The East Bay Regional Park District closed Lake Temescal and the Temescal Beach due to toxic blooms of blue-green algae and other water-quality issues that occurred in unusual weather conditions. This is the 3rd time in a row that Oakland’s Lake Temescal closes its waters for swimmers.

Lake Temescal will be closed this summer due to a toxic type of algae that grows under abnormal warm weather conditions, but the rest of the areas surrounding the lake remains open to the public.

Lake Temescal closed
Lake Temescal and Temescal Beach were closed due to a strong presence of blue-green algae and other water-quality issues that occurred in unusual weather conditions. Credit:

The East Bae Regional Park has declared on Monday that despite the fact that toxicity levels were cleared in February by the winter rains, the lake is still toxic.

Thanks to their lifeguard program at the Lake, the district’s new analysis showed that the toxicity levels rose and now the lake’s waters are not safe for humans and lethal to dogs.

District declarations say that the current drought could be making the toxicity situation worse. According to the Environmental Protection Agency, warmer temperatures are an obstacle for the process that mixes water. This phenomenon starts a cycle: when water does not mix, algae grow thicker and faster, these algal blooms absorb sunlight and make water even warmer, which promotes more blooms.

Exposure to this type of toxic algae can cause rashes, skin or eye irritation, allergic reactions or gastrointestinal problems. It can be fatal for dogs.

The good news is that the park surroundings remain open for other activities like fishing, picnicking, and hiking.

Oakland’s Lake Temescal in the Oakland hills, near the interchange between state Highways 24 and 13. The park was originally constructed as a storage lake for drinking water and open to the public in 1936, as one of the District’s first three parks.

Last summer, Lake Temescal was not the only on closed for toxic algae. Quarry Lake in Fremont was closed for the same reasons but reopened on June 25. Campers can go to the water and swim, but dogs cannot because the low levels of toxicity that do not affect humans can be dangerous for the 4-legged animals.

Other lakes with low levels of toxicity are Lake Del Valle and the Arroyo, behind Shadow Cliffs, and Lake Anza in Tilden Regional Park, in Berkeley.

The East Bay Regional Park District encourages visitors who wish to enjoy water activities to visit the following lakes, beaches, lagoons, and pools: Cull Canyon in Castro Valley, Contra Loma Lagoon in Antioch, Don Castro in Hayward, and Roberts Pool at Roberts Regional Recreational Area in Oakland.

Other lakes also closed  due to blue-green algae toxicity levels

According to the East Bay Regional Park District website, Lake Chabot and Shinn Pond also present high levels of toxicity due to the blue-green algae that grow in them and humans and dogs are not allowed to swim in those waters.

Source: East Bay Regional Park District