Locals Plan to Hold Back Sea Level Rise
This story originally aired on KALW-FM.
I’m on the east side of Alameda Island, standing in mud in front of a storm drain that empties out into San Leandro Bay. There’s a stretch of homes right on the shoreline looking out at estuaries, the Oakland Airport, and Coliseum. The waterline isn’t quite at my feet right now, but in less than a century I’d likely be standing in water up to my shoulders.
"Definitely the kind of thing where you could have a kayak out here, walk out of your house, walk a few feet down, throw it in the water, and paddle off in San Leandro Bay," says John Knox White as he looks out at the street in front of his home.
White sits on the Alameda Planning Board. He lives three blocks from the eastern shore that is expected to be inundated with water by the year 2100.
"That’s the glorious vision of it, right? Waterfront property for everybody. Yay!" he says, sarcastically. "But unfortunately it also means all the houses due east of me are sitting in water."
Kristina Hill, professor at the College of Environmental Design at UC Berkeley, says, "Sea level rise has been happening since the glaciers melted. So it’s been coming on for 20,000 years."
At the end of the last ice age, global oceans rose about 40 feet. Since then, there have been periodic surges of rapid sea-level rise from glacial melting. Hill says the rate’s been getting higher in the last 100 years, and that will make matters worse for Bay Area cities already feeling the threat.
Foster City, for example, used to be tidal marshlands. Now, it pumps water out of its lagoons to keep the levels low. Marin City dealt with floods after seven feet of king tides submerged roadways in 2012. And in Alameda?
Protecting the south shore
"We’re watching it happen all the way around the island," says Linda Weinstock, one of the Island’s 73,000 residents.
"I live out on south shore, and we’ve lost about 12 feet of our shoreline just in the last two years," she says.
In response to the erosion, the city recently dumped tens of thousands of cubic yards of sand there. Hill says over time waves have pushed sand farther out, creating an edge on the Island that ends up reducing the momentum of waves.
"Anybody that’s been to Crown Beach at low tide knows you can walk pretty far out," she says. "That sand has moved away from the beach and is shallowing that whole part of the Bay between those two areas on the coast, and that’s reducing the risk of flooding." She says it’s one protective measure utilizing the shape of the land, beaches, and marshes. But if nothing else is done, much of this area remains at risk.
The southwest front
On the southwest shore at Alameda Point is a spot called Seaplane Lagoon. Out in the water, seagulls swarm around a harbor seal as it thrashes around a stingray. Richard Bangert is capturing it all on camera. He’s a blogger for the Alameda Point Environmental Report and comes out here at least twice a week to observe the wildlife.
"There have been over 180 species of birds recorded at Alameda Point over the past decade," he says.
Bangert is standing on the former Naval Air Station — about 10 acres of pavement with old, unused buildings. Like the eastern shoreline, Alameda Point is expected to be under four feet of water by the year 2100 if nothing is done to protect it. Unlike the eastern shoreline, the city does have a plan for protecting this area.
"A better environmental use of this area would be to remove the pavement, remove the building and make it part of that wetland area," says Bangert.
Wetlands would provide a buffer from sea level rise and storm surges. And wetlands reduce erosion. The area around Seaplane Lagoon is actually slated for tidal wetland development in the Alameda Point Master Infrastructure Plan. The plan outlines the city’s vision to build a mixed-use development that will include about 1,400 new homes. It also includes other strategies for protecting the Point from sea rise.
"There’s essentially raising the grade which is fill — importing dirt to raise the level of the ground, so that the new development is essentially outside of the 100-year-flood zone plus 18-24 inches of sea level rise," says Jennifer Ott, the city’s chief operating officer for Alameda Point.
"We need private investment to help us implement the flood protection measures that we’re planning out here," she says.
To pay for the estimated $600 million infrastructure project, says Ott, the city will also pursue state and federal funding and eventually collect from future property owners.
But Professor Kristina Hill says we really need to be thinking long-term beyond Alameda Point’s two foot protection plan.
"It is only going to work for another 25 to 30 years," she says. "Those buildings are being designed to be there for 100 years. We need to have the protections, the infrastructure to also be good for 100 years. Otherwise, our tax dollars will have to be used to protect those new expensive developments 25 years from now. That doesn’t seem fair."
Alameda Point is one location where the city has a plan. But the forecast for rising tides combined with a major storm could put more than half of the island’s residents at risk. And that’s just one coastal community of many in the Bay Area that will have to face the reality of sea level rise.
Laura Flynn is a freelance reporter for KALW-FM.