River That Was Reversed Forever

Picture a Chicago mother in the 1880s, filling a jug at the kitchen tap. The water in that jug began its journey in the clear, cold depths of Lake Michigan. But before it reached her home, it passed uncomfortably close to the city’s filth, because Chicago had arranged its plumbing in the worst possible way. The sewers emptied into the Chicago River. The Chicago River emptied into Lake Michigan. And Lake Michigan was where the drinking water came from.

Every heavy rain pushed a fresh load of waste from streets, homes, stockyards and slaughterhouses out into the same lake the city drank from. It was a loop of slow self-poisoning, and everybody in charge knew it. What nobody had ever done, anywhere on Earth, was the thing Chicago eventually decided to try: turn the river around and make it flow the other way, forever.

This is that story, in three acts.

Act One: A city outgrowing its own water

Chicago grew at a speed that still sounds made up. Around a million people lived there by 1890, and about 1.6 million by 1900, in a city that had been a small trading post within living memory. All those people produced waste, and the flat, swampy land offered no convenient place to put it. The river was slow and shallow, the ground barely sloped, and gravity did most of the dirty work by itself, carrying sewage down the river and into the lake.

The city tried to protect itself. Water was drawn from intake structures called cribs, sitting out in the lake, connected by tunnels dug under the lake bed in 1866 and 1874. Pipes and pumps in the older Illinois and Michigan Canal dragged some waste westward. But these were half-measures. In normal weather the pumps coped. In a storm, the river rose, overwhelmed everything, and reverted to its natural course, pushing untreated sewage straight out toward the intakes.

Disease was the constant companion of this arrangement. Cholera had torn through young Chicago in earlier decades, killing 678 people in 1849 and 1,424 in 1854. By the late nineteenth century, typhoid fever was the steadier killer, taking an average of 65 lives per 100,000 residents every year, and far more in bad years. The worst came in 1891, when the typhoid death rate reached 174 per 100,000. Clean water was not a luxury item in Chicago. It was the difference between a growing city and a graveyard.

Then, on 2 August 1885, a tremendous storm dropped more than six inches of rain on the city. The swollen river flushed its refuse far out into the lake, and terrified citizens watched the brown plume drift toward the intake cribs. As it happened, strong northeast winds held the wastewater back, and the feared disaster never arrived. But the scare burned itself into the city’s memory.

The famous 90,000 deaths that never happened

Here we have to stop and correct a story you may well have read elsewhere, because it appears in bestselling books and old newspaper reports alike. The legend says that the 1885 storm caused an epidemic of typhoid and cholera that killed 90,000 Chicagoans, and that this catastrophe forced the city to act.

Historians who went back to the records found something very different. There were no cholera deaths in Chicago in 1885; the city had not seen a cholera outbreak since the 1860s. Typhoid deaths rose only slightly that year, and in no year of the 1880s did typhoid kill more than 1,000 people. A death toll of 90,000 would have wiped out about 12 percent of the entire city. It would have filled newspapers, church registers and burial grounds. Researcher Libby Hill, who wrote a history of the Chicago River, searched for those records and found none, and in 2005 the Chicago Tribune formally retracted its own earlier mentions of the epidemic.

So the storm of 1885 was a warning, not a massacre. The real killer was the everyday, unglamorous drip of typhoid, year after year. Chicago did not need a legend to justify what came next. The truth was reason enough.

Act Two: The impossible plan

The solution, approved by voters with a staggering 99 percent support, was to create a new authority, the Sanitary District of Chicago, established in 1889. Its assignment was blunt: reverse the river.

The geography, awkward in every other way, offered one gift. West of Chicago lay a low continental divide, in places only a few metres above the lake. Beyond it, the land drained toward the Des Plaines River, then the Illinois River, then the mighty Mississippi, and finally the Gulf of Mexico. If engineers cut a canal through that divide and dug its bed deeper than the level of Lake Michigan, gravity would do the rest. Lake water would flow into the river, the river would turn around, and the city’s sewage, diluted in all that fresh lake water, would travel away from the drinking supply. The district called the philosophy “disposal by dilution.”

The canal they designed, the Chicago Sanitary and Ship Canal, ran about 28 miles from the river at Bridgeport to the Des Plaines River near Joliet. It was roughly 200 feet wide and 20 feet deep, much of it hacked through solid bedrock, and it remains one of the largest earth-moving efforts ever attempted. Work began with a celebration dubbed Shovel Day on 3 September 1892, and thousands of laborers spent the rest of the decade digging. The chief engineer, Isham Randolph, later carried the experience gained on this “Big Ditch” to the building of the Panama Canal.

Not everybody downstream was cheering. The water Chicago wanted to send away would pass, eventually, the city of St. Louis, which drew its own drinking water from the Mississippi. St. Louis newspapers raged against the plan for years. As the canal neared completion, word spread that Missouri was preparing to ask the United States Supreme Court for an injunction that would stop the gates from ever opening.

