Single‐Outlet Detention‐Pond Analysis and Design

Abstract

A desktop method is presented to analyze or size detention ponds and outlet facilities. Different initial conditions are allowed. When used for design purposes, the method determines the size of the outlet facility for a given pond. However, if the pond is inadequate to meet the design criteria set, the method determines the required stage‐storage relationship. The method is based on the usual reservoir‐routing technique that couples the hydrologic‐storage equation with an expression describing the flow through the outlet structure. The equations are rearranged in terms of several dimensionless parameters. A computer model is used to solve the governing equation using a finite difference scheme. The numerical results obtained in terms of systematically chosen combinations of the governing dimensionless parameters are generalized based on the concept of similarity. The generalized results are presented in chart form. Sample applications of these charts are illustrated.