The landslide 35 feet below Asilomar Boulevard in Pacific Palisades has moved more than a foot in the past five years, according to ongoing measurements by the City of Los Angeles Bureau of Engineering. In 2006, the bureau began installing 10 inclinometers (which measure ground movement) in and around the ongoing landslide at Asilomar, just west of El Medio. From these instruments, engineers have determined that a portion of the ocean side of Asilomar Boulevard (between Puerto del Mar and Wynola Street) has moved a foot vertically since 2006. In response to this movement, the City recently used sand and cement slurry to fill the cracks and expanding sinkholes that catacomb the ground on the south side of Asilomar. According to Bureau of Engineering spokeswoman Tonya Durrell, this was done to prevent people from falling into a sinkhole. Some holes, photographed by the Palisadian-Post before the infill, were large enough to contain a dog or small child. ’They were also filled in to prevent runoff from flowing into the soil along the bluff during periods of heavy rainfall,’ Durrell added. The Post asked engineers if there was an urgency to find a fix for Asilomar, given the collapse of the Paseo del Mar roadway in San Pedro on November 20. A Los Angeles Times story (‘San Pedro Landslide Called ‘Life-Threatening Hazard,” November 15) stated: ‘A slow-moving landslide on a coastal bluff in San Pedro is worsening, exposing huge, deepening crevices along a seafront roadway and dropping chunks of earth and concrete into the ocean.’ Five days later, 600 square feet of dirt and road tumbled off the San Pedro cliff on a rainy afternoon, leaving a section of the road in ruins. City engineers told the Post in a December 6 e-mail that ‘In July of 2011, cracking was observed in Paseo del Mar and grew quickly until November, when a large portion of the roadway was destroyed.’ They noted there is a difference in Pacific Palisades because, ‘the Asilomar landslide has been moving very slowly for many years.’ E.D. Michael, an independent geologist who specializes in engineering geology, hydrogeology and forensic geology, warned the City of eminent danger on August 15. The Post queried him about the infill of the sinkholes. ’It is an active landslide and filling cracks will not stop it,’ Michael wrote on December 1. ‘As movement continues, and it will, the patched cracks will again open, allowing runoff to enter. Filling them is only a temporary measure and extends somewhat the period before a massive failure occurs. ’However, the cause of the slide is the mechanical effect of groundwater that enters the subsurface north of Asilomar Boulevard,’ Michael continued. ‘A rational approach would be to perform an area-wide hydrologic equilibrium analysis as a basis for determining the feasibility of dewatering [in the adjacent residential neighborhood]. ’Such a study should consider not only the possibility of physical dewatering, but also the sources of the ground water, which could include infiltrated rain, excessive domestic over-irrigation in gardens and yards, subsurface inflow’generally from north of Sunset Boulevard’and leaking water mains in streets.’ According to spokesperson Durrell, City engineers have found water on the site, but say it is unknown as to what is actually causing the landslide to occur. (In addition to the slide at 35 feet, there is another at 90 feet down the hillside.) ’The movement that has caused the damage appears to be along the plane that is 35 feet deep,’ Durrell wrote. She noted that the repair cost for the entire landslide quoted in the Ninyo and Moore report (a 2008, 212-page geotechnical evaluation on the Asilomar bluff) is approximately $26 million, and added: ‘The City is currently working to develop a more economical method of stabilizing the road.’ According to Durrell, there has always been an urgency to address the stability of the landslide, but taking action has been complicated by the fact that the land has joint ownership between Los Angeles and the two mobile-home parks below Asilomar: Palisades Bowl and Tahitian Terrace. According to Norman Kulla, Councilman Bill Rosendahl’s Northern District Director, a less costly repair’focused entirely on City property (Asilomar)’is under evaluation. ’Subject to City Council approval, we have identified funding to perform a geotechnical investigation to determine if such repair is feasible, and if so, then proceed to design,’ Kulla said.
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