InfoSWMM 2D Exercises

Chapter 12 Exercises


The exercises in this chapter will give you practice in exploring some of the additional reporting features of InfoSWMM 2D.

Exercise 12A Initialize the InfoSWMM 2D Model

In this exercise, you will create a 2D Model in InfoSWMM.

1. Open the project located at C:\Training\InfoSWMM\Ch12\Ch12Start.mxd

2. InitializeInfoSWMM ()

3. Set the scenario to ‘EXISTING_100YR’

4. Choose add data () from the ArcMap toolbar

  1. Browse to C:\Training\InfoSWMM\Ch3, select ‘elevation’, and click
  2. NOTE: This will add the elevation raster to the map

8. Save the project as Ch12End.mxd with its associated ISDB folder



10. Display the InfoSWMM 2D Toolbar by selecting Customize Toolbars on the ArcMap Menu

  1. Move the Toolbar for InfoSWMM 2D next to the Network and Elevation Raster you just added to the Map

12. Create the InfoSWMM 2D Database

13. Click Yes to Make the DB

14. The ICONS are now active, and you will a 2D Layer in the Arc Map TOC

Exercise 12B Create a Simulation Polygon

2D Simulation Polygons are used to define the boundary of mesh generation for a 2D simulation. Initial values for level, depth and velocity can be applied to the 2D Simulation Polygon using a 2D Initial Conditions object.

  1. Create the 2D Simulation Polygon by selecting the 1st Icon and drawing a polygon on the Elevation Raster. The Type is 2D Simulation Polygon. We will use an ID of My2D
  2. These are the default parameters for the created 2D Simulation Polygon. You can see the Polygon parameters on the 2D Tab of the InfoSWMM Attribute Browser.

Exercise 12B Create a Flood Type for Each Node in the Network

  1. Using the DB Editor change the DB Table for Junctions to a Flood Type of 2D and a Flood Discharge Coefficient of 0.05
  2. Flood Type – Flood Type – User option for what happens when nodes flood. None means that the excess flow is a loss out the top of the node. 2D means that flooded water flows out to the 2D mesh associated with the Node. Inlet means that either a HEC-22 type inlet is used to convey the excess flow from an overland flow node. The options for Inlets are: (1) Continuous Grate, (2) Continuous Curb-Opening, (3) Sag Continuous Grate, (4) Sag Continuous Curb-Opening or (5) Sag Combination.

Exercise 12C Mesh the Network

  1. Click on Mesh 2D Simulation Polygon and choose the Elevation Raster
  2. After Meshing click on the Meshing Log to check if there were meshing errors and to see how many mesh triangles were created.
  1. The created Mesh (depending on how you drew the Simulation Polygon) has about 6500 triangles

Exercise 12D Turn on 2D Modeling in the Run Manger

  1. In the Run Manger 2D Tab use the defaults but turn on the 2D Simulation
  2. Run the model network and look at the report file, You should see a 1D and 2D modeling report
  3. Click on show Display Max Depth Icon
  4. Using the Output Report Manager make a Group Graph of the nodes shown on the Mesh and view the Node 2D Inflow
  5. Clear the Map so more Polygons can be added to the Simulation Polygon

Exercise 12E Create a Roughness Polygon

  1. Create a Roughness Polygon around the center of the model network Roughness Polygon objects are used as part of the mesh generation process carried out when undertaking 2D Modelling. They can be used to divide a 2D Simulation Polygon into regions of different roughness.
  2. Change the roughness to 0.2 on the 2D Tab of the InfoSWMM Attribute Browser

Exercise 12F Create a Mesh Polygon

  1. Create a Mesh Polygon around the center of the model network. Mesh Polygon objects are used as part of the mesh generation process carried out when undertaking 2D Modelling. They can be used to divide a 2D Simulation Polygon into regions of different mesh resolution or to define zones in which ground level modification is required (see below).
  2. Using Mesh Polygons for Ground Level Adjustment Mesh Polygons can be used to define specific zones in which ground levels are to be adjusted in the 2D mesh; to correct for road channels and curb depths for example. The ground level of elements within the Mesh Polygon is determined from the Ground Model used during the meshing process. Adjustment to ground model level is applied to mesh elements within the Mesh Polygon during simulation without modifying the source ground model.
  3. Use a minimum Mesh of 100 square feet
  4. Change the Background color of the Roughness and Mesh Polygons
  5. ReMesh the Network Again for the newer Roughness and Mesh Polygons. You can see the smaller Mesh Polygons
  6. There are now about 7500 mesh polygons
  7. Rerun the Model and view the Maximum Depth

Exercise 12 G Create a Raingage for the Simulation Mesh

  1. Add a Raingage to the 2D Simulation Polygon and set the Rainfall percentage to 100 percent
  2. You need to Remesh the Model as a Raingage was added
  3. Rerun the Model and view the Maximum Depth Results, the whole mesh now has a water depth
  4. Look at the Report File for 2D and see the total Rainfall on the 2D Mesh.

Exercise 12 H Create an Infiltration Polygon

  1. Draw an Infiltration Polygon using the Create 2D Polygon Tool

Exercise 12 I Create Infiltration Data

  1. Create an Infiltration Surface Infiltration Zone (2D) objects are used to represent the physical area within a 2D mesh to which infiltration applies. Areas of different surface types are represented by a set of non-overlapping infiltration zones. An Infiltration Surface describing the infiltration characteristics for a specific surface type can be associated with each infiltration zone. If no infiltration surface is specified, no infiltration will be considered within the infiltration zone
  2. Define the Horton Infiltration Data for the Mesh
  3. Add the Infiltration Surface to the 2D Simulation Mesh
  4. Remesh the Mesh for the added Infiltration data
  5. Run the Network and look at the 2D Mass Balance for Rainfall and Infiltration. Volume Lost is infiltration loss.
  6. Now lower the 2D time step to a value of 1 for the 2D Timestep Multiplier and rerun the model
  7. The Continuity error has been reduced

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