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HEC-RAS is a computer program that models the hydraulics of water flow through natural rivers and other channels. The program is one-dimensional, meaning that there is no direct modeling of the hydraulic effect of cross section shape changes, bends, and other two- and three-dimensional aspects of flow. The program was developed by the US Department of Defense, Army Corps of Engineers in order to manage the rivers, harbors, and other public works under their jurisdiction; it has found wide acceptance by many others since its public release in 1995.

3D view

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

How it works[edit]

The basic computational procedure of HEC-RAS for steady flow is based on the solution of the one-dimensional energy equation. Energy losses are evaluated by friction and contraction / expansion. The momentum equation may be used in situations where the water surface profile is rapidly varied. These situations include hydraulic jumps, hydraulics of bridges, and evaluating profiles at river confluences.

For unsteady flow, HEC-RAS solves the full, dynamic, 1-D Saint Venant Equation using an implicit, finite difference method. The unsteady flow equation solver was adapted from Dr. Robert L. Barkau’s UNET package.

HEC-RAS is equipped to model a network of channels, a dendritic system or a single river reach. Certain simplifications must be made in order to model some complex flow situations using the HEC-RAS one-dimensional approach. It is capable of modeling subcritical, supercritical, and mixed flow regime flow along with the effects of bridges, culverts, weirs, and structures.

Use[edit]

HEC-RAS is a computer program for modeling water flowing through systems of open channels and computing water surface profiles. HEC-RAS finds particular commercial application in floodplain management and flood insurance studies to evaluate floodway encroachments. Some of the additional uses are: bridge and culvert design and analysis, levee studies, and channel modification studies. It can be used for dam breach analysis, though other modeling methods are presently more widely accepted for this purpose.

Advantages[edit]

HEC-RAS has merits, notably its support by the US Army Corps of Engineers, the future enhancements in progress, and its acceptance by many government agencies and private firms. It is in the public domain and peer-reviewed, and available to download free of charge from HEC's web site. Various private companies are registered as official "vendors" and offer consulting support and add on software. Some also distribute the software in countries that are not permitted to access US Army web sites. However, the direct download from HEC includes extensive documentation, and scientists and engineers versed in hydraulic analysis should have little difficulty utilizing the software.

Disadvantages[edit]

Users may find numerical instability problems during unsteady analyses, especially in steep and/or highly dynamic rivers and streams. It is often possible to use HEC-RAS to overcome instability issues on river problems. HEC-RAS is a 1-dimensional hydrodynamic model and will therefore not work well in environments that require multi-dimensional modeling. However, there are built-in features that can be used to approximate multi-dimensional hydraulics.

HEC-RAS programs[edit]

Aquaterra[edit]

Aquaterra is a professional software for canals and river engineering works design. Seamless integration in CAD environment makes it very easy to learn and use. Engineers use Aquaterra to create detailed designs as well as for conceptual studies and designs. HEC-RAS interface is intended for communication between CAD environment and HEC-RAS. This module prepares the HEC-RAS geometric input file based on cross sections, banks and Manning coefficient data and transfers the resulting water levels back to Aquaterra.

ArcView[edit]

HEC-RAS can also be used in the GIS program ArcView (With 3-D analyst and Spatial Analyst extensions). ArcView can read-in AutoCAD drawings for backgrounds and can create a Digital Terrian Model (DTM). In a similar way to river CAD, Geo-RAS can be used to create cross sections and other geometric data for use in HEC-RAS and can be used to export water surface data from HEC-RAS back into ArcView to create flood maps with depths and extents of flooding.

RAS[edit]

HEC-RAS has a dll library that allows you to create an application for use without a user interface. This dll proved to be useful for advanced analysis such as Monte Carlo uncertainty. The freeware application ARAS[2] takes advantage of such capability, and allows to automate several tasks like running several plans of updating roughness. "RAS" : River Analysis System

AutoCAD[edit]

HEC-RAS can be used along with AutoCAD. A digital terrain model (DTM) can be constructed in AutoCAD and sections can be cut from the DTM and imported into HEC-RAS.

WMS (Watershed Modeling System)[edit]

WMS (Watershed Modeling System) provides pre and post-processing tools for use with HEC-RAS. The development of WMS was funded primarily by The United States Army Corps of Engineers. Commercial licenses to WMS are available from the developer, Aquaveo LLC.[3] Features include:

  • Use feature objects (centerline, cross section lines) and a TIN to develop the geometry of a HEC-RAS model.
  • Edit, merge, and create cross sections in a database for use with HEC-RAS and other hydraulic models.
  • Delineate flood plains from water surface elevation data. Water surface elevations can be computed by HEC-RAS, defined interactively, or imported from a file.
  • Link multiple simulations of HEC-1 to HEC-RAS to determine the uncertainty in modeling parameters on a delineated flood plain. Curve Number and Precipitation can be stochastically varied among HEC-1 parameters and Manning's n value for HEC-RAS.

