Faulty septic systems have long been blamed for polluting some of California's most popular beaches. Yet few scientific studies have established a direct link between septic systems and coastal contamination.
Now, in the first study of its kind, Stanford University researchers have tracked a plume of polluted groundwater from a septic system to one of Northern California's top recreational beaches. The researchers say their findings could be an important step toward improving wastewater management in coastal communities throughout the United States.
"The flow of groundwater directly to the ocean is very hard to measure," said Alexandria Boehm, associate professor of civil and environmental engineering at Stanford. "We hope that this work will raise awareness of the importance of groundwater as a source of pollution, and that coastal communities will look at this source when considering conservation efforts."
Since 2008, Boehm and her Stanford colleagues have been studying the flow of groundwater from a large septic system at Stinson Beach, a favorite destination of swimmers and surfers about 20 miles north of San Francisco that's managed by the National Park Service. The study is supported by an Environmental Venture Projects grant from Stanford's Woods Institute for the Environment.
Stinson Beach is relatively clean compared to other California coastal sites, such as Malibu and Rincon Beach, where high levels of bacterial contamination have been blamed on failing septic systems. Efforts in these communities to make the costly switch to sewer-based plumbing have proved contentious.
At Stinson Beach, the Stanford team has worked closely with local and federal agencies to educate the public on the pros and cons of septic systems and develop a consensus on how to improve groundwater quality.
In septic systems, wastewater drains from toilets and sinks into an undergr
|Contact: Mark Shwartz|