The decade-long effort to reopen nearly 1,000 miles of fish habitat in central and northern Maine surpassed a milestone last week when a coalition purchased three major dams on the Penobscot River north of Bangor.

The coalition of organizations working together as the Penobscot River Restoration Trust officially took possession of the Veazie, Great Works and Howland dams from PPL Corp. on Friday in a historic deal worth $24 million.

Next up for the coalition: complete plans to start dismantling or bypassing the dams over the next several years.

“We will begin work on Great Works this summer and work will begin on Veazie the following summer [in 2012],” Laura Rose Day, executive director of the Penobscot River Restoration Trust, said Monday. “These are essentially large deconstruction projects.”

The Penobscot endeavor has been hailed internationally as a model river restoration project.

Under an agreement brokered in 2004, PPL agreed to sell the three dams to the trust for roughly $25 million. PPL, in return, gained authorization to increase power generation at six other dams along the river, entirely offsetting the generation losses incurred when the Veazie, Howland and Great Works dams are decommissioned.

Click here to see a sketch of the restoration plan.

“This landmark partnership has proven that business, government and interested citizens can reach mutually agreeable solutions that benefit the community, the economy and the environment,” Dennis Murphy, a vice president and chief operating officer at PPL, said in a statement Monday.

The trust estimates it will take another $25 million to remove the Veazie and Great Works structures — the first two dams fish encounter on the Penobscot — and to decommission and build a state-of-the-art fish bypass at Howland.

Once complete, the project will have reopened nearly 1,000 miles of river and streams within the Penobscot watershed to endangered Atlantic salmon, sturgeon, American shad, alewives and seven other species of migratory, sea-run fish. In turn, those species help support other commercially important species, such as cod and lobster.

“This may well turn out to be the most important day for Atlantic salmon in the past 200 years,” Bill Taylor, president of the Atlantic Salmon Federation, said in a statement Monday. “The Penobscot project is our best — and perhaps last — chance of restoring a major run of wild Atlantic salmon in the United States.”

But supporters insist fish and other wildlife won’t be the only beneficiaries. They also predict that fishermen and tourists will be drawn to the freer-flowing river.

Chief Kirk Francis of the Penobscot Indian Nation said tribal members see considerable opportunities in ecotourism. But the project is also important culturally and philosophically for the tribe, which is part of the Penobscot River Restoration Trust coalition.

“We view the river as a very sacred entity. It’s been our life-source for thousands of years,” Francis said. By participating in the project, Francis added, the tribe is helping to “bring some health back to the river.”

Of course, a project of such magnitude is bound to generate some controversy. A small but vocal group of fishermen have expressed concerns that the changes will allow invasive northern pike to infiltrate upper tributaries, threatening prized brook trout and landlocked salmon fisheries.

But federal regulators ruled that the benefits of unrestricted fish passage outweighed any risk from northern pike.

Both the Great Works and the Veazie projects are expected to take roughly one year to complete. At Veazie, crews will have to remove not only the main dam, which measures 900 feet long and 25 feet high, but also an earlier, now-submerged dam just upstream.

Once those dams are removed, the Milford dam visible from downtown Old Town will be the first impediment to upstream passage for fish.

Black Bear Hydro Partners LLC, the company that bought the Milford dam and five other dams from PPL in 2009, will build a new fish lift and trap at Milford before the Veazie dam’s removal. That trap will allow biologists to collect brood fish for the Atlantic salmon hatchery run by the U.S. Fish and Wildlife Service.

The coalition is roughly one-third of the way toward its next goal of raising $25 million to pay for the remainder of the project.

Mike Tetreault, executive director of The Nature Conservancy in Maine, said his organization was heavily involved in fundraising during the first stage and will continue to solicit both private money and federal support for the project.

“We are working with our partners to help close out the last $16-17 million,” Tetreault said.