Classification of Wetlands and Deepwater Habitats in the United States

Work on the development of this standard began in 1974, when the U.S. Fish and Wildlife Service directed its (then) Office of Biological Services to design and conduct a National inventory of wetlands. Although the purpose of an earlier (1954) inventory was to assess the amount and types of waterfowl habitat, the scope of the 1974 inventory was considerably broader. It's function was to provide basic data on the characteristics and extent of the Nation's wetlands and deepwater habitats to facilitate the management of those areas on a sound, multiple-use basis.

Subsequent field testing of a proposed classification system for the National inventory resulted in the publication of a national wetland classification system in 1979 )Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. Classification of Wetlands and Deepwater Habitats of the United States. U.S. U.S. Fish and Wildlife Service FWS/OBS - 79/31. 131 pp.) commonly referred to as the "Cowardin system." The classification system was developed by wetland ecologists with the assistance of many private individuals and organizations and local, State, and Federal agencies. An operational draft was published in October, 1977, and a notice of intent to adopt the system for all pertinent Fish and Wildlife Service activities was published in the Federal Register on December 12, 1977 (42 FR 62432).

The Wetlands Subcommittee of the Federal Geographic Data Committee reviewed the publication and then recommended that the "Cowardin system" be selected as the standard for wetlands mapping and inventory. The public was informed of this recommendation in a Federal Register notice published July 6, 1995 (60 FR 35217). Comments received from the public did not provide substantial new information that altered the original intent of the Subcommittee. This was published in the Federal Register on July 29, 1996 (61 FR 39465).

a. Reed, P.B., Jr. 1988. National list of plant species that occur in wetlands: national summary. U.S. Fish and Wildlife Service Biological Report 88(24) 244 pp. (And its regional updates.

b. National Technical Committee for Hydric Soils. 1991. Hydric soils of the United States. U.S. Department of Agriculture Soil Conservation Service, Miscellaneous Publication 1491. n.p.

a. provide a nationally consistent definition of wetlands and deepwater habitats for mapping and inventory purposes;

b. describe ecological units that have certain homogeneous natural attributes;

c. arrange those units in a system that will aid decisions about resource management;

d. furnish units for inventory and mapping;

e. ensure that data from widely differing regions of the country are collected and can be interpreted similarly; and,

f. move toward a system that allows communication about wetlands and their features in a National context. Doing so enhances the ability of all agencies and individuals to interpolate and extrapolate wetland resource data, wetland loss and gain data, and restoration efforts in the same semantic and ecological context.

The standard is intended for use in the acquisition of government data involving the extent, classification, and inventory of wetlands and deepwater habitats in the United States and its territories.

Adoption of the standard will not change the current status of National Wetlands Inventory maps produced by the U.S. Fish and Wildlife Service. Application of the standard is not regulatory. As the disclaimer on each NWI map states, "Federal, State, and local regulatory agencies with jurisdiction over wetlands may define and describe wetlands in a different manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to define the limits of proprietary jurisdiction of any Federal, State, or local government or to establish the geographical scope of the regulatory programs of government agencies."

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