HEC-HMS

HEC-HMS
Name	HEC-HMS
Developer	United States Army Corps of Engineers
Initial release	1998
Latest release	2020s
Programming language	C++
Operating system	Microsoft Windows
License	Public domain (USACE)

HEC-HMS HEC-HMS is a watershed-scale hydrologic simulation model developed by the United States Army Corps of Engineers for simulating the precipitation-runoff processes of dendritic drainage basins. It supports event-based and continuous simulation for planning, design, and research across flood forecasting, reservoir operations, and urban drainage applications. The system interfaces with geographic, meteorological, and hydraulic tools used by federal agencies, academic centers, and international organizations.

Overview

HEC-HMS integrates parameterized representations of precipitation, interception, infiltration, surface runoff, baseflow, channel routing, and reservoir operations used in analyses by National Weather Service, Federal Emergency Management Agency, United States Geological Survey, Environmental Protection Agency, and other agencies. The model pairs with spatial data produced by USGS National Map, National Oceanic and Atmospheric Administration, NASA Landsat, and European Space Agency missions for catchment delineation and meteorological forcing. HEC-HMS output commonly feeds into hydraulic models such as HEC-RAS, SWMM, and MIKE 11 for floodplain mapping and infrastructure design assessments used by entities like FEMA Region IV and metropolitan planning organizations.

History and Development

Development began under the USACE Hydrologic Engineering Center in the 1980s and 1990s, building on legacy water resources software from earlier Corps projects and research collaborations with Colorado State University, Massachusetts Institute of Technology, University of Iowa, and University of California, Davis. The initial public releases coincided with modernization efforts tied to post-1993 flood responses in the Midwest flooding of 1993 and guidance from the National Flood Insurance Program. Subsequent versions incorporated algorithms from academic literature published in journals like Water Resources Research, Journal of Hydrology, and Hydrological Processes, and integrated standards influenced by the National Hydrologic Modeling Conference and international workshops at IAHS. Major milestones include incorporation of continuous simulation, improved GUI, and expanded data connectors following collaborations with NOAA NCEP and USGS Water Mission Area.

Hydrologic Modeling Components

HEC-HMS provides multiple choices for key process modules: precipitation gage weighting and hyetograph specification linked to analyses used by NOAA, evapotranspiration estimators referenced by FAO, and infiltration methods such as SCS Curve Number derived from Soil Conservation Service guidance and research at USDA Natural Resources Conservation Service and University of Arkansas. Runoff transformation options include unit hydrograph approaches influenced by the work of Sherman (1932), kinematic and Muskingum routing techniques related to studies at Iowa State University, and baseflow separation methods developed in collaboration with USGS. Reservoir and diversion modules implement rule curves comparable to practice at Bureau of Reclamation and flood control operations used by Tennessee Valley Authority.

Applications and Use Cases

Practitioners use HEC-HMS for floodplain mapping supporting FEMA flood insurance studies, design storm analysis for transportation projects managed by Federal Highway Administration, urban drainage planning in cities such as New York City, Los Angeles, and London, and watershed restoration projects associated with EPA Superfund sites and Conservation Reserve Program efforts. It informs reservoir operation studies at facilities like Hoover Dam and Glen Canyon Dam, supports climate-change impact assessments referenced in reports by the IPCC and US Global Change Research Program, and underpins academic dissertations at institutions including Stanford University and Imperial College London.

Software Architecture and Data Formats

HEC-HMS is a Windows desktop application written in C++ with a modular project structure that stores models, time series, and spatial metadata in proprietary project files alongside common interchange formats. It imports and exports data via ESRI shapefiles, GeoTIFF rasters, and time-series formats compatible with NetCDF-based workflows used by NASA and NOAA. The software integrates with GIS via ArcGIS and supports scripting and automation through command-line interfaces and connectors used by teams at USACE Engineer Research and Development Center and consulting firms like AECOM and Jacobs Engineering.

Validation, Calibration, and Limitations

Validation studies compare simulated hydrographs against observed streamflow records from USGS National Water Information System gages and rainfall observations from NOAA NEXRAD networks. Calibration commonly employs optimization tools inspired by research at University of Arizona and algorithms such as Monte Carlo and genetic algorithms reported in literature from ETH Zurich and University of Newcastle. Known limitations include simplified representation of urban micro-scale hydraulics relative to detailed models like SWMM, sensitivity to precipitation input quality noted in studies by Princeton University and Colorado State University, and challenges in karst or highly-fractured terrains emphasized by researchers at University of Kentucky.

Adoption, Training, and Community Resources

Adoption is widespread across federal agencies, state departments of transportation, consulting engineers, and universities. Training and user support are provided by USACE Hydrologic Engineering Center workshops, university short courses at University of Colorado Boulder and Iowa State University, and commercial training offered by firms such as DHI and Hydrologic Engineering Consultants. Community forums, case studies, and model examples are shared through conferences like World Water Congress, American Geophysical Union meetings, and repositories maintained by USACE and participating academic partners.

Category:Hydrologic models