Why Can’t La Grange Rely On Deep Tunnel?

LA GRANGE, IL – With La Grange’s flooding woes, one may wonder why La Grange doesn’t make greater use of the much-vaunted “deep tunnel,” rather than deal with years of litigation with a quarry that the village largely blames for its drainage issues.

One resident posed that very question to Patch on Wednesday: “Have you ever asked La Grange officials why we have to go through the quarry when we have access to the deep tunnel at Cossitt and East? It would cost more money, but could be done without litigation.”

The Metropolitan Water Reclamation District, which includes La Grange, maintains the deep tunnel, to which the village already has connections.

At Monday’s Village Board meeting, a district official explained why the deep tunnel is not the easy solution that it may seem – at least for now.

The deep tunnel runs from Wilmette to the reservoir just south of La Grange. A few times a year, it fills up during storms, said Kevin Fitzpatrick, the district’s assistant director of engineering.

“The tunnel and reservoir are designed to capture sewage that otherwise would end up flowing into waterways or backing up into people’s basements,” he said. “So what happens through the deep tunnel, as big as it is, it still fills up a handful times a year. We are expanding it. The expansion won’t be completed until 2029.”

Now, the reservoir can capture 3.5 billion gallons of water and the tunnel 1.2 billion gallons, Fitzpatrick said. After a storm, he said, the district runs the water as fast it can through its treatment plant.

When the system fills up, connections are closed. That way, he said, water doesn’t flow to lower-lying areas, including Chicago and Cicero.

“We treat everyone the exact same,” Fitzpatrick said. “When it’s closed, it’s closed. Whatever we can take, we take. It’s available until it fills up.”