AUGUSTA – Alewives, shad, blueback herring and Atlantic salmon are expected to benefit when new fish passages on three dams open this spring as part of an agreement signed in 1998.

The agreement among the state of Maine, federal energy regulators, hydroelectric dam operators and a coalition of conservation groups resulted in the removal of Edwards Dam from the Kennebec River in Augusta in 1999.

When the 162-year-old dam was breached, it allowed migratory sea-run fish to swim an additional 17 miles upriver to Waterville.

As part of that same agreement, fish lifts are expected to open on three more dams this spring, allowing the fish to swim even farther upriver to spawn.

The lifts are being built by the Pittsfield-based Cianbro Corp. at the Lockwood Dam on the Kennebec River in Waterville and at the Benton Falls and Burnham dams on the Sebasticook River, which flows into the Kennebec at Winslow.

All three lifts are scheduled to be operational by May 1. There are several more dams upriver on both rivers.

Gail Wippelhauser, a researcher with the Department of Marine Resources, said the fish passages should help the fish populations in the rivers.

“We’re trying to have these dams have passage so that the shad, alewives, blueback herring and salmon get back to their historic habitat,” she said.

In Waterville, a $2.4-million fish lift is being built and paid for at the Lockwood Dam by owners FPL Energy and Merimil Limited Partnership, said Robert Richter of Belgrade, senior biologist for FPL Energy.

When the lift is completed, sea-run species will be trapped, sorted and trucked to lakes and ponds upriver, extending the flow that opened with the breaching of the Edwards Dam.

“Sometime in late April, early May we will start seeing some alewives and we could catch some salmon,” Richter said. “Then, toward the end of the alewife run, the shad starts to show up, that could be some time in June, and we’ll run the fish lift through early July … then, as the water cools down, we’ll run it again in the fall to catch salmon.”

At the Benton Falls Dam, the $1 million lift will be ready by the end of April, according to operations manager Gary Robinson.

He said the elevator-style lift raises the fish in a collection chamber from the main body of the Sebasticook River to the headwater, or the upstream end of the dam.

The lift rises between 28 and 32 feet depending on the time of year and the volume of river flow.