3402_HanesMillRoadMSWLF_MSE_commemt_FID1401206_20200421

ROY COOPER
Governor

MICHAEL S. REGAN
Secretary

MICHAEL SCOTT
Director
Solid Waste Section

##, 2020

Ms. Jan McHargue, PE
Assistant Director
City Winston-Salem/Forsyth County Utilities
P.O. Box 2511
Winston-Salem, NC 27102

Re: Comments on Permit Amendment Application Mechanically Stabilized Earthen Wall
Construction and Landfill Expansion
Hanes Mill Road Municipal Solid Waste Landfill
Forsyth County, North Carolina
Permit No.3402-MSWLF-1997, File Identification No. (FID) XXX

Dear Ms. McHargue:

The Division of Waste Management (DWM), Solid Waste Section (the SWS) completes a
review of the following documents:
• Permit Amendment Application (Permit Application), Hanes Mill Road Landfill,
Winston-Salem/Forsyth County Utilities, Winston-Salem, North Carolina. Prepared by
HDR Engineering, Inc. of North Carolinas, Charlotte, NC (HDR). Dated December 31,
2019. (FID1386718).

Based on the reviews, the SWS has comments on the Permit Application which are stated below.

A-Facility Plan
1. (Section 1.2) Provide the following info to this Section.
i. According to the permit dated July 25, 2017 (DIN 27884) and approved permit
application (DIN 28143), the active lined MSWLF (a.k.a LEU) has an approved
waste footprint of 90 acres, not 88 acres. If the County/City Utility (CCU)
proposes to reduce the waste footprint to 88-acres as stated in this section, please
describe the discrepancies of landfill waste footprint (is the as-built survey data
previously submitted is incorrect?). Otherwise, please provide the correct waste
footprint throughout the permit application.
ii. The Facility Plan drawings should note the subsequently added properties
described in the second paragraph of this Section.
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iii. Since the survey stations are shown on the Facility Plan drawings, please clearly
describe the proposed mechanically stabilized earthen (MSE) wall by the stations
throughout the entire permit application rather than use Phases A & B alone.
iv. The proposed MSE wall construction will increase the waste footprint from 88 to
94 acres as described in the fourth paragraph of the Section.
a. On the Facility Plan drawings use colored shade/legend/hatch and the survey
stations to show the increase areas of the waste footprint. Those figures
should be referenced in the Section.
b. On the Engineering Plan drawings, use the full size drawings (locally blow-up
sections) to show the existing grades, proposed subgrades, and base liner
grades for the cell floor and side-slope area (two different base liner system
are proposed) and the detailed connections between the proposed and existing
base liner system. These drawings will be the references of the Technical
Specifications.
v. In the fifth paragraph, the survey stations should be used for easy understanding
of the narratives and length of the wall segments. For example, the 4,125 linear
feet of the MSE wall, as shown on Drawing XX from Station 0+00 to 41+25.
Where are the south or north terminations located?

2. (Section 1.6, the last sentence of the 4th paragraph) The CCU shall notify the SWS within
24 hours of attempted disposal of any waste the landfill is not permitted to receive,
including waste from outside the area the landfill is permitted to serve according to Rule
15A NCAC 13B .1626(1)(a). Please add the requirement to this paragraph.

3. (Section 1.8.1) Provide the following info to this Section.
i. The gross capacity of the landfill, as defined in the Permit Condition No.1,
Attachment 2 of the facility permit dated July 25, 2017 (DIN 27884), is 13.7
million cubic yards (MCY). The proposed gross capacity of 16.5 MCY is 10%
more than the approved one which triggers a substantial amendment to the permit
according to NCGS 130A -294(b1)(1). The CCU shall provide sufficient and
adequate information in the permit application according to the State Law and
Rule and local government ordinance stated below to the SWS for making a
permit decision:
a. Local governmental approval according to Rule 15A NCAC 13B .1618(c)(5).
b. Amendment to the current franchise agreement (which will expire on March
6, 2030) with approval of the proposed gross capacity of 16.5 MCY, the
agreement term extended to the life-of-site permit expiration date of April 09,
2057, per NCGS 130A-294(a2).
c. The design, construction, and inspection of the long-term performance of the
structure and foundation of the proposed MSE wall may also be governed and
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regulated by the North Carolina Building Codes (specifically Chapter 17-
Special Inspections). Because the wall height exceeds from 10-feet tall, the
local governments – City of Winston-Salem and/or Forsyth County [such as
Winston-Salem/Forsyth County Inspection Division, referring Unified
Development Ordinances (UDO) – Chapter C, Article V, Section 5-7(B)] shall
also have the jurisdiction of review, inspection, and approval of the design and
construction activities of this wall project. If the City or the County decides
that the codes are not applicable for the wall project at the landfill, the CCU
should make the request of a copy of the decision letter on this matter, which
shall be appended to the Permit Application for the wall.

4. (Sections 1.8 & 1.9) Since the increased area (at least 4 acres) will be used for waste
disposal as stated in Table 1, the connections of the new and existing landfill base liner
system must be clearly described in the Permit Application. The typical details of liner
connections relative to the wall segment should be shown the drawings.

5. (Section 1.8.2) Provide the following info to this Section.
i. The maximum landfill final grade of 1,026 feet amsl shown on Drawings 00C-09
& 00C-10 is restricted by the City Winston-Salem/Forsyth County Unified
Development Ordinances (UDO). Please include the info to this Section.
ii. Define the “western termination” of the MSE wall by a survey station.
iii. Descriptions of the proposed MSE wall - Phase A, defined by survey stations
including length, height, widths of the bottom and top of the wall, exterior slope,
etc.

6. (Section 1.8.3) Provide descriptions of the proposed MSE wall- Phase B, defined by
survey stations including length, height, widths of the bottom and top of the wall, exterior
slope, etc.

7. (Section 1.8.4)
i. What is EVO site borrow area? Please provide the reference on the Facility Plan
drawing.
ii. The depiction of the approved alternate base liner system is incorrect. Should the
60-mil texture geomembrane be used as one of the components of the approved
base liner system (Ref Detail 2 of Drawing 00C-19)?
iii. The Table 2 shows the expansion area is about 3.8 acres which is not consistent to
the approximately 6-acre additional area (increasing from 88 to 94 acres)
described in Section 1 or Section 1.10.3.2. Please clarify.
iv. The off-site borrow source must have a NC mining permit; otherwise, the soil
borrow must be tested for chemical contamination. Test soil/fill material for
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chemical analyses by a NC certified laboratory to demonstrate that the soil/fill
meet the “unrestricted use standards" - meaning concentration of a contaminant, if
any, for each borrow that is acceptable for all uses per NCGS 130A-310.65.
Analytical test results must show any contaminant of concern with a
concentration less than or equal to that in the NC Industrial/Commercial Health
Base Preliminary Soil Remediation Goal (NC PSRG) which can be found in the
web link:
https://files.nc.gov/ncdeq/Waste%20Management/DWM/SF/RiskBasedRemediati
on/updates-december-2019/1.-2019-Dec-PSRG-Table.pdf. The testing program
should be included in the CQA Plan and the Specification – Section 31 23 00.
The testing results should be available for review and approval by the Engineer in
the pre-construction meeting. Please add the requirements to the related Sections
of the Plans & Technical Specification.

