Algae report prompts notice at Santa Rosa lake, coastal lagoon

A Santa Rosa lake and a Sonoma Coast lagoon have experienced harmful algae blooms this summer, according to state water quality regulators, prompting advisories for visitors.

Lake Ralphine in Santa Rosa’s Howarth Park had “unknown and limited algae,” similar in color to the sometimes toxic blue-green algae that can lead authorities to close waterways to safeguard people and pets. It was found near the boat launch and dock area in late July, according to an online map maintained by the State Water Resources Control Board.

The 25-acre lake remains under a cautionary advisory. Lake Ralphine, along with nearby Spring Lake and a pond at the Rincon Valley Community Dog Park also was hit by blue-green algae last year.

In late June, after a swimmer reported becoming ill following a visit to the Salmon Creek Lagoon north of Bodega Bay, Sonoma County posted a caution advisory and conducted lab testing that turned up signs of harmful algae there.

Meanwhile, 10 recent tests along the Russian River from Cloverdale to Monte Rio all have come back without any evidence of harmful algae blooms, according to the county environmental health division.

You can reach Staff Writer Will Schmitt at 707-521-5207 or On Twitter @wsreports.

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