The related Calumet-Saganashkee Channel does the same for the Calumet River a short distance to the south, joining the Chicago canal about halfway along its route to the Des Plaines.

The city's drinking water supply was (and remains) located offshore, and there were fears that the sewage could reach the intake and cause serious disease outbreaks.

[4] The I&M canal was also badly polluted as a result of unrestricted dumping from city sewers and industries, such as the Union Stock Yards.

After four years of turmoil during construction, Isham Randolph was appointed Chief Engineer for the newly formed Sanitary District of Chicago and resolved many issues circulating around the project.

Reports describe 400 quarrymen marching along the length of the canal project on June 2, between Lemont and Romeo, conducting a "reign of terror" at worksites, "armed with clubs and revolvers", "almost crazed with liquor".

[6] On the 9th strikers clashed with replacement workers and local law enforcement, and Governor Altgeld called out the First and Second Regiments of the Illinois National Guard.

[7] Dozens were wounded and at least five killed: strikers Gregor Kilka, Jacob (or Ignatz) Ast,[8] Thomas Moorski, Mike Berger,[7] and 17-year-old bystander John Kluga.

[15] The Chicago Sanitary and Ship Canal is designed to work by taking water from Lake Michigan and discharging it into the Mississippi River watershed.

At the time of construction, a specific amount of water diversion was authorized by the United States Army Corps of Engineers (USACE) and approved by the Secretary of War, under provisions of various Rivers and Harbors Acts; over the years however, this limit was not honored or well regulated.

While the increased flow more rapidly flushed the untreated sewage, it also was seen as a hazard to navigation, a concern to USACE in relation to the level of the Great Lakes and the St. Lawrence River, from which the water was diverted.

[16] The litigation was eventually decided by the Supreme Court in Sanitary District of Chicago v. United States in 1925,[17][18] and again in Wisconsin v. Illinois in 1929.

However, the MWRD’s Tunnel and Reservoir Plan (TARP) has worked to decrease the combined sewage overflow (CSOs) and nearly eliminated them in the Calumet Area River System.

TARP captures and stores combined stormwater and sewage that would otherwise overflow from sewers into waterways in rainy weather.

Carp were introduced to the U.S. with the blessing of the Environmental Protection Agency (EPA) in the 1970s to help remove algae from catfish farms in Arkansas.

On December 2, 2009, the Chicago Sanitary and Ship Canal closed, as the EPA and the Illinois Department of Natural Resources (IDNR) began applying a fish poison, rotenone, in an effort to kill Asian carp north of Lockport.

Siding with the State of Illinois, both the Illinois Chamber of Commerce and the American Waterways Operators have filed affidavits, arguing that closing the Chicago Sanitary and Ship Canal would upset the movement of millions of tons of vital shipments of iron ore, coal, grain and other cargo, totaling more than $1.5 billion a year, and contribute to the loss of hundreds, perhaps thousands of jobs.