KAILUA, OAHU (HawaiiNewsNow) - The city's biggest ever sewer tunneling project will soon cut an underground hole from Kaneohe to Kailua. The ten-foot-wide pipe meets the mandate ordered by federal agencies to upgrade Oahu's wastewater collection.
"We have spills on the windward side because the system is sometimes up to capacity, especially during the winter season when it rains a lot. This is going to provide huge capacity," Department of Design and Construction director Chris Takashige said.
It will stretch for three miles and pass under Kalaheo Hillside. Some residents along the route worry about ground shifts and rock slides.
"The area has had a history of some instability in the soil. So the residents there are very concerned that this might aggravate that," Kailua Neighborhood Board chairman Chuck Prentiss said.
Takashige said most of the tunnel boring will be 200 to 300 feet under ground.
"From all the experts that we've talked to, essentially people are not even going to know we're working," he said.
Healani Gardens residents urged the city to move the tunnel farther from their Kaneohe town homes.
"If they're drilling several hundred feet below, we just want to make sure that the hillside doesn't come tumbling down," Annika Seavey said.
Planners rerouted that section.
"We did move it out," Takashige said. "It actually moves almost directly under the mountain range there through the Board of Water Supply property."
During the digging the city will use sensors to measure ground vibration and noise.
"If there is some kind of a problem with some of the houses sliding, then they would have to legally prove that it was because of the tunnel. The city might say it's some other reason," Prentiss said.
The city has used public meetings and PR firms to counter community concerns. That will continue.
"We've taken extra steps, moved the tunnel away as far from the residential areas as we could," Takashige said.
A contractor should be chosen next month. Work will begin soon after that.