Erosion

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Water From Above and Below Likely Culprit in SoCal Landslide

Rain, irrigation and residential development contributed to November’s San Pedro Slide

USGS & Don Knabbe

Options for fixing the San Pedro Slide in southwestern Los Angeles range from several million to 62 million dollars.

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

Climate Change and Coastal Communities: Facing the Rising Tide

As the water rises, a documentary maker ponders why people aren’t more concerned

Rising seas will irrevocably change life near the San Francisco Bay. That’s the premise of RISE: Climate Change and Coastal Communities, a three-part documentary by producer Claire Schoen. The second part, “Facing the Rising Tide,” airs this evening at 8 pm on KQED Public Radio.

Opinion by Claire Schoen

Jan Sturmann

Steve Mello's family has been farming this land in the Delta for generations. Climate change may prevent his son from carrying on the family legacy.

I recently dug out an old letter which I had written to my Dad back in 1982. “Have you heard about this thing called Global Warming?” I asked.

Back in the 80’s, I was already aware of what is now referred to as “climate change.” So why is it that so few Americans understand this threat today?

In fact, America is in retreat on the subject. According to Pew Research, the number of Americans who believe the planet is warming dropped by 20 percent from 2006 (79%) to 2010 (59%). “Believe.” As if this scientific phenomenon were a belief system, a question of faith.

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Climate Change Chipping Away at the Coast

USGS: Warmer ocean temps portend more erosion along the West Coast

This week researchers at the US Geological Survey (USGS) issued a damage report that assesses how badly El Nino patterns tore up West Coast beaches during the winter of 2009-2010. Up and down the coast, the survey logged beach erosion 36% above average. The study’s authors point to the intensity of the El Nino conditions during that time, as well as a geological shift in the region of warmer water. They say high water, heavy storms and warmer waters were the culprits. And they warn that with the changing climate, these events may become more common.

“This little winter is a snapshot of what climate change may look like where we have baseline higher sea levels and more significant storms.” said Patrick Barnard, a coastal geologist with the USGS in Santa Cruz.

A sign warning of cliff erosion in Santa Cruz. (Photo: Craig Miller)

One Bay Area snapshot the authors highlighted was San Francisco’s Ocean Beach. The thin coast retreated more than 184 feet, dumping the southbound lane of the Great Highway onto the beach. It took nine months before the lane was reopened and the clean-up cost $5 million.

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