Hydroelectricity in the Columbia River Basin

Not long after Northwest pioneers established the first cities in the region, they began to capture the power of falling water to make electricity for their homes and industries.

They were the first to tap the great hydroelectric potential of the Columbia River Basin, a region that includes parts of Washington, Oregon, Idaho, Montana, Wyoming, Utah, Nevada, and British Columbia. It is an area considerably larger than the country of France.

Today, the Northwest relies on hydropower for about two-thirds of its electricity, and 40 percent of all U.S. hydropower comes from the Columbia system.

Willamette Falls Power Station, 1889 Oregon Historical Society photograph (click to enlarge)

The T.W. Sullivan Dam at Willamette Falls in Oregon City was the first hydroelectric dam in the lower Columbia Basin. It was built in 1888, 37 years after the founding of Portland.

Washington Water Power Company built the Monroe Street Dam on the Spokane River in downtown Spokane in 1896, just 15 years after the city of Spokane Falls was platted and seven years after fire destroyed 32 blocks of the downtown business district. In Spokane, as elsewhere in the Northwest, hydroelectric power and progress were linked.

The city of Idaho Falls built the first hydroelectric dam on the Snake River in 1904. The nearby Minidoka Dam, a federal project, followed in 1906. Development of other dams in the Columbia and Snake basins proceeded at a rather slow pace during the early 1900s.

Hydroelectric development in the basin really began in earnest in the 1930s with the damming of the mainstem of the Columbia and Snake rivers. The first, in 1933, was Rock Island Dam near Wenatchee. Bonneville Dam followed in 1938. Construction of dams on the Columbia and Snake rivers continued into the 1970s, with most of the development occurring between 1950 and 1970.

Today there are 58 dams built exclusively for hydropower in the Columbia River Basin, and hydropower now supplies roughly 60 percent of the electricity used in the Northwest. Seventy-four percent of the power generating capacity in the four states is hydropower, 32,950 megawatts of the 44,350 megawatts total. The mainstem of the Snake River not only has more dams than any other tributary in the Columbia Basin, it has the largest dams of any tributary in the basin.

In addition to the 58 hydropower dams, there are 78 multiple purpose projects in the basin that include hydropower production. Other benefits provided by many of the dams include navigation for large barges; irrigation to farms in drier areas; launching areas for recreational activities; and flood control.

While the dams brought tremendous advantages, they also posed problems to the region. They are obvious physical barriers to the salmon and steelhead that hatch in the tributaries and migrate through the mainstem Snake and Columbia to the ocean as juveniles, and back home to spawn as adults.

In 1982, at the behest of Congress, the Northwest Power and Conservation Council adopted the Columbia River Basin Fish and Wildlife Program. It is designed to reverse some of the damage to fish and wildlife caused by hydropower and to increase protection in the future.

The Council's program calls for permanent solutions to improve fish survival at dams, such as bypass systems to channel juvenile fish migrating downstream away from the dams' turbines.

Bypass systems are in place at dams downstream of Chief Joseph Dam on the Columbia and Hells Canyon Dam on the Snake. Those two dams do not have fish passage facilities.

This map identifies the United States dams along the mainstem of the Columbia and Snake rivers. In addition to historical information, the map describes the dams and the types of fish protection facilities, including those for downstream and upstream fish passage.

Dams (starting at mouth of Columbia, moving upriver)

