Runoff Capture and Delivery Curves for Storm-Water Quality Control Designs

Abstract

A storm-water quality control system consists of trickle channels and water quality control basins (WQCB). To be economical, a WQCB is often designed to capture rainfall events smaller than extreme events. In current practice, the design rainfall statistics and runoff capture rates for sizing a WQCB have to be derived from the local long-term continuous rainfall record. Such a rainfall-runoff simulation process is lengthy and time-consuming. In this study, the analyses of 30- to 40-year continuous rainfall data recorded from seven metropolitan areas in the United States indicate that the frequency distribution of rainfall event-depths can be described by an exponential decay function. Applying the exponential distribution to a complete rainfall data series, the normalized