April 17, 2017

Farmer Floods Fields to Recharge Groundwater Basin

Despite the recent drought-fueled criticisms of agricultural water use in the Golden State, the reality is California farmers are extremely efficient managers of this vital resource. Compared to 50 years ago, California farmers grow 43 percent more food using the same amount of water. Farmers are the original conservationists and constantly seek new ways to apply smart thinking to how they use water. While California agriculture was irresponsibly targeted by the media as the villains of the recent drought, in truth, the innovative efforts of farmers like Don Cameron of Terranova Ranch may hold the key to helping our state weather future droughts.

It is no secret that climate change is fundamentally changing how California must manage its increasingly scarce water resources.

Our state has historically depended on a system of reservoirs and canals to store and move water from northern California, where 75 percent of California’s precipitation falls – much of it as snow in the Sierra Nevada mountains – to central and southern California, where 75 percent of the population lives. As the snowpack melts during the spring and early summer, the gradual release of water has typically kept the reservoirs full and faucets flowing until the next rainy season.

However, as global temperatures rise, more of California’s precipitation is falling as rain instead of snow. While these periods of heavy rains can quickly fill our reservoirs, the additional flood waters are often wasted, simply flushed down the rivers and out to sea for lack of storage.

RECHARGING GROUNDWATER BASIN

The consensus among scientists and water managers alike is that California must find new ways of capturing and storing rain during flood events, and there is no better place to store water than underground. This is where forward-thinking farmers like Cameron, overseers of huge swaths of land sitting on top of drought-stressed aquifers up and down the state, can be recast as the heroes of the unfolding California water drama.

Six years ago, in 2011, Cameron did the unthinkable. During one particular period of high rains, he opened up his irrigation ditches and allowed the nearby swollen Kings River to run over hundreds of acres of vineyards on his farm. Over the course of the next four months, while his grapes lay dormant on the vines during the winter, Cameron continuously flooded his fields with one goal in mind: to recharge the groundwater basin that Terranova Farms and surrounding communities depend on during times of drought.

“There is a certain sense of irony in California agriculture’s shift to more efficient methods of irrigation, such as drip,” said Cameron. “The old method of flood irrigation was seen as wasteful, but it was better at restoring groundwater.”

At the time, the idea of flooding agricultural fields to store excess rains in underground aquifers was unproven, as were the potentially damaging effects the saturated soil might have on the roots of permanent crops.

“I think people thought we were crazy to be putting that much water on wine grapes for such a long period of time,” Cameron only half-jokingly mused.

WORKING TOGETHER FOR SUSTAINABLE WATER FUTURE

In partnership with Sustainable Conservation, an environmental group working with agriculture to recharge California’s groundwater supplies, Cameron was crazy enough to use his fields as a pilot project. As it turns out, the idea worked – aided by gravity, the water seeped through the soil and filled up the basin – and the grapes were unharmed.

Now, Sustainable Conservation, along with scientists from the University of California, Davis,  are working with more farmers like Don Cameron to test how different crops – such as almonds, pistachios and alfalfa – respond to being flooded during the winter. While not all farmland is suitable for groundwater recharge, as it requires the right mix of permeable soils and flood-resistant crops, there are currently 130 demonstration sites covering 16,000 acres in the San Joaquin Valley.

The results of these studies should prove Cameron’s intuition right, allowing farmers to play an increasingly significant role in storing surplus rains, helping to lead California toward a sustainable water future.