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Pearls

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...
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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....
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Levels of pyrethroid insecticides spike sharply in the North Delta’s Cache Slough during winter rainstorms, rendering the water so toxic that it decimates laboratory populations of a half-inch crustacean called Hyalella azteca.

However, according to a study reported in the September 2019 San Francisco Estuary and Watershed Science, Hyalella collected in the wild from Cache Slough are resistant to pyrethroids. Genetic analysis revealed that, collectively, Hyalella in the slough have four mutations for pyrethroid resistance. They also have a fifth mutation for resistance to organophosphates and likely carbamates, two additional major classes of pesticides that are applied extensively on agricultural and urban lands. “Hyalella are special,” explains co-author Helen Poynton, a molecular...
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Researchers hope new computer models will help clarify the effects of entrainment on the population of endangered Delta smelt.

Entrainment at the South Delta pumps of the State Water Project and the Central Valley Project has been a concern for years, but disentangling its impact on the dwindling smelt population from those of other environmental and water management factors isn’t easy, and operational differences between the SWP and CVP facilities complicate analysis. Now, US Fish and Wildlife Service statistician Will Smith has developed computer models for entrainment effects on different smelt life stages, part of a larger Delta Smelt...
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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...
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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...
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A recent test found more than 250 chemicals in the Delta’s Cache Slough, but “Dr Doom” says figuring out what they all are, and their concentrations, is beside the point in our efforts to understand stressors on native fish resilience.

“Knowing the effect on the fish is more informative than knowing which chemicals may be causing it,” says UC Davis’ Richard Connon (whose colleagues gave him his sinister title), referring to taking an ecological rather than regulatory perspective on fish health, and also to the less obvious sublethal effects of contaminants on fish behavior and reproduction. Connon is the lead author of a wide-ranging journal article in the December 2019 issue of SFEWS on how to better focus contaminants research...
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California Sun Podcast Interview with ESTUARY’s Editor Dives into All Things Bay & Delta on the Front Burner Today

This August the California Sun’s Jeff Schechtman interviewed ESTUARY magazine’s editor in chief Ariel Rubissow Okamoto, also a long-time Bay Area science writer, about her personal opinions on the resiliency of the largest estuary on the West Coast, the challenges facing the Sacramento–San Joaquin Delta, and the potential impacts of climate change and sea level rise on the San Francisco Bay.  Listen to the 20-minute podcast here. Mentions: Nutrients, Toxics, Giant Marsh, Adaptation Atlas, Resilience, Sea Level Rise impacts, BCDC...
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Two long-scarce freshwater mammal species are staging a comeback in Bay Area waterways.

The California Department of Fish and Wildlife (CDFW) recently updated its distribution map for the state’s river otters, reflecting sightings by citizen-scientist “otter-spotters.” River Otter Ecology Project director Megan Isadore says the map fills in major gaps in the North Bay and East Bay, increasing otters’ documented range by 4,100 square miles. “It’s interesting to find how well they’re doing in very populated cities,” she says. Absent from the Bay Area for decades, river otters were observed near Tomales in...
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A small but mighty wetlands project on the San Rafael waterfront is moving forward thanks to a $1 million planning and design grant from the San Francisco Bay Restoration Authority.

Restoration of the heavily eroded 20-acre Tiscornia Marsh at the mouth of the San Rafael Canal will use dredged sediment to create new habitat for the endangered Ridgeway’s rail and salt marsh harvest mouse, migratory shorebirds, and other marsh species. Meanwhile, improvement of an adjacent levee will enhance public access along a levee-top section of the Bay Trail and, perhaps most critically, provide flood protection for the nearby Canal District, a dense, low-income community that’s home to many Latino immigrants...
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Sea level rise combined with future coastal storms will be costlier and more destructive to California than earthquakes or wildfires.

A new study by United States Geological Survey researchers examines how future coastal storms and waves will affect California’s shoreline via erosion and flooding in conjunction with sea-level rise. And it puts numbers on the cost and people affected by California’s future storms and waves: about $150 billion in property and 600,000 people by 2100. “Bay Area communities account for two-thirds of the projected impacts across the state over the next century,” explains lead author Patrick Barnard. “Many communities, such...
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Coyote Valley, an important wildlife corridor connecting the Santa Cruz and Diablo Mountain ranges, would receive new protections under state legislation introduced in April.

