Tests Conducted On Larvae At Canyon Lake Determine A Presence Of Zebra Mussels
The positive finding places all of the reservoirs downstream of Canyon Lake, including Lake Dunlap, Lake McQueeney, Lake Placid, Meadow Lake, Lake Gonzales (H-4), and Lake Wood (H-5) at risk of invasion as zebra mussel larvae disperse downstream.
CANYON LAKE, Texas — After a watercraft in the Cranes Mills Marina area of Canyon Lake recently showed signs of what appeared to be zebra mussels, Texas Parks and Wildlife Department (TPWD) officials conducted larvae testing and determined zebra mussels actually are present in the lake.
Native to the lakes of Russia and Ukraine, zebra mussels are small freshwater mollusks that are invasive to the waters of the United States. The first Texas infestation of this invasive species was found in Lake Texoma in 2009. Zebra mussels, which have no native predators, have sharp shells and multiply rapidly, can negatively affect native fish, become beach hazards, damage boats and boating equipment, and clog water intakes.
The U.S. Army Corps of Engineers (USACE) constructed Canyon Lake for flood control and water supply, with the Guadalupe-Blanco River Authority (GBRA) as the local sponsor. Of the 378,852 acre-feet (a/f) of water stored at Canyon Lake, 90,000 a/f is permitted as water supply managed by GBRA.
The positive finding places all of the reservoirs downstream of Canyon Lake, including Lake Dunlap, Lake McQueeney, Lake Placid, Meadow Lake, Lake Gonzales (H-4), and Lake Wood (H-5) at risk of invasion as zebra mussel larvae disperse downstream.
“Even with the TPWD positive determination for the presence of zebra mussels in Canyon Lake, we want to ensure our customers that it does not negatively affect the safety of their drinking water,” GBRA General Manager Kevin Patteson said. “However, the presence of zebra mussels in the river basin will prompt our due diligence with respect to all of GBRA’s water intake structures and treatment facilities, which will include an ongoing monitoring and inspection regiment,” he added.
GBRA and TPWD staffs regularly conduct sampling at designated areas at Canyon Lake and along the Guadalupe River. Patteson said additional monitoring and evaluation may be necessary to determine potential long-term impacts and treatment options for Western Canyon Water Treatment Plant and intake structures. TPWD staff also began inspecting other marinas at Canyon Lake. Information they collect will help in evaluating potential future impacts below Canyon on infrastructure and habitat.
TPWD defines a water body having an established, reproducing population of zebra mussels as “infested,” and have determined the mussels in Canyon Lake meet their criteria for the designation. Patteson said GBRA plans to employ more signage in appropriate areas regarding cleaning requirements for boats and other watercraft in an effort to prevent the mussels from spreading to other water bodies and explained that GBRA already is a partner with TPWD in its “Clean, Drain, Dry Your Boat” campaign to curtail the spread of zebra mussels on Texas lakes. TPWD staff will work with the USACE on specific ramp signage at Canyon Lake.
To find out more about zebra mussels and their potential impacts, please visit tpwd.texas.gov/ZebraMussels.
The GBRA was established by the Texas Legislature in 1933 as a water conservation and reclamation district. GBRA provides stewardship for the water resources in its 10-county statutory district, which begins near the headwaters of the Guadalupe and Blanco rivers, ends at San Antonio Bay, and includes Kendall, Comal, Hays, Caldwell, Guadalupe, Gonzales, DeWitt, Victoria, Calhoun, and Refugio counties. GBRA’s website: www.gbra.org
