Over 12.3 billion gallons of water stored in the Water Bank last year
SACRAMENTO—Sacramento-area water providers leveraged the historic winter storms of 2023 to boost groundwater levels through in-lieu recharge, banking over 12.3 billion gallons of water during the year, according to a new analysis from the Regional Water Authority (RWA), which represents nearly two dozen water providers serving 2.2 million people in the greater Sacramento region.
In-lieu recharge is the combined management of both surface water and groundwater use, resulting in the replenishment of groundwater supplies within the aquifers. Every gallon of surface water served to customers in lieu of groundwater results in water saved in the groundwater aquifer.
RWA’s analysis found that water providers opted for 70 percent surface water in 2023 (a very wet year) compared to 53 percent in 2022 (a very dry year). This substantial 17 percent shift allowed the groundwater aquifers to recover, resulting in nearly 38,000 acre-feet (over 12.3 billion gallons[1]) of water stored—enough to serve about 113,700 households[2] for a year.
“Mother Nature built the natural infrastructure, and we’re changing how we interact with it,” said RWA Executive Director Jim Peifer. “Using more surface water in wet years helps save underground water for future needs, similar to saving money in the bank for a dry spell. It’s about using what nature provides more abundantly at the moment while conserving other resources for when times are leaner.”
For over two decades, local water providers have utilized in-lieu recharge to store water in the region’s groundwater aquifers, resulting in significant increases in stored water and sustainable groundwater levels even during a megadrought. Some water providers are also equipped to store water through Aquifer Storage and Recovery (ASR), which allows them to deposit treated water into the groundwater aquifer during wet times using specially designed wells that can both recharge (inject) and recover (extract) water.
Now, efforts are underway to expand these practices through the Sacramento Regional Water Bank, which utilizes the region’s extensive groundwater aquifers to store excess surface water when available. The region’s aquifers can store twice the volume of water as Folsom Reservoir.
Optimizing the existing Water Bank infrastructure will make it possible to double the amount of water that can be stored to about 65,000 acre-feet of groundwater in wet years. And already-identified projects can triple recharge quantities to 90,000 acre-feet annually, serving about 270,000 households.
“The last two years have provided a case study for how our water system can be reoperated using existing infrastructure to harness a climate change-resilient water supply adapted to the extreme swings from dry to wet,” Peifer said. “And will be storing even more water with a fully functioning Water Bank.”
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Here’s what local water providers did to capture the storms in 2023:
- Sacramento Suburban Water District (SSWD): More than doubled the percentage of surface water served to its customers in 2023 compared to 2022, banking 18,772 acre-feet of groundwater in the aquifers, enough to meet the annual water needs of over 56,300 households.
- Sacramento County Water Agency (SCWA): Increased surface water use by 29 percent in 2023 compared to 2022, resulting in approximately 10,220 acre-feet of groundwater stored in the aquifers, enough to meet the annual water needs of more than 30,600 households.
- City of Sacramento: Increased surface water use by 26 percent in 2023 compared to 2022, resulting in nearly 6,800 acre-feet of water stored in the groundwater basin, enough water to serve 20,400 people.
- City of Roseville: Increased the amount of water stored by 22-fold, banking 2,134 acre-feet of water in 2023 (enough to serve over 6,400 households) through Aquifer Storage and Recovery compared to just 96 acre-feet in 2022, when surface water was limited due to dry conditions.
Other local water providers who are part of the Sacramento Regional Water Bank and will also shift between surface water and groundwater use include California American Water, Citrus Heights Water District, Fair Oaks Water District, Carmichael Water District, and Golden State Water Company.
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The Regional Water Authority (RWA) is a joint powers authority representing nearly two dozen water providers serving 2.2 million people in the greater Sacramento region. Formed in 2001, its primary mission is to help its members protect and enhance the reliability, availability, affordability and quality of water resources. Learn more at rwah2o.org.
[1] One acre-foot of water is equivalent to 325,851 gallons.
[2] Assumes one AF serves three households per year.