Treatment of Stormwater Runoff from Construction Sites by Vegetative Swale

Land development especially construction works increases stormwater volumes and pollution loads to rivers and lakes. The temporary drainage system at construction sites particularly during construction stage discharges a large amount of pollutants that can damage the aquatic system of the receiving water bodies. Vegetative swale, one of the Best Management Practice (BMP) was evaluated to alleviate this problem. In this study, stormwater runoff from a construction site was treated by passing it through a vegetative swale. The effluent were analysed for its quality and then were compared with the Interim National Water Quality Standards for Malaysia. The results indicate chemical oxygen demand (COD), total suspended solid (TSS), Iron and Zinc could be reduced by 85.4%, 80.8%, 52.8% and 96% respectively. Removal of nitrate and phosphorus by the planted vegetations was up to 69% and 21% for the infiltrated water. However the nutrient removal by surface flow is negligible. In conclusion, the vegetative swale was able to improve the water quality of the stormwater runoff from construction site from Class V to Class III according to the Interim National Water Quality Standards for Malaysia.