Except for an area near the Redondo Pier, South Bay beaches received relatively high marks in a recent report card on beachfront water pollution issued by an environmental group. But researchers warn that even in the South Bay, residents should stay away from the water when it's raining.
The report, released this week by Heal the Bay, a nonprofit environmental group dedicated to stopping beach pollution, was based on analysis of water-quality data collected by Los Angeles city and county environmental agencies.
The report graded 49 beach sites from the Ventura County line to Palos Verdes Estates, based on how often and to what extent bacterial levels in the "surf zone" exceeded health standards.
The report's overall conclusion, according to Roger Gorke, author of the Heal the Bay report, is that "Santa Monica Bay is safe to swim in during dry weather if you stay 100 yards away from flowing storm drains and piers. But in wet weather, it's not safe to swim anywhere for three days after the rain has stopped."
The reason wet weather causes high pollution levels along the beaches, Gorke said, is that despite what many people think, the water that passes through storm drains is not treated before it flows into the ocean. During a rainstorm, vast quantities of grass clippings, improperly dumped motor oil, pesticides, animal droppings and other forms of pollutants are swept through the storm drains and into the sea, turning the water near the drainage outlets into a bacterial soup. That heavy runoff can last for three days after a storm.
In dry weather this polluted urban water runoff is much lower, so far fewer contaminants are washed into the ocean. Nevertheless, even in dry weather the water near storm drains can be heavily polluted.
According to the Heal the Bay report card, even in wet weather South Bay beaches generally received far better pollution grades than beaches farther up the coast. The vast majority of beaches between Ventura County and El Segundo received the lowest possible grade--"F"--during wet weather. An F grade means the water exceeded public health standards for three types of bacteria more than 20% of the time, or exceeded acceptable levels for two types of bacteria more than 30% of the time.
From El Segundo south to Palos Verdes Estates, however, only one of the 10 beach sites at which bacterial levels were measured received an F grade in wet weather. That was just north of the Redondo Pier. The other nine beach sites rated Bs, Cs or Ds--not honor roll grades by any means, but still better than most other area beaches.
The South Bay's better water quality during wet weather may result from the fact that the drainage area is less densely populated than drainage areas that deposit their runoff at beaches farther up the coast, Gorke said.
In dry weather, all South Bay beaches received A grades, except an area just south of Redondo Pier, which earned only a C.
"Piers are notoriously bad" in terms of water pollution, Gorke said, even during dry weather. This probably is a result of greater human activity near the piers, he said, activity ranging from restaurants to fishing to homeless people who may not use proper sanitation facilities. Even when wet weather and dry weather grades were combined, an area near the Redondo Pier received a combined grade of F in the report.
Although three of the South Bay sites got better combined "wet-dry" grades this year than last, most of the beach area grades remained the same. Gorke said people can improve water quality at the beaches if they "remember that those holes in the side of the street (storm drain openings) go directly to the ocean without the water being treated."
Consequently, he said, no one should put anything into a storm drain, or allow anything to be washed into a storm drain, that they wouldn't want to swim in later.
Grading the South Bay's Beaches
The following are the 10 South Bay beach locations that were graded in Heal the Bay's second annual summer beach report card, followed by their dry weather grade and wet weather grade:
Location Dry Wet City of Los Angeles Imperial Highway storm drain A D- Opposite Hyperion E. Headworks A C Manhattan Beach 45th Street (extended) A B 6th Street (extended) A B Hermosa Beach South side of Hermosa Pier A C Redondo Beach Redondo Pier (100 yards north) A F Redondo Pier (100 yards south) C C Pearl Street (extended) A D Avenue I (extended) A D Palos Verdes Estates Arroyo Circle (extended) A C