Detention Storage Volume for Small Urban Catchments

Abstract

To size storm-water detention basins, a volume-based method such as that of the Federal Aviation Administration is applicable to small urban catchments. However, the reliability of such a method depends on estimation of the average outflow. In this study, the average outflow from a detention basin is found to be related to the time of concentration of the catchment and the duration of the design storm. This modification eliminates judgment calls and warrants a consistency in volumes and flow rates between the design rainfall hyeotograph and the inflow and outflow hydrographs.