Rapid urbanization and urban sustainability have become increasing concerns, from local to global scales. As cities grow, they are increasingly reliant on the importation of natural resources to support processes within the urban center. In return for these inputs, cities export products, services, capital, and wastes, as well as unused natural resources. This project was begun in November of 2002 by three FES professors - Shimon Anisfeld, Sheila Olmstead, and Xuemei Bai. With student research assistants Hahn-Ning Chou and Ying Qiu, they are studying the flow of water and nitrogen through the urban ecosystem of New Haven. Often water and nitrogen budgets are studied at the watershed level, however, this project is unique in that the city limits are used as the boundary. This allows us to better understand anthropogenic influences on the flow of water and nitrogen in and out of cities. The project was undertaken in two parts. The first part included constructing a model capable of determining the factors that affect different sectors of water use, and analyzing patterns of residential water use in New Haven. The second component of the project was to identify and quantify the inflows, outflows, and unaccounted sources of nitrogen flowing through New Haven's controlled and uncontrolled waters. Water and nitrogen flows were studied for the five-year period between January 1997 and December 2002.