Author(s): Ian M. Knack; Fengbin Huang; Hung Tao Shen
Linked Author(s): Ian Knack, Hung Tao Shen
Keywords: No Keywords
Abstract: This paper presents a numerical model study on St. Marys River ice conditions for winter flow regulation to estimate the maximum allowable Lake Superior outflow. The increase in the maximum allowable outflow limit from Lake Superior will provide flexibility in maintaining more stable water level in the lower Great Lakes. The effect of increasing the wintertime flow limit in the Lower St. Marys River is examined using a two-dimensional river hydro-thermo-ice dynamics model. Simulations of freeze-up, undercover frazil transport and accumulation, and breakup ice jams with different combinations of water discharge and downstream water levels were simulated. The simulation results showed that with the high winter flow there will be significant increases in water levels in the area of the Little Rapids gauge and the US Slip gauge downstream of the US Locks due to breakup jams. The water level at the Cloverland Electric Cooperative (CEC) tailrace may increase above the allowable limit, which is the flood threshold at the Cloverland Electric Company Hydro Plant. A series of breakup simulations were made to determine the safe discharge to avoid ice jam flooding. These simulations show that the winter flow limit could be increased to 2690 m3/s from the current limit of 2410 m3/s given by Plan 1977-A, if flow regulation is managed with care by avoiding rapid changes in flow rate and water level to prevent premature ice cover breakup.
Year: 2012