The Elwha River originates within the heart of the Olympic Mountains and flows for approximately 45 miles until it reaches the Strait of Juan de Fuca. The majority of the Elwha River is contained within the boundaries of Olympic National Park (ONP), and is practically pristine until it departs the Park.
Two mainstem dams, built without fish passage facilities, are being removed beginning in the fall of 2011. Elwha Dam located at river mile 4.9 has been completed removed and has exposed the former Aldwell reservoir. Glines Canyon Dam located at river mile 13.4 is expected to be removed by the spring of 2013.
Aldwell reservoir was formed when Elwha Dam was constructed in 1913, while Mills reservoir was formed following the completion of Glines Canyon Dam in 1925. Both reservoirs were extensively logged prior to dam construction. Over the last 80-100 years an estimated 24 million cubic yards of sediment has accumulated in the reservoirs. Following dam removal, a free flowing Elwha River will reestablish. Construction of hydroelectric dams, without fish passage facilities, has limited anadromous fish to the lower five miles of the watershed and has effectively truncated the delivery of sediment and wood (necessary for habitat forming processes). As a result anadromous fish populations of the Elwha River have been dramatically impacted. The Elwha River Ecosystem and Fisheries Restoration Act (PL 102-94) is the federal law that has guided planning and implementation of dam removal, fish and ecosystem restoration. A fisheries restoration plan (Ward et al. 2008) and revegetation plan (Chenoweth et al. 2011) guide restoration activities. Together with dam removal, these efforts guide what is the largest watershed restoration effort conducted to date in the Pacific Northwest, and the second largest restoration project ever undertaken by the National Park Service.