As increasing regulatory pressure on point sources of pollution leads to reduction of effluent, nonpoint sources become a larger percentage of the total pollution load. The effects of nonpoint pollutants on specific waters vary and may not always be fully assessed. However, it is well known that these pollutants have harmful effects on drinking water supplies, recreation, fisheries, and wildlife. Determining contributing sources of water pollution in relation to land use of the Quinnipiac River Basin has been an ongoing study at the Environmental Chemistry Lab at the Yale School of Forestry and Environmental Studies.

The Quinnipiac River drains most of New Haven County, in south-central Connecticut, and empties into Long Island Sound at New Haven Harbor. Many areas of the Quinnipiac Basin Watershed are highly developed with residential communities, industry, and agriculture. Consequently, water quality and pollution sources continue to be issues requiring further analysis to integrate into a sound management plan for the watershed. This study examines the relationship between land uses and nonpoint source pollution on a portion of the Quinnipiac River Basin.