Jun 22, 2018   SOURCE: BusinessWire

Diamond Valley Lake Closed to Recreation Because of Large Blue-Green Algae Bloom Covering Lake, Producing Cyanotoxins

Recreational activities at Diamond Valley Lake have been temporarily suspended by the Metropolitan Water District of Southern California because of a bloom of cyanobacteria—also known as blue-green algae—covering the lake.

All recreational activities, including boating, fishing and hiking, have been suspended at the lake near Hemet in southwest Riverside County until further notice.

Metropolitan water quality experts, however, assured the public that the quality of the district’s treated drinking water has not been affected.

“This is a recreation issue, not a drinking water issue,” said Dr. Mic Stewart, Metropolitan’s water quality manager.

“We don’t want folks coming into contact with or fishing in this water,” Stewart said. “We are not using DVL as a drinking water source right now. Even if we did, our processes for withdrawing the water from the lake and treating it will ensure its safety.”

The algae bloom—one the largest ever seen at the lake since it opened to the public for recreation in October 2003—is caused by naturally occurring organisms that have produced large areas of green water and mats of green scum floating on the lake. Blue-green algae blooms are common this time of year because of the warm weather. The bloom is releasing cyanotoxins, which in high concentrations can be harmful to humans and animals, especially when ingested.

Recreational activities at the lake could be suspended for a week or longer, officials said. Metropolitan continues to monitor the blue-green algae bloom and test cyanotoxin levels and will lift the suspension when conditions improve.

The Metropolitan Water District of Southern California is a state-established cooperative of 26 cities and water agencies serving nearly 19 million people in six counties. The district imports water from the Colorado River and Northern California to supplement local supplies, and helps its members to develop increased water conservation, recycling, storage and other resource-management programs.