Field Notes

Improving flood resilience through small dam removal

11 min read / October 4, 2024

Jeff Simpson and his late wife, Valerie, bought a property in Dorset, VT that they loved...

…but they also inherited a nearly 200-year-old dam.

Jeff and Valerie valued the history of the aging dam, which was built on their property in 1830 to power a sawmill. But they recognized an opportunity to restore the blocked stream, a headwater tributary of Otter Creek, to its natural state. A small dam removal project would improve Vermont’s wildlife habitat and water quality and reduce the impact of flooding downstream, should the crumbling dam fail during a heavy rainstorm.

VLT helped them develop a plan and obtain funding to remove the dam for good. Learn more in the videos below.

Restoring stream health is a win for all

In the 1830s, hundreds of small dams were built along Vermont streams to help power mills for industry. Now, we’re in a different era. As climate change brings more intense rainstorms and floods to Vermont, these aging dams are easily damaged, increasing the chances of flooding downstream. We can remove these dams and restore stream health to improve biodiversity and reduce the impacts of flooding in our watersheds.

In August, VLT broke ground on a project to remove Jeff and Valerie’s dam with funding support from Watersheds United Vermont. Our partners included engineering firm Fitzgerald Environmental Associates and construction crew Ameden Construction. As more of these projects take shape, we can make a positive impact on watershed resilience to flooding and climate change.

Learn more about the small dam removal process and watch the deconstruction unfold in this video series featuring VLT ecologist, Allaire Diamond.

First step: Removing the sediment

On Day One of the dam removal project, Allaire reviewed the reasons for removing aging dams. Then it was time to start the deconstruction process. The first step? Removing all the muck that had built up behind the dam wall! The sediment had accumulated for far too long to be washed downstream without damaging the ecosystem. We moved it to a nearby field, where it is now held in place by plants and grass.

Next step: Removing the dam

The dam was removed piece by piece (along with old railroad ties and even some broken pottery!). Then our construction crew rebuilt the streambed with a natural gravel bottom. We also created floodplain benches that will allow the stream to expand during storms to prevent excessive flooding downstream.

Step three: Restoring the stream bed

In this third phase of the project, you can begin to see the stream system coming back to life. The construction crew completed construction on one side of the stream channel and reconstructed flood benches to store more water during heavy storms. We also revegetated the new bank with native plants found on site: willows, alders, Joe-Pye weed, cattails, arrowhead, mint, and other grasses and sedges. These plants will provide a diversity of plant materials that will continue to propagate the bank as existing plants drop their seeds.

Step four: Inviting life back in

Removing small, aging dams from streams improves Vermont’s flood resiliency and our biodiversity. Removing the Simpson’s dam and restoring the riverbed to its natural state protects ring-necked snakes, green frogs, and several kinds of salamanders. Blue spotted salamanders, which can be found in nearby vernal pools, also spend part of their lives in this floodplain.

Dealing with a degraded stream?

Private landowners play a critical role in restoring the health of our watersheds and improving our state’s flood resiliency. Contact us to learn more about how to restore stream health on your property and reduce the impacts of flooding downstream.