The perils of rising seas, increased incidents of coastal erosion, billions of dollars of at-risk infrastructure and a push for a regional response to addressing the effects of climate change are highlighted in a first-of-its kind study for San Mateo County.
Community meetings will be held this month after the county’s Office of Sustainability released its draft Sea Level Rise Vulnerability Assessment. Its first major report is part of its Sea Change SMC program, an initiative that began about two years ago. Determining what’s at risk is one of the first steps in the regional effort to adapt and prepare for climate change.
Short of taking action, the report notes that nearly $1 billion worth of property is at risk to near-term flooding, and nearly $34 billion is vulnerable to erosion and long-term flooding, according to the report. Bay Area seas have already risen 8 inches in the last century and scientists predict another 5 inches to 2 feet of additional rise in the region by 2050, according to the report.
While the county is surrounded by beauty of the San Francisco Bayfront and California coastline, these features make it one of the most at risk for sea level rise in the state.
“The report provides a snapshot of our current vulnerability, it’s not all what the future will bring, there are risks today,” said Dave Pine, vice president of the Board of Supervisors. “The reason San Mateo County is the most vulnerable county in the state is because of our historic land use development patterns where we have development to the edge of the Bay and in many cases into the Bay on Bay fill.”
From Brisbane to East Palo Alto and San Mateo to Half Moon Bay, a range of vital public and private infrastructure could be at risk. Schools, homes, wastewater treatment plants, airports, major highways, landfills, railroads and wildlife habitat are all vulnerable.
The county consists of 53 miles of Bay shoreline, 11 miles of levees and floodwalls, 41 miles of berms or embankments and 7,100 acres of wetlands. San Mateo County has 56 miles of coastline, nearly 60 acres of wetlands, 300 miles of rivers or streams and a variety of recreational assets. At 2 feet of sea level rise, San Francisco International Airport would be flooded. If the Bay was to rise 3 feet, Highway 101 as well as neighborhoods in Burlingame and Millbrae would be inundated, according to the report.
“We expanded into the Bay in places like Foster City, Redwood Shores and the airport. So those are the places that are most vulnerable where we constructed or built our major population and business centers,” Pine said.
Should some of this infrastructure be compromised, it could result in even wider-spread effects to the entire community, said Hillary Papendick, the county’s climate change and adaptation manager. Basic equipment like pump stations that move stormwater and sewage away from homes are examples of infrastructure upon which many may not realize their communities depend, she said.
“If we were to see a flood that would take out some of these critical systems … we would see far-reaching impacts. Everyone in the county would be affected if the water treatment plants stopped functioning or the highway were flooded,” Papendick warned.
But the picture isn’t completely bleak. The vulnerability assessment is the first step in hopefully promoting a regional response early enough to help cities and the county adapt.
“The good news is there’s a number of things we can do in the near term and long term to help reduce risks,” Papendick said.
The assessment doesn’t prioritize particular projects or strategies that should be used. That will come after further collaboration with stakeholders, deciding what type of criteria should be used to evaluate improvements, and then outlining an implementation plan, she explained.
On Tuesday, the report was presented to the Board of Supervisors before two community meetings are held in Burlingame April 25 and in Half Moon Bay April 29.
Some of the most fruitful aspects of preparing the report were engaging stakeholders from different cities, educating the public about sea level rise and working toward promoting a coordinated regional response, Papendick said.
Plus, improvements in one area could have the unintended consequence of negatively affecting another. Furthermore, funding these types of improvements will be challenging, particularly for individual jurisdictions. This makes a regional approach even more pertinent, she and Pine explained.
“Flooding and sea level rise don’t respect jurisdictional boundaries and in the years ahead, we will have to work in a collaborative and coordinated way to defend against sea level rise,” Pine said.
Plus, last minute, reactionary responses are generally less cost effective than advanced planning. Regional or multi-city approaches might include large-scale wetland restoration that act as a natural horizontal levee and traditional sea walls. On a city basis, updating zoning ordinances and building codes to reflect risk or considering strategic retreat from at-risk areas are other initial actions communities can take, Papendick said.
Other possibilities are to construct new infrastructure or buildings with sea level rise in mind. For example, building flexible facilities that could theoretically be raised or modified to account for rising seas, she said.
One of the most timely and pertinent examples of that concept is Foster City’s plan to raise its levee, which protects the entire 4-square mile community from potential flooding. Mandated by the federal government to raise it a certain amount, Foster City has opted to build it in such a way it could be more easily raised to accommodate future sea level rise.
Papendick said there are already seven projects various communities are working on along the Bayside in an effort to address climate change and protect against flood risks.
Predictions vary from a risk of flooding today in the event of an extreme storm, to the seas rising 6 feet at the end of the century. While some remain doubtful of these forecasts or whether mankind is having an effect, Pine noted climate change is coming.
“Even if all carbon emissions were stopped tomorrow, sea level rise will continue to pose challenges to our county for generations to come. That’s because the heat that’s already captured in the ocean takes time to melt these ice sheets,” Pine said. “It’s a problem that’s not going away and we’ll have to deal with it in the decades ahead, one step at a time. This report marks the beginning of that effort.”
Visit seachangesmc.com for more information about the assessment and details about the upcoming community forums.
(650) 344-5200 ext. 106