McNARY LOCK AND DAM--LAKE WALLULA
(150 dpi) (75 dpi)

Columbia River, Washington and Oregon

CWIS: 10920

AUTHORIZATION: Authorized by Section 2 of the River and Harbor Act of 1945 (Public Law 79-14, 79th Congress, 1st Session), and approved 2 March 1945 in accordance with House Document 704, 75th Congress, 3d Session. The project was originally called Umatilla Dam, but the River and Harbor Act of 1945 also renamed the dam in honor of the late Senator Charles L. McNary. Recreation was authorized in the River and Harbor Act of 1944 (Public Law 78-534), as amended. A second powerhouse was authorized by the Water Resources Development Act of 1986 (Public Law 99-662, 99th Congress, 2d Session), and approved November 17, 1986, as specified by the report of the Chief of Engineers dated June 24, 1981. The second powerhouse was deauthorized on November 16,1991, in accordance with Section 1001 of the Water Resource Development Act of 1986.

PROJECT: The project includes McNary Dam (photo), Lake Wallula, powerhouse, navigation lock, two fish ladders, appurtenant facilities, 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 (150 dpi) (75 dpi): The dam is 7,365 feet long, and rises 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 mean sea level, which is designed to pass a design flood of 2,200,000 cubic feet per second. The dam is located at River Mile 292, above the mouth, and raises the normal water surface about 85 feet.

Lake Wallula: Lake Walllula 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, Washington), 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. The lake has a normal operating range between 340 and 335 mean sea level.

Powerhouse: The McNary Powerhouse has 14 units of 70,000 kilowatts each, for a total capacity of 980,000 kilowatts. Power generation through September 1996 was 253.49 billion kilowatts hours.

Navigation lock: The lock is a single lift type, with clear plan dimensions of 86 feet wide and 683 feet long, and a 15-foot minimum depth over the sills. The vertical lifts average 75 feet. The lock is located on the Washington side.

Fish Passage: There are two fish ladders for migratory fish passage, one on each shore of the dam; and a powerhouse fish collection system.

Levees: The cities of Pasco, Kennewick, and Richland, Washington (locally known as the Tri-Cities), are protected by 16.8 miles of levees. Drainage and groundwater levels landward of these levees are controlled by 15 pumping plants. The section of the levee generally has a top elevation of 8 feet above the calculated backwater stage for maximum flood.

Lands: The 16,908 acres of project lands surrounding the lake are utilized for public recreational purposes, wildlife habitat, wildlife mitigation and water-connected industrial development. At the present time, approximately 2,400 acres are licensed 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 17 locations along the shore line.

LOCAL COOPERATION: None required.

PROGRESS: The initial project is complete. Construction was initiated in May 1947, and was completed in 1954. All power units were in operation in February 1957. Alterations of railroad bridges on the Columbia and Snake Rivers to reduce navigation hazards were found to be necessary, and Burlington Northern (formerly Northern Pacific) completed modifications to Bridge No. 3 over the Snake River in December 1971. The Corps and Union Pacific could not agree on modifications to their bridge, and negotiations were turned over to the U.S. Coast Guard in 1970. Agreement was reached, and the modification of the Union Pacific Railroad bridge was completed in August 1977. The Water Resource Development Act of 1986 authorized funds for the study of a second powerhouse on the Oregon side. The plan included a second powerhouse, fish and wildlife mitigation, and improvement to the levees in the Tri-Cities (Pasco, Kennewick, and Richland, Washington). The project was deauthorized in 1991. The Water Resource Development Act of 1990 authorized the Corps to construct the levee beautification portion of the project, and directed the Secretary of the Army to complete a feasibility study regarding the lowering of the levees. A reconnaissance study, completed in May 1992, concluded that there was no Federal interest in the project.

The existing navigation channel was intermittently excavated for 8.8 miles to provide the authorized channel depth of 14 feet below minimum regulated flow for navigation. Lake Wallula, in the past, has been operated above elevation 337, but the increased demand for peaking power now makes it necessary to use the total authorized poundage.

COST: Total Federal expenditures through September 1996 have been $360,103,405 for new work, and $231,390,880 for operation and maintenance.

• McNary Lock and Dam, Lake Wallula, Structural Details (150 dpi) (75 dpi)
• McNary Lock and Dam, Lake Wallula, Deauthorized Second Powerhouse Dam Vicinity (150 dpi) (75 dpi)
• McNary Lock and Dam, Lake Wallula, Deauthorized Second Powerhouse Structural Details (150 dpi) (75 dpi)