This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). The National Wetlands Inventory - Version 2, Surface Waters and Wetlands Inventory was derived by retaining the wetland and deepwater polygons that compose the NWI digital wetlands spatial data layer and reintroducing any linear wetland or surface water features that were orphaned from the original NWI hard copy maps by converting them to narrow polygonal features. Additionally, the data are supplemented with hydrography data, buffered to become polygonal features, as a secondary source for any single-line stream features not mapped by the NWI and to complete segmented connections. Wetland mapping conducted in WA, OR, CA, NV and ID after 2012 and most other projects mapped after 2015 were mapped to include all surface water features and are not derived data. The linear hydrography dataset used to derive Version 2 was the U.S. Geological Survey's National Hydrography Dataset (NHD). Specific information on the NHD version used to derive Version 2 and where Version 2 was mapped can be found in the 'comments' field of the Wetlands_Project_Metadata feature class. 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. This dataset should be used in conjunction with the Wetlands_Project_Metadata layer, which contains project specific wetlands mapping procedures and information on dates, scales and emulsion of imagery used to map the wetlands within specific project boundaries.

Note that due to the quantity and complexity of the data there is scale dependent rendering enabled. The vector data only draws when zoomed in to 1:250,000 map scale or larger. To view the wetlands data at a smaller scale utilize the Wetlands Raster service (https://www.fws.gov/wetlandsmapservice/rest/services/Wetlands_Raster/ImageServer) to display generalized wetlands at all scales.. For specific questions or assistance please email wetlands_team@fws.gov.For more information visit: https://www.fws.gov/wetlands/index.htmlView Wetlands Data on the Wetlands Mapper at: https://www.fws.gov/wetlands/Data/Mapper.htmlWetlands Web Services are available at: https://www.fws.gov/wetlands/Data/Web-Map-Services.htmlWetlands Data available as a KML at: https://www.fws.gov/wetlands/Data/Google-Earth.htmlWetlands Data Downloads available at: https://www.fws.gov/wetlands/Data/Data-Download.htmlWetland Data Standards available at: https://www.fws.gov/wetlands/Data/Data-Standards.htmlWetland Codes available at: https://www.fws.gov/wetlands/Data/Wetland-Codes.htm

September 2025

Project Level MetadataWetland mapping is conducted in defined geographic areas called projects. Imagery is used as the base information to define the type and location of each wetland. The scale, type and date of imagery used in a project is provided in a pop-up window when a wetland polygon is selected on the Wetlands Mapper. Investigators that complete a wetland mapping project record information on the source imagery, collateral data, inventory method, data limitations, geographic features, landforms, wetland types and other specifics in a project metadata document.This project level metadata can be found by selecting a wetland polygon on the Wetlands Mapper and then clicking on the link next to ‘Project Metadata’ in the pop-up window. Note: Not all areas have a Project Metadata document. Historic Wetlands Map Information MetadataInformation about the wetland types, vegetation, regional and temporal conditions and geographic features are captured in a historic map document. This document is specific to a geographic area and can be accessed by selecting a wetland polygon on the Wetlands Mapper and then clicking on the link next to ‘Historic Map Info’ in the pop-up window. Note: Not all areas have a Historic Wetlands Map Information document.Unvegetated coastal wetlands (see the coastal wetlands definition) containing silt, clay, or sand that are subject to inundation by wind-driven water level fluctuations and may be covered by algal mats (blue - green algae i.e.cyanobacteria). Tidal sand and mud flats protect shorelines by diffusing wave energy, provide feeding grounds for coastal shorebirds, fish, and invertebrates and, when algal mats are present, serve an important role in nutrient cycling.This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). The National Wetlands Inventory - Version 2, Surface Waters and Wetlands Inventory was derived by retaining the wetland and deepwater polygons that compose the NWI digital wetlands spatial data layer and reintroducing any linear wetland or surface water features that were orphaned from the original NWI hard copy maps by converting them to narrow polygonal features. Additionally, the data are supplemented with hydrography data, buffered to become polygonal features, as a secondary source for any single-line stream features not mapped by the NWI and to complete segmented connections. Wetland mapping conducted in WA, OR, CA, NV and ID after 2012 and most other projects mapped after 2015 were mapped to include all surface water features and are not derived data. The linear hydrography dataset used to derive Version 2 was the U.S. Geological Survey's National Hydrography Dataset (NHD). Specific information on the NHD version used to derive Version 2 and where Version 2 was mapped can be found in the 'comments' field of the Wetlands_Project_Metadata feature class. 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. This dataset should be used in conjunction with the Wetlands_Project_Metadata layer, which contains project specific wetlands mapping procedures and information on dates, scales and emulsion of imagery used to map the wetlands within specific project boundaries.Field Definitions:For field definitions contact the US Fish and Wildlife Service

