Here’s an idea you can take to the bank: Saving water from a rainy day can help farming operations — as well as municipalities — get through the dry ones.

Excess water, much of it transferred to aquifers underground and out of view, is helping meet demand in California during a third drought year marked again by cutbacks in deliveries from the Sacramento-San Joaquin Delta.

Much of the water from wet years would otherwise flood farmland or go out to sea.

Players in the underground water banking business range from a family farming operation on Fresno County’s West Side to huge operations in Kern County associated with the Kern County Water Agency.

It’s unknown how many water banks — underground or otherwise — are in the state. Some say it could number over two dozen.

But the principle for their operation is basically the same as for conventional financial institutions. “It’s like storing money,” said Jim Beck, manager of the Kern County Water Agency, Bakersfield, Calif. “When you have a lot, you put it where you have access when you’re short money. The general philosophy is that we can deposit water in times of plenty.”

The agency is associated with 18 different water banking operations.

“There are more and more being developed all the time,” Beck said.

The Natural Resources Defense Council in 2007 found that more than 6 million acre-feet of water storage had been developed at six sites in the state since 1990.

“That’s far greater than people have acknowledged,” said Barry Nelson, a senior policy analyst for the council. “Much of the groundwater is out of sight, out of mind. Most of it is in the Kern Water Bank. We think there will be new groundwater storage, especially on the east side of the Valley. The (San Joaquin River Restoration) settlement with the Friant Water Users calls for that as part of the water management goal.”

Advantages to underground storage include avoiding evaporation, and it’s less likely to spark environmental skirmishes.

Nelson said it’s probable mostly due to costs that banking groundwater will be the preferred option when compared to building dams for surface storage.

But Beck is among those quick to say that the underground banks should be considered just one weapon in the arsenal for water warriors.

“When it comes to groundwater and surface water, we need both,” Beck said. “An advantage to surface water is that we can deliver large quantities in a short period of time. It’s harder to take water from the groundwater reservoir; it takes more energy and management.”

And Beck added that the banking system does not work “if we don’t solve the crisis of the Delta. Local farmers and water users have spent half a billion dollars in infrastructure to manage for high flow water and short water years. If we don’t have a solution that allows pumping to manage flow in high water years, it doesn’t work. If we don’t have the plumbing fixed, it’s like a swimming pool with no pipe.”

During the 1980s, water leaders in Kern County began developing groundwater banking programs to supplement inconsistent water supplies and provide more reliable water supplies during dry years.

“That’s the only thing that has kept us afloat the past couple of years,” said Fred Starrh, who has been farming for 55 years. He has been a member of the board of directors for the Kern County Water Agency for 25 years. He, two sons and a son-in-law operate Starrh Family Farm, which has nearly 9,000 acres of crops.

As the agency went down the path of banking, Starrh conceded, “there were naysayers” among the farmers. “But we knew it had to be done, we had to march ahead. With the environmental movement, every year more water was being taken out of the (federal water) project and run into the ocean.”

Today, he said, virtually all farmers are supportive, recognizing the fact that they can have access to water in the dry times. “In-lieu recharge” systems mean that farmers can pull out water without having to run their pumps. In high-water years, water users — such as the Santa Clara Valley Water District, well to the north of the Semitropic Storage District near Wasco — can send some of its Delta water down the California Aqueduct to Wasco.

It’s then put into percolation ponds to seep into the ground or given to Semitropic farmers who consume it instead of pumping groundwater. That allows the water table to rise over time.

Will Boschman, Semitropic’s general manager, said his agency benefits from the region’s geology. It’s located in a big basin where water can be stored in sand and gravel below the surface and kept in place by thick layers of clay and rock.

Martin Varga, engineering and groundwater services manager for Kern County Water Agency, said Kern Water Bank projects benefit both from geology and availability of water. He explained that the Kern Alluvial Fan is sandy and porous, allowing water to infiltrate from the Kern River. Other sources of water include the Friant Kern Canal, which carries water from Millerton Lake, and the California Aqueduct.

There are monetary costs for putting water banks into place, of course. And the infrastructure for getting water into the banks, as well as retrieving, are part of the cost of doing business, whether the customer is a city in Silicon Valley or a farmer on the West Side of the San Joaquin Valley. Users pay something to put the water in and to get it out.