HEC-Archives[edit]

  • HEC-Archives by Dodson & Associates, Inc.[4]

(needed: other vendors' products)

See also[edit]

References[edit]

  1. ^ HEC.usace.army.mil
  2. ^ Hometss.com
  3. ^ Aquaveo.com
  4. ^ a Dodson-hydro.com, free download site for archived versions of HEC-RAS and HEC-2]

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/HEC-RAS — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
26361 videos foundNext > 

HEC RAS Tutorial

HEC-RAS and Civil3D, Part 1 of 3

Exporting a HEC-RAS model from a Civil 3D surface. Part 1 of 3. Creating a quick and accurate floodplain model form a terrain model.

Running HEC RAS model with real data HD

HEC RAS Básico 1

Video en donde se muestra un ejemplo básico y practico para el diseño de un canal trapezoidal con el uso del HEC RAS.

Tutorial on Installing Single Culvert in HEC-RAS

This is a short tutorial on installing Single Culvert containing multiple barrels in HEC-RAS. In this video, the example problem of the Application Guide fro...

unsteady hec-ras analysis

Unsteady HEC-RAS analysis.

TUTORIAL: SIMULACIÓN BÁSICA CON HEC-RAS.

Bueno, aquí está el tutorial que algunos pidieron. Espero que les sirva.

WMS: Building a HEC-RAS Model

WMS contains an integrated interface for HEC-RAS. WMS is the ideal solution for building and visualizing HEC-RAS models. (Hydrology Modeling)

HEC-RAS Tutorial

This has become a bit rambling and clumsy. I shall add another one, crisp, but this is good for knowing how the simulation can be changed at any time.

Running HEC RAS model with real data -HD

26361 videos foundNext > 

9541 news items

 
iAgua.es
Mon, 15 Dec 2014 07:11:15 -0800

HEC-RAS en su versión 4.1.0 (Hydrologic Engineering Centers River Analysis System, HEC-RAS) hace parte del conjunto de software de próxima generación (“Next Generation”) del Cuerpo de Ingenieros del Ejército de los Estados Unidos. Este software ...

Prairie Business

Prairie Business
Fri, 19 Dec 2014 08:07:30 -0800

Glennon's broad range of software knowledge includes AutoCAD, Land Desktop, Civil 3D, HydroCAD, HEC-RAS and SketchUp. Originally from Hatton, N.D., Glennon holds a bachelor of science degree in civil engineering from North Dakota State University ...
 
lyonsrecorder
Thu, 23 Oct 2014 12:30:00 -0700

Diller is experienced in modeling in the Hydrologic Engineering Centers Rivers Analysis System, known as HEC-RAS. Before your eyes glaze over, that is important to know about, and here's why: the Town will ask for a HEC-RAS model from everyone who is ...
 
Water Online (press release)
Thu, 29 May 2014 22:54:09 -0700

Importation of HEC-RAS models now uses these new object types and includes the conversion of HECRAS bridges and culverts to the new XP Bridge Links. Improved Results Analysis.MultipleStorms and Scenario simulations can now display multiple HGL in ...
 
HydroWorld
Tue, 23 Jul 2013 12:27:22 -0700

For Safe Harbor Dam in Pennsylvania, preparation of the EAP involved creation of an unsteady-flow model using HEC-RAS software from the U.S. Army Corps of Engineers; calibration based on observed water surface elevations; and unsteady-flow ...
 
NOLA.com
Fri, 27 Dec 2013 14:59:16 -0800

FEMA relies on a computer model typically used to predict the flooding of rivers (HEC-RAS) rather one used for rain (SWMM5), which Gonzales said is more accurate. The parish also collected comments from individual property owners and neighborhood ...
 
Ten Links
Fri, 21 Mar 2014 08:56:15 -0700

LJUBLJANA, Slovenia, Mar 21, 2014 - CGS plus releases its latest version of Aquaterra 2014, software for canal and river engineering design for BricsCAD v14. Originally developed for AutoCAD and it´s verticals, Aquaterra has been first time ported to ...

Zumbrota News-Record

Zumbrota News-Record
Wed, 02 Oct 2013 11:33:05 -0700

2013 graduate Sarah Green presented an overview of the study at the Mazeppa meeting. MSU used GIS (Graphical Information System) for developing maps and organizational systems. Then LiDAR (Light Detection and Ranging), and HEC-RAS (Hydraulic ...
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