DOVER — Two dams located along the Bellamy River near the Sawyer Mill Apartments could be removed in the next two to three years, according to a feasibility study conducted by the owners of the complex.



Speaking in front of the city’s Conservation Commission, consultant Duncan Mellor, of Waterfront Engineers, outlined some of the results of the study into whether the dams should be either lowered or taken out entirely.



The dams, which Mellor said were constructed sometime in the 1870s, have been designated as high hazard dams by the N.H. Department of Environmental Services. This designation is due to the location of the structures, which are in proximity to the populated former mill buildings, and could pose a significant risk should they fail.



Over the course of the hourlong meeting, Mellor and other consultants outlined some of the potential impacts of removing the dams, including how this would affect aquatic life, sediment buildup and surrounding wetlands.



In 2009, both the upper and lower Sawyer Mill dams, which are privately owned by the Sawyer Mill complex owners, were issued letters of deficiency by the DES.

According to Mellor, the goal of the study was to either settle on modifying the dams to reduce flooding or removing them, which would eliminate barriers to fish passage on the river and restore normal river function, including sediment and nutrient transport. Removing the dams would also eliminate impoundments, areas of still or slow moving water behind the dams.



Danna Truslow, of Truslow Resource Consulting, said one of the most important impacts of removal would be to renew the passage of aquatic species, such as alewife, blueback herring and the American eel, back up the river. Also, removal would create a more natural water flow and transform the open water habitats of impoundments into a narrower river channel.



Mellor said the study, which is almost completed, indicates the most beneficial solution would be taking out the dams, but the process still has some way to go before reaching that point. Consultants will now have to go through permitting processes, apply for further grant funds and eventually engineer the removal of the structures.

That could be at least two to three years away, Mellor said.