ELLSWORTH – Ninety years of sediment on the Union River bed soon will find a new home as barges Thursday prepared to dredge the three-mile federal channel that runs from Weymouth Point to the town dock off Water Street.

The project will cost about $1.5 million and is funded by a federal appropriation to the U.S. Army Corps of Engineers. Burnham Associates of Salem, Mass., will do the work.

“The process will be very similar to cranes on land that pour dirt into dump trucks,” Burnham Associates project engineer Chris Bonn said Thursday.

Bonn said the process would involve the two barges: one with a crane that picks up the sediment off the river bed; and a second one, called a scow, that will transport the sediment, or “spoils,” to an area near Tupper’s Ledge, about 11/2 miles from the mouth of the river.

Coincidentally, Tupper’s Ledge is the same area where spoils were deposited the last time the Union River was dredged – 1911. A number of lumber mills that once operated on the edge of the river used it to dispose of sawdust. Bonn said he expects the dredge will encounter much of that old waste, in addition to mud and natural silt.

“Dredging is done as needed, and the Union River is really a maintenance job, as it has been dredged before,” Bonn said. “In areas like Charleston, South Carolina, and Baltimore, Maryland, the respective harbors have to be dredged nearly every day of the year because of all the large commercial ships that do business in those areas.”

While the Union River still won’t be accessible to large commercial ships, the planned removal of roughly 60,000 cubic yards of sediment is supposed to increase the current 21/2-foot depth in the channel during low tide and to improve accessibility for some smaller watercraft.

“We’ll be digging down to give 5 to 6 feet of clearance, even in low tide,” Bonn said. “Some commercial fishing vessels and some of the smaller yachts need only 4 feet of clearance.”

With those improvements in mind, Town Manger Tim King is optimistic about the long-term effects on the community.

“Downtown business is one of the keys to economic development here in Ellsworth,” King said Wednesday. “And dredging is really the lynchpin to opening improvements on the waterfront. It will allow boats of a larger size to be moored in the harbor.”

The city of Ellsworth will share the cleanup costs by financing additional dredging set to begin as soon as the current project has finished in the federal channel.

“The city’s portion of the dredging will include the perimeter of the turnaround area in the harbor at the end of the federal channel,” King said.

According to King, the city’s portion of the project will cost $250,000 to $300,000.

“There was $100,000 set aside for the dredging in last year’s budget, and the remaining balance will probably come from a combination of funds from next year’s budget and a small short-term loan to be repaid in 2003,” King said. “We may also use a different contractor for our portion of the project.”

Dredging can take place only between Nov. 1 and April 15 due to a state mandate imposed by the Department of Environmental Protection and the Department of Marine Resources.

By restricting dredging to winter months, the effect will be minimal on spawning fish, such as alewives and Atlantic salmon, that come up the river every spring.