Wanapum Dam

Wanapum Dam
Williamborg 01:57, 28 April 2008 (UTC) · Public domain · source
Name	Wanapum Dam
Location	Grant County, Washington, United States
River	Columbia River
Operator	Public Utility District No. 2 of Grant County
Type	Gravity, run-of-the-river
Construction began	1959
Opening	1963
Plant capacity	1,093 MW
Plant turbines	10 Kaplan-type

Wanapum Dam

Wanapum Dam is a concrete gravity dam on the Columbia River in Grant County, Washington, United States, completed in 1963 and operated by Public Utility District No. 2 of Grant County. The project created a reservoir that reshaped river transport and regional development, linking to broader Pacific Northwest hydropower systems such as Grand Coulee Dam, Bonneville Dam, and The Dalles Dam. Its construction intersected with issues involving the Wanapum people, U.S. Army Corps of Engineers, and regional utilities including Bonneville Power Administration.

History

Construction began after licensing and planning processes involving state and federal entities including the Federal Power Act frameworks and coordination with the U.S. Bureau of Reclamation. The dam was built by contractors under the auspices of the local Public Utility Districts movement that traces ties to figures like Franklin D. Roosevelt era public-works policies and projects such as the Tennessee Valley Authority and Bonneville Project. Opening ceremonies in the 1960s took place amid contemporaneous infrastructure milestones like the completion of Interstate 90 segments and expansion of power grids managed by the Northwest Power and Conservation Council. Miners, engineers, and labor unions similar to the International Brotherhood of Electrical Workers and the American Federation of Labor and Congress of Industrial Organizations were active during construction. The dam’s name references the indigenous Wanapum people, and its history is tied to indigenous displacement and legal frameworks such as treaties like the Treaty of Point Elliott. Later events include seismic concerns raised after earthquakes such as the 1965 Rat Islands earthquake and regional studies following the 1980 eruption of Mount St. Helens.

Design and Specifications

The structure is a concrete gravity dam employing spillways, sluice gates, and a powerhouse containing Kaplan turbines akin to installations at John Day Dam and McNary Dam. Design work reflected engineering practices advanced in projects like Hoover Dam and drew on hydroelectric expertise seen in Seattle City Light developments. Specifications include a height comparable to some Columbia projects, a length spanning river channels used historically by Columbia Plateau navigation, and a powerhouse capacity integrated into the Northwest Power Grid. Components such as transformers and switchyards interface with regional transmission lines maintained by entities including Pacific Northwest Utilities Conference Committee. The project required access roads and construction staging related to nearby transportation infrastructure including the U.S. Route 2 and rail corridors of the Union Pacific Railroad.

Power Generation and Operations

The plant capacity of roughly 1,093 megawatts is delivered by multiple Kaplan turbines, with generation schedules coordinated with regional balancing authorities like Bonneville Power Administration and market participants including Avista Corporation and Puget Sound Energy. Operations integrate with Columbia River system management policies developed by the Northwest Power and Conservation Council and regulatory oversight from agencies such as the Federal Energy Regulatory Commission. Seasonal flow management aligns with irrigation districts such as the Columbia Basin Project and with flood control criteria used at Grand Coulee Dam. Ancillary services and grid reliability interactions involve entities like North American Electric Reliability Corporation. Maintenance cycles, outage coordination, and fish-passage mitigation are scheduled with input from U.S. Fish and Wildlife Service and state agencies such as the Washington State Department of Ecology.

Reservoir and Hydrology

The reservoir inundated portions of the Columbia River Gorge and altered hydrology for upstream reaches including tributaries like the Yakima River and the Wanapum Lake impoundment. Water level operations are coordinated with reservoir management at other Columbia projects including Wells Dam and Duncan Dam under interstate compacts involving the State of Washington and the Bonneville Power Administration. Flow records and sediment dynamics are studied by research institutions such as University of Washington and Pacific Northwest National Laboratory, and are relevant to fisheries managed under the Columbia River Basin recovery plans and restoration efforts guided by the Northwest Power Act.

Environmental and Cultural Impacts

The dam’s creation impacted anadromous fish runs such as Chinook salmon, Coho salmon, and Steelhead trout, prompting mitigation measures including fish ladders and hatcheries operated by agencies like the Nez Perce Tribe fisheries programs and the Washington Department of Fish and Wildlife. Cultural sites of the Wanapum people and other Plateau tribes were inundated, with repercussions addressed in consultations invoking statutes like the National Historic Preservation Act and involving institutions such as the Smithsonian Institution and regional museums. Environmental reviews have involved the Environmental Protection Agency and litigation in federal courts, with plaintiffs including tribal governments and conservation organizations like Sierra Club and National Audubon Society.

Safety, Inspections, and Rehabilitation

Inspections by engineers and oversight by the U.S. Army Corps of Engineers-aligned standards and FERC relicensing processes identified issues including concrete cracking and seismic vulnerability similar to concerns raised at other aging infrastructure like Folsom Dam. In the 2010s emergency responses drew on state emergency management agencies such as the Washington State Emergency Management Division and federal assistance frameworks under the Federal Emergency Management Agency. Rehabilitation programs involved contractors and consultants with precedents from projects at Hoover Dam and Glen Canyon Dam, and funding mechanisms included bonds overseen by Public Utility District commissions and financing guided by the Bonneville Power Administration marketplace.

Recreation and Local Economy

The reservoir supports boating, angling for species managed by Washington Department of Fish and Wildlife, and parks administered by entities like the Washington State Parks and Recreation Commission and local county authorities such as Grant County. Tourism links to regional attractions including Columbia River Gorge National Scenic Area, wineries of the Columbia Valley AVA, and communities like Vantage, Washington and Wenatchee, Washington. Economic impacts extend to irrigation for agriculture in the Columbia Basin, hydro-dependent industries, and recreation businesses that interface with organizations such as the Chamber of Commerce and regional economic development councils like Economic Development Council of Grant County.

Category:Dams in Washington (state) Category:Hydroelectric power stations in Washington (state)