East Bay Regional Park District Enacts 30-Day Boat Quarantine After Invasive Golden Mussels Found in Lake Del Valle

Recreational boaters and anglers traveling from Danville and the San Ramon Valley to Lake Del Valle face strict new vessel containment rules after wildlife biologists confirmed the presence of invasive golden mussels in the reservoir. As reported on Thursday, October 22, 2026, by The Independent, the discovery has prompted the East Bay Regional Park District and the California Department of Fish and Wildlife to formally classify Lake Del Valle as infested and impose an immediate 30-day quarantine on trailered watercraft.

East Bay Regional Park District Park Operations Unit Manager Seleney Sanchez and California Department of Fish and Wildlife spokesperson Krysten Kellum stated that vessels launching at Lake Del Valle will be banded with tamper-proof seals upon exit and barred from entering other East Bay Regional Park District waterways—including Contra Loma, Shadow Cliffs, and Lake Chabot—until the 30-day drying and quarantine period expires. Non-motorized kayaks, canoes, and stand-up paddleboards must also undergo thorough clean, drain, and dry inspections at the Del Valle Road entrance station before and after entering the water.

Golden mussels were first identified in North America at the Port of Stockton in October 2024 and likely reached Lake Del Valle through South Bay Aqueduct water deliveries pumped from the Sacramento-San Joaquin River Delta. Unlike native freshwater bivalves, golden mussels form dense colonies inside municipal water intake pipes, pumping plants, and outboard boat engines, threatening flood-control infrastructure, agricultural irrigation networks, and aquatic food webs across Contra Costa and Alameda counties.

Park district rangers and county water officials are expanding dockside inspection staffing ahead of the autumn weekend boating schedule and coordinating with state water agencies on long-term containment protocols. Vessel owners in Danville, Alamo, San Ramon, and neighboring communities are advised to verify current watercraft band requirements, launch fees, and decontamination hours on the East Bay Regional Park District website before towing boats down Interstate 680 and Highway 84 to the reservoir.