Certain areas of San Rafael, a city located just north of San Francisco, are subsiding at a rate of about half an inch each year. While that may seem minor, over time it has resulted in neighborhoods—such as the Canal District near the bay—sinking by as much as three feet, making them more vulnerable to flooding as sea levels rise.
San Rafael is not unique in facing this issue. Cities worldwide are dealing with the threat of higher sea levels, putting 300 million people at risk of frequent flooding by 2050. In the United States alone, constructing seawalls to keep the water at bay could cost more than $400 billion.
A new company is offering a different solution: instead of building barriers, why not elevate the city?
Terranova is developing robots designed to inject a mixture made from wood waste into the soil, gradually raising the ground to reverse years of sinking and, ideally, protect these neighborhoods from future flooding.
“The canal district sits well below sea level,” said Laurence Allen, Terranova’s co-founder and CEO, in an interview with TechCrunch. He explained that the city has been consulting with flood experts to find a viable answer.
“Every proposed solution so far has involved building seawalls costing between $500 million and $900 million. If you know San Rafael, you’ll realize that’s far beyond what the city can afford. There are about 60,000 residents, and a surprisingly large number—especially for Marin County—live below the poverty line.”
Terranova claims it can safeguard San Rafael and similar cities for a much lower price. For San Rafael, the company has estimated $92 million to raise 240 acres by four feet.
According to TechCrunch, Terranova has just secured $7 million in seed funding, led by Congruent Ventures and Outlander, with GoAhead Ventures, Gothams, and Ponderosa also participating. The round was oversubscribed and values the company at $25.1 million.
Injecting materials underground to lift land isn’t a new concept. Terranova’s innovation lies in its unique methods that reduce costs.
The first innovation is the use of waste wood, which is both cheap and readily available. The company blends it with undisclosed additives to form a slurry. This mixture is pumped from a 20-foot shipping container to the next cost-saving feature: a robotic injection system. These tracked robots autonomously move around the site, drilling wells and delivering the wood slurry to depths of 40 to 60 feet.
Allen noted that as long as the slurry stays moist underground, the wood should not decompose, allowing the company to generate revenue from carbon credits to help offset expenses.
Terranova manages the entire process with proprietary software. The system uses publicly available geographic data along with information from core samples drilled across California, mostly during water well construction. This data is used to build a subsurface model that guides the injection strategy, which is optimized using a genetic algorithm.
On the software’s backend, planners, contractors, and other stakeholders can use a tool similar to SimCity to design the digital landscape.
Once the plans are set, they direct the robotic injectors on where and how much to inject. Human supervisors remain on site for safety, Allen said. After the robots finish, the slurry takes about two hours to settle, he added.
Allen said Terranova has been running pilot tests of both the robots and the software for over a year.
Some experts have raised concerns that the consolidated wood slurry might worsen earthquake impacts, but Allen pointed out that the more traditional alternatives carry their own risks. “We believe our approach could actually help with earthquakes compared to dikes and seawalls.”
The company’s business model involves sharing project revenues with contractors. Terranova hopes its low costs will make the process appealing for a variety of land-raising projects, including restoring wetlands that are vanishing due to sinking land or rising seas.
However, with the immediate threat of rising water, cities remain Terranova’s main focus. “I grew up in San Rafael,” Allen said. “Saving the city is very important to me.”
