Anon remembers when Chicago flooded
The Chicago flood occurred on April 13, 1992, when repair work on a bridge spanning the Chicago River damaged the wall of an abandoned and disused utility tunnel beneath the river. The resulting breach flooded basements, facilities and the underground Chicago Pedway throughout the Chicago Loop with an estimated 250 million US gallons (1,000,000 m 3) of water.
https://en.wikipedia.org/wiki/Chicago_flood
The Tunnel and Reservoir Plan (abbreviated TARP and more commonly known as the Deep Tunnel Project or the Chicago Deep Tunnel) is a large civil engineering project that aims to reduce flooding in the metropolitan Chicago area, and to reduce the harmful effects of flushing raw sewage into Lake Michigan by diverting storm water and sewage into temporary holding reservoirs. The megaproject is one of the largest civil engineering projects ever undertaken in terms of scope, cost and timeframe. Commissioned in the mid-1970s, the project is managed by the Metropolitan Water Reclamation District of Greater Chicago. Completion of the system is not anticipated until 2029,[1] but substantial portions of the system have already opened and are currently operational. Across 30 years of construction, over $3 billion has been spent on the project.
https://en.wikipedia.org/wiki/Tunnel_and_Reservoir_Plan