NCD079044426_20000511_General Electric Co. Shepherd Farm_FRBCERCLA RA_US-EPA Response to Comments on the Final (100%) RD RA Work Plan for Groundwater-OCR

JAMES B. HUNT JR.
GDVCRNOR
BILL HOLMAN
SECRETARY
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Ms. Giezelle Bennett
Superfund Branch
Waste Management Division
NO;• CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WASTE. MANAGEMENT
May 11, 2000
United States Environmental Protection Agency
Region TV
61 Forsyth Street, 11 th Floor
Atlanta, Georgia 30303
RE: Response to Comments -Final (100%) Remedial Design &
Remedial Action Work Plan for Groundwater
General Electric/Shepherd Farm NPL Site
East Flat Rock, Henderson County
Dear Ms. Bennett:
The Superfund Section of the North Carolina Department of Environment and
Natural Resources (NC DENR) received the document, Response to Comments -
Final (100%) Remedial Design & Remedial Action Work Plan for Groundwater, for
the General Electric/Shepherd Farm National Priorities List (NPL) Site. The
Superfund Section has reviewed this document and offers the following attached
comments.
We appreciate the opportunity to comment on this document. If you have any
questions, please feel free to call me at [phone], extension 349.
Attachment
Sincerely,
j)JZ!tfffi,,w~~
David B. Mattison, CHMM
Environmental Engineer
Superfund Section
Dis Qiftll·MOM·M
1646 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699•1 646
401 OBERLIN ROAD, SUITE 150, RALEIGH, NC 27605
PHONE [phone] FAX [phone]
AN EQUAL OPPORTUNITY/ AFFIRMATIVE ACTION EMPLOYER -50% RECVCLE.D/1 Oo/c POST·CONSUMCR P"PER
Ms. Giczcllc Bennett
May I I, 2000 • •
Page I
RESPONSE TO COMMENTS-FINAL (100'1/o) REMEDIAL DESIGN &
REMEDIAL ACTION WORK PLAN FOR GROUNDWATER
1. The Response to North Carolina Department of Environment and Natural Resources (NC
DENR) Comment 23 states that a withdrawal permit is not required. However,
conversations with Mr. Kenneth Ash, NC DENR Water Resources Division (919-715-
5443), indicate that a state withdrawal permit lli required if the recovery well systems
exceed a capacity of l 00,000 gallons per day (approximately 70 gallons per minute
continuously). Therefore, please revise Section 4.6.3 of the Final Design Report
accordingly.
2. The Response to NC DENR Comments 44, 96, 109, 136, 143, and 158 states:
"Please refer to EPA Comment 182 on the Pre-Final (90%) Remedial Design and
Remedial Action Work Plan for Groundwater which stated, "we recommend that this
RGVP be revised to include the schedule originally proposed for performance
sampling. In particular:
• All performance monitor wells should be sampled quarterly for the first
three years, semiannually for the next two years, and annually thereafter."
No direction was initially given requiring Agency or NC DENR approval to adhere
to the originally proposed schedule. Agency and NC DENR approval will be sought
to enter Exit Monitoring and Closure Monitoring."
However, this response is unacceptable. Although the proposed schedule is acceptable for
the purpose of completing the remedial design, please revise the sections referenced by the
above mentioned comments to indicate that General Electric (GE) shall seek written
authorization from the United States Environmental Protection Agency (US EPA) and the
NC DENR for all changes in groundwater monitoring frequency and that the proposed
schedule is subject to US EPA and NC DENR approval. This is consistent with remedial
actions conducted at other sites under the authority of the US EPA and the NC DENR, and
is consistent with the information provided in the Response to NC DENR Comments 85 and
87.
Ms. Giczcllc Bennett
Moy 11, 2000 • •
Page 2
The Response to NC DENR Comments 99, 100 and 101 indicate that clarification of the NC
DENR site closure protocols is required. The second paragraph of Chapter 11. 0 -Site
Closure of the guidance document, Groundwater Section Guidelines for the Investigation and
Remediation of Soii and Groundwater, Volume 1 -Sources Other Than Petroleum
Underground Storage Tanks, NC DEl\'R Division of Water Quality, May 1998, states:
"Sites that have been undergoing active remediation must show that groundwater has
been remediated to below groundwater standards. Four consecutive quarters of data
documenting no contamination above the I SA NCAC 21 standards or interim
standards while the remediation system is operational, and four consecutive quarters
of data documenting no contamination above I SA NCAC 21 standards or interim
standards after the remediation system has been shut down are required."
Please revise the sections referenced by NC DENR Comments 99, 100 and 101 accordingly.
4. The Response to NC DENR comment 102 states, "Per EPA Comment 69, references to
recovery well operation status have been deleted in the Annual Monitoring Reports; and
therefore will not be included in the Quarterly Monitoring Reports." Although other
reviewers may differ, this reviewer finds this information is useful in determining the
success/failure of the extraction system and is useful in developing system modifications and
system improvements. Therefore, please revise Section 3.1 and Section 3.2 of Appendix F
-Remediation Goal Verification Plan to include the submittal of the recovery well operation
status in the Quarterly Monitoring Reports and the Annual Monitoring Reports.
• • .UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
4WD-NSMB
Ms. Janet Boyer
EHS Manager
GE Lighting Systems, Inc
3010 Spartanburg Highway
Hendersonville, NC 28792
ATLANTA FEDERAL CENTER
61 FORSYTH STREET
ATLANTA. GEORGIA 30303-8960
April 14, 2000
SUBJ: GE/Shepherd Farm NPL Site
East Flat Rock, NC
RFGEI\/ED
APR 18 2000
SUPERFUNlJ s1:CTION
Dear Ms. Boyer:
Enclosed are the Agency's comments on the Final Remedial Design (RD) and
Remedial Action Work Plan for Groundwater dated March 2000. Please make sure
that all comments are incorporated before submittal of the final documents. All
comments must be incorporated before approval of the RD can be given. Please
submit revised documents no later than May 5, 2000. Comments from NC DENR will
be transmitted under separate cover.
If you have any questions, please do not hesitate to give me a call at 404/562-
8824.
(?0 -x/fJ61
ezelle S. Bennett
Remedial Project Manager
cc: Dave Mattison, NC DENR
Todd Hagemeyer, HSI GeoTrans
Lynn France, COM
Tom Augspurger, US F&W
Scott Huling, EPA ORD
Internet Address (URL) • http://www.epa.gov
Recycled/Recyclable • Printed with Vege1able Oil Based lnKs on Recycled Paper (Minimum 30% Pos1r::ons11rnen
• •
Final Remedial Design Comments
March 2000 Document
GENERAL COMMENTS
1. Many previous review comments have been addressed, and the Final Remedial
Design and Remedial Action Work Plan for Groundwater has been improved.
