Category

Pearls

Yet another non-native aquatic species may have made itself at home in the Delta.

As described by US Fish and Wildlife Service fish biologist Brian Mahardja and his co-authors in San Francisco Estuary & Watershed Science, the newcomer is an inch-long, minnow-like fish called the bluefin killifish (Lucania goodei), indigenous to Florida and adjacent southeastern states. It was first detected in the Delta Cross Channel during a beach seine survey in October 2017, and subsequently found in Beaver and Hog sloughs and at Decker, Sherman, and Brannan islands. With surveys curtailed by the coronavirus...
Read More

By looking solely at the results of a single annual fish-counting survey, Californians may be seeing an incomplete reflection of Bay-Delta fish population trends.

A team of scientists analyzed 14 survey programs carried out by state and federal agencies, as well as UC Davis, and concluded that employing such a diverse variety of long-term surveys is essential for accurately tracking and assessing the overall health of San Francisco Estuary’s ecosystem and its resident fishes. The research is described in the June issue of San Francisco Estuary and Watershed Science. Lead author Dylan Stompe, of UC Davis, explains that the research arose from concerns that...
Read More

A unique adaptive behavioral trait that may once have helped winter-run Chinook salmon thrive in the Sacramento River system could now be working against the fish as they face extinction.

The trait – which cues fish when to spawn based on water temperature – isn’t syncing up with current conditions in the Sacramento River below Shasta Dam. A paper published in the June issue of San Francisco Estuary and Watershed Science, reports that cooler springtime river temperatures seem to prompt earlier winter-run spawning while warmer temperatures push back the peak spawning period by a week or two. Under historic conditions, when winter-run Chinook spawned in high-elevation streams now inaccessible to...
Read More

Better scientific preparation could help Delta water and environmental managers respond to droughts more effectively.

That’s one key takeaway from a review of environmental management and the use of science during the 2012-2016 drought commissioned by the Delta Science Program and published in the June 2020 issue of San Francisco Estuary and Watershed Science. “There are lots of mysteries about how to manage water to benefit species, agriculture, upstream and downstream users. I think science is going to be the best solution,” says lead author John Durand of UC Davis’ Center for Watershed Science. Durand...
Read More

Two recent exercises in modeling the hydrological effects of forest thinning and wildfire are yielding intriguing insights.

Hydrogeologist Fadji Maina and colleague Erica Siirila-Woodburn of the Lawrence Berkeley National Laboratory ran simulations of wildfire effects in the Cosumnes River watershed (see map). “We chose the Cosumnes because it’s one of the largest rivers that has no dam in California,” explains Maina. The most significant findings concerned the way wildfire affects groundwater recharge and storage. “It depends on where the wildfire occurs,” says Maina. The underlying rocks—foothill volcanics or High Sierra granites—make a difference. Consistent with earlier studies, the model also...
Read More

A team of scientists is close to chasing down every last thing that happens to nitrogen in wastewater as it passes through the soils and plants of a horizontal levee.

Not only is 97% of the nitrogen removed, but also trace pharmaceuticals. “You just have to focus on where the water is going,” says environmental engineer Aidan Cecchetti, referring to the UC Berkeley-Stanford-ReNUWIt team’s experimentation with three components of flow through the levee system—under the surface, over the surface, or into the air (through evapotranspiration). “In the wastewater pumped to the subsurface, you see full removal of every contaminant except phosphorous.” What’s most astonishing is how much of the work...
Read More

Although the Covid-19 pandemic and attendant economic cataclysm have tripped up some ambitious plans for funding climate resilience in California, other measures to integrate adaptation and planning are still on track.

In July, the Metropolitan Transportation Commission and the Association of Bay Area Governments released the draft of Plan Bay Area 2050, a 30-year plan to guide growth in the nine-county region. “The biggest new integration in the plan is a set of investments to protect our Bay and ocean shorelines from rising sea levels,” says MTC’s Dave Vautin. The plan calls for just under $20 billion in investments ranging from seawalls and traditional levees to horizontal levees and wetland restoration...
Read More

Great whales, the largest creatures in the sea, can help mitigate climate change by locking up carbon in their massive bodies and boosting phytoplankton with their waste products.

A preliminary study by researchers with the International Monetary Fund’s Institute for Capacity Development, the University of Notre Dame, and Duke University found that each great whale sequesters an average of 33 tons of CO2 over its lifetime, taking that carbon out of the atmosphere for centuries: when a whale dies and sinks to the sea floor, it takes that carbon with it, says Joe Roman, conservation biologist and author of Whale. (Compare that to a tree, which sequesters about...
Read More

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....
Read More

Sacramento pikeminnow and introduced striped bass in the middle Sacramento River eat a surprisingly similar diet, says a new study in San Francisco Estuary and Watershed Science.

Both species have been implicated in the decline of vulnerable native species in the river, particularly juvenile Chinook salmon, says lead author Dylan Stompe, a PhD student and researcher at the University of California at Davis. For eight months in 2017, Stompe and fellow researchers with the California State University at Chico and the California Department of Fish and Wildlife surveyed a 35 kilometer reach of the river outside Chico for the two predatory fish. They baited hooks with with...
Read More

Surface water diversions in California’s Central Valley can be estimated based on readily available climate data, say researchers—a boon to efforts to track groundwater use.

