A recent agreement to remove dams in the Presumpscot River has created a divide between two conservation groups that have been working for decades to restore upstream fish passage in a major Casco Bay watershed.

As part of a negotiated settlement announced last week, Sappi North America has agreed to remove two spillways – or dam headwalls – at Upper Saccarappa Falls in Westbrook and to install a fish passage system around Lower Saccarappa Falls. The company also agreed to either remove or provide fish passage around dams at Little Falls and Mallison Falls once a pre-determined number of American shad and river herring are counted passing Saccarappa Falls.

The agreement was negotiated with representatives of Friends of the Presumpscot River along with other groups. But members of another organization that has worked alongside the Presumpscot River group for years, Friends of Sebago Lake, contend that the pact doesn’t go far enough. And leadership of the group are pledging to fight the agreement.

Roger Wheeler with Friends of Sebago Lake is upset because Sappi would not be obligated to improve fish passage around the Dundee and Gambo dams – both located in the upper half of the 25-mile-long river – until at least the year 2053. Wheeler argued that means the agreement will not restore access to the Presumpscot’s upper watershed to alewives, Atlantic salmon and other sea-run or “anadromous” fish once plentiful prior to industrialization.

“One of the major goals is we want anadromous fish to be able to access the entire Presumpscot River watershed, and that includes Sebago Lake,” Wheeler said. “This agreement ends that.”

Wheeler said members of the organization are discussing their options for challenging the agreement and talking with other organizations. The proposal requires final approval from both the Federal Energy Regulatory Commission, which licenses dam operators, and the Maine Department of Environmental Protection.

Parties to the settlement include: Sappi, Friends of the Presumpscot River, the Conservation Law Foundation, the U.S. Fish and Wildlife Service, the Maine Department of Marine Resources and the city of Westbrook.

The Presumpscot is one of Maine’s oldest industrial rivers – with the first dams erected in mid-1700s – and has been the subject of decades of regulatory and legal machinations over fish passage.

Michael Shaughnessy, president of Friends of the Presumpscot River, said all parties made concessions during the three years of discussions the led to the agreement. Shaughnessy and other supporters argue that the final product, while not perfect, will reopen access to a stretch of river that has been closed to migratory fish for centuries while providing economic and recreational opportunities in Westbrook.

“This was a negotiation and it was a matter of getting it right at Saccarappa (Falls) to allow fish to pass,” Shaughnessy said on Wednesday. “There had to be some trade-offs and the timing (of fish passage at Dundee and Gambo) was one of those. We felt there is a lot of habitat before you get up there.”

The Presumpscot River deal is only the latest dam removal and river restoration project in Maine.

Under the agreement, fish passage around the Lower Saccarappa Falls would be provided by a “double Denil” fish ladder, and by 2024 Sappi would begin operating a fish-counting facility at the exit of the system. The two spillways at the upper falls, which are separated by an island, could come out as early as 2020. The company has also committed to building two fish “channels” at the upper falls that mimic the natural topography of the river bottom.

The number of sea-run fish passing Lower Saccarappa Falls will determine when additional steps are needed to improve passage at the next two dams on the Presumpscot: Mallison and Little Falls.

Sappi or any future dam owner would have two years to construct fish passage around Mallison Dam – or three years to surrender its FERC license and remove the dam – once 2,960 American shad or 18,020 blueback herring are counted passing through the Saccarappa counting facility in one year. Fish passage or dam removal would then follow at Little Falls.

But improvements to fish passage at the Dundee or Gambo dams would not be required for the duration of the FERC licenses, which would be extended to 2053 under the agreement. The agreement states that, “under present circumstances, fish passage at Gambo and Dundee is not required or appropriate, and that the removal of the Mallison Falls and Little Falls dams would not change that finding.”

Friends of Sebago finds that clause unacceptable. Wheeler said he and other members also disagree with another part of the agreement that suspends almost all fish stocking in the Presumpscot until 2025.

“This is one big fight here, and we are going to have to get into it,” Wheeler said.

Although Wheeler said members are still exploring options, it appears the group could contest the issuance of a water quality certification from the Maine Department of Environmental Protection, which is required for the agreement to take effect. Opponents could also challenge the process in court.

“If you put passage in at Dundee and Gambo, you have a lot of river habitat that’s been opened up,” Wheeler said.

Shaughnessy was aware of the criticism but defended an agreement that resulted from years of discussion.

“It wasn’t necessarily that anyone saw it as a perfect solution … but it was what we came to over three years” of negotiations, Shaughnessy said. “And over the long run for the river, it is a good deal.”