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McNary Lock and Dam

McNary Dam
The dam is 7,365 feet long, rising approximately 183 feet above the streambed. It consists of a concrete structure with an earthfill embankment at the Oregon (south) abutment. The spillway is a concrete, gravity-type spillway dam. It is 1,310 feet long, and contains 22 vertical lift gates, each 50 feet by 51 feet. The crest is at elevation 291 feet mean sea level and is designed to pass a flood of 2,200,000 cubic feet per second.

Project Information

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Authorization
The project was authorized by the River and Harbor Act of 1945.

Progress
Construction of the McNary project began in May 1947. All power units were in operation in February 1957. No significant investments have been made to improve the efficiency of the generating units since they were installed. USACE and the Bonneville Power Administration are working together to modernize McNary’s turbines and related systems to improve power availability and hydraulic capacity while taking advantage of the technology that has become available since the dam was built to improve turbine passage for fish.

Project
The project includes McNary Dam, Lake Wallula, powerhouse, navigation lock, two fish ladders and a system of levees and pumping plants. The project provides for slackwater navigation, hydroelectric power generation, recreation, wildlife habitat and incidental irrigation.

McNary Dam
The dam is 7,365 feet long, rising approximately 183 feet above the streambed. It consists of a concrete structure with an earthfill embankment at the Oregon (south) abutment. The spillway is a concrete, gravity-type spillway dam. It is 1,310 feet long, and contains 22 vertical lift gates, each 50 feet by 51 feet. The crest is at elevation 291 feet mean sea level and is designed to pass a flood of 2,200,000 cubic feet per second.

Reservoir
Lake Wallula lies directly behind McNary Dam. It extends 64 miles upstream to the U.S. Department of Energy’s Hanford Site (about 27 miles above Pasco, Wash.), on the Columbia River. The lake also extends up the Snake River to Ice Harbor Lock and Dam. Lake Wallula has a water surface area of 38,800 acres with 242 miles of shore line.

Levees
The cities of Pasco, Kennewick, and Richland, Wash. are surrounded by 16.8 miles of levees. Drainage and groundwater levels landward of these levees are controlled by 15 pumping plants.

Generators
The powerhouse has fourteen 70,000-kilowatt hydroelectric generator units – a 980-megawatt total powerhouse capacity. One megawatt serves approximately 700 homes. At full capacity, McNary’s powerhouse can supply enough power for about 686,000 homes. During fiscal year 2011, 5.87 billion kilowatt hours of electricity were produced.

Navigation Lock
This is a single-lift lock, 86 feet wide by 683 feet long, with a 75 foot vertical lift. More than 5.08 million tons of commodities were passed through the navigation lock during 2011, consisting primarily of grains, petroleum products, fertilizer and wood products.

Fish Passage
There are two fish ladders for adult migrating salmon and steelhead to use. A new juvenile fish facility (JFF) and bypass system was completed in 1994. During 2009, about 3.8 million juvenile salmon and steelhead were collected at the JFF. About 3.3 million fish were bypassed back into the river, and about 448,833 transported for release past Bonneville Lock and Dam. In 2007, spillway weirs were installed in two spillway bays. The weirs are designed to create a surface-oriented route for juvenile salmon passage at the dam. In 2010, fish ladders were modified to accomodate lamprey passage.

Lands
The 16,908 acres of project lands surrounding the lake are utilized for public recreation purposes, wildlife habitat, wildlife mitigation and water-connected industrial development. At the present time, about 2,400 acres are leased either to state or local park agencies. The U.S. Fish and Wildlife Service leases approximately 3,500 acres of project lands as part of the McNary National Wildlife Refuge. Port districts own approximately 1,500 acres within the project boundary for industrial development. Facilities operated by commercial concessionaires or boat clubs are available at eight locations. Public boat launching facilities are available at 14 locations along the shoreline. Visitation on Lake Wallula during 2011 was about 4,164,841.

People
More than 120 Walla Walla District employees work at the McNary Project. They serve as electricians, lock operators, painters, welders,riggers, utility workers, mechanics, biologists, environmental resource specialists, park rangers, heavy equipment operators, administrative staff, engineers and maintenance workers. Together, they ensure the safe and continuous operation of the project.

Budget
During fiscal year 2011, total expenditures were $17,908,149 for the McNary Project.

References
Annual Report of the Chief of Engineers on Civil Works Activities, Fiscal Year 2011, Department of the Army Corps of Engineers, Extract Report of the Walla Walla District.

General
River Mile - 292
Drainage area - 214,000 sq miles
Normal hydraulic height - 75 ft
Maximum structural height - 220 ft
Overall length at crest - 7,300 ft

Discharge:
Minimum of record – 30,000 cfs
Mean annual – 191,000 cfs
Maximum of record (1894) – 1,150,000 cfs
Spillway design flood – 2,200,000 cfs

First power on line - December 1953
Concrete - 1,861,000 cubic yards
Earth - 2,937,000 cubic yards

Estimated Cost
1 January 1977 - $304,700,000

Lake
Elevations:
Maximum – 356.5
Normal operating range – 340-335

Length - 61.6 miles
Area at normal pool - 37,000 acres

Relocations:
Railroad – 80.5 miles
State highway and county roads – 42.5 miles
Power and communications lines – 57 miles

Drawdown for power - 5 ft
Capacity, power pondage - 185,000 acre-ft
Revetted levees - 17 miles
Length of shoreline - 242 miles

Navigation Lock
Type - Single lift
Normal lift - 75 ft
Clear width - 86 ft
Net clear length - 683 ft
Minimum depth over sills - 15 ft
Upstream gate - Mite
Downstream gate - Arch
Guide wall lengths:
Upstream - 1,417 ft
Downstream - 1,520 ft

Spillway
Deck elevation - 361
Crest elevation - 291
Overall length - 1,310 ft

Control gates:
Number - 22
Type - Vertical lift
Size, width by height above crest - 50' x 51' ft

Maximum design capacity - 2,200,000 cfs
Deck cranes, each, 2, capacity - 200 tons

Powerhouse
Number of units - 14
Nameplate rating:
Each - 70,000 kilowatts
Total - 980,000 kilowatts

Intake deck elevation - 361
Tailrace deck elevation - 287
Unit spacing - 86 ft
Length assembly bay - 134 ft
Length overall - 1,422 ft

Turbines:
Type - Kaplan
Runner diameter – 280 in
Revolutions – 85.7 per min
Horsepower rating - 95,400

Crane capacities:
Intake deck – 140 tons
Bridge, powerhouse interior, each, 2 – 350 tons
Tailrace deck – 30 tons

Abutments
Abutments Rock fill with impervious core

Fish Facilities
Number of ladders - 2
Ladder slopes - 1 on 20
Ladder widths - 30 ft

Contact Us

McNary Lock and Dam
82790 Devore Road
PO Box 1230
Umatilla, OR 97882-1230
Phone: 541-922-3211