Kristina Hill grew up in Worcester, Massachusetts, during the Rust Belt’s decline, which was marked by “closed factories and limited opportunities.” Today, as an expert in urban design and landscape architecture, she sees abundant opportunities for reinvigoration — if we understand that in cities, buildings, and landscapes comprise an urban ecosystem. As an associate professor of urban design and landscape architecture at the University of California, Berkeley, Hill champions retrofitting existing buildings for greater energy and cooling efficiency and for water storage on roofs or in basements. She supports modifying landscapes and buildings together so that cities can address both climate and energy adaptation. Her research focuses on the relationship between groundwater and sea level rise, and she is a member of California’s Sea Level Rise Taskforce.

Big, mechanical solutions are really rarely appropriate: Kristina Hill.

Hill’s training in geology enables her to explain how water is a dynamic natural element as it moves through soils and sand. A veteran of many international projects, these days she consults on sea level rise in marginalized communities at home in the United States. Her work as an intermediary between local governments and environmental justice activists helps them understand the science behind the flooding that low-lying communities will inevitably face. Hill works to promote voices outside of academia that are on the frontlines of rising water. “I’m comfortable talking about technical issues and adaptation strategies” she says, “but I also think lived experience matters.” Last year, for example, she warned the Richmond, California city council that building shoreline condominiums on contaminated soil could expose residents to volatile organic compounds entering their indoor air when sewer lines back up due to rising groundwater.

As cities face multiple environmental problems, Hill wants to see urban planners and designers at the forefront of local government decision-making. “I know we care about all those things: plants, people, animals, the money,” she says. “I think landscape architecture has a unique role to play in keeping things real.” Hill spoke with Earth Island Journal recently about the importance of groundwater, the power of dirt, and the ways that urban design lets policy embody science.

What should coastal cities know about sea level rise?

Most of what we know how to do in coastal engineering is really informed by a long history of dealing with temporary high water. What we’re talking about now is permanently higher water. Sea level is rising at a speed that we haven’t seen for about 7,000 years, since the very first seawall was built on the edge of the Mediterranean in the Stone Age. We don’t know the difference between permanently higher sea levels and temporary high water. Things like levees don’t function with permanent high water because water seeps under and around the levees, and groundwater comes up to the surface behind the levee. So, we have a lot to learn about what it’s like to live potentially below sea level.

The Dutch spent about 1,000 years trying to keep the water out. As they pumped the wet soil behind the dike, the soil collapsed, it sank. They ended up with about half their country below sea level. The same thing happened in New Orleans. When they pumped the wet soils behind the levees, that part of the city sank up to five, six, seven feet. Once that soil sinks, that elevation is gone forever. We have to think about permanent high water and learn from what the Dutch are doing now, which is what they call “living with water.”

What will rising groundwater mean for coastal areas?

What geologists call “unconfined groundwater” rises in the soil, and it comes from rain. It’s being stored in the soil on its way to the ocean or to a river. As the ocean rises, it’s going to push that less dense freshwater up higher. As that freshwater rises, first it will encounter things that are buried in the soil, like sanitary and storm sewers under the street. And if the water rises, the pressure on foundations and on pipes increases.

Our underground structures aren’t really designed for this new pressure. Some of them will heave or shift. Water will make its way into any cracked joints in underground pipes. People will start to see backups in sanitary sewers into and under homes and businesses and schools. Storm drains won’t carry water away. Under certain conditions of high tides, groundwater will come up and out those pipes. Any pollution in the soil from old dry-cleaning facilities, or gas stations, or military bases, or chemical factories will be affected by rising groundwater. Contaminants, like benzene with a gas component, can enter sewer pipes and enter people’s homes, and not be detected until it’s too late and you’ve been exposed for years to a cancer-causing chemical. Somebody’s going to pay the price, or someone’s children, unless we are ready for how the underground world is changing as the sea rises.

How does landscape design act as the intermediary between science and policy?

Design is what allows science to be embodied in policy. If we know that urban heat islands are a real problem — and we know that from science — policy could say, “Well, let’s cool the city,” and then design would help us figure out how to do that in a way that provides other benefits, like parks, and shady bus stops, and shady schoolyards.

Design, meaning architecture, landscape architecture, urban design, civil engineering, these all need to be part of that conversation between science and policy. Otherwise, we just keep making the same mistakes over and over again, [building] houses that are expensive to cool, streets that aren’t multifunctional. We don’t think about a new prototype, a new way to do it, until we involve design in that conversation. Scientists have been telling people what’s going to happen. How high the sea will rise. Rivers will spread out more, and groundwater will rise. The first thing that scientists will say is, “Well, people are going to have to retreat from the shoreline.” From a design perspective, sometimes that’s true, sometimes it’s not true.

We could live like the Dutch, especially around the San Francisco Bay Area. We can move dirt around to live with that higher water and not retreat. If you live in Pacifica on the edge of a bluff, there is no solution that’s going to keep that bluff in place when the waves chew away at the bottom of the cliff. That building is going to fall. No design strategy for that. But for the edge of the San Francisco Bay, if you think differently about how to move dirt around and think about a world where you live with higher water, we can absolutely not retreat. The whole word “retreat,” it’s got a negative connotation. What we have to think about is how to adapt.

