State fast-tracks groundwater recharge project to capture flood waters

The Department of Water Resources (DWR) is partnering with the State Water Resources Control Board to fast-track efforts to capture flood waters to recharge groundwater basins. Water captured during extreme wet periods such as the one California is now experiencing will be stored in groundwater basins for use during dry periods.

“The State is capturing more water supply by accelerating groundwater recharge permitting and projects that mitigate the impacts of prolonged drought and support long-term sustainable groundwater management,” said DWR Director Karla Nemeth. “Projects that capture available precipitation, stormwater, or floodwaters to recharge depleted groundwater basins need to be ready to capture high flows when they are available during each wet season, typically October through April in California.”

The pilot program began in August 2022 with an application from the Merced Irrigation District and the Merced Irrigation-Urban Groundwater Sustainability Agency to divert and store water from the Mariposa creek. The permit application authorizes diversion of up to 10,000 acre-feet of water from the creek during periods of high flows that would otherwise likely flow through the system.

“The review process for these permits is complex and must consider impacts to the environment and existing water rights, including those dependent on specific Delta conditions and state and federal water project requirements,” said State Water Board Chair Joaquin Esquivel. “In acknowledgement of this complexity, we have streamlined the process so we issue them in a timely way and help local agencies succeed in capturing stormwater for recharge and bringing stressed groundwater basins into balance.”

Since 2016, the State Water Board has approved 20 temporary permits. Currently there are five applications pending, with two more projected to be approved next week. The remaining three are going through a public noticing process.

The Merced Project’s permit includes multiple points of diversion. Diversions will be directed to a number of agricultural fields to support groundwater recharge consistent with the Merced Subbasin Groundwater Sustainability Plan. Water diverted for recharge purposes will be applied to working agricultural lands only, and water stored will be accounted for in the upcoming growing season as the first irrigation water to be pumped from the aquifers.

“Merced Irrigation District is excited to partner with DWR supporting GSAs with this crucial pilot project intended to help groundwater basins become sustainable by turning potential flood waters into groundwater recharge opportunities,” said Hicham Eltal, Deputy General Manager, Merced Irrigation District. “The project is intended to show that the subsidence being experienced in part of the Merced Groundwater Basin along the San Joaquin River can be addressed while simultaneously reducing recurring flood events from local creeks tributary to the San Joaquin River. The goal is that this effort paves the way for acquiring temporary permits to divert flood flows by GSAs throughout the State to help groundwater basins reach sustainability.”