This project emphasized the importance of having accurate maps and tools in order to better estimate current risk, manage the floodplain, invest funds and be prepared for major storm events. The floods that occurred during Memorial Day 2015 were used to validate the models, ensuring an accurate depiction of the flood risks.
Fort Bend County, Texas, is one of the fastest growing counties in the country, experiencing significant development in the last decade. In an effort to better represent flood risk, FEMA updated the flood hazard maps and models in 2006. These maps and models have been used for the past decade to accomplish floodplain management efforts, issue permits and design infrastructure.
The studied area encompasses a complex system, including the Brazos River, several natural waterways, man-made channels, diversion structures, dams, gated structures, natural overflow areas, levees, pump stations and a relatively flat topography.
At the time of the development of the current hydraulic models, limitations in the modeling software made it necessary to make some assumptions at key components of the system, such as using rating curves to represent diversion of flows.
FNI has been working with the City of Sugar Land, Fort Bend County Drainage District, and other regional stakeholders to update the H&H models for this area in order to better define the risk and make more informed decisions for the design of future infrastructure and analysis of new developments. The new hydraulic model utilizes the 2D modeling routines available in the latest version of HEC-RAS; takes the existing drainage network into account; and provides flexibility when evaluating local storms, floods on the Brazos, or a combination of both. These tools provide public officials with the information needed to better manage the floodplain and protect the public.