	Bonneville Dam Location: Bonneville, Oregon Columbia River mile: 146.1 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1938 (Powerhouse I: 10 turbine units); 1982 (Powerhouse II: 8 turbine units and 4 fishways) Generating capacity: 1,050 megawatts Juvenile fish passage facilities: Screens on all turbine units with a bypass system to tailwater. Adult fish passage facilities: Fish ladders with fish counting stations at both powerhouses. Additional notes: A juvenile bypass was completed in 1999 for powerhouse II.
	The Dalles Dam Location: The Dalles, Oregon Columbia River mile: 191.5 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1960 (14 turbine units); 1973 (8 turbine units) Generating capacity: 1,780 megawatts Juvenile fish passage facilities: Ice and trash sluiceway Adult fish passage facilities: Two fish ladders with fish counting stations Additional notes: Surface bypass system studies are ongoing at this project; however, spill and the ice and trash sluiceway will continue to be the primary juvenile passage routes
	John Day Dam Location: Rufus, Oregon Columbia River mile: 215.6 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1971 (16 turbine units) Generating capacity: 2,1609 megawatts Juvenile fish passage facilities: Screens on all turbines with bypass system to tailwater Adult fish passage facilities: Two fish ladders with fish counting stations Additional notes: Between 1985 and 1987, the Corps installed screens in all powerhouse units
	McNary Dam Location: Umatilla, Oregon Columbia River mile: 292 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1957 (14 turbine units) Generating capacity: 980 megawatts Juvenile fish passage facilities: Screens on all units; bypass system to tailwater; fish collection and transportation facilities; fish run monitoring station Adult fish passage facilities: Two fish ladders with fish counting stations and adult PIT tag detection were installed in 2002 Additional notes: McNary’s juvenile fish bypass system was completed in 1981, upgraded in 1994, and longer screens were installed in 1997.
	Priest Rapids Dam Location: Near Mattawa, Washington Columbia River mile: 397.1 Operator: Grant County Public Utility District No. 2 Type: Run of river dam and reservoir Completed: 1961 (10 turbine units) Generating capacity: 955.6 megawatts Juvenile fish passage facilities: Spill and turbines provide good survival past the dam; flow management protects fall chinook in the Hanford Reach Adult fish passage facilities: Two fish ladders; fish counting and trapping facilities Additional notes: Grant County PUD’s relicensing studies identified new surface flow bypass systems, turbine passage improvements, and habitat and hatchery programs to offset losses
	Wanapum Dam Location: Near Beverly, Washington Columbia River mile: 415.8 Operator: Grant County Public Utility District No. 2 Type: Run of river dam and reservoir Completed: 1964 (10 turbine units) Generating capacity: 1,038 megawatts Juvenile fish passage facilities: Spillway deflectors and top spill bulkhead installed Adult fish passage facilities: Two fish ladders with video fish counting facilities Additional notes: Grant County PUD’s relicensing studies identified new surface flow bypass systems; turbine passage improvements; and habitat and hatchery programs to offset unavoidable losses
	Rock Island Dam Location: Wenatchee, Washington Columbia River mile: 453.4 Operator: Chelan County Public Utility District No. 1 Type: Run of river dam and reservoir Completed: 1932 (Powerhouse I: 4 turbine units and house unit); 1953 (Powerhouse I: 6 additional turbine units); 1979 (Powerhouse II: 8 turbine units) Generating capacity: 624 megawatts Juvenile fish passage facilities: Gatewell bypass system with no screens at Powerhouse II. In addition, Chelan County PUD is evaluating a notched spillgate for providing downstream passage at the spillway. Adult fish passage facilities: Three fish ladders with counting stations Additional notes: Rock Island was the first dam built on the mainstem Columbia River. Spill is an integral part of the long-term plan for safely providing fish passage at the project.
	Rocky Reach Dam Location: Wenatchee, Washington Columbia River mile: 473.7 Operator: Chelan County Public Utility District No. 1 Type: Run of river dam and reservoir Completed: 1961 (7 turbine units); 1971 (4 additional units) Generating capacity: 1,280 megawatts Juvenile fish passage facilities: Currently a bypass system with screens on two units and a surface collection system in the forebay cul-de-sac pass fish to a monitoring facility and the tailrace; spill is also provided if needed. Adult fish passage facilities: Fish ladder with fish counting station
	Wells Dam Location: Azwell, Washington Columbia River mile: 515.8 Operator: Douglas County Public Utility District No. 1 Type: Run of river dam and reservoir Completed: 1967 (10 turbine units) Generating capacity: 774 megawatts Juvenile fish passage facilities: Wells Dam has a unique spillbay design which lies over the turbine intakes. The spillway was modified in 1991 to provide a bypass route for juvenile migrants. Adult fish passage facilities: Two fish ladders (one with trapping facility). Adult PIT-tag detectors were evaluated in 2002, determined to be 100 percent efficient, and were installed. Additional notes: The unique hydrocombine design of Wells Dam enables the spillway to function as an extremely efficient fish bypass system
