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Ringside: How to Add 10 Million Acre Feet Per Year to California’s Water Supply

californiaglobe.com
There is a good chance that a Californian is going to be nominated to become the new Commissioner of the Bureau of Reclamation. One source of opposition to his confirmation could be senators representing states that share with California the waters of the Colorado River, concerned that a Californian will not sufficiently take into account their interests. But if California invests in projects to increase its water supply, it won’t need as much water from the Colorado River.

What follows are ways California, and only California, has the potential to increase its annual water supply by 10 million acre feet per year. That’s enough to cope with a prolonged drought without starving cities or farms of water. It’s also enough to make generous deals with the other states that withdraw water from the Colorado River.…

Read the full article at californiaglobe.com

Irrigation districts look to EPA for crystal clear WOTUS rule

Capital Press
With the political winds at their backs, farm groups and irrigation districts are seeking to ensure the Clean Water Act definition of “waters of the United States” excludes irrigation canals and ditches.

Irrigation districts have not fallen under the act’s jurisdiction in the past, and the U.S. Supreme Court’s Sackett v. EPA decision supports keeping it that way, said Greg Morrison, executive vice president of the National Water Resources Association, whose members include irrigation districts in Washington, Oregon and other Western states.…

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Wet Season’s end for Water Year 2025

californiawaterblog.com
California’s Water Year runs from October 1 of the previous calendar year through September 30.  California’s “wet” season is traditionally October 1 – April 1.  The rest of the year (and often parts of the “wet” season) is usually dry.  We can get major storms into April, but often not.

So almost all of this Water Year’s precipitation has fallen already.…

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The trouble with Newsom’s ploy to spare California in Trump’s trade war

Sacramento Bee
Gov. Gavin Newsom has the right political instincts as he seeks to insulate California from the potential economic catastrophe of a tax war on global trade, seeking to spare the state from retaliatory tariffs. Unfortunately, it just won’t work.

Sadly for California, this is a moment when Newsom would actually have to be the president to effect change. As big as we are, California is not an island when it comes to trade. Our ports unload an estimated 40% of all containers that arrive in this nation from somewhere else. And nobody really tracks where it ends up.…

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Mapped: What a barrage of 56 West Coast atmospheric river events looks like

foxweather.com
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As the peak of the snowmelt season begins to slow down, the majority of California’s major reservoirs are at least 90% full – a promising sign for a state that frequently battles drought and associated wildfires.
SACRAMENTO, Calif. – The previous six months have proven to be a tale of the haves and have-nots when it comes to atmospheric river events impacting the West Coast.
According to data from the Scripps Institution of Oceanography, 56 atmospheric rivers impacted the western U.S. during late 2024 and early 2025, with the majority affecting Oregon and Northern California.
Atmospheric rivers are long, narrow corridors of concentrated moisture that transport air from tropical regions and release precipitation over generally cooler areas. According to NOAA, these features typically range from 250 to 400 miles wide and can stretch over 1,000 miles in length.
Forecasters note that Northern California typically experiences about six strong atmospheric rivers every year, but by April 1, that number had already reached nine.
This increase in storm system intensity and frequency led to above-normal precipitation levels, particularly in critical watershed zones, but, in contrast, Southern California saw very few significant storms, receiving only a handful of weak systems.
2024-2025 atmospheric river events
(FOX Weather)
As a result, precipitation totals in Southern California dropped to 70% or less of average levels through early March, setting the stage for an increasingly dangerous fire season. 
Several counties have already been classified as being in an exceptional drought, the most severe category.
Only one of the atmospheric river events to strike Southern California was rated as moderate, which still caused significant issues for burn-scar communities and along the Pacific Coast Highway.
Mudslides were a common sight, as the lack of vegetation allowed water to accumulate and flow freely.
Debris flow on the Pacific Coast Highway.
(Alexandra Datig via Storyful / FOX Weather)
Despite the ending of the wet season, there is a sliver of good news: all of California’s major reservoirs are currently at levels higher than in recent years, with some reaching more than 90% capacity.
Shasta Lake, the state’s largest reservoir, was recently reported to be at approximately 95% capacity, surpassing its historical average by 117%, while Diamond Valley Lake, located southeast of Los Angeles, is at 97% capacity.
Water management officials attribute much of this to a significant snowmelt from the Sierra Nevada, which feeds vital waterways, but with drought conditions intensifying, it’s uncertain how long these levels will remain above historical averages.
According to California water authorities, the Sierra Nevada snowpack – which primarily accumulates during atmospheric river events – contributes roughly 30% of the state’s annual water supply.
California water reservoirs status
(FOX Weather)
Powerful November event tops atmospheric river listThe most powerful atmospheric river this season was linked to a bomb cyclone that rapidly intensified off the West Coast in November. 
The system delivered record-breaking rainfall, mountain snow and hurricane-force winds across much of the West – though Southern California was largely spared.
In Santa Rosa, nearly a foot of rain fell in less than 48 hours, while wind gusts exceeding hurricane strength in the Pacific Northwest caused over half a million power outages. 
Tragically, at least two fatalities were reported near Seattle due to falling trees associated with the storm, and several feet of snow blanketed the mountain region.
The storm system received an “extreme” ranking by Scripps or a 4 out of 5 on its AR scale.
Hundreds of thousands lost power after a bomb cyclone rattled Seattle and other areas in the Northwest. Strong winds knocked trees onto roads and houses and at least 2 people died.…

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Scientists Chart Rapid Recharge Routes for Central Valley Groundwater

scienmag.com
In California’s Central Valley, groundwater depletion has reached a critical point, threatening the stability of communities, agricultural productivity, and delicate ecosystems in one of the most fertile and economically vital regions of the United States. This expansive valley, responsible for producing a substantial portion of the nation’s fruits, vegetables, and nuts, faces the relentless challenge of over-extracting its underground water reserves faster than natural processes can replenish them. However, recent advancements in geophysical imaging provide a promising pathway to address this escalating crisis by identifying where the valley’s land is most suited for recharging its aquifers.

The central dilemma in groundwater recharge strategies is the heterogeneous nature of subsurface sediments across the Central Valley. Beneath the surface lies a dynamic stratigraphy, ranging from porous sands and gravels—remnants of ancient streambeds capable of transmitting water rapidly—to dense clay layers that act as impermeable barriers to infiltration. These clay-rich strata not only prevent water from percolating downward but also cause excess water to linger on the surface, leading to evaporation losses and potential damage to crops sensitive to flooding.

To navigate this intricate underground architecture, the Stanford team utilized electromagnetic (EM) geophysical data collected via a helicopter-mounted sensor array. This system emits inducible magnetic fields, enabling the measurement of electrical conductivity variations up to approximately 300 meters below ground. Since different sediment types conduct electricity differently—clays tend to be conductive while sands and gravels resist electrical flow—this data can be interpreted to produce detailed maps of sediment composition and distribution. By overlapping these geophysical patterns with well log data that record subsurface geology, the researchers developed predictive models tying electrical conductivity profiles to recharge potential.

An innovative product of this research is “fastpath,” a web application designed to aid groundwater managers, farmers, and consultants in pinpointing zones of rapid water infiltration. Fastpath synthesizes EM data and sediment correlations into usable, spatially explicit maps that highlight “flow pathways,” or subsurface conduits where water can swiftly journey from the land surface to underlying aquifers without impediment. These flow paths are critical because thin layers of clay, which may not be easily discernible at larger scales, can drastically alter infiltration dynamics by forcing water to detour or pool.

The research team’s comprehensive analysis indicates that up to 13 million acres of the Central Valley exhibit characteristics favorable for groundwater recharge. Notably, the bulk of this suitable land coincides with active agricultural fields, including orchards, vineyards, and row crops. This overlap suggests an exciting opportunity to integrate groundwater recharge into existing land-use frameworks, leveraging periods of excess surface water—such as during wet seasons—to augment aquifer levels without compromising crop health.

A nuanced aspect of this study is its recognition that recharge suitability is context-dependent. Not all porous terrains are equal in their capacity for recharge; while some areas can allow rapid infiltration minimizing surface ponding, others might facilitate slower water movement, which, although still beneficial, requires careful management to avoid adverse impacts on crops. The fastpath application addresses this variability by offering users multiple metrics, including sand and gravel percentages, exact lengths of subsurface fastpaths, and distances to subsurface clay barriers or the water table. Such granularity provides stakeholders with tailored information essential for optimizing recharge projects, balancing the hydrological benefits while mitigating agricultural risks.

This research responds to a growing urgency in California, where overpumping has not only diminished the volume of recoverable groundwater but also triggered land subsidence—a recession of the ground surface caused by the compaction of drying sediments. Subsidence poses serious threats to infrastructure, reduces aquifer storage capacity, and disrupts ecosystems that depend on stable water tables. By identifying recharge hotspots, the Stanford team’s work offers an invaluable tool to recharge groundwater in a way that can ameliorate these cascading effects.

Importantly, the team’s datasets and analytical tools are publicly accessible via an online platform, fostering transparency and broad utility. Water agencies, researchers, policymakers, and landowners alike can harness these resources to inform strategic planning, design targeted recharge interventions, and ultimately contribute to a more sustainable water management regime in the Central Valley. This open-access approach underlines a commitment to democratizing scientific knowledge and empowering local actors in water stewardship.

The methodological approach combining helicopter-based electromagnetic sensing, well log calibration, and computational modeling marks a significant advancement in hydrogeophysical research. This multi-disciplinary integration enables a spatially comprehensive and finely resolved understanding of subsurface hydrology over one of the largest agricultural regions in the country. Such innovation is emblematic of how geophysical imaging technologies can move beyond academic novelty to practical, high-impact environmental solutions.

Looking ahead, senior author Rosemary Knight and her team plan to expand their work by applying electromagnetic data towards other pressing groundwater challenges. Potential research avenues include identifying optimal sites for active injection of water to reverse ongoing land subsidence and enhancing environmental flows that sustain freshwater ecosystems. These pursuits reinforce a broader vision: transforming voluminous geophysical datasets into actionable strategies that not only mitigate the current groundwater crisis but also foster resilience in the face of climate variability and human pressures.

Integrating such geophysical insights with agricultural practices could redefine land and water management paradigms in dry regions. The ability to identify and manage rapid subsurface flow paths could lead to innovative practices allowing farmers to recharge groundwater without sacrificing crop yields or soil health. This synergy between geoscience and agriculture charts a promising course towards sustainable resource management—an imperative as droughts intensify and water becomes ever more precious.

Ultimately, the Stanford team’s work embodies a pioneering leap in understanding and harnessing the Central Valley’s hidden hydrological potential. By illuminating the complex subterranean landscape through electromagnetic imaging, they have equipped stakeholders with the knowledge to rejuvenate vital water reserves, secure agricultural productivity, and safeguard environmental integrity—underscoring the transformative power of science in addressing one of California’s most urgent challenges.

Subject of Research: Groundwater recharge potential assessment in California’s Central Valley using electromagnetic geophysical imaging.

Article Title: Harnessing the Power of Geophysical Imaging to Recharge California’s Groundwater

Kang, S., Knight, R., et al. “Harnessing the Power of Geophysical Imaging to Recharge California’s Groundwater.” Earth and Space Science, vol. 17, Apr. 2025, DOI:10.1029/2024EA003958.
Knight, R., et al. Prior related work on Central Valley electrical conductivity interpretation. DOI:10.1111/gwat.12656.
Keywords: Groundwater recharge, Central Valley, California, Electromagnetic geophysical imaging, Aquifer sustainability, Subsurface sediments, Agricultural water management, Land subsidence, Hydrogeophysics, Fastpath application, Recharge mapping, Water resource resilience.…

Read the full article at scienmag.com

Salmon fishing shutdown marks a grim milestone. But California shouldn’t give up hope

CalMatters
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Officials warn of ‘urgent invasive species threat’ in Northern California

