Call to Action: An Intervention on Water

Guest post by Reuben Keller.

You wouldn’t know it now, but Chicago was once an enormous swamp. If you’d begun at the lake and walked West, you would have crossed a series of dunes and swales, and then found yourself in miles of marsh and wetland. Only occasional ridges and high points would have supported any trees. Running through this was the small, seasonal, Chicago River. Not much to look at before Chicago was founded, Sieur de LaSalle commented in the 1680s that it was “ten to fifteen yards wide, and only a few inches deep”. At this time, the River that now sports tour boats, barges and yachts was “not even navigable by canoes, except after [the Spring] flood”.

If the river was so small, where was all of the region’s water going? Not a bad question, and the answer lies in the swamps. It used to rain about as much as it does now, but swamps act like giant sponges, soaking up and storing the rain. Not only that, but water sitting on the surface evaporated, and plants transpired huge volumes of water back to the atmosphere. About 70% of the rain the fell on the region went back into the atmosphere through one of these routes. The rest seeped into the Lake, into groundwater, or flowed into Lake Michigan through the Chicago River.

Chicago’s landscape changed as settlers built the city. They needed to drain the swamps to create safe building conditions. To do this, they installed drains, many of which emptied into the River. This gave dry land for building, and moved water off the land much more quickly, before it could return to the atmosphere. The network of drains grew along with the City, and now there is virtually no swamp left. Instead, rain is funneled quickly into drains, then piped to treatment plants that later discharge it into the Chicago River. That’s why the River is so much larger now; it now carries virtually all the rain that falls in the region.

In the midst of all this swamp draining and river building, the City found itself in the late 1800s with a huge disease problem. All of Chicago’s residential and industrial sewage, which wasn’t treated at the time, was piped into the Chicago River, and then flowed into the Lake. At the same time, Chicago was drawing its drinking water from the Lake. Not surprisingly, rates of disease were high, with Typhoid in particular killing many residents. Something needed to be done.

The Chicago region’s geography as a flat, swampy, area came to the rescue. The continental divide between the Great Lakes and the Mississippi watersheds – the ridge that determines whether a drop of rain flows East through the Great Lakes to the Atlantic or West through the Mississippi to the Gulf of Mexico – is just west of the city. It’s not much to look at as continental divides go, and Illinois decided to breach it. A canal was dug to connect the Chicago River to the Des Plaines River, which then flows into the Illinois and Mississippi Rivers. The final part of the trick was to reverse the flow of the Chicago River. This was accomplished with a series of locks that still operate, and the Chicago Sanitary and Ship Canal, as it’s known, was opened in 1900.

How did this help Typhoid? As you may have guessed, the solution to Chicago’s disease problems was to move its sewage away from its drinking water, through the Mississippi and out to the Gulf. Needless to say, cities like St. Louis, which draw their drinking water from the Mississippi, were outraged. But, a number of Supreme Court cases later, Chicago still pumps its wastewater to the Mississippi, and draws relatively safe water from the Lake for drinking.

Which brings us to invasive species. The canal was originally far too polluted by Chicago’s sewage – more polluted than local septic tanks, by some reports – to support any life. Over time, the Metropolitan Water Reclamation District has begun to treat the sewage, and by the 1970s the Canal, and the Chicago River, were returning to a better level of health. Overall, this was a good thing. The problem was that this has allowed aquatic species to move from the Great Lakes to the Mississippi, and vice versa. As people on both sides of the divide become more concerned about invasive species and the damage they cause, the Canal has become a big issue.

Asian carp are just the latest species to use the Canal to get from one watershed to the other. Zebra mussel, one of the world’s most notorious invaders, moved from the Great Lakes to the Mississippi through the Canal in the 1990s. It’s now found as far West as California, where it causes tens of millions of dollars in damage. Other species, including invasive plants and fish diseases, are poised on each side of the canal. This is not a problem that will go away anytime soon.

Unfortunately, there is no easy answer. Some have advocated re-engineering the system to close the Canal and make the two watersheds separate again. Many cities now treat their water to a high enough standard that it could be returned to the Lake, so this is a real possibility for Chicago. It would solve the invasive species problem, but would require expensive modifications to Chicago’s piping and water treatment systems. It may also harm the shipping and barge industries that use the Canal. Other options are to beef up defenses within the Canal. There are already electric barriers to discourage fish movement, and other types of non-physical barriers have been suggested. These would also be costly, and we don’t know how well they’d work – no-one has tried these experimental technologies before. There may be yet more options, and perhaps these will come to light as government agencies continue to investigate the problem.

Again, there is no easy solution, but there is a very definite and very large problem. Addressing it will be expensive and will probably take years. Failing to address it will mean more invasions on both sides of the divide, and huge environmental and economic costs from those invasions. Of all the options available, inaction certainly doesn’t look like a good one.

Note: Much of the material about the history of the Chicago River comes from Joel Greenberg’s excellent book A Natural History of the Chicago Region, published in 2002 by University of Chicago Press.

A version of this article appeared in the Chicago Tribune on September 1 and is available at ChicagoTribune.com