Several years ago, I drove from Las Vegas to the Hoover Dam. The 30-odd mile trip, which takes some forty-five minutes, snakes down Nevada Route 93, the Great Basin Highway, in a southeasterly direction, past the town of Henderson. Departing Las Vegas, which sits at an elevation of approximately 2,000 feet (610 m), one drives along the spine of the edge of the Basin and Range province, towards a 400 foot (122 m) elevation at the Hoover Dam. Remember, the dam is at river level.
Once, I parked the car in the Boulder Dam Bridge Parking lot, I walked across, what today is, the Mike O’Callaghan-Pat Tillman Memorial Bridge Plaza, (Figure 1.), and saw the four towers that rise out of the water like apparitions. (Figure 2). These towers measure, 338 feet (103 meters) high, and are the dam’s water intake towers. They stand, upright , like soldiers in formation, in the waters of Lake Mead, the dam’s reservoir, which is situated behind the Hoover Dam. (Figure 2.)
I stood on the dam’s rim, with the other tourists that gathered that day, andthen, peered down, this concrete marvel’s 726 feet (221 meters) height, 67 stories down into the abyss ofthe diverted Colorado River. (See Figure1). According to our tour guide, the damhas two pipes, that are like tunnels, each of which, can easily envelop a twolane highway. Hoover Dam’s hydroelectricsystem, we were also told, powers 17 generators thatare capable of producing up to 4 billion (one hundred million) kilowatts of electricityper annum, making it one of the United States’ principal hydroelectric power resources. Indeed, the electricity the damproduces, not only powers Las Vegas and Phoenix, but also Los Angeles. The dam’s operations are self-supporting, via revenues generated by the saleof its electricity.
Figure 1: Hoover Dam’s Mike O’Callaghan-Pat Tillman Memorial Bridge
Figure 2: Hoover Dam’s Water Intake Towers
 “Hoover Dam generates, on average, about 4 billion kilowatt-hours of hydroelectric power each year for use in Nevada, Arizona, and California – enough to serve 1.3 million people. From 1939 to 1949, Hoover Powerplant was the world’s largest hydroelectric installation; today, it is still one of the country’s largest . . . There 17 main turbines in the Hoover Powerplant — nine on the Arizona wing and eight on the Nevada wing. The original turbines were replaced through an uprating program between 1986 and 1993.” United States, Department of the Interior, Bureau of Reclamation, Hoover Dam, Frequently Asked Questions and Answers, Hydropower at Hoover Dam (Last updated Aug. 1, 2018), https://www.usbr.gov/lc/hooverdam/faqs/powerfaq.html
 United States Geological Survey (USGS), Mike O’Callaghan-Pat Tillman Memorial Bridge, (Credit: Alex Demas, USGS. Public domain), (Dec. 22, 2014) https://www.usgs.gov/ media/images/mike-ocallaghan-pat-tillman-memorial-bridge.
 United States Geological Survey (USGS), Hoover Dam Intake Towers, (Credit: Alex Demas, USGS. Public domain), (Dec. 22, 2014), https://www.usgs.gov/media/images/hoover-dam-intake-towers.