This data set maps impervious surfaces as of 2021 within the 52 towns of the Piscataqua Region
Estuaries Partnership (PREP). It also includes impervious features as of 2015, thereby facilitating
change analysis. The data set identifies human-made surfaces that do not allow water to permeate through
them. Naturally occurring impervious cover, such as exposed bedrock, is not included in the
impervious class.
The data set was derived by updating previously delineated impervious features (developed using 2015 orthophotography)
using 60-cm resolution, leaf-on, 4-band National Agriculture Imagery Program (NAIP) orthophotography acquired in 2021
as the basis for the update. Additional reference data sets, including older orthophoto imagery from 2015, were also
used in the delineation of features.
Funding for this project was provided by a grant from the Piscataqua Regional Estuaries Partnership
as authorized by the U.S. Environmental Protection Agency's National Estuary Program.
This data set is intended to map the location and distribution of human-made impervious cover
in the 52 towns of the Piscataqua Region Estuaries Partnership (PREP). It can be used for water quality
and management applications at large scales.