Valley Voices

Flood Valley fields: Farmer incentives would pump up aquifer recharge

In the high-water year of 2011, Terranova Ranch in Fresno County tested the application of seasonal floodwater from the Kings River on wine grapes to help recharge the underlying aquifer. A significant amount of groundwater was captured without affecting crop yields.
In the high-water year of 2011, Terranova Ranch in Fresno County tested the application of seasonal floodwater from the Kings River on wine grapes to help recharge the underlying aquifer. A significant amount of groundwater was captured without affecting crop yields. Terranova Ranch

There’s strong evidence that the state’s crippling five-year drought may finally be coming to an end. Experts caution, however, that the state will see more frequent and intense droughts like the one we’re recovering from. When future rains do come, they’ll be more intense and result in more flooding.

While a vast majority of California’s reservoirs are full – some of the largest ran out of space to store this winter’s deluge – the drought’s long-term effects still persist. One of the biggest issues we face is depleted groundwater supplies. Groundwater keeps farms and communities going in times of drought and when surface-water supplies run thin.

This is especially true for much of the San Joaquin Valley, the nation’s most productive farming region, where groundwater levels have hit new lows. Farmers here had to pump nearly twice as much groundwater as they normally would to get through the last drought.

According to a recent Public Policy Institute of California (PPIC) report, “Water Stress and a Changing San Joaquin Valley,” over the last 30 years the San Joaquin Valley has been pumping out an average of nearly 2 million acre-feet more groundwater annually than gets put back into aquifers. An acre-foot, or 325,851 gallons, is about enough water to supply two households for a year.

This has had very serious impacts, from farmers having to drill deeper and more expensive wells, to thousands of shallower wells in the region going dry, to serious land subsidence and costly impacts to infrastructure like water canals.

The region urgently needs to capture and store floodwater underground in high-water years, like this one, using all means possible. Incentives need to be developed to accelerate adoption of solutions that maximize groundwater recharge.

As the PPIC points out, aside from establishing dedicated groundwater-recharge basins (many of which were at full capacity this year and couldn’t take on additional floodwater) and fallowing farmland, one of the easiest and cheapest ways to boost groundwater levels is spreading more floodwater onto active and fallow farmland to naturally recharge aquifers.

The California Department of Water Resources estimates that roughly 300,000 acre-feet per year of surface flows could be utilized for groundwater recharge – and much of that could be applied to cropland. Groundwater aquifers offer three times more storage capacity than all the state’s reservoirs combined, are cheaper to use than building new surface storage and can be utilized immediately.

What’s encouraging to us and our partners at the Almond Board of California, University of California, Davis, and Lawrence Berkeley National Laboratory is that more and more San Joaquin Valley farmers are signing up to test the promise of on-farm groundwater recharge.

In Fresno County, Double E Farms, owned and operated by father and son Russel and Matt Efird, will soon be applying available floodwater on their vineyards to recharge the underlying aquifer. Terranova Ranch plans to flood more than 1,000 acres of alfalfa, almonds, walnuts, pistachios, wine grapes and open ground prior to planting processing tomatoes.

In the high-water year of 2011, the year before California’s latest drought began, the ranch covered 1,000 acres of wine grapes in a cumulative average of 36 inches of floodwater from the Kings River without affecting crop yields.

But farmers can’t scale this promising solution on their own.

They need help from everyone with a stake in the region’s farming, water and economic future. This includes San Joaquin Valley irrigation districts, as well as state and federal water agencies, who can speed up the adoption of on-farm recharge by rewarding farmers for making deposits to the region’s underground water savings accounts.

Incentives include making low- or no-cost floodwater available to willing farmers and crediting farmers for the groundwater deposits they make in rainy years. Reservoir flood managers could work with groundwater agencies to release water earlier in winter so it could be captured rather than waiting to release peak flows that exceed what can be acquired by flooding farms.

Expediting water rights for recharged water and participating landowners should also be on the incentives list.

The future and health of the San Joaquin Valley’s farming sector, local communities and the environment depend on taking full advantage of this high-water year in preparation for the next drought we all know is coming.

Don Cameron is vice president and general manager of Terranova Ranch in Fresno County, which produces a mix of conventional, organic and biotech crops – He can be reached at

Ashley Boren is executive director of Sustainable Conservation, a Bay Area-based conservation nonprofit dedicated to helping California thrive by uniting people to tackle the toughest challenges facing the state’s land, air and water – She can be reached at