Prescott study session spotlights failing SR 89 effluent pipeline, three 15% design alternatives for roadway upgrades

Prescott City Council held a study session on Aug. 26, 2025, to review 15% design concept plans for replacement of a failing 24‑inch effluent pipeline and potential improvements to State Route 89, staff said.

Gwen Roich, public works director for the City of Prescott, said the urgency is the pipe: “the number 1 priority is the pipe.” Roich told the council the existing 24‑inch effluent line “has had more than 8 failures in the last 2 and a half years,” and staff moved the repair up in the five‑year capital plan because repeated breaks have caused road closures and public inconvenience.

The council was presented with three 15% design alternatives prepared by Kimley‑Horn and partners and a staff summary of public comments collected during an ongoing 60‑day comment period. The alternatives are: Alternative 3b (a full corridor five‑lane widening, budgetary estimate $36,700,000), Alternative 5b (a hybrid five‑lane/ four‑lane with barrier through the narrow section, estimate $35,500,000), and Alternative 2b (a non‑widening alternative focusing on safety improvements, estimate $25,200,000). Andrew Baird of Kimley‑Horn said, “we generated a full 15% concept plan for all 3 alternatives.”

Why it matters: the pipe carries treated effluent, and repeated failures have prompted the city to consider replacing the pipe and, because construction will remove most of the existing roadway, whether to widen or otherwise upgrade SR 89 at the same time. Roich said multiple pipes will be installed in the corridor — three 24‑inch pipes in total — and that “when we do that, we’re gonna…