Mitigation pilot set to tackle harmful algae in Lady Bird Lake

Most pet owners in Austin recall the fateful summer of 2019, when a spate of dog deaths was traced back to contact with toxic algae in Lady Bird Lake. Since that time the blue-green algae, or cyanobacteria, has been identified in other locations, including Lake Travis.

Instead of going into reactive mode when toxic algae is identified, the Watershed Protection Department is instituting a mitigation pilot project to prevent harmful algal proliferation in Austin’s waterways.

This week City Council will be asked to greenlight a multi-term contract with SePRO Corp. to provide extensive sediment and water quality testing as well as chemical treatment of toxic algae as part of a long-term prevention strategy. The proposed contract would extend for up to five years for about $1.5 million.

In a briefing before the Environmental Commission on June 2, Brent Bellinger, an environmental scientist with the watershed department, outlined a series of events leading up to the 2019 dog fatalities. Chief among them was the proliferation of zebra mussels in the lake, along with flooding that caused unusually heavy sediment that overwhelmed Austin Water’s treatment facilities, forcing city leaders to issue boil-water notices citywide.

“The main driver of toxic cyanobacteria growth globally (is) elevated nutrients,” Bellinger told the commission. “What we saw in 2019 and 2020 was a real significant increase in ammonia concentrations and phosphorous concentrations.”

Going forward, Bellinger advised residents and visitors to exercise vigilance while enjoying Lady Bird Lake. “We’re urging people that if you see algae consider it toxic. Keep your dogs out of the water during the summer and avoid any interaction with the algae.”

Photo made available through a Creative Commons license.

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