US Economy

California's new hot commodity: Stormwater

California growers flooding farms

On a drought-parched piece of land in California's Central Valley, farmer Don Cameron has persuaded other growers to do something counterintuitive.

Flood their farms.

"I think you could put millions of acre feet back into the ground," said Cameron, who grows everything from almonds and grapes to carrots and tomatoes.

Cameron has a novel idea: Flood fields with storm runoff from El Nino this winter when you don't need the water. Then let the water seep into the massive aquifer underground, raising the water table, so that it won't cost as much to pump in the summer when the water is needed.

You might even get other people to pay you to do it.

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Cameron has been thinking about the idea for a long time. During the huge storms of 1983, he saw a submerged vineyard survive. So in 2011, before the latest drought, Cameron diverted stormwater coming through his property to flood a 300-acre vineyard of wine grapes of moderate quality ("This is not Napa"). For five months in 2011, the vines stood in water more than a foot deep. "A lot of our neighbors thought we were crazy."

The experiment worked. Most of the water went into the aquifer underground. "We got probably 3,000 acre feet of water, which is a tremendous amount of water," and the vines and the grapes were fine, he said.

Now, he's spending $7 million to quadruple the capacity of a canal, hoping El Nino will provide even more water this time.

Don Cameron's flooded Vineyard.
Source: Don Cameron

Other growers have agreed to join him. Many feel they have to do something to replenish the aquifer, which has fallen to 250 feet beneath the surface of the ground. Much of the valley depends on that aquifer, and farmers — especially almond growers — have been accused of over-pumping.

Cameron is working to get the state's almond board and Sustainable Conservation, a California environmental nonprofit, to spearhead the large-scale flooding experiment. "We're looking to do 10 demonstration projects, not just almonds, but on other tree fruits and grapes as well," said Daniel Mountjoy, director of resource stewardship at Sustainable Conservation. "Some growers say they want to do it on 5 acres, some say they'll do it on 20, some say they'll do it on 150, 160 acres."

That's a new discussion that's going on in the state capital right now around, 'What are the rights to floodwater? ... No one's asked that question before.
Daniel Mountjoy
stainable Conservation

The fields need to be on sandy, porous soil, so the water can more easily seep underground. "During the winter season, you could have between 3 feet and 10 feet of water per acre," said Mountjoy.

The big question is what impact this will have on trees and fruit. "I think you have to be a little more careful with the almonds," said Cameron. "Some growers are concerned that if you have too much water, and you have a big windstorm during the winter, you could have trees blow over."

While some farmers are skeptical of something so completely new, they're also facing new state rules forcing them to account for how much groundwater they use. Putting rainwater into the aquifer could help them reduce their total usage.

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Then there's the potential market for storm runoff.

"That's a new discussion that's going on in the state capital right now around, 'What are the rights to floodwater?' Mountjoy said. "No one's asked that question before."

Most of the money Cameron is using to expand his canal is coming from a federal grant awarded for the prevention of flooding downstream. That has created a new conversation about storm runoff and its potential value. Mountjoy said incentives could eventually include compensation from communities downstream that do not have to build new levees to protect against flooding, or neighbors who benefit from more water underground in the same irrigation district.

"A lot of the growers looked at it as sort of a problem rather than an asset," said Cameron. "I mean, we're looking at reservoirs underneath our feet here that are potential areas to be refilled and stored for future use. It's a real asset for us."