Impervious Surfaces and Water Quality

As part of a study funded by NOAA's Coastal Services Center, UConn researchers Mr. James Hurd and Dr. Daniel Civco conducted a preliminary investigation to develop consistent impervious surface estimates for four years (1985, 1990, 1995, 2002) and to relate these historical water quality information. Water quality information from the USGS was obtained for seven regional watersheds located in Connecticut. The goal was to substantiate further the often-assumed adverse influence of impervious surfaces on water quality.

The results indicate that most of the water quality parameters expected to be influenced by impervious surfaces did in fact correlate with the amount of impervious surface in the watershed, and that these changed over time as impervious surface increased. However, while trends were identified, given the limited number of watersheds included in the study (due to available water quality information), it was difficult to make a conclusive statement. The following chart provides the results of impervious surface and chloride for all watersheds and dates. The image shows 2002 impervious surfaces for the Salmon river watershed up-stream from the USGS gauging station. Red identifies the highest level of imperviousness. For more information, please read the report.