California water officials to dye Stockton waterfront to study dangerous algae

California water officials plan to dye McLeod Lake in downtown Stockton starting Monday to study the cause of the waterfront’s notorious harmful algae , a city news release said.

Through Friday, crews plan to use a Port of Stockton boat to apply the dye and gather data between Weber Point and Interstate 5, the release stated .

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Depending on conditions, the lake may turn a pink or purplish color from the harmless rhodamine dye, it stated.

The California Department of Water Resources aims to find the cause of harmful algae blooms by using the dye to observe water flows in the lake and San Joaquin River.

Outbreaks of microcystis − or “blue-green algae” − have erupted several times in area waterways in the past decade, The Record reported.

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The blooms are dangerous for both humans and animals, potentially causing cancer and other illnesses. Residents should stay out of the water when scum, or a green or blue-green tint to the water, are present.

Other signs of harmful algae in general include “colors ... mats, foam or paint-like streaks in the water or clumps on the shore,” according to San Joaquin County environmental health officials .

Water officials expect this week’s study of McLeod Lake to end Friday, the city release said. The city plans to schedule another study for early 2025, the release stated.

You can read more about symptoms of exposure to harmful algae, and what to do if exposed, at sjgov.org/department/envhealth/water-quality .

This article originally appeared on The Record: California water officials to dye Stockton waterfront to study dangerous algae