The Chicago River Reversal, Engineering Against Nature

Stand at the Michigan Avenue bridge and watch the Chicago River moving west, away from the lake. That direction is not natural. For most of the city's history, the river flowed east, into Lake Michigan, carrying with it everything the city put into it: industrial waste, slaughterhouse runoff, and human sewage. The lake was also where Chicago drew its drinking water. For decades the city essentially drank from its own drain, and the results were predictable. Cholera epidemics. Typhoid outbreaks. Thousands dead in the worst years.

In January nineteen hundred, Chicago completed one of the most ambitious civil engineering projects in North American history: the Sanitary and Ship Canal, twenty-eight miles long and thirty-two feet deep, dug southwest from the Chicago River to connect it to the Illinois and Michigan Canal and ultimately to the Mississippi River drainage. The project moved more earth than the Panama Canal required. It cost twenty years of planning and construction. When the canal's sluice gates opened on January second, nineteen hundred, the Chicago River began flowing in the opposite direction for the first time in geological memory.

Downstream communities were not pleased. St. Louis sued, arguing that Chicago was now pumping its sewage toward Missouri. Missouri, joined by several other states, pressed the suit. The case went to the United States Supreme Court, which ultimately ruled in Chicago's favor. The reversal held. Chicago's typhoid death rate dropped by half within a decade, one of the most dramatic public health improvements in American urban history.

The engineering required to pull this off was, by any measure, extraordinary. The men who dug the canal worked by hand and with steam shovels in conditions that killed dozens. The project's chief engineer, Isham Randolph, later served as consulting engineer on the Panama Canal, where he drew on what he had learned in Chicago. The city that made itself famous for burning down also made itself famous for solving problems at a scale that no one had attempted before.