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.
Construction
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.
Transmission
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.
Turbines
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.