Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Waterfront Lagoon Redevelopment topic
No spam. Unsubscribe anytime.
St. Helens reviews plan to convert waterfront lagoon into confined disposal facility; technical, flood and seismic risks remain
Summary
Consultants told the city council the lagoon at the former veneer and Cascade Tissue sites could be converted into a confined disposal facility to accept dredged sediments (including Portland Harbor material), and that updated geotechnical work, permitting and risk analysis are needed before any construction decision.
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 constraints, permit requirements and design trade-offs that must be resolved first.
Most important findings and constraints
- Bedrock depth and liquefaction risk: The consultants reported highly variable depth to bedrock under the lagoon. In much of the footprint basalt is near the surface, but in a portion (identified in the presentation as "Area C") bedrock plunges as much as 300 feet and is overlain by soft alluvial silt. That silt is prone to liquefaction in seismic events, making Area C "not viable for developing into a landfill," the consultants said.
- Floodplain and liner flotation risk: Portions of the proposed landfill liner could fall below the 100-year flood elevation. Kathy Lombardi said the liner could be "anchored" or the design could raise the facility above flood elevation, but that raising the elevation would reduce capacity and affect financial viability.
- Permits, classification and material acceptance: Consultants said the design would need to meet Oregon DEQ requirements for solid waste facilities; the concept discussed is for a Subtitle D (municipal) confined disposal facility that would not accept hazardous wastes destined for Subtitle C facilities. Material arriving from the harbor would need sampling and characterization; the facility would have checkpoints and the city (or an operator) could decline loads that did not meet permit limits.
- Funding and schedule context: The presentation described prior funding from an EPA grant for the riverfront master plan, a Business Oregon market study in 2016, FEMA funding for further investigations, and state legislative appropriations that fund the current phase of work. Consultants said follow-up Phase 1C geotechnical investigations, updated permitting design and risk assessments are funded and planned, and that construction—if pursued and permitted—would likely align with anticipated dredging timelines around 2030.
- Capacity, revenue and timeline estimates: The earlier 2016 study estimated 2–4 million cubic yards of capacity; consultants said demand projections exceed that. Using a planning assumption of about 200,000 cubic yards of material accepted per year, the consultants estimated roughly 10–15 years to fill a facility of the contemplated size, depending on whether the wastewater plant remains in place or is relocated.
Discussion and unresolved issues
Council members and residents asked about long-term liability, who would operate the facility, monitoring and manifesting of incoming material, shoreline and drinking-water risks, and the fate of contaminants currently in the lagoon. Art Latskovich, a resident, urged more attention to the city's downstream drinking-water intake and shoreline contamination at the barge unloading area.
Consultants repeatedly emphasized that the concept is one option among several and that significant design, permitting and monitoring details remain to be resolved. "We don't think doing nothing is an option," the consultants said, but they also said designs can be adjusted to reduce risk and that DEQ will vet facility design, operation and closure under its solid-waste permitting process.
Next steps and city direction
Consultants said they will proceed with the Phase 1C scope: additional geotechnical borings, stability analysis of the berm, design refinement to a permit-ready level, and air‑quality and risk modeling for different material types. No formal council decision to proceed with construction or to accept dredged material was taken at the March 19 session; the presentation served as an informational update and to surface technical questions the council said it wanted addressed.
The city packet and consultant reports were referenced as available; council members asked staff to ensure the technical reports are provided to the council and made available to the public.
