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Lake & Rivers Local News

CLWSC Discovers Zebra Mussels in Pipes

This image of zebra mussels in Canyon Lake is courtesy of Texas Parks and Wildlife Department.

Canyon Lake Water Service Company (CLWSC) is asking all customers to limit water usage after zebra mussels were discovered blocking intake pipes at its Canyon Lake Shores treatment plant.

Water production is temporarily restricted and water storage reduced, CLWSC advised in email and phone-call blasts around 6 p.m. Tuesday, July 23. As of Friday, July 26, this advisory remains in effect.

Customers are asked to limit water usage to essential indoor use only so the company can maintain water-storage levels.

“This helps ensure the health and safety of our community,” CLWSC said in its email. “Thank you for your understanding in this matter.”

Canyon Lake Shores treatment plant supplies water to customers on the north side of Canyon Lake as well as the Highway 281 corridor from the Comal/Blanco county line south to Bulverde.

Zebra mussels can clog water intakes, damage or increase maintenance on hydroelectric and other facilities using raw surface water, and damage boats and motors left in infested waters.

Zebra Mussels Foul Austin’s Water Supply

Over the last several years, the invasive mollusks have been found on screens around intake pipes feeding Austin’s water supply from Lake Travis.

Remedies include hiring divers for regular inspections and pressure-washing mussels from screens and, using chemical treatments to fend mussels off.

In February, Austin’s water turned smelly after zebra mussels attached themselves to a 72-inch raw water pipeline undergoing repairs in west Austin.

Mussels Discovered in Canyon Lake in 2017

Texas Parks and Wildlife Department (TPWD) fisheries biologists and game wardens confirmed the presence of zebra mussels at Canyon Lake in June 2017.

Employees at Canyon Lake Marina noticed the zebra mussels while working on a boat that had been stored in a slip at Crane’s Mill Marina and contacted TPWD to report the discovery and to get verification.

“This is the first positive documentation of zebra mussels in Canyon Lake and in the Guadalupe River Basin,” said Brian Van Zee, Inland Fisheries regional director for TPWD. “Although marina staff have intercepted several incoming boats over the years that had invasive mussels attached, it is essential that boats stored on infested lakes be decontaminated before they’re moved as they are a key pathway for spreading this invasive species.”

The rapidly reproducing zebra mussels, originally from Eurasia, can have serious economic, environmental and recreational impacts on Texas reservoirs and rivers. Zebra mussels can cover shoreline rocks and litter beaches with treacherously sharp shells, clog public-water intakes, and damage boats and motors left in infested waters.

“It’s very unfortunate not only for the reservoir but also for downstream resources – including the Guadalupe River and the reservoirs downstream from Canyon Dam,” Van Zee said.

About CLWSC:

According to clwsc.com, Canyon Lake Water Service Company is a state-regulated investor owned utility providing water service to approximately 36,000 people through more than 13,400 connections in Comal and southern Blanco Counties.

The original Canyon Lake Water Supply Corporation became an operating entity in 1994 as a member-owned non-profit water utility, consolidating 46 separate ground water systems. Founders recognized that groundwater supplies alone were inadequate to support the water demands of a growing community and that centralized surface water treatment plants would make it possible to distribute surface water from Canyon Lake to the residents in Comal County. Since the original acquisition of the Supply Corporation in 2006, CLWSC has grown from approximately 6,000 connections to over 13,400 connections by both acquisition of neighboring systems, growth from new development and organic growth in existing subdivisions.

Service Area
Canyon Lake is located on the Guadalupe River in the Texas Hill Country. The CLWSC service area surrounds Canyon Lake and includes approximately 250 square miles within Comal County and southern Blanco County. CLWSC infrastructure includes over 590 miles of pipes, three surface water treatment plants and over forty active wells located throughout the system. The company currently operate three wastewater treatment facilities and a fourth is under construction, all in Comal County.


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  1. Lisa Deemer July 25, 2019

    Are they good to eat?

  2. Bob House July 24, 2019

    How are they going to resolve this and how long will it take?


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