Street Trees Protect Watershed Health in Granite Falls
Our resource planners and project managers provided personalized technical assistance to 220 farmers, residents, and local jurisdictions. An example of this is our work with the City of Granite Falls in the Pilchuck Watershed.
The Pilchuck Watershed is a stunning landscape encompassing parts of Granite Falls, Lake Stevens, and Snohomish. It also includes the Pilchuck River, which joins with the Snohomish River before draining into Possession Sound. This watershed’s beauty draws more visitors and residents each year, increasing development and, in turn, impervious surfaces, stormwater runoff, and water pollution loads. In recent years, water quality testing along the Pilchuck River has revealed high temperature and bacteria levels and low dissolved oxygen levels. This does not bode well for salmon and other native aquatic species that call this watershed home.
In an effort to improve the health of the Pilchuck Watershed, Snohomish Conservation District’s Community Conservation team utilized Department of Ecology funds to complete a spatial analysis of the area. Haly Rylko, SCD Community Conservation Project Manager, worked with Andrew Phay from Whatcom Conservation District to create and analyze a series of maps containing data about existing canopy cover, slope, soil infiltration rates, and additional nearby sites.
This information allowed the Community Conservation team to identify and rank locations well-suited for green stormwater infrastructure (GSI) projects—nature-based solutions that collect, slow, and filter stormwater. At each of these sites, they evaluated the suitability of different practices, including planting street trees, installing rain gardens, depaving (replacing pavement with pervious surfaces), and constructing bioswales.
“It was nice to use the prioritization model to analyze such a wide geographic area and to be able to quickly hone in on impactful potential project sites to bring to our partners,” said Haly.
The Community Conservation team shared their findings with staff at the Cities of Granite Falls, Snohomish, and Lake Stevens and discussed which GSI practices would be most impactful. Snohomish and Lake Stevens were given the tools for later decision making, and staff at the City of Granite Falls decided to move forward with implementing a street tree planting project.
The new red maple trees at Jim Holms Park, along with an educational sign explaining their environmental impact.
The District and Granite Falls worked together to locate two ideal planting sites due to their proximity to high-priority areas: Jim Holms Park and East Union Street. Haly collaborated with the City to select a tree species and chose ‘brandywine’ (Acer rubrum), a red maple tree known for its striking fall colors and ability to tolerate a variety of conditions, including urban environments. The Community Conservation field crew then planted six of these trees along the impervious sidewalk adjacent to the basketball courts at Jim Holms Park. An additional five trees were planted along East Union Street.
In order to help educate the public about the benefits of street trees and encourage residents to plant trees of their own, the District’s Lead Designer, Emma Kilgore, designed informational signs that were installed at one of the planting sites. These signs illustrate how trees benefit our air, water, and soil, and explain how the trees planted as part of this project benefit the Pilchuck River and surrounding watershed.
“It was great to work with Granite Falls on this. They gave invaluable feedback on the model and worked with us to turn one of those potential projects into a reality,” said Haly. “I hope this model and report can continue to evolve and serve as a tool to help implement more of these projects in the Pilchuck Watershed and beyond.”
We look forward to watching these Granite Fall street trees mature and joining residents in enjoying the many benefits they bring to the watershed.
This project was funded in part by the Washington State Department of Ecology.