How Austin is battling algae potentially fatal to dogs

The city will undertake the fourth year of a pilot program to slow the growth of harmful blue-green algae on Lady Bird Lake and, so far, the program has seen mixed results.

Why it matters: A cyanobacteria outbreak on the lake in 2019 killed several dogs.

• Blooms have also occurred on Lake Austin, other Highland Lakes and on Barton Creek, where a dog likely died from toxic algae in 2022 after swimming in "Barking Springs," just downstream from Barton Springs pool.
• The algae is also harmful to humans, who can experience nausea, headache, watery eyes and sore throat if they ingest it.

The big picture: Scientists predict the problem will worsen as Texas' climate grows warmer , heating up lakes and rivers.

How it works: The five-year pilot program involves applying a lanthanum-modified clay in specific areas of the lake, which binds to phosphorus — a key source of nutrients for algae.

• The clay makes the phosphorus unavailable to the algae, hopefully reducing its primary food source and growth.

State of play: Red Bud Isle saw a reduction in the amount of harmful algae after each application in June, while the July and August applications "appear to hold the line without achieving any further reduction of the algae," according to a city news release.

• "By the time the following June and the first application of the year rolls around, the algae has generally returned."

Of note: The pilot program, which is funded through the drainage charge assessed on utility bills, costs $300,000 per year.

Context: Algae and cyanobacteria occur naturally in water, but they're more likely to grow into harmful algae blooms when the water is slow-moving, warm and full of nutrients like nitrogen or phosphorus.

• Harmful algae blooms can look like foam, scum, mats or paint on the surface of the water, according to the federal Centers for Disease Control and Prevention. Blooms that grow underneath the water can be harder to detect.

Between the lines: Reducing the amount of nutrients washed into the lake is likely the most effective solution, officials said.

• Residents should limit the use of fertilizers and pick up after their pets, and more trees, shrubs and native grasses along creeks could help filter pollutants from stormwater.

What's next: The first application will begin today at Red Bud Isle, the boat ramp on the north shore of the lake and the north shore of the lake between I-35 and the lagoon behind the Festival Beach boat ramp.

Be smart: Try looking for spots with cooler waters or even swimming pools — you can reserve private pet-friendly pools through Swimply or head to K9 Water World in San Marcos— for a safe spot for your pooch to doggie paddle.

• Cedar Bark Park in Cedar Park is a 5-acre, fenced dog park with a pond.

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