Photo by Tony Kukulich

Algae blooms are seen here in the water near Windward Point in Discovery Bay. The area has received a danger advisory from the county following toxicity tests late last month. 

If you live in Discovery Bay or the surrounding Delta area, harmful algae blooms (HAB) are a well-known and unwelcome presence each summer, but several local organizations are hard at work, actively searching for a solution to the pernicious water weeds.

Barbara Barrigan-Parrilla, executive director of Restore the Delta (RTD) — an organization that serves as a watchdog agency in defense of the Delta — said two things need to happen before control of the algal blooms can be obtained.

“We have to do the kind of outreach we are doing through the youth program, so we can track in real time what is happening, so that we can get to solutions,” she said. “And then we also have to advocate for solutions through other projects that we do to complement the science, like youth journalism, youth performance and advocating for good water policies.”

Currently, RTD is accepting registrations for its fifth annual H2O Hackathon, an event centered around building an app capable of tracking algal blooms and uploading data through a smartphone to the State Water Board. RTD partners with the San Francisco Estuary Institute and the State Water Board for this event, which has already drawn over 150 applicants from middle school to college.

HAB have been a hotly debated topic in Discovery Bay each summer for the past five years. While fast-water areas where boaters and water-skiers congregate aren’t affected, residents who enjoy a swim off their dock will have to check their water for the trademark green, white or brown foam or scum indicative of algae blooms before jumping in. When the algae bloom, they release toxins, and the scum can float on top of the water or suspend in the water.

Karen Mann, president of the Save the California Delta Alliance (STCDA), said her organization is mainly focused on preventing the tunnel project sponsored by the state government and southern California but is cognizant of the algae and its harmful effects.

“We are concerned,” she said. “There is spraying going on and some people are really opposed to the spray, and we’re really not sure what the health aspects are regarding the spraying ... On the other hand, we can’t have our waterways clogged up with these (blooms). Part of that is the lack of water flow ... The tunnels would affect the waterflow negatively.”

Mann further noted that the coming summer months are the most challenging time, when warm, nutrient-rich, standing water produces the unsightly scum characteristic of the cyanobacteria toxins.

“But it’s not just Discovery Bay,” Mann added. “This phenomenon is happening wherever there is stagnation of water. We know that if the tunnel comes, it’s going to be worse.”

Another local agency seeking a solution to the blooms is the Discovery Bay Community Foundation (DBCF). Each month, DBCF president Jim Mattison takes a team of scientists from state and county agencies out on the Delta to collect water samples from the town’s bays. Results from the team’s most recent trip, on Wednesday, Feb. 19, were not available at press time. But Mattison did have some encouraging information.

“Good news is we have an $80,000 grant that was approved for a load study for Discovery Bay,” he said.

The money will be provided by the United States Environmental Protection Agency, which gives funds to local water boards for distribution to selected projects. The goal of this study is to pinpoint where the surplus of nutrients in Discovery Bay waters is coming from, since excess nutrients feed the HAB and are a major factor in their blooming.

With all these groups working toward the single goal of understanding and controlling HAB, the hope is the toxins can be reduced, if not eradicated. One entity not involved is the Town of Discovery Bay, which has neither the authority nor funding to expend on water safety or quality. Mike Davies, Town of Discovery Bay general manager, said he and his staff will fully cooperate with the county to keep residents safe and informed.

“The town appreciates any and all efforts that are directed at eradicating the presence of harmful blue-green algae from our waterways,” Davies said. “Updates from (the county environmental health division) will be posted on the town website to keep our residents informed.”

Barrigan-Parrilla is encouraged by the efforts being put toward the goal of cleaner, safer Delta waters. She said RTD will continue wrangling with the state and local water control boards to publish information and protect the Delta.

“I’m really trying to build a force for the future, so that we have people ready to build into their lives protecting the estuary as part of who they are,” she said.

Another project Barrigan-Parrilla is developing will bring eight high school and college students closer to the Delta and a solution to the toxic algae blooms. Still unnamed, it will be a student science program that will shepherd students as they investigate and track what happens in the waters of the Delta.

“If this takes me a year to get up and running, then my plan is to go replicate it in other parts of the Delta,” Barrigan-Parrilla said. “This year is the prototype, then we will take it to other parts of the Delta and teach groups throughout the Delta how to do the same thing.”

Participants in the program will upload their results to the Regional Water Quality Control Board as part of the ongoing collaborative conversation about HAB.

For more information on Restore the Delta, or to donate to its upcoming student science program, visit, or call 209-475-9550.

For more information on the H2O Hackathon or to register, visit

For information on the county’s samples from Feb. 19 or to learn more about HAB, visit the Contra Costa Environmental Health page at To see information posted by the town of Discovery Bay, visit