Largest river restoration project reaches completion
October 29, 2009
WOODSTOCK—The largest river restoration of its kind in New Hampshire is just being completed, with 2,900 feet of the Pemigewasset River restored to its original course and banks restored to their previous condition.
Most of the project was on an 80-acre lot belonging to Errol and Kelly Chase, both of whom were thrilled to support the project, according to Kelly.
Todd Baldwin, of the Pemigewasset Chapter of Trout Unlimited, took the lead on this project six years ago and was thrilled to see it come to fruition.
"This is exciting for me, I could watch them move every spoonful of earth," Baldwin said recently, while watching equipment belonging to Coleman Construction, of Conway, move huge rocks in the river to channel the water.
Tyler Philips, of Horizons Engineering, who oversaw the work on the site, said the purpose of the huge rocks and the walls they were building along the banks was to "train the water" so that it would naturally flow along a certain route.
"It took many years for this problem to develop and it's going to need some help for it to follow the new channel," Philips said.
The 2,900 foot stretch of river had to be restored because in the mid-1990s the river breached its bank and created a new river bed through what had been a 30-acre pond on the Chases' property, Baldwin said. Much wildlife habitat was lost, including prime fishing ground, he said. Just in the past year over three acres of land had been lost to the new path of the river.
The pond had been created when Interstate 93 was built and gravel was taken out to build the interstate. Water filled in the gravel pit, creating a large pond, Baldwin said.
After Trout Unlimited became involved, Baldwin said Horizons Engineering was contracted to do a feasibility study on the proposed project to redesign the river channel and then contacted the New Hampshire Department of Environmental Services, which was quite enthusiastic about the proposal.
The cost of the project is over $600,000, Baldwin said. About $200,000 of that is the value of the material being taken right from the property, including stone, gravel, plants and trees, which are being transplanted from elsewhere on the property.
The Chases are donating all the material, which is helping considerably with the cost, Baldwin said. The remaining $400,000 came from grants. The largest grant came from the state to the tune of $317,000, which was the largest grant to a non-profit in the state, Baldwin said.
Philips said the project was also the largest river restoration of its kind in the state. Usually river restorations involve temporary fixes such as installing plastic mesh called riprap to hold up banks, or just fixing small sections of bank. Nothing of this size had been tried in New Hampshire before, he said.
The key to this project was figuring out what the problem was to begin with that caused the river to breach its bank, Philips said. The problem was the river was too broad in the area where it breached and sediment built up raising the bed, so that in large floods it easily broke its bank, which it did one too many times, he said. By making the river narrower and deeper in that area sediment does not have a chance to build up and is carried downstream, he said.
Over 90,000 cubic yards of material were moved for this project, Baldwin said.