A logical approach to the design storm concept

Abstract

Flood estimation using isolated event simulation models requires selection of a suitable combination of design storm and antecedent conditions. Current practice in storm drainage design is to adopt arbitrarily a storm duration, profile, and catchment wetness and to assume that the return periods of rainfall depth and flood peak are equal. This paper describes how sensitivity analysis may be used to examine the relationship between rainfall and flood return periods and, thereby, to determine systematically a suitable set of design inputs which give a peak runoff of the required return period. This process permits this particular model to be used with confidence in design as well as in simulation.