PB98-963127
EPA541-R98-118
March 1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Beacon Heights Landfill
Beacon Falls, CT
9/9/1998
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DECLARATION
FOR THE
EXPLANATION OF SIGNIFICANT DIFFERENCES
SITE NAME AND LOCATION:
The Beacon Heights Landfill Superfund Site is located in the town of Beacon Falls, Connecticut.
STATEMENT OF PURPOSE:
This decision document sets forth the basis for the determination to issue the attached
Explanation of Significant Differences (BSD) for the Beacon Heights Landfill Superfund Site in
Beacon Falls, Connecticut.
STATUTORY BASIS FOR ISSUANCE OF ESD:
Section 1 17(c) of the Comprehensive Environmental Response Compensation and Liability Act
(CERCL A) requires that, if any remedial or enforcement action is taken under Section 1 06 of
CERCLA after adoption of a final remedial action plan, and if such action differs in any
significant respects from the final plan (i.e., scope, performance or cost), the United States
Environmental Protection Agency (EPA) shall publish an ESD and the reasons such changes
were made. Current EPA guidance (OSWER Directive 9355.3-02) further provides that issuance
of an ESD is appropriate where the Agency determines the need for changes to the Record of
Decision (ROD) which are significant but which do not fundamentally alter the overall remedy.
In the present case, because the required adjustments to the ROD do not fundamentally alter the
selected remedy for the Site, this ESD is being issued properly.
In accordance with section 177(d) of CERCLA, this ESD will become part of the Administrative
Record which is available for public review at both the EPA Region I Record Center in Boston,
Massachusetts and the Clerks Office in the Town Hall in Beacon Falls, Connecticut.
DECLARATION:
For the foregoing reasons, by my signature below, I approve the issuance of an Explanation of
Significant Differences for the Beacon Heights Landfill Superfund Site in Beacon Falls,
Connecticut, and the changes stated therein.
Date Patricia L. Meaney, Director
Office of Site Remediation and Restoration
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EXPLANATION OF SIGNIFICANT DIFFERENCES
BEACON HEIGHTS LANDFILL SUPERFUND SITE
BEACON FALLS, CONNECTICUT
I. INTRODUCTION
A. Site Name and Location
Site Name: Beacon Heights Landfill Superfund Site
Site Location: Town of Beacon Falls, Connecticut
B. Lead and Support Agencies
Lead Agency: United States Environmental Protection Agency (EPA)
Support Agency: Connecticut Department of Environmental Protection (CTDEP)
C. Legal Authority
Under Section 117(c) of the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA), Section 300.43 5(c) of the National Contingency Plan
(NCP) and EPA guidance (OSWER Directive 9355.3-02), if any remedial or enforcement
action is taken under Section 106 of CERCLA after adoption of the Record of Decision
(ROD), and if the United States Environmental Protection Agency (EPA) determines that
differences in the remedial action significantly change but do not fundamentally alter the
remedy selected in the ROD with respect to scope, performance, or cost, EPA shall
publish an explanation of the significant differences between the remedial action being
undertaken and the remedial action set forth in the ROD and shall include the reasons
such changes were made.
D. Summary of Circumstances Necessitating this Explanation of Significant
Differences
As a direct result of events that developed after the completion of the ROD and the
Supplemental ROD, decisions were made to: change the selected location for leachate
treatment, to modify the RCRA cap design, and to require that wetlands damaged during
construction activities to be replicated on the Swan portion of the site.
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Explanation of Significant Differences September 1998
E. Availability of Documents
In accordance with Section 117(d) of CERCLA, this Explanation of Significant
Differences (BSD) will become part of the Administrative Record. The ESD, supporting
documentation for the ESD, and the administrative record are available to the public at
the following locations and may be reviewed at the times listed:
U.S. Environmental Protection Agency Town of Beacon Falls
Records Center Clerks Office
90 Canal Street Town Hall
Boston, MA 02114 10 Maple Avenue
Weekdays from 10:00 a.m. to 1:00 p.m., Beacon Falls, Connecticut
and from 2:00 p.m. to 5:00 p.m. Weekdays: 9:00 a.m. - 4:30 p.m.
