This study examines the impact of anthropogenic activities on surface water quality in the Mithi River watershed, utilizing hydrologic and hydraulic modeling to assess the rainfall runoff process. The Storm Water Management Model (SWMM) is employed to simulate flow and evaluate water quality at various sites within the urban basin, revealing correlations between simulated and observed data. Results indicate that continuous discharge from Vihar Lake can significantly reduce biochemical oxygen demand (BOD) levels in the river, thereby improving water quality.