Pump Station 22 Retrofit & Force Main Replacement Project

Photo of SPU pump station and public shoreline viewing area
SPU pump station and public shoreline viewing area with bench and decorative fencing at the street end of W Cramer St.

Project Description

The Magnolia Basin 60 is a combined sewer basin located south of the Ship Canal and directly to the east of Discovery Park. In this area, stormwater and sewage in the basin is collected and flows to Pump Station 22 located at the street end of W Cramer St. These flows are then pumped through sewer pipes to a regional treatment plant.
 
However, during heavy rain events, high volumes of stormwater could overwhelm the pump station causing a combined sewer overflow (CSO) into Salmon Bay via an underwater outfall pipe. The combined mixture of stormwater and sewage can be harmful to humans, aquatic life, and other wildlife.
 
For the Pump Station 22 Retrofit and Force Main Replacement project, Seattle Public Utilities (SPU) upgraded the pumping capacity of the pump station and the sewer pipeline in the Magnolia neighborhood to reduce the number of overflows in this area and improve water quality offshore. In addition, SPU performed additional upgrades to the pump station as part of the project. This work helps SPU maintain reliable services by reducing the risk of pump station failure, maintaining safe working conditions for SPU crews, and helping SPU comply with safety standards and industry regulations.

Location

Construction occurred along W Cramer St, 40th Ave W, and Commodore Way with most of the work occurring at the street end of W Cramer St.

Project Results

As a part of this project, improvements included:

  1. New pavement and ADA ramps along the alignment of the new force main
  2. Replacement of pump station infrastructure that is near the design life cycle
  3. Better water quality by reducing combined sewer overflows
  4. Improved safety conditions for SPU pump station maintenance crews
  5. The creation of a shoreline viewpoint and public access at the street end of W. Cramer Street in accordance with Seattle Municipal Code 23.60A.578.

Timeline

Construction started in late 2019, and it was completed in late 2020 with final landscaping and construction wrap-up activities occurring through mid-2021.