PLEASANTON, California — California is investing $7.5 million to slow the spread of invasive golden mussels, committing $6 million in one-time funding and $1.5 million in ongoing annual support to protect the state's waterways and water infrastructure.
Pleasanton, an Alameda County city of roughly 80,000 in the East Bay, relies on State Water Project deliveries tied to the Sacramento-San Joaquin Delta that the mussel threatens.
The golden mussel, a freshwater mollusk native to Southeast Asia, was first detected in North America in the Sacramento-San Joaquin Delta in October 2024. Since then, the species has proliferated statewide, with sightings as far south as San Diego and, most recently, at the Port of West Sacramento. Over the past two months, Sacramento, Kern, and San Joaquin counties have declared local emergencies in response to the invasive species threat.
The mussel's tendency to rapidly reproduce, forming dense colonies on underwater surfaces, can clog pipes, pumps, and critical water infrastructure while disrupting local ecosystems. According to the California Department of Fish and Wildlife, the mollusk attaches itself to watercraft and equipment, "hitchhiking" between water bodies. Its spread into waterways serving State Water Project facilities is of particular concern. Some 30 million Californians rely on the Delta for water, and damaged infrastructure would increase maintenance costs and water rates, said Assemblymember Rhodesia Ransom, D-Tracy.
The 2026-27 state budget funding will establish five Delta-based decontamination sites to inspect boats and equipment for invasive mussels and remove them before they spread to other waterways. Ransom said the relief funding could be released as early as this month pending the governor's sanction.
