In the life of a tidal wetland restoration project, the first levee breach is a major milestone, a kind of graduation. After years of securing funding, navigating the permit process, completing baseline biological surveys, filing endless reports, grading and sculpting the marsh plain, setting out plants—after all that comes the day when the earthen barrier crumbles, the water makes its move, and another marsh can start to regenerate. This fall, that’s happening around the Bay Area as three significant projects—Dutch Slough and Lower Walnut Creek in Contra Costa County and Hill Slough in Solano County—renew long-severed connections between water and land.
The three projects involve two state agencies, a county district, and a nonprofit. Dutch Slough is a California Department of Water Resources project on about 1200 acres of former farmland just south of Jersey Island. Lower Walnut Creek, encompassing Pacheco Marsh, is a joint venture between the Contra Costa County Flood Control District and the John Muir Land Trust, and a novel undertaking for both partners. “Flood Control was traditionally a single-purpose district, but more recently has embraced a watershed stewardship role,” notes senior civil engineer Paul Detjens.
Pacheco Marsh breach, a few days after press time. At the breach event, ESA’s Michelle Orr, one of the design engineers, commented: “This is the missing piece, the donut hole, that connects two large historic marshes.” Video: Robin Meadows
Land Trust executive director Linus Eukel says 232-acre Pacheco Marsh, at present a degraded seasonal wetland, is the trust’s first tidal marsh restoration project. It’s envisioned as a refuge for tidal-marsh wildlife when existing marshes are overtaken by sea-level rise. The Hill Slough site, where eight diked ponds managed by the California Department of Fish and Wildlife (CDFW) as waterfowl habitat will be replaced by 649 acres of tidal marsh, is part of the agency’s Hill Slough Wildlife Area, near Suisun Bay.
An October 29, several hundred people celebrated the breach at Pacheco Marsh. Photo: Ariel R Okamoto
Levee breaches are underway at all three locations: four at Lower Walnut Creek, five at Dutch Slough, thirteen at Hill Slough. Detjens explains what’s involved in a typical breach: “We’ll be using a large excavator positioned at the side of the last remaining bit of soil in the new channel. The operator will skillfully remove scoops of soil and set it aside until the pressure of the tides takes over and water rushes in. Then the operator removes the remaining soil to make that part of the channel the same size as upstream and downstream.”
Sarah Estrella, an environmental scientist with CDFW, says the clustering of breaches reflects regulatory constraints: they have to be completed between September 1 and November 30 to avoid impacts on special-status birds and fish. Tides set further constraints. “We’ll do the breaches at Lower Walnut Creek on a high tide to minimize the release of sediment,” says Detjens.
Dutch Slough project manager Katherine Bandy says the breaches there will happen on a low, incoming tide, at the time when water elevations in the slough balance with water levels within the site. There’s also a turbidity curtain in the slough to minimize the impact of removing the final dirt plug. Supply chain ripple effects complicated the timing of the work at Dutch Slough. Originally, DWR planned to build pedestrian bridges over the breach points before the actual breach, but shortages of construction material forced them to interrupt the bridge-building and complete it after the breach.
Tour of Dutch Slough site in March 2021. Photo Ken James, DWR
Dutch Slough began to change even before the breaches. “As soon as we put water onto the site, wildlife starting showing up,” says Bandy. “They wasted no time getting out there. It started at the tail end of 2019 with our irrigation infrastructure—flood irrigation for the tules, drip irrigation for the trees and shrubs. The flood irrigation attracted shorebirds in crazy numbers in the spring of 2020. As the vegetation filled in, we had birds coming into all the vegetation types.”
Observers have spotted marsh species like Virginia rail and sora, and the secretive American bittern. Northern harriers and other raptors began cruising for prey. Bandy hopes that special-status birds like the California black rail, historically present at the site, and the Ridgway’s rail will put in an appearance. Mammals showed up too: river otters, mink, muskrats, raccoons, coyotes. Even a wandering black bear left its tracks.
As the natural community rebuilds and ecological processes kick in, platoons of researchers will use Dutch Slough as a living laboratory. Some have already done pre-breach baseline surveys; others will watch as things evolve over time. “The US Geological Survey will be out there studying how carbon moves through plants, soils, and water”, Bandy explains. “UC Berkeley researchers will be looking at lateral carbon flux. UC Davis and Cramer Fish Sciences will do fish sampling and aquatic food web studies. It all goes hand in hand with our adaptive management policy—marrying science with land management. The research data will help us learn how to better manage the site.”
Bandy adds that DWR welcomes any researchers who bring their own funding: “There’s a lot of opportunity for whatever people are interested in trying to do with wetland research.”
UC Berkeley scientists are also conducting greenhouse gas studies at Hill Slough. Wildlife being monitored there include western pond turtles, a California species of special concern. “We hadn’t realized how many turtles there were on the site,” says Estrella. The water is too brackish for the exotic red-eared sliders that compete with pond turtles elsewhere. The reptiles are trapped in hoop nets and outfitted with radio transmitters, glued to their shells.
Salt marsh harvest mice are also being studied at the site. Estrella says the restored marsh at Hill Slough will provide habitat connectivity for the mouse, the Ridgway’s and California black rails, and two special-status plants, the Suisun thistle and soft bird’s-beak. Pacheco Marsh is also salt marsh harvest mouse and black rail habitat; Ridgway’s rail is hoped for but not yet confirmed. According to Detjens, Lower Walnut Creek, while not optimal for spawning salmonids, is potentially good rearing habitat for Chinook salmon smolts on their outward migration.
Biomonitor Nita Superak flags the native Suisun Marsh aster, a rarish plant that occurs on the outer tidal levees at Hill Slough. Photo: Sarah Estrella, CDFW
Hill Slough will be open to the public for fishing, birding, and wildlife observation, but, unlike the nearby Grizzly Island Wildlife Area, not for hunting. A two-mile loop trail, connected to Suisun City’s Grizzly Island Trail, is already in place. Public access is central to the John Muir Land Trust’s plans for Pacheco Marsh, with trails, blinds for birding, and kayak launches. “It will be a wonderful site for birders,” says Eukel. There will also be an environmental education center, still in the design phase: “There are disadvantaged communities nearby, kids who live in Bay Point who have never been to the Bay. This will help them understand how salt marshes are vital.”
Public access at Dutch Slough is farther off: “We’re just getting to the phase where we can focus on developing trails and be ready to bring people out,” Bandy says. That may happen within the next couple of years. DWR is partnering with the city of Oakley to link a 55-acre city park to the wetlands, and the East Bay Regional Park District plans to extend the Marsh Trail to Dutch Slough.
Estrella has invested nine years at Hill Slough. Her reaction to the project’s completion: “It’s a big relief.” Detjens has led the Lower Walnut Creek project for 18 years. Bandy, who took over as project manager after Patricia Finfrock retired, says she’s a relative newcomer to Dutch Slough. “Some people have been working on it for 20 years,” she reflects. “Being here at this moment when you’re watching it come to life, seeing the animals responding immediately, is so satisfying. It’s amazing to be part of it, seeing it happen for real.”
Top Photo: Hill Slough breach. Courtesy Sarah Estrella, CDFW
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.