Rain, irrigation and residential development contributed to November’s San Pedro Slide
It’s a long and inconclusive list of usual suspects that appear in the final draft report [PDF] released by the City of Los Angeles this week. The Department of Public Works tapped the Glendale geotechnical consulting firm Shannon and Wilson to investigate the slide that sent a 600-foot section of seaside roadway toward the Pacific last November.
My radio report and blog post back in April explained the slippery mix of water and soft sediment that permeates the Palos Verdes Peninsula, and what happens when too much water gets between those unstable layers of earth.
Shannon and Wilson’s report lists the following as “contributors” to the slide: irrigation — both residential and watering done inside the White Point Nature Preserve adjacent to the slide — coastal bluff erosion, precipitation, road construction and underground utilities. Just above the Preserve is a 13.2-acre complex of U.S. Air Force housing, and watering from those homes could be “influencing groundwater” near the slide. Continue reading