At the height of summer, folks from Santa Barbara and beyond are flocking to the city’s beaches, and the number of people swimming, surfing and frolicking in the ocean is at its peak.
Under the inviting blue sheen of the sea, however, exist potentially dangerous creatures most don’t think about when heading out into the water — not sharks, but bacteria.
Though potentially harmful bacteria exist in the ocean at all times, the levels fluctuate, meaning some days are better for a dip than others.
That’s where Santa Monica-based Heal the Bay comes in.
Whereas public health officials typically test these levels once a week, with results taking 24 to 48 hours to return, the environmental nonprofit is developing a tool called NowCast that is looking to accurately predict bacteria levels on a daily basis.
The county’s Environmental Health ocean water monitoring program tests 16 beaches between Guadalupe Dunes and Carpinteria State Beach in Santa Barbara County.
NowCasting technology has been around for about a decade, but was only really used in the Great Lakes region, said Ryan Searcy, Heal the Bay’s beach water quality modeler, who has been developing and running its NowCast program.
“There have been other places like Hong Kong and Scotland that have tried it out too, but this is really the first time that NowCasting has been brought to ocean beaches and in California, where most beach visits in the world happen,” Searcy told Noozhawk.
The tool is currently testing summertime levels in five Southern California beaches: Arroyo Burro Beach Park and East Beach in southern Santa Barbara County, the Santa Monica Pier, Belmont Pier in Long Beach and Doheny State Beach in Dana Point.
“What the NowCasting tool tries to do is take lots of different data from different environmental parameters,” Searcy said. “What are the waves doing? What’s the tide doing? Is there a river flowing there? Is it cloudy? Is it raining?”
There are three types of “fecal indicator bacteria” that NowCast and public health officials test for in the water; Their presence, Searcy says, are associated with harmful pathogens beachgoers should avoid.
“There’s total coliforms; fecal coliforms, which is most commonly known as E. coli; and enterococcus,” he said. “And those alone aren’t necessarily dangerous to humans, but they indicate when pathogens are around.”
NowCast uses its results to grade the beaches based on how safe the water is. Heal the Bay has likened using the tool to checking the weather forecast before deciding whether to hit the beach.
NowCast uses a trove of historic water quality data to create a linear-regression model that can be tested to see if it can predict a day’s water quality when that day’s specific parameters are plugged into the model’s equation.
The tool is being developed in partnership with Stanford University and UCLA, and is funded by state Water Resources Control Board grants.
“The first couple phases of the project have been testing out if these models can be made for ocean beaches and if they’re better than the current method of waiting 24 hours or a week for a sample to come back,” Searcy said. “A couple papers have been published, and (the models) have been shown to be accurate and effective.”
“A huge part of our economy is based on visits to the beach,” Searcy said. “Having clean beaches and having good information about them is very important because of that.”
It also better informs policy-makers looking for the most effective ways to address related environmental and health problems, he said.
Santa Barbara’s beaches tend to receive good grades, he said. Santa Monica’s, on the other hand, can expect a bacteria-level “exceedance” once a week, when the level crosses a threshold that’s deemed unsafe.
A number of factors contribute to the number of bacteria in the water, including rain, which washes harmful pathogens from land out to the sea.
Thus, the drought has contributed to Santa Barbara’s above-average ratings by reducing the frequency of showers.
A rainstorm that follows a long dry period, however, makes the levels even higher, as pathogens have had a longer time to accumulate on land.
One reason the waters around the Santa Monica Pier have been so poor is the pier itself, which tends to stifle mixing within the water and makes it harder for bacteria to be washed out to sea.
“Our goal, as written by the grant, is to have 20 to 25 beaches up and running by the end of 2018, with some wintertime beaches,” Searcy said.
Even without up-to-date water-quality information, there are still a few basic rules beachgoers can follow to minimize the risk of getting sick from the ocean: waiting three days after a rainstorm to go swimming; avoiding swimming near storm drain outlets, which also wash bacteria out to sea; and swimming 100 yards or more from piers.
Heal the Bay’s Beach Report Card, a sister water-quality program that grades beaches every Friday, is hosting NowCast, and is available on Apple and Android platforms.
— Noozhawk staff writer Sam Goldman can be reached at sgoldman@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.