McNary Dam

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McNary Dam
Spillway view from the southwest, Oregon side of the Columbia River
Maintained by	U.S. Army Corps of Engineers (Operator)
Construction began	1947
Opening date	1954 (Partial Activation) 1957 (Full Activation)
Geographical Data
Coordinates	45°55′47″N, 119°17′46″W

McNary Dam is a 1.4 mile (2.2 km) long hydroelectric dam which spans the Columbia River. It joins Umatilla County, Oregon with Benton County, Washington, 292 miles (470 km) upriver from the mouth of the Columbia at Astoria, Oregon. It is operated by the U.S. Army Corps of Engineers' McNary Lock and Dam office. The dam is located a mile (1.6 km) east of the town of Umatilla, Oregon, and 8 miles (13 km) north of Hermiston, Oregon. The dam was originally planned to be named Umatilla Dam, but the Flood Control Act of 1945 renamed the dam in honor of Senator Charles L. McNary of Oregon, who had died the previous year.

The dam provides for slackwater navigation, hydroelectric power generation, recreation, wildlife habitat, and incidental irrigation. The initial phase of construction began in 1947, and was completed in 1954. Activation of all generating units was completed in 1957. Its capacity is 980 MW. There are two fish ladders for salmon and steelhead passage, one on each shore of the dam. The Washington side also has an 86 foot (26 m) wide, 683 foot (208 m) long navigation lock that lifts boats an average of 75 feet (23 m). The reservoir behind the dam, Lake Wallula, extends 64 miles (103 km) up the Columbia to the US DOE Hanford Site. It also extends up the Snake River to the Ice Harbor Dam.

This dam has a unique feature: two additional turbines whose purpose is to power the dam itself. That is, this dam is entirely self-sustaining; and if some large event caused the entire grid to go down, McNary would be key in getting it back on. These two "station service" turbines are only capable of providing about three MW, compared to the 70 MW of the other 14 turbines. These two turbines operate alternatingly to provide the dam with its energy requirements.

McNary Dam is part of the Columbia River Basin system of dams.

Stats:

• Location: 45.9298548 -119.2961275
  ( 45°55′47″N, 119°17′46″W)
• Altitude: 344 feet above sea level
• Height: 183 feet
• Length: 7,365 feet
• Navigation lock:
  • Single-lift
  • 86 feet wide
  • 683 feet long
• Powerhouse
  • Fourteen 70,000-kilowatt units
  • Total capacity: 980 Megawatts
  • Overload capacity: 1,127 MW
• Spillway
  • Gates: 22
  • Length: 1,310 feet

[edit] Gallery

Looking north, McNary Dam with lock & one fish ladder on the far (north) side of the river, spillway in the middle of the dam, earthfill embankment on the south side of the river, and the power generation station and another fish ladder between the spillway and the embankment

Plans for a second powerhouse submitted in 1986, which were cancelled in 1991

[edit] See also

• Hydroelectric dams on the Columbia River

[edit] External links

• McNary Lock & Dam @ US Army Corps of Engineers
• Maps and aerial photos Coordinates: 45.9298548° -119.2961275°
  • Street map from Google Maps, or Yahoo! Maps, or Windows Live Local
  • Satellite image from Google Maps, Windows Live Local, WikiMapia
  • Topographic map from TopoZone
  • Aerial image or topographic map from TerraServer-USA

Columbia River Dams
Bonneville • The Dalles • John Day • McNary • Priest Rapids • Wanapum • Rock Island • Rocky Reach • Wells • Chief Joseph • Grand Coulee • Keenleyside • Revelstoke • Mica