Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Imperviousness
This data set represents the mean percent impervious surface from the Imperviousness Layer of the 
National Land Cover Dataset 2001 (LaMotte and Wieczorek, 2010), compiled for every catchment of 
NHDPlus for the conterminous United States. The source data set represents imperviousness for the 
conterminous United …