Belvedere faces sea-rise issues head-on
The city, once an island, has made several changes that could help prevent it from becoming one again
Editor’s note: This article, the second of a two-part series, first appeared in the May 10, 2017, edition of The Ark. It earned second place for In-Depth Reporting in the California Newspaper Publishers Association’s 2017 California Journalism Awards contest.
By MATTHEW HOSE
mhose@thearknewspaper.com
PART 2 of 2 — Belvedere has a unique relationship to the water that surrounds it.
“Water is an integral part of Belvedere’s existence,” says Claire McAuliffe, a city councilmember. “We play on the water, we live on the water — we love the water.”
But in the coming decades, Belvedere will have to decide what to do to keep the water out.
Click to read Part 1 of 2: ‘Slow-moving emergency’
A new report finds that 85 years of sea-level rise combined with a massive, 100-year storm could inundate a Marin-high 36 percent of Belvedere’s parcels, cause $514 million in damage, cut off emergency services to the city and make Belvedere Island a true island once again.
The draft report, called the Marin Bay Shoreline Sea-Level Rise Vulnerability Assessment, describes sea-level rise as a “slow-moving emergency” and contextualizes existing data by describing the vast array of Marin residences, services and resources that could be affected by sea-level rise in 15 years, by mid-century and by the end of the century.
It is part of Marin’s Bay Waterfront Adaptation and Vulnerability Evaluation, or BayWAVE program, which began in 2015 with funding from the county and a $250,000 grant from the California Coastal Conservancy.
McAuliffe, who was one of the first county leaders to push for the sea-level report, says it is an early effort to raise awareness about the complexity of the problem and get conversations started about potential solutions.
“It’s a very complex problem, and it’s going to involve judgments.”
According to Chris Choo, the project manager for BayWAVE, Belvedere provides one of the best examples in the county of how cities should be preparing for sea-level rise in the future.
The lagoon’s game of floods
In Marin County’s national-award-winning “Game of Floods” board game, players are presented with a fictional island facing difficult choices due to sea-level rise. With a limited budget, players must choose between mitigation strategies like using pumps, seawalls and natural barriers like marshlands to save the island’s coast, while enacting policy changes to save as much of the property and people on the island as possible.
In many ways, the Belvedere Lagoon has been playing the game of floods for decades.
The lagoon is where the city stands to lose the most due to climate change, as numerous low-lying homes abut the basin that takes in storm-water runoff from Tiburon hills and, at times, saltwater from the ocean, with only the northern riprap along San Rafael Avenue and the southern seawall along Beach Road to protect it. Those roads also serve as the rest of Belvedere’s only connector to the rest of the Tiburon Peninsula.
The sea-level report predicts that portions of San Rafael Avenue could be flooded in a worst-case scenario in 15 years, 10 inches of sea-level rise combined with a 100-year storm.
By mid-century, the majority of lagoon homes — particularly on the man-made peninsulas like Windward and Peninsula roads — could then flood in a worst-case scenario of 20 inches of sea-level rise combined with a 100-year storm. In the long-term worst-case scenario, the rest of the lagoon could flood under 60 inches of sea rise.
The data has flaws, including an assumption that the lagoon’s tide gates are stuck open. Additionally, those worst-case predictions assume Belvedere doesn’t do anything in the meantime to mitigate the city’s vulnerability.
Whether it has had sea rise in mind or not, Belvedere has made a number of proactive moves on the lagoon that have made it a model for other areas in managing flood risk with a limited budget, Choo says.
“(Belvedere) is a great lesson in what can happen if a community comes together and comes to decide what they want, and it should be highlighted as a success story in Marin in what you can do,” Choo says.
The city got its first wake-up call after winter storms in 1982 overtopped the seawall on San Rafael Avenue and flooded several homes on the lagoon.
Tom Cromwell, the city’s disaster-preparedness liaison, says he was working as a volunteer firefighter at the time and tried to bring an engine up Tiburon Boulevard to get to San Rafael Avenue.
“We could not even find San Rafael Avenue. It was a sheet of water that went from Richardson Bay over San Rafael Avenue into the lagoon,” Cromwell says. “That scared people, and it should have, because you couldn’t transgress it (and) the only way out was by Beach Road. Then what if something happens on Beach Road?”
After that incident, Belvedere raised the height of the riprap, and there “hasn’t been a problem since then” with wave overtopping, says Glenn Isaacson, a board member of the Belvedere Lagoon Property Owners Association.
John Carapiet, the president of that association, says sea-level rise is just one consideration that the lagoon takes into account to protect homes there. It also has to worry about runoff from the Tiburon hillsides, maintaining its pumps and monitoring the level of lagoon water using the tide gate under San Rafael Avenue, which allows salt water in and out.
In 2000, the city built a stormwater-diversion system, making it so that much of the water coming down the hills of Tiburon would be diverted into Richardson Bay rather than the lagoon.
And just a few years ago, the property owners association completed installation of a new pump that can move out 10,000 gallons of water per minute. It also raised all of the electrical boxes and the electricity source for the pump to account for higher sea levels, according to Carapiet.
“We’ve made quite a bit of forward progress here,” Carapiet says. “Even if the sea levels were higher at high tide, we can absorb quite a bit of water. We’re in pretty good shape.”
He says the lagoon got 90 inches of rainwater in the past year in one of the rainiest seasons on record and still maintained the lagoon without incident.
Most importantly, in 2009 the Federal Emergency Management Agency put the lagoon in a federal flood zone, finding that massive storms could inundate homes there.
That led to new rules that any homeowners who do remodels worth more than 50 percent of the value of the home or who do new construction must raise the lowest livable portion of the home above the base flood elevation of 11 feet above sea level.
