Hoover Dam is so big that we can’t help but think its only purpose is to hold back the water behind its immense arc. But the dam has had many reasons for existence that keep shifting over time. And now the opening of the Boulder City Bypass this fall will put the longest single-span concrete arch in the country only 1,500 feet downstream from the dam—a new arc counterpoised with the old.
Hoover Dam, whose last bucket of cement was poured 75 years ago this May (and it’s still curing deep inside the structure), was conceived of as a public works project that would prevent the Colorado River from flooding agriculture in California, create work relief during the Great Depression and provide electricity. After World War II, the reservoir became popular as the Lake Mead National Recreational Area, and it was soon the single largest source of water for Las Vegas. That history, from Depression to prosperity, is signaled by the building of marinas along the shores of Lake Mead and the spread of lights along the Strip.
What the dam stood for has also changed over time. In 1955 the American Society of Civil Engineers named Hoover Dam one of the Seven Modern Engineering Wonders of the World, and in 1985 it was designated a National Historic Landmark. In between, environmentalists came to see it as a threat to the health of the river and advocated for its demolition.
The status of Hoover Dam as a tourism destination started out modestly; in the early days you could only approach it from the Arizona side along a dirt road. Now it sees an average of 14,000 vehicle crossings a day. The most recent wrinkle is that the route across the river has become important to the North American Free Trade Agreement, a corridor for goods flowing through the West from Mexico to Canada. And that’s a problem, as the dam can’t accommodate the increased traffic, nor will the Homeland Security Department allow trucks across it since 9/11. Hence the Mike O’Callaghan-Pat Tillman Memorial Bridge (named after the former Nevada governor and the Arizona football player/U.S. Army Ranger killed in Afghanistan.)
Like the dam, the bridge features a jaw-dropping amount of curved engineering, atop of which will run a road—the newest version of that old dirt route from Arizona. The soaring arch meets the straight road at its apex, with the pavement seeming to appear out of nowhere from the deeply cut approaches on both sides of the canyon. The pavement flies almost 900 feet above the river, touches the arc, then continues to other side. If the designers of Cirque de Soleil created infrastructure instead of showroom sets, this kind of daring would be in their vocabulary.
At night, Hoover Dam is bathed with light, and so will be the bridge. Safety for drivers is part of the reason, security for the structures another. But it’s also for aesthetics, for the sheer audacious theater of bridging the aptly named Black Canyon with imagination. Plenty of reasons exist in the world to decry the hubris of monumental engineering projects interfering with the flow of nature. But sometimes you just have to acknowledge that such structures are also monuments to human drive and ingenuity, which are also part of nature.
Although foot traffic will still be allowed across the dam upon the opening of the bypass, all vehicular traffic will use the new bridge, and you will be able to approach the dam only from the Nevada side. Hoover Dam will appear to us in yet a different light—seen from above. The bridge will be so high that you won’t see the dam from most car windows, and it’s difficult to say which will be more popular, the walk across the dam or the walk across the bridge to see the dam. I’m going to predict that people will want to do both, and that dusk will be the time they choose, just as daylight fades and the lights come up.