Improving Lake Superior Outflow Regulation - Phase 2 of the International Upper Great Lakes Study

摘要

Over the last three years, hundreds of investigators from U.S. and Canadian government and non-government agencies and universities around the Great Lakes have been studying the possible factors responsible for recent declining upper Great Lakes levels. They have concluded that over the last four decades, the conveyance of the St. Clair River, the river connecting Lake Michigan-Huron to Lake Erie, has changed due to man-made factors like dredging but also due to natural factors like a major ice jam that occurred in 1984. However, they also determined that the declining lake levels were due primarily to climatic variability and glacial isostatic rebound. As such, remedial structural measures in the St. Clair River were not warranted. With that important phase of investigations ending, the International Upper Great Lakes Study (IUGLS) is shifting its focus to investigations toward formulating alternative plans for Lake Superior outflow regulation with the goal of providing benefits to existing and emerging interests. The Lake Superior Regulation Task Team has organized a team of performance indicator, integration and advisory technical work groups to formulate and evaluate alternatives to the present plan for Lake Superior regulation, Plan 1977-A, which has been in use since 1990. It already has been determined that improvements based on historic supplies will be small. However, considering more extreme conditions that could result under climate change-type scenarios, improvements may be identified, particularly when considering adaptive management. Connecting channel structural changes will also be considered. This paper describes the studies that are planned and the strategies that are being envisioned that will lead to alternative regulation plans by Study completion in the Spring of 2012.