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Artificial Reef Expanded To Mitigate Environmental Impacts Of San Onofre

A mound of rocks slowly builds out an artificial reef off the San Clemente pi...

Photo by Shalina Chatlani

Above: A mound of rocks slowly builds out an artificial reef off the San Clemente pier in this photo taken August 20, 2019.

The Wheeler North Reef off the San Clemente coast is among the largest artificial reefs in the world, and now it’s getting bigger by about 200 acres. The utility Southern California Edison started expanding the reef in recent weeks.

Jenny McGee, restoration project manager at Edison, was aboard a small boat cruising toward a massive barge filled with a mound of rocks.

“We’re building an artificial reef. We’re building a 200-acre expansion to the existing Wheeler North artificial reef that’s already here,” McGee said. “So, when we’re all done we’re going to have 374 acres of artificial reef off the coast of San Clemente.”

Edison started building the Wheeler North Reef in the late 1990s after the California Coastal Commission determined the San Onofre Nuclear Generating Station, SONGS, was harming marine life.

Reported by Shalina Chatlani

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The damage resulted from the cooling of water. In order to cool down the power generators at the plant, which get really hot, SONGS sucked in approximately 2.4 billion gallons of ocean water a day. That was when the plant was fully operational.

The water that would go back into the ocean would be about 19 degrees warmer than the water that had come in. This decades-long process was harmful the San Onofre kelp bed and the marine life there.

“This reef is being built to replace, and then essentially returning those resources that were lost during the operation of the plant,” McGee said.

McGee said the rocks allow kelp to grow, which attract fish and other marine life. Construction of the initial reef ended a decade ago.

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But now Edison is building more because the reef wasn’t meeting some environmental goals, according to Stephen Schroeter, an ecologist at UC Santa Barbara. He’s one of three principal investigators monitoring the reef for the coastal commission.

“The operation of the power plant knocked down the biomass of fish in the San Onofre kelp bed by 28 tons. So there would have been 28 tons more fish if the power plant had not been operating,” Schroeter said.

Schroeter added the current size of the reef isn’t able to bring in that original 28 tons of fish a year, which Edison is required to do.

“The requirement is too great for it to be done in one season. They are going to build part of it this year, and then they are going to complete it next year,” Schroeter said.

The new size of the reef is projected to be around 400 acres. But, Schroeter said the coastal commission won’t be able to gauge the performance of the new reef or its size until it’s been around for a while.

McGee echoes those sentiments. She said Edison has to achieve 28 tons of fish and 150 acres of kelp forest for every operating year of Songs — or 32 years.

“So what that amounts to is 4,800 acres of kelp habitat and 896 tons of fish. So we’ll be counting and measuring for a long time here,” McGee said.

McGee said the $20 million expansion project is being paid for by ratepayers.

Listen to this story by Shalina Chatlani.


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