HEC-RAS

BOSS HEC-RAS is based on the U.S. Army Corps of Engineers’ HEC-RAS water surface profile model used for modeling both steady and unsteady, one-dimensional, gradually varied flow in both natural and man-made river channels.

» Overview

Overview

BOSS HEC-RAS is based on the U.S. Army Corps of Engineers’ HEC-RAS water surface profile model used for modeling both steady and unsteady, one-dimensional, gradually varied flow in both natural and man-made river channels.

Ease of Use

BOSS HEC-RAS is easy to learn and use, allowing the user to quickly define a river model to be analyzed. Data input is performed through interactive graphics and easy-to-use dialog boxes. There is no need for the user to struggle with cumbersome, cryptic, error-prone input card files. In addition, existing HEC-2 models can be directly imported.

Superb Graphics

BOSS HEC-RAS can display and plot several graphs, including cross-section plots, profile plots, rating curves, and 3-D river valley plots, allowing you to quickly evaluate the program’s results. All graphics can be viewed during data input, enabling the user to quickly examine the model for input errors.

Total user control is provided over line color, line width, and line type. Graphic plots can be output at any user-defined scale. Axis labels can be redefined, and the user can select what variables to display on the plots.
The program supports all Microsoft Windows output device drivers, allowing the graphs to be printed on any laser printer, plotter, or dot-matrix printer. In addition, plots can be pasted into other Windows programs, such as Microsoft Word® and WordPerfect®.


BOSS HEC-RAS can display and plot 3D river valley plots, cross-section plots, profile plots, and rating curves, allowing the user to quickly evaluate the program’s results.

Lots of Help

Wherever you are in BOSS HEC-RAS, extensive context-sensitive help is available to assist you through any difficulty. The professional documentation includes discussions on the theoretical basis of the model, data requirements, optional capabilities, bridge and culvert hydraulics, floodway computations, as well as a complete description on how to use the software.

Extensive context-sensitive help is available in BOSS HEC-RAS to assist the user through any difficulty.

Built-in Model Checker

Included with HEC-RAS is a built-in model checker. HEC-RAS’ model checker will check over the specified input data. If it encounters an error with the input data, it will explain what is wrong and how you can correct it. BOSS HEC-RAS’ model checker can be thought of as an expert modeler, pointing out any input data errors contained in the model.

BOSS HEC-RAS has a built-in model checker pointing out any input data errors contained in the model and how the user can correct it

The HEC-RAS Model

The HEC-RAS analysis model has several improvements over that of the original HEC-2 analysis model. HEC-RAS is capable of modeling subcritical, supercritical, and mixed flow regime water surface profiles. Other special features include optimization of flow splits, automatic roughness calibration, and multiple-opening bridge and culvert analysis.

BOSS HEC-RAS can model multiple bridges and culverts at a roadway crossing, evaluating each opening as a separate entity and distributing the total flow through the openings such that the energy loss in each is equal.
Floodway encroachments can be entered by the user to determine the change in water surface elevation. If desired, the user can specify the allowable change in water surface elevation, and the program will then compute the extent of the floodway encroachment. This is used to determine the allowable amount of encroachment that can be made to the existing floodway without adversely altering the water surface elevation.
The HEC-RAS model has the ability to automatically perform subcritical, supercritical, and mixed flow regime calculations. Mixed flow regime computations provide an accurate water surface profile, showing either subcritical or supercritical flow as controlling. However, detailed hydraulic jump locations are not computed. The model assumes that the hydraulic jump occurs between cross-sections.
HEC-RAS can model a single river reach, a dendritic river system, or a full network (looped system) of stream channels. An unlimited number of river reaches can be modeled. Energy losses at junctions (locations where river reaches combine or split) are accounted for by the model using ether an energy or momentum balance across the junction. The momentum balance allows the user to specify a rotation angle for each reach that is not parallel to the normal direction of river flow.

BOSS HEC-RAS can model a single river reach, a dendritic river system, or a full network (looped system) of stream channels. An unlimited number of river reaches can be modeled.
Included with HEC-RAS are completely new bridge and culvert hydraulic routines, allowing multiple bridges and culverts to be modeled at a single roadway crossing. In addition, other hydraulic structures, such as weirs and spillways, can be modeled. At multiple opening crossings, the model evaluates each opening as a separate entity and distributes the total flow through the openings such that the energy loss in each is equal. The bridge routines allow the modeler to analyze any shape or size bridge. Unlike HEC-2, HEC-RAS does not require a trapezoidal approximation of the bridge opening. Instead, the bridge opening is defined by the bridge deck, piers, and abutments as separate input items. The model automatically adjusts for low flow, pressure flow, roadway weir overflow, and highly submerged roadway overflow conditions. The culvert hydraulic computations have been improved over HEC-2, allowing multiple culverts of different size and type to be modeled at a single roadway crossing. Box, circular, arch, pipe arch, and elliptical culvert shapes are fully supported.
Included with HEC-RAS is a built-in bridge scour calculator, allowing you to compute and plot out the total scour at a bridge cross-section due to contraction scour, pier scour, and abutment scour. HEC-RAS uses the scour methodology provided by the Army Corps HEC Technical Publication No. 18. Contraction scour occurs from a reduction in flow area by a constricting bridge opening. Pier scour occurs from an acceleration of flow around a bridge pier, which results in the formation of vertical flow vortices that can create scour holes. Abutment scour occurs when a bridge abutment obstructs the stream flow, causing the formation of a horizontal flow vortex along the toe of the abutment.
HEC-RAS also supports an alternative method of computing conveyance for roughness subareas. This new method only breaks apart the conveyance sub-areas where the roughness values change. However, the method that HEC-2 uses (which looks at each piece of area between overbank ground stations as a separate conveyance subarea) is also supported.
BOSS HEC-RAS has a built-in report generator, producing detailed output enabling the user to quickly interpret the modeling results.