RICHMOND — Work on the new Richmond-Dresden bridge is starting, but a significant archaeological dig on one side of the bridge will be allowed to continue for at least another month.

Construction-related work is starting on the Dresden side of the bridge, allowing archaeological work at the former site of two colonial forts on the Richmond side to go on. That’s good news to archaeologists who feared they would be forced off the site before they could documented fully the rich source of new historical information they and volunteers have been working to uncover.

“The contractor, Reed & Reed, and their soil contractor very kindly told us we’re welcome to stay on the site for a period of time,” said Leith Smith, an archaeologist with the Maine Historic Preservation Commission. “Two of us and volunteers will be working at the fort site through July, and possibly into August. They’re going to be starting work on the other side of the river, the Dresden side. So that helps us. We’re very, very relieved.”

Workers preparing for construction of a new bridge have found not only parts of the original 1720s and 1740s Richmond forts, but the roof of the blockhouse of Fort Halifax, which was washed away from its site in Winslow in the flood of 1987.

Among the more interesting recent discoveries at the dig site are pieces of a cannon that Smith said dates to the original Fort Richmond, built in the 1720s.

“We’re pretty sure the cannon may have blown up during the occupation of the early fort,” Smith said. “They fired the cannons from time to time, as salutes, or to signal Native Americans if important information had been received.”

Smith said officials have a document that lists some of the munitions at the fort in 1730, which includes two or three burst cannons.

“We have no information yet on whether somebody may have been injured when that happened,” he said of the damaged cannons. “We’re going to look into that. We’ll look for requests for compensation by family members” of anyone who may have been injured in a cannon accident.

Smith said the fort did fall under “attack” by American Indians at least twice, but said it is unclear what happened.

As ground has been dug up — by hand, shovel and even a backhoe — differences between the early 1720s fort and its larger replacement, built on the same spot in the 1740s, have emerged.

The first fort, Smith said, was a tight cluster of buildings in a small, confined area. The second was more open, with more buildings and more space between them, with a cobblestone-and-brick courtyard.

“That is in itself interesting, because the fort represents a transition from earlier fort technology, from the 1600s, coming into more of the timber-fort technology of the early 1700s,” Smith said.

The new bridge, meanwhile, will be quite a transition from the old, relatively low, roughly 80-year-old steel swing bridge, too.

The new bridge will have steel beams with concrete piers. Its peak will be about 75 feet above the river.

The current deteriorated bridge swings one section to the side to allow taller ships to pass through.

The new fixed bridge is designed to be tall enough for Coast Guard ice-breaking vessels to pass underneath.

Nate Benoit, project manager for the state Department of Transportation on the bridge replacement project, said survey layout at the site already has begun.

The old bridge will remain in place and be used until the opening of the new bridge, projected to be in July 2015. Having the old bridge remain while the new bridge is built just north of it means only a few traffic disruptions are expected during construction.

“We are building a parallel bridge and traffic will be maintained throughout,” Benoit said by email. “We will have one lane of alternating two way traffic on the approaches for a short period of time. This will not occur until maybe the fall of 2014.”

Benoit said the project also should have little effect on boaters in the Kennebec River below. The channel will need to be closed when the old bridge is removed and when steel is set for the new bridge.

Coffer dams will be installed in the river for part of the project. Some pile driving — which can create noise — will occur for some of the substructure of the bridge, but Benoit said that work would not take place at night.

The project was initially projected to cost as much as $25 million, but bids came in lower than expected, according to Ted Talbot, spokesman for the DOT.

The winning bidder for the job, Woolwich-based Reed & Reed, bid $14.3 million. With engineering costs included, the overall cost, Benoit said, should be about $18.6 million.

The project is funded partially by a $10.8 million federal grant.

Smith said the home of Paul and Jill Adams, where the Fort Richmond dig has taken place in the front yard, will be removed to make way for the bridge, as will a cape on the Dresden side of the river.

He said the Adamses’ home will be used as a field office before it is removed.

Last week a crew of 26 high school students assisted at the Fort Richmond dig, through a Maine Humanities Council program. Other paid archaeologists have been assisting at the site this summer, but Smith said there’s only enough funding for him and one other state archaeologist, Bill Burgess, to continue working there. However, they hope to continue to be assisted by volunteers. Volunteers interested in helping may contact Burgess at 737-2509 or by email at william.burgess@maine.gov.

Smith said the dig has proven to be extraordinarily productive, revealing structural details of the two forts and about 250,000 artifacts, including European ceramics, American Indian items, tools, and a winged cherub religious icon.

“We’re continuing to find more artifacts,” Smith said, “which will help us understand the life of a soldier, of the people in the fort.”

Keith Edwards — 621-5647
kedwards@centralmaine.com