Did they or didn’t they?
Results are in from a two-year, three-and-a-half
million-dollar study to determine whether the US Army Corps of Engineers
inadvertently caused a drop in water levels of Lake Huron and Lake Michigan.
One theory—put forward by Canadian property owners who
noticed a permanent 4-inch drop in the lakes’ water levels—is that the Corps of
Engineers “unplugged” the lakes during a dredging project in the 1960s by
scraping away an erosion-proof layer of the St. Clair riverbed. The two lakes
are connected, and the St. Clair River is their main outflow. A Canadian
homeowners association wants the US and Canadian governments—both of which
funded the study—to build a dam on the river to restore the lake levels.
Although the report, and the Corps of Engineers itself,
acknowledge that earlier dredging caused some changes, the report concludes that
it was an ice jam in the 1980s that carved the riverbed deeper and led to the
4-inch drop in lake levels. It says the riverbed is no longer eroding.
Overall, it’s generally agreed, the lake levels are 20 inches
lower than they were nearly a century ago, and the first 16-inch loss was likely
caused by dredging operations in the river to improve commercial navigation. A
spokesman for the Corps of Engineers points out that this is a good deal,
though, because during the 1980s, when water levels were higher than they are
now, flooding and erosion would have been much worse had the lakes not already
lost some depth.
You can see articles on the recently released here here
and here