However, there are still some areas of disagreement, some comments that have
not been addressed, and some issues that will need careful attention and
monitoring as the Remedial Action is implemented. These are covered in the
following General and Specific Comments. If these areas of concern are
addressed, there does not appear to be any reason to delay implementation of
the Remedial Action.
2. In numerous instances, the Response stated that a specific change had been
made in the text; however, an examination of the text indicated that no change
had been made. This made verification of the desired changes very frustrating
and decreased confidence in the content of the reviewed documents. It is
recommended that the authors be much more careful in the future in all aspects
of report preparation.
3. This final design document is in much better shape than the pre-final design
document. However, there are still some significant concerns that have not
been addressed adequately. There are also a few inconsistencies in the
document which still need to be corrected for the sake of clarity. These
concerns and inconsistencies are discussed below. Additional comments on
new material are also provided below.
4. The treatment or lack of treatment of metals is one major point of contention.
The position of HSI GeoTrans and GE Lighting Systems appears to be that no
treatment of extracted ground water for metals is necessary because the P01W
does not require it or does not have standards for certain metals. However,
there are also ROD-Specified Remediation Goals, which appears to mean that
the ground water must be remediated to below those goals. It is not clear if
these goals apply to ground water only while it is in the ground or also to water
that has been extracted. This point of contention must be reconciled.
5. Monitoring of head in the wetlands is critical. The MODFLOW modeling results
are interesting and appear to indicate that there will be no adverse drawdown in
the various wetlands. However, as with all computer models, there are
numerous assumptions. The modeling results should be used as a guide rather
than being assumed to be completely accurate. It is recommended that careful
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attention be paid to monitoring the ground water levels throughout the site and
adjoining areas, especially in the wetlands, as the ground water pumping occurs.
The Ecological Evaluation of the Potential Effects of Remedial Groundwater
Extraction on Wetlands and Streams at the General Electric/Shepherd Farm
Supertund Site, prepared for HSI GeoTrans, Inc., represents a good step
towards such actions. This new report is the best discussion yet of the wetlands,
potential effects of pumping, and monitoring ne.eds. Recommendations
presented in this report should be followed.
SPECIFIC COMMENTS
6. Comment 3. The response indicates that additional QA/QC was performed to
minimize inconsistencies. This additional QA/QC was apparently very faulty, as
evidenced throughout this Response. The response to numerous comments is
that the text has been revised as suggested; however, the claimed change does
not appear in the text. It is recommended that the very basic QA/QC of verifying
the changes that are claimed should be followed. The person who writes the
response should read the text of the document.
7. Comment 9 -Instead of having only one recovery well located in the "hot zone"
pumping at half the rate as the other recovery wells, the PRPs now have no
recovery wells in the hot zone area and the only upgradient well is pumping at
40% of the rate of the other recovery wells. Thus, the majority of the
contaminant mass must travel a longer distance before it is removed. Although
the PRPs have increased the amount of contaminant mass contained from 85%
to 96% with this new design, the removal is less efficient. A much greater
portion of the contaminant mass in the "hot zone" needs to be captured sooner,
and to achieve this objective, a series of vertical recovery wells (or one
horizontal recovery well) needs to be located in the hot zone down the centerline
of the plume. In addition, due to the limited drawdown available in the saprolite
in this area., the design of the vertical wells (if used instead of a horizontal
extraction well) needs to be revised to allow for more flow from the well. Instead
of placing the pump 10 feet above the bottom of the well, the recovery well
should be constructed with a 5-foot sump (5 feet into the bedrock) at the bottom
of the well for placement of the pump. By lowering the pump, additional
drawdown is available so that the flow may be increased.
8. Comment 12. The response indicates that all treated ground water will be used
as process water and then discharged to the POTW. However, this ignores the
treated ground water stored in the storage tank that is discharged directly to the
POTW during times of plant shutdown (as shown on the Water Flow Diagram of·
Appendix G). Thus, it cannot be said that al/treated ground water will be used
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as process water. In addition, if the POTW standard for metals content in water
is less stringent than the remedial goals for the ground water, the currently
proposed system appears to be merely a way to bypass more stringent ground
water remedial goals.
9. Comment 17. All the changes do not appear to have been made, even though
the response says they were.
10. Comment 22. The text was not revised as claimed in the response.
11. Comment 39. The recommendation was not followed to add a statement
regarding manganese being found in on-site wells at an order of magnitude
greater than the remediation goal.
12. Comment 40. The text was not revised as claimed in the response.
13. Comment 41. Instead of including a brief explanation of how the bedrock
thicknesses were determined, the text merely changed the wording from "was
calculated as' to "was assigned'. This is a meaningless change. An explanation
of why these thicknesses were "assigned" is needed.
14. Comment 47. The requested explanation was not added to the text, although
Drawing 5 was changed (in addition, it is not clear where Drawing 5 is).
15. Comment 51. The cause of the mixing and homogenization was briefly
discussed; however, the implications of the non-decreasing concentrations in
MW-12A and MW-128 were not discussed. Do these concentrations in MW-12A
and MW-128 mean that there is significant contamination in the bedrock, the
saprolite, or both? What effect does this have on the remedial plans?
16. Comment 54. Table 3-5 does not include a note that SWW9 is not used for
drinking water, although the response says it does. In addition, the note should
indicate that SWW10 is not used for drinking water purposes as well.
17. Comment 55. The text was not revised as claimed in the response.
18. Comment 56. The detection of PCBs in sediment samples was not included in
the text, as requested, nor was an evaluation of the significance of detections of
organic compounds.
19. Comment 60. The text was not revised as claimed in the response.
20. Comment 62. The text was not revised as claimed in the response .
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• •
21. Comment 64. To address the concern about a gap between RW-10 and RW-
11, it appears that RW-11 was moved northward, but RW-1 O was also moved
northward, but to a greater degree. There now appears to be an even greater
gap between RW-10 and RW-11.
22. Comment 65. It is unclear if the discussion with the POTW regarding
acceptance of the ,treated ground water included the fact that the ground water
would not be treated for metals.
23. Comment 67. Table 4-1 indicates that the ROD-Specified Remediation Goals
for manganese and lead are exceeded by the design influent concentration.
Further, these metals will not be treated before being released to the POTW.
Regardless of whether or not the POTW cares about the concentrations of
these, this proposal appears to be merely a way to ignore the ROD-Specified
Remediation Goals. Apparently these Remediation Goals are meaningless once
the ground water is extracted. This issue must be resolved.
24. Comment 68. The response to this comment should actually refer back to the
response for comment 7, instead of 6.
25. Comment 82. The suggested change does not appear to have been made as
claimed in the response.
