From where contractors work 60 feet underground at the end of the westside diversion tunnel, a pinprick of light can be seen to the south, the next drop shaft at Dover Court in Davenport.
From the site at Williams Intermediate School on Division Street, Dover Court is about 1,500 feet away “as the mole crawls,” joked City Administrator Craig Malin. The city showed off the project Monday after it recently reached a milestone.
Tunneling for the $22 million second phase of the sewer project was complete last month. For John DiPonio, project manager for Jay Dee Contractors, the project should be further ahead. The project is still ahead of schedule because Phase II was to be completed by July 2013 but now is scheduled to be done next March.
“It has been challenging for us,” DiPonio said, standing in the oak-ringed tunnel. “If I look at my last schedule, we should be out of here by now.”
Residents waiting for streets to reopen have to be patient.
“They still have the pipe to put in and manholes to build,” said Tom Leibhart, a Public Works engineer assigned to the project. Sewer pipe has been installed as far north as Pleasant Street.
The 8-foot diameter of the tunnel will be filled with sewer pipe that has an interior diameter of 5 feet and exterior diameter of 6ƒ feet. Concrete will be used to grout the pipe segments and fill the rest of the tunnel. Street work will be done next spring.
Alderman Ray Ambrose, 4th Ward, thanked neighbors.
“They made a lot of sacrifices for this project,” Ambrose said of neighbors who live near the tunnel’s five drop shafts.
The final phase will begin about the time the second phase is finished. The third phase will run the tunnel under Duck Creek to a trunk line near Silver Creek.
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The project was delayed briefly earlier this year when an aquifer was discovered in the tunnel’s path. Soil borings showed the aquifer to be a significant obstacle. To solve the problem, the contractor bored 21 wells and pumped tens of millions of gallons of water out of the aquifer during tunneling. About a dozen pumps are still running.
“This is world-class work from a world-class contractor,” Public Works director Mike Clarke said, standing in the 8-foot-tall shaft near the school.
On the surface, Mayor Bill Gluba said the benefits of the project are seen and unseen. He pointed to new roads and sidewalks along Howell Street just north of River Drive and to the improved infrastructure that will make development easier in the northwest part of the city.
“You’ll see new development out here in northwest Davenport when it is complete,” Gluba said of the diversion tunnel. “You have to have sewers. They’re not glamorous to talk about, but they are vital to the health and development of the city.”