A typically foggy and cold “June gloom” morning gave way to a blindingly bright sunny afternoon at the Tijuana Estuary as Mike McCoy and I walked down a path bordered by bright yellow goldenbush. The air smelled of sweet nectar, common sagebrush and coastal sage scrub, mixed with prickly pear cactus and black mustard, an invasive weed that can top 6 feet, as tall as McCoy, or taller.
At my feet, a metal plaque on a rock read “McCoy Trail”; our path, I realized, was named after my companion, a local veterinarian in his early 80s with an easy, toothy smile and a penchant for hippie T-shirts sporting pictures of wolves.
McCoy and I followed the path until it opened onto a wide vista. To our right, about a quarter-mile away, stood houses and sleek palm trees — the edge of the city of Imperial Beach, California — and to the left lay an airstrip, part of a U.S. Navy facility. But straight ahead, through brush and marsh grasses, we could glimpse the shallow Tijuana River, meandering about a mile through its delta and widening as it reached the Pacific.
Estuaries are coastal water bodies, partially protected by a barrier island or peninsula, where freshwater and saltwater mix. They rank among the world’s most productive and dynamic ecosystems: Despite rising sea levels and river flooding caused by climate change, which can drown or otherwise destroy estuarine habitats, the Tijuana River National Estuarine Research Reserve is one of Southern California’s most intact salt marsh ecosystems. Its 2,800 acres serve as a home or stopover for more than 370 species of migratory and native birds, including endangered ones like the western snowy plover and the light-footed Ridgway’s rail, whose decline was driven by salt marsh loss. McCoy first became enamored with this place more than 50 years ago, largely because of birds like these.
Estuaries rank among the world’s most productive and dynamic ecosystems: Despite rising sea levels and river flooding caused by climate change.
But what’s especially unique about this estuary is the fact that it’s still here. It’s survived centuries of nearby development: To the east and north, it’s surrounded by Imperial Beach, population about 26,000, about half of whom are Latino. Imperial Beach isn’t your typical Southern California coastal community filled with multimillion-dollar homes; the median household income is less than $70,000. Tijuana, Mexico, is less than 10 miles south. The two cities are divided by the beefed-up border wall but linked by the Tijuana River and infrastructure, including a wastewater facility on the U.S. side that treats sewage from Mexico.
After about 20 minutes, McCoy and I turned around and ran into a man in sweatpants and a baseball cap who called out, “How’s it going, Doc?” People all over town recognize McCoy for his longtime veterinary practice, for bicycling around town — and, together with his wife, Patricia, for waging the radical fight to protect this estuary.
Decades ago, realizing that the Tijuana Estuary was at risk of destruction, the McCoys mobilized friends and neighbors across Imperial Beach, riding the wave of the 1960s and ’70s U.S. environmental movement. Then they passed the torch to the following generations even as the struggle — for open space, for conservation and against climate change — grew more layered and complex.
“I guess we went on (defending the estuary) because it’s emotional,” Mike McCoy told me, struggling to find the words to explain why he and Patricia stuck to this place. “That fight continued for 10 damn years.”
Today, less than 15% of Washington, Oregon and California’s estuarine habitat survives along the coast. Most of it has been destroyed or fractured by human infrastructure, from freeways and power lines to railroads, and what little remains faces new threats posed by the climate crisis. This makes the Tijuana Estuary a symbol of what once was here, and could be again, if coastal cities and counties focus on restoration and adaptation instead of urban growth, and recognize the importance — and fragility — of these ecosystems.
THE KUMEYAAY PEOPLE lived here or relied on the Tijuana Estuary for thousands of years; some of the 12 Kumeyaay bands that exist today continue to do so. The arrival of the Spanish in the 16th century brought disease, Catholic missionaries, and rancherías with cattle and horses. By the mid-20th century, even more drastic changes had occurred. Farming took over part of the Tijuana River Valley on the U.S. side; across the border, in Tijuana, the population grew more rapidly than the city’s infrastructure could handle. Rail lines, freeways, airports sprang up.
What’s especially unique about this estuary is the fact that it’s still here. It’s survived centuries of nearby development.
