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The City of Portland, Oregon

Environmental Services

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Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

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NW Thurman Sewer Reconstruction


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The City of Portland’s Bureau of Environmental Services is continuing our work to repair and replace critical sewer and stormwater infrastructure. Environmental Services will continue to provide information and updates on construction schedules and activities during the COVID-19 emergency. 

Updated July 8, 2020

Environmental Services will soon begin construction of a project to reconstruct the public sewer system in NW Thurman Street and the Willamette Heights neighborhood. Sewer and stormwater improvements will increase capacity of the 100-year-old sewer, relieve sewer backups, and reduce street flooding.


The contractor, Moore Excavation Inc., plans to mobilize crews in late August 2020 and take a year and a half to complete.


The map below illustrates where this project will construct sewer improvements. The primary construction method for each pipe segment is noted.

Project Map

Pre-Construction Activities

Before construction begins, crews will be in the neighborhood to prepare for trolley track removal and sewer construction. Activities will include inspecting pipes and manholes, locating and marking underground utilities, removing four trees as required, trimming trees and installing tree protective fencing, setting up traffic controls, installing settlement monitoring equipment, setting up erosion controls, staging equipment and materials, and other activities as needed. These activities typically occur over time, rather than all at once. Learn more at

Construction Methods

The contractor will use open trench excavation, cured-in-place-pipe lining (CIPP), and horizontal directional drilling to construct sewer and stormwater improvements. See the map above for the construction method at each location. Most of the mainline public sewer pipes will be replaced with the open trench excavation method. Details and photos of construction methods are available at

This project will also include the following construction elements:

  • Abandon sewer pipes and manholes under the Balch Gulch Bridge and divert sewer and stormwater flows away from the bridge to the existing system at the intersection with NW 30th Avenue. The project will upsize the sewer line north on NW 31st Avenue and east on NW Vaughn Street to NW 30th to accommodate the flows from this diversion. This improvement will avoid compromising the integrity of retaining walls, a water line, the bridge abutment, and bridge pier supports, and improve future access to the system for maintenance.
  • Remove buried trolley track rails and ties to install new sewer pipes. After the construction contract is finalized, the contractor will propose the removal methods, a sequencing plan for construction activities, and a general schedule.
  • Extend the public sewer in NW Aspen Avenue just north of NW Savier Street to resolve nonconforming sewer connections and provide properties an independent connection to the public sewer.
  • A second sewer extension in NW Aspen Avenue just south of NW Belgrave Avenue is still being designed. Whether it will be constructed as part of this NW Thurman project is still uncertain. Environmental Services is working with individual property owners to obtain necessary easements and approvals. 
  • A third, more urgent, sewer extension in NW Aspen Avenue at two properties north of NW Franklin Court completed construction in June 2020 separately from the NW Thurman and NW Aspen projects. 

What to Expect During Construction

The contractor will develop detailed traffic control plans and a general schedule before construction begins. You can expect the following activities and impacts:

  • Noise, Vibration, and Dust: Construction creates noise, vibration, and dust and disrupts normal neighborhood activity.
  • Equipment Storage: Equipment and materials may be stored on streets overnight.
  • No Parking: Little or no on‐street parking will be allowed in and near work zones, especially during work hours.
  • Traffic Delays: Expect traffic delays in and near the work area.
  • Lane Restrictions: At least one lane with two-way traffic on NW Thurman west of 31st will be maintained, with flaggers during work hours to assist traffic and pedestrians.
  • Street Closure: The work at NW Thurman and 31st may require a temporary street closure of NW Thurman. If so, a signed detour will be in place and work hours will be restricted.
  • Cross-Street Closures: Work at intersections on NW Thurman may require temporary cross-street closures, with local access the next block up from the closure on that cross street.
  • Pedestrian Access: If temporary crosswalk and sidewalk closures are necessary, signage will indicate the alternate way for pedestrians to proceed.
  • Services Maintained: Sewer, water, and other utilities are expected to remain in service during construction.
  • Garbage Pickup: Access to garbage and recycling bins for haulers will always be maintained.

Project Background

The purpose of this project is to relieve basement sewer backup risk and reduce street flooding in the project area. To that end, this project will upsize or repair portions of the 100-year-old public sewer main line to increase its capacity to handle combined sewer and stormwater. Engineers have also designed ways to reduce rocky debris in stormwater that drains from Forest Park into the combined sewer in NW Thurman Street. This, too, will help increase the capacity of sewer pipes and reduce basement sewer backup risk.

By the Numbers

The NW Thurman Sewer Reconstruction Project is designed to accomplish the following sewer and stormwater improvements:

  • Relieve basement sewer backups at 31 properties;
  • Reduce the risk of street flooding at 16 locations based on the 25-year Design Storm;
  • Replace or repair 4,800 feet of public sewer mainline pipe, ranging in size from 8 inches to 14 inches in diameter;
  • Construct or replace 95 sewer service laterals that connect private sewer lines to the public sewer in the street; this will involve 1,500 feet of lateral sewer pipe;
  • Construct or replace 32 manholes, of which 1 (one) is a sedimentation manhole;
  • Replace 14 storm drain inlets and construct 280 feet of inlet lead pipe.


Designing and constructing 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, narrow public right-of-way, 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 the project 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.

As is standard with all sewer projects, Environmental Services will coordinate with PBOT on street use permits, street restoration requirements, and safe traffic controls. Any pavement disturbed by this project will be restored per PBOT's guidelines.

Report Basement Backups

If your basement sewer backs up or your property or street floods, please report it immediately to the City's 24/7 Maintenance Operations hotline at 503-823-1700. They will log the issue in a tracking database, visit the location to investigate the issue, make emergency repairs where necessary, and use this information to help plan future improvements to the system. This information will also be used to improve the local surface drainage conditions where possible. Please report an issue as it is happening so responding crews can observe it. We also encourage you to call the hotline to report locations where there is a history of local surface drainage issues.

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:

Cheryl Kuck
Community Outreach
Phone: 503-823-7898

If you have a concern or question about a pipe repair near you, please be sure to 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.