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The First Phase of Dredging

In its 2002 Record of Decision for the Upper Hudson River, EPA conceptualized the dredging project in two phases. The first phase of the project involved the construction of a processing, treatment and transportation facility to support the project, and the first year of dredging activities. The second phase of dredging, set to begin in 2011, encompasses all future years of dredging.

Phase 1 of the work began on April 23, 2007, when GE’s contractors broke ground on a 110-acre parcel selected by EPA for the needed support facilities. The site, located in Fort Edward, N.Y., sits between the New York State Champlain Canal and an active rail line owned by Canadian Pacific Railway. The property, which had previously been used for agricultural purposes, had no electrical or water service, no road access, no rail yard and no wharf. 

GE selected an Upper Hudson region firm, the D.A. Collins Construction Co. of Mechanicville, Saratoga County, to develop the site. Another New York firm, Sevenson Environmental Services, Inc., was selected to construct the processing and dewatering facilities at the site. A third company, RailWorks Track Services, Inc., was selected to develop the rail facilities.

During the 18 months needed to construct the facilities:

• A new two-mile paved road connecting the property to Route 196 in Kingsbury, N.Y., was constructed;
• A bridge over the Feeder Canal and five culvert crossings over Bond Creek and the Champlain Canal diversion channel were built;
• Six miles of perimeter and interior security fencing was installed;
• Approximately 150,000 cubic yards of soil were excavated, primarily in areas near the rail yard, and 90,000 cubic yards of structural fill were placed;
• 2.4 million square feet of a geomembrane liner was welded together and installed as a protective barrier underneath areas where dredged sediments would be handled or processed;
• Approximately 3,000 linear feet of water line and 150 feet of electric conduit and manholes were installed;
• Seven miles of railroad track was installed, including repair and inspection tracks and two controlled switches to the existing rail line;
• A 1,500-foot terminal wharf on the Canal was built for barge staging and unloading; and,
• The Champlain Canal was widened by 65 feet to ensure non-project-related boats could successfully navigate through the Canal, around project barges.

Three other riverside parcels were developed to support the project: an equipment staging area on U.S. Route 4 in the Town of Fort Edward, NY; a work support marina in Moreau, N.Y., with docking for more than 30 survey and support boats; and a neighboring staging area for backfill aggregate materials.


Three contractors were selected by GE to implement Phase 1 dredging: Cashman Dredging & Marine Contracting Co. LLC, based in Quincy, MA, was selected for in-river dredging work; The Shaw Group, Inc., of Baton Rouge, LA, was chosen to operate the unloading wharf and processing facilities; and Penguin Logistics LLC, of Cranberry Township, PA, was selected to operate the rail yard.

Before dredging began, crews removed trees and vegetation from the river banks that hung over the areas to be dredged. In addition, a temporary structure composed of rock was built in the eastern channel of Rogers Island to minimize water flow through the channel.

Phase 1 dredging was conducted over a six-month period from May 15, 2009, through October 27, 2009. Work was conducted around Rogers Island in Fort Edward, N.Y., and in the eastern channel of Griffin Island, located approximately three miles downstream. Crews worked 24 hours a day, six days a week, to remove nearly 290,000 cubic yards of sediment from the river.

Mechanical excavators equipped with environmental clamshell buckets were used to remove river sediments. The buckets were guided by global positioning systems (or GPS) to accurately remove those sediments targeted by EPA for dredging. The excavators were mounted on flat deck barges, which were anchored in place until dredging in that area was completed. As many as 12 dredges operated in the river at the same time.



After buckets were filled with sediment, the dredge operator unloaded the material into 195-foot-long hopper barges. Once filled, these barges were pushed by tugboats through Lock 7 to the processing and transportation facility located approximately one mile upstream. A fleet of 17 tugboats was used to move the barges around.


To ensure barges waited safely to traverse Lock 7, GE installed four mooring posts in the river south of the lock. In addition, a turning dolphin was installed at the lock to help turn barges as they approached and left the narrow passageway.


After dredging was completed in a particular area, sampling was performed to assess whether PCB levels in the remaining sediments met EPA’s standard. Depending on these results, more dredging was performed, or clean sand and gravel or capping material was placed in the area. All told, approximately 150,000 tons of rock and dirt was used for backfilling and capping during Phase 1.


Nearly 650 hopper barges filled with sediment were transported to the processing facility for unloading. Large debris was removed first and placed in temporary staging areas on the site for transport off-site. Watery sediment in the barges was unloaded by a 5-cubic-yard bucket and placed in a rotating trommel screen that separated out debris, rocks, gravel and other large material. Water was sprayed onto the material as it moved through the trommel.

The material, now a slurry, was pumped into hydrocyclone units, which separated sand from the slurry. The slurry then moved into a gravity thickener — an 80-foot-diameter, aboveground tank. Inside, compounds were added that caused larger sediment particles to clump together (or thicken) and settle to the bottom of the tank while water remained on top.

The thickened slurry was pumped from the gravity thickener to smaller tanks and then to filter presses housed inside a 41,000-square-foot dewatering building. The presses, each weighing 140,000 pounds, were situated on 18-foot stands. Additional water was pressed from the slurry, making a “cake” out of the dewatered sediment. This cake would fall off the presses into roll-off boxes situated beneath each press.

The cake was temporarily staged inside one of two 400-foot-long structures. Then, it was loaded into railcars lined with plastic wrappers for transport to a hazardous waste storage facility in Texas.

The more than 95 million gallons of water generated during processing was treated at an on-site, 27,000-square-foot water treatment plant. After sampling to verify the water exceeded New York State's standards, it was discharged to the Champlain Canal.