Elwha River Water Treatment Facilities

Olympic National Park, Port Angeles, Washington

Part of the overall Elwha River Restoration Project to return the river to its original natural state for spawning Chinook salmon, this venture included four component projects: Elwha River Levee Improvements, Elwha Surface Water Intake, Elwha Water Treatment Plant, and the Crown Z Road Improvements. The Elwha Surface Water Intake (ESWI) and area flood protection encompassed new levee construction, modification to the existing fish hatchery, and in-water modifications, as well as the Lower Crown Z Road reconfiguration and rebuild. Downstream from the ESWI, the Elwha Water Treatment Plant (EWTP) treats water from the ESWI for use in industrial, municipal, and fisheries applications by removing suspended sediments. The EWTP consisted of an 80 CFS Influent Pump Station, four (4) 110-ft. diameter Sedimentation Tanks, two Slurry Pump Houses, and seven Mix Tanks with Chemical Feed Building and Storage. The Effluent Distribution Structure supplies multiple end water users. Watts-Delhur completed three seasons of in-water work in one season in a remote location and maintained a minimal impact presence in an environmentally sensitive environment.