Rocky Reach Dam

The Rocky Reach Hydro Project is located in north central Washington state on the Columbia River, about seven miles upstream from the city of Wenatchee. By river, the dam is 215 miles below the Canadian border, and 473 miles above the mouth of the Columbia at Astoria, Ore.

People throughout the Northwest benefit from clean, renewable energy produced at Rocky Reach. The project is also nationally recognized for efforts to protect the environment. A first-of-its-kind juvenile fish bypass system was completed in 2003 to help young salmon and steelhead on their way to the ocean. A major powerhouse upgrade started in 1995 includes new turbines that are more fish friendly. Improvements to turbines and generators are also designed to improve efficiency and reliability.

Quick facts about the Rocky Reach Hydro Project:

  • Length of dam: 1694'
  • Height of dam: 125'
  • 11 generators
  • Generator nameplate capacity is 1,349 megawatts
  • Dam contains 12 spillway gates
  • Original construction started in 1956
  • Commercial operation 1961 (seven generators)
  • Four generators added in 1969 - 71
  • Project license expires in the year 2052

Hydro Project Background

The Rocky Reach site has long been recognized for its hydroelectric potential. The U.S. Army Corps of Engineers first considered the site in its 1934 "308 Report." In the 1950s, the site became the focus of extensive studies by the PUD. Geological contour maps were studied, construction costs were estimated, and lengthy computations on such things as the forces and stresses a dam would have on the surrounding area were made.  

The original site selected for the Rocky Reach Project by the U.S. Army Corps of Engineers was about one mile upriver from where the dam is today. The present site was found to have superior rock for anchoring the dam, and the river channel is narrower at that location.  

Powerhouse Rehabilitation

In 2006, the PUD completed a major upgrade of the powerhouse. Starting in 1995, the District installed new adjustable-blade turbine runners on all 11 generating units and also rehabilitated unit generators. The work improves the efficiency and reliability of the hydro plant. The end result is more power generation, higher revenues and lower maintenance costs. In addition, the new turbine runners are "fish friendly," designed to reduce juvenile salmon and steelhead mortality.  


The Rocky Reach Project was developed over a period of about 15 years. Construction of the dam and original powerhouse with seven generating units began in 1956 for the purpose of power production and flood control. The addition of four more units began in 1969 after ratification of the Columbia River Treaty between the United States and Canada. The additional units were installed primarily to make use of stored water released from reservoirs in Canada and the Libby Dam reservoir in Montana.  

Development History

The District received a preliminary permit for the Project from the Federal Power Commission (FPC) on Aug. 10, 1954. An application to construct and operate the dam was filed with the same agency on Jan. 13, 1956. The Federal Power Commission issued a license to build the Project six months later, on July 12, 1956. Construction of the dam and original powerhouse began on Oct. 2, 1956 under the supervision of the District's engineering design firm, Stone and Webster Engineering Corporation. The immediate task was the installation of cofferdams to seal off the area designated for the spillway from the river flow during low water. Following spillway construction, the powerhouse was built. A total of 3.3 million cubic yards of dirt and rock were moved during the five-year initial construction. Employment peaked at 2,184 in July 1959. The initial seven generating units were placed in commercial operation on Nov. 1, 1961, six months ahead of schedule.  

On Sept. 1, 1966, the District filed an application with the Federal Power Commission to amend the Project License to add four generating units. The FPC issued the license amendment May 23, 1968. The second phase of construction began April 22, 1969, and was completed Dec. 1, 1971. The expansion work increased the power plant's generating capability by 60 percent, from 815,000 kilowatts to 1.287 million kilowatts. The generator nameplate capacity was increased to 1,300 megawatts after the 1995 to 2006 rehabilitation project

Construction Costs

The Project was financed through the sale of revenue bonds. A revenue bond is a pledge of future revenues generated by the project to repay debt. No tax money was used. The original project, which cost $273.1 million, was financed with a $23.1 million bond issue completed in November 1956 to allow for an early construction start. It was followed by a completion bond issue of $250 million in January 1958.  

Included in the Project costs were the relocation of a rail line, highways, land acquisition, relocation of the Town of Entiat, and financing. The subsequent powerhouse expansion and addition of four generating units completed in 1971 were financed by a revenue bond issue of $40 million, sold in July 1968.  


Power from the Rocky Reach Project is delivered to the District's Distribution System at 115,000 volts. Other 230,000-volt transmission lines deliver energy to the Project's power purchasers. Power also flows into the regional grid of the Bonneville Power Administration.  


The hydraulic turbines consist of huge water wheels that resemble ship propellers. They are turned by the water flow and connected to the electricity-producing generators by large steel shafts. All 11 units at the Rocky Reach Project are equipped with adjustable blade turbines. Their design allows the turbines to maintain maximum operating capacity and efficiency despite variations in the river flow and generator output.

Spillway Gates

The crest of the reservoir can be regulated by 12 spillway gates, which open individually and allow water to pass through separate spillway bays. The gates pass water seasonally that is surplus to power generation needs, or as required for assisting fish in their downstream migration.  

Hours & Free Admission

Open Tuesday - Sunday, 9:30 a.m. - 9 p.m.

Rocky Reach Park and Playground now open year-round!
Open daily, 9 a.m. to 9 p.m

5000 State Hwy 97A
Wenatchee, WA 98801
(509) 663-7522
Get directions