As Rains Soak California, Farmers Test How To Store Water Underground

Jan 12, 2017
Originally published on January 17, 2017 2:53 pm

Six years ago, Don Cameron, the general manager of Terranova Ranch, southwest of Fresno, Calif., did something that seemed kind of crazy.

He went out to a nearby river, which was running high because of recent rains, and he opened an irrigation gate. Water rushed down a canal and flooded hundreds of acres of vineyards — even though it was wintertime. The vineyards were quiet. Nothing was growing.

"We started in February, and we flooded grapes continuously, for the most part, until May," Cameron says.

Cameron was doing this because for years, he and his neighbors have been digging wells and pumping water out of the ground to irrigate their crops. That groundwater supply has been running low. "I became really concerned about it," Cameron says.

So his idea was pretty simple: Flood his fields and let gravity do the rest. Water would seep into the ground all the way to the aquifer.

The idea worked. Over four months, Cameron was able to flood his fields with a large amount of water — equivalent to water three feet deep across 1,000 acres. It all went into the ground, and it didn't harm his grapes.

These days, Cameron's unconventional idea has become a hot new trend in California's water management circles — especially this week, with rivers flooding all over the state.

"This is going to be the future for California," Cameron says. "If we don't store the water during flood periods, we're not going to make it through the droughts."

Helen Dahlke, a groundwater hydrologist at the University of California, Davis, is working with a half-dozen farmers who are ready to flood their fields this year. "We have test sites set up on almonds, pistachios and alfalfa, just to test how those crops tolerate water that we put on in the winter," she says.

There are two big reasons for these experiments.

The first is simply that California's aquifers are depleted. It got really bad during the recent drought, when farmers couldn't get much water from the state's surface reservoirs. They pumped so much groundwater that many wells ran dry. The water table in some areas dropped by 10, 20, or even 100 feet. Aquifers are especially depleted in the southern part of California's Central Valley, south of Fresno. Flooding fields could help the aquifers recover.

The second reason to put water underground is climate change.

California has always counted on snow, piling up in the Sierra Nevada mountains, to act as a giant water reservoir. Water is released gradually as the snow melts.

But because of a warming climate, California now is getting less snow in winter, and more rain. The trend is expected to intensify. But heavy rain isn't as useful because it quickly outstrips the capacity of the state's reservoirs and just runs into the ocean. Meanwhile, the state gets very little rain during the summer, when crops need water.

"We really have to find new ways of storing and capturing rainfall in the winter, when it's available," says Dahlke.

There's no better place to store water than underground. Over the years, California's farmers have extracted twice as much water from the state's aquifers as the total storage capacity of the state's dams and man-made lakes. In theory, farmers could replace that water.

Peter Gleick, a water expert and co-founder of the Pacific Institute, says that after winter storms, there is enough water available to recharge those groundwater aquifers.

The hard part, he says, will be getting the state's farmers and irrigation managers to go along with the plan. Because it will require flooding hundreds of thousands — and possibly millions — of acres.

"I'm cautiously optimistic that we can do this," he says. But it's going to require a different way of thinking. It's going to require a lot of farmers and owners of ag land to be willing to flood land when the water's available."

And Gleick says, even if this large-scale flooding can be accomplished, it won't be enough, by itself, to protect groundwater supplies. It will have to be accompanied by strict limits on how much water farmers can pump from aquifers. Groundwater — which until recently was almost completely unregulated — will have to be managed so that water is there when farmers really need it, when the rains don't fall.

Copyright 2017 NPR. To see more, visit http://www.npr.org/.

KELLY MCEVERS, HOST:

Here in California, rivers are flooding after all the rain we've been getting in the past few days, and more rain is on its way. California has, of course, been in a drought for five years. And cities and farms could benefit from all this water if they could find a way to store it. There's a new idea that an alliance of farmers, water experts and environmentalists are trying out - storing the water underground. NPR's Dan Charles reports.

DAN CHARLES, BYLINE: Six years ago, farmer Don Cameron did something that seemed kind of crazy. It was wintertime. Nothing was growing. And even though his crops didn't need any water, Cameron went out to a nearby river which was running high because it had been raining a lot, and he opened an irrigation gate. Water rushed down a canal and flooded hundreds of acres of vineyards.

DON CAMERON: We started in February, and we flooded grapes continuously for the most part until May.

CHARLES: Cameron was doing this because for years, he and his neighbors southwest of Fresno have been using wells, pumping water out of the ground to irrigate their crops, and that groundwater was running low.

CAMERON: We farmed out here for 35 years and have seen over time that the groundwater table had been declining. And I became really concerned about it.

CHARLES: So his idea was pretty simple - flood his fields and let gravity do the rest. Water would seep down into the ground, all the way to the aquifer. And in fact, it worked. These days, Cameron's crazy experiment is the hottest idea in California water management, especially this week, with rivers flooding all over the state.

CAMERON: This is going to be the future for California. If we don't store the water during flood periods, you know, we're not going to make it through the droughts.

CHARLES: Helen Dahlke, who's a water specialist at the University of California, Davis, is working with half a dozen farmers this year who are ready to flood their fields.

HELEN DAHLKE: We have test sites set up on almonds, pistachios, alfalfa just to test how these crops actually tolerate that water that we put on in the winter.

CHARLES: There are two big reasons for these experiments. The first is California's aquifers are depleted. It got really bad during the recent drought when farmers couldn't get much water from the state's surface reservoirs. They pumped so much groundwater that many wells ran dry. The water table in some areas dropped by 10, 20, even a hundred feet. Aquifers are especially depleted in the southern part of California's Central Valley, south of Fresno.

Flooding the fields could help a lot, but there's a second reason to put water underground. And it has to do with climate change. California's always counted on snow piling up in the Sierra Nevada Mountains as a kind of giant water reservoir. It releases water gradually as it melts, but California now is getting less snow in winter and more rain. And wintertime rain just runs away into the ocean.

DAHLKE: So we really have to find new ways of storing and capturing rainfall in the winter when it's available.

CHARLES: There's no better place to store water than underground. In theory, California's aquifers could hold more than twice as much water as all of its dams and manmade lakes. And Peter Gleick, a water expert and co-founder of the Pacific Institute, says there is enough water runoff available after winter storms to recharge those groundwater aquifers. The hard part will be getting the state's farmers and irrigation managers to go along with the plan because it will require flooding hundreds of thousands of acres, maybe millions of acres.

PETER GLEICK: I'm cautiously optimistic that we could do this, but it's going to require a different way of thinking. It's going to require a lot of farmers and owners of ag. land to be willing to flood land when the water's available.

CHARLES: And Gleick says even if this does happen, it won't do enough by itself to protect the groundwater. There also will have to be strict limits on how much farmers can pump from aquifers. They'll have to be managed so the water is there when farmers really need it, when the rains don't fall. Dan Charles, NPR News. Transcript provided by NPR, Copyright NPR.