Hydraulic Engineering Center - River Analysis System
A computer
modeling program produced by the
Army Corps of Engineers. HEC-RAS is used for generating profiles of the
flood plain for a particular stream or river.
Geometric data concerning the stream and its major features are gathered using existing
topographic maps,
aerial photography,
survey, and
field reconnaissance. Cross-sections of the stream and measurements of bridges or culverts are entered into the system.
Hydrologic data (basically just
flow rates) are generated using another program, often
HEC-HMS or its predecessor,
HEC-1. Typical storm events that are studied are the 10, 25, 50, 100, and 500-yr storms. This information is also entered into the system.
HEC-RAS performs lots of maths on this data and generates water levels for the stream. These water levels are used for many purposes, such as
flood insurance, emergency planning, and municipal codes on new construction.
HEC-RAS is a
GUI replacement for
HEC-2, with many new features and updated formulae. HEC-RAS version 3.0.1 was released in April 2001.
Haestad Methods, Inc. distributes and supports this software.
Sources: Me, HEC-RAS about file, HEC-RAS Application Guide.