National Wetlands Inventory

National Wetlands Inventory
Name	National Wetlands Inventory
Formed	1974
Jurisdiction	United States
Parent agency	U.S. Fish and Wildlife Service
Headquarters	Arlington County, Virginia

National Wetlands Inventory is a program of the U.S. Fish and Wildlife Service that maps and characterizes wetland and deepwater habitats across the United States. It produces geospatial datasets, classification systems, and reports used by agencies such as the U.S. Geological Survey, Environmental Protection Agency, and state natural resource departments. The program informs conservation actions, regulatory processes, and scientific research involving species like the Whooping Crane, Wood Stork, and habitats such as the Everglades and Arctic National Wildlife Refuge.

History and development

The initiative began in 1974 within the U.S. Fish and Wildlife Service amid growing interest from entities like the National Academy of Sciences, the Bureau of Land Management, and the National Oceanic and Atmospheric Administration about declining wetland acreage after passage of laws including the Clean Water Act and the Endangered Species Act. Early efforts paralleled mapping programs such as the National Land Cover Database and collaborations with the U.S. Geological Survey and the National Aeronautics and Space Administration. Advances in aerial photography, digital cartography, and later partnerships with institutions like University of Minnesota, Duke University, and NOAA National Centers for Environmental Information enabled expansion of coverage from regional pilot projects to national-scale inventories. Policy drivers included recommendations from the National Research Council and implementation needs from agencies such as the Fish and Wildlife Coordination Act proponents and planners engaged with the Army Corps of Engineers.

Objectives and scope

The program’s primary objectives align with mandates from the U.S. Fish and Wildlife Service and federal conservation priorities set by administrations and agencies including the U.S. Department of the Interior, the National Oceanic and Atmospheric Administration, and state fish and wildlife agencies. Objectives include creating consistent wetland classification comparable to international frameworks like the Ramsar Convention, supporting species recovery plans for taxa such as the Bald Eagle and Piping Plover, and furnishing data for environmental review under statutes like the National Environmental Policy Act. Scope spans tidal and non-tidal wetlands, deepwater habitats, and associated riparian zones across the continental United States, Alaska, Hawaii, and territories addressed in coordination with the U.S. Territories and Freely Associated States frameworks.

Methods and data products

Mapping methods evolved from interpretation of visible-spectrum aerial photography to incorporation of multispectral satellite sensors deployed by Landsat, Sentinel-2, and airborne platforms used by partners at institutions such as Mississippi State University and University of Florida. Classification follows standardized categories influenced by models like the Cowardin classification system and integrates ancillary layers from the National Hydrography Dataset and the National Elevation Dataset. Data products include geospatial vector maps, raster derivatives, change-detection products used by the U.S. Geological Survey National Wetlands Research Center, and metadata catalogs compliant with the Federal Geographic Data Committee. Outputs support inventories for landscapes such as the Chesapeake Bay, Gulf Coast of the United States, and Great Lakes and are distributed to stakeholders including the National Park Service, Bureau of Land Management, and academic researchers.

Applications and uses

Agencies including the Environmental Protection Agency, Army Corps of Engineers, and state conservation offices use inventory products for permitting, mitigation planning, and compliance with statutes such as the Clean Water Act. Conservation NGOs like The Nature Conservancy and Ducks Unlimited rely on datasets for habitat prioritization, while academics at institutions such as Oregon State University and University of California, Davis employ them for studies of wetland loss, carbon sequestration, and climate resilience. Municipal planners in jurisdictions such as New York City and Los Angeles use wetland maps for floodplain management and green infrastructure projects alongside federal programs like the National Flood Insurance Program. Species recovery teams for taxa including the Saltmarsh Sparrow and California Ridgway's Rail integrate inventory data into recovery plans coordinated by the U.S. Fish and Wildlife Service.

Governance and partnerships

Governance is rooted in the U.S. Fish and Wildlife Service with funding and technical cooperation from entities such as the U.S. Geological Survey, the Environmental Protection Agency, and state natural resource agencies. Partnerships extend to academic centers including Duke University Wetland Center, nonprofit organizations such as Audubon Society, and interagency groups like the Federal Geographic Data Committee and the National Oceanic and Atmospheric Administration. International linkages occur through bodies like the Ramsar Convention and technical exchanges with agencies such as Environment and Climate Change Canada. Data stewardship follows federal standards overseen by the U.S. Department of the Interior and is coordinated with state agencies such as the California Department of Fish and Wildlife and Florida Fish and Wildlife Conservation Commission.

Limitations and criticisms

Critiques have targeted temporal resolution, with stakeholders such as the National Academy of Sciences and research teams from University of Georgia noting lags between imagery acquisition and product release compared to near-real-time needs cited by the Federal Emergency Management Agency. Spatial and thematic accuracy concerns were raised by state agencies and academics at Cornell University and Texas A&M University regarding small, ephemeral wetlands and urban wetlands obscured by canopy or infrastructure. Funding constraints from congressional appropriations and shifting priorities within the Department of the Interior and congressional committees have affected update frequency, prompting calls from conservation groups like The Nature Conservancy and Ducks Unlimited for enhanced integration with satellite-based monitoring systems such as Landsat 8 and commercial constellations. Efforts to address these criticisms include pilot projects with the U.S. Geological Survey and collaborations with the National Aeronautics and Space Administration to incorporate new remote sensing methods and machine learning by teams at institutions like Stanford University and Massachusetts Institute of Technology.

Category:Wetlands of the United States