The International Great Lakes Study Board has recommended changes to the outflows from Lake Superior to downstream lakes.

In their final report to the International Joint Commission (IJC), the panel of experts from Canada and the United States that carried out the five-year, $17.6-million study say "a new more robust regulation plan for outflows from Lake Superior would provide important benefits, especially to the environment."

The report notes that control structures at the outlet of Lake Superior on the St. Marys River, is the only location in the entire Great Lakes basin upstream from Niagara Falls where water levels can be affected by regulation.

The study was launched by the IJC in 2007 to review the regulation of Lake Superior outflows and to assess the need for improvements to address both changing needs and a changing climate.

A spokesperson for the IJC said that prior to taking any action the commission will hold public hearings beginning in July.

The study board believes the recommended regulation would be superior to the one in place since 1990, especially under conditions of lower water supplies.

"For example," the report says, "if conditions are significantly drier, the new plan does a better job of preserving Lake Superior water levels while taking into account downstream lakes. In addition, under dry conditions, the new plan avoids the serious adverse effects on the spawning habitat of sturgeon in the St. Marys River.

"Compared to the existing plan, month-to-month changes will generally be smaller under the new plan, giving the St. Marys River a more natural flow relationship to Lake Superior levels. This is an important factor in sustaining ecosystem health in the river."

The report says a new regulation "will provide modest additional benefits for commercial navigation, hydroelectric generation and coastal interests, under both wetter and drier water supply conditions.

"Most importantly, under very dry conditions, commercial navigation through the Soo Locks and power generation would not be threatened with closure under the improved plan, as it now is. In addition, the rules will be much less complex, making it easier to manage, maintain and adapt to a changing climate."

The study board's first report, Impacts on Upper Great Lakes Water Levels: St. Clair River, addressed changes in the St. Clair River. It was submitted to the IJC in December 2009.

The final report says that researchers found that restoration structures (such as "speed bumps" in the St. Clair River) designed to raise Lake Michigan- Huron water levels would result in adverse effects on certain key interests.

"Moreover," the report adds, "the potential for multi-lake reg-u l at i o n (additional control points on the St. Clair and Niagara rivers) to address extreme water levels is limited by uncertainty of future water supplies, environmental concerns and institutional requirements.

"Not surprisingly," the report says, "public concerns about water levels in the upper Great Lakes differ considerably depending on geographic location.

"For example, many residents of the Georgian Bay region of Ontario supported construction of new structures to provide for restoration or multi-lake regulation.

"In contrast, many residents of Lake Michigan (and other areas) expressed concern about potential damages of higher water levels and those living on the St. Clair River and downstream opposed new structures because of the possibility of negative environmental impacts, among other reasons."

The report emphasizes that changing water levels can have significant effects on the lives of the more than 25 million people who live and work in the upper Great Lakes region.

"Under the Boundary Waters Treaty of 1909, domestic and sanitary water uses, navigation, and power and irrigation are given order of precedence. These uses must be taken into account in the development of regulation plans.

"Today, it is recognized that other interests have rights under the Treaty, consistent with the International Joint Commission's balancing principle -providing benefits or relief to interests affected by water levels and flows without causing undue detriment to other interests.

"With this in mind," the report says, "the study takes into consideration the interests of ecosystems, coastal zone uses and recreational boating and tourism to its analysis of Lake Superior regulation and uncertainty in future upper Great Lakes water levels.

"In addition, the Study recognized that First Nations in Canada, Native Americans and Métis represent an important perspective in the upper Great Lakes."

For thousands of years, and continuing into the present, many Native American communities and First Nations have relied on the natural resources of the Great Lakes to meet their economic, cultural and spiritual needs.

The report also examined the impacts of climate change on the upper Great Lakes.

Using what it called "cutting edge scientific information," the study found that changes in lake levels may not be as extreme over the next 30 years as previous studies have predicted.

"This finding reflects a trend of increasing evaporation, likely due to lack of ice cover, and increasing water temperatures and wind speeds, with the resulting reduction in water supplies largely offset by increased precipitation."

The report said projections suggest that lake levels will remain within a relatively narrow historical range with lower levels likely though higher levels are possible at times.

The study's authors say the project brought together some 200 scientists, engineers, planners and technical experts from both the United States and Canada, produced more than 100 separate technical reports that stand as a legacy for future researchers. It adds that their work has benefited from an unprecedented level of independent expert peer review.

The final report recommends that the IJC:

* Approve Lake Superior Regulation Plan 2012 as the new plan for regulating Lake Superior outflow;

* Seek to improve scientific understanding of hydro-climatic processes and impacts on future Great Lakes water levels as part of a continuous, coordinated bi-national effort that includes strengthened modelling and enhanced data collection; and,

* Adopt an adaptive management strategy to address future extreme water levels and establish a Great Lakes-St. Lawrence River Levels Advisory Board to help administer the strategy.

In addition, the report says further study of multi-lake regulation in the Great Lakes-St. Lawrence system should not be pursued at this time.

The full report and a summary version are available on the International Upper Great Lakes Study website.