New Partnership Explores Groundwater Recharge

New Partnership Explores Groundwater Recharge

In the high-water year of 2011, Sustainable Conservation partnered with farmer Don Cameron of Terranova Ranch (Fresno County) to test the application of seasonal floodwater from the nearby Kings River onto active cropland (wine grapes) to help recharge the underlying aquifer.

In the high-water year of 2011, Sustainable Conservation partnered with grower Don Cameron of Terranova Ranch (Fresno County) to test the application of seasonal floodwater from the nearby Kings River onto active cropland (wine grapes) to help recharge the underlying aquifer.

The Almond Board of California and Sustainable Conservation, an organization that helps growers and other businesses protect the environment, have partnered to examine how orchards can play a part in recharging groundwater aquifers after years of drought.

“As the Almond Board started to really delve into the opportunity for groundwater recharge, we started to get to know Sustainable Conservation much better as an organization and the work they’ve been doing over the last few years in that field,” Almond Board President and CEO Richard Waycott says. “It very quickly became clear that our interests were very much aligned in looking at almond acreage and its potential to contribute to better groundwater aquifer management through intentional recharge.”

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As part of the project, three almond orchards – in Fresno, Stanislaus and Merced counties – have volunteered to undergo intentional flooding this winter to gain a better understanding of the agronomic impact on trees and yields.

“We hope to come out of this winter season with a better evaluation of how much, how often, and for how long surface water can be put on almond orchards and allowed to percolate down into the groundwater aquifers without causing any damage to the trees,” Waycott says.

Another component of the project involves working with a company called Land IQ, which uses satellite imagery and data to examine agricultural challenges. The Almond Board hired Land IQ to map all the almond orchards in California and overlay that map with soil and geological structure information. They then overlaid that with the existing irrigation districts and the capture and conveyance of water within the orchard areas.

“With that picture, [we’ll] start to understand better what the total potential is for groundwater recharge within the million-plus acres that are planted with almonds up and down the state,” Waycott says.

This map will illustrate the locations of high-potential soil structures that that would allow for faster percolation and recharge, as well as what kinds of capture and conveyance capabilities exist in those areas, Waycott adds.

Big Potential
Sustainable Conservation Executive Director Ashley Boren says education and outreach are another important piece of the puzzle. Sustainable Conservation will be spearheading efforts to spread the idea of intentional groundwater recharge to other ag and commodity associations in California.

In addition to the three almond orchards participating in the study this winter, Sustainable Conservation has lined up seven other demonstration sites across the Valley that will be accepting flood waters this winter and spring. “We think that grapes are a really good crop to take floodwaters,” Boren says, adding that stone fruit and cotton also have potential.

“If this idea of using active cropland for on-farm recharge – if we can prove it’s successful and doesn’t hurt the crop yields and their long-term health, we think this is a really promising strategy to help address the groundwater overdraft, particularly in the San Joaquin Valley that has some of the most severe overdraft in the state,” Boren says. “It’s not going to solve the problem, but it could make up a significant percentage of that overdraft.”

In fact, a study conducted by RMC Water and Environment conservatively estimates that, depending on soil composition, winter flood waters could make up as much as 20% of the annual overdraft. Further studies showed that if continued into the springtime, up to 33% of the average annual overdraft could be recouped. “It will vary county by county, but that could make a significant difference in trying to get these areas’ groundwater back into balance,” Boren says.

The Almond Board and Sustainable Conservation are also working to recruit more growers to experiment with high winter flows. “I think it’s a very significant opportunity,” Waycott says. “Being able to augment natural recharge with intentional recharge will be a very important piece of being able to maximize the flexibility and use of the different groundwater basins…Really learning how to much better manage our groundwater resources is key to the future of agriculture.”

Sidebar: Get Involved
Sustainable Conservation is seeking input from growers who have experience applying available excess flood water for on-farm groundwater recharge or who are interested in assessing the potential for groundwater recharge in their fields or orchards this winter.
Over the next few months, Sustainable Conservation is hoping to close the gap in available scientific information about the acceptable timing and duration of water being captured on farmland for recharge by confidentially interviewing growers with experience in the use of available excess flood water.

In addition, the organization is looking for farmers willing to use available excess floodwater during the winter of 2015-16 and allow researchers to confidentially monitor the amount of water recharged and assess crop condition and nutrient management.

The information will be used along with ongoing UC-Davis and Sustainable Conservation research on nitrate management to develop decision-support tools to guide other farmers in assessing the viability and suitability of their lands for on-farm groundwater recharge and also enable local Groundwater Sustainability Agencies to assess, in general, how on-farm recharge can contribute to achieving groundwater sustainability goals.

Growers interested in participating in the survey or demonstration plots should contact Joseph Choperena of Sustainable Conservation at 415-977-0380, ext. 320 or [email protected].