Upper Klamath Lake

Upper Klamath Lake is a large, shallow freshwater lake east of the Cascade Range in south-central Oregon in the United States. The largest body of fresh water by surface area in Oregon, it is approximately 25mi long and 8mi wide and extends northwest from the city of Klamath Falls. It sits at an average elevation of 4140ft.In the early 20th century, most of the wetlands and marshes surrounding the lake were drained for agricultural purposes, damaging the larger habitat. The lake's water has been used to support the federal Klamath Project for irrigation by local farmers for a century. The lake depth fluctuates due to regulation of its water supply, averaging between 8to deep. The lake level is kept within 4137to above sea level to ensure a viable fishery in the lake and to protect coho salmon in the Klamath River below the lake.Upper Klamath Lake is fed by a watershed of 3768mi2 including the Williamson and Wood Rivers, and is drained by the Klamath River, which issues from the south end of the lake. The lake is connected by a short channel to the smaller Agency Lake to the north. The Upper Klamath National Wildlife Refuge has been established on land along the northern edge of the lake to preserve natural habitat.