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- Input Projects
- Plan Formulation and Evaluation Strategy
Maximum Winter Flows in the St. Marys River to Avoid Ice Jams & Flooding
- The maximum allowable flow to avoid St. Marys River ice jam flooding was examined using a two-dimensional hydro-thermo-ice dynamics model. Simulations of freeze-up, undercover frazil transport and accumulation, and ice breakup jams with selected flows and downstream water levels were simulated. In high flow cases, excess water was routed through the Compensating Works. With higher winter flows, there were significant increases in water levels at Little Rapids and US Slip gauges. The level at the Cloverland plant may increase above the flood threshold of 177.77 m (i.e. top of the tailrace tunnel). Breakup simulations were run to determine the safe discharge for breakup. Simulations showed that the winter flow limit could be increased to 2690 m3/s (from 2410 m3/s) if flow regulation is managed with care (avoiding rapid changes in flow to prevent premature ice cover breakup, which could result in thick ice jams & flooding).
- Additional Data and Information
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- Supporting Content
- Main Topics
- - Lake Superior Regulation
- Questions We Asked
- - Can a regulation plan be designed to perform better than Plan 1977A?
- - What are the limits of regulation?