Washing Out to Sea : Recent storms have apparently accelerated landslides along some coastal bluffs of the Portuguese Bend area of Rancho Palos Verdes.

Torrential rains earlier this month have caused havoc along the main east-west route through the Portuguese Bend landslide area of Rancho Palos Verdes, and there are signs that the rains have accelerated the pace of the old landslides along the coastal bluffs south of the road.

Long sections of Palos Verdes Drive South have sunk five feet or more, causing cars to lurch and bump through the damaged area.

“Between Inspiration Point and Portuguese Point (the landslide) has accelerated. . . . You can see where (the road) is moving,” said geologist Perry Ehlig. Large cracks, rips and slumping pavement mark the new slide movement, he said.

Even more worrisome, he said, has been the loss of nearly half the massive rock barriers placed in the ocean at the foot of the bluffs in Portuguese Bend. Storm-driven seas have torn away large sections of the rock barricades put there to protect the south-facing cliffs from wave erosion.

“You can see the erosion in the cliffs since the storms hit. They are in pretty bad shape,” said Ehlig, a professor of geology at Cal State Los Angeles, and the city’s consulting geologist.

The storms dumped nearly six inches of rain on the Palos Verdes Peninsula in 10 days and caused extensive road subsidence and cliff erosion; but Ehlig said the news was not all bad. There has been no measurable trouble in the mid-to-upper regions of the two-square-mile Abalone Cove-Portuguese Bend slide areas, he said.

The slide action in those areas has been slowed and nearly stabilized by previous city efforts, Ehlig said.

Most of the attention is now focused on the bumpy road and the loss of at least half the rock barriers in the financially strapped, upscale bedroom city of 42,000. Already facing a $3-million budget deficit, the city doesn’t have the resources to make needed repairs, and city officials say all they can do is take a Band-Aid approach and hope for the best.

Repairing and realigning the mile-long section of road could cost up to $1 million, officials estimate. The city has $56,000 budgeted for such work, and no money is available to replace the rock barriers referred to as “gabion structures.”

“All we can do is patch the road and slow traffic, reduce the speed limits through the area,” said George Wentz, a city redevelopment agency engineer. As for the gabion structures, he said, “we can’t afford to replace them. There’s no money in the budget.”

If the structures are not replaced, experts say the erosion will only get worse, resulting in yet more damage and costly repairs.

The landslides started in 1956, triggered by a complex mix of unstable geologic conditions, the impact of urban development and heavy shoreline erosion caused by wave action, according to experts.

Geologically, the slides occur when a thin layer of waxy clay called bentonite, which sits between the bedrock below and the landmass above, becomes wet. The bentonite acts like a lubricant, greasing the skids under the heavy weight of earth and rock above. If the bedrock formation slopes down, it acts like a slide. The results can be disastrous.

More than 200 homes have been damaged or destroyed by the slow-moving slides over the past 36 years, reports show. The city has spent millions of dollars to stop the slippage that has already moved houses and roads hundreds of feet seaward.

Federal experts say an all-out effort to stop the slides completely could cost up to $60 million, and may not work.

Most of that cost would go to erecting a permanent seawall to stop all wave action against the cliffs, a $20-million project that would almost certainly trigger protests from environmentalists and those who enjoy the sight of a rugged seacoast.

Short of money and in a hurry to slow the slides, the city installed 2,300 feet of gabions, finishing the job last year. Installation of these giant wire cages filled with tons of rock cost $450,000, but the barriers failed to pass muster during the recent storms, city officials acknowledged.

“Unfortunately a significant amount of the damage has occurred to the structures due to waves powered by the latest winter storms,” Catherine Reed, director of public works, told the City Council earlier this month. The loss of long sections of these rock barriers is allowing waves to tear away more of the cliffs.

Ehlig and Wentz both said they expect the increasing cliff erosion to speed up the landslide in the bluff area. Over the past year the slide area has been creeping along at 14 feet a year, up from 10 feet during all of 1990, Ehlig said.

Since the slides began 36 years ago, sections of the original Palos Verdes Drive South have moved 700 feet down, toward the eroding cliffs. Chunks of the old roadbed have fallen into the sea.

In 1987 the city spent $900,000 to move the road back up the slope to its original alignment, officials said. Then, over the next two years the city spent as much as $250,000 a year repairing recurring damage to the mile-long section that crosses through the slide zone. Such repairs are now too costly, officials said.

Even if the city had the money, City Manager Paul Bussey said, it wouldn’t be prudent to make major repairs because the damage is continuing. It is better just to patch up the damage and wait until the city can find a permanent solution for the slide problems, he said.

Legacy of February’s Storms The disastrous rains earlier this month have caused large sections of Palos Verdes Drive South , the main route through the Portuguese Bend landslide area of Rancho Verdes, to sink five feet or more. Storm-driven seas have also torn away sections of the gabions, or rock barricades, installed at the foot of nearby bluffs to protect the cliffs from wave erosion.