The oldest environmental battle in Florida is taking a new turn.

Ever since Richard Nixon occupied the White House, environmental activists have been clamoring to tear down the dam that’s blocking the Ocklawaha River from flowing freely through Central Florida.

Originally known as the Rodman Dam, it was later renamed the Kirkpatrick Dam after former Sen. George Kirkpatrick, who battled for years to keep it intact. In a classic Florida irony, the dam is next to the Marjorie Harris Carr Greenway, which is named after the woman who led the fight to tear it down.

The dam, built as part of the aborted Cross-Florida Barge Canal, created the 9,000-acre Rodman Reservoir. The reservoir is full of bass, which is why anglers have strongly resisted the dam’s removal. The canal was halted by Nixon, largely thanks to the efforts of Carr’s group, the Florida Defenders of the Environment. (What’s left of the canal property became the greenway.)

Carr’s group, formed in 1969 to battle the canal, announced Wednesday that it will now file suit against the U.S. Forest Service, demanding it tear down the dam and let the Ocklawaha flow once more. This is the first time anyone has sued the Forest Service over the dam, according to University of Florida law school professor Joe Little, who is one of the plaintiffs.

When the dam was built, it flooded 600 acres that was part of the Ocala National Forest. Drowned trees turned into stumps that help hide the bass. The state has continued operating the dam with the Forest Service’s permission to occupy that land. But the permit expired years ago and the state Department of Environmental Protection has not tried to renew it, according to FDE attorney Jane West.

Over the decades many people have tried repeatedly to tear down the dam -- both Lawton Chiles and Jeb Bush vowed to do it, and Sen. Jack Latvala backed its removal in 1998 -- but nothing has succeeded. Even the Forest Service was in favor of the destruction in 2002, contending that the dam is ruining water quality in the Ocklawaha, reducing downstream productivity by fish and shellfish in both the Ocklawaha and the adjacent St. Johns River, and spreading exotic and nuisance plants such as hydrilla, not to mention blocking the passage of manatees and other protected species.

But those efforts have been repeatedly thwarted by bass-fishing fans of the reservoir, some of them state legislators such as Kirlpatrick and Sen. Jim King. Supporters of the dam say it has created its own thriving ecosystem which should be preserved.

“It seems like we've been sitting in this limbo for decades,” West said. “The political players who were against removal have all died. I don‘t understand why this is continuing to be an issue, but it is.”

Last year FDE filed a petition asking the Forest Service to take administrative action to kick the state off its land and tear down the dam. The federal agency rejected that petition, saying only that it was working with stakeholders to find a solution. West said that came as a surprise to her clients because they’re stakeholders too, and had not been included in any discussions.

Thus, West said, the lawsuit is the next step. She said it would be filed in federal court next Monday. A request to the Forest Service for comment Wednesday drew no immediate response.