Overview: Flooding hazards have been continuously threatening the communities near the East River, recalling the urgent need for proper mitigation and adaptation. In this project, we build a SWMM model of the East River watershed, as well as an idealized stormwater drainage system at the Village of Bellevue. The effect of backwater is characterized by applying the water level of the USGS gage as the downstream boundary condition and comparing the discharge simulations from Kinematic Wave and Dynamic Wave transform methods. The impact of stormwater is characterized by building an idealized stormwater system at the Village of Bellevue near the East River. We change the pipe size from 18 inches to 72 inches to run simulations under 10-year, 50-year, and 100-year storms.