Vermont flood costs could exceed $5.2 billion

Homeowners and low-income households to be disproportionately impacted by increased flooding, UVM study says

Property damages from flooding in Vermont are calculated to exceed $5.2 billion over the next 100 years, new University of Vermont research finds. 

The most flood damages are projected along the Winooski River floodplains, which houses many of the state’s most populous towns, including Burlington, Essex, Colchester, Williston and Montpelier.  

The findings result from a new tool developed by UVM scientists that provides the first ever comprehensive map of flood risks across Vermont’s Lake Champlain basin.  

“This new flood mapping tool is critical for risk management, particularly given rising flood risks due to climate change,” says Beverley Wemple of UVM’s Geography Department and the Gund Institute for Environment. 

The UVM-made tool reveals greater flood hazards, in more detail, than existing state flood maps. Using next-generation technology and public data, the researchers analyzed eight levels of flood probability, ranging from smaller floods that occur every 1-2 years to more destructive 50-, 100- and 500-year floods. 

The study calculates flood damages at $2.13 billion at current conditions. However, that price tag jumps significantly—to $5.29 billion—when climate change projections for Vermont are factored in over the next century.  

The research, published in the journal People and Nature, is among the first to directly link flood damages to individual properties with climate change and floodplain restoration. The results build on the recent Vermont Climate Assessment, which found rising flood risks. 

The team hopes the findings will help prepare Vermonters for greater flooding, show the urgent need for floodplain investments, and help those impacted most by flood events.  

Flood impacts 

The results show that homeowners are expected to be hit harder by flooding than commercial owners, with lower-income households hit the hardest. 

“This research shows that the Vermonters least able to prepare and recover from flood damages disproportionally face the greatest threat,” says UVM lead author Jesse Gourevitch.  

Low-income households are more likely to live in homes less resistant to flooding, and have less savings and insurance coverage.  

The researchers calculated damages by major watershed, property type, and socio-economic group, rather than individual towns. They identified key properties repeatedly inundated by flooding, which require greater flood protections or could be purchased and converted into floodplains. 

“Smaller towns and municipalities will soon be able to access up-to-date flood hazard data that may be too expensive to create on their own,” says study co-author Rebecca Diehl of UVM, noting the tool could help other states and regions. 

A natural solution for flooding

The team recommends restoring key state floodplains, which they calculate have the potential to reduce flood-related damages by 20%.  

Floodplains absorb flood waters and reduce the amount and speed of water that reaches communities. Restoration efforts include reshaping riverbanks, restoring wetlands, and adding vegetation. 

“We need to think about floodplains as green infrastructure,” says Taylor Ricketts of UVM’s Gund Institute for Environment and Rubenstein School of Environment and Natural Resources. “Floodplains and wetlands can help protect our communities from flood damages. As climate change brings more frequent and severe storms, the value of these natural assets will only increase.” 

Floodplains also provide a range of additional benefits, including improved water quality and habitats for wildlife and outdoor recreation. 

Phosphorus filter

The scientists are also exploring how floodplains can help address Vermont’s phosphorus problem.  

The team created a first of its kind dataset in Vermont, based on their extensive fieldwork, showing that floodplains can keep hefty amounts of phosphorus—from one to 30 pounds per acre—on land and out of waterways. 

The scholars are working with Vermont’s Functioning Floodplain Initiative, collaborating with UVM lead Kristen Underwood, the Vermont Department of Environmental Conservation, The Nature Conservancy, and the USGS Water Center, and others. Their updated flood maps and data will be available later in 2022 through the Functioning Floodplain Initiative.  

The research was made possible by funding from the National Science Foundation to Vermont EPSCoR, the USDA McIntire-Stennis program, the Lake Champlain Basin Program, and The Nature Conservancy in Vermont.