HEC-HMS
Description:
The Hydrologic Modeling System (HEC-HMS) is designed to simulate
the precipitation-runoff and flood processes ofwatershed systems.
It is ideal for solving problems in geographic areas ranging
from small urban or natural watersheds to large river basins.
The program will generate hydrographs and datasets that can
be used with other software for studies on such things as
water availability, urban drainage, flood damage reduction,
and flow forecasting.
HEC-HMS features a completely integrated work environmen including a database, data entry utilities, computation engine, and results reporting tools. The graphical user interface allows for seamless transitions between the different parts of the program.
Capabilities:
HEC-HMS has a broad range of applications for conducting hydrologic
simulations. These include:
• Physical Description of Watersheds:
Using a basin model, the user can simulate a number of runoff
processes. Elements available for this purpose include subbasin,
reach, reservoir, diversion, sources, and sinks.
• Hydrologic Simulations: HEC-HMS
can model infiltration losses using a variety of methods (curve
number, exponential, Green-Ampt, etc). The model will also
simulate surface runoff from excess precipitation, baseflow
contributions to subbasin outflow, and flow in open channels
with a variety of hydrologic routing methods. The user can
also control starting and ending dates and times, as well
as time intervals and meteorological cycles (evapotranspiration,
snowmelt, and precipitation).
• Parameter Estimation: HEC-HMS can
estimate most parameters for methods included in subbasin
and reach elements, as well as any element upstream of the
observed flow location. The program also boasts six functions
to estimate the accuracy of the computed results compared
to the observed discharge.
• Analysis of Simulations: For simulations
that have a meteorologic model that use the frequency storm
method, the user as the option of telling the program to automatically
adjust the storm area and generate peak flows accordingly.
• Connection to GIS Programs: A compatible
GIS program, HEC-GeoHMS, is
available and can be used to create basin and meteorologic
models that use elevation data and geometric algorithms to
quickly and easily identify drainage boundaries of watersheds.
Limitations:
There are two main limitations that arise in HEC-HMS
due to the way the software was designed and developed.
• Simplified Model Formulation: The
choice to simplify the model formulation was made so that
the program would be able to run simulations very quickly
while producing results that are both accurate and precise.
• Simplified Flow Representation:
By simplifying the flow representation, the efficiency of
the model is maximized while also minimizing the size of the
program and run-time of simulations.
Basic Inputs:
• Watershed data (elevations, boundaries,
soil characteristics)
• Simulation time information (start and end
dates and times, time intervals)
• Mathematical model to use for mass or energy
flux simulation
• Meteorological data (precipitation, snowmelt,
evapotranspiration, etc)
Basic Output:
• Hydrographs
• Comparisons of simulated results to observed
data
• Datasets for use with other software
How to Run the Model:
HEC-HMS is a generalized modeling system capable
ofsimulating scenarios in a various types of watersheds.
• Begin by constructing a watershed in a new
file or importing data from an existing file. If you are creating
a new watershed, do so by breaking down the hydrologic cycle
into manageable pieces. Be sure to define the watershed's
boundaries.
• Any mass or energy flux can then be simulated
using one of HEC-HMS' integrated mathematical models. While
there are a number of models available, select the one that
is most suitable to the purpose of your hydrologic study and
the particular conditions and characteristics of your simulation.
• Run the simulation and view the hydrograph(s)
produced. Compare these results with observed data.
Developer: HEC-HMS was developed by the U.S. Army Corps of Engineers' Hydrologic Engineering Center
Faculty Contact:
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