The Kern Water Bank Authority, for example, has invested about $35 million in infrastructure that includes wells, canals, pump stations and pipelines.

Artificial groundwater recharge programs have been active in the Los Angeles Coastal Plain and Orange County since the 1950s and in Santa Clara and Alameda counties since the 1960s,” said Eric Senter, a senior engineering geologist with the California Department of Water Resources. “These are not groundwater banks in the sense of a put and take operation, but they are projects that actively recharge and manage groundwater for the purpose of increasing water supply and managing environmental problems such as seawater intrusion and land subsidence.”

Bakersfield’s 2,800-Acres Spreading Area was the first full-fledged banking project. In the 1990s, banking programs were expanded with the construction of the Kern Water Bank, which encompasses 20,000 acres of recharge ponds and habitat/wildlife land, and the agency’s 2,200 acre Pioneer Banking Project, which was created for groundwater recharge and recovery operations on the agency’s Pioneer Property.

Other banking projects include, in addition to Semitropic, the Kern Fan Area Operations, the Berrenda Mesa Water District/Kern County Water Agency Joint Groundwater Banking Project, Arvin-Edison Water Storage District’s groundwater banking project, the West Kern Water District/Buena Vista Water Storage District groundwater banking project, plus new groundwater district banking projects being initiated by Rosedale-Rio Bravo Water Storage District, Cawelo Water District and the Kern Delta Water District.

Beck said 30,000 undeveloped acres west of Bakersfield have been purchased for projects that would include groundwater recharge. “Acreage is increasingly being limited by explosive residential development,” he said.

There is now about 1.3 million acre feet of water in the ground in the Kern County system.

On the west side of Fresno County, Marvin Meyers has established a bank much smaller in scale than the Kern County operations. He said it can hold 20,000 acre feet and he hopes to develop it to 35,000 acre feet.

Meyers sees his little bank near the Mendota Pool as a key to keeping alive his family farming operation that is run by him, a son and a grandson. It was established in 2002 with no public funding and under close scrutiny of multiple agencies and environmentalists.

The cost was about $5 million. “I’m getting it back this year,” Meyers said.

The infrastructure included 27 monitoring wells.

During wet years “when the Kings River flows,” Meyers said, he can purchase water from willing sellers and also put in “re-scheduled water.”

It’s politically correct and acceptable,” he said, a way to avoid overdrafting native groundwater.

Meyers said he does not sell water from the bank. It’s mainly meant for use by the family farm, and if there is excess, he’ll work through water districts. He farms mostly in the San Luis Water District and some in the Westlands Water District, growing mostly almonds.

His water bank draws a lot of wildlife and has become an educational tool Meyers said the Central Unified School District gives for-credit classes on the wildlife habitat as part of the curriculum for third to twelfth grade students.

Banking partners who deliver or draw on Semitropic water include, in addition to the Santa Clara agency, the San Diego County Water Authority, the Alameda County Water District, Newhall Land and Farming Co., and the Poso Creek Water Co.

Poso Creek managing member Todd Henry said that company was formed three years ago by five growers whose crops are all permanent. Members farm in regions that include the huge Westlands district, Semitropic and Wheeler Ridge. They grow — in descending order — almonds, pistachios, citrus, cherries and grapes.

“We can not allow ourselves to go without water in any given year,” Henry said. “We recognized the threat that was before us regarding water supplies and decided, as a group, to invest in a groundwater banking project.

“This allows us to capture water in heavy rainfall years and extract it in scarce years like this year in order to protect our investment. We do not have the luxury of being able to fallow ground.”

Henry calls the system innovative and environmentally sensitive.

“We are sending water into an environmentally conscious groundwater banking unit,” he said. “It’s managed to everybody’s mutual benefit.”

Larry Wilson, a board member of the Santa Clara Valley Water District, echoes those sentiments.

But, like Beck, Wilson said the banking system is simply “another part of our portfolio of options.”

“It’s one more tool,” said Wilson, who is also a board member with the San Luis Delta Water Authority. “But you can’t put water in the ground if you don’t have the water to put in the ground, if you don’t have surface storage. You need both surface storage and groundwater.”