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Colorado River May Not Meet Supply Needs

The white 'bathtub ring' on the rocks along the Colorado River is from minera...

Photo by Ethan Miller

Above: The white 'bathtub ring' on the rocks along the Colorado River is from mineral deposits left by higher levels of water. A seven year drought and increased water demand spurred by explosive population growth in the Southwest has caused the water level to drop over 100 feet to its lowest level since the 1960s.

— The Colorado River system supplies water to tens of millions of people and millions of acres of farmland. But researchers at UCSD say climate change will likely mean the river won't meet future demands. As KPBS Reporter Ed Joyce tells us, those supply problems could come in less than 15 years.

Scripps Institution of Oceanography marine physicist Tim Barnett says he and Scripps climate researcher David Pierce wanted to answer one question.

"Are we going to be able to deliver the water out of the Colorado as is currently promised?" Barnett asks. "And with any climate-change at all or a reversion of the Colorado back to its historical flow rates, the answer to that question is no."

Even under conservative climate change scenarios, Barnett says reductions in the runoff that feeds the Colorado River could mean a shortfall in the annual water supply for about 800,000 homes roughly every other year by 2025.

By the latter part of this century, those numbers double.

"The thing that we did not discuss and did not include in the study was population growth", Barnett said. "So they're talking about packing another 30 million or so people into the Southwest here over the next 20 years. It would take something like a quarter to a third of the current flow of the Colorado to satisfy those people's needs. So somebody's not going to get water that's getting it today, I guess that's the bottom line here."

He says there are ways to manage the supply wisely to prevent shortages.

"One of them would be to stop building these mammoth cities in the middle of the desert where there isn't any water, that sort of defies logic," Barnett said. "But the politicians don't seem to want to touch that one. And conservation measures."

Barnett says conservation and long-term planning are needed now to make the Colorado river system sustainable in the future.

Ed Joyce, KPBS News.

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