8. (Section 1.9.2) This Section should discuss the baseliner system in the expanded area
resulting from the wall construction as shown Drawings 00C-15, 18 & 20.

9. (Section 1.9.4) Add the reference of K – Calculation of the Permit Application to the
modification to the stormwater calculation.

10. (Section 1.10) The modification of existing LCR system should be clearly described in a
format that can be coordinated with the Technical Specification and easier reviewed by
the general public.
i. Use survey stations to describe the area of concerns and summarize the item of
concerns, quantity (number of items or linear feet) by a table such as relocation of
sump pump, pump risers & leachate line, and extensions of leachate cleanout
pipes, etc. This request can be presented in this subsection, Technical
Specification, or on figures.
ii. The extension of pump riser to the top of the MSEW will impact the pump lifting
head at each pumping station. The Engineer Plan and K – Calculations should
provide the hydraulic calculations to demonstrate that a new sump pump is not
required.
iii. Is leachate quantity expected to increase due to the increase of waste footprint to
70 acres and the conclusion made in the last paragraph of Section 1.10.2 & K –
Leachate Rate Generation based on HELP Model?
iv. The Permit Application must provide a plan which clearly describe the procedures
for protecting the landfill baseliner system and LCR piping from a fire caused by
methane released or migrated from open LCR piping.

B- Engineering Plan
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11. The Permit Application contains design and construction of the proposed MSE wall and
landfill expansion – Phase A which are prepared by HDR and Tensar Corporation.
According to Rule 15A NCAC 13b .1620(b), in the plan each design engineer shall
provide the statement of certifying the responsible portion(s) of the project and bearing
his or her seal of registration.

12. (Section 1 – Facility Design)
i. Please use survey stations to describe the subjected areas such as wall segments
for Phases A & B.
ii. This Section states that the top portion of the proposed MSE wall will be used as a
haul road. Please address the following concerns.
a. Has the road safety design been considered? The safety design (such as guard
rails, super-elevation/bank at turns, speed limits, etc.) and related drawings
should be provided in the application.
b. Will the haul road be one-way-traffic or two-way-traffic lanes? The proposed
traffic route/control of the haul road should be described and illustrated on the
drawings.
c. The stormwater/surface water on the road surface (roadside draining system)
must be properly drained away from the landfill waste footprint & LCR
system and safely conveyed to nearby drainage features. Please describe the
stormwater/surface water hydraulic design and summarize the conclusions
from K– Calculation of the Permit Application in this Section.
d. No matter what material is used to pave the road surface [a less impermeable
surface layer (such as asphalt) or an earthen material (such as gravel and
dirt)], the road should be designed and constructed a subsurface drainage layer
underlain by a layer of geosynthetic liner to safely remove and drain
percolated water from road surface into stormwater drainage network.
Otherwise, the reinforced fill of the MSE wall must be designed by
“Undrained Condition.” Please append the hydraulic design calculations, and
detailed drawings of the subsurface draining layer & the layout of the drainage
network. The material and construction specifications should be included in
the CQA Plan (Section C) and Technical Specification (Section J).
iii. Add the referenced drawing numbers to the narratives.
iv. The proposed MSE wall info concluded from designs in K-MSE Wall Calculations
should be summarized in the Engineering Plan which shall satisfy the requirements in
Rule 15A NCAC 13B .1620(d)(2).

Additionally, the proposed MSE wall will be integrated into the MSWLF. Therefore, the
following sections in the Engineering Plan should summarize conclusions from the engineering
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design calculations – K Calculations for both wall and landfill, either individually or together
continency to the designing engineers’ concerns.

13. (Section 1.1 & Specification 31 10 00)
i. Please provide the info of site clearing activities including locations and acreages.
The locations where are subject to clearing activities should be added to the
Engineering Plan drawings.
ii. Add the on-site burning (open burning) requirements.

14. (Section 1.2) This Section should discuss and summarize foundation design for the
proposed MSE wall/berm according to J- Geotechnical Data. DO NOT just refer J-
Geotechnical Data of the Permit Application. Specifically, a very soft layer in the wall
foundation is identified by the subsurface soil investigation and the potential impact on
the wall foundation design should be discussed in Section 1.2.
i. Bearing capacity of the wall/berm which will likely be subject to various loading
from waste-laden vehicles on top of the wall/berm, active earth pressure from
landfill waste loading, earthquake, etc.
ii. Settlement analysis. The settlement of foundation soil underneath the wall/berm
due to various loading. The settlement analysis should consider both total
settlement and differential settlement along the both directions - longitudinal/wall
alignments and transverse/across wall directions.
iii. Sliding analysis.
iv. Eccentricity / rotational failure analysis.
v. Foundation drainage system/underdrain. Prior to constructing the first layer of the
wall, the base grade should be regraded for facilitating surface water drain, or the
properly designed the surface/subsurface drainage network under the wall system
should be constructed. Without the above-mentioned drainage a section of wall at
low lying area will inundate by surface water for a period of time which may
result in foundation failure.
a. The Engineering Plan drawings (layout plan and details) should include
designed the surface/subsurface drainage network under the wall system.
b. The sizing of surface/subsurface drainage network including related
hydrology/hydraulic designs shall be appended in the Permit Application.

15. (Sections 1.3.2 & 1.3.3) Based on the cross-sections shown on the drawing Sheet No.
00C-15 and the narratives in Section 9.1 of the Operations Plan, the new expanded area
(MSE wall inboard slope area) will be constructed at sloped area according to the
alternative baseliner system as stated in Section 1.3.2 and as shown drawing Sheet No.
00C-19, and the connection of base liner system is likely excluding floor area of the
landfill.
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i. Provide the description of the new expanded area (with or without landfill base
floor area).
ii. Add all reference of drawing sheets to the sections.
iii. According to the descriptions in the Permit Application, the construction of new
expanded waste footprint enclosed by the wall – Phase A will likely be completed
by backfilling selected fill material and NOT involve excavating/removing any
portion of existing perimeter berm. Please add the statement to the Section 1.3.2.
iv. The description of the proposed LCR system in Section 1.3.3 is inconsistent with
those in Section 9.1 of the Operations Plan. Please clarify.
v. To connect and extend the baseliner system from the existing landfill unit upward
to the top of the wall, the in-place waste may be exposed for locating the existing
landfill baseliner (as shown on drawing Sheet No. 00C-18).
a. Describe/detail the connection of compacted clay liner and geosynthetic liners
(geomembrane & GCL).
b. Describe the management of the exposed in-placed waste (limited extent per
day and cover requirements – ADC is not allowed) and leachate/run-off and
LFGCCs (oxygen intrusion & head piping relocation)

16. (Section 1.4) Please provide the requested info.
i. According to the industrial data, the minimum thickness of 3-feet of the
temporary haul road for dump trucks (not track equipment) may be required and
maintained over connection point of the liner system. The typical drawing of the
haul road over the existing waste should be provided to the Permit Application.
ii. This Section should discuss the calculations and conclusions on the stability
analysis of the operational cover in K – Operational Cover Veneer Stability of the
Permit Application.

