I’ve noticed that tributaries of the Mississippi and Ohio Rivers start just a few miles from the Great Lakes and their tributaries. Yet the Great Lakes themselves drain eastward to the St. Lawrence River.
Is there a major ridge of hills along the southern side of the Great Lakes that forms a sort of mini-Continental Divide? Or are the Great Lakes barely contained, and with just a little more erosion would start draining southwards?
Also, has anyone though of digging a canal from the Great Lakes to a navigable point in the Mississippi drainage system?
For a period of time ther was connection between Lake Erie to the Ohio River. The Miami Erie Canal. Some history here http://http://www.bright.net/~dietsch/grandlake/canal.htm
You might want to check the geography for Grand Lake St. Marys to Lake Erie. Grand Lake St Marys was the summit of the Canal with water from its west end flowing in route to the Mississipi and its east end into Lake Erie. A Topographical Map of the area would give you some indication of what it would take for at least Lake Erie to flow toward the Mississippi
Every river has its drainage, and adjacent rivers or systems are divided.
Even though the North American continental divide wends its way down through the Rocky Mountains, it doesn’t always follow the highest ridge line. There are places where the divide spreads out (a great desert basin where no water “excapes”) or becomes ambiguous (Two Ocean Creek supposedly hits a rock in the middle of the creek, and some the water goes to the Pacific, and the rest to the Caribbean). Even though the two drainages are “connected,” it would be tough to navigate a boat through it.
Major ridge? No. However, there is (or was) a continental divide of sorts. I grew up in a suburb of Chicago called Park Ridge. The ridge in question was once part of this continental divide. Rainfall on one side would drain into the Des Plaines River, which drains into the Illinois River, which drains into the Mississippi, which empties into the Gulf of Mexico. Water on the other side drains into the North Branch of the Chicago River, which drained into Lake Michigan and ultimately into the Atlantic.
This changed 100 years ago, when Chicago reversed the flow of the Chicago River for sanitary reasons. This was of course a major undertaking. That brings us neatly to your second question. Not only has such a canal been thought of, one was constructed 150 years ago, and later improved. The Chicago River now drains into that canal. It’s why Chicago grew as a city.
St. Louis sued to stop the project, as it didn’t want Chicago’s sewerage flowing into the Mississippi, but it lost. So every time I flush, it becomes part of St Louis’ water supply, not Detroit’s.
It’s called the Sanitary and Shipping Canal. The links in the chain are: Lake Michigan, the Chicago River, the canal, the Illinois River, the Mississippi.
There is indeed a sort of ridge across northern Ohio and Indiana that serves as a drainage divide. This is the terminal moraine (the pile of bulldozed stuff) left by the retreat of the glacier system that scraped out the hollows that became the Great Lakes. The moraine is heavily eroded and not that obvious anymore, and there may be some underlying rock structure that roughly coincides with it. I believe the Niagara Escarpment, roughly parallel to the southern shore of Lake Ontario, serves the same function in New York.
There was another canal across eastern Ohio, parts of which still exist (you can see some of it restored at Roscoe Village, near Coshocton). In fact, the city of Akron (Greek for “high spot”) was named for its location as the high point on the canal.
Like most other US canals, it was abandoned when the railroads came through. They couldn’t compete on either time or cost.
There have been at least four efforts to link the Great Lakes and the Mississipi with a fifth threatened every two years.
In addition to the canal at Chicago that several folks have mentioned and the Ohio-Erie canal mentioned by ElvisL1ves, (northern terminus was at Cleveland), there was a canal in Western Ohio that linked Lake Erie to the Ohio River by way of the Maumee and Miami Rivers (with several tributaries in between).
A fourth canal was begun from the St. Joseph River in Western Michigan/Indiana to the Tippecanoe and Wabash Rivers to the Ohio River. I cannot remember whether this canal was completed.
The two Ohio canals actually survived the railroads (at diminished capacity) until 1913. In that year, a major flood inundated large portions of the entire state of Ohio and wiped out much of the canal system, making it too expensive to repair. Sections of both canals kept on working for local use into the 1920’s.
Rep. James Trafficant submits a bill to congress every couple of years to build a Tombigbee-like, ecologically devastating canal from Ashtabula to Youngstown to re-open the Lake Erie-Ohio River connection. Between the costs and the environmental damage, (even the Army Corps of Engineers wants to avoid it), it never gets authorized.
As a California transplant living near Toledo, I would have to say that, to term the land seperating the Great Lakes watershed from the Ohio River watershed a ‘ridge’ would be straining the limits of English usage.
Most of Northern Ohio west of Cleveland and all of Northern/Central Indiana and Northern Illinois are essentially flat, varying by less than a couple hundred feet elevation. There is no particular geographical feature that determines where the drainage divide will end up. You might note that the headwaters of the St.Mary’s River (which becomes the Maumee River at its confluence with the St. Joseph River in Fort Wayne, IN) and the headwaters of the Wabash River (which flows generally westward until it turns south and heads into the Ohio River, acting as the Illinois/Indiana border for some distance) are within walking distance of each other in Central Western Ohio. Very close to both are the headwaters of the Miami River, which heads generally Southeast into the Ohio River. This triple watershed point one would think truly interesting to see. I’ve been there. It’s flat.
No one is going to confuse the Great Lakes/Gulf of Mexico divide for the Continental Divide anytime soon.
Growing up in Colorado, I’m used to 10,000+ ft. mountains defining where the water flows. Flying over the eastern US (yes, I consider the Great Lakes in the east, not “midwest”), I always wondered at the slight elevations determining watershed as definately as the Rocky Mountains.
In the area south of Cleveland, at least, there is a significant (by Midwestern standards) ridge which separates the watersheds, and there’s signs by the road labelling it as the (I believe) “Ohio divide”. I’m presuming that in the Chicago area, it’s a lot less significant, or the canal wouldn’t be practical.
The Chicago Sanitary and Ship Canal was begun in 1892 because the Chicagoans got tired of having to extend their fresh water intakes farther and farther out into Lake Michigan to avoid the pollution from the Chicago River. It paralleled the old Illinois and Michigan Canal that went to the Illinois River and thus to the Mississippi. So there is a drainage from the Great Lakes to the Mississipppi. From Navy Pier you can see the locks on the breakwater near the Coast Guard Station that keep Lake Michigan from draining into the Mississippi. (It has been a few years since I was there.) During the big Mississippi River drought (10 years ago?), Illinois was asked to open the locks and help fill the Mississippi River (and thus lower Lake Michigan). Illinois declined.
Given glacial rebound, in a few thousand years the Great Lakes will drain south naturally just as they did before the last Ice Age and up to the time that the retreating glaciers exposed the Straits of Mackinac.
What is the minimum (horizontal) distance from the Mississippi watershead to Lake Michigan? and
What is the minimum vertical distance from Lake Michigan’s surface level (580? feet) to the “ridge” that separates the lake from the Mississippi? In other words, how much did they have to “cut”? Since they made the Chicago river flow backwards, I assume there are no locks in the canal.
mipsman, I suspect that the drought to which you refer was 1988. My first glimpse of the Mighty Missorissippi came in that year, and it was a couple of trickles with a big sandbar in between… Heck, the Cuyahoga was a bigger river that year. Talk about dissappointment…
