Even on a sweltering summer afternoon, a few dozen people still made it out to Red Bud Isle on Lady Bird Lake Tuesday to escape their homes and walk their dogs. But the place—an idyllic 13-acre dog park hidden away in West Austin—has a dark chapter in its recent history.

Exactly one year ago, a dog died after swimming near a mat of what would later turn out to be a toxic algae bloom. Over the course of the next weeks, the neurotoxin-containing species killed several more dogs before the city banned pets from the water.

The ban lasted until November, when the tests run by the city finally showed that the algae bloom had dissipated.

Now, the city, with help from University of Texas molecular biosciences professor Schonna Manning, runs regular tests of water samples from all along the lake in hopes of catching the next bloom as soon as it becomes a problem.

Developing a warning system

By sheer luck, Manning had an existing contract in place with the city of Austin last summer to study algae in Lady Bird Lake, allowing them to draw a connection between the dogs' deaths and the algae bloom quickly.

The teams has created a swift warning system, with a 1-2 day turnaround, so that as soon as toxic algae appears, the city can begin putting up signs warning the public of dangerous areas and ban pets from the water, if necessary.

"We have kind of a gauged warning system from green to red, depending on the appearance of the lake, as well as what we've found both genetically and biochemically," Manning said.

For now, at least, Manning said her team has not noticed anything in Lady Bird Lake to cause alarm. But that can change in as little as a few days.

Visiting the lake

The first major samples of the summer were taken last week and are still being analyzed.

Jonie Mulder, a writer who lives in Tarrytown, brought her dog CJ out to Red Bud Isle Tuesday. She said it was one of the first times in more than a year that she had visited. When reports came out last year about dogs dying after swimming around Red Bud Isle, Mulder said she immediately stopped going, saying it wasn't worth the risk.

Now, however, Mulder said she just hopes her dog stays away from algae mats when she swims, but that there isn't any signage around the isle to warn of any potential danger.

"As soon as they said like it was killing dogs," Mulder said she stopped going. But Mulder said CJ is "squeamish as it is" and would have avoided sludge or large algae flats, anyway.

No signs of harmful algae yet this year

Stephanie Lott, a spokeswoman for the Austin Watershed Protection Department, which works with Manning on studying the algae, told Austonia that, "When we went out last week, we did not see any suspicious looking algae to send to the UT lab."

Regardless of definitive tests on the presence of toxic algae, Manning said the most important thing for anyone letting their dog swim in any body of water, not just Lady Bird Lake, is to trust their eyes and nose.

"If you look at the water and it looks kind of scuzzy, and there is stuff floating on top, that's definitely a warning that, possibly, it's not going to be a healthy place to go in," Manning said. "So trust your eyes and trust your nose. I mean, if it smells bad, if it looks bad, it's likely bad."