Define Cross Section Parameters button.



You should now see the XY Series Editor window, which is where you will enter the cross section data (notice the spreadsheet on the left side of the window, with columns labeled “X” and “Y”). The cross section data you will be entering into this spreadsheet is located in an Excel® file, which you will copy from and paste into the “XY Series Editor”.



9. Open the Excel® file “xsections.xls” in the Xsec_data folder.
10. Copy the data for cross section #1 located in cells “A2” to “B35” (this data corresponds to cross section #1 in the following figure.
11. Paste this data into the top-left cell of the WMS “XY Series Editor” spreadsheet by right-clicking on the cell and selecting “paste”.
12. Select OK, then OK again.
13. Double-click on arc “#2” as defined in the following figure.
14. Repeat steps 4 through 9, except this time copy the data from “#2” in the Excel® spreadsheet.
15. Repeat step 11 for the stream arcs #4, #8, #10, #12, #14, #16, #21, #23, #25, and #27 (we do not have survey data for all the streams).
16. All streams in the basin now have either survey geometry or trapezoidal geometry for their cross sections.
17. Save the GSSHA™ project by selecting the 2-D Grid Module .
18. Click on the GSSHA™ | Save Project File.
19. Navigate to the folder you would like to save the project in.
20. Enter desired project name.
21. Click Save.

Figure 24.

Adjusting the Stream Course

1. If you do not already have the background image displayed, display them now by selecting File | Open…, navigating to the Judys_Branch_tutorial/Images folder, and opening all 21 carbon.jpg files. (You can filter them by typing *.jpg in the file name field before you select any.)



If we zoom in around the main freeway interchange we can see where the TOPAZ delineated streams do not follow the actual streams. Additionally, the natural stream course has been altered by the presence of the interchange.




Figure 25.



We will adjust the stream course to reflect the true location of the stream.



2. Zoom in around the interchange shown in the above image.
3. In the Map Module select the Select Feature Vertex tool .
4. Adjust the vertices of the arc to be similar to the following image.



Figure 26.



Once the arc has been adjusted we need to make sure that the node spacing is right.



5. Using the Select Feature Arc tool select the stream arc.
6. Select Models | GSSHA | Smooth Stream Arcs.
7. Select Redistribute vertices...
8. Enter 90 as the spacing value. Select OK.
9. If needed, smooth the stream. Once you are done select OK.

Adding an Embankment

One unique aspect of the Judy’s Branch basin is that it has a freeway bisecting it. This freeway acts as a barrier or embankment, which inhibits overland flow. To accurately model the basin, we need to take the embankment into account. The following exercise will show you how this can be done.

1. Select the GIS module of WMS .
2. Right click on GIS Layers in the Project Explorer and select Add Shapefile Data...
3. Browse to the Embankment folder, and open the EmbankmentArc.shp file.
4. Click the GSSHA Coverage to make it active
5. Click on the EmbankmentArc.shp file in the Project Explorer
6. Select Mapping | Shapes->Feature Objects
7. Click Yes to use all shapes
8. Click Next, Next, and Finish to map the Embankment Arc shapefile to a GSSHA Embankment Arc.
9. Toggle off the EmbankmentArc.shp file in the Project Explorer



You should see the embankment arc running across the center of the watershed. Although the embankment arc is shown in its proper geographic location, the elevations at each vertex need to entered manually. We'll adjust the vertex display settings to see them better.



10. Open the Display Options dialog
11. Click on Map Data in the left panel
12. Click on the button displaying the vertex icon and change the radius to 5 and the color to yellow.
13. Click OK to close the Display Options dialog.
14. Click on the GSSHA coverage to view the Map Tools
15. Choose the Select Feature Vertex tool.
16. Using Figure 27 as your guide, select each vertex of the embankment arc and assign it the corresponding elevation in the properties window on the right.



Figure 27. Embankment arc elevations at each vertex


17. Select the “Select Arc” tool .
18. Double click on the embankment arc to bring up the Feature Arc Properties window
19. Click the Edit Embankment Profile button.
20. View the embankment arc profile and notice the two ending points of the embankment arc are still zero.
21. Click OK to close the Embankment Arc Profile Editor
22. Click OK to close the Feature Arc Properties window



Since we created the embankment arc using a shapefile, the embankment arc nodes did not snap to the watershed boundary. First we'll snap the embankment arc to the watershed boundary, then we'll assign elevations at the two nodes.



23. Choose the Select Feature Vertex tool
24. Right click on the vertex that lies on top of the node where the embankment arc meets the watershed boundary
25. Select Clean
26. Click OK in the Clean dialog
27. The embankment arc node is hidden by the watershed boundary. Click again in the same spot as the vertex. WMS will then snap the vertex and node together.
28. Repeat for the node on the opposite end of the embankment arc
29. Choose the Select Feature Node tool.
30. Click on the node where the embankment arc meets the watershed boundary
31. For the node on the left side of the watershed, assign an elevation of 165.
32. For the node on the right side of the watershed, assign an elevation of 178.
33. Choose the Select Arc tool.
34. Double click on the embankment arc.
35. Click the Edit Embankment Profile button to view the embankment profile. Notice the profile looks much smoother now.
36. Click OK, and OK to return to the WMS window



WMS uses the embankment arc to define cells edges as overland flow barriers. You can view these cell edges in the Display Options dialog .



37. In the 2D Grid module select Display | Display Options…
38. Turn on embankments and cells. Click OK.
39. Zoom in on the embankment arcs.



You should see the cell edges nearby highlighted in red. These red edges are the actual embankments that GSSHA™ uses. If there are any gaps in the embankment edges, you will need to adjust the embankment arcs accordingly. Note, if the embankment arc, a black line by default, coincides with one of the cell edges it may appear that the line is broken when in fact it is continuous. An example of this is shown in the second image below. If the embankment arc is broken, an entire cell will lack the red highlighting. For example, if you see a problem similar to the first image below. (if you have done everything correctly, you will probably not need to do this):




Figure 28.

Figure 28a - Embankment arc crossing highlighted cell edges giving the false appearance of a broken embankment arc.



It is because the embankment arcs are not snapped together or do not extend far enough. To fix the problem:



40. In the Map Module , zoom in on the problem spot.
41. Using the Select Feature Node tool select the end node on either of the arcs that do not connect.
42. Right-click on the selected node, select the clean command, make sure the option to snap selected nodes is on, and select OK.
43. At the lower left corner of the screen, you are prompted to select a snapping point. You should select the end point of the other arc for snapping. After selecting this point, the arcs will snap together.
44. Select the Refresh button to update the display of your embankment cells.

Adding Structures

Due to the embankment we created in the previous exercise, water from the top half of the model will only be able to reach the outlet by flowing through the streams that pass through the embankment. To control the amount of water that passes through the stream at the embankment we will create a structure (in this case a culvert), at a node where the stream arcs intersect the embankment. The following steps outline how this is to be done.

1. Select the map module .
2. Pick the Select Feature Point/Node tool .
3. Using the figures below as a reference, double-click on the point (node) where the two streams intersect and cross the highway.



Figure 30.


4. In the “Node Type” section of the Feature Node Attributes dialog, click on the drop down box and select Link Break.
5. In the Hydraulic Structure and Curves section of the Feature NodeAttributes dialog, click on the Culvert button to add
6. Click on the word “Culvert 1” that appears in the text box below “Hydraulic Structures and Curves”.
7. Select the drop-down box next to culvert type and select “Rectangular”.
8. Enter the following values to define the culvert:



Table 7. Culvert parameters. Culvert #1 Box width (m) 2.40 Box Height (m) 2.40 Upstream Invert (m) 154.0 Downstream Invert (m) 153.8 Inlet loss coeff 0.50 Loss coeff (rev.) 0.50 Length (m) 10.00 Roughness 0.025



9. Click OK.

Once you have finished the culvert, save the model and run it.

8   Infiltration

This tutorial is compatible with:

• WMS Version 8.1
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Infiltration is a key loss mechanism in a watershed; no watershed model is complete without it. GSSHA™ has four different infiltration models. During this tutorial you will set up the inputs needed for the Green & Ampt with Soil Moisture Redistribution model.

If you are starting at this tutorial,

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Finished_tutorial\streams_embank folder.
3. Select the streams_embank.prj file and select Open.

Index Map Setup

Importing the Shapefile as a GIS Layer

The first step that needs to be done is to set up an index map that describes the spatial variation in parameters needed by the infiltration model. We shall use a soil type shapefile from the SSURGO database of the area to create a soil type index map. Before we do anything with the shapefile in WMS, though, let’s look at it so that we know what we are working with.

1. Launch Microsoft® Excel®.
2. Select File | Open.
3. Browse to the Soils folder of the GSSHA™ tutorial data.
4. Using the control key, select both the soil_clip.dbf and IDs_for_WMS.dbf files. Select open.
5. If soil_clip.dbf is not the active worksheet change to it by selecting Window | soil_clip.dbf.



This is the attribute data that comes in the shape file. Notice that there are four parameters, ‘areasymbol’, ‘spatialver’, ‘musym’, and ‘mukey’. What WMS is looking for is a parameter that will serve as the soil type ID. There is not a suitable one in this file.



6. Switch to the IDs_for_WMS.dbf worksheet by selecting Window | IDs_for_WMS.dbf.



This dbf (dbase IV) file has been created to provide the information that WMS needs for the soil_clip shapefile to be useful. Usually when setting up a GSSHA™ model the soils data base file needs to be manipulated so that it has a number that indicates a soil classification. Notice that the previous symbols are there, although the number of lines of data is greatly reduced. Additionally four parameters have been created, ‘newid’, ‘classifica’, ‘erosion’, and ‘descriptio’. Looking at the ‘classifica’ and ‘descriptio’ parameters we can see that the soils were grouped according to soil type classification.

