Managing water for farming on a large scale

California’s most recent drought has pushed farmers to become more water-use efficient

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The drought may be over but water continues to be a top-of-mind issue in California — particularly for its US$50 billion a year agriculture sector.

Most of the state’s rainfall happens in the north and most consumption in the agricultural and urbanized south, which has created a complex water distribution network anchored by two main projects: the federally funded Central Valley Project and the California State Water Project.

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Together, they irrigate close to four million acres of California farmland — and water distribution is dictated by a historic system of water rights tied directly to the land.

Why it matters: California supplies a significant portion of the Ontario market with fruits, vegetables and nuts and is a major competitor to Canadian producers.

California leads the U.S. in agricultural production, accounting for 13 per cent of the nation’s total farm gate value and producing more than 400 different commodities, including one third of all U.S. vegetables and two thirds of all U.S. fruits and nuts.

Water transported through the Sacramento-San Joaquin Delta, for example, is a partial or total drinking water source for two thirds of the state; at the same time, the San Joaquin Valley is considered to be the most productive agricultural region in the world. Three of its counties account for approximately US$21 billion in agricultural production.

Roland Fumasi.
photo: Lilian Schaer

“The San Joaquin Valley is essentially a desert with rainfall in the single digit inches so it depends on irrigation,” says Roland Fumasi, fruit, vegetable and tree nut analyst with Rabobank. “Fifty per cent of the available water flows through rivers naturally, filters, evaporates, goes to the Pacific Ocean etc., 40 per cent goes to agriculture and 10 per cent to municipal uses.”

According to Fumasi, there are more than 1,400 dams in California and most are more than 50 years old. The state’s population grew by 25 per cent in the last 10 years and is projected to reach nearly 60 million by 2050. This means more demand while increasing environmental regulation and activist pressure have halted construction of new infrastructure.

Competing demands for water were on stark display during California’s most recent drought, which lasted seven years and has been hailed as one of the worst to hit the state in 600 years, according to the California Department of Water Resources. And agriculture took a back seat, receiving starkly reduced water allocations and none at all during 2014-15, the two worst years of the drought.

“The first priority is people, then the environment and then agriculture, which is why agriculture got zero per cent in 2014-15 — that’s never happened before,” says Frances Mizuno, assistant executive director of the San Luis & Delta Mendota Water Authority.

An irrigation system set up for almond trees.
photo: Lilian Schaer

Even during the best of times, agriculture now only receives about 40 per cent of its water allocation, she adds, as a result of state legislation, such as the Endangered Species Act and the Clean Water Act.

California has also seen some dramatic shifts in its production as farmers exit out of row crops in favour of higher value and higher yielding — but also more water-hungry — permanent crops like fruits and nuts.

Harris Ranch and Farms in Coalinga, the largest family-owned agribusinesses in the U.S., is one such example. Originally growing mainly cotton and grains and then adding a wide range of fruit and vegetable crops — including more than 100,000 tons of processing tomatoes annually — the company has expanded heavily into nut crops in recent years to become Silk Almond Milk’s sole almond supplier.

At the height of the drought, they were one of the zero allocation farms, leaving them no choice but to draw from ground water supplies — their new wells now go down about 2,000 feet to access that water.

For Harris Executive Vice President William Bourdeau, who is also chair of the California Water District Alliance, water is a challenge, but it’s one he believes is more political than environmental.

“People can’t agree on how to use the resources, but they are abundant,” he says. “Being involved has opened my eyes to the complexity of the water situation in California. The conversation is complicated, but I’m hopeful we’ll find a solution.”

William Bourdeau.
photo: Lilian Schaer

For some, part of that solution means changing farming practices. Bowles Farming Company farms 11,500 irrigated acres in the San Joaquin Valley near Los Banos, most of which are now under drip irrigation. That’s a move that executive vice-president Derek Azevedo says has resulted in 25 to 50 per cent water savings as well as yield increases of 20 to 30 per cent depending on the crop.

Innovation is also emerging, like WaterBit, a cloud-based, automated irrigation system that supports variable rate water application, or an on-farm water accounting system developed by start-up Swiim Systems.

Swiim CEO Kevin France believes that growing municipal pressures will decrease agriculture’s access to water, so farmers have to do a better job with the water they do have.

Current agricultural water monitoring technology is antiquated and inaccurate. According to France, there can be a difference of up to 40 per cent between what farmers think they’re using and their actual water use. Swiim uses an accounting approach to track a farm’s complete water use, creating a financial statement of consumption that will help farmers comply with state rules.

“Some growers put yard sticks in the canal to estimate their use; we use regional data, flow meters and satellites to give users the ability to adjust their water efficiencies,” he explains, adding that new remote sensing technology also provides data on how much water a crop actually needs versus its current consumption.

“That’s powerful information to make real-time decisions,” he says. “After two seasons of working with us, growers are reporting higher yields and 20 to 30 per cent less water usage and they can prove their usage to state water agencies.”

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