The stormwater diversion tunnel runs 150 feet below Foster Avenue. View Full Caption Chicago Department of Transportation

ALBANY PARK — The $70 million Albany Park Stormwater Diversion Tunnel is the coolest-looking piece of infrastructure people will never get to see.

The newest image, snapped 150 feet below Foster Avenue, shows crews constructing the tunnel's liners, which will be used to mold the pipe's poured concrete.

Excavation of the 5,833-foot tunnel — which connects an inlet shaft near Springfield Avenue with an outlet shaft in River Park — was completed in September.

The contractor expects to begin pouring concrete this week continuing into November, according to the Chicago Department of Transportation.

Once the tunnel becomes operational, sometime in spring 2018, the pipe, 18 feet in diameter, will divert overflow from the Chicago River away from homes in Albany Park and North Park, releasing the water into the North Shore Channel downstream.

The tunnel was announced in 2013 after flooding that saw residents evacuated by boat. Construction began in 2016.