Dry spell has kept bacteria low at beaches

California’s unprecedented dry weather helped make water at its beaches this summer the freest of illness-causing bacteria since Heal the Bay began measuring shoreline water quality 18 years ago.

From Memorial Day to Labor Day, fully 92% of the state’s 494 beaches earned grades of A or B on the environmental organization’s annual summer report card, which was released Thursday. The number of A or B beaches was up 10% over last year’s report card.

Heal the Bay officials attributed the improvement primarily to a lack of urban storm runoff, a major source of pollution.

“The best professional judgment is that roughly three-quarters of the improvement had to do with the weather, and the other quarter with clean beach initiative projects,” said Mark Gold, president of the nonprofit organization. “The combination led to the cleanest summer since we started the report card in 1990.”

Los Angeles County, however, once again recorded the worst ocean-quality grades, with 17% of its beaches receiving Fs. On the bright side, beaches on beleaguered Santa Monica Bay fared well, even bettering the state average.

Water at 93% of the bay’s 67 beaches received grades of A or B, a dramatic increase from last year’s 75%. But the beach at Santa Monica Municipal Pier, which got an F, was the bay’s worst, and the second-worst in the state. The bay’s other lowest achievers included Puerco Beach at the Marie Canyon storm outlet in Malibu and Dockweiler State Beach at Ballona Creek.

Water at beaches in Long Beach and at Avalon on Santa Catalina Island also showed “extremely poor” quality, the report said.

“What the report card tells us is that we are accomplishing the job of improving conditions in the surf zone, especially in summer when beaches are the busiest,” said William Rukeyser, a spokesman for the California State Water Control Board, which has funneled $75 million to local governments for coastline water cleanup since 2000. “What it also tells us is that the job is not yet done.”

On the whole, beaches in Southern California counties scored exceedingly well. Ventura County led the pack. All but one of that county’s 54 beaches received an A, and the other a B.

Farther south, 94% of Orange County beaches received good grades, nearly all of them A’s, as did 99% of San Diego County’s.

The report only represented measurements of bacteria in the water, not trash or toxins.

The dry weather prompted a dramatic turnaround in water quality at some of the region’s historically polluted beaches. Doheny Beach in Orange County and Surfrider Beach in Malibu, which consistently have been among the five worst in the state, both received A’s, courtesy of the drought for the most part.

At Doheny, the runoff water that collects in lagoons on the sand after rainfall didn’t extend to the sea. As a result, the five monitoring stations at Doheny, which usually earn straight Fs or a mixture of Fs and Ds, received five A’s.

The role of weather, however, shouldn’t obscure the contributions made by clean seawater projects in other locations, Gold said.

“We saw excellent results where there were runoff diversion projects that capture the polluted water and pump it into sewers,” he said. “Also, a number of small runoff treatment plants contributed. All these bond measures we’ve been passing in recent years are having an effect.”

Mark Pestrella of the L.A. County Department of Public Works said that the primary source of summertime urban runoff tends to be residential and commercial properties. “When it starts it’s not necessarily dirty, but as it travels across the properties and streets it picks up all these pollutants,” he said.

Although the county has upgraded its storm sewer system to better handle the flow, public education about the need to control ocean-bound pollutants also has played a role in the overall reduction, officials said.

Gold noted that Santa Monica Canyon Beach at Chatauqua Boulevard and Pacific Coast Highway typically has earned Fs and Ds on Heal the Bay’s report card. This summer it got an A because the runoff was diverted.

Gold expressed hope that the improvement, at least to the extent human endeavor can affect it, will continue next year. He noted that a runoff treatment plant has recently been completed at the Puerco State Beach site, which should in the future drastically improve the site’s grade.

New water-circulation pro- jects are undergoing shakedown operations at Mother’s Beach in Marina del Rey and Cabrillo Beach in San Pedro. The projects “use a pump to move the water around so it’s not stagnant in these mostly enclosed beaches, like in a sink or a bathtub,” Gold said.

The summer grades for individual beaches are available at www.healthebay.org/brc/.

james.ricci@latimes.com