Aquatic Weed Control Program | NC DEQ

Aquatic Weed Control Program | NC DEQ
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The purpose of the Aquatic Weed Control Program is to provide units of local government and residents of North Carolina with resources that will promote the prevention and management of noxious aquatic weed infestations. The philosophy is that by offering assistance and developing partnerships, aquatic weeds will be more efficiently managed across the state.
The program's two primary objectives are:
Respond to localized infestations to mitigate the long-term economic and environmental impacts that noxious aquatic weeds impose.
Reduce the frequency of aquatic weed introductions through education and public awareness.
The philosophy of the program applies to aquatic weed infestations of all sizes. Large-scale projects can be complex and challenging. They may span jurisdictions and require the development of partnerships.  Aquatic weed control projects may involve federal, state and local governments as well as non-government organizations and private landowners.  The program often serves as a major contributor of funding and provides leadership on large-scale projects. Benefits are realized by offering assistance for small-scale projects as well. Allowing aquatic weeds to persist and spread throughout our waterways only exacerbates the problem.
The
NC Aquatic Nuisance Species Management Plan
provides a detailed explanation of why aquatic weeds are problematic, pathways of introduction and associated laws.
For Public Waters, This Program Can Provide:
Financial Assistance
Technical Assistance
Operational Support
Aquatic Plant Identification
Treatment Recommendations
Financial assistance and operational support are in the form of cost-share arrangements and are available to Counties, Municipalities, Soil & Water Districts, Drainage Districts, Public Utilities, and other government agencies.
Program staff provide a range of fieldwork services including site assessments, aquatic vegetation surveys and aquatic weed management operations.  To provide these services, the program utilizes specialized equipment.  Staff are trained on this equipment and have aquatic herbicide applicator licenses.
How to Apply for Financial Assistance:
A telephone call, letter or email may serve as the initial communication.  Be prepared to describe the problem in detail.
Program staff will need to conduct a site visit in most circumstances.
Submit a grant application.
Download application form.
Applications must be received no later than October 15 the year before the project begins.
Applications will be considered for inclusion in the work-plan for the following year.
For Private Waters, This Program Can Provide:
Technical Assistance
Aquatic Plant Identification
Recommend Treatments
Private landowners can also contact their county offices of the
Agricultural Extension Service
for further assistance.
The NCDEQ has designated specific plants as Noxious Aquatic Weeds. The list of noxious aquatic weeds was populated by first adopting all the plants that are federally listed. The list was then expanded by including additional exotic plants that are either known to express invasive behavior in North Carolina or are very likely to become problematic if introduced to North Carolina waters.  The plants designated by NCDEQ as noxious aquatic weeds are written into the North Carolina Administrative Code.
The Complete List of NCDEQ Noxious Aquatic Weeds - 15A NCAC 02G .0602
The aquatic weeds on the table below are either actively under management or were part of a management project in recent years.
Aquatic Weeds
Common Name
Image
Scientific Name
Web Resources
Distribution Maps
Regulated by NCDA ?
Alligatorweed
Alternanthera philoxeroides (Mart.) Griseb
USDA
UF/IFAS
EDDMaps
USGS
Brazilian Waterweed Anacharis
Egeria densa Planch
USDA
UF/IFAS
EDDMaps
USGS
Brittleleaf Naiad
Najas minor All.
USDA
EDDMaps
USGS
Creeping Water Primrose
Ludwigia hexapetala (Hooker & Arnott) Zardi.
USDA
UF/IFAS
EDDMaps
USGS
YES
Eurasian Watermilfoil
Myriophyllum spicatum L.
USDA
UF/IFAS
EDDMaps
USGS
YES
Giant Salvinia
Salvinia Molesta Mitch
USDA
UF/IFAS
EDDMaps
USGS
YES
Hydrilla
Hydrilla verticillata (L.f.) Royle
USDA
UF/IFAS
EDDMaps
USGS
YES
Parrot Feather
Myriophyllum aquaticum (Vell.) Verdc.
USDA
UF/IFAS
EDDMaps
USGS
Phragmites
Phragmites australis (Cav.) Trin. Ex. Steud
USDA
UF/IFAS
EDDMaps
USGS
Water Hyacinth
Eichhornia crassipes (Mart.) Solms
USDA
UF/IFAS
EDDMaps
USGS
Problems Associated with Aquatic Weeds
Divert water flows causing erosion and flooding.
Impede recreational activities like swimming, fishing, boating, and water sports.
Displace native vegetation which can alter community structure and degrade ecological functions.
Form dense growths that become navigation hazards.
Clog water intake systems of industries, municipalities and irrigators.
Create/expand breeding habitat for mosquitoes and other pests.
Aquatic weeds become more difficult and expensive to control if ignored -- rapid response to developing infestations can reduce the damage caused by noxious weeds and the cost of controlling them.
