Delta Wetlands Project Tests Carbon Storage Potential

Pilot cultural informed burn project at Twitchell Island helps illuminate the secrets of carbon storage

The Sacramento-San Joaquin Delta has long been recognized for its ability to store carbon, so experts from DWR and partner agencies are exploring the practice of culturally informed burning to accelerate the sequestration process in the region.

"The Delta wetlands are climate powerhouses," said Tyler Anthony, a carbon sequestration specialist with DWR. "These are very ideal locations to sequester carbon."

Before the Delta's transition to farming after the Gold Rush, it was a vast mosaic of tidal and freshwater wetlands that sustained a natural cycle of growth, decay, and renewal that was often enhanced through cultural burning within the wetlands. This process naturally drew carbon dioxide from the atmosphere and stored it in the soil while maintaining ecological balance.

As Delta wetlands were diked to accommodate agriculture in the late 19^th century, the carbon cycle was disrupted. Exposed peat soils decomposed, releasing carbon dioxide, increasing greenhouse gas emissions, and causing significant land subsidence. Today, DWR and academic researchers are reintroducing water and vegetation to Delta tracts to reinvigorate carbon sequestration. It coincides with the parallel interest and renewed attention to traditional land stewardship practices.

Legacy land management

Cultural burning, practiced by California's native communities for thousands of years, is being tested to enhance wetland productivity. The activity removes dead vegetation, creates char (incompletely burned material) and stimulates new growth. It reflects a broader effort to integrate traditional ecological knowledge (TEK) into modern management.

In February, a culturally informed prescribed burn was piloted at Twitchell Island, marking an early test of this approach. Researchers are studying whether such burning can increase long-term carbon sequestration and accelerate subsidence reversal. Although burning releases some carbon dioxide, gases, and particulates, scientists hypothesize that increased plant growth will more than offset those emissions by capturing more carbon in future growing seasons - a concept rooted in TEK.

Don Hankins, a professor at California State University, Chico and a Plains Miwok cultural practitioner, has unique expertise in pyrogeography - the study of the distribution and behavior of wildfires and factors such as climate, vegetation, topography, and ignition sources. He called the burn "an important first step" in revitalizing fire practices across wetlands, floodplains, and riparian ecosystems, noting that many parts of the Delta have gone generations without cultural burning.

"I see connecting these burning traditions and processes back to these lands as essential to their long-term existence and functions in light of environmental threats including sea level rise, biodiversity decline, and climate change," said Hankins. "Considering the amount of change that has occurred within this landscape over the last 150-plus years, this burn has been a great way to bring diverse partners together to steward and learn."

Molly Ferrell, a senior environmental scientist with DWR, said the burn was used to improve habitat and coordinate with carbon sequestration researchers. "As the wetlands will require more burns, it was intended to initiate relationships with other interested Tribes to provide a platform for preserving this cultural practice," she said.

Tapping the economic potential

Scientists with the University of California, Berkeley and California State University, East Bay are collecting detailed measurements before and after burns. Soil cores from Twitchell Island are gathered at different depths and analyzed for carbon and nitrogen. Comparing burned and unburned areas helps us understand how fire influences soil composition and long-term carbon storage.

This work also presents an economic possibility. The voluntary carbon market places high value on projects that reduce emissions or increase carbon removal. This creates an opportunity for the Delta to generate carbon credits that companies can purchase to offset emissions.

Early findings suggest restored wetlands may capture carbon more efficiently than many other ecosystems. As interest grows, researchers and policymakers are exploring scalable frameworks to support carbon credit development in the region. A reliable system for generating and selling credits could help fund further restoration and long-term maintenance. Securing buyers will be critical, as financial incentives are needed to expand carbon sequestration across the Delta.

By reviving natural processes and embracing cultural practices, the region can once again play a significant role in mitigating climate change.

"This is also an important exercise in community building among traditional cultural practitioners and their family bands and Tribes across the broader region," said Hankins.

Photos of the soil sampling and restoration work at Twitchell Island can be found on DWR's Pixel gallery.