This Applications Guide illustrates use of the Hydrologic Engineering Center's (HEC) Hydrologic Modeling System (HEC-HMS) in studies typical of those undertaken by hydrologic engineers of the U.S. Army Corps of Engineers (USACE). The eight study chapters are Urban Flooding Studies; Flood Frequency Studies; Flood Risk Management (FRM) Studies; Flood Warning System Planning Studies; Reservoir Spillway Capacity Studies; Stream Restoration Studies; Surface Erosion and Sediment Routing Studies; Flood Forecasting Applications.
Data for the examples presented herein were adapted from actual studies. However, the data have been modified extensively to illustrate key points. Consequently, no conclusions regarding decisions made in the actual studies should be drawn from the results presented.
Many engineers, computer specialists, student interns, and contractors have contributed to the writing and production of previous editions. Each one has made valuable contributions that enhance the overall success of this Applications Guide. Nevertheless, the completion of the original edition was overseen by Matthew J. Fleming (Chief, Hydraulics and Hydrology Technical Division, HEC) while Christopher N. Dunn was Director of HEC.
The original guide recorded an update using HEC-HMS Version 4.2. The October 2026 revision updates guidance references and adds explanations of applicable methods and software features. The historical Case Studies retain their original procedures, parameter values, and results; this revision does not establish that they were rerun with a single current software version.
Using the Updated Guide
Read each chapter's Background and References for current guidance and its applicability. Callouts distinguish the historical example from developments that may affect a new study:
- Info (blue): historical context for the Case Study.
- Tip (green), Current HEC-HMS.: applicable software features and documentation.
- Note (yellow), Current guidance.: guidance or methodology that may change the approach for a study performed today.
Apply the guidance, methods, and review requirements appropriate to the actual project. The examples illustrate modeling choices; they do not replace a study-specific technical plan.