UG_210_20_8 - UG 210-20-8 ENG – HEC-EFM Version 4.0
UG 210-20-8 ENG – HEC-EFM Version 4.0
User Guide: 210-20-8   Date: September 29, 2020
Subject: ENG – HEC-EFM Version 4.0  

Purpose.   To announce the availability of the U.S. Army Corps of Engineers (USACE), Hydrologic Engineering Center – Ecosystem Functions Model (HEC-EFM), version 4.0 computer program and explain how to obtain the software and program documentation.    
Effective Date.   Effective upon receipt.  
Background.   The USACE Hydrologic Engineering Center (HEC) developed HEC-EFM as an analysis tool to support planning, implementation, and monitoring for flood damage reduction and environmental restoration measures.  It aids in analyzing ecosystem response to changes in flow regime.  More specifically, it performs the computations needed for duration and frequency of inundation from stream flooding necessary to document wetland hydrology.  These computations are useful for wetland determinations and wetland restoration planning and design.  It also performs calculations needed for planning and design of aquatic organism passage projects and determines appropriate planting zones for vegetation that is sensitive to differences in the frequency, duration, and timing of inundation.

HEC developed HEC-EFM for USACE use 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.

Special Instructions.  HEC-EFM 4.0 updates and replaces all previous versions of HEC-EFM.  This directive cancels, deletes, and replaces the previous user guide notification – User Guide (UG) 210-13-8 ENG:  Hydrologic Engineering Center – Ecosystems Functions Model (HEC-EFM) Version 3.0 NET Computer Program and Documentation, dated June 28, 2013.

The technical contacts, listed below, are evaluating this software for wider use as part of NRCS’s conservation mission.  If you successfully apply the software to NRCS programs, please reach out to the contacts and inform them of your experience.

Distribution.  USDA Office of the Chief Information Officer IT Resources tested and CCE certified HEC-EFM 4.0 for deployment to NRCS Information Service (ITS) supported workstations running Windows 10 x64 on August 7, 2020.  The project reference number is CRQ#3807904.

NRCS users are to obtain the HEC-EFM 4.0 through their IT support managers who can download and install the program.  NRCS makes no official printing or distribution of program documentation, but it can be downloaded from the USACE HEC-EFM Web site at

Filing Instructions.  Users wishing to retain paper copies of any of the HEC-EFM 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-EFM. However, general questions regarding this software may be directed to Maria Hrebik, Wetland Hydraulic Engineer at the Central National Technology Support Center at (817) 509-3296 or by email at ; or by contacting Jon Fripp, Stream Mechanics Engineer at the National Design, Construction, and Soil Mechanics Center at (817) 509-3771 or by email at    


Deputy Chief for Science and Technology                 
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