Introduction
NRCS has adopted the Corps of Engineer's HecRas (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 HecRAS. 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.
Program and supporting materials available
HecRAS program
Link to web site for download of CCE-Certified version of HecRAS.
(CCE versions are for use on NRCS platforms. The public should download the
non-CCE version)
The non-CCE version may be downloaded from
the corps at the
HEC website.
HecRAS Documentation
The HecRAS package includes several documents. Each document is designed to help
the modeler learn to use the particular aspect of the modeling system. HecRAS
User's Manual is a guide to using HecRAS. The manual provides an
introduction and overview of the modeling system, installation instructions, how
to get started, a simple example, detailed descriptions of each of the major
modeling components, and how to view graphical and tabular output. HecRAS
Hydraulic Reference Manual describes the theory and data requirements for
hydraulic calculations performed by HecRAS. Equations are presented along with
the assumptions used in their derivation. Discussions are provided on how to
estimate model parameters, as well as guidelines on various modeling approaches.
HecRAS Applications Guide contains a series of examples that demonstrate
various aspects of HecRAS. Each example consists of a problem statement, data
requirements, general outline of solution steps, displays of key input and
output screens, and discussions of important modeling aspects.
Download CORPS Documentation from Hydrologic Engineering Center:
WRAS
WRAS is a conversion program developed by NRCS that takes existing WSP2 data
sets and converts them in HecRAS format for import into HecRAS. Users should be
aware that significant differences exist between HecRAS 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, HecRAS
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
HecRAS output file and develop rating tables formatted for input to TR-20.
HecRAS 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 HecRAS is run on the
various projects and plans organized by the user. The program was written based
on output from HecRAS version 2.2. Download the zipped file
Rating.zip.
Introduction to HecRAS Course
The introductory training course is designed for engineers with some knowledge
of basic hydraulic principles and no prior experience with HecRAS. It was
developed by NRCS as a three-day course and has been presented in several
classroom settings. The materials may also be used for self-training. The Power
Point presentations include views of various HecRAS data input screens and the
examples include actual data for hands-on experience.
These files require a zip utility or
Powerpoint
Download Overview (10 mb)
Download Water Surface Profiles (4 mb)
Download
Basic Input (10 mb)
Download
Bridges (11 mb)
Download
Culverts (4 mb)
Download
Other Features Part 1 (6 mb)
Download
Other Features Part 2 (1.8 mb)
Download Junctions (1.4 mb)
Download Drop Structures (1.6 mb)
Download Inline Weirs (463 kb)
Download Trouble Shooting (1.1 mb)
Download Intro to Unsteady Flow (1.3 mb)
More Information:
NRCS employees and conservation partners may contact the
NRCS HecRAS Team with questions or to obtain further information.
Email the HecRas Team.
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