BUFFALO, N.Y. — The shimmering waters of the Great Lakes and their connecting channels are iconic, providing recreation, commerce, and vital ecosystems. But beneath the surface, an aggressive invader threatens this beauty: Hydrilla.
The U.S. Army Corps of Engineers, Buffalo District, is leading a multi-faceted effort to control this invasive aquatic plant and protect the health of the Great Lakes Basin ecosystem and the communities that depend on it.
Hydrilla (hydrilla verticillata) – commonly known as waterthyme – is a non-native, submerged aquatic plant originally from Eurasia. Introduced to the United States in the 1960s, it has spread throughout freshwater waterways adjacent to Lake Erie, including the Finger Lakes, the Niagara River, and the Erie Canal. Its rapid growth and resiliency pose significant challenges.
“Hydrilla is a particularly problematic invasive species because of its ability to reproduce through fragmentation,” said Buffalo District Biologist Michael Voorhees. “Even a small piece of the plant can establish a new colony. This makes eradication extremely challenging, and ongoing control measures crucial.”
The Threat to Communities
The ecological and economic impacts of uncontrolled hydrilla are substantial.
Growth of hydrilla in dense mats can impede navigation, hindering recreational boating. It can clog intake pipes for power plants and water treatment facilities, increasing maintenance costs and potentially disrupting essential services. Recreational activities like fishing, swimming, and waterskiing can become difficult or impossible in heavily infested areas.
Beyond the direct economic costs, hydrilla disrupts natural ecosystems.
It outcompetes native aquatic plants like eelgrass, coontail, American waterweed, and pondweeds, reducing biodiversity and impacting fish populations. The dense mats reduce oxygen levels in the water, potentially leading to fish kills, and the altered habitat impacts waterfowl and other wildlife dependent on a healthy aquatic environment.
“The presence of hydrilla isn’t just an environmental concern; it’s a community concern,” said Dave Schulenberg, Buffalo District chief of planning. “We’re talking about impacts to tourism, fishing industries, and the overall enjoyment of our Great Lakes Basin resources.”
More than a Decade of Dedication
The U.S. Army Corps of Engineers is authorized to treat hydrilla under Section 104 of the River and Harbor Act of 1958, through the Aquatic Plant Control Research Program.
The Buffalo District’s commitment to controlling hydrilla began in 2012 with initial monitoring that revealed the growing presence of the invasive plant in key waterways. Early efforts focused on mapping infestations and understanding the extent of the problem. Since then, the district has consistently monitored hydrilla populations.
Initial treatments began in 2013. For most of the past twelve years, the district’s efforts have been funded by the U.S. Environmental Protection Agency through the Great Lakes Restoration Initiative.
The district’s focus has consistently been on developing and demonstrating innovative ways to treat monoecious hydrilla in high water exchange environments. Over the years, it expanded monitoring and treatment efforts to multiple target areas, adapted control strategies based on ongoing research and evaluation, and refined techniques to maximize effectiveness and minimize environmental impacts.
Monoecious hydrilla is a genetic variant of the plant that has both male and female flowers and presents additional challenges due to its ability to produce seeds – increasing its potential to spread and persist.
The district has shown significant success with well-timed treatments that use lower herbicide application rates – effectively controlling hydrilla while minimizing chemical use.
“We’ve demonstrated that you don’t always need the maximum recommended dose to achieve effective control,” said Voorhees.
This approach reduces environmental concerns and lowers treatment costs, saving valuable time and resources.
A Targeted Approach
The Buffalo District employs a comprehensive, tailored approach to hydrilla control. It includes a combination of preventative measures, early detection, and targeted treatments.
This year, the district is focusing on treating key areas within the Erie Canal, Niagara River, and Cayuga Lake at Ithaca and Aurora with aquatic herbicides.
Herbicide applications are carefully planned and executed, using low doses of products approved by New York State and the U.S. Environmental Protection Agency to target hydrilla while minimizing harm to other aquatic plants and organisms.
“Safety is our top priority,” said Buffalo District Biologist Richard Ruby. “Before any herbicide application, we conduct thorough water quality testing and continue to monitor water quality during and after the treatment to ensure compliance with all applicable environmental regulations.”
Biologists like Voorhees and Ruby collect plant and tuber samples and use hydro-acoustic technology to gather detailed measurements of hydrilla volume and growth. They also work closely with students and professors at colleges across the region to perform surveys and data collection independently, building on the district's capacity for tackling hydrilla.
Shared Responsibility
Recognizing that hydrilla control is a shared responsibility, the Buffalo District actively collaborates with partners at the federal, state, and local level. Some of the more frequent ones include the USACE Engineer Research and Development Center, the U.S. Fish and Wildlife Service, the New York State Department of Environmental Conservation, and the Finger Lakes and Western New York chapters of the Partnership for Regional Invasive Species Management.
“We can’t do this alone,” said Ruby. “Effective hydrilla management requires a coordinated effort across all levels of government and with the support of the public.”
The district actively participates in public meetings and shares information with communities where hydrilla treatment takes place. Printed materials, digital documents, and signage at public access locations around waterways are among the ways they ensure outreach during the summer hydrilla control season. Updates are also shared through the district’s website and social media channels.
“We encourage everyone to be vigilant and report any areas where they suspect hydrilla is growing,” said Ruby. “Early detection is critical to preventing further spread.”
Remaining Vigilant
The Buffalo District has demonstrated significant success in containing and reducing hydrilla infestations within its area of responsibility. Through consistent monitoring and adaptive management strategies, the plant’s spread has been minimized – in some cases seeing up to 90% eradication or more.
Control methods continue to be refined, maximizing efficiency and minimizing environmental impacts.
2025 marks the final year of full-scale treatment as part of the district’s demonstration efforts. However, their team remains committed to sharing its knowledge and expertise.
Beginning in 2026, the district will provide two years of technical assistance and monitoring to partner agencies and stakeholders, such as NYSDEC, pending continued funding availability.
The Buffalo District remains dedicated to protecting the Great Lakes Basin ecosystem and the communities that rely on it, through continued monitoring, targeted control efforts, and collaborative partnerships to stem the spread of hydrilla.
This article was written with assistance from artificial intelligence.
The Buffalo District delivers world class engineering solutions to the Great Lakes Region, the Army and the Nation to ensure national security, environmental sustainability, water resource management, and emergency assistance during peace and war. Learn more at www.lrd.usace.army.mil/buffalo
For 250 years, the U.S. Army Corps of Engineers has been at the forefront of the nation’s engineering excellence, responding when called. From constructing fortifications during the Revolutionary War, to building the infrastructure that saw America’s strength grow militarily and economically, USACE’s mission has always been to deliver engineering solutions for our nation’s toughest challenges. Learn more about the USACE 250th anniversary at www.usace.army.mil/Home/250th