Landscapes constantly change over time. Nowhere is that more evident than in a floodplain, a place where land and water come together to actively reshape the environment. But when humans decide to build a permanent town on the dynamic floodplain, the result can be devastating floods like the 2011 Susquehanna River flood in New York State when the river rose 21 feet in 24 hours, swamping towns along its course.
“Floodplains are not defined by land or water but by the interface between the two,” says Jamie L. Vanucchi, Landscape Architecture. “Every time we remove an acre of forest or construct a new house, the so-called boundaries of the floodplain shift. They are always changing, but we see them as fixed.”
Part of the problem is that floodplain boundaries are often drawn from maps, created by the Federal Emergency Management Agency (FEMA), based on hydraulic modeling. These maps were meant to designate relative risk, not whether a particular area is inside or outside the floodplain, according to Vanucchi. “And because we have used terms like ‘100-year flood,’ people tend to think these disturbances are few and far between,” she adds. “That’s just not the case, necessarily. Especially with climate change, our flood regimes are changing.”
Flexibility and Synergy of Landscape Design
Vanucchi is interested in the merger of science and design—taking into account natural processes when planning a landscape. “To make landscapes that work well, we need to think about design that acknowledges and works with generative processes that are already present in a landscape,” she says. “We need to understand ecology and science.”
The flexibility and synergy of design can help with science’s shortcomings, Vanucchi says. In particular, science has trouble grappling with the plurality of complex problems and places, whereas design is good at addressing complexities and thinking across disciplines, she points out. And as human-wrought changes to landscapes cause more environmental novelty and uncertainty, design can work with scientists and stakeholders to ask what we value and what kind of future we want. “It’s not about fixing problems; the real power of design is in worldbuilding and speculating new futures,” she says.
“Every time we remove an acre of forest or construct a new house, the so-called boundaries of the floodplain shift.”
In her projects, Vanucchi seeks input from a wide range of stakeholders. In one overarching project centered on the Susquehanna River watershed, she has been reimagining the floodplain as an interface zone. Through what she calls fuzzy floodplain mapping, she describes the floodplain not simply through the hydraulic modeling of FEMA maps, but through multiple lenses that reach far beyond risk alone—including people’s lived experience of floods and the use of fluvial soils as indication of the original extent of the floodplain. “Floodplains are mosaic landscapes for biodiversity, and they can be potent sinks for carbon,” she says. “They should be community assets.”
Living on Floodplain Time
Vanucchi has been talking to residents living along the Susquehanna River about their experiences in the flood of 2011. Many struggled for years to recover, living in what she calls floodplain time, a period after a major flood when time slows down in many ways as homeowners tear apart waterlogged houses and wait for them to dry out. Some homeowners opted for buyouts if their property was substantially damaged. In this process, which can take five to six years, the United States government—or sometimes state or local governments—will offer the homeowner pre-flood value for their home. If the homeowner accepts, their home is demolished and the lot remains forever green.
In the village of Sidney, New York, people hoping for buyouts were living with leaking roofs for years, Vanucchi says. “They didn’t know if they should rebuild their homes because they were waiting for the buyout money to come through,” she explains. “People get stalled in this floodplain time, which the community collectively goes through after a flood. Then, after five or six years, the community mostly recovers. But what will happen when this slow recovery time can’t keep pace with accelerating changes that are coming with climate change?”
Planning for Future Floods
Adapting to climate change requires new ways of thinking about the floodplain, Vanucchi says. For instance, buyout lots are often managed as lawn. The sites were at one time developed, however, and compacted surfaces persist under the grass. “There’s more runoff from buyout lots like this,” she explains. “On the other hand, if you move from compacted lawns to forest, you’re doing a lot to mitigate runoff.”
Vanucchi and her collaborators are also taking a look at the process of elevating homes to avoid flooding. Using flood predictions based on hydraulic modeling, homeowners can elevate their home above the predicted flood height at a cost of approximately $10,000 per foot. Such a high price makes elevation unattainable for many homeowners, and even those who can afford it can be unpleasantly surprised when a flood comes.
“Especially with climate change, margin of error is critical,” Vanucchi says. “For example, a homeowner in Owego, New York, elevated their home long before the 2011 flood and ended up with 18 inches of water in their first floor.”
The researchers want to figure out ways to educate homeowners about the buyout and elevation processes as a way to help address inequities in how people experience flooding and recovery. Vanucchi mentions studies by sociologists James Elliot and Junia Howell, cited by a 2019 National Public Radio investigation. Elliot and Howell revealed that after floods and other disasters, rich people tend to get richer and poor people tend to get poorer. “The disparities also break down by race and by education,” she says. “It is not unusual for these floodplain housing zones to exacerbate inequities that are already present.”
To explore the impact of buyouts, Vanucchi has joined with Linda Shi, City and Regional Planning; Amelia Greiner Safi, senior research associate, Population Medicine and Diagnostic Sciences/Communication; Rebecca Morgenstern Brenner, lecturer, Cornell Institute for Public Affairs; and Christine Shepard, lead scientist at The Nature Conservancy. The researchers are looking at buyout programs in five study areas across the United States in an effort to understand both social and ecological outcomes.
“In the best cases, buyouts become community amenities: trail systems, community gardens, or open spaces,” Vanucchi says. “But what happens there? Does the buyout process address social inequities? What level of restoration is occurring? In what ways are these lots helping to mitigate future floods? And what does that say about the buyout process and program?”
Designing for Carbon Sequestration
Vanucchi is also interested in testing the ability of landscape to mitigate climate change by designing for increased carbon sequestration. Collaborating with departmental colleague Maria Goula, she took part in the 2019 Reimagining the Canals Competition sponsored by the New York State Governor’s Office. For their project, which was a finalist, Vanucchi and Goula looked at abandoned agricultural land along the Erie Canal corridor and asked how it could be put to work sequestering carbon.
“Our aim is to put fallow farmland to work sequestering carbon while also rebuilding the heritage landscape of the canal,” Vanucchi says. “Reforesting wet and underproductive farmlands could also connect forested corridors across the landscape along this critical migratory pathway.”
Rather than a write-off for farmers, as it is now, the land might instead make money for them through a voluntary carbon marketplace. “One of the great things about this is if we construct this forest armature we’ve been thinking about, then it will do so many things we think a landscape can do, like support biodiversity, place identity, and nature-based tourism,” Vanucchi says. “It can rebuild some of the economic loss these communities have seen. And it can anticipate and project future change and help produce collectively preferred futures.”