	Chief Joseph Dam Location: Bridgeport, Washington Columbia River mile: 545.1 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1961 (16 turbine units); 1979 (11 turbine units) Generating capacity: 2,069 megawatts Fish passage facilities: (none) Additional notes: Chief Joseph and Grand Coulee dams lack any fish passage facilities and thus permanently block anadromous fish from the upper Columbia River Basin
	Grand Coulee Dam Location: Grand Coulee, Washington Columbia River mile: 596.6 Operator: U.S. Bureau of Reclamation Type: Dam and storage, reservoir, pumped storage reservoir Completed: 1941 (18 turbine units); 1982 ( 6 turbine units) Generating capacity: 6,620 megawatts Fish passage facilities: (none) Additional notes: See Chief Joseph Dam
	Libby Dam Location: River Mile 221.9 on the Kootenai (from the confluence with the Columbia River) Kootenai River mile: 221.9 Operator: U.S. Army Corps of Engineers Type: Dam and storage, reservoir Completed: 1973 Generating capacity: 525 megawatts Fish passage facilities: (none) Additional notes: Libby Dam is a major upriver storage dam for the Columbia River hydropower system
	Hungry Horse Dam Location: South Fork, Flathead River above Flathead Lake Columbia River mile: na Operator: U.S. Bureau of Reclamation Type: Dam and storage, reservoir Completed: 1953 Generating capacity: 428 megawatts (after renovations in progress) Fish passage facilities: (none) Additional notes: Hungry Horse Dam is the most upstream major storage project in the United States for the Columbia River hydroelectric system
	Ice Harbor Dam Location: Pasco, Washington Snake River mile: 9.7 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1962 (3 turbine units); 1976 (3 turbine units) Generating capacity: 603 megawatts Juvenile fish passage facilities: Intake screen bypass system was completed in 1993; spill is also provided Adult fish passage facilities: Two fish ladders with fish counting stations
	Lower Monumental Dam Location: Kahlotus, Washington Snake River mile: 41.6 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1970 (3 turbine units); 1978 (3 turbine units) Generating capacity: 810 megawatts Juvenile fish passage facilities: Intake screen bypass system completed in 1992; collection and transport facilities; spill is also provided during the spring Adult fish passage facilities: Two Fish ladders
	Little Goose Dam Location: Starbuck, Washington Snake River mile: 70.3 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1970 (3 turbine units); 1978 (3 turbine units) Generating capacity: 810 megawatts Juvenile fish passage facilities: Extended screens on all units with bypass system to tailwater; collection and transportation facilities; spill is provided in the spring Adult fish passage facilities: Fish ladder
	Lower Granite Dam Location: Almota, Washington Snake River mile: 107.5 Operator: U.S. Army Corps of Engineers Type: Run of river dam and reservoir Completed: 1975 (3 turbine units); 1978 (3 turbine units) Generating capacity: 810 megawatts Juvenile fish passage facilities: Extended screens on all units with bypass system to tailwater; collection and transportation facilities; fish passage monitoring facility; spill is provided in the spring Adult fish passage facilities: Fish ladder, monitoring, and trap facilities
	Hells Canyon Dam Location: Oxbow, Oregon Snake River mile: 247 Operator: Idaho Power Company Type: Run of river dam and reservoir Completed: 1967 (3 turbine units) Generating capacity: 450 megawatts Fish passage facilities: (none) Additional notes: The Hells Canyon complex (Hells Canyon, Oxbow, and Brownlee projects) permanently blocks salmon from the upper Snake River Basin
	Oxbow Dam Location: Oxbow, Oregon Snake River mile: 273 Operator: Idaho Power Company Type: Run of river dam and reservoir Completed: 1961 (4 turbine units); 1978 (3 turbine units) Generating capacity: 220 megawatts Fish passage facilities: (none) Additional notes: See Hells Canyon Dam
	Brownlee Dam Location: Cambridge, Idaho Snake River mile: 285 Operator: Idaho Power Company Type: Dam and storage reservoir Completed: 1959 (4 turbine units); 1983 (1 turbine unit) Generating capacity: 675 megawatts Fish passage facilities: (none) Additional notes: Brownlee Reservoir is the major storage reservoir in the Hells Canyon complex
	Boundary Dam Location: Near Metaline Falls, Washington Pend Oreille River mile: 17 Operator: City of Seattle (City Light) Type: Dam and storage reservoir Completed: 1967 (4 units); 1985 (2 units) Generating capacity: 1,024 megawatts Fish passage facilities: (none)
	Dworshak Dam Location: Ahsahka, Idaho Clearwater River (North Fork) mile: 1.9 (from confluence with the Snake River) Operator: U.S. Army Corps of Engineers Type: Dam and storage reservoir Completed: 1973 (3 turbine units) Generating capacity: 400 megawatts Fish passage facilities: (none) Additional notes: Dworshak Dam permanently blocks salmon and steelhead from the North Fork Clearwater River

