Bonneville Dam - History

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.

Prior to the New Deal, development of the Columbia River with flood control, hydroelectricity, navigation and irrigation was deemed as important. In 1929, the US Army Corps of Engineers published the 308 Report that recommended 10 dams on the river but no action was taken until the Franklin D. Roosevelt administration and the New Deal. Now at this 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. During the New Deal and funded from the Public Works Administration, in 1934, two of the larger projects were started, the Grand Coulee Dam and the Bonneville Dam. 3,000 workers in non-stop eight-hour shifts, from the relief or welfare rolls were paid 50-cents an hour for the work on the dam as well as raising local roads for the reservoir.

To create the Bonneville Dam and Lock, The Army Corps of Engineers first built one of the largest scale models in history of the purposed dam, the section of river it was to be located on, and its various components to aid in the study of the construction. First a new lock and a powerhouse was constructed which were on the south (Oregon) side of Bradford Island, and a spillway on the north (Washington) side. Coffer dams had to be built in order to block half of the river and clear a construction site where the foundation could be reached. These projects, part of the Bonneville Dam were completed 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. Although the dam began to produce hydroelectricity in 1937, Commercial electricity began its transfer from the dam in 1938.

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.