Housatonic Rest of River — Although a General Electric Company (GE) representative outlined its plan for Reach 6 of the Housatonic Rest of River remediation that includes Woods and Valley Mill ponds, some details of that facet of the decade-plus project will need to wait until the reach’s final plan is released next year.
“This is a conceptual design, so this is kind of a proof of concept, looking at what could be done, and we’ll get into more detail as we get to the final design,” GE Senior Project Manager Kevin Mooney said at a January 15 public meeting on Reach 6 held via Zoom.
Public input on the Reach 6 plan ends February 3 and can be submitted to R1Housatonic@epa.gov.
Following decades of contaminating the Housatonic River from its Pittsfield plant with polychlorinated biphenyls (PCBs), or toxic chemicals that don’t break down, GE executed a 2020 agreement with the Environmental Protection Agency (EPA) and representatives from five affected Berkshire County towns outlining the remediation of the waterway. That plan provided for the most-concentrated PCB materials to be sent to a landfill out of the area while the least-concentrated materials would be deposited in an Upland Disposal Facility (UDF), or toxic-waste landfill, in Lee.
Mooney’s hour-long presentation offered highlights of the project that will remove more than 490,000 cubic yards (cy) of sediment, with much of that dredged material expected to be transported using hydraulic pumping to the UDF in Lee. About 8,610 cy of higher PCB-concentrated materials are slated to be sent by rail to an off-site landfill.
Mooney’s slide presentation can be found here.
Defining Reach 6
Reach 6 includes Woods Pond at 53.6 acres, the outlet channel of Woods Pond at about 3.7 acres, and five floodplain areas that incorporate two vernal pools. An additional area, “Headwaters,” is a transition zone of 12.6 acres, and its remediation will be performed with Reach 5C.
Valley Mill Pond’s 4.6 acres is also in Reach 6, on the eastern side of the river and south of Woods Pond Dam. Its remediation will use hydraulic pumping within the same system as Woods Pond.
According to Mooney, in most of Reach 6’s floodplain, PCB levels are below the EPA standards for acceptability and soil remediation is required in two areas of about 400 square feet. The two vernal pools in the area don’t require remediation, he said, as they are below the EPA limits for vernal pools.
All sediment removed from Woods Pond will be taken to the UDF as sampling has shown the “average” PCB concentration to be at about 3.5 milligram per kilogram (mg/kg) below the 100 mg/kg standard set by the EPA. For Valley Mill Pond, historical sampling from 2001 and supplemented with additional data from 2023 shows some materials will need to be transported to an off-site facility. Floodplain soil will be evaluated to determine the average PCB concentration, with the dredged material taken to the UDF if it is at a concentration level of less than or equal to 50 mg/kg and off site if greater than that value.
Remediation efforts in Reach 6 will take about three to four years to complete and are expected to be performed in parallel with upstream remediation in Reach 5A. Mooney said the capping of Reach 6 will be delayed about five years after that project finishes to allow for the upstream remediation in Reaches 5A, 5B, and 5C to finish.
Plan details
According to Mooney, sediment in Woods Pond will be hydraulically dredged up to six feet below the Woods Pond Dam crest, with possibly an extra foot to account for a cap that will serve to protect erosion on site and prevent any remaining contamination. The process involves dislodging the sediment and sucking the matter along with the river water into a pipeline using a pump. This creates a slurry that, once it reaches the UDF, will be dewatered and treated at the UDF’s on-site water-treatment facility before it is discharged back into the Housatonic.
However, detailed information for Valley Mill Pond’s remediation will come later once PCB sampling in the area and surveys have been conducted, actions that will “determine the type and extent of remediation necessary.”
Mooney said GE sampled the sediment and floodplain soil in Woods Pond and Reach 6 in the fall of 2023, compiling that information into a report submitted to the EPA on October 31. Those investigations showed that about 11 endangered species have habitat in the area, he said, with details about mitigation efforts impacting those species reserved for Reach 6’s final design.
A facility to assist in the dredging and for handling materials will be constructed on the southern shore of Woods Pond, with a bulkhead and boat launch for pond access. A rail spur and loading/unloading area will be built just west of Woods Pond.
The final design of Reach 6 will include standards for the area’s air quality, noise, odor, and lighting, with air-quality and noise monitoring during the project used to determine if those standards have been violated.
