Harbor board hears technical briefing on heavy-lift marine terminal; concrete vs. steel foundations left to environmental review

Engineers and consultants on Thursday briefed the Humboldt Bay Harbor District on how the proposed heavy-lift marine terminal for offshore wind would be used to assemble and launch very large floating foundations—and why whether those foundations are made of steel or concrete matters for local operations and environmental review.

"What we're looking to do in Humboldt is get an offshore-wind port facility that'll service the industry," said Josh Singer, lead technical adviser for Moffatt & Nichol, during a presentation that laid out foundation types, material choices and port equipment needs. Singer described floating foundation types (semi-submersible, tension-leg and spar) and said weights can range from roughly 3,500 to 25,000 tons depending on material and configuration.

The differences matter for logistics and local impacts. Singer said steel foundations are typically fabricated from prepainted components that arrive by vessels equipped with cranes and are bolted together at the port; concrete foundations are produced on site with mobile batch plants and require deliveries of aggregate, cement and reinforcement. "If we do concrete, the vessel delivery profile changes—those steel delivery vessels go away and are replaced by barges carrying materials," Singer said.

Why it matters: commissioners and members of the aquaculture community said the district must evaluate whether concrete production and any increased truck activity, paint touchups, antifouling agents or lubricant handling could affect local air or water quality and shellfish operations. "I would just like to see a lot of transparency as you discover these things rather than have all the studies and evaluations and then we learn about them as we go along," said Robin Grace Stewart, marine chair for the local Sierra Club, asking that early findings be shared with advisory committees and the public.

Singer and others repeatedly emphasized that the environmental and operational tradeoffs will be addressed in the SQA (environmental review) and that developers—not the district—typically choose foundation types. "Concrete definitely needs to be evaluated for environmental effects," Singer said. "I don't think we're there yet to be able to say exactly what those impacts are. That will be part of the project investigation."

Board members pressed specifics on paint and lubricants for preassembled components and on the feasibility of using barge versus truck deliveries. Singer said major paint work is usually done at the manufacturer before arrival, with only touchups occurring on site and that antifouling coatings would be required regardless of material.

The district also reiterated a schedule note: the project has been reactivated after several months of low activity and a public meeting is tentatively scheduled for June 25, hosted by the community advisory committee. Staff acknowledged earlier frustrations from "impacted parties and affected communities" about timeliness and participation and pledged better opportunities for committee members to speak during staff reports and technical briefings.

What happens next: the SQA/environmental review will examine air and water impacts, material-delivery scenarios and other operational details. District staff and consultants said early technical studies and the sediment characterization program will inform permit assumptions; the first toxicity and chemistry results from recent sediment cores were expected in the weeks after the meeting.

The board did not take a formal policy vote on the terminal at the meeting. The public comment period and advisory committee process will continue ahead of any final board actions.