|Originator||U.S. Fish & Wildlife Service|
|Title||National Wetlands Inventory (NWI), Minnesota|
|Abstract||NWI digital data files are records of wetlands location and classification as defined by the U.S. Fish & Wildlife Service (USFWS). This data set is available in 7.5 minute by 7.5 minute blocks containing ground planimetric coordinates of wetlands point, line, and area features and wetlands attributes. The original digital data as well as the hardcopy maps that were used as the source for the digital data are produced and distributed by the USFWS's National Wetlands Inventory project.
The Minnesota Land Management Information Center (LMIC), now the Minnesota Geospatial Information Office (MnGeo), converted the Minnesota NWI files to ARC/INFO coverage format and edge-matched the files. In cooperation with the Minnesota Department of Natural Resources (DNR) and USFWS, LMIC revised the legends to correct errors, to add items for individual portions of the NWI code, and to add translations to the Circular 39 wetland classification system.
|Purpose||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 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 Completeness element for more information).
|Time Period of Content Date|
|Currentness Reference||Source photography dates ranging from 10/1974 - 5/1988. A list of NWI source photography type, scale, and dates for all quads completed in Minnesota is at: ftp.lmic.state.mn.us/pub/data/phys_biol/water/nwi/nwiphoto.txt|
|Maintenance and Update Frequency||Irregular|
|Spatial Extent of Data||Minnesota|
|Place Keywords||Minnesota, MN|
|Theme Keywords||inlandWaters, wetlands, hydrography, NWI, National Wetlands Inventory|
|Theme Keyword Thesaurus||ISO 19115 Topic Category|
|Use Constraints||Federal, state, and local regulatory agencies with jurisdiction over wetlands may define and describe wetlands in a different manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to define the limits of proprietary jurisdiction of any federal, state, or local government or to establish the geographical scope of the regulatory programs of government agencies. Persons intending to engage in activities involving modifications within or adjacent to wetland areas should seek the advice of appropriate federal, state, or local agencies concerning specified agency regulatory programs and proprietary jurisdictions that may affect such activities. NWI information is not intended to be used as a precise locator of wetland boundaries, for site specific planning or management, or for regulatory purposes.
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. 7-12) entitled NWI Maps: What They Tell Us: www.fws.gov/wetlands/Documents/NWI-Maps-What-They-Tell-Us.pdf
|Contact Person Information||,
U.S. Fish & Wildlife Service
9720 Executive Center Drive
St. Petersburg, FL 33702
Phone: (813) 570-5411
|Browse Graphic||None available|
|Associated Data Sets||1. NWI Update for the East-Central region of Minnesota - deli.dnr.state.mn.us/metadata.html?id=L390008320201
More information about this dataset and the Minnesota NWI Update project can be found here - www.dnr.state.mn.us/eco/wetlands/nwi_proj.html
2. Online Mapping - The USFWS has developed an online application, 'Wetlands Mapper', that allows the general public to view NWI data, to download seamless files and to find web map services. Users can zoom to their area of interest, choose to add several reference layers and print a map. They can also query the map and view an aerial photo or topographic map of the same area. Go to: www.fws.gov/wetlands/Data/Mapper.html
|Section 2||Data Quality|
|Attribute Accuracy||Attribute accuracy is tested by manual comparison of the source with hard copy printouts and/or symbolized display of the digital wetlands data on an interactive computer graphic system. In addition, WAMS software (USFWS-NWI) tests the attributes against a master set of valid wetland attributes.
Note: DNR Waters Water Regime attribute advisory: DNR Waters staff have found a disproportionate number of PEM and PSS wetlands coded with a 'B' water regime in portions of four USGS 100K sheets - the Mora (Q3134), Grantsburg (Q3142), Anoka (Q3534) and Stillwater (Q3542) sheets. The apparent problem resulted from a change in photo interpretive conditions. DNR Waters staff recommend caution in using these combinations of wetland descriptions with these water regimes.
