With the recent announcement that the drought in Northern California is officially over, and reservoirs, ponds and streams in many parts of the state filled to capacity and overflowing, many farmers and officials are asking, what do we do now?
What they mean is how can they take advantage of these flush times? California has always been subject to swings between droughts and floods. Much of the current flooding is going into rivers and out to sea. As California Farm Bureau Federation president Paul Wenger noted, "All the water we've prayed for is just going down the drain, so to speak. What if we could harness the water and store it for future use?"
One solution being proposed by state officials would be the construction of new aboveground water-storage facilities: more ponds, lakes, and reservoirs. But, "reservoirs offer a 20th-century answer to a 21st-century problem," said Kyle Jones, of the Sierra Club California. "We're gonna have to look at more innovative ways to create and store new water supplies." The major problem with reservoirs? Evaporation. In dry times, a lot of water is lost.
But what if flood waters could replenish underground supplies? Don Cameron, a Central Valley farmer and general manager of Terranova Ranch, Inc., is trying to do just that.
For years, Cameron, whose company is headquartered near Fresno at the southern end of the San Joaquin Valley, has handled irrigation like most of his neighbors, pumping water out of underground aquifers to water crops. He knew the groundwater table was declining to dangerously low levels.
Back in the 1980s, Cameron was driving to work one day when he noticed a small flooded vineyard by the side of the highway. "Back in '82, '83, we had a big El Niño year," Cameron told Wine Spectator. "I used to drive along the San Joaquin River on the way to work and I noticed a vineyard where the vines were nearly under water until July. I made a mental note. I knew that grape vines were very tolerant to having wet feet as long as the water was cold and had a good oxygen content."
"When the water finally did go down," said Cameron, "the vines were fine and they harvested the grapes. I got the idea there was a possibility that we could do controlled flooding in our vineyard and recharge the groundwater." Cameron hoped that the water in the vineyard might eventually filter down through the soil into the underlying aquifer.
Cameron experimented with flooding his land over the years, but in 2010 he secured a grant to do something more formal the following year. "We put measuring devices out in the field. We wanted to know how much surface water we could apply without causing damage to the vines. We were able to flood until the end of May or early June without any damage. As long as the water we applied remained cold, the vines grew normally."
"Just how much of that water filtered down into the aquifer?" asked Cameron. "The vines were using some of that water and we lost some to evaporation and transpiration. [But moisture meters] found that 70 percent of the water applied found its way below the root zone of the vines and on its way to the aquifer."
Cameron's idea seems to be gaining notice. Helen Dahlke, a hydrologist at UC Davis, has set up six experimental sites around the state to test how other crops tolerate standing water, and is hoping to establish a large-scale Central Valley vineyard project. "There is no real scientific study done on testing the effects of winter recharge of underground aquifers," she said.
Last week, Cameron spoke to a group of Lodi growers interested in promoting groundwater recharge in their region. "Right now in California the reservoirs are full and they are releasing water, creating flood problems," he said. "But we have storage underground and we can store the water for future use."