AB 948 would create a new Coyote Valley Conservation Program, to be administered by the Santa Clara Open Space Authority. The bill would expand the existing protected area from 7,400 acres to 17,000 acres, and boost new efforts to preserve its resources. Coyote Valley, which drains the ecologically rich upper watershed of Coyote Creek, has long faced development threats as surrounding South Bay communities expand. The area provides critical habitat for critters large and small, which use the valley—especially its...
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Invasive clams and freshwater exports from the Delta have created dramatic and unsustainable changes in the San Francisco Estuary’s foodweb over the past 50 years.

 A study by UC Davis researchers found a 97% decline in phytoplankton, the microscopic foundation of the food chain. “Understanding the causes for the decline in the pelagic [water column] community is essential so that efficient solutions can be implemented,” says Bruce Hammock, a research scientist at the UC Davis School of Veterinary Medicine’s Aquatic Health Program. The invasive clams (Potamocorbula amurensis), originally from Asia, have been over-consuming phytoplankton and zooplankton for more than 30 years, and have long been...
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New shoreline strategies piloted in Puget Sound could help young fish in urbanized estuaries elsewhere.

When Seattle rebuilt its seawall in 2017, they hoped to make the hardened shoreline a little less daunting for the young salmon that hug it closely on their journey to the ocean. Project managers took a three-pronged approach. First, they added texture and complexity into the new concrete seawall to encourage invertebrates, food for the young fish, to settle in nooks and crannies and on horizontal “shelves” built into the wall. Mussels, ecosystem engineers, have settled on the shelves and...
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While it’s been a tough year for marine mammals along the California coast, local San Francisco Bay conditions may have afforded scientists a unique opportunity to study emerging ocean problems.

The Marine Mammal Center participated in 12 necropsies of deceased gray whales in and around the Bay. Later in the year, malnourished Guadalupe fur seals stranded along the coast at a historically high rate. In June, a surprisingly early toxic algae bloom off the coast of San Luis Obispo caused a rash of cases of Domoic Acid Toxicity among pregnant and yearling California sea lions. Dr. Cara Field, staff veterinarian at The Marine Mammal Center, has some theories as to...
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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...
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Jessica Fain got a crash course in resilience planning when Hurricane Sandy hit the East Coast in 2012.

Fain, Planning Director for the Bay Conservation and Development Commission (BCDC) since October, was part of a three-person office in the Waterfront and Open Space Division of New York’s Department of City Planning. “We were doing a small study on adaptation options,” she recalls. “In the middle of that, Sandy hit. Suddenly all eyes were on us.” Fain brings that background to a setting unlike New York in many ways. Instead of five boroughs, for example, she’s dealing with a...
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Therese McMillan inherits huge challenges as the new Executive Director of the Metropolitan Transportation Commission.

The Bay Area region is beleaguered by traffic, a crippling housing shortage, and growing inequality. MTC plays a role in all these areas. “We have a master coordinator role in being able to knit the region together through land use and transportation planning, and major dollar investments,” says McMillan of the MTC, which distributes billions of public transportation dollars collected annually by local, state and federal governments, although she notes that the agency doesn’t “have land use authority, or our...
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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....
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Kris Tjernell thinks there could hardly be more a more exciting time to be leading conservation and water management programs in the country’s most populous and perhaps most water-stressed state.

“I see opportunities for big change,” says Tjernell, who was appointed California Department of Water Resources’ deputy director last May. At the time the DWR was adopting a new approach toward land and water management—especially the inclusion of floodplain restoration in many of its flood control projects. “We are demanding a lot out of the landscape of the Delta, and we are demanding a lot out of the Central Valley and beyond,” Tjernell says, describing a system of resource allocation...
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About Us

The San Francisco Bay-Delta is named in the federal Clean Water Act as one of 28 “estuaries of national significance." For over 20 years, the San Francisco Estuary Partnership has worked together with local communities and federal and state agencies to improve the health of California’s most urbanized estuary.

San Francisco Estuary Partnership 1515 Clay Street, Suite 1400 Oakland, CA 94612 (510) 622-2304

Association of Bay Area Governments