Hannah Mason Pump Station at Willamette Park


This client needed to replace an aging pump station that was originally built in 1912. Located within a park setting and along a greenway trail, this structure would be highly visible to the public. Therefore, aesthetics was a key consideration for this project, making the structural design of the new pump station critical. The presence of liquefiable soils further complicated the structural foundation design.

PSE was selected to design and construct the new pump station largely due to our deep wastewater expertise. After careful consideration, we proposed a design that would fit seamlessly within the surrounding recreational area and also provide an opportunity for community engagement and education around the high-quality drinking water that it would provide. With the client’s approval, PSE designed and constructed the building to withstand a cascade subduction-zone seismic event and maximum river flow from a 100-year storm. The foundation was built with 350 aggregate piers extending up to 18’ below grade, and the multi-level building incorporated many unique features in close coordination with the project team and a multitude of engineering design disciplines.

Upon its successful completion, the new Hannah Mason Pump Station building in Willamette Park is recognized as a LEED Gold certified facility, which processes upwards of 14 million gallons of water per day. Its design consists of architectural and environmental features such as extensive green roofs, bird-friendly glass in all windows, textured concrete and inlay designs and a storm-water runoff management system. Moreover, the building functions as a multi-use facility housing not only the high efficient pump assembly but also public ADA restrooms and park equipment storage.

The pump station’s design has quickly become a heavily used and beloved community asset which unobtrusively blends into the surrounding environment. Furthermore, this project also received an Engineering Excellence Honor Award from ACEC Oregon.


  • Structural design for multi-use facility

  • Multi-floor building design

  • Green roof loading design

  • Seismic design for cascade subduction-zone

  • Structural design coordination for enhanced architectural features

  • LEED Gold certified

  • Aging infrastructure replacement

  • Award-winning design