Warm Springs Reservoir

Warm Springs Reservoir is a reservoir on the boundary between Harney and Malheur counties in the U.S. state of Oregon. It is located 13 miles (21 km) southwest of Juntura at an elevation of 3,406 feet (1,038 m). The lake's primary inflow and outflow are both the Malheur River.[2][4]

Warm Springs Reservoir
Warm Springs Dam and Reservoir
Warm Springs Reservoir Show map of Oregon Warm Springs Reservoir Show map of the United States
Location	Harney / Malheur counties, Oregon, United States
Coordinates	43°35′08″N 118°12′32″W[1]
Type	Reservoir
Primary inflows	Malheur River
Primary outflows	Malheur River
Catchment area	1,059.5 sq mi (2,744.1 km2)[1]
Basin countries	United States
Built	1919
Max. length	8.5 mi (14 km)[2]
Max. width	1.3 mi (2.1 km)[2]
Surface area	4,194 acres (1,697 ha)[2]
Average depth	68 ft (21 m)[3]
Max. depth	140 ft (42.7 m)[3]
Water volume	169,714 acre⋅ft (209,339 dam3)[2]
Residence time	2.2 years[3]
Shore length1	34.5 mi (55.5 km)[3]
Surface elevation	3,406 ft (1,038 m)[2]
1 Shore length is not a well-defined measure.

The 106-foot (32.3 m) tall and 469-foot (143 m) long thin-arch concrete Warm Springs Dam was built from 1918 to 1919 by the Warm Springs Irrigation District, and was later modified in 1930 and 1939 with the help of the United States Bureau of Reclamation.[2][5][6] It was constructed from 19,500 cubic yards (14,900 m³) of material on top of a series of olivine basalt lava flows.[4][6] The resultant 8.5-by-1.3-mile (14 by 2.1 km) reservoir has a maximum area of 4,194 acres (1,697 ha), a maximum volume of 169,714 acre feet (209,339 dam³),[2] and a maximum depth of 140 feet (42.7 m).[3] It has a shore length of about 34.5 miles (55.5 km) and a residence time of about 2.2 years.[3]

Warm Springs Reservoir's watershed covers approximately 1,059.5 square miles (2,744.1 km²) of eastern Oregon. It receives an average precipitation of 17.5 inches (444 mm). As of the 2000 Census, there were 157 people living within the watershed's boundaries.[1]

The predominant wildlife in the region is mule deer and various waterfowl. Bass, bluegill, and rainbow trout are the main fish found in the reservoir.[7] The reservoir is classified as eutrophic, with a transparency of about 3.3 feet (1.0 m).[3]