Prediction of Sediment Basin Performance

ABSTRACT PUBLIC Law 92-500 requires the control and reduction of point and nonpoint pollution to meet the 1983 water quality standards. Current legislation in several states requires the use of sediment detention basins to control pollution from strip mining and construction activities. It is envisaged that sediment basins may successfully be employed to control the nonpoint pollution associated with agriculture and silviculture. This paper presents a mathematical model for describing the sedimentation characteristics of detention basins. Using data generated by the model, the significance of the factors determining sediment deposition in esti-mating basin trap efficiency and peak effluent sediment concentrations has been analyzed. Regression equations are presented for estimating trap efficiency and peak effluent sediment concentrations from basins equipped with either a perforated riser or a drop inlet riser. The effects of selective withdrawal from the basin have been studied as well as the effect of sediment accumulations in the basin on the trap efficiency. The model has been tested in simulation studies on several actual basins and appears to give a good estimate of measured trap efficiencies.