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Wastewater Management in Chicago, Illinois

Overview of Great Lakes Wastewater Management
The Great Lakes Watershed
History of U.S. Wastewater Management
Risks and Problems
Milwaukee, WI
Chicago, IL
Detroit, MI
Citizen Groups
Rehabilitation and Action Plan

            Chicago, the largest urban area on the lakes,  lies on the southwestern edge of Lake Michigan, the second largest of the great lakes. The most important river system is the Chicago River, but the Calumet River runs through the city as well. The Des Plaines River to the northwest also plays a major role in Chicago’s wastewater management. The Chicago Sanitary and Ship Canal carries Chicago’s treated sewage to the Des Plaines River, where it goes on to the Illinois River, then the Mississippi River. Chicago sits on the continental divide between the Mississippi River and Great Lakes watersheds. Because of this, the Chicago Sanitary and Ship Canal was constructed to redirect the flow of water away from Lake Michigan and towards the Mississippi River. Chicago’s main source of municipal water is Lake Michigan, so there were a series of cholera and typhoid outbreaks due to unsanitary water from the 1850’s until 1900 when the canal was completed.

            Chicago’s sewer system was one of the first comprehensive combined sewer systems to be constructed in the United States along with Brooklyn in the late 1850’s (Burian et al, 43). The construction of this sewer system was a phenomenal feat because of the topography of Chicago: “Chicago’s topography, being unusually flat, was unfavorable to sewer construction…In reality, the task on constructing underground sewers required raising the city” (Cain, 360). Thus, in the late 1850’s, the city of Chicago was literally “raised” a few feet to accommodate the new sewer system.

            Sewage treatment plants were constructed in Chicago in the early 1900’s, but prior to this the combined sewage had flowed directly into the surrounding waterways (IDNR). The diversion of the Chicago River via the construction of the Sanitary and Ship Canal stopped the dumping of sewage into Lake Michigan, but the rivers were still receiving heavy loads of pollutants (IDNR). By the 1950’s, however, the Sanitary District’s treatment plants “could capture and treat about a billion gallons per day” (IDNR).

Dealing with Sewer Overflows

            Chicago’s sewer treatment system was originally designed to treat about 2 billion gallons of wastewater per day, but it “may be inundated with more than 5 billion gallons of rainwater runoff (about 1" of rain) during a single rainstorm” (TARP). This resulted in many sewer overflows until a solution was found in the 1970’s. Engineers came up with a plan that “selected as best and most cost-effective was the Tunnel and Reservoir Plan — or TARP. Under this plan, 109 miles of huge underground tunnels would be burrowed under the city to intercept combined sewer overflow and convey it to large storage reservoirs. After the storm had subsided, the overflow could then be conveyed to treatment plants for cleaning before going to a waterway” (TARP). The first stages of this grand plan were put into service in 1985, and it was immediately heralded as a huge success (TARP). Now over 20 years later, there have been significant improvements in the water quality of the Chicago River, the Calumet River, and other waterways in the area (TARP). Furthermore, the project “was named by the USEPA as one of the nation's top Clean Water Act success stories, and is serving as a model urban water management tool worldwide” (TARP). 

            TARP was certainly an effective method to mitigate dumping of raw sewage into Chicago’s waterways. However, despite the gleaning reports from its advocates, greater Chicago still dumps huge amounts of wastewater in overflows every year. For instance, in 2004 alone, the greater Chicago area dumped over 1 billion gallons of untreated combined sewage in 15 separate overflow events (MWRDGC PS Activity). The year 2005 was slightly better, with just over 700 million gallons dumped in just 4 overflow events (MWRDGC PS Activity). While Chicago’s discharged waste no longer flows directly into Lake Michigan, it does flow down the (redirected) Chicago River, to the Illinois, Des Plaines, and Mississippi Rivers, causing equal if not greater devastation.

            Today Chicago’s wastewater treatment is somewhat decentralized, using a system of seven different wastewater treatment plants (MWRDGC Facilities). These seven plants have the capacity to treat billions of gallons of wastewater every day, and serve an area of hundreds of square kilometers and millions of people (MWRDGC Facilities). However, in times of heavy rain or snowmelt, Chicago’s vast sewerage system can still be overwhelmed, as we have seen evidence of.

            Just because Chicago’s wastewater does not enter Lake Michigan does not mean that the lake water and beaches near and around Chicago are clean or safe. Chicago’s sanitation problems are compounded by the natural flow of currents within Lake Michigan. The wastewater dumped by the city of Milwaukee (which DOES flow into Lake Michigan) occasionally finds its way down south to Chicago. A number of lawsuits in the past few decades have held Milwaukee responsible for polluting waters which eventually reach Chicago. A lawsuit from 1977 first forced Milwaukee to begin investing in a new system to mitigate sewer overflows, when “a federal judge ruled that Milwaukee was potentially harming Illinois residents by routinely dumping untreated sewage into Lake Michigan (Rohde). However, more recent lawsuits, particularly one in 2004, have dismissed claims by the city of Chicago that Milwaukee’s overflow events are causing beach closings in the Chicago area (Alliance).

Citizen Environmental Action:

            There are many citizen based groups working for the protection of Chicago’s lakes and waterways. These include: the Friends of the Chicago River, the Nature Conservancy – Great Lakes Office, the Great Lakes Water Quality Network, and the Alliance for the Great Lakes.

            Recently, the Alliance for the Great Lakes led an effort to push the Bush administration to drop its proposed federal sewage policy. This policy “would permit sewage treatment plants to divert sewage around secondary treatment operations anytime it rains, allowing largely untreated sewage to ‘blend’ with fully treated wastewater before discharge to waterways” (Alliance). Treatment plants are already allowed to divert sewage, but only under extreme circumstances. According to the citizen groups involved, the proposed policy “the proposed policy would provide a disincentive for treatment plants to upgrade their facilities and make necessary repairs” (Alliance). The Alliance for the Great Lakes organizes citizen groups to form a strong front in fights such as this one. The citizen groups were eventually victorious, when the proposed plan was thrown out by congress “in the face of 98,000 public comments” (FMR 1).

            The Alliance also provides citizens with information regarding water quality and news of overflow activity and environmental risks. Furthermore, it provides citizens with information and resources required to make a difference. It gives addresses and dates of public hearings, phone numbers, addresses to send letters, and email addresses to which comments can be made. It provides opportunities for volunteering and citizen action such as an “Adopt-a-beach” program. Finally, it partners up with local Chicago businesses (like Shaw’s Crab House) as well as international businesses (like Patagonia) to build support both in and out of the community.   

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Downtown Chicago, Illinois from the air.  (   

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Chicago, Satellite
                        Satellite image of Chicago

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Downtown Chicago from Lake Michigan


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