Eno River Hydrilla Management Project
Photo below shows Pleasant Green access site during the height of the Hydrilla infestation (2014)
The content on this page has been provided by the
Eno River Hydrilla Management Task Force
The purpose of this page is to serve as a centralized location for information specific to the Eno River Hydrilla Project. The information ranges broadly from very general documents and updates to highly technical reports.
Beginning in 2020 Eno River project information will transition to a new website. Thank you to NC-IPC for providing a home for this project on their website for all of these years! Going forward the NC Aquatic Weed Control Program website will become the primary site for the most up to date information. Click here.
This webpage will not be deleted and serve primarily as an archive.
Beginning in 2020 Eno River project information will transition to a new website. Thank you to NC-IPC for providing a home for this project on their website for all of these years! Going forward the NC Aquatic Weed Control Program website will become the primary site for the most up to date information. Click here.
This webpage will not be deleted and serve primarily as an archive.
Managing Hydrilla with herbicide in the main stem of the Eno River
2019 herbicide treatment summary:
An herbicide treatment (fluridone) started on June 17th and continued through August 15th. The herbicide was metered into the river using an injector system, which was routinely readjusted to match the flow of the water. The section of the Eno that was treated is defined by the Lake Ben Johnson dam in Hillsborough and downstream to Lawrence Road bridge in Hillsborough. This is a shorter stretch of the river compared to previous treatment targets.
No Hydrilla was observed/reported within the treatment area in 2019.
2018 herbicide treatment summary:
An herbicide treatment started on May 24th and continued through August 15th. This was essentially a repeat of the treatment that was done in 2017. The section of the Eno that was treated is defined by the Lake Ben Johnson dam in Hillsborough and downstream to the Roxboro Street bridge in Durham. The herbicide (fluridone) was applied by two injection systems. Each system precisely metered the herbicide product and was routinely adjusted to match the flow of the river. Monitoring efforts occurred throughout the season; no negative impacts to the environment were observed/reported. Water samples pulled from the treatment area on August 28th were analyzed for herbicide levels and all samples were found to have <1 part per billion (ug/L) fluridone. This is equivalent to 'no detect' levels.
No Hydrilla was observed/reported within the treatment area in 2018.
2017 herbicide treatment summary:
An herbicide treatment started on June 30th and continued through August 15th. Since the first two years of managing Hydrilla with herbicide had been very successful the ERHM Task Force decided to expand the treatment area in 2017. The area that was treated in 2015-2016 was included in the treatment. The change in 2017 was that the treatment area was expanded upstream to just below the Lake Ben Johnson dam. Similar to 2016, two injection systems were used to meter herbicide into the river.
2016 herbicide treatment summary:
The treatment area and herbicide product remained consistent with the 2015 treatment. The herbicide product was metered into the river using two injector systems. The addition of a second injector system (located approximately midway through the treatment area) allowed for better control of the target concentration and allowed for a reduction in the total quantity of herbicide needed. The herbicide treatment did not prohibit, or impact in any way, recreational activities such as wading and swimming nor did it impact fishing or fish consumption. The treated water remained fit for consumption by animals (livestock, domestic pets, wildlife, etc.).
2015 herbicide treatment summary:
An aquatic-use herbicide was used to treat a section of the Eno. A liquid formulation of fluridone was metered into the water at a single location. The treatment began in June and ended in August. The treatment effectively controlled the growth of Hydrilla throughout the ~16 mile long stretch. The treatment area defined as the Lawrence Road bridge (just downstream of Hillsborough) and down to N. Roxboro Street (north of Durham).
An herbicide treatment (fluridone) started on June 17th and continued through August 15th. The herbicide was metered into the river using an injector system, which was routinely readjusted to match the flow of the water. The section of the Eno that was treated is defined by the Lake Ben Johnson dam in Hillsborough and downstream to Lawrence Road bridge in Hillsborough. This is a shorter stretch of the river compared to previous treatment targets.
No Hydrilla was observed/reported within the treatment area in 2019.
2018 herbicide treatment summary:
An herbicide treatment started on May 24th and continued through August 15th. This was essentially a repeat of the treatment that was done in 2017. The section of the Eno that was treated is defined by the Lake Ben Johnson dam in Hillsborough and downstream to the Roxboro Street bridge in Durham. The herbicide (fluridone) was applied by two injection systems. Each system precisely metered the herbicide product and was routinely adjusted to match the flow of the river. Monitoring efforts occurred throughout the season; no negative impacts to the environment were observed/reported. Water samples pulled from the treatment area on August 28th were analyzed for herbicide levels and all samples were found to have <1 part per billion (ug/L) fluridone. This is equivalent to 'no detect' levels.
No Hydrilla was observed/reported within the treatment area in 2018.
