Scientific Investigations Report 2005-5244
A wetland classification system was designed for Mt. Desert Island, Maine, to help categorize the large number of wetlands (over 1,200 mapped units) as an aid to understanding their hydrologic functions. The classification system, developed by the U.S. Geological Survey (USGS), in cooperation with the National Park Service, uses a modified hydrogeomorphic (HGM) approach, and assigns categories based on position in the landscape, soils and surficial geologic setting, and source of water. A dichotomous key was developed to determine a preliminary HGM classification of wetlands on the island. This key is designed for use with USGS topographic maps and 1:24,000 geographic information system (GIS) coverages as an aid to the classification, but may also be used with field data.
Hydrologic data collected from a wetland monitoring study were used to determine whether the preliminary classification of individual wetlands using the HGM approach yielded classes that were consistent with actual hydroperiod data. Preliminary HGM classifications of the 20 wetlands in the monitoring study were consistent with the field hydroperiod data. The modified HGM classification approach appears robust, although the method apparently works somewhat better with undisturbed wetlands than with disturbed wetlands. This wetland classification system could be applied to other hydrogeologically similar areas of northern New England.
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Purpose and Scope
Description of Study Area
Approach: Designing a Hydrogeomorphic Classification System
Assigning and Testing HGM Subclasses
Classification System for Wetlands on Mt. Desert Island
Preliminary HGM Classification System
Depressional–No Ground-Water Input
Mineral Soil Flats
Organic Soil Flats
Application of Classification System
Dichotomous Key for the Identification of Wetland Subclasses
Expected Hydroperiod Characteristics
Example of Classifying Wetlands: A Test Case in Acadia National Park
Data Collection for the Test Wetlands
Hydrogeomorphic Classification without Hydroperiod Data
Evaluation of Preliminary Hydrogeomorphic Classification Using Hydroperiod Data
Comparison of Disturbed and Undisturbed Wetlands
Summary and Conclusions
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For further information, contact:
Robert Lent, Director
U.S. Geological Survey,
Maine Water Science Center
196 Whitten Road
Augusta, Maine 04330
Please visit our Web site at: me.water.usgs.gov/.