Wetlands provide a multitude of ecological, economic, and social benefits. They provide habitat for an array of fish, wildlife, and plants; recharge groundwater; reduce flooding; provide clean drinking water; offer food and fiber; and support cultural and recreational activities. Unfortunately, more than half of the nation’s wetlands have been lost since 1780, and wetland losses continue today. This highlights the urgent need for geospatial information on wetland extent, type, and change.
The National Wetlands Inventory (NWI) was established by the U.S. Fish and Wildlife Service (Service) to conduct a nationwide inventory of U.S. wetlands to provide biologists and others with information on the distribution and type of wetlands to aid conservation efforts. To do this, the NWI developed a wetland classification system that is now the official wetland classification system for the Service and the federal standard for wetland classification (61 FR 39465). The NWI also developed techniques for mapping and recording the inventory findings.
We rely on trained image analysts to identify and classify wetlands and deepwater habitats from aerial imagery. NWI started mapping wetlands at a small scale (1:250,000 map which covers an area the size of 128-1:24,000 USGS topographic maps or approximately 7,400 square miles). Eventually, large-scale (1:24Kscale) maps became the standard product delivered by NWI. As computerized mapping and geospatial technology evolved, NWI discontinued production of paper maps in favor of distributing data digitally through “mapping tools” where information can be viewed and downloaded. Today, the Service provides data through the Wetlands Mapper. GIS users can also access wetlands data through an online wetland mapping service or download data for various applications (maps data analyses, and reports).
NWI data support a multitude of applications for users throughout the country. Whether it is wetland conservation or restoration, emergency response, species habitat assessment and population modeling, infrastructure and recreation planning, or other types of decision support, NWI data have been a trusted resource for more than 40 years.
Learn how NWI data are used across the country.
Our mission is to provide the public with current geospatially referenced information on the status, extent, characteristics and functions of wetland, , deepwater, and related aquatic habitats in priority areas to promote the understanding, conservation, and restoration of these resources.