26. Comment 83 -The response is non-responsive. The proposed layout for the
pipeline was not revised and there is no discussion as to how the dangers from
construction and pipeline rupture to the bunched arrowhead habitat are
minimized with this layout. Again, the proposed layout for the pipeline conveying
effluent from the Shepherd Farm subsite to the GE subsite comes very close
(i.e., within 30 feet) to the bunched arrowhead habitat. Is not construction so
close to this endangered species habitat a risky venture with respect to harming
the plant community? In addition, could not rupture of the pipeline in this area
lead to contaminated water being discharged to this habitat? Why not play it
safe and move the pipeline further away from this habitat? Thirty feet does not
leave much room for mitigation if a problem should occur. If GE is persistent in
wanting to locate this pipeline in close proximity to the endangered habitat, it is
recommended that dual cased piping and a leak detection system be used.
27. Comment 84 -Please explain how a regular visual inspection along the pipeline
route will detect a leak if the pipeline is underground. In addition, regularly
visually inspecting the pipeline route is not included in the operation and
maintenance plan. This plan should be revised accordingly.
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28. Comment 86 -Please elaborate on what is meant by "discussions are
ongoing". At what stage are the discussions? Has access at least been verbally
agreed upon? These agreements are critical to the success of this design.
Without these agreements, major design revisions will be required. In addition,
obtaining access agreements for railroad crossings or working within railroad
easements is often a long process, and a significant delay in starting the
remedial action co.uld occur if the PRPs have only recently initiated the process.
29. Comment 92 -The new sampling location (Stream 4) proposed to monitor
surface water/sediment during the remedial action does not meet the objective
stated in EPA's comment. The station should be located immediately
downgradient of the area where the Shepherd Farm plume discharges into Bat
Fork Creek to see if this discharge may be impacting the ecosystem in Bat Fork
Creek. The proposed location is over 1500 feet downstream of the plume
discharge. At this distance, any stream contamination would likely be
susceptible to the effects of dilution and volatilization prior to reaching the
sampling point.
In addition, adding the proposed surface water/sediment sample location to
Figure 2-13 as the PRPs have done has made the document less clear. Section
2.7 refers to three historical sampling locations "as shown in Figure 2-13", but
Figure 2-13 now has four sampling locations. Either the text or the figure (or
both) needs to be revised to indicate which sampling locations Section 2.7 is
referring to.
30. Comment 89. The change was not made as claimed in the response.
31. Comment 96. The method a software program uses to make tables of
schedules does not affect a requirement that report submittals are due in 30
calendar days. The use of an old-fashioned paper calendar is recommended if
that is what it takes to understand the concept of 30 calendar days.
32. Comment 97. Table 1-1 was not revised as claimed in the response.
33. Comment 104. The statement is made that " ... any treatment goals beyond the
GE Facility and POTW requirements are arbitrary". The relationship of the GE
Facility and POTW requirements to the ROD-Specified Remediation Goals for
ground water must be clarified in order to address this statement and this issue,
and to determine what goals are to be followed.
34. Comments 105 and 106. Manganese has a ROD-Specified Remediation Goal.
See comment 104 regarding clarification of what goals are applicable.
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35. Comment 108. Collection of ground water samples from the recovery wells was
not added to Table 4-3.
36. Comment 109. Well MW-2 was not added to Table 4-3.
37. Comment 129. Well SWW-9 was not added to the text.
38. Comment 131. Table 4-3 of the Design Report indicates that hydraulic head
measurements will be made in all monitor and recovery wells on a weekly, then
monthly to quarterly basis. It appears that these data will be provided in the
quarterly and annual monitoring reports specified in the Remedial Goal
Verification Plan. These data are important and must be presented in some
form.
39. Comment 134. Table 4-3 indicates that MW-12B is a performance monitoring
well, yet this is not listed in Appendix A or in the response to the comment.
40. Comment 138. The use of the Drain Package in MODFLOW does not allow for
recharge of the ground water from a wetlands. While it is true that the wetlands
are a discharge area in the initial situation at the site, if the ground water level
falls below the wetlands, the wetlands could recharge ground water (perhaps
"drying up" in the process). A conceptual model of the physical conditions has
not been presented in the modeling report, so what is actually happening cannot
be verified. For example, it is unclear if the wetlands have a subsurface or
surface hydraulic connection with Bat Fork Creek and if the Creek is supplying
water to the wetlands. In that case, it is conceivable that the wetlands could be
a recharge area if the water table drops enough. Use of the River Package
could address that case. The use of the Drain Package based on the
recommendation for wetlands that is found in Applied Groundwater Modeling
(Anderson and Woessner, 1992) has to be reexamined in light of the more
complex physical situation at the site, in which the wetlands are immediately
adjacent to the creek, and where there are pumping wells very close to the
wetlands. Those situations are not addressed in Applied Groundwater
Modeling. It is recommended that the modeling report completely discuss the
physical situation to verify that the model scenario actually represents physical
reality. A better understanding by the modeler of the physical situation, or a
better description of it in the text, would increase confidence in the results of the
model.
41. Comment 144. It is now stated that there will be a 51% reduction in flow to the
bunched arrowhead wetlands and to the wetlands just west of Bat Fork Creek,
with no significant effect on head in these wetlands. Variations in saturated
thickness and hydraulic conductivity do affect or cause variations in drawdown,
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but many assumptions have been made in the model about assigning values to
saturated thickness and hydraulic conductivity. The head and conditions in the
wetlands will need to be monitored to verify the predictions of the model, since
reducing the flow into the wetlands by half could have negative effects. The
Ecological Evaluation of the Potential Effects of Remedial Groundwater
Extraction on Wetlands and Streams at the General Electric/Shepherd Farm
Superfund Site indicates that the proposed rate of ground water extraction
(causing a 51 % reduction in flow to the bunched arrowhead wetlands) "may
cause irreparable harm to the population of bunched arrowhead' (p. 14 of that
report).
42. Comment 147. The response indicates that in the future, simulation results may
be compared to monitoring data to improve the understanding of the
hydrogeologic system. This is strongly encouraged; periodic monitoring reports
should include comparison of observations to what has been predicted by the
modeling. Any discrepancies will need to be explained.
43. Comment 161 -We recommend that sampling of the five composite sampling
ports shown in the design drawings be retained as part of the performance
monitoring network and be sampled at the same frequency as the performance
monitor wells. This is especially important considering that no influent sampling
is to be conducted during the remedial action. Not only can the composite port
sampling provide information on the average concentrations recovered from
large portions of the plume, they can provide estimates of contaminant mass
removal from these regions. This information can then be used to better assess
how well remediation is progressing in these particular regions and whether
revisions to the recovery well pumping scheme may be advantageous. Sampling
from just the performance monitor wells will not provide this information as-the
performance well network only provides representative data, not comprehensive
data, for the site. In addition, without any influent sampling or composite port
sampling, we will have no data indicating the characteristics of the water going
into the treatment plant.
