A second deep shaft is being dug at Avondale and Lavergne avenues as part of the next phase of the project to replace the Lawrence Avenue sewer in Jefferson Park. View Full Caption DNAinfo/Heather Cherone

JEFFERSON PARK — Drivers should avoid traveling west on Montrose Avenue once crews begin the next phase of a $20 million project to replace a 100-year-old sewer to keep Jefferson Park homes from flooding.

Westbound Montrose Avenue will be closed to all but local traffic between Cicero and Lavergne avenues from May 4 to Sept. 1 as crews replace the crumbling sewer underneath Montrose that has flooded area basements during strong storms and connect it to the city's Deep Tunnel.

"People should avoid the area if possible," said Owen Brugh, chief of staff to Ald. John Arena (45th). "It is going to be a mess."

Drivers should follow the posted detour signs and take Cicero south to Milwaukee Avenue and then head west on Montrose, Brugh said.

The No. 78 Montrose CTA bus will be rerouted south on Cicero to Irving Park Road and west to Laramie Avenue before heading west on Montrose, Brugh said.

Additional officers will be assigned to patrol the area to enforce traffic restrictions, and rubber speed humps will be used to prevent drivers from using side streets such as Sunnyside Avenue to bypass the construction, Brugh said.

While the work will certainly inconvenience residents and those who commute through the area, Brugh said the project would result in a "significant reduction in basement flooding for homes in Jefferson Park when it is all over."

The project started nearly a year ago when crews began digging up Lawrence Avenue to reach the sewers and Deep Tunnel. Lawrence Avenue was closed at Lavergne Avenue from September to December.

Since December, crews have been working at Avondale and Lavergne avenues and at Montrose and Lavergne avenues as part of the second phase of the project. Those intersections have been closed since the work began.

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