The harbor in Milbridge, which sits in the mouth of Narraguagus River, was dredged 15 years ago but it already has to be done again because of a bridge replacement project, according to a town official.
The Maine Department of Transportation denies the claim.
The town marina sits just to the east of where a causeway carries Route 1A over the river. Ever since Maine DOT replaced two bridges on the causeway in the late 2000s, the river’s flow under the bridges toward the marina has been different, causing sediment to build up much faster on the harbor bottom than it did before, said Lewis Pinkham, Milbridge’s town manager.
Because of the buildup, the U.S. Army Corps has approved another dredging project for an approximately mile-long section of the river, between the bridge and where the river opens up into Narraguagus Bay, Pinkham said. The $3.9 million project funded by the federal agency will entail a survey and dredging of that portion of the river in the coming years.
Prior to being dredged in sections from 2004 to 2007, the river had not been dredged since the 1950s. But since the bridges were replaced in 2008, silt has quickly piled up in the places that were dredged, including one area where 9 feet of sediment accumulated in just five years, Pinkham said.
“The new bridge abutment changed the flow, causing the sediment to fill in way more than it should,” he said. “The Army Corps said they had never seen a channel fill so quick.”
Whether the new dredging project will include measures to prevent or reduce additional sediment buildup was not clear Thursday. Pinkham said he did not know details of the scope of the project.
The Maine DOT denies that the bridge projects are the cause of the silt though.
“Study and calculations on current velocity were done prior to construction because of the possible effects to the native salmon on the Narraguagus River,” said Paul Merrill, director of communications for the Maine DOT. “[T]he velocities changed slightly, but not enough to affect salmon, therefore the thought that the new bridges were the cause of the siltation problem is very unlikely.”
Material from the prior dredging was barged out to Narraguagus Bay and disposed of next to Douglas Island. Where dredged material will be disposed of during the pending project has not been determined.
Pinkham said the dredging project is needed because the town marina, located off Bay View Road, is “very busy.” It is used heavily by lobster fishermen — many of whom have boats bigger with deeper keels than those commonly used in the 2000s, he said — and also by boat builders, recreational boaters, and others who come and go from local islands.
The state’s lobster fishery is by far the biggest in Maine, and lobster fishing both in Milbridge and in Washington County in general has been on the rise since the local harbor was last dredged.
From 2004 through 2020, the percentage of Maine lobster that was harvested in Washington County increased from 11 percent to 20 percent, according to the Maine Department of Marine Resources. For the last three of those years, from 2018 to 2020, Milbridge ranked among the top 10 busiest fishing ports in the state. Port-specific fishing data for 2021 is not yet available.
“The boat ramp is very, very active,” Pinkham said.
Pinkham said the Army Corps has yet to solicit bids for the dredging work, so it is too early to know when the work will be done.