LINCOLN SQUARE — Three years after the city announced plans to build a stormwater diversion tunnel to alleviate flooding in Albany Park and North Park, construction is about to start on the underground channel.
Fencing erected on the east side of River Park signals prep work in advance of equipment mobilization, the Chicago Department of Transportation confirmed.
The area, near Foster and Francisco avenues and normally home to a baseball and soccer field, will be closed off for two years while it serves as the staging site for the project's tunnel borer and other machinery.
Nearby residents can expect the occasional explosion — which city engineers said sound like fireworks and cause noticeable vibrations — as crews blast through rock to create the tunnel's 150-foot-deep outlet shaft.
The boring machine will be lowered down the shaft and chew its way west underneath Foster, 50 to 75 feet a day. The dirt and rock the machine eats up will be carted back to the surface at the outlet shaft.
The city devised the $50 million tunnel scheme following three "100-year" floods of the Chicago River in 10 years, which saw some North Side residents evacuated from their homes via boat.
When the river approaches dangerous levels, the tunnel will make use of gravity to funnel overflow water, via an inlet shaft near Foster and Springfield avenues, below ground to the outlet shaft in River Park, where the water will rejoin the North Shore Channel.
Once completed, the tunnel will be 18 feet in diameter and a mile long but its only visible elements will be the inlet and outlet shafts.
The affected section of River Park, which will serve as the main construction site for the Albany Park Stormwater Diversion Tunnel. [Chicago Department of Transportation]
Because the property surrounding the outlet shaft is larger than the inlet area to the west, River Park was designated the main construction site.
At the conclusion of the project, the section of River Park will be restored with a new soccer field and regulation-sized baseball field.
A permanent control center will be built at the outlet shaft, with a design expected to mimic River Park's fieldhouse.
During construction, the River Park bike path will be rerouted from its existing underpass at Foster Avenue. A temporary trail crossing, with a signal, will be put in place at Foster for pedestrians and cyclists.
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