St. Helens reviews plan to convert waterfront lagoon into confined disposal facility; technical, flood and seismic risks remain

At a March 19 special session, St. Helens city officials heard consultants from Moll Foster and MFA present updated technical, financial and permitting analysis for the Central Waterfront lagoon and a concept to convert portions of the lagoon into a confined disposal facility to receive dredged sediments, including material from the Portland Harbor Superfund.

The proposal drew on prior planning and multiple grants. "Our intent is to give you some baseline information and then hear what questions you have," said Seth Otto, principal planner with Moll Foster, introducing the presentation. Kathy Lombardi, principal engineer with MFA, summarized findings from updated market and geotechnical studies and said the updated financial analysis shows scenarios that "are in fact revenue positive" for the city.

Why it matters: the lagoon sits next to planned redevelopment parcels and an aging wastewater treatment plant. Converting portions of the lagoon to a confined disposal facility could remove contaminants now in the lagoon, create upland storage for dredged sediments, reduce truck traffic by using barges, and generate tipping-fee revenue the city could use for waterfront improvements and wastewater upgrades. But the consultants stressed substantial technical…