The rules don’t factor in future projections for sea rise, according to FEMA officials, but policy changes align closely with what cities could have to do when confronted with it.
For one, the new flood-zone rules prompted officials to have a painful discussion about raising the heights of homes on the lagoon, where one-story cottages have historically prevailed.
The city ultimately increased the allowable height of lagoon homes to a maximum of 29 feet from grade from a previous maximum of 26 feet, and it increased maximum fence heights from 6 feet to 8 feet to accompany those changes. Since then, several raised, two-story homes have sprouted on the lagoon.
“The experience with the height limits of the lagoon was sort of a shot across the bow here that changes are coming,” McAuliffe says.
Choo says that the city’s confronting the flood maps head-on with policy changes, along with its proactivity in procuring $611,000 from the state’s Department of Water Resources to study the riprap on San Rafael Avenue and the seawall on Beach Road, pulled people together to begin having difficult discussions about changes.
The biggest discussion of all, according to McAuliffe, will come when the studies of Beach Road and San Rafael Avenue have been finished, and the city could be faced with costly repairs, or, ultimately, the possibility of raising them.
Cromwell says a number of other options could later be on the table, including potentially dredging the lagoon to increase its volume.
But Cromwell cautioned that the city should continue monitoring the progress of sea-level rise to decide later what would be the best courses of action.
“We know it’s going up,” Cromwell says. “The biggest question now is how fast it’s going up, and can we as a society change that rate of rise?”
Cromwell advised against building protections against the “doomsday scenario” unless it becomes evident that is what’s happening.
“If you hold that out to society to say we have to fix things that could happen, that would probably bankrupt us,” Cromwell says.
Isaacson agrees and says it’s difficult to know right now exactly what will be needed in the future. In particular, he expressed frustration with the numbers in the report, which provide a broad range of possibilities for sea-level rise. The assessment acknowledges that the National Research Council’s end-of-century projections range between 16.6 inches to 65.8 inches of sea-level rise, while the county’s assessment chooses a figure on the high end, at 60 inches, or 5 feet of rise, for its long-term scenario. A secondary long-term scenario then adds a 100-year storm surge.
“These ranges are so large that in some sense it’s hard to get your mind around it,” Isaacson says. “If you’re at the lower end of these scales, you have a manageable problem. If you’re at the higher end plus storm surge, you’re at an impossibility to deal with.”
“It puts decision-makers in a bit of a dilemma, what to really plan for and what to really prevent.”
But Isaacson says the report reinforces what has been a known long-term problem for the lagoon.
“The study is clearly a reinforcement of the notion that sea-level rise, if it’s of the magnitude forecast, will have serious implications for the low-lying properties of Belvedere.”
However, Choo underscored that it isn’t just low-lying parts of Marin that are at risk, but that sea rise could indirectly affect everyone.
“A lot of times when you start looking at a whole community, it becomes a lot more challenging, because it does impact those people who are all the way up at the top of the hill,” Choo says.
Against the water
The report takes a holistic look at the different transportation infrastructure, utilities, emergency services and cultural resources that could be affected by sea-level rise. Among other findings, low-lying sewer districts that serve all of Belvedere could be some of the first areas to flood, while utility pipes under roads would “face compounding pressure forces from water and the road,” and road blockages of the two main entrances to Belvedere, San Rafael Avenue to the north and Beach Road to the south, would prohibit fire and emergency services from reaching the city.
“In time, several additional roads in the lagoon area could be impacted by high tides on a regular basis,” the report notes. “If the low-lying roads are compromised, people who live in the homes on Belvedere Island could become isolated or prevented through-travel for several hours several days a month.”
In the long-term, the Belvedere Community Center and Police Department, along with the Public Works corporation yard, could be at risk.
Other parts of the city could face the effects of sea rise even sooner than the lagoon.
A large portion of West Shore Road, along with several historic buildings like the China Cabin and the Farr Cottages that run on the bay side of the Beach Road seawall, could be vulnerable to effects of sea-level rise in as little as 15 years, according to the report. The report notes that the San Francisco Yacht Club could possibly “need to make adjustments or relocate” its marina.
Alan Brune, the executive director of the Belvedere-Tiburon Landmarks Society, which oversees the China Cabin, says the society hasn’t formally discussed the report, but he noted there have been informal discussions including the idea of “launching the China Cabin again” by putting it on pilings that would allow it to move up and down with the tides within a certain range.
He says he put the report on the agenda for the Landmarks Society’s May board meeting.
With a 100-year storm surge, the report projects that the entirety of West Shore Road, the San Francisco Yacht Club and the Corinthian Yacht Club would become vulnerable in 15 years.
McAuliffe noted that those unprotected portions of the city put Belvedere in a unique situation.
“When you think about Belvedere, many of us are hard up against the water,” McAuliffe says.
Fred Gellert is one of those people. The owner of 93 West Shore Road for 43 years says he and his wife, Annette, are keenly aware of the danger of climate change and the threats it poses.
“We’re convinced it’s a phenomenon that’s slowly taking place,” Gellert says. “Just how it’s going to affect us directly is just hard to say.”
But Gellert says that even before sea rise was in his mind, he knew he had been taking on a risk living where he does.
“In the long run, if the water situation became worse and worse, it could affect our property values. But that’s a long way down the road. I’m not losing any sleep about it. None at all.”
“It’s an interesting place to live, right over the water like we are,” Gellert says. “It’s unique. You take the good with the bad.”
Reporter Matthew Hose covers the city of Belvedere, as well as crime, courts and public safety issues on the Tiburon Peninsula. Reach him at 415–944–4627 and on Twitter at @matt_hose.
Click to read Part 1 of 2: ‘Slow-moving emergency’
