Can multi-lake regulation address extremes?
- The primary mandate of the IUGLS was to provide recommendations to the IJC on how to better manage upper Great Lakes water levels and flows to the benefit of all interests served by the upper Great Lakes system. In turning to the question of Lake Superior regulation, the Study Board recognized early on that it would be difficult to design a single regulation plan that would be optimal for all future conditions, given the high level of uncertainty associated with future hydrological conditions of the basin. Moreover, it became apparent that extreme water levels equalling or exceeding the range of levels observed in the past could be experienced in the future, and that Lake Superior regulation alone could do little to reduce the risk posed by such extremes, particularly downstream of Lake Superior. The Study Board concluded that to more fully address changing water levels in the upper Great Lakes basin, there was a need to look beyond the existing system of Great Lakes regulation, and consider alternative approaches for managing and adapting to uncertain future conditions. One such option is multi-lake regulation – the possibility of operating regulation structures to control Great Lakes water levels and flows, within certain limits, to benefit the Great Lakes - St. Lawrence River system as a whole. In theory, this could be achieved either by using the existing two structures on the St. Marys and St. Lawrence rivers, with modified regulation rules that consider the entire state of the system, or by combining modified regulation rules at the existing structures with new control structures at one or more of the additional Great Lakes connecting channels, such as the St. Clair, Detroit and Niagara rivers.