Invasive Mussels
Public access to Valley Water reservoirs continues to be allowed, provided that resulting recreational activities do not impact the integrity of our water supply.
The threat of invasive mussels infesting local waters is serious; and Valley Water is being proactive by taking action to prevent their introduction. To reduce the threat of infestation, all boats entering Valley Water reservoirs must undergo inspections under a collaborative effort between Valley Water and Santa Clara County Parks.
Boat Inspection Program
Mandatory boat inspections were instituted on May 23, 2008, following the discovery of invasive zebra mussels in San Justo Reservoir in nearby San Benito County in January 2008. In October 2024, golden mussels were discovered in the Sacramento-San Joaquin Delta and O’Neill Forebay in Merced County. This discovery marks the first known occurrence of golden mussels in North America.
The boat inspection program, overseen by Santa Clara County Parks, has the primary goal of safeguarding our waters from invasive zebra, quagga, and golden mussels, ensuring that recreational boating doesn’t compromise the local ecosystem or impact Valley Water’s ability to store water in its reservoirs for supplying drinking water.
Impact
Zebra, quagga, and golden mussels damage native ecosystems and water supply infrastructure. Growing in thick blankets that clog pipes, pumps, valves, water intakes, trash racks and boat engines, these invasive mussels are difficult to remove and eradicate. They attach to boats, aquatic plants, bait buckets and other water-recreation equipment, spreading when these items are moved from infested waters to other water bodies. Their microscopic larvae can be transported in a live well, bilge or bait bucket.
Don’t Spread Invasive Species
Boaters are strongly encouraged to help avoid spreading invasive species by taking the following steps:
- Inspect all exposed surfaces – small mussels feel like sandpaper to the touch.
- Wash the hull of each watercraft thoroughly.
- Remove all plants and animals.
- Drain all water and dry all areas.
- Drain and dry the lower outboard unit.
- Clean and dry all live wells.
- Empty and dry any buckets.
- Dispose of all bait in the trash.
- Wait at least five days and keep watercraft dry between launches into different fresh waters.
More Information
For more information on boating inspections, boating rules, park hours, and launch reservations, contact Santa Clara County Parks at 408-355-2201, or on-line at parks.santaclaracounty.gov/things-do/aquatics/boating-county-parks. Park hours, inspection locations and reservoir access change seasonally.
For more information on golden mussels refer to the California Department of Fish and Wildlife’s (CDFW) webpage: California’s Invaders: Golden Mussel. If you observe this species take clear, close up photos, using some suitable object to show scale/size and immediately report online, email CDFW at [email protected], or call 866-440-9530.
Comments or questions directed to Valley Water can be submitted through our Access Valley Water system.