Removal and transport by the numbers
Mooney illustrated how much area is estimated to be remediated within Reach 6. The total amount of area to be removed from Reach 6 is estimated to be 493,320 cy, or about 61.5 acres, with most of that coming from Woods Pond. All materials to be removed from Woods Pond, about 461,000 cy or 53.6 acres, will be disposed of at the UDF, as well as the Outlet Channel sediment’s 20,000 cy.
Out of the 12,300 cy, or 4.2 acres, of sediment anticipated to be removed from Valley Mill Pond, about 3,700 cy of it will be taken to the UDF, and the majority, or 8,600 cy, will be disposed of out of the area.
At an estimate of only 20 cy, not much of Reach 6’s floodplain soil will be removed, with that disposal split evenly between the UDF and an out-of-area landfill.
Push for shorter cleanup period
Led by Dr. Charles Kenny, chair of the Tri-Town Health Department representing Lee, Lenox, and Stockbridge, meeting attendees repeatedly pushed EPA officials and Mooney for ways to shorten the timeline for Reach 6’s remediation, including the reason behind the five-year gap between completing that Reach and capping Woods Pond. “I want to address the issue of how long this is taking,” Kenny said. “The total project is quite long, and so I’m looking at how we might reasonably speed it up.”
Upon questioning by Kenny, Mooney responded that, per this conceptual design, the estimated time for the project anticipates two hydraulic dredges to be used simultaneously at Woods Pond, five days a week, for 10 to 12 hours daily. Kenny pointed out that the project could be hastened if officials doubled the number of dredges to four to be used at one time, possibly cutting the three-year length of the project to a year and a half.
Mooney said that all the material from Woods Pond must be pumped to the UDF, limiting how much material could be processed at the landfill. Kenny inquired about whether the result would differ should an auxiliary dewatering and water-treatment plant be placed elsewhere, such as at Columbia Mill, so material from another reach, Reach 5C, could be processed at the same time.
“I’m not sure if it’s going to be a viable idea that we then expand the area down to Columbia Mill,” Mooney said. “It’s far away from the operations center, and there potentially could be a limit of space and infrastructure and also contractor capabilities if this were done.”
Woods Pond “has by far the highest volume, and it’s relatively the easiest to pump out,” according to EPA Project Manager Dean Tagliaferro. “To get the mass removal out as quickly as possible, we went back and forth as to where GE could have two crews and thought, ‘5A and Woods Pond,’” he said. “That’s the two largest areas of volume… we went where the largest volume was to get as much out of the river as possible. Ideally, you could work all eight reaches at the same time but, as [Mooney] said, I think there’s a feasibility limit there.”
Since the material removal will occur prior to completing the removal and backfilling of upstream reaches, Tagliaferro said Woods Pond can’t be capped until all upstream reaches are capped. Otherwise, the clean cap would risk being contaminated again, he said.
Pittsfield’s Kaitlyn Pierce advocated that research shows no level of PCB exposure is safe, while the plan allows for leaving lower levels of PCB concentration in the waterway and floodplain. Tagliaferro responded that the EPA established its cleanup process following 15 years of research into a human-health assessment standard that evaluates the risk at such sites. “Very few chemicals have zero risk at any concentration, so EPA’s regulations and guidelines have what they have determined, and others have determined… [to be] acceptable risk ranges,” he said. Those ranges apply to every Superfund site and are based on factors such as how often people are in contact with the contaminant and lifetime cancer risks, eventually becoming the performance standards GE must meet in this project, Tagliaferro said.
“Far and away the highest risk to human health is consumption of fish,” he said. “So, that is and will be our main goal for the remediation.”
EPA Remedial Project Manager Josh Fontaine added that the site will continue to be monitored after the remediation has ended, ensuring samples are within that risk range and the cap is performing.
Charles Cianfarini, interim director of the Citizens for PCB Removal, inquired about the rate of water flow during the remediation process, voicing concern about the river running dry as the waterway is dredged. EPA Remedial Project Manager Josh Fontaine answered that the river water will be replaced once it is treated at the UDF treatment facility, backfilling the removal, and Mooney replied that the rate at which the water is removed is lower than the rate of flow as the water is replaced.
After the final Reach 6 plan is released, EPA and GE officials said their representatives will hold another public meeting on that proposal.
