More than half the water diverted from Central Valley rivers is used to irrigate cattle-feed crops, implicating beef and dairy as top drivers of recent fish declines.

Delta Landscapes & Waterways



05
Aug

More than half the water diverted from Central Valley rivers is used to irrigate cattle-feed crops, implicating beef and dairy as top drivers of recent fish declines.

Recent findings, published in Nature Sustainability in March, strengthen the environmental arguments for going vegan while rewriting the familiar narrative that almonds and other high-value tree crops are the top hogs of Central Valley water resources. The study’s authors, led by Brian Richter of Virginia-based Sustainable Waters, focused on the arid West and found that irrigated crops like alfalfa and hay, more than any others, are drying out rivers. The reduced flows are pushing dozens of fish species toward extinction. “We estimate that 60 fish species in the western US are at elevated risk of imperilment or extinction due to flow depletion, and that 53 (88%) of these are primarily due to irrigation of cattle-feed crops,” the scientists wrote in...
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06
Jul

Should the striped bass be a suspect in the decline of the Delta smelt?

Writing in the March issue of San Francisco Estuary and Watershed Science, US Fish and Wildlife Service biologists Matt Nobriga and Will Smith suggest that the smelt’s baseline might have shifted long before anyone was paying attention, and striped bass predation may have constrained its numbers before recent water diversions and food web changes added their effects. The smelt’s historic abundance is unknown; systematic surveys didn’t begin until 1959. But it’s thought to have evolved its boom-and-bust life history in response to predation pressure from native fish or birds. Was the bass, introduced in the late 19th century, one predator too many, or too effective? Nobriga notes that Delta smelt don’t respond predictably to changing flows: “From what we know...
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18
Jun

Sinking Islands Capture Carbon Credits

By Emily Underwood As sea levels rise and land in the Delta sinks, agencies and landowners are recognizing that levees alone will not protect critical fresh water supplies and infrastructure. Encouraged by a recently vetted new method for calculating carbon offsets from wetlands, a flurry of new climate adaptation projects on publicly owned islands strewn along the central Delta corridor aim to defend against sea-level rise, restore habitat, and reduce greenhouse gas emissions. Until recently, the prospect of selling carbon credits in the Delta remained fairly abstract. This spring, however, researchers from DWR, UC Davis, UC Berkeley, and the consulting company HydroFocus cleared an important hurdle when an independent team of scientists approved their protocol for determining how many tons...
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18
Jun

Carbon Goes Deep

By Aleta George Many Yolo County farmers and ranchers are keenly aware of climate shifts and actively involved in GHG reduction strategies. Scott and Karen Stone run Yolo Land & Cattle, a 7,500-acre ranch that lies partly in the Blue Ridge Berryessa Natural Area. The Stones have planted riparian areas and hedgerows for carbon sequestration, use solar water pumps to reduce GHGs, and manage a 400-acre conservation easement for Swainson’s hawk on their irrigated pastureland. In the Capay Valley, Fully Belly Farm is participating with several other California farmers in a study of an organic, no-till vegetable production system to capture and retain the most possible carbon in the soil, reduce greenhouse gas emissions, and produce healthier soils and more...
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Kinky Fish Spines Linked to Selenium

Scientists with the U.S. Geological Survey and the National Oceanic and Atmospheric Administration are using new tools to track selenium, with the Sacramento splittail, a California-endemic fish, as an indicator species. In some sampled splittail, selenium levels exceeded the proposed EPA protective criteria for fish ovaries.
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05
Mar

Bob Fujimura spent his entire career with the California Department of Fish and Wildlife.

Bob Fujimura spent his entire career with the California Department of Fish and Wildlife. From 1987 until his retirement in late 2018, Fujimura served in a variety of roles at the department—but he is likely best known for heading up its long-term monitoring of native fishes in the Bay and Delta. Beginning in the mid-2000s, he oversaw annual smelt surveys with far-reaching implications for management and conservation, including the Spring Kodiak Trawl, which determines the relative abundance and distribution of spawning Delta smelt; the Smelt Larva Survey, which provides near real-time distribution data for longfin smelt larvae; and the 20mm Survey, which tracks post-larval juvenile Delta smelt throughout their historical spring range. “My goal was to provide good science throughout...
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05
Mar

Rainer Hoenicke is optimistic about the changes he saw in his five years as the Delta Stewardship Council’s Science Director.

