OAKLAND (CBS SF) -- Two Alameda County lakes that were closed to swimmers because of the presence of blue-green toxins will reopen on Saturday, East Bay Regional Parks District officials said.
Lake Temescal in Oakland has been closed to swimmers since June 26 and Quarry Lakes has been closed since Feb. 8.
"We are thrilled to reopen the lakes," park district spokesman David Mason said in a statement. "We've been working hard to reduce blue-green-algae."
Park district officials asked the Alameda County Environmental Health Department for permission to reopen the lakes because recent water quality tests have shown only a minimal presence of blue-green algae toxins at Lake Temescal and Quarry Lakes and that permission was granted today, Mason said.
"We are optimistic Lake Temescal and Quarry Lakes will stay open the rest of the summer and we'll continue to aggressively work to monitor and maintain water quality," Mason said. "Safety is our top priority," he said.
Park district officials said blue-green algae is a natural organism found in almost all freshwater streams, rivers, and lakes.
But they said it can begin to bloom and, in some cases, release toxins under certain conditions, such as increased nutrients, limited water circulation, increased temperatures, and low water levels.
The park district said recent treatment efforts at Lake Temescal have been part of a pilot program aimed at helping it develop a long-term strategy for addressing blue-green algae throughout the district.
The pilot program includes enhanced monitoring at the lake to gain a better understanding of the conditions, sources of nutrients, and changes in the lake post treatment.
Park district officials said Lake Temescal and Quarry Lakes will be open to swimming from 11 a.m. to 6 p.m. daily until Aug. 18 and weekends and holidays after that.
They said Lake Temescal will be open on weekends and holidays until Sept. 17 and Quarry Lakes will be open on weekends and holidays until September 4.
Both lakes will continue to be open for fishing.
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