Part 1At least 150 years of rhythmic pulses in Lake Michigan's water levels appear to have shifted abruptly with loss of winter ice.
Part 2Every time dredging widened and deepened the hole at the bottom of the lakes, the federal government was supposed to engineer a fix to maintain water levels - but it never did.
An unprecedented spike in evaporation is not the only reason Lakes Michigan and Huron hit a record low this winter.
If you think of the two lakes that sprawl across 45, 000 square miles as one colossal bathtub, then the drain is a mere 800-foot-wide gap at the southern tip of Lake Huron. This is the headwaters of the St. Clair River, a torrent that, in places, runs up to 70 feet deep.
Lakes Michigan and Huron are actually one body of water — two lobes of the world's largest freshwater lake — and this river pulls their waters southward toward Lake Erie, over Niagara Falls and, ultimately, out to the Atlantic Ocean.
This makes the St. Clair River one of the most ecologically sensitive and hydrologically critical places in all the Great Lakes.
It is also among the most ravaged.
Humans have been expanding the size of this drain hole for more than a century, beginning in the 1850s, when shallow choke points in the channel were scraped away so schooners could sail up from Lake Erie.
In the 1890s, profiteers began mining the riverbed for its thick deposits of sand and gravel, an estimated 3.5 million cubic yards of which were hauled off between 1908 and 1925 alone — enough material to fill some 300, 000 dump trucks.
Even with the measurement tools available at the time, this had a noticeable impact on lake levels, so in 1926 government officials put an end to the mining.
Yet dredging continued into the 1960s to carve ever-deeper navigation channels for ever-bigger freighters. The engineers doing the digging knew all along their work was dropping the long-term average levels of Michigan and Huron.
That's why each time the government approved a major dredging project in the 20th century it came with a plan to compensate for lake water lost. The idea was to build dam-like structures in strategic areas on the river bottom to slow the outflow yet maintain a channel deep enough to keep the Great Lakes freighter business afloat.
But that work was not done in the early 1900s when the St. Clair's shipping channel was deepened to 22 feet, or in the 1930s when it was lowered to 25 feet. And it wasn't done again in the 1960s, when the channel went to 27 feet.
The federal government's official toll for how much the expanded river channel permanently lowered the lakes is between 14 and 18 inches — enough fresh water flushed out to the ocean to turn an expanse of land the size of Wisconsin into a wading pool.
In the mid-1960s, Frank Quinn was a young hydrologist with the U.S. Army Corps of Engineers in Detroit when he was dispatched down South to work on a plan to patch the St. Clair's enlarged drain hole and bring the water back where it belonged.
An Army Corps team had built a concrete model of the southern tip of Lake Huron flowing into the upper reaches of the St. Clair River in a sprawling warehouse at the agency's research center outside Vicksburg, Miss. Bigger than a basketball court, the model was a precisely shrunken replica of the river channel. It also reproduced its bathymetry so the engineers could figure out where to put the water-slowing structures.
U.S. Army Corps of EngineersThis photo shows a researcher using a giant model to study how to restore natural flows on the St. Clair River following a 1962 dredging project. The Army Corps scrapped the plans after high water returned on Lakes Michigan and Huron. VIEW ALL PHOTOS >
The crew-cut men also toyed with a 7-foot-long remote controlled freighter, just to make sure they got things right — for the lakes and for the shipping industry.
"They did it right to scale, and then put water down the river to see if it would work and how it would work, " said Quinn, now retired from the National Oceanic and Atmospheric Administration.
"It worked just fine."
But the job was never done.
"What happened then was, starting in about 1966 or so, we started getting a lot of rain and the water levels went up, " said Quinn.
As the lake levels climbed back toward their long-term average and then beyond, interest in the project evaporated
"The water levels were high enough that nobody wanted them higher, " said Quinn.
So the scale model of the river was junked along with the plans to restore the riverbed.
Property values plummet, tooWater levels in the Great Lakes, remarkably stable for generations, are headed out of whack. Can a solution be engineered to prevent more water from being lost through the St. Clair River? WATCH MOTION GRAPHIC >
Lakes Michigan and Huron have now gone a record 14 years without reaching their long-term average level, and they set a new record low in January.
The water level has since rebounded a bit with the exceptionally wet spring, but it remains about a foot and a half below its average for this time of year. The situation has created havoc for everything from coal boat captains to marina operators to shoreline property owners from Milwaukee's northern suburbs all the way to Georgian Bay at the top of Lake Huron.
Georgian Bay's location less than three hours north of Toronto has made it a prime place for vacation homes, much like Door County is to Milwaukee and Chicago.
It is a place hit particularly hard by the low water because areas of its shoreline are so gently sloping that when the water is down, it doesn't just dip in front of some docks and wetlands. It disappears.
Michael McCartney bought a plot on a 200-acre island in Georgian Bay almost 25 years ago, when the wild blue waters were chest-deep at the end of his dock.
His link to the outside world was a 22-foot yellow Sea Ray motorboat, which he used to ferry building materials from the mainland as he and his wife and children painstakingly built their own home.
Michael McCartney bought a plot on a 200-acre island in Canada's Georgian Bay almost 25 years ago, when the water was chest-deep at the end of his dock.
Then the water levels started to drop and the McCartneys extended the dock into deeper water. The water kept dropping. McCartney bought a smaller boat, then a smaller boat, and then a smaller one yet.