Valley groundwater pumping is calculated as the total water demand minus surface water deliveries. However, today’s water model relies on individually reported diversions across the entire valley, and compiling all these data is a slow process; by the time the numbers are crunched, assessments of groundwater use are already outdated. “It can take years,” says Jordan Goodrich of University of Waikato in New Zealand. “It’s one of the biggest problems we face in tracking the Central Valley water budget.” Overdrafting...
Read More

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...
Read More

Beaver dams may offer wildfire protection to western watersheds, in addition to providing better-known benefits such as groundwater recharge, wetland and habitat creation, and riparian restoration.

A new study by California State University Channel Islands professor Emily Fairfax analyzed satellite-derived vegetation indices of riparian areas and beaver dams mapped via Google Earth. At the same time, Fairfax analyzed data for large (over 30,000 acre) wildfires that had occurred between 2000 and 2018 in California, Wyoming, Colorado, Idaho, and Oregon, and compared the fate of beaver-dammed areas to areas without dams. Fairfax found that riparian corridors within 100 meters of beaver ponds were buffered from wildfires. “In...
Read More

Smack in the middle of the unprecedented disruption of normal life brought on by the Covid-19 crisis comes a new report detailing the challenges sea level rise might bring to the Bay region without proactive planning.

 Released on March 26, Adapting to Rising Tides: Bay Area compares the effects of rising waters on communities, natural lands and critical regional systems. “Shoreline flooding from sea level rise and storm events will impact everyone in the Bay Area because the transportation systems we rely on, schools, childcare, and hospitals we depend on, jobs at which we work, and beautiful natural areas we love are at risk, and interconnected across the Bay,” says Dana Brechwald of the Bay Conservation and...
Read More

A new project should dramatically improve conditions for endangered steelhead trout in the lower reaches of Alameda Creek.

The project is part of a long-term effort to restore steelhead to Alameda Creek. Last year, for the first time in decades, the San Francisco Public Utilities Commission began releasing water from a newly retrofitted dam, effectively reviving an important tributary stream. Also in 2019, the Alameda County Flood Control District began construction of a key fish ladder at the BART line crossing that will allow adult steelhead to access the river’s headwaters. The new fish passage enhancement plan focuses...
Read More

A resurgence of dinoflagellates, which can cause harmful algal blooms, may be in the cards for some bays along the U.S. West Coast.

A resurgence of dinoflagellates, which can cause harmful algal blooms, may be in the cards for some bays along the U.S. West Coast. Scientists at UC Santa Cruz have been monitoring phytoplankton weekly at the town’s Municipal Wharf since 2002. In 2018, Alexis Fischer, then a postdoctoral fellow at UC Santa Cruz, augmented these observations with an Imaging FlowCytobot (IFCB) that photographed wharf phytoplankton hourly. She also developed a machine learning classification algorithm to automate identification of the organisms. In...
Read More

New archaeological evidence from the South Bay strengthens the case that Chinook salmon spawned naturally in the Guadalupe River.

Albion Environmental, a Santa Cruz research consulting firm, and researchers from Santa Clara University analyzed thousands of fish bones excavated from a 19th century indigenous village on Mission Creek, a historical Guadalupe River tributary long since buried under modern urban development. In an abstract of their research, which has not yet been published, the authors describe using DNA sequencing on 55 confirmed salmonid bones. They identified 52 as belonging to steelhead trout and three as Chinook salmon. Whether Chinook occurred...
Read More

A grassroots effort to move migrating newts across a Marin County road has drawn to a close, but organizers hope it leads to a more permanent solution.

For roughly half a mile, the two-lane road in a hilly rural area west of Petaluma travels alongside a large, natural body of water called Laguna Lake. On the other side is an oak woodland: the perfect place for California and rough-skinned newts, which spend the dry season in moist terrestrial habitat under leaf litter and wood debris or inside animal burrows. After seeing a number of native newts flattened along the road on rainy winter evenings, a small group...
Read More

The parallels between the Covid-19 pandemic and climate change—threat, shelter, sacrifice, inequity, resource limits, and inaction despite strong science—are striking, and that may be good news.

“We’re seeing profound changes in habits and behaviors, the mobilizing of massive resources and a level of global coordination that we haven’t seen before,” said Otto Scharmer, a social change advocate and lecturer at Massachusetts Institute of Technology in a recent radio interview for PRI’s The World. “This is highly relevant to climate action.” Since nobody is going anywhere, carbon emissions from transportation are down worldwide, giving us a very real glimpse of a greener feature. Some world leaders, meanwhile,...
Read More

Dennis McEwan finished work on the 430-acre Yolo Flyway Farms Tidal Habitat Restoration Project in September 2018. A month later, he retired.

The timing was no accident; he’d delayed his departure from the California Department of Water Resources (DWR) to see the project through after helping to launch it ten years earlier. But even from the very beginning of his career, McEwan had been committed to doing all he could for declining species in and around the Delta. That “calling,” as he put it, began with 25 years at the California Department of Fish and Game (now Fish and Wildlife) supporting Pacific...
Read More
1 2 3 6

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