WMS:TR-20 Precipitation

In TR20, there are two different ways to define precipitation. Precipitation is defined by selecting the Job Control command from the TR20 menu. Then, select the Define Precipitation button to define precipitation over the entire watershed. You can define precipitation by using either a standard SCS rainfall distribution or by defining a custom rainfall distribution. If a custom rainfall distribution is used, you must define a custom rainfall distribution in the XY Series Editor. If one of the standard SCS rainfall distributions are used, you can select one of the following rainfall types:

• Emergency Spillway and Freeboard
• Type I: 24 hours
• Type II: 24 hours
• Type IA: 24 hours
• Type III: 24 hours
• Type II: 48 hours

For all the standard distributions, you must define the rainfall depth. For the dimensionless distribution, you must also define the rainfall duration. You only need to define the depth and/or duration of the rainfall for a custom distribution if one of the units entered in the XY Series Editor is dimensionless.

Related Topics

• TR20 Overview
• Editing TR20 Parameters
• Entering Job Control Parameters
• Obtaining Precipitation Data