The Chicago River reversal construction began on September 3, 1892.
The Chicago River Reversal occured because the Chicago River was polluting Lake Michigan, our source of drinking water. Sewer systems were connecting the houses to Lake Michigan via the river. Eventually the lake became so incredibly full of sewage (pollution) that people drinking it became sick with cholera and typhoid fever. The death rate dropped from 80 deaths for every 100,000 people per year to less than 10 deaths per 100,000 people the year after the Sanitary and Ship Canal opened.
In 1889 the Metropolitan Sanitary District (MSD) created the Sanitary and Ship Canal, a new drainage system that allowed Chicago River to flow out of Lake Michigan instead of into it. It took eight years to dig the new drainage canal, which was 28 miles long and 24 feet deep. It allowed water (and sewage) to flow to the Des Plaines River, through the Illinois River, and then into the Mississippi River.
But before the gates of the canal opened, residents of Missouri went to court, arguing that the dirty water was going into their river and threatening the St. Louis water supply. Before the protest was filed, the lock gates in Lockport were opened and the reversal began.
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