Meanwhile, Mike McCoy was growing up in Boulder, Colorado. His father, a building contractor, took the boy to his job sites. When McCoy was 6, they went to a marsh north of town where a crew planned to connect a reservoir to a city water line. In McCoy’s memory, cattails rustled by the water and red-winged blackbirds filled the spring day. But then the heavy equipment came down and “mud went everywhere, and the marsh went quiet,” he recalled during a 2023 lecture. Witnessing the destruction left a huge impression: “I still feel it today.”
The McCoys’ fight for the Tijuana Estuary started in 1971, after they moved to Imperial Beach. Developers had proposed dredging the estuary and transforming it into a concrete channel to prevent flooding since the 1950s. There was also talk of building an upscale marina. Influenced by the research of biologists Joy Zedler and Paul Jorgensen, experts on wetlands and restoration ecology, the McCoys set out to stop the development.
“Rachel Carson’s Silent Spring started the ball rolling,” Mike McCoy told me, referring to the landmark 1962 book that documented the destruction caused by pesticides, dramatically shifting public opinion about environmental issues in the U.S. The Environmental Protection Agency was established in 1970, and in 1973, the Endangered Species Act passed. It was a time of both hope and urgency.
By the spring of 1974, the San Diego-based Helix Land Company owned the estuary land. Imperial Beach and San Diego County, eager to issue building permits, laid out three options: Construct a concrete channel from Mexico to the Pacific, paving the way for the development of the entire valley; develop only part of the estuary; or leave it as it was.
Patricia McCoy, a longtime civic activist, pulled together a political coalition that included friends, locals, property owners, environmentalists, and even the people who brought their pets to the veterinary practice. Mike McCoy traveled to Washington, D.C., to meet with Richard Nixon’s undersecretary of the Interior, Nathaniel P. Reed, proposing that the U.S. Fish and Wildlife Service turn the estuary into a national wildlife refuge. Reed and others put him off, telling him to start with local officials. So he did.
“I think that we were tenacious,” Patricia McCoy said when I visited her recently at the couple’s modest Imperial Beach home, less than a mile from the estuary. Now in her late 80s, Patricia has a heart condition that keeps her from getting around, but she’s as charming and self-deprecating as she was decades ago. “We were the movers and shakers,” she told me. This was a time when you could write a letter or pick up the phone and “actually talk to a congressman, even though you were nobody in particular,” she said. There were people in Imperial Beach who disagreed with them, she added, but they still brought their animals to her husband.
The Environmental Protection Agency was established in 1970, and in 1973, the Endangered Species Act passed. It was a time of both hope and urgency.
The battle over the estuary dragged on for years. By the mid ’70s, the Helix Land Company had decided to build a $200 million residential marina for up to 7,000 people. Local and county officials eagerly supported the commercial development of the entire waterfront.
But then nature got in the way. In January 1980, a king tide, an exceptionally high tide that usually occurs once or twice a year, coincided with heavy storms in and around Imperial Beach. In Tijuana, flooding killed 11 people. And after a sewage pipe broke, solid waste and more than 15 million gallons of sewage a day streamed into the estuary from Mexico.
The McCoys organized a massive cleanup. They called it “Save Our Slough.”
“They were encouraging us to try to protect the area,” Ed Deaton, who aided in the cleanup with his wife, Linda, told me. Linda shared a black-and-white photo from the cleanup: A 30-something Mike McCoy is wearing work gloves and holding debris in both hands, flashing a big smile. A former Vietnam veteran turned anti-war activist, Ed Deaton told me he got local high schoolers involved. “We wanted to pull together whatever political coalition was required.”
Among the young people who helped was a teenage surfer, Serge Dedina. The cleanup inspired a lifetime of environmental activism: Dedina later co-founded the conservation nonprofit Wildcoast, and, as Imperial Beach mayor in 2018, he championed climate action. “My childhood was spent fighting for the environment here in what would seem to be losing battles,” he told me when we first met almost seven years ago. “You know, stopping marinas and breakwaters.”
It wasn’t just him: A collective took shape and soon grew powerful enough to attract enemies. The McCoys received death threats, and their friend and fellow activist Richard Raymond was shot; the bullet lodged in the roof of his mouth, but he survived. The reasons behind the attack were never clear, but the McCoys maintain that powerful interests had targeted them for their activism.
