Special Supplement • Autumn 2012
White Point Slide Report Affirms Natural Causes for Slide by: Terelle Jerricks, Managing Editor
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arly this past summer on June 18, Los Angeles City Councilman Joe Buscaino’s office released an engineering report on the White Point slide, which took place in December 2010, that affirmed it was the result of erosion and not of any one particular factor. Another morsel taken from the hour-and-half long meeting: neighborhood residents are about evenly divided on what to do about Paseo del Mar, the street marred by a huge hole in the ground. Councilman Buscaino scheduled the community meeting that included City Engineer Gary Lee
A road through the interior of the Preserve would be an irreplaceable loss of a great public space that has been beautifully preserved and restored over the past decade. Moore and others from his office to discuss the long-awaited report that was only put online the following morning. Moore talked about the 800-page report, focusing on the maps that used data collected from dozens of monitors and core samples, and turning the community meetings into a lecture on geology and soil erosion mixed with a bit of humor. Moore presented multi-colored maps depicting the site of the slide, historic slide areas and dormant areas, as well before and after photos of the slide area. Shannon and Wilson Inc., the consulting firm hired to study the slide site, drilled core samples 100–feet into the ground and sent a camera through the holes and other instruments to gather data on what direction, if any, the ground was moving. The assessment: “All the readings since December shows virtually no movement in any of the shaft sites,” Moore said.
Moore explained that water and gravity were important variables causing the slide. He said that the soil in the western part of the site was saturated with water. At the same time, the consultants couldn’t pinpoint leaky sewer lines, broken water pipes, or excessive irrigation as the cause of the extra water, except to note there was some extra rain. “From December to May, we’ve seen an increase in groundwater,” Moore said. “We want to know if it’ll go down over the summer. It was 15 feet higher now than in December.” Moore then focused on the sediment on the site and noted that the report’s authors didn’t detect movement through that analysis either. “Before the land moved, alta mira shell was the predominant soil and bentonite clay,” Moore said. “Clay is very slippery. With the modeling done by the consulting team, the top area was filled with water and gravity caused the slide.” The report states that not any one reason was the cause, but all were contributing factors. According to the report, there were no utilities, or irrigation on the nature preserve and the Nike missile base was ruled out as a cause by the cityhired consulting firm. In the meantime, the city plans to install more monitoring wells and drainage ditches to remove excess water. This in addition to cleaning up the area by getting rid of the storm pipe and the broken pieces of asphalt falling into the ocean. There was also discussion of installing a slope anchor system to reinforce the slide area, as well as make traffic improvements to ease traffic and speeding. Rep. Janice Hahn sent a letter to Col. Mark Toy of the U.S. Army Corps of Engineers to seek federal assistance in recovery and prevention efforts, a follow-up to his invitation to the slide area in April 1. At the time, he said the only way the Army Corps of Engineers could get involved is if it was found that the slide was the result of long-term coastal bluff erosion. “I’m calling on the Corps to provide its expertise in strengthening the bluff to prevent a future landslide,” Hahn wrote in the letter. “When we toured the landslide earlier this year, you indicated HarboRLiving
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that the U.S. Army Corps of Engineers could become engaged – and there could be potential federal funding — in the landslide recovery and prevention efforts if coastal erosion was determined to be a cause of the landslide.” For the long term, discussions revolved around five different options: • Installing earth anchors that are bolted from the beach side on Weymouth and Paseo del Mar. Officials said it shouldn’t be too aesthetically intrusive. • Abandoning the roadway is an option that would save $1 million. (Already $7 million has been spent on studies and fences) • Grading the roadway and putting in a dip like Portuguese Bend. The drawback is high maintenance costs. The possible solution would cost $50 million. • Restoring the road, supported by a retaining wall. The cost is $27 million. • Building a bridge over the hole would be the most expensive option at $60 million. Palos Verdes Peninsula Land Conservancy has been working with the community on the landslide issue as a member of the San Pedro Coastal Neighborhood Council’s ad-hoc Landslide Committee. The Conservancy’s executive director, Andrea Vona, in a released statement said that while the Land Conservancy is excited about the options for creative land use and more permanent solutions for the coastline impacted by the landslide, they were opposed to a road being diverted through the interior of the Nature Preserve. “A road through the interior of the Preserve would be an irreplaceable loss of a great public space that has been beautifully preserved and restored over the past decade,” Vona said. Indeed, rerouting the road across the Nature Preserve would be problematic because the road could only be open during hours the park was
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