It marks the first time in US history that federal authorities have opted to dismantle a functioning hydro-electric dam in favour of returning rivers to species of fish.
The implications for the hydro-electric industry nation-wide could be considerable. There are more than 500 other dams up for relicensing in the US; many are in the Pacific North-west and have been objects of campaigns by environmentalists.
The 900-foot-long Edwards Dam, outside the city of Augusta, in southern Maine, is 160 years old. The Federal Energy Regulatory Commission ruled that it should be removed to open a 19-mile stretch of the Kennebec River for salmon, bass and sturgeon entering from the ocean in search of spawning grounds.
"I think people are beginning to realise that a dam is not necessarily a permanent feature of the landscape," commented Alexander Hoar, a director at the US Fish and Wildlife Service.
The owners of the dam, which provides only 1 percent of Maine's electricity supply, have one year to come forward with a plan for the structure's demolition. However, they are almost certain to appeal against the order.