Given this composite port sampling, we also recommend that SWW9 (or a new
monitor well located in its place) replace RWSF1 in the performance well
network, especially considering the proposed location of RWSF1. First, a
performance monitor well is needed in the "hot zone" of the Shepherd Farm
plume and SWW9 is the "hottest" well. Second, with the water from RWSF1
being included in a composite sampling port sample, sampling of the this well
individually is no longer needed.
44. Comment 180 -As commented previously, contaminants will not be eliminated
from the RTC list for any performance monitoring well until it is shown that the
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contaminant is below its corresponding ROD remediation goal throughout the·
whole subsite. Because groundwater contaminants will be continuously moving
toward the recovery wells, it is quite possible that a particular contaminant may
not show up in a particular performance monitor well for a year or more.
Likewise, it is possible that a particular contaminant may disappear from a
monitor well for a year or more and then reappear later. As long as a
contaminant is a concern at a subsite, all the performance monitor wells should
be monitored for this contaminant. It should also be noted that to show that a
contaminant is below its corresponding ROD remediation goal throughout a
whole subsite, extensively monitoring beyond just the performance monitor wells
will be needed.
45. Comment 182 -Contrary to the response, the RSVP still does not discuss, nor
does it provide a schedule for, water level measurements and recovery well flow
measurements. This plan should be revised accordingly.
46. Comment 192 -Report still states 90 days instead of 60 as the response
indicates.
47. Comment 195. Attachment 1 (Sampling and Analysis Plan) to the Remedial
Goal Verification Plan does contain a Table 1-5 and a Table 3-1. The revisions
still need to be made.
48. Comment 205 -The text was not revised as claimed in the response.
49. Comment 206 -The text was not revised as claimed in the response.
50. Comments 217 to 219. No response is given for these comments.
51. Comment 263 -The replacement sentence is an incomplete sentence. Please
revise.
SPECIFIC COMMENTS -Main Report
52. pg. 3-5, Section 3.2.4.2 Groundwater -Contrary to what the text states, voes
were detected in two of the ten residential wells sampled (SWW9 and SWW10)
in 1998 and 1999. Please revise accordingly.
53. pg. 4-1, Section 4.1 Groundwater Extraction -The extraction rate proposed is
60 gpm, not 65 gpm as indicated in this section. Please revise.
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54. pg. 5-1, Section 5.1 Groundwater Extraction and Treatment at the Shepherd
Farm Subsite -Contrary to what the text states, the PCE concentration is not
currently <100 ppb. The most recent sampling (September 1999) at SWW9
indicated a PCE concentration of 112 ppb. Please revise accordingly.
55. pg. 5-1, Section 5.1.1 Recovery System -Contrary to what the text states, the
recovery wells at the Shepherd Farm Subsite will not be similar to the GE
Subsite recovery wells. The GE Subsite wells will be screened 20 feet into
bedrock whereas the Shepherd Farm Subsite wells will only be screened to the
bottom of the saprolite. This is an important distinction which needs to be better
presented, especially in the design specifications and drawings. In addition, it is
recommended that the recovery wells at the Shepherd Farm Subsite be
constructed with a sump so that the pump may be placed lower in the well as
discussed previously.
56. pg. 6-1, Section 6 Schedule And Estimated Cost -Tables 6-1, 6-2, and 6-3 are
absent from the document. Please revise accordingly.
57. Table 4-1 -The ROD remediation goals for PCE and chloroform are missing
from this table. Please revise accordingly.
58. Table 4-3 -In addition, to be complete, a reference to Appendix F should be
provided in this table to indicate all the other performance monitoring activities to
be conducted (i.e., biological monitoring activities).
SPECIFIC COMMENTS • RA Work Plan
59. pg. 2-1, Section 2.1.1 Nature and Extent of Contamination -The reference to
Table 2-4 should reference Table 2-1. Please revise.
60. pg. 2-2, Section 2.1.2 Nature and Extent of Contamination -There are two
Tables 2-2 in this work plan. The second one is from the Pre-Final RA Work
Plan and should be removed. In addition, according to the design report, the
dissolved PCE mass was estimated to be 2.2 pounds, not 6.5 pounds. Please
revise.
SPECIFIC COMMENTS -Appendix E: Numerical Groundwater Model Report
61. There are remaining concerns with the Numerical Groundwater Flow Model
MODFLOW regarding: (1) use of the Drain package for the wetlands; (2) use
and placement of the No-flow boundaries, which results in the model domain
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being a "bathtub" (i.e., the "bathtub" means that there is no flow in or out the
model boundaries: the only inflow is from recharge and the river, and the only
outflow is to the river, drains, and wells. This is often not the case when
boundaries are assumed to mimic surface topography); (3) the thoroughness of
the sensitivity analysis (especially with respect to the high conductivity values
assumed for the wetlands region); (4) whether enough head values were
determined throughout most of the model domain for calibration; and (5) the high
conductivity values used in much of the river and wetland areas. In any case,
the model results should be verified by sufficient monitoring of head throughout
critical areas such as the Bunched Arrowhead wetlands and the wetlands
immediately to the west of Bat Fork Creek.
62. pg. 6-2, Section 6 Conclusions -Please delete the last two sentences in this
section. Monitoring should continue until the most extreme conditions possible
have been encountered, and the habitat still was able to survive without any
mitigation.
63. Section 4. PROPOSED REMEDIAL DESIGN (Second paragraph, third
sentence).· The sentence should read " ... eight additionally proposed extraction
wells."
64. Figure 3-3. The title of Figure 3-3 is given as simulated head in saprolite (model
layer 2). The title should refer to the shallow bedrock instead of the saprolite.
SPECIFIC COMMENTS -Appendix F: Remediation Goal Verification Plan
65. pg. 2-1, Section 2.1 Performance Monitoring Network -Figure 2-3 shows four
surface water/sediment sampling locations and needs to be revised to indicate
the three stations to be included in the performance monitoring network. ·
66. pg. 2-3, Section 2.1.2 Surface Water and Sediment Monitoring Stations -The
last sentence of this section is confusing. Please explain what is meant by the
statement that the surface water and sediment stations "are mainly targeted for
contingent sampling of surface water and sediment". It is our understanding that
monitoring at these stations is to be on a regular schedule. What contingency?
67. pg. 2-7; Section 2.4.1 Performance Monitoring; Table 2-4 -The treated effluent
water will be analyzed for the RTCs to ensure performance of the treatment
system and reported to the Agencies. The POTW required monitoring does not
need to be reported.
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68. pg. 3-1, Section 3.1 Quarterly Monitoring Reports -How is TVOC mass
removed going to be estimated if no influent sampling is conducted? Add
influent sampling to Table 2-3 and associated text.
69. pg. 3-1, Section 3.2 Annual Monitoring Reports -Delete the bullet referring to
recovery well operation status.
