OROVILLE, CA – The California Department of Water Resources (DWR) has announced it will stop requiring mandatory boat inspections and decontamination at Lake Oroville, Thermalito Forebay, and Thermalito Afterbay, sparking concerns among local ecologists.
The decision comes despite recent testing showing no confirmed detection of invasive golden mussels in the reservoir.
The Reason Behind The Shift
According to state officials, a recent risk assessment concluded that Lake Oroville faces a lower danger of a severe infestation than previously estimated. Officials cited the lake’s colder deep waters, lower nutrient levels, and unique shoreline conditions as factors that could naturally limit the mussels’ growth.
The inspection program carried a heavy price tag, costing approximately $7.5 million to launch and $6.5 million annually to operate. In contrast, installing UV treatment for pipes at downstream power plants is estimated to cost around $1 million.
Ecologists Warn Of “Epidemic” Risks
Golden mussels were first discovered in North America in the Sacramento-San Joaquin River Delta in October 2024. The invasive species can spread rapidly, clogging critical water systems, damaging dams, and ruining power plants.
Some environmental experts strongly criticize the state’s rollback. Anthony Ricciardi, a biology professor at McGill University, warned that California is facing an “epidemic of golden mussels” and must control key hubs like Oroville to prevent a widespread ecological disaster. If Lake Oroville becomes infested, recreational boats could easily transport the mussels to other uninfected lakes across the region.
New Strategy Shifts Responsibility To Boaters
State officials maintain they are changing tactics rather than abandoning prevention. The new approach shifts the responsibility to boat owners, asking them to manually clean, drain, and dry their vessels after leaving infested waters like the Delta.
DWR stated that if golden mussels are eventually detected at Lake Oroville, they will pivot to inspecting boats as they leave the lake, similar to protocols at Castaic and Pyramid lakes.
Other Northern California Lakes Maintain Strict Rules
While Oroville scales back, neighboring water managers are keeping their guards up. Local authorities for several Northern California reservoirs confirmed they will not be lowering their defenses. Mandatory inspection programs will remain fully active.
