Managing lake levels

4/23/2012

A new study concludes there is no urgent need for new dams or other man-made structures to manipulate Great Lakes water levels more than humans already do.

The five-year study involved more than 200 scientists and engineers in the United States and Canada. They reported to the International Joint Commission, which helps the two countries resolve boundary-water issues.

Proposed engineering “fixes” for lake-level issues could cost as much as $8 billion, without a clear understanding of whether their benefits would outweigh the risks. Water levels have been down for more than a decade, but future declines attributable to climate change may not be as dramatic as was earlier thought.

The lakes typically undergo natural fluctuations in water levels every 30 years. The report’s findings are a reminder that nothing about water flow is ever as simple as it sounds, and that many well-intended projects have gone awry.

Humans have manipulated the Great Lakes for decades. A massive diversion of Lake Michigan in Chicago has reversed the flow of water out of its basin since the early 1900s, to reduce sewage-induced disease. That has lowered Lakes Michigan and Huron by two inches.

Shipping locks in Sault Ste. Marie and upstate New York affect water flow. So does the Welland Canal, which was built to enable ships to get around Niagara Falls. These projects suggest that everything need not be left up to nature, but neither is there a reason for undue haste.

The IJC historically has shown a respect for science and a willingness to take unpopular positions to protect the Great Lakes. The U.S. State Department should encourage the commission to continue to monitor lake levels.

The Georgian Bay Association, a Canadian citizens group, helped force the issue of lake levels in 2007. A consultant it hired determined that the St. Clair River near Detroit was losing 2.5 billion gallons of water a day, three times more than estimates.

One theory cited scarring to the riverbed by a U.S. Army Corps of Engineers dredging project between 1956 and 1962 to accommodate shipping. The group pushed for a giant, inflatable synthetic bladder to help manage the St. Clair River’s water flow, but that proposal apparently is off the table.

The IJC’s study board makes a plausible case that now is not the best time to install more man-made controls on the Great Lakes. With luck, they won’t ever be necessary. But in the meantime, the discussion needs to continue.