Infographic: Filling America's Great Reservoirs
Follow the timeline as the largest U.S. dams and reservoirs are constructed.
The ongoing drought in the Western United States has alarmed residents who have relied on the region’s vast reservoirs to provide water for industry, agriculture, and drinking. The drying up of Lake Mead and Lake Powell in particular has reversed a grand engineering project in the middle part of the 20th century to construct giant reservoirs. There are 129 reservoirs in the U.S. with more than 1 million acre-feet of capacity, and they cumulatively can hold nearly 400 million acre-feet of water.