Groundwater is a major source of irrigation water for California agriculture and is increasingly being managed and regulated to address the overdrafting of aquifers in many of the state’s groundwater basins. The ability to capture and store water for future use through groundwater recharge on existing farmlands has been demonstrated in recent years, and vineyard lands are proving to be good sites for groundwater recharge projects.
 
Sustainable Conservation is a San Francisco-based nonprofit organization founded in 1993 that has been involved in groundwater recharge projects and studies since 2011. Joe Choperena, Sustainable Conservation’s project director for Central Valley groundwater (GW) recharge, led a workshop in Lodi November 5 to introduce growers to current on-farm recharge projects and concepts, their potential benefits, and factors to consider in evaluating site suitability.

GW recharge is the practice of delivering stored surface water supplies that are more transient in availability and applying this water to land with high recharge suitability and good soil permeability. Recharge can successfully be done on dedicated land basins, on fallow fields, and on active croplands.

Choperena is involved with six current on-farm GW recharge monitoring projects in the Central Valley. Two involve winegrape vineyards—Costa Vineyards in Lodi, that hosted workshop participants at its demonstration site; and Terranova Ranch in Fresno County, managed by Don Cameron who is president of the California State Board of Food and Agriculture. The other projects are in a raisin grape vineyard in Fresno County, and in three nut crop orchards that produce pistachios, almonds and walnuts.

Choperena said Sustainable Conservation can assist growers with establishing GW recharge projects and in evaluating on-farm sites for suitability. Factors to consider include: on-farm engineering infrastructure, needs and costs to apply water; crop tolerance to flooding; soil suitability for recharge; water quality issues related to leaching of nitrates and salts; and surface water availability and water rights. Sustainable Conservation can also assist with monitoring and record-keeping, site mapping, policy and regulatory issues with state and local agencies, and obtaining incentives and funding for projects.

Choperena said, “We’re looking for other growers to partner with, and farms located in critically overdrafted groundwater basins are a priority.” Although more science is needed, based on current knowledge, Choperena said, “We’re confident that grapes are one of the best crops for groundwater recharge. They can tolerate having wet feet during the time of year recharge is applied, and they require less nitrogen and fertilizer than many crops, which can affect water quality issues.”

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