Repairs to Kakaʻako sinkhole expected to continue into 2023

HONOLULU – The City and County of Honolulu’s Department of Design and Construction (DDC) announced Wednesday the preliminary findings of an investigation into the discovery of a sinkhole in Kakaʻako last month, as well as plans to repair the damage and reopen the roadway to motorists, bicyclists and pedestrians.

The sinkhole, which was first reported on October 18, was quickly determined to be an immediate safety risk to motorists, bicyclists and pedestrians and necessitated the indefinite closure of the intersection of Halekauwila St. and Cooke St., where the sinkhole is located. While surrounding roads and businesses in the area remain open, the intersection is closed to traffic in all four directions and motorists are being detoured to other nearby roadways.

Shortly after initiating their investigation, DDC discovered that water was leaking from the joints of an existing box culvert storm drain beneath Cooke St., eroding sections of land approximately 14-feet beneath the surface of the roadway of the impacted intersection. The box culvert sections, which measure approximately 12 feet in width and eight feet in height, were found to have gaps at the joints, where one section is connected to the next.

Having discovered the leaks, the City contracted divers to physically enter the box culvert storm drain and conduct inspections. Those inspections confirmed that the box culverts, which are made of concrete, were still in sound structural condition and that the gaps in the joints connecting the culverts were the source of the leaking water.

The exact size of the eroded voids at the intersection of Halekauwila St. and Cooke St. are unknown at this time, but there is enough evidence to indicate that vehicular traffic should be prevented from using this section of road until the area is excavated and the voids are repaired.

“We understand the impact that the road closure is having not only on motorists, but also on businesses in the area,” said Haku Milles, the acting director of the Department of Design and Construction. “Our foremost priority is and always will be the safety of motorists, bicyclists and pedestrians, but the City is doing everything it can to make the necessary repairs and reopen the roadway as quickly as possible.”

In addition to the deploying of divers, City contractors used ground-penetrating radar to locate additional voids along the outside of the box culvert and to confirm some of the boundaries of the sinkhole.

The Department of Design and Construction is currently preparing an emergency construction project – expected to start in mid-December and last for a period of between three and six months – to repair the leaking drain culvert joints, fill the suspected eroded areas along the box culvert and repair the roadway. Following the completion of the repairs to the joints of the box culvert and sinkhole, affected sections of the roadway, sidewalks, driveways, curb ramps, curbs, and gutters will be repaired.

While the intersection itself is expected to remain closed for the duration of the emergency construction project, the City will soon be installing additional traffic signage in the area reminding nearby residents and pedestrians that the streets and local businesses in the area remain open.

Additionally, the Business and Constituent Educator team at the City’s Office of Economic Revitalization (OER) will be visiting businesses in the area in the coming days to provide additional resources to business owners and employees.

For more information on the Business and Constituent Educator team and the Office of Economic Revitalization, please visit https://www.revitalizeoahu.org/.

—PAU—