Environmental Services has completed design of a project to reconstruct the public sewer system in NW Thurman Street and the Willamette Heights neighborhood. Sewer and stormwater improvements will increase the capacity of the 100-year-old sewer system, relieve basement sewer backups at 31 properties, and reduce street flooding at 16 locations.
The contractor advertise, bid, and selection process will continue through May 2020. Construction is anticipated to begin in June 2020 and will take a year and a half to complete. The project is expected to require two dry-weather seasons to complete construction - June 1 to November 30, 2020, and June 1 to November 30, 2021.
The map below illustrates where this project will construct sewer improvements. The primary construction method for each pipe segment is noted.
The purpose of this project is to relieve basement sewer backup risk at 31 properties in the project area. To that end, this project is looking at upsizing or repairing portions of the 100-year-old public sewer main line to increase its capacity to handle combined sewer and stormwater.
Engineers are also exploring ways to reduce rocky debris in stormwater that drains from Forest Park into the combined sewer in NW Thurman Street. This, too, is to help increase the capacity of sewer pipes and reduce basement sewer backup risk.
Designing this project is complex due to several challenging conditions -- multiple soil types, buried trolley tracks, curvature of the street, nearby landslide recovery efforts, location of other utilities, limited parking supply, traffic controls, and the bridge. These and other factors will make reconstructing the sewer system challenging. The soil sampling and compaction tests that we completed in August 2017 helped engineers better understand some of these conditions.
Coordination with Transportation
The Portland Bureau of Transportation (PBOT) is coordinating landslide recovery work on NW Thurman Street. Although PBOT has not completed their street restoration work, Environmental Services will still proceed with sewer construction. The alignment for the new sewer will be designed and constructed to avoid conflict with the PBOT restoration area. For questions about PBOT's landslide recovery work, please contact Geren Shankar at 503-823-4793.
Sewer construction will also require removing buried trolley track rails and ties to install new sewer pipes. After a construction contractor is selected in the spring of 2020, the contractor will propose the removal methods, a sequencing plan for construction activities, and a general schedule.
As is standard with all sewer projects, Environmental Services will coordinate with PBOT on street permits, street restoration requirements, and safe traffic controls. Any pavement disturbed by this project will be restored per PBOT's guidelines.
Because the neighborhood has been through other major construction projects recently, including a bridge replacement in 2014 and a paving project in 2012, we understand that residents may be growing weary of construction activities and traffic controls. Thank you for your patience and cooperation as Environmental Services works to complete this major capital improvement project to provide another 100 years of public sewer service.
For More Information
If you would like more information about the project or have questions and concerns you’d like to discuss, please call or email:
If you have a question about pipe work near you, please include your name, property address, and project name (NW Thurman) in your voicemail and email so we can provide you more details about what to expect in front of your property. Also, please write "NW Thurman" in the subject line of your email. Click SIGN UP to sign up for periodic email updates.