Making Recharge a “Win-Win” for Landowners and Groundwater Agencies

The tenth anniversary of the Sustainable Groundwater Management Act (SGMA) last year put a spotlight on the challenges of implementing this landmark legislation. Agencies in both the San Joaquin and Sacramento Valleys have scaled up efforts to replenish aquifers in recent years, but they still need ways to better harness the water received in wet years.

Spreading water on privately owned land so it can penetrate the soil and refill below-ground aquifers-a process known as groundwater recharge-is one way to make the most of surplus water when it's available. This can include methods such as spreading water on farmland or on land that's set aside solely for recharge. Landowners may recharge using their own water and land, an irrigation district's water on their private land, or their own water on an irrigation district's land.

In a previous blog post, we explained how establishing groundwater accounting is a necessary first step for creating recharge incentives, and we explored several local agencies' accounting methods. In this post, we outline how these agencies incentivize landowners to conduct recharge.

Incentivizing groundwater recharge

Groundwater recharge incentive programs fit into two broad categories: monetary incentives and pumping credits. Monetary incentives are just what they sound like: a grower who recharges receives a monetary payment. Pumping credits are slightly different: in areas where groundwater pumping is limited, growers can receive credits to pump additional water if they conduct recharge on their land. We explore both types of incentives, using examples from specific agencies.

Monetary incentives. Recharge can be incentivized by paying landowners money for each acre-foot recharged. For example:

• Westlands and Arvin-Edison have both paid landowners to take surplus district water and recharge it on their land. These payments have ranged from $30-100 per acre-foot recharged.
• Pajaro Valley Water provides rebates on groundwater pumping fees for recharge. The rebate amounts to half of the current pumping fee, which is currently of $323-$452 per acre-foot.
• Westlands offers a hybrid incentive program that compensates landowners with a partial pumping credit combined with a monetary payment.

Pumping credits. Some groundwater sustainability agencies have groundwater allocations in place-that is, caps on the amount of groundwater that can be pumped each year per acre of irrigated land. Agencies with groundwater allocations use pumping credits to incentivize landowner recharge. Landowners who conduct recharge will receive 50-90% of the volume of the water they divert for that purpose as a credit for future pumping. These credits may appeal to farmers concerned about water reliability, because the credits increase how much groundwater they can pump in the future.

The share of water applied for recharge but not credited to the landowner is commonly referred to as the "leave-behind." The leave-behind accounts for the fact that not all water diverted for recharge makes it underground, and not all water that makes it underground stays put. The amount of leave-behind varies depending on physical factors such as how much water is lost to evaporation, how suitable the land is for recharge, and the time of year. Other factors include recharge method, surface water source, and recharge location.

Regardless of whether an agency uses pumping credits or monetary incentives, most agencies base the landowner's compensation on the amount of surface water diverted for recharge. If a district provides surface water for recharge, the groundwater sustainability agency-the local agency charged with implementing SGMA-typically uses district meter data to calculate the amount diverted. If floodwater or another surface water source is used for recharge, then the agency cannot depend on district data. In this case, landowners are typically required to meter their diversions and provide the meter data as evidence of their recharge.

Choosing the right incentive structure

Two factors help determine which incentive structure works best: whether or not the agency is using a tool like groundwater allocations or pumping fees to reduce pumping, and whether or not landowners have access to surface water.

For agencies with allocations in place, pumping credits are feasible to implement. In our 2023 survey of groundwater recharge in the San Joaquin Valley, we found that agencies with allocations were primed to receive floodwater diversions and were able to better take advantage of opportunities for recharge.

Some agencies without groundwater allocations in place, like Pajaro Valley Water, impose pumping fees. For such agencies, a rebate on fees based on amount of water recharged could be effective. If neither pumping allocations nor fees are in place, then a fixed monetary payment per acre-foot recharged may be most suitable, like that which Arvin-Edison employs. However, any agency could choose to provide fixed payments in addition to other incentives. For example, Westlands provides both pumping credits and fixed payments. Providing both pumping credits and monetary incentives may encourage more recharge by appealing to landowners in different situations.

Whether a landowner has access to surface water also matters. Landowners with surface water access can rely on existing conveyance infrastructure to move excess water to private land for recharge during wet periods. In some areas, most landowners may have access to district-provided surface water, but agencies have not yet set up pumping or monetary incentives. In that case, agencies may prefer to make fixed payments to landowners who take water for recharge during surplus conditions.

Developing good accounting systems is a prerequisite for managing groundwater demand, and it can also fast-track incentives for boosting groundwater supplies through recharge on private land. The agency approaches described here can help other agencies across the state develop their own programs while tailoring them to local conditions. Such programs can help the state capture more water during wet periods to help get through the dry periods in California's increasingly volatile climate.

This blog post is based on a review of publicly available documents and/or correspondence with managers of seven local water management agencies: Arvin-Edison Water Storage District, Lower Tule River Irrigation District Groundwater Sustainability Agency (GSA), Pixley Irrigation District GSA, the Madera County GSAs, Mid-Kaweah GSA, Westlands Water District GSA, and Pajaro Valley Water Management Agency (PV Water).