By Adam Kaye
North County Times
January 4, 2006
NORTH
COUNTY ---- Powerful waves have stripped the precious sand
from many local beaches, but some coastal experts said Tuesday
that most of it should return in the spring and summer.
From Oceanside Harbor to Del Mar's prized beachfront, the
heaviest surf since 1998 has carved stretches of shoreline
down to the cobble.
The
National Weather Service has posted a high surf advisory
through 2 p.m. Friday, and lifeguards reported breakers of up
to 10 feet on Tuesday.
The scouring winter waves might take sand from the shoreline,
but chances are the granules have accumulated on the ocean
floor within 300 yards of dry land.
"It happens every year," said Bob Guza of the
Scripps Institution of Oceanography in La Jolla. "Beaches
build up in the summer and then erode with the first large
waves of winter, and that's what we've just had in the past
couple of weeks."
Today's erosion is more pronounced than in recent years, he
said, because the surf has been at least moderately large over
the last two weeks.
Guza leads a team of researchers that uses airplanes,
all-terrain vehicles, personal watercraft, buoys and
satellite-based equipment to plot sand movements at beaches in
Torrey Pines and San Onofre. The team's product is called the
Southern California Beach Processes Study.
During the winter, Guza said, sand generally travels offshore
to form sandbars at depths of 15 to 20 feet. Bigger swells,
and the undertow they cause, may push the sand into deeper
water.
"You can get 3 or 4 feet of erosion on the beach,"
he said, "then there will be 3 or 4 feet offshore in some
location where it wasn't before."
The comparatively gentle swells of summer tend to push the
sand from the sandbars back to the shore.
"The question about erosion is, does 100 percent of it
come back or does 92 percent of it come back?" Guza said.
The San Diego County Association of Governments will attempt
to answer that question in March, when it performs its own
survey of beach widths and sand depths at 66 locations in the
county, said Rob Rundle, a staffer with the regional agency.
In 2001, the association coordinated a $17.5 million project
to pump 2 million cubic yards of offshore sand onto 12 beaches
along the county's coastline.
On most beaches today, the fruits of that project are all but
gone. Rundle, however, remained optimistic.
"That cobble beach that's exposed right now might not be
exposed in the spring, but we really won't know until
then," he said.
The scoured beaches and big surf have prompted warnings of
coastal flooding, but city officials and lifeguards have
reported no significant property damage.
Oceanside lifeguards have pulled back some of the bonfire
rings on that city's beaches and are monitoring playground
equipment south of the pier, said Ray Duncan, head lifeguard.
Swift currents have carved a 2-foot-high berm along much of
the beach in Oceanside, he said.
The same erosion is evident in Carlsbad, Encinitas, Solana
Beach and Del Mar.
To prepare for winter, the city of Encinitas builds a tall
berm of sand to protect Moonlight Beach. Sand is deep and
luxurious to the east of the berm and nearly nonexistent to
the west.
The erosion has narrowed the beaches along the entire length
of Encinitas' six miles of shoreline, making access difficult
for lifeguards, Capt. Larry Giles said.
During a rescue last weekend, a lifeguard truck was swamped by
a wave, he said. Beachgoers also can find themselves trapped
at the base of the bluffs.
On Tuesday morning, waves in Del Mar crashed against the
seawall that separates the beach from multimillion-dollar
homes. To the north, the surf pummeled Solana Beach's bluffs.
"There's not a whole lot of sand left," a Solana
Beach lifeguard said, "and the swells just keep lining
up."
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