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On This Day 20 Years Ago: The Great Chicago Flood

CHICAGO (CBS) On this day 20 years ago, an estimated 250 million gallons of Chicago River water poured through a crack into a little-used network of tunnels under the Loop, creating what is now known as the Great Chicago Flood.

The source of the flood was a deceptive whirlpool in the Chicago River at Kinzie Street that appeared sometime after 7 a.m. in the morning of April 13, 1992. It left water gushing like a racing rapid into the vast and antiquated web of freight tunnels that run under the Loop.

LISTEN: WBBM Newsradio's Dave Berner reports


The water flooded sub-basements of buildings across downtown. Government and business were brought to a halt when the city's main trading floors shut down and City Hall was left unable to function.

And initially, the cause was a mystery.

Downtown Evacuated; Losses In The Billions
The Loop was left in a state of pandemonium as people came to work that Monday morning.

To protect workers as utility tunnels flooded, electrical service was immediately cut from the Chicago River south to Adams and from Michigan Avenue west to Dearborn Street. Hundreds of buildings were left without power for days. But an area far greater than that – south to Taylor Street – had to be evacuated.

Thousands of people who had just arrived for work had to turn around and leave. But flooding had shut down the Dearborn and State Street subways. What is now known as the Red Line was rerouted to the Loop 'L,' but the Loop portion of the Blue Line was shut down altogether.

That left the Loop deserted, and meant millions of dollars in losses for the city's financial and retail center.

By the end of the day, the Chicago Mercantile Exchange, which had to shut down, estimated its loss at $25 billion in trading. What was then Marshall Field's lost merchandise to the waters, and the there was damage in the lower levels of the Art Institute.

In the County Building, workers saved reams of record books going back more than 100 years, and computers were stacked under a tarp in the main hallway like boxes on a moving day. But the water swallowed up millions of dollars of office supplies and duplicate records as it turned entire floors into aquariums.

The actual losses from the flood were estimated at $1.95 billion.

At the Illinois secretary of state's office at the Thompson Center – then called the State of Illinois Building – sandbags kept losses at a minimum, but the plastic chairs on the lower level food court floated about in a surreal scene.

About 1,000 restaurants had only about 20 minutes to shut down, and thousands of pounds of food had to be thrown away. City crews required many of them to submit to a health inspection afterward.

After night fall, police stepped up patrols in the dark, deserted Loop out of concerns about looting, but no serious problems were reported.

About The Flooded Tunnels
Most people know downtown is built on multiple levels, with a Pedway that allows pedestrians to walk between buildings without going outside, and tri-level city streets in some areas. But the freight tunnels that flooded in 1992 were little known.

The tunnels, which run 40 feet beneath the Loop, were dug at the turn of the 20th century for a telephone system that was never built. Instead, it was used for railroads for delivering coal, merchandise, and even mail and money between downtown buildings.

By the late 1950s, the system fell out of use, although some of its 15-mile grid was used to house high-voltage electrical conduits. Otherwise, the system was abandoned, and buildings put bricks or walls over their portals to the tunnels.

But on April 13, 1992, everyone was reminded of their existence, in the most chaotic way possible.

Repairs Take Days
Crews tried to plug the leak using gravel, cement and even mattresses. But initially, they weren't even able to find it.

On the surface that morning, a murky, dirty whirlpool full of swirling debris was all that was visible. It was too dangerous for divers, making it impossible for them to go down and find the break point until sophisticated sonar was brought in.

Workers succeeded in finding the hole, which was the size of a car. They began plugging it with stones and sandbags. Trucks lined up at Kinzie and Kingsbury streets with broken concrete, and quick-setting cement was poured on a foundation of gravel and sandbags.

But every time crews thought they sealed one hole, another whirlpool would appear a little farther from the river bank. They considered sealing off the tunnel or sinking shafts into adjacent streets on opposite ends of the bridge.

But after realizing they were in an area honeycombed with a series of utilities, they tried to construct a levee with broken concrete.

It took about 10 hours for the efforts to work. Ultimately, contractor Kenny Construction was able to plug the leak, with the help of the Army Corps of Engineers and other agencies, by drilling shafts into the tunnel where the flood had begun and placing emergency plugs inside.

The water was allowed to drain into the unfinished Deep Tunnel network, located below the freight tunnels.

Meanwhile, crews worked late into the night and for days afterward to clear the flooded basements.

Emergency workers came in from all around northern Illinois – some of them more than 100 miles away. They were pressed into service to submerge into the 35-foot deep floodwaters of the Loop basements and try and keep the rising water under control.

While some Loop businesses and institutions opened the day after the flood, most had to stay closed for three days. Some were closed for weeks.

The tunnels themselves are still now used to house power and communication cables.

Heads Roll In City Government
As crews worked to plug the sinkhole in the river, then-Mayor Richard M. Daley and other officials held multiple news conferences. Initially, Mayor Daley was annoyed when reporters asked who was to blame.

"We are not going to get into who is to blame, because we don't know as yet. That's why," Daley said. "This is a very serious problem. Don't make it funny."

But during a news conference in the 10 p.m. hour, when CBS 2's Mike Parker asked the mayor about reports that the city knew there was a serious problem in the river at Kinzie Street a week and a half earlier, Mayor Daley admitted they did.

"Yes, people did know about it before," he said. As to how long, he added, "I cannot give you specifics, but it was a number of days and a number of weeks. There was information filed within the system, not within my office. And these people are going to be held accountable. Each and every one of those persons who had information will be accountable to me and to the City of Chicago."

Within a short time, eight city officials were asked to resign or retire. Most notably among them was acting Department of Transportation Commissioner John LaPlante, who was reported to have known about the potential leak and to have been waiting for a reasonable repair estimate when the flood happened, according to published reports. Many questioned whether LaPlante deserved to be held responsible for the flood.

Ultimately, it was CBS 2's Pam Zekman who broke the story of how the flood began.

The year before the flood, wooden pilings had been put in the riverbed to protect the Kinzie Street Bridge. But they were placed in the wrong location and within the relatively short time they were there, they punctured the tunnel's ceiling.

This story was adapted from an article published on April 14, 2007, on

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