New York State Department of Environmental Conservation (DEC) Acting Regional Director Joe Zalewski today announced the release of final plans to improve the Imperial Mills Dam, including installing a fish ladder to provide for passage of landlocked Atlantic salmon and modifying the dam to bring it into compliance with dam safety regulations. The Imperial Mills Dam, also known as the Main Mill Dam, is located on the Saranac River approximately 3.2 miles upstream from Lake Champlain, in the city of Plattsburgh, Clinton County.
“DEC is moving forward with plans to improve the Imperial Mills Dam to reconnect landlocked Atlantic Salmon to their spawning habitat and to ensure public safety. DEC’s engineering and fisheries experts have carefully crafted this important plan and we look forward to advancing this project and improving the dam to benefit the surrounding community and local ecosystem,” said Acting Regional Director Zalewski.
Before finalizing the plan for the dam, DEC conducted stakeholder outreach including a meeting with Clinton County officials. The new fish ladder will provide landlocked Atlantic salmon in Lake Champlain access to potentially up to 10 miles of historic spawning habitat-more than any other river on the New York side of the lake. Fishery survey data of the Ausable, Boquet, and Saranac rivers indicate that the Saranac River has a greater amount of quality spawning habitat and more juvenile salmon habitat than the other rivers. Public access along the Saranac River also provides fishing opportunities. Restoring landlocked Atlantic salmon access the spawning habitat in this section of river will benefit the State’s ongoing restoration efforts for this species in Lake Champlain.
Other improvements to the dam include repairing the outlet gate, reconfiguring the crest of the spillway, adding rock anchors to improve spillway stability, and lowering the embankment. DEC is the partial owner of the dam structure. The dam is currently considered a ‘Class C high hazard dam,’ because if it were breached during a severe storm event, a nearby residential area and a building on Pond Street would likely experience flooding. These locations would be expected to experience little or no flooding if the dam were breached during typical storm events. The dam embankment is stable and the work will bring the dam into compliance with dam safety regulations.
“As an adjacent property owner to the Imperial Mills Dam, Imperial Industrial Park supports DEC’s plans for the dam and appreciates their efforts to research and understand the impact of changes to the dam,” said Doug Butdorf, Property Manager, Main Mill Street Investments, LLC, Imperial Industrial Park. “DEC’s plan to maintain the current crest elevation, will allow our tenant, an experienced New York State hydropower development company, to quickly re-energize and improve the existing hydropower capacity of the facility, helping to meet the state’s mandated increase in renewable energy capacity and possibly supply a robust power source for the nearby Plattsburgh International Airport.”
In addition, in consultation with the Northern Forest Canoe Trail (NFCT), DEC will build a new carry trail to allow safe passage around the dam for paddlers. Upon completion of work on the dam, NFCT plans to construct and maintain the path, which will include a landing, stone steps, and signage directing paddlers around the dam.
“Currently, paddlers portaging the dam drag boats up a steep bank and through a hole in a fence,” said Noah Pollock, Stewardship Director, Northern Forest Canoe Trail. “We are excited to work with DEC to construct a safer, more appropriate carry trail.”
Previous designs to improve the dam included lowering the level of dam, requiring the removal, management, and disposal of 90,000 cubic yards of sediment from behind the dam. The proposed disposal of this sediment would have resulted in filling of a wetland, which the U.S. Army Corps of Engineers (USACE) would not permit under a Nationwide Permit. The current plan does not require extensive removal of river sediments, filling or loss of wetlands, and – based on a pre-application meeting with USACE – the proposed fish ladder and dam modifications can be conducted under the existing authority of a Nationwide Permit.
DEC is currently completing designs for the project and expects to begin construction in 2022, and complete the project in 2023.
Adirondack Almanack file photo