Month

June 2021
17
Jun

Bay Fish Still Not Good Eating

After decades of efforts to clean up San Francisco Bay, its fish still carry a toxic load that makes them unfit for human consumption. A new Regional Monitoring Program (RMP) report on its 2019 sport fish survey contains some positive news: an overall decline in polybrominated diphenyl ethers (PBDE), hopeful trends in polychlorinated biphenyls (PCBs) and dioxin, and continued low selenium levels. But no downward trend was found for mercury. Then there are per- and polyfluoroalkyl substances (PFAS), which the RMP only began monitoring in 2009 and for which no human consumption advisory levels have been established in California. These chemicals, used in stainproofing, waterproofing, and many other applications, are a new cause for concern. The 2019 survey was the...
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17
Jun

Trail to a Fire-Safe Watershed

Long insulated from severe risk by mild temperatures and the fog that regularly swaddles the Santa Cruz Mountains, San Mateo County now finds itself — like the rest of the Bay Area — facing the climate-driven prospect of catastrophic wildfire. The threat is leading one of the county’s largest landowners to devote unprecedented resources to fire-prevention efforts in the Peninsula Watershed — efforts that will also restore parts of the landscape to an approximation of their historical condition. “In the last few years, the weather has changed in regards to the relative humidity,” says Fire Safe San Mateo County’s Denise Enea. “Normally you would go up to [the redwood-forested ridgeline at the edge of the watershed] and it would be...
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17
Jun

Thinking Like Beaver to Aid Yellow Creek

Last fall, the Maidu Summit Consortium, a nonprofit composed of nine Mountain Maidu tribal member groups, installed 73 BDAs—beaver dam analogs—in Yellow Creek, a tributary to the North Fork Feather River and a state-listed heritage trout stream. Swift Water Design and U.S. Fish and Wildlife Service designed the structures, and Mountain Maidu tribal youth worked with Swift Water to build them. The idea behind the structures, which mimic beaver dams, is to slow erosion, catch sediment, and build up the river bottom to reverse the incised channel—without importing soil and other materials or emitting carbon from heavy, diesel-powered equipment. “Before this project, PG&E had done some pond and plug projects to restore the meadow,” says Trina Cunningham, executive director of...
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17
Jun

Perspective:

As drought parches California, obliterates its snowpack, and reduces rivers to trickles, a familiar feud over water has resurfaced. Farmers want more of it to irrigate their crops, while fishermen and environmentalists want more left in rivers to protect the state’s Chinook salmon. Mainstream news outlets often portray the struggle as one between two groups ravaged by environmental whims and climate change. However, this interpretation weaves a false equivalence through the narrative. Whereas the state’s Chinook and coho salmon runs have withered to about a tenth of their historic magnitude, California’s agriculture industry has seen steady and soaring growth since its inception 150 years ago. Today, California’s farms occupy millions of acres, use 80 percent of our stored water supply,...
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17
Jun

Moonrise over Giant Marsh: New Monitoring Data from Two-Year-Old Supershore Project

Kathy Boyer is used to getting up in the dark so she can slide across the mudflats into the Bay at first light. But this past May, she got a once-in-a-decade treat. As the professor from SF State’s Estuary & Ocean Science Center aimed her boogie board at some two-year-old eelgrass beds growing off the Richmond shoreline, the Super Flower Blood Moon rose in the blue field of the western sky. “It’s hard to get up at 4 a.m. but if I wasn’t doing this work, I would have missed the eclipse,” said Devon Wallace, a student of Boyer’s and a recent SF State graduate, who was enjoying the chance to get in some field experience after a year grounded...
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17
Jun

Cooking Food in a Sacramento Shipping Channel?

