Bonneville Dam

Bonneville Lock and Dam consists of several dam structures that together complete a span of the Columbia River between the U.S. states of Oregon and Washington at River Mile 146.1. The dam is located east of Portland, Oregon, in the Columbia River Gorge. The primary functions of Bonneville Lock and Dam are electrical power generation and river navigation. The dam was built and is managed by the United States 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 Bonneville Dam Historic District was designated a National Historic Landmark District in 1987.

History

In 1896, prior to this damming of the river, the Cascade Locks and Canal were constructed, allowing ships to pass the Cascades Rapids, located several miles upstream of Bonneville.

During the New Deal, the Army Corps of Engineers constructed a new lock and a powerhouse which were on the south (Oregon) side of Bradford Island, and a spillway on the north (Washington) side. These were started in 1933 and finished in 1937.

Both the cascades and the old lock structure were submerged by the Bonneville Reservoir, also known as Lake Bonneville, 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 jobs and other economic benefits to the Pacific Northwest. Inexpensive hydroelectricity gave rise, in particular, to a strong aluminum industry.

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 Army Corps of Engineers and environmentalists. Historically, pinnipeds such as sea lions and seals hunted salmon in the Columbia River as far as The Dalles and Celilo Falls, from the sea, as remarked upon by people such as George Simpson in 1841.

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.

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 downstream side;
• Second Powerhouse – Constructed 1974-82; 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 1987 to 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.

It was declared a National Historic Landmark in 1987.

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

Gallery

See also

• Cascade Locks and Canal, which preceded the construction of the dam
• Grand Coulee Dam, a much larger dam far upstream on the Columbia River
• Charles McNary, a U.S. Senator from Oregon who was instrumental in passing legislation to build the dam

References

External links

• U.S. Army Corps of Engineers - Bonneville Lock and Dam
• Bonneville Power Administration
• Dams of the Columbia Basin & Their Effects on the Native Fishery
• Bonneville Project: 42 photos and 76 data pages, at Historic American Building Survey