Chicago’s trustees responded the way Chicago often has: they moved first and argued later.

The quiet morning the river turned around

In the cold early hours of 2 January 1900, two weeks before the official opening ceremony and without all the proper permits in hand, the Sanitary District Board quietly ordered a needle dam knocked down. Water from the new canal met the Chicago River, and the river began, slowly and then certainly, to flow backwards. Two weeks later, with permits sorted out, the great controlling works at Lockport were opened, and the reversal became permanent fact. For the first time in roughly 12,000 years, water from the Great Lakes was flowing freely into the Mississippi basin.

There was no dramatic wall of water, no Hollywood moment. People simply noticed the current going the wrong way, and the river running clearer as lake water pushed through it. A project built to be argued about in court had made itself very hard to argue with: it is easy to sue a construction site, and far harder to sue a river that is already flowing.

Act Three: The courtroom sequel

Missouri filed its case anyway, and Missouri v. Illinois became one of the landmark environmental cases in American legal history. St. Louis argued that Chicago’s sewage, sent down the river system, was sickening its people.

In 1906, the Supreme Court ruled for Illinois. Justice Oliver Wendell Holmes delivered the decision. His reasoning was practical: Missouri had failed to prove that Chicago’s waste, diluted over hundreds of miles of flowing water, was the cause of illness in St. Louis. It did not help Missouri’s case that St. Louis and the towns between the two cities were pouring their own raw sewage into the same rivers. The reversal stood, and Chicago’s backward river became a permanent feature of the continent. In 1955, the American Society of Civil Engineers named the canal one of the Seven Wonders of American Engineering.

The health results at home were what the engineers had promised. With sewage no longer drifting toward the intakes, Chicago’s waterborne disease rates fell sharply in the years that followed, and the city kept growing into the metropolis it is today.

The river today: green days and electric fences

Walk along the Chicago River now and you are looking at a working monument. The water still flows away from Lake Michigan, held in that unnatural direction by locks and control structures, and since around 1950 the water sent down the canal has been fully treated rather than merely diluted. The river that once hosted only a handful of fish species by the 1960s now supports a livelier ecosystem, riverwalks, tour boats and kayaks.

Once a year, it also turns a shamrock green. Since 1962, the local plumbers’ union has dyed the river for Saint Patrick’s Day, a tradition born when dye used to trace sewage leaks stained a plumber’s white overalls green. Today’s version uses a vegetable-based orange powder that turns green in the water and fades within hours, and crowds line the bridges to watch.

The reversal has also left one modern headache. By joining two great water systems that nature kept apart, the canal opened a highway for invasive species. Asian carp, which have overwhelmed stretches of the Illinois River, could use the canal to reach Lake Michigan and the whole Great Lakes system. To guard the door, the United States Army Corps of Engineers installed a series of electric barriers in the canal near Romeoville between 2002 and 2011. The barriers pulse electricity through the water to turn fish back, and monitoring suggests they stop all but the smallest fish from passing upstream.

To me, that is the perfect ending to the story, because it refuses to be simple. The canal is one of the greatest public health rescues in history, and it is also a permanent ecological problem that engineers must keep guarding, every single day, with electric fences. Chicago solved its crisis so completely that we now maintain the solution like a living thing. The river runs backwards, the city drinks safely, and the bill, in a sense, is still being paid — which is true of nearly every bold thing human beings have ever built.

Common questions

Does the Chicago River really still flow backwards? Yes. More than 125 years after January 1900, the river’s main flow still runs away from Lake Michigan toward the Mississippi system, maintained by locks and control works. In exceptional flood emergencies the flow can briefly be allowed toward the lake, but backwards is its normal, everyday direction.

Why did Chicago not just build water treatment plants instead? In the 1890s, treating the sewage of a million-plus people to a safe standard was beyond the technology and budgets of the time. Dilution in a huge flow of lake water was the practical tool available. Treatment works were added later, and by about 1950 all the water in the canal was fully treated.

Did 90,000 people really die in Chicago in 1885? No. That widely repeated figure is a legend. Mortality records show no cholera deaths in Chicago that year and only a slight rise in typhoid, which never killed more than 1,000 people in any year of the 1880s. The 1885 storm was a frightening near-miss, not a mass-fatality epidemic.

Why did St. Louis lose its Supreme Court case? In Missouri v. Illinois (1906), the Court found that Missouri had not proved Chicago’s diluted sewage was making St. Louis sick, especially since St. Louis and other towns were adding their own raw sewage to the same river system.

What keeps Asian carp out of Lake Michigan today? A set of electric barriers built by the US Army Corps of Engineers in the canal near Romeoville. They create an electric field in the water that drives fish back downstream, guarding the man-made connection between the Mississippi basin and the Great Lakes.