70. This report contains many good recommendations for monitoring the hydrologic
conditions in the various wetlands. It is recommended that these monitoring
efforts be implemented (it is good that they do appear to have been added to the
Remedial Goal Verification Plan Sampling and Analysis Plan, i.e., Attachment 1).
SPECIFIC COMMENTS -Appendix F Attachment 1 : Remediation Goal Verification
Field Sampling and Analysis Plan
71. pg. 3-3, Section 3.2.1 Monitoring Schedule -Monitoring of hydrological
parameters is to be conducted semi-monthly as indicated in Table 3-2, not bi-
monthly as the text states. Please revise.
72. pg. 3-3, Section 3.2.1 Monitoring Schedule -Does GE have a basis of
comparison for Figure 3-1? Will future monitoring be compared to the initial
baseline to be conducted following RA start-up?
73. pg. 3-3, Section 3.2.2 Hydrology -This section and all subsequent sections
referring to activities to be included in the ecological monitoring plan need to be
revised to be more definitive with respect to the proposed monitoring plan. For
instance, all statements indicating things that "should" be conducted should be
revised to indicate that they "will" be conducted. In addition, the number and
locations of all piezometers and staff gages should be specified.
74. pg. 3-12, Section 3.2.7.5 Creek-It appears that the only location at which flow
will be monitored is the weir location. This weir is located south of the Large
Settlement Pond (which provides recharge to groundwater) and likely will show
very little impact from the groundwater recovery system. We recommend that
two additional stations be established for flow monitoring. One station should be
located near the middle of the large wetland located east of Bat Fork Creek to
monitor the reduction in flow in the area most sensitive to a reduction in
groundwater recharge. The other station should be located just downstream of
the GE subsite, where the Stream 2 surface water/sediment sampling is
conducted, to monitor the total reduction in flow to Bat Fork Creek created by the
recovery well system.
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SPECIFIC COMMENTS -Appendix F Attachment 2: Ecological Evaluation of the
Potential Effects of ... Streams
75. This-evaluation appears to be a critique of Dr. Newberry's latest study. On page
14 and throughout the remainder of the report, the evaluation indicates that the
proposed rate of groundwater extraction may cause irreparable harm to the
population of bunched arrowhead. If the groundwater design was based, in part,
on this study, then· why is the 77 gpm pumping rate still being proposed?
SPECIFIC COMMENTS -Appendix G: Design Calculations
76. Effluent Transfer Pump Design Calculations -For the sake of consistency and
clarity, these calculations should be revised using the actual design flow
(presently 77 gpm), not 82.5 gpm.
77. The supporting information for the design (calculations, vendor info, etc.)
supports the selection of the equipment specified. Comments on the discharge
were related to how the potential RO system would be implemented (triggers,
design criteria, etc.) and how the storage tanks would be used in the discharge
scenario. To address these concerns a significant change has been made in
that the system will now have no direct surface water discharge. A flow diagram
provided in Appendix G shows that water from the treatment system will be
directed to the existing storage tanks. From the storage tanks the water would
either be used for processing or discharged to the POTW. Actually this is a
much better option than before because it will be more reliable in the long-term.
Below are some comments related to this plan:
a) Since the remediation system will not have a surface water discharge,
one could assume that an NPDES permit is no longer needed. In the
permitting requirements section of the report an NPDES permit is not
identified, however, hasn't GE been discharging under an NPDES permit
and don't they still have one in place. Please confirm the status of the
permit, if one exists, and if so, does GE plan on keeping it. If GE plans on
keeping it, why?
b) Drawing number 5 (and others) continue to show a surface water outfall.
Drawing 5 shows a locked valve which would prevent discharge to the
outfall, directing the flow to the tanks. EPA may consider that an option
would be to put in a blind flange instead of the valve, making it very
difficult to discharge to the outfall.
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•
c) In response number 4 it states the storage tanks are 30,000 gallons each
and gives the tank dimensions as 12 feet in diameter and 5 feet high.
These dimensions would result in a 4,227 gallon tank. The dimensions
appear to be incorrect because the drawings, and other references show
two 30,000 gallon tanks. It is not critical that we know the exact
dimensions, but it is important to understand if the tanks are 4,200 or
30,000 gallon capacity. If the tanks have a 4200 gallon capacity, this
could result in problems managing the flow rates from the treatment
system, depending on the tank piping sizes and configurations.
d) The tanks have not been sized using any design criteria related to the
treatment system. They are existing tanks that are being put into service
for this purpose. As long as the 30,000 gallon capacity is correct, they
would be sufficient.
SPECIFIC COMMENTS· Appendix H: Hydrologic Study of the Bunched
Arrowhead Habitat
78. Please correct the table of contents.
Fish and Wildlife Service Comments:
Despite Service and USEPA efforts to convey the importance of the remedial
objective of avoiding impacts to habitat supporting the federally listed
endangered bunched arrowhead, Sagittaria fasciculata, the documents and
appendices fail to present a design to meet this objective. In fact, the proposed
design is predicted to impact the head and flow to wetlands supporting this
endangered plant; this is not acceptable.
Along with extracting/treating contaminated groundwater (a remedial objective
the Service has previously endorsed), the overall remedy includes an objective,
as stated on page 1-5 of the May 1999 60% Design Report, of " ... avoidance of
adverse impacts to wetlands, including a wetland containing the Federally-
endangered plant species known as the bunched arrowhead." While much work
on the bunched arrowhead has been incorporated, the explicit objective of
protecting the bunched arrowhead does not appear in the current document's
listing of remedial objectives /absent from page 1-5 and 1-6\: it should be added
and re-emphasized.
Despite the absence of the stated objective, the project consultants have clearly
done groundwater monitoring, groundwater modeling, a hydrologic assessment
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• •
of the bunched arrowhead habitat and proposed a bunched arrowhead habitat
monitoring plan in an attempt to work toward this goal. While the model
development appears sound, its applications are incomplete. The model
predicts impacts to wetlands upon startup, and predicts that steady state impacts
will not be known for three years. This information should have led to a redesign
of the proposed extraction system. We suggest three significant modifications of
model application. First, the model should be run with a condition of zero
predicted drawdown rather than 0.5 feet: it should also seek to minimize any
reductions in flow. By definition, the 0.5 feet drawdown is a level considered to
put the species at risk, which is what we are striving to avoid. Model scenarios
for zero predicted drawdown are a necessary part of remedial action planning for
this site. Second, the model should be run to predict ultimate drawdown through
longer modeling runs (i.e., if modeling indicates three years to steady state, then
run the model out three years to predict the full impacts. Third, and most
significantly. the model should be used to fit various potential extraction designs
to model runs that predict no impact to wetlands, either through lower pumping :
rates. seasonally-variable pumping rates. or alternate extraction well locations.
There are myriad extraction designs that could be developed and tested; the
model projections indicate a need to revisit other designs.
