In Fairfield, on the northeast edge of California's Bay Area, there is a spot where the land drops below a gravel parking lot and into a ravine. Ledgewood Creek flows through an underpass, just out of sight from passing traffic and across from a Home Depot. On a hot day in early September 2024, researchers from UC Davis are in the creek, setting up transects to measure its size and shape.
Olive trees, willows, blackberry brambles and dried grasses share space here with scattered bits of trash - soda bottles, plastic bags, broken toys, paper plates, a pizza box. A woman shuffles below the shade of an oak. An empty wheelchair is parked under a tree. A shirtless man on a bike emerges from a trail and quickly apologizes for "being in the way."
He's not, Professor Gregory Pasternack assures him: "We're just researchers from UC Davis measuring the stream."
They are joined by Costanza Rampini, an associate professor of environmental studies at San José State University. She and her research team are conducting trash surveys and interviewing unhoused people living along this stream.
Together, their research is part of a two-year study of urban stream corridors throughout the Bay Area centered on climate change and unhoused people. Funded by a Climate Action Seed Grant from the UC Office of the President, the work aims to promote resilient urban streams and help find compassionate solutions to the interconnected issues of climate change and homelessness, which are often missing from current policies.
As homelessness and climate change increase, urban streams become more susceptible to flash floods, heavy winds and pollution and more dangerous to those sleeping alongside them. The research could yield data to better understand how to make positive changes and inform policies.
"It is incredibly important that we think about homelessness as it relates to climate change because people who live and sleep outside are the most climate vulnerable," Rampini said. "They are our number one front-line community."
Climate change and extreme weather in the U.S.
More than 771,000 people experienced homelessness in the United States in 2024 - the highest on record, according to the U.S. Department of Housing and Urban Development. In California, more than 187,000 people were homeless in 2024, with only a third using shelters, exposing most to increasingly extreme weather.
During the 2024 rainy season, more than 50 atmospheric rivers soaked the West Coast, with wind and storm damages killing several people and costing billions of dollars.
"I don't think people realize how many thousands of people have moved into the stream corridors throughout the Bay Area," said Pasternack, a hydrology professor in the UC Davis Department of Land, Air and Water Resources. "The ability to escape the river diminishes when you have rain and wind together."
Federal and state legislation last year prompted vast sweeps of homeless encampments from public spaces, with many unhoused people moving further into hiding, alongside underpasses, woods and streams.
As policymakers and communities struggle to balance the needs of society and the environment, the research team has been visiting dozens of encampments to learn first-hand what is happening in the Bay Area's stream corridors, listen to those living there, and better understand the nature of coexistence.
"All of the current conditions and concerns are expected to worsen with anticipated climate-change impacts," Pasternack said.
His team surveyed 164 stream sites in 2024. They'll combine their onsite data collection with remote sensing, AI and machine learning to understand how the entire Bay Area stream network functions, what conditions people prefer for encampments, and what may be expected with climate change.
"But the first step is getting out into the stream corridors to learn about the people and sites," he said.
A love of nature
This site at Ledgewood is surprisingly free of tents - a sweep took place just the night before.
"There are movements to move people out of encampments and out of creeks," Rampini said. "What can we provide so folks actually choose these other services rather than spending millions of dollars on things people don't really want?"
Encampment residents themselves, who Rampini often calls "campers," are helping to answer that question. Her team has interviewed more than 240 people living in 28 encampments along streams similar to this one - from coastal Half Moon Bay to San José's Coyote Creek.
Team members carry clipboards holding a 45-question survey and invite encampment residents to share their perspectives. Questions range from personal history and pets to health, drug use, occupation, food, hygiene, the weather and the good and bad things about living along the creek.
Again and again, survey participants note their love of nature.
At Ledgewood, a woman with blonde and purple hair and bright blue eyes stands next to her partner, who sits in a wheelchair, his infected foot stretched in front of him. She's been homeless for eight years. What does she like about living along the creek? Watching the turtles and birds, and "when the baby ducks come, it's beautiful."
The researchers ask the man: "Would you accept housing?"
"Yes."
"What kind?"
"Anything other than a shelter."
No one living here speaks well of shelters, viewing them as a last resort. Many think they are too restrictive with respect to pets, guests, curfews, personal relationships and belongings. Yet all survey respondents say they would accept housing where they are treated with dignity and retain personal autonomy.
'You look like you belong to someone'
Rampini and her team cross the creek and move into the underpass tunnel. They walk past ramen cups, ice cream tubs, a hand vacuum and a clothes washing station assembled from a wooden pallet. Looking out from the graffiti-marked tunnel is a park-like view. Trees bend over the creek, reflecting light as cattails cluster by the pale green water.
A 47-year-old man says he likes how relaxing and quiet it is along the water. When it rains, he moves under the tunnel to stay dry. If it rains hard, he's seen the water rise as much as 5 feet here. He's been homeless for 10 years, living outside.
Are there any helpful groups? He mentions the nonprofit Community Action helps connect people with apartments. He'd accept housing "if it was a real house," but not a shelter. He wouldn't accept a curfew but would agree to a no-drug policy.
A black cat skitters up to Rampini as the man talks. "Hi sweet potato!" she says, scratching behind its ears. "You look like you belong to someone," noting its collar. She sits cross-legged on the ground with her clipboard and scoops the cat into her lap.
