Download GeoHECRAS v3.1.0 Download GeoHECRAS v3.1.0 CivilGEO GeoHECRAS GeoHECRAS is a specialized engineering software developed by CivilGEO that extends the capabilities of the U.S. Army Corps of Engineers’ HEC‑RAS hydraulic modeling engine. It’s designed to make river modeling, floodplain mapping, and bridge/culvert analysis much faster and more intuitive by combining CAD, GIS, and hydraulic tools