WALPOLE, N.H. – As part of a multiyear biostabilization conservation project to help repair eroding riverbanks along the Cold River in Walpole, the Connecticut River Conservancy (CRC), with the help of Canonica Landworks, recently utilized nature-based engineering and materials to address the unstable banks.
Because of the flash-flood nature of the Cold River, the banks have gradually degraded over the decades. This biostability project is supported through funding from Natural Resources Conservation Services (NRCS) to help landowners, farmers, and rural communities conserve natural resources.
CRC crews installed large amounts of wood materials, including logs and root wads, to create a stabilizing “floodplain bench” designed to absorb the force caused by high river flows along the flash-flood-prone Cold River banks.
Caitlin Maguire is the New Hampshire restoration project manager for the CRC at the Cold River site, where the crew recently completed a biostabilization bank restoration project for a landowner who had lost approximately 30-40 feet of land in just the last five years.
“We are here to do a root-wad installation with a bench and soil lifts to try and rebuild shoreline along the river,” Maguire stated in a video presentation produced by the CRC.
Canonica Landworks is a restoration contractor based in Chelsea, Vt., that assisted the CRC in the step-by-step restoration procedure. “We did some initial layout with the engineer, basically, determining where we were going to put the (tube-styled) cofferdam, because, working in New Hampshire, we are required to isolate our working area from the moving water,” owner Ben Canonica also stated in the video presentation.
“Once the cofferdam was in place, we installed 22 root wads along the bank. Once they were in place, we anchored all the root wads with large boulders and then a footer log went underneath them.
“This is protecting the toe of the bank and then, over time, they will slowly degrade, and then the bench step areas above it will be planted with shrubs and trees. Over more time, the roots from those shrubs and trees will take hold and help to hold the bank in the longer term.”
Essentially, this biostabilization project created a flood bench behind the root wad so that when the high water does get above the bank-full elevation, it will be able to get up on the bench.
“Then, on the back of the bench, in order to hold than bank,” Canonica concluded, “we’ve installed some fabric-encapsulated saw logs and worked our way towards the corner [of the owner’s property], then this will all get seeded and planted this coming spring.”
The funding for this project comes from the Regional Conservation Partnership program, which is grant funding provided by the NRCS department of the USDA and used for agricultural producers, or anyone who has farmland, timberland harvest, or livestock on their land.
Farmers and landowners can apply to have work done on their properties that would also benefit the environment around them.