Tualatin Valley Water District, Willamette Water Supply Program (WWSP) Raw Water Facilities Evaluation

GRI completed geotechnical and seismic engineering to support the WWSP evaluate the existing infrastructure and proposed improvements at the Raw Water Facility located on the Willamette River. Key aspects of the project included evaluation of the liquefaction and lateral spreading potential to impact operation of the existing intake facility and caisson pump structure. This work included an extensive exploration program to provide input parameters for the two-dimensional numerical model developed in Fast Lagrangian Analysis of Continua (FLAC). GRI also completed site-specific cyclic direct simple shear testing to calibrate the numerical model and better estimate seismic hazards at the site. The evaluation of new infrastructure included a new 72-inch-diameter pipeline, surge tanks, electrical facilities, and a trenchless crossing of the creek entering the site. The project involved working with the owner to develop program-specific design criteria to meet the program’s stringent performance standards.

Location: Wilsonville, Oregon

Owner: Willamette Water Supply

Market Sector: Water & Environment