The plan shores-up the dam to bring it into compliance with dam safety regulations and adds a carry for paddlers and a fish ladder to provide for passage of landlocked Atlantic salmon. There have been calls to remove the dam entirely, including by Lake Champlain Chapter of Trout Unlimited and the City of Plattsburgh and return the river to a more natural state and reduce the threat of flooding in the city. DEC’s announcement said they met with Clinton County officials before finalizing the plan.
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.
Other planned work at the dam includes 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.
In an announcement about the dam plans, DEC said “the dam embankment is stable and the work will bring the dam into compliance with dam safety regulations.”
DEC decided that lowering or removing the dam would require removing, managing, and disposing of 90,000 cubic yards of sediment from behind the dam. The proposed disposal of this sediment would have resulted in filling a wetland, which the U.S. Army Corps of Engineers (USACE) would not permit under a Nationwide Permit.
“The current plan,” DEC’s announcement says “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.”
The fish ladder would provide landlocked Atlantic salmon in Lake Champlain access to 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. Restoring landlocked Atlantic salmon access the spawning habitat in this section of river is expected to benefit ongoing restoration efforts for this species in Lake Champlain.
In addition, in consultation with the Northern Forest Canoe Trail (NFCT), DEC has agreed to build a new carry trail 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.
DEC is currently completing designs for the project and expects to begin construction in 2022, and complete the project in 2023.