River erosion cutting into Great Lakes'
water levels, report finds
By Hugh McDiarmid Jr.
Knight Ridder Newspapers
Published in the Kansas City Star January 24th, 2005
DETROIT - (KRT) - Lakes Michigan and Huron have permanently
lost a foot of water because of erosion in the St. Clair
River caused by dredging and other man-made meddling,
according to a study released Monday.
The decline will continue for the foreseeable future,
it warns, battering boaters, marinas, property owners
and the shipping industry struggling with water levels
at the bottom of historical cycles.
The low water was troublesome, but temporary, experts
had assured those struggling with dried-out boat canals.
Now, they're not so sure.
The reason: Erosion created gouges in the river bottom
up to 19 feet deep between 1970 and 2000, enlarging the
bottleneck at the bottom of Lake Huron where water drains
into the lower Great Lakes and Niagara Falls.
"It's like a drain hole at the bottom of a bathtub,"
said Rob Nairn, a principal with W.F. Baird & Associates
Coastal Engineers of Toronto, which conducted the study
for the Georgian Bay Association, a civic organization
representing about 4,200 Canadian families who live on
Georgian Bay islands and shores. "The drain hole
is getting bigger, and the water is going out faster.
It's something very alarming that no one has talked about
or reported until now."
Jim Weakley, president of the Lake Carriers' Association,
which represents domestic shipping companies, said he
had not seen the report Monday, but that a solution must
protect both commerce and the environment: "Any loss
of Great Lakes water is of concern for us. Each additional
inch allows between 250 and 270 tons of cargo" on
a larger freighter, he said.
Experts agree that dredging to deepen the St. Clair River
for commercial ships reduced the volume of water in Huron
and Michigan. Three such projects, the last one completed
in 1962, account for a 19-inch reduction in lake levels,
That was believed to be a one-time drop. Until now.
Monday's report found Lakes Michigan and Huron - considered
one body of water because they are connected at the Straits
of Mackinac - have lost an additional 12 inches since
1970 because of erosion that has gone undetected since
the 1962 dredging.
All told, the dredging and erosion has accounted for
a water loss from the lakes equivalent to 28 Lake St.
Clairs, according to the Baird report.
Because the extra water moves so quickly through Lake
St. Clair, the Detroit River and Lake Erie on its way
over Niagara Falls, it has not raised the levels of those
waters appreciably, Nairn said.
A modest resurgence in Great Lakes water levels during
the past two years is part of a natural cycle, but doesn't
mask the fact that the Huron/Michigan waters are still
a foot below where they would be without the erosion,
And the problem can't be explained by natural forces,
he said. Geologists say erosion in the St. Clair River
basin stopped between 2,000 and 3,000 years ago. But it
began again in the 1900s because of man-made factors including:
Dredging of the channel to 27 feet deep to accommodate
Erosion at the sites of sand mining that took place in
the river in early part of the 1900s.
Erosion control structures protecting beaches on lower
Lake Huron that deprive the St. Clair River of sediment
that normally would have washed into it and filled holes
in the river bottom.
The lakes' water loss went unnoticed because it was masked
by high water levels of the 1970s and 1980s, the report
suggests. But when Lake Huron receded in the 1990s and
early 2000s, residents of the archipelago of Canadian
islands in Georgian Bay suspected more than just the usual
30-year, high-to-low water levels cycles were in play.
"In recent years, we have had a significant number
of wetlands dry up on Georgian Bay, and the aquatic life
forced out onto steep granite shorelines," said Mary
Muter, the Georgian baykeeper who monitors the area's
They commissioned the study at a cost of about $163,000
to find out.
The results have alarmed scientists and policy-makers
across the region.
"We take it very seriously," said Dennis Schornack,
U.S. chair of the International Joint Commission, which
oversees boundary waters linking the United States and
Canada. "It's definitely of concern and the kind
of thing that is supposed to be part of an Upper Great
Lakes study that has not been funded yet by Congress."
Schornack said the potential for dredging-related trouble
was apparent as early as 1921, when a deepening of the
St. Clair River was approved by the IJC, with one condition:
that weirs - underwater barriers - be installed to slow
the velocity of water that would be increased by the channel
Those barriers were never built, said Schornack.
Underwater barriers or other methods to combat the erosion
need to be considered quickly, Nairn and a coalition of
environmental groups said Monday. The report did not suggest
The data also must be part of an ongoing bi national
study of the future of commercial navigation on the Great
Lakes, said the environmental groups.
"The Great Lakes are more than simply a navigation
corridor, and the time has come for the management of
the lakes to reflect that," said Jennifer Nalbone,
habitat and biodiversity coordinator for Great Lakes United,
a bi national lakes advocacy group.