The Chicago River was permanently reversed in 1900. The reversal prevented the thousands yearly deaths due to waterborne diseases such as typhoid fever and cholera.
Typhoid fever is a disease that is spread when food or water becomes contaminated with human feces (poop). It causes abdominal pain, headaches, rashes, and a high fever. Typhoid fever is fatal when left untreated. Cholera is caused by the bacterium Vibrio Cholera. Cholera can cause victims to convulse in pain, violently vomit and have uncontrollable diarrhea. If not treated victims will turn blue and quickly die.
As Chicago developed into a big city, the Chicago River was used to dump sewage, factory waste, and other harmful wastes. This badly polluted the river. The Chicago River is connected to Lake Michigan which is Chicago’s main source of water. During big rainstorms, the river would overflow into the lake. The drinking water would soon become polluted and spread diseases. In the span of a couple of years, waterborne diseases had killed more than 5% of Chicago’s population.
In 1822 Congress authorized construction of the Illinois and Michigan Canal. Construction began in 1836 but stopped for four years in 1841. It was completed in 1848 and the I & M canal was open to traffic. They soon realized that the canal was not stopping the sanitation problem. For several years there was many trial and error attempts to fully reverse the river. In 1900 they deepened the canal and the river was permanently reversed.