It’s a Boulder Dash as Workers Shore Up Coast

Perched in an excavator on the ocean side of Pacific Coast Highway at Topanga State Beach, construction worker Phil Ferree keeps one eye on the 3-ton granite boulder he’s lifting with a giant mechanical arm--and one eye on the waves crashing below.

Then he drops the boulder on top of a 1,750-foot wall he’s built to keep the El Nino-driven surf from undermining the earth beneath PCH. These rocks, he said, against that ocean: “It’ll work; for a while at least.”

While forecasters use high-tech weather tracking equipment to warn of coming storms, the California coastline’s best defense comes down to that most primitive of weapons: big rocks. California Department of Transportation officials estimate that they have spent $7.3 million so far this season to protect the state’s coastal roads with similar rock walls, built mostly in Los Angeles and Ventura counties.

Residents living farther up Topanga Canyon Boulevard have put out plastic sheets to keep the earth beneath their homes dry. Caltrans workers on Wednesday also worked at a Topanga Canyon home where water runoff had eroded a hillside and sent mud gushing onto the property during the last storm.

Ferree and his crew were working to complete the ocean wall before Wednesday night, when forecasters said 10-foot surf would hit Southern California beaches, and before an expected rainstorm moves in this afternoon.

Caltrans inspectors over the past two weeks have spotted growing evidence of erosion along the narrow stretches of earth that form the shoulder of oceanside roads such as PCH. If the dirt under the shoulder is washed away, inspectors say, the roads will collapse.

“All bets are off,” said Caltrans spokesman Vincent Moreno. “We’re about maxed out on safe distance” between the road and the surf.

In fact, there is such a demand for heavy rocks that construction crews say quarries are reporting a regional boulder shortage. With contractors clamoring for rocks faster than quarries can excavate them, some construction crews are trucking in boulders from as far east as Temecula. One contractor said Wednesday that he may use a barge to haul rocks from Santa Catalina Island.

Since Saturday, workers have dumped boulders as heavy as 9 tons each--at $40 a ton--on the Malibu sand. The lightest ones, in the 3-ton range, were piled to heights of 30 feet. The 1,750-foot wall, the contractor said, will weigh approximately 18,000 tons.

Caltrans maintenance workers are expected to inspect the wall today.

Earle Cummings, a spokesman for the state-federal Flood Operations Center in Sacramento, said the rock wall technique, known as a “rip-rap,” is “reasonably effective” as long as the rocks are big enough.

“If you can imagine the impact of a 20-foot wall of water . . . it’s pretty intense,” Cummings said. “It jams the rocks together, and they fracture. Our rocks are so small, and the sea is so big.”