Chicago Sanitary and Ship Canal

The Chicago Sanitary and Ship Canal, which runs roughly twenty-eight miles from the Chicago River to Lockport, Illinois, is one of the most audacious feats of civil engineering in American history: a canal built not to move goods, but to reverse the flow of an entire river system to save a city from its own sewage.

By the eighteen eighties, Chicago was dumping its waste directly into the Chicago River, which flowed into Lake Michigan, which supplied the city's drinking water. Typhoid and cholera epidemics were recurring catastrophes. In eighteen eighty-five, a rainstorm washed so much sewage into the lake that the city's water intake was contaminated for months. The death toll ran to thousands. Something had to be done.

The solution, championed by chief engineer Isham Randolph and approved by the Illinois legislature, was staggering: dig a canal deep enough and wide enough to reverse the Chicago River's current, sending it south and west away from the lake, down toward the Illinois and Des Plaines rivers and eventually to the Mississippi. The project broke ground in eighteen ninety-two and employed an average of eight thousand five hundred workers at peak. They excavated more earth than the entire Panama Canal. The canal opened on January second, nineteen hundred.

The reversal worked. Chicago's typhoid death rate fell dramatically in the following years. But the reversal pushed the problem downstream. St. Louis sued Illinois, arguing that Chicago was sending its sewage toward Missouri's drinking water. The Supreme Court sided with Illinois in nineteen oh six, establishing that the public health of the nation's second-largest city outweighed downstream objections. The canal also became a vital commercial shipping route between the Great Lakes and the Mississippi River system, linking Chicago's port to the Gulf of Mexico. Today it is also the front line in a different crisis: keeping invasive Asian carp from crossing between the Mississippi basin and the Great Lakes.