Federal regulators Thursday gave final approval for removing the Saccarappa Dam, a hydroelectric facility on the Presumpscot River in downtown Westbrook, a project expected to expand fish migration.

The Federal Energy Regulatory Commission issued a so-called surrender order, which means FERC has signed off on the dam removal. The order follows a settlement agreement reached by dam owner Sappi North America, Friends of the Presumpscot River, the Conservation Law Foundation and the city of Westbrook.

Removal of the 322-foot-long dam is expected to start next year, with a new fish passage in place by no later than May 1, 2021, when fish runs begin. The dam is bisected by a small island, which creates eastern and western river channels. The settlement agreement has been years in the making.

“We are pleased that the dam removal has been approved by all stakeholders so that we can commence this important project,”  Olga Karagiannis, spokesperson for Sappi North America, said in a statement.

Sappi’s Westbrook mill is located on Cumberland Street. The company, formerly S.D. Warren, was founded in the 1800s.

Once the dam is removed, the river will become home to “an abundance of anadromous fish spawning habitat, habitat that will be capable of supporting hundreds of thousands of alewife and blueback herring, tens of thousands of American shad, and a small population of endangered Atlantic salmon,” Friends of the Presumpscot River and the Conservation Law Foundation said in a joint statement.

Anadromous fish are born in freshwater, migrate to saltwater where they mature, and then migrate back to freshwater to spawn. River herring and alewives are a staple food for bald eagles, osprey and striped bass.

“Based on the experience in other locations in Maine where dams have been removed, the increase in these fish populations will bring eagles, osprey and heron back to the Presumpscot as well as other wildlife,” the statement says. “Opportunities for sport fishing, as well as recreational canoeing, kayaking and boarding will open up as well.”

Sean Mahoney, executive vice president of the Conservation Law Foundation, said Sappi will be responsible for removing the dam and creating the fish passage to help fish negotiate the rapids that will remain. Mahoney estimated the project will cost around $5 million.

Mahoney said Sappi has also agreed to transfer ownership of a strip of land on the northern side of the Presumpscot River to Westbrook for $300,000 paid by the Westbrook Environmental Improvement Corporation and the Cornelia Warren Community Association, according to Westbrook City Administrator Jerre Bryant.

Bryant said the riverfront property will allow the city to extend its 1.2-mile River Walk, which follows the south bank of the Presumpscot River across the Bridge Street footbridge to the northern bank,  creating a loop trail through downtown Westbrook. The extended trail, running parallel to Brown Street, will allow pedestrians to cross the river on the footbridge or the Black Bridge, a former railroad trestle located downriver from Bridge Street.

Sappi no longer needs the land, which contained a utility line that carried hydropower from the dam, Bryant said.

Bryant said the much-publicized rotating ice disk that formed in the river next to the River Walk last winter publicized a section of downtown Westbrook that newcomers did not know existed. Bryant called the ice disk a wonderful marketing tool. Extending the River Walk to the other side of the river will only generate more interest in the downtown, Bryant predicted.

Bryant said the city is pleased with with FERC’s decision to allow removal of the dam.

“It’s a great advancement for Westbrook and the downtown,” Bryant said. “It really enhances the natural features of our downtown.”