Golden Mussel Veligers Detected in Lake Palmdale; PWD Preparing Plan by Palmdale Water District Aug 13, 2025 Member Submitted News PALMDALE – The California Department of Fish and Wildlife (CDFW) has found three golden mussel veligers in plankton samples collected from a dock at Lake Palmdale, which stores Palmdale Water District’s (PWD) water from the California Aqueduct and Littlerock Reservoir. The July 15 confirmation of the golden mussel veligers, which is the larval stage, marks the first of its discovery in a body of water connected to the aqueduct’s East Branch. The invasive mussels have been detected in numerous locations in Northern California and the aqueduct’s West Branch. Although the veligers were collected from a dock close to the aqueduct inlet at Lake Palmdale, the actual source of the mollusk has not been determined. “We are in the process of preparing a monitoring and control plan for handling the golden mussels,” PWD Assistant General Manager Scott Rogers said. “It’s unfortunate they made it to Lake Palmdale, but it’s not a surprise. They’ve been moving south since its discovery last October in the Sacramento-San Joaquin River Delta. “A copper-based algaecide, commercially available as EarthTec, is effective in controlling mollusks,” he added. “We know that other water agencies have used it effectively to control other mollusks.” The Sacramento-San Joaquin River Delta is the heart of the California State Water Project, which moves water from the north to the south via the 444-mile aqueduct. The tiny veligers do not affect the quality of Lake Palmdale’s water, which is treated at the Leslie O. Carter Water Treatment Plant before being distributed to customers. However, they must be controlled because their infestation could clog pipes, pumps and treatment plants. In 2009, the PWD Board of Directors adopted the Policies and Procedures for Boat Access Restrictions at Palmdale Lake, Vessel Inspection, Tamper-proof Tag and Lake Monitoring Program. The Fin & Feather Club, which leases portions of Lake Palmdale for boating and fishing, works cooperatively with the District to have strict inspection rules for boats that are used in the lake under the program. Boaters are required to complete a survey prior to entry, and all boats are subject to inspections. Mollusks, such as the golden mussel, latch onto boats and can be transferred between bodies of water if vessels are not properly washed and cleaned. According to the California Fish and Wildlife Commission, its Invasive Species Program laboratory staff detected the golden mussel veligers from samples that were collected at Lake Palmdale on June 26 and July 10. They were confirmed by cross-polarized light microscopy, polymerase chain reaction and DNA sequencing for species confirmation. Since 1918, the Palmdale Water District has provided high-quality water at a reasonable cost. We pride ourselves on providing great customer care; advocating for local water issues that help our residents; educating the community on water-use efficiency; and leading our region in researching and implementing emerging technologies that increase operational efficiency. For more information about PWD, visit www.palmdalewater.org. ###