17. (Section 1.5) For the wall integrating to the landfill, the conclusions made from the
design calculations and analyses in J – Geotechnical Data should be incorporated into this
Section.
i. It is evident that the narratives/conclusions of veneer slope stability stated in the
Section are totally different from the results concluded in J & K of the Permit
Application. It is unbelievable that the statement of a minimum friction angle of
8.7 degrees of a final cover system can stably self-stand on a 3 to 1 slope angle.
Please clarify.
ii. This Section should also discuss the global and block/transitional slope stability
analyses of wall integrating into the landfill.
iii. For wall itself, the stability analyses must be properly addressed the internal
resistance generated from the reinforcement (such as geo-grid) and the selected
reinforced fill material. The specified parameters should be summarized in a
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tabular format; and if the data varies by station of segment, please present data
according to the stations or segments.
a. The concluded design parameters for the specified geogrid (material shear
strength, spacing, length, and special considerations for overlapping at wall
termination, connection, turn/altering alignment, etc.)
b. The concluded design parameters for the specified reinforced fill material
such as PI, gradations, shear strength, density, etc.
iv. If the landfill development sequences are as followed: starting waste filling
operation in Phases 1 & 2 after the wall segment Phase A is completed, and the
future Phase 3 surrounded by Phase B wall segment will not be initiated until the
final fill grade reaching certain elevation, said 1000 feet amsl. The CCU should
consider two scenarios of slope stability analysis:
a. Interim slope stability at the Phase 2 (Cells 4 & 5) and the future Phase 3. The
maximum fill height at Phases 1 & 2 must be properly designed to avoid an
interim slope failure (a south to north run).
b. Interim slope stability of the existing external side slopes of the landfill -
Phases 1 & 2 during the wall construction. Many segments of the existing
perimeter berms around east, south, and/or southwest sides of the landfill unit
(likely from Station 0+00 to 53+25 as shown on Sheets C-14 and C-15 in L-
Facility Plan Drawings) are subjected to being excavated and exposed for
connecting the existing landfill base liner system to that at new expansion area
and for accommodating wall and elevated berm. The slope failure resulting
from excavation of a landfill toe is not uncommon. This is becoming a safety
concern; therefore, the CCU must confirm if this construction is considered as
a confined or semi-confined space entry, and a proper safety plan must be
prepared, and safety measures must be executed during the construction.
c. The drawing Sheets C-14 and C-15 must be revised to include more info of
the existing perimeter berm such location of external slope (location and
elevation) which is subject to cutting and filling in the wall project.
d. What is the slope angle of the inboard wall? Will the specified minimum
interface friction angle of 19 degree is applicable for the landfill baseliner
system overlain the inboard wall?

18. (Section 1.7) The portion of the LFGCCs (may include well casing, piping, condensate
sumps, control valves, etc.) are subject to relocation or extension to coordinate with the
MSE wall construction and the landfill vertical expansion. Please describe which
components of the LFGCCs will be subject to relocation/extension and the effects on of
gas production (shut down and restart requirements including reporting). The items and
quantities of the system will be located should be summarized in a tabular format.

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19. (Section 1.8)
i. Provide design calculations to prove the concluded statement “…including the
limited additional lined area that will be constructed as a part of Phase a MSE
wall landfill expansion.”
ii. Please provide the data and calculations to show the existing leachate piping and
storage unit can manage the additional quantity of leachate that will be generated
from the expanded waste footprint.
iii. The tank shall be inspected weekly, not monthly, per Rule 15A NCAC 13B
.1680(c)(4).

20. (Section 1.9)
i. Please detailed the construction sequences (step by step) of the MSE wall
construction coordinating with the proposed lateral landfill expansion (between
the existing waste fill area/berm and the proposed wall). A chart or diagram of
the construction sequence may be required for the clarification.
ii. The SWS will not approve the CCU’s plan to submit an individually certified
CQA report for a completed portion of the entire wall (Phase A) without knowing
the following detailed practices or plans at each terminated/ continued segment.
a. The wall construction sequences from stations to stations and terminated
elevations.
b. The wall construction will not interfere the waste operations.
c. The stormwater and leachate management and practice.
C- CQA Plan
21. Please identify which Technical Specification related to each Section/Contents of the
CQA Plan and summarize (in a tabular format) the testing item, frequency, method, and
minimum passing criterion.

22. The CQA testing for physical properties and engineering parameters of geosynthetic
materials including the landfill baseliner system and final cover system and the MSE wall
system components (geosynthetic reinforcement, earthen material in reinforcement zone)
are not available in the CQA Plan which consequently fails in meeting the requirements
stated in Rule 15A NCAC 13B .1621(b).
a. The passing criteria shall exceed the values concluded from the engineering
design of the Permit Application and per requirement in Rule 15A NCAC 13B
.1624.
b. The CQA Plan should described CQA sampling approaches/methods and the
protocols to manage the situation if the CQA tests fail to pass the minimum
designed values.
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c. The CQA test results for all geosynthetic material for the project shall be
completed before the planned preconstruction meeting for geosynthetic liner
system & MSE wall construction as stated in Section 1.7.3 of the CQA Plan.

23. The CQA program of testing of interface friction angles, between each components of
landfill base liner system and final cover system, are not available in the CQA Plan.

24. (Section 1.3.2) Regarding the MSE wall construction, the qualifications of the
geosynthetic manufacturer (geogrid) and installers are not specified in Technical
Specifications.

25. (Section 1.7.2) The meeting should also discuss the following tasks, but not limited to:
i. Confirm the prepared inspection checklist, construction inspection including the
inspection items, qualification & responsibility of the inspector and reporting
requirements. The confirmed and approved documents should be forwarded to
the SWS five (5) working days prior to MSE wall construction and included in the
certified CQA Report.
ii. Penetration of the MSE wall for installing guard rails, permanent litter control
fencing, subsurface drainage network – utility piping installation, etc.
iii. Subgrade preparation and wall base final grading.
iv. Confirm borrow for the selected fill for subgrade and fill material for constructing
the reinforced zone of the MSE wall. Borrows should be identified and confirmed
according to the QA testing results from subsurface investigation/soil testing
program at the on-site or off-site borrow areas.
v. Drainage network including control run-in toward the footprint of the wall.

