WWU students present findings, recommendation on Edmonds Marsh

More than 50 citizens took time out from their Friday afternoons to attend a presentation by Western Washington University students and professors on proposals they developed as a result of a year-long intensive study of the Edmonds Marsh.

“This is all part of the Sustainable Cities Partnership between the City of Edmonds and WWU,” explained consultant Keeley O’Connell, who is overseeing the project for the city. “The agreement provides for students and professors to partner with the city to identify and work on an array of sustainability projects.  It’s a great opportunity for both parties. The students get hands-on experience with real issues, and the city gets the benefits of enhanced sustainability.”

The entire project comprises approximately 11 student groups working on various sustainability-enhancing initiatives. While several target the Marsh, others include GIS mapping of the Edmonds Memorial Cemetery, advancing the Fourth Avenue Arts Corridor and developing a downtown walking tour smart phone app. The Marsh-related projects are completed by students under the direction of WWU Professors Dr. John Huxill and Dr. Jim Helfield. (See earlier My Edmonds News article here.)

While some studies are still in progress and final reports have yet to be completed, three of the groups working on marsh-related projects presented their results to the public at Friday’s meeting. The reports covered Harbor Square stormwater management, vegetation in the marsh, and alternatives for expanding and enhancing the boardwalk.

The stormwater management proposals were aimed at mitigating runoff from the built environment of Harbor Square into the Marsh. Recommended measures included replacing the current impervious parking and walkway surfaces with permeable materials that allow water to seep through to the substrate rather than flow unimpeded into the Marsh, replanting existing landscape islands in the parking areas as rain gardens, and utilizing innovative portable rain gardens called “splash boxes” to slow and filter runoff from roofs.

The marsh vegetation proposals focused largely on controlling the spread of non-native invasive species such as Japanese Knotweed and Purple Loosestrife that have already taken over several sections of the marsh and threaten to push out native species. By depleting the marsh’s biodiversity, these plants destabilize the ecological balance necessary for a sustainable, healthy marsh, thereby decreasing its ability to withstand ecological stress from rising sea levels, climatic aberrations and other factors. Because the various invasive species have different characteristics, control methods need to be tailored to the targeted species in order to be most effective, and include such things as manual control (pulling them out), targeted herbicides, and bio control (e.g., with an insect predator that specializes in the targeted plant only).

Enhancing usability by expanding the current boardwalk would further open the marsh to birders and wildlife enthusiasts, and serve to connect City Park, the Willow Creek Fish Hatchery, and the existing boardwalk with an elevated ADA accessible walkway. Three proposals were developed and vetted with various stakeholder groups to assess the preferences of potential users. Of paramount concern was the possible impact of an expanded boardwalk on the Marsh and the various species of flora and fauna that it supports. The final recommendation draws elements from all three initial proposals, and calls for increasing community health, mitigating the boardwalk’s environmental impact, matching the project with the community’s needs, enhancing educational opportunities, and minimizing adverse human-caused impacts (for example, vandalism).

The full report on the studies presented Friday is available on the City of Edmonds website here.

More information on the WWU/Edmonds Sustainable Cities partnership, including reports from the non-Marsh studies (some of which will be posted as the projects complete) is available here.

— Story and photos by Larry Vogel


  1. The categories of marsh boardwalk uses seem unnecessarily confusing. The only purpose should be for observation. Observation may include photography or learning or exercise, but it’s still observation. It seems to me the issues come down to observation vs. disturbance. How can observation be improved without disturbing the wildlife? Perhaps the observation features (walks and platforms) should be hidden from the birds. Why would we want to expand the access for folks to exercise if they’re not interested in observing the marsh and/or its wildlife?

  2. Great presentations and there will be two more reports relative to the Marsh and Sea Level rise which will be on the website. The work that the students did was excellent and provided various ideas and methods to mitigate current storm water issues without redevelopment. I was also impressed with the invasive species which as a City Council, we should probably start looking at methods to measure and monitor and hopeful eradicate. I realize that once salt water flows freely into the Marsh that some of the invasive will naturally be killed off, but better to start now rather than wait since the students provided us with some very good data.

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