This data set is a Status Map that identifies the location of wetland data and no data areas. The wetland data itself represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Trust Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). Certain wetland habitats may be excluded 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.The U.S. Fish and Wildlife Service (Service) is the principal Federal agency that provides information to the public on the extent and status of the Nation's wetlands. The Service's strategic plan for our vast national wetland data holdings is focused on the development, updating, and dissemination of wetlands data and information to Service resource managers and the public. The development of the Wetlands Master Geodatabase is in direct response to the need to integrate digital map data with other resource information to produce timely and relevant management and decision support tools.For more information visit: https://www.fws.gov/wetlands/index.htmlView Wetlands Data on the Wetlands Mapper at: https://www.fws.gov/wetlands/Data/Mapper.htmlWetlands Web Services are available at: https://www.fws.gov/wetlands/Data/Web-Map-Services.htmlWetlands Data available as a KML at: https://www.fws.gov/wetlands/Data/Google-Earth.htmlWetlands Data Downloads available at: https://www.fws.gov/wetlands/Data/Data-Download.htmlWetland Data Standards available at: https://www.fws.gov/wetlands/Data/Data-Standards.html

National Wetland Inventory (NWI) data for Minnesota provide information on the location, extent, and type of Minnesota wetlands. Natural resource managers use NWI data to improve the management, protection, and restoration of wetlands. Wetlands provide many ecological benefits including habitat for fish and wildlife, reducing floods, recharging, improving water quality, and supporting recreation.

These data were updated through a decade-long, multi-agency collaborative effort under leadership of the Minnesota Department of Natural Resources (MNDNR). Major funding was provided by the Environmental and Natural Resources Trust Fund.

This is the first statewide update of the NWI for Minnesota since the original inventory in the mid-1980s. The work was completed in phases by dividing the state into five project areas. Those project areas have all been edgematched into a final seamless statewide dataset.

Ducks Unlimited (Ann Arbor, MI) and St. Mary’s University Geospatial Services (Winona, MN) conducted the wetland mapping and classification under contract to the MNDNR. The Remote Sensing and Geospatial Analysis Laboratory at the University of Minnesota provided support for methods development and field validation. The DNR Resource Assessment Office provided additional support for data processing, field checking, and quality control review.

The updated NWI data delineate and classify wetlands according to the system developed by Cowardin et al. (1979), which is consistent with the original NWI. The updated data also contain a simplified plant community classification (SPCC) and a simplified hydrogeomorphic (HGM) classification. Quality assurance of the data included visual inspection, automated checks for attribute validity and topologic consistency, as well as a formal accuracy assessment based on an independent field verified data set. Further details on the methods employed can be found in the technical procedures document for this project located on the project website (http://www.dnr.state.mn.us/eco/wetlands/nwi_proj.html ).

DOWNLOAD NOTE: NWI data are only provided in either ESRI File Geodatabase or OGC GeoPackage formats. A Shapefile is not available because the size of the NWI dataset exceeds the limit for that format. If you are unable to use the File Geodatabase or GeoPackage, you can view data through Wetland Finder, an interactive mapping application on the DNR’s website (https://arcgis.dnr.state.mn.us/ewr/wetlandfinder ).

SYMBOLOGY NOTE: The ESRI File Geodatabase download includes four layer files that symbolize the data using four different wetland classification systems. The symbology layer files for the Cowardin class and the simplified HGM class are grouped into a smaller number of classes than the full elaborated classifications. Detail is available in the Minnesota Wetland Inventory User Guide and Summary Statistics report (https://files.dnr.state.mn.us/eco/wetlands/nwi-user-guide.pdf ). The layer files for these data have been set up to restrict drawing of the data when zoomed out beyond 1:250,000 scale. This is, in part, to prevent problems with slow performance with this large dataset.

