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Climate and Environment

What The Startling Low Water Levels In Lake Mead Mean For LA

Boats sit in the waters as a large swath of a nearby cliff shows the previous water level significantly higher.
A woman paddles across the water at Lake Mead, Nevada on July 23. Water levels in Lake Mead are at the lowest level since April 1937 when the reservoir was being filled for the first time, according to NASA.
(Frederic J. Brown
AFP via Getty Images)
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NASA recently released startling satellite images of Lake Mead, which the agency notes is now at its lowest since April 1937, when the reservoir was still being filled for the first time.

A measurement taken on July 18 put Lake Mead at just 27% of capacity. That effect you see in the image above — with the lighter color on the cliffs where the water level once was — is known as the "bathtub ring."

NASA called the images released "a stark illustration of climate change and a long-term drought that may be the worst in the U.S. West in 12 centuries."

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Water levels on the Overton Arm of Lake Mead from left to right in 2000, 2021 and 2021 show startlingly less of water over time
(Courtesy NASA)

Which made us wonder: What does the reservoir's low level means for L.A.'s water supply?

Lake Mead, which gets its water from the Colorado River, is a very important source of water for Southern California.

Map of California showing sources of L.A.'s water
Los Angeles water sources map shows where L.A. gets its water.
(LADWP 2020-21 Briefing Book)

So we talked to Nicola Ulibarri, who teaches urban planning at UC Irvine to understand the impact.

"It'll vary a little bit depending if you're in Los Angeles versus Orange County versus San Diego. But on average, we get about a quarter of our water from the Colorado River," Ulibarri said.

"The main piece is if there's not very much water in Lake Mead, which means there's not very much water in the Colorado River more generally," she said. "There are going to be cutbacks"

Water allocations from the Colorado River are subject to a strict agreement between seven western states.

"California is more or less at the top of the water rights hierarchy," she said.

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But she says California will need to conserve a lot more water, regardless of whether the state is a top priority for the resources.

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