2017 herbicide treatment summary:
An herbicide treatment started on June 30th and continued through August 15th. Since the first two years of managing Hydrilla with herbicide had been very successful the ERHM Task Force decided to expand the treatment area in 2017. The area that was treated in 2015-2016 was included in the treatment. The change in 2017 was that the treatment area was expanded upstream to just below the Lake Ben Johnson dam. Similar to 2016, two injection systems were used to meter herbicide into the river.
2016 herbicide treatment summary:
The treatment area and herbicide product remained consistent with the 2015 treatment. The herbicide product was metered into the river using two injector systems. The addition of a second injector system (located approximately midway through the treatment area) allowed for better control of the target concentration and allowed for a reduction in the total quantity of herbicide needed. The herbicide treatment did not prohibit, or impact in any way, recreational activities such as wading and swimming nor did it impact fishing or fish consumption. The treated water remained fit for consumption by animals (livestock, domestic pets, wildlife, etc.).
2015 herbicide treatment summary:
An aquatic-use herbicide was used to treat a section of the Eno. A liquid formulation of fluridone was metered into the water at a single location. The treatment began in June and ended in August. The treatment effectively controlled the growth of Hydrilla throughout the ~16 mile long stretch. The treatment area defined as the Lawrence Road bridge (just downstream of Hillsborough) and down to N. Roxboro Street (north of Durham).
Brief description of the Eno River and
history of Hydrilla within the watershed
The Eno River is a relatively shallow, swift flowing, Piedmont stream originating in northwest Orange County. It forms at the confluence of the West Fork Eno River and the East Fork Eno River and flows eastward through Durham County where it joins the Flat River to form the headwaters of the Falls Lake Reservoir. From its origin to Falls Lake the Eno flows approximately 28 miles and encompasses an approximately 150 square mile watershed area.
Previous to 2005 the only known Hydrilla infestation within the Eno watershed was Lake Orange. Lake Orange was confirmed as a Hydrilla site in 1992. The lake was stocked with triploid grass carp in 1994 and also in 1998 for the purpose of removing the invasive plant. Hydrilla was thought to be eradicated from Lake Orange by 2005.
In 2005 Hydrilla was observed growing in a section of river within the Eno River State Park boundaries. Since 2005 Hydrilla has been reported in several locations along the the Eno River Between Hillsborough and Roxboro Road in Durham. Including many of it's impoundments; specifically, Corporation Lake, the West Fork Eno Reservoir, Lake Orange and Comptons Pond.
Previous to 2005 the only known Hydrilla infestation within the Eno watershed was Lake Orange. Lake Orange was confirmed as a Hydrilla site in 1992. The lake was stocked with triploid grass carp in 1994 and also in 1998 for the purpose of removing the invasive plant. Hydrilla was thought to be eradicated from Lake Orange by 2005.
In 2005 Hydrilla was observed growing in a section of river within the Eno River State Park boundaries. Since 2005 Hydrilla has been reported in several locations along the the Eno River Between Hillsborough and Roxboro Road in Durham. Including many of it's impoundments; specifically, Corporation Lake, the West Fork Eno Reservoir, Lake Orange and Comptons Pond.
Eno River Hydrilla Management Task ForceThe Eno River Hydrilla Management Task Force (ERHM TF) is a partnership of government agencies, academia and non-profit organizations (see list to right). The partnership is composed of aquatic vegetation management experts, environmental managers, stakeholders and environmental stewards. The ERHM TF serves as a project oversight group and is composed of four committees (Outreach, Research and Monitoring, Funding, and Public Health). The idea of assembling a task force emerged in November of 2012 when several agency representatives met to discuss the continuing and worsening spread of the invasive weed Hydrilla within the Eno River. The ERHM TF began to coalesce to include the many partners now represented and has met roughly twice per year since 2013. Please direct any questions or comments you have about the Eno River Hydrilla Management Task Force: Rob Emens rob.emens@ncdenr.gov |
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What can be done to slow the spread of Hydrilla?
- Educate yourself and others on Hydrilla
- Report sightings of Hydrilla to Eno River State Park staff
- Don't be a vector.... Clean, Drain, Dry is a great managment practice, see below:
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Hydrilla (Hydrilla verticillata )
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Management Strategies
Herbicide applications in summer.
Selected herbicides are: • Approved by the EPA for aquatic sites • Pet safe / non-toxic to fish • Do not restrict recreational activity at application rates Citizens and wildlife/environmental managers play a critical role in preventing, detecting and reporting new infestations. If you have found a plant you believe could be Hydrilla please contact Rob Emens (NC Division of Water Resources). rob.emens@ncdenr.gov 919-707-9012 |
Point of Contact:Eno River State Park
919-383-1686 eno.river@ncparks.gov 
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Document Links
Other Documents
(RESEARCH - NEWSPAPER ARTICLES - SURVEY REPORTS)