Pets are another reason some unhoused people are wary of shelters and prefer to live outside, where they won't be separated and where their pets can roam more freely.
'Dude, where do we go?'
Laughter and music echo from another side of the tunnel. Seven campers have arranged lounge chairs, a coffee table and an umbrella into a makeshift living room. They are playing karaoke and watching puppies wrestle playfully. Traffic rumbles above, sending vibrations through the concrete below.
Rampini asks about their social dynamic. "We hate each other; we love each other," answers an older woman with short spiky hair who lives here with her adult son. "We have each other's backs."
She cuddles her chihuahua while sitting in a lawn chair and trying to keep a small white dog at her ankles quiet, while the researchers ask the group about extreme weather.
"What do you do in the heat?"
"There's good shade here."
"Have you ever used a cooling center?"
"What's a cooling center?"
"Have you ever received a warning before a major storm?"
"Never."
"Are any groups helpful?"
They say nonprofits give food, water, and clothes, and law enforcement gives grief: "They just move us. They don't have nothing for us."
"In an ideal world, what can nonprofits and others do to actually help?"
"A place where we can go to just be, not messed with," the woman says. "Just give us a corner to sit for awhile until the sun or the rain goes down. Instead they say, 'Just get out of here!' But dude, where do we go?"
"Every two weeks, we have to start over," adds a quiet blonde man sitting in the corner. "It's hard to find a job when you have to keep moving. You need stability."
Few extreme weather warnings
Through hundreds of interviews like these, common sentiments surface: Like many people, streamside campers want to live near water for its beauty and solitude. They appreciate the trees, breeze and wildlife that streams offer. They want housing but not a shelter. They want autonomy and to be treated with respect. They have loved ones. They love their pets. They look for places that support those needs but are also near services, like a place to shower, shave, get food, health services or use a restroom.
It is no small wonder, then, that unhoused people would look to places like the Ledgewood site, which offers the creek, is relatively out of view, and is just around the corner from a Target, Home Depot, plasma center, bus station and McDonalds. Yet it's also subject to law enforcement sweeps and instability. And the stream, while lovely in parts, is heavily trashed and capable of dangerous flash floods and heavy winds during winter storms.
Rampini's surveys show that homeless residents rarely receive emergency warnings of extreme weather events. One woman described plucking her puppies out of floating water and going downstream after a storm to collect belongings that had washed away.
"This kind of research takes awhile because you can only operate at the speed of trust," Rampini said. "But I hope it creates a more informed dialogue about homelessness and the environment and, we hope, provide guidance."
Beyond rewilding
In the field of conservation, restoration has largely focused on rewilding - returning natural areas to what they once were.
"Since the 1980s the idea of putting things back to nature has tried to eliminate the role of humanity," Pasternack said. "For encampments, there's an opportunity. If people live here, if this is their home, what can we do to get them services, their buy-in, make them part of the solution?"
That is the spirit behind coexistence conservation - embracing nature as it exists while restoring natural functioning where we can.
"You have to take nature as it is," Pasternack said, "I don't think we can throw away urban environments and say, 'Life doesn't work there.' We have an obligation to resolve ecological functioning, but not where everyone has to leave. We have to coexist."
Pasternack and Rampini want to open people's eyes and minds to strategies that - informed by science and people experiencing homelessness - may be useful in protecting the state's waterways, people and environment.
Finding solutions
Rampini has been studying flood-prone, vulnerable and unhoused communities throughout her career - from India to New Orleans and Santa Cruz. If she had a magic wand, what would she do to help unhoused people and the environment?
She'd partner with an organization to monitor water quality. Then she'd provide porta potties that are serviced regularly, trash cans, mobile laundry and shower services. A storage program could allow people to store belongings while they do errands, jobs or seek access to cooling or warming centers during extreme weather events. Then she'd look to the monitoring data to see if those services improved the river's health or the people's lives.
"If the complaint is, 'this is bad for our rivers,' housing is not the only solution," Rampini said. "It's easier for people experiencing homelessness to get new clothes than to wash the ones they have. That doesn't seem like a dignified way to live, like you don't really even have your own clothes."
She notes a nonprofit in Santa Cruz that collected unhoused people's laundry for them once a week and washed them at a local laundromat.
"If we did that, could we see less litter of clothes in the river? I would think so, but there's no data to prove it," she said, adding that clean clothes reduce the stigma of "looking homeless," allowing people to enter stores and use bathrooms more easily.
She'd also like to see people in streamside encampments compensated for cleaning up the river - providing a job while encouraging stewardship of the river.
"I think these things would snowball into something bigger, rather than just seeing what kind of food stamps or vouchers we can give," she said. "That's my dream."
Exploring options
At its midpoint, the project is already spurring small actions. Pasternack is currently submitting a proposal to the National Oceanic and Atmospheric Administration to fund a natural hazard warning strategy for encampments along Bay Area streams.
Project partner SOS Richmond plans to pilot a creek restoration skill-building program that offers opportunities for unhoused people living on creeks to be stewards of those creeks.
This year, the researchers will assess more stream corridors, use machine learning to help predict the scope of stream encampments, assess the region's vulnerability and resilience, and look at future scenarios of climate and socioeconomics through 2100.
"We don't just want more science," Pasternak said. "We want to ease suffering. Our goal is to get answers."
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