This is a MD iMAP hosted service layer. Find more information at http://imap.maryland.gov. 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: Feature Service Layer Link: https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Wetlands/MapServer ADDITIONAL LICENSE TERMS: The Spatial Data and the information therein (collectively the ""Data"") is provided "as is" without warranty of any kind either expressed implied or statutory. The user assumes the entire risk as to quality and performance of the Data. No guarantee of accuracy is granted nor is any responsibility for reliance thereon assumed. In no event shall the State of Maryland be liable for direct indirect incidental consequential or special damages of any kind. The State of Maryland does not accept liability for any damages or misrepresentation caused by inaccuracies in the Data or as a result to changes to the Data nor is there responsibility assumed to maintain the Data in any manner or form. The Data can be freely distributed as long as the metadata entry is not modified or deleted. Any data derived from the Data must acknowledge the State of Maryland in the metadata.

NWI digital data files are records of wetlands location and classification as defined by the U.S. Fish & Wildlife Service. This dataset is one of a series available in 7.5 minute by 7.5 minute blocks containing ground planimetric coordinates of wetlands point, line, and area features and wetlands attributes. When completed, the series will provide coverage for all of the contiguous United States, Hawaii, Alaska, and U.S. protectorates in the Pacific and Caribbean. The digital data as well as the hard copy maps that were used as the source for the digital data are produced and distributed by the U.S. Fish & Wildlife Service's National Wetlands Inventory project. The data provide consultants, planners, and resource managers with information on wetland location and type. The data were collected to meet U.S. Fish & Wildlife Service's mandate to map the wetland and deep-water habitats of the United States.The full Kansas geospatial catalog is administered by the Kansas Data Access & Support Center (DASC) and can be found at the following URL: https://hub.kansasgis.org/

This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. 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.

The National Wetlands Inventory (NWI) dataset was downloaded from the US Fish and Wildlife Service website at https://www.fws.gov/wetlands/Data/State-Downloads.html on 05/04/2021. Metadata derives from original NWI database and updated to reflect the date of download. According to website, this layer was updated last October 1st, 2020. This is a clip of all wetlands features within the Westchester County boundary minus all riverines, Long Island Sound, and the Hudson River.This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). The National Wetlands Inventory - Version 2, Surface Waters and Wetlands Inventory was derived by retaining the wetland and deepwater polygons that compose the NWI digital wetlands spatial data layer and reintroducing any linear wetland or surface water features that were orphaned from the original NWI hard copy maps by converting them to narrow polygonal features. Additionally, the data are supplemented with hydrography data, buffered to become polygonal features, as a secondary source for any single-line stream features not mapped by the NWI and to complete segmented connections. Wetland mapping conducted in WA, OR, CA, NV and ID after 2012 and most other projects mapped after 2015 were mapped to include all surface water features and are not derived data. The linear hydrography dataset used to derive Version 2 was the U.S. Geological Survey's National Hydrography Dataset (NHD). Specific information on the NHD version used to derive Version 2 and where Version 2 was mapped can be found in the 'comments' field of the Wetlands_Project_Metadata feature class. 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. This dataset should be used in conjunction with the Wetlands_Project_Metadata layer, which contains project specific wetlands mapping procedures and information on dates, scales and emulsion of imagery used to map the wetlands within specific project boundaries.

