During high-water events like last week’s king tides, Marin County’s densest communities began to flood.
Near the port, saltwater flowed from beneath an apartment building, flooding a restaurant terrace and causing cracks in the foundation and cement walls. It gradually raised the tires of cars and pools parked on evacuation routes. Multi-story buildings loom like islands.
For a number of reasons, San Rafael, a community of 12,000, is the Bay Area’s most vulnerable to sea level rise. It sits on a canal that leads to San Francisco Bay, and part of it was originally built on soil used to fill wetlands and the bay itself—a topography that caused it to sink as the ocean and bay rose. Even in the short term, a major earthquake or a massive 100-year storm combined with high tides could cause several feet of flooding, experts say.
“People don’t necessarily realize this is happening and the risks,” Rita Mazarigos, a member of the community’s sea level rise steering committee, said in Spanish through an interpreter. She said displacement is an ongoing concern. “There’s not enough affordable housing here, so if there’s flooding, it’s a serious situation for everyone who lives here.”
Community member Raquel Sanchez (left) joins University of Arkansas associate professor Kevin Befors (green jacket), UC Berkeley civil and environmental engineering students Amelie Bernex and Angela Gil, community member Javier Jose and San Rafael City Management Analyst Walter Gonzalez to view storm drains on Harbor Street during a Grand Tide event hosted by the Canal Alliance on Dec. 6 in San Rafael. (Yalonda M. James/SF Chronicle)
The San Rafael area, known as the Canal District, is the densest neighborhood in the Bay Area after Chinatown. It’s also the most racially segregated area: predominantly Latino and working-class, and one of the few low-income areas in Marin. Most of the land and buildings along the Channel are privately owned, leaving little room to build seawalls or levees to protect against emergency flooding and the long-term threat of climate change.
“All of these adaptation options would require some infrastructure between the bay and downtown,” said Kate Hagemann, climate adaptation and restoration planner for the city of San Rafael. “That’s not possible right now.”
One looming problem is that the community’s two main exit roads are below peak tide. They are already vulnerable to tidal flooding and are expected to be permanently submerged by 2050, according to the Marin Transportation Authority’s recent sea level rise study, which recommended raising the road.
Consultants released a draft feasibility study for the city in October that offered alternatives for protecting the coastline and surrounding communities. One alternative would be for the government to purchase up to 86 of the more than 100 private properties along the coastline, or at least purchase easements on those properties to create shoreline protection and then sell the land back to private developers. The study found that this route could take at least two decades to complete and would cost $211 million to acquire.
“All of these are seven steps forward,” said Hagerman, who previously served in a similar role in Miami-Dade County. San Rafael is exploring those options while soliciting feedback from the community, she said. “No choice has been made yet.”
On December 6, the San Rafael River experienced high tide. The canal zone is highly vulnerable to sea level rise. (Yalonda M. James/SF Chronicle)
The study also proposes ideas for immediate fixes, such as raising areas along the canal above the current highest tides and upgrading pumping stations that are already overwhelmed at high tide and are designed to only handle stormwater, not seawater. Along with other long-term strategies such as building levees, the improvements could cost about $719 million to $1.9 billion. Research shows the city may need to bring in outside funding and will be responsible for at least 35% of projects receiving federal support.
Community members say such repairs don’t come soon enough because flooding is already a chronic problem. Mazarigos’ husband lost his car in a flood two decades ago. Raquel Sanchez, who has lived in the Canal Zone for 20 years, said water accumulates in the parking lot during heavy rains, causing moisture inside her car. Moisture seeped into the house where she and her sons lived, causing mold to grow on the walls and stain her clothes.
“When I moved to another building, I thought it would be better. It had the same problems,” said Sanchez, who moved three times in the neighborhood and later outside.
In addition to homes populated by mostly working-class residents, thousands of people work at places like nearby wastewater treatment plants and recycling centers, which are also vulnerable, Hagman said.
