North Dakota Water Project Makes Progress with Multi-Product Solution by Northwest Pipe
NWP-Manufactured Permalok® Microtunneling Pipe, Engineered Steel Pressure Pipe Support the Red River Valley Water Supply Project’s Intake Tunnel and 72-inch Water Transmission Line
The Red River Valley Water Supply Project is a groundbreaking drought mitigation program designed to supply emergency and supplemental water from the Missouri River through a 167-mile pipeline to communities in central and eastern North Dakota. Northwest Pipe Company is supporting this project as the single source of fabricated fittings and trenchless Permalok® pipe for the intake structure, plus an additional 1.2-mile stretch of engineered steel pressure pipe for the water transmission pipeline in the initial phase of construction. Our multi-product solutions package streamlines planning and design logistics, adding value and ease for the project stakeholders.
Located approximately 20 feet off the bank of the Missouri River near the town of Washburn, North Dakota, the intake structure is comprised of a single 72-inch diameter steel pipe segment assembled on-site utilizing multiple custom fittings with a Permalok® T-7 end connection. These fittings include a riser, elbow, and wye, four flanged pipe spools, and two blind flanges. The intake structure is tied to a 1,567 LF drive of 72-inch AWWA C200 trenchless steel pipe with Permalok® T-7 joints. All fittings and trenchless pipe include polyurethane coating and lining applied to AWWA C222 standards. Pipe cylinders and end connections were manufactured at our Permalok® plant in St. Louis, Missouri. Secondary manufacturing processes including hydrostatic testing, the application of coatings and linings, and fabrication of the structures and custom fittings were completed at our engineered steel facility in Parkersburg, West Virginia.
Project contractor Michels selected microtunneling as the safest and most efficient installation method to connect the offshore intake structure to the pump station just over a quarter mile inland. Utilizing a remotely operated Herrenkenecht AVN1500 microtunnel boring machine (mTBM), this pipe jacking technique ensured efficient excavation without requiring crews inside the tunnel. Additionally, the selection of Permalok® pipe with T-7 joints allowed the system to be installed in a single pass. Incorporating two rubber O-ring gaskets into its precision-machined interface, the T-7 joint design facilitates rapid stabbing and alignment, resulting in a flush end to end connection.
Microtunneling launched from a drive shaft 65 feet deep and 42 feet wide. Soil conditions were optimal for tunnel boring, consisting of soft, fine grain sands handily removed via the spoil slurry system. Running at full capacity (three shifts per day), the Michels team efficiently installed up to 160 feet of Permalok® pipe per 24-hour period, pausing only to ensure proper alignment of the mTBM laser guidance system against laser distortion, a natural phenomenon commonly caused by atmospheric and subterranean temperature variations. Despite this challenge, the contractor’s thorough attention to detail helped lead to project success.
With the Missouri River intake structure and connecting pipe successfully installed, the microtunneling drive shaft becomes the location of the project’s intake pump station. Additional project features include the construction of a new water treatment plant, a discharge structure on the Sheyenne River, and a 167-mile water transmission pipeline capable of conveying up to 165 cfs (cubic feet per second) of water. Northwest Pipe Company has already supplied 5,950 feet of 72-inch engineered spiralweld steel pipe for the first phase of the water main construction in Foster County, North Dakota. Construction of all phases of the project is expected to be completed in 2029.
For more information on this project, visit http://www.rrvwsp.com/