CANYON LAKE, Texas – If you’ve been to Canyon Lake recently you might have noticed some green stuff floating on the lake’s surface — turns out it is an aquatic plant called hydrilla.
KSAT reached out to the Texas Parks and Wildlife Department and heard back from officials with the Inland Fisheries Division who said hydrilla appeared in Canyon Lake in early 2020.
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Hydrilla is listed as a prohibited exotic species, so its deliberate introduction to any waterbody in the state is unlawful, according to TPWD.
Inland Fisheries officials said despite the recent presence of the plant, the coverage of hydrilla at Canyon Lake has not exceeded 10% of the reservoir’s surface area.
“The ongoing drought and lack of flow from the Guadalupe River has likely played a role in this growth as declining water levels are conducive to submerged aquatic plant growth,” TPWD said in an email to KSAT. “Canyon Lake is not alone in experiencing hydrilla growth as many reservoirs in Central Texas are also experiencing a similar phenomenon given the weather we’ve had the last few years.”
A spokesperson for Inland Fisheries said as of this summer, Canyon Lake water levels have declined to near all-time lows.
“This has also pushed the hydrilla to deeper depth contours as low water is allowing sunlight to reach deeper,” officials said.
TPWD is expected to conduct a full vegetation survey of Canyon Lake in the next few weeks to document the vegetation and hydrilla coverage.
Officials said the presence of hydrilla shouldn’t disrupt recreational use lake-wide but it could represent an acute concern for some people at the upper end of the reservoir.
“At Canyon Lake, TPWD is coordinating closely with the U.S. Army Corps of Engineers, which is the reservoir controlling authority, is the landowner of the Canyon Lake shoreline, and is ultimately responsible for making the decision on whether any treatment of hydrilla will occur and the specific treatment methods to be used,” the spokesperson said.
TPWD is also coordinating with officials from the Water Oriented Recreation District of Comal County, Guadalupe-Blanco River Authority, Canyon Lake Bass Club, area residents and other stakeholders who participate in water-related recreation on Canyon Lake to identify management strategies.
Inland Fisheries officials said any treatment plan for the hydrilla will also take into consideration the potential effects on the local fish, impacts to stakeholders and reservoir use.
“TPWD recognizes the positive impact hydrilla can have on largemouth bass populations, angling opportunities, and related local economic benefits as reservoirs age, while also recognizing hydrilla can become invasive and negatively impact access to the water, recreational boating (i.e., impeding navigation), and operations by controlling authorities,” the spokesperson told KSAT. “TPWD carefully considers all these perspectives when making recommendations to the controlling authority.”
A publication from TPWD posted in January states that issues with hydrilla in Texas reservoirs frequently resolve themselves over time with no treatment because of environmental conditions not conducive to aquatic plant growth, such as floods, droughts, water level fluctuations, cold winter water temperatures, or extended periods of high turbidity.
The publication also states that when total vegetation coverage is less than 40% of the reservoir surface area, the Inland Fisheries Division will typically recommend conducting hydrilla treatments in areas where public access is impeded. Those areas could include boat ramps, fishing piers, swimming areas, shorelines of campsites and boat lanes.
KSAT has also reached out to the U.S. Army Corps of Engineers for comment.