Chicago flood

Rehabilitation work on the Kinzie Street Bridge crossing the Chicago River required new pilings.

One of the pilings on the east bank was driven into the bottom of the river alongside the north wall of the old tunnel.

After some weeks, most of the clay between the water and the breach had liquefied, which rapidly increased the rate of flooding in the tunnel.

The water flooded into the basements of several Loop office buildings and retail stores and an underground shopping district.

The Loop and financial district were evacuated, and electrical power and gas were interrupted in most of the area as a precaution.

Monitoring police scanners, Langford heard security crews from Chicago's Merchandise Mart (near the Kinzie Street Bridge) report that the water in their basement had fish.

The concrete was placed into drilled shafts into the flooded tunnel near Kinzie Street and formed emergency plugs.

Eventually, the city assumed maintenance responsibility for the tunnels, and watertight hatches were installed at the river crossings.

[6] Today, there remains contention as to whether the mistake was the fault of the workers on-site, their parent company, or even the claim that maps provided by the City of Chicago failed to accurately depict the old tunnel systems.