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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

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SW Terwilliger Blvd Sewer Project Update

SW Terwilliger Boulevard Sewer Project Update: October 18, 2013

Environmental Services is designing a project to construct 6,800-feet of eight-inch gravity sewer in Terwilliger Boulevard from SW Powers Courtto Highway 43. The new sewer will connect to the 30-inch Tryon Interceptor sewer, which carries sewage to the Tryon Creek Wastewater Treatment Plant in Lake Oswego. This improvement to Portland’s wastewater collection system will help protect water quality, public health, and the environment.

Environmental Services staff heard a lot of questions, comments and feedback about the project at a September 19 public meeting. Following the meeting, staff from Environmental Services, the Portland Bureau of Transportation and Multnomah County met with Sellwood Bridge Project contractors to discuss scheduling and traffic impacts. Environmental Services is working with a consultant on more traffic analysis to help determine the scheduling of the SW Terwilliger Boulevard Sewer Project. We are also taking into consideration the impacts to property owners of delaying the project and the potential of the failure of the Powers Court Pump Station. Below are some answers to the comments and questions raised at the September 19 meeting.


Feedback received from residents included the following, which Environmental Services relayed to the traffic consultants doing additional analysis.

  • Greenwood/Breyman at Highway 43 currently has no left turn. Will the left turn-only signal be turned off?
  • Midvale Road, right turn is unsafe. Can there be a permanent right turn here? Turning left onto Midvale from Highway 43 is dangerous.
  • Proposed route instead of Midvale would be Glen Road to SW Iron Mountain Road, to SW Edgecliff toSW Greenwood.Glen Road is in grave disrepair.
  • Palatine Road and Military Road are dangerous.
  • Stampher Road access is difficult already.
  • Requests for temporary stop signs


These questions and concerns came up regarding children and student safety.

  • Environmental Services is meeting with First Student regarding the school bus routes to Riverdale High School and Grade School.
  • Riverdale Grade Schoolis at risk if traffic is rerouted. Military Road is already 45 mph, and there are no sidewalks. Environmental Services will work with the Clackamas County Sheriff to calm traffic near the school if there is a problem.


Environmental Services will communicate regularly with the fire stations and police in the cities of Lake Oswego and Portland, the Clackamas County Sheriff’s Office, American Medical Response and 9-1-1 Dispatch. There will not be a delay in response time to residents in the area. 


Unincorporated Multnomah County: While your property along SW Terwilliger will have access to the future sewer line, you are not required or allowed to connect to it unless you annex into the City ofPortland. According to state law, if your private onsite sanitary sewage disposal system (i.e. septic system) fails, you will be required to connect to the public sewer, thereby annexing into the City ofPortland. As long as your private sewage system is operating in unincorporatedMultnomahCounty, you are not required to hook up or annex into the City of Portland unless you choose to.

  • Contact Ken Martin at 503-222-0955 or to ask questions about annexation or to start this process.
  • Contact Chris Collett at 503-823-4108 or to answer questions about city fees involved to connect to the City of Portland public sewer. This would include sewer line, lateral branch and system development charges, costs associated with annexation, as well as private plumbing costs.

Clackamas County/Birdshill neighborhood: Environmental Services is extending sewer lines and manholes into Underhill Road and Midvale Road in anticipation of future connection for the City ofLake Oswego, should the city choose to connect to the City ofPortland public sewer.

Tryon Creek Wastewater Treatment Plant (TCWTP): The new sewer will connect to the 30-inch Tryon Interceptor sewer, which carries sewage to the TCWTP in Lake Oswego. There was a neighbor that was concerned that the TCWTP didn’t have the capacity for this new sewer. There is sufficient capacity at the TCWTP. There is a group working on a facilities plan update, which is standard practice every 10-15 years for Environmental Services.

For More Information

Go to To receive email updates for this project, send an email to Ashley Tjaden at with “Terwilliger” in the subject line.

Thank you for your cooperation during this project. Please let us know if you have concerns such as business operations, disability issues or medical or business deliveries. As always, we strive to provide a quick response to your concerns, minimal disruption of your residence or business, and open and honest communication with you throughout the project.