The Daily Parker

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Chicago's hidden depths

Slate explains how Chicago's Deep Tunnel project has relieved the city of the worst effects of rainstorms—but just isn't adequate for the new, wetter climate:

The history of Chicago can be told as a series of escapes from wastewater, each more ingenious than the last. Before the Civil War, entire city blocks were lifted on hydraulic jacks to allow for better drainage, and the first tunnel to bring in potable water from the middle of Lake Michigan was completed in 1867. In 1900, engineers reversed the flow of the Chicago River to protect the city’s drinking water, shifting its fetid contents from the Great Lakes to the Mississippi, enraging the city of St. Louis (which sued, and lost) and, years later, making Chicago the single-largest contributor to the “dead zone” in the Gulf of Mexico. In 1955, the American Society of Civil Engineers declared the river reversal one of the seven engineering wonders of the United States, alongside such better-known undertakings as the Hoover Dam, the Empire State Building, and the Panama Canal.

“The [Metropolitan Water Reclamation District] designed a system of sewers, tunnels, and reservoirs for a city that doesn’t exist anymore,” says Karen Hobbs, a former deputy environmental commissioner in Chicago who oversaw the creation of the city’s climate plan and now works as a policy analyst at the National Resources Defense Council. Metropolitan Chicago is no longer the place it was in 1960. The weather isn’t what it was then either. It’s a cautionary tale for a time when climate change has the nation’s planners, scientists, and engineers contemplating enormous endeavors like storm surge barriers or more radical, long-term geoengineering schemes. It’s also a reminder that any project that spans six decades from commencement to completion will be finished in a different world than the one in which it was conceived.

“It’s a marvel,” Hobbs adds. “But we have this tendency in this country to think we can build our way out of stuff. And we can’t always build our way out.”

Belatedly, the city has started using porous pavement in alleys and encouraging other ways of keeping water out of the sewers.

Comments (1) -

  • David Harper

    1/5/2019 9:29:01 AM +00:00 |

    Thanks for sharing that fascinating article.  A similar project is currently underway beneath the Thames in London, and for the same reasons: when there is heavy rainfall, the existing drainage system (built by Joseph Bazalgette in the 19th century) cannot cope, and a mix of sewage and rainfall runoff enters the Thames via numerous overflow drains.  The Thames is a reasonably clean river these days, so it's not like the Great Stink that led to the building of Bazalgette's pioneering sewer system, but raw sewage is a health risk to river users such as rowers.

    The solution is a new deep-level sewer that follows the route of the Thames, from 30 to 70 metres below ground level.  It's a major civil engineering project.  The BBC showed a three-part documentary about it in late 2018, which was fascinating.  It's as big a project as Crossrail.

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