(617)573-5729 (203)723-5244
II. SUMMARY OF SITE HISTORY, ENFORCEMENT HISTORY AND SELECTED
REMEDY
A. Site History
From the 1920's until 1970 a small portion of what is now known as the Beacon Heights
Site was known as "Betkoski's Dump" and consisted of approximately 6 acres of active
dumping and open burning in the northwestern corner of the existing Site. During this
period of operation, there were general complaints and concerns, due to fumes, smoke,
and blowing litter. The Site was not regulated by the State until 1970.
In 1970 Beacon Heights, Incorporated (BHI) purchased the Site, which included the
Betkoski Dump area. BHI and its owner, Harold Murtha, owned and operated the Site as
Beacon Heights Landfill and expanded the landfill area to approximately 34 acres. Soil
available on the Site as a result of this expansion was used as cover material for the
landfill. Wastes were placed directly onto bedrock and covered with soil, and waste
materials were no longer burned.
A landslide of soil and buried waste occurred on the northwestern side of the landfill in
1972 due to both landfill operations and the changed surface and groundwater patterns
from construction of an on-Site access road. This landslide created groundwater and
leachate discharge points in the northern and northwestern areas of the landfill. Several
of these discharge points still persist in the former landslide area.
From 1973 until the Site closed in July 1979 specific areas or cells were used for the
disposal of various waste materials rather than placing waste directly onto bedrock.
Cover material was placed over all working areas.
In 1977 the Connecticut Department of Environmental Protection (CTDEP) approved the
spreading of wastewater sludge from the Naugatuck municipal/industrial wastewater
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Explanation of Significant Differences September 1998
treatment facility over covered areas of the landfill. These activities continued until the
summer of 1984.
B. State Response History
The State of Connecticut began regulating the Site in 1970. In 1972 and 1973 BHI was
ordered by CTDEP to develop plans to prevent pollution from the landfill from entering
the surrounding ground water. An engineering report was subsequently prepared for BHI
that provided data and information for implementing corrective actions. As part of the
study, borings were installed around the site for collection of subsurface data.
CTDEP attempted to close the landfill and regulate industrial liquids and chemicals
disposed of at the landfill by issuing additional orders to BHI in 1975 and 1976. These
orders cited contamination of well water and Hockanum Brook tributaries as a result of
landfill operations. BHI submitted a second engineering report describing an improved
landfill operating plan but not including a groundwater monitoring plan.
These activities culminated in a Consent Order between BHI and CTDEP to close the
landfill facility by July 1,1979. This Consent Order was signed on June 20, 1979 and
entered as a final Order of the Connecticut Commissioner of Environmental Protection on
July 24, 1979. BHI complied with the Order and the landfill was closed in July 1979.
EPA sampled forty-four residential wells along Skokorat and Blackberry Hill Roads in
August and September 1984. Samples were analyzed for Hazardous Substance List
organic and inorganic parameters. Two wells located along Skokorat Road, identified as
being contaminated, were resampled in November 1984 to verify the results. The
analytical results of the samples from these two wells revealed benzene at concentrations
ranging from 32 to 131 micrograms per liter (ug/1). Based on these analytical results,
CTDEP provided bottled water to the residents as a temporary safe drinking water
source. Other organic compounds detected in some of the other residential well samples
were below levels that would indicate health risks. To provide more data on the nature of
residential well contamination, 32 of the originally sampled residential wells were re-
sampled in January 1985. The results of this second round of sampling generally
confirmed the results of the previous samples. Benzene was detected in the same two
wells at concentrations ranging from 42 to 89 ug/1. Low levels of other organic
compounds (below Maximum Concentration Levels) were also identified in a limited
number of wells.
C. Federal Response History
EPA conducted several preliminary study/sampling activities in 1981 and 1982 to
evaluate Site conditions, to collect preliminary sample data, and to identify the potential
for immediate health risk resulting from migration of contamination from the Site. The
Site was listed on the EPA's National Priorities List on September 1,1983. As a result of
the listing, the Site became regulated under the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA).
