The East Bay Regional Park District has closed Lake Del Valle in Livermore for swimming due to a bloom of toxic blue-green algae. People and dogs should stay out of the water.
Staff detected the algae Monday afternoon near the boat launch and are sending water samples to a laboratory in Florida for further testing. Preliminary test results showed a toxicity of more than 20 parts per billion, which exceeds the Park District’s safety threshold.
At five miles long, Lake Del Valle is the largest lake in the East Bay Regional Park District. It is owned and by the California Department of Water Resources and is part of the State Water Project. The Park District is currently consulting with the State on the algae condition.
The park, including the marina and campground, remain open. Fishing and boating are safe for visitors, as long as fish are thoroughly rinsed and the guts removed. Boaters should wash their hands after having contact with the water.
Toxic algae can be fatal for dogs. The Park District strongly urges dog owners to keep their dogs away from the lake until further notice. For people, toxic algae can cause skin irritation, diarrhea, vomiting, headaches and other symptoms.
Toxic algae continues to plague other lakes in the District, including Quarry Lakes in Fremont and Lake Chabot in Castro Valley. Toxic blooms have cleared and warning signs have been removed at Lake Temescal in Oakland and Lake Anza in Berkeley, but the lakes remain closed for the season until April 2016.
The East Bay Regional Park District is a system of beautiful public parks and trails in Alameda and Contra Costa counties east of San Francisco Bay, established in 1934. The system comprises 119,000 acres in 65 parks including over 1,250 miles of trails for hiking, biking, horseback riding and nature learning.