In 2016 NYC Parks contracted with the UVM Spatial Analysis Lab to use modern remote sensing and object-based image analysis to create a new wetlands map for New York City. Data inputs include Light Detection and Ranging Data, State and Federal Wetland Inventories, soils, and field data. Because the map was conservative in its wetlands predictions, NYC Parks staff improved the map through a series of desktop and field verification efforts. From June to November 2020, NYC Parks staff field verified the majority of wetlands on NYC Parks' property. The map will be opportunistically updated depending on available field information and delineations. Another dedicated field verification effort has not been planned. As of June 2021, no subsequent updates to the data are scheduled. Original field names were updated to field names that are easier to understand. This dataset was developed to increase awareness regarding the location and extent of wetlands to promote restoration and conservation in New York City. This map does not supersede U.S. Fish and Wildlife Service National Wetlands Inventory (NWI) and New York State Department of Environmental Conservation (NYSDEC) wetlands maps and has no jurisdictional authority. It should be used alongside NWI and NYSDEC datasets as a resource for identifying likely locations of wetlands in New York City. Mapped features vary in the confidence of their verification status, ranging from "Unverified" (meaning the feature exists in its original remotely mapped form and has not been ground truthed) to "Verified - Wetland Delineation" (meaning the boundaries and type of wetland have been verified during an official wetland delineation). Because of the rapid nature of the protocol and the scale of data collection, this product is not a subsitute for on-site investigations and field delineations. The dataset also includes broad classifications for each wetland type, e.g. estuarine, emergent wetland, forested wetland, shrub/scrub wetland, or water. Cowardin classifcations were not used given rapid verfication methods. The accuracy of the wetlands map has improved over time as a result of the verification process. Fields were added over time as necessitated by the workflow and values were updated with information, either from the field verifications, delineation reports, or desktop analysis. OBJECTID, Shape, Class_Name_Final, Verification_Status, Create_Date, Last_Edited_Date, Verification_Status_Year, SHAPE_Length, SHAPE_Area https://www.nycgovparks.org/greening/natural-resources-group Data Dictionary: https://docs.google.com/spreadsheets/d/1a45qCho45MV-AuOlGxyaRp0cg3cRFKw4lAYBIaU3zi4/edit#gid=260500519 Map: https://data.cityofnewyork.us/dataset/NYC-Wetlands/7piy-bhr9

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

This data set represents the extent, status, and location of mapping projects for the National Wetlands Inventory Version 2, Surface Waters and Wetlands. Each project polygon contains information on the type and date, scales and emulsion of imagery used to map the wetlands within specific project boundaries, and a link to a document about specific mapping techniques and habitat information for that project.See full metadataFeature servce also available.

Wetland area features mapped as part of the National Wetlands Inventory (NWI). The National Wetlands Inventory is a national program sponsored by the US Fish and Wildlife Service (USFWS). The NWI database was funded jointly between the USFWS and the State. The base data was developed through interpretation of National Aerial Photography Program (NAPP) imagery (approx. 1:50,000 scale, typically color-infrared) in conjunction with limited field verification studies. Ancillary data sources, particularly USGS Quadrangle Maps and soil surveys, were also used in the interpretation process. After interpreting the aerial photographs, delineations were transferred to a 1:24,000 scale orthogonal base, digitized, and coded in conformance to the USFWS classification scheme and structured into a DLG format. The original interpretation/automation effort was performed under contract by GEONIX-MARTEL of St. Petersburg, FL. The data were delivered to LMIC, who converted it into an ARC/INFO format, and performed some additional processing to prepare it for distribution. Librarian data were then appended and converted to ArcGIS File Geodatabase feature classes by DNR Staff (2009).

For the most recent National Wetlends Inventory data for Minnesota, please use https://gisdata.mn.gov/dataset/water-nat-wetlands-inv-2009-2014

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.This is a MD iMAP hosted service layer. Find more information at https://imap.maryland.gov.Feature Service Layer Link:https://mdgeodata.md.gov/imap/rest/services/Hydrology/MD_Wetlands/MapServer/2

