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

Browse Search

�FV 13 • Forested areas are important to the ecological health of the watershed and should be protected. Natural areas, including forests, cycle nutrients and provide important nutrients to waters that sustain aquatic life. • North Carolina is the only state that limits chlorophyll-a everywhere in a waterbody using instantaneous measurements. A summary of other state's approaches to chlorophyll-a standards is summarized in the April 7, 2020 PFC meeting presentation (slides 57 to 68) • Several scenarios were evaluated with the UNRBA watershed and lake models. None of the scenarios were able to achieve delivered nutrient loading to Falls Lake that would meet Stage II of the Falls Lake Nutrient Management Strategy nor were any of the scenarios able to meet the chlorophyll-a standard everywhere in Falls Lake. Even a scenario that converts all land to forest and wetlands and removes all watershed-scale human inputs was not able to achieve these goals and standards (rates of atmospheric deposition were not changed for this scenario). • Lake modeling indicates that an additional 50 percent reduction in total nitrogen delivered to Falls Lake would be needed to achieve the chlorophyll-a water quality standard 90 percent of the time. Achieving this level of additional reduction would require treating runoff from natural areas like forests. An evaluation of a pump-and-treat approach using an algal harvesting system studied by the City of Durham indicates that at least 138 systems would be needed to meet this level of nitrogen loading. However,there is not sufficient water consistently available in the stream network to run this many systems. While these systems should remain an option to consider as part of the revised nutrient management strategy, constraints like cost and land availability will limit widespread application. • Achieving measurable load reductions to Falls Lake will require a systems approach directed at realistic and incremental change in the nutrient balance. The Stage I Interim Alternative Implementation Approach (IATA) approved by the EMC provides a useful framework for the revised nutrient management strategy. • Stakeholder participation in the process is critical to developing a successful strategy. • A watershed approach for non-point sources provides nutrient management for all waters draining to Falls Lake, including upstream water supply impoundments. Recommendations for a Comprehensive Approach to Nutrient Management Proposed by the UNRBA The UNRBA has been working with other watershed stakeholders to study the Falls Lake watershed since 2011. These collaborative efforts have included discussions with internal and external stakeholders who recommend that the revised nutrient management strategy incorporate the fundamental principles of IAIA including using an investment-based,joint-compliance framework on the implementation of projects and activities beneficial to water quality across the watershed. Based on the extensive work conducted by the UNRBA,the successes of the IAIA Program, and the feedback from external and internal stakeholders,the UNRBA Path Forward Committee (PFC) developed a list of foundational principles for a revised nutrient management strategy. It is anticipated that the jurisdictional governing boards or commissions of the UNRBA will sign a document stating their commitment to a list of foundational principles submitted as part of the UNRBA's recommendations. Below is a brief description of some of these principles which are further described later in this document: Embrace a systems approach focusing on right-sized solutions. Progressive management of this watershed will require looking beyond individual pipes and parcels of land. Nutrient load reductions will be incremental as project identification and implementation are very challenging. A more comprehensive approach that considers the atmosphere, soils, surface water, groundwater, and iv