City breaks ground on wastewater force main project

In 2006, eight years ago Monday, roughly 48 million gallons of sewage spilled into Ala Wai canal after a force main broke under Kaiolu St. The spill triggered mass health concerns and tainted several beaches in Waikiki.

Now, the city is unveiling a new system to make sure something like that doesn’t happen again. After the original pipe broke, a backup second pipe was put into service. This latest project involves a third and even a fourth backup that connects Ala Moana Wastewater Pump Station to Sand Island Wastewater Treatment Plant.

“(Force mains) one and two are in existence right now,” said Lori Kahikina, Dir. of Environmental Services. “One is going to be eliminated, and two, three, and four are going to be operational once they are complete.”

“It’s about greater capacity,” said Honolulu Mayor Kirk Caldwell. “We’re going to have two pipes, five feet in diameter… side by side going right underneath Honolulu Harbor channel.”

The city says 70 percent of the project is already done, though the most difficult part is still to come. Microtunneling requires crews to go more than 100 feet down and 1,400 feet across the channel, the entrance and exit to Honolulu Harbor.

“Almost what you would compare to arthroscopic surgery, where a shaft is made and you tunnel between shaft to shaft, and it could be a half mile of whatever that case may be, so it’s not too intrusive to the environment,” said contractor Franco Coluccio.

Force mains three and four cost about $118 million and is part of a nearly $5 billion grand plan to bring Honolulu’s sewer system up to federal compliance.

Much of that cost will be paid by taxpayers through increases in sewer fees over the coming years, including a four-percent increase effective July 1.

Officials say the work will not affect park usage or traffic.

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