Glossary

Do bypass, spill, spillbay, tail race, forebay, etc., have you confused? Here’s a quick glossary.

attraction:  Water flows designed to draw fish toward ladders or other bypass systems.

bypass system, bypass channel:  A structure in a dam that provides a route for fish to move through or around the dam without going through the turbine units.  The bypass channel is the part of a system that includes a conduit built into the dam to pass fish.

drawdown:  Releasing water from a hydroelectric project to lower the reservoir elevation.  Drawdowns are used for energy production or to create additional space in the reservoir to hold back floodwaters; to reduce the cross-sectional area of the reservoir, increasing the current to aid downstream fish passage; and to expose normally submerged structures for maintenance. 

fish guidance efficiency (FGE):  The percentage of fish moving toward a dam’s turbine units that are diverted away by a fish guidance device, such as a submersible traveling screen.

fish ladder:  A series of ascending pools, similar to a staircase, that enables fish to migrate up the river past dams.  Also called a fishway.

fish passage efficiency:  The percentage of fish passing a dam but avoiding the turbine units.

fish sampling facility:  A facility at a dam where some portion of the fish moving past the dam are collected periodically for research purposes.

fish trapping or collection facility:  A facility where juvenile fish are captured to be transported down the river (around the dams) or adult fish are culled to be taken to a hatchery.

forebay:  The part of a dam’s reservoir that is immediately upstream of the powerhouse.

gatewell:  The slot on the upstream face of a concrete dam where hydraulic gates are stored when not used to close the turbine intakes.  (The gatewell also typically houses the fish screening device.)

generating capacity:  The maximum power that a power plant, such as a hydroelectric dam, can produce under specific conditions.

hydraulic capacity:  The maximum amount of water that can go through the powerhouse at a project.

intake:  The entrance to a turbine unit at a hydroelectric dam.

lock:  A chamber with watertight gates at each end used to lift or lower watercraft between the downstream tailrace water level and the upstream reservoir level.

mainstem:  The main channel of the river in a river basin, as opposed to the streams and smaller rivers that feed into it.  In the fish and wildlife program, mainstem refers to the Columbia and Snake rivers.

mid-Columbia:  The section of the Columbia River below Chief Joseph Dam and above the river’s junction with the Snake River.

Mid-Columbia Settlement Agreement: A process initiated by the Federal Energy Regulatory Commission, at the request of
state and federal fishery agencies and Indian tribes, dealing with protection of migrating salmonids.  FERC approved the first agreement among those parties and the
Mid-Columbia PUDs in 1980.

penstock:  The pipe leading from the water intake to the hydraulic turbine.

powerhouse:  That part of a hydroelectric dam where the turbine-generators are housed and where power is produced by the action of the water on the turbine blades.

pumped storage:  A hydroelectric project designed to store electrical energy on a short-term basis.  A pumped storage project is typically used to store electricity during nighttime periods of low demand for use during daily peak demand periods.

river miles:  Miles calculated from the mouth of the river or, for upstream tributaries, from the confluence with the main river.

run-of-the-river dams:  Hydroelectric dams without large reservoirs and, therefore, with only a limited capacity for water storage.  This means they also have limited control of their outflow and power generation.

sluiceway:  A channel designed to collect ice and trash in the river (e.g., logs) before they get into the turbine units and cause damage.

spill, spillbay:  Releasing water out the spillbays rather than through the turbine units. The spillbay is the dam’s safety valve.  Without it, excess water can damage the dam’s structure or overflow the dam.  Dams without bypass systems spill water laden with fish to carry them away from turbines.

storage dam:  A dam with a large reservoir that can hold water over from the annual high-water season to the following low-water season.  Of the major Columbia River Basin dams, the Grand Coulee, Brownlee, Dworshak, Hungry Horse, Libby, Round Butte, and Boundary dams are storage dams.

submersible traveling screen (STS):  A rotating screen, designed to fit into a dam’s turbine intake to divert fish up into bypass channels.

tailrace:  The canal or channel that carries water away from the dam.

tailwater:  The water surface immediately downstream from a dam.