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Newport provides update on Big Creek dam replacement, ongoing seepage repairs and funding work
Summary
City staff briefed the council on the long-running Big Creek dam safety issue, current 30% design for a roller‑compacted concrete replacement, state‑funded design work, a new funding study by Stantec and ongoing seepage repairs at Dam No. 2.
City Manager Nina Vetter and City Engineer Chris Beatty briefed the Newport City Council on the status of the Big Creek dam replacement program, describing both long‑term replacement planning and near‑term seepage repairs at Big Creek Dam No. 2.
Vetter summarized the history: the city’s two earthen Big Creek dams (one built in 1951 and the other in 1968) were identified in 2011 as having soils at the dam base that are subject to liquefaction in a seismic event. "That means in a seismic event, [it] would likely create significant damage and potential loss of life," she said. Engineers subsequently evaluated alternatives and the city moved forward with design for a roller‑compacted concrete dam; the design is currently at about 30 percent and the design work is funded by state dollars.
The city has engaged the firm Stantec to prepare a funding strategy and implementation plan; Vetter said the funding work is expected to take about four to six months and is meant to outline possible mixes of local, state and federal funding and an implementation timeline.
Beatty described an active seepage issue at Big Creek Dam No. 2 involving a 90‑inch corrugated metal spillway/underdrain that has corroded in places. He said OWRD (Oregon Water Resources Department) inspections in 2018 and 2019 identified corrosion and that inspections in July 2024 still showed seepage. "Internal erosion, if left unmitigated, could result in catastrophic failure of the dam," Beatty said. The city contracted Jacobs Engineering and James Fowler Company for emergency repairs in 2022 that included grouting and installing hydraulic pressure relief drains; those repairs reduced seepage but further analysis and likely lining of the pipe remain under study.
Beatty said Jacobs is preparing an alternatives analysis that will evaluate measures such as lining the 90‑inch pipe and investigating the 30‑inch underdrain for potential issues.
Councilors asked about potential changes in storage volume if a concrete dam is built. The presenters said some replacement types could impound more water, but storage requirements must be balanced with in‑stream flow requirements being discussed with the Oregon Department of Fish and Wildlife; those flows will influence ultimate storage needs and project sizing.
Vetter said HDR Engineering will present the 30 percent design at a June 16 work session and the council will receive follow‑up briefings on seepage remediation progress, the alternatives analysis and the Stantec funding plan.