With the inherent uncertainties in models and the limited model fitting to varying
stress periods in this case, the proposed biological monitoring of the habitat is ·
an appropriate safeguard. It should not, however, replace a design that is
envisioned to be protective from the outset.
We previously forwarded a US Geological Survey recommendation for use of
telemetered wells to facilitate verification monitoring. We believe the
telemetered wells would help with monitoring as well as an adaptive extraction
schedule, whereby withdrawals for treatment were directed by a robust
understanding of the near-real-time water budget. This approach should be re-
evaluated.·
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• •
April 10, 2000
Ms. Giezelle Bennett, Remedial Project Manager
Waste Management Division
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Street, S.W.
Atlanta, Georgia 30303-3104
Dear Ms. Bennett:
The U.S. Fish and Wildlife Service (Service) has reviewed the
March 2000 "Final" Remedial Design and Remedial Action Work Plan
for Groundwater for the General Electric/ Shepherd Farm
Superfund Site, East Flat Rock, Henderson County, North Carolina.
Service comments are provided in response to your March 15th
request and pursuant to the Fish and Wildlife Coordination Act,
as amended (16 U.S.C. 661-667e), and provisions of Section 7 of
the Endangered Species Act of 1973, as amended (16 U.S.C. 1531-
1543). These comments are intended as technical assistance for
the U.S. Environmental Protection Agency's (USEPA) assessments and
planning conducted pursuant to the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980, as amended (42
U.S.C. 9601 et seq.); they do not represent any position that the
U.S. Department of the Interior may adopt concerning possible
injury to natural resources under their trusteeship.
Despite Service and USEPA efforts to convey the importance of the
remedial objective of avoiding impacts to habitat supporting the
federally-listed endangered bunched arrowhead, Sagittaria
fasciculata, the documents and appendices fail to present a
design to meet this objective. In fact, the proposed design is
predicted to impact the head and flow to wetlands supporting this
endangered plant; this is not acceptable.
Along with extracting/ treating contaminated groundwater (a
remedial objective the Service has previously endorsed), the
overall remedy includes an objective, as stated on page 1-5 of
the May 1999 60% Design Report, of" ... avoidance of adverse
impacts to wetlands, including a wetland containing the
Federally-endangered plant species known as the bunched
arrowhead." While much work on the bunched arrowhead has been
• •
incorporated, the explicit objective of protecting the bunched
arrowhead does not appear in the current dacllment~s Ji sting: of
remedial objectives {absent from page 1-s and 1-6) · it shouJ d be
added and re-emphasized.
Despite the absence of the stated objective, the project
consultants have clearly done groundwater monitoring, groundwater
modeling, a hydrologic assessment of the bunched arrowhead
habitat and proposed a bunched arrowhead habitat monitoring plan
in an attempt to work toward this goal. While the model
development appears sm1nd. its applications are incomplete. The
model predicts impacts to wetlands upon startup, and predicts
that steady state impacts will not be known for three years.
This information should have led to a re-design of the proposed
extraction system. We suggest three significant modifications of
model application. First the model shouJ d be nm with a
condition of zero predicted drawdown rather than o 5-feet· it
sbo11ld also seek ta minimize any redllctions in flow. By
definition, the 0.5-feet drawdown is a level considered to put
the species at risk, which is what we are striving to avoid.
Model scenarios for zero predicted drawdown are a necessary part
of remedial action planning for this site. Second the model
should be run to predict ultimate drawdown through longer
modeling runs (i.e., if modeling indicates three years to steady
state, then run the model out three years to predict the full
impacts. Third and most significantly the model should be used
to fit various potential extraction designs to model nms that
predict no impact to wetlands either through lower pumping
rates seasonally-variable pnmping: rates or alternate extraction
well locations. There are myriad extraction designs that could be
developed and tested; the model projections indicate a need to
revisit other designs.
With the inherit uncertainties in models and the limited model
fitting to varying stress periods in this case, the proposed
biological monitoring of the habitat is an appropriate safeguard.
It should not, however, replace a design that is envisioned to
be protective from the outset.
We previously forwarded a U.S. Geological Survey recommendation
for use of telemetered wells to facilitate verification
monitoring. We believe the telemetered wells would help with
monitoring: as well as an adaptive extraction scbed1lle whereby
withdrawals for treatment were directed by a robust ,mderstandi ng
of the near-real-time water budget This approach should be re-
evaluated.
We will call you in the near future to discuss these significant
issues. While the Service has numerous technical comments on the
documents (particularly those related to the bunched arrowhead
studies and proposed habitat monitoring), they do not appear to
merit detailed discussion until these larger issues on model
• •
application and proposed remedial design are adequately
addressed.
Thank you for the opportunity to comment on the documents. If
you have any questions regarding this letter, please contact me
at [e-mail] or 919/856-4520 (ext. 21).
CC:
Sincerely,
Tom Augspurger
Ecologist
Dr. Garland Pardue -FWS, Raleigh, NC
Mr. Jim Lee, REO, DOI/OEPC, Atlanta, GA
Dr. Allen Robison, FWS, AES/TS-EC, Atlanta, GA
Dr. Diane Beeman, FWS, AES/TS-EC, Atlanta, GA
Mr. Mark Cantrell, FWS, Asheville, NC
Mr. Lynn Wellman, USEPA/ETAG, Atlanta, GA
NCDSWM-Superfund Section, Raleigh, NC
c:\wp6.1\ge400.esa
• •
UNITED STATES ENVIRONMENT AL PROTECTION AGENCY
4WD-NSMB
Ms. Janet Boyer
EHS Manager
GE Lighting Systems, Inc
3010 Spartanburg Highway
Hendersonville, NC 28792
REGION4 £.CE.\\JE.0
61 Forsyth Street ~ . 9 .Atlanta, Georgia 30303-3104 f\:.'3 CZ. CZ. ,99
osf:.ci\O~
February 16, 1999 s\J?~?,'r\J~ •
SUBJ: GE/Shepherd Farm NPL Site
East Flat Rock, NC
Dear Ms. Boyer:
Enclosed are the Agency's comments on the Final (100%) Remedial Design and
Remedial Acti0on Work Plan for Soil at the GE Subsite dated November 13, 1998.
Replacement pages will be acceptable. However, PLEASE review the replacement pages
before submittal to ensure that all comments have been incorporated. The replacement
pages should be submitted to the Agency no later than March 9, 1999.
