New Floodplain Delineation Capabilities in HEC-RAS

The Hydrologic Engineering Center's River Analysis System (HEC-RAS) is widely used for computing water surface elevations with results processed using GIS to determine inundation extent and flood depths. These floodplain boundary and flood depth results are used to establish flood insurance rate maps, analyze severe flood events, establish emergency action plans, estimate flood damage losses, and evaluate habitat restoration alternatives. New floodplain delineation tools in HEC-RAS provide the capability to develop inundation maps utilizing water surface profile results and a model of the ground surface. This delineation capability allow the modeler to visualize the resulting floodplain directly within HEC-RAS, providing a more efficient environment for hydraulic model refinement than processing results in GIS. The resulting floodplain boundary and flood depths may then be used in other modeling software to evaluate floodplain impacts.