Rain Drain

Days like this I would always run to the tap and get a mouthful of water and see if I could taste the extra chlorine. Usually I could. The extra chlorine in the tap water signified that Chicago had gotten so much rain that they had to open the locks and let the Chicago River – rife with untreated sewage – go into the lake.

This is a historical problem endemic to building a major city in a swamp, and one that Chicagoans have been trying to solve for 170 years. When they designed the Illinois & Michigan Canal in the 1830s, they planned to make it 8 feet deep in order to reverse the flow of the Chicago River, thus preventing sewage from befouling the drinking water brought in from the lake. They couldn’t afford such a deep canal, so the answer for years was to move the intake cribs – where the water comes from the lake – further out to escape the sewage. Chicago sewage system dumped directly into the river, and it was only added in the 1850s. In 1871 they managed a deep cut of the canal, but various developments ended the reversal of the Chicago River and the muddy little creek and Chicago’s stormwater and sewage trickled into the lake.

Pretty soon it was a million-person city and lots of those persons were hit with typhoid and cholera and other waterborne diseases so in 1889 they created the Metropolitan Sanitary District to dig a new canal to really reverse the Chicago River for good. That canal opened in 1900 and did the trick. Mostly. There were always five or six days a year when you got so much rain that the canal couldn’t cut it, and they opened the locks and let the sewage into the lake.

Then in the 1970s they started the Deep Tunnel, a multi-billion dollar reservoir – a 30-foot tunnel 300 feet underground, designed just so they could hold all the stormwater until it was treated, eliminating the need to open the locks and let sewage into the lake. Well, almost eliminating.

Deep Tunnel has several sections, some of which have been on-line for two decades, but still you get one or two days a year when the tunnel and the canal and everything is overwhelmed and the locks are opened and the River flows back naturally into the lake. Like yesterday.

I always feel a great sense of historical connectedness when I taste that extra chlorine.


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