26. (Section 1.7.3) In the meeting the testing results of the specified interface friction angles
between the components of liner system should be ready for review and approval or
rejection.

27. (Section 1.7.4) Should the contractors involved with the installation of utility lines and
the relocation of gas piping of the LFGCCs & LCR force-main, and other tasks be
participating the meeting(s) when the scheduled tasks will be conducted?

28. (Section 2) Provide specifications for the protective soil layer component of the landfill
base liner system.

29. (Section 2.2 - Soil) The Section should discuss MSE wall foundation preparation which
may incorporate as the basis or minimum criteria for evaluation and determination if the
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fill material or in-situ material are satisfactory to the conclusions and recommendations in
J- Geotechnical Data & I- Technical Specification 31 23 00 – Earthwork.
i. The foundation for the wall shall be graded level for a width equal to or exceeding
the length of soil reinforcement or as shown in the drawing. A data table
summarizes the extent of wall base area need to be prepared vs. the stations of
wall alignment is required.
ii. On the backside of the wall, an earthen berm will be constructed as landfill base,
the coordination of construction sequence between preparations of wall
foundation and the landfill base liner system/earthen berm shall be clearly
described in the plan.
iii. Grading requirements to facilitate drain storm/surface water away from the wall
structure. The layout (along the wall alignment) and profile of the wall, identified
by survey stations, that show the existing grades and final grades are required in
the Permit Application. Any drainage system associated with surface water
collection, conveyance, or storage should be present on the drawing (s). The
requested drawing(s) – Contract Drawings specified in Technical Specification 31
23 00 should be included in the permit application for a of NC storm water
permit.
iv. The QA testing of the wall foundation material. The drawing Sheet 00C-?? and
Section 1.1 of the Engineering Plan state the MSE wall will be sit on the top of
the existing perimeter haul road.
a. Will the existing road be regraded? How?
b. If the wall base wider than the existing road, what kind of foundation
material will be used, granular road base material or soil?
c. Will differential settlement be a concern if two different foundation
materials are used as the foundation soil? Provide settlement analysis to
demonstrate the responses.
d. The testing items on borrow material for all earth work should include all
foundation design parameters in J & K of the Permit Application. The
testing methods and frequencies of QA test menu shall be described in the
CQA Plan
v. Specify the minimum compaction effort (clayey soil) or relative density (granular
soil, if the existing road base will be used as foundation soil) on the foundation
soil based on the QC testing requirements. The compaction equipment to be used
and the minimum number of passing should describe.
vi. Prior to constructing the first layer of the MSE wall, the MSE wall sub-consultant
(Tensar Corporation) must confirm in writing that wall foundation has been
prepared and compacted to the elevations and grades according to the wall design
and CQA plan. The acceptance document should be appended to the certified
CQA report.
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30. (Sections 2.2.1 & 2.2.2) Which is the project specification referring to? Section 31 23 00
– Earthwork?

31. (Section 2.2.3) The Technical Specification does NOT contain any specified section
regarding the material & construction specifications of Vegetative Support Soil or topsoil
layers.

32. (Section 2.3) Per Rules 15 NCAC 13B .1624 & .1627, test pads for both landfill baseliner
and final cover systems must be properly constructed and tested. This Section does NOT
provide any test pads CQA requirements.

33. (Section 2.3.1.) This Section should discuss the CQA requirements for the subgrade of
the landfill baseliner as well per Rules 15 NCAC 13B .1624(b)(4) & (7) & the selected
design parameters (such as density & shear strength, etc.) in the landfill designs – bearing
capacity, settlement analysis, slope stability analysis.

34. (Section 2.3.2)
i. The Section shall be more specific which Technical Specification is referring to.
ii. The Section specifies that QA testing on soil liner material at a frequency of
approximately 10 percent of requested CQC tests which SHALL include all tests
that are listed in table in Part 3.3B of Section 31 38 10-7. Please confirm this is
the intent in Section 2.3.2 of the CQA Plan.

35. (Section 3 - Geomembrane Installation)
i. This Section shall describe the geomembrane (type- HDPE & LLDPE, texture vs
smooth, thickness) to be used in the landfill project.
ii. (Section 3.2.2) The subsurface acceptance certificate should be included in the
certificated CQA report.
iii. (Section 3.2.3)
a. The Section 1.7.3 describes the pre-construction meeting regarding
geosynthetic liner & material for the project. Please correct typo.
b. There is no Section 3.2.3.1 in this Section 3.2.3. Please describe the
context of Section 3.2.3.1.

36. (Section 4 - LCR)
i. The leachate force-main is subject to relocation; therefore, the CQA for material (if
the new force-main will be used) & construction of force-main is required; especially,
the hydrostatic testing requirements.
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ii. The existing riser inside the sump will be extended to the top of MSE wall. The
extension length for each riser should be specified.
iii. Will the existing pump at each sump be replaced due to additional lift generated from
the extension of the riser?

37. (Section 5 - Geotextile)
i. (Section 5.1) Does ASTM standard define “Minimum Average Value?” Is there a
reason why the project uses the FHAW definition in landfill project?
ii. Geotextile will be used for separation, cushion, and filtration purposes in this
project; therefore, the specific properties for each described function shall be
listed in this Section.

38. (Section 6 - HDPE Manhole, Piping & Fitting)
i. Does the project require HDPE manhole? Please specify the location (s).
ii. The leachate force-main is subject to relocation; therefore, the CQA for material
(if the new force-main will be used) & construction of force-main is required;
especially, the hydrostatic testing requirements.
iii. Riser, pump
iv. Will this section cover the LCR force-main and riser? The Section 6.1 shall list all
related material, specified length, diameter, rating, strength, etc.
v. Provide detailed pressure testing protocols and testing methods.

39. (Section 7- HDPE Geonet)
i. The title is misleading. The material proposed to be used are NOT geonet but
geocomposite drainage material per Specification Section 31 32 18. For the sake
of consistency, revised the title of the Section 7 and replace “geonet” by
“geocomposite drainage material.”
ii. This Section should specify the CQA testing requirements. The Section 7.2 states
that the CQA consultant will examine all manufacturer’s certification to ensure
that the property values listed on the certifications meet or exceed the project
specification.
a. Please state which project specification(s) should be followed.
b. Without conduct any CQA test on the received material, the CQA Plan fails in
meeting the requirements stated in Rule 15A NCAC 13B .1621(b).
iii. (Section 7.8) This section shall specify the minimum thickness (in feet) of
soil/earthen material shall be placed over the in-place liner material prior to
allowing the specified vehicle or machinery (rubble tires or track) to construct the
following layers – a protective soil cover (base liner system) or a vegetative
support layer (final cover system).