A feature service is also available here: https://gis.ducks.org/datasets/duinc::minnesota-restorable-wetlandsHISTORY: In October 2000, a Restorable Wetlands Working Group formed to begin mapping all of the restorable wetlands in the glaciated tallgrass Prairie Pothole Region of Minnesota and Iowa. Today, fewer than 10% of the original wetlands - once of unparalleled importance to continental waterbird populations - are left in existence. Fortunately, wetlands once drained for agriculture may be restored to many of their historic functions. Restoration of multiple wetland functions is of utmost effectiveness when focused at priority restoration landscapes, therefore data on the historic distribution of wetlands is an integral part of developing strategic regional habitat restoration plans.Opportunistic wetland restorations often fail to attain out expectations for wetland function. Nevertheless, between $70 - $100,000,000 are spent annually in Minnesota for wetland restoration. A strategic plan for wetland restoration can make these expenditures more effective; however, a strategic wetland restoration plan requires a priori information on the distribution and extent of restorable wetlands. The collective goal of the Restorable Wetlands Working Group is the eventual development of a set of multi-agency decision support tools that collectively comprise a comprehensive environmental management plan for wetlands - all based on the same base data layers and developed in joint consultation. An effort is underway to delineate restorable wetlands in all intensively farmed areas of MN and IA.A pilot project determined the best technique to map drained wetlands in agricultural landscapes was photointerpretation. This pilot project evaluated the accuracy of three potential delineation techniques: digital hydric soils databases, digital elevation models, and manual stereoscopic photointerpretation on high-altitude color infrared aerial photographs. The project covered nearly 4,000 square miles of different land forms and wetland characteristics. After mapping was completed, some 1,500 drained wetlands were observed in the field to assess the accuracy of each technique. Only photointerpretation provided reliable results.One area that fell into the pilot study was the Okabena quadrangle in east-central Jackson County in Minnesota. Okabena vividly illustrates the potential of humans to alter the natural landscape. While Okabena historically encompassed more than 8,940 acres of depressional wetland - 27% of the total area of Okabena - after nearly 100 years of agricultural drainage only 1,280 acres of those original wetlands remain, representing an 86% reduction. When empirical models used to estimate duck pairs on individual wetlands are applied to the change from historic to current wetland habitat within Okabena, they estimate a 92% reduction in the habitat potential for common dabbling duck species.The Okabena quadrangle's wetland density once exceeded that of most of the remaining U.S. Prairie Pothole Region. Without strong incentives for wetland conservation and effective methods to delineate high-priority landscapes for restoration, the Okabena quadrangle foretells one possible future for much of the mixed-grass Prairie Pothole Region further west.The Final Status map was completed in 2012.Contact Information:Rex JohnsonUnited States Fish and Wildlife Service21932 State Highway 210Fergus Falls, MN 56537(218) 736-0606rex_johnson@fws.govPhotointerpretationNational Aerial Photography Program (NAPP) (1:40,000 scale) color infrared (CIR) photographs acquired in April and May, 1991 and 1992, were viewed in stereo pairs at 5X magnification using a Cartographic Engineering stereoscope. A Mylar overlay was mounted on one photo of each stereo pair and a rectangular work area was delineated on the overlay comprising one-quarter of a USGS 7.5 min topographic quadrangle. A minimum of 4 fiduciary marks were placed on the overlay to enable geographic rectification of digital data covering the work area. One fiduciary mark was placed at the corner of the US Geological Survey (USGS) 7.5 min quadrangle and others at conspicuous road intersections near the other 3 corners of the work area. Drained depressional wetlands were delineated on the Mylar overlay within the work area using a 6X0 (.13 mm diameter) rapidograph pen and indelible ink. Collateral data was consulted during the delineation process. These data consisted of published county soil surveys and descriptions of hydric soils, USDA Farm Service Agency compliance slides (aerial 35 mm slides) acquired in 1993 (immediately after a period of intense precipitation), USGS 7.5 min topographic maps, and National Wetlands Inventory (NWI) maps. Black and white NAPP photographs (1:40,000 scale) acquired primarily in August and September, 1996, were reviewed and rejected as collateral data because they were acquired under dry conditions.Other specific photointerpretation protocols were:1. All drained depressional wetlands, regardless of size, were delineated.2. NWI-delineated wetlands with a Ad@ (partially drained) modifier in the classification code were not delineated unless the original delineation failed to encompass the complete historic wetland area.3. NWI-delineated wetlands that did not contain a Ad@ modifier in the classification code were delineated if the original delineation did not include the entire historic wetland area.4. Wetlands identified on NWI maps which did not exhibit wetland characteristics (i.e. hydrology, hydrophytes, etc) on new (1992) CIR photography were delineated even if no evidence of drainage was apparent.5. Wetlands not delineated on NWI maps, and in cropland, were delineated.6. Wetlands not delineated on NWI maps, and in grassland, were not delineated unless evidence of drainage was observed on the aerial photo.7. Wetlands not delineated on NWI maps, and in trees, were not delineated.Tolerances:Scanned line data were converted to a polygon using a 6 m fuzzy tolerance. Open polygons were manually closed and cleaned with a 1.2 m fuzzy tolerance which was used for all subsequent data processing.Datafile Description and Attribute Definitions[County_Name]_nwx - National Wetlands Inventory delineations (see https://www.fws.gov/program/national-wetlands-inventory/wetlands-mapper for NWI delineation standards). Note: Wetland classifications in these data often differ slightly from the original NWI classification. NWI wetland classifications were simplified for these data by removing mixed classes and multiple special modifiers, and by standardizing letter case. In each case of mixed classes and multiple special modifiers, the first class or special modifier was retained.AttributesRestorable - 0 = Islands and the Universal Polygon100 = Restorable depressional wetland delineated using protocols described aboveCounty Name – The name of the county in which the center of the polygon is located.State Name – The name of the state.FIPS – The FIPS code.

