Shifting Sands to Give a Boost to Beleaguered Cabrillo Beach : Environment: The San Pedro beach will be widened by about 250 feet with sand excavated during construction at the Hyperion sewage treatment plant.

The outer portion of Cabrillo Beach in San Pedro, devastated by more than 25 years of ocean currents and winter storms, will be widened by about 250 feet thanks to construction at a sewage treatment plant nearly 20 miles away.

More than 300,000 cubic yards of sand will be excavated next fall near the city of Los Angeles’ Hyperion treatment plant in Playa del Rey and hauled by truck to San Pedro, under a plan approved by city recreation and parks officials on Monday.

The proposal needs several other local, state and federal approvals, all of which are expected by the end of January. Officials from the city, county and Army Corps of Engineers have been working on the proposal since August, 1989, when it was suggested by Harbor-area Councilwoman Joan Milke Flores.

The excavation project at Hyperion is part of a multibillion dollar effort to improve the city’s sewage treatment system. The sand must be moved to make way for a series of concrete settling tanks that will be used in the final stages of sewage treatment.

About 750,000 cubic yards of sand were removed from the site nearly three years ago and deposited on Dockweiler and El Segundo beaches, both of which suffer similar erosion problems. The sand for all of the projects comes from a previously undeveloped knoll just south of the treatment plant on Vista del Mar and has been tested for impurities.

“The beach at Cabrillo is disappearing,” said Dale Hall, a planner with the county Department of Beaches and Harbors, which operates Cabrillo Beach for the city of Los Angeles. “The choice was to take the sand from Hyperion and dump it somewhere, or put it on the beach. This works to everyone’s advantage.”

The Army Corps of Engineers, which has jurisdiction over the federal breakwater abutting Cabrillo Beach, warned in 1987 that the massive wall separating Los Angeles Harbor from the Pacific Ocean could be damaged if erosion at Cabrillo Beach continues unchecked. The corps estimated at that time that the outer beach, which buffers the rocky breakwater from the ocean’s waves, loses 10,000 cubic yards of sand each year.

County officials concurred that a breach in the breakwater was “a distinct possibility” and said winter storms pose a particular threat to a parking lot and road along the breakwater. County officials estimate that winter storms in 1984 and 1985 caused $25,000 in damage to the lot, which had received a $900,000 overhaul after severe winter storms in 1983. The county spent an additional $240,000 on the lot after storms in 1988.

The man-made beach has been locked in a constant struggle with the sea since it was built in 1927. Unlike the inner portion of Cabrillo Beach, which is located inside the breakwater, the outer beach doubles as a recreation area and a fortress, protecting both the breakwater and the harbor behind it.

The beach, which attracted 1.6 million visitors last year, extends 3,000 feet along the outside breakwater from cliffs near Point Fermin. It has no natural source of sand supply and was last replenished in the early 1960s with 1.2 million cubic yards of material dredged from the Los Angeles and Long Beach harbors.

At the time, the beach was about 250 feet wide, but 25 years of waves and storms have whittled away tons of sand, leaving some areas less than 50 feet wide.

The replenishment project is expected to initially widen the beach by about 300 feet and add about 10 acres in surface area. After the sand settles and reaches what officials call “an equilibrium condition,” the beach is expected to be about 250 feet wider and 6.8 acres larger. About 40,000 cubic yards of sand will be deposited in a back-shore dune to provide additional protection against waves and to act as a reserve for emergencies.

The hauling of the sand from Playa del Rey to San Pedro--expected to take three to five months--was originally scheduled to begin next April, but delays at Hyperion and concerns about the spawning of grunion have pushed the start date into September or October. Tentative plans call for the creation of an offshore berm with the first loads of sand to create a temporary beach for the grunion, which slither out of the water every spring and summer to lay their eggs in the sand.

Biologists at the Cabrillo Marine Museum and officials from the state Department of Fish and Game are collecting data on grunion spawning at Cabrillo Beach, which will be used to devise a final plan for distributing the sand, officials said. An environmental report prepared by the county concludes that it will be “impossible to avoid impacts on grunion spawning entirely,” but states the grunion will ultimately benefit from the wider beach.

The city of Los Angeles will pay for the replenishment project, with most of the money coming from the Hyperion construction account. Allan Kawaguchi, an engineer for Hyperion, said officials there agreed to pay a contractor to haul the sand to San Pedro since they would have had to haul it to a landfill anyway. Once the sand is at the beach, the city’s Department of Recreation and Parks will spread it, city officials said.

City officials had no cost estimate for the project, but they described the arrangement as a bargain. The final cost, they said, will depend in large part upon bids received for hauling the sand. In 1987, the Army Corps of Engineers estimated it would cost $1.9 million to replenish the beach with sand dredged offshore.

“It would have cost us a lot more to go out and buy the sand and bring it in,” said Julie Mantrom, an aide to Flores. “By taking advantage of this unusual opportunity, we will be saving a lot of money.”