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.”