| Abstract
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The latest National Wetlands Inventory (NWI) data for Montana is available at http://mtnhp.org/wetlands. These layers contain mostly historic data, digitized from hardcopy maps, that were available from the State Library in 2004-2006. This data is provided by the State Library as a supplement to current NWI data, to provide some wetland information for areas that are not covered by current mapping. The majority of the information in this metadata record came from the U.S. Fish and Wildlife Service before 2004 and may contain web links that are out of date.Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water.For purposes of this classification wetlands must have one or more of the following three attributes:
1) at least periodically, the land supports predominantly hydrophytes;
2) the substrate is predominantly undrained hydric soil; and
3) the substrate is non-soil and is saturated with water or covered by shallow water at some time during the growing season of each year.NWI digital data files are records of wetlands location and classification as developed by the U.S. Fish and Wildlife Service. This dataset contains ground planimetric coordinates of wetlands point, line, and polygon features and wetlands attributes.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.This data set represents the extent, approximate location and type of wetlands and deepwater habitats in Montana. These data delineate the areal extent of wetlands and surface waters as defined by Cowardin, L.M., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish Wildlife Service. 103 pp.By policy, the Inventory 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 U.S. Fish and Wildlife Service's Regional Wetland Coordinator for additional information on what types of farmed wetlands are included on wetland maps.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.
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| Purpose
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This data is provided by the State Library as a supplement to current NWI data, to provide some wetland information for areas that are not covered by current mapping.
The data provide consultants, planners, and resource managers with information on wetland location and type. The data were collected to meet U.S. Fish and Wildlife Service's mandate to map the wetland and deepwater habitats of the United States. The purpose of this survey was not to map all wetlands and deepwater habitats of the United States, but rather to use aerial photointerpretation techniques to produce thematic maps that show, in most cases, the larger ones and types that can be identified by such techniques. The objective was to provide better geospatial information on wetlands than found on the U.S. Geological Survey topographic maps.
It was not the intent of the NWI to produce maps that show exact wetland boundaries comparable to boundaries derived from ground surveys. Boundaries are therefore generalized in most cases. Consequently, the quality of the wetland data is variable mainly due to source photography, ease or difficulty of interpreting specific wetland types, and survey methods (e.g., level of field effort and state-of-the-art of wetland delineation). See section on "Completeness_Report" for more information.
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| Supplemental Information
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The wetland maps were produced as topical overlays using U.S. Geological Survey topographic maps as the base. The hard copy product is a composite map showing topographic and planimetric features from the USGS map base and wetlands and deepwater habitats from the Service's topical overlay. Thus, the data are intended for use in publications, at a scale of 1:24,000 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 or intended to represent legal or regulatory products.
Comments regarding the interpretation or classification of wetlands or deepwater habitats can be directed to the U.S. Fish and Wildlife Service, Division of Federal Program Activities, Branch of Habitat Assessment http://www.fws.gov/duspit/contactus.htm
These data were developed in conjunction with the publication Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Department of the Interior, Fish and Wildlife Service, Washington, DC. FWS/OBS-79/31. Alpha-numeric map codes have been developed to correspond to the wetland and deepwater classifications described.
These spatial data are not designed to stand alone. They form topical overlays to the U.S. Geological Survey 1:24,000 or 1:25,000 scale topographic quadrangles. Note that coastline delineations were drawn to follow the extent of wetland or deepwater features as described by this project and may not match the coastline shown in other base maps.
Additional information about the creation of various National Wetlands Inventory maps is available in the following documents on the U.S. Fish and Wildlife Service web site:
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/E_Central_Montana.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/Eastern_Montana.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/W_Central_Montana.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/Western_Montana.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/ashton-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/ashton_ne_ashton_se.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/cut bank-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/cut_bank_se.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/dubois-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/ekalaka-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/flathead_valley_montana.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/glasgow-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/glasgow-b.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/hardin-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/havre-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/williston_nw.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/wolf point-a.pdf
http://wetlandsfws.er.usgs.gov/wtlnds/MapReports/wolf point-b.pdf
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