Suspended Solids Removal in Detention Basins

Abstract

Detention basins are being used to improve the quality of stormwater discharges from urban areas. While the design of detention facilities for quantity control is fairly well understood, the same cannot be said for the design of basins to improve water quality. It appears that no theoretical arguments can be made for using design storms and steady‐state assumptions to predict the suspended solids removal capability of stormwater detention basins. A more logical course would be to investigate long‐term performance. This paper demonstrates an approach for estimating the long‐term performance of detention basins with respect to suspended solids removal. The approach involves the simulation of detention basin behavior, and it is described and demonstrated with a hypothetical case study in which the Storm Water Management Model (SWMM) was used to produce performance information over large ranges of storage capacity and discharge capacity. The comprehensive information that can be generated by such a simulation gives an engineer significant guidance for the planning and design of a detention basin.