Engineers recommend coastal analysis as next step on damaged breakwater

Engineers who inspected Oak Harbor’s breakwater recommended a focused coastal analysis to determine how to repair or reconfigure the structure after divers and engineers found worsening damage during recent low tides.

The commission heard that a team from Moffett Nichols performed dive inspections and in-person testing to compare recent conditions with prior surveys. Bill, an engineer with Moffett Nichols, told commissioners the breakwater’s sawtooth configuration is uncommon and that the “attenuation effect” of that design cannot be reliably estimated without a coastal analysis that models wave transmission and wave attenuation for the site. He said the firm would provide an updated fee estimate for that analysis this week.

Why it matters: commissioners and staff said the study is needed so council members can see a definitive cost and options before an anticipated vote tied to the city’s B&O tax discussion. Without the analysis, staff and engineers said, they cannot say whether the structure can be modified (for example, shortening panel depth or lowering wall height) or whether it must be replaced.

Engineers and staff reported new damage revealed by an “astronomically low” tide event. Elise Henry, the new harbor master, said patios numbered 1 through 8 at the north end were exposed during a minus-4-foot tide and showed warping and marine growth; those patios sat about 1.6 feet above mean surface and were grounding during the low tide, she said. Inspectors identified additional patio wall damage along the walkway and noted that South F dock did not show new damage beyond previously known issues.

The consultants outlined several options that a coastal analysis would clarify: removing a portion of the patios (a proposed 25% reduction was discussed), reducing the submerged panel depth (for example from roughly 6 feet to 4 feet), or lowering wall heights that partially block waves. Commission members emphasized the trade-offs: lower walls reduce weight and cost but may let more wave energy overtop and affect F Dock.

Staff said the consultants aim to deliver a preliminary update before the council’s B&O tax vote on Aug. 6 so council members understand repair cost ranges tied to any funding decisions. Commissioners were invited to a scheduled low-tide site visit for city administration, council and staff; staff described those site-visit dates as the week with three consecutive extreme low tides (noted in the meeting as the 24th–26th of the month) and said they would invite commissioners who could attend.

Commissioners asked whether the breakwater is imminently unsafe. Bill said he was “not an engineer” but that, based on recent inspections, he did not expect it to collapse in the next high‑wind event; he recommended proceeding by commissioning the coastal analysis to determine whether repairs, reconfiguration or replacement are appropriate.

Staff and engineers said they will follow up with a cost estimate for the coastal analysis and circulate photos and findings to council and commissioners.