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40. (Section 8 - GCL)
i. (Section 8.1) MARV is defined in the ASTM D4439.
ii. Please add the ASTM D 4873 should be followed for labeling, shipping, and storage
geosynthetic material to the Sections 8.2 & 8.3.
iii. Part 1.4A.2. of Specification Section 31 05 19 specifies the GCL sample for CQA
testing. The Section 8 shall provide CQA test on GCL, which should include the test
items, frequencies, and methods and passing criteria.
iv. GCL (Section 31 05 19) does not provide the specification of placement of soil
material on top of the GCL. Please add the requirements to this Section or to the
GCL specification - Section 31 05 19.

41. (Section 9 – Geogrid & Section 10 – MSE Wall)
i. For geogrid, Section 9.2 shall meet the same requirements as stated in Section 3.1.
ii. (Section 9.6)
a. The penetration through the geogrid layer shall be discussed.
b. The special requirements for placement of geogrid at curvature locations.
iii. (Section 9.8)
iv. According to Section 10.1 the MSE wall subconsultant shall provide the geogrid
CQA and specification for the project. Therefore, Section 9 may be used as the
guidance to review the package submitted by the MSE wall subconsultant when
the package is available.
v. Section 10.1 states that detailed design of the MSE wall is the responsibility of the
MSE Wall subconsultant. Therefore, the MSE wall sub-consultant (Tensar
Corporation) shall provide the individual wall design package including the
CQA Plan & drawings consistent to the Technical Specifications and wall design
in the Permit Application. The Permit Application provides wall packages made
by HDR and Tensar, which creates confusion of which one is the final design of
the wall. The Permit Application shall have the final MSE wall submittal
completed by the MSE wall sub-consultant and this individual submittal shall
include, but not limited to,
a. Wall design [(including theories, assumptions & utilization of J-Geotechnical
Data in the Permit Application, detailed calculations (an illustration/example
of wall design is required if the computer software package is used for
design), and references]. Pay special attention to lateral earth pressure
coefficients used for wall design. The wall will resist lateral pressures from i)
both earthen berm (non-reinforced or retained soil/inboard wall of the MSE
wall and municipal soil wastes which shall consider the density increase with
ages and depths) and ii) dynamic/machine-induced pressures from landfill
operations.
b. The CQA Plan & Technical Specification for the wall components.
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c. Drawings.
i) The layout (plan view) and elevation view (elevations above mean seal
level based on on-site survey benchmarks and widths) of the wall – Phase
A by survey stations.
ii) The cross-sections to detail geosynthetic reinforcement info (type,
strength, length) by segments (stations to stations, elevations, etc.) and
reinforced soil engineering parameters, dimensions of each lift/course.

42. (Section 11 – Survey)
i. The following testing (including failure ones) and repair locations of all liner
components should be surveyed and included in the certified CQA reports:
a. liner systems: HDPE (base liner), LLDPE (final cover), GCL, and
geosynthetic drainage composite and compacted soil liner.
b. locations/alignments and gradient of LFG piping and components (sumps &
valves).
ii. The MSE wall survey requirements and items including as-built data and
drawings are not available.
iii. (Section 11.7) This section should specify the measurement of a layer thickness at
the sloped area.
iv. (Section 11.9) The mentioned Paragraph 9.5 is either irrelevant or not available in
the CQA Plan.

43. (Section 12 – Documentation)
i. (Section 12.2.3) The non-conformance documents shall be included in the
certified CQA report.

ii. (Section 12.4) The changes or modifications of designs and project specifications
including QA/QC testing shall notify the SWS for a review and approval. All
changes, modifications, and deviations from the approved design, plan, or
specification shall be documented and included the certified CQA Report. Please
add the requirement to this section.

iii. (Section 12.6) Please provide a “Table of Content” of the CQA report for this
landfill expansion & MSE wall project which lists all components, according to
the CQA Plan and Technical Specification.

D. Operations Plan
44. (Section 1) Please provide the drawing number (s) for the referenced landfill existing
conditions, proposed expansion areas, the fill phasing, proposed final contours, and
erosion control plans.
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45. (Sections 3) Wastewater treatment sludges are allowed for co-disposal with other
permitted waste streams according to the Rule 15A NCAC 13B .1626(1)(e). The
wastewater treatment sludges meet the following requirements may be disposed at the
landfill.
i. do not contain hazardous wastes or PCBs which are confirmed by analytical tests –
US EPA test methods SW-846,
ii. come from the known resources inside landfill service area, and
iii. satisfy the free-liquid requirement in Rule 15A NCAC 13B .1626(9)(c).

46. (Section 3.3) The landfill shall not accept wastes for disposal according to Franchise
Agreement and NCGS 130A-309.10(f). Please add the requirements to this Section.

47. (Section 3.4) The Contingency Plan should discuss how to manage the prohibited /
nonconformance wastes when they are left at/by the working face and waiting for the
responsible person(s) to properly dispose of or the responsible person(s) can’t be
identified in a short time period.

48. (Section 4.1) The repaired liner system must be tested according to the approved CQA
Plan and Technical Specification. A written report should be submitted to the SWS for a
review and approval.

49. (Section 4.2) The working face at the expanded areas is confined or sandwiched by the
MES wall/inboard slope (3 to 1) and the existing wastes in Phases 1 & 2. Will the waste
disposal procedures be different from those described in the Section? The Section should
address the following concerns, but not limited to:
i. Haul road locations relative to the fill sequences at the expanded areas should be
discussed.
ii. The unloading waste and turning around for a waste vehicle may be limited or
restricted by the narrow working face at the expanded areas, the traffic control
and turn around area should be discussed.
iii. Procedures to protect the existing LFG collection wells and lateral piping/valves
from waste operations on the exterior side slopes of the Phases 1 & 2.
iv. How to manage the existing vegetation and intermediate soil cover over the in-
place waste on the exterior side slopes of the Phases 1 & 2.
v. Stormwater and leachate separation device (s) – GRC specifications and berms/
stormwater management system.
vi. Drawings including typical details as supplement pertaining to the above
narratives from items (i) through (v) are required.

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50. (Section 6) On July 23, 2018, the CCU requested to relocate the establish a CAB
collection area from landfill - Phase 3 area to a new area (approximate 2 acres) by the
White Goods/Scrap Metal Collection Area as shown on Sheet 00G-003. The request was
approved by the SWS. The latest Facility Compliance Inspection Report states the CAB
is operational at the new location and the CCU plan possible lateral expansion of the
collection site. Please state the current status of the CAB unit in the Section.

51. (Section 7) The SWS hydrogeologist requests a submittal of individual landfill gas
monitoring plan for review and approval. The guidance for preparation of the plan can be
found in the link -
https://files.nc.gov/ncdeq/Waste%20Management/DWM/SW/Field%20Operations/Envir
onmental%20Monitoring/LandfillGasMonitoringGuidanceDocument.pdf.

