Lake Temescal in Oakland Closed Because of Toxic Algae Bloom

For the second summer in a row, Oakland's Lake Temescal will be closed to swimmers indefinitely because of toxic green blue algae, likely exacerbated by California's drought, though the rest of the park remains open.

The East Bay Regional Park District closed the popular lake on June 30 and has no set time for reopening.

Park rangers plan to treat the algae with Pak 27, an oxidizing agent, next week, the district said in a news release.

Last summer, Lake Temescal was closed for more than two months because of a toxic algae bloom. Each summer, the park district runs a lifeguard camp at the lake. Because the children can't go in the water, campers play on the sand, do land-based activities and get wet in sprinklers during the day.

In addition, Quarry Lakes in Fremont is also closed due to an algae bloom. Lake Chabot in Castro Valley and Shinn Pond in Fremont also contain toxic algae, and dogs should not swim in the water, because the algae can kill them.

It's common for toxic algae blooms to break out in warm weather, but the park district said the drought is likely making the situation worse. Warmer temperatures prevent water from mixing, allowing algae to grow thicker and faster, according to the Environmental Protection Agency. Also, warmer water is easier for small organisms to move through and allows algae to float to the surface faster. And algal blooms absorb sunlight, making water even warmer and promote more blooms.

There are lakes and lagoons within the district that are not affected by the toxic algae. Those include: Lake Anza at Tilden Regional Park in Berkeley, Cull Canyon in Castro Valley, Contra Loma Lagoon in Antioch, Don Castro in Hayward, Del Valle Recreation Area in Livermore, and Roberts Pool at Roberts Regional Recreation Area in Oakland.