|Logical Consistency||Polygons intersecting the neatline are closed along the border. Segments making up the outer and inner boundaries of a polygon tie end-to-end to completely enclose the area. Line segments are a set of sequentially numbered coordinate pairs. No duplicate features exist nor duplicate points in a data string. Intersecting lines are separated into individual line segments at the point of intersection. Point data are represented by two sets of coordinate pairs, each with the same coordinate values. All nodes are represented by a single coordinate pair which indicates the beginning or end of a line segment. The neatline is generated by connecting the four corners of the digital file, as established during initialization of the digital file. All data crossing the neatline are clipped to the neatline and data within a specified tolerance of the neatline are snapped to the neatline. Tests for logical consistency are performed by WAMS verification software (USFWS-NWI).|
|Completeness||All photo-interpretable wetlands are mapped given considerations of map and photo scale and state-of-the-art wetland delineation techniques. The target mapping unit is an estimate of the minimum-sized wetland that should be consistently mapped. It is not the smallest wetland that appears on the map, but instead it is the size class of the smallest group of wetlands that NWI attempts to map consistently. Users must realize however that some wetland types are conspicuous and readily identified (e.g., ponds) and smaller wetlands of these types may be mapped. Other types (drier-end wetlands and forested wetlands, especially evergreen types) are more difficult to photointerpret and larger ones may be missed.
In general, the minimum mapping unit is from 1 to 3 acres depending on the wetland type and the scale and emulsion of the source aerial photography. In the treeless prairies, 1/4 acre wetlands are mapped. In forested areas, small open water and emergent wetlands are mapped. In regions of the country where evergreen forested wetlands predominate, wetlands smaller than 3 acres may not be mapped. In addition, some small wetlands and those obscured by dense forest cover may not be included in this dataset. In most areas, farmed wetlands are not mapped, with exceptions including prairie pothole-type wetlands and cranberry bogs. Mucklands and other farmed wetlands are usually not shown on the maps. Thus, a detailed on the ground and historical analysis of a single site may result in a revision of the wetland boundaries established through photographic interpretation.
Eight 7.5 minute quadrangles in Minnesota have missing data (some maps state that photography is unavailable): Hancock NW (3211), Hancock (3212), Clontarf North (3213) & Lake Hassel (3214) in Willmar 100K block; Artichoke Lake NW (3209) & Dry Wood Lake (3210) in Milbank 100K block; Blue Grass (2318) in Detroit Lakes 100K block; and Mineral Center OE S (1360) in Grand Portage 100K block. Stevens, Pope, and Swift are the counties primarily affected. 7.5 minute quadrangles along the Minnesota border, with the exception of Wisconsin, contain data from adjacent states.
|Horizontal Positional Accuracy||Horizontal positional accuracy for the digital data is tested by visual comparison of the source with hard copy plots. Enhanced digital data is also snapped to existing quadrangle boundaries and is compared to adjacent files.|
|Vertical Positional Accuracy||Not applicable|
1. National High Altitude Program (NHAP) color infrared and black and white aerial photography, 6/1979 - 5/1988, 1: 58000 and 1:80000.
2. National Aerial Photography Program (NAPP) black and white aerial photography, 1990-1996, 1:40000.
3. Topographic maps, U.S. Geological Survey, 1955-1996, 1:24,000, stable-base material.
4. National Wetlands Inventory maps, U.S. Fish & Wildlife Service, 1988-1992, 1:24,000, stable-base material.
U.S. Fish & Wildlife Service Processing Steps:
NWI maps are compiled through manual photointerpretation of NHAP aerial photography supplemented by Soil Surveys and field checking of wetland photo signatures. Delineated wetland boundaries are manually transferred from interpreted photos to USGS 7.5 minute topographic quadrangle maps and then manually labelled. Quality control steps occur throughout the photointerpretation, map compilation, and map reproduction processes.
Digital wetlands data are either manually digitized or scanned from stable-base copies of the 1:24,000 scale wetlands overlays registered to the standard U.S. Geological Survey (USGS) 7.5 minute quadrangles into topologically correct data files using Wetlands Analytical Mapping System (WAMS) software. Files contain ground planimetric coordinates and wetland attributes. The quadrangles were referenced to the North American Datum of 1927 (NAD27) horizontal datum. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. Manual digitizing used a digitizing table to capture the digital data at a resolution of at least 0.005 inches; attribution was performed as the data were digitized. The determination of scanning versus manual digitizing production method was based on feature density, source map quality, feature symbology, and availability of production systems. The data were checked for position by comparing plots of the digital data to the source material.
