‘Crazy’ California farmer lauded for pioneering flooding of farm

Helm — 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 groundwater has become a model that policymakers 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With the drought-stricken state suddenly inundated by a series of rainstorms, California’s outdated infrastructure has let much of the stormwater drain into the Pacific Ocean.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 about 9.87-million cubic metres 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 neighbours 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 GM of Terra Nova Ranch, a 2,400ha farm growing wine grapes, almonds, walnuts, pistachios, olives and other crops in the San Joaquin Valley, the heart of California’s $50bn 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 the US state 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 46cm-105cm of water, Cameron said. He plans to eventually flood 214ha of pistachio trees and 61ha of wine grapes, plus another 142ha that are planted only when excess floodwater is available.

The state department of water resources provided $5m and Terra Nova another $8m for the project, which includes a pumping system. So far, there has been almost 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 neighbours,” Cameron said.

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

Since then, policymakers have worked on economic incentives for more farmers to follow suit. Some water districts that are responsible for implementing the SGMA have offered growers credits towards 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 in 2023, returning at least 15,200 acre-metres back into the ground by mid-February.

California, which has a strategic goal of adding 1.2-million acre-metres of storage, recently provided $260m in grants to Groundwater Sustainability Agencies established under SGMA. The state received applications seeking $800m, 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 fertilisers 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  303,514ha to 404,686ha of irrigated farmland would have to be fallowed, Mountjoy said.

“We’re at the beginning of a lot of momentum for groundwater recharge programmes,” said Gosselin, of the state groundwater office. “The last two years [of extreme drought] was a wake-up call for everybody.” 

Reuters