Colder Weather Rids Austin Lake Of Toxic Algae

AUSTIN, TX — The onset of colder weather has killed off harmful algae at area waterways blamed for the deaths of residents' pets last summer, officials said Tuesday.

Watershed Protection staff said in an advisory they are no longer detecting harmful algae in Lady Bird Lake. With cool temperatures, harmful algae are unlikely to return until next summer, officials added.

Although there is always some level of risk in a natural water body, officials added, currently the risk at Lady Bird Lake is low. This year, Watershed Protection officials first detected toxins in algae samples taken from Lady Bird Lake on July 14, and continued to find toxins until mid-November. The last positive algae sample was taken on November 10.

Previous coverage:

• Dogs' Deaths Led To Animal Ban At Lady Bird Lake In Austin
• Officials Find More Deadly Algae In Austin Waterways
  
• Toxins Detected In Algae At Lady Bird Lake
  
• Red Bud Isle Reopens After Toxic Algae Scare
  
• Austin Woman Describes Dog's Death At Algae-Infested Lake

"Thankfully, we did not receive any reports of dogs becoming ill or dying due to algae exposure after swimming in the lake this year," officials wrote. "We credit this success to the care dog owners took in following recommendations and keeping their pets out of the water during the long, hot summer and fall."

Reports emerged of dogs dying after swimming in Lady Bird Lake in August 2019. As a resulte, officials this year instituted a weekly monitoring program for harmful algae beginning in late June to help avoid a similar outcome. Additionally, signs were posted at the lake to educate dog owners, and data from the monitoring program has been available on a dashboard at a City of Austin website.

During the low-risk season, officials said they will not be updating the dashboard except to present average temperature and flow data from the summer and fall. The type of harmful algae on Lady Bird Lake is different from the more common algae outbreaks in the Great Lakes and along the Gulf Coast, officials noted.

Rather than being dispersed throughout the water body, the algae grows in clumps at the bottom of the lake bed and rises to surface of the water. There is less information or research available about this type of harmful algae bloom. "Data from the monitoring program this year will help us understand more about when the algae is likely to emerge next year," officials said.

For more information, visit the city's Algae portal.