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Clear Waters Don't Clear Watsonville's Pinto Lake of Toxic Algae Problem

Krista Almanzan
Credit Krista Almanzan
Signs at Pinto Lake in Watsonville still warn of the dangers of toxic algae.

Summer has arrived at Watsonville’s Pinto Lake Park. School children are having end of year picnics, and the RV camping spots are filling up.   But what hasn’t arrived are the toxic algal blooms.   

In recent years Pinto Lake has been plagued by chronic blooms of a toxic blue green algae.  It looks bad, smells worse and has the potential to make people sick.

The algae produce a toxin called microcystin that when touched or ingested can cause nausea and even liver failure.  It’s been linked the death of birds, fish and even sea otters in the Monterey Bay.    

Between 2009 and 2012, the microcystin in Pinto Lake was averaging 100 times the California health limit.  But for about a year now, it has not been detected at toxic levels and the water looks clear.

“From the beginning we have tried to educate people about it, and we don’t stop that based on what we see.  So the signs are still posted saying that it’s dangerous,” says Patricia McQuade who runs Pinto Lake Park for the city.

Those signs on the shoreline note you shouldn’t eat fish caught in the lake and swimming is banned.    McQuade also still has anyone who goes out in a boat sign a waiver noting they understand the risks.

“I’d like to say it’s a sign of progress.  I’d like to take credit wherever I can for whatever we’ve done, but this lake has surprised us too many times,” says Robert Ketley, Watsonville Public Works and Utilities. 

He adds, “this problem is far from solved.”  But Ketley is part of a team which includes several agencies who are working on a solution, a task which got easier after the cash strapped city received two grants in 2014.

They’ve since taken a number of steps to address the nutrients in the lake that feed the algae including going after carp.  The bottom feeding fish stir up the lake’s nutrient rich sediment, which helps the algae thrive. 

With an $11,700 grant from the California Coastal Conservancy, they were able to electro-fish a lot of carp over the past year.

“The total was 3,358 pounds of carp removed,” says Jackie McCloud, Watsonville Environmental Projects Manager Jackie McCloud.  “Now were at the final phase where we are looking at the water quality data to see how that removal of carp affected our nutrients.”

They’re also about to embark on another big project.  With a $750,000 grant from the State Water Resources Control Board, they’re planning to do a chemical treatment in the lake that will lock the nutrients into the sediment.

“So that those nutrients are no longer available to the blue-green algae, so we’re effectively starving them of a nutrient source,” says Ketley.

The grant will also help them continue to work with homeowners and farmers in Pinto Lake’s watershed to identify sources of nutrients on their land and keep them from running off into the lake. 

In time Patricia McQuade hopes everything at Pinto will truly be back to normal.  She points to a mama duck and two ducklings at the water’s edge. 

“Normally I’d be gathering the kids around and talking about them.  Now we still for the last two years mostly have been keeping kids hands out of the water. And I want to get back to talking to kids about the nature and not so much the policing,” says McQuade.

You can learn more about the plan for the $750,000 grant at the upcoming meeting of the Friends of Pinto Lake.   Robert Ketley and Jackie McCloud will be talking with the community group.

Friends of Pinto Lake Meeting  

Wednesday, July 8th  (NEW DATE)


Pinto Lake City Park

Community Room

451 Green Valley Road


Krista joined KAZU in 2007. She is an award winning journalist with more than a decade of broadcast experience. Her stories have won regional Edward R. Murrow Awards and honors from the Northern California Radio and Television News Directors Association. Prior to working at KAZU, Krista reported in Sacramento for Capital Public Radio and at television stations in Iowa. Like KAZU listeners, Krista appreciates the in-depth, long form stories that are unique to public radio. She's pleased to continue that tradition in the Monterey Bay Area.
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