Starting as soon as December, residents of a Northwest Side neighborhood are expected to hear something unusual interrupting the winter soundscape — explosions.
Crews plan to start using explosives to blast through deep-underground rock and link the sewer system to the Deep Tunnel network, said Gary Litherland, a city water management department spokesman. The subterranean explosions in the Jefferson Park neighborhood could sound something like thunder, he said.
The explosions planned near the crossing of Lavergne and Lawrence avenues are part of a broader project aimed at improving drainage and preventing basement flooding in the surrounding area, according to a city document explaining the project. The Northwest Side work, scheduled to end in December 2015 at an approximate cost of $19.7 million, will involve installing shafts to tie the sewers into the Deep Tunnel system, the massive regional flood and pollution control project that remains under construction, Litherland said.
Starting next month, workers will use conventional equipment to dig about 65 feet down, he said. Once they hit rock, Litherland said, crews will use explosives to proceed down hundreds more feet. Charges will be set off once per day.
Homeowners within 500 feet of the blast area will receive letters or in-person visits warning them about the explosions, Litherland said. A contractor will arrange for structural assessments of the homes, which will be videotaped before and after the blasts, he said.
Litherland said the chances of home damage are "very remote."
Regardless of the possibility of home damage, the chances of traffic tie-ups appear to be 100 percent. Traffic eastbound on Lawrence will be detoured onto Milwaukee Avenue and one westbound lane will be open, according to the city.
"It's probably more of a traffic issue than anything else," Litherland said.