by Joe Eaton The restoration of the South Bay salt ponds to tidal wetland has, from the very beginning, been an exercise in adaptive management: take an action; monitor the results; make any indicated fixes; repeat. There’s no better example than Pond A8, where the Guadalupe River enters San Francisco Bay via Alviso Slough. Restoration planners were worried that connecting the former salt evaporation pond with the Bay could introduce long-dormant mercury to the wider ecosystem, and initial studies of levels in water bird eggs and fish reinforced that concern. A set of adjustable gates between the pond and the river allows seasonal closure of the pond and the ability to control the flow. But that raised a new question: would the river’s steelhead run get sidetracked into potentially dangerous waters as they move past the gate and out to the Bay? A high-tech approach to tracking the movement of outbound juvenile steelhead has provided preliminary answers, along with better understanding of a little-studied fish population. Meanwhile, continued monitoring of mercury levels suggests opening A8 may not be worsening contamination.
Tagging Steelhead. Photo James Hobbs
Mercury is one of the Bay’s legacy contaminants. As the US Geological Survey’s Laura Valoppi, lead scientist for the restoration project, explains, it’s been washing down from the New Almaden district in the Santa Clara foothills since mining began in 1845:“The more rainfall, the more mercury it mobilizes.” Up to 90 percent of the Guadalupe’s mercury load is mining derived– its watershed once contained one of the largest mercury mines in the Northern Hemisphere. Lester McKee of the San Francisco Estuary Institute’s Clean Water Program calls the river “the number one mercury-pollution hot spot in the Bay Area.” He’s measured higher concentrations of mercury particles in water and sediment, and higher total concentrations in water, in the Guadalupe than any other Bay tributary.
When it reaches the sediments of the former marshland that is now PondA8, mercury can undergo a sinister alchemy called methylation. “Especially in the spring, water temperatures get warm and create good conditions for methylation,” says restoration project manager John Bourgeois. Algae proliferate, then die off, creating a feast for bacteria. The bacteria create methyl mercury, a more toxic form of the element that is much more easily absorbed into aquatic foodwebs, as a byproduct of their metabolism. “If the pond was open to the Bay all year round, flow conditions would cool temperatures down, increase circulation, and minimize the production of algae,” Valoppi continues. But that could expose the Bay to a methylmercury backlog. “We want to restore full tidal action, but not put the Estuary at risk by increasing the input of mercury,” Bourgeois says.
That’s why they built the Notch: a40-foot concrete structure with eight movable gates to let managers govern the movement of water in and out ofA8. The gates are kept closed from December 1 through May 31 every year, out of concern that out-migrating juvenile steelhead might swim into the pond and be unable to navigate back out to the Bay. Managers are also concerned the steelhead might be unable to find refuge from predators in the shallow pond or suffer from adverse water quality.
Moveable gates in the A8 “Notch.” Photo James Hobbs
The seasonal closure also seemed prudent in view of the elevated mercury levels that had been recorded in fish from Guadalupe and Alviso slough sand in the eggs of fish-eating Forster’ sterns that nested locally. Concerns that this could be an ongoing problem were allayed by new data: tern eggs analyzed last year showed a 60 percent decrease in mercury levels from 2011. (Monitoring was interrupted in 2012 for lack of funding.) “Also, in 2013 there was no increase in mercury in fish in the sloughs that we could attribute to A8,”says Valoppi.
Scientists now wonder if the previous increase was a one-off event due to mercury-loaded sediment stirred up by construction activity. “That’s our hope,” says Valoppi. “Even though it was shut six months of the year, there were enough flows that the mercury source decreased. Mercury levels in the terns are still really high, and that’s a concern.” But the pattern suggests this piece of the restoration project is on the right track: “We’re trying to create habitat, not make things worse.”
Netting juvenile steelhead in the upper Guadalupe River watershed. Photo James Hobbs
Mercury researchers encouraged the project to open the Notch earlier or keep it open year round. But what about the steelhead? “We turned it into an experiment,” Bourgeois recalls, underlining the ongoing adaptive management approach of his project. The National Marine Fisheries Service approved a test of alternatives, conditional on a study of steelhead movement. That brought in UC Davis fish biologist Jim Hobbs, who was already monitoring how fish responded to the restoration process. This year, the Notch was opened in March while the steelhead were moving out.
