AUSTIN (KXAN) — Monday afternoon the City of Austin will start applying a treatment to Lady Bird Lake in an effort to slow down the growth of toxic algae.

This is the third year in a row that Austin’s Watershed Protection Department will apply the treatment to combat blue-green algae on the lake.

It’s part of a pilot program the city started after several dogs died in 2019 after coming in contact with the slimy substance at Red Bud Isle.

Brent Bellinger is a supervisor with the Austin Watershed Protection Department. He says it’s time to treat the algae near Red Bud Isle once again.

“This has been our most toxic spot with very high visibility,” Bellinger explained.

This week, he’ll be working with a water treatment task force from EutroPHIX, specialized in detecting and treating harmful algal blooms.

“We’re going to do a maintenance treatment around Red Bud Isle,” Bellinger said. “Then we’re going to head back down river to hit that section between I-35 and the Festival Boat Ramp.”

Scott Shuler is the national manager at EutroPHIX. He says they’re not eliminating the algae. Instead, they’re simply cutting off its nutrients.

The water treatment task force aims to apply over 35,000 pounds of lanthanum-modified clay to Lady Bird Lake.

“By mitigating that phosphorus, we can reduce or eliminate the amount of toxic algae that grows,” Shuler said. “Over the last couple of years, that’s been very successful.”

The city says the gray substance is safe for humans and animals. It’ll be applied from a barge and sprayed onto the lake.

Initially, it will cloud the water but within a few hours the gray spray will settle to the bottom.

“If we can change the nutrient dynamics out on the water, hopefully we can reduce the overall toxicity we see out there,” Bellinger said.

The first application will take place Monday at Red Bud Isle and then east of I-35 on Tuesday, weather permitting. The city staff says if additional time is needed, the work will extend into Wednesday.

The total cost for treatments, testing and lab work with cost the City of Austin around $300,000.