In order to accomplish its mission of management and protection of valuable natural resources, the North Carolina Division of Coastal Management (DCM) has developed wetland inventory and assessment tools that should greatly improve wetland resource management and planning in the coastal area. Specifically, DCM has developed a wetland Geographic Information System (GIS) that effectively inventories the type, amount, location and the functional significance of wetlands located in the 20 counties defined by the Coastal Area Management Act and an additional 17 counties within the NC Inner Coastal Plain. DCM's wetland type maps combine the US Fish and Wildlife Service's National Wetland Inventory (NWI) maps, the Natural Resources Conservation Service's soils surveys, and 1989 and 1994 Landsat TM satellite imagery as well as field reconnaissance data. By using multiple data sources, DCM has attempted to maximize the strengths of each source, while minimizing its weaknesses. The resulting wetland type maps show the location, size and type of wetlands more accurately, clearly and comprehensively than ever before. In addition to identifying the location and extent of wetlands, DCM's challenge has been to develop a wetland functional assessment procedure which would provide a meaningful evaluation of wetland functional significance. Consequently, DCM developed a GIS functional assessment model commonly known as The North Carolina Coastal Region Evaluation of Wetland Significance or NC-CREWS. NC-CREWS functions in a hierarchical manner, analyzing three primary wetland functions (Hydrology, Water Quality and Wildlife Habitat), seven wetland subfunctions and 39 landscape and wetland parameters. Wetlands are assigned ratings of Beneficial Significance, Substantial Significance or Exceptional Significance, depending on how well they perform the various wetland functions. The relative risk to watershed integrity posed by the loss of specific wetlands is also measured and labeled "Potential Risk". Although the NCCREWS model was developed for the NC Coastal area, it has the potential of being adapted to other areas. A number of states are already exploring how it could be used to improve their wetland conservation efforts.
These data were created to assist local, state, and federal government agencies and others in making resource management decisions and in land use planning.
Because of overall data filesize, the statewide dataset was clipped by riverbasin. coverage filesizes: (by riverbasin, in megabytes): Cape Fear (/cpf_crews) - 97.8 Chowan (/cho_crews) - 17.2 Lumber (/lbr_crews) - 40.3 Neuse (/neu_crews) - 64.9 Pasquotank (/pas_crews) - 26.7 Roanoke (/roa_crews) - 18.3 Tar-Pamlico (/tar_crews) - 40.8 White Oak (/wok_crews) - 23.6
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These data are advisory in nature. They are not a substitute for an on-site determination of jurisdictional wetlands. Although every effort was taken to ensure the accuracy and validity of wetland location and extent, these data contain inherent errors and limits. Surfaces mapped from remotely sensed data have certain degrees of error and accuracy limits. The actual boundaries may differ from those shown in these data. Wetlands smaller than one acre often are overlooked at this scale and may not be included in these data. There also may be cases in which regulatory agencies' determinations of the existence or lack of wetlands differ from these data. While every effort has been made to ensure that these data are accurate and reliable within limits of the current state of the art, DCM cannot assume liability for any damages caused by inaccuracies in the map of supporting data. DCM makes no warranty, express or implied, nor does the fact of distribution constitute such a warranty.
A comprehensive accuracy assessment of these data was performed by DCM using funds provided by the Environmental Protection Agency. For more information contact DCM.
These data were originally processed by 14-digit hydrologic units (HU). Upon completion, all hydrologic units were joined together using the Arc/Info "mapjoin" command and then clipped by county. Digital data and hard copy maps were checked extensively for consistency and completeness by GIS analysts and wetland specialists on DCM's staff. There may be inconsistencies in these data along county boundaries. This is due mainly to the fact that the soils data used for development of this data set were mapped by county and was not edge-matched or otherwise made consistent at county boundaries.
These wetland functional significance data represent watersheds completely within the 20 coastal counties under the jurisdiction of the Division of Coastal Management and an additional 17 counties within the NC Inner Coastal Plain. The data is not a substitute for an on-site determination of jurisdictional wetlands. Wetlands smaller than one acre are often overlooked at this scale and may not be included in these data. Linear wetlands less than 40 feet wide are also often overlooked at this scale and may not be included in these data.
Accuracy varies depending on source scale and/or resolution of the data layer from which each wetland polygon is derived.
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Wetland data that are stored quad by quad are joined and clipped by watershed boundary. The watershed's wetland information is analyzed using the NC-CREWS procedure, a wetland significance assessment model consisting of a series of Arc Macro Language (AML) programs. NC-CREWS analyzes how well each individual wetland polygon performs water quality, hydrology, and habitat functions. Water quality functions include a non-point source function and a flood water cleansing function. Hydrology functions such as surface runoff storage, flood water storage and shoreline stabilization are analyzed. The Habitat function considers terrestrial and aquatic wildlife. The GIS data layers considered in the NC-CREWS model include: (1) Wetland boundaries and types (DCM wetland type data) (2) Soils data (3) Land Use/Land Cover (4) Hydrography (5) Watershed Boundaries (6) Endangered species occurrences (7) Estuarine Primary nursery areas (8) Water quality classifications (9) NC Unique natural ecosystem and special wildlife habitat areas (10) Anadromous fish spawning areas For more information on NC-CREWS, please see DCM report "NC-CREWS: North Carolina Coastal Region Evaluation of Wetland Significance".
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Dataset moved.
Internal feature number.
ESRI
Feature geometry.
ESRI
Area of Polygon
Software Computed
Perimeter of Polygon
Software computed
Internal Feature Number
Software Computed
Feature Identification Number
User Defined
Wetland Type
NC Division of Coastal Management
Overall Wetland Rating
NC Division of Coastal Management
Beneficial Functional Significance
NC Division of Coastal Management
Substantial Functional Significance
NC Division of Coastal Management
Exceptional Functional Significance
NC Division of Coastal Management
NC Division of Coastal Management
Water Quality Function
NC Division of Coastal Management
Non-Point Source Sub-Function
NC Division of Coastal Management
Flood Water Cleansing Sub-Function
NC Division of Coastal Management
Hydrology Function
NC Division of Coastal Management
Surface Runoff Storage Sub-Function
NC Division of Coastal Management
Flood Water Storage Sub-Function
NC Division of Coastal Management
Shoreline Stabilization Sub-Function
NC Division of Coastal Management
Habitat Function
NC Division of Coastal Management
Terrestrial Wildlife Sub-Function
NC Division of Coastal Management
Aquatic Life Sub-Function
NC Division of Coastal Management
Potential Risk Factor
NC Division of Coastal Management
Landscape Character
NC Division of Coastal Management
Watershed Water Quality
NC Division of Coastal Managment
Replacement Difficulty for Wetland Function
NC Division of Coastal Management
Enhancement Potential of Site
NC Division of Coastal Management
Hydrogeomorphic Class
The overall rating, functions and subfunctions are each coded according to the following scheme: -1 -Unable to rate 0 -Non Wetland 1 -Beneficial Significance 2 -Substantial Significance 3 -Exceptional Significance The exceptions to this rule are those wetlands that are rated as having exceptional significance due to over-riding considerations. These polygons will have a value of 3 for their overall rating and a value of 0 for all functions and sub-functions.
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