The learned doctors attending the bedside of the Sacramento-San Joaquin River Delta agree on one thing: the patient is not doing well. What ails it, many students of the case suggest, is dehydration: the perennial artificial drought induced by withdrawals of water for human use. Recently, though, attention has turned to a comorbidity: malnutrition. Delta waters simply don’t generate enough basic food, in the form of phytoplankton, to sustain the food chains extending to salmon, sturgeon, and smelt.
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17
Jun

Three Ways to Feed the Marsh

Seal Beach is drowning. As a result of sea-level rise, subsidence, and limited sediment supply, much of the 920-acre National Wildlife Refuge in Orange County can no longer keep its head above water. Pacific cordgrass, normally exposed at low tides, is being completely inundated. Rare nesting habitat for the endangered light-footed clapper rail is disappearing at high tides. It’s a marsh manager’s worst nightmare, and a potential harbinger of things to come later this century for tidal wetlands up and down the state, including those in San Francisco Bay. The problem at Seal Beach has been building for decades, and by 2016 managers knew they had to act—fast. But options for saving the existing marsh were limited. So on an...
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17
Jun

Ballpark Battlegrounds

McKelvey Park’s curious design reveals its double use: a baseball field that is also a flood detention basin designed to protect Mountain View from Permanente Creek's next major 50- to 100-year flood.
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17
Jun

The Coast Whisperer

Sam Schuchat, outgoing chief of the California State Coastal Conservancy, is perhaps one of the most dapper state officials I’ve ever met. He often wears an elegant hat with a brim and band, no Giants bill cap or REI wooly for the leader of a powerful state agency, one that has done more to ensure that the coast is accessible to all Californians than any other. Of course, Schuchat would say he had a lot of help — partners everywhere, lots of folks willing to give any project involving the Conservancy their best. Schuchat is quite the politician: he likes to work the room, shake hands, bend ears, and make deals. I can’t say I know him personally. But I...
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17
Jun

Ancient River Channels Could Speed Groundwater Recharge

By the time California finally began regulating groundwater use in 2014, most of the San Joaquin Valley was in critical overdraft. The Public Policy Institute of California estimates that groundwater pumping in the region has exceeded replenishment by an average of 1.8 million acre-feet per year over the last few decades. This imbalance was even worse during our last drought, when overuse shot up to 2.4 million acre-feet per year. Overpumping puts groundwater aquifers at risk of compaction, permanently reducing their water storage capacity and making surface lands sink. Now, however, San Joaquin Valley groundwater managers must find and implement a fix. The state’s Sustainable Groundwater Management Act mandates balancing the region’s pumping with replenishment by 2040. Managed aquifer recharge...
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17
Jun

Bay Trail Retreat at Bothin Marsh

The Bay Trail connecting Sausalito and Mill Valley is a bustling pathway where recreational bicyclists, bike commuters, and pedestrians all mix amidst the bayfront marsh scenery of the Bothin Marsh Open Space Preserve. Around thirty times per year, though, this scene looks dramatically different, as high tides flood the area with seawater, making the path impassable. Experts say this demonstrates how vulnerable the path and marsh are to sea-level rise, and an ambitious new project is underway to re-engineer the pathway and help the marsh adapt to this future. On June 8, the team working on this “Evolving Shorelines” project announced a final design that moves the Bay Trail to follow the perimeter of the marsh, but the decision didn’t...
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17
Jun

Little Mud, Lotta Work

For decades, patches of Creekside Marsh at Hal Brown Park in Corte Madera lay barren. “There wasn’t a single thing growing,” says Sandy Guldman, 80, a recently retired environmental consultant who is also president of the nonprofit group Friends of Corte Madera Creek Watershed. “The soil was all old fill.” Many of the bare patches are now covered with planted and volunteer pickleweed, saltgrass, marsh baccharis, and more. The remainder is at least partially vegetated, thanks to a recently completed restoration project that was — largely singlehandedly — managed and maintained by Guldman. “[This is an example] of the difference that one person can make,” says Darcie Luce of the San Francisco Estuary Partnership, describing Guldman’s efforts, which included writing...
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07
Jun

New research indicates that survival of juvenile Chinook salmon in the Sacramento River system can be significantly boosted by achieving key thresholds for river flow.