The thing that stands out the most about Mike McCoy is his youthful, almost naive, idealism. I heard this from everyone I met who knows him. “My feeling was, if we’re gonna have anything left on this planet, you’re gonna have to put your life on the line,” he said, explaining why they kept at it. “You gotta do it.”
The McCoys could feel the momentum building, with more and more people attending city council meetings and pressuring county and state officials. Even so, they were shocked when, soon after Ronald Reagan won the presidency in 1980, a U.S. Fish and Wildlife Service official called them and asked them to meet at the estuary the very next day.
“If we’re gonna have anything left on this planet, you’re gonna have to put your life on the line. You gotta do it.”
After almost a decade of organizing, cleanups and death threats, the McCoys’ dream was at last coming true. The morning after the phone call, Mike McCoy recalled, a pickup truck pulled up next to the estuary and a guy in a Stetson hat and rodeo belt buckle got out. Patricia McCoy called him the Marlboro Man, but his name was Larry Dean, and he soon became the first manager of the brand-new Tijuana Slough National Wildlife Refuge.
The federal government paid Helix $7.6 million, and the deed was transferred to the U.S. Fish and Wildlife Service at midnight on Christmas Eve 1980. Within two years, NOAA, the National Oceanic and Atmospheric Administration, officially designated the refuge and adjoining state land the Tijuana River National Estuarine Research Reserve.
“We learned as we went, you know?” Patricia McCoy told me last summer while we sat in the couple’s living room, surrounded by family photos and books on environmental history. The experience launched her into local and state politics: In 1998, she was elected to Imperial Beach’s City Council, and she later served on the California Coastal Commission, where she advocated for the environment. “You just keep it going, keep going, keep going. And gradually, people began to see its value.”
ESTUARIES ARE ecologically essential: Their shallow, brackish water provides critical spawning grounds for fish and shellfish, making them a favorite stopover for migrating birds. They capture carbon from greenhouse gases and store it in sediments and leaves and roots. Estuaries are also a kind of “natural infrastructure” that can protect coastal communities from some of the worst impacts of climate change, acting as buffers against strong ocean waves and river flooding, alternately absorbing or releasing water. Imperial Beach benefits not just from the estuary’s open space and recreational opportunities, but from its ability to help prevent erosion and deadly floods.
But an estuary can only stay healthy as long as the river and ocean stay connected. Sediment flows naturally into estuaries, both from upstream and the ocean, but if too much of it clogs the river mouth or wetland channels, freshwater and seawater can no longer mix and the tides are cut off, halting necessary flushing and the influx of nutrients and oxygen. These processes make estuaries dynamic ecosystems that can sustain a great diversity of species and habitats, and shield nearby communities from climate impacts.
Jeff Crooks has been studying the ecological history of the Tijuana Estuary for 30 years. He’s the research coordinator for a nonprofit the McCoys founded in 1979 — the Southwest Wetlands Interpretive Association (SWIA) — that, together with the U.S. Fish and Wildlife Service and California State Parks, is one of the primary managers of the estuary. Because of its location, the Tijuana Estuary faces the unique challenge of sewage-tainted water arriving from upstream. But that’s not the only problem. For the estuary to survive, its managers need to help it adapt to new, climate-driven realities that include increased river flooding and higher tides and sediment flows. “Sediment,” Crooks told me, “is the thing that worries me the most about the functioning of this system.”
Even after the wildlife refuge was established in 1980, threats to the estuary remained. That same year, the then-mayor of Imperial Beach, Brian Bilbray, temporarily dammed the Tijuana River to block sewage coming from Mexico. Urbanization was happening on both sides of the border, spurred by the economic growth and free trade agreements of the 1990s. All this brought more pollution and sedimentation. Restoration became a never-ending project.
The latest phase, spearheaded by Crooks, the McCoys and others, will address sedimentation in about 90 acres of coastal wetlands by removing soil from the estuary’s intertidal channels and moving it to the barrier beach. This should restore sensitive habitat and help preserve the estuary’s tidal prism — the amount of water that flows in and out with the tides.
Maintaining the tidal prism is key for the estuary’s future as sea levels continue to rise. One solution is to allow the wetlands to expand naturally onto higher ground and along shorelines, if there’s enough space to do so, and if there is an open river mouth for the water to flow through. This could offset much of the coastal destruction expected to occur with sea-level rise. The stakes are high; if the sediment isn’t removed, the entire ecosystem will be at risk, as well as the protection it offers to the coastline.
