Model Construction:Defining a uniform precipitation event

Rainfall can be input in one of three formats:

• Uniform constant rainfall over the entire watershed.
• Single temporally varying rain gage.
• Multiple, temporally varying rain gages.

All rainfall types in GSSHA must be tied to a specific point in time by specifying the year, month, day, hour, and minute of each rainfall data point. The GSSHA Precipitation dialog in WMS allows you to specify the type of rainfall and enter the necessary data associated with the rainfall type (Figure 5).

Figure 5. GSSHA Precipitation dialog. Accessible from the GSSHA menu in the 2-D grid module, this dialog is used to define precipitation events. WMS currently supports only the capability to simulate a single-gage event or uniform precipitation. Precipitation patterns that include multiple gages and/or multiple events must be developed in a text editor external to WMS. See the GSSHA User’s Manual for more information on the format of the precipitation input file

For a spatially uniform constant rainfall, the specified rainfall covers the entire basin for the specified period. The input parameters are:

• Rainfall Intensity - (mm/hr).
• Rainfall Duration - (minutes).
• Start Time.
  1. Year
  2. Month
  3. Day
  4. Hour
  5. Minute

Temporally and spatially varied precipitation is discussed in Chapter 9.

Related Topics

GSSHA Wiki Main Page
Primer Main Page

Model Construction

Global parameters

Total time

Time-step

Outlet information

Units

Defining a uniform precipitation event

Describing overland flow

Overland flow routing options

Verifying the basic model

Editing the grid to correct elevation errors

Determining an appropriate time-step

Running GSSHA