LMIC (now MnGeo) Processing Steps:
DLG data for all of Minnesota was downloaded from the NWI ftp server. Wetland codes for each 7.5 minute quadrangle were loaded into a statewide NWI code list from which a unique code number was assigned for each wetland type. Wetland code data from FWS were incorrectly coded into all capital letters on the following 100K sheets: Bigfork, Duluth, Ely, Milbank, Pokegama Lake, Vermilion Lake and Willmar. These data were changed into the correct upper and lower case codes. The DLG files were translated into ARC/INFO double precision net (polygon/line) and point coverages and the Minnesota unique wetland code number was moved into the data set. (nwi2arc.aml). Labelerrors in the net covers were cleaned up if any existed.
The coverages were then snapped to an existing 7.5 minute quadrangle coverage and corner tics were added to create a seamless data base. Additional locational attributes were added and projection information copied into each coverage (nwiproc.aml). Coding and positional discrepancies between 7.5 minute quadrangles were identified and fixed (nwiatt.aml).
7.5 minute quadrangles in Iowa and Canada that contain small areas of Minnesota NWI data were merged into adjacent 7.5 minute quadrangles. The following 100K sheets have such data: Austin, Albert Lea, Hallock and Cavalier. The quads from Charles City and Mason City that were merged into Albert Lea and Austin quads are 4827-4836.
Final NWI data was summarized by type (point, line and polygon), projection information added and the files were exported for archive purposes (nwiexp.aml). The data was transformed into single precision shifted NAD27 coverages for use in PC ARC/INFO. The data was also projected into double precision NAD83 coordinates, but the 7.5 minute quadrangle frame still has the NAD27 boundary.
Staff either at LMIC or DNR converted the data to shapefile format for posting on the DNR Data Deli.
|Section 3||Spatial Data Organization (not used in this metadata)|
|Section 4||Coordinate System|
|Horizontal Coordinate Scheme||Universal Transverse Mercator|
|UTM Zone Number||15E|
|Overview||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.
The wetland classification system is hierarchical, with wetlands and deepwater habitats divided among five major systems at the broadest level. The five systems include Marine (open ocean and associated coastline), Estuarine (salt marshes and brackish tidal water), Riverine (rivers, creeks, and streams), Lacustrine (lakes and deep ponds), and Palustrine (shallow ponds, marshes, swamps, sloughs). Systems are further subdivided into subsystems which reflect hydrologic conditions. Below the subsystem is the class which describes the appearance of the wetland in terms of vegetation or substrate. Each class is further subdivided into subclasses; vegetated subclasses are described in terms of life form and substrate subclasses in terms of composition. The classification system also includes modifiers to describe hydrology (water regime), soils, water chemistry (pH, salinity), and special modifiers relating to man's activities (e.g., impounded, partly drained).
Arc Coverage Version: The wetlands arc coverage is a network coverage containing both polygon and linear features. The naming convention for arc network coverages is NWDPxxxx, where NWDP is the net (polygon/line) coverage prefix and xxxx is the four-digit 7.5-minute quandrangle identifier (see MINN_Q024_CODE). There may also be a wetlands point coverages, NWDXxxxx, where NWDX is the point coverage prefix and xxxx is the four-digit 7.5-minute quadrangle identifier. Note that not every quadrangle has a point file.
In addition to the data fields standard to arc/info coverages, the arc/info attribute tables contain the following information:
NWDPxxxx.PAT (the Polygon Attribute Table):
MINN_Q024_CODE: Unique number for each 7.5 minute quadrangle in Minnesota based on a two digit row and two digit column format. Codes are translated in LEG_Q024 INFO table.
NWI_POLY_CODE: Unique numbering sequence for polygons. Together with the MINN_Q024_CODE each NWI polygon in Minnesota is uniquely identified.
NWI_CODE: Unique code for each occurrence of a wetland type within Minnesota based on the original wetland types from USFWS. See INFO table LEG_NWI.
ACRES: Acres of each individual polygon as computed from the standard arc/info AREA field. Equation is ACRES=AREA/4046.8717
NWDPxxxx.AAT: (he Arc Attribute Table (AAT):
MINN_Q024_CODE: Unique number for each 7.5 minute quadrangle in Minnesota based on a two digit row and two digit column format. See LEG_Q024.
NWI_LINE_CODE: Unique numbering sequence for arcs. Together with the MINN_Q024_CODE each NWI arc in Minnesota is uniquely identified.