“People are coming to the table and realizing we need to be anticipating and forecasting how to adapt,” he says. Prior to joining the Science Program, Hoenicke served for nearly a decade as deputy and executive director of the San Francisco Estuary Institute, where he managed two Boards of Directors and reorganized the Institute’s program areas. “I felt challenged to do something different,” he says of the move, “since the Delta is much more controversial territory.” In Hoenicke’s eyes, the capstone to his career came in October 2018. The U.S. Bureau of Reclamation increased its science allocation for California, and it and the Council were able to use pre-existing proposal submittal and evaluation infrastructure developed by the California Department of...
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22
Jan

A new system for treating agricultural drainage water in the Delta could also help rebuild subsided islands.

The approach—known as a Chemically Enhanced Treatment Wetland—combines chemical treatment with natural wetland processes; researchers tested it on Twitchell Island, which features corn and rice crops, as well as wetlands. They dosed agricultural ditch water with dissolved organic material (DOM), then treated it with a coagulant to precipitate the DOM, forming flocculant. The resulting water then passed though treatment wetlands, where the flocculant settled and blended with plant detritus in the sediment. The study, reported in the September 2019 San Francisco Estuary and Watershed Science, found that the combined system removed drinking water contaminants including dissolved organic carbon, disinfection byproduct precursors, and methylmercury. Another possible benefit is subsidence reversal: the researchers found that sediment and carbon accreted about four times...
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22
Jan

Manmade features in the Delta, including riprap-armored banks, water diversion pipes, pilings, and woody debris, may be sending juvenile native fishes into the jaws of finned invaders.

“We know from a decade of doing survival studies that migrating juvenile salmon are dropping out of the system pretty much everywhere in the Delta,” says UC Santa Cruz fisheries biologist Brendan Lehman. “Physical habitat features are potentially aggregating predators and prey in ways detrimental to salmon smolts and steelhead.” The scientists report in the December 2019 San Francisco Estuary and Watershed Science that artificial light and submerged aquatic vegetation pose the most severe and widespread risks to native fishes. Plants like Brazilian waterweed form dense underwater mats across vast reaches of the Delta. These mats have nurtured a rise in predatory bass populations and force prey fish into exposed channel centers. The artificial lighting pervasive along docks and buildings...
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22
Jan

While the acreage of wetland restoration projects is growing throughout the Delta, scientists are still working to understand how best to help these areas become fully functioning, complex habitat as quickly and successfully as possible.

A study published in September’s San Francisco Estuary and Watershed Science shed light on some essential questions about what triggers seed generation in wetland habitat. “Wetland restoration practices can be enhanced by a solid understanding of basic plant life history and species ecology,” says co-author Taylor Sloey of Yale-NUS College in Singapore. The researchers looked at three questions: what seeds are present in the seed bank (the viable seeds that accumulate naturally in the soil), and how exposure to cold and flood affects their germination. The study was based on seed bank samples taken from wetlands on the Delta’s Liberty Island. Though the island was drained and farmed throughout most of the 20th century, it has been naturally recolonized by...
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22
Jan

An emergency barrier installed to protect the state’s water supply from saltwater intrusion during the recent record-setting drought had little effect on the ecosystem.

In spring 2015 the California Department of Water Resources dropped 150,000 tons of rock into False River in the Central Delta to halt encroaching tides that had little freshwater to hold them back. A few months later, it was clear the barrier worked, as salinity rose on one side and fell on the other. But what were the effects on local plants and animals? Through six overlapping yet distinct projects funded by the state Delta Science Program and NASA, and described in the September 2019 issue of San Francisco Estuary and Watershed Science, researchers studied impacts on water quality and movement, zooplankton and phytoplankton, submerged aquatic vegetation, nutrients, and two species of clam. What they found, says Wim Kimmerer of...
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05
Dec

Flows and Ecosystem Function Dominate Delta Plan Amendment

With the Delta lagging behind the Bay on four of the State of the Estuary Report’s five indicators, the last long-range plan for restoring its ecological health abandoned, and the threats from climate change becoming ever more alarming, the need for a new regulatory vision for the region may never have been greater. A pending amendment to the Delta Plan, shared by Ron Melcer at the State of the Estuary Conference as part of a policy update session, is meant to provide that vision and the strategies to achieve it. The amendment — to Chapter Four of the Delta Plan, which focuses on the Delta ecosystem — was developed in response to the state’s pivot away from the 2013 Bay-Delta...
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19
Sep

Drones Pilot Vegetation Mapping

By Michael Hunter Adamson In the world of conservation, as attested to by multiple speakers at a late summer UC Davis event, drones, or UAVs (unmanned aerial vehicles) may be the vehicle of choice for mapping the future of invasive plant management in the Delta. The California Department of Water Resources began using UAVs in earnest after the Oroville dam failure in the winter of 2017, when drones offered visuals no one could get near on the ground. The Blacklock Ranch, a leveed island in Suisun Marsh, offers a more current example of how drones are now being employed at restoration sites. “We are using our UAVs and multispectral [red, blue, green, and infrared spectrums, for example] capabilities to map...
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Wildlife and Way of Life in the North Delta?