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Explanation of Significant Differences September 1998
EPA performed a Remedial Investigation/Feasibility Study (RI/FS) at the Site from
March 1984 through April 1985 to identify the nature and extent of contamination at the
Site and to identify potential remedial alternatives. The RI/FS report was released to the
public in April 1985.
A more detailed description of the Site history leading up to the RI/FS, including a
summary of the results of the RI, can be found in Section 1 of the RI/FS Report, which is
part of the administrative record for the Site.
Based on the results of the RI/FS, EPA issued a ROD on September 23, 1985,
documenting the selected remedial actions for the Site. The remedy included:
• Excavation of Betkoski's dump and other contaminated soils and consolidation
within the main landfill prior to its closure.1
• Installation of a RCRA cap over the consolidated wastes, including gas venting
and stormwater management controls
• Installation of a perimeter leachate collection system.
• Extending a public water supply line along Skokorat Road and along Blackberry
Hill Road to service current residences.
• Enclosing the Site with security fencing.
• Installing a more extensive groundwater monitoring system.
• Collecting leachate and transporting it to a licensed wastewater treatment facility
or on-Site treatment followed by discharge to a tributary of the Hockanum Brook.
• Further studies and the preparation of a Supplemental ROD selecting the manner
and location of leachate treatment (on-Site or off-Site), the extent of excavation of
contaminated soils, and the need for air pollution controls on the landfill gas
vents.
After the ROD was signed, EPA issued an Administrative Order in October 1986 in
response to the discovery of contamination in some private residential wells and as a
precaution against further leachate migration. The order required the Potentially
Responsible Parties (PRPs) of the Beacon Heights Site to offer residences in the vicinity
of the landfill the opportunity to become connected to the municipal water supply system.
The owners of forty-nine residences opted to have their homes connected to the
municipal water system. The domestic water supply wells previously serving these
l Although the 1985-ROD and the Proposed Plan called for excavating Betkoski's dump, only a portion of
the dump area was excavated. The remaining area was included under the cap. This revision to the ROD
was further discussed in the Supplemental ROD, Section XV.
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Explanation of Significant Differences September 1998
residences were then abandoned. Six of the homeowners declined the offer and
continued to use private wells to supply drinking water.
On 14 September 1987, 32 PRPs, organized as the Beacon Heights Generators Coalition
(BHGC), entered into a Consent Decree with the United States of America. The Decree
required the PRPs to perform the remedial actions specified in the ROD, which included
pre-design studies to gather additional information regarding the Site. Because Beacon
Heights, Inc. (BHI) denied Site access to BHGC for these studies and other remedial
activities, remedial investigation work was not performed until a court order, issued in
October 1988, required BHI to provide access.
In March 1990, the BHGC submitted a final draft of the Pre-Design Studies Report to
EPA. On May 9, 1990 EPA issued a Proposed Plan for remediation of the Site. Based on
the RJ/FS, the Pre-Design Studies report, and public and State comments on the Proposed
Plan, EPA issued the Supplemental ROD on September 28, 1990.
The Supplemental ROD included an evaluation of alternatives for treatment and disposal
of the leachate collected from the Site. These alternatives consisted of: treatment at the
Beacon Falls Publicly Owned Treatment Works (POTW), treatment at the Naugatuck
POTW, trucking the leachate off Site for treatment, and treatment on Site. The
Supplemental ROD made the following modifications to the ROD:
• Contaminated leachate generated by the landfill would be transported to and
treated at the Naugatuck, Connecticut POTW.
• Soil cleanup standards were established for eight carcinogenic and nine non-
carcinogenic contaminants of concern. Soils that contained contaminant
concentrations in excess of these standards would be excavated from on-Site areas
outside the landfill cap and placed under the cap.
