Wetlands - National Wetlands Inventory

This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the conterminous United States. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). Certain wetland habitats are excluded from the National mapping program because of the limitations of aerial imagery as the primary data source used to detect wetlands. These habitats include seagrasses or submerged aquatic vegetation that are found in the intertidal and subtidal zones of estuaries and near shore coastal waters. Some deepwater reef communities (coral or tuberficid worm reefs) have also been excluded from the inventory. These habitats, because of their depth, go undetected by aerial imagery. By policy, the Service also excludes certain types of "farmed wetlands" as may be defined by the Food Security Act or that do not coincide with the Cowardin et al. definition. Contact the Service's Regional Wetland Coordinator for additional information on what types of farmed wetlands are included on wetland maps. Last Updated: 1992
Organization: State of Maryland
Organization URL: https://catalog.data.gov/organization/maryland
Last updated: 2026-06-09
Tags: chesapeake bay, coastal zone, department of natural resources, dnr, dynamic, hydr, hydrology, maryland, md, md imap, national wetlands inventory, nwi wetlands, u.s. fish and wildlife, usfw, vector, wetlands, wetlands of special state concern, wfs, wms