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Label:
Sewer and stormwater
Label:
Active
Environmental Services is constructing a project to replace a section of large concrete sewer pipe in SW Portland. The Carolina Trunk pipe runs near SW Slavin Road under Interstate 5 to Macadam Ave. It was built almost 90 years ago and needs to be replaced to prevent sewer and stormwater overflows.
Major construction activities began in July 2025. Construction is expected to continue through fall 2028.
The Carolina Trunk is a large sewer pipe - essentially a 3-4 foot wide tunnel deep underground. This pipe is showing signs of deterioration and needs to be replaced. The repairs will maintain sanitary and storm services and help protect public health and the community by preventing sewage releases to buildings and streets.
Project Location
The project area is located in S and SW Slavin Road, between SW Barbur Blvd and S Macadam Ave.
Text description of Carolina Trunk project map
General Schedule
Major construction activities began in July of 2025. Work will be intermittent with phases of inactivity along the project alignment including along Slavin Road, along both sides of I-5, and from SW Corbett Avenue to S Macadam Avenue.
What's Happening Now
Environmental Services crews are working throughout the project area Monday through Friday, 7 a.m. to 6 p.m. Crews may also work on Saturdays between 7 a.m. to 6 p.m. if needed. I-5, Slavin Road, and SW Corbett Avenue will remain open during this work. Expect some delays, and please watch for signs and follow flagger directions to stay safe.
Look-Ahead Schedule
Construction is underway simultaneously in the four work areas. Crews are completing different parts of the underground pipe installation at each location as they work toward connecting the entire pipeline.
The following provides a preview of the work expected in the coming weeks. Work schedules may change in some locations based on securing appropriate permits as well as crew and material availability.
Please note: No work will occur of Friday, July 3rd in observation of the Independance Day Holiday.
Section 1 - SW Slavin Road
Week of June 29 - Week of July 13
- Crews will install a new pipe within the completed underground bore.
The north lane of SW Slavin Road is currently closed through the work zone and will stay closed until approximately fall 2027.
Section 2 – West Side of I-5
Week of June 29 - Week of July 13
- Crews will continue boring underground towards the Corbett Avenue (Section 3) work area.
- Limited night work will occur during the week of June 29 next to Interstate 5 in order to repair a damaged freeway barrier.
Section 3 – SW Corbett Avenue ("Corbett Island")
Week of June 29 - Week of July 13
- Crews will continue excavating and preparing the underground work area to receive the new pipe being installed from the Interstate 5 (Section 2) work area.
Section 4 – S Macadam Ave/S Julia Street
Week of June 29 - Week of July 13
- Crews will continue to fill in the gaps around the new stormwater pipe with grout then begin excavation to prepare for the next phase of underground pipe installation.
Extreme Weather
When high temperatures, extreme heat, near freezing temperatures, or extreme cold are in the weather forecast, crews may adjust schedules to protect workers from the dangers of heat stress and cold stress.
When working in extreme weather environments, all City workers, contractors, and subcontractors must follow Oregon's OSHA (Occupational Safety and Health Administration) mandates and Environmental Services' Heat Illness Safety and Health Plan and its Cold Stress Safety and Health Plan. During extreme weather events, you may see crews taking more frequent water and rest breaks, stopping work at noon, and taking other protective measures.
When the temperature predicted by the National Weather Service are expected to exceed 85 degrees Fahrenheit by 3 p.m. Construction activities may begin at 6 a.m. Monday through Saturday.
With hot weather in the forecast, early work hours will begin Monday, June 22nd. We expect early hours to continue for through the remainder of the summer when hot weather is expected. This is to protect the health and safety of our crews working on this important project. Thank you for your understanding.Pit Excavation Will Generate Noise
Crews are constructing pits throughout the project area. During pit excavation, crews will install steel piles around the perimeter of the pit. Steel plates will be driven into the ground between the piles, and then soil will be excavated out behind the plates. This creates a support structure to hold back the hillside and keep the pit safe for work.
Both of these activities will generate noise and vibration during daytime work hours.
Traffic Enforcement to Increase on Slavin Road
We have recently received reports of drivers not following the traffic control system on SW Slavin Road. The City of Portland will increase traffic enforcement during evening and nighttime hours on SW Slavin Road. The project team will work with PBOT to assess the results of increased traffic enforcement in the coming weeks and may adjust traffic controls and barriers to protect public safety.
Please slow down, and follow all traffic signals, signage and flaggers. Let's do all we can to help keep our neighbors safe during this project.
North Lane of SW Slavin Road Closed Through 2026
Extensive work to excavate and install new sewer and stormwater infrastructure in SW Slavin Road is underway.
To make sure that our crews, residents, and the travelling public stay safe, the north lane of SW Slavin Road has been closed.
Different sections of the north lane of Slavin Road will be closed for approximately 18 months starting in November 2025.
Crews have installed a temporary traffic signal at either end of the work zone that will signal cars through - one direction at a time. Crews will maintain access to properties in the work zone, including driveways and sidewalks. However, there may be some delays.
Please be patient and use caution when using your vehicle in the area. Slow down and obey all signals and signs during this important work.
No Parking on SW 1st near SW Slavin Road
Please do not park on SW 1st Avenue near the intersection with SW Slavin Road. This location is a no-parking zone and needs to remain clear of parked cars to allow traffic to safely access Slavin Road. Crews have installed "No Parking" signs.
If you park in this area, you may be ticketed or towed.
Additional Traffic Impacts
Brief delays along Corbett Avenue and connecting streets will occur during some construction activities. On rare occasions, there may be a need to close the Corbett off ramp. These closures will be limited, and detours will be communicated well in advance.
