Scientists in California are setting out to create a new kind of agriculture: farming for carbon capture on degraded land in the Sacramento-San Joaquin River Delta.

The concept works like this: researchers will plant things like cattails and tules (a type of rush that grows in freshwater marshes) in parts of the delta that have been subsiding and giving off greenhouse gases thanks to unsustainable agricultural practices in the area. Over time, the marsh plants will reproduce, die, decompose and rebuild the region’s peat soils … all while also soaking up carbon dioxide and creating new, sustainable wetlands.

“This project is an investment in California’s future that could reap multiple benefits over several decades — for California, the nation and the world,” said Roger Fujii, director of the project and chief of the Bay-Delta program for the U.S. Geological Survey’s (USGS) California Water Science Center.

A pilot program that ran from 1997 to 2005 in the western part of the delta ended up rebuilding 10 inches of elevation on an island that had been sinking. Those results have now inspired a three-year, $12.3 million project being funded by the California Department of Water Resources (DWR).

The new project, set to start next spring, will aim to rebuild about 400 acres of wetlands on another island in the western delta. The effort will be led by the USGS and the University of California, Davis (UC Davis).

“The developing carbon market holds great promise for regaining land elevation in the delta,” said David Mraz, chief of DWR’s Delta-Suisun Marsh Office. “It could provide sustainable farming opportunities for delta farmers and an economic incentive to sustain the existing delta levee system.”

Besides creating a new potential market for carbon capture farming, the project could help reverse years of damage to the delta region. Farming practices in the area have caused delta soils to oxidize and sink, in some areas by more than 20 feet. The subsidence has required many areas to be protected by levees, which are now aging and feeling greater pressure.

The project could also help protect the region’s supply of freshwater: farms protected by delta levees convey a large portion of California’s water supplies, serving more than 25 million residents and millions of acres of agricultural land. The goal, Fujii said, is to “assess on a large scale the ability of re-established wetlands on delta peat islands to sequester carbon, reverse subsidence and provide an economically sustainable land-use practice.”