The city of Austin is treating Lady Bird Lake for algae blooms for the fourth year in a row.

Treatment of portions of the lake will begin Monday and Tuesday, the city announced in a news release. Treatments will also take place in July and August.

Three major areas are being targeted:

• Red Bud Isle.

• The boat ramp on the north shore of Lady Bird Lake, west of Interstate 35.

• The north shore of the lake between I-35 and the lagoon behind the Festival Beach boat ramp.

The second location is new this year and is being targeted to research “unforeseen impacts on aquatic insects.”

Report: Lady Bird Lake, Lake Austin, Lake Travis among lakes with worst toxic algae blooms in U.S.

The city is using lanthanum-modified bentonite, a type of clay material that binds to phosphorus in the water, making it unavailable for algae to feed on. Blue-green algae, also known as cyanobacteria, is toxic to humans and pets. Lanthanum-modified bentonite is safe for humans, but the city warned that boaters should keep their distance from the barge during applications.

Does blue-green algae treatment work?

The treatments are part of a five-year pilot program the city adopted to combat algae blooms on Lady Bird Lake. Results have been mixed.

More: Liberty Hill wastewater plant ordered to lower level of phosphorus discharged into river

From 2021 to 2023, algae growth was reduced at Red Bud Isle. The biggest reductions were in June, and treatments in July and August maintained progress but did not achieve further reductions, according to the city’s release.

Treatment of the region from the north shore to the middle of Lady Bird Lake, between I-35 and the lagoon near the Festival Beach boat ramp, did not see any reduction in algae from 2022 to 2023.

More: Toxic algae found in lakes LBJ and Inks potentially poses danger to people and pets

The city has budgeted about $300,000 per year to treat algae during its five-year program.

Can toxic blue-green algae harm humans?

Toxic algae blooms can put the health of people and their pets at risk, as well as harm aquatic ecosystems, threaten drinking water supplies and stunt local economies.

The algae can be harmful to humans and deadly to pets if ingested, especially by dogs that lick it off their coats after swimming. In 2021, several dogs became sick or died after contact with algae in area waters.

More: Travis County person dies from ameba after swimming in Lake LBJ. Here’s what to know.

Blue-green algae doesn’t always produce toxin but can in the right environment. Typically, blue-green algae will become toxic in nutrient-rich, warm, stagnant water. Austin officials have advised people to treat all algae as if it’s toxic.

This article originally appeared on Austin American-Statesman: Austin to treat toxic blue-green algae on Lady Bird Lake on Monday