UG_210_21_3 - UG 210-21-3 ENG – HEC-HMS, Version 4.7.1, Computer Program
UG 210-21-3 ENG – HEC-HMS, Version 4.7.1, Computer Program
User Guide: 210-21-3 Date: April 5, 2021
Subject: ENG – HEC-HMS, Version 4.7.1, Computer Program

Purpose.  To announce availability of the U.S. Army Corps of Engineers (USACE) Hydrologic Engineering Center - Hydrologic Modeling System (HEC-HMS), Version 4.7.1 computer program and explain how to obtain the software and documentation.
Expiration Date.  Effective upon receipt.

Background.  HEC-HMS is hydrologic modeling software developed by the USACE Hydrologic Engineering Center (HEC) to simulate watershed rainfall and runoff processes. Version 4.7.1 corrects minor bugs in the previous version and adds additional capabilities, including upgraded computational techniques and a 2D Diffusion Wave Transformation originally developed for use in the HEC-RAS model.  Full documentation of changes is available in the release notes found at  

Special Instructions.  HEC developed HEC-HMS primarily for the Corps but distributes the software freely to the public for use without restriction. The user assumes all responsibility for the accuracy and suitability of this program for a specific application. HEC does not provide assistance or support for this
software to non-USACE users.

Distribution.  NRCS tested and CCE certified HEC-HMS Version 4.7.1 for deployment to NRCS Information Technology Services (ITS) supported workstations on March 5, 2021. The project reference
number is CRQ000003914310.

HEC-HMS Version 4.7.1 replaces all previous versions of HEC-HMS. This directive cancels, deletes, and replaces the previous notification User Guide 210-19-4: ENG – HEC-HMS, Version 4.3, Computer
Program, dated March 11, 2019.

NRCS users are to obtain the HEC-HMS 4.7.1 through their ITS managers, who can download and install the program. NRCS makes no official printing or distribution of program documentation, but users can download the documentation from the HEC-HMS webpage at

Filing Instructions.  Users wishing to retain paper copies of HEC-HMS documentation should place it in a three-ring binder adjacent to other technical directives. 


Contact.  NRCS does not have an established internal support framework specifically for HEC-HMS, however, NRCS users may direct general hydrologic modeling questions to the following individuals:

• Jon Fripp at or (817) 509-3771, National Design, Construction, and Soil Mechanics Center (NDCSMC)
• Karl Visser at or (817) 509-3763, NDCSMC
• Quan Quan at or (301) 504-3952, West National Technology Support Center (WNTSC), Water Quality and Quantity Team (WQQT)
• Jacob Diequez at or (301) 504-3956, WNTSC, WQQT

Contact Claudia C. Hoeft, National Hydraulic Engineer, Conservation Engineering Division, at or (202) 720-0772 with questions regarding this directive.     



Diane Gelburd

Deputy Chief for Science and Technology   


[UG_210_21_3 - ]