Agenda - 11-10-2015 - 6 - Eno River Hydrilla Management Pilot Study Update

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2 study (Attachment B). Details were provided on the problem, the results of an Environmental Assessment for the proposed project, and the selection of a contractor to apply and monitor the herbicide in the Eno. Additional public outreach efforts were conducted throughout the watershed (Attachment C). Pilot study herbicide treatments in the Eno River began in late May 2015. Low stream flows over the summer aided in maintaining a consistent concentration of fluridone, the active ingredient in the herbicide, throughout the treatment zone, from Lawrence Road east of Hillsborough downstream to Roxboro Road in Durham. Monitoring of the concentration of fluridone in various locations along the river occurred throughout the duration of the study. Monitoring of native vegetation, snails, crayfish and fish above and within the treatment zone was also conducted before and during the hydrilla treatment. Bleaching of hydrilla was observed after just one week of herbicide treatments. Within four weeks, there was notable reduction in the density of hydrilla in the treatment zone. Further herbicide treatment resulted in dramatic differences in hydrilla density between the treatment area and the untreated area upstream. Nearly-complete removal of visible hydrilla vegetation was reported at locations within the area of treatment (Attachment D). The Eno Hydrilla Management Task Force will continue to evaluate data from surveys of the Eno River ecosystem both within and above the treatment zone. Native vegetation is responding positively. It is anticipated that the results of the first year of the pilot study will be overwhelmingly positive, and that the Task Force will proceed with the second year of treatment. Over the winter months, the Task Force will consider using a lower concentration of fluridone, starting the injection process earlier in the growing season, and adding a second injection location in order to further minimize the apparent impact to native plants. Following completion of the full two-year pilot study, the Task Force will begin to discuss long-term objectives for the management of hydrilla throughout the Eno River watershed. Lastly, the County recently completed a contract with the NC Division of Water Resources for the addition of sterile grass carp to Lake Orange, which is infested with hydrilla. Grass carp are routinely used to help control hydrilla in lakes and reservoirs. FINANCIAL IMPACT: The total cost of this two-year pilot study is $150,000, with the NC Division of Water Resources providing half of the funding. DEAPR has agreed to provide $10,716 for the pilot study. Additional hydrilla management, especially if the treatment area is increased, could require some level of financial commitment on the part of the County after the pilot study concludes in FY2015-2016. SOCIAL JUSTICE IMPACT: The following Orange County Social Justice Goal is applicable to this agenda item: • GOAL: ESTABLISH SUSTAINABLE AND EQUITABLE LAND-USE AND ENVIRONMENTAL POLICIES The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, policies, and decisions. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies.