Lake Mead, Nation’s Largest Reservoir, To Reach Record Low This Week

The last time Lake Mead, the largest reservoir in the United States, reached maximum capacity was 1983. This week the lake, located along the Colorado River near Las Vegas, Nevada, is expected to reach a new milestone — its lowest point ever.

Formed by the Hoover Dam, Lake Mead has been suffering for years as an expansive drought across the West, coupled with rising temperatures and populations, has overstressed the massive man-made body of water. According to forecasts from the federal Bureau of Reclamation, water levels will fall this week to their lowest since it was first filled in 1937. The lake, which provides water for 20 million people across the Southwest has been losing water for over a decade and is currently at about 40 percent capacity.

Christie Vanover with the Lake Mead National Recreation Area confirmed with ThinkProgress that the lake is projected to drop below the record low of 1081.82 feet this week, probably on Wednesday. She said the lake will be extending boat ramps to reach the lower levels.

The Bureau of Reclamation published a projection in June showing Lake Mead’s water level falling to 1,064 feet by May 2016.

Nearby Las Vegas gets 90 percent of its water from the lake. With one of the city’s two intake pipes at risk of being exposed, the city is hard at work drilling an expensive three-mile-long tunnel to access deeper reserves.

Bronson Mack with the Las Vegas Valley Water District told ThinkProgress that the third intake tunnel is about 70 percent complete and will be completed sometime next year.

“As lake levels continue to drop as we’ve seen over the past 14 years, the threat of the lake dropping below one of the existing intakes could have impacted about half our capacity,” he said.

Mack said the city has also focused on conservation efforts, including their most successful measure of encouraging residents to remove grass and replace it with water-efficient landscaping. He said this has resulted in the removal of 160 million square miles of grass from the valley.

The dropping water levels, at up to two feet per month, are not only impacting recreation and water supply for millions, including California’s already parched agricultural industry, but also putting hydropower in jeopardy. With less pressure as the water enters turbines that run the electricity generators, the current capacity is about 1,592 MW — down from the 2,074 MW that’s achievable. This could drop to about 1,120 MW by May 2016 if predictions hold.

A 2007 shortage-sharing agreement sets three elevations for which water restrictions will be imposed on the Lower Basin states of Arizona, California, Nevada, and New Mexico. The first shortage level, 1,075 feet, will likely come into effect in the next year or two. It would require a total water use cut of 4.4 percent, with Arizona taking an 11 percent cut, Nevada a four percent cut, New Mexico 3.3 percent and California remaining the same.

As climate change renders the Southwest hotter and drier and the population of cities across the region continues to swell, dated water laws dictate the future of one of the most vulnerable regions in the country. At stake are major portions of the nation’s agricultural sector, priceless environmental treasures, and the water supply of millions of people.

“Nineteenth century water law is meeting 20th century infrastructure and 21st century climate change,” Bradley Udall, a senior fellow at the University of Colorado Law School, told the Los Angeles Times, “and it leads to a nonsensical outcome.”

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