Mount Pleasant's new water tank is ready to bid; council debates aging pipeline, valves and hydro options

Mount Pleasant staff told the March 24 work session that plans are complete and the new upper water tank is engineered and ready to be bid, but staff warned the pipeline running from the treatment campus (the "acid house" area) down the canyon is old and may not hold the pressure the new tank would introduce.

A staff member summarized the concern plainly: "That pipe has me nervous. It's thin, and it's old. It's 30 to 40 years old." The risk is that pressurizing the upper tank could place stress on brittle, aged pipe and risk failure. Staff outlined short-term operational mitigations: install pressure-reducing valves (PRVs) and SCADA-controlled valving on the new tank outlets to release flow when downstream pressure thresholds are exceeded, limiting stress on the old line.

Council members asked about alternative approaches, including placing hydropower units ("hydros") on the line to both reduce upstream pressure and generate electricity. Staff cautioned hydros would run inconsistently because generation would be driven by downstream demand, and they advised a cost-effectiveness study before pursuing hydropower. Members discussed funding pathways: using contingency dollars from the treatment-plant budget to purchase PRVs now, and applying for rural-development or USDA loans and grants to support pipeline replacement where possible.

Staff said bidding for the tank will begin in the next month or two and estimated construction of the tank at roughly six months. The city will pursue interim valve solutions to enable limited tank use without fully pressurizing the old pipeline while seeking funding to replace the line and resolve long-term risk.

Note on acronyms: the transcript referenced CIB as a funding source; the meeting did not expand the acronym in the record.