river rising in Upper Klamath Lake just above Klamath Falls, Ore., U.S. It flows south for 1.25 miles (2 km) as the Link River to Lake Ewauna, where it emerges as the Klamath River, and continues generally southwesterly 250 miles (400 km) through the Klamath Mountains in California to the Pacific Ocean near Requa, Calif. The upstream basin section has extensive irrigation developments. Copco No. 1 Dam (1922) in northern California is used for power. Lower Klamath Lake, dried up when its Klamath River connection was closed in 1917, has been developed as a wildlife refuge and for agricultural use. Chief tributaries of the Klamath are the Shasta, which joins it near Yreka, and the Trinity, joining it near Weitchpec.