Fighting zebra mussels to be costly

Zebra mussels, the tiny mollusks that have infested lakes from the Great Lakes to Lake Travis, have now proliferated in Lake Austin. “They’re on the docks and on the piers in the millions, maybe the billions,” according to Greg Meszaros, director of Austin Water.

The invasive species, a native of the former Soviet Union, was first discovered in the Great Lakes in 1988. Scientists believe the mussels were carried to the United States via ballast water from large ships. At this point, no one has figured out how to stop zebra mussels, which continue to spread throughout the country, wreaking havoc on native species.

Meszaros told members of the Austin Water Oversight Committee on Thursday that while the Lower Colorado River Authority could kill millions of the invaders by lowering the level of the lake, the city is going to have to take a hard look at what might happen before requesting that LCRA take that action. In years past, LCRA has lowered the lake every two to three years to allow residents to more easily clean their piers and docks.

Council Member Alison Alter, who represents the area around Lake Austin, seemed concerned to hear that the lake lowering might not be happening soon. However, she told Meszaros that such a conversation was probably not within the purview of the committee. She asked him to work with her office to facilitate a meeting with the utility and Watershed Protection so she can have a better understanding of the situation.

Meszaros later told the Austin Monitor that if the lake were lowered five to 10 feet, the zebra mussels would die. But that could be “a potentially overpowering event. That’s what we’ve been thinking through with Watershed and others … the stench would be unbearable … nobody would want a month or two where the stench was unbearable. We don’t know, but those are things we would want to work through as a community.”

Meszaros told the Monitor that LCRA has no plans to lower the lake during the next year or two because the agency is working on Mansfield Dam, a $10.5 million, decadelong project that involves removing one or two gates at a time and rehabilitating them, according to the agency’s website.

The tiny mussels have also gotten into the pipes Austin Water uses to process raw water. Meszaros said the utility plans to use copper sulfate to get the mussels out of the pipes. He said the cost of such treatment would be several hundred thousand dollars spread over the three water treatment plants.

The director said he would be bringing forward a request for Council to authorize the expenditure in the near future.

He stressed that Austin Water would not be using the chemical on intake pipes. Those pipes have to be cleaned mechanically, he said. “We’ve done a lot of work to get ready for that and evaluate options, so the chemical purchase for that is coming in January.”

Photo by the U.S. Department of Agriculture.

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