City of Houston has developed its first comprehensive city-wide drainage model. The goal of the Stormwater Infrastructure Model is to model the main drainage infrastructure throughout the City to better understand the capacity of the storm sewers, overland flow routes, and interaction with the channels and bayous. These models will allow the city to communicate flood risk to existing residents and improve planning for capital projects. Civitas developed two 1D-2D models for the Sims Bayou watershed in Infoworks ICM. The models were simulated for the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year storm events to provide comprehensive flooding information across the city. Each storm event was simulated for 48 hours and included local Atlas 14 rainfall, offsite hydrology where applicable, and discharges and stages from the Harris County Flood Control District’s MAAPnext models. Each model was validated with flood claim data from three historical storms: Memorial Day 2015, Halloween 2015, and Harvey 2017.