NWI_CODE: Unique code for each occurrence of a wetland type within Minnesota based on the original wetland types from USFWS. See LEG_NWI.
MILES: Miles of each individual arc as computed from the standard arc/info LENGTH field. Equation is MILES=LENGTH/1609.344
NWDXxxxx.PAT: (the Point Attribute Table (PAT):
(Note: not every quadrangle has a point file.)
MINN_Q024_CODE: Unique number for each 7.5 minute quadrangle in Minnesota based on a two digit row and two digit column format. See LEG_Q024 INFO table.
NWI_PNT_CODE: Unique numbering sequence for points. Together with the MINN_Q024_CODE each NWI point in Minnesota is uniquely identified.
NWI_CODE: Unique code for each occurrence of a wetland type within Minnesota based on the original wetland types from USFWS. See LEG_NWI INFO table.
LEG_NWI (INFO table)
LEG_NWI is the master legend file for NWI codes, containing all valid wetlands classification codes found in Minnesota. LEG_NWI contains the following data fields:
NWI_CODE: Unique code for each occurrence of a wetland type within Minnesota, based on the original wetland types from USFWS. There are 1,856 unique codes.
FREQ_Q024: The total number of 7.5 minute quadrangles that contain the given MAP_WET_C code. Note that some quadrangles have been merged in the final version to keep the total number of files low. (The frequency can range from 1 to 1742).
MAP_WET_C: The mapped wetland code as it appears on the NWI published maps. The wetland classification system is hierarchical, with wetlands and deepwater habitats divided among five major systems at the broadest level. The five systems include Marine (open ocean and associated coastline), Estuarine (salt marshes and brackish tidal water), Riverine (rivers, creeks, and streams), Lacustrine (lakes and deep ponds), and Palustrine (shallow ponds, marshes, swamps, sloughs). Systems are further subdivided into subsystems which reflect hydrologic conditions. Below the subsystem is the class which describes the appearance of the wetland in terms of vegetation or substrate. Each class is further subdivided into subclasses; vegetated subclasses are described in terms of life form and substrate subclasses in terms of composition. The classification system also includes modifiers to describe hydrology (water regime), soils, water chemistry (pH, salinity), and special modifiers relating to man's activities (e.g., impounded, partly drained).
FIN_WET_C: Same as attribute label MAP_WET_C only does not represent the final NWI map. It is essentially a cleaned up version based on discussion between Minnesota Department of Natural Resources (MnDNR) staff and local USFWS staff. Some codes were not used uniformly throughout Minnesota and other codes changed over time. Based on correspondence with Erv Berglund (MnDNR) and Nicholas Rowse (USFWS) 1995 and 1996.
MINN_Q024_CODE: The unique 7.5 minute quadrangle number where the given MAP_WET_C code can be found as an example. See LEG_Q024 INFO table.
Definitions of the individual portions of the code appear below:
System Attributes: SYS_C: The wetland System code portion of FIN_WET_C. See LEG_SYSTEM INFO table. Marine and Estuarine systems are not found in Minnesota.
Value=L: Lacustrine (lakes and deep ponds) - Lacustrine System include wetlands and deepwater habitats with all of the following three characteristics: 1) Situated in a topographic depression or a dammed river channel; 2)Lacking trees, shrubs, persistent emergents, emergent mosses or lichens with greater than 30 percent areal coverage; 3)Total area exceeds 8 hectares (20 acres). Basins or catchments less than 8 hectares in size are included if they have at least one of the following characteristics: A wave-formed or bedrock feature forms all or part of the shoreline boundary; or the catchment has at low water a depth greater than 2 meters (6 feet) in the deepest part of the basin.
Value = P: Palustrine (shallow ponds, marshes, swamps and sloughs) - Palustrine Systems include all nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses or lichens, and all such wetlands that occur in tidal areas where salinity due to ocean-derived salts is below 0.5 ppt. Wetlands lacking such vegetation are also included if they exhibit all of the following four characteristics: 1) Are less than 8 hectares (20 acres); 2) Do not have an active wave-formed or bedrock shoreline feature; 3 Have at low water a depth less than 2 meters (6 feet) in the deepest part of the basin; 4) Have a salinity due to ocean-derived salts of less than 0.5 ppt. All water bodies that are less than 8 hectares (20 acres) in size are considered to be in the Palustrine System unless depth information is available, or unless an active wave-formed or bedrock shoreline is visible.