Table 8. Soils type classifications. Classification Description 1 Urban Land complex 2 Silt Loam 3 Silty clay Loam 4 Fine sand 5 Silty Clay 6 Water




First we want to bring in the soil_clip shapefile as a GIS layer. You can close Excel® and switch back to WMS.



7. Select Edit | Current Coordinates...
8. Select Set Projection.
9. Ensure the coordinate system is set to UTM, NAD83, Meters, Zone 16.
10. Select OK.
11. Select OK.
12. Right-click on GIS Layers in the data tree.
13. Select Add Shapefile Data.



Browse to the Soils folder and open the soil_clip.shp shapefile. This shapefile is added as a GIS layer; however it is not “officially” part of your project. It can now be converted into a WMS coverage in a much simpler manner, however before we convert it to a WMS coverage, we want to join the IDs_for_WMS.dbf file to it.



14. Right-click on soil_clip.shp in the data tree.
15. Select Join Table To Layer.
16. Open the IDs_for_WMS.dbf file.
17. Under Shapefile Join Field select mukey.
18. Under table data field select classifica.
19. Select OK.
20. Right-click on soil_clip.shp in the data tree.
21. Select Open Attribute Table.
22. Make sure that the classifica field was added to the table and hit Ok.



The next step is to create the soil type coverage in WMS to receive the polygons.



23. Right-click on Coverages in the data tree.
24. Select New Coverage…
25. Change the Coverage Type to Soil Type.
26. Hit OK.



Now we can convert the shapefile to a coverage.



27. Make sure the Soil Type coverage is the current active coverage by clicking on it in the Coverage list.
28. Select the soil_clip.shp GIS layer by clicking on it. This will change the active module to the GIS model .
29. In the GIS Module select, Mapping | Shapes -> Feature Objects.
30. Select Yes for use all shapes in visible shapefiles.
31. Select Next.
32. Scroll over to the Classifica column.
33. In the drop-down box that says ‘not mapped’ change it to be ‘SCS Soil type’
34. Hit Next and then Finish.
35. Wait for WMS to convert the shapefile into the coverage.

Cleaning up the Soil Type Coverage

Let’s visualize the soil type coverage.

1. In the 2D Grid Module select Display | Display Options.
2. Turn off all of the 2D Grid options except the boundary.
3. Click OK.
4. In the Data Tree, uncheck the land use and GSSHA™ coverages.
5. In the Data Tree, select the Soil Type coverage.
6. Select Display | Display Options.
7. Switch to the Map Data tab.
8. Under the Polygons field, turn on the Color Fill Polygons.
9. Select Soil Type Display Options.
10. Set up the colors and patterns to make them more visible. Pick colors similar to the following image. Select OK when you are done.
11. In the Points/Nodes area, turn off the Points/Nodes and the Vertices.
12. In the Legends field, turn on the Soil Type legend.
13. Select OK.



Figure 31. Initial soil types in the watershed.


Based on the earlier description of the soil types, soil type 1 is classified as a reworked residential area. Soil type 6 is classified as water. In order to assign soil properties to soil types 1 and 6 we will edit the polygons with these soil types and change them to have the the soil type of the neighboring polygons.


14. Using the Pan, Zoom, and Select Polygon tools change the soil polygon IDs for Soil ID 1 (cyan) and Soil ID 6 (blue) to be what their neighbors are. This is accomplished by double-clicking on the desired polygon. This will bring up the Soil type mapping dialog as shown in the figure below. The soil type ID is changed in the WMS soil ID field. Click ‘Apply’
15. Repeat step 14 for all the soil polygons of type 1 and 6.



Figure 32. Changing a soils type mapping.

Setting up the index map

Now we can make an index map out of the soil type coverage. The index map will be used to describe the spatial variability of the infiltration parameters for the simulation.

1. Switch to the 2D Grid Module .
2. Select GSSHA™ | Maps…
3. For the coverage use the Soil Type coverage. Set the Coverage attribute to be ID. Do not use a second GIS data source.
4. Change the result name to Soil Type
5. Click on Coverages -> Index Map
6. Select Done.



Now we have an index map of the soils shapefile. Now we need to turn on the infiltration parameters in the Job Control.



7. In the 2D Grid module select GSSHA™ | Job Control.
8. In the Job Control dialog change the infiltration option to Green + Ampt with Soil Moisture Redistribution.
9. Click OK.



Now we can set up the mapping tables for infiltration.



10. In the 2D Grid Module select GSSHA™ | Map Tables….
11. Select the infiltration tab.
12. In the Using index map box choose Soil Type.
13. Select Generate IDs.



The Generate IDs from Map button created three IDs, 2, 3, and 5. You will recall from when we created the land use index map that these three IDs came from the polygon IDs 2, 3, and 5. So the soil type index map ID #2 represents silt loam soils; the index map #3 represents silty clay loam; and the ID #5 represents silt.



14. Using the following table, enter the values for each parameter.

Table 9. Soil properties. ID Description Hyd. Conductivity (cm/hr) Capillary Head (cm) Porosity (m3/m3) Pore Dist. Index (cm/cm) Residual Saturation (m3/m3) Field Capacity (m3/m3) 2 Silt Loam 0.68 16.68 0.501 0.234 0.015 0.33 3 Silty Clay Loam 0.20 27.30 0.471 0.177 0.040 0.366 5 Silty Clay 0.10 29.22 0.479 0.150 0.056 0.387



15. Select the Initial Moisture tab in the process window.
16. In the Using index map combo box select the uniform map.
17. Select Generate IDs.
18. Enter a value of 0.3 for the initial moisture.
19. Click Done.



You can now save the model and run.

Visualization

Since no water ran off we can guess that it all infiltratated. But let’s check to make sure.

1. In the data tree, under the solution that was just read in, double-click on the summary file.
2. Verify that there are no mass balance errors, check the amount that it rained and the amount that infiltrated, and close the file.



Since we need more water lets increase the precipitation.



3. In the 2D Grid Module select GSSHA™ | Precipitation.
4. Increase the precipitation rate to 25 (mm/hr).
5. Select OK.



Let’s also turn on the infiltration output options.



6. Select GSSHA™ | Job Control
7. Select Output Control...
8. Turn on Cumulative Infiltration Depth and Infiltration Rate.
9. Select OK.
10. Select OK.



Save and run the simulation. You can now use the same techniques from Chapter 2 to visualize the infiltration data sets.

One of the more interesting movies you can make is of the Infiltration Depth data set (To turn this dataset on, open the GSSHA Job Control window, click on Output Control, and toggle on the Cumulative Infiltration depth dataset. The two different soil types saturate at different rates and make for a pretty impressive movie.

9   Long-Term Simulations

This tutorial is compatible with:

• WMS Version 8.1 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Long-term simulations typically involve running several rainfall events along with the evapotranspiration model for weeks to months. There are two key parts to running a long-term simulation. The first is to set up the precipitation file, and the second is to set up the evapotranspiration model with its hydrometeorological (hmet for short) data.

Precipitation

A long-term event typically consists of multiple rainfall events, often with several rain gages. Multiple gage events can either be setup using WMS or using a handy Microsoft® Excel® spreadsheet. If you are only passingly familiar with Microsoft® Excel® it is recommended that you read Chapter 10, “Using Microsoft® Excel® to format GSSHA™ Data” first.

We will start by using a Microsoft® Excel® spreadsheet to set up a multiple-event, single gage precipitation file from some raw data.

Using the Format Precip Macro

1. Navigate to the "Formatting Macros" folder.
2. Open the Excel® file “format_precip_macro.xls” and enable macros, if prompted.
3. Click on the worksheet titled “input_data”.
4. Select columns “A” through “F”.
5. Right-click on the columns and select “Format Cells…”
6. In the “Format Cells” pop-up window select “Text” in the box below the word “Category”.
7. Click “OK”.
8. Use Notepad to open the file “precip_raw.txt”, located in the Precip_data folder.
9. Select and copy the entire text file.
10. Select cell “A1” on the input_data worksheet, then right-click and pick “Paste”
11. Set up the data to match the format outlined on the “Instructions” worksheet of the spreadsheet (for help look at the instructions, or refer to Chapter 10 Using Microsoft® Excel® to format GSSHA™ Data.
12. Follow the steps on the “Instruction” worksheet. (Use the default values. The coordinate for the gage is found in the Precip_formatted.txt file.)
13. Once you have setup the data, click on the “Format precip data” button found on the “Instructions” worksheet”.
14. Your formatted data is on the “Output_data” worksheet.

Hydrometeorological Data

Hydrometeorological data is used in GSSHA™ to determine how the soil moisture is affected by atmospheric conditions. The hydrometeorlogical data is used to drive the evapotranspiration model. In the following exercise we will create a file that contains all the hydrometeorological data for the same period as the precipitation data.

Using the Format Hmet Macro

1. Open the Excel® file “Format_Hmet_macro.xls” from the Formatting_macros folder, and enable macros if prompted.
2. Select the “Instructions” worksheet to learn how the data should be organized before it can be formatted for GSSHA™.
3. To retrieve the raw data, open the Hmet raw data file called “Hmet_raw.xls” in the Hmet_data folder.
4. Select the “KBLV_Scott worksheet and copy the appropriate columns of raw data to the “input_data1” worksheet of the format Hmet data macro.
5. Select the worksheet “scott_radiation_2001” of the raw data file, and then copy the appropriate columns to the “input_data2” worksheet of the format Hmet data macro.
6. Make sure that the “input_data1” and “input_data2” worksheets are organized as outlined on the “Instructions” worksheet, and then click the “Format Hmet data” button on the “Instructions” worksheet. (Note that the Instructions indicate that the data should be entered in cell A1. This is an error. The first row of data should be in cell A2.)
7. The formatted data will be shown on the “output_data” worksheet.
8. Save the “output_data” worksheet as a text file called “hmet.txt” in the folder you created earlier in the precipitation section.

