Bonneville Dam

100 Bonneville Lock and Dam consists of a number of dam structures that together whole a span of the Columbia River between the US states of Oregon and Washington at River Mile 146.1. The dam is situated 40 miles east of Portland, Oregon, in what is now the Columbia River Gorge National Scenic Area. The main 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 spread by the Bonneville Power Administration. Bonneville Lock and Dam are named for Army Capt. Benjamin Bonneville, an early explorer endorsed with charting much of the Oregon Trail. The name is marked BAH-nee-vill.

History
The unusual structures: a lock and powerhouse constructed on the south side of Bradford Island and a spillway on the north side were built by the 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, situated several miles upstream of Bonneville. Both the cascades and the old lock structure were submerged by Lake Bonneville, the tank that formed behind the dam. The original navigation lock at Bonneville was opened in 1938 and was, at that time, the biggest single-lift lock in the world.

Dimensions and statistics

Aerial view of spillway flanked by powerhouses, Bonneville Lock and Lake Bonneville beyond First Powerhouse – Constructed in 1933-37; 313 m long; 10 generators with an output capacity of 526,700 kW.
Spillway – Constructed 1933-37; 18 gates over a length of 442 m; maintains the reservoir usually 18 m above the river on the downstream side;
Second Powerhouse – Constructed 1974-81; 300.5 m long; 8 generators with a total generating capacity of 558,200 kW.
Bonneville Lock – Constructed in 1993 at a cost of $341 million; 26 m wide, 206 m long; transit time is approx. 30 minutes.
Lake Bonneville – 77 km long reservoir on the Columbia River created by Bonneville Dam; part of the Columbia-Snake Inland Waterway.