TODAY IS THE 25TH ANNIVERSARY OF THE CHICAGO FLOOD

I wrote this post for the Chicago Detours Architecture and History Blog and wanted to share it on here as well. Enjoy!

The Chicago flood of April 13, 1992 was a deeply strange and unexpected event. Hundreds of thousands of workers showed up in the Loop and River North just like usual and were promptly sent home. Even venerable institutions like the Board of Trade were shuttered, costing the city billions in lost productivity. The city center shut down because 250 million gallons of water from the Chicago River were coursing through basements across downtown. It was the great Chicago flood and it was a classic Chicago fiasco.

How’d the Chicago Flood Happen?

The wooden pilings surrounding the Kinzie Street Bridge caused the Chicago flood. Image via Wikimedia

The Chicago flood began when a construction crew drove a new wooden piling into the Chicago River near the Kinzie Street Bridge. In doing so, they inadvertently drove a hole into the roof of a long-neglected tunnel. It was a part of the larger Chicago Tunnel Company system, much of which was dug in the early 20th Century.

This network of tunnels was constructed in the clay 40 feet below the city streets. Originally planned to carry telephone lines, they eventually carried everything from retail packages to coal ash. The system was incredibly large, covering over 60 miles in downtown Chicago at its peak. Competition from the trucking industry eventually drove the Chicago Tunnel Company out of business and their warren of tunnels was mostly forgotten. Until April 1992, that is.

The Slow-Motion Disaster of the Chicago Flood

The Chicago flood didn’t start in a flash. The pilings that caused the leak were driven over six months prior in September 1991. A cable company worker noticed water entering the tunnels in January 1992. A city electrical technician examined the leak and even took video footage. He alerted his superiors, but City Hall rejected a $10,000 repair bid as too costly. They planned to have another contractor do an inspection on April 14. Welp.

The roof of the tunnel gave way in the early morning of April 13 and the Chicago flood was on.

The story was broken by Larry Langford, an overnight radio reported for WMAQ. He heard someone on a police scanner exclaim that there were fish in the water flooding the Merchandise Mart. Thinking quickly, he drove over to the Kinzie Street Bridge, looked down at the river, and saw a whirlpool. He reported his find on the air and city vehicles of all stripes descended on the site within moments.

Lots of Water and Lots of Money Go Down the Drain

A 1910 map of the Chicago Tunnel System shows just how far the waters of the Chicago flood reached. Image via Wikimedia

Contractors dug an emergency hole and filled it with debris and concrete to stop the flood. Supposedly, workers even flung mattresses into the river in the hope that the suction would block the breach. I can only hope that was true! But 250 million gallons of river water had already rushed through the tunnels. Those waters could have shorted out sub-stations and power lines, collapsed the Grant Park North parking garage, and destroy merchandise and records in basements. Because of these dangers, all non-emergency workers in downtown were evacuated for their own safety.

Eventually, workers drained the flood waters into the Deep Tunnel System. But businesses had suffered nearly $2 billion in damages due to waters that got up to 25 feet deep. Some of the images from that day are surreal. According to reports, the Thompson Center’s atrium was so flooded that furniture from the food court was floating around. I wonder if there were any soggy Sbarro’s breadsticks in there…

Fingers were immediately pointed, and investigations eventually blamed the City of Chicago itself for the flood. They had not inspected or repaired the tunnels and leaks despite plenty of warning. Hilariously, the contractor whose work set off the whole fiasco got a light penalty because of the vagaries of Admiralty Law.

Fortunately, we have not had a repeat flood since then. The watertight bulkheads the city installed in the tunnels might have something to do with it. If you’d like to learn more about Chicago’s many layers, we explore some of the areas affected by the Chicago flood on the Loop Interior Architecture Walking Tour.

- Alex Bean, Content Manager and Tour Guide at Chicago Detours