HEC-RAS (acronym for Hydrologic Engineering Center and River Analysis System) is a computer program that models the hydraulics of water flow in natural rivers and other channels. Prior to the recent update to version 5.0, the program was one-dimensional, meaning that there was no direct modeling of the hydraulic effect of cross-section shape changes, curves, and other two- and three-dimensional aspects of flow. The release of version 5.0 introduced two-dimensional flow modeling as well as sediment transfer modeling capabilities. The program was developed by the United States Army Corps of Engineers to manage rivers, ports and other public works under its jurisdiction. Since his release in 1995, he has gained wide public acceptance.

The Hydrologic Engineering Center (HEC) in Davis, California, developed the River Analysis System (RAS) to assist hydraulic engineers in channel flow analysis and floodplain determination.[1] It includes numerous data entry capabilities, hydraulic analysis components, data storage and management capabilities, and graphical and reporting capabilities.

AutoCAD

HEC-RAS can be used in conjunction with AutoCAD. Using AutoCAD you can create a digital terrain model (Digital Terrain Modelː DTM) and you can count the sections from DTM and import them into HEC-RAS.

flood cloud

In 2018, Jacobs released an updated version of Flood Cloud that allows HEC-RAS users to run their flood models in the cloud.