Ships Run Aground as Great Lakes' Waters
Published July 3, 2006
TORONTO, Ontario (Reuters) -- Several large vessels have
run aground on Michigan's Saginaw River this shipping
season, caught in shallow waters a few miles from Lake
The river port is as shallow as 13 feet in a passage
that is supposed to be 22 feet deep, a sign of low water
levels in North America's five Great Lakes -- Superior,
Michigan, Huron, Erie, and Ontario.
Water levels declined in 1998 and have remained low,
forcing ships to take on lighter loads and sparking concern
about shorelines and wetlands in the Great Lakes, the
world's largest supply of freshwater and a major commercial
shipping route for Canada and the United States. Iron
ore and grain are among the biggest cargoes shipped on
"It's a pretty different mindset to come off 30
years of above-average water levels and to suddenly, since
the late 1990s, have below-average levels," said
Scott Thieme, chief of the U.S. Army Corps of Engineers'
Great Lakes Hydraulics and Hydrology Office in Detroit.
Lakes Huron and Michigan, where water levels have declined
the most, are down about 3 feet from 1997 and about 20
inches from their 140-year average, according to the U.S.
National Oceanic and Atmospheric Administration's Great
Lakes Environmental Research Laboratory.
When homeowners on Lake Huron's Georgian Bay noticed
wetlands were drying up, the Georgian Bay Association
funded a $223,000 report that last year concluded shoreline
alterations such as dredging and erosion in the St. Clair
River, at the bottom of the lake, were responsible.
In partial response, U.S. and Canadian governments approved
funding for a $14.6 million study of the upper Great Lakes
by the International Joint Commission, which resolves
border disputes and was denied funds for a similar study
Depending on what it finds, the commission could recommend
changes to the amount of water that flows out of Lake
Superior, the first and largest in the chain of lakes.
'Taking a straw and widening it'
Water levels in the Great Lakes have always fluctuated,
but experts point to climate change, dredging, private
shoreline alterations and even lingering effects of glaciers
to explain the latest changes -- the decline of Lake Huron
and slightly higher water levels in Lake Erie, into which
The most controversial of several dredging projects was
in 1962, when the U.S. Army Corps of Engineers deepened
the St. Clair River channel by 2 feet to accommodate commercial
"When they dredge a river, it's like taking a straw
and widening it," said hydrologist Cynthia Sellinger,
who helped plan the upper Great Lakes study, which begins
U.S. and Canadian governments approved the 1960s dredging
on condition that submerged sills be built to compensate
for water lost from Lake Huron, and they started a series
But by the time the studies were completed in the 1970s,
water levels in Lakes Huron and Michigan were at record
highs, and no one wanted sills that would raise levels
Experts are unsure why water levels in the upper lakes
rose soon after the St. Clair River dredging. But they
say that major climatic events usually coincide with changes
in water levels.
The 1930s Dust Bowl drought coincided with then-record
low levels in the Great Lakes. And the most recent decline
was in 1997, when a strong El Nino brought warm, dry temperatures
to North America, Sellinger said.
In addition, above-average temperatures since 1998 mean
less ice forms on the Great Lakes and the rivers that
flow into it, and more water evaporates away, Sellinger
And then there is something called post-glacial rebound,
or the slow rise of the earth's crust, that could partly
explain declining water levels in Lakes Huron and Michigan.
"The area around Georgian Bay (Lake Huron) is rising
faster than the area around Lake Erie so it may be that
the land has just tilted and more water is flowing out,"
A foot drop in 9 years
For every inch water levels go down, ships bound for destinations
outside North America forfeit about $8,400 in freight
revenue, said Dennis Mahoney, president of the United
States Great Lakes Shipping Association.
Saginaw and other ports have done emergency dredging
to accommodate ships and barges that can be hundreds of
But Lake Superior's largest American ships carried 3,000
fewer short tons of cargo last year than in 1997, when
water levels were 12 inches higher, according to the Lake
"Obviously water levels are crucially important
to this industry, and we have been in a period of decline,"
said Glen Nekvasil, vice president of corporate communications
for the association.
"When you're not utilizing your full vessel capacity
you can't give your customer the best freight rate."
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