Agenda 11-02-23; 4-a - Resolution Endorsing Consensus Principles II for Revised Falls Lake Rules

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=22 management is essential to maintaining designated uses. The critical management objective for Falls Lake must be to mitigate impacts from existing activities in the watershed and to design and manage land use changes while continuing to maintain and improve water quality in Falls Lake. Without reasonable, balanced, and economically supportable actions, the risk of increasing eutrophication, degradation of water quality, and adverse impacts to designated uses is a real possibility. Regulatory and Statutory Requirements for Falls Lake, the UNRBA Response, and the Limitations of the Current Management Approach Statutory Requirements and the Rules In 2005, the NC General Assembly passed Senate Bill 981 requiring the NC EMC to develop a nutrient management strategy for Falls Lake. The bill also directed the Commission to "consider the cost of the proposed measures in relation to the effectiveness of the measures. These measures could include, but are not limited to, buffers, erosion and sedimentation control requirements, post- construction stormwater management, agricultural nutrient reduction measures,the addition of nutrient removal treatment processes to point source permitted wastewater treatment plants, the removal of point source discharging wastewater treatments through regionalization and conversion to non-discharge treatment technologies, and any other measures that the Commission determines to be necessary to meet the nutrient reduction goals." In 2009, Senate Bill 1020 was passed to provide credit for early implementation of practices installed before the Rules were adopted. This bill also delayed adoption of the Rules from July 1, 2009, to January 15, 2011, and required that "stormwater management programs to reduce nutrient loading from new development be implemented no later than 30 months after the Rules become effective." Additional measures listed for consideration in the nutrient management strategy were included in this bill: "measures to address nutrient inputs from on-site wastewater treatment systems, control of atmospheric deposition, allowing the sale and purchase of nutrient offsets, and allowing trading of nutrient loading allocations and credits for nutrient reductions." The bill also specified design standards for sedimentation and erosion control for land-disturbing activities and stated that this section of the bill would not be delayed and would have a start date of January 1, 2010. These requirements were addressed in the Falls Lake Rules. To support rules development, DWR used predictive modeling of the watershed and the reservoir to develop the Falls Lake Rules, which set two stages of nutrient reduction requirements for the lake. In January 2011, the Falls Lake Rules were adopted by the EMC. The Rules state: The objective of Stage I is to, at minimum, achieve and maintain nutrient-related water quality standards[chlorophyll-a criterion]in the Lower Falls Reservoir[downstream of Highway 50]as soon as possible but no later than January 15, 2021, and to improve water quality in the Upper Falls Reservoir[upstream of Highway 50]. The objective of Stage II is to achieve and maintain nutrient-related water quality standards throughout Falls Reservoir. This is estimated to require a reduction of 40 and 77 percent in average annual mass loads of nitrogen and phosphorus respectively, delivered from the sources named in Item (6) in the Upper Falls Watershed from a baseline of 2006. The resulting Stage II allowable loads to Falls Reservoir from the watersheds of Ellerbe Creek, Eno River, Little River, Flat River, and Knap of Reeds Creek shall be 658,000 pounds of nitrogen per year and 35,000 pounds of phosphorus per year. (15A NCAC 02B.0275) However, both the monitoring and modeling were developed on a compressed time schedule with limited data. As a result, there is significant uncertainty in the nutrient load reduction targets and 3