San Francisco Chronicle
The industrial area along the Port of Stockton, a deepwater shipping channel located on an island in the Sacramento/San Joaquin River Delta, on May 22, 2023, in Stockton, Calif.
George Rose/Getty ImagesLast October, an invasive species never before seen in North America was discovered in the deep waters of the Port of Stockton, about 92 miles east of San Francisco. No larger than the size of a paperclip, the seemingly innocuous, caramel-colored shells of golden mussels clinging to buoys and monitoring equipment in the Sacramento-San Joaquin Delta — and subsequently found at O’Neill Forebay in the San Luis Reservoir near Los Banos — have left California officials scrambling to stop the spread.
On Wednesday, the California Department of Fish and Wildlife released its plan to address what it’s calling an “urgent invasive species threat,” with strategies to prevent further distribution of golden mussels and to minimize their impact on the environment, recreation, agriculture and, notably, drinking water infrastructure. 
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Two-thirds of California residents depend on water from the San Joaquin Delta, as SFGATE previously reported. Krysten Kellum, a spokesperson for the CDFW, said the mollusks are “highly efficient filter feeders that can form dense colonies,” and if they were to spread to the Bay Area, they could clog pipes, impede water flow and damage watercraft motors. 
“These impacts necessitate ongoing, costly removal to maintain operational function,” Kellum said, which can lead to “economic impacts to water conveyances, energy production, recreation, agriculture and ultimately, the public.”
Golden mussels are an invasive species from China and Southeast Asia and were first identified outside of their native range in South America in the 1990s. Experts suspect the mussels were likely introduced to California by a ship traveling from an international port. 
“The discovery of golden mussels in California is a serious challenge that requires coordinated action and a long-term commitment,” CDFW Director Charlton Bonham said in a news release. “This response framework recommends critical steps that must be taken across state, regional and local levels to limit the spread and mitigate the impacts of this invasive species.”
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The agency also plans to offer $1 million in grant funding to boating facility operators to help prevent any new introductions of the species and ensure the long-term ecological health of California’s lakes, reservoirs and other waterways. Reservoir managers are also introducing new guidelines to swimmers and boaters before the busy summer months.
Folsom Lake at the base of the Sierra Foothills and Lake Clementine just outside of Auburn closed to all trailered and motorized vessels on Monday, and people who want to launch their boats there will be required to go through a mandatory 30-day quarantine, per California State Parks. After May 14, visitors will be “required to have a quarantine, and/or decontamination seal intact and verified prior to entering the water,” officials said. Lake Berryessa, similarly, requires hot water decontamination or a 30-day quarantine.
Officials are trying to control the spread of golden mussels in California waterways.
California Department of Fish and WildlifeCurrent rules for other Bay Area waterways are as follows, per a map from KCRA-TV:
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Read the full article at San Francisco Chronicle

