Natural Resources Conservation Service

United States Department of Agriculture

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Assessment Methods

The Wetland Team is in the process of developing a formal training/workshop on functional assessments, hydrogeomorphic (HGM) wetland classification, HGM functional assessments, development of rapid functional assessment models, use of data inputs into functional assessment to determine minimal effect, and use of data inputs and time/function calculations to determine appropriate minimal effect thresholds, mitigation requirements, and mitigation ratios.

Hydrogeomorphic Approach to Wetland Assessment

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Policy

Classification

Brinson, M. M. (1993). "A hydrogeomorphic classification for wetlands" (PDF, 5.5 MB) Technical Report WRP-DE-4, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. NTIS No. AD A270 053.
Smith, D. R., Ammann, A., Bartoldus, C., and Brinson, M. M. (1995). "An approach for assessing wetland functions using hydrogeomorphic classification, reference wetlands, and functional indices," (PDF, 3.10 MB) Technical Report WRP-DE-9, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS. NTIS No. AD A307 121.

National HGM Guidebooks

Riverine Wetlands (1995) (PDF, 1.1 MB)
Tidal Fringe Wetlands (1998) (PDF, 6.5 MB)

Regional Guidebooks

Draft California Vernal Pools HGM Guidebook (2009) (PDF, 7.2 MB)
Low Gradient, Riverine Wetlands in Western Kentucky (1999) (PDF, 1.5 MB)
Wet Pine Flats on Mineral Soils in the Atlantic & Gulf Coastal Plain (2002)(PDF, 40 MB)
Intermontane Prairie Pothole Wetlands in the Northern Rocky Mountains (2002)(PDF, 4.13 MB)
Low Gradient Riverine Wetlands in Western Tennessee (2002)(PDF, 5.34 MB)
Northwest Gulf of Mexico Tidal Fringe (2002)(PDF, 11.36 MB)
Selected Regional Wetland Classes, Yazoo Basin, Lower Mississippi River Alluvial Valley (2002)(PDF, 4.82 MB)
Northern Rocky Mountains (2002)(PDF, 7 MB)
Flats Wetlands in the Everglades (2002)(PDF, 13.04 MB)
Low Gradient, Backwater Riverine Wetlands in Peninsular Florida (2003)(PDF, 15.2 MB)
Rainwater Basin Depressional Wetlands in Nebraska (2004)(PDF, 6.76 MB)
Depressional Wetlands in Peninsular Florida (2004)(PDF, 4.09 MB)
Forested Wetlands in the Delta Region of Arkansas, Lower Mississippi River Alluvial Valley (2004)(PDF, 5.19 MB)
Forested Wetlands in the West Gulf Coastal Pain Region of Arkansas (2005)(PDF, 5.12 MB)
Prairie Potholes (2006)(PDF, 1.8 MB)
Depressional Wetlands in the Upper Des Plaines River Basin (2005)(PDF, 2.9 MB)
Wetland & Riparian Forests in the Ouachita Mountains and Crowley's Ridge Regions of Arkansas (2006)(PDF, 5.8 MB)
Headwater Slope Wetlands on the Mississippi and Alabama Coastal Plains (2007) (PDF, 5.9 MB)
Tidal Fringe Wetlands along the Mississippi and Alabama Gulf Coast (2007) (PDF, 6.9 MB)
Forested Wetlands and Riparian Areas in the Ozark Mountains Region of Arkansas (2008)
Forested Wetlands in the Arkansas Valley Region of Arkansas (2008) (PDF, 4.9 MB)
Forested Wetlands in Alluvial Valleys of East Texas (2010) (PDF, 8.9 MB)
High-gradient Ephemeral and Intermittent Headwater Streams in Western West Virginia and Eastern Kentucky (2010) (PDF, 4.0 MB)
Forested Wetlands in the Delta Region of Arkansas, Lower Mississippi River Alluvial Valley (2011) (PDF, 4.7 MB)
Headwater Slope Wetlands on the South Carolina Coastal Plain (2011) (PDF, 5.8 MB)
Forested Wetlands in the Mississippi Alluvial Valley (2013) (PDF, 2.9 MB)
Flat and Seasonally Inundated Depression Wetlands on the High Rim (2013) (PDF, 2.1 MB)
Forested Wetlands in Alluvial Valleys of the Coastal Plain of the Southeastern United States (2013) (PDF, 17.7 MB)
High-gradient Ephemeral and Intermittent Headwater Streams in Western West Virginia and Eastern Kentucky (2014) (PDF, 33.5 MB)

Other Assessment Methods

Technical Notes

Technical Note: 210-3: ENG-WTL- Soil Hydrodynamic Interpretations for Wetlands
Technical Note No. 4 Understanding Fluvial Systems: Wetlands, Streams, and Flood Plains
Hydrogeomorphic Wetland Classification System: An Overview and Modification to Better Meet the Needs of the Natural Resources Conservation Service (PDF, 122 KB)
This technical note provides a brief review of Brinson's original concepts and provides additional structure to the HGM wetland classification system.

State Interim Functional Assessment Procedures

The following are procedures for interim functional assessment are intended as examples for those in the process of developing their own procedures and to help bring about needed consistency between states and regions for interim functional assessment. These procedures are drafts and should not be referred to or cited as final.