BRA deploys new tool against zebra mussel invasion

Copper is the latest line of defense from zebra mussels as the Brazos River Authority works to safeguard infrastructure at Stillhouse Hollow Lake.

Zebra mussels are an invasive species, an unrelenting tide of destruction that, if left unchecked, can choke the equipment that brings our communities the water they depend upon to survive.

At only 1.5 inches, these silent invaders can accumulate to the point of creating problems for pipes that transfer water to the communities, homes, and businesses that depend on it.

This summer, a new process will go online in Bell County that will hinder zebra mussel development within the system components of the Williamson County Regional Raw Water Line (WCRRWL). The BRA operates, manages, and maintains the water line and associated facilities for the cities of Georgetown and Round Rock and the Brushy Creek Municipal Utility District, which share ownership of the line. And it's that line that conveys raw water from Stillhouse Lake Hollow to Lake Georgetown.

The project started a few years ago when the BRA contracted with the engineering firm Walker Partners, LLC. to evaluate zebra mussel control strategies for this critical infrastructure. From this, the idea of a copper ion generator was born. Peabody General Contractors were contracted for the work.

This new copper ion generator system will use very low-level dosing of a copper solution to protect this water transportation system, said Brad Brunett, BRA chief operations officer.

"Zebra mussels don't like the copper solution, so they won't colonize and create problems in our pumps and cooling systems," Brunett said. "This is the most feasible and economical solution given all the different components of the infrastructure. The infrastructure we have was all built before zebra mussels came into existence at these lakes. Regardless, it's impossible to build everything out of zebra mussel-resistant materials because some of the equipment couldn't be constructed from those materials."

Near the reservoir, a copper ion generator creates the treatment solution in a dedicated building. An intake structure above Stillhouse Hollow Lake pulls water from the reservoir to transfer it to Georgetown Lake. The pumps under the lake's surface that lift the water into the intake structure have screens. It's at these screens that the copper solution will be injected, Brunett said.

The increased copper concentration will hinder zebra mussel development within the WCRRWL system components, which will protect this critical infrastructure and increase the reliability of water transportation to meet area needs. Parts of the infrastructure, such as pump motor cooling systems, have smaller tubing and pipes that, if clogged by zebra mussels, would cause the motors to burn out, Brunett said.

"We have to be doing everything we can to make it as resilient and reliable as we can," Brunett said. "A lot of people rely on this pump station for their water supply."

Brunett said there are several other organizations across the nation using similar methods. The U.S. Army Corps of Engineers reported in 2021 that two projects within USACE Omaha District's area of operations were finding alternative ways to combat zebra mussels. Big Bend Dam was in the planning phases of installing copper ion generators, while Fort Randall in South Dakota was in its planning phase for the direct injection of copper-based sulfate pentahydrate. Read more about that here.

At Stillhouse Hollow Lake, the solution will be injected at such low concentrations there aren't any health impacts to the people who enjoy the lake or depend on its water supply or the fish that call this area home, Brunett said.

Tiffany Malzahn, the BRA's chief environmental officer, said that as part of the project, toxicology analyses were performed to identify dosing that would ensure the project's compliance with Texas surface water quality standards for human health and aquatic life exposure to copper.

Zebra mussels were discovered in Stillhouse Hollow Lake and Lake Georgetown in 2016 and 2017, respectively. These invasive creatures have a high reproductive capacity, meaning it doesn't take long for them to quickly get out of hand, Malzahn said. One zebra mussel can produce up to one million microscopic larvae per year, according to Texas Invasives.

"There are cases all around the country of zebra mussels clogging intake structures, interfering with reservoir gates, pipelines, even boats and dock structures," she said.

Thankfully, not every lake in the Brazos River Basin has zebra mussels. There are actions you can take to help stop the spread of zebra mussels into lakes that are not infested.

The popular saying is, "Clean, Drain, Dry," meaning any time you remove a watercraft from a Texas reservoir infested with zebra mussels, it's important to fully clean it, the trailer, and gear by removing all plants and foreign objects. Next, drain all the water from the boat, including the motor, bilge, live wells, and bait buckets, before leaving the lake. And finally, dry the boat and trailer for a week or more before entering another water body. If unable to let it dry for at least a week, wash it with a high-pressure washer and hot (at least 140-degree), soapy water, according to the Texas Parks & Wildlife Department.

Zebra mussels have been a Texas-sized headache since their first identification in the Lone Star State in 2009 when they were found at Lake Texoma, according to the Texas Parks & Wildlife Department. Seven river basins across the state have them – the Red, Trinity, Brazos, Colorado, Guadalupe, San Antonio, and Rio Grande river basins. Unfortunately, 33 lakes in Texas are classified as fully infested with zebra mussels, which means the water body has an established reproducing population, according to the Texas Parks & Wildlife Department.

It's not just a request. It's the law.

It's not just important to help stop the spread of these invasive species because they can damage water transportation systems. Zebra mussels can cause tremendous environmental and economic damage, hurting aquatic life by taking over habitats from native species, damaging lake ecology and affecting fish populations, damaging boats, and hindering water recreation, according to Texas Invasives. They can survive for days in water trapped in a boat.

Four out of the 11 reservoirs in the BRA Water Supply System have zebra mussels – the other two being lakes Belton and Granger. At this time, there are no zebra mussels in the three Brazos River Authority-owned and operated reservoirs: lakes Possum Kingdom, Limestone, and Granbury.

Do your part to help stop the spread of zebra mussels: Clean, Drain, Dry.

The state requires every boat owner to drain the water from boats and onboard receptacles when leaving or approaching public fresh waters. This rule applies at all sites where boats can be launched and includes all types and sizes of boats, whether powered or not, personal watercraft, sailboats, kayaks/canoes, or any other vessel used to travel on public waters. The penalty for the first offense is a fine of up to $500. The penalty for a repeat offense is a fine of up to $2,000 and/or up to 180 days in jail, according to the TPWD.

Zebra mussels, which are named after dark, zig-zagged stripes on each shell, create big problems. And it can cost big money to address infestations.