An Adult Golden Mussel Detected at Teerink Wheeler Ridge Pumping Plant
On July 7, 2025, Department of Water Resources staff found a single golden mussel attached to an intake stop log at John R Teerink Wheeler Ridge Pumping Plant. This pumping plant is located on the California Aqueduct near Mettler and it is the southernmost detection to date of an adult golden mussel in California. Water from the California Aqueduct flows south of here and splits into the East and West Branches of the Aqueduct. Water in the Western Branch of the Aqueduct flows into Quail Lake, where golden mussel veligers were detected in May and June 2025. Water from Quail Lake is released via the Lower Quail Canal, passes through the Warne Powerplant, and flows to Pyramid Lake. Water from Pyramid Lake flows into Elderberry Forebay, and Castaic Lake, which is the terminus of the West Branch. Water from Castaic Lake flows into Castaic Lagoon, Castaic Creek, and the Santa Clara River. Pyramid Lake also releases water to Middle Piru Creek which flows to Lake Piru, Lower Piru Creek, and Santa Clara River. Quagga mussels have been detected in Pyramid Lake and downstream waters.
Water in the East Branch of the Aqueduct flows into Silverwood Lake and Lake Perris. Lake Perris is the terminus of the East Branch.
In response to the detection of golden mussel in California waterways, the state of California has developed a comprehensive Golden Mussel Response Framework (PDF) to address this invasive species threat. DWR, in coordination with partner agencies, has implemented regular inspections and maintenance at State Water Project facilities to minimize the effects of golden mussels. The discovery of golden mussels poses no imminent impacts to water quality or DWR’s ability to deliver water to 27 million Californians.& DWR continues to work diligently to implement protective measures to minimize the spread of this invasive species, prevent the fouling of equipment, and maintain operational capacity.
For specific questions about DWR’s response, please contact Maggie Macias, DWR Information Officer at (916) 902-7405. For questions regarding CDFW’s response, please contact CDFW’s hotline at (866) 440-9530.