Jan 29
The Waterways We Love - The Illinois Waterway & Lake Michigan to the Mississippi (Part 9)
- Richard Crowder
- Apr 3
- 8 min read
The Illinois Waterway consists of 336 miles (541 km) of navigable water and is the direct link between the Great Lakes and the Gulf of Mexico via the Mississippi River. To accomplish this, it utilizes four distinct and separately named waterways: the Chicago River, the Chicago Sanitary and Ship Canal, the Des Plaines River, and the Illinois River.
You may however wish to choose the Calumet River and Cal-Sag (Calumet-Saganashkee) Channel located just south of the Chicago River in the above route when exiting Lake Michigan. They merge a few miles inland. There are a total of eight locks along the system from Lake Michigan to the Mississippi River to account for the 163-foot (50 m) drop in elevation between the two bodies of water.
In the mid-1800s, the Illinois and Michigan (I & M) Canal was opened to connect Lake Michigan with the Illinois River, a distance of 96 miles (154 km). It primarily used experienced labour that had just completed the building of the Erie Canal. While the I & M Canal was only 60 feet (18 m) wide and 6- feet (1.8 m) deep, it opened up the US Midwest agricultural heartland to the Atlantic coast and overseas markets. Its 17 locks handled the elevation difference of 140 feet (43 m) from Lake Michigan down to the Illinois River.
As with almost every village, town, and city in the 1800s and prior, if a river was handy to it, and the larger the better, it was used as the dumping ground for human and industrial waste. This was certainly true of both branches of the Chicago River as it flowed gently into Lake Michigan. But toward the end of the century, and worried about this effluent reaching Chicago’s drinking water intake pipe not far offshore, it was realized the I & M Canal was too shallow and too narrow to handle the increasing size of barges. Local politicians decided a new canal was needed.
As a bit of background, a low ridge of north-south land about 12 miles (20 km) inland on the west side of Lake Michigan and parallel to the shoreline of the lake, is the low height of land that creates the divide between the westbound watershed of the upper Mississippi River from the eastbound watershed of Lake Michigan. Because of this, the north and south branches of the Chicago River run parallel and very close to the shoreline. They join just inland of Chicago’s Navy Pier and originally and drained into Lake Michigan at that point.
This ridge of land between the two watersheds was dug through to create the original I & M Canal, but keeping sufficient water in the canal through the area was a constant challenge. When a new canal was proposed, solving this dilemma was an utmost priority since this new canal would need even more water. The United States Army Corps of Engineers (USACE) was assigned the task to engineer and construct what was originally named the Chicago Drainage Canal. But, when it was opened in 1900 it was called the Chicago Sanitary and Ship Canal as it is still called today. The I & M Canal was kept in service until 1933, primarily as a backup to the new canal.
USACE developed a unique solution to both the issue of waste entering Lake Michigan that would harm Chicago’s drinking water intake, and the issue of water supply across “the divide” to make the new canal viable. The solution was to reverse the flow of the Chicago River and have it drain not into Lake Michigan, but west through the new canal, through the height of land, into the Des Plaines, into the Illinois, and then into the Mississippi River and eventually the Gulf of Mexico – sewage and garbage and all.
The resulting canal connects the South Branch of the Chicago River which includes drainage from the North Branch, to the Des Plaines River at Lockport. The canal is 202 feet (62 m) wide by 24 feet (7.3 m) deep. In order to reverse the water flow, the Chicago Harbor Lock at the mouth of the Chicago River controls the flow of water into the river and subsequently into the canal and onwards to the Mississippi River. The only other lock on the canal is at its western end at Lockport to account for the 40-foot elevation difference between the canal and the Des Plaines River. The lock chambers are 600 feet (183 m) long by 80 feet (24 m) wide with a depth of 22 feet (6.7 m).
Given the success of this reversal of the natural flow of the river, the City of Chicago decided to apply the same solution to the flow of the Calumet River which carried sewage and garbage from South Chicago into Lake Michigan. Completed in the early 1920s, the Cal-Sag Channel, shortened from its full proper name, the Calumet-Saganashkee Channel, runs 16 miles (26 km) and joins the Calumet River to the Chicago Sanitary and Ship Canal. Instead of draining into Lake Michigan, the Calumet River now drains westward. There is one lock -- the O’Brien Lock -- with water control where the Little Calumet River joins the man-made channel. Commercial and pleasure boaters alike utilize this canal.
This successful reversal of the flow of a major river was one of the greatest feats of modern engineering at the time. Once the canal was completed, many of the workmen went on to help build the Panama Canal. The Chicago Harbor lock, which maintains the Chicago River roughly two feet lower than Lake Michigan, is currently the fourth busiest commercial lock and the second busiest recreational lock in the United States. It averages almost 12,000 lockages per year with just under 50,000 vessels, both recreational and commercial carrying a total of 700,000 passengers and 200,000 tons of cargo.
