The reservoir has declined more than 16 feet over the past year and is forecast to fall about 9 feet more by the end of this year. 'Due to how dry things have been, what we're seeing is Lake Powell's elevations are dropping,” says Mike Bernardo of the federal Bureau of Reclamation at Hoover Dam. And with the Southwest’s farmlands in peak irrigation season through June, Bernardo says, Lake Mead’s surface is dropping about 1 foot each week. The warm, dry conditions over the past two years have baked the watershed’s soils to such an extent, Bernardo says, that “when the snowmelt starts to run off, it just gets sucked up into the ground like a sponge.”īut the demands for water downstream from Hoover Dam continue. Inflows into Lake Powell from April through July are estimated to be just 26% of the long-term average, and that’s leading to rapid declines in both Powell and Mead, the two largest pieces of the river's water-storage system. The past 12 months have been among the driest on record across the Colorado River Basin. “Unfortunately, due to how dry things have been,” Bernardo says, “what we're seeing is Lake Powell's elevations are dropping.”Īnd that will mean less water flowing into Lake Mead for the rest of the year. Predicted water-level declines have grown as estimates of inflows into Lake Powell, the upstream reservoir, have shrunk due to extremely parched conditions across the upper watershed in the Rocky Mountains, where much of the river’s flow originates as melting snow.

Lately, each month’s report has brought worsening numbers. and Mexico that produce crops such as hay, cotton, grapes and lettuce.īernardo’s team also sets power generation goals and produces a monthly report with the latest projections of how reservoir levels will likely change over the next 24 months. As the reservoir falls toward record lows, its decline threatens the water supplies of cities and farmlands, and reveals how the system of managing water in the desert Southwest faces growing risks.īernardo leads a team of engineers and hydrologists who plan water releases from Hoover Dam, as well as Davis and Parker dams downstream, sending flows that travel through pipelines and canals to Phoenix, Los Angeles and farmlands in the U.S. One of the driest 22-year periods in centuries is colliding with the river's chronic overuse. Lake Mead is now just 37% full, headed for a first-ever official shortage and sinking toward its lowest levels since it was filled. Since 2000, the water level in the reservoir, which is the largest in the country, has dropped about 140 feet. The effects of years of severe drought and temperatures pushed higher by climate change are strikingly visible along Lake Mead’s retreating shorelines near Las Vegas, where the growing “bathtub ring” of whitish minerals coats the rocky desert slopes. But the rules for managing the river and dividing up its water - which were laid down nearly a century ago starting with the 1922 Colorado River Compact and which have repeatedly been tweaked - are now facing the greatest strains since the dam was built. With the concrete figures are words that encapsulate why the dam was built, as laid out in a 1928 law: FLOOD CONTROL, NAVIGATION, IRRIGATION, WATER STORAGE and POWER.Įighty-six years after its completion in 1935, the infrastructure at Hoover Dam continues doing what it was designed to do: holding water and sending it coursing through intake tunnels, spinning turbines and generating electricity.

In five relief sculptures by Oskar Hansen, muscular men are shown gripping a boat’s wheel, harvesting an armful of wheat, standing beside cascading water and lifting a heavy weight overhead. On top of the dam, where visitors peer down the graceful white arc of its face, one of its art deco-style towers is adorned with a work of art that memorializes the purposes of the dam. BOULDER CITY, Nevada - Hoover Dam towers more than 700 feet above Black Canyon on the Arizona-Nevada state line, holding back the waters of the Colorado River.

When the river runs dry pdf