The rate of storage expansion has slowed since the mid-20th century
Hoover Dam was not the first dam built in the United States, but the concrete wall across Boulder Canyon, on the Colorado River, was symbolic of an era.
As the graphic below shows, reservoir storage capacity in the United States expanded dramatically in the half-century following Hoover Dam’s completion in 1936. The reservoir behind the dam, Lake Mead, still is the largest man-made body of water in the United States.
Other countries soon followed this path. Reservoir expansion began to soar in the rest of the world roughly 20 years later, in the 1950s.
Water storage, which helps buffer society against seasonal and annual fluctuations in precipitation, remains a critical and controversial question, especially as countries seek to adapt to climate change by adding new reservoirs. Most of the prime spots have already been dammed, but new reservoirs are still being proposed.
Reservoirs are not the only remedy. Other storage options are gaining traction: changing the management of existing dams to reflect the changing nature of storms; storing water underground where it will not evaporate; trapping rainwater in cisterns, ponds, and other small catchments; and increasing the water-holding capacity of the soil.
Per Capita Capacity
The second graphic shows, by country, reservoir storage capacity per person. Canada and Russia have a large amount of storage compared to their populations. Most countries in Africa and South Asia do not.
These graphics were made to accompany the article Water Storage a Critical Question for Climate Adaptation by Circle of Blue reporter Brett Walton. Contact Brett Walton or by @waltonwater on Twitter.
Brett writes about agriculture, energy, infrastructure, and the politics and economics of water in the United States. He also writes the Federal Water Tap, Circle of Blue’s weekly digest of U.S. government water news. He is the winner of two Society of Environmental Journalists reporting awards, one of the top honors in American environmental journalism: first place for explanatory reporting for a series on septic system pollution in the United States(2016) and third place for beat reporting in a small market (2014). He received the Sierra Club’s Distinguished Service Award in 2018. Brett lives in Seattle, where he hikes the mountains and bakes pies. Contact Brett Walton