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TPWD Investigates Reports That Hydrilla’s Showing Up in Canyon Lake

Vegetation in Canyon Lake is usually limited and fluctuates through the years, but hydrilla and native pondweeds could be making a comeback due to a mild winter and stable lake levels. File image.

Hydrilla, a submerged aquatic invasive plant, could be making a comeback in Canyon Lake thanks to a mild winter and stable water levels since 2018.

Texas Parks and Wildlife Department (TPWD) Biologist Patrick Ireland, who works out of the Inland Fisheries Division in San Marcos, spent Monday out on the water looking for it.

“Our previous vegetation/habitat survey was performed in August of 2019,” he said in an email. “During that survey, very little vegetation was found on the lake. However, we have recently — this summer — been getting quite a few reports of hydrilla and other aquatic vegetation showing up in the lake.”

TPWD performs routine vegetation surveys on Canyon Lake every three or four years to keep tabs on the aquatic habitat, Ireland said. Historically vegetation in Canyon Lake is limited and fluctuates through the years.

But this week’s visit was geared toward finding areas of higher plant density and gathering enough data to get a good grasp on the number of aquatic plants like hydrilla and pondweed actually in the reservoir.

“The results from this survey will be used to help guide our process for management decisions when we work with our partners and the controlling authority,” he said.

“Once we process the data from today’s survey, we should have a very good idea of the current status of the hydrilla in the reservoir.” –TPWD Biologist Patrick Ireland

Ireland recorded the spatial location and extent of hydrilla in Canyon Lake. Data collection included finding and recording the location of both submerged and ‘topped-out’ hydrilla that’s reached the surface of the lake.

“To do this, we use sonar and visual observations as well as a vegetation rake to confirm what we are seeing underwater,” Ireland said. “All of this data is recorded in our field notes as well as a precision GPS system. Once we process the data from today’s survey, we should have a very good idea of the current status of the hydrilla in the reservoir.”

TPWD drafts updated reports for most of its water bodies every four years.

According to its website, overabundant vegetation can limit recreational access, restrict flow rates in canals and rivers, interfere with industrial water uses and harm fish and wildlife.

In recent decades, species such as hydrilla, water hyacinth and giant Salvinia have invaded many Texas waterways. They travel from one watershed to another by way of boat propellers, bilges and livewells.

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  1. Tommy August 8, 2022

    The only reason canyon lake is kind of good for fishing is because of that, also the hydrilla is only really by the river, there is barely anything up by the dam and main lake.

  2. robert s July 7, 2022

    we are on the lake almost every weekend. the area up by the river is getting worse year by year and has also spread to other parts of the lake, almost to the dam.
    i really do hope tpwd has a plan for it so parts of the lake dont become inaccessible as well as dangerous

  3. John G Bowles September 7, 2021

    I was just a canyon lake near boat ramp 23 and also to direction to river is very very bad this plants are growing way out if control someone needs to talk to who is responsible for this plant and or ttying to stop ir remove plant this will distry this lake at rate its growing this is bad.

  4. Clayton June 29, 2021

    Last weekend (June ‘21) I was 10 to 15 yards from the shore, I jumped in and was struggling to get through the Hydrilla. It was poor judgement on my part to jump in without my pfd and I own that but I would not have made it to shore without assistance. I’m an average swimmer, the Hydrilla was a foot below the water and made it impossible for me to get to shore. A health lake is important for the environment but a life threatening situation begs one to ask is this safe over all. We have posted signs for all to know about the danger of the Hydrilla. I‘m sharing this so other do not have the same experience, we need to minimize the Hydrilla growth and promote the dangers it presents.

  5. Jim Haas June 4, 2021

    On a recent boat ride up the lake 5/29/21 past Cranes Mill Park up in the river some areas Hydrilla was solid in some coves and expanding from bank-to-bank in the river waterways a substantial increase from the year before.

  6. Rick July 16, 2020

    Best thing that could happen to canyon lake and river both is hydrilla.


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