Evapotranspiration

Now we will go back to WMS and set up the Long-term modeling data. First we need to set up the Job control options to turn on long-term mode.

If you are starting the tutorial from here, open the long_term.prj file found in the Finished Tutorial folder.

1. Select GSSHA™| Job Control…
2. Check the box next to "Long term simulation" in the GSSHA Job Control Parameters window.
3. Click the Edit parameter... button and enter a value of 38.7696 for “Latitude”.
4. Enter a value of 270.05 for “Longitude”.
5. For “GMT” enter a value of –6.00.
6. Enter 0.10 for “Minimum event discharge”.
7. Make the “Soil moisture depth” equal to 0.5.
8. Click on the folder icon to next to “HMET Data File” to browse for the Hmet text file you created with the “Format_Hmet_macro” spreadsheet. Navigate to the file and select it.
9. Under “Format”, toggle on WES.
10. Select OK.
11. In the “Evapotranspiration” section of the window toggle “Penman Method”.
12. In the Overland Flow Computation method combo box choose “ADE” instead of “Explicit.”
13. Select OK.



Next we need to set up the ET parameters.



14. Select GSSHA™ | Map Tables…
15. Click on the Evapotranspiration tab.
16. In the drop down box next to “Using index map” select landuse, then click the “Generate IDs” button.
17. Enter the values required for evapotranspiration using the following table, or you can find values from the appendix.



Table 10. Values for the Evapotranspiration process. ID# Albedo Wilting Point (m3/m3) Vegetation Height (m) Vegetation Transmission Coefficient Canopy Stomatal Resistance (s/m) 12 0.15 0.1 0.08 0.7 20 15 0.22 0.1 0.1 0.5 20 22 0.22 0.1 1 0.2 86 42 0.2 0.1 17 0.15 100



18. Click Done.



Next we need to tell WMS to point to our precipitation file.



19. Select GSSHA™ | Precipitation…
20. Select Gage from the drop-down menu.
21. Click the Import Gage File… button.
22. Browse to the precipitation file, select it, and hit OK.



Since we only have one gage, the rainfall data is spread out uniformly over the watershed. If we had more that one gage we would pick either Theissen Polygons or Inverse Distance weighted here in this dialog.



23. Select Ok.



We are ready to run now, but first we will want to change some output options. We will not want to output the data sets so frequently.



24. Select GSSHA™ | Job Control...
25. Click on the Output Control... button.
26. In the Write frequency section of the dialog, change the Write Frequency to 60 (minutes).
27. Select OK, OK.



You are now ready to run a long-term simulation. Save the project, then run GSSHA™. This simulation may take some time to run to completion, and will run faster by selecting the Suppress screen printing option in the GSSHA Run Options dialog. You may view the simulation output by clicking the Abort button, selecting GSSHA | Read Solution and opening the sol_long_term.prj from the long_term_sol folder in the Finished_Tutorial directory.

10   Using Microsoft® Excel® to format GSSHA™ data

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Splitting an Excel® column

In this example you will copy a text file from Notepad and paste it into Microsoft® Excel® where it can be manipulated and formatted. Specifically, you will take information from a single column and split it into multiple columns using two different methods.

1. Use Notepad to open the file titled “date1.txt”, located in the Excel_Tutorial folder.
2. Highlight all the data starting with the first row down to the final row.
3. Copy this data by right-clicking on the highlighted data and selecting “copy”.
4. Open a Microsoft® Excel® worksheet and select the entire first column by clicking on the “A” at the top of the column.
5. Right-click on the “A” column and select “Format Cells”.
6. In the “Category” box pick text, and then click “OK”.
7. Select cell “A1”, then right-click on the cell, and select “paste”.



You will notice that the data has been pasted so that the year, month, and day values are contained in a single column. To make it so that each value has its own column, you will use the “Text to Columns…” command.



8. Select the entire column by clicking on the letter “A” directly above the column.
9. Select the “Data” menu and click on the “Text to Columns…” command (this will bring up the “Convert Text to Columns Wizard”).
10. Because the data is separated by the character “/”, toggle “Delimited” and select “Next”.
11. Check the box titled “Other” and type the “/”character (without quotation marks) into the box provided to the right of the “Other” delimiter.
12. Click “Finish” to exit the wizard.



You should now see three columns that represent values for year, month, and day.

The preceding example shows how data can be separated based on a delimiter such as a comma, space, or other character. However, not all data has a distinct character that divides values. In cases such as these it becomes necessary to divide data based on width. The following steps illustrate how this may be done.



13. Use Notepad to open the file titled “date2.txt”, located in the Excel_Tutorial folder.
14. Repeat steps 2 – 9 (above.)
15. Toggle “Fixed width” and click “Next” (because the data is not separated by any distinct characters, we divide the column based on width.)
16. In the “Data preview” window, create a break line between the year and the month by clicking between the 2 and the 1 on any row, and then make another break line between month and day by clicking between the 1 and the 0.
17. Click “Finish” to exit the wizard.



You should now see three columns that represent values for year, month, and day.

Note

When copying and pasting data from Notepad into Excel®, it is useful to format the destination column to be “text” before you paste—the text format will not alter a number or delete zeros that precede a number. Also, make sure the cells to the right of the column you are dividing are empty.

Using the AutoFilter

In this exercise you will be utilizing the AutoFilter option to locate various cells in an Excel® spreadsheet and modify them.

1. Open the Excel® file “filter.xls”.
2. Select column “C” by clicking on the “C” at the top of the column.
3. Click on the “Data” menu and select “Filter”, then select “Auto-Filter”.
4. You will see a small box with a black arrow inside (the AutoFilter box) appear in the first cell of the column. Click on the AutoFilter box.



The dropdown menu that appears under the AutoFilter box shows the unique values of all the cells below the AutoFilter box. By selecting one of the values you are determining which rows will be displayed, and which rows will be hidden.



5. Scroll to the bottom of the AutoFilter dropdown menu and select “(Blanks)” to display the blanks cells in column “C”.



All rows that do not have blank values in column “C” have been hidden. The row numbers for the remaining rows have been changed to blue in-stead of black.



6. Enter the number “0” in the first blank cell of Column “C”.
7. Repeat step 6 for each cell in column “C” that has a row number written in blue (you can use the AutoFill capabilities of Excel® if you wish).
8. Click on the AutoFilter box again and scroll to the top of the menu, then select “(All)” to show all rows.



Now there are no blank cells in column “C”.

The AutoFilter can be used in a variety of ways, and the following exercise will walk you through additional uses. Let’s say we are only interested in looking at the precipitation values that are larger than 0.1. The following example shows how we can customize the display options of the Auto-Filter.



9. Click on the AutoFilter box in the first cell of column “C”.
10. In the AutoFilter dropdown menu select “(Custom…)” to modify which cells you would like to display.
11. Click the top-left drop down box and select “is greater than or equal to” for the AutoFilter to display all rows that are greater than or equal to the value you specify.
12. In the next box over (to the right) type “0.1” (without quotation marks.)
13. Select “OK”.



Now you can view all the cells in column “C” that have values of 0.1 or lar-ger. If you want to delete the cells smaller than 0.1 you would have to change the custom filter to display the cells less than 0.1, then you could select the displayed rows and delete them.

Find And Replace

The find and replace command can be very useful when formatting data. This tool can be used to delete, replace, or modify cell values. The following exercise will show you how to use the replace command, as well as how it can be applied to formatting data.

1. Open the Excel® file “replace.xls”.
2. Select column “C” by clicking on the “C” at the top of the column.



In column “C” you will notice that the values are hours of the day, followed by a “z” which stands for “Zulu” or Greenwich time. If we want to use these numbers in GSSHA™ we will have to remove the “z” from each cell. To do this we could split the column, however, using the replace command works equally as well.



3. Select the “Edit” menu, and then click “Replace…”
4. In the text box below “Find what:” type “z” (without quotation marks.)
5. Leave the text box below “Replace with:” empty, which means that the “z” in each cell will be replaced with nothing.
6. Select “Replace All” to replace all the z’s in column “C” with noth-ing.



Instead of replacing the z’s with nothing, you could have replaced it with a letter or a number. If you wish, try repeating the exercise, and at step 5 enter in a number or word or whatever you would like. The replace com-mand can be used to replace words, letters, or numbers, in rows or in col-umns.

General Information

The following commands can be useful when formatting data in Excel®

• Saving an Excel® file as a text file
  • Make your active sheet the one you would like to save as a text file.
  • Select the “File” menu, and pick “Save As…”
  • Enter a new name for the file in the box next to “File name”.
  • Select the drop down box for the “Save as type” and pick: “Text (Tab delimited) (*.txt)”.
  • Then click “Save”.
  • Click “OK” at the prompt.
  • Select “Yes” at the next prompt.
  • The text file will be saved in whatever folder you specified.

• Moving Columns
  • To move an entire column, click on the letter at the top of the column.
  • The entire column will be selected, with two heavier black lines on either side of the column.
  • Put the pointer over one of these heavier dark lines, then when the cursor changes to an arrow, click on the black line.
  • While holding down on the left mouse button, drag the column to the destination of your choice.

11   Manual Calibration

This tutorial is under construction. Attempt at your own risk. The files referenced in this tutorial are not available, although any valid GSSHA™ project file and solution can be substituted.

