Bonneville Dam

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Bonneville Dam
Bonneville Lock and Dam
Spillway structure
Locale Columbia River Gorge National Scenic Area
Maintained by US Army Corps of Engineers (Operator)
Bonneville Power Administration (Marketer)
Construction began 1933 (First Powerhouse)
1974 (Second Powerhouse)
Opening date 1937 (First Powerhouse)
1981 (Second Powerhouse)
Geographical Data

Bonneville Lock and Dam consists of several dam structures that together complete a span of the Columbia River between the US states of Oregon and Washington at River Mile 146.1. The dam is located 40 miles east of Portland, Oregon, in what is now the Columbia River Gorge National Scenic Area. The primary functions of Bonneville Lock and Dam are those of electrical power generation and river navigation. The dam was built and is managed by the US Army Corps of Engineers. Electrical power generated at Bonneville is distributed by the Bonneville Power Administration. Bonneville Lock and Dam is named for Army Capt. Benjamin Bonneville, an early explorer credited with charting much of the Oregon Trail. The name is pronounced BAH-nee-vill or BAH-nuh-vill.

Contents

[edit] History

The original structures: a lock and powerhouse constructed on the south (Oregon) side of Bradford Island and a spillway on the north (Washington) side, were built by the U.S. Army Corps of Engineers during the New Deal—started in 1933 and finished in 1937. Prior to this damming of the river, a set of locks that were opened in 1896 moved ships around Cascades Rapids, located several miles upstream of Bonneville (see Cascade Locks, Oregon). Both the cascades and the old lock structure were submerged by the Bonneville Reservoir, the reservoir that formed behind the dam. The original navigation lock at Bonneville was opened in 1938 and was, at that time, the largest single-lift lock in the world.

In his song Roll on, Columbia, the folk singer, Woody Guthrie, spoke of Bonneville as follows:

At Bonneville now there are ships in the locks,
The waters have risen and cleared all the rocks,
Shiploads of plenty will steam past the docks,
So roll on, Columbia, roll on.

At the time, America was in the Great Depression, and the dam's construction provided important jobs and money for the Pacific Northwest, providing hydropower (hydroelectricity) that gave cheap energy to aluminum plants in the area, and enabling transportation 188 miles up the Columbia.

A second powerhouse (and dam structure) was started in 1974 and completed in 1981. The second powerhouse was built by widening the river channel on the Washington side, creating Cascades Island between the new powerhouse and the original spillway. The combined electrical output of the two power houses at Bonneville is now over 1 million kilowatts.

Despite its world record size in 1938, Bonneville Lock became the smallest of seven locks built subsequently at different locations upstream on the Columbia and Snake Rivers; eventually a new lock was needed at Bonneville. This new structure was built on the Oregon shore, opening to ship and barge traffic in 1993. The old lock is still present, but is no longer used.

The dam features fish ladders to help native salmon and steelhead get past the dam on their journey upstream to spawn. The large concentrations of fish swimming upstream serves as a tourist attraction during the spawning season. California Sea Lions are also attracted to the large number of fish, and are often seen around the base of the dam during the spawning season. By 2006, the growing number of crafty sea lions and their impact on the salmon population have become worrisome to the U.S. Army Corps of Engineers and environmentalists[1] [2].

The dam blocked the migration of white sturgeon to their upstream spawning areas. Sturgeon still spawn in the area below the dam and the lower Columbia River supports a healthy sturgeon population. Small very depressed populations of white sturgeon persist in the various reservoirs upstream.

[edit] Dimensions and statistics

  • First Powerhouse – Constructed in 1933-37; 313 m (1,027 ft) long; 10 generators with an output capacity of 526,700 kW.
  • Spillway – Constructed 1933-37; 18 gates over a length of 442 m ( 1450 ft); maintains the reservoir (upriver) usually 18 m (60 ft) above the river on the downsteam side;
  • Second Powerhouse – Constructed 1974-81; 300.5 m (986 ft) long; 8 generators (plus two at fish ladders) with a total generating capacity of 558,200 kW.
  • Bonneville Lock – Constructed in 1993 at a cost of $341 million; 26 m (86 ft) wide, 206 m (675 ft) long; transit time is approx. 30 minutes.
  • Lake Bonneville – 77 km (48 mi) long reservoir on the Columbia River created by Bonneville Dam; part of the Columbia-Snake Inland Waterway.

[edit] Taking the tour

The fish hatchery and dam are open year round from 9:00am to 5:00pm. It is best to visit the dam in the months of April through September when the salmon are more abundant.

There are fish viewing windows and visitors' centers on both the Oregon and Washington sides of the dam. Because of security concerns, visitors may be required to show ID, and it is not possible to cross the entire dam. During most of the year, more fish use the Washington shore fish ladders, so fish viewing may be better on the Washington side of the dam. *Fish Counts

[edit] Gallery

Generators inside the second powerhouse

Fish ladder at Bonneville Dam

Aerial view of spillway flanked by powerhouses, Bonneville Lock (near right) and Lake Bonneville beyond

Cross-section of the spillway with tainter gates and flip lip

[edit] References

  • Bonneville Lock and Dam. A National Historic Landmark Serving the Northwest. 2001. U.S. Government Printing Office, 2001-691-677. U.S. Army Corps of Engineers, Portland District, public information pamphlet distributed at the Bonneville Lock and Dam visitor centers.

[edit] External links

Columbia River Dams
Bonneville • The Dalles • John Day • McNary • Priest Rapids • Wanapum • Rock Island • Rocky Reach • Wells • Chief Joseph • Grand Coulee • Keenleyside • Revelstoke • Mica


Crossings of the Columbia River
Upstream
Bridge of the Gods
 Bonneville Dam
 Downstream
Glenn L. Jackson Memorial Bridge
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