Thursday - June 18, 2015

Auger cast pile drilling begins for new WTP filters

Preparing the subgrade

New filters – northwest of site

The new filters are being constructed where the sedimentation basins were previously located.

Excavation is compete for the new filters, and this week crews started installing the auger cast piles for the foundation. More than 160 piles will be installed for the filters. This work will continue over the next two weeks.

During this time, the large vibratory compactor will be used intermittently to help backfill and prepare the subgrade for the next stage of pouring concrete slabs. The compactor has been used throughout construction in other areas across the site. Although the compactor will be located low in the excavated hole, neighbors close to the site should expect an increase in vibration during this activity. 

Newly excavated area for the filters in the foreground. Existing administration building in the left background. New ballasted flocculation in the right background. 


New administration building – north of site

Crews are tying rebar, installing beams to intersect with the newly installed auger cast piles and preparing the subgrade (pictured top right). This week, the elevator pit walls were poured. Soon, concrete slabs will be poured for the foundation. Neighbors should expect an increase in truck traffic and noise during this time.

Finished water pump station and electrical buildings – center of site

Structural siding is now complete for the finished water pump station and electrical buildings. Crews are finishing up smaller items for the new structures including installing hand rails and windows for the finished water pump station.

Miscellaneous piping work – east and south of site

This week, crews installed a gas line from the plant property line to the new structures. In July, NW Natural will connect the newly installed line to an existing gas line in the center of Mapleton Drive, near the plant site. This will involve excavating a small trench, making the connection, backfilling and placing a temporary pavement patch. A single lane closure will be in place during this work, which is expected to take a few days.

In late June, crews expect to begin installing a 48-inch overflow line on the east of the site. Crews will excavate, form and pour concrete, place the pipe and backfill. This is expected to take about two weeks to complete. Neighbors close to the site should expect an increase in noise and vibration during this activity.

Neighborhood construction meetings – next meeting July 7 at 7:30 a.m.

The next neighborhood construction meeting will be held at Burgerville on July 7 at 7:30 a.m. Please attend to stay up-to-date on construction progress in West Linn and ask the project team questions.

Meeting schedule:

  • The first Tuesday of the month at 7:30 a.m., at Burgerville, 18350 Willamette Drive, West Linn.
  • The third Tuesday of the month at 6 p.m., at the Robinwood Station, 3706 Cedar Oak Drive, West Linn.

Work hours

Work hours are 7 a.m. to 7 p.m., Monday to Friday, and 9 a.m. to 5 p.m. on Saturdays. No work will occur on July 4.

Site plan and glossary

Please refer to the site plan for locations of each structure or our glossary of terms for construction and operation of the WTP.

For more information, please email, call the hotline at 503-697-6502, attend a neighborhood construction meeting or visit