Klemow, K.M., M. Mohseni, D. Clancy, D. Grassi, T. Massenheimer, H. Quick, S. Schoenwolf, and M. Wassel. 1997. FURTHER EVALUATION OF NATIONAL WETLAND INVENTORY MAPS FOR NORTHEASTERN PENNSYLVANIA. Contributed paper: Pennsylvania Academy of Science meeting. Abstract: Journal of the Pennsylvania Academy of Science 70:179.
A previous analysis of a 78 sq. km. area in Luzerne County revealed that the National Wetland Inventory (NWI) maps produced by the US Fish & Wildlife Service apparently understated the amount of actual wetland acreage. The purpose of this paper is twofold: (1) to determine whether the same trend holds when a larger area is examined, and (2) to evaluate the accuracy of NWI maps using in-field delineations. When the analysis was extended to 260 sq. km., we noted that NWI maps excluded 26% of all areas mapped as open water, 66% mapped as having hydric soil, and 97% mapped as having sub-hydric soil. Thus, the trend observed in the analysis of the smaller area continued when the sample size was enlarged. The in-field delineations confirmed that areas mapped as having hydric and sub-hydric soils tended to contain wetland. This analysis confirmed our earlier conclusion that interested parties seeking to know whether a particular piece of property contains wetlands should not rely on NWI maps to provide that information.