Reconstruction of Lock Dam, Allagash Wilderness Waterway

By Regional Fisheries Biologist Frank Frost

Lock Dam was rebuilt in 2018 by the State of Maine in a project that State and Federal agencies hope will be a huge benefit to canoeists and anglers.  A huge effort by Allagash Waterway staff, led by Superintendent Matt LaRoche, over a couple of years resulted in a completed project in October last year; MDIFW consulted with technical input related to fisheries and fish habitat.  2019 marks the first year since the early 1960s that flow in Martin Stream, the connection between Chamberlain and Big Eagle Lakes will be much closer to a normal stream, providing ideal water flows for canoeists and much improved habitat for native fishes.  In the future, agencies will work together to monitor the success of the project including spawning by lake whitefish and brook trout. 

Lock Dam sits at the natural outlet of Chamberlain Lake where all water from the Chamberlain/Telos Lake watershed at one time flowed north into Big Eagle Lake.  In the 1840s the watercourse was changed drastically to accommodate movement of wood south to markets in Bangor.  Lock Dam was built in 1841 which diverted water normally flowing north, through the Telos Cut, a dug channel connecting Telos Lake with Webster Lake – now wood could easily be moved from the Allagash to the Penobscot River.  Over the years, Lock Dam was modified several times, but in 1961 a 36-inch culvert was installed in the earthen berm.  The culvert was a bad fix for fish and fish habitat.  Not only was it undersized allowing only a small percentage of the historic water flows to go north, it blocked fish passage including lake whitefish, a species that has declined significantly in northern Maine. 

Through consultation with MDIFW, the new Lock Dam will provide much better habitat for fish.  While it still blocks upstream fish passage, due to invasive fish present in Big Eagle Lake, the new structure will allow higher flows in the stream creating a more natural stream system.  Winter water flows will also be enhanced so that brook trout spawning areas will not be dewatered as was common in the recent past.  We will also be monitoring the stream closely to determine whether a lake whitefish spawning run can be reestablished.  Initial inspection of the habitat in May 2019, after only one spring of higher flows, shows that the habitat is greatly enhance already, a sure sign this project will be a win-win for all stakeholders.