Sonoma Land Trust builds ‘living shoreline’ to thwart erosion at Sears Point
Julian Meisler stood on a human-made levee at low tide along the shore of San Pablo Bay, surveying 1,000 acres of a dark brown, mostly barren mud flat.
“That’s exactly what we want to see,” said Meisler.
He is the project manager of Sonoma Land Trust’s 15-year campaign to restore wetlands intended to protect the Highway 37 corridor — with both a roadway and rail line — from flooding exacerbated by sea level rise.
And now the levee, a victim of erosion from wind waves, is being fortified by an unprecedented restoration project using hundreds of trees — some salvaged from wildfire burn areas — to blunt the waves and promote wildlife habitat.
It’s been six years since the Santa Rosa nonprofit’s Sears Point project breached the levee built 140 years ago to create farmland, and tides have since deposited two to four feet of sediment in the nascent wetlands.
At high tide, the mud flat becomes a lagoon up to two and a half feet deep, harboring shorebirds, waterfowl, river otters, bat rays and leopard sharks. People ply the water with canoes, kayaks and standup paddleboards, while hiking trails lead along the shore in what is now the San Pablo Bay National Wildlife Refuge.
The project’s ultimate goal remains years away, when six feet of sediment gives root to vegetation transforming the wetlands into a verdant marsh, teeming with wildlife and absorbing high tides.
But nature is not easily manipulated along the barren baylands south of Lakeville Highway’s intersection with Highway 37. Wind-driven waves six to eight inches high are undermining about 2 miles of the levees — Meisler calls them “young shores” — that keep water from flooding farmlands along the highway.
True to its preservationist ideals, the land trust abstained from the conventional response to shoreline erosion: a line of immovable boulders that blunt waves but provide habitat for nothing but rats, Meisler said.
Instead, the $900,000 project envisions a “living shoreline,” installing about 300 logs, 15 to 25 feet long, strategically embedded and anchored next to the levees, with mud, gravel and rows of planted cordgrass in front of the logs.
“We give nature the ingredients and nature bakes a cake,” said Stuart Siegel, owner of Siegel Environmental, a consulting firm hired by the land trust to design and oversee construction of the project.
The wood, mud and gravel are all recycled, with the logs, donated by Caltrans and PG&E, salvaged from road projects, burn areas and utility line clearing. The donation, which included stacking the logs at the site, saved the land trust $130,000.
“The methods we are using have not been done before in the San Francisco Bay and there are no guarantees,” Meisler said.
Construction is expected to last several more weeks, with the 2.4-mile Bay Trail-Eliot Trail and the 0.3-mile Dickson Trail remaining closed, The 1.4-mile Bay Trail-Sonoma Baylands Trail will remain open at Port Sonoma only.
Project funding came from a California Wildlife Conservation Board grant, motivated by the “need for innovative pilot projects to advance the science of ecological restoration” in the face of accelerating sea level rise, Meisler said.
Restoring 1,000 acres of wetlands accounts for “a tiny fraction of what was lost over the past century and a half,” he noted. Most of the other lands bordering San Francisco Bay are covered with housing, industry, hospitals and airports
While the use of logs to protect levees is novel, it imitates the natural conditions from before the bay’s two principal rivers, the Sacramento and San Joaquin, were dammed and diverted and fallen trees wound up on the bay shoreline.
Wendy Eliot, who retired last year after 21 years as the land trust’s conservation director, zeroed in on restoring the wetlands along Sonoma County’s pancake-flat bayshore, typically overlooked by motorists on Highway 37, a critical link between Highway 101 and Interstate 80 in Vallejo.
At Sears Point, the highway, already a victim of chronic flooding, is just one foot above sea level now, with the water projected to rise nearly two feet by 2050.
Wetlands are “natural infrastructure” that act as a “giant sponge,” absorbing water from the bay’s biggest tidal fluctuations, known as king tides, as well as heavy rains, then slowly releasing it, according to Eamon O’Byrne, the land trust’s executive director.
He and others envision wetlands and an elevated Highway 37, looking like the Yolo Bypass on I-80 west of Sacramento, as protection for the key transportation corridor.
As sea level rise accelerates, Meisler said the issue of shoreline erosion will become increasingly widespread and the land trust will monitor the levee protection project through 2030.
“If we are successful, we hope this nature-based approach can be applied widely,” he said.
You can reach Staff Writer Guy Kovner at 707-521-5457 or firstname.lastname@example.org. On Twitter @guykovner.