Keller Associates briefed the St. Helens city council on a reservoir siting study on Dec. 17, describing a multi‑phase evaluation that narrowed 11 initial locations to four finalists and ultimately recommended Site 2 based on cost, constructability and system connection length.

Consultant Alexis said the selection considered hydraulic pressure zones, pipeline connections, overflow/drain routing and geotechnical constraints. Field borings and lab testing showed basalt at Site 2 — a geologic condition the team described as favorable for building a large water tank — while Site 4 had more challenging geologic conditions and Site 3 ranked lower on constructability concerns.

The consultants also reported environmental and permitting findings: Sites 2 and 4 contain documented wetlands and the team recommended habitat assessments and coordination with permitting agencies (Army Corps, Department of State Lands) as mitigation steps. The consultants stated they had found no ‘‘fatal flaws’’ among the four alternatives but noted Sites 1 and 4 present more hydraulic transmission issues requiring upsized pipelines (recommended 24‑inch transmission lines in some alignments).

Councilors acknowledged those tradeoffs. One councilor said the city’s history of building in wetlands raised concern about mitigation, traffic impacts from construction trucks in residential areas and the potential for prolonged permitting timelines. Another councilor emphasized seismic and structural stability, supporting Site 2’s higher ranking because it reduces liquefaction and foundation risks.

Keller Associates outlined next steps: finalize the siting study, present the final report to council in January, begin property‑acquisition discussions for the preferred site and work in parallel on funding and design. Consultants and staff said additional geotechnical and permitting work will be required before any property acquisition or formal council land‑use decisions.

The presentation did not result in a binding decision; councilors directed staff to return with the final study and funding analysis in January for further direction.