• Air pollution controls would not be required on the gas venting system. However,
continued monitoring of the vents would be required. The vents would be
constructed so as to allow the addition of pollution control devices should the
monitoring reveal levels of air contaminants exceeding the Federal National
Ambient Air Quality Standards, State of Connecticut Air Standards, Odor
Threshold Levels, or Hazard Limiting Values exceeding the 10"4 to 10'6 cancer
risk range or exceeding a hazard index of one.
During the fall of 1994, the owners of the six residences who had previously declined the
1986-1987 offer from the BHGC to connect to the public water supply were again
contacted. The BHGC again asked if they would like to be connected to the municipal
water supply system. Four of the six residents again declined, while the remaining two
residences accepted the offer and were connected during October 1994.
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Explanation of Significant Differences September 1998
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D. Delays, Violations and Penalties
The completion of the remedial activities at the Site was delayed by more than 24
months. The original construction schedule called for completion of the cap by 30
September 1993. The cap was not determined to be substantially complete until
December 1995. This delay was caused by many factors including:
• construction-related scheduling problems (permits, access, supplies, etc...);
• the replacement by the BHGC of the general contractor and the engineer;
• repairs to a major portion of the cap which had to be made due to questionable
installation techniques of the geomembrane;
• repairs to the cap anchor trench due to questionable construction;
, • reconstruction of runoff diversion benches due to questionable construction
techniques;
• the discovery and need to address new leachate seeps outside the leachate
collection system; and
• the discovery of additional wastes on site that had to be excavated and then
placed under completed portions of the cap.
In addition, further construction activities were undertaken by the BHGC to reduce
landfill leachate generation that extended construction activities at the site past the
December 1995 date.
Stipulated penalties in the amount of $600,000 were assessed to the Coalition by EPA in
February 1997 for failure to complete the project in accordance with the approved
construction schedule, and for violations related to topsoil placement, erosion control,
and stormwater management.
Numerous erosion events occurred at the site during the construction of the landfill due to
rain falling on the uncompleted cap. Portions of the landfill where soil had been placed
over the impermeable cap were the most susceptible. These erosion events caused
siltation in nearby wetlands, Hockanum Brook, and in some cases even the Naugatuck
River, several miles away. A total of 18 such events occurred. The cause of these
releases can generally be attributed to under-sizing of stormwater retention basins and
poor maintenance of those basins.
As a result of erosion which occurred on-Site, wetlands both adjacent to the Site,
principally on the Swan property, and other wetlands at some distance from the Site were
subjected to significant silt deposition. The BHGC was required to remove the
sedimentation deposits prior to final completion of the project.
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Explanation of Significant Differences September 1998
The Swan property, located west of the Site, had on several occasions been affected by
refuse being carried off the landfill. The most significant incident was the result of a
failure of the landfill slope that occurred when the landfill was operated by Beacon
Heights, Incorporated. A landslide of soil and buried waste occurred on the northwestern
side of the landfill in 1972. This material occupied much of the "Florida area" on the
Swan property and was subsequently removed and buried in the landfill as part of the
remediation activities. In addition, during a few of the larger erosion events, previously
mentioned, which occurred while the landfill was being capped, some refuse was carried
off the Site and onto the Swan property. This material was usually deposited in a wetland
northwest of the Site. The refuse material was removed and buried under the landfill cap
during wetland construction activities that occurred on the Swan property.
E. Summary of the Selected Remedy
The selected remedy for the Site was described in the 1985 ROD and subsequently
modified in the Supplemental ROD, issued in 1990. The overall remedy consisted of:
• Excavation of satellite areas of contamination for consolidation within the main
landfill prior to closure.
• Installation of a RCRA cap over the consolidated wastes, installation of gas
venting, and implementation of stormwater management controls.
• Installation of a perimeter leachate collection system.
• Extension of a public water supply line along Skokorat Road and along
Blackberry Hill Road to service current residences.
• Enclosing the Site with security fencing.
• Installation of a groundwater monitoring system.
• Transportation and subsequent treatment of contaminated leachate from the Site at
the Naugatuck, Connecticut POTW (the Naugatuck facility).
