A Water Quality-Quantity Model for Avcilar Campus of Istanbul University Incorporating LID Implementation

Rainwater management practices are implementations for improvement of storm water quality and quantity. Implementation of these practices in urban areas is vital because urbanization results in low percentage of permeable soil and cuts off the ground water recharge. Over impermeable surfaces, rain quickly turns into surface runoff and causes flooding. With urbanization, contaminants, which accumulate over the surface, increase and therefore, the contamination of the surface runoff also increases. A number of precautions and control mechanisms are needed to remove these contaminants from the surface runoff which are called as Low Impact Development (LID) Best Management Practices (BMP). LID-BMPs serve for protection of the hydrologic cycle, ecological balance, reduction of the flood risk and improvement of surface water quality. In this study, first, a hydrological model for Avcılar Campus of Istanbul University is developed by using Environmental Protection Agency Storm Water Management Model (EPA SWMM). Then, the water quality model is integrated into the hydrological model by defining various land use types such as low-density residential, high-density residential, highway commercial and highway, and pollution parameters such as total suspended solid (TSS) and lead (Pb). Finally, several LID implementations such as green roof, permeable pavement, bioretention, rain garden, and rain barrel, are defined into the model according to the settlement type on the campus. The impact of the LID implementations on the water quality and quantity are observed. Model results show that the LID implementations greatly reduce the peak discharge. Moreover, LID implementations also decrease pollutant concentrations in surface runoff.