Process as theater
The Georgetown Wet Weather Treatment Station (GWWTS) is the first in a series of King County combined sewer overflow projects aimed at restoring the ecological health of Seattle’s waterways. Completed in 2022, the GWWTS will annually treat 70 million gallons of stormwater and wastewater that would otherwise be discharged untreated into the Duwamish River. In addition to its primary infrastructural function, the project incorporates design considerations prioritizing local community input such as thoughtfully siting the treatment station into Georgetown’s dense urban context while integrating community, cultural, environmental, and interpretive elements.
The Design
Located at a prominent intersection in the community, the project acts as a gateway at Georgetown’s western edge. Siting the essential facility in the densely packed industrial and neighborhood context focused on creating a boundary condition that was both secure and also respectful to the surrounding neighborhood. Cohesive building massing and clustering, secure yet visible permeable perimeters, and expressing material datums across the campus of buildings were design strategies used to relate the industrial scale to the human scale.
The project’s Operations and Maintenance Building anchors itself at the most visible corner of the site to act as the strong and welcoming public identity for the facility. Larger structures housing heavy infrastructural components, are located further away from the public edge. Native plantings and bioretention gardens are integrated inside and outside of the secure perimeter, helping the connect the inside of the facility to the community beyond the fence.
Sustainability
In 2018, the project was awarded Envision Platinum certification, the first in Washington State. Sustainable practices built into the design and construction plans included demolition waste diversion plans, sustainable material selection, sourcing, construction practices, resiliency and on-site stormwater management.
During design, the multidisciplinary design team worked diligently to reduce project waste by 85% through reuse and recycling. An existing warehouse building on the site was demolished prior to construction. Through early planning, the design team was able to recycle 100% of the existing concrete for non-project-related purpose, and re-use old growth timber beams from the warehouse in the interior of the Operations and Maintenance Building’s training room.
Green water infrastructure strategies included permeable pavements, bioretention planters, bioswales, vegetated roofs, and rainwater reuse. Cisterns, visible to passerbys at the south edge of the site, collect up to 50,000 gallons of rainwater and offset 50% of the site’s irrigation.
A 2.3kW PV system on the operations building allows the building to generate solar energy for the site with the capacity to support a 100kW system. Additional solar ready zones have been built into the project to support the capability to expand PV system in the future.
Design Collaborator & Architect of Record: The Miller Hull Partnership, LLP
Design Collaborator: Signal Architecture + Research
Engineer: Jacobs Engineering Group
Contractor: Flatiron Construction
Landscape: Berger Partnership
MEP Engineering & Structural: HDR
Lighting: Blanca Lighting Design
In 2021, Miller Hull launched the EMission Zero initiative — a program targeting the elimination of greenhouse gas emissions in the built environment. A major component of EMission Zero is Miller Hull’s commitment to voluntarily purchase Green-E certified carbon offsets to cover the embodied emissions of each built project upon completion.
Click here to see the EMission Zero information for this project.