HEC-HMS

HEC-HMS (Hydrologic Modeling System) is a hydrologic modeling program developed by the United States Army Corps of Engineers Hydrologic Engineering Center (HEC). It is used to simulate the complete hydrologic processes of dendritic watershed systems, from precipitation and runoff to flow in streams, reservoirs and diversions.

HEC-HMS is an integrated system of software modules designed to simulate the runoff and routing of water in catchments and channels under various hydroclimatic conditions. The components of the HEC-HMS system include:

- Catchment Modeling - Modeling runoff in subbasins with loss methods such as SCS Curve Number, Green and Ampt or Soil Moisture Accounting, and Clark, Snyder or SCS unit hydrographs.

HEC-HMS enables users to accurately simulate and analyze watershed hydrology on both a small and large scale.

- Channel Routing - Modeling river and stream flows using Muskingum-Cunge, Modified Puls, Lag, Normal Depth or kinematic wave routing methods.

- Reservoir Modeling - Representing lakes and reservoirs with elevation-storage-discharge data or physical spillways and outlets, plus pumps and diversions.

- Sediment and Water Quality - Modeling surface erosion, channel sediment transport and nitrogen and phosphorus transport in the basin model.

- Meteorology - Modeling precipitation, evapotranspiration and snowmelt using gage, gridded (radar) and synthetic storm methods such as frequency storms and HMR52.

- Simulation Results - Viewing results on the basin map and in summary tables, time-series tables and graphs for any element.

- GIS Connection - Delineating watersheds and creating basin models from a digital elevation model with the built-in GIS tools.

- Model Optimization - Estimating parameters automatically by comparing computed flows with observed discharge.

- Forecasting and Uncertainty - Forecasting streamflow in real-time mode and assessing model uncertainty with Monte Carlo analysis.

- HEC-DSS Storage - Storing simulation results in the HEC-DSS Data Storage System for use with other programs such as HEC-RAS.

HEC-HMS is a widely used tool for hydrologic modeling and analysis. It is used by professionals in the fields of hydrology, hydraulics, and water resources to study water availability, urban drainage, flow forecasting, future urbanization impact, reservoir spillway design, flood damage reduction and floodplain regulation. The program is free for anyone to use and is available for Windows, macOS and Linux, although HEC provides user support only to Corps of Engineers users.