• Excavation of contaminated soils, located outside the main landfill, to levels
specified within the Supplemental ROD and placement under the cap
• Construction of landfill cap gas vents such that they could be augmented with air
pollution mitigating devices in the event that future air monitoring results require
such action. In addition, post-construction air quality monitoring would be
conducted on the Site at, but not limited to, the locations of each gas vent.
With the exception of the items listed in Section III of this ESD, the requirements set forth
in the ROD and Supplemental ROD were fully met during the remediation of the site.
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Explanation of Significant Differences September 1998
III. DESCRIPTION OF SIGNIFICANT DIFFERENCES
As a direct result of events that developed after the completion of the ROD and the
Supplemental ROD, decisions were made to change the selected location for leachate
treatment, to modify the RCRA cap design, and to require the construction of
compensatory wetlands. The changes made are discussed below.
1. Leachate Transportation and Treatment
Although the Supplemental ROD had identified the Naugatuck facility as the location
for leachate treatment, the leachate is currently being transported to the Beacon Falls
Publicly Owned Treatment Works (POTW) for treatment for the reasons explained
below.
Originally, the 1990 Proposed Plan outlined several options for leachate
transportation and subsequent treatment. The two best options were transportation of
contaminated leachate via a dedicated pipeline to the Naugatuck POTW for treatment,
and transportation via a different pipeline to the Beacon Falls POTW for treatment.
However, in 1989 - 1990 when the Town of Beacon Falls and the Beacon Heights
Generators Coalition (BHGC) could not reach an agreement regarding the terms for
transporting and treating contaminated leachate at the Beacon Falls facility, this
option was eliminated as infeasible. The 1990 Supplemental ROD, therefore,
required implementation of the Naugatuck option based upon strict evaluation criteria
and the unfeasibility of the Beacon Falls option.
During the development of the design of the leachate pipeline to the Naugatuck
POTW certain administrative and economic concerns related to the proposed route for
the dedicated pipeline were identified. Some of these concerns included: destruction
of retaining walls, mailboxes, and trees within the right-of-way; removal and
replacement of utility poles; removal and replacement of fire hydrants; construction
of a 50- to 60-foot long elevated brook crossing; possible interruption of railroad
traffic during construction and lack of a construction agreement with the railroad;
and, the necessity for constructing a pipeline crossing the Naugatuck River. These
difficulties would have resulted in significantly greater costs, inconveniences to the
general public, and project delays, as compared with implementation of the Beacon
Falls option.
In addition, the Beacon Falls pipeline would be considerably shorter (less than one
mile) than the Naugatuck pipeline (approximately 5 miles). Accordingly, the Beacon
Falls pipeline would have a lower propensity for leaks, clogging, and other operation
and maintenance problems. The community disruption caused by construction of the
Beacon Falls pipeline was less than that resulting from construction of the much
longer Naugatuck pipeline.
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Explanation of Significant Differences September 1998
For these reasons, the BHGC re-opened negotiations with the Town of Beacon Falls
in an attempt to reach an agreement to transport the contaminated leachate to the
Beacon Falls POTW. An agreement was eventually reached culminating with a
contract between the BHGC and the Town of Beacon Falls on August 31, 1992 for
the execution of the Beacon Falls option. The major terms of the agreement included
permission by the Town of Beacon Falls for the BHGC to construct the Beacon Falls
pipeline and to transport contaminated leachate from the Site to the Beacon Falls
POTW for subsequent treatment. Also included in the agreement was the
commitment by the BHGC to fund an appropriate upgrade of the Beacon Falls
POTW.
EPA, in consultation with the CTDEP , decided to adjust the overall cleanup plan for
the Site so that contaminated leachate originating at the Site could be transported via
the Beacon Falls pipeline to the Beacon Falls POTW for treatment and subsequent
discharge to the Naugatuck River. The shorter Beacon Falls pipeline, the upgrade of
the Beacon Falls POTW, and the shorter pipeline construction schedule that resulted
in an earlier remedial action completion date were all benefits resulting from this
change in the plan.
