The scope of the International Upper Great Lakes Study has changed, as scientists investigate how raising the water levels of Lakes Michigan and Huron could possibly affect interests in the basin.

Members of a Study Board that's directing the project recently responded to additional guidance from the International Joint Commission that spells out the exploratory investigation. Rather than a change from previous guidance, the IJC is directing the Study Board to look further into options for water restoration based on calls from the public for more study of the issue, says Dr. Syed Moin, the study's Canadian co-manager.

In December 2009, the Study Board recommended that measures to remediate the increased water-carrying capacity of the St. Clair River since 1962 not be undertaken “at this time,” Moin explained. This was based on the scientific finding that the increased capacity was small and had been apparently declining since 2000.

The Study Board determined that it would be more prudent to look at past changes along with the impacts from climate change before making their final recommendation in Phase 2 of the Study regarding Lake Superior regulation. An integral part of this analysis is determining how all interests might be affected by any of the recommendations.

Under the additional IJC guidance, the Study Board will examine the effects of five restoration scenarios as well as the methods for raising the levels of Michigan and Huron by 0 centimetres (no change), 10 centimetres (restoring the change since 1962 as measured by Phase 1 of the Study), 25 centimetres (restoration of 1960-62 dredging through the present), 40 centimetres (restoring the impacts of the 1930 dredging through today) and 50 centimetres (remediating for changes since the late 19th century).

“This will be addressed through the modelling, or mathematical, approach,” Moin said. “We will model the entire system and come up with resulting water levels and flows. Then, at an exploratory level, we will evaluate the impact of various water level changes on coastal ecosystems, property owners, navigation, hydropower, recreational boating and municipal and industrial water users -- all the critical interests both upstream and downstream."

The result of that first approach will be a series of maps and tables, showing areas that would experience positive impacts and areas that would see negative impacts from regulating flows in the St. Clair River to raise levels in Lake Michigan and Huron.

“That's what I call the easier part,” Moin explained. “The tougher part, and the second approach, is what physical structures would be required to accomplish that level of restoration?”

Scientists will review literature on the subject and look at options that have been proposed over the last 30-40 years for physical structures -- things like weirs, spur dikes, power-generating turbines, baffles and inflatable dams, Moin said.

Under the latest guidance, the Study Board also will also examine possible expansion of the International Lake Superior Board of Control or the creation of a new board to address issues related to the Lake Huron and Michigan.

The full water restoration analysis has yet to be done, Moin said, but previous studies suggest that raising the water levels of Lakes Michigan and Huron by any significant amount would result in major impacts, both upstream and downstream, and especially in the sensitive, shallow ecosystem of Lake St. Clair. The technical report on this issue is expected to be submitted for peer review in the spring and is slated for completion by early summer.