For more details read
Economic & Environmental Impacts of NC Aquatic Weed Infestations
Control Methods
Once a non-native species has been introduced into a body of water, many control methods are considered based on cost and effectiveness to treat it. Depending on the specific conditions of different water bodies, one method of control might be more desirable than another (e.g. herbicides would be preferable over biological control methods in a river due to the constant motion). Often times more than one method is used to swiftly and efficiently tackle the problem. Below are the methods used by the Aquatic Weeds Control Program:
Grass Carp
Ctneopharyngodon idella
) are an herbivorous fish native to Asia and are quite effective at eradicating aquatic weeds. They are introduced into bodies of water such as lakes or ponds to help with the treatment of non-native plants. While they prefer invasive plants such as Hydrilla, they don't discriminate and will eat the native vegetation as well. Because of this, sterilized Grass Carp known as Triploid Grass Carp are used to prevent them from reproducing and outcompeting the native fish species. The amount of these Carp stocked is dependent on the specific body of water and is carefully calculated to minimize impact to the native vegetation. After a few years, the carp will die out and allow for the native species to continue to flourish as native vegetation returns in place of the invasive weeds.
For more information on Grass Carp, visit this
blog post
from the Department of Water Resources
Insects
such as Salvinia Weevils (
Cyrtobagous salviniae
) and Alligator Weed Beetles (
Agasicles hygrophila
) are another biological control method used on specific sites to aid in treatment. Unlike Grass Carp, these insects are monophagous meaning they only consume the target plant. Salvinia Weevils are only known to eat Salvinia and Alligator Weed Beetles are known to eat Alligator Weed. These insects have a short lifespan (~2 months), a quick reproduction cycle, and they don't consume a lot of biomass, so they are stocked in large quantities. The use of insects is often used in conjunction with herbicidal treatments to further hinder the spread of invasive plants. The success of this treatment method is not always consistent as these insects need a food source year-round and do not always survive Winter. This can lead to an uptick in infestation of the target plant the following season.
Herbicide
is a common and efficient method for aquatic weed control that can be used to directly target plants. Different plant species respond to different herbicides at higher or lower concentrations. When creating a treatment plan with aquatic herbicides, the specific herbicide(s) are chosen based on the target weed and environmental conditions of the water body. The concentration of the herbicide is carefully calculated to minimize cost and damage. It is important not to use too much as this can be detrimental to the ecosystem and the public. Between herbicide applications, water samples can be collected and tested to determine the concentration of herbicide that remains in the water months after an application. Depending on the results of the test and the effects on the invasive plants, the amount of herbicide may be adjusted for future applications to change the concentration.
Harvesting (Physical removal)
of invasive plants has proved ineffective and arduous. Some species, such as Hydrilla, are able to survive and reproduce via fragmentation, so if even a few fragments are not removed, the infestation will spread and flourish again.
Water Drawdown
is sometimes used for aquatic weeds such as Giant Salvinia or to survey sites, but it is overall an ineffective control method as ponds and lakes can only have so much of the water drained without causing permanent adverse effects to the ecosystem. Some species of aquatic weeds are also able to survive droughts for extended periods of time. Artificial droughts are therefore used more for surveying and site maintenance than for weed control.
Each of these methods will of course have their respective drawbacks. When creating a treatment plan many of the following are to be considered:
Method
Mechanical (Harvesting)
Pros:
Control around water intake
Immediate results
Cons:
Ineffective in shallow water
Plant matter must be disposed of
Removes desirable species
Biological (Carp/insects)
Pros:
Long-term control
Reduced environmental concerns
Cons:
Potential for escape
May eliminate desirable plants
Chemical (Herbicide)
Pros:
Site-specific
Rapid response
Cons:
May have water use restrictions
Short-term control
Physical (Water Drawdown)
Pros:
Effective in shallow areas
Inexpensive
Cons:
May reduce recreation
Promotes erosion
Depends on use of water body
Prevention
The best way to protect your waters is to prevent invasive species from entering all together. Public meetings, online posts, literature, signage, cleaning stations, workshops, and more are all helpful resources that are available to keep the public informed and up to date. Invasive species are often spread by people, so the best way to prevent them is to stay informed, maintain proper practices, and spread the word. If you believe you already have an invasive plant species in your waters, you can report a sighting with
Duke Energy's Plant Reporting Tool
to help prevent it from spreading.
Below are some more resources about proper boating practices and methods to prevent the spread of invasive species.
NC Wildlife Commission's Prevention Methods for the Spread of Aquatic Nuisance Species
NC Wildlife Commission's Boating Ramps
For more information about how to Stop Aquatic Hitchhikes, read our
Brochure
Site Assessments
Conducting a site assessment is one of the first steps of an aquatic weed management project.  Site assessments identify what species of plants are present and focus on things that are necessary for project planning, such as determining access points and water uses.  Examples of water uses are irrigation, recreation (swimming, fishing, etc.) and municipal water source.  If noxious aquatic weeds are present, they will be documented, and both the size and severity of the infestation will be estimated.  Aquatic weeds that float on the surface of water (e.g., Water Hyacinth and Giant Salvinia) and aquatic weeds that grow up and out of the water (referred to as “immersed” or “emergent plants”, such as Alligatorweed and Water Primrose) are easy to observe. The size of the infestation is typically estimated by visual reconnaissance, or by using a handheld GPS device.  GIS software is also a good tool for estimating size and describing the site. Aquatic weeds that are rooted in the bottom (referred to as “submersed” plants, such as Hydrilla and Watermilfoil) are not as easy to observe.  Estimating the size and severity of a submersed aquatic weed infestation is difficult.  Turbid or tannic water conditions makes this task even more challenging, and the use of specialized equipment is often required.
