Central Valley irrigation intensifies rainfall, storms across the Southwest

Jan 28, 2013

Agricultural irrigation in California's Central Valley doubles the amount of water vapor pumped into the atmosphere, ratcheting up rainfall and powerful monsoons across the interior Southwest, according to a new study by UC Irvine scientists.

Moisture on the vast farm fields evaporates, is blown over the Sierra Nevada and dumps 15 percent more than average summer rain in numerous other states. Runoff to the Colorado River increases by 28 percent, and the Four Corners region experiences a 56 percent boost in runoff. While the additional water supply can be a good thing, the transport pattern also accelerates the severity of monsoons and other potentially destructive seasonal .

"If we stop irrigating in the Valley, we'll see a decrease in stream flow in the ," said climate hydrologist Jay Famiglietti, senior author on the paper, which will be published online Tuesday, Jan. 29, in the journal . The basin provides water for about 35 million people, including those in Los Angeles, Las Vegas and Phoenix. But the extra water vapor also accelerates normal , he said, "firing up" the annual storm cycle and drawing in more water vapor from the Gulf of Mexico as well as the Central Valley.

When the additional waves of moisture bump into developing monsoons, Famiglietti said, "it's like throwing fuel on a fire."

He and colleague Min-Hui Lo, a at the University of California Center for Hydrologic Modeling who is now at National Taiwan University, painstakingly entered regional irrigation levels into global rainfall and and traced the patterns.

"All percent differences in the paper are the differences between applying irrigation to the Central Valley and not applying it," Famiglietti said. "That's the point of the study – and the beauty of using computer models. You can isolate the phenomenon that you wish to explore, in this case, irrigation versus no irrigation."

Famiglietti's team plans to increase the scope of the work to track how major human water usage elsewhere in the world affects neighboring areas too. A better understanding of irrigation's impact on the changing climate and water availability could improve resource management in parched or flooded areas.

Explore further: New approach needed to deal with increased flood risk

Related Stories

Recommended for you

China says massive area of its soil polluted

1 hour ago

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

Book offers simplified guide to shale gas extraction

2 hours ago

The new book, "Science Beneath the Surface: A Very Short Guide to the Marcellus Shale," attempts to offer a reader-friendly, unbiased, scientific guide needed to make well-informed decisions regarding energy ...

New approach needed to deal with increased flood risk

2 hours ago

Considering the impacts of climate change on flood risk may not be effective unless current risk is managed better, according to new research from the University of Bristol published today in the Journal ...

Researchers question emergency water treatment guidelines

22 hours ago

The Environmental Protection Agency's (EPA's) recommendations for treating water after a natural disaster or other emergencies call for more chlorine bleach than is necessary to kill disease-causing pathogens ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Sean_W
1 / 5 (2) Jan 28, 2013
Go downwind of the farms and dig many shallow holes in the desert. Fill them with rock and gravel. Some of the water stays longer instead of running off in floods. Plant trees next to these holes.

Or just say that more rain and floods are caused by global climate warming change and leave it at that.

Either one is fine.
ROBTHEGOB
2.3 / 5 (3) Jan 29, 2013
Might explain the increase n rainfall in the Phoenix area the last few decades.

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

First radar vision for Copernicus

Launched on 3 April, ESA's Sentinel-1A satellite has already delivered its first radar images of Earth. They offer a tantalising glimpse of the kind of operational imagery that this new mission will provide ...

Image: Grand Canyon geology lessons on view

The Grand Canyon in northern Arizona is a favorite for astronauts shooting photos from the International Space Station, as well as one of the best-known tourist attractions in the world. The steep walls of ...

Book offers simplified guide to shale gas extraction

The new book, "Science Beneath the Surface: A Very Short Guide to the Marcellus Shale," attempts to offer a reader-friendly, unbiased, scientific guide needed to make well-informed decisions regarding energy ...

Net neutrality balancing act

Researchers in Italy, writing in the International Journal of Technology, Policy and Management have demonstrated that net neutrality benefits content creator and consumers without compromising provider innovation nor pr ...