The BHGC procured all necessary state and federal permits and licenses, and
proceeded with construction of the upgrades necessary for the Beacon Falls POTW to
provide long-term treatment of the contaminated leachate to the levels required by
those permits. According to the Town's engineer , Fuss and O'Neill, the upgrades
were substantially complete and the expanded facility operational in June 1995.
In the short-term and prior to completion of the upgrades, leachate collected at the
Site was discharged to the Beacon Falls sewer system, treated at the POTW, and
discharged to the Naugatuck River. Discharge of the leachate to the Beacon Falls
POTW began on July 13, 1993. According to the chief operator of the POTW, from
the time leachate transportation to the Beacon Falls POTW began to the completion
of the facility upgrades, the POTW remained in compliance with its National
Pollutant Discharge Elimination System (NPDES) discharge permit requirements.
CTDEP has reported to EPA that the POTW's NPDES permit limits have regularly
been met since the time that the leachate has been sent to the plant. A Final
Pretreatment Permit was issued to the BHGC by the CTDEP on March 2, 1998,
replacing the previous Emergency Discharge Authorization Permits the BHGC had
obtained during the construction phase. Since the issuance of the final Pretreatment
Permit, the BHGC has consistently met the terms of this permit.
The adjustment of the 1990 Supplemental ROD to allow treatment of the leachate at
the Beacon Falls POTW resulted in a less expensive remedial action, created a less
adverse impact on the environment and the general public, and met the cleanup
objectives established in the 1990 Supplemental ROD. Approval of this adjustment
by EPA did not change any other requirements outlined in the 1985-ROD and the
1990 Supplemental ROD. These requirements were expected to be adhered to in the
time frames contained in the EPA approved construction schedule.
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Explanation of Significant Differences September 1998
2. Substitution of the RCRA Landfill Cap
The ROD called for capping of the landfill with a RCRA cap. The cap was designed
to prevent the infiltration of precipitation through the wastes, which would minimize
the generation of leachate within the landfill. The RCRA cap was to consist of a two-
component, low permeability cap comprised of a flexible synthetic membrane
installed on an 18-inch thick low permeability soil layer. This soil layer was required
to have permeability equal to or less than 1 x 10'7 cm/sec.
The design of the cap, prepared by Bechtel Environmental Inc., included two different
capping methods. At the top of the landfill, where the slopes were relatively flat, a
40-mil high density polyethylene liner would be placed over a geosynthetic clay liner
(GCL) consisting of a bentonite layer sandwiched between an upper and lower layer
of geosynthetic fabric. On the 3.5:1 side slopes, the geocomposite liner would be
replaced with 18-inches of low permeability soil. This soil would have a permeability
of less than IxlO'5 cm/sec. The design was approved on this basis since EPA
determined the replacement system was comparable in permeability to that originally
required in the ROD. EPA accepted the PRPs' position that the higher permeability
soil, IxlO'5 cm/sec, on the 3.5:1 side slopes would have a lower rate of rainfall
infiltration due to the slope of the cap and, therefore, would be equivalent to a soil
with 1x1O'7 cm/sec on the flat slopes at the top of the landfill.
Acquisition of a source for the low permeability soil and the ability to transport the
soil to the Site became an issue once the BHGC retained a contractor. Public
inconvenience caused by approximately 6,500 truckloads of soil being delivered to
the Site was also an issue. Consequently, BHGC proposed and EPA accepted an
alternate capping system that would replace the low permeability soil on the side
slopes. The alternate system replaced the low-permeability soil, originally proposed,
with a GCL. The landfill cap as constructed consisted of the following major features:
• Gas venting geotextile
• GCL
• Textured 40-mil HDPE geomembrane and
• Geonet composite.
The GCL provided a barrier with a permeability of 5 x 10'10 cm/s, which is three and
five orders of magnitude less permeable than the soil permeability requirements of the
top and side slopes (respectively) specified in the ROD. It was also less expensive to
install, it eliminated the high-volume of truck traffic associated with the delivery of
low-permeability soil to the Site, and it also accelerated the completion schedule by
an estimated 60 days.
