Less rain means less urban runoff
The region saw a drop in bacteria-related beach advisories amid a decrease in polluted runoff, data show.
The lack of rain results in fewer pollutants and better water quality at Southland beaches, data show.
California’s recordsetting drought might be making area waters less prone to bacteria, according to government data.
The Environmental Protection Agency monitors the nation’s beaches for various indicators for contamination. In 2015, 762 advisories were issued for San Diego County’s 46 beaches. The majority were because of rainfall pushing runoff into the ocean.
That trend is on the downswing from a peak in 2013, according to an EPA database. In that year, there were nearly double the number of bacteria-related advisories, a number that lessened as the California drought got underway.
A beach advisory is analogous to a weather warning. The water may be unsafe, but swimming and water activities aren’t prohibited. Only when certain conditions are met will a beach close. The type and frequency of the advisories can vary beach by beach.
Beaches have a series of testing locations that send reports to the EPA. The larger the beach, the more EPA testing locations it has.
It is common for advisories to last three days to a week. When the water is dangerous to health, the advisories tend to last much longer.
Rainfall advisories are the most common. According to the nonprofit group Heal the Bay, advisories typically occur after there is at least one-tenth of an inch of rainfall, and often last for three days.
A Heal the Bay study released earlier this year showed that Southern California saw significant improvements in beach water quality because polluted runoff into the Pacific Ocean had reduced, in part because of a lack of rain.
Southern California’s recorded average rainfall was way below normal. Downtown Los Angeles reported 58% of normal rainfall between January and April.
About 97% of Southern California beaches received an A or B grade for water quality during the busy summer months, according to the annual Beach Report Card.
Ocean Beach in San Diego shows the peculiarities of water quality: Even on days when it rained, such as June 30 to July 1, 2015, a beach advisory wasn’t issued because it didn’t rain enough. Rain inland, but not at the coast, could create an advisory.
Officials advise people to avoid beaches for three days following rainfall, regardless of advisories.
The EPA notes that rainfall in an advisory also tends to create higher levels of entero bacteria, which indicate more fecal matter in the water.
Swimming in contaminated water can cause infections and illness. Symptoms include vomiting, fatigue and severe diarrhea.
Meredith Meyers, water quality lab coordinator for San Diego Coastkeeper, said that beach advisories shouldn’t be taken lightly.
The elevated bacteria advisories that last days suggest how extreme contamination is in a given area. Parents should be careful, as children tend to be the most affected by the pathogens.
To help keep the beaches safe, Meyers recommends limiting runoff from all possible sources.
“Limiting runoff in your yard is one of the best things you can do,” Meyers said, “as well as picking up dog poop.”
Marine fecal matter causes many of the advisories at La Jolla Shores. That area is home to many sea lions, which raise their young there.
The sea lion pups remain on the shore while the mothers hunt, so their excrement remains near the shore for several months out of the year.
Cross-border contamination is an even larger threat. The Imperial Beach municipal beach was closed for nearly all of November and December because of elevated bacteria levels.
The San Diego County Chapter of the Surfrider Foundation works to prevent cross-border contamination. The group estimates that the Tijuana Sloughs are closed for more than half of the year.
Earlier this year, a blockage of the Tijuana River became deadly as the stagnant water killed marine life. Imperial Beach Mayor Serge Dedina said that he counted at least 50 dead leopard sharks afterward.
Areas of Mission Bay are also prone to long advisories.
The beach near the Mission Bay Visitor’s Center was under an elevated bacteria advisory for several months in 2015 because of several factors: That part of the bay is so far inland that there is less water circulation than in other parts, and its proximity to the freeway also makes it prone to runoff.
In the Heal the Bay report, Monarch Beach in Dana Point ranked fourth among the top 10 worst-polluted beaches in the state, with Santa Monica Pier, Mother’s Beach in Marina del Rey and Redondo Municipal Pier coming in fifth, sixth and seventh, respectively.