WMS:TR-20

TR20 models can be defined in WMS using the commands in the TR20 menu and resulting dialogs. There are six steps in defining a TR20 model using WMS:

Create a Topologic Tree

In the absence of terrain data, this is done using the commands to build the tree in the Tree menu. When using the TIN, Map, or DEM modules to delineate a watershed and sub-basin boundaries, a topologic tree is automatically created. Diversions can not be created directly on a TIN or in the Map module, but must be created using the commands in the Tree menu.

Define Job Control Parameters

Job control parameters are used to define the time and length of a simulation, output diagnostic controls, and other miscellaneous items. Definition of these parameters is discussed in detail later in this chapter.

Edit Basin/Outlet/Reservoir/Diversion Data

Parameters for all sub-basin outlets, reach routes, reservoirs, and diversions (hydrograph stations) are entered/edited using the Edit TR20 Parameters dialog accessed from the TR20 menu. This dialog displays current values and lets you edit values for the currently selected hydrograph station.

Model Check

This step allows you to check your TR20 data prior to performing an analysis. It reports errors such as zero area, undefined precipitation, etc. These errors should be corrected by returning to previous steps before actually trying to run TR20.

Run TR-20

WMS creates TR20 files compatible with any version of TR20. However, a Windows (X-Windows on UNIX and MS-Windows on PC's) compiled version of TR20 is distributed with WMS so that it can be run without leaving the WMS environment.

For an in depth description of the TR20 runoff model itself, refer to the TR20 User's Manual.

View Hydrographs

Once a TR20 simulation has been run you can view resulting hydrographs using the commands in the Hydrographs menu. After viewing the hydrographs, you may wish to repeat the previous steps in order to calibrate a model, or look at different scenarios.

Related Topics

• Editing TR20 Parameters
• Reading TR20 Input Files
• Saving TR20 Input Files
• Running a TR20 Model