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Traffic Alert: SW Terwilliger Boulevard closing Dec. 5

October 03, 2016

The City of Portland will begin construction in late November on 7,600 feet of an eight-inch sewer in Terwilliger Boulevard from SW Northgate Avenue to Highway 43. The new Terwilliger 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 the wastewater collection system will help protect water quality, public health, and the environment.

Updated on 11/18/2016:
  • Crews began by paving Glen Road between SW Iron Mountain Road and SW Underhill Road on Friday, November 18.
  • Crews are scheduled to close SW Terwilliger on Monday, December 5 and will begin by mobilizing equipment and machinery into the area.
  • Choose an alternate route if you can. Stick to major arterials and avoid neighborhood streets as much as possible.
  • The first phase of construction will begin on SW Terwilliger west of the Highway 43 intersection. The work taking place on the highway will be scheduled at a later date, likely after the New Year.

The city originally planned to start work on this project in May 2014 but postponed it to avoid conflicts with Multnomah County’s Sellwood Bridge project.

Closure Information

For safety reasons, this project will close SW Terwilliger Boulevard 24 hours a day, seven days a week from the Iron Mountain Trailhead, south of SW Castleridge Lane, to Highway 43 (see attached map).

That section of Terwilliger will be closed for the duration of the project, which is expected to last one year.

The city recommends taking SW Taylors Ferry Road to get to SW Terwilliger from the north.

The Terwilliger Trail will remain open to pedestrians and cyclists during construction (see attached map). There will be advance notification of any closures needed to construct sewer branches to properties along the trail.

Note to Lewis & Clark Community

Due to an expected increase of congestion due to rerouted traffic, please use extreme caution when commuting on Palatine Hill Road and Military Road. 

For More Information

For more information, and to sign up for the email update list for updates during construction, go to

Receive Project Traffic Alerts by Text

You can receive text messages of urgent traffic alerts by simply requesting to be on the text message list. Messages are 1-2 sentences long and convey urgent information such as road closures and openings. Major mobile networks are capable of this, but message and data rates may apply. To receive alerts please sign up on with the City of Portland.

What to Expect During Construction
  • Work hours will typically be 7 a.m. to 7 p.m., Monday through Friday. The contractor may schedule work on Saturdays as well.
  • Construction creates noise, vibration and dust and disrupts normal neighborhood activity.
  • Crews will use open trench to install the new pipe and manholes on the lower portion of SW Terwilliger. A contractor will also use Horizontal Directional Drilling to reduce impact where possible. Visit to learn more about construction methods and to view example pictures.
  • Sewer, water, and other public utilities will remain in service during construction.
  • There will be traffic delays during construction hours.