In an urban stream like the Guadalupe, mercury is not the only challenge for steelhead. Fed by creeks in the Santa Cruz Mountains, it flows through downtown San Jose, not far from the Sharks’ arena. A historic coho salmon run is long gone. Steelhead persist, but encounter urban challenges: homeless people turn shopping carts into improvised weirs, trapping adults as they move upstream to spawn. The last thing these anadromous trout need is a death trap at the mouth of the Bay.
Hobbs surveyed the river and its tributaries, selecting five monitoring stations on feeder creeks, along the Guadalupe mainstem, and at the Notch. Steelhead smolts were captured upstream, equipped with passive integrated transponder (PIT) tags — “the same technology used in microchipping pets,” he explains — and released at the capture site. Of 71 tagged fish, only seven were detected by the monitors. “One of the seven went into A8and right back out again,” he adds. Nota huge data set, but Valoppi and Hobbs hope funding will allow a repeat next year — and an extension of mercury monitoring. “As a bonus, we’re getting really good data on a population that’s not well studied,” Bourgeois says. JE
For more great photos of SF Bay fish research click here
Joe Eaton writes about endangered and invasive species, climate and ecosystem science, environmental history, and water issues for ESTUARY. He is also "a semi-obsessive birder" whose pursuit of rarities has taken him to many of California's shores, wetlands, and sewage plants.
Our magazine’s media motto for many years has been “Where there’s an estuary, there’s a crowd.” The San Francisco Estuary is a place where people, wildlife, and commerce congregate, and where watersheds, rivers and the ocean meet and mix, creating a place of unusual diversity. In choosing to tell the...
Ever since the state and federal water projects were built in the 1930s and 1940s, California has captured snowmelt in foothill reservoirs, and moved the fresh water from dam releases and river outflows to parched parts of the state via aqueducts hundreds of miles long. A convoluted system of ancient...
Though the Clean Water Act did an amazing job of reducing wastewater and stormwater pollution of the San Francisco Estuary, some contaminants remain thorny problems. Legacy pollutants like mercury washed into the watershed from upstream gold mining, PCBs from old industrial sites, and selenium from agricultural drainage in the San...
Hothouse Earth
By Ariel Rubissow Okamoto
Photo by Megan Nguyen
Nothing could be stranger than sitting in the dark with thousands of suits and heels, watching a parade of promises to decarbonize from companies and countries large and small, reeling from the beauties of big screen rainforests and indigenous necklaces, and getting all choked up.
It was day two of the September 2018 Global Climate Action Summit in San Francisco when I felt it.
At first I wondered if I was simply starstruck. Most of us labor away trying to fix one small corner of the planet or another without seeing the likes of Harrison Ford, Al Gore, Michael Bloomberg, Van Jones, Jerry Brown – or the ministers or mayors of dozens of cities and countries – in person, on stage and at times angry enough to spit. And between these luminaries a steady stream of CEOs, corporate sustainability officers, and pension fund managers promising percentages of renewables and profits in their portfolios dedicated to the climate cause by 2020-2050.
I tried to give every speaker my full attention: the young man of Vuntut Gwichin heritage from the edge of the Yukon’s Arctic National Wildlife Refuge who pleaded with us not to enter his sacred lands with our drills and dependencies; all the women – swathed in bright patterns and head-scarfs – who kept punching their hearts. “My uncle in Uganda would take 129 years to emit the same amount of carbon as an American would in one year,” said Oxfam’s Winnie Byanyima.
“Our janitors are shutting off the lights you leave on,” said Aida Cardenas, speaking about the frontline workers she trains, mostly immigrants, who are excited to be part of climate change solutions in their new country.
The men on the stage, strutting about in feathers and pinstripes, spoke of hopes and dreams, money and power. “The notion that you can either do good or do well is a myth we have to collectively bust,” said New Jersey Governor Phil Murphy whose state is investing heavily in offshore wind farms.
“Climate change isn’t just about risks, it’s about opportunities,” said Blackrock sustainable investment manager Brian Deese.
But it wasn’t all these fine speeches that started the butterflies. Halfway through the second day of testimonials, it was a slight white-haired woman wrapped in an azure pashmina that pricked my tears. One minute she was on the silver screen with Alec Baldwin and the next she taking a seat on stage. She talked about trees. How trees can solve 30% of our carbon reduction problem. How we have to stop whacking them back in the Amazon and start planting them everywhere else. I couldn’t help thinking of Dr. Seuss and his truffala trees. Jane Goodall, over 80, is as fierce as my Lorax. Or my daughter’s Avatar.
