While the majority of Marin beaches received top marks for water quality, one has earned a spot among the 10 worst, according to an annual assessment.
The 35th annual “Beach Report Card” by Heal the Bay grades California beaches based on fecal bacteria levels in the water. For the first time, Chicken Ranch Beach at Channel B, on the west side of Tomales Bay near Inverness, received an F grade because of consistently high bacteria levels during summer and wet weather.
Runoff from nearby drainage systems carries stormwater and shallow groundwater across the beach, posing health risks to visitors, the report said. The beach landed on the “beach bummer” list, ranking fourth among the 10 beaches with the worst water quality in the state.
The report gave 25 of the 29 beaches tested in Marin received either an A or a B grade in the spring and summer of 2024. That’s 86%. The dry summer average is 100%, the report said.
During the wet weather from April through March, 17 sites received A and B grades, and four sites received C and F grades. The five-year wet weather beaches grade average is 82%.
“The latest report shows a clear link between our water quality and rainstorms,” said Arti Kundu, manager of Marin County Environmental Health Services’ water quality monitoring program. “The consistently good grades for summer dry months demonstrate that our coastal beaches remain safe and healthy for recreational use.”
“At the same time, the report’s poor findings on Chicken Ranch Beach at Channel B highlighted the importance of addressing localized efforts to address runoff and stormwater impacts,” Kundu said.
Over the summer, the Tomales Bay Foundation and Marin County Parks began work on a $1.3 million restoration project on the wetlands neighboring the beach and Channel B, an artificial ditch that drains a nearby hillside and flows water close to the beach.
Channel B is contaminated with fecal coliform and E. coli bacteria that were tested as exceeding state limits for recreational water areas, according to a project report. Water tests found that the channel contains nonhuman fecal DNA.
The project involves filling 230 feet of Channel B and redirecting its water through a wide wetland area that includes three shallow pools in order to filter the bacterial contaminants. Plans include having the restored wetland flow Channel B’s water into Third Valley Creek for further dilution.
Craig Richardson, a planner with Marin County Parks, said the project is progressing quickly. He said work to remove non-native vegetation, move earth and develop habitat features has been completed.
“The lower reach of Channel B near the beach has been filled, such that Channel B flow is now directed through the new wetland complex, which is expected to significantly improve water quality,” Richardson said.
Erosion control and site cleanup is expected to continue through October. Crews will then plant nearly 8,000 native plants within the wetland, riparian areas and near Third Valley Creek. The project is expected to continue through the end of the year.
Ashley Eagle-Gibbs, executive director of the Environmental Action Committee of West Marin, said her organization advises the Tomales Bay Foundation on the project.
“This much-needed work will enhance water quality at the beach by restoring the adjacent wetlands to naturally filter contaminated water, a win for both wildlife and beachgoers,” Eagle-Gibbs said. “We’re excited to see how this location’s score changes over time and applaud the Tomales Bay Foundation’s hard work.”
Volunteers and staff at the Environmental Action Committee also contribute to the Beach Report Card, gathering water quality data at Drakes Beach and Drakes Estero.
“This data lets visitors know when it’s safe to recreate in the water, promoting public health and informing the need for action when water quality exceedances occur,” Eagle-Gibbs said. “We also amplify local results by sharing water quality exceedances in West Marin on our social media platforms.”
The report card also showed 55,000 gallons of sewage this past year, with close to 15,000 gallons of that flowing into Marin County waterways. County officials said none of those 25 incidents led to closures in the monitored recreational beaches.
The report also showed that statewide water quality actually improved in 2024, and that is likely linked to a drier year, said Annelisa Moe, associate director of water quality at Heal the Bay.
The state received 357 inches of rain, which is 9% less rainfall than normal. By comparison, Marin County had 24 inches of rain, which is 7% above the historical 10-year average of 22 inches, Moe said.
“This year gives us another snapshot of a year in water quality that really supports the idea that bacterial water quality responds to climate whiplash,” Moe said.
The Beach Report Card is available at bit.ly/3IAjFGa.