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NRCS has adopted the Corps of Engineer's HEC-RAS (Hydrologic Engineering Center's River Analysis System) for computation of water surface profiles. Use of the NRCS program WSP2 has been phased out as NRCS engineers become trained and experienced with HEC-RAS. The major advantage of this program are Windows-based graphics for input and output, program technical and financial support at the Corps of Engineers Hydrologic Engineering Center, future enhancements expected, and its use by other government agencies and private engineers.

HEC-RAS Program Download and Documentation

Visit the Corps of Engineers website: Hydrologic Engineering Center.
    The program is well documented, with user manual and technical reference manual from the help menu.

NRCS Empoyees take note: Your government computers require a CCE version which may be obtained from IT support staff.

More Information:
NRCS employees and conservation partners may contact the NRCS HEC-RAS Team with questions or to obtain further information. Email the HEC-RAS Team.


  Land use layers (NLCD 2016) for HEC-RAS 2D

Training Material

  Video shorts for various HEC-RAS operations  (web page)

PowerPoint developed for use with HEC-RAS 5.0 and newer:

   GIStoRASproceduresFor2D  (pptx, 8 MB)

Advanced training materials:     Streamflow Energy     Streamflow Momentum

Older PowerPoint presentations:

    Download Overview
    Download Water Surface Profiles
    Download Basic Input
    Download Bridges
    Download Culverts
    Download Other Features Part 1
    Download Other Features Part 2
    Download Junctions
    Download Drop Structures
    Download Inline Weirs
    Download Trouble Shooting
    Download Intro to Unsteady Flow

WRAS is a conversion program developed by NRCS that takes existing WSP2 data sets and converts them in HEC-RAS format for import into HEC-RAS. Users should be aware that significant differences exist between HEC-RAS and WSP2 as to the way topography is represented by cross-sections. Users are urged to become fully informed of all differences between the two models by reading the user manuals.

WRAS is written in Visual Basic 6.0, and requires Windows 95 or higher.  WRAS is CCE compatible, but also runs on non-CCE machines.

Download Version 1.1, dated 1/27/2004

TR-20 Rating Table Program

One reason for computing water surface profiles is to develop cross section rating tables used in the NRCS TR-20 program for flood routing of stream reaches. The WSP2 program developed these tables as an option. However, HEC-RAS does not automatically develop there tables in the correct format for TR-20. For this reason, a program (named Rating_Table.exe) was written by NRCS to take a HEC-RAS output file and develop rating tables formatted for input to TR-20. HEC-RAS has many optional output variables and allows the user to develop a customized table with certain desired information. This customized table, once created and saved, will be accessible for use whenever HEC-RAS is run on the various projects and plans organized by the user. The program was written based on output from HEC-RAS version 2.2. Download the zipped file


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