Clearwater update reports initial entry area is ‘stable and intact’

With a first-hand inspection of the initial portion of the underground tunnel for the Clearwater wastewater pipe project now complete, conditions in the three-mile space ahead of the breach area appears to be stable, according to a Thursday, Feb. 5, update from the Los Angeles County Sanitation Districts.

“The inspection along the completed tunnel indicates it is stable and intact,” the report said. “As a result, Cal/OSHA has authorized a second phase of re-entry to allow inspection of the tunnel to within 150 feet of the breach area so the investigation and engineering assessment for repair and recovery can take place.”

Drilling activity on Western Avenue near Fifth Street in San Pedro, meanwhile, “remains ongoing to assess the conditions above the breach at approximately 350 feet below street level.”

So far, the investigation has remotely identified an empty space about 10 feet by 20 feet in size, located about 310 feet below ground level at the breach site, according to the report.

Crews have been relying on a remotely operated vehicle and drone technology to learn more about tunnel conditions near the breach.

“The contractor is drilling multiple bore holes to better understand underground conditions and determine the best method for filling and reinforcing the underground area,” the latest report said. “Monitoring of movement at the surface has detected no significant movement at street level. Drilling and street activity is expected to continue with longer working hours during the day to help this effort progress.”

The underground conditions, however, has made drilling difficult, the report added. The breach occurred below Western Avenue near where Fifth Street would connect.

The in-person inspections were approved in December and teams have since gone about three miles in from the entrance adjacent to the A.K. Warren Water Resource Facility on South Figueroa Street, north of Lomita Boulevard, to restore ventilation, establish power and inspect the tunnel’s structural integrity.

It was the first time inspectors entered the tunnel since the July 9 underground breach temporarily trapped several workers, halting the project to install new regional wastewater pipes.

Early underground pictures proved difficult to capture.

The entire length of the tunnel from Carson to San Pedro — about seven miles — will be carefully inspected before work on the final leg of tunneling can resume, officials have repeatedly said.

The breach temporarily trapped 31 workers. Collapsed material largely closed off the tunnel, but workers, traveling through the tunnel on a tram, were able to climb over the top of the fallen sediment pile, where there was still space. All were rescued, with only a few minor injuries reported.

The tunnel boring machine being used in the project remains trapped underground just ahead of where the breach occurred.

The ambitious, $630 million, multiyear Clearwater Tunneling Project launched in 2019 and was more than a decade in the works, requiring extensive planning with advance and ongoing community outreach. Work had progressed without problems until the breach, which occurred about five to six miles from the only above-ground access point in Wilmington to the north.

Tunneling was not done under homes or other buildings but instead followed only under streets. The project was on the last leg of its journey when the breach occurred.

The older, smaller underground wastewater pipes, meanwhile, remain in place and are still working, officials have said.

“The contractor is drilling multiple bore holes to better understand underground conditions and determine the best method for filling and reinforcing the underground area,” the new report said. “Monitoring of movement at the surface has detected no significant movement at street level. Drilling and street activity is expected to continue with longer working hours during the day.”

Updates and changes to drilling activity are posted on the Clearwater Project website.

Construction at Royal Palms Beach — where the line ends — was also suspended in August following the discovery of Native American artifacts.

But on Jan. 21, the Clearwater report said, the State Historic Preservation Office authorized Royal Palms Beach construction activities to resume after a five-month archeological investigation. Limited construction work at that location will involve drilling shoring piles.

That work is expected to resume in the next few months. The site is being prepared to eventually connect to the new Clearwater tunnel when it is completed.