Vermont has long been prone to flooding and flood damage. Centuries of altering rivers by straightening and dredging them has caused many to become disconnected from their floodplains. When heavy rains occur these rivers cannot spill over their banks onto the land to release their energy. Flood flows pick up volume and speed as they flow downhill, putting communities and infrastructure in harm's way.
Changes in Vermont's climate will make the state's historic vulnerability to flooding and erosion greater still. This could create serious risks for public safety and property losses for homeowners and businesses. These high stakes create a compelling reason for Vermonters to work together on building flood resilience by getting better prepared for emergencies, and also by reducing risk through good land use choices and smart building improvements.
After Irene, What's Next?
Tropical Storm Irene still lives vividly in our memories. Most Vermonters know someone whose life was turned upside down. Thirty-five hundred homes were damaged along with more than 500 miles of state roads and 200 bridges. Many farms and businesses were damaged and lost income from suspended operations. The staggering costs to federal and state taxpayers climbed above $800 million. Grasping the extent of the losses in human terms is difficult.
In the on-line newsletter Grist, Kevin Geiger of the Two Rivers Ottauquechee Regional Commission was quoted saying “There are streams that aren’t streams — streams that had no water in them (before the storm) — that split houses in half. You had streams you could step over carrying full-size trees.”
The National Climate Assessment, released by the federal government in 2014, warns that extreme weather events will progressively increase during this century. The northeastern states in particular are projected to get wetter in the winter and spring.
These trends have already been observed in Vermont and in the entire Northeast region. A report from the U.S. Global Change Research Program shows that from 1958 through 2012, the amount of precipitation falling in the most intense 1% of precipitation events increased by 37% in the Midwest and 71% in the Northeast. There is no certainty about whether Vermont will experience another Irene anytime soon (although some meteorologists believe that hurricanes may become more common in inland portions of the northeast). But there is little doubt that Vermont needs to be prepared for intense storms in the future.
We've already seen an uptick in federally declared flood disasters in recent decades. There were 14 in locations across the state between 2005 and 2015.
How Serious is the Risk?
The best way to understand how future flooding might affect Vermont is to cast a glance backwards. More intense storms will fall on watersheds that already have sustained economic costs from repeated flooding. This map showing the locations of federally funded disatser recovery projects in Vermont makes clear that few communities have escaped these costs.
Some of the greatest risks are to infrastructure concentrated near streams and rivers. Drinking water infrastructure and wastewater treatment plants have sustained significant damage during past floods. In the days and weeks after Irene, 13,000 Vermonters had to boil their drinking water. Electric transmission infrastructure was also damaged by the historic erosion and flooding.
How Vulnerable is Your Town?
ANR's Flood Ready Vermont web site contains tools for assessing and printing reports on your town's flood hazards. It also has detailed information on how communities can build resilience, and many success stories about those that have. Easy to use maps of floodplains and river corridors can help towns plan for a future with reduced risk of flooding.