North Transmission Line Intertie - Segment 2

RH2 supported the City of Beaverton in advancing Segment 2 of the Northwest Transmission Line Improvement (NTLI), a secondary, seismically resilient water supply connection to the Joint Water Commission treatment plant. The project was strategically designed for construction alongside Washington County’s Walker Road Phase 3 improvements, allowing the City to align schedules, reduce disruption, and capture significant cost savings.

The project includes installation of approximately 3,200 feet of 24-inch transmission main and 3,700 feet of parallel 12- and 16-inch ductile iron distribution main, improving supply reliability for the Waterhouse area and strengthening system-wide redundancy. The pipeline is designed to withstand Cascadia subduction zone seismic events, with earthquake-resistant ductile iron pipe used at the Willow Creek crossing where lateral spreading is expected. Close coordination with County design teams allowed RH2 to deliver a highly efficient design that maximized resilience while minimizing cost and permitting complexity.