The Edmonds Marsh is a saltwater estuary formed where Shellabarger Creek and Willow Creek flow into Puget Sound. On the oldest street map of Edmonds I found, from 1900 or so, it is labeled simply “marsh.” It extends south from Dayton Street to the bluff where the Point Edwards Condominiums now stand, and east to just beyond what is now Edmonds Way. Even on that map, though, a dike carrying the Great Northern Railroad (now BNSF) tracks separates the Marsh from the Sound. Land use maps dating to 1897 show heavy logging near the immediate shoreline.⁠

Covering almost 100 acres on those old maps, the Marsh is now only 22 acres, but it still plays an important role in the ecology of the Edmonds shoreline.

Estuaries represent transitions, from freshwater streams to the saline ocean. They are among the most diverse ecosystems in the world, with species evolved to not just survive, but thrive in the changing conditions. Temperate estuaries are less thoroughly studied than those in the tropics, but researchers at the University of Victoria found that the Cowichan Estuary on Vancouver Island captured twice as much carbon as an equivalent acreage of 20-year-old forest.⁠

Temperate estuaries contain at least four different habitats. The wettest and most saline, the oyster beds, lie at the edge of open water and are submerged most of the time. A little closer to shore, mudflats are typically exposed at low tide. They lack visible vegetation, but host algae, photosynthetic microbes, and invertebrates that feed on them. Still closer to shore, eelgrass meadows provide food and shelter for young salmon and forage fish. The water here is still salty, but not as deep, allowing correspondingly more light for photosynthesis.

salty transition

Still further inland, the marsh habitat varies in salinity with the tides and the time of year; the boundary between “saltwater” and “freshwater” marsh species is not clearly defined. The wet winters of the Salish Sea bring abundant flows of freshwater and the sediment it carries. In our drier summers, freshwater flow diminishes and saltwater moves further inland. However defined, estuary marshes are critical habitat for salmon during smoltification, the transition from freshwater to saltwater metabolism. In these relatively safe waters, young salmon can feed and grow for up to a year, depending on the species. Young salmon from throughout Puget Sound use stream estuaries and coastal embayments as important way stations en route to the ocean. Besides salmon, mussels and forage fish linger among salt-tolerant reeds. Both resident and migrating birds use marshes to rest, feed, and breed. More than 190 species of birds have been observed in the Edmonds Marsh, for example.

As the water becomes less saline, freshwater species like cattails replace salt-tolerant reeds. Frogs, turtles, and other species that require ready access to land become more prevalent. Eagles, herons, and song birds nest in surrounding trees.

The Encyclopedia of Puget Sound defines all of Puget Sound as an estuarine system.⁠ Its depth and the tidal flow through the Straits of Georgia and Juan de Fuca drive the exchange of water between the Sound and the open ocean.

Map courtesy of National Oceanic and Atmospheric Administration (NOAA)

This giant cedar stump near the Willow Creek fish hatchery still shows where early loggers cut notches into the wood so they could insert springboards. The springboards provided platforms where loggers could stand as they cut the tree down. photo by Sara Noland

Still, Ferguson explained, there is a lot of work to be done. Though saltwater flows into the Marsh again, it does so through a 1600-foot pipe extending deep into Puget Sound. Salmon from the Willow Creek micro-hatchery in the southern corner of the Marsh property can reach the Sound, but none can return. Upstream, much of the water that once flowed into Willow Creek now passes over roads and parking lots before making its way to a system of stormwater drainage pipes. This water — full of petrochemicals and other compounds, many of them highly toxic to fish — currently flows untreated into the Sound.

In the Marsh itself, parts of the former Unocal tank farm remain highly contaminated. Fully reincorporating it into the Marsh ecosystem would involve removing and replacing large amounts of contaminated soil. The project is made more complicated by the positioning of a stormwater pipe directly under the former Unocal property.

While details like these add complexity, the City of Edmonds is continuing restorative work. The next step considers alternative ways to daylight Willow Creek. Freed from its current drainage pipe, the Creek could facilitate access to the Marsh for young and returning salmon.

Improving tidal flows along the Willow Creek channel would improve water quality. Improved riparian habitat along the Creek would support a more complete ecosystem. Creek restoration alone is not enough, though. Contaminated sediments and stormwater contamination still need to be addressed as well.

Elsewhere in Puget Sound, a few restored estuaries have recovered to something approaching their pre-settlement conditions. The success of potential restoration projects depends on the amount of ecosystem degradation, with heavily industrialized sites like tank farms posing many more challenges than former agricultural sites like the Nisqually NWR. Upstream water sources vary in quality as well. The sources of the Nisqually and, on the Olympic Peninsula, the Elwha lie in protected National Parks. Rivers like the Duwamish and the Shellabarger and Willow Creeks in Edmonds drain more industrial surroundings and bring significant toxins to their estuaries. These differences, in turn, affect the cost of restoration projects and the political will to complete them. Successes like the Nisqually NWR show what is possible, but the future of the Edmonds Marsh has yet to be written.

salt marshes and rising seas

Over all of this hangs the looming threat of sea level rise. While humans tend to think in years or decades, the cedars that once overlooked the Marsh can live for centuries. In the short term, estuaries help protect shorelines, providing a buffer between coastal development and pounding waves. In the long term, though, the outlook is grim. By the end of this century, the parking lot near Marina Beach Park where Ferguson and I talked could be under nearly five feet of water at high tide. A spruce or cedar planted on the edge of the Marsh today could drown in saltwater before reaching maturity. Cities and volunteer organizations alike face hard choices as they invest their limited resources. Is the best strategy to plant based on a best guess, or to plant a wide variety of species and allow nature to pick the winners? What happens to contaminated soils and our efforts to clean them up as sea levels rise?

The future of Edmonds Marsh poses hard questions with no obvious answers. In the present, though, ducks paddle in the brackish water. Seagulls wheel, silhouetted against the setting sun. The Marsh is alive.

Similar ecosystems, large and small, can be found throughout Puget Sound. The largest and healthiest is probably the Billy Frank Jr. Nisqually National Wildlife Refuge in Olympia, Washington.

The Meadowdale Beach Park and Estuary Restoration Project, completed in 2023, faced challenges similar to the Edmonds Marsh restoration. Lund’s Gulch Creek was similarly isolated from the sound by BNSF tracks. The Meadowdale project’s success helps demonstrate what stakeholders can achieve when they work together.

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