A major California city wants to revive its dry river. It’s not easy

San Francisco Chronicle
The Kern River, shown passing near Panorama Park in Bakersfield, is one of the southernmost rivers in the Sierra Nevada. A group of Bakersfield residents is seeking to replenish it as a centerpiece for the community.
Scott Strazzante/S.F. ChronicleFor decades, residents of Bakersfield have lived with a river that’s little more than a channel of dust.
The Kern, which pours from the snowy peaks of the southern Sierra, descends upon California’s ninth-largest city and, in all but the wettest of years, runs dry. A sandy, weed-strewn corridor is left winding unremarkably through the downtown, beside roads, beneath bridges and behind businesses.
“Any major city that has a river or that sort of thing, they try to take advantage of it and make it an asset rather than an eyesore,” said Bill Cooper, who grew up near the Kern and has lived in Bakersfield most of his life. “A river can really add to a community. But nobody wants to live in our crappy town. Unfortunately, Bakersfield has that reputation.”
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A group of residents is trying to change that. Cooper and dozens of others are fighting to bring water back to the Kern River, hoping to create a lush, parklike centerpiece in a city best known for the sunbaked oil fields and farms that surround it.
It isn’t an easy go. The river’s waters are already largely accounted for, some serving the municipal needs of Bakersfield and nearby communities, but most drawn for agriculture, the engine of the regional economy. Keeping more water in the river could mean less for growing almonds, oranges, grapes and more than 200 other crops. Many fear that food supplies, jobs and income stand to be lost, and they’re pushing back.
“To just say ag is using all the water and we need to change that, you’re ignoring decades of history and how this came about,” said Edwin Camp, a third-generation grower outside Bakersfield who has staked his livelihood on the promise of Kern River water. “It scares me. What are we supposed to depend on?” 
The fight over the river is coming to a head this year in the courts. The dispute pits Bakersfield residents, organized under the banner Bring Back the Kern, and a slate of environmental organizations against the water users: the 413,000-person city and a handful of agricultural water districts.
The California Attorney General’s Office also joined the fray recently, intervening on behalf of the residents. The state is concerned that a judgment that fails to restore water to the Kern could open the door to challenges to flow protections on other rivers similarly burdened by overuse and, increasingly, the warming climate.
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Initially, the residents and their allies won a tentative decision that showed promise for their cause. In 2023, after the river unexpectedly swelled during one of the wettest winters in a half-century, a Kern County Superior Court judge issued a preliminary injunction that obligated the city to keep water in the river to safeguard fish, at least until the trial plays out.
But that order was reversed this month by an appeals court. The three-judge panel found that the lower court had not evaluated broader impacts when it made the preliminary decision about the river water, including harm caused to urban and agricultural water supplies, as required by the state Constitution. Attorneys for the city and water districts praised the ruling as a validation of the long-standing interests on the river.
A trial for the case is scheduled for December. Should the proceedings go forward, attorneys for Bring Back the Kern and their partners are expected to argue that draining the river is a violation of California’s public trust doctrine. The doctrine asserts that certain natural resources must be preserved for the public good.
The public trust issue, which is not new to the water world, was perhaps most famously taken up at Mono Lake, where the courts ruled decades ago that the headwaters of the ecologically prized basin couldn’t be entirely siphoned off for thirsty communities in Southern California.
Each public trust case is different, however, and historically, judges have given deference to commerce, including farming. Both environmentalists and water suppliers statewide are watching closely to see how the matter unfolds on the Kern.
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The Mohawk Street bridge goes over the Kern River in Bakersfield, where the river usually runs dry.
Scott Strazzante/S.F. Chronicle
A Bakersfield beachThe Kern River is one of the southernmost rivers in the Sierra Nevada, with headwaters near the base of 14,500-foot Mount Whitney.
The river’s 165-mile course runs unfettered through remote forests and canyons before hitting the dam at Lake Isabella and dropping sharply into the flatlands of the San Joaquin Valley. There, draws on the river provide nearly a third of the surface water that fuels Kern County’s $8 billion of annual crop production — among the most of any California county.
In the past, the waterway continued through Bakersfield to the now dried-up Buena Vista Lake on the valley floor. Since the late 1800s, however, increasing water diversions reduced the flow in its lower reaches. Now there is virtually none.
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“We once had a Bakersfield Beach,” said Rich O’Neil, who grew up in the city in the 1940s and ’50s and remembers year-round flows on the Kern through the downtown. “People would sunbathe, swim, fish. There were places to kayak and canoe.”
In the 1970s, when O’Neil joined fellow Bakersfield resident Bill Cooper to spearhead a bike path along the city’s riverfront, the water had already stopped flowing through town. During the early construction of what would become the Kern River Parkway, with a 30-mile-plus bicycle path, volunteers carried in buckets of water — in lieu of river water — to keep the trees alive.
“We were told by city water people they were trying to get water in the channel,” Cooper said. “We believed them. We were young.”
Since 1976, the city of Bakersfield has owned and operated several diversion dams, or weirs, along the river, each of which steers water into canals. About 25% of the water goes to the city and the rest to agricultural water districts. The districts have either longtime water rights on the Kern or contract with the city for supplies.
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Read the full article at San Francisco Chronicle