When was hydrilla found in Texas?

Hydrilla was first discovered in Texas in the mid-1970s, rapidly spreading across the state's massive, interconnected reservoir systems via recreational boat traffic.

Why is hydrilla dangerous for Texas?

Texas relies heavily on man-made reservoirs for drinking water and agricultural irrigation. Hydrilla can completely clog the intake pipes at these critical municipal and agricultural facilities.

Does Texas use grass carp for hydrilla?

Yes, Texas Parks and Wildlife heavily utilizes permitted, sterile (triploid) grass carp to manage hydrilla in large reservoirs like Lake Conroe.

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Hydrilla in Texas: Reservoir Invasions

Discover how hydrilla impacts the massive man-made reservoirs of Texas, threatening water supplies, hydroelectric dams, and bass fishing tournaments.

The Reservoir Problem

Unlike Florida, which is dominated by natural shallow lakes, Texas's surface water is largely contained in massive, man-made impoundments and reservoirs. When Hydrilla verticillata entered the state in the 1970s, it found a perfect home in the shallow, nutrient-rich coves of these sprawling systems.

Because these reservoirs act as critical infrastructure for municipal drinking water, agricultural irrigation, and hydroelectric power generation, hydrilla presents a severe operational threat to the state.

High-Profile Battles in Texas

Lake Conroe: Perhaps the most famous hydrilla battleground in Texas. In the 1980s, the lake was completely choked. The state stocked massive numbers of grass carp, which eradicated the hydrilla but also wiped out the native vegetation, creating a years-long debate between homeowners (who wanted clear water) and bass anglers (who wanted fish habitat).
Sam Rayburn Reservoir & Toledo Bend: These massive East Texas reservoirs (world-famous for bass fishing) require constant monitoring. Texas Parks and Wildlife (TPWD) works closely with angler groups to manage the weed to maintain fish habitat while keeping boat lanes clear.
Lake Austin: Frequent battles with hydrilla restricting water flow and recreation on this critical stretch of the Colorado River have led to complex integrated pest management plans using drawdowns, carp, and herbicides.

Management Approach

Texas Parks and Wildlife (TPWD) strictly regulates the treatment of aquatic vegetation. Because of the size of the reservoirs, large-scale herbicide treatments are often prohibitively expensive.

Therefore, Texas relies heavily on biological control via sterile triploid grass carp. The state requires strict permitting and the installation of fish barriers on spillways to prevent the carp from escaping into river systems before they can be stocked.

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Frequently Asked Questions About Hydrilla in Texas: Reservoir Invasions

References

Information presented on this page is supported by peer-reviewed research, federal agencies, and state resource management programs.

U.S. Geological Survey (USGS) – Nonindigenous Aquatic Species Databasehttps://nas.er.usgs.gov
U.S. Army Corps of Engineers – Aquatic Plant Control Research Programhttps://www.erdc.usace.army.mil
NOAA Aquatic Invasive Species Programhttps://www.noaa.gov