As general manager of the Consolidated Irrigation District, which serves parts of Fresno, Tulare and Kings counties in the Central Valley, his job is to supply river water from the mountains to about 5,000 farmers, something he hasn’t done much of lately owing to the historic drought.
But as El Niño asserts itself, Desatoff has what at first glance seems like a head-scratching plan for the wet weather. Instead of steering Sierra flows through ditches and canals to crops like oranges, grapes and almonds, Desatoff plans to move water onto bare earth — in this case, a neatly graded 60-acre bowl of sand 15 miles east of Fresno.
Bucking the belief that dams are the only way to capture water, the irrigation district lets the precious liquid soak in at percolation sites so it stores in the ground. The agency introduced these “recharge ponds” to the region in the 1920s, and today is leading a popular charge.
Hoping for Wet Winter
This winter, dozens of water agencies across the state are counting on a drenching El Niño to produce surplus water to stash in the earth and make up for what’s been pumped out at unprecedented rates due to the recent absence of surface supplies.“We’re going to put as much water into the underground as we can,” said Desatoff above the roar of a bulldozer spreading sand at his percolation basin, set amid miles of sprawling farmland. “We got some rain clouds out here that we haven’t seen in three years, so we went out and got our loader to clean up these ponds.”
Desatoff is hoping to see a replay of what happened during the winter before the drought took hold. In the 2010-11 rainy season, so much water poured from the Sierra and down the Kings River that nourishes his district, he was able to fill the agency’s 50 recharge ponds for five months — until spring when the farmers needed the water for their crops.
Water Table Rises
At some spots, a foot and a half of water seeped into the ground each day, Desatoff said. In the end, more than 200,000 acre-feet of water permeated the aquifer — much more than the farmers pump out annually — and the water table across the district rose 7 feet on average, Desatoff estimated.At one percolation site, waves lapped so high onto an adjacent road that the California Highway Patrol called to tell him to stop filling the pond. Elsewhere, a woman complained that the water in the recharge basin was chasing snakes into her yard. At yet another site, a neighbor built a boat dock and moored a jet ski.
“I’d love to have those problems now,” Desatoff said, gazing at a still-dry bowl.
The likelihood that the drought won’t end this year —and that climate change might usher in a drier future — has put a lot of attention on water storage, particularly in farm country.
While at least four new dams and reservoirs have been proposed in California, the staggering $10 billion cumulative cost, and the relatively small 9 percent bump that would be expected in statewide storage, means agricultural communities must weigh other options.
By some estimates, storing water underground is six times cheaper than creating an equivalent amount of space behind a dam. And the increase in storage in California aquifers that have been swiftly drained with pumping could be at least five times what’s promised with the dam proposals.
“We’re seeing a surge in people interested in doing these projects,” said Ryan Jacobsen, executive director of the Fresno County Farm Bureau. “Folks want as much water in the ground as possible.”
State groundwater regulation, which requires water agencies for the first time to keep their aquifer levels in balance, is also driving interest in recharge programs. So is state bond money for water improvements: The latest $7.5 billion in funding, thanks to voter-approved Proposition 1, is yet to be doled out, but groundwater storage efforts are alongside dams in competing for cash.
“Recharge programs have generally been very successful,” said Abdul Khan, supervising engineer for the California Department of Water Resources, who monitors the health of the state’s aquifers. The problem, he said, is there just isn’t enough recharge to make up for groundwater depletion.
In some parts of the Central Valley, water tables have fallen 50 feet or more in the past five years, prompting wells to stop producing and even land to sink, dragging down roads and bridges. The collapsed aquifers in many cases can’t be resurrected to store water — or at least store as much as they did in the past.
“If we continue the way we are doing things right now without changing course, this depletion will be a catastrophe in the sense that we will have areas completely out of water and experience serious subsidence and serious water quality degradation,” Khan said.
Work to Expand Ponds
Although the aquifer beneath the Consolidated Irrigation District is in better shape than many, Desatoff is looking to expand his recharge efforts beyond the current 1,350 acres of percolation ponds.The goal, though, is complicated by rising real estate values in the Fresno area, he said, which make it hard to buy land for new basins. There’s also the $50,000 price tag of building a recharge pool, a big expense for a relatively small district.
But Desatoff is luckier than most in having sandy soil in the area, which draws water swiftly into the aquifer. Other water agencies have had to resort to pricey injection wells to drive water beneath stubborn deposits of clay.
Desatoff is also asking farmers to use private land as temporary percolation sites when they’re not growing crops. It’s a commonsense idea, given that water naturally soaks through the fields into the aquifer — albeit not as well as at a designated recharge basin with its soft ground and sandy berms.
But it’s a prospect that concerns some growers who wonder if the practice is healthy for their harvest.
“A lot of them would like to do recharge, but their argument against it is a good one: Am I leaching nutrients out of my soil that I’m paying to put back in?” Desatoff explained.
At UC Davis, a handful of researchers have begun studying ways to push water into the aquifer by flooding farms without hurting crops.
A preliminary test last spring at an alfalfa ranch in Siskiyou County found that while recharge might cause more weeds to grow, it didn’t harm the alfalfa. This year, the group is expanding its study to three almond orchards, one near Desatoff’s operation.
“I don’t see how we recover from this drought relying on just natural recharge,” said Helen Dahlke, the UC Davis hydrologist leading the farmland tests. “We definitely have to add artificial recharge if we want to achieve a sustainable situation.”
All Hinges on Rainfall
Of course, the wild card in all of this is wet weather, because to replenish the aquifers water managers need a supply above what is normally used. To this end, some agencies have begun routing storm water from nearby towns for recharge, while others are drawing on treated wastewater. At least one recently sought state approval to tap a creek.For Desatoff, successful recharge hinges on Sierra storms this winter, enough to fill Pine Flat Dam upstream on the Kings River for irrigation water come spring and then have surplus for the percolation ponds.
“If you’re a religious man, you might want to join me in church,” he said. “We need the rain. We need whatever help we can get.”
©2016 the San Francisco Chronicle Distributed by Tribune Content Agency, LLC.
