College of Agriculture and Natural Resources
Center for Land Use Education and Research
Impervious Surfaces

Long Island Sound Regional Impervious Surface Study


Impervious Surfaces:
Long Island Sound Regional Impervious Surface Study

Long Island Sound Study


The objective of this project was to derive a consistent set of impervious surface estimates for the years 1985, 1990, 1995, and 2002 for the Connecticut and New York portions of the Long Island Sound watershed. The goal was to track historical changes in impervious cover over the study area and to provide a standardized set of information that can be used to compare changes in impervious surfaces over time and to provide a set of data that can be used to study how changes in imperviousness might relate to population growth, water quality and other factors.


Many of the threats posed to Long Island Sound are directly or indirectly the result of the urbanization of the watershed, particularly with the increase of impervious surfaces. Impervious surfaces such as asphalt, concrete and rooftops prevent percolation of water into the soil, creating a negative impact on water quantity and water quality. Impacts related to the increase in impervious surfaces include: deterioration of water quality resulting in polluted surface waters, reduced ground water recharge resulting in a decrease in available sub-surface ground water, and an increase in runoff volume resulting in flood control problems. Over the past 15 years, the amount of impervious surface coverage in a watershed has become widely accepted as a reliable indicator of the potential impact of developed land on water resources. Simply put, as impervious surface increases, water quality decreases.

Funded by the EPA Long Island Sound Office

Understanding the amount of imperviousness in the Long island Sound watershed region is an important part of the effort to monitor and evaluate the health of Long Island Sound. Having impervious surface information is a beneficial component for the implementation of the Long Island Sound Study Comprehensive Conservation and Management Plan (CCMP). As such, the EPA Long Island Sound Office in addition to the states of New York and Connecticut are interested in tracking the growth of impervious surfaces.