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ORANGE COUNTY I 11 C �o� ��ill �� Department of Environment, .A griculture, Parks Recreation To: Commission for the Environment From: Tom Davis, Water Resources Coordinator Re: Eno River Hydrilla Management Pilot Study Update Date: August 3, 2016 Recently, the Eno River Hydrilla Management Task Force (Task Force) met to discuss the status of the hydrilla management pilot study activities in the Eno. Quoting the update from SePro, the firm under contract to conduct the Eno River herbicide (Sonar) treatment: Overall, the Sonar program appears to have provided full control of early -stage hydrilla growth present at time of application start. Representative photos of hydrilla condition near the start of the 2016 treatment program and at 1 month into the treatment (June 10) are at the end of this update. NCSU staff indicated that recent surveys have not been able to detect hydrilla in the treatment zone. Regarding nontarget plant effects, riffleweed appears healthy and unaffected by management activities and water willow stress is almost non - detectable. The minimal willow stress contrasts with the relatively strong chlorosis noted in mid - summer of a hot and dry 2015 when a single injector was used versus the two used this season. Thorough late July, flows in the Eno have been above the long -term mean, resulting in above - expected usage of herbicide. As a result, additional funds are needed to continue the management effort through the remainder of the growing season. Several of the funding partners involved with this project, including Orange County, have pledged funds to continue the hydrilla management project. Additional discussion focused on the next phase of this project. Consensus seemed to be emerging that the goal of the next phase of this project should be to reduce the presence of hydrilla throughout the main stem of the Eno to non - nuisance levels, and once when that is achieved the Task Force can then work to determine if hydrilla is present in other areas of the watershed at nuisance levels. This goal would build on the pilot study, as well as ongoing hydrilla management activities in Corporation Lake, Lake Orange, West Fork of the Eno River Reservoir, and Compton's Pond. This would also likely involve herbicide addition at more than one location in the main stem of the Eno. SePro is interested in working with the Task Force to develop a wider -scale management plan for the Eno this fall. M4,11 °ll„JI) °111.., and Pa'll, I Illl„JII ° I RESOURCES S IlMVllSllON Orange County Department of Environment, Agriculture, Parks & Recreation PO Box 8181, Hillsborough, NC 27278 Phone: (919) 245 -2510 Fax: (919) 644 -3351