Skagit River Raw Water

Project Summary

On the Skagit River Raw Water Pipeline and Clearwell project, IMCO constructed a new raw water pipeline and water storage tank, also known as a clearwell. IMCO crews installed a 42-inch diameter pipeline up to 50-feet below the riverbed of the Skagit River using horizontal directional drilling. Construction of pipe segments and tie-ins were installed to the existing raw water pipeline and associated valves and appurtenances.

The project included construction of a new 2.1-million-gallon welded steel water storage tank, yard piping, valves, instruments, appurtenances, and a concrete vault associated with the new clearwell. IMCO coordinated the integration of instrumentation and controls, and SCADA programming and testing, and provided assistance during commissioning of the new facilities.

The city of Anacortes is a major provider of water in the region supplying water to 60,000 people, including those in Anacortes, the town of La Conner, two refineries in Skagit County, the Swinomish Indian Tribal Community, the city of Oak Harbor, and the Naval Air Station on Whidbey Island. The new pipeline will serve as a backup in case the city’s old raw water line — which was built in 1970 — breaks or needs maintenance and the new clearwell provides additional storage capacity. The project also benefits the Skagit PUD, which receives water from Anacortes through intertie connections to supplement its water system during drought conditions.



Anacortes, WA


City of Anacortes

Contract Amount

$10.6 million


June 2020 - July 2021

Project Highlights

IMCO crews pulled just under 2,000 lineal feet of 42-inch welded steel pipeline under the Skagit River from the treatment plant to the intake. Utilizing three cranes, the pipeline was lifted into the air and a subcontractor used a drill rig to pull the pipeline through the tunnel previously drilled to house the new raw water pipeline. At its deepest, the pipe was 50-feet below the riverbed.