Most Americans had never heard of the Oroville Dam — the tallest dam in the U.S. — before the current crisis that has spurred the evacuation of tens of thousands of people. Yet there are dozens of huge American dams, most in the western states, that are virtually unknown to people outside their region. We take these structures for granted, even though millions depend on them for cheap energy, irrigation, flood control and drinking water. Here are 10 of the most notable dams in the U.S., based on size, history and other intangibles.
10. Dworshak Dam (Idaho)
This dam in northwest Idaho is the third tallest in the U.S. at 717 feet — just behind Hoover at 726 feet — and the tallest straight-axis concrete dam in the Western Hemisphere. Completed in 1973, the construction cost of $327 million would translate to $1.8 billion today.
9. Fontana Dam (North Carolina)
As noted earlier, almost all of the largest hydroelectric dams are located in the Western U.S. The Fontana Dam in Western North Carolina is the tallest dam (480 feet) in the Eastern U.S., but it ranks only 20th nationwide. Completed in 1944, it’s best known for sparking a legal battle between the U.S. government and local residents that’s still in court almost 75 years later. At the time of construction, federal officials promised to build a road on the north shore of Fontana Lake to replace a road flooded by the reservoir. The government built only a 7-mile stretch, the infamous “Road to Nowhere,” before halting construction in the 1970s. Swain County, N.C., sued in 2016 to recover $39 million it says the federal government still owes it as part of the agreement.
8. Oahe Dam (South Dakota)
Located on the Missouri River just north of Pierre, S.D., this dam doesn’t awe visitors with a huge concrete face like Hoover and some other dams in this story. But the earthfill dam, completed in 1962, impounds Lake Oahe, the fourth-largest artificial reservoir in the U.S.
7. New Melones Dam (California)
Approved in 1944, construction on this 625-foot-tall embankment dam didn’t begin until 1966. By then, the growing environmental movement stepped forward and challenged construction, claiming the wild and scenic Stanislaus River canyon was more valuable than a hydroelectric project. Even after completion of the dam in 1979, one opponent gained national fame by chaining himself to a rock in the canyon, hoping to prevent the reservoir from being filled.
Many regard the construction of the dam as a turning point in the history of giant hydropower dams. As the 2003 book, Dam Politics: Restoring America’s Rivers, by William R. Lowry, notes, “The New Melones Dam was one of the last of its kind. … no structure as large or as significant has since been built on an American river. And since this date, virtually no structural modification to a river in this country has gone unopposed.”
6. Buffalo Bill Dam (Wyoming)
The 350-foot-tall concrete-arch gravity dam became the tallest dam in the world when it was completed in 1910 along the Shoshone River. Originally dubbed the Shoshone Dam, it was later named in honor of the iconic Western showman William “Buffalo Bill” Cody, who played a key role in getting the dam built. It is listed as a National Civil Engineering Landmark.
5. Oroville Dam (California)
Oroville Dam used its emergency spillway in early February to reduce the level of storm-swelled Lake Oroville. Opened for the first time in the dam’s almost 50-year history, the spillway failed, and evacuations were ordered for almost 200,000 people living downstream. Officials believe it could take up to $200 million to repair the dam’s spillway.
That’s a hefty figure, but a proverbial drop in the bucket compared to the amount needed to upgrade dams nationwide. In their last report in 2013, the American Society of Civil Engineers gave the nation’s dams an overall grade of “D.” The ASCE estimated $54 billion would need to be spent through 2018 upgrading dams. The problem is expected to get worse before it gets better; there are more than 85,000 dams in the U.S., with an average age of about 55 years old.
4. Fort Peck Dam (Montana)
It stands only 250 feet tall, but Fort Peck is massive, spanning more than four miles (21,026 feet) in width. The reservoir behind it on the Missouri River, Fort Peck Lake, is the fifth-largest man-made lake in the U.S. Completed in 1940 as part of the New Deal, a failure during construction led to eight deaths; six of those bodies were never recovered and are buried in the embankment dam. That event undoubtedly inspired the urban legend that there are bodies entombed in the Hoover Dam.
3. Glen Canyon Dam (Arizona)
Finished in 1966 at a cost of $135 million (more than $1 billion in 2017 dollars), the dam impounds Lake Powell, one of the most popular recreation spots in the Southwestern U.S. The dam’s construction flooded the spectacular but largely unexplored Glen Canyon; that inspired environmentalists in the late 1960s to fervently lobby against the construction of two huge dams in the Grand Canyon. The U.S. scrapped plans to build those dams.
Given the nature of the Oroville Dam crisis, there’s a similar incident in the Glen Canyon Dam’s past. According to the Los Angeles Times, high water in Lake Powell in 1983, coupled with major erosion in the spillway tunnels, led officials to fear “for the safety of the dam and its foundation.” According to the Times, “What would then happen was anyone’s guess. A wall of water could have roared through the Grand Canyon and overwhelmed everything in its path, starting with Hoover Dam. The subsequent huge loss of life, property, power and water would have been disastrous.”
2. Grand Coulee Dam (Washington)
Completed in 1942 along the Columbia River, the 550-foot-tall Grand Coulee boasts the largest capacity of any power plant in the U.S. It’s one of the reasons the state of Washington generates more hydroelectric power than any other state. Hydropower provided about 6 percent of the total energy production in the U.S. in 2015.
1. Hoover Dam (Arizona and Nevada)
Still the second tallest dam in the U.S. at 726 feet, the Hoover Dam was three times larger than any dam that had ever been built when it opened in 1936. The dam remains in fine shape more than 75 years later, but its reservoir, Lake Mead, is not. An historic drought lasting much of the past two decades has led to decreasing water levels; the reservoir reached a record low in 2016, and residents in California, Arizona and Nevada face severe water shortages if the drought continues.