There may not be a way to give everyone what they want from the Delta. But there are ways to restore ecosystems while preserving local communities. This is true even along State Route 160, which traverses the most populated and most intensively farmed part of the region. The highway follows the Sacramento River into the Delta, twisting and turning around leveed islands between Freeport and Rio Vista. This is the North Delta and it's a spectacular drive...
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13
May

Joaquin Esquivel is impatient with the narrative that has dominated California water policy for decades, especially when it comes to the Delta and the eternal tug-of-war between farms, cities and the environment.

“For so long in the water space you’ve had these false dichotomies where you are being told you have to choose one or the other,” says Esquivel, who Governor Gavin Newsom appointed Chair of the State Water Resources Control Board in February. “These narratives can fuel themselves, they take root in communities, but they don’t really do much to get to the heart of the policy question.” A native of the Coachella Valley, Esquivel served on the State Board for two years prior to his appointment. He cites literature as a particular passion, and had planned on a career in academia before a college internship in former Senator Barbara Boxer’s Washington, D.C. office turned into a full-time job. “What I...
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13
May

Susan Tatayon wants to bridge the emerging communication gap between Delta science and policy.

While Tatayon, who was installed as Chair of the Delta Stewardship Council in January, sees good communication efforts on the part of council scientists and staff, not everyone on the receiving end gets their drift. “What I’m learning from some council members and others is that they don’t understand the connection between the science being done and the policies they want to make.” Tatayon assumes her new position after a career that includes stints at The Nature Conservancy, the U.S. Bureau of Reclamation and the Department of Water Resources. It was at DWR as a young staffer in the Department of Planning that Tatayon discovered her interest in environmental protection: “I was assigned to read impassioned letters about saving Mono...
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06
May

Louise Conrad sees the Delta Stewardship Council’s science program, which she now leads, as poised to shift into a new gear – from breaking down the science landscape and building a new foundation for Delta science to actually doing it.

 “With the update of the Delta science plan done, we can now can sink our teeth into some topical issues our scientists can be passionate about, such as aquatic invasive vegetation, microcystis and climate change, for example,” says the former Department of Water Resources (DWR) fish biologist. Conrad grew up in Philadelphia and developed an interest in conservation on summer road trips to western national parks in their family’s Dodge Ram. “My mom sewed us individual seat covers with pockets for entertainment items,” she says.  She is pleased to be part of an agency with so many women in leadership positions and with such a broad mandate. At DWR, she says, legal mandates required them to focus on water project...
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13
Feb

Haggles over the what, where, and when of Delta conservation got a reset this January with the state’s release of a new collaborative framework focused on opportunities, not species.

The California Department of Fish & Wildlife’s new Delta Conservation Framework tries to fill the vision vacuum left by former Governor Brown’s early pivot away from the 2013 Bay-Delta Conservation Plan, a plan that touched in some shape or way on 160,000 acres of the Delta. “It was too big and too unwieldy for people to manage, and there were too many questions about its effects, and how it would be implemented – particularly as it related to the Delta as a unique place,” says the agency’s Carl Wilcox. In 2016, with the help of the Delta Conservancy, CDFW held a series of workshops with landowners, agencies, biologists and others to define new conservation goals and strategies in light of...
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13
Dec

Sleuthing Sturgeon Snags

Local green sturgeon are struggling. The population that spawns in the Sacramento –San Joaquin River Delta was declared federally threatened in 2006. Researchers at UC Davis, which hosts the world’s only green sturgeon rearing program, are now trying to figure out why the fish is in trouble. “If we knew how large they are when they’re moving through each portion of the system, we’d know a lot more about the threats they face at each life state, and where we need to put our energy,” says postdoctoral fellow Anna Steel.
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13
Nov

The Nature Conservancy’s venture in growing food crops for wintering cranes on Staten Island is under fire from an unexpected source—the Wetlands Preservation Foundation.

The nonprofit, headed by Stockton tomato packer Dino Cortopassi, is suing TNC and the California Department of Water Resources, which holds a conservation easement on Staten Island, alleging farming practices that cause soil subsidence and threaten levee integrity, and misuse of revenue from farm operations. The 9200-acre farm, acquired by TNC in 2001, is a major destination for migratory greater and lesser sandhill cranes (the latter a California endangered species) as well as Aleutian cackling geese and other birds. As habitat is replaced by houses, orchards, and vineyards, a third of the state’s crane population converges on the island to feed in corn and triticale fields and roost at night. While corn cultivation is recognized as depleting the Delta’s peat...
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