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

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Information on OWASA's Long-Range Water Supply Plan 15 January 29,2021 Page 9 o Recommendation: Alternative not feasible at this time • Alternative 4—Develop Agreement with Western Intake Partners to Guarantee Access to Jordan Lake Water—OWASA would develop an agreement with the Western Intake Partners to guarantee capacity in the proposed intake and water treatment plant on the western side of Jordan Lake. This agreement would guarantee a certain amount of water on an annual basis in return for payment from OWASA. o Recommendation: Continue to evaluate Two Quarry Reservoir supply alternatives were evaluated: • Alternative 5—Shallow Quarry—access with existing pumping infrastructure. This is the alternative selected in the 2010 LRWSP and considered the future baseline alternative. The yield from the expanded Quarry Reservoir is included on Figure 3. o Recommendation: Baseline condition; included in our capital improvements program • Alternative 6—Deep Quarry—deeper quarry depths would be accessed with new pumping infrastructure when the expanded Quarry Reservoir is online. o Recommendation: Eliminate from further consideration due to high capital cost and does not address vulnerability of small Cane Creek Reservoir watershed OWASA evaluated the use of reclaimed water(highly treated wastewater) for drinking (potable) water uses. As used in our LRWSP, indirect potable reuse involves mixing reclaimed water in an environmental buffer prior to being treated at the Jones Ferry Road WTP; direct potable reuse involves further treating the reclaimed water at the Mason Farm Wastewater Treatment Plant (WWTP) and then pumping it directly into our water distribution system. Potable reuse alternatives evaluated are summarized below: • Alternative 7a: Indirect Potable Reuse with Pretreatment Mixing Basin near Quarry Reservoir—This alternative was developed to meet the requirements of a general statute which allows for indirect potable reuse mixed at specified ratios with another source water in an engineered pretreatment mixing basin. Reclaimed water from the Mason Farm WWTP would be pumped to a new pretreatment mixing basin near the Quarry Reservoir. This water would be mixed with water from Cane Creek Reservoir in accordance with the statute. o Recommendation: Eliminate from further evaluation since very high capital and life cycle costs • Alternative 7b: Indirect Potable Reuse with Return to Quarry Reservoir—This alternative is similar to Alternative 7a,but water from the Mason Farm WWTP would be pumped to the Quarry Reservoir rather than a new pretreatment mixing basin. o Recommendation: Eliminate from further evaluation since very high capital and life cycle costs • Alternative 8: Indirect Potable Reuse with Return to University Lake—Reclaimed water from the Mason Farm WWTP is returned to University Lake.