Like most nonprofits doing climate adaptation work, SWIA struggles to communicate the importance of estuary restoration. The science is complex. Six years ago, Crooks commissioned a young artist, 17-year-old Audrey Carver, to convey the scientists’ findings about the potential effects of climate change on the estuary. After my chat with Crooks, I headed to a small room at the Tijuana Estuary Visitors Center, where I found four bright latex paintings hanging on a wall.
The first, Lake Tijuana, showed what the estuary would look like if stronger storms carried enough sediment to block the river mouth, creating a natural reservoir of sorts. The second — The Sea Around Us, with a blue foreground framed by the coast — pictured what would happen if that river mouth stayed open and the beaches and sand dunes expanded with sediment from the Tijuana River. The third, Salt of the Earth, showed nothing but salt flats — what the estuary could look like if the river mouth were closed and all the water evaporated in the ever-
rising heat.
Marsh Madness, the last painting, showed what things would be like if the restoration succeeds. It looked a lot like the estuary does today: a rich wetland ecosystem comprising a variety of unique habitats — salt marsh, mudflat, brackish pond, riparian — where a great diversity of plants and animals flourish.
The stakes are high; if the sediment isn’t removed, the entire ecosystem will be at risk, as well as the protection it offers to the coastline.
No people appear in the paintings. Yet they are the reason the estuary was spared, the reason its restoration is ongoing. Few visitors are likely to understand how the estuary’s existence helps them, but without people, one of the last salt marshes in Southern California would simply disappear.
Crooks’ office is inside a prefab building on the edge of the estuary. If you look out of one of his windows from just the right angle, you can’t see the parking lot or the U.S. Navy base next door or any of the nearby developments; instead, there’s nothing but a carpet of dark green that extends uninterrupted until it reaches the sea. Crooks is fascinated by slices of nature like this, the landscapes you can find in densely populated areas that depend on people as much as people depend on them.
The Tijuana Estuary re-quires restoration in perpetuity; climate change and urban sprawl guarantee that. “I don’t think we’re ever going to walk away as if it’s restored,” Crooks told me. “But we’re actually making some progress.” It shows in the way the estuary has been able to stave off some invading shellfish and plants, and in the way trails are carefully designed to keep visitors away from the most sensitive areas. Above all, you can see it in how, as the years go by, freshwater keeps flowing in, mixing with seawater and creating the mosaic of conditions the creatures here depend on.
A FEW DAYS AFTER the 2018 New Year’s holiday, I visited Imperial Beach to witness a harbinger of sea-level rise: king tides, which illustrate what a typical high tide might look like years or decades from now. I stopped at the end of Seacoast Drive, on the border of the Tijuana Estuary, where 8.5 inches of water covered the pavement. Serge Dedina, the surfer and environmental activist who’d gotten his start at the Save Our Slough cleanup, four years into his job as mayor at that point, had come to survey the tide. A city employee stood a few feet away, using a broom to slosh water toward a drain at the end of the street.
Eighty-seven percent of Imperial Beach — including its stormwater, wastewater and transportation facilities — lies within the coastal zone. According to a Climate Central analysis based on data from NOAA and other sources, the city is expected to experience at least one 3-foot-deep flooding event a year between now and 2050.
As the mayor, Dedina was keen to promote climate solutions. So in 2016, the city of Imperial Beach released a “Sea Level Rise Assessment” that sought to identify “politically digestible and economically feasible” adaptation strategies. Soon after the assessment became public, however, it was clear that the most radical proposal — physically retreating from the coast — would not, in fact, be politically digestible: The assessment was shelved after property owners balked at the idea of being asked to move farther inland.
Still, Dedina continued to push for climate action. In 2017, Imperial Beach and two Northern California coastal counties sued more than three dozen oil, gas and coal companies, accusing the fossil-fuel industry of environmental destruction and deceit. The lawsuit was among the first filed by U.S. municipalities against Big Oil. The coastal city’s annual budget was a little over $20 million that year, and Dedina was clear about his aim: to help pay for Imperial Beach’s climate-adaptation and mitigation measures. A week after the lawsuit was filed, Dedina told NPR: “We’re a tough town, and we’ll take our chances in court, because the reality is we have no chance with rising seas.”
