Department of Water Resources
A daily compilation of significant news articles and comment
March 9, 2009
4. Water Quality –
Beach receives bounty of dredging
Agua Hedionda Lagoon gets biennial cleansing
The
By Michael Burge
A dredge has been transferring sand this week from the bottom of Agua Hedionda Lagoon onto the beach just south of
Every two years, the power plant's owner, NRG Energy, scoops sand from the lagoon bottom to keep the lagoon from filling up and cutting off the plant's supply of ocean water, said David Lloyd, the plant's director of community relations.
The sand enters the lagoon from the ocean as the power plant sucks seawater in to cool its steam generators.
NRG Energy owns the 400-acre lagoon and has dredged it every two or three years since the plant went into operation in 1954 on the south shore of the waterway. The dredge forces the sand to the beach through a 20-inch-diameter pipe.
Eric Munoz, president of the Agua Hedionda Lagoon Foundation, said few realize that the shimmering lagoon that people see today – with an active fish hatchery, mussel farm, YMCA camp and boating – did not exist before the 1950s. It was a muddy slough that 18th-century Spanish explorers dubbed “agua hedionda” – “stinking water.”
“This is part of a regular cycle of lagoon management and without these regular cycles of dredging, the lagoon would suffer,” Munoz said. “If we did not dredge, we would not have the boating or the diversity of uses.”
Legislation and litigation have targeted the power plant's use of ocean water to cool its generators, saying the process kills and crushes an unacceptable number of fish and small marine organisms.
Lloyd said the plant gets permits from seven different federal, state and local agencies to dredge the sand and deposit it on the beach, including fromthe U.S. Army Corps of Engineers and the California Coastal Commission.
Most of the sand – about 70 percent – is placed south of the lagoon inlet near Tamarack, and the remainder is piped north.
Front-end loaders form a small sand berm on the beach and spread the ocean soup behind it to get the maximum benefit, Lloyd said. Eventually the ocean will suck much of it off the beach into an offshore canyon, he said, and then the dredge is repeated.
“(The beach) is cobbles if it's not replenished,” Lloyd said. “We started in mid-December; it will be completed by April.”
Lloyd said the power plant runs less frequently today than it did in the past, causing the lagoon basin to fill up more quickly.
“It almost closed the lagoon mouth” this year, he said.
The slurry offers a fringe benefit for gulls that pick through the runny goo for worms and other small animals that please their quirky palates.
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