Time of Concentration of Overland Flow

Abstract

A mathematical model based on kinematic overland flow and Green‐Ampt infiltration is developed to calculate the time of concentration of overland flow on a rectangular plane surface. The governing equations of the rainfallinfiltration‐overland flow process are written in terms or various dimensionless parameters. The relative time of concentration, defined as the ratio of the time of concentration of an infiltrating plane to that of a geometrically identical impervious surface, can be expressed in terms of only two other dimensionless parameters. These parameters are physically based and they account for the subsurface soil properties and the antecedent moisture content. The results, presented in chart form, can be used for predicting the time of concentration of a rectangular plot under constant‐intensity rainfall.