Pollutant load evaluation in stormwater systems

Stormwater runoff contains nonpoint pollution, and it is one of the main sources of water quality deterioration for receiving waters. Therefore, the control of nonpoint pollution should be considered to the same extent as the control of stormwater flooding in stormwater management. In order to control nonpoint pollution, structural best management practices (BMPs) are widely applied. Until now, however, many proposed models for BMP performance were not straight forward in their simulation of nonpoint-pollution removal because there are many uncertainties for nonpoint source pollutants removal in BMPs. The estimation and control of pollutant loading are very significant with respect to determining compliance with the Total Maximum Daily Load (TMDL) requirements. Thus, it is necessary to investigate how effective BMPs are at controlling pollutant loads in stormwater storage systems and which of their properties are the least and most effective in controlling the pollutant loads they treat. The objective of this study is to estimate the pollutant loading controlled and released to receiving water by BMPs using a BMP performance model. This BMP performance model will relate the BMP surface area and the imperviousness ratio of the study watershed to the effectiveness of two BMPs in removing watershed pollutants. The developed BMP performance model is applied in this study to detention basins and retention ponds; Total suspended solids (TSS) is chosen as the representative stormwater pollutant.