The dredging of Easkoot Creek and the restoration of a wetland in the Golden Gate National Park may be the best answer to the threat of creek flooding in the coastal town, according to a new study by the county.
At a public meeting at the Stinson Beach Community Center on Saturday, county staff presented 10 options for mitigating the impact of creek flooding—events that have left distinct pictures in the minds of locals who saw a neighborhood’s main access road disappear underwater and rowboats and kayaks paddling around town.
Although the community will ultimately decide the path forward, the study concluded that the best benefits for homeowners would come from combining significant dredging of Easkoot Creek with the recreation of a historic wetland. (Large-scale dredging hasn’t taken place for over two decades because of sensitive fish habitat.) Under this plan, 24 low-lying homes that flooded on New Year’s Eve in 2005 would have avoided such a fate, the county said.
That solution is not only expensive, however, but hinges on making a persuasive case to Golden Gate National Recreation Area that protecting a swath of private property is worth reducing visitor services on public lands. A proposed channel that would divert water from the creek to the wetland would eliminate some parking spaces and picnic areas.
The chief of natural resources for the recreation area, Daphne Hatch, said the park wants the county to consider the tradeoffs between wetland enhancement or restoration and the already limited parking at Stinson Beach.
Park service comments from a draft version of the study expressed concerns about the visual impacts of a bypass channel, which it described as “essentially a long large ditch.”
Ms. Hatch said the county would need to establish a compelling need for using public land, adding that the updated general management plan for the recreation area, which should be released this spring, did not evaluate such a restoration because of visitor use levels.
And, she added, the study declined to address sea level rise. “That’s an important next step that needs to be taken so we understand the big picture, so we understand what’s happening on both sides,” Ms. Hatch said.
The sea level on the California coast south of Cape Mendocino could rise between five to 24 inches by 2050, and between 17 to 66 inches by 2100, according to a 2012 report by the National Research Council.
The low-lying community, said Sam Veloz, a spacial ecologist with Point Blue who works on modeling climate change impacts, “was already vulnerable to storm events when it was first designed. It doesn’t take too much science to realize that sea-level rise is going to make that problem worse.”
The current problems in Easkoot Creek stem from major storms that pull sediment from Mount Tamalpais into the lower reaches of the creek and the expense of dredging, which requires numerous permits. In 2008 a grant from the Department of Water Resources prompted the county to undertake planning efforts in five of Marin’s watersheds, which resulted in the recently completed study.
The proposed dredging would lift about 3,100 cubic yards—about 25 semi-trailer loads—of sediment out of a section of the creek from Arenal Avenue to Calle del Arroyo. “If we were to dredge the creek channel, it makes the entire creek deeper and a bit wider. It basically resets the conditions to 1979 elevations,” said Chris Choo, a senior watershed planner for Marin’s Department of Public Works.
Since the late 1990’s, the flood control district in Stinson Beach has managed vegetation on an annual basis and spot-dredged every few years under bridges—what Mr. Schecter said is called “gloryholing,” in which sediment is scooped out of the creek with an excavator.
But no major dredging has occurred in the creek for a couple decades. The designation of coho salmon and steelhead trout as endangered species requires protective permitting that makes it a lengthier, much more expensive process.
In order to secure permits for dredging, Choo said, the county would take measures to minimize impacts to fish and wildlife, like working in the dry months and avoiding bird-nesting season. Since fish can still be found in the creek during dry times, a biologist would be onsite to temporarily relocate any that are stumbled upon. New beneficial fish habitat would also be created.
The county’s favored combination of dredging and wetland restoration—which would take place near an area once called Poison Lake, named by moms eager to dissuade their children from playing in its muddy waters, locals say—is one of the most expensive proposals, estimated at $3.5 to $4.5 million. That number does not include the cost of an environmental impact report or annual operation and maintenance.
And grants for maintenance projects like dredging are scarce, Ms. Choo said.
Joan Lamphier, a Stinson Beach resident, said that whatever is done should not been done halfway—but it should also be affordable. “I agree: flooding is critical. But I think the financial aspect is really important,” she said.
A member of the flood control zone who has lived in Stinson for almost four decades, John Washington, said that although not everyone in Stinson is flush, the town is not exactly impoverished. Still, he hoped the need for a financial commitment does not spur a divide between homeowners within the flood zone and those outside it. “What’s more important to me [than cost] is that we have an alliance between people who are in flood-inundated areas versus people who are not. I think we have to be careful of, ‘Is it me or is it the we?’ I prefer the latter.”
At least one community member has taken it upon himself to protect his home. Toby Bisson, the president of the Stinson Beach Community Center, raised his home 14 feet in the air to prevent it from flooding.
Another resident, Barbara Williams, who sits on a technical advisory committee for the county, has been thinking about raising her home, too. But even if she did, she admitted, “You need to address the problem. Even if homes are raised, the roads are blocked. You’re still out of commission.”
Visit marinwatersheds.org/stinson_beach.html to read the study and take the survey.