If you have any questions, please do not hesitate to give me a call at 404/562-8824.
cc: David Mattison, NC DENR
ezelle S. Bennett
Remedial Project Manager
Todd Hagemeyer, HSI GeoTrans
Lynn France, COM
• •
REMEDIAL ACTION WORK PLAN FOR SOILS AT GE SUBSITE
List of Figures
1. The response to US EPA comment #6 stated that the List of Figures and the title
of Figure a: 1 have been revised. However, the List of Figures in the revised
document does not include this correction. Please correct this oversight. ·
Section 2.4.4 Spot Excavation
2. The response to US EPA comment #1 states that the cap design has been modifi.ed
to address the two areas of polychlorinated biphenyl (PCB) contamination that lie
to the west of the dry sludge impoundment (OSI). However, Section 2.4.4 has not
been modified. Please revise the first two sentences of Section 2.4.4 to state that
"The cap to be installed at the OSI covers the entire unit with the exception of a
small area in the northwest corner and two areas along the western perimeter of the
fence and adjacent to Landfill A. These areas will be reinediated by excavation."
Furthermore, please revise the fourth sentence of this section to include the
appropriate estimate of soil to be removed, based upon the excavation of these
three areas.
Section 3.1.2 Confirmation Sampling
3. The response to US EPA comment is adequate but still does not address any
contingencies if volatile organic compound (VOC) contamination exceeds North
Carolina soil remediation standards. Please include the following statements at the
end of the third paragraph in Section 3.1.2:
"In the event that soil analytical results exceed North Carolina soil
remediation standards, HSIG shall determine the extent of voe
contamination. If the extent of VOC contamination appears to be limited
(i.e., <1 O cubic yards), HSIG shall remove the VOC contaminated soils and
place in the OSI and notify all parties of this action. If the extent of VOC
contamination appears to be excessive, HSIG shall consult with GE, the US
EPA and the NC OENR to determine the appropriate course of action."
4. The response to US EPA comment #20 states that a 10.2 electronvolt (eV) lamp
has been determined to be an appropriate lamp based on the ionization potential
of the VOCs present at the site. However, Section 7.3.1 of the Construction Health
and Safety/Contingency Plan (Attachment 3) states that a photoionization detector
(PIO) equipped with a 11.7 eV lamp shall be used. Please clarify this discrepancy
and make the appropriate revisions.
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• •
5. The bullet list in the fourth paragraph of this section has several typographical
errors. The first sentence of the fifth bullet should state that "Two soil samples will
be collected at each confirmation sample location." The second sentence of the
seventh bullet should state that "Sample shipments to the offsite laboratory will be
transmitted as soon as practical and no later than five days after sample collection
to assure that the seven-day time limit for extraction is met." Lastly, the first
sentence of the eighth bullet should state that "If field analysis shows that the
samples has less than 10.0 ppm PCBs, the split sample will be shipped to a fixed
laboratory for PCB analysis using EPA Method 8081." Please correct these
oversights.
Figure 3.1 Decision tree for landfill excavation
6. Figure 3.1 should be revised to incorporate the text of Section 3.1.2 and the
response to US EPA comment #10. Specifically, following the action "Screen
headspace for VOCs using PIO," Figure 3.1 should include the decision, "Does PIO
indicate VOCs > 1 ppm." Figure 3.1 should indicate that a "No" outcome should
proceed to the action "Collect confirmation soil samples." However, Figure 3.1
should indicate that a "Yes" outcome results in the action "Submit soil sample to a
fixed laboratory for voe analysis." This action should further include the decision
"Do results exceed NC soil remediation standards." The~'No" outcome can proceed
directly to the action "Collect confirmation soil samples." However, the "Yes"
outcome should proceed to the decision "Is voe soil contamination < 1 O cubic
yards." The "Yes" outcome for this decision ~hould proceed to the action "Remove
voe contaminated soils" before proceeding to the action "Collect confirmation soil
samples." However, the "No" outcome should proceed to the action "Discuss
options with US EPA and NC DENR" beiore proceeding to the action "Collect
confirmation soil samples." Lastly, the "No'.' outcome for the decision, "Total PCBs
>1 0 ppm" should be placed at the bottom of the decision box rather than at the top.
Please correct these oversights.
Section 4.8.1 Sitewide Waste Management
7. The response to US EPA comment #21 states that "Washwater will not be spread·
on the landfilled soils if they are already wet from recent precipitation." Please
revise the third bullet of the second paragraph of this section, and all other
appropriate sections of the Remedial Design Work Plan, Fina! (100%) Remedial
Design and associated specifications/attachments, to include the above statement.
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• •
FINAL (100%) REMEDIAL DESIGN FOR SOIL AT THE GENERAL ELECTRIC SUBSITE
Ust of Figures
8. The title for Figure 7 .1 should be given as "Schedule for soil remedial action at GE
Subsite." Furthermore, the title for Figure 7.2 should be given as "Detailed cap
construction schedule." Please correct these oversights.
Section 1.2 Site History
9. The last paragraph of this section is incorrect. The original September 1995
Record of Decision (ROD) prescribed a multi-layer cap remedy for Landfill A,
Landfill Band the DSI. The September 1995 ROD was modified by the September
1998 Explanation of Significant Difference (ESD) to include the excavation of
Landfill A and Landfill B, the disposal of such wastes into the DSI, and the
installation of a multi-layer cap over the DSI. Please correct these oversights.
Section 1.4 Report Organization
1 o. The fifth sentence of the second paragraph of this section should be revised to
state that-"Section 6 summarizes the Operation and Maintenance (O&M) Plan,
which is included as Attachment 5." Please correct this oversight.
Section 1.5.3 Dry Sludge lmpoundment
11. The response to US EPA comment #47 states that the cap design has been
modified to address the two areas of PCB contamination that lie to the west of the
DSI. However, Section 1.5.3 has not been modified. Please revise the first two
sentences of the third paragraph of Section 1.5.3 to state that "The cap to be
installed at the DSI covers the entire unit with the exception of a small area in the
northwest corner and two areas along the western perimeter of the fence and
adjacent to Landfill A. These areas will be remediated by excavation."
Furthermore, please revise the fourth sentence of the third paragraph of this section
to include the appropriate estimate of soil to be removed, based upon the
excavation of these three areas.
Section 4.2 Disposal of Excavated Material
12. The first sentence of this section should reference Section 4.8.2 of the Remedial
Design Work Plan. Lastly, the last sentence of this section states that a
description of the disposal of spent cleaning fluids is provided "above." However,
this description was inadvertently omitted. Please correct these oversights.
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• '''"· 1' ,:.<~.:.
ii1$.·: ·-.sr: ::~r .. :,,,:• :1~r·
.• ~
: 1'
• •
13. The response to US EPA comment #73 indicates that Section 4.2 was revised to
include the disposal of organics from cleaning and grubbing operations into the
OSI. However, this information was inadvertently omitted. Please correct this
oversight.
Section 5.4 Drainage Layer
14. In accordance with the response to US EPA comment #69, please delete all
references to the Preliminary (30%) Remedial Design Report in this section.