The slow-moving Des Plaines River originates south of Milwaukee and meanders a total of 133 miles (214 km) southward and almost parallel to the western shore of Lake Michigan. It continues southward through the western suburbs of Chicago and then turns southwest. After this turn, the Chicago Sanitary and Ship Canal runs virtually parallel to the river. The two join together at Lockport, about 30 miles (48 km) southwest of Chicago where the Des Plaines River is sufficiently wide and deep enough to handle commercial traffic. Lockport got its name and existence from being the headquarters and Lock Number One of the original Illinois & Michigan (I & M) Canal.
Roughly 20 miles (32 km) downstream from Lockport and through Joliet, Illinois, the Des Plaines River joins with the Kankakee River to become the Illinois River, one of the several major tributaries of the Mississippi River. From here, the Illinois River flows through Peoria and southwest for a distance of 273 miles (440 km), the last 20 miles (32 km) being almost parallel and close to the Mississippi River. The Illinois River empties into the Mississippi River near Grafton, IL, just a few miles north of St. Louis, Missouri.
Given the amount of boat traffic both recreational and commercial, the Illinois Waterway is both unique and necessary to both the bi-directional commerce of midwest United States and the recreational boat traffic enjoying world-renowned cruising. And of course it is an essential link in completing the navigation of the Great Loop.
There are some interesting asides to the Illinois Waterway. By 1920, the City of Chicago embarked on a major civic project to clean up its sewage system – to divert all the individual sewer pipes that fed into the rivers and canals and diver them into treatment facilities. They constructed multiple facilities and by 1972 added the Tunnel and Reservoir Plan (TARP), which at the time was one of the country’s largest public works projects.
You may have heard about Asian carp, also known as silver carp or flying carp. With the approval of the Environmental Protection Agency (EPA), the species was knowingly introduced into catfish raising farms in Arkansas in the 1970s to remove algae from the fish pens. Of course some escaped and multiplied vigorously while filter feeding on local sportfish species. The carp expanded northward into the Illinois Waterway.
Underwater electric fences were built in the Chicago Sanitary & Ship Canal to keep the carp from expanding into the Great Lakes -- the fear was their potential to destroy the sportfishing stock there as well. Today, there are no known established populations of Asian carp in the Great Lakes, but there has been talk of once again separating the two Illinois watersheds to prevent invasive species from entering. Because of these electric fences, swimming is not allowed in parts of the Sanitary & Ship Canal, but it as been allowed in the Chicago River since the early 2000s.
There is still another major controversy with the Illinois Waterway. Since redirecting the flow of the Chicago River from Lake Michigan to essentially the Mississippi River, populations downstream in the Great Lakes basin have formed opinions about how much water can, and should, be redirected from the Great Lakes. Most cities and towns bordering the Great Lakes basin utilize this great fresh water supply for their drinking and sanitary needs and then, following treatment, return the water to the basin.
But not Chicago. Between the removal of fresh drinking, sanitary, and commercial needs water from the lake, plus the input of lake water via the Chicago Harbor Lock to provide sufficient depth in the river and canal, the question has always been how much water can be removed from the Great Lakes basin without causing irreparable damage.
From the moment the Illinois Waterway opened, there have been discussions about how much water is enough. Regulatory bodies and opinions have changed several times. In the 1930s, the United States Army Corps of Engineers was given the authority to regulate the amount of water that could be drawn, but that didn’t work out. Since 1909, a Boundary Treaty between Canada and the United States has managed the international water issue through an International Joint Commission (IJC). Since Canada, as well as downstream states such as Michigan were questioning the amount of water being diverted by Chicago, the IJC was called in to adjudicate.
Following the IJC recommendation and formalized under regularly updated US Supreme Court decisions, Chicago is currently allowed to draw, still under the management of USACE, around two billion gallons (7.5 billion litres) of water per day, about half of which is for drinking, sanitary, and commercial use. It eventually gets flushed into the canal and downstream to the Mississippi. The other half includes water for navigation purposes in the river and canal.
The IJC has also determined that the volume of water that Chicago diverts is miniscule and negligible to the watershed of the Great Lakes basin compared to the influence of natural occurrences within the massive watershed. So, the next time a neighbouring boater blames low water somewhere on the Great Lakes to Chicago, you can smile to yourself as you know the real story.
On a cheerful note, with Chicago having one of the highest populations of Irish Americans, for the past 60+ years, the Chicago River has been dyed green, using vegetable dye, in honour of St. Patrick’s Day on March 17.
The Illinois Waterway has become so important to so many people, and as the link between some of the greatest and most abundant fresh water cruising in the world, boaters can only hope it maintains its health for decades to come.
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