This quick start guide is designed to demonstrate the process used to apply HEC-EFM and to highlight some features of the software.  Everything covered in this document and all features active in the software have been tested extensively, but there is still the potential for undetected problems to surface.  If a bug or suspect behavior is noted, please refer to HEC’s website (www.hec.usace.army.mil/software/HEC-EFM/BugReporting/) for guidance on bug reporting.

To summarize, HEC-EFM is designed to help study teams determine ecosystem responses to changes in the flow regime of a river or connected wetland. HEC-EFM analyses involve: 1) statistical analyses of relationships between hydrology and ecology, 2) hydraulic modeling, and 3) use of GIS. Through this process, study teams define existing ecologic conditions, highlight promising restoration sites, and assess alternatives according to predicted ecosystem changes.

The spatial products of this process are commonly managed and analyzed with a tool called HEC-GeoEFM.  Development of HEC-GeoEFM is a partnered effort between HEC and Environmental Systems Research Institute, Inc. (ESRI).  Version 1.0 was released in June 2011.  It contains a suite of features (habitat calculators, patch tools, etc.) that help modelers perform the spatial computations typically used in HEC-EFM applications. 

HEC-EFM has many strengths, most notably it 1) is capable of testing change for many ecological relationships and management scenarios, 2) links ecology with established hydrologic, hydraulic, and GIS tools, and 3) can be applied quickly, inexpensively, and can incorporate expert knowledge.  HEC-EFM is a generic software tool in the sense that it is applicable to a wide range of riverine and wetland ecosystems, water management concerns, and restoration projects.

HEC-EFM also has key limitations, including: 1) uses only daily data, 2) no explicit tracking of inter-year dynamics, and 3) outputs are often proxies or indicators for more tangible ecological attributes such as species population levels and ecosystem services. 

New features are being added to HEC-EFM, HEC-EFM Plotter, and HEC-GeoEFM that advance their collective ability to analyze flow regimes and to map and assess habitats.  Additionally, long-term development will enable HEC-EFM to simulate ecosystems in time and space and to animate results.  This spatial and temporal linking promises to address the limitations noted above and is being implemented in parallel to the software's current capabilities.

This scalability, where applications of these software can be statistical analyses of flow regimes or also map habitat or simulate population dynamics, allows modeling to be customized per the needs of different projects and offers opportunities to engage study teams and stakeholders by producing results at each level of application.

HEC-EFM and HEC-GeoEFM are certified for national use by Headquarters of the U.S. Army Corps of Engineers as recommended by the Corps’ Ecosystem Center of Expertise.  Model certification is a corporate determination that a model is a technically, theoretically, and functionally sound and can be applied during the Corps planning process for purposes consistent with the model’s design and limitations.  HEC-EFM has many possible applications.  The most common are ecosystem restoration planning, water management decision-making, benefit and impact analyses related to water levels, and natural resources management considerations.