City continues battle against toxic algae, zebra mussels

Despite record high temperatures, crowds are carrying on with Austin summertime traditions, flocking to cool off by Barton Creek and the Colorado River. Brent Bellinger, a reservoir ecologist for the city, stopped by Wednesday’s Environmental Commission meeting to share a brief update on the state of these beloved waterways.

Concern over the safety of Austin’s lakes mounted in 2019 when several dogs died after swimming at Red Bud Isle, a popular Lady Bird Lake destination in West Austin. Since then, the Watershed Protection Department has been closely monitoring neurotoxins produced by stagnant algae proliferating in the city’s waterways.

Red Bud Isle continues to have the greatest number of recorded HAPs, or harmful algal proliferations, though smaller amounts have been detected at Auditorium Shores, Festival Beach, Walsh Boat Landing and Jessica Hollis Park. Still, Bellinger is hopeful that a $300,000 pilot project is showing preliminary signs of mitigating toxic algae overgrowth.

The pilot project, which neutralizes algae-fueling phosphorus molecules with bentonite clay, entered its second phase last week. While last year targeted only Red Bud Isle, this time the compound was also applied near Festival Beach, east of Interstate 35. Following a second treatment in August, 60,000 pounds of the substance will have been introduced to each site.

So far, water samples from Lady Bird Lake have shown a promising 50 percent reduction in phosphorus levels in response to the treatments. But Bellinger maintains that continuing vigilance is key for community members who want to enjoy recreational activities in the lake.

“Pay attention to water flow conditions,” Bellinger said. “The cytotoxins are a new and unfortunate thing to look out for, but you have bacteria, E. coli, swimmer’s itch, all of these things to be aware of when visiting a natural water body. With the right precautions it’s generally not an issue, but it’s important to pay attention.”

Austin’s waterways face another challenge in the form of non-native species, which can significantly disrupt an ecosystem already under stress. Watershed Protection has had its eye on the invasive zebra mussel population since 2017, when years of irresponsible boating procedures erupted in the mollusks’ mass colonization of Lady Bird Lake. In addition to absorbing massive amounts of nutrients, the stubborn invaders have been a headache for Austin’s water utility, which has poured millions of dollars into de-infesting its treatment plants.

Bellinger says the onus for such problems is largely on the state of Texas, which has failed to prioritize ecosystem protections or enforce “clean, drain and dry” campaigns designed to prevent the spread of invasive species.

“The state of Texas has very blatantly shrugged at the whole matter and allowed these species to very easily move through watersheds throughout the state just because there’s not enough enforcement,” Bellinger said. “You go to almost any boat ramp in the upper Midwest and there are cleaning stations and staff everywhere … if you drive out west, they will stop every boat and trailer on the highway and inspect it, with massive fines if you’re transporting these things. The ‘Don’t Tread On Me’ attitude, while great in some ways, can have ecological consequences.”

For up-to-date information on lake conditions, consider bookmarking dashboards. Austin’s Watershed Department also posts frequent updates on Twitter.

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