Golden mussels have been declared an emergency in Yolo County, but boat inspections for the invasive mollusks are no longer required at Lake Oroville in Butte County. … On April 29, the California Department of Water Resources announced that boat inspections are no longer part of DWR’s mussel prevention program at Lake Oroville. Earlier this month, Yolo County Board of Supervisors declared a state of emergency when the invasive species was found at the Port of West Sacramento. The emergency applies to waterways connected to the Sacramento-San Joaquin Delta. That doesn’t include Lake Oroville, which is formed by the Oroville Dam and impounds the Feather River. DWR decided that Lake Oroville’s deeper waters are too cold for golden mussel larvae.