Agenda - 02-16-2021; 4-b - OWASA Annual Update Presentation

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Information on OWASA's Long-Range Water Supply Plan 14 January 29,2021 Page 8 4. Identify Alternatives for Reducing Water Supply Risks What are supply and demand management strategies? Supply-side options are strategies which increase the total reliable yield of our water supply system. In other words, they would raise the blue line shown in Figure 3. Demand-side management options are strategies which reduce raw water demands from existing and/or new development or lower the black line shown in Figure 3. How did OWASA identify which supplies and demand management strategies to evaluate? We met with local government planners and UNC, obtained input from Board members and neighboring utilities, and reviewed existing plans and documents to identify potential alternatives to meet our long-term needs through 2070. Through this process we selected demand management(increased water efficiency and conservation) and reuse strategies, as well as supply strategies to evaluate in further detail. 5. Evaluate Alternatives What supplies and demand management strategies did OWASA consider? OWASA evaluated nine supply alternatives which can be grouped into three major categories: 1. Jordan Lake alternatives (4 alternatives) 2. Quarry Reservoir(2 alternatives) 3. Indirect and direct potable reuse (3 alternatives) Each of these alternatives are summarized below along with OWASA staff recommendation for next steps in its consideration. The four Jordan Lake alternatives are summarized below: • Alternative 1 —Full Partner in New Intake and Water Treatment Plant (WTP) on Western Side of Jordan Lake—OWASA would partner with the Western Intake Partners (currently City of Durham, Town of Pittsboro, and Chatham County) on a new water supply intake, water treatment plant, and major transmission infrastructure on the western side of Jordan Lake. o Recommendation: Continue to evaluate alternative • Alternative 2—Continue with Mutual Aid Agreements—This is our existing baseline condition. Under this alternative, OWASA would access its Jordan Lake allocation using its mutual aid agreements with the Town of Cary and City of Durham. This alternative does not guarantee access to our allocation. o Recommendation: Baseline condition; maintain for the time being • Alternative 3—Develop New Agreement with Towns of Cary and Apex to Guarantee Access to Jordan Lake Water—The Towns of Cary and Apex jointly own the only water supply intake on Jordan Lake and share a water treatment plant. Under this alternative, OWASA would develop a new agreement with the Towns to guarantee withdrawal and treatment of a certain amount of water on an annual basis.