Papermill Pond Dam Removal and River Restoration Project

The Ousatonic Fish and Game Protective Association, Inc., in partnership with the Connecticut Department of Energy and Environmental Protection’s Inland Fisheries Division, sought to remove the Papermill Pond Dam on the East Aspetuck River to restore fish habitat formerly exceptional in quality for trout, facilitate fish passage through the site, and improve accessibility and functionality for people to engage in outdoor activities at the site in order to foster deeper stewardship ethic for the watershed.

The Papermill Pond Dam, located in New Milford, is an embankment dam situated on the East Aspetuck River. It is located 2.9 miles upstream of the confluence with the Housatonic River and is the first barrier on the East Aspetuck River. The spillway is concrete capped with masonry core. It has an approximate structural height of 11 feet and length of 75 feet.

The following alternatives were analyzed: 1) no action; 2) fishway bypass channel around dam; 3) technical fishway at dam; 4) dam lowering with fishway at dam; 5) river bypass and off-line pond; and, 6) full removal. Conceptual designs were developed for each alternative. Each alternative was analyzed and rated numerically relative to twelve categories: river morphology, aquatic resources (fisheries, macroinvertebrates, water quality), recreation, historic resources, flooding, relative liability, relative short-term costs, relative long-term costs, availability of funds, and anticipated permitability. Dam removal ranked as the most feasible alternative, but dam repair stood out as the best option for maintaining the existing ease of recreational access. That alternative necessitated dam repair, ongoing maintenance and inspection, both short-term and long-term sediment dredging, and construction of a fish bypass channel. The Association considered the alternatives and decided to pursue full dam removal.

Based on negotiations with CTDEEP that considered impacts to downstream habitats and other applicable regulations, the resulting recommendation was to remove a portion of the impounded sediment prior to passive release of the remaining impounded sediment, regardless of potential contamination. This minimized transitory sediment deposition in downstream habitats, thereby reducing the short-term impacts of the project. Thus, sediment proximal to the dam is proposed to be excavated and permanently deposited in upland areas onsite.

The dam was successfully removed in 2019 under supervision of CTDEEP Fisheries Division and Princeton Hydro.