We do not anticipate traffic impacts on Macadam Avenue, except during a brief period at night near the end of the project.
What to Expect During Construction
Construction creates noise, vibration, and dust and can disrupt normal neighborhood activity. We want you to be safe around the work site. Please keep children, pets, bikes, cars, and trucks away from the tools, machines, supplies, and construction workers. A city inspector will be on-site during work hours and may be able to assist you with construction concerns. Inspectors typically wear a hard hat and safety vest with “City of Portland” on the back.
To learn more about what to expect during construction, please review the brief guide on what community can expect during ongoing projects conducted by Environmental Services.
Impacts to Private Property
Due to limited space in the work zone, it may be necessary for crews to use private property to store materials and equipment, install temporary retaining walls, and conduct construction activities.
City Staff will continue to work with nearby property owners to acquire easements and other permissions for work that may impact some private properties adjacent to Slavin Road. Over the coming months, staff will continue to engage nearby property owners.
Environmental Services staff are working with property owners located within 100 feet of the construction work to videotape structures and install settlement monitoring. Please look for a letter in your mailbox if you live close to the project area.
Noise Impacts
Construction activities generate noise. All work is expected to be at or below City requirements for decibel levels when measured from 50 feet away from the work. Work will include pavement drilling, saw cutting, asphalt grinding, and rock hammering. Crews will be using typical construction equipment, such as trucks, excavators, generators, etc. Some work may occur closer than 50 feet from a residence or structure.
Crews will work to limit noise whenever possible. When appropriate, crews will use sound baffles, white noise backup generators, and other noise reduction measures.
How We Plan to Build the Sewer Trunk
Crews will begin major construction work in July of 2025, by preparing for open cut construction along Slavin Road. At the same time, crews will begin excavating four different pits.
Once the pits are completed, crews will tunnel between each pit and insert new pipes into the tunnels. Finally, crews will connect the new pipes together, restore Slavin Road and fill in the pits, before final clean up and demobilization.
Work will take approximately three years to complete and will occur in phases with periods of inactivity.
Designers have divided the project into four “sections.” Each section has unique characteristics and will require different construction methods. Please see below for a description of the preliminary design for each reach.
Section One: SW Slavin Road
Section One will require substantial work in SW Slavin Road. Crews will build temporary retaining walls at several locations along the north and south sides of Slavin Road to allow for equipment access.
Crews will need to close the north lane of SW Slavin Road and install new sewer and stormwater pipes using the open trench excavation method. All properties will still be accessible during the work.
Once the retaining walls are in place, crews will excavate a pit at the east end of SW Slavin Road. Crews will enter the pit and connect the new pipes in Slavin road to the new pipes coming up the hill from Interstate 5. Once the connections are made and the work is tested and approved, the construction area will be restored.
Section Two: SW Slavin Road to Interstate-5
For Section Two, crews will dig a pit at the bottom of the hill next to Interstate 5 (I-5). Crews will then tunnel underground between the I-5 pit and the Slavin Road pit and install a new pipe. The majority of this work will occur inside an existing City easement.
Section Three: I-5 to S Corbett Avenue
For Section Three, crews will dig a pit inside the traffic island located on Corbett Avenue, between I-5 and the freeway off ramp. Crews will then tunnel underground underneath I-5, between the pit in S Corbett Avenue and the pit on the other side of I-5.
Section Four: S Corbett Avenue to S Macadam Avenue
For Section Four, crews will dig a pit in the Julia Street Right-Of-Way, near S Macadam Avenue. This pit will be located in an existing parking lot that is partially owned by the City of Portland. Crews will then tunnel underground between the Macadam pit and the pit located up the hill next to S Corbett Avenue.
Once all the tunnels are complete and the new pipes are installed, crews will connect the newly constructed system to the existing system underneath S Macadam Avenue.
Project Background
Sewer trunks are an important part of the City’s sanitary sewer system. Smaller neighborhood sewer lines connect to these trunk lines, which then carry flow of sanitary sewage to treatment facilities. The Carolina Trunk travels under I-5, which makes this project a high priority.
This area of Portland presents its own challenges that the project team must consider. Much of the project area is located on old landfill that is covering an old stream bed. The steep terrain in this part of Portland also presents challenges that the engineers must consider when designing the new sewer pipe alignment.
The current trunk line runs underneath private properties, making it nearly impossible to repair without temporarily displacing residents. Given these challenges, the design team has proposed a new alignment (see map above) that accounts for these challenges. This new alignment will move the trunk and other infrastructure under existing right of way and permanent easements and provide access points to make it easier to maintain in the future.
We Want To Hear From You
We would like to hear from you about special events, school activities, and community services in your neighborhood you think may be impacted by this project. Also, we want to know if you have any concerns related to business operations, disability or mobility issues, medical or business deliveries, and proposed night work. Your input will help us minimize the impact to your neighborhood during construction.
Sign Up For Project Updates
Environmental Services will inform residents and businesses about project activities and respond to questions and concerns in a timely manner. The following resources will help you stay informed and report concerns:
- Project Updates: To receive email or text message updates for this project, sign up now at Sign Up for BES Project Updates. Updates provided through our free GovDelivery subscription service are the best way to stay informed about what’s happening and what to expect. You can also sign up for bulletins on other projects and topics
- Questions: Contact Aaron Abrams at Aaron.Abrams@portlandoregon.gov or call 503-823-2827.
- Sewer Emergency: Call 503-823-1700 immediately. The City Maintenance hotline is staffed all hours, all days (24/7).