Abstract
Almost all runoff from the semiarid rangelands of the Southwestern United States results from intense convective storms of short duration. Depth-duration values for precipitation for this region that are developed through standard procedures may be misleading when used for runoff design. Various combinations of short bursts of rain can, and do, plot on average depth-duration curves, but such curves have little practical meaning for small watersheds (100 square miles or less). For design purposes for small watersheds, depths of precipitation for relatively short periods (15-30-60 minutes) for varying return periods and areas are needed. For runoff design for larger watersheds two probability estimates may be needed—the probability of storms of certain intensities and size falling on tributary watersheds of finite sizes, and the probability of storms developing over a multi-tributary system in such patterns as to produce important volumes and peaks of runoff.

This publication has 0 references indexed in Scilit: