NC-CREWS Wetland Functional Assessment
The North Carolina Coastal Region Evaluation of Wetland Significance, or NC-CREWS, is a watershed-based wetlands functional assessment model that uses geographic information systems (GIS) software and data to assess the level of water quality, wildlife habitat, and hydrologic functions of individual wetlands. The primary objective of the NC-CREWS wetland functional assessment is to provide users with information about the relative ecological importance of wetlands for use in planning and the overall management of wetlands.
It is useful in determining where development should not be planned, or where certain types of development are best suited to and compatible with the habitat. Where wetland impacts are unavoidable, NC-CREWS can significantly improve avoidance and minimization of significant and irreversible adverse impacts to the most valuable wetland ecosystems.
The NC-CREWS Procedure
The structure of NC-CREWS is hierarchical. The model consists of four levels: (1) overall functional significance of the wetland; (2) specific functions and potential risk of wetland loss; (3) subfunctions; and (4) parameters and subparameters evaluated to determine the level and extent of functions. The model evaluates 39 separate characteristics of the wetland and its watershed (14-digit hydrologic units). Using GIS analysis, a High, Medium, or Low rating is assigned to each of the subparameters that describe the landscape and internal wetland characteristics. The subparameter ratings are successively combined to produce ratings for parameters; parameter ratings are combined to produce ratings for subfunctions; subfunction ratings are combined to produce ratings for primary functions. The primary functions are combined to form an overall wetland rating of the wetland’s ecological significance. NC-CREWS produces 3 possible overall wetland rating scores: Exceptional Significance, Substantial Significance, or Beneficial Significance.
More details about the NC-CREWS procedure can be found in DCM’s publication NC-CREWS: North Carolina Coastal Region Evaluation of Wetland Significance (1999). This document describes the data inputs, the procedure, and results in detail. For other wetland-related documents, click here.