A 162-year-old dam spanning Maine's Kennebec River gave way to pressure from Congress and environmentalists yesterday as bulldozers began demolishing the structure. Removing the Edwards Dam opens up an additional 17 miles (27 km) of spawning grounds to several fish species, including Atlantic salmon, shad and the endangered short-nose sturgeon. The dam's license with the Federal Energy Regulatory Commission expired in 1993. Congress, under pressure from environmental groups four years later, forced FERC to consider the environmental impacts of dams.