This tutorial is compatible with:

• WMS Version 8.1
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

We shall practice calibrating a simplified model. It does not have ET or long-term turned on. This data set is more to help you become familiar with the WMS interface for manually calibrating your own model than it is to end up with a calibrated model. If you have WMS running, close it and open up a new instance.

1. In the 2D Grid Module, select GSSHA™ | Open Project File…
2. Browse to the Finished_Tutorials/calibrate/start folder. Open the base_calib.prj file.
3. Select GSSHA™ | Read Solution… Make sure that the base_calib.prj file shows up in the dialog. Hit Ok.



This is the project we shall use as the starter project. Let’s look at the data.



4. Zoom in around the outlet. You’ll notice a short stream that connects the outlet to the rest of the stream network.
5. In the Map Module, using the Select Feature Node tool, double-click the node at the upstream side of that short segment.
6. Click on the Observations button.



This dialog (shown in the following figure) is used to compare solution results with each other and with the observed data. Let’s load the observed data.



7. Open up Microsoft® Excel®. Open the observed.xls workbook in the Finished_tutorials\calibrate folder.
8. Copy cells A2 to B202.
9. In WMS, in the Observations dialog, select the drop-down box under the observed column in the upper pane. Select the Edit field.
10. Paste the data into the XY Series editor. Look at the plot of the data and click OK.



Notice that under the observed data column, in row 1, it says ‘Show.’ The show and hide commands alter the display of the data in the two plots in the lower part of the Observations dialog. Now let’s display our simulated data so that we can see what is happening.


Figure 34. The GSSHA™ observations dialog.


11. Under base_calib change hide to be show.



The upper plot window now shows plots of the observed and predicted data. The lower plot window takes the difference between the two (the residuals) and plots it. Let’s look at how well our simulation matches the observed data.



12. Select the Calibration Analysis button.



The calibration analysis dialog computes a few objective functions for the set of residuals. Once you are done looking at the calibration analysis dialog:



13. Select OK, OK, OK to get back to the main WMS screen.



Your next goal is to create a few more projects so that we can compare data.



14. Select a parameter that you would like to modify and change it. (Try stream or overland roughness values to start with.)
15. After creating a new folder, save the project in the new folder with a different base file name than ‘base_calib.’
16. Run the model.



Once you have run another model you can go back to the same feature node as before to look at what changed in the output and also compare the new output data with the old and with the observed data set.

12   Groundwater

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA Version 3.0b and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Groundwater folder.
3. Select the EauGalleGSSHA.prj file and select Open.

Your watershed should look similar to the one shown in the image below. This is a subbasin of the Eau Galle watershed in Wisconsin.

Figure 35. Eau Galle Watershed.

GSSHA™ Model Setup

Hydrologic Modeling Wizard

1. At the bottom of the WMS window, click on the Hydrologic Modeling Wizard icon to open the Modeling Wizard.
2. Click on Select Model in the Wizard Task Bar on the left.
3. Select GSSHA for the desired model, but DO NOT click on the Initialize Model Data button.
4. Click on Define Land Use and Soil Data in the Wizard Task Bar on the left.
5. In the Define Land Use and Soil Data window, click the file browse button next to Add shapefile and open the file labeled EauGalleLU.shp. Make sure the Type is set to Land Use
6. Do the same for the soil type data and open the file labeled EauGalleST.shp. Make sure the Type is set to Soil Type
7. Click the Create Coverages button to create coverages from the land use and soil type data.
8. Click Next, Next, and Finish to create the Land Use coverage
9. Click Next, Next, and Finish to create the Soil Type Coverage
10. Click Next in the Hydrologic Modeling Wizard
11. In the Hydrologic Computations frame, click the Compute Index Mapping Tables button.



To model groundwater in GSSHA™ we will use 3 index maps. A soil type index map, a land use index map, and a combined soil type and land use index map. We will create these index maps from inside the wizard.



12. In the GSSHA™ Maps dialog, make sure the input coverage says Land Use and the coverage attribute says Id.
13. Change the Index map name to LU
14. Click the Coverages->Index Map button. You should see a land use index map appear in the WMS canvas window.
15. Now change the input coverage to Soil Type and the coverage attribute to Texture
16. Change the Index map name to ST
17. Click the Coverages->Index Map button. You should see a soil type index map appear in the WMS canvas window
18. Change Input coverage (1) back to Land Use and set the Coverage attribute to Id
19. Toggle on the option for Input coverage (2) and select the Soil Type coverage. Change the Coverage attribute to Texture.
20. Change the Index map name to Combined and click the Coverages->Index Map button. You should see a new index map appear in the WMS canvas window.
21. Click Done on the GSSHA™ Maps dialog

GSSHA™ Mapping Tables

1. In the GSSHA™ Map Table Editor, click on the Roughness tab
2. Set the index map to be LU and click Generate IDs
3. Set the Row Crops roughness to be 0.24, the Grass roughness to be 0.165, and the Forest roughness to be 0.235.
4. Click on the Interception tab.
5. Click Yes to turn the interception option on in the job control
6. Set the index map to be LU and click Generate IDs
7. Fill in the Interception spreadsheet with values from the following table:



Table 11. Values for Eau Galle Interception Row Crops Grass Forest Storage capacity (mm) 1.143 1.0 0.0423 Interception coeff (mm/hr) 0.045 0.027 0.18



8. Click on the Retention tab.
9. Click Yes to turn the retention option on in the job control
10. Set the index map to be LU and click Generate IDs
11. Leave the retention values at 0 for all three land uses
12. Click on the Evapotranspiration tab.
13. Click Yes to turn the evapotranspiration option on in the job control
14. In the GSSHA™ Job Control window, change the Evapotranspiration type to Penman method
15. Toggle on the option for Seasonal resist. and click OK
16. Set the index map to be LU and click Generate IDs
17. Fill in the Evapotranspiration spreadsheet with values from the following table:



Table 12. Values for Eau Galle Evapotranspiration Row Crops Grass Forest Land-surface albedo 0.2 0.2 0.2 Vegetation Height (m) 0.5 0.25 10.0 Vegetation Radiation Coeff 0.5 0.30 0.15 Canopy stomatal resistance (s/m) 45.0 100.0 120.0



18. Click on the Infiltration tab.
19. Click Yes to turn the infiltration option on in the job control
20. In the GSSHA™ Job Control window, change the Infiltration type to Green & Ampt with soil moisture redistribution and click OK.
21. Set the index map to be Combined and click Generate IDs
22. Fill in the Infiltration spreadsheet with values from the following table:



Table 13. Values for Eau Galle Infiltration Silt loam Silt loam Loam Loam Coarse sand Silt loam Loam Coarse sand Land ID #21 Row Crops Land ID #33 Grass Land ID #21 Row Crops Land ID #33 Grass Land ID #21 Row Crops Land ID #43 Forest Land ID #43 Forest Land ID #33 Grass Hydraulic Conductivity (cm/hr) 0.048342 0.156576 0.606576 1.09 0.2001 0.156576 0.606576 12.0 Capillary head (cm) 8.34 16.68 8.89 11.01 4.95 16.68 8.89 4.95 Porosity (m^3/m^3) 0.501 0.501 0.463 0.453 0.437 0.501 0.463 0.437 Pore Distribution index (cm/cm) 0.234 0.234 0.252 0.378 0.234 0.234 0.252 0.694 Residual saturation (m^3/m^3) 0.015 0.015 0.027 0.041 0.02 0.015 0.027 0.02 Field capacity (m^3/m^3) 0.33 0.33 0.27 0.207 0.12 0.33 0.27 0.091 Wilting Point (m^3/m^3) 0.12 0.12 0.12 0.12 0.12 0.12 0.12 0.12



23. Click on the Initial Moisture tab
24. Set the index map to be ST and click Generate IDs
25. Set the Coarse sand initial moisture to be 0.371, the Loam initial moisture to be 0.393, and the Silt loam initial moisture to be 0.42585.
26. Click Done to close the GSSHA™ Map Table Editor

Creating Groundwater Datasets

To add groundwater to the GSSHA™ model, we need to create five more datasets: a porosity map, a hydraulic conductivity map, an aquifer bottom map, a water table elevation map, and a boundary condition map. We'll set up the continuous maps outside of the Hydrologic Modeling Wizard.

Hydraulic Conductivity and Porosity

1. Click Close to close the Hydrologic Modeling Wizard.
2. In the 2D Grid Module select GSSHA™ | Maps...
3. Click on the tab labeled Continuous - Grid
4. Click on the Data Calculator... button
5. In the Expression field, enter 11.197
6. In the Result field, type HK, for hydraulic conductivity
7. Click the Compute button to create the continuous hydraulic conductivity map.
8. In the Expression field, enter 0.4
9. In the Result field, type Porosity
10. Click the Compute button to create the continuous porosity map.
11. Click Done to close the Data Calculator
12. Click Done to close the GSSHA™ Maps dialog

Aquifer Bottom

We will create the aquifer bottom map and the water table elevation map from x,y,z points that we have stored in a comma separated file.



1. In the WMS window, select File | Open
2. Open the file named aquifer_bot_elevs.csv
3. In the File Import Wizard, change the starting import row to 2
4. Make sure the Comma delimeter is toggled on and click Next>
5. Make sure the WMS data type is set to 2D Scatter Points
6. Make sure the first column is mapped to X, the second column to Y, and the third column to Data set
7. Click Finish to import the dataset as a 2D Scatter Point dataset



A new scatter point dataset named aquifer_bot_elevs should appear in the Project Explorer.




Figure 36. Aquifer Bottom Scatter Point Dataset


8. Right click on the aquifer_bot_elevs scatter set and choose Interpolate->...To Grid
9. Change the interpolated data set name to Aq_Bottom. DO NOT toggle on the option to Map elevations.
10. Click OK to create a grid from the aquifer bottom scatter points



You should now see a new continuous map named Aq_Bottom among the other continuous datasets.

