BRADLEY, Maine — Workers began removing the Great Works dam late Monday morning, part of a historic effort to open nearly 1,000 miles of habitat to 11 species of fish that haven’t had open access to the Penobscot River for two centuries.

U.S. Interior Secretary Kenneth Salazar joined about 300 conservationists, government officials, tribal leaders and residents to witness the first tangible step in what has been a 13-year push to revive the river.

“Today marks an important milestone for river conservation in America,” Salazar said moments before heavy equipment operators fired up their engines. “Through a historic partnership that exemplifies President Obama’s America’s Great Outdoors Initiative, we are reconnecting 1,000 miles of river, restoring vital habitat for fish and wildlife, expanding opportunities for outdoor recreation, and supporting energy production, jobs and economic growth in communities throughout Maine.”

The Great Works dam stretches across the Penobscot River from Bradley to Old Town. The Veazie dam also is slated for removal beginning in 2013, the Milford dam will get a new fish lift, and a fish bypass will be built at the Howland dam. The project, led by the Penobscot River Restoration Trust, has been called the biggest river restoration project in the eastern U.S. and is expected to cost about $62 million.

Crews from Ellsworth-based R.F. Jordan & Sons Construction Inc. used two excavators with hoe ram attachments — essentially large jackhammers — to break apart the fishway portion of the 1,000-foot-long dam piece by piece. A third excavator scooped up debris and loaded it into a dump truck that hauled the rubble off site.

Demolition is scheduled to be completed in November.

Dams, overfishing and pollution have drastically cut the number of sea-run fish that make it north of Bangor in the Penobscot. Before humans began altering the river, between 75,000 and 100,000 Atlantic salmon traveled through Bangor on their annual runs, according to the restoration trust’s deputy director, George Aponte Clarke. Today, only about 1,300 make it that far. Between 14 million and 20 million river herring made it upriver in the past, while fewer than 1,000 make it today.

Those fish populations will begin to bounce back in the years after the removal of the dams, fishery experts and trust officials have said.

The recovering fish population will boost economic growth and ecotourism opportunities in the Penobscot watershed, according to trust director Laura Rose Day.

U.S. Reps. Mike Michaud and Chellie Pingree spoke at Monday’s event and U.S. Sens. Olympia Snowe and Susan Collins sent staff members to read written statements. The politicians lauded the restoration project as an example of collaboration among utilities, conservationists and fisheries groups that at one time clashed over the future of the river.

The restoration trust is made up of 17 conservation groups, the Penobscot Indian Nation, government entities and corporations.

“The restoration of this river would not have been achievable without a commitment to common sense and consensus building,” Snowe said in a statement read at the event. “Together, you have forged a new-century solution to an old-century problem, which will maximize the public benefits of this tremendous river in terms of ecology and energy.”

Salazar announced during the dam removal event that $2.5 million in federal funds will go toward Penobscot River restoration efforts, and Eric Schwaab from the the National Oceanic and Atmospheric Administration said that agency will kick in another $1 million.

“It’s truly inspiring to see the Penobscot coming back to life, and not just because of what it means for wildlife and people,” said Dan Ashe, director of the U.S. Fish and Wildlife Service. “This internationally recognized project represents the future of business and government at all levels.”

The Penobscot Indian Nation has been a longtime advocate of the river restoration project and was one of the early members of the trust. During the ceremony, before workers began chipping away at the dam, tribal elder Butch Phillips said the river is an integral part of the tribe’s culture.

“The ancestors are smiling today,” he said.

Penobscot Chief Kirk Francis said the removal of the dams will reunite the tribe with its historic homeland and the customs and traditions that come along with a thriving river, which he described as the lifeblood of the tribe for thousands of years.

“To the Penobscot people, today is about much more than simply removing a dam,” Francis said during the ceremony. “Today signifies the most important conservation project in our 10,000-year history on this great river that we share a name with and that has provided our very existence.”

The dam removals will not reduce energy production on the Penobscot, according to the trust. Black Bear Hydro Partners LLC, owner of the dams, received approval in September 2011 to upgrade the Stillwater and Orono dams to eliminate the energy production gap left by the demolition of the Great Works and Veazie dams.

Gov. Paul LePage criticized the dam removal plans during a press event last Wednesday at which he announced the first listing of Maine’s “business-friendly” communities.

“I think it’s irresponsible for our country to be taking out hydro dams,” LePage said. “I think we need to put more in.”

Maine Department of Marine Resources Commissioner Patrick Keliher, who spoke at Monday’s event on behalf of the governor, said LePage’s comments stemmed from his support of hydroelectric power as an important asset in Maine’s broader energy policy.

Keliher said the aims of the restoration project are “the embodiment of many of the goals of the LePage administration.”

Those goals include increasing economic and business prospects as well as rebuilding fisheries and reviving the river, he said.

“[LePage] does very much appreciate the long history that has brought the Penobscot project to this stage,” Keliher said. “The positive outcomes for both energy and environment that have resulted are key.”

Keliher said he expected runs of salmon, shad and striped bass to rebound dramatically in the years after the dam removals.

“Though there is no salmon fishing here today, the best chance we have in Maine to once again have a fishery is to fully implement this project,” the commissioner said.

The complex river restoration deal got its start in 1999, after Pennsylvania-based PPL Corp. purchased dams along the Penobscot River. The company soon started having discussions with the state, Penobscot Indian Nation, U.S. Department of the Interior and several Maine conservation groups to hash out solutions to issues involving hydropower relicensing, migratory fish passage and restoration of the river.

Under the 2004 agreement, PPL would sell six dams in Milford, Orono, Stillwater, Ellsworth, Medway and West Enfield to Black Bear Hydro, and the restoration trust later would purchase the Veazie, Great Works and Howland dams.

Those deals came to fruition. In 2009, PPL sold the six dams and their associated hydropower assets to Black Bear Hydro for $81 million. The next year, the trust bought the dams in Veazie, Old Town and Howland for $24 million with plans to demolish the Veazie and Old Town dams and build the fish bypass in Howland.

“Today is a great day for the people, fish, wildlife and communities of the Penobscot River,” said Lisa Pohlmann, executive director of the Natural Resources Council of Maine. “The removal of the Great Works dam, combined with other aspects of the Penobscot River Restoration Project, mean that the largest river in Maine will get a new lease on life.”

Editor’s note: Bangor Daily News Publisher Richard J. Warren is co-chairman of the Penobscot River Restoration Trust’s capital campaign and U.S. chairman of the Atlantic Salmon Federation, one of the partner organizations of the trust.

The Associated Press contributed to this report.