City digs to remove above-ground sewage pipes along Ala Wai

HONOLULU—The City and County of Honolulu has begun work on a tunneling project that will relocate a portion of an above-ground sewer pipe near the entrance to Waikiki near Ala Moana Beach Park. The above-ground piping on the mauka side of the Ala Wai Canal is also on track to be replaced with underground pipes.

The above-ground sewer pipes were installed as a precaution after a sewage line break four years ago.

In March 2006, heavy rains overwhelmed the sewers around the Ala Wai Canal, causing a pressurized sewage line to break. Days later, and after the spill was made public, then-Mayor Mufi Hannemann made the decision to divert 48 million gallons of untreated sewage into the Ala Wai Canal in an attempt to avoid having the sewage back up into the hotels and residences. The dumping caused Waikiki beachgoer illnesses and the death of one individual due to septic shock.

Last year, the City finished the Beachwalk Wastewater Emergency Bypass project and has been working on a new line that, when finished, will allow for the removal of all above-ground piping and another emergency lines on the floor of the Ala Wai Canal.

The new 5,800-foot line, called the Beachwalk Force Main, is projected to be finished in 2012. It will run underground from behind Ala Wai School to Ala Moana Beach Park.

Acting Mayor Kirk Caldwell said contractors will be able to remove a large section of the above-ground emergency pipe near the park later this year.

“We know this is of particular relief to our visitor industry, as this area is the entrance to Waikiki,” Caldwell said. “The pipes served an important purpose in that they helped ensure there would be no repeat of the March 2006 spill.”

At 5,800 feet, the new project is the longest micro-tunnel line ever built in Hawaii. Contractors will build five jacking pits that will be used to load the 72-inch pipes through the microtunneling process, so there will be no need for open trenching.

Two of the pits are under construction on Ala Wai Boulevard. Another pit will be built at Ala Moana Park and the final two will be constructed on the mauka side of the canal.

Contractor Coluccio Construction is using a silent piler that pushes rather than pounds piles into the ground to lessen the noise impact on area residents, the City said.