The findings, published in the journal Ecosphere, add important context to the general scientific understanding that more water in the river improves fish survival. Previous studies, the authors explain in their paper, have demonstrated that more juvenile salmon migrating toward the sea complete their journey when the Sacramento River system contains more water. Just how much water has been the source of much controversy among user groups. “These studies have not explored the potential nonlinearities between flow and survival, giving resource managers the difficult task of designing flows intended to help salmon without clear guidance on flow targets,” write the authors, led by Cyril Michel of the Institute of Marine Sciences at UC Santa Cruz. Studying migrating Chinook salmon smolts under a...
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07
Jun

Electrofishing is a powerful but underutilized tool for monitoring Delta fish, particularly species favoring “structured” habitats that are difficult to sample using more common methods like trawls and seines.

By analyzing fish catch data from past surveys, researchers Ryan McKenzie, of the US Fish and Wildlife Service, and Brian Mahardja, of the US Bureau of Reclamation, determined that electrofishing resulted in better detection rates for many native and non-native species than net-based surveys. Although electrofishing is currently restricted to freshwater areas of the Estuary and is more selective of larger fish and those with swim bladders, McKenzie and Mahardja recommend that resource managers employ the technique more widely to support long-term conservation planning. Electrofishing, or e-fishing as it’s sometimes known, uses a generator aboard a small boat to pass electricity through the water beneath and in front of the boat. “When the electricity moves through the water, it can...
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07
Jun

The robust monitoring programs established to track now-rare Delta smelt could benefit other native fishes, too.

Decades ago, resource managers first learned of declining Delta smelt numbers not through surveys targeting the once-abundant native fish, but rather as a byproduct of long-term monitoring programs for non-native striped bass. Now, the authors of a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science advocate for the use of bycatch data from the recently established Enhanced Delta Smelt Monitoring (EDSM) program to better understand juvenile Chinook salmon distribution. “The scope of [this multi-million dollar Delta smelt survey] has not really been seen before in the Estuary,” says lead author Brian Mahardja, a biologist with the US Bureau of Reclamation, “that’s why there was a call to see what else we can gain...
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07
Jun

New insights into Delta smelt swimming behavior could help locate the increasingly elusive fish and prevent losses at the pumps.

Scientists know that smelt use tidal ebbs and flows to migrate landward to spawn, but the degree to which external cues influence behavior remains unclear. In a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science, researchers used computer modeling to predict smelt distribution based on hypothesized swimming behaviors. Six increasingly complex behaviors were tested. For example, the “passive” category assumes that smelt do not swim at all, simply drifting with currents and tides. At the other end of the spectrum, the smelt respond to both turbidity and salinity cues. After assigning a behavior to simulated smelt distributed across the Delta, researchers ran a 133-day simulation of water year 2002, then compared the modeled...
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07
Jun

Water turbidity in the Sacramento-San Joaquin Delta can be used as a reliable indicator of smelt entrainment rates in the fish screens of the export pumps at the southern edge of the Estuary.

In a new study published in the March 2021 issue of San Francisco Estuary and Watershed Science, researchers Lenny Grimaldo, William Smith, and Matthew Nobriga used advanced statistical approaches to understand what factors best predict Delta smelt entrainment at the pumps. The paper builds upon research that Grimaldo conducted in the 2000s, which provided the basis for regulations established in the 2008 Delta smelt Biological Opinion. “This study reinforces previous work that adult Delta smelt salvage is largely explained by hydrodynamics, water clarity (turbidity), precipitation, and sub-adult abundance,” the authors write. Historically, when large numbers of smelt began to appear in the salvage screens of the Delta pumps, pumping would be curtailed. Today, Grimaldo says, the fish are so rare...
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