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Lakes Mead and Powell, the largest reservoirs on the Colorado River, do not just store water. Their dams, Hoover and Glen Canyon, also generate electricity.

This hydropower drives irrigation pumps and fuels industries. It keeps the lights on for customers on tribal lands, in the basin’s largest cities, and in sleepy desert towns.

But less of it is being generated these days. Hydropower output at Hoover and Glen Canyon has dropped considerably since 2000. That’s because the reservoirs have declined due to a warming climate and over-extraction.

The graphics below show these energy and water trends. The line chart displays annual hydropower generation. The background image depicts water-level changes in the reservoirs over the same time period.

Graphic © Geoff McGhee/The Water Desk
Graphic © Geoff McGhee/The Water Desk

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