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Nearly all the lettuce in this country is grown with water from the Colorado River, which means a 19-year drought along the river has far-reaching implications. Neighboring states are still trying to come up with a deal by Thursday to avert a crisis. Lauren Sommer of member station KQED and NPR's energy and environment team reports.
LAUREN SOMMER, BYLINE: The Colorado River touches seven states, goes through the Grand Canyon and reaches the faucets of 40 million people from Denver to Los Angeles. But it starts as just a trickle high in the Colorado Rockies.
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BRAD UDALL: One of the cool things about a snowmelt is it's really efficient. I mean, and so it tends to all get in the river.
SOMMER: Brad Udall is a climate scientist at Colorado State University. And a few summers ago, we were at the very spot that runoff becomes a river. No question, the 19-year drought here has been bad. But climate change is making things worse.
UDALL: You heat up the climate, you are going to get fundamental impacts on the water cycle. We've known this for almost 50 years now.
SOMMER: A warmer atmosphere sucks up water, drawing it out of plants and soils. Udall says that means less runoff going into the river, potentially cutting the flow 20 percent by mid-century. Even today, states downstream are using more water than there is most years.
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BRENDA BURMAN: These are the lowest reservoir levels in my lifetime.
SOMMER: In December, Brenda Burman, commissioner of the U.S. Bureau of Reclamation, told everyone, find a solution.
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BURMAN: We are quickly running out of time.
SOMMER: States like California and Arizona have been negotiating a deal to share water, to cut back so reservoirs don't hit critical lows. And Burman said if they don't do it by January 31...
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BURMAN: We will act, if needed, to protect this basin.
SOMMER: But getting everyone to share water - that's the tricky part because of an invisible pecking order, the water rights system. It all depends on who started taking water first.
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UNIDENTIFIED NARRATOR: Another place where water is badly needed, the Californian desert.
SOMMER: One farming community in California, the Imperial Valley, has some of the oldest water rights.
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UNIDENTIFIED NARRATOR: Presently, it will be used by thousands of farmers, who will transform the arid desert into fields of green crops.
SOMMER: Today, the Imperial Valley uses more Colorado River water than Arizona and Nevada combined. And yet, if there's a shortage, they wouldn't have to give up water until almost everyone else has. But the drought deal being negotiated would require everyone to chip in.
BRUCE KUHN: We cannot give so much that we injure/cause harm to our community.
SOMMER: Bruce Kuhn is on the board of directors of the Imperial Irrigation District. He knows how tough these decisions can be. He was on the board in 2003, when, after decades of using more than its share, California was being forced to cut back. He voted to sell some of Imperial's water to San Diego as part of that deal.
KUHN: I was voted out of office over that vote. I was the swing vote. I lost friends, and I lost business associates over that.
SOMMER: Kuhn's customers were farmers who were not happy. Now Kuhn is back on the board with another water-sharing vote in front of him. At public meetings, some haven't let him forget the past.
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UNIDENTIFIED MEETING ATTENDEE: Bruce, how did that work for us?
SOMMER: The idea of sharing water doesn't go over well.
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UNIDENTIFIED MEETING ATTENDEE: This is a wrong deal. It's another chip away at our water right.
SOMMER: Kuhn and the other directors say they'll support the water-sharing plan if they're offered the right incentives. Kuhn hopes his friends will stay with him.
KUHN: One thing I will not lose this time, I will not lose customers. I sold my business a year ago.
SOMMER: Arizona still hasn't agreed to the deal yet either. If that doesn't happen by the end of January, the federal government says it will step in to decide the future of the Colorado River. For NPR News, I'm Lauren Sommer.