52. (Section 8) The proposed wall construction and modification of the approved BMPs for
stormwater management system for final cover system should obtain an approval from
the NC Land Quality section. The approved documents and permits should be appended
to the Operations Plan.

53. (Section 9.1) The second paragraph of the Section states that “the inboard slope of the
MSE wall will continue the existing 3H:1V lined inboard slope of the perimeter berm to
the top of the MSW wall.”
i. Add the drawing Sheet No. 00C-20 as reference.
ii. Will the described construction approach be only applicable at the existing sump
area or applicable for all new expanded waste footprint enclosed by MSE wall -
Phase A? Please revisit the Section 1.3 of the Engineering Plan and have the
consistent descriptions of the baseliner and LCR system throughout the Permit
Application.
iii. Add the reference of the alternative baseliner system as shown drawing Sheet No.
00C-19.

54. (Section 9.6) Regarding the stormwater separation at the new expanded disposal area
between inboard wall/berm and the existing disposal area (Phases 1 & 2), please show the
typical stormwater/leachate separation device (including GRC & temporary sump) and
landfill base liner connection on drawing.

55. (Section 13) The following document shall be placed in the operating record:
i. Permits and the approved permit applications including as-built document for
landfill construction and closure activities.
ii. Fire occurrence reports, open burning permits/approval documents.
iii. Amount of leachate generated and leachate line cleaning/flushing records.
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56. (Section 14) MSE wall inspection should be conducted at three different periods: during
the construction, after the wall completion & initiating landfilling, and inactive & post-
closure period. Inspections conducted at each period should be described and an
inspection checklist should be prepared individually and appended to the CQA Plan,
Operations Plan and Post-Closure Plan. The inspection items should be routinely
modified according to the on-going changes of the site situation.
i. Inspection of the wall during the construction period that is part of the QA/QC
processes shall be the responsibility of the wall contractor and the Engineer on
behalf of the CCU according to North Carolina Building Codes (specifically
Chapter 17- Special Inspections, referring Comment No. 3d). The inspection
report shall be appended to the certified CQA report.
ii. Inspection of the wall during the operational period & post-closure may be
conducted by the landfill employee or the third party.
a. Describe the minimum requirements of training credential and experience of
MSE wall inspections.
b. Please define the triggering point when the wall requires repairs – the
measurement of wall displacement – vertical settlement, lateral movement
(longitudinal and converse directions).
c. Describe any requirement according to building codes or ordinances.

57. (Section 14) The MSE wall constructed with geosynthetic reinforcement (such as geogrid
or geotextile) can be significantly more flexible and extensible than metallic
reinforcement. The visual inspection described in this Section & Appendix D of the
Operations Plan will be helpful but can’t quantify the severity of wall movements (either
lateral displacement or vertical settlement) and provide an early warning of wall failure
or demonstrate the anticipated by calculated settlement (as stated in Section 6.3 of J –
Geotechnical Data of the Permit Application) will be completed. The CCU shall provide
more sophistical monitoring plan by
i. Installing adequate amount of instrumentations (such as settlement plate, slope
indicator, strain transducers, or devices with equivalent function) or surveyor
monuments at the suitable locations to monitor and document the wall movement
throughout the lifetime of the landfill. A monitoring plan, at a minimum, includes
the monitoring items, location, frequency, instruments/devices/equipment,
technician qualification, data collection & reduction, and report contents of each
monitoring event, etc. The report shall be certified and signed/sealed by a
professional engineer who is registered in the State of North Carolina.
ii. Preparing a contingency plan for managing waste should the wall fail. The plan
may include, but not limited to:
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a. The CCU should use the available computer model (such as material point
method or other equivalent model) to estimate the maximum run-out distance
if the MSE wall fails. The worst scenario case should be evaluated, and the
results from the evaluation may be assisting the preparation of the
containment system required by the Contingency Plan
b. Based on the current available theories and calculations to establish the
maximum quantities of the lateral and vertical movements of the wall.
Appling a selected factor of safety to the define the triggering point to alarm
the CCU taking all necessary actions to prevent the wall structure failure. The
requested monitoring and safety mechanism MUST be established and
implemented on the wall segments paralleling the railroad and Grassy Creek.
c. Reporting and notification requirements to SWS and other parties will be
impacted by the waste exposure – the company owns nearby railroad, the
agencies (both the State and local government) manage the nearby Grass
Creek. The time frame of a verbal and a written notification/report should be
provided.
d. Containment system to retain the wastes within the landfill property and
isolate, confine, and cleanup the waste if the wastes move outside the landfill
property.

58. (Section 14.1)
i. The training, experience, and education credential for the inspector should be
specified. This inspection frequency and inspector credential may have to satisfy
local building code as well. Please provide requirements based on the NC State
Building Code or the City ordinance requirements; whichever is stricter.
ii. The visual inspections should include
a. The presence of cracks in reinforced fill at the top of the wall, on the exterior
or inboard slope of the wall, or on haul road surface on top of the wall.
b. The inclined guardrail or utility pole(s), if any.
iii. In addition to the notification requirements, the Section should set a schedule for
assessing the observed problem (s), preparing/submitting an action plan to fix
each observed problem, the follow-up reports. The “as soon as” is not acceptable
schedule for both Sections 14.1 & 14.2.

59. (Section 14.2)
a. The Operations Plan shall discuss the measures and accesses to manage windblown
trash, vegetation management, and maintenance/repair activities associated with the
MSE wall. In addition to the stated activities in the Section, the plan should also
address the concern of litters/trashes which are carrying by wind and falling, lodging
or hanging on the exterior side of the MSE wall. The portable and permanent litter
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fences may not be 100% capturing wind-blown litter. The CCU should design a path
or paths to safely access the wall structures and conduct the described activities.
Inaccessibility should not be an excuse for not implementing the planned activities.

60. (Appendix D) MSE wall inspection form. The following areas, but not limited to, should
be added to the inspection items.
i. Facing Unit.
a. Sign of vandalism.
b. Burrowing animals
ii. Top of the wall
a. Longitudinal or transverse cracks – locations, depth, length & width; exposure
of geosynthetic reinforcement.
b. Washing out or erosion at the area adjacent to discharge of slope drain or
perimeter channel overtopping
c. Settlement around the drop inlet/catch basin in the perimeter channel due to
downdrag force (negative friction) on the precast concrete manhole pipes.
iii. Energy dissipator at the discharge end of drop inlet
a. Trashes or obstructions.
b. Signs of erosion or stains.
G- Closure Plan
61. (Section 1)
i. This Permit Application requests an approval of new waste footprint of 70 acres
in the MSWLF - Phase A as shown Table 1 of the Facility Plan. Please explain
why the maximum area requiring a cap is 58 acres, not 70 acres in both Sections 1
& 4 of the Closure Plan.
ii. The descriptions of the alternative final cover system do not provide the whole
history of the submittals of the permit modifications and status of review
processes. Please detail the current status of the permit application and provide
the related documents after 2016 (DIN28113 & 28805) in Appendix A.