Water Table Elevation

1. In the WMS window, select File | Open
2. Open the file named water_table_elevs.csv
3. In the File Import Wizard, change the starting import row to 2
4. Make sure the Comma delimeter is toggled on and click Next>
5. Make sure the WMS data type is set to 2D Scatter Points
6. Make sure the first column is mapped to X, the second column to Y, and the third column to Data set
7. Click Finish to import the dataset as a 2D Scatter Point dataset



A new scatter point dataset named water_table_elevs should appear in the Project Explorer.




Figure 37. Water Table Elevation Scatter Point Dataset


8. Right click on the water_table_elevs scatter set and choose Interpolate->...To Grid
9. Change the interpolated data set name to WTE. DO NOT toggle on the option to Map elevations.
10. Click OK to create a grid from the water table scatter points



You should now see a new continuous map named WTE among the other continuous datasets. Now we need to associate the new datasets with the Eau Galle GSSHA™ model.



11. Right click on the Continuous Maps folder underneath the EauGalleGSSHA folder in the 2D Grid Data section of the Project Explorer.
12. Select Assign->Aq_Bottom
13. Right click on the Continuous Maps folder again and select Assign->WTE



There should now be 5 continuous maps associated with the Eau Galle GSSHA™ model.

Groundwater Boundary Condition

1. Turn off the Scatter Point datasets in the Project Explorer
2. Click on the GSSHA™ coverage in the Project Explorer to make it the active coverage
3. Choose the Select Feature Line Branch tool and double click on the most downstream stream arc
4. In the All row (highlighted in yellow) of the Properties spreadsheet, change the Type to Trapezoidal Channel



For this example, we will assume the stream geometry is the same everywhere in the model.



5. Still in the All row, enter a Manning's n of 0.119, a Depth of 0.5, a Bottom Width of 1.0, and a Side slope of 4.2
6. For the Groundwater BC, select Flux River. This will assign a flux river boundary condition to all the stream cells that underlie the stream arcs.
7. Click OK to close the Properties dialog
8. Switch to the 2D Grid Module
9. With the 2D Grid Module selected, select GSSHA™ | Job Control...
10. Change the Channel routing computation scheme to Diffusive wave
11. Toggle on the Groundwater option and click Edit parameter...



When toggling on the Groundwater option, a groundwater boundary index map named Gw boundary is created automatically in the Project Explorer. Notice the stream cells representing the flux river boundary condition on the Gw boundary grid. Also, a no-flow boundary condition is assumed to exist around the perimeter of the watershed.

Groundwater Job Control

1. In the GSSHA Groundwater dialog, set the Aquifer... Data Set to Aq_Bottom, the Water... Data Set to WTE, the Hydra... Data Set to HK, and the Porosity Data Set to Porosity.
2. Set the Time Step to be 600
3. Make sure the LSOR direction is set to Vertical
4. Make sure the LSOR convergence is 0.00001
5. Make sure the Relaxation coefficient is 1.2
6. Make sure the Leakage rate is set to 0.0
7. Click OK to close the GSSHA Groundwater dialog
8. In the GSSHA™ Job Control window, make sure the Overland flow Computation method is set to ADE
9. Click OK to close the GSSHA™ Job Control Parameters dialog

Precipitation

Groundwater is most often used for long-term simulations. To finish setting up a long-term GSSHA™ simulation, we need to enter long-term precipitation data.

1. With the 2D Grid Module selected, select GSSHA™ | Precipitation
2. In the Rainfall event(s) combo box, change the type to Gage.
3. Click the Import Gage File... button
4. Open the file named rain_combine_events_may15.gag
5. Change the Multi-gage interpolation method to Thiessen polygons



You'll notice many storm events are now shown in the Project Explorer.



6. Click OK to close the GSSHA™ Precipitation dialog
7. Select GSSHA™ | Job Control...
8. Toggle on the option for Long term simulation and click Edit parameter...
9. Set the Latitude to be 44.81
10. Set the Longitude to be 267.83
11. Set the GMT at -6.0
12. Enter a Minimum event discharge of 0.1
13. Enter a Soil moisture depth of 0.25
14. Click the Browse button next to HMET Data File
15. Open the file named Wisconsin_HMet_formatted2002_may15.txt
16. Change the HMET Data Format to WES
17. Click OK to close the Continuous Simulation dialog
18. Click OK to close the GSSHA™ Job Control Parameters dialog

Saving and Running the GSSHA™ Model

We are now ready to save and run the GSSHA™ model.

1. With the 2D Grid Module selected, select GSSHA™ | Save Project File
2. Save the GSSHA™ Project as EauGalleGSSHARun1 and click Save
3. Select GSSHA™ | Run GSSHA™
4. Toggle off the option to Suppress screen printing and click OK

The model should take about an hour and a half to two hours to run, depending on the speed of your computer. If you would like to view the solution without waiting for the model to run to completion, click the Abort button, select GSSHA | Read Solution and open the solution for EauGalleGSSHASed.prj in the Sediment folder.

Viewing GSSHA™ Model Results

1. Once the model has finished running, make sure the Read solution on exit option is toggled on and click Close. It may take some time to read in the solution.
2. Once the solution file has been read in, choose the Select hydrograph tool and double click on the hydrograph icon near the watershed outlet
3. This will open up an outflow hydrograph plot which you can copy to the clipboard or export to Excel (Figure 38)




Figure 38. Eau Galle Groundwater Model Outflow Hydrograph.


4. You may also wish to explore the summary file or view depth contours
5. Though it will take some time, you may also wish to create a movie file of your rendered depth contours
6. You can tell GSSHA™ to output more than just the depth dataset. If you wish to view groundwater specific datasets such as infiltration rate or groundwater elevations, change the Output Control settings in the GSSHA™ Job Control dialog and rerun the model.

This concludes the GSSHA™ Groundwater Tutorial.

13   Sediment

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA™ Version 4.0 and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

This tutorial builds on the the previous tutorial, Tutorial 12: Groundwater.

If you are starting at this tutorial,

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Sediments folder.
3. Select the EauGalleGSSHASed.prj file and select Open.

This is a GSSHA™ model of the Eight Mile Run basin in the Eau Galle River watershed in Wisconsin. This is a long-term model with groundwater parameters included.

Adding Soil Erosion

1. In the 2D Grid Module select GSSHA™ | Job Control...
2. Click on the Soil erosion box

Adding Sediment

1. Click the Edit parameter... button next to the soil erosion spreadsheet option
2. Make sure the Transport capacity is set to Kilinc-Richardson
3. Click the Add button three times to add three Sediments
4. Fill in the Sediments spreadsheet with values from the following table:



Table 15. Values for Eau Galle Sediments. ID# Description Sp. Grv. Pt. Diam Sorb Affinity Base Output Filename (*.gflx, *.gdep, *.lflx, *ldep) 1 Sand 2.65 0.25 0.1 sand 2 Silt 2.65 0.16 0.3 silt 3 Clay 2.65 0.001 0.6 clay



5. Click OK to close the Overland soil erosion dialog
6. Click the Edit Parameters... button in the Channel routing computation scheme portion of the Job Control dialog (top right corner).
7. Make sure the Sediment porosity is set to 0.4, the Water temperature at 20.0 deg C, and the Sand size at 0.25 mm.
8. Leave all other values at their defaults and click OK to close the GSSHA™ Channel Routing Parameters dialog
9. Click OK to close the GSSHA™ Job Control dialog

Specifying Soil Erosion Parameters

1. In the 2D Grid Module select GSSHA™ | Map Tables...
2. Click on the Soil Erosion tab.
3. In the Using index map combo box, select the Combined index map
4. Click Generate IDs
5. Fill in the spreadsheet with values from the following table:



Table 14. Values for Eau Galle Soil Erosion Description 1 Silt loam Silt loam Loam Loam Coarse sand Silt loam Loam Coarse sand Description 2 Land ID #21 Row Crops Land ID #33 Grass Land ID #21 Row Crops Land ID #33 Grass Land ID #21 Row Crops Land ID #43 Forest Land ID #43 Forest Land ID #33 Grass Transport coefficient 0.285 0.285 0.285 0.285 0.285 0.285 0.285 0.285 Transport index 1.30 1.30 1.30 1.30 1.30 1.30 1.30 1.30 Crit. transport capacity 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 Rain splash coeff 1200.0 1200.0 1200.0 1200.0 1200.0 1200.0 1200.0 1200.0 Runoff detachment coeff 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 Runoff detachment index 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Runoff detachment crit. shear 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Erodibility coeff 0.0688 0.0088 0.034 0.0048 0.005 0.0088 0.0068 0.0005 Sand 0.2 0.2 0.5 0.5 0.9 0.2 0.5 0.9 Silt 0.7 0.7 0.4 0.4 0.1 0.7 0.4 0.1 Clay 0.1 0.1 0.1 0.1 0.0 0.1 0.1 0.0



6. Click Done to close the GSSHA™ Map Table Editor

Saving and Running the Model

1. In the 2D Grid Module select GSSHA™ | Save Project File...
2. Change the project name to EauGalleGSSHASed1.prj and click Save
3. In the 2D Grid Module select GSSHA™ | Run GSSHA™...
4. Toggle on the option to suppress screen printing and click OK
5. Once the model is done running, make sure Read solution on exit is toggled on and click Close.

Post-Processing

1. In the Project Explorer, right-click on the Outlet Sedograph, located below the GSSHA™ solution folder (the folder with the letter "S" on it)
2. Select View Graph...
3. The plot window should show the sedograph, which should look similar to Figure 39.




Figure 39. Eau Galle Groundwater/Sediment Model Outflow Sedograph.


