Student-led bioswale project filters runoff before it reaches Copeland Creek
Native plants and biochar help make campus water systems more resilient
When biology major AJ Staal looked at the parking lot outside Sonoma State University’s Environmental Technology Center, they saw an opportunity to rethink how water moves through campus — and to protect the Copeland Creek watershed in the process.
Staal, who is from Torrance and expects to graduate in 2027, led the design and installation of a new bioswale that captures stormwater runoff from a nearby parking lot, filtering pollutants and sediment before they can reach Copeland Creek.
A bioswale is a planted basin designed to absorb stormwater runoff. Staal’s project combines native plants, biochar, subtle landscape grading, and a rock-lined bowl to slow and capture water that would otherwise flow directly into storm drains.
The volume of the bioswale basin is 150 cubic feet, capable of holding a little more than 1,100 gallons of water at a time. This amount of water can be absorbed in an hour or less, depending on the length of time between rainfall events. While the bioswale cannot yet absorb all the runoff from the parking lot, its absorption capacity will increase as the plantings get established and set their roots.
“Water that would normally be going down the storm drain, taking pollutants and sediment into the creek, is now being absorbed,” Staal said. Sediment runoff can degrade habitat for species such as salmon.
The project received funding through a WATERS Collaborative grant awarded by SSU’s Center for Environmental Inquiry and Sonoma Water in October 2025. Construction of the bioswale took place from April 2-16.
Last month, Staal’s work also earned the award for best water research poster at SSU’s Research, Scholarship and Creativity Symposium.
The bioswale uses biochar — a charcoal-like material known for improving soil health and water retention — to filter pollutants commonly found in parking lot runoff.
“Biochar is really good at absorbing heavy metals and hydrocarbons like oil and grease,” Staal said.
SSU landscape manager Christa Irwin helped Staal identify biochar as a potential solution and made the connection with a local source: East Bay Regional Parks district had recently completed a large-scale eucalyptus removal project and used a low-emission carbonizer to turn the debris into biochar.
The bioswale’s native plants also play a major role in filtering water and supporting biodiversity along the creek corridor. The planting palette includes scarlet monkeyflower, narrowleaf milkweed, yarrow, hummingbird sage, and California mugwort, along with native grasses and grass-like plants such as valley sedge, common rush, and California fescue.
“The more of these bioswale or bioretention areas are installed, the better our water quality will be,” Staal said.
The project grew out of Staal’s involvement with the agroecology garden, which showcases sustainable, organic, agroecology practices, and demonstrates how these practices contribute to both natural biodiversity and human health.
“The area where the bioswale is now installed is the entrance to the garden for most people,” Staal said, adding that one goal was to make the space outside the Environmental Technology Center more inviting to visitors and volunteers.
One of Staal’s key collaborators was Gabe Fowler, a landscape and irrigation technician on the SSU Facilities team. Fowler began working with Staal during the project’s phases not long after completing a water-wise landscaping certification course through Sonoma Water.
Fowler also brought relevant experience from his previous work as an independent landscaping and irrigation contractor, where he built bog gardens and other water-retention features designed to keep runoff out of storm drains.
“I was very impressed with AJ’s initiative, knowledge, and leadership on the project,” Fowler said.
Fowler recently completed installation of drip and spray irrigation systems to help establish the bioswale’s new native plantings during dry months.
Staal described the project as a hands-on education in “water quality and using native plants as infrastructure to benefit ecosystems and humans.
“It also proved to have a lot of civil engineering aspects to it,” they said of the project.
Caitlin Hachmyer, a lecturer in SSU’s Geology, Environment and Planning Department, served as Staal’s faculty mentor.
Staal said the project was made possible by support from across the SSU community, including advice from an SSU alumnus who works for Santa Rosa Water, native plant contributions from geology lecturer Heidi Herrmann, volunteer help from students in Dr. Lisa Patrick Bentley’s Climate Change Biology class (BIOL 351), and support from California Climate Action Corps fellows.
To encourage community participation during five days of digging and planting, Staal even brought a tamale truck to campus.
Staal said projects like the bioswale are increasingly important as climate change intensifies storm events and pressures water systems.
“We are dealing with a lot more frequent extreme rain events, followed by extended periods of drought and water shortage, so how do we store that water, recharge our groundwater for a more resilient water management system?” they said. “Native plants and biochar and a little bit of minor topography changes are a good way to capture that stormwater.”
Staal hopes the project helps inform students and people in the community about the resilience benefits of bioswales and rain garden areas.
Looking ahead to life after their 2027 graduation, Staal hopes to continue working with native plants through restoration, land stewardship, or native landscaping.
“I’m happy as long as I work with native plants,” they said.
Staal also encouraged other Seawolves interested in similar projects to get involved. “If they are interested in more projects like this, come talk to us at the agroecology garden.”