HEC-RAS Software


HEC-RAS was developed by the US Army Corps of Engineers at the Hydrological Engineering Center.  It is an integrated system of hydraulic modelling software designed for the 1D hydraulic analysis of open channels, bridges and culverts.  The software allows the simulation of flow in a variety of standard or user-defined channels.  The program will resolve both subcritical, supercritical and mixed flow regimes and models both branched (dendritic) and looped channel networks.   The system comprises a Graphical User Interface (GUI) steady and unsteady hydraulic analysis components, data storage and management capabilities, graphics and reporting facilities.   HEC-RAS replaces the widely used programs HEC-2 and UNET.  Version 4.1 includes both steady and unsteady flow modules.


The general data formats of the two computational modules are identical and it is possible to use the same system geometry for a steady or unsteady simulation.  The software is capable of modelling the following hydraulic features:

  • Weirs and bridges

  • Culverts, sluices and gates

  • Levees/flood banks

  • Branched/looped channels

  • Inflows/outflows

  • Floodplains

  • Channel encroachments

  • Ineffective/static flow areas

  • Blockages to the channel

  • Channel improvement

  • Ice formation

  • Manning’s and Colebrook-White roughness equations.

New features (version 4.1)

Several new simulation features have been added to the program since the 4.0 release. Version 4.1 of HEC-RAS includes the following new features:

  • New RAS Mapper Floodplain Delineation Capabilities

  • Hydrologic Routing Reaches within an unsteady flow model run

  • New Flow Data and Boundary Conditions Editor for unsteady flow

  • Contraction/expansion losses for unsteady flow

  • Minor losses for unsteady flow

  • New junction hydraulics option for unsteady flow

  • Groundwater leakage for storage areas

  • Water Quality Modelling enhancements

  • Sediment Transport Modelling enhancements

  • New User’s Manuals and Help System



  • Prices include 12 months’ maintenance.   

  • 12 months’ technical support is also available for £250 per licence.

CD-ROM includes

  • HEC-RAS Software (v4.1)

  • GeoRAS (for ArcViewTM, ArcInfoTM and ArcGISTM

  • Installation  instructions

  • User manual 

  • Hydraulic reference manual

  • Applications guide

  • Example application data files

  • GeoRAS user guide

  • System  Requirements

  • 32Mb RAM (128Mb for GeoRAS)

  • 12Mb hard disk space

  • WindowsTM 95/98/NT.2000

Relevant JBA Training Courses

  • Introduction to HEC-RAS 

  • Intermediate HEC-RAS 

  • Advanced HEC-RAS 

  • HEC-RAS Master Class 


  • Single user licence:  £100 CD-ROM and Adobe AcrobatTM manuals

  • Multi-user licence:    £250 CD-ROM and Adobe AcrobatTM manuals

Full payment in advance is required for all software