To safely complete the North Fork Nooksack Line Lowering in dry conditions, Barnard implemented a massive dewatering system of 45-ft.-deep wells that pumped 30,000+ gallons per minute.
When the migration of the North Fork Nooksack River in Western Washington put a 30-in.-dia. natural gas pipeline at risk of exposure, Northwest Pipeline, Inc. contracted with Barnard to lower the endangered span. The pipeline crossed the river at a depth of 24 ft. below the ground surface and transitioned to a depth of 4 ft. just 200 ft. from the riverbank. Barnard lowered approximately 1,700 ft. of pipeline to the river crossing elevation and also performed removal, slurry filling, and nitrogen inerting along a previously retired 26.-in.-dia. pipeline. Construction occurred in sensitive riparian habitat that required waterbody and wetland restoration.
Location: Deming, Washington
Owner & Engineer: Northwest Pipeline, Inc.
Contract Type: Fixed Lump Sum (competitive bid) and Fixed Unit Price (competitive bid)
1,700 LF of 30-in.-dia. pipeline lowered
122 dewatering wells
3.5 miles of nitrogen inerting on previously retired pipeline