HEC-RAS

Criterion

Explanation

General Description

Hydrologic Engineering Center's River Analysis System (HEC-RAS) is a modeling platform that allows the user to perform one-dimensional steady flow, one and two-dimensional unsteady flow calculations, sediment transport/mobile bed computations, and water temperature/water quality modeling. The model is designed to perform one and two-dimensional hydraulic calculations for a full network of natural and constructed channels.

Model Domain

The model domain is flexible, specified by user.

Developer

US Army Corps of Engineers (USACE)

Hardware computing requirements

Processer 3.4 Ghz or higher for 1D model. 2D model: processors of > 3.2- 3.4 Ghz. >32 Gb RAM. 24-inch (or larger) dual monitors. Windows 7, 8, 8.1 and 10 64-bit only.

Code language

Visual Basic??

Original application

Modeling of hydrodynamics in river systems

Public/proprietary and cost

The model is available for the public to download

Physically or empirically based

Physically based

Mathematical methods used

One- and two-dimensional unsteady flow simulation, steady transport/movable boundary computations, water quality analysis.
Steady flow simulation: solution of the one-dimensional energy equation.
Unsteady flow simulation: hydraulic calculations for steady flow were incorporated into the unsteady flow module
Sediment transport/ movable boundary computations: 1D sediment transport from scour and deposition

Input data requirements

Geometry data, boundary flow/stage data, water quality data, meteorological data

Outputs

Flow, stage, velocity, water quality variables

Pre-processing and post-processing tools

New RAS mapper pre-processor tools allow users to extract 1D rivers, cross sections, storage areas and 2D model elements. RAS mapper is a post-processor generates inundation depth and floodplain boundary datasets, using geometry and computed water surface profiles.

Representation of uncertainty

None specified.

Prevalence

Widely applied in different river systems, potentially hundreds of applications worldwide.

Ease of use for public entities

Needs knowledge and experience in hydraulic and water quality modeling. Model parameterization and calibration are needed for new applications.

Ease of obtaining information and availability of technical support

The HEC-RAS website provides technical support to HEC-RAS users. The website provides resources for users to download software, learn how to use the model, resolve problems, report bugs, and suggest improvements to products and service. No phone or email technical support is available to non-USACE customers.

Source code availability

The HEC generally discourages the distribution of source code. The center will provide source code if requested, for importing to different computers or for modifying. Source code under development will not be distributed.

Status of model development

Version 5.0.5 is latest version and is now available. This version supersedes all previous versions.

Challenges in integration

Provides inputs and outputs ascii and binary, which can be processed in DSS format, aThe document could benefit from more information about sediment transport since this is a key issue for the Delta. Are there examples of use to simulate sediment transport in the Delta? What might be the limitations of HEC-RAS for use in the Delta?

Similarly for temperture and water quality, are the limitations similar to the those indientified for HEC 5Q? Has there been any application of water quality modeling in the Delta using HEC-RAS?

nd can be easily integrated with other models.