Analyzing my take home feeling from the event I realized it wasn’t the usual fear – killer storms, tidal waves, no food for my kids to eat on a half-baked planet – nor a newfound sense of hope – I’ve always thought nature will get along just fine without us. What I felt was relief. People were actually doing something. Doing a lot. And there was so much more we could do.
As we all pumped fists in the dark, as the presentations went on and on and on because so many people and businesses and countries wanted to STEP UP, I realized how swayed I had let myself be by the doomsday news mill.
“We must be like the river, “ said a boy from Bangladesh named Risalat Khan, who had noticed our Sierra watersheds from the plane. “We must cut through the mountain of obstacles. Let’s be the river!”
Or as Harrison Ford less poetically put it: “Let’s turn off our phones and roll up our sleeves and kick this monster’s ass.”
4th California Climate Change Assessment Blues
by Isaac Pearlman
Since California’s last state-led climate change assessment in 2012, the Golden State has experienced a litany of natural disasters. This includes four years of severe drought from 2012 to 2016, an almost non-existent Sierra Nevada snowpack in 2014-2015 costing $2.1 billion in economic losses, widespread Bay Area flooding from winter 2017 storms, and extremely large and damaging wildfires culminating with this year’s Mendocino Complex fire achieving the dubious distinction of the largest in state history. California’s most recent climate assessment, released August 27th, predicts that for the state and the Bay Area, we can expect even more in the future.
The California state government first began assessing climate impacts formally in 2006, due to an executive order by Governor Schwarzenegger. California’s latest iteration and its fourth overall, includes a dizzying array of 44 technical reports; three topical studies on climate justice, tribal and indigenous communities, and the coast and ocean; as well as nine region-specific analyses.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.
For the first time, California’s latest assessment dives into climate consequences on a regional level. Academics representing nine California regions spearheaded research and summarized the best available science on the variable heat, rain, flooding and extreme event consequences for their areas. For example, the highest local rate of sea level rise in the state is at the rapidly subsiding Humboldt Bay. In San Diego county, the most biodiverse in all of California, preserving its many fragile and endangered species is an urgent priority. Francesca Hopkins from UC Riverside found that the highest rate of childhood asthma in the state isn’t an urban smog-filled city but in the Imperial Valley, where toxic dust from Salton Sea disaster chokes communities – and will only become worse as higher temperatures and less water due to climate change dry and brittle the area.
According to the Bay Area Regional Report, since 1950 the Bay Area has already increased in temperature by 1.7 degrees Fahrenheit and local sea level is eight inches higher than it was one hundred years ago. Future climate will render the Bay Area less suitable for our evergreen redwood and fir forests, and more favorable for tolerant chaparral shrub land. The region’s seven million people and $750 billion economy (almost one-third of California’s total) is predicted to be increasingly beset by more “boom and bust” irregular wet and very dry years, punctuated by increasingly intense and damaging storms.
Unsurprisingly, according to the report the Bay Area’s intensifying housing and equity problems have a multiplier affect with climate change. As Bay Area housing spreads further north, south, and inland the result is higher transportation and energy needs for those with the fewest resources available to afford them; and acute disparity in climate vulnerability across Bay Area communities and populations.
“All Californians will likely endure more illness and be at greater risk of early death because of climate change,” bluntly states the statewide summary brochure for California’s climate assessment. “[However] vulnerable populations that already experience the greatest adverse health impacts will be disproportionately affected.”
“We’re much better at being reactive to a disaster than planning ahead,” said UC Berkeley professor and contributing author David Ackerly at a California Adaptation Forum panel in Sacramento on August 27th. “And it is vulnerable communities that suffer from those disasters. How much human suffering has to happen before it triggers the next round of activity?”
The assessment’s data is publicly available online at “Cal-adapt,” where Californians can explore projected impacts for their neighborhoods, towns, and regions.
The results are alarming for our state’s future: an estimated four to five feet of sea level rise and loss of one to two-thirds of Southern California beaches by 2100, a 50 percent increase in wildfires over 25,000 acres, stronger and longer heat waves, and infrastructure like airports, wastewater treatment plants, rail and roadways increasingly likely to suffer flooding.