Engineers Still Investigating Cause of Latest Rambla Landslide

• Tentative Assessment Focuses on Possible Impact of Private Downslope Grading in the Area

BY BILL KOENEKER

A landslide and subsequent failure of Rambla Pacifico Road that occurred on Feb. 5 between Azurelee Drive and Las Flores Canyon Road is being tentatively attributed to a work crew performing grading work below the roadway for a driveway and residence, according to Los Angeles County authorities.
“It is difficult to assess. It is currently still under investigation,” according to John Kelly, who is the deputy director for the county Public Works Department, which oversees the unincorporated area of Malibu where the slide is located.
The road collapsed and is completely closed. The impact to hillside residents is minimal since it does not block homeowners going south to Pacific Coast Highway, but provides an impediment to about 20 residences south of the slide who are going northward and must detour. However, the road provides an alternative route during disasters. The roadway is expected to be repaired by June, according to Kelly.
The public works spokesperson said the private party is expected to complete slide remediation and restoration and offer a fix for the road.
“Our first order of business is to deal with the slope failure. [The owner] is submitting plans to repair it,” Kelly said.
The construction crew was grading into the hillside in what is called a “back cut,” which is believed to have ultimately caused the failure, Kelly said.
The permit allowed 26,000 cubic yards of grading. There is still no estimate of how much slide material was involved, explained Kelly, who said the California Coastal Commission is also involved in overseeing the restoration. The applicant had permits from the county and the coastal agency.
The public works spokesperson said it no longer seems feasible that the water main was leaking and contributed to the problem as initially reported. The Las Virgenes Municipal Water District’s water main was under the road. The slide took the pipe with it and a bypass line had to be installed.
“All I can really say is the exact cause is being investigated,” said Kelly, when pressed to explain why leakage had tentatively been ruled out.