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Does Lake Huron need a rubber bladder?

This Magazine Staff

Water levels in Lake Huron have been low for a while. Really low. Docks are now on dry land, harbours are having to be dredged, cottagers are getting ornery. In fact, Huron and Michigan have been at “critical alert” level since 2000. One group, the Georgian Bay Association, is championing the theory that the water is rushing out the St. Clair River thanks to U.S. Army Corps of Engineers dredging.
But is it? And will an inflatable rubber bladder be the answer?

I’m spending a Saturday morning, one sadly short on coffee, on the Pride of Michigan. Mary Muter from the GBA is on board, as is Krish, an Environment Canada researcher. There’s also a retired NOAA hydrologist, someone from the U.S. Army Corps of Engineers, and a policy advisor from the IJC.
Water flows out of Lake Huron through the St. Clair River and into Lake Erie. There’s a theory, which Mary explains, that dredging disturbed the river bottom, which is now being scoured out by water rushing into Lake Erie, effectively opening the drain.
A screen shows the river bottom, being filmed by a camera we’re towing behind the boat. It’s mostly pebbles and stones 5 cm or more in diameter. I ask Krish, the EC researcher beside me, if the river’s flow could shift that. “No,” he replies. At least, not without some disturbance. The river can only carry sand — debris less than 1.3 mm in diameter. And dredging could provide that disturbance, Mary tells me as we continue up the river. Everyone agrees that cutting navigation channels through the river and extracting sand from its bottom in the 1800s has lowered Lake Huron by 14 inches. But the debate is whether dredging is letting debris flush out, futher lowering the river bottom.
There’s a “scour hole” about 60 feet deep at one bend in the river. It surrounds the wreck of the Sidney Smith, a tanker that went down in 1972. As water rushed around the wreck, it does seem to have carried away a lot of riverbed material. Still, one hole shouldn’t affect lake levels, since the river bottom on the other side of it is still high.
But that hole may be at a “critical juncture” in the river, Mary says. And that’s why Krish is here — to figure out just what is happening on the river bottom. The scouring theory has a lot of sceptics, and an IJC study won’t be completed for another year. One solution to the problem, if it is riverbed scouring, would be to place an inflatable bladder in the hole, says Mary. Then you could pump it up with water and reduce flow at critical times.
But this idea has plenty of opponents. John Nevin, a policy advisor with the IJC, seems to be one of them. Lake level controls are controversial in the Great Lakes, and the IJC has been looking at ways to make flows more natural, particularly in Lake Ontario. Many lakes are highly regulated: Superior through locks, Erie through the Welland Canal, and Ontario through the Niagara Falls power diversion. The bladder would be one more step toward five-lake regulation, he says (he’s on the boat, too).
“You can’t have someone twiddling at the dials to meet one group’s or two groups’ — or one very vocal group’s — needs. The lakes need to fluctuate more naturally,” he says.
However, as Mary points out, critically low water levels are expensive. The U.S. is already looking at spending $100 million to dredge ports, and Ontario marina operators have asked for a similar sum. It’s a problem we can’t wait to solve, she says, though completing the study first is important. But she does seem quite convinced that the St. Clair River is the problem. And that the bladder is the way to go.
Others disagree. And with cause, as there are a lot of other factors at play.
Lack of winter ice might be increasing evaporation. Climate change is increasing wind speeds and both water and air temperatures, which could also speed evaporation. Lake Superior’s water levels are low because of low precipitation. Lakes Huron and Michigan were at rather high levels in the 1960s, 70s and 80s when infrastructure such as docks was built. Even the Earth itself is against the lake — isostatic rebound is raising Lake Superior, Lake Huron and much of Lake Michigan, very slowly making them shallower (not enough to account for these short-term fluctuations, but over a century, it can mean a water levels going down by a foot).
The problem might not be Lake Huron’s alone. And while tossing a bladder in the St. Clair River might help in the short-term (and I didn’t hear a compelling argument that it will), it won’t solve what is rapidly shaping up to be a problem throughout the Great Lakes Basin.

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