Urban watersheds have been a centerpiece among communities over the last few decades. Every growing urban watershed requires a system designed to store rainwater (runoff). Hence, estimating the amount of runoff and runoff generation percentage of different parts in an urban catchment system is substantial. Therefore, this was set as the cornerstone for assessing the hydrological response of different homogenous units of our study area. To this aim, land use maps were prepared for three different years (i.e. 1996, 2006, and 2016) using available archived data, census blocks obtained from National Cartographic Center, and satellite images in ArcGIS platform. Afterwards, the impact of land use changes on the peak discharge was analyzed over these years using ASSA (CivilStorm) software. The results revealed that the peak discharge in 2016 is significantly higher than the years before which stems from the increasing pattern of impermeable surfaces, in such a way that a 26% increase in impermeable surfaces from 1996 to 2016 has consequently increased the discharge by 24%.