FARMINGTON — Town officials have negotiated the estimated cost of stabilizing the eroding bank along the Sandy River at Whittier Road to $238,000, Town Manager Richard Davis said at an update on the project Tuesday evening.

Davis told the Board of Selectmen that the town will not know the final cost for at least three weeks, until after a bid is accepted on the project. Initial estimates from the U.S. Forest Service, which is overseeing the project, had the project costing $363,000, while Davis said the town was looking to spend around $300,000.

Davis said the forest service originally estimated the project to span 400 feet, but it will needed to span only 300 feet of the bank. They also have found a cheaper and more local option to buy the rocks needed for the structure.

Public Works Director Denis Castonguay said previously that he has been checking the bank daily to watch for further erosion. Davis said the bank had eroded to 30 feet from the road. He said every time the river rises and then recedes, it pulls more material from the bank and continues to destabilize it.

Officials estimated earlier in the year that the stabilization project will cost between $280,000 and $320,000, though the town pays just 25 percent of the total cost because of a grant through FEMA.

Town officials have been eager to make progress on the project because there is an increased likelihood the river will swell and collapse the road or at least damage it enough for the town to close the section as a precautionary measure. The town can also build along the riverbank only between July 15 and Sept. 15, so as not to disrupt the endangered Atlantic salmon, which use the river as spawning ground.

The town has been trying to stabilize the bank, which has eroded to 30 feet from the road, since August 2011 when a storm caused a 50-foot-wide, 300-foot-long chunk of earth to fall into the river.

The town adopted a project that uses interwoven logs with the root base attached and boulders to create a strong base that would effectively remove the risk of the road collapsing from erosion. The project eventually will amass debris floating downstream and naturally add more material to the stabilized embankment.

Davis said a local contractor should be able to build the structure and the forest service would oversee the project.

According to the project timeline from U.S. Forest Service, construction tentatively will get under way July 29 and last to Aug. 9.

Kaitlin Schroeder — 861-9252
[email protected]