Community member Jose Arce uses a salinometer to read salinity levels in water samples collected from San Rafael Creek on December 6 during a spring tide event organized by the San Rafael Canal Alliance in California. Canal Zone residents collected data, measured water levels, and recorded their site visits as part of a citizen science project aimed at educating residents about flood risks and gaining more information. (Yalonda M. James/SF Chronicle)
“It’s really huge,” said Isabel French, director of marketing and communications for the Canal Alliance, a nonprofit that provides legal and other services to Latino immigrants. “This is not a question of the future, it is a question of now.”
A 2020 vulnerability study by the Bay Conservation and Development Council, the state agency that oversees sea-level rise planning in the San Francisco Bay, found that San Rafael has the highest proportion of the population at risk of flooding from the effects of early sea-level rise compared with 30 other areas in the region.
“In most places around the bay, it could take 20 years to repair a bathtub crack,” said Kristina Hill, a professor in the Department of Landscape Architecture and Environmental Planning at the University of California, Berkeley, referring to the vulnerability of shorelines as sea levels rise. “In San Rafael, the tubs were cracked. They probably had 10 years to really repair the cracks.”
Parts of eastern San Rafael have already sunk several feet in overfilled areas, and some areas are expected to sink another 2 to 4 feet in the coming decades, according to the city. Like many areas in the Bay Area, much of the area was built on bay dirt or was filled with construction debris or other materials that filled parts of former wetlands and bays.
Sea levels have risen 3 inches in the past 25 years and are expected to rise another foot in the next 25 to 45 years. According to the feasibility study, this is considered a tipping point and if no action is taken, economic losses could reach $130 million to $210 million. By then, the canal will have crossed the barrier once a month, which would “disrupt the normal functioning of the area” “through regular vehicular flooding, salt corrosion of infrastructure, business disruption, market perceptions of risk and a potential collapse in property values,” the study said.
“We’re going to live in this era of flooding, where flood events are going to get worse and worse. They may seem like small disasters, but ultimately the water doesn’t go away,” Hill said. Hill said his graduate students just completed a course dedicated to finding solutions to short- and long-term flood risks in the canal zone, including earthquakes, and they found that earthquakes can cause flooding during high tides by disabling water pumps and knocking down informal barriers.
Hill was encouraged last month when the city and county purchased 1.6 acres nearby to create a much-needed park: They spent $3.35 million with the help of private partners like the Canal Alliance. The city will explore the idea of building a pedestrian bridge within the park to better connect the neighborhood to the rest of the city.
Hills students envision using the new space and other existing parks as emergency centers and to store tents and other supplies, she said.
Hill’s students suggested that if the roads were raised, they could be converted into levees when more protection is needed from rising sea levels.
Hill said the city and county must build more low-income housing in less vulnerable areas for the region’s workforce but don’t have to abandon the Canal Zone. Buildings in flood zones could be redesigned to have first floors with flood protection, as Humboldt County does, or to float, as in the Netherlands, she said.
University of Arkansas associate professor Kevin Befus collects water samples from San Rafael Creek on Dec. 6 during a spring tide event organized by the San Rafael Canal Alliance. (Yalonda M. James/SF Chronicle)
But there are many other places along Marin County’s Gulf Coast that need protection, said Michael Wara, director of Stanford University’s Climate and Energy Policy Program and a Marin County resident.
“The only solution will involve really intensive engineering,” he said. “There are places where Marin has money to defend, and there are places where Marin can’t.”
The Canal Zone is within the jurisdiction of the city of San Rafael, so the city is responsible for raising funds, but the county can propose initiatives when applying for state and federal funding — though the latter has been scarce recently, making it more competitive to get state funds, said Talia Smith, interim deputy county manager.
Smith said the county is working to develop a more unified approach to the problem for the eight jurisdictions along the county’s Gulf Coast, including unincorporated areas, similar to San Mateo County’s OneShoreline organization.
That way, she said, “we’re not pitting the county against San Rafael.”
This article was originally published on Bay Area communities most vulnerable to sea level rise are also sinking: ‘The question now’.
