Austin Watershed taking another step to reduce harmful algae

Second round of harmful algae treatment

Austin Watershed is set to apply a second round of clay material treatment to help reduce harmful and toxic algae in Lady Bird Lake and waters around Austin.

AUSTIN, Texas - Austin Watershed is getting ready to apply a second round of treatment to reduce harmful algae in Lady Bird Lake.

On Monday and Tuesday, they will apply clay material in Red Bud Isle and east of I-35. The material, lanthanum-modified bentonite, reduces the amount of phosphorus that serves as a key food source for harmful algae.

The city says they've seen fewer algae in those two areas after the first application in early June. There is still some algae, so residents are advised to continue to be cautious. Residents should also make sure to rinse themselves and their pets off if they touch the water.

Despite city program, blue-green algae persists

The City of Austin is on year three of its pilot program to reduce the growth of harmful algae in specific areas of Lady Bird Lake.

"I haven't really noticed it too bad unless I come in the morning," Cade Mellon, who was at the lake, said.

"We're not treating algae per se. We're going after, you know, probably the most important nutrient that's out here, which is phosphorous. They need a lot of phosphorus to grow to achieve this biomass and then to start producing the toxins," Brent Bellinger, conservation program supervisor with the Watershed Protection Department said.

Experts say there have been harmful algae blooms on Lady Bird Lake every year since 2019, when it sickened and killed several dogs.

Toxic algae returns to Austin this summer

Experts are noticing an outbreak of toxic cyanobacteria, or blue-green algae, in Central Texas as summer temperatures heat up.

The treatment is part of a five-year pilot program to bring down phosphorus levels.

In past years, there have been mixed results, with a decrease in phosphorus at Red Bud Isle but not east of I-35.

"It seems like it's getting a little better for sure, like overtime, past couple months, seems better, but obviously a concern with the dog, he doesn't really go in the water much, so kind of lucked out there, so I'm able to come here regardless," Dylan Roesch, who was at the lake, said.

Potentially toxic blue-green algae back in Austin

As weather heats up, so does the risk of toxic algae, and the City of Austin says it's back at Lady Bird Lake and Lake Austin.

If you're going to be at the lake when the city's doing the treatment, keep your distance. The barge will spray gray material into the lake that will make the water cloudy for a bit.

Austin Watershed says the treatment is safe for humans, the environment, and wildlife.