City engineers and consultants presented findings July 1 from a year-long Edmonds Marsh Estuary Planning Study, concluding that restoring a tidal connection between the marsh and Puget Sound could expand habitat, support juvenile Chinook usage and provide flood protection for Harbor Square — and that full excavation of the Unical site, while beneficial for habitat, is not necessary to achieve the modeled flood-reduction benefits.

What the study looked at: Blue Coast Engineering constructed a two-dimensional hydraulic model that combined freshwater inflow from Willow and Shalimar creeks with tidal and storm surge conditions in Puget Sound. The model validated existing flooding observations from the December 2022 king-tide/storm event and simulated future scenarios including a 3.2‑foot sea-level rise scenario (a higher-end projection drawn from University of Washington Climate Impacts Group guidance used in regional planning).

Key technical findings: Kathy Keteridge, principal coastal engineer for Blue Coast, reported the model showed reopening an open-channel connection beneath the railroad improves drainage behavior and that simply excavating the Unical parcel to add storage depth does not materially reduce peak flooding once the marsh is tidally reconnected. “What we found is it actually doesn't help flooding, at all to excavate out the Unical site,” Keteridge said, explaining that a restored marsh becomes driven by coastal water levels as well as freshwater inflow, so deeper excavation does not lower tidal elevations.

Ecological and programmatic findings: Presenters said the restoration would double estuarine habitat acreage, improve juvenile Chinook rearing habitat (an important food source for southern resident orcas), and expand habitat for birds and other wildlife. Bill Derry of the Edmonds Marsh Estuary Advocates said the Unical property is the critical parcel to acquire for a full estuary restoration: “First is that we need the Unical property to restore the estuary for the marsh and to expand the marsh,” he told the council.

Contamination and regulatory context: Anchor QEA performed a contamination-impact analysis and reported that most of the Unical site has already been excavated and replaced with clean fill; remaining contamination would not preclude restoration but would affect excavation methods and construction risk management. Consultants described standard mitigation options (caps, liners, controlled excavation methods and construction monitoring) that can avoid mobilizing contaminants during restoration work and said future landowner liability and coordination with Ecology (Model Toxics Control Act processes) are important early steps.

Costs and funding: The completed planning grant (NOAA/National Fish and Wildlife Foundation) totaled about $135,000 with a local match of roughly $91,000 (total $226,000). The team submitted a pre-proposal for follow-on funding to advance pre-design; the next-phase project budget is estimated at about $940,000, with a requested grant portion of about $647,000 and the remainder to be provided by a mix of city staff time, volunteer match and cash/in‑kind contributions. Project proponents said federal, state and private funding sources (including national foundation rounds) are currently available for estuary restoration.

Next steps: The team will submit a full grant application (deadline July 17), and if funded move to a three‑year predesign and 30% preliminary‑design phase to produce a go/no‑go decision for restoration, appraisal and acquisition steps. Consultants emphasized continued coordination with the Tulalip Tribes and other regional partners for fish monitoring and permitting.

Council reaction: Councilmembers thanked volunteers and staff for the technical work and widespread community engagement. Several councilmembers asked that the project continue to pursue tribal partnerships and additional grant funding. Staff said the city will continue to support the effort while consultants pursue the next funding round.