SAN CLEMENTE, Calif. — Like an underwater
field of dreams, they built it and the kelp came.
A team of Southern California research biologists last week released their draft
report on the success of an experimental test reef built to make amends for the
death of giant kelp forests caused by the San Onofre Nuclear Generating Station.
Kelp is the undersea habitat that provides shelter for a rainbow of aquatic
plant and animal life.
The report, which will be presented to the public Wednesday, concludes that 56
underwater test reefs built by plant owner Southern California Edison readily
served as the launch pad for kelp forests. In turn, those kelp forests attracted
tons of fish and other bottom-dwelling invertebrates, such as the spiny brittle
stars that sometimes can be found in North County tide pools.
Dan Reed, a research biologist at the University of California Santa Barbara,
said Monday that five years of intensely monitoring the experimental reefs built
off the coast of San Clemente just a few miles north of San Onofre's twin
reactor domes, reassured him that kelp could be restored.
"I think there's a lot of reason to be hopeful that the detrimental effects
that the power plant has on the kelp bed at San Onofre can be offset by building
the artificial reef off of San Clemente," Reed said.
Wednesday's public workshop will be held from 12:30 to 5 p.m. at the San
Clemente Community Center, 100 N. Calle Seville, San Clemente. The workshop,
which will allow people to ask questions of experts in attendance, is designed
simply to present information on the results of a five-year artificial reef
monitoring study. It is not a public hearing and no regulatory decisions will be
made.
The artificial reef is designed to compensate for the side effects of San
Onofre's unquenchable thirst for salt water.
According to Edison, the plant sucks nearly 2.5 billion gallons of salt water
from the Pacific Ocean every day. The water is used to cool the plant's innards
before being pumped back into the ocean. However, when that water is released
back into the briny blue, it kicks up a murky plume of sand and other murky
material. Reed said studies performed in the 1980s showed that cloudy water
means less sunlight reaches kelp. Without enough sunlight, young kelp does not
grow.
"It's really affecting the birth rates of new plants rather than killing
the mature plants," Reed explained.
In 1991, the California Coastal Commission ordered Edison to build an artificial
reef to pay Mother Nature back for the one that its nuclear plant's liquid
exhale took away.
After nearly a decade of wrangling, the Coastal Commission decided that Edison
should build 150 acres of artificial reefs to replace what was lost at San
Onofre. However, before building the large reef, Edison decided to build several
small experimental reefs first. Scientists wanted to explore what kind of
materials the artificial reef would best be made from.
So, in 1999, Edison sank 56 piles of boulders and concrete. The piles had
different densities and different mixtures of concrete and stone. Some covered
more of the sea floor than others. After the piles were in place, a team of
divers routinely visited them for five years, recording changes as they
happened.
"They pretty much used up all the graduate student divers in all of
Southern California for the last five years monitoring that project," said
David Kay, manager of Edison's environmental mitigation program.
According to the report, divers watched kelp take hold quickly in most of the
piles after spores drifted over from the adjacent San Mateo kelp bed. The report
notes that all artificial reefs exceeded their performance standards,
maintaining at least four mature kelp plants since 2001. Likewise, divers found
that fish and invertebrates also moved into the new kelp stands at a rate that
paralleled natural kelp forests like San Mateo to the south.
While artificial reefs have become somewhat common in the world's oceans, Kay
and Reed both said it is rare to do a five-year scientific study before building
one.
Reed noted that there were few large ocean storms or other disruptive events
from 2000 to 2005, so the survey does not necessarily say how well the
artificial reefs will hold up to the roughest stuff that nature can throw at the
man-made reefs.
"Five years is a decent amount of time, but it's not enough to capture the
entire picture of what really happens out there," Reed said.
The report also notes that divers began spotting "high densities" of
an ocean sea fan plant called muricea on all of the reefs in 2002 and 2003. Reed
said that if the sea fans continue to propagate, they could eventually crowd out
the kelp.
"It still remains to be seen whether that will be much of a problem,"
he said.
The report concludes that it may be necessary for Edison to hire divers to
periodically kill the sea fans if they get too dense.
Kay, Edison's project manager, said a healthy kelp bed needs a good whack from
the ocean every now and then. When rough weather and or marine animals tear
through the kelp forest, he said they often also remove some build-up of animals
and plants that can crowd out kelp.
"The only way to assure that kelp continues to get a foothold is to scrape
everything off periodically and nature does that with natural kelp beds,"
Kay said.
It will be the California Coastal Commission that decides exactly how much rock
should be placed on the sea floor to create the artificial reefs. Kay said
Edison will probably ask for a more sparse load of rock initially to ensure that
the reef does not become impervious to natural forces that help renew the kelp
forest.
"It's easier to add material than take it away," he said.
However, Reed said the total amount of reef rock to be used for the 150-acre
reef has not yet been discussed between the contract scientists from UC Santa
Barbara and Edison's own scientists.
"I guess the discussion needs to become, what's a reasonable starting
point," Reed said.
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http://www.nctimes.com.
Source: Knight Ridder/Tribune Business News