WGN-TV CoverStories: Deep Tunnel
October 10, 2005
It's a bit of Chicago history in the making, some 300 feet underground. Just days from now, the final section of Chicago's deep tunnel project will be complete.
And flood water and sewage that might have found its way into your basement will instead be channeled deep below Cook County.
A rock wall, about as thick as the distance from me to you is all that stands in the way of completing the last section of the deep tunnel project, the longest, most ambitious, and most expensive public works project in Chicago history.
From the outside, it doesn't look like much. Some old construction material, a few cranes and a big hole in the ground.
"So I figured there would be an elevator that lowers us, but this isn't how it works."
"This is the elevator. We're actually going down into a vent shaft," says Terry O'Brien, president, Metropolitan Water Reclamation District.
A shaft that drops some 300 feet into the earth. It's a long way down, and it looks like an even longer way up. It's truly a deep tunnel and finally the cage lands near a dramatic cathedral-like dome where four tunnels converge.
"If you look up about a 100 feet you'll see the tunnels that were just mined. Those are two 18-foot diameter tunnels and the spillway," O'Brien says.
They're empty now, except for workers putting the final finishing touches on the project. But just wait until the next big rain.
So at some point in the near future, this will be under water?
"This will all be under water, it'll go as high as those two tunnels up there," O'Brien says.
But why spend 30 years and $3 billion carving out miles of rock?
"We're picking up the outflows during a heavy rain event that normally would have flowed into the inland waterway system and polluted that waterway system. Now, we've actually created an underground river to capture that raw sewage and then to run it through the normal treatment like we do on a dry weather day," O'Brien says.
It's a massive underground river.
One hundred and nine miles stretching throughout Cook County. It's a one of a kind engineering marvel. And it's almost finished.
On the other side of this wall the deep tunnel project will come to an end when engineers blast through 21 feet of solid rock to join another tunnel. It should be a very dramatic event, but amazingly, no one will be here to see it.
But they'll hear it. Engineers say it'll take about three controlled explosions. That'll open the pathway to this nearby reservoir that will eventually hold 8 billion gallons of dirty water keeping it separate until it can be cleaned and re-circulated.
"We've got 68 different species of fish now in the inland waterway system. People are building their front doors facing the river now rather than their back doors. We've got boat traffic along the inland waterway system. We've got canoeists, kayakers. Everybody's now taking advantage of what we call the second lakefront in the Chicagoland area," O'Brien says.
Chicago proved itself as a clean water pioneer a hundred years ago when we reversed the flow of the river to keep sewage out of the lake. Now we're the only metropolitan area that's using this unique tunnel and reservoir technology to keep the waterways clean. In fact, even though the entire system won't be online for another 10 or 15 years, other waterfront communities are already taking notice and asking for advice on similar plans.
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