A facility to trap fish and carry them upriver will be installed next to an existing fish ladder off Liberty Street as a temporary solution to fish passage over the Rollinsford Dam.
The “trap and transport”operation, which would primarily move herring, would carry truckloads of fish up the Salmon Falls River for several weeks each spring to support natural migration around the Rollinsford Hydroelectric Project.
The South Berwick Planning Board voted unanimously last week to approve the plan and move it to the last stage, which requires only signing the agreement.
The new fish feature proposed at the site of the South Berwick Hydroelectric Project near Counting House Park is the first such facility Green Mountain Power, which owns the project, has overseen at any of its hydroelectric facilities.
The South Berwick location was proposed as a temporary solution because more study is needed before a multi-million dollar fish passageway can be designed at the Rollinsford Dam, where space is limited and more studies on fish movement are required.
Fish will swim into a hopper near the fish ladder and be hauled out, transferred to a holding tank, and driven upriver to be released somewhere beyond the Rollinsford and Somersworth dams, explained engineer Kevin Cassidy of Gomez and Sullivan, an environmental consulting firm with offices in Henniker, N.H., who presented the information to the Planning Board at its Feb. 13 meeting.
The Rollinsford Hydroelectric Project at Lower Great Falls near the railroad trestle received a license renewal in 2022 from the Federal Energy Regulatory Commission, which regulates most hydropower dams nationally.
The renewal came with the condition that Green Mountain Power install upstream fish passage at the Rollinsford dam, which now has no passage. The Rollinsford hydro project is leased by Green Mountain Power from the town of Rollinsford, which owns the dam.
American shad, American eel, and river herring still live in the river, but herring are expected to make up the bulk of the fish being moved, Cassidy said.
The transfer will be done either by a state agency, such as New Hampshire Fish and Game or Maine Inland Fish and Wildlife, or a private company engaged in fisheries work, according to John Tedesco, project coordinator from Green Mountain Power.
Trucks would enter through a deeded right of way through the Counting House Park parking lot to the hydroelectric plant, according to the plans presented to the Planning Board.
During the migratory season – typically April 15 to June 30 – fish run in large numbers for a short time, so active transporting would be concentrated to a couple of weeks, Tedesco said. Fish would be moved by pickup truck and trailers to release sites determined by federal and state fish and wildlife agencies, he said.
During peak migratory season, transporting crews may be operating during all daylight hours, making as many as eight trips at day, he said.
The exact timing is hard to predict because fish runs happen at certain temperatures. As the season progresses and waters warm, the fish move farther north and the runs in southern Maine dwindle, Tedesco said.
“Fish behave the way fish do,” Cassidy added..
The existing fish ladder at the South Berwick dam handles both fish that need to move upstream to spawn and fish like the American eel that need to move downstream to spawn. A fish counter at the dam recorded 177,374 river herring passing through the ladder in 2024, according to the Low Impact Hydropower Institute website.
Planning Board members, considering the impact that trucks moving fish could have on public use of Counting House Park and on the neighborhood, agreed the transport must obey the local noise ordinance and that a grass grid that strengthens the access road must be 12 inches deep, not six inches as first proposed.
