Basin countries United States Surface elevation 892 m Width 1.6 km | Primary inflows Catchment area 187 mi² (484 km²) Max. length 6 mi (9.7 km) Length 9.7 km Outflow location Tieton River | |
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Rimrock Lake is a lake along the course of the Tieton River, in Yakima County, Washington state, US.
Map of Rimrock Lake, Washington 98937, USA
The lake is used as a storage reservoir for the Yakima Project, an irrigation project run by the United States Bureau of Reclamation. An impoundment of the Tieton River, Rimrock Lake's capacity and discharge is controlled by Tieton Dam, a 319-foot (97 m) high structure built in 1925. Rimrock Lake's active capacity is 198,000 acre feet (244,000,000 m3).
Upstream from the lake, the Tieton River is impounded by Clear Creek Dam, another element of the Yakima Project. About 8 miles (13 km) downstream from Rimrock Lake the Tieton River is tapped by the Tieton Diversion Dam, supplying water to the Tieton Main Canal. The canal supplies irrigation water to the Tieton Division of the Yakima Project, with excess and agricultural runoff draining into Ahtanum Creek, west of Yakima.