Tutorials:14 Wetlands

From Gsshawiki

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.

GSSHA Tutorials

1   Initial Overland Flow Model Setup

2   Visualizing Overland Flow Results

3   Fixing Digital Dams

4   Using the Mapping Table and GIS Data

5   Stream Flow

6   Visualizing Stream Data

7   Break-point Cross Sections

8   Infiltration

9   Long-Term Simulations

10   Using Microsoft® Excel® to format GSSHA™ data

11   Manual Calibration

12   Groundwater

13   Sediment

14   Wetlands

15   Overland Flow Boundary Conditions

16   Simple Constituent Transport

17   Nutrients