The U.S. Fish and Wildlife Service (FWS) has produced wetland geospatial data for most of the country. While FWS posts its National Wetlands Inventory (NWI) data for public use via its “wetlands mapper,” it does not post data from special projects or ancillary data used to prepare the NWI data. The Virginia Tech’s Conservation Management Institute (CMI) has worked closely with the FWS Northeast Region to enhance NWI by adding more attributes (LLWW descriptors) to mapped wetlands in its geospatial database.
The expanded database, now called "NWI+ data," is used to better characterize wetlands and to predict wetland functions at the landscape-level. This database allows for more detailed characterization of wetlands across the landscape and makes it possible to predict wetland functions at the landscape-level. NWI+ data may be further expanded to include other geospatial data such as areas that were not detected as wetlands by NWI but may support wetlands due to soil mapping (“P-wet areas”) and potential wetland restoration sites. These special projects have produced geospatial data, maps and technical reports on study findings for specific watersheds or in some cases, states.
To use the NWI+ database, relationships between wetland properties in the database and wetland functions had to be developed. The Northeast Regional Wetland Coordinator, working with several groups of scientists and wetland practitioners from the eastern U.S. on various NWI+ applications, developed these relationships for what now are eleven functions of interest: surface water detention (for nontidal wetlands only), coastal storm surge detention, streamflow maintenance, nutrient transformation, retention of sediment and other particulates, carbon sequestration, bank and shoreline stabilization, provision of fish and aquatic invertebrate habitat, provision of waterfowl and waterbird habitat, provision of habitat for other wildlife, and provision of unique, uncommon, or highly diverse plant communities.
Development of NWI+ databases is not a standard NWI product. It has been applied to pilot study areas and to areas of interest in some regions. Applications are particularly widespread in the Northeast where the technique evolved. Statewide NWI+ databases have been created for Delaware and Connecticut, while statewide databases for Massachusetts, Rhode Island, and New Jersey should be completed by the end of 2013. Completed NWI+ datasets may be viewed online through the NWI+ Web Mapper. Several states have produced similar data for select watersheds or regions, including Georgia, Michigan and Montana (see the State Data links for their data), while other states are conducting pilot studies or statewide applications (e.g., Minnesota, New Mexico, Oregon, and Wisconsin).