|
by Chris Chase
Coastal Journal staff
BATH — BIW has applied for multiple permits to resume dredging operations in the Kennebec River sometime in the next few months.
According to the public notice released by the US Army Corps of Engineers (USACE), the permits are asking for permission to complete three separate projects. The first, which has been approved, is a plan to dredge 3,500 cubic yards of material from the shoreline for routine maintenance. The material will be trucked to an in-shore location that has been used by BIW in the past.
The other two projects have yet to be approved. The first is a plan to cover the riverbed with 7,020 square feet of stone in anticipation of the upcoming Brake Wheel Project, a new technology for testing ships’ propulsion systems.
The second project is a large dredging of 70,000 cubic yards of material around the BIW drydock. According to the public notice, this is to “re-establish operational depths within their drydock sinking basin.” The material will be dumped at the in-river disposal site down river of Bluff Head, where material had been dumped during previous dredging operations.
The dredging comes just over a year after the previous dredging operation on the Kennebec, in August 2011. The previous operation also moved 70,000 cubic yards of material, and dumped it in the same in-river location as the current plan. The 2011 dredging operation stirred up a bit of controversy, due to its projected environmental impact. People who depend on the river for their livelihoods expressed concern at the time that the dredging would hurt wildlife and disrupt their businesses.
According to Jay Clement of the USACE, this project will have much less impact on the environment, primarily due to it being done in the winter. Typically, dredging projects occur in the winter to minimize their impact to the wildlife of the region, unlike 2011’s dredging.
“That was a unique case,” said Clement of the August 2011 project. “It was not in the time frame that we typically do dredging in the Kennebec.”
The 2011 project came about due to the passage of the USS Spruance, DDG-111, a new destroyer constructed by BIW.
“The dredging that took place a year ago was to clear the navigation channel out,” said Jim DeMartini, manager of communications and public relations for BIW. “What we’re doing today is primarily maintenance activity.”
Although concerns have been raised in the past about the viability of continuously using the in-river disposal site, according to Clement, keeping the material in the river is essential.
“The Maine Geological Survey has been adamant about keeping the sand in the system,” said Clement.
Although taking the material and moving it out to sea would eliminate the need to dredge as often, the impact of such a project could be drastic.
“You’re potentially taking it out of the system and it can no longer play a role,” said Clement.
According to Clement, the strong river and tidal current interactions present in the Kennebec move a massive amount of material back and forth along the bottom of the river. This movement is what necessitates the regular dredging of the river by BIW. Even though removing that sand from the system entirely would save money in the long run, the environmental impact is impossible to gauge unless the sand is actually moved. The problem is, once you move the material out of the system, getting it back into the river would be impossible.
According to Clement, the material that is being moved around has been monitored and tested to ensure that the impact of the current project will be minimal.
“There was updated sampling of the material to be dredged and material at the disposal site,” said Clement. “Based on past experience, the disposal site’s sediment depth tends to move in river currents.”
In addition to the material being moved to the in-river site, the material being trucked off site to an in-shore location has also been monitored to ensure as minimal an impact as possible.
“The volumes of material have been historically very low,” said Clement. “They [BIW] have dump sites available to them approved by the Maine DEP.”
The dredge material from this project will be sent to North Bath, at a site owned by Crooker Construction.
The one piece of the project that will be new, the establishment of a layer of rock on top of the riverbed, is aimed at providing scour protection for the riverbed during the upcoming Brake Wheel Project.
The project is a way to test the propulsion systems of ships while they are tied up to a dock, using a special prop.
“It enables them to test the propulsion systems without generating the same force as a normal prop,” said Clement. “The alternate propeller counters some of the force that’s generated and allows them to still test the engines.”
With the massive forces that the ships produce, using a normal propulsion system while the ship was tied would end in disaster and the destruction of a great deal of BIW property.
“The Brake Wheel allows us to torque up the engines without moving the ship,” said DeMartini.
The project itself is testing the propulsion system on the DDG-51 ships that BIW is currently working on. DeMartini compared it to the propellar on an airplane, which can be articulated to allow it to either sit still on the runway or provide thrust.
Even with the new technology, however, there is still a worry that the massive forces involved could scour away sediment from the riverbed and damage the pier’s foundation structure.
“By placing this stone, they ‘armor’ the bottom against this scour,” said Clement.
For now, the permit approval process is still ongoing, and the USACE is reviewing public comments that have been submitted. The decision on whether or not the permits will be issued will come in a few months time. Based on nearly identical projects carried out in the past by BIW and the timing of the projects, the likelihood of the projects not being approved is slim.
“We’re right within the approved window for dredging this time around,” said DeMartini.
 |
Show/hide comments
Show/hide comment form