Independent, objective, nonpartisan research
Blog Post · June 21, 2023

Renewing California’s Groundwater: Ready, Set, Recharge!

photo - Recharge Water Flows through Pipe into a Planted Field, pixel-ca-dwr-2023_03_13_AI_0280_Groundwater_Recharge

As farmers and water managers scramble to funnel some of last winter’s abundant snow and rainfall into the ground, we spoke with two recharge experts: Daniel Mountjoy of Sustainable Conservation and Aaron Fukuda of the Tulare Irrigation District.

What changes have you seen this year compared to the wet years of 2017 and 2019? Are farmers more willing to put water on their fields?

Aaron Fukuda: For us, the unequivocal answer to that is “absolutely.” There has been a cultural change in irrigation practices, and we now have full-blown winter irrigation when historically the winter months were a farmer’s break time. Folks are now prepping their fields to take water in the dead of winter. So in the middle of last year’s floods, we weren’t flooding—we were recharging.

Within Tulare ID, the groundwater sustainability agency has established an allocation system and online tracking tool that has provided incentives to growers by crediting them with a percentage of the water recharged: 90% in the winter, and 75% in the summer.

Daniel Mountjoy: We’re totally seeing the change. Many more farmers are taking water during the winter, and in districts that weren’t ready, farmers are asking for it.

Are farmers putting water straight on their fields? Do they have on-farm basins?

AF: They’re having to come up with solutions in a hurry. We had some folks who don’t have flood irrigation systems anymore, so they put floodwater through their drip systems. It was a mess. But I give these guys a huge amount of respect—growers were helping each other out. The amount of buzz and optimism feels so good. One grower made a mess and flooded the roads—but nobody cared. Everybody laughed.

I have one grower who set up permanent berms that established a shallow basin on a 40-acre parcel. Now he’s got a hybrid farming/recharge basin. He planted it this year, but he sacrificed the crop—he’s going to recharge all summer long. That’s now his bank account for the rest of his acreage in dry years.

Tell us about the executive order from March (N-7-23), which increased flood diversion flexibility. How has it been going for the “white areas” that don’t have their own surface water?

DM: If you look at where the executive order (EO) has been activated, some of the biggest numbers were along the eastside bypass, which runs through the white areas of Madera and Merced counties where subsidence has been occurring. You can’t find a pump right now in the state of California: all the rented and purchased pumps are pulling water out of that bypass.

AF: In the Kaweah subbasin, we’re not using the EO. The Kaweah River is fully appropriated already, and every drop of water is brought out under a water right. I do worry about making the EO permanent because once we start codifying stuff in California, we tend to not get it right. The one-size-fits-all approach across California never works: every little stream has its own dynamics.

DM: Right. We don’t want to just duplicate the EO and say we’re done. We’ll end up having to do corrective legislation.

We urgently need to clarify rules for diverting floodwaters for recharge. It was unclear to most folks how the State Water Board’s permitting system was supposed to work for floodwater. The EO facilitated a lot of activity—at 60-some different locations. Let’s learn from this experience.

How did groundwater respond to different land uses and the flushing of legacy agricultural chemicals like nitrate? We certainly don’t want to worsen water quality, so let’s monitor those lands and then clarify where you can safely put water.

AF: Some of our communities are on bottled water because their wells are dry. Did we miss a precious opportunity to recharge because we feared it might cause nitrate to migrate into the groundwater supply?

DM: I’ll echo that. This needs to be a decision by groundwater sustainability agencies (GSAs) with their districts and affected communities. And there has to be a contingency plan in place in case they get it wrong.

We also need to think through requirements for environmental protection. Where are fish screens really needed? How much is too much water to take off? Some places need more protection than others.

What would you still like to see happen at the state and local levels?

DM: We need to clarify as a state what water is available for recharge. We rely on the water board’s 90/20 rule right now, but that’s not a biologically determined safe diversion level. My recommendation is that we use the California Environmental Flows Framework to determine when flood flows are acceptable to take.

Then we need to ensure that communities are at the table in programmatic recharge decisions by districts and GSAs. A lot more farmer-to-farmer knowledge exchange will also be key.

We also can’t just leave it to individuals. Recharge anywhere is helpful from a flood management perspective, but it’s better if it happens where it also benefits SGMA outcomes. That takes more of a regional planning approach, and it will only happen through incentives.

AF: It’s been a struggle as a GSA to balance planning requirements with actual implementation. But we’ve seen how motivated our growers are to figure out solutions when they know they can bank on the water they recharge. When you give the farmer an incentive, they jump on it right away—that’s just human nature. I’d like to see the state allow GSAs and water agencies some time to implement and evaluate because groundwater is not an instantaneous action and reaction—it takes seasons and years to adjust and prepare.


climate change Floods groundwater groundwater recharge infrastructure San Joaquin Valley Water Supply Water, Land & Air