In the spring of 1993, the New England Interstate Water Pollution Control Commission through a grant from EPA, together with the City of Stamford, Connecticut, and CH2M HILL funded a two-part study of nitrogen reduction techniques in Stamford, Connecticut, as part of the Long Island Sound Action Plan Demonstration Project. The City of Stamford is located in the southwestern corner of Connecticut, on the northern bank of Long Island Sound. The second part of the study involved assessing point-nonpoint source trading potential in the Stamford area by comparing the effectiveness of reducing nonpoint source nitrogen loads with point source nitrogen loads to Long Island Sound. The subject of this paper is the second part of the study, the assessment of point-nonpoint source nitrogen trading. The study area, shown in Figure 1, consists of the urban coastal area of Stamford and two watersheds, the Rippowam River Watershed and the Noroton River Watershed.
All areas drain to Long Island Sound.
The Stamford coastal area encompasses approximately 7 square miles of 100 percent sewered area. The watersheds encompass 35 square miles and cross political boundaries, intersecting the towns of Stamford, Darien, and New Canaan, Connecticut, and Westchester County, New York. Land cover in the watersheds is approximately 50 percent urban and 50 percent wooded and includes a small amount of agricultural terrain. Approximately 20 percent of the watershed area has sewers. The trading concept in the context of the study focused on the cost-effectiveness of reducing nitrogen loads through nonpoint source controls versus point source controls within the study area.