The U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center's River Analysis System (HEC-RAS) computer program supersedes its HEC-2 computer program, which was widely used in the preparation of studies and restudies for the National Flood Insurance Program (NFIP). The Federal Emergency Management Agency (FEMA) has adopted the guidance that hydraulic analyses for newly contracted studies and restudies of entire watersheds (with detailed HEC-2 hydraulic analyses) should be conducted using the HEC-RAS program instead of the HEC-2 program. This floodplain modeling manual is prepared as a guide to introduce the HEC-RAS Version 3.0 modeling procedures to engineers who have experience in preparing floodplain models with the HEC-2 computer program.
Resources related to the HEC-RAS program can be downloaded through the link below. These resources and an array of other useful FEMA, NFIP, and Map Mod resources are now located in the FEMA Library. To search for other resources in the FEMA Library, please click here.