Value = R: Riverine (rivers, creeks and streams) - Riverine Systems are contained in natural or artificial channels periodically or continuously containing flowing water. Upland islands or Palustrine wetlands may occur in the channel, but they are not part of the Riverine System.
Value = U: Upland - Primarily represents upland areas, but may include unclassified wetlands such as non photo-identifiable area and/or unintentional omissions.
Subsystem Attributes: SUBSYS_C: The wetland Subsystem code portion of FIN_WET_C. See LEG_SUBSYS INFO table.
Value = L1: Limnetic - Extends outward from Littoral boundary and includes deepwater habitats within the Lacustrine System.
Value = L2: Littoral - Extends from shoreward boundary to 2 meters (6 feet) below annual low water or to the maximum extent of non-persistent emergents, if these grow at greater than 2 meters.
Value = R1: Lower Perennial - This Subsystem is characterized by a low gradient and slow water velocity. There is no tidal influence, and some water flows throughout the year. The substrate consists mainly of sand and mud. The floodplain is well developed. Oxygen deficits may sometimes occur.
Value = R2: Upper Perennial - This Subsystem is characterized by a high gradient and fast water velocity. There is no tidal influence, and some water flows throughout the year. The substrate consists of rock, cobbles, or gravel with occasional patches of sand. There is very little floodplain development.
Value = R3: Intermittent - This Subsystem includes channels that contain water only part of the year, but may contain isolated permanent pools when the flow stops.
Value = R4: Unknown Perennial - This Subsystem designation was created specifically for use when the distinction between lower perennial, upper perennial and tidal cannot be made from aerial photography and no collateral data is available.
CLASS and SUBCLASS attributes:
CLASS1_C, CLASS2_C, SCLASS1_C and SCLASS2_C: The wetland Class and Subclass code portion of FIN_WET_C. The Class code describes the general appearance of the habitat in terms of either the dominant life form of the vegetation or the physiography and composition of the substrate. Life forms (e.g. trees, shrubs, emergents) are used to define classes because they are easily recognizable, do not change distribution rapidly, and have traditionally been used to classify wetlands. Mixed classes (CLASS2_C) are used as sparingly as possible, under two main conditions: (1) The wetland contains two or more distinct cover types each encompassing at least 30 percent areal coverage of the highest life form, but is too small in size to allow separate delineation of each cover type; and (2) The wetland contains 2 or more classes or subclasses each comprising at least 30 percent areal coverage so evenly interspersed that separate delineation is not possible at the scale of photography used for NWI classification. Mixed subclasses are also allowed and follow the same rules for mixed classes.
LEG_CLASS, LEG_CLASS1 & LEG_CLASS2 (identical legends) and LEG_SCLASS, LEG_SCLASS1 & LEG_SCLASS2 (identical legends)
Value = AB: Aquatic Bed - Includes wetlands and deepwater habitats dominated by plants that grow principally on or below the surface of the water for most of the growing season in most years. Subclasses include: AB1 = Algal, AB2 = Aquatic Moss, AB3 = Rooted Vascular, AB4 = Floating Vascular, AB5 = Unknown Submergent & AB6 = Unknown Surface.
Value = EM: Emergent - Characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens. This vegetation is present for most of the growing season in most years. Subclasses include: EM1 = Persistent (plants that normally remain standing at least until the beginning of the next growing season) & EM2 = Nonpersistent (plants which fall to the surface of the substrate or below the surface of the water at the end of the growing season). Earlier maps may also contain the following subclasses: EM3 = Narrow-leaved Nonpersistent, EM4 = Broad-leaved Nonpersistent, EM5 = Narrow-leaved Persistent & EM6 = Broad-leaved Persistent.
Value = FO: Forested - Woody vegetation less than 6 meters (20 feet) tall. The species include true shrubs, young trees (saplings) or trees that are small or stunted because of environmental conditions. Subclass determination is based on which type represents more than 50 percent of the areal canopy coverage during the leaf-on period and include: FO1 = Broad-leaved Deciduous, FO2 = Needle-leaved Deciduous, FO3 = Broad-leaved Evergreen, FO4 = Needle-leaved Evergreen, FO5 = Dead, FO6 = Deciduous & FO7 = Evergreen.
Value = ML: Moss/Lichen - Areas where mosses or lichens cover substrates other than rock and where emergents, shrubs, or trees make up less than 30 percent of the areal cover. Subclasses include: ML1 = Moss & ML2 = Lichen.
Value = OW: Open Water - Open water, no visible vegetation. Earlier maps used the OW class, while present mapping conventions use the UB class.
Value = RB: Rock Bottom - Includes all wetlands and deepwater habitats with substrates having areal cover of stones, boulders or bedrock 75 percent or greater and vegetative cover of less than 30 percent. Subclasses include: RB1 = Bedrock & RB2 = Rubble.
Value = RS: Rocky Shore - High energy shoreline characterized by bedrock, stones or boulders which singly or in combination have an areal cover of 75 percent or more and an areal coverage by vegetation of less than 30 percent. Subclasses include: RS1 = Bedrock & RS2 = Rubble.
Value = SB: Streambed - Includes all wetland contained within the Intermittent Subsystem of the Riverine System and all channels of the Estuarine System or of the Tidal Subsystem of the Riverine System that are completely dewatered at low tide. Subclasses include: SB1 = Bedrock, SB2 = Rubble, SB3 = Cobble-Gravel, SB4 = Sand, SB5 = Mud, SB6 = Organic & SB7 = Vegetated (pioneer plants).
Value = SS: Scrub/Shrub - Woody vegetation less than 6 meters (20 feet) tall. The species include true shrubs, young trees (saplings) or trees that are small or stunted because of environmental conditions. Subclass determination is based on which type represents more than 50 percent of the areal canopy coverage during the leaf-on period and include: SS1 = Broad-leaved Deciduous, SS2 = Needle-leaved Deciduous, SS3 = Broad-leaved Evergreen, SS4 = Needle-leaved Evergreen, SS5 = Dead, SS6 = Deciduous (used if deciduous woody vegetation cannot be identified on aerial photography as either Broad-leaved or Needle-leaved) & SS7 = Evergreen (used if evergreen woody vegetation cannot be identified on aerial photography as either Broad-leaved or Needle-leaved).
Value = UB: Unconsolidated Bottom - Includes all wetlands and deepwater habitats with at least 25 percent cover of particles smaller than stones (less than 6-7 cm.), and a vegetative cover less than 30 percent.
Value = US: Unconsolidated Shore - Includes all wetland habitats having unconsolidated substrates with less than 75 percent areal cover of stones, boulders or bedrock and less than 30 percent areal cover of vegetation other than pioneering plants. Landforms such as beaches, bars, and flats are included in the Unconsolidated Shore Class.
Water Regime Attribute: WREG_C: The wetland Water Regime Modifier code portion of FIN_WET_C. Precise description of hydrologic characteristics requires detailed knowledge of the duration and timing of surface inundation, both yearly and long-term, as well as an understanding of groundwater fluctuations. Because such information is seldom available, the water regimes that, in part, determine characteristic wetland and deepwater plant and animal communities are described here in only general terms. Water regimes are grouped under two major headings, Tidal and Nontidal. The Tidal Water Regime does not occur in Minnesota. See LEG_WREG INFO table.
Value = A: Temporarily Flooded - Surface water present for brief periods during the growing season, but the water table usually lies well below the soil surface. Plants that grow both in uplands and wetlands are characteristic of this water regime.
Value = B: Saturated - The substrate is saturated to the surface for extended periods during the growing season, but surface water is seldom present.
Value = C: Seasonally Flooded - Surface water is present for extended periods especially early in the growing season, but is absent by the end of the growing season in most years. The water table after flooding ceases is very variable, extending from saturated to a water table well below the ground surface.
Value = D: Seasonally Well-drained - Surface water is present for extended periods especially early in the growing season. The water table after flooding ceases falls well below the ground surface. (Not used on all maps.)
Value = E: Seasonally Saturated - Surface water is present for extended periods especially early in the growing season, and remains saturated near the surface for most of the growing season. (Not used on all maps.)
Value = F: Semipermanently Flooded - Surface water persists throughout the growing season in most years. When surface water is absent, the water table is usually at or very near the land surface.
Value = G: Intermittently Exposed - Surface water is present throughout the year except in years of extreme drought.
Value = H: Permanently Flooded - Water covers the land surface throughout the year in all years.
