Bacteria levels at Los Angeles County coastal waters are dropping in the summer months, Heal the Bay announced Thursday.
The Santa Monica-based nonprofit released its annual beach report card Thursday that shows 82 percent of L.A. beaches earning A or B grades between April and October, a 7-percent improvement over last year.
“That’s good news for L.A. beachgoers at a majority of beach locations,” said Heal the Bay Water Quality Director Kirsten James.
Heal the Bay attributed the improvement to ongoing infrastructure improvements, mainly stormwater diversion systems that keep bacteria-laden runoff from washing into the ocean.
A press conference held to announce the results of the 2011-12 report card took place at the beach in Pacific Palisades, where construction is underway on an $8 million system that will divert runoff from flowing into the waters off Will Rogers Beach and spreading further south into the Santa Monica Bay.
But most of the beaches in Los Angeles, including several in and around Redondo Beach, continue to notch poor grades when rainy months are factored into the scores. During the winter, stormwater diversion systems can't typically capture all of the polluted runoff that gushes into the ocean.
The report grades more than 650 locations from San Diego County to Whatcom County, Wash., in the summer dry weather and more than 300 locations year-round on an A-to-F scale. Beaches are assigned both "dry" and "wet" grades. Dry weather grades, which are calculated for a 12-month period, are based on water quality samples taken during days with no rain and at least three days after a rain event, according to Heal the Bay. Wet weather grades, which are usually lower, come from samples taken during a rain event and the following three days.
In Redondo Beach, the stretch of sand in front of the Herondo Street storm drain received an A grade for summer dry weather, a B for winter dry weather and an F for wet weather. The south side of the Redondo Beach Pier received a B for summer dry weather, but a C for both winter dry and wet weather.
The beach 100 yards south of the pier received a B for summer dry weather and an A for winter dry weather, but an F for wet weather. The beach at Sapphire Street also received an F for wet weather; however, it scored an A for summer dry weather and an A+ for winter dry weather.
The beach north of the Topaz Jetty received A's for both summer and winter dry weather, and a B for wet weather.
Torrance Beach off the Avenue I storm drain received A's for both summer and winter dry weather, and a C for wet weather.
Lower scores represent higher levels of bacteria that Heal the Bay said put surfers and swimmers at risk for stomach flu, ear infections and skin rashes.
"There's always more that can be done," said Beach Report Card Program Manager Mike Grimmer.
All county health departments are required to test beach water quality samples for three types of indicator bacteria at least once a week during the summer season. Heal the Bay compiles the data, analyzes it and assigns the letter grades.
Heal the Bay said one of the reasons Los Angeles County beaches score lower than their neighbors in Orange and Ventura is because their monitoring agencies collect samples directly in front of storm drains and creeks that channel runoff into the ocean. Orange and Ventura counties monitor 25 yards or more away from those sources.
A handful of significantly polluted beaches helped drag down L.A. County’s overall grades, most notably in Malibu. The city claimed four of the 10 spots on the Heal the Bay’s Beach Bummers list, a ranking of the 10 most polluted beaches in the state: Puerco Beach, Dan Blocker, Surfrider and Escondido. Other county sites on the Top 10 list "beach bummers" are Topanga State Beach and the harbor side of Cabrillo Beach in San Pedro.
In total, 11 beaches in Los Angeles County received F grades during the summer, up from last year’s nine.