The United States is home to some of the most impressive dams in the world, serving crucial purposes such as flood control, irrigation, and power generation. In this article, we’ll explore the ten longest dams in the USA, showcasing these engineering marvels that span vast distances across the American landscape.
1. Herbert Hoover Dike (739,200 feet)
Topping our list is the Herbert Hoover Dike, an astounding 739,200 feet (about 140 miles) long structure encircling Lake Okeechobee in Florida. Built in 1965 for flood risk reduction, this earthen dam also serves multiple purposes including irrigation, navigation, and water supply. Despite its relatively modest height of 35 feet, its sheer length makes it a true giant among dams. It is nearly 10 times longer than the second longest dam in the USA!
2. Arthur V. Watkins Dam (76,665 feet)
Located in Utah, the Arthur V. Watkins Dam stretches an impressive 76,665 feet (about 14.5 miles). Completed in 1964, this earth-filled dam was built primarily for irrigation purposes. It creates the Willard Bay Reservoir, providing water for agriculture in the region.
3. Barker Dam (71,900 feet)
Texas is home to our third-longest dam, the Barker Dam, measuring 71,900 feet (about 13.6 miles). Built in 1945 by the U.S. Army Corps of Engineers, this dam plays a crucial role in flood risk reduction for the Houston area. It also offers recreational opportunities for local residents.
4. Addicks Dam (61,166 feet)
Another Texas giant, the Addicks Dam, spans 61,166 feet (about 11.6 miles). Constructed in 1948, it shares similar purposes with its neighbor, the Barker Dam, focusing on flood control and recreation. Both dams have been crucial in managing water flow in the Houston metropolitan area.
5. Cooper Dev – West Dike (51,216 feet)
South Carolina’s Cooper Dev – West Dike, also known as the Pinopolis West Dike, measures 51,216 feet (about 9.7 miles). Part of a larger hydroelectric and navigation project, this earth-filled dam was completed in 1942 and serves multiple purposes including flood control and water supply.
6. Cooper Dev – Pinopolis Dam (50,072 feet)
Companion to the West Dike, the Cooper Dev – Pinopolis Dam stretches 50,072 feet (about 9.5 miles). This multi-purpose dam, also completed in 1942, stands taller at 75 feet and incorporates both earth and concrete in its construction. It’s currently undergoing remediation to ensure its continued safe operation.
7. C-44 Reservoir (49,000 feet)
Florida’s C-44 Reservoir dam, completed in 2021, is one of the newest on our list at 49,000 feet long (about 9.3 miles). This project, involving both federal and state agencies, aims to improve water management in the region.
8. Yelm Canal Dike (48,050 feet)
Washington State’s Yelm Canal Dike, stretching 48,050 feet (about 9.1 miles), was built in 1930 primarily for hydroelectric purposes. Despite its age, this earth-filled dam continues to play an important role in local power generation.
9. North Tailings Dam (45,000 feet)
Utah’s North Tailings Dam, at 45,000 feet long (about 8.5 miles), is a unique entry on our list. Built for tailings management at a mining operation, this dam showcases how industrial needs have shaped America’s landscape.
10. Garrison Dam – Williston Levee (44,500 feet)
Rounding out our top ten is North Dakota’s Garrison Dam – Williston Levee at 44,500 feet (about 8.4 miles). Part of the larger Garrison Dam project completed in 1953, this structure plays a vital role in flood control along the Missouri River.
These ten dams, spanning thousands of feet across diverse landscapes, stand as testaments to American engineering prowess. From flood control to power generation, they continue to serve critical roles in water management, agriculture, and energy production across the United States.