Five diversions, like the Welland Canal between lakes Erie and Ontario, already have a hand in controlling Great Lakes water levels. Illustration: US Army Corps of Engineers
By Allison Bush, bushalli@msu.edu
Great Lakes Echo
June 9, 2009
Imagine turbines at the bottom of the St. Clair River that can control the height of the water on Lake Huron. What’s more, they can generate electricity.
Sound farfetched? They’re not, according to Craig Stow, a physical research scientist at the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory.
“Those sorts of things are technically feasible,” he said. “But it depends on funding and the will and outlook of the Great Lakes community. “
Turbines like these are exactly what one very vocal Lake Huron community wants to keep water levels from getting too high or too low. Property owners belonging to the Georgian Bay Association in the northeast corner of the lake are worried that erosion is causing the level of lakes Michigan and Huron to drop at alarming rates.
The Great Lakes water levels currently are controlled by several factors, including the Soo Locks, which regulate the outflow from Lake Superior, and five diversions that transfer water in and out of the Great Lakes basin, including the Welland Canal, which connects lakes Erie and Ontario. Lake Ontario is already completely regulated through various dams, locks and channel enlargements, with the lake levels being brought up and down in accordance with a particular schedule, Stow said.
“If we’re willing to spend the money and take the risk, we can substantially regulate these lakes,” he said.
But the current regulations do not have a large effect on either long-term lake level trends, and do not influence them significantly in the short term, according to Indiana’s Department of Natural Resources, or DNR. Rather, regulation primarily helps to alleviate lake level extremes.
In the upper Great Lakes, the effects of regulation can take up to 15 years to be seen, experts say.
And although it is feasible to control the amount of water flowing through the Great Lakes from an engineering standpoint, the amounts of rainfall and evaporation “are totally outside of human control,” said Roger Gauthier, a hydrologist at the Great Lakes Commission.
In addition, if the St. Clair River was regulated, it would mean that the Detroit and Niagara rivers would likely need to be regulated as well to mitigate the effects, Gauthier said.
Typically, regulated lakes are either fully or partially regulated, he said.
Full regulation requires the construction of a lock and dam system, and would interfere with the flow of commerce, Gauthier said. Partial regulation involves putting blocks, such as rock ledges, near the shore instead of in the middle of the shipping channel.
These ledges would offset the depth, and would have no interference if they were deeper than 30 feet, he said.
Lower water levels have significant economic impacts, Gauthier said. Many structures near the Great Lakes have wood cribs, which become exposed to air when the water levels drop.
“You can get a substantial amount of crumbling of structures,” Gauthier said. “And when you look at the 140 miles of (navigation structures) on the Great Lakes, that is profound.”
Lower water levels would also lead to a decreased amount of hydropower production and commercial navigation, he said. Therefore, it would make sense economically to regulate the water levels.
“But is it ecologically harmful? Likely. And is it socially acceptable? There would be a lot of debate,” Gauthier said.
Many of the organisms in the lakes are used to certain fluctuations, and changing the way lakes fluctuate over time could lead to severe consequences for these organisms, Stow said.
The Great Lakes are fairly recent, having only been around for about 10,000 years, he said. Their water levels have fluctuated constantly, and about 7,500 years ago, the water levels were so low that the lakes were not even connected.
This constant change in water levels makes it illogical to regulate the water levels for a particular group, because there will always be a trade-off, Stow said.
“Any time you put in something to regulate water levels, you set yourself up to make hard decisions,” he said. “When you hold water back in one lake, you’re keeping it from reaching another.”
But Mary Muter, a Georgian Bay Association Foundation board member, said water level controls are needed fast as climate change speeds evaporation, making low water levels an increasing concern.
“If we wait until climate change kicks in and lake levels drop below record levels, it will be hard to hold back water levels,” Muter said.