Download page What is in the Rest of this Document?.
What is in the Rest of this Document?
The remainder of this document illustrates application of program HEC-HMS, following generally the steps described above. The table below describes the examples used. Choices made for the examples illustrate use of various program features; they are not intended as guidance for model configuration, calibration, or application. A professional hydrologic engineer should be consulted for such guidance, as that must be tailored to and appropriate for the study at hand.
Note: Data for the examples presented herein were adapted from actual studies. However, the data have been modified as necessary to illustrate key points. Consequently no conclusions regarding decisions made in the actual studies should be drawn from the results presented.
This section illustrates application of HEC-HMS in analysis of urban flooding. The goal of the study described is to evaluate the impact of changes in land use in a watershed. Historical data are used for calibration, and a frequency-based design rainfall event is the basis of comparison of runoff with and without the development.
Flood frequency study. Quantiles - flows of a specified annual exceedance probability - are required for a variety of studies. This section illustrates application of HEC-HMS to develop quantiles for an ungaged catchment.
Flood-loss reduction studies rely on flood-damage reduction benefit computations, and those require flow-frequency functions. HEC-HMS can be used to develop such functions, and this section illustrates that. Functions are derived for the without-project condition and for a damage-reduction alternative that includes a detention and diversion.
Flood warning systems can reduce flood damage in many watersheds by increasing warning time. HEC-HMS can provide information required to design and to evaluate such a system. The example in this section illustrates how HEC-HMS can be used to estimate the increase in warning time possible with such a system.
Capacity studies are undertaken to ensure that reservoir spillways can safely pass the probable maximum storm. This section illustrates configuration and application of HEC-HMS to develop the probable maximum flow and route it through a reservoir. An alternative spillway configuration is evaluated.
Increased vegetation, often a component of stream restoration projects, affects the hydrograph timing and the stage. HEC-HMS can provide hydrologic information needed to evaluate these projects. This section illustrates how HEC-HMS can be used to evaluate different levels of vegetation in a channel.
Surface erosion and sediment routing studies. This section describes how HEC-HMS can be used to generate important watershed erosion and sediment routing information. The results produced from an HEC-HMS erosion and sedimentation model can be a valuable resource in watershed management.
Streamflow forecasts provide hydrographs (time of flood flows and volume) and peak flow estimates to inform reservoir operation. This section illustrates how forecasts can be developed using a precipitation-runoff model of the watershed.