4. Close the sedograph plot.



If you wish to view more sediment related output, go into the GSSHA™ Job Control, click on Output Control, and toggle on any datasets you would like GSSHA™ to output. Then save your project and run it again.

This concludes the GSSHA™ Sediment tutorial.

14   Wetlands

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA™ Version 4.0 and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Run the Base Model

If you are starting at this tutorial:

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Judy's_Branch_tutorial\Finished_tutorial\streams_xsec directory and open the file named streams_xsec.prj.
3. In the 2D Grid Module select GSSHA™ | Save Project File.
4. Save the file as NoWetlands.prj
5. Select GSSHA™ | Run GSSHA™
6. When GSSHA™ finishes running, make sure the option to Read the solution is toggled on and click Close
7. With the Select Hydrograph tool selected, double click on the hydrograph icon near the outlet
8. The runoff hydrograph should look similar to Figure 40.




Figure 40. Judy's Branch Base Model (No Wetlands).

Adding Wetlands

1. Make sure the GSSHA™ coverage is the active coverage in the Project Explorer
2. Choose the Create Feature Arc tool
3. Using the Create Feature Arc tool , create two wetland polygons in the upstream portion of the watershed similar to those shown in Figure 41.




Figure 41. Wetland Polygons.


4. Choose the Select Feature Arc tool
5. Hold down the shift key and select the two wetland polygons you just created
6. Select Feature Objects | Build Polygons
7. Choose the Select Feature Polygons tool
8. Double click on one of the wetland polygons
9. Change the Polygon type to Wetland
10. Enter an Initial storage depth of 0.0 mm, a Retention depth of 1000 mm, a Retention depth hydraulic conductivity of 1 m/day, a Vegetation height of 500 mm, a Vegetation height hydraulic conductivity of 10 m/day, and an Inundated Manning's n-value of 0.1.
11. Click OK to close the GSSHA™ Polygon Attributes dialog
12. Repeat for the other wetland polygon

Save and Run the Wetlands Model

1. In the 2D Grid Module select GSSHA™ | Save Project File.
2. Save the file as Wetlands.prj
3. Select GSSHA™ | Run GSSHA™.
4. When GSSHA™ is done running, make sure the option to Read solution on exit is toggled on and click Close.
5. With the Select Hydrograph tool selected, double click on the hydrograph icon near the watershed outlet.
6. Notice the lower peak flow when wetlands are added. Your hydrograph should look similar to Figure 42.




Figure 42. Runoff Hydrograph Comparison with and without Wetlands.

This concludes the GSSHA™ wetlands tutorial.

15   Overland Flow Boundary Condition

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA Version 5.0 and later
  

Disclaimer: GSSHA tutorial exercises do not necessarily represent real world conditions

Overview

A report can be downloaded here that describes a model used to simulate the water depths on Galveston Island from Hurricane Ike. The results from this model were compared to the measured water depths during the hurricane.

The raw data used for this tutorial can be downloaded here.

Overland Flow Tutorial and Steps

Extent of boundary conditions in Galveston Island GSSHA Model

1. Open the hydrologic modeling wizard, use the UTM Zone 15 (metric) coordinate system, and define the model boundary.
2. Open the DEM (36991726.hdr), the land use data (Houston.shp), and the image (galveston2m.tstopo.web.jpg) (optional).
3. Run Topaz to compute the flow direction and flow accumulation grids.
4. Delineate the watershed with the outlet located between Galveston Sewage Disposal Plant and Pier 41 in the west shore of the island as shown in the image. Use a stream threshold value of 0.05 square miles. The preliminary watershed area should be approximately 1.21 square miles.
5. Starting from the outlet point, create an arc that follows the DEM contour lines to extend boundary of watershed. Once you have outlined your new watershed extent, define your basin, and then convert from basin to polygon. The new watershed area should be approximately 13.07 square miles.
6. Select GSSHA as your model and initialize the model data.
7. You do not need to set stream arc attributes as you will not use the stream in your model.
8. Create a 2D grid with a resolution of 60 m.
9. Run a 2-day simulation, starting at 6 PM on 9/12/2008 and ending at 6 PM on 9/14/2008.
10. Define your land use coverage by selecting the Create Coverages button in the Define Land Use and Soil Data step of the wizard.
11. Create land use index maps. Use the land use index map for your roughness values.
12. Read the gssha.cmt file to get initial values for overland Manning’s roughness. In your job control, turn off the Green and Ampt method of infiltration, select no routing, and set your output to write a hydrograph value every 10 minutes and to write in English units. Turn on Channel depth and Channel flow in the Link/Node data set output.
13. Set the precipitation method to Uniform and enter an intensity of 10.5 mm/hr for 24 hours.
14. Create a node in the start point and end point of your east boundary arc as shown in the image. Set your arc attributes to variable depth and enter the Galveston Pleasure Pier storm surge time series. GSSHA automatically named the time series as ts_26.
15. Create a node in the start point and end point of your west boundary arc as shown in the image. Include a node in the middle where the watershed outlet is located. Set your arc attributes to variable depth and enter the Galveston Pier 21 storm surge time series. GSSHA automatically named the time series as ts_27.
16. Using the topo map as a guide, create an embankment arc where the levee surrounding Old Fort San Jacinto is located (north of Galveston Island). In the embankment dialog box, set embankment height to 6 m.
17. Using the topo map as a guide, create an embankment arc where the seawall goes inland (behind Stewart Beach Park in the northeast section of the island). In the embankment dialog box, set embankment height to 6 m. Make sure that the two embankments don’t overlap.
18. Save your model.
19. Select the option to clean up your model and make sure there are no errors in your model.
20. Run the GSSHA simulation (using GSSHA 5.0). Calibrate your inundation depths to the observed depths using the values shown in this report or using some other calibration method.
21. Create an animation filmloop using this model and open the KMZ animation file in Google Earth.

16   Simple Constituent Transport

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA Version 5.0 and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Two types of reactive constituent transport are available in GSSHA. As explained in the GSSHA wiki, constituents can be simulated as simple first order reactants. The nutrient cycle can also be simulated with the Nutrient Simulation Model (NSM). In either case, the overall simulation methods within the GSSHA model are the same. Only the rates of mass absorption and decay are different. It is then possible to simulate nutrients as simple constituents, as well as simulating them with the full nutrient cycle. Use of first order constituents requires that the user have explicit information about the contaminants being simulated as the user must supply all the reaction rates for the model. On the other hand, when using NSM many different reactions occur and most of the reaction rates are calculated by NSM. There is no limit as to the number of simple constituents that can be simulated at one time. In this tutorial, two contaminants will be simulated.

Open the Base Model

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Judy's_Branch_tutorial/Contaminant_Transport directory and open the file named Contaminants.prj.
3. In the 2D Grid Module select GSSHA™ | Save Project File.
4. Browse to the Judy's_Branch_tutorial/Contaminant_Transport/Personals directory and save the file as Contaminant_Transport.prj.

This base model has already been set as a long term simulation model with precipitation data and meteorological data for one week. If you have questions on how to set a long term simulation model, please refer to the Long Term Simulations Tutorial.

Adding Contaminants

Constituent transport can be simulated on the overland flow plane, in the channel network including reservoirs, and in the soil column. These parameters are added in different dialog boxes in GSSHA as shown in the steps below.

1. Make sure that your project has 12 coverages,9 of which should be rainfall events. GSSHA™ should be the active coverage in the Project Explorer as shown in Figure 1 below.
2. Select the 2D Grid Module if not already selected. Go to GSSHA™ | Job Control.
3. In the dialog box that opens, click on the box beside Contaminant Transport to select this option. Make sure that Long Term Simulation is also selected. See Figure 2.
4. Click on the Edit parameter button for Contaminant Transport. In the dialog box that opens, click on the add button to add two contaminants and enter the information found in Table 1. Click OK.

Figure 1

Figure 2

The base output file column specifies the location of the output files that will be generated for each contaminant. Make sure the location for contaminant1 and contaminant2 is as follows:

\Judy's_Branch_tutorial\Contaminant_Transport\Personals\Contaminant1

\Judy's_Branch_tutorial\Contaminant_Transport\Personals\Contaminant2

This is the first step in parameter input. This information will help populate the mapping table with the number of contaminants that will be simulated. Notice that in the index map column you had the option of choosing between Uniform, Land Use, Soil Type and Combined Index Maps. The index map you use will depend on the nature of your model. The Uniform Index map can be used just to set up your model and make sure it is working as it simplifies the setup, but it does not necessarily represent real conditions. The use of the other three Index Maps will depend on the nature of the contaminants you are simulating. This requires that you know your project really well. In this tutorial we will use the Land Use Index Map. We will assume that a certain area of our watershed is contaminated by either point or non-point sources. This could be a landfill, or areas that receive runoff and/or leachate from agricultural activities, residential areas or from mining and logging operations.

Before entering the needed parameters in the mapping table we will define the contaminant conditions for the channel network.

1. In the Job control Dialog box that is still open, make sure that Diffusive Wave is selected. Click on Edit Parameters. A dialog box will show up as shown on Figure 3.
   
   

   

   Figure 3

2. Select Compute Contaminant Transport and enter the following values:

   decay coefficient: 1.0

   dispersion coefficient: 1.0

   Initial Concentration: 0.0

3. Click OK. This will define the conditions in the channel network.
4. Click OK to close the job control dialog box.

With the 2D grid as your active module, go to GSSHA™ | Map Tables. Values for Roughness, Evapotranspiration, Infiltration and Initial Moisture should already be defined. We will now fill in the values for Contaminants.

