From the mid to the late-19th century, Chicago was in the midst of a period of rapid growth, and as the city grew it placed enormous strain on the region’s natural resources. One of the biggest challenges the city faced was waste management. Like most growing cities of the period, residents viewed rivers as open-air sewers and dumped raw, untreated sewage and other pollutants directly into the river. Human waste and rotting carcasses of dead animals floated downstream into Lake Michigan, which was also Chicago’s primary source of drinking water.
Sanitary District trustees and others pose for a photo after breaking the last dam holding the Chicago River back from the Sanitary and Ship Canal on the morning of January 2, 1900. Courtesy of Metropolitan Water Reclamation District
To prevent the pollutants carried by the Chicago River and deposited on Lake Michigan from contaminating the city’s water supply, engineer Ellis Sylvester Chesbrough designed an underground intake tunnel, sixty feet under the lake. The mouth of the tunnel opened nearly two mile off-shore into the lake, allowing drinking water to be drawn from farther out, past the contaminating sewage.
But when a tremendous storm in 1885 carried refuse from the river far out into the lake, there were fears that sewage could reach the city's water supply intake and cause devastating water-borne diseases like cholera, typhoid, and diarrhea. This spurred the city into action, leading to the creation of the Sanitary District of Chicago (now the Metropolitan Water Reclamation District) to tackle the problem of Chicago’s waste disposal and protecting its water supply.
It was once again Chesbrough who came to the city’s rescue. Chesbrough proposed an audacious plan—reverse the flow of the river away from Lake Michigan. Chesbrough’s outrageous plan worked like this: just west of Chicago River lies a barely perceptible ridge called the Chicago Portage, that separates the drainage basin of the Great Lakes from that of the Mississippi River. Rainfall on the west of this divide flows naturally towards the Des Plaines River, which moves southward to converges with the Kankakee River to form the Illinois River, a tributary of the Mississippi. Any rainfall on the east of the divide flows into the Great Lakes. Chesbrough thought that if a canal could be dug through this divide and made it deeper than the water level of the Chicago river and the lake, gravity would cause the Chicago River’s stinky water to flow backward away from Lake Michigan.
Image credit: Milwaukee Journal Sentinel
To put plan into action, Chesbrough instructed that the existing Illinois and Michigan Canal be dredged and deepened to expand its ability to handle the city's sewage, but continued population growth quickly outstripped the canal's waste management capacity. Chesbrough realized that a bigger canal was required, but before the first shovel could hit the dirt, came the civil war followed by the Great Fire of Chicago in 1871. Work on the canal could not begin until 1892, six years after Chesbrough’s death.
Eight years later, the 28-mile long canal was complete, cutting through the Chicago Portage to join Chicago River to the Des Plaines River. Historically the canal was known as the Chicago Drainage Canal but now its called the Chicago Sanitary and Ship Canal, for it also functions as a navigation route for ships between the Great Lakes Waterway and the Mississippi River system. The canal was designed to get deeper as it moved west, allowing water to flow from the Chicago River into the Des Plaines. In the subsequent years, two more canals were built to increase the flow of the Chicago River—the North Shore Channel was opened in 1910, and the Calumet-Saganashkee Channel in 1922.
Chicago Sanitary and Ship Canal being built. Photo: Wikimedia Commons
Before the reversal, the North and South Branches of the Chicago River converged at Wolf Point to form the main stem, which flowed eastward and into Lake Michigan. Today, the main stem of the Chicago River flows west from Lake Michigan to Wolf Point, where it converges with the North Branch to form the South Branch, which flows southwest and empties into the Chicago Sanitary and Ship Canal.
Construction of the Ship and Sanitary Canal was the largest earth-moving operation that had been undertaken in North America up to that time. In 1999, the Chicago Wastewater System was named a “Civil Engineering Monument of the Millennium” by the American Society of Civil Engineers (ASCE).
The eight-year project was originally hailed as one of the greatest engineering marvels of the time, but reversing a river did have environmental costs. The most immediately affected were those communities that resided downstream. The influx of water from Lake Michigan nearly doubled the size of the Illinois River, causing spillage and erosion of the banks, inundation of surrounding farmlands and wildlife habitat up and down the valley. By 1905, nearly 300 landowners in the Illinois Valley filed suit against the Sanitary District of Chicago.
The reversal of the Chicago River also increased the pollution in the Mississippi river, which is the source of drinking water for the city of St. Louis. In 1900, Missouri filed a suit against the Sanitary District, but the case was dismissed when Missouri was unable to prove the pollution in the Mississippi came from Chicago, especially when St. Louis itself was dumping their wastes into the Mississippi River.
Sanitary District attorney Walter E. Beebe, who worked as a claims agent in the Illinois Valley, inspects erosion and flooding along the Illinois River in 1910 on the property of James Gentleman. Photo credit: CityFiles Press
Sanitary District attorney Walter E. Beebe, who worked as a claims agent in the Illinois Valley, inspects erosion and flooding along the Illinois River in 1910 on the property of James Gentleman. Photo credit: CityFiles Press
The Chicago River reversal also connected two of the world's largest freshwater ecosystems—the Great Lakes and the Mississippi River Basin. In doing so, they created a new pathway for invasive species. Among them is the Asian carp, that migrated through the Mississippi River system and now threatens to ruin the biodiversity of the Great Lakes. Preventing the influx of invasive water species now costs the Great Lakes Region billions of dollars every year.
Chicago and other cities began treating their sewage from around 1920, but progress was slow and the technology was primitive. It wasn’t until the passage of the Clean Water Act in 1972 that rivers began to recover. Still, throughout the 1980s, the Chicago river was quite dirty and often filled with garbage. The river underwent extensive cleaning during the 1990s as part of an effort at beautification by Chicago Mayor Richard M. Daley. Today, the number of fish species found in the Chicago River has increased nearly ten-fold, from less than 10 to more than 70.
References:
# Gregory D Smithers, Reversing a River: How Chicago Flushed its Human Waste Downstream, We’re History
# Floods, Carp, And Crap: The Environmental Impacts Of The Chicago River Reversal, NPR
# The Story Behind The Chicago River Reversal, Chicago Online
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