62. (Section 2) Provide the referenced of the MSE Wall Geotechnical Report.

63. (Section 3) What is the slope of the final cap? What is the maximum grade/elevation,
and why this grade is selected?

64. (Sections 5 and 6)
i. The modifications to the previously approved stormwater and erosion control
system, including hydraulic designs and calculations (K & L of the Permit
Application) for the MSE wall construction & the revised landfill final cover
(integrating wall to the final cover system), should be approved by the NC Land
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Quality Section. The approval document and permit shall be appended to the
Permit Application.
ii. Provide detailed descriptions of the proposed BMPs shown on the drawings, such
as the discharge end of downslope drains, impermeable perimeter channels, anti-
splash barrier, perimeter channel drop/structure, etc.
iii. Based on the stormwater calculations (K-Calculations), can the existing sediment
basins accommodate the design stormwater flow generated from a 100-year storm
event?

65. (Section 7) The narrative in the last sentence of this Section is questionable and
contradict to the narrative in Section 4.3 of the Post-Closure Plan.

66. (Section 12) This Section may want to discuss the submittal of the modification of the
closure plan and finalization of the components of the landfill cover system as stated in
Sections 1, 2, & 4 of the plan. The submittal of the revised plan to SWS for a review and
approval shall be no later than 90-working days prior to closure activities.

H- Post-Closure Plan
67. (Section 4) Please provide the requested info below:
i. Table 1 should add the leachate breakout as the inspection item. The inspection
frequency shall be described.
ii. Describe the leachate breakout notification requirement per Rule 15A NCAC
13B. 1604(b)(2)(L)(iii) and follow-up actions to investigate the impacts on
environment media – soil, sediment and water quality.
iii. Discuss the measures to remediate leachate outbreak.

68. (Section 4.7) When the landfill gas capacity is not economically feasible for the LFGTE
project, this Section shall discuss the gas treatment option such as directly release gas to
atmosphere or destroy the gas by a flare or flares. The costs for each option should be
added to the cost estimates.

69. (Section 5.1) Inspection frequency for the leachate outbreak and stormwater BMPs shall
include the non-scheduled inspection - after the major storm event is occurred.

70. (Section 5.2) The on-going groundwater corrective action at the landfill facility shall be
briefly discussed.

71. (Appendix C Post-Closure Cost Estimates)
i. The costs associated with closing leachate tank facility according to Section 4.5
per Rule 15A NCAC 13B .1680(f).
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ii. The cost of decommissioning the landfill gas to energy system (LFGTE) as
described in Section 9 of the Closure Plan should be included in the cost
estimates. Although the operations of the LFGCCS and LFGTE by an
independent contractor, the CCU is ultimately responsible for the system
decommissioning costs.
iii. Financial assurance for long-term performance, inspection/monitoring (in Section
5.1), and repair. According to GRI Report No. 40, the average cost to remediate
excessively deformed or collapsed MSE wall or berms is almost twice the initial
cost of the construction. CCU must provide sufficient and adequate financial
assurance (FA), in addition to the existing FA required by Rule 15A NCAC 13B
.1628 and N.C.G.S. 130A-295.2, to cover costs for
a. Long-term inspection and monitoring MSE wall performance and safety.
b. Cleanup any solid waste that shifts outside the waste footprint,
reconstructing wall, removal and disposal of spilled wastes, and any
damaged to the nearby environment (including Grassy Creek) and
infrastructures (utility lines, railroad, etc.).
c. Replacement of the wall when the service life is reached. The landfill and
wall are perpetual establishments but the service life of the MSE wall will
only last for 70 years per AASHTO publications. The wall replacement
and removal and disposal or temporary storage of in-pace wastes during
wall reconstruction are inevitable costs must also be considered while
preparing FA. The cost to construct Phase A wall segment should be
included in the Post Closure Cost Estimates.
d. The cost of 2 million dollars for potential assessment and corrective action
per NCGS 130A-295.2(h) is not included in the Post-Closure Estimates.
e. The costs for on-going groundwater remedial and corrective action is not
included in the Post-Closure Estimates.
I - Technical Specification
72. The specifications should also include the following tasks:
i. Construction of a temporary path/haul road on the existing landfill unit – exterior
side slope of the Phases 1 & 2.
ii. Intermediate soil cover (upper 6-inch cover material may be converted into
compacted soil liner per Section 2.3.1 of the CQA Plan).
iii. Survey requirements for the MSE wall/landfill expansion project.
iv. HDPE – Perimeter Drainage Channel/Catchment.
v. Drop Inlet/Precast Concrete Manhole.
vi. Haul Road/Ramp.

73. (Section 01 30 00)
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i. The Section Part 1.10 specifies the survey requirements which are considered as
incomplete requirements. Please prepare a Section to specify more complete
survey requirements for this landfill/MSE wall project.
ii. (Part 2.1D) The specified testing method ASTM D5321 is not applicable for
testing interface angle between GCL and soil or other geosynthetic material.
iii. (Part 2.1 C & D) The Parts should specify testing requirements for both landfill
baseliner and final cover systems.
iv. (Part 2.1E) The specified minimum interface angle of 21 degrees is NOT
consistent with designs and calculations present in the Permit Application. The
specified minimum interface angle 0 be summarized in a tabulate format
including specified materials used at different area, minimum interface angle, and
testing method and frequency.

74. (Section 31 10 00) This Section should specify the site-specific cleaning requirements at
the existing landfill unit – exterior slopes of Phases 1 & 2, haul road, relocation or
removal lines – utility, LCR force-main, LFG wells & header piping, stormwater BMPs
and drainage channels, etc.

75. (Section 31 05 19 - GCL)
i. (Part 1.2A) ASTM D 6243 – “Test Method for Determining the Internal and
Interface Shear Resistance of Geosynthetic Clay Liners by the Direct Shear
Method” should be added to this part.
ii. (Part 1.2B) Specify the GCL installer’s qualification and experience.
iii. (Part 1.3A) The GCL manufacturer shall provide a certification that the
manufactured GCLs are broken needle-free concluded from continual MQA,
100% inspection, and removal of any needles or metal debris.
vi. (Parts 2.2B & 2.2C) The specified testing method ASTM D5321 is not applicable
for testing GCL shear strength & interface angle between GCL and soil or other
geosynthetic material.
vii. (Part 3.1B.3) Define the excessive wrinkle with a maximum numerical
measurement (such as 5 inches). What happen if the excessive wrinkle is present?
viii. (Part 3.1B.7) Specify the bentonite spreading rate at seamed area -pound per
linear feet.