1. Click on the Contaminants Tab. From the Index Map Drop down Menu select “Land Use”.
2. From the Contaminant Drop down Menu select each contaminant and click Generate IDs. You will have five columns of values for each contaminant. Input the values from Table 2 and Table 3 respectively:

Table2

Parameters	Contaminant 1
	LU 11	LU 14	LU 16	LU 21	LU 41
Dispersion (m2/s)	0	0	0	0	0
Decay (d-1)	1	1	1	1	1
Uptake (m/day)	1	1	1	1	1
Mass loading (kg/cell)	100	0	0	0	0
Groundwater concentration (mg/L)	1	0	0	0	0
Initial Concentration (mg/L)	0	0	0	0	0
Soil water distribution coefficient (L/kg)	0.5	0.5	0.5	0.5	0.5
Max concentration/ solubility-Cmax (mg/L)	100000	100000	100000	100000	100000




Table 3

Parameters	Contaminant 2
	LU 11	LU 14	LU 16	LU 21	LU 41
Dispersion (m2/s)	0.5	0.5	0.5	0.5	0.5
Decay (d-1)	0.8	0.8	0.8	0.8	0.8
Uptake (m/day)	1.5	1.5	1.5	1.5	1.5
Mass loading (kg/cell)	200	0	0	0	0
Groundwater concentration (mg/L)	0	0	0	0	0
Initial Concentration (mg/L)	0	0	0	0	0
Soil water distribution coefficient (L/kg)	0.4	0.4	0.4	0.4	0.4
Max concentration/ solubility-Cmax (mg/L)	100000	100000	100000	100000	100000



3. Click OK

Populating the mapping tables in this way is telling WMS that only the Land Use 11 has contaminant loading. The rest of the watershed has been assigned values of zero. Let’s take a look at the parameters required to simulate contaminant transport. Dispersion refers to the mixing that occurs because the porous media forces some solute molecules to move faster than others while following a tortuous path through pores of different sizes ⁽¹⁾. It is caused by variation in velocities and it can be vertical, lateral and longitudinal. Typical values of dispersion coefficient (m²/sec) can range from 10^-3 to 10^-1 (vertical), 10^-2 to 10⁰ (lateral) and 10^-1 to 10⁴ (longitudinal). ⁽²⁾

The Decay coefficient (K_d) represents the production or decay of solute concentration within the porous medium. It is a rate constant that represents increasing concentration when it is negative in value and decreasing concentration when it is positive. ⁽³⁾ Examples of values for some constituents are found in Table 4.

We understand uptake (K_u) to be the incorporation or absorption of a constituent such as a nutrient by a medium (or a tissue if when referring to organisms), and its permanent or temporary retention. Examples of uptake coefficient values are found in Table 5.

The mass loading (kg/cell) refers to the amount of contaminant present in the overland cell. If we are simulating contaminant transport within the soil column, then the mass loading refers to the mg of contaminant per kg of soil.

The initial concentration values asked for in the mapping table refer to the concentration of constituents in a water surface, or in other words, the hot start concentration.

The soil water distribution coefficient (K_d) also known as partition coefficient is a direct measure of the partitioning of a contaminant between the solid and aqueous phases. (9) Table 6 has partition coefficients for lead in different media combinations, obtained from the EPA site.

As you can see, modeling first order constituents require that you have a thorough knowledge of your contaminant and modeling area as you are required to input the coefficients previously described.

Our model has all the required inputs to simulate contaminants. We are ready to run the model.

Save and Run the Contaminants Model

1. In the 2D Grid Module select GSSHA™ | Save Project File.
2. Save the file as Contaminant_Transport.prj
3. When prompted to replace the existing file, click yes.
4. Select GSSHA™ | Run GSSHA™.
5. When GSSHA™ is done running, make sure the option to Read solution on exit is toggled on and click Close.

View Results

There are several different outputs generated when running the model. In the outlet location, you should get two constituent graph solutions, one for Constituent Mass and one for Constituent Concentration.

1. In the Project Explorer, right-click on the Outlet Constituent Mass graph, located below the GSSHA™ solution folder (the folder with the letter "S" on it)
2. Select View Graph. You have the option of selecting the contaminant you want to view. The plot window should show a graph similar to the one in Figure 4.
3. Close the contaminant plot.






Figure 4




4. You can follow the same steps for Constituent Concentration graph. A plot for the concentration of both contaminants is shown in Figure 5.






Figure 5

To view overland contaminant mass and concentration, do the following:

1. In the 2D Grid module select Display | Display Options
2. Turn on the 2D Grid Contours.
3. Select OK.
4. In the data tree, right-click on mass_01 under the solution folder.
5. Select Contour Options.
6. Under Contour Method select 'Color Fill.'
7. Click on Color Ramp. A dialog box as shown in Figure 6 will appear. Click the Reverse button.
8. Select OK.
9. In the mass_01 Contour options dialog, the number of contours should be defaulted to 20. Reduce this number to 10.






Figure 6




10. In the Contour Method drop down menu that is defaulted as ‘use Color Ramp’, select ‘Specify each color’.
11. You will note that the colors have now a drop down menu. Change your first color from blue to white. Leave the rest as they are. See Figure 7
12. Click OK to exit the dialog box.






Figure 7


A set of time steps appear in the right pane of your WMS window as you selected mass_01. Click around on a few of them between 7:00-10:00 a.m. on 08/24/2001. It would be helpful if we knew what the colors represented.

13. Right-click on mass_01 in the data tree.
14. Select Contour Options.
15. Turn on the legend.
16. Click OK.

Your mass overland display for contaminant 1 (08/24/01 at 9:45 am) should look something like this:






Figure 8




17. You can follow steps from 4-15 if you want to visualize mass_02, conc_01 or conc_02 as well.

In order to visualize mass and contaminant concentrations along the stream network, we need to turn on the contours for the 2D Scatter Data.

1. In the project explorer, right click the Link/node icon. Select the Display Options dialog.
2. Turn on the contours for the 2D Scatter Data.
3. Select a radius and Z Magnification (try a radius of 4 and a Z magnification of 50). If the lines are too big, you might need to decrease the Z magnification.
4. Click OK.
5. Select either the Contaminant mass or the Contaminant conc. data set in the 2D Scatter Data folder in the data tree.
6. Select a time step other than the first one in the Properties window, such as 08/24/2001 between 7:00-10:00 am.
7. If you rotate into 3D mode , or change from plan view to perspective view , you will see the lines representing stream mass. In the properties folder you will see the time steps. As you select individual time steps the data for that time step both the 2D grid data and the 2D scatter data will be contoured.

Your display for contaminant mass on the stream network (08/24/2001 9:45 am) should look something like this:

Figure 9

Even when behavior of contaminants in the soil column is not graphically displayed in WMS, we can open the summary file and get information on this and the rest of the processes simulated.

1. Double-click on Summary File under the solution folder.
2. If WMS asks for your editor just click OK.
3. Look through the summary file. Notice the kinetics of overland, stream and soil column contaminant transport. It is also good to check things like mass balance and the volume remaining on the surface.
4. When you are done you can close the window.

This concludes the GSSHA™ constituent transport tutorial.

References

(1) http://ocw.mit.edu/NR/rdonlyres/Civil-and-Environmental-Engineering/1-72Fall-2005/7003EAB8-3DE1-4A52-96B3-18E503FD55CE/0/1_72_lecture_11.pdf

(2) Ecosystems Research Division. WASP7 Course. Environmental Protection Agency. http://www.epa.gov/athens/wwqtsc/courses/wasp7/

(3) Modeling the Environmental Fate of Microorganisms. Christon J. Hurst. 1991 http://books.google.com/books?id=TMgoX86EIZIC&pg=PA30&lpg=PA30&dq=contaminant+decay+coefficient+K&source=bl&ots=3KrR2ex-JY&sig=akvyOWf6ZH1JqonIaulACZQpFrs&hl=en&ei=oPVcSsaZEILusgONru2lCg&sa=X&oi=book_result&ct=result&resnum=1

(4) Experimental Determination of Anammox Decay Coefficient. D. Scaglione et.al. Journal of Chemical Technology and Biotechnology. Vol 84. Issue 8. 1250-1254. http://www3.interscience.wiley.com/journal/122267762/abstract

(5) Bioremediation and Natural Attenuation. Pedro J. J. Alvarez, Walter Arthur Illman. 2005 http://books.google.com/books?id=fSUtC8luIp0C&pg=PA196&lpg=PA196&dq=decay+coefficients&source=bl&ots=yRW20vQ_UW&sig=3GsPXKt2r9Vb2h_U7fV_PIQfxSU&hl=en&ei=kjJWSu2KDpDWtgOOqK3PDg&sa=X&oi=book_result&ct=result&resnum=6

(6) Water Resources and Natural Control Processes. Lawrence K. Wang, Norman C. Pereira. 1987. http://books.google.com/books?id=lR2DeuTrTsMC&pg=PA62&lpg=PA62&dq=simple+and+reactive+constituents&source=bl&ots=aGp9KEYkJA&sig=LVZEF_OjSao0jkpjKCs0BhuX1K4&hl=en&ei=bC9WSvbwIYrasQOeqKX0AQ&sa=X&oi=book_result&ct=result&resnum=6

(7) Interpretation of Uptake Coefficient Data Obtained with Flow Tubes. E. James Davis J. Phys. Chem. A, 2008, 112 (9), pp 1922–1932. February 12, 2008 http://pubs.acs.org/doi/abs/10.1021/jp074939j

(8) The Uptake Coefficient of I2 on Various Aqueous Surfaces. Takami Akinori et.al. Journal of Atmospheric Chemistry. ISSN 0167-7764. 2001, vol. 39, no2, pp. 139-153. http://cat.inist.fr/?aModele=afficheN&cpsidt=1095928

(9) http://www.epa.gov/rpdweb00/docs/kdreport/vol2/402-r-99-004b_appf.pdf

(10) http://www.epa.gov/rpdweb00/docs/kdreport/vol2/402-r-99-004b_appf.pdf

17   Nutrients

This tutorial is compatible with:

• WMS Version 8.2 and later
• GSSHA Version 5.0 and later
  
  

Disclaimer: GSSHA tutorial exercises do not represent real world conditions

Two types of reactive constituent transport are available in GSSHA. As explained in the GSSHA wiki, constituents can be simulated as simple first order reactants. The nutrient cycle can also be simulated with the Nutrient Sub-Model (NSM). In either case, the overall simulation methods within the GSSHA model are the same. Only the rates of mass absorption and decay are different. It is then possible to simulate nutrients as simple constituents, as well as simulating them with the full nutrient cycle.

