Parts of San Rafael, a city just north of San Francisco, are sinking about half an inch per year. That might not sound like much, but altogether, it has meant that some neighborhoods — like the Canal District that borders the bay — have sunk three feet, placing them at greater risk of flooding from sea level rise.
San Rafael isn’t alone. Cities around the world are threatened by rising sea levels, with 300 million people at risk of routine flooding by 2050. The cost of building seawalls to hold the waters back could top $400 billion in the U.S. alone.
A new startup is proposing an alternative: raise the city instead.
Terranova is building robots that will inject a slurry of wood waste into the ground, slowly lifting the land to eliminate historical subsidence and, hopefully, prevent those parts of the city from flooding.
“The canal district is really far under sea level,” Laurence Allen, co-founder and CEO of Terranova, told TechCrunch. The city has been working with flood consultants to find a solution, he said.
“The answer, every answer every time, has been like $500 million to $900 million of seawalls, which if you’re from San Rafael, you know they’re not even close to being able to afford that. There’s about 60,000 people and a significant portion — surprisingly for a city in Marin — are living in poverty.”
Terranova says it can protect San Rafael and other cities like it for a fraction of the cost. In San Rafael’s case, the startup has quoted $92 million to lift 240 acres four feet.
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