Projects evaluate recharge on cropland


Issue Date: October 24, 2018
By Christine Souza
At Costa Vineyards in Acampo, the farm’s owner has teamed with his water district and a nonprofit organization to examine the impact of flooding this 14-acre vineyard to recharge groundwater. In similar projects around the state, farmers and groundwater experts want to learn how such recharge efforts affect both aquifers and crops.
Photo/Christine Souza

Can water be spread onto active farmland to replenish underground aquifers without harming crops? That's the question under study in a variety of California locations on land holding vineyards, nut orchards, alfalfa and other crops.

These efforts, some of which have been ongoing for years, have become more important since the 2014 passage of the Sustainable Groundwater Management Act, which requires local agencies and groundwater users to develop plans to manage aquifers within their jurisdictions.

"Farmers and ranchers recognize that replenishing groundwater with on-farm recharge projects is one of the tools that we need to use to implement SGMA successfully," California Farm Bureau Federation Senior Counsel Jack Rice said.

One pilot project, at a zinfandel winegrape vineyard near Acampo, involves flooding 14 acres of the vineyard with up to 500 acre-feet of Mokelumne River water each year to recharge the underlying groundwater basin.

Landowner Al Costa is working with the North San Joaquin Water Conservation District and the nonprofit organization Sustainable Conservation on the project.

Costa's granddaughter, Tera Clark, said her family considers the vineyard a prime spot for groundwater recharge.

"My grandpa over the years was amazed at how fast the water would permeate the ground," Clark said. "He tried to contact some people to do a project because he said the water was needed and there was a good spot for the water to go straight down."

The current demonstration project on the Costa property, now in its second year, tests and promotes recharge in a district that receives little surface water and in which many farmers have converted crops to drip irrigation.

Dave Simpson, a director of the North San Joaquin Water Conservation District, said the district didn't deliver any surface water during the recent five years of drought, which led to increased groundwater use and to increased motivation for recharge.

Flooding the vineyard began in early October and is set to continue through early November.

Joe Choperena of Sustainable Conservation said the demonstration project aims to increase participation by other districts.

"Because this area and many other areas of California have critically overdrafted basins, this seems like a good way to maintain ag production but also utilize the landscape to recharge the aquifer," Choperena said. "This is one of six on-farm recharge monitoring sites, and the other monitoring sites are on almonds, other grapes—winegrapes and raisin grapes—walnuts and pistachios."

An early adopter of groundwater recharge, Don Cameron of Terranova Ranch in Fresno County, said he broke ground last week on a large-scale groundwater recharge project he has been pursuing for almost a decade through the state Department of Water Resources. Once completed, the project—a partnership among Terranova Ranch, Sustainable Conservation and the University of California, Davis—will add 30,000 acre-feet a month into the underground water system near the Kings River when floodwater is available.

In Northern California, professors from UC Davis are working on a small-scale study with the Scott Valley Irrigation District to recharge groundwater during winter months, in order to support added streamflow and fisheries, such as chinook salmon, during the summer. 

"We're not looking at recharging in this valley for us to consume as agriculture, because we get pretty much a full recharge of water," said farmer and rancher Jim Morris of Yreka, president of the Scott Valley Irrigation District. "We're looking at slowing the water down and allowing it to get back for fisheries purposes later."

With no real surface storage in the region, Morris said, trying to keep the river running through the valley can be tricky, so groundwater recharge could be an option.

UC Davis professor Thomas Harter said the Scott Valley project examines storing winter runoff underground in order to support late-summer streamflow.

Morris said the project is also looking at how added water in the wintertime will affect alfalfa.

"Alfalfa doesn't like to have its feet wet when it's growing," he said, "but can we do this in January, February and March, before the alfalfa breaks dormancy, without causing any adverse effects?"

Harter said studies around the state will gauge the impact of groundwater recharge on crops.

"Is there an agronomic disadvantage to putting floodwaters in an orchard or a vineyard or a fallow field? Those are questions that we need to address," he said.

Sustainable Conservation will hold a workshop about the Costa Vineyards project on Nov. 5, from 9 a.m. until noon, at the Woodbridge Winery Old Barrel Warehouse, 5950 East Woodbridge Road in Acampo. RSVP to groundwater@suscon.org or 209-408-0612.

"We are definitely trying to work on reaching sustainable groundwater levels in a way that does not impact the agricultural economy and communities and agricultural business," Choperena said.

(Christine Souza is an assistant editor of Ag Alert. She may be contacted at csouza@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.