(Photo via City of Watsonville Facebook)
WATSONVILLE — Watsonville City officials have closed the launch ramp and dock at Pinto Lake City Park until further notice, the city announced on its website Wednesday.
The closure occurred after water quality tests showed high levels of cyanobacteria in a layer of scum that has accumulated around the dock, Watsonville Environmental Projects Manager Jackie McCloud said.
The naturally occurring toxic bacteria has plagued the lake for years, causing the city to frequently close it.
Cyanobacteria flourish in the lake thanks to the phosphates running off from agricultural and residential uses, and from erosion of riverbanks.
The bacteria produce toxins that are harmful to people and animals, causing skin rashes, nausea, diarrhea and liver and kidney damage.
In early April, Minnesota-based HAB Aquatic Solutions treated the lake with aluminum hydroxide, a chemical that binds onto the phosphates that feed the algae.
Those efforts have largely been successful, McCloud said.
“Our water samples show that we did indeed bind the nutrients,” she said.
But the treatment has focused on the deeper parts of the lake, and concerns over wildlife in other parts has further restricted the treatment, McCloud said.
It’s likely, she said, that the wind is driving bacteria to the dock, where it is accumulating.
City officials will sample the water again on Monday, McCloud said.
“We hope that the scum layer dissipates on its own,” she said. “We’re going to let nature take its own course. This is going to be a long-term solution, and we have to keep working on it.”
For information, call 768-3170.
