Are the Great Lakes shrinking?

The Great Lakes have lost water because of navigational dredging in the St. Clair River — 21 inches for Lakes Michigan and Huron, according to an International Joint Commission (IJC) study released this week. But are they continuing to decline? Is the opening in the river widening, draining increasing amounts of water from the upper Great Lakes? 

Lake St. Clair

Lake St. Clair

Those are the questions the study by the IJC’s “International Upper Great Lakes Study Board” was supposed to lay to rest. But it fell far short. Sure, the study concluded that all the erosion was in the past, that the river was no longer widening, and so lake levels would not be affected in the future. The problem is that the study was deeply flawed, ignoring mounds of data and scientific studies that contradicted its conclusions. 

And this study matters in a very practical way. It will be used by the IJC to determine whether remedial measures should be taken in the St. Clair River – perhaps even structures built – to return the lake levels and flows to a more natural state. 

With climate change predicted to lower the levels of Lakes Michigan and Huron by as much as 3 feet in the next century and pressures to manage those levels increasing, those decisions are critical.

The Great Lakes deserve better than this study. 

National Wildlife Federation’s Melinda Koslow and Dr. Mike Murray, who have been working to improve the study for over a year, provided more detail about the study’s flaws in this news statement released Tuesday; I’ve reprised that below. And for an excellent analysis, check out Dan Egan’s piece in the Milawaukee Journal Sentinel

For immediate release:
December 15, 2009


Despite multiple responses and scientific studies questioning findings, a report released today by the International Upper Great Lakes Study Board, a U.S.-Canada expert panel established by the International Joint Commission, refused to change its controversial conclusions about water losses through the St. Clair River. 

Their final report again concludes that there is no ongoing erosion in the St. Clair River and therefore an examination of possible remedial measures is not necessary. 

This conclusion is a result of a multi-million dollar publicly funded study, and the best opportunity to address the issue of unnatural water losses from Lakes Michigan and Huron. 

“Dredging and erosion in the St. Clair River has had a massive impact on Great Lakes water levels, and there’s substantial evidence that this erosion is continuing,” said Melinda Koslow, NWF’s Great Lakes Climate Safeguarding Manager. “But the study ignores or dismisses that evidence in concluding that erosion has stopped and no action should be taken. That ‘no action’ conclusion puts the Great Lakes at further risk.” 

NWF identified a number of major problems with the Study Board’s report, including: 

  • Lack of acknowledgment of findings on potential erosion and other changes in the sediment bed of the river, and downplaying of significant changes in bathymetry (bottom depth) between 1971 and 2008.
  • Failure to calculate or estimate flow of water losses through the River.
  • Actively neglecting scientific studies that contradicted their conclusions.

“At a minimum, these findings raise the possibility of ongoing erosion of the St. Clair River bed over the past four decades, but it is not clear that the full Study Board has been open to this possibility,” said Michael Murray, Ph.D., Staff Scientist with NWF’s Great Lakes office. 

“The way the Study was conducted makes us think that the results were pre-determined. The Study authors blocked the kind of transparency a public process normally encounters,” Koslow added. 

Activities of the Study Board that contributed to a loss of transparency included: 

  • Delayed release of scientific reports related to the Study.
  • Delayed release of public comments and Board responses until today.
  • Subjective summarizing of public comments.

The Study Board insisted in published documents that, “Generally, it appeared that the public found that Study outcomes were acceptable with respect to the mandate, resulted from an open and unbiased process and reflected sound science.” But in comments during the public hearing period and release today, numerous experts and organizations questioned and criticized the study’s conclusions. For example: 

  • An engineer from Canada raised multiple points two of which are, “There appears to be a built in resentment towards Canadian initiative of scientific analysis and there appears to be a decided dictatorial style and not true international discussion and working together.”
  • Great Lakes United states in their comments, “Even if there is not on‐going erosion since 2000 (and this is debatable), it does not mean that the system is being restored to conditions similar to those prior to the changes that have happened between 1971 and 2000. There is still substantially more water going through the St. Clair River everyday now than there was prior to 1971. This fact on its own is sufficient to say that remedial options should be explored.”
  • In 9 signed petitions from a public meeting in Cleveland, concerned stakeholders raised the transparency issue, the erosion issue, and the issue of the Board admitting disregard of certain scientific reports.

NWF also reviewed scientific findings related to erosion. The findings on the river morphology include the following: “Best et al. concluded that major scour has occurred at the outside of the first bend in the St Clair River. Deposition is associated with sediment ‘lobes’ or ‘bars’ in the main channel, and a large bar located in a region of recirculating flow near the casino on the Canadian side of the river. Also, flow transverse bedforms cover much of the bed in the St Clair River and some parts of Lake Huron, and appear weakly mobile. The sediment ‘lobes’ in the channel near the casino are mobile and appear to have migrated downstream by a maximum of about 20 m in the past year (2007-2008). 

Furthermore, velocity profiles assessed by another study indicate shear stresses sufficient to move sediment particles on the order of 2-10 mm. 

This may not constitute “general bed erosion” as described in the Report key points, but the potential for sediment movement over broad areas is definitely there, including when considering additional potential from ship propeller-induced movement.” 

Even though the upper lake levels have rebounded from record or near record lows two years ago, this is still not time for complacency. 

“With milder winters (and increased evaporation) likely in climate change scenarios, we could see significant declines in upper lakes water levels in the coming decades, so it is important to accurately assess to what extent Lakes Michigan and Huron are already lower than they otherwise would be because of other human actions,” said Koslow. 

“We have the experts together that could start to examine remediation options. This is the time to address this water loss issue,” she added.


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