This data set represents the extent, approximate location and type of wetlands and deepwater habitats in the United States and its Territories. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin et al. (1979). The National Wetlands Inventory - Version 2, Surface Waters and Wetlands Inventory was derived by retaining the wetland and deepwater polygons that compose the NWI digital wetlands spatial data layer and reintroducing any linear wetland or surface water features that were orphaned from the original NWI hard copy maps by converting them to narrow polygonal features. Additionally, the data are supplemented with hydrography data, buffered to become polygonal features, as a secondary source for any single-line stream features not mapped by the NWI and to complete segmented connections. Wetland mapping conducted in WA, OR, CA, NV and ID after 2012 and most other projects mapped after 2015 were mapped to include all surface water features and are not derived data. The linear hydrography dataset used to derive Version 2 was the U.S. Geological Survey's National Hydrography Dataset (NHD). Specific information on the NHD version used to derive Version 2 and where Version 2 was mapped can be found in the 'comments' field of the Wetlands_Project_Metadata feature class. 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. This dataset should be used in conjunction with the Wetlands_Project_Metadata layer, which contains project specific wetlands mapping procedures and information on dates, scales and emulsion of imagery used to map the wetlands within specific project boundaries.

Digital wetlands data are intended for use with base maps and digital aerial photography at a scale of 1:12,000 or smaller. Due to the scale, the primary intended use is for regional and watershed data display and analysis, rather than specific project data analysis. The map products were neither designed nor intended to represent legal or regulatory products. Due to the quantity and complexity of the wetlands data the wetlands only display at 1:250,000 scale and greater. For wetland information visit: https://www.fws.gov/program/national-wetlands-inventoryView Dataset on the Gateway

This hosted feature layer has been published in RI State Plane Feet NAD 83.This data set represents the extent, approximate location and type of wetlands and deepwater habitats in Rhode Island. 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.

(Link to Metadata) VCGI downloaded NWI quads from the US FWS web site and reprojected to VCS NAD83. NWI digital data files are records of wetlands location and classification as developed by the U.S. Fish & Wildlife Service. This dataset is one of a series available in 7.5 minute by 7.5 minute blocks containing ground planimetric coordinates of wetlands point, line, and polygon features and wetlands attributes. When completed, the series will provide coverage for all of the contiguous United States, Hawaii, Alaska, and U.S. protectorates in the Pacific and Caribbean. Coverage includes both digital data and hardcopy maps. The NWI maps do not show all wetlands since the maps are derived from aerial photointerpretation with varying limitations due to scale, photo quality, inventory techniques, and other factors. Consequently, the maps tend to show wetlands that are readily photointerpreted given consideration of photo and map scale. In general, the older NWI maps prepared from 1970s-era black and white photography (1:80,000 scale) tend to be very conservative, with many forested and drier-end emergent wetlands (e.g., wet meadows) not mapped. Maps derived from color infrared photography tend to yield more accurate results except when this photography was captured during a dry year, making wetland identification equally difficult. Proper use of NWI maps therefore requires knowledge of the inherent limitations of this mapping. It is suggested that users also consult other information to aid in wetland detection, such as U.S. Department of Agriculture soil survey reports and other wetland maps that may have been produced by state and local governments, and not rely solely on NWI maps. See section on "Completeness_Report" for more information. Also see an article in the National Wetlands Newsletter (March-April 1997; Vol. 19/2, pp. 5-12) entitled "NWI Maps: What They Tell Us" (a free copy of this article can be ordered from U.S. Fish and Wildlife Service, ES-NWI, 300 Westgate Center Drive, Hadley, MA 01035, telephone, 413-253-8620).