Posted on October 26, 2017
By Bob Beckstead, Watertown Daily Times
Design work for Arconic’s cleanup of the Grasse River will continue through 2018 and, although a “minimal amount” of contaminated sediment is being removed from the Grasse River this year, removal of the remainder of the contaminated sediment probably won’t begin until 2019, according to an official from the U.S. Environmental Protection Agency.
Young Chang, EPA remedial project manager, said that once construction starts for the remainder of the river, the clean-up process will take about four years.
She said the design for the cleanup is about 65 to 70 percent complete right now.
“The design is still ongoing,” she said.
Dan Casey from Arcadis, a consulting firm working with Arconic, said there has been plenty of activity at the site, which is near County Route 42 and the state Route 131 bridge that crosses over the Grasse River.
“What you’re seeing right now as you drive by is an awful lot of dirt has been moved,” he said.
Mr. Casey said there’s still much work to do yet, including the construction of a bulkhead. That’s where barges that are bringing impacted sediment will tie up and off-load the material. Clean barges will be used to transport clean capping material. Impacted sediment will be processed before eventually being taken to the landfill on Arconic property.
“At this point the majority of the site work is near complete. The contractor is doing some touch-up work,” such as final grading on roadways and electrical and underground work, Mr. Casey said.
Cleanup of the river will be done through dredging and capping of contaminated sediment in a 7.2-mile stretch of river. About 109,000 cubic yards of sediment will be dredged from near-shore areas of the river. In the river’s main channel, about 59 acres of sediment will be covered with an armored cap and another approximately 225 acres of contaminated sediment will be capped with a mix of clean sand and topsoil to isolate the contamination from the surrounding environment.
Work this year has included the construction of a staging area to unload sediment dredged from areas near the shore of the river. The area will also be used to stage and load clean materials that will be used to backfill dredged area sand to cap the river bottom during the in-river cleanup.
Source: Watertown Daily Times
