Coefficients of Imperviousness

Impervious Surface Analysis Tool (ISAT)

Reference: NOAA Coastal Connections Newsletter Focusing on Impervious Surfaces. 2004.



The Impervious Surface Analysis Tool (ISAT), an ArcView 3.x extension, is used to calculate the percentage of impervious surface area of user-selected geographic areas (e.g. watersheds, municipalities, subdivisions). ISAT was developed as a partnership between NEMO and the National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center, based on a prototype created by NEMO. ISAT can be downloaded free of charge from the Coastal Services Center Digital Coast website.


ISAT was developed using detailed IS data from several states, but the long term goal of NEMO, CSC and the National NEMO Network is to develop a set of state or region-specific coefficients. Shown in the photo are UConn’s Sandy Prisloe and CSC’s Dave Eslinger leading an ISAT workshop during the summer of 2002. Participants were both town officials from CT, and NEMO Network staff from around the country.