Exxon has accused Imperial Beach and other California coastal cities and counties of collusion, claiming they’ve conspired to extort money from the oil companies. Dedina faced harassment, and the case itself has faltered in the courts. Last May, however, the U.S. Supreme Court declined to hear it, meaning that the lawsuit will continue in California state court. It’s a positive, albeit slow-moving, step: Imperial Beach’s climate case is now expected to continue without further delays.
“We’re a tough town, and we’ll take our chances in court, because the reality is we have no chance with rising seas.”
Richard Heede of the Colorado-based Climate Accountability Institute has tracked a growing number of similar climate lawsuits in recent years. “Oil and gas companies are still relatively comfortable in their seats, but I’m hoping that they will lose at least some of these cases, whether it be Imperial Beach or some other community that prevails,” he told me. Still, Heede said, he does not doubt Exxon and Chevron and other companies’ power and willingness to manipulate the legal process. “But I’m hoping that the courts will stand up and recognize that there are very valid legal arguments being made.”
Five years after Imperial Beach filed the lawsuit, Paloma Aguirre, a longtime Wildcoast marine activist who first met Dedina years ago as a coastal cleanup volunteer, became the city’s first Latina mayor. “I said, well, if he can do it, I can do it,” she told me. “I remember talking to him about it, and he looked at me and said, ‘Are you sure you want to do that? You’re a Latina on the border. You sure you want to do this?’”
Aguirre told me just how contentious her campaign was. She faced online harassment and racist death threats. So she reached out to another role model whom she’d gotten to know while working on coastal conservation: Patricia McCoy.
She called one day and found her at home, as usual. “I was like, ‘Tricia, they’re threatening me,’ and she was like, ‘Oh, honey, you don’t know anything. I’ve been shot at. Keep on trucking,’” Aguirre told me, laughing.
It’s been a little more than a year since that conversation, and Aguirre can clearly see how the complex challenges she faces as mayor might prove to be even tougher than political opposition or hate campaigns. Sewage from the Tijuana River closed Imperial Beach’s main beach for most of 2023; there’s always an urgent need for repairs and maintenance on U.S. and Mexico water infrastructure. In the future, Imperial Beach could be flooded for much of the year, filling the Tijuana Estuary with too much sediment, transforming it into a muddy Lake Tijuana-like scenario. There could be less money — or civic or political goodwill — to fight for any of it.
BUT THERE ARE OTHER possibilities. Many of them are already underway, thanks to another estuary defender: Kristen Goodrich. With a background in social ecology and mental health, Goodrich is in charge of the coastal training program at the Tijuana River National Estuarine Research Reserve, which means that she regularly connects with both everyday people and decision-makers over climate change adaptation and conservation.
Last summer, Goodrich took me across the border to Tijuana to meet some of the people living upstream who are trying to prevent more pollution and sewage from reaching the estuary. Walking around downtown Tijuana, we ended up on a bridge, looking down on the concrete channel that carries the Tijuana River’s water — both clean and wastewater — downstream, across the border, and into a treatment facility before it continues to Imperial Beach and the estuary. That evening, I listened to a gathering of Mexican and U.S. researchers and activists discuss their efforts to educate people about waste management. If they could channel U.S. federal funds toward Mexican infrastructure improvements, they said, it would benefit the people and ecosystems on both sides of the river.
The way Goodrich sees it, the estuary could become more than just a place of recreation for residents of Imperial Beach; it could be a binational hub for everyone who is trying to adapt to man-made climate change. “We might be able to deliver some kind of offering where people could come and think about their relationship to each other, their relationship to nature, and think of these things as reciprocal,” she said.
What would that look like? Goodrich doesn’t know. She just knows that the estuary can help us connect the dots of its — and our — ecological history, and give us a way to lighten the load of all the loss and grief and anxiety about the future. I can see it, too. The Tijuana River National Estuarine Research Reserve is already that place for me — a vestige of another era, and proof of what can happen when people work together, holding on to their vision even when it seems futile or dangerous, determined to protect something both necessary and unique.
Ruxandra Guidi is a correspondent for High Country News. She writes from Tucson, Arizona. Follow her on Instagram: @ruxguidi
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This article appeared in the print edition of the magazine with the headline Marsh Matters.
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