Reversal of the Chicago River

The Sanitary and Ship Canal

Cableway and moveable towers. Image source: The Traveling Cableway and Some Other Devices Employed by Contractors on the Chicago Main Drainage Canal. New York: Lidgerwood Manufacturing Co., 1895, p. 9.

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From the 1850s, untreated sewage flowed into the Chicago River and was carried into Lake Michigan where it overwhelmed the intake cribs for pure water, particularly during spring floods. In August 1885, more than six inches of rain overwhelmed the pumping stations and sewer pipes, fouling the city's water supply and killing almost 12 percent of the population with cholera and other diseases.

A solution proposed in 1889 recommended that the Chicago River be reversed. Instead of flowing into Lake Michigan it would, in effect, flow into the Gulf of Mexico. The project involved the construction of a 28-mile channel through a glacial moraine and bedrock ridge. The Sanitary and Ship Canal would connect Lake Michigan at Chicago with the Des Plaines River at Lockport. It would also be connected to the Chicago River and would be deep enough to permanently reverse the flow of the river. This trade publication, issued at the height of construction, shows the cableway with moveable towers that was used to hoist and remove debris from the channel.

Digging Techniques

Osgood Steam Shovel at work. Image source: Hill, Charles Shattuck. The Chicago Main Drainage Channel. A Description of the Machinery Used and Methods of Work Adopted in Excavating the 28-Mile Drainage Canal from Chicago to Lockport, Ill. New York: The Engineering News Publishing Co., 1896, p. 42.

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The monumental feat of reversing the flow of the Chicago River, so that it now flows from Lake Michigan into the Mississippi, involved not only canal building, but also river dredging and bridge and road building. The final 15 miles were dug through rock with the help of dynamite and steam shovels mounted on rails in the trench to remove the debris. This digging technique was adopted a few years later in the Panama Canal dig.

Extensive dredging of the Chicago River was also required in order to reverse its flow. When the canal's gates were opened at Lockport in January 1900, the river changed its direction as planned and sewage stopped flowing into Lake Michigan. Dilution and natural biological processes were adequate to render the sewage harmless to downstream communities until the 1920s, when treatment plants were constructed. The Sanitary and Ship Canal continues to carry drainage and barge traffic, operating as originally conceived.

Map of the Chicago River and Drainage Canal. Image source: Hill, Charles Shattuck. The Chicago Main Drainage Channel. A Description of the Machinery Used and Methods of Work Adopted in Excavating the 28-Mile Drainage Canal from Chicago to Lockport, Ill. New York: The Engineering News Publishing Co., 1896, insert 1, fig. 2.

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