With torrential rains battering California, state water regulators have approved a plan to divert water from the San Joaquin River to replenish groundwater depleted by heavy agricultural pumping during three years of record drought.
The State Water Resources Control Board has approved an application by the US Office of Reclamation to take more than 600,000 acre-feet of the river and send much of that water to areas where it can spread, soak into the soil, and seep. to the aquifer below the San Joaquin Valley.
The amount of water to be diverted under the plan is greater than the annual supply for the City of Los Angeles. Some of the water will also be sent to wildlife refuges along the San Joaquin River starting next week, officials said.
The plan is intended to address potential flood risks, capitalize on California’s near-record snowpack, and capture some of the high flows from recent extreme storms to store water underground.
“We are taking steps to maximize groundwater recharge in a way the state of California has never done before,” said Erik Ekdahl, deputy director of the State Water Board’s division of water rights. “This is a tremendous opportunity to help recharge these depleted aquifers.”
State officials said their order allows the Office of Reclamation to manage flood flows from Friant Dam and change the points where water is diverted along the San Joaquin River.
Where water sinks into the ground and replenishes the aquifer, it could help address declines in water levels that have left families with dry wells in rural areas throughout the Central Valley. Stabilizing water levels could also help alleviate the widespread problem of landslides caused by over-pumping, which has caused costly damage to canals and other infrastructure.
Gov. Gavin Newsom said after the driest three years in state history, “California is taking decisive action to capture and store water for when dry conditions return.”
Newsom has sought to prioritize stormwater capture and groundwater recharge as centerpieces of his administration’s strategy to adapt to more intense water extremes with climate change. On Friday, the governor’s office announced that it had signed an executive order allowing the capture of water from the latest round of storms.
The Recovery Office manages the dams, reservoirs and canals of the Central Valley Project and sends water to contractors, including large agricultural irrigation districts and other agencies. The state order allows the federal government to deliver floodwater from the Mendota Poola small reservoir on the San Joaquin River, which will be used to replenish groundwater.
The water, which otherwise would have flowed down the San Joaquin River, be available for irrigation districts and other agencies to divert to replenish groundwater for more than four months. Under temporary contracts with the Federal Government, they will be able to send water through canals to areas with permeable soils that allow groundwater recharge.
Some flooding will also reach wildlife refuges, including the San Luis National Wildlife Refuge, Mendota Wildlife Area, and Los Baños Wildlife Area.
The State Water Board said in its order that the changes will capture “high flows that would otherwise go unused,” easing pressures on flood control infrastructure and helping to address chronic declines in groundwater levels.
Environmental groups, including the Natural Resources Defense Council and the Bahia Institute, opposed the plan, saying in a letter that the water diversions would allow for lower flows in the San Joaquin River than anticipated in a 2006 legal agreement, and would likely be detrimental to Chinook salmon.
“While the order does not completely dry up the San Joaquin River, it will divert most of the water that was supposed to flow downstream under the court-approved settlement agreement, primarily to benefit corporate agribusiness in the Westlands Water District. said Doug Obegi, senior counsel for the Natural Resources Defense Council. “Once again, agribusiness wins while the environment receives less than its fair share of water.”
Amanda Fencl, chief climate scientist at the nonprofit Union of Concerned Scientists, said the plan raises questions about who will benefit most, especially since many water contracts in the area are held by agricultural irrigation districts.
“It is essential to recharge the aquifers, especially when there is an influx of rain,” Fencl said. “But I still have an open question about whether other water users, such as households with domestic wells and community water systems, will benefit.”
State officials disagreed with objections raised by environmental groups, saying the water diversions will not harm the environment and that the flows remaining in the river will meet the requirements.
“There will still be a lot of water moving up the San Joaquin,” Ekdahl said. “The amount of water that will be redirected here is still relatively low compared to the amount of water that will flow in the system.”
The Newsom administration and the federal government drew criticism from environmental groups for another decision last month, when they asked the State Water Board to temporarily suspend water quality rules in the Sacramento-San Joaquin River Delta in an effort to Store more water in reservoirs. The board ended that exemption Thursday, saying recent rains and snow no longer make it necessary.
Newsom set a goal last year, as part of his water supply plan, to increase average annual groundwater recharge by about 500,000 acre-feet. The State Water Board said that since December it has approved the diversion of about 790,000 acre-feet of water for groundwater replenishment, as well as supplies for wildlife refuges.
Most of the water pumped from Central Valley wells supplies farms that grow a wide variety of crops, from almonds to tangerines.
Scientists found in a recent study that the depletion of groundwater in the valley has accelerated in recent years. They estimated that groundwater losses since 2003 totaled about 36 million acre-feet, or about 1.3 times the total water storage capacity of Lake Mead, the nation’s largest reservoir.
As state officials have increasingly prioritized aquifer recharge, they have noted that there is vast underground storage space available and that replenishing groundwater is one of the easiest and cheapest ways to take advantage of wet years.
Local water agencies have begun planning recharge projects as they begin to implement plans to curb overpumping, as required by the state’s 2014 Sustainable Groundwater Management Act.
There has also been an increasing focus among water officials on finding ways to ease the permitting process to use stormwater to recharge aquifers and strategically investing in infrastructure to move water to areas where permeable soils create rapid pathways to the underground water.
The State Water Board said the single federal government application cleared the way for large-scale recharge without the need to approve numerous smaller permits.
The water used to replenish the aquifer will help local agencies move toward goals of addressing overpumping under the groundwater law, said Thomas Harter, a professor of water resources at UC Davis.
Harter said that 600,000 acre-feet is “a significant portion, and certainly an important stepping stone toward future wet years and reaching these goals.” He said that water stored underground may allow eventual cuts in well water use to be somewhat less severe than the reductions should be.
“To the extent that we can increase the supply, and we can only do that by capturing these large flood flows and storing them, that’s our main card in this game,” Harter said. “It won’t eliminate the need to reduce demand, but it will lessen the need to do so.”
Ann Willis, California regional director for the American Rivers group, said she believes the newly approved plan is a good approach to recharging severely depleted groundwater.
“It speeds up the regulatory process to take advantage of these higher flows when they are available,” Willis said. “It’s a positive thing that we’re doing this, and I think we’re going to learn a lot from it.”
He said the minimum river flow required by the permit appears too low to support a healthy San Joaquin River, but flow gauges have recorded rising flows above that level.
“I think right now we have enough water to do both: recharge and environmental flows,” Willis said. “But that’s not always true. And we must take into account which of those objectives we prioritize when there is not enough water for everyone.”
While the state takes advantage of storms to store water underground, efforts to rebuild depleted groundwater reserves will take time, said Karla Nemeth, director of the California Department of Water Resources. She said state officials are working with local agencies to expand these efforts and improve the permitting process for more recharge projects.
“Hopefully over the course of this next series of storms, we’ll be able to identify those projects and activate those recharge systems,” Nemeth said. “We know that dry conditions will return to California, and it’s really these moments that we need to capture, so that we can be resilient in the event of future dry conditions.”
Times staff writer Hayley Smith contributed to this report.