Wednesday, 11 June 2008

The Hoover Dam

The Hoover Dam is one of the World's iconic man-made features. It was built during the Great Depression, came into service in 1936 and is still performing well today.

Unusually for a major project, it was brought in on time, on specification and on-budget, like the Empire State building completed a little earlier. Again, like the Empire State building, it was the product of a vision that, in the late nineteenth and twentieth centuries, I particularly associate with the United States as Great Britain progressively lost its former confidence in carrying out these bold initiatives. Because of the poor economic conditions in the U.S.A. at the time, labour was readily available to complete the work but the privations and dangers suffered by the workforce are now hard to believe, in these days of enhanced 'Health and Safety'.

I'd always wanted to visit the structure and my visit to Las Vagas in 2008 provided the opportunity. My helicopter ride to the Grand Canyon gave me stunning views of the dam from the air and one of my pictures is shown above. In this picture, Nevada forms the left bank and Arizona the right bank. Lake Mead is at the top of the picture and the Colorado River at the bottom. On the left, Route 93 from Las Vegas descends via a series of hairpins so as to cross the top of the dam en route for Phoenix, Arizona. The visitor centre is on the Nevada side adjacent to the dam. The long, flat-roofed buildings extending away from the dam are the two Turbine Halls where electricity is generated. The structure under construction in the foreground is the new road bridge which, when completed, will divert road traffic away from the top of the dam.

The day after my helicopter ride, I visited the dam by road, descending by lift to the Nevada Turbine Hall and then taking a raft on the Colorado River to approach the dam at water level. Details of my visit to Hoover Dam.

Although the Hoover Dam incorporates a major hydro-electric generating station, the principal reason for construction was flood control. When the winter snows melt in the Rockies, incredible amounts of water come down the Colorado River and, before the building of the Dam, widespread damage was caused annually through inundation. Since the inauguration of the Dam in 1932, these waters can be stored in the artificial lake created behind the dam, Lake Mead, and progressively released in a controlled fashion, simultaneously generating power. At the time, Lake Mead was the largest artificial lake in the world (taking the title from Lake Gatun, on the Panama Canal, which I was to visit later on the same trip).

The agricultural areas of Southern California are the largest water consumer served by the Hoover Dam but the remarkable growth of Las Vegas has been made possible by the secure water supply. Initially, the hydro-electric generating plant at Hoover Dam was key to the electrification of Las Vegas and the surrounding areas but the generating capacity, although still important, is no longer a 'base-load' plant but is used as required, exploiting the flexibility of hydro-electric plant to start and stop at short notice.

Sales of water and electricity since 1936 mean that the capital cost of the scheme has been fully recovered - current income now services the maintenance of the installations.

In 1936, the Department of the Interior, Bureau of Reclamation published a book describing the construction of the dam. Now in its 32nd printing, it's still available (ISBN 0-916122-51-4) and gives a fascinating insight into this achievement.

Incidentally, at the time of construction, the name 'Boulder Dam' was used. Congress changed the name to 'Hoover Dam' in 1947.

More information is given in the excellent Wikipedia article.

My pictures of Hoover Dam.