Ala Wai Sewer Project Update – Microtunneling Pit Work Continues

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Contractors made significant progress on the two pits that will be used to launch and receive a special microtunneling machine under the Ala Wai Canal and Kaiolu Street in Waikiki.

Workers poured a concrete floor in the mauka pit, located near the Ala Wai Community Gardens. A final pour is scheduled this week. Next week workers expect to lower a special ten-foot long machine into that pit, and prepare to tunnel underground, pulling with it a series of new wastewater pipes pushed with jacks from behind.


Excavation continues in the makai pit, at the corner of Kuhio Avenue and Kaiolu Street. Two walers have been installed, a third will be installed in the coming days. This is the pit that will receive the microtunneling machine, and hook up the pipes to the Beachwalk Pump Station.

Workers also continued jet grouting operations on Kaiolu Street to strengthen the subsurface soils before the sewer pipe is installed below ground.

Jet grouting involves drilling deep holes and installing underground cement pillars. The jet grouting on Kaiolu Street will run typically from 6am to 6pm with occasional later shifts to finish jet grout columns in progress.

On Friday, Jan. 26, workers conducting jet grouting hit a lateral water pipe, causing a temporary interruption in water service to one condominium on Lewers Street. The pipe was repaired, and water service was restored early Saturday morning.

Some Kaiolu Street residents initially thought it was another break in the sewer line, bringing back memories from last March when an aging sewer pipe burst, resulting in the discharge of 48 million gallons of wastewater into the Ala Wai Canal. But it was a secondary water line that broke this time, and no sewage was discharged.

The big sewage break last March triggered the Beachwalk Wastewater Emergency Bypass project, launched last May.

The BWEB project has already resulted in the construction of a temporary bypass line that can be activated in the event of another break in the aging sewer line. Those pumps and pipes along both sides of the Ala Wai Canal are temporary, and will be removed once the permanent line is finished this summer.

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