PROSPECT, Maine — The Friends of Fort Knox on Sunday reopened a section of the historic fort housing an above-ground cistern that has been closed to the public for decades.

The cistern — a reservoir for storing water — and adjoining enlisted-men’s quarters were refurbished this summer as part of the Friends group’s “Century and a Half” masonry project — work on the fort began in 1843 and was completed in 1869. Orrington mason Joe Bowley repaired loose and falling bricks on the walls of the cistern and quarters and on vaulted ceilings in both rooms. Bowley also replaced and repaired mortar in areas of the walls and ceilings.

“The bricks were falling,” Bowley said. “We lost one big chunk.”

Leon Seymour, the executive director of the Friends group, said they were concerned about bricks falling on people’s heads. That is why the area had been closed to the public for at least two decades, he said.

Many of the fallen bricks had been taken from the fort, and one whole section of the wall of the enlisted-men’s quarters was missing, Bowley said. He was able to draw on stores of old bricks that had been salvaged from around the fort, but many were different sizes and textures than those that remained in place. That posed a challenge for the mason, but the biggest challenge, he said, was a force of nature.

“We were fighting gravity,” Bowley said.

When the cistern and the quarters were built, the builders would have used forms to create the vaulted ceilings, he said. He had to use a 2-by-4 support system to hold sections of brick in place while the mortar dried.

“It was quite a challenge,” he said.

Bowley and his crew spent much of the summer working on the areas in most need of repair, and worked about three weeks on the cistern and quarters areas.

Tim Hall, regional manager for the Bureau of Parks and Lands which oversees the historic site, said the cistern, one of four in the fort, was an important feature in the design of Fort Knox and other forts which could provide water to the defenders in the event of a siege.

“The Friends of Fort Knox have used their own money to bring this area back into public view so that we can better understand the history and how the fort worked,” Hall said.

Also present for the ribbon cutting were Chris Popper, chairman of the Friends of Fort Knox; Sen. Carol Weston, R-Waldo County; and fort manager Mike Wilusz.

The cistern, and another aboveground cistern that is bricked in, is an unusual feature, according to Seymour.

“You won’t see them anywhere else,” he said.

The restoration of the cistern is part of the first phase of the masonry project, which is expected to continue through spring. Bowley has provided the Friends with a 10 percent discount on his work, which has kept the costs reasonable, Seymour said. The group still expects to spend about $75,000 on Phase I of the project by the time it is completed.

Phase II of the project will involve identifying the major areas of masonry work that might cause safety concerns in the fort, and Phase III will include repairing the rest of the masonry work around the fort.

“We want to bring the rest of the masonry up to snuff, so that it will last another 150 years,” he said.