OAKLAND — Lake Temescal reopened to swimmers over the Labor Day weekend after being closed for 46 days due to an unusually persistent toxic algae bloom.
It took several water treatments with an oxidizer and eventually use of a truck to suck up scum and bring the water quality back to acceptable levels, said Hal MacLean, the East Bay Regional Park District's water management supervisor.
"It was a bad year for swimming at Lake Temescal," MacLean said, "but we plan on being more aggressive in the future, particularly using the truck for removal, if the problem returns."
Reopened on Saturday, the 13-acre lake near highways 24 and 13 had been closed to swimmers since July 18.
Public swimming will be allowed there through October, but lifeguards will not be on duty the rest of the season so visitors are advised to swim at their own risk.
The blue-green algae emitted microcystin, which can cause rashes, vomiting and flu-like symptoms.
MacLean said the drought aggravated the problem this year by reducing water flows to dilute and wash out algae that flowed from Temescal Creek into the lake, part of Temescal Regional Recreation Area.
Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff