The Toronto and Region Conservation Authority is one of 38 Conservation Authorities in the province of Ontario. Its area of jurisdiction includes 3,467 square kilometres; 2,506 on land and 961 water-based. The TRCA owns and operates a number of large and small dams and flood control structures. The two large dams that are the subject of this study, the G. Ross Lord dam and Claireville Dam, located in the Don River watershed and in the Humber River watershed respectively, are actively operated structures whose operational procedures are integrated with the TRCA Flood Forecasting and Warning program. The following map shows TRCA’s jurisdictional boundaries and the location of the Claireville and G. Ross Lord dams.