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Explanation of Significant Differences September 1998
3. Construction of Compensatory Wetlands
Following extensive negotiations with an abutting property owner, Mr. Wilfred Swan,
the BHGC purchased 46 acres of the Swan property, west of the Site. These 46 acres
had been impacted by major erosion events during the time the landfill was actively
operated and during the construction of cap. The property was also affected by a
series of slope failures that had occurred prior to the capping of the landfill. During
the construction of the cap and the leachate collection system, the Swan property was
also used to store two equalization tanks that had been installed at the request of the
State of Connecticut. These tanks were intended to provide equalization of the
characteristics and rate of flow of the leachate. Several leachate overflows and spills
were documented to have occurred from these tanks. These incidents (i.e., erosion
events, slope failures, and leachate releases) resulted in the discharge of hazardous
waste to the Swan property. The waste and the contaminated soils and sediments
were removed and placed back within the landfill boundaries.
As described above, the construction of the landfill cap and other facilities associated
with the Site resulted in the disturbance of about 18 wetland areas on or adjacent to
the Site. These areas ranged in size from 500 square feet to nearly 2.5 acres. In
accordance with the Consent Decree (U.S. v. B.F. Goodrich Co.. et al. D. CT
No.87-286)., 40 C.F.R. Part 230.10 (d) and Section 404 of the Clean Water Act,
wetlands disturbed or destroyed by the installation of the remediation system are to be
replaced in kind. A total of 4.9 acres were affected by activities associated with
remediation of the Site. EPA required that 1.15 acres of compensatory wetlands be
created for every one acre of wetland destroyed. Using that ratio, a total of 5.7 acres
of wetlands were required to be created for the Site.
Initially, an attempt was made to locate the compensatory wetlands only on the
original 82 acres that comprised the Site. However, the areas that could be used for
wetlands construction were limited due to the presence of the landfill cap and leachate
collection system, topography, hydrology, soils, and the availability of surface water
and groundwater. Ultimately, a suitable area for wetland creation was located on the
Swan property. A 5.7 acre wetland was created in the area indicated at Figure 1.
Because the Swan property had been contaminated by activities at the landfill before
and during construction, and was an area in close proximity to the waste necessary for
the response action, it was within the definition of "on-site" for purposes of Sections
104, 106, 120,121, and 122 of CERCLA. See 40 C.F.R. § 300.400(e). The site
boundaries have been modified as a result of this determination, and are defined in
Figure 1: Beacon Heights Site Boundaries.
The adjustments to the Supplemental ROD set forth herein will not fundamentally alter
the overall remedy with respect to scope, performance, or cost. These adjustments will
not impact the other aspects of the original remedy.
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Explanation of Significant Differences September 1998
IV. SUPPORT AGENCY COMMENTS
State participation throughout the Remedial Action process has been extensive, and the
State, through the Department of Environmental Protection (CTDEP), has provided
comments on the matters addressed in this BSD. Those comments, which are
summarized in a letter from CTDEP to EPA dated September 4, 1998, are included in the
administrative record for this Site. In sum, the State supports the changes made to the
leachate transport and compensatory wetland construction aspects of the remedy, but has
concerns with changes to the cap design and has not concurred with the constructed cap.
V. STATUTORY DETERMINATIONS
EPA believes that the selected remedy set forth in the 1990 Supplemental ROD, with the
adjustments described in Section III, remains protective of human health and the
environment, complies with Federal and State requirements that are applicable or relevant
and appropriate to this remedial action, and is cost-effective. In addition, the revised
remedy utilizes permanent solutions and alternative treatment technologies to the
maximum extent practicable for this Site.
VI. PUBLIC PARTICIPATION
In accordance with Section 117(d) of CERCLA, the ESD and all supporting
documentation that is included in the Administrative Record for the Site is available for
public review at the locations and times listed above in Section 1 .D.
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Beacon Heights Coalition1
BEACON HEIGHTS NPL SITE
BEACON FALLS, CONNECTICUT
I ! ( I I !
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:GK>SYNTBC CONSULTANTS.
Figure 1: Beacon Heights Site as of September 1998
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