Chicago, the City of Water Engineering

Chicago is known for many things. It’s windy. It’s got many great museums. Four incredibly storied sports franchises (and then the White Sox). A river that is dyed green each March 17. It was a major center of organized crime during Prohibition. And though I’m about to commit serious blasphemy as a New Yorker, I believe deep-dish pizza is the superior pie.

But Chicago is earning a reputation as the city of water engineering. To earn such a distinction, it requires consistent reinvestment in critical water infrastructure, something Chicago first did in the 1850s.

Originally, central Chicago was the same height above sea level as nearby Lake Michigan, which meant muddy streets and pools of standing water were a fact of daily life. As the city population grew, the lack of drainage contributed to epidemics of typhoid fever, dysentery and cholera. A proper sewage system was required, but technology at the time required that the system work by gravity. In 1856, engineer Ellis S. Chesbrough proposed raising the majority of Chicago by 4 to 14 feet so sewers could be installed underneath.

Masonry buildings were raised one at a time by jackscrews before the sewer was installed and the street grade elevated. Wooden and outdated buildings were placed on rollers and moved to the outskirts of town, while poor masonry neighborhoods and building owners were basically just skipped over. It’s why many small, old brick buildings in Chicago still have first floors below street level. The most impressive feat was the raising of half a city block that was 320 feet long, weighed 35,000 tons, and had buildings five stories high. Six thousand jackscrews and 600 workers raised the block which contained a bookstore, pharmacy, shoe store and other businesses. Citizens were allowed to walk underneath the block after it was raised and patronized stores while they were elevated or being rolled to a new location.

After 20 years, Chicago had a new height above sea level and city river of sewage that drained into Lake Michigan. Somehow nobody realized that dispatching wastewater into the city’s drinking water was a bad idea, so Chesbrough’s expertise was needed again. Three canals were built south of Chicago from 1892 to 1922, with the Sanitary and Ship Canal connecting the northeast-flowing Chicago River into the southwest-flowing De Plaines River, which reversed the flow of the Chicago River, diluted and aerated it, and eventually dumped Chicago’s sewage into the Mississippi River. In 1931, Chicago built the Stickney Wastewater Treatment Plant along the S&S Canal, and it remains the largest water treatment plant in the world.

Since Chicago is sloped towards the lake in the northeast, but drainage runs southwest, it is prone to flooding from storms, which also causes sewage to overflow into Lake Michigan. To remedy this issue, the city initiated the Tunnel and Reservoir Plan (TARP) in 1972. TARP called for the creation of underground holding tunnels for excess storm and sewage water. Phase 1 of TARP was completed in 2006 after 31 years of tunnel excavation. The tunnels are 109 miles long, 9-33 ft. in diameter, and hold up to 2.3 billion gallons of sewage. Phase 2 of TARP won’t be completed until 2029, and will provide 17.5 billion gallons of reservoir space for excess wastewater.

In 2012, Chicago began a 10 year plan to replace 900 miles of century-old drinking water pipes. Many cities around the United States face a similar scenario: desperately needing to replace outdated water mains, but little or no budget to do so. In 2008 Chicago began raising water rates, which has ultimately provided the city with an extra $225 million a year to invest in water infrastructure.

In 2016, the city launched Current, a public-private initiative that will research water treatment technologies and is expected to provide $250 million in local economic value due to the collaboration of municipal industrial, utility, and university engineers. Current’s goals are to improve the efficiency and resiliency of water systems, develop new water technologies, and increase local investment in the water industry, which employs nearly 100,000 people from Chicago and nearby areas.

Average individuals will continue to see the same Chicago at face value. Yet engineers and we here at CR4 can find something else to appreciate about Chi-Town.