Farmers flood their fields in order to save them

When Don Cameron first intentionally flooded his central California farm in 2011, pumping excess stormwater onto his fields, fellow growers told him he was crazy.

Today, California water experts see Cameron as a pioneer. His experiment to control flooding and replenish the ground water has become a model that policy makers say others should emulate.

With the drought-stricken state suddenly inundated by a series of rainstorms, California’s outdated infrastructure has let much of the stormwater drain into the Pacific Ocean. Cameron estimated his operation is returning 8,000 to 9,000 acre-feet of water back to the ground monthly during this exceptionally wet year, from both rainwater and melted snowpack. That would be enough water for 16,000 to 18,000 urban households in a year.

“When we started doing this, our neighbors thought we were absolutely crazy. Everyone we talked to thought we would kill the crop. And lo and behold, believe me, it turned out great,” said Cameron, vice president and general manager of Terra Nova Ranch, a 6,000-acre (2,400-hectare) farm growing wine grapes, almonds, walnuts, pistachios, olives and other crops in the San Joaquin Valley, the heart of California’s $50 billion agricultural industry.

If more farmers would inundate their fields rather than divert precipitation into flood channels, that excess could seep underground and get stored for when drought conditions return.

California swings between disastrous drought and raging floodwaters. This season has been especially rainy, with 12 atmospheric rivers pounding California since late December, placing greater importance on flood control. More wet weather is forecast in the coming week.

Terra Nova’s basins are filled with 1.5 to 3.5 feet of water, Cameron said Wednesday. He plans to eventually flood 530 acres of pistachio trees and 150 acres of wine grapes plus another 350 acres that are planted only when excess floodwater is available.

The state Department of Water Resources provided $5 million and Terra Nova another $8 million for the project, which includes a pumping system. So far there has been virtually zero return for the company, Cameron said, though it may acquire future water rights for its groundwater contributions.

Cameron “is definitely what we call the godfather of on-farm recharge. He’s really the pioneer who began doing it first,” said Ashley Boren, CEO of Sustainable Conservation, an environmental group with a focus on supporting sustainable groundwater management.

This mimicking of nature – letting water flow across the landscape – is the most cost-effective way to manage peak flood flows, experts say, while banking the surplus for drier days.

“It’s not only going to benefit us, it will benefit our neighbors,” Cameron said.

Cameron began his 30-year-old passion project before the state passed the Sustainable Groundwater Management Act (SGMA) of 2014, a law that sought to avoid a looming disaster from overdrafts.

Since then, policy makers have worked on economic incentives for more farmers to follow suit. Some water districts that are responsible for implementing SGMA have offered growers credits toward water rights in exchange for recharge. Pending state legislation would simplify permitting and guarantee water rights for participating growers.

California Governor Gavin Newsom signed an executive order on March 10 making it easier for farmers to divert floodwaters onto their lands until June.

There is no statewide monitoring of on-farm recharge, but Sustainable Conservation is keeping track of four water districts in the San Joaquin Valley that recorded 260 farmers replenishing their aquifers this year, returning at least 50,000 acre-feet (61.7 million cubic meters) back into the ground as of mid-February.

California, which has a strategic goal of adding 4 million acre-feet of storage, recently provided $260 million in grants to Groundwater Sustainability Agencies established under SGMA. The state received applications seeking $800 million, indicating demand for projects, said Paul Gosselin, deputy director of the state’s Sustainable Groundwater Management Office.

Besides cost, growers face other obstacles to on-farm recharge. A farm must have access to the water, cannot hurt endangered species and cannot flood land subjected to certain fertilizers or pesticides or dairy farm waste.

In the Merced River Watershed, willing farmers could recapture enough future floodwater to replace 31% of the groundwater they are overdrafting under existing conditions, said Daniel Mountjoy, director of resource stewardship for Sustainable Conservation, who participated in a state study. That could jump to 63% with changes in reservoir management and infrastructure improvements, he said.

To achieve sustainability throughout the San Joaquin Valley, an estimated 750,000 to 1 million acres of irrigated farmland would have to be fallowed, Mountjoy said.

“We’re at the beginning of a lot of momentum for groundwater recharge programs,” said Gosselin, of the state groundwater office. “The last two years (of extreme drought) was a wakeup call for everybody.”