Demolition Work To Start On Sewer Tunnel
Demolition work is expected to begin this month on the long-awaited, 3-mile-long conveyance tunnel between Kaneohe’s Waste-water Pre-treatment Facility and Kailua’s Regional Wastewater Treatment Plant.
The plan is to equalize flow and help prevent overflows and spills from the system – and to fulfill part of a government consent decree to remediate Oahu sewage disposal systems over the next 25-28 years.
The city recently awarded $175 million in contracts for the project to Southland Contracting Inc. and Mole Construction Inc., plus the local construction management firm of Bowers & Kubota.
The joint venture group will begin by demolishing unused facilities in Kailua to clear the way for tunneling production and accommodations of influent pump stations.
A tunnel-boring machine will drill an opening up to 15 feet wide, clearing the way for the installation of a 10-foot diameter pipe. The gravity line will run 35 to 62 feet below ground level.
The middle portion of the gravity tunnel will be moved toward the crest of Oneawa hills, as requested by the public. The tunnel currently runs behind the Board of Water Supply reservoir near Mokapu Saddle Road.
The overall project work is scheduled in three separate phases and will take approximately five years and six months, according to a recent announcement from the city.