Flood safety and clean water in Vermont: Natural, lasting solutions
6 min read / July 31, 2023
6 min read / July 31, 2023
Rushing water can destroy buildings, damage roads, and scour topsoil. Slower water has less destructive power; everything from sand grains to tree trunks can drop out of the current. Floodplains hold water during floods and help streams and rivers take a slower, meandering course. Beaver wetlands and fallen trees also slow water.
During heavy rain, the fine roots and rootlike structures of fungi, plants and trees along rivers and streams filter excess nutrients, such as phosphorous and nitrogen, by taking them up into their roots. Floodplains and wetlands can also detoxify and help break down some other pollutants that may end up in water. This helps keep water clean.
Upland forests—full of tall trees, moss, and fallen wood—absorb water and keep it from rushing downhill. Floodplains and wetlands help water—and what the water carries— absorb into the earth. Soil particles and excess nutrients from fertilizers used on farms and lawns settle out of slow-moving water and return to soil in the floodplain.
Healthy floodplains and wetlands are incredibly biodiverse places. Wetland plants support wildlife from mayflies to moose, trout to thrushes, wood turtles to warblers. Fish and amphibians breed in shady pools, birds nest on sandy banks, otters play, and beavers create wetlands that grow the shrubs they love to eat.
In the 1960s a dam was built on the Button farm in Colchester. It created a small pond near a dairy barn.
Many decades later, with the cows gone, the dam was causing erosion due to a failing culvert. It was also keeping water from reaching its natural floodplain downstream. In summer, the pond’s warm, stagnant water was full of algae that blocked light and oxygen, limiting aquatic life.
The dam was removed and a healthy stream valley is where the pond once was.
We designed a new creek bed that gave the creek room to fill and move. We also added dead wood as well as hundreds of live trees and shrubs to create a natural environment.
Today, the creek responds to storms by rising and filling its floodplain, helping replenish the creek valley and supporting clean water. Many birds, amphibians, mammals, and insects are thriving here.See story and videos
Healthy rivers move around their floodplains; they will curve into tight bends in some areas and straighten out in others. In places where rivers and streams meet up (called a confluence) even more space is needed because of the increase in water volume.
For the past few centuries, people tried to control river movement by adding rock to riverbanks. While this might protect fields, roads, or buildings, in the short term, over time this can cause erosion in other areas. It increases the risk of the river bursting its channel in a destructive way that impedes flood safety.
Mill Brook flows into the Winooski River at Jericho Settlers Farm in Jericho. Earlier farmers and the federal government had placed rocks along the banks on the brook and river. Because of this, the brook eroded several acres of farmland after big storms in the early 2010s. The field was no longer a good place to farm.
We worked with the farmers to devise a solution that helped the river and the farm. Grant funding for a floodplain protection easement compensated the farmers for fields they were giving up. The easement means that this confluence will never be constrained.
To give the restoration a head start, volunteers planted 1,000 trees that will eventually grow into floodplain forest.
During the floods of July 2023, the fields filled with water and stored and slowed floodwater for several days. With more intense storms from climate change, these natural solutions are becoming more important than ever.Read news story
Wetlands aren’t great places to farm, and farmers tend to stay out of them. But in the past, farmers would sometimes drain wetlands to convert the land to farm fields. When this happens, the water the wetland used to store moves quickly away—especially during big storms—often rushing into nearby streams loaded with sediment and nutrients.
Decades ago, on a farm along the Missisquoi River in Sheldon, a ditch was dug to drain a wetland, but the resulting field was still very wet and hard to farm.
We worked with the farmer to restore the wetland and place a conservation easement on the land that protects the nearby river. Grant funding for the easement compensated the farmer for the farmland lost because of the restoration of the wetland.
We worked with engineers, contractors, and our partner, the Missisquoi River Basin Association, to lower the level of the land, plug the ditch, and plant trees, shrubs, and other plants that are happy to grow in wetlands.
This new wetland supports clean water. It stores and filters water that would otherwise rush into the river after heavy storms. Deer, dragonflies, songbirds, and frogs are just some of the animals we’ve seen using the restored wetland.Read full story
A river likes to be free to move around as it wants, just like people do. Nothing makes a river happier than being able to meander through its natural floodplain (the flat land right next to it).
Meandering rivers have slower, less damaging currents and contribute to flood safety. And, rivers that spread their water across a floodplain become less destructive when there’s a lot of rain or snow melt. The floodwater held by a floodplain is water not rushing through communities down river.
Since floodplains are flat and fertile, they are often home to farms. But moving rivers can challenge farmers who invest in their fields. To address this, we work with willing farmers to get funding for conservation measures that give the rivers their freedom and compensate the farmer for giving up total control of the land.
Valley Dream Farm in Cambridge is an example of this work in action. Farmers Joe and Anne Tisbert protected 64 acres with floodplains, wetlands, streams, plus 1.5 miles of the Seymour River (pictured), which flows into the Lamoille. We were able to get state funding to compensate Joe and Anne for the land they lost from farming.
Protecting rivers in this way can be a win-win for both farmers and rivers, and everyone that depends on them.Read full story