In London, Rotterdam, and New Orleans, levees and huge mechanical solutions control flooding. Are these types of coastal defense systems the best solution to control water?

I think that the big mechanical solutions are really rarely appropriate. They’re appropriate in places like Rotterdam, the biggest port in Western Europe. Their whole economy depends on that shipping port. Even London. It’s not shipping, but it’s protecting Central London’s financial district, which is their economy, from flooding. Those big mechanical systems are a kind of spectacle that sells engineering and promotes the idea that that city is technologically advanced. Most cities should be taking a different approach, which is moving dirt around. Otherwise, our children, their children, will be stuck with these monstrosities. They’ll be paying the debt for the construction of those structures. Where if we used dirt, lowly, common dirt, we could build mounds, ponds, levees, beaches that would actually be legacies, not liabilities, for future generations.

Anything can be overwhelmed as things continue to change over time. We have to plan for two feet of sea level rise, or three feet of sea level rise. Then that phase will have to end, and we move that whole strategy a little bit inland and return those ponds or mounds or levees to tidal marshes. And luckily, if we’ve dug a pond, we can fill it in with the material we cut for the new pond. So it’s a kind of self-sustaining strategy, where you always have the material that you need to do the next phase.

What can we learn from the Japanese and the Dutch about climate solutions that are equitable and resilient?

The biggest thing that we need to learn is that when you build a wall, whether it’s made of dirt or made of concrete and steel, there’s a risk of brittle failure. Catastrophic failure. To live behind a wall is to always be at risk of a sudden catastrophe that you can’t evacuate from. The Dutch and the Americans are looking at Japan because they’ve developed this super-dike. It’s like three times wider, a quarter of a mile sometimes. On the backside, it has terraces, so that if water ever comes over the top, it is slowed down as it makes its ways to the lowest, flattest, most vulnerable houses. The structure behaves like a geologic feature, a big topographic ridge, instead of a narrow floodwall or a dike like we see in the Sacramento River Valley, the California Delta. They can be overtopped, but they don’t break. And there isn’t a sudden flood that would drown people. That’s the kind of thing we need to all learn.

In Rotterdam they dug a shallow pond, then built luxury homes on wooden pilings, and that pond now serves as a stormwater detention pond. It’s like the rich people helped pay for public infrastructure that protects the lower-income people, which is the kind of Robin Hood story that I think is terrific in climate adaptation. Rich people get to live in beautiful homes on the water. And the people with less money get to continue to live in the older homes and keep their neighborhoods intact.

How can we get urban planners and policy makers to take the idea of adaption seriously?

The hard part is that people are still minimizing the magnitude of what’s coming. The airports in Oakland and San Francisco are building dikes around the runways. But there’s a limit to how high they can be because airplanes have to land over them. As the ocean keeps rising and the groundwater under the airport keeps rising, they have to pump more and more, and the runways will start to subside. So land is actually going down at the same time the dikes are going up. Adaptation requires you to look at things in a different way. You have to think of a different kind of runway.

The Japanese built the prototype, full scale, for a floating airport runway called Mega-Float in the early 2000s. They’ve tested something that’s a good strategy for what our airports could use. We need to start doing the same thing.

What happens in California matters nationally. Can we point the way to a more forward-thinking climate agenda that includes justice and equity?

There are lots of ways in which cities are sort of oases in a changing climate. If we distributed the burdens of pollution more equitably, people wouldn’t be as exposed to acute pollution. And if we organize our cities so that we aren’t as exposed to pollution, then being in a dense place has a lot of advantages that can be really healing, especially if we find ways to use land trusts and different models of land ownership or building ownership to turn our cities into communities, instead of a kind of Survivor game.

“I look for partners, so that I can come in and share some information that helps them find a workable solution. I can’t do anything without them.”

We have one of the highest degrees of income inequality in the nation. If we partnered with other states, we might learn more. Even states that you’d think politically you might not have as much in common with. Louisiana is building a lot of wetland. Charleston, South Carolina, is doing a lot of urban adaptation to flooding. Our politicians always need to sound like [California’s economy is] excellent and booming. But a lot of it depends on things we need to stop doing. Like oil and gas extraction, or refining.

Until we really start making change in how we build new buildings, how we retrofit old buildings, what our industries are, I think other states, like Massachusetts or Washington, may move ahead faster. All we have to do is start doing pilot projects. But some of our efforts to try new things are limited by old ways of thinking about the environment. Like: You can’t put a floating hot dog stand in the Aquatic Park in Berkeley because it might hurt a fish. Maybe calling things temporary is the way. A hot dog stand that’s only there for a week. If we would just start trying those things, I would have more confidence that California can be a leader.

You see yourself as an activist as much as an academic. What does that mean for your work in low-income coastal neighborhoods around sea level rise?

I look for places where there’s already energy being put into helping the neighborhood become more livable. In East Oakland, Marquita Price at East Oakland Collective and Margaret Gordon from the West Oakland Environmental Indicators Project are already putting blood, sweat, and tears — and have for decades — into change. I look for partners, so that I can come in and share some information that helps them find a workable solution. I can’t do anything without them. And, frankly, public agencies shouldn’t do things without them. Everyone needs to work with local activists because they know the immediate needs of those communities. That’s where we’re going to get positive change to happen.

This article has been edited for clarity and length.