2.4 Elwha River and Tributaries Page 2.4-1
Chapter 2.4 Elwha River and Tributaries Page 2.4-1 2.4 ELWHA RIVER AND TRIBUTARIES 2.4.1 Overview The Elwha River is the largest watershed in the EMMT area and it constitutes the westernmost watershed within the planning area (Figure 2.4-1). The Elwha mainstem is approximately 45 miles long, has 100 miles of tributary streams, has a basin averaging approximately ten miles wide in an east-west direction, and drains 321 square miles of the Olympic Peninsula. Eighty-three percent of the drainage, including the upper 35 miles of the mainstem, lies within Olympic National Park, and is therefore protected from timber harvest, agriculture, and other land-use disturbances. The river flows in a northerly direction into the Strait of Juan de Fuca, entering the strait five miles west of Port Angeles. The Elwha is the fourth largest river, by drainage area, among all Olympic Peninsula streams, with a watershed area smaller only than those of the Quillayute, Queets, and Quinault rivers. Two major hydroelectric developments have altered the historic condition of the Elwha River. The Elwha Dam, built at RM 4.9 beginning in 1910, now impounds the 2.5-mile long Lake Aldwell reservoir, and the Glines Canyon Dam, built at RM 13.4, now impounds the 2.8-mile long Lake Mills reservoir. Originally built and operated to produce electricity for Port Angeles and beyond (supplying power as far away as Bremerton and Port Townsend prior to 1921), the dams have been fully allocated to supplying power to the pulp mill now operated by Nippon Paper Industries USA since the early 1920s.
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