Unit Hydrograph Theory

Unit Hydrograph Theory
The role of unit hydrograph theory in the flood prediction process is to provide an estimate of streamflow given the precipitation. A unit hydrograph shows the temporal change in flow, or discharge, per unit of runoff from excess precipitation. In other words, the unit hydrograph shows how the flow of a stream will be affected over time by the addition of one unit of runoff. This module offers a thorough introduction to the use of unit hydrographs and the application of unit hydrograph theory in flood prediction. Through use of rich illustrations, animations, and interactions, this module explains key terminology and assumptions, outlines the steps in creation of a unit hydrograph, examines the issues surrounding application of unit hydrograph theory, and discusses important considerations for forecasters.