WEST PALM BEACH, Fla. - An $880 million plan to improve Everglades water quality was given federal approval Wednesday, setting the clock on a massive 12-year cleanup project.

The Environmental Protection Agency approved permits for the proposal, calling it a “milestone in restoring America’s Everglades.’’

The Everglades are a key water source for South Florida residents, but have been damaged for decades by the intrusion of farms and development. Dikes, dams, and canals have drained much of the swamp and polluted it with fertilizers and urban runoff.

State and federal governments’ efforts to restore the wetlands have been stymied by funding shortfalls, legal challenges, and political bickering.

“It wraps up almost a decade of arguing over what the best thing to do is,’’ said Julie Hill-Gabriel of Audubon Florida. “This . . . is an agreement that these are the right steps to move forward and sets very stringent deadlines.’’

The project will construct and authorize water treatment areas in an effort to filter phosphorous, which promotes unhealthy vegetation that chokes native plants.