The HEC-HMS (Hydrologic Engineering Center - Hydrologic Modeling System) is a hydrology software of the U.S. Army Corps of Engineers.
It is designed to simulate the precipitation-runoff processes of dendritic drainage basins. It is designed to be applicable in a wide range of geographic areas for solving the widest possible range of problems. This includes large river basin water supply and flood hydrology, and small urban or natural watershed runoff. Hydrographs produced by the program are used directly or in conjunction with other software for studies of water availability, urban drainage, flow forecasting, future urbanization impact, reservoir spillway design, flood damage reduction, floodplain regulation, and systems operation.
The program is a generalized modeling system capable of representing many different watersheds. A model of the watershed is constructed by separating the water cycle into manageable pieces and constructing boundaries around the watershed of interest. Any mass or energy flux in the cycle can then be represented with a mathematical model. In most cases, several model choices are available for representing each flux. Each mathematical model included in the program is suitable in different environments and under different conditions. Making the correct choice requires knowledge of the watershed, the goals of the hydrologic study, and engineering judgement.
HEC-HMS was developed beginning in 1992 as a replacement for HEC-1 which has long been considered a standard for hydrologic simulation. It was written in the FORTRAN language and until 1984 could only be run on a mainframe computer. When desktop computers became popular the program was ported to the PC.
