Winter wallop: Erosion takes toll on L.A. County beaches
Over time, erosion has dramatically diminished areas of Zuma Beach that are frequented by sunbathers and surfers.
It might be hard to remember now, after months of record-breaking rain, but last year at this time Los Angeles County was feeling a bit left out. What had been pegged as a monster El Niño pounded Northern California with rain but sidestepped the Southland—or so it appeared.
Now it turns out that even though the El Niño of 2015-16 did not reach “Godzilla” proportions on the local rainfall charts, it battered L.A. County’s coastline in ways that may take years to repair.
That El Niño–deemed among the most potent along the U.S. West Coast in 35 years–spawned storms over the North Pacific that fizzled before reaching Southern California. But it generated giant waves that bashed county beaches and swept untold volumes of sand from the shoreline into the sea.
Those waves, some of the largest ever recorded, reflected what scientists at the U.S. Geological Survey are calling one of the most powerful climate events in almost 150 years.
And this year’s heavy rains have posed a different, but no less dangerous problem, by flushing garbage from streets into the ocean, where the waves push onto county beaches.
“That’s the worst effect,” said engineer John Kelly, deputy director of the Los Angeles County Department of Beaches and Harbors, “because of the water quality issue. But we’re prepared; we know what to do. We have to get out there and clean things up and get these beaches ready for the public, because they have high expectations.”
BEFORE AND AFTER: Large swells generated by powerful off-shore storms have washed away a road at Nicholas Canyon County Beach.
As for last year’s El Niño, “we got only about 3 inches of rain, almost a record low,” Kelly said. But storms hundreds of miles away distributed waves that hit our beaches hard.
“We didn’t get the storm surge, but we got strong waves driven by high winds, kind of like tsunamis,” Kelly said. “The strength of those waves and the type of erosion they left, that’s something you don’t see every year or even every few years, maybe more like once a decade.”
And the lack of rain accelerated the erosion, because dry coastal rivers couldn’t produce enough sand to help fill in what beaches had lost.
Still, Los Angeles County fared better than it could have, in part because some of its most popular beaches are bolstered by what experts call “artificial beach nourishment.”
“A lot of our beaches—from Santa Monica down through the South Bay–are basically man-made,” Kelly explained. “When the Hyperion Sewage Treatment Plant was built decades ago on sand dunes [near Dockweiler Beach], tens of millions of cubic yards of sand were removed in the excavation and distributed to nearby beaches to make them wider.
“That gave them room to erode in the winter and slowly return in the summer when waves are lower and spaced far apart,” he said. “In a typical cycle, they’re rockier and narrower in winter and in summer the beaches get restored.”
But last year’s El Niño was so damaging that beaches didn’t return to normal during the summer respite. Northern beaches, from Malibu to Ventura County, were particularly hard hit.
“In the Malibu area, they are more natural,” Kelly said. “They were never nourished with other sources of sand. In some areas there, the bluffs have eroded, cutting off access to parking areas and roads.
“If you’re familiar with certain beaches, you’ll certainly notice a difference,” said Kelly, citing Nicholas Canyon in Malibu, where facilities are gone and the walk to the beach is longer than before.
BEFORE AND AFTER: The shrinking shoreline has forced L.A. County's Department of Beaches and Harbors to construct protective sand berms.
County workers try to protect vulnerable beaches each year by erecting 15-foot tall mountains of sand parallel to the shoreline, to block big waves and keep strong rains from damaging buildings and blocking public access.
“We’ve been doing that since 1983, when El Nino took out facilities that cost us many millions of dollars to replace,” Kelly said. “Zuma, Surfrider, Venice, Dockweiler, Hermosa…We know the most vulnerable beaches.
“But there’s nothing we can do to control erosion, but just kind of cross your fingers. In L.A. there’s nowhere to move the facilities back if the shoreline recedes.”
Now Kelly’s department is busy repairing the damage inflicted on a walkway near Malibu’s Carbon Beach. The so-called “Zonker Harris” access road had to be closed after high tides knocked out a portion of the ramp already damaged by years of gradual erosion.
That left only one public route to the pristine strip of sand also known as Billionaire’s Beach. “The ramp was destroyed, and we’re beginning construction to rebuild it,” Kelly said. They plan to replace the 200-foot ramp with a steep stairway that should be more difficult to dislodge.
Whether rebuilding or cleaning up, the department knows that millions of beachgoers are depending on its efforts.
“Our duty is to protect public access to the beach, the parking lots, the restrooms, the concession stands. So that people who can’t afford to live on the beach can still enjoy the beach,” Kelly said. “That’s why this is important.”
BEFORE AND AFTER: Erosion has dramatically transformed entry points to beaches, such as the Escondido Accessway in Malibu.