Modeling of nutrients in NSM consists of three distinct parts. The first part deals with simulating the nitrogen (N) and the phosphorus (P) cycle in the soil, whereas the second part focuses on the transformation and loading of N and P species in the overland flow. The third part simulates the most important processes for N and P cycle, dissolved oxygen and phytoplankton kinetics and can be used as a basic in-stream water quality model.

Open the Base Model

1. In the 2D Grid Module select GSSHA™ | Open Project File.
2. Browse to the Judy's_Branch_tutorial/NSM directory and open the file named nsm1.prj.
3. In the 2D Grid Module select GSSHA™ | Save Project File.
4. Browse to the Judy's_Branch_tutorial/NSM/Personals directory and save the file as nsm1.prj.

Setting up a GSSHA simulation with NSM constituents requires first a running hydrology model that includes simple constituents just to see that the model is transporting constituents appropriately. Once this is working, the NSM constituents can be set up. This base model has already been set as a long term simulation model with two simple constituents, as well as precipitation data and meteorological data for one week. If you have questions on how to set a long term simulation model or a simple constituent model, please refer to the the Long Term Simulations Tutorial and the Simple Constituent Transport Tutorial.

Adding NSM Constituents

1. Make sure that your project has 12 coverages, 9 of which should be rainfall events as shown in Figure 1 . GSSHA™ should be the active coverage in the Project Explorer.

Figure 1

Figure 2

1. Select the 2D Grid Module if not already selected. Go to GSSHA™ | Job Control.
2. In the dialog box that opens, click on the box beside Nutrients to select this option. Make sure that Long Term Simulation and Contaminant Transport are also selected. See Figure 2.
3. Click on the Edit parameter button for Nutrients. In the dialog box that opens, you can see four tabs: Point-Source, Non-Point Source, Other and Uniform Properties as shown in Figure 3. click on the Other tab.

Figure 3

In the Other tab you will see a list of parameters. Only temperature and channel pH have values assigned. The other parameters refer to rainfall concentrations for each constituent. In real life, we may or may not know the rainfall concentration of each constituent being simulated and in this case values of zero can be assigned. In addition, these concentrations may vary for each rainfall event as they are dependent on pollution at a given time. For the purpose of this tutorial, enter the following values:

Notice that contaminant 1 (1 mg/L) and contaminant 2 (0.5 mg/L) are included in this dialog box. The concentrations should be the same as the ones previously specified in the contaminant transport dialog box.

1. Click OK to close the nutrients dialog box.
2. Next to the Long Term Simulation check box, click on Edit parameters . In the dialog box that opens, toggle on the Use Soil Contaminant Transport and enter the following: Top Layer depth:1m, Mixing Layer Depth:0.5m
3. Make sure your soil moisture depth is set to 1.5m. Click OK to close the Continuous Simulation Dialog Box. Click ok to close the Job Control Dialog box.

The next step in setting an NSM Model is to create a Stream Index Map. This map is used to input aquatic kinetic constants for the stream network.

1. With the 2D grid as your active module, go to GSSHA™ | Maps.
2. In the dialog box that opens, select the Index-Stream Tab
3. Click the Add button and rename your index map as "Stream". See Figure 4.
4. Click Done.

Figure 4

1. With the 2D grid as your active module, go to GSSHA™ | Map Tables. Values for Roughness, Evapotranspiration, Infiltration, Initial Moisture and Contaminants should already be defined. We will now fill in the values for Nutrients.
2. Click on the Nutrients Tab. You will see three drop down menus, one for a grid map, one for a stream map and one for a map table as shown in Figure 5. From the Grid Map Drop down Menu select "Uniform". From the Use Stream Map select "Stream" and from Map table Select "Aquatic Kinetic Constants".

Figure 5

1. Click Generate IDs . You will have one column of values as we are using a Uniform Index Map. Notice that in the Use grid map drop down menu you had the option of choosing between Uniform, Land Use, Soil Type and Combined Index Maps. The index map you use will depend on the nature of your model. The Uniform Index map can be used to set up your model and make sure it is working as it simplifies the setup, but it does not necessarily represent real-world conditions.
2. WMS populates the column with default values and we will use those default values in this tutorial. Notice that the dispersion coefficients were assigned values of zero. Please enter the following values:

1. In the Map Table drop down menu there are 13 other options that require values. Select each one of the map table options, and generate IDs for each one using the maps indicated in Table 3.
2. Input the values found also in Table 3.

The last step before saving and running your model is specifying the output files you want to simulate and display in WMS.

1. In the 2D grid module, select GSSHA™ | Job Control
2. Click on Output Control.
3. In the Data Type Drop Down Menu, select Nutrients-Overland.
4. You will see a list of nutrients that can be simulated in the overland flow. Turn output on for all of the nutrients.
5. Scroll down the Link/Node Data sets options. You will see a list of nutrient output that can be turned on for nodes in the stream network. Select all of them starting from Stream Nitrite and ending with Stream dissolved oxygen. Your dialog box should look something like Figure 6.
6. Click OK to close the GSSHA Output Control dialog box. Click OK to close the GSSHA Job Control dialog box.

Figure 6

Save and Run the Contaminants Model

1. In the 2D Grid Module select GSSHA™ | Save Project File.
2. Save the file as nsm1.prj
3. When prompted to replace the existing file, click yes.
4. Select GSSHA™ | Run GSSHA™.
5. When GSSHA™ is done running, make sure the option to Read solution on exit is toggled on and click Close.

View Results

There are several different outputs generated when running the model. In the outlet location, you should get two constituent graph solutions, one for Constituent Mass and one for Constituent Concentration.

1. In the Project Explorer, right-click on the Outlet Constituent Mass graph, located below the GSSHA™ solution folder (the folder with the letter "S" on it)
2. Select View Graph. You have the option of selecting the constituents you want to view. For example, for nitrite and organic phosphorus, the graph should be similar to the one in Figure 7.
3. Close the constituent plot.
4. You can follow the same steps for Constituent Concentration graph. A plot for the concentration of ammonium and organic nitrogen is shown in Figure 8.

Figure 7

Figure 8

To view overland contaminant mass and concentration, do the following:

1. In the 2D Grid module select Display | Display Options
2. Turn on the 2D Grid Contours.
3. Select OK.
4. In the data tree, right-click on OV_no2_mass under the solution folder.
5. Select Contour Options.
6. Under Contour Method select 'Color Fill.'
7. Click on Color Ramp. A dialog box as shown in Figure 9 will appear. Click the Reverse button.
8. Select OK.
9. In the OV_no2_mass Contour options dialog, the number of contours should be defaulted to 20. Reduce this number to 10.
10. In the Contour Method drop down menu that is defaulted as ‘use Color Ramp’, select ‘Specify each color’.
11. You will note that the colors have now a drop down menu. Change your first color from blue to white. Leave the rest as they are. See Figure 10.
12. Click OK to exit the dialog box.

Figure 9

Figure 10

A set of time steps appear in the right pane of your WMS window as you selected OV_no2_mass. Click around on a few of them between 2:45am-11:00p.m. on 08/24/2001. It would be helpful if we knew what the colors represented.

1. Right-click on OV_no2_mass in the data tree.
2. Select Contour Options.
3. Turn on the legend.
4. Click OK.

Your mass overland display for OV_no2_mass (08/24/01 at 9:45 am) should look something like Figure 11.

Figure 11

1. You can follow steps from 4-16 if you want to visualize the rest of the constituents. Units of mass are in g/s and units of concentration are in mg/L.

In order to visualize mass and contaminant concentrations along the stream network, we need to turn on the contours for the 2D Scatter Data.

1. In the project explorer, right click the Link/node icon. Select the Display Options dialog.
2. Turn on the contours for the 2D Scatter Data.
3. Select a radius and Z Magnification (try a radius of 4 and a Z magnification of 50). If the lines are too big, you might need to decrease the Z magnification.
4. Click OK.
5. Select Dissolved P mass in the 2D Scatter Data folder in the data tree. Make sure that the Dissolved P mass is also selected for the overland plane (Under the Solution Folder in the Project Explorer).
6. Select a time step other than the first one in the Properties window, such as 08/24/2001 between 7:00-12:00 am.
7. If you rotate into 3D mode , or change from plan view to perspective view , you will see the lines representing stream mass. In the properties folder you will see the time steps. As you select individual time steps the data for that time step both the 2D grid data and the 2D scatter data will be contoured.

Your display for Dissolved P mass on the stream network (08/24/2001 9:45 am) should look something like Figure 12:

Figure 12

If you want more information on the project results we can open the summary file and get information on this and the rest of the processes simulated.

1. Double-click on Summary File under the solution folder.
2. If WMS asks for your editor just click OK.
3. Look through the summary file. Notice the kinetics of overland, stream and soil column constituent transport. It is also good to check things like mass balance and the volume remaining on the surface
4. When you are done you can close the window.

This concludes the GSSHA™ NSM tutorial.