The long-delayed start of the dam-removal project is expected to end years of rancor and uncertainty. Plans to dismantle the dams began in 1999, when PPL Corporation, a power company, bought a series of Penobscot River dams from Bangor Hydro Electric Company. Wanting to avoid the conflicts that had accompanied dam-licensing efforts on the river, PPL began negotiating with the Penobscot Indian Nation and several conservation groups. They agreed on a deal that allowed PPL to sell several dams for removal or decommissioning, while increasing power generation at six other dams to offset the power losses.

The Federal Energy Regulatory Commission signed off on the agreement in 2004.

“The backdrop for the negotiations was total rancor on the river, over every individual dam relicensing,” said Laura Rose Day, executive director of the Penobscot River Restoration Trust, a coalition formed by the tribe and conservation groups to buy and remove the dams.

Image The Penobscot River still has a large run of Atlantic salmon. Credit... The New York Times

Still, not an ounce of concrete had been touched until Monday. First, the trust had to raise $25 million to buy the dams from PPL, which it accomplished in 2010. Then it had to raise more money to take them down.

The Penobscot still has the nation’s largest run of Atlantic salmon, which are listed as endangered under the Endangered Species Act. The fish are trapped at a fish ladder on the Veazie Dam, between the Great Works Dam and the ocean, and trucked upriver or to hatcheries. More than 3,000 salmon returned to the river in 2011, the largest run in 25 years, but historic runs were most likely 20 times that size.