Prineville reports near-year of water stored as ASR pump upgrade boosts capacity

Director provided an update on Prineville's Aquifer Storage and Recovery (ASR) operations, saying the program is now on its seventh cycle and that the city has stored roughly 600,000,000 "so we were hoping to store about a year's worth, and we're about there." He said the ASR system moves treated water up the hill in winter and reverses flow in summer so wells on the valley floor are not pumped during peak demand.

The director attributed recent gains to a pump upgrade: "our new pump is is 450 horsepower. The old 1 was was 250," he said, explaining the increased horsepower pushed more water into the aquifer during injection cycles. Staff noted that when the pump was turned off, aquifer levels dropped back down and matched an earlier cycle, so the city will monitor the conclusion of cycle seven to see whether total storage has plateaued.

City staff framed the ASR system as a redundancy that allows the city to inject and withdraw from different wells as needed; the director added that if injections push the aquifer too far outward rather than upward, the city may need to shift withdrawal wells farther downstream to recover stored water. The director said the ASR story has drawn recent media attention and that staff will present findings at regional water-summit discussions.

The commission heard staff's request to continue monitoring cycle 7 data before making operational changes. The next procedural step is staff review of final cycle-seven results and follow-up reporting to council and the commission.