Section 5.7.2 Slope Stability
15. The fourth sentence of this section should be revised to state that "The sideslopes
are moderately steep, however, the project drawings specify a maximum slope of
4 to 1, or 25%." Please correct this oversight. ·
Section 6 Operation and Maintenance
16. The fourth sentence of the second paragraph of this section is incomplete. Please
correct this oversight.
Section 7.2 Estimation of Project Cost
17. In accordance with Table 7.1, the last sentence of this section should state that
"The total cost estimate of $1,191,604 reflects a cost within ±15% of the anticipated
actual cost." Please correct this oversight.
ATTACHMENT 1 CONSTRUCTION SPECIFICATIONS FOR SOILS REMEDIAL
ACTION AT GE SUBSITE
Section 02776 Geosynthetic Materials
18. Please revise Paragraph 3.1.B.3(c) of this Section to state that "Geomembrane
placement shall not proceed at a sheet temperature below O degrees Celsius (32
degrees Fahrenheit) or above 50 degrees Celsius (122 degrees Fahrenheit)."
Section 03300 Cast-In-Place Concrete
19. Paragraph 2.1.F of this Section should state "Geotextile: See Section 02776, Part
2.3." Furthermore, Paragraph 3.2.H of this Section should state that "A geotextile
pipe wrap, as described in Part 2.3 of Section 02776, shall be placed around gas
vent pipes prior to placement of concrete, as shown on the plans." Please correct
these oversights.
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• •
ATTACHMENT 3 CONSTRUCTION HEALTH AND SAFETY/CONTINGENCY PLAN
20. Figure 1.1, Figure 2.1, Figure 5.1, Figure 11.1 and Figure 12.1 were inadvertently
omitted. Please correct these oversights.
Section 10.1 Introduction
21. The fifth sentence of the second paragraph of this section should state that "Only
Section 10.8 below will generally be applicable to the RA work." Please correct this
oversight.
Section 10.4 Pre-Entry Procedures
22. The second sentence of this section should state that "These steps, along with the
atmospheric requirements in Section 10.6, represent acceptable entry conditions."
Please correct this oversight.
Section 11.3.1 . Prevention
23. The seventh bullet of this section should state that ''Portable fire extinguishers will
be available throughout the RA work area as describe in Section 10.5." Please
correct this oversight.
Appendix B' Heat Stress Prevention Program
24. The page numbers for the text portion of this appendix should be in Arabic
numerals rather than Roman numerals. Please correct this oversight.
25. The titles for all of the headings in Section 2.3 should be in bold font. Please
correct this oversight.
ATTACHMENT 4 CONSTRUCTION QUALITY ASSURANCE PLAN
Section 1.3.4 Quality Assurance Team
26. The corrections to Section 1.3.4 are handwritten. Please type the corrections.
Furthermore, the third sentence of this section should state that "This individual will
be NICET Level IV certified." Please correct these oversights.
Section 4.1 Common Fill Grading
27. The response to US EPA comment #41 states that since the testing frequency and
acceptance criteria are referenced to the appropriate sections of the Specifications
-5-
• •
and the Construction Quality Assurance Plan is located in the same binder as the
Specifications, it should not be necessary to repeat this information. However, the
information provided in the first item of Section 4.1.1 and the first item of Section
4.1.2 is inconsistent with the Specifications. Please revise the two items given
above to either provide the information as provided in the Specifications or simply
reference the appropriate sections of the Specifications. Additionally, the third item
of Section 4.1.2 should state that "The grading layer will be measured to plus or
minus three inches measured across any 100-foot section." Please correct this
oversight.
Section 4.2 Structural Fill Grading
28. The response to US EPA comment #41 states that since the testing frequency and
acceptance criteria are referenced to the appropriate sections of the Specifications
and the Construction Quality Assurance Plan is located in the same binder as the
Specifications, it should not be necessary to repeat this information. However, the
information provided in the first item of Section 4.2.1 and the first item of Section
4.2.2 is inconsistent with the Specifications. Please revise the two items given
above to either provide the information as provided in the Specifications or simply
reference the appropriate sections of the Specifications. Additionally, the third item
of Section 4.2.2 should state that "The grading layer will be measured to plus or
minus two inches measured across any 100-foot section." Please correct this
oversight.
Section 4.3 Barrier Soil Layer
29. The response to US EPA comment #41 states that since the testing frequency and
acceptance criteria are referenced to the appropriate sections of the Specifications
and the Construction Quality Assurance Plan is located in the same binder as the
Specifications, it should not be necessary to repeat this information. However, the
information provided in Section 4.3.1 and Section 4.3.2 is inconsistent with the
Specifications. Please revise the two Sections to either provide the information as
provided in the Specifications or simply reference the appropriate sections of the
Specifications. Additionally, the thirteenth item of Section 4.3.2 should state that
"The final clay layer will be measured to plus or minus two inches measured across
any 100-foot section." Please correct this oversight.
Section 4.5.2 Construction
30. Please revise the first sentence of Item 8 of this section to state that
"Geomembrane placement shall not proceed at a sheet temperature below 0
degrees Celsius (32 degrees Fahrenheit) or above 50 degrees Celsius (1·22
degrees Fahrenheit)."
-6-
" :; .....
•
ATTACHMENT 6 DESIGN CALCULATIONS
Slope Stability Calculations
•
31. The first sentence of Section B of these calculations should state that "the side
slope for the fill area is proposed to be 4:1 (25%) or 14 degrees." Please correct
this oversight.
ATTACHMENT 7 PREFINAL DESIGN CONSTRUCTION DRAWINGS
32. The response to US EPA comment #85 stated that the drawing had been revised
as requested. However, the Final Design Construction Drawings do not include
drawings of necessary items such as the site layout, temporary buildings, job
trailers, decontamination facilities, etc. The design drawings must detail all
components for the excavation of the Landfill A arid Landfill Band all components
for the construction of the landfill cover, including ancillary items. Please correct
these oversights.
Drawing No. 1 Site Plan Existing Features
33. Drawing No. 1 indicates the approximate locations of four wetlands. The PreFinal
(90%) Remedial Design Report indicated that the southern tip of Landfill B lies in
a wetland. However, this submittal indicates that the wetland lies approximately 12
feet from the tip of Landfill B. Please provide justification for this delineation of the
Wetland considering that the previous correspondence has indicated that th~
wetlands had not been delineated as of yet. Please provide the details of the exact
locations of Landfill Band the wetlands. If the wetlands have not been delineated
as of yet, please clarify if the contractor is required to complete this task and
provide a schedule for implementation.
Drawing No. 3 Landfill A Excavation and On-Site Disposal Plan
34. The response to US EPA comment #47 states that the cap design has been
modified to address the two areas of PCB contamination that lie to the west of the
OSI. However, Drawing No. 3 has not been modified. Please revise Drawing No.
3 to include the excavation of the two small areas along the western perimeter of
the fence and adjacent to Landfill A.
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