Aquatic Vegetation Surveys
Aquatic vegetation surveys, similar to site assessments, document noxious aquatic weeds (if present at the site).  Think of an aquatic vegetation survey as an inventory of plants.  The survey identifies what plants are present and where those plants are growing. Depending on the goal, the survey may inventory floating plants, emersed plants, and submersed plants.  Regardless of scope, the survey is a snapshot and can serve as a baseline.  Surveys provide critical information to environmental managers.  Information which is used for aquatic weed project planning and is also used to track project progress.
Aquatic vegetation surveys are conducted annually for many of the program’s Hydrilla management projects.  The program has adopted a survey methodology which involves the collection of two sets of data:  physical sampling and remote sensing. Physical sampling is conducting with a metal rake.  The rake collects vegetation from the bottom.  Sample points are pre-determined (not random).  Vegetation collected via physical sampling allows the surveyor to observe and record the species of plant(s) present.  Remote sensing is conducted with a recording fathometer device, which leverages SONAR technology and GPS technology. The device is mounted on a boat. The operator tracks the shoreline and typically includes the entire littoral zone.  Track lines are adjusted based on site conditions.  The two sets of data are analyzed. This methodology generates maps that show what species of aquatic vegetation was detected, where the vegetation occurs and the relative density.  The outcome of the survey also estimates the total area occupied by each species of vegetation.
Aquatic vegetation survey reports are linked in the tables below, separated by river basin.
Aquatic Vegetation Survey Reports
Little Tennessee River Basin
Body of Water
2020
2021
2022
2023
2024
Lake Santeetlah
Neuse River Basin
Body of Water
2020
2021
2022
2023
2024
Buckhorn Lake
Orange County
Cape Fear River Basin
Body of Water
2020
2021
2022
2023
2024
Cane Creek
Lake Reidsville and Lake Hunt
Lake Rim
Umstead State Park
White Lake
Shearon-Harris Lake
Mintz Pond
Yadkin-Pee Dee River Basin
Body of Water
2020
2021
2022
2023
2024
Lake Tillery
Badin Lake Sub-impoundments and Falls Reservoir
Tar-Pamlico River Basin
Body of Water
2020
2021
2022
2023
2024
Lake Devin
Tar River Reservoir
Roanoke River Basin
Body of Water
2020
2021
2022
2023
2024
Lake Gaston
Roanoke River Rapids
Lumber River Basin
Body of Water
2020
2021
2022
2023
2024
Lake Waccamaw
Comprehensive List of Projects and Project Costs
2025 Aquatic Weed Control Work Plan
Management activity database
Large-Scale Projects
Eno River
Gapway Swamp
Lake Waccamaw
Lake Norman
Lake Tillery
If you need help with controlling or managing aquatic plants, please contact:
Contact name
Contact information
Rob Emens, Aquatic Weed Program Manager
(919) 707-9012
Rob.emens@deq.nc.gov
Andrew Gay, Aquatic Weed Specialist
(919) 707-9020
Andrew.gay@deq.nc.gov
The following links will provide more information about the program, aquatic vegetation identification, and aquatic weed management:
Local Resources
North Carolina Cooperative Extension Service
North Carolina Invasive Plant Council
North Carolina State University- Aquatic Plant Management
North Carolina State University- Integrated Pest Management
2019 North Carolina Agricultural Chemicals Manual: Chemical Weed Control
North Carolina's Aquatic Nuisance Species Management Plan
, Updated October 1, 2015
Aquatic Plant ID and Management Guides
Biology and Control of Aquatic Weeds
Univ. of Florida IFAS Extension
Habitattitude
Aquatic Plant Field Guide
Aquatic & wetland plants of SC
AquaPlant
Aquatic Plant Management Societies
The Aquatic Plant Management Society, Inc.
South Carolina Aquatic Plant Management Society
Weed Science Society of North Carolina
National Invasive Species Council
Mid-Atlantic Panel on Aquatic Invasive Species
Federal Interagency Committee for the Management of Noxious and Exotic Weeds
Historic data from the Aquatic Weed Program can be found here:
Surveys
Body of Water
River Basin
2019
Shearon Harris Reservoir
Cape Fear
Badin Lake Sub-impoundments and Falls Reservoir
Yadkin- Pee Dee
Workplans
Coming soon
Related Content
Aquatic Weed Control Act of 1991
North Carolina Aquatic Nuisance Species Management Plan
Stop Aquatic Hitchhikers
Weed Regulatory Services
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This page was last modified on 01/16/2026