76. (Section 31 23 00 - Earthwork)
i. Define “Soil Engineer” in this Section whose job description/responsibility and
qualification are not available in the CQA Plan.
ii. (Part 2.1A) Should this Part be coordinated with conclusions and testing results
from the on-site borrow pit study (BSCS)?
iii. (Part 2.1B)
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a. If the structural fill is used for constructing landfill subgrade and berm
intimately connecting to the MSE wall, the material should be tested for
density, density & moisture relationship (Standard Proctor), plasticity index
(Atterberg limits), and soil shear strength (both cohesion and friction angle)
which should either be equal to or exceed the value concluded from the slope
stability analysis - both global and veneer slope stability analyses. Please list
the CQA testing items, methods, and frequencies and passing criteria.
b. What is the frequency and testing method for testing fill grain size
distribution?
c. Why the structure fill is not be tested for material consistency such as
plasticity index (PI), moisture content, unit weight/density, and shear
strength? Please add the test items to the QA/QC testing including test
methods and frequencies and passing criteria based on the veneer slope
stability design parameters.
iv. (Part 3.1A) Add the following requirement to this part.
a. To identify and confirm the locations of the existing LFGCCs piping/header
and LCR piping & force-main shall be included in this part.
b. To remove the existing waste edge markers, slope drainpipes and to construct
a temporary haul road over the in-placed waste along the exterior side slope of
Phase 1 should be specified in this part.
v. (Part 3.2D) According to Part 2.1B, the fill material shall have maximum size of 3
inches; why will this Part allow soil with grain size over 3 inches being used?
Please clarify.
vi. (Part 3.4) The field QC testing on the in-place compacted fill must include testing
items (in-place moisture & density) methods, and frequencies. The testing
locations and testing results (including the failure ones) shall be documented in
the certified CQA report.

77. (Section 31 23 33 -Trenching, Backfilling, and Compacting for Utilities)
i. This specification shall be project specific- regarding installation of LCR force-
main, LFG header, condensate/air lines, subdrain, utility lines inside/adjacent to
the MSE wall structure. The specified material shall be consistent to the
submitted drawings. Please revise the specification accordingly.
ii. (Part 1.4A.4) What types of granular materials are specified here? NCDOT #58,
78M or those described in the Permit Application.
iii. (Part 2.1A.) Is the correct density and moisture method specified? Referring Part
3.3A of this Section.
iv. (Part 3.1A.) Define “Soil Engineer” in this Section whose job
description/responsibility and qualification are not available in the CQA Plan.
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v. (Part 3.2B.3) The Specification 33 05 16 is not available in the Permit
Application.
vi. (Part 3.2B.3) The drawings in the Permit Application do not contain any info of
trench/backfill tasks – dimensions of a trench, backfill material or depths, caution
taps, etc. Please add the info and trench details for installing each piping for this
project.
vii. (Part 3.2D.2.e) Is the specification Division 26 relevant to the project?
viii. (Part 3.4) Installation of plastic marking tapes/warning tapes shall be specified
including, but not limited to, the tape type (color code per Part 1.3A of Section 40
050 00 & tracer wire requirements), depth below the finish grade, etc.
ix. (Part 3.6) What testing methods are going to use for testing in-place density?

78. (Section 31 32 18 – Drainage Composite)
i. The drainage composite material (DCM) will be used at both landfill baseliner
system and the final cover system of the landfill project. Will the specification be
applicable to both system? Please elaborate more.
ii. (Part 1.4A.2)
a. The manufacturer’s document should be a mill certificate or affidavit signed
by a legally authorized official of the manufacturer for the material attesting
that raw material sand roll materials comply with the required physical and
manufacturing requirements.
b. The manufacturer shall provide a certification that the manufactured DCM are
broken needle-free concluded from continual MQA, 100% inspection, and
removal of any needles or metal debris.
iii. (Part 1.5A.) The described Specification Section 01 65 500 is not available in the
Technical Specification.
iv. (Part 2.2) What are the specified test frequencies?
v. (Part 2.2C.2 & Part 2.3A)
a. Is the specified transmissivity value applicable to both LCR and final cover
system?
b. Is the specific transmissivity value satisfactory the conclusions/calculations
from the Appendix A - Final Cover Veneer Stability of K – Calculations of
the Permit Application?
vi. (Part 3.2)
a. Specify orientation of the roll-out DCM in corresponding the predominate
flow direction that the DCM designed for transmitting.
b. Specify the measure(s) from DCM with excessive wrinkles.
c. Specify the maximum distance between ties or space between fasteners in
anchor trenches.
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d. Specify how to seam & overlap the geotextile layers/components of the two
adjacent DCM.
e. The cover placement that should be specified for both landfill baseliner and
final cover systems is NOT available.
f. The requirements of deployment of DCM in anchor trench and anchor trench
backfill are not available.

79. (Section 31 32 19- Geotextile)
i. (Part 1.5A.) The described Specification Section 01 65 500 is not available in the
Technical Specification.
ii. (Part 2.1B.) The described Specification Section 01 25 13 is not available in the
Technical Specification.
iii. (Part 2.2.A.4) The frequencies for the specified MQA testing are not available.
iv. (Part 3.2)
a. Part 3 does not include test seam specification including frequency.
b. There are no drawings show the location or specification regarding heat track
the geotextile overlap.
c. Which Part(s) of Section 31 23 00 specifies the fill placement and compaction
of the anchor trench.

80. (Section 31 38 10 – Compacted Soil liner)
i. (Part 1.2A) All testing methods specified in the Section should be listed in this
Part.
ii. (Part 1.3) Section 1 33 00 is not available in the Permit Application.
iii. (Part 2.1B.1) The soil classification shall be identified by soil lab testing of
ASTM D2487 as stated in the Section, not visual method of ASTM D2488.
iv. (Part 2.1C) Specify the maximum hydraulic conductivity value for soil liner.
v. (Parts 2.1 & 2.2C) The soil density and shear strength should be tested to confirm
that the test results meet or exceed the design parameters used in the engineering
designs for landfill liner systems. Part 2.1 should specify the minimum values of
soil density and shear strength.
vi. (Part 3.1)
a. Soil sample(s) collected from the test pad/strip should also be tested for shear
strength. Please provide the test frequency and method.
b. This Part should specify the construction procedures of placing/compacting
soil liner layer at the sloped areas.
c. The compacted soil line will be placed over, as a subgrade, by a geosynthetic
liner material – GCL (base liner); therefore, the acceptance/certification of the
liner subgrade shall be specified per Rule 15A NCAC 13B .1624(b).
d. The specification for constructing anchor trench is not available.
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e. (Part 3.3D) The index test – Atterberg limits may be waived for specified
testing requirement due to the test results of a hydraulic conductivity if the
same sample is used for both tests.

81. (Section 31 38 25 – Operational Cover)
i. (Part 1.3A) The Section 01 33 00 is not available in the Technical Specification.
ii. (Part 3.2C) The gradation of soil material used for the 24-inch-thick operational
cover at the sloped area should be tested to ensure the selected gradations being
designed for