The content for this article was originally featured in the Daily Journal of Commerce on August 31, 2023.
A CLT bridge traverses the bioswale.
Phase three of the Aurora Bridge Swales project is now completed. Aurora Bridge Swales is an award-winning green stormwater infrastructure project designed to clean toxic stormwater runoff from the Aurora Bridge before it reaches Lake Union.
This extensive multi-year and multi-phase effort comprises three distinct phases of landscaping. Phases one and two are located across from one another at the intersection of Troll Avenue North and North 34th Street in Fremont. The third phase is located about a block away, at the end of North 34th Street on private land at the Fremont Lake Union Center, adjacent to the Burke-Gilman Trail.
At each phase, bioswales full of natural plantings capture, retain and naturally scrub runoff pollutants from the bridge before the water is diverted back into Lake Union. Together, the three bioswales are expected to clean nearly 2 million gallons of toxic runoff annually. The project also beautifies previously dark and dingy sidewalks under the shadow of the highway bridge.
The phase-three bioswale is expected to clean around 1.2 million gallons of stormwater each year.
Phase three is the largest bioswale and is expected to clean around 1.2 million gallons of stormwater each year. An attractive cross-laminated timber bridge crosses the phase-three bioswale and connects North 34th Street to the Burke-Gilman Trail. Construction began on the third phase in 2018 and wrapped up this year. The swale was completed in 2020 but the bridge wasn’t installed until this summer.
The CLT for the bridge was donated by mass-timber manufacturer Kalesnikoff and is sourced directly from the nearby mass-timber lab/office project Northlake Commons.
The under-construction Northlake Commons was designed by Weber Thompson, also the architect for the entire Aurora Bridge Swales project. Turner Construction was the general contractor for all three swale portion phases. Metis Construction installed the bridge.
Aurora Bridge Swales is a collaborative endeavor between COU LLC, a Seattle-based commercial office development entity, Weber Thompson’s landscape architecture studio, Turner Construction, Salmon-Safe, The Nature Conservancy and Clean Lake Union, a nonprofit established to improve regional water quality issues.
Phases one and two are located adjacent to two COU-developed office buildings, DATA 1 and Watershed, and were funded by the private developer (Weber Thompson was the architect for both offices).
Phase three was the vision of Clean Lake Union, which raised the funds for this phase. Additional funding and advocacy came from private companies in Fremont, The Nature Conservancy, Boeing and grants from the state.
Phase one was completed in 2017, phase two was finished in 2020.
A fourth phase of the project is currently under construction as part of the Northlake Commons development. This phase comprises stormwater measures that build on the first three bioswales phases. Phase four taps into a below-grade storm pipe that collects roadway runoff from neighboring streets and cleans it on-site. Weber Thompson estimates that 2.3 million gallons of polluted runoff will be cleaned by this phase annually before entering Lake Union.
Clean Lake Union and the team behind the first four phases are also exploring the possibility of more stormwater infrastructure projects that would clean runoff from five more bridges that cross Lake Union, as well as the south span of the Aurora Bridge, Weber Thompson says. This effort is called the Six Bridges Project and seeks to mitigate over 117 million gallons of polluted runoff from entering the lake.
The Aurora Bridge Swales project and team have been honored with several prestigious awards including a 2023 Urban Land Institute Americas Award of Excellence and a 2022 Honor Award from the Washington Chapter of the American Society of Landscape Architects.