Sears Point after a levee was intentionally breached, restoring tidal flow
photo credit: (Credit: Sonoma Land Trust)
A new phase of a wetlands restoration project is set to get underway at Sears Point in August. The 1,000 acre project, fallowed grazing land once eyed for a casino, is instead creating habitat for shorebirds, a refuge for salmon smolts and other fish, along with protecting surrounding low-lying areas from flooding.
The levee was breached in 2015.
Thursday evening, Peter Baye, a Coastal Ecologist and Botanist consulting for the Sonoma Land Trust, which is behind the project, said changing bay conditions and lessons from previous restoration work are helping shape the project.
Baye said over the last quarter century, a slow shift occurred, with more sediment washing out the Golden Gate than being deposited by river systems feeding it. "There's been a shoreline shift from widespread net seaward growth or progradation, fat mudflats, growing marshes to retreating marshes." Now sediment must be brought in. Clusters of pioneering grasses will be strategically added, enabling other plants to colonize the area. The second phase will add partly buried logs, reducing the force of waves, and giving plants a better shot at getting established. Earlier efforts generally used rock as a wave break, effective at slowing wave energy, but presenting an inhospitable surface for plants.
In addition to wildlife habitat, healthy marshes can absorb small waves and reduce flooding impacts nearby. That will become increasingly important as sea levels rise further. The project however is limited, Baye said.
"So much of our tidal lands restoration planning and engineering is still built along the 19th century configuration of levees and the 19th century configuration of roads and railroads, and it obviously makes no ecologic, geomorphic or engineering sense, it's just what we've inherited."
Baye said the restoration won't conflict with highway 37 or future plans for the roadway. Baye said if Caltrans eventually puts the highway and adjacent rail line on a causeway, levee removal could greatly expand both habitat and limit vulnerability to flooding.