US 93 passes over the Colorado via the top of Hoover Dam, which provides the only crossing point for hundreds of miles. The roads on both sides of the river are very steep, narrow and winding and the approach from either direction is equally dramatic.
Black Canyon: The Black Mountains to the east and the Eldorado range to the west are twisted and devoid of vegetation but also quite colorful, and they provide an impressive backdrop to the dam. At the time of construction, Hoover Dam was the largest in the world and it is still an amazing structure and a marvel of engineering - a
huge wall of concrete 660 feet thick at the base and 726 feet high set between the walls of Black Canyon with its associated strangely-angled pylons,
wires and machinery. In 1955, the dam was selected as one of the Seven Modern
Engineering Wonders in the USA by the American Society of Civil Engineers.
Tours of Hoover Dam: New visitor facilities were constructed in the late 1990s although parking is still limited, especially for large vehicles which have to use overflow areas on the Arizona side. Forty minute guided tours are available down into the dam and around the generating rooms inside. They used to begin via elevators on the top of the dam itself and generally required only a short wait, but now the entrance is through the new visitor center; when I was last there several hundred people were queuing - estimated waiting time 2 hours. This did not seem a very appealing prospect since the temperature outside was 110 °F and the air-conditioning was not very efficient.
The Spillway Channel: If the wait for the tour is too long, it is still well worth walking across the dam to see the various parts of the structure, including the huge spillway channel (50 foot diameter) on the Arizona side intended to take excess water if flood conditions exist. This has only been used twice since the dam was built, most recently in 1983 when record flows along the Colorado caused potentially dangerous water levels to build up.
Hoover Dam Bypass: US 93 is a wide dual carriageway for most of its length, as befitting the main route between Arizona and Nevada, but for a short distance either side of Hoover Dam it becomes a steep, narrow, two lane road with a 15 mph speed limit. This, plus the ever increasing traffic, and growth in visitors to the dam led to the decision, in 1998, to reroute the highway half a mile to the south, at Sugarloaf Mountain, crossing the Colorado via a 2000 foot road bridge. The design process began in 2001, and the new route is currently on schedule to open for traffic in the third quarter of 2008. The three main components of the project are 2 miles of new road in Arizona, 3 miles in Nevada, and the bridge itself.
Satellite Photo/Map: View above the Hoover Dam:
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