Wetlands and floodplains along Otter Creek protected Middlebury from more than $1.8 million of flood damage during Tropical Storm Irene, according to a new study from the University of Vermont.
These natural buffers act as sponges and absorb excess floodwaters, and they will be even more important as climate change brings more severe weather, says lead researcher Keri Watson of the Gund Institute.
“With climate change, we’re already seeing an increase in the severity and frequency of floods in New England, and globally,” says Watson. “We know that wetlands and floodplains can reduce impacts, but it’s really hard to act on that if don’t know size of that impact.”
Researchers used water level data from upstream and downstream of town to calculate how much more water – and damage — would have struck Middlebury without these natural buffers.
Watson says that the true value of the destruction avoided in Middlebury is actually far greater than $1.8 million.
That’s because “in Vermont, a majority of flood damages actually occur as the result of erosional impacts, and impacts to infrastructure like roads and bridges," she says. "And we couldn’t get at those damages, so the values we present in our study are really conservative for that reason.”
Watson says the study could only evaluate a small portion of avoided damages, which means the protective value of the wetlands is far higher.
Some communities in Vermont face the additional challenge that the rivers and creeks upstream have been straightened over the years, which makes the waters faster and deeper — and disconnects the rivers from their natural sponge buffers, wetlands.
That’s why the Department of Environmental Conservation is working on a river corridor program to allow the rivers to slowly recreate protective floodplains.
“Communities that are benefiting from these wetlands and floodplains are going to be more resilient to climate change, and this is huge challenge we have ahead of us,” says Watson.
She adds: "Protecting these wetlands and floodplains so that they can continue to protect us is extremely important.”