Urban development dramatically alters drainage systems through landscaping, changes in surface cover (pavements and buildings), and the addition of new storm sewers and ponds. This produces short-term effects on stream temperatures through intensive rainfall, and long-term effects through changes in infiltration, ground water flow, and base flow in no-rain periods. A significant change in water temperature can also cause the loss of fish habitat in coldwater streams. This research, representing the second phase of a project commissioned by the Minnesota Pollution Control Agency, sought to develop a tool to assess the impacts of urban developments on trout streams. In doing so, researchers assembled and studied the data already collected on stream temperature and a variety of surfaces by state and local agencies, and collected additional data for a thorough analysis of the system.