The John Day Dam Hydroelectric Power is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States. The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift (110 feet) of any U.S. lock. The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4 miles (123 kilometers) up the river channel to the foot of the McNary Dam. John Day Dam is part of the Columbia River Basin system of dams.

John Day Dam hydroelectric power plant is located 28 miles (45 km) east of the city of The Dalles, Oregon, and just below the mouth of the John Day River. The closest town on the Washington side is Goldendale, 20 miles (32 km) north. The closest town on the Oregon side is Rufus, Oregon. Its crest elevation is approximately 570 feet (170 m) above sea level. It joins Sherman County, Oregon with Klickitat County, Washington, 216 miles (348 kilometers) upriver from the mouth of the Columbia near Astoria, Oregon.

Construction of the John Day Dam Hydroelectric Power began in 1958 and was completed in 1971, making it the newest dam on the lower Columbia, at a total cost of US$511 million. John Day Dam was built and is operated by the U.S. Army Corps of Engineers. The dam's power generation capacity is 2,480,000 kW (overload capacity).

Specifications of John Day Dam

  • Altitude: 266 feet (81 m) above sea level
  • Height: 183 feet (56 m)
  • Length: 7,365 feet (2,327 m)
  • Navigation lock:
    • Single-lift
    • 86 feet (26 m) wide
    • 675 feet (206 m) long
  • Powerhouse
    • Sixteen 135,000 kW units
    • Total capacity: 2,160 MW
    • Overload capacity: 2,485 MW
  • Spillway
    • Gates: 20
    • Length: 1,228 feet (374 m)
John Day Dam
Locale Sherman County, Oregon / Klickitat County, Washington
United States
Coordinates 45°42′59″N 120°41′40″W / 45.71639°N 120.69444°W / 45.71639; -120.69444
Construction began 1958
Opening date 1971
Construction cost US$511 million
Dam and spillways
Type of dam Concrete gravity, run-of-the-river
Length 2,327 m (7,635 ft)
Height 56 m (184 ft)
Impounds Columbia River
Type of spillway Service, gate-controlled
Creates Lake Umatilla
Power station
Operator(s) U.S. Army Corps of Engineers
Type Yes
Turbines 16 × 135 MW
Installed capacity 2,160 MW
Maximum capacity 2,485 MW