Dependence of Flow and Transport through the Williamson River Delta, Upper Klamath Lake, Oregon, on Wind, River Inflow, and Lake Elevation.

摘要

Upper Klamath and Agency Lakes in south-central Oregon constitute a shallow lake system with a large surface area (average depth 2.8 m and surface area 230 km2). As such, the currents in the system are primarily wind-driven. The lakes are situated in the Klamath structural graben, and under prevailing conditions, the westerly to northwesterly winds that blow over the northern part of Upper Klamath Lake are largely constrained by the surrounding topography to a north-northwesterly direction over the lower two-thirds of the lake. The resulting circulation pattern is a clockwise gyre around Upper Klamath Lake (Wood and others, 2006). The largest tributary to the system is the Williamson River, which enters Upper Klamath Lake along the northern shoreline; a smaller tributary is the Wood River, which enters at the northern end of Agency Lake. Lake surface elevations are regulated by the Link River Dam at the southern end of the lake, which is operated by the Bureau of Reclamation. During the summer months, lake elevation declines due to a combination of reduced inflows, evaporation, and downstream diversions to meet irrigation demands and instream flow requirements of the National Marine Fisheries Service for coho salmon in the Klamath River. As a result, in most years lake elevation declines by about 1 m (3.3 ft) between June 1 and September 1.