Upper Klamath Lake
|Upper Klamath Lake|
|Location||Klamath County, Oregon, USA|
|Primary inflows||Williamson River|
|Primary outflows||Link River|
|Basin countries||United States|
|Max. length||20 mi (32 km)|
|Max. width||8 mi (12.9 km)|
|Surface elevation||4140 ft (1262 m)|
Upper Klamath Lake (sometimes called Klamath Lake) (Klamath: ?ews, "lake" ) is a large, shallow freshwater lake east of the Cascade Range in south central Oregon in the United States. The largest freshwater body by surface area in Oregon, it is approximately 20 mi (32 km) long and 8 mi (12.9 km) wide and extends northwest from the city of Klamath Falls. It sits at an elevation of 4140 ft (1262 m).
In the early 20th century, most of the wetlands and marshes were drained for agricultural purposes, damaging the larger habitat, and lake waters were used to support federal irrigation projects on behalf of local farmers. The lake depth fluctuates due to regulation of its water supply, ranging from 8 ft (2.5 m) to 60 feet (18 m) deep at average levels. The lake level is kept within 1261 to 1264 m above sea level to ensure life for fish in the lake and to protect salmon in the Klamath River below the lake. The lake is fed by several streams, including the Williamson River and is drained by the Link River, which issues from the south end of the lake. It 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.
Since 1917, the water level in the lake has been regulated by the United States Bureau of Reclamation (BOR)'s Link River Dam as part of the Klamath Reclamation Project, to supply irrigation waters to support agriculture in the upper Klamath Basin.
Prior to the 20th century, the lake was surrounded by widespread marshes and wetlands, which supported fish, birds and wildlife, as well as protecting water quality in the lake. Much of these important habitats were drained to be converted to cultivated farmland, as farmers did not understand the value of the wetlands for the environment. The lake is naturally eutrophic, due to a high concentration of nutrients. In the 20th century, the augmentation of nutrients by agricultural runoff from the surrounding farming valley has caused the lake to become hypereutrophic, resulting in blue-green algae blooms over the lake ( largely Microcystis aeruginosa and Aphanizomenon flos-aquae). The algae blooms turn the water an opaque green in the summer and reduce the opportunity for recreational uses of the lake. State standards for dissolved oxygen are routinely violated, meaning that fish are endangered.
The US Fish and Wildlife Service (FWS) monitors water levels and quality, as it is responsible for protecting and maintaining fish populations in the lake and salmon in the Klamath River. In 1988, the FWS placed the Lost River sucker and the shortnose sucker (Catostomidae) on the federal endangered species list; the numbers of the two formerly abundant Upper Klamath Lake fish species had sharply fallen due to the decline in water quality. As a result, the government abandoned a planned dredging project, which would have further damaged the water quality. The project was to dredge a deeper navigation channel from one end of the lake to the other; it was planned between several government agencies and Aqua Farm's Inc.
A drought in the summer of 2001 heightened environmental concerns about the lake. The BOR stopped withdrawing irrigation water for the Klamath Project in order to protect the sucker population. The farming community protested, as they depended on a supply of lake waters for their operations. As of 2003, the FWS was monitoring the lake regularly due to water shortfalls, which endangered both fish in the lake and salmon in the Klamath River. The future uses of Klamath Lake are of national interest because of competing claims between farmers' property rights (supported by federal subsidies and programs) and larger environmental goals.
See also 
|Wikimedia Commons has media related to: Klamath Lake|
- USGS: Upper Klamath Lake nutrient study
- Oregon Lakes: Upper Klamath Lake
- Klamath Waters Digital Library