The Willamette Water Supply System Commission’s goal is to provide a stable and seismically resilient water supply for ratepayers in Washington County. The cities of Hillsboro and Beaverton, along with the Tualatin Valley Water District, have come together to build more than 30 miles of large-diameter pipelines, expand the existing raw water facility, and modify an intake on the Willamette River near Wilsonville, a new raw water filtration facility near Sherwood and water reservoirs on Cooper Mountain.

James W. Fowler Co., serving as the trenchless subcontractor for general contractor Kiewit, is constructing a 270-foot pipe ram of 84-inch-diameter steel pipe underneath Arrowhead Creek, the 55-foot-diameter by 54-foot-deep secant pile launch shaft and 25-foot-diameter by 45-foot-deep secant pile reception shaft, 500 feet of 66-inch welded steel pipe, approximately 1,000 feet of underground utilities, tie-in to the existing pipeline, cleaning and pressure- testing of the pipelines, and other miscellaneous items to complete the pipeline installation. The pipe ram was completed below the water table in cobble- and boulder-laden ground using specialized equipment.

The Raw Water Facilities 1.0 project is an effort on behalf of the City of Wilsonville and the Willamette Water Supply Program to build improvements in and around the Willamette River Treatment Plant in Wilsonville, OR. The goal of the project is to provide an improved pump station, seismically reinforce the Willamette River bank, increase intake capacity, build a new electrical building and standby power along with a new raw water pipeline.

The scope of work included: 270-feet of 84-inch O.D., 1.25-inch thick steel casing pipe ramming, a main utility installation of 270-feet of 66-inch O.D. butt welded pipe, and approximately 50-feet of 66-inch riser pipes and fittings. As noted above, JWF was responsible for managing the secant shaft installation, excavation, and backfill.

The difference in contract amount is due to change orders that included the need to construct a temporary construction equipment and vehicle access to the project’s trenchless crossing receiving shaft and removing boulders larger than 36-inches in the pipe ram cleanout operation. An unidentified 8-inch PVC utility was also discovered in the excavation area for the new sanitary sewer manhole at Brockway Drive. In order to complete the sanitary sewer, the Owner directed JWF to cut and move the line, resulting in another change order.

This project is a small subset of the larger Willamette Water Supply program, a project estimated to cost $1.3 billion. The new water system is engineered to withstand natural disasters, protect public health, and speed recovery in emergency situations. The system will use one of the largest rivers in Oregon as the supply source, the mid-Willamette River. The planned new state-of-the-art water treatment plant will ensure access to top quality drinking water.

While most of JWF’s contributions to the project will be underground and not visible to the public, we are still proud to do our part to help ensure the supply of safe drinking water for current and future generations.

Client

Willamette Water Supply

Region

Oregon

Capabilities

Tunneling, Utilities