Value = J: Intermittently Flooded - The substrate is usually exposed, but surface water is present for variable periods without detectable seasonal periodicity. Weeks, months or even years may intervene between periods of inundation. The dominant plant communities under this regime may change as soil moisture conditions change.
Value = K: Artificially Flooded - The amount and duration of flooding is controlled by means of pumps or siphons in combination with dikes or dams. Water and waste-water treatment facilities are included in this modifier.
Value = U: Unknown - The water regime is not known.
Value = W: Intermittently Flooded/Temporary - Exhibits features of both Intermittently Flooded (J) and Temporary (A) water regimes. (Not used on all maps.)
Value = Y: Saturated/Semipermanent/Seasonals - Exhibits features of the Saturated (B), Semipermanent (F) and Seasonal (C, D and E) water regimes. (Not used on all maps.
Value = Z: Intermittently Exposed/Permanent - Exhibits features of both Intermittently Exposed (G) and Permanent (H) water regimes. (Not used on all maps.)
Soil Modifier Attribute: SOILM_C: The wetland Soil Modifier code portion of FIN_WET_C. See LEG_SOILM INFO table.
Value = g: Organic soil modifier - Sometimes used to indicate peatlands, fens or bogs.
Value = n: Mineral soils - Sometimes used to indicate the presence of mineral soils as it pertains to soil taxonomy.
Special Modifier Attributes: SMOD1_C & SMOD2_C: The wetland Special Modifier code portion of FIN_WET_C. Many wetlands or deepwater habitats are man-made, and natural ones have been modified to some degree by the activities of man or beavers. Since the nature of these modifications often greatly influences the character of such habitats, special modifying terms have been included here to emphasize their importance. Modifiers are used singly or in combination wherever they apply to wetlands and deepwater habitats. In Minnesota, there are not more than 2 modifiers used for a given wetland. See LEG_SMOD, LEG_SMOD1, & LEG_SMOD2 (identical legends).
Value = b: Beaver - Created or modified by the action of a beaver.
Value = d: Partly Drained - The water level has been artificially lowered, but the area is still classified as wetland because soil moisture is sufficient to produce hydrophytes.
Value = f: Farmed - The soil surface has been mechanically or physically altered for production of crops, but hydrophytes will become reestablished if farming is discontinued.
Value = h: Diked/Impounded - Created or modified by a man-made barrier or dam which obstructs the inflow or outflow of water.
Value = r: Artificial - Substrates classified as Rock Bottom (RB), Unconsolidated Bottom (UB), Rocky Shore (RS) and Unconsolidated Shore (US) that were emplaced by man using natural or synthetic materials. Jetties and breakwaters are examples of Artificial Rocky Shores.
Value = s: Spoil - Wetland or deepwater habitat where the substrate is a result of the deposition of spoil materials.
Value = x: Excavated - Lies within a basin or channel excavated by man. This includes all landcut canals, ditches, dugouts, stockponds, and farm ponds. Some of these categories may also be diked/impounded (h).
Circular 39 Attribute:CIRC39_C: The Circular 39 Classification outlines a means of classifying the wetland basins of the U.S. It is composed of 20 types of which 8 are found in Minnesota. Four additional types have been defined to completely classify the Minnesota NWI wetlands into Circular 39 types. See LEG_CIRC39 INFO table.
Value = 0: No wetland data, usually indicative of line comprising a polygon boundary. NWI_CODE is 9999.
Value = 1: Seasonally flooded basin or flat. Soil is covered with water or is waterlogged during variable seasonal periods but usually is well-drained during much of the growing season. Vegetation varies greatly according to season and duration of flooding: from bottomland hardwoods to herbaceous plants. Note that the term seasonally flooded does not have the same meaning in Circular 39 and NWI.
Value = 2: Wet meadow. Soil is usually without standing water during most of the growing season but is waterlogged within at least a few inches of the surface. Meadows may fill shallow basins, sloughs, or farmland sags, or these meadows may border shallow marshes on the landward side. Vegetation includes grasses, sedges, rushes and various broad-leaved plants. Other wetland plant community types include low prairies, sedge meadows and calcareous fens.
Value = 3: Shallow marsh. Soil is usually waterlogged early during the growing season and may often be covered with as much as 6 inches or more of water. These marshes may nearly fill shallow lake basins or sloughs, or may border deep marshes on the landward side. These are common as seep areas on irrigated lands. Vegetation includes grass, bulrush, spikerush and various other marsh plants such as cattail, arrowhead, pickerelweed and smartweed.
Value = 4: Deep marsh. Soil is usually covered with 6 nches to 3 feet or more of water during the growing season. These deep marshes may completely fill shallow lake basins, potholes, limestone sinks and sloughs, or they may border open water in such depressions. Vegetation includes cattail, reed, bulrush, spikerush and wildrice. In open areas, pondweed, naiad, coontail, water-milfoil, waterweed, duckweed, waterlily or spatterdock may occur.
Value = 5: Shallow open water. Shallow ponds and reservoirs are included in this type. Water is usually less than 10 feet deep and fringed by a border of emergent vegetation similar to open areas of Type 4.
Value = 6: Shrub swamp. Soil is usually waterlogged during the growing season and is often covered with as much as 6 inches of water. These occur mostly along sluggish streams and occasionally on flood plains. Vegetation includes alder, willow, buttonbush, dogwood and swamp-privet.
Value = 7: Wooded swamps. Soil is waterlogged at least to within a few inches of the surface during the growing season and is often covered with as much as 1' of water. These occur mostly along sluggish streams, on old riverine oxbows, on flat uplands and in ancient lake basins. Forest vegetation includes tamarack, arborvitae, black spruce, balsam fir, red maple and black ash. Deciduous swamps frequently support beds of duckweed and smartweed. Other wetland plant community types include lowland hardwood swamps and coniferous swamps.
Value = 8: Bogs. Soil is usually waterlogged. These occur mostly in ancient lake basins, on flat uplands and along sluggish streams. Vegetation is woody or herbaceous or both, usually on a spongy covering of mosses. Typical plants are heath shrub, sphagnum moss and sedge. In the North, leatherleaf, Labrador tea, cranberry and cottongrass are often present. Scattered, often stunted, black spruce and tamarack may occur.
Value = 80: Municipal and industrial activities, water regime (WREG_C) is K.
Value = 90: Riverine systems, system (SYS_C) is R.
Value = 98: Uplands, system (SYS_C) is U.
Value = 99: Area outside Minnesota, system (SYS_C) is O.
|Detailed Citation||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 pages:
and related Wetland Code Interpreter tool:
Santos, Kim M. and Joan E. Gauster. 1993. Users Guide to National Wetlands Inventory Maps (Region 3) and to Classification of Wetlands and Deepwater Habitats of the United States.
Shaw, Samuel P. and C. Gordon Fredine. 1956. Wetlands of the United States, their extent and their value to waterfowl and other wildlife. Circular 39. Fish & Wildlife Service, United States Department of the Interior.
|Publisher||U.S. Fish & Wildlife Service|
|Contact Person Information||Nancy Rader,
GIS Data Coordinator|
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street, Room 300
St. Paul, MN 55155
|Distributor's Data Set Identifier||NWI Minnesota|
|Distribution Liability||1. The Minnesota Department of Natural Resources General Geographic Data License Agreement is online: www.dnr.state.mn.us/sitetools/data_software_license.html
2. MnGeo's data disclaimer is online: www.mngeo.state.mn.us/chouse/disclaimer.html
|Ordering Instructions||1. Shapefile: Download files from the Minnesota Department of Natural Resources through their Data Deli: deli.dnr.state.mn.us (choose National Wetlands Inventory Polygons, Lines and/or Points)
2. For other formats and options, see the U.S. Fish & Wildlife website: www.fws.gov/wetlands/
Note, however, that the files are the original data and will not contain the modifications made at MnGeo and DNR (e.g., edgematching, splitting codes into component parts, and addition of Circular 39 codes).
|Online Linkage||I AGREE to the notice in "Distribution Liability" above. Clicking to agree will either begin the download process or link to download information. See "Ordering Instructions" above for details.|
|Section 7||Metadata Reference|
|Contact Person Information||Nancy Rader,
GIS Data Coordinator|
Minnesota Geospatial Information Office (MnGeo)
658 Cedar Street, Room 300
St. Paul, MN 55155
|Metadata Standard Name||Minnesota Geographic Metadata Guidelines|
|Metadata Standard Version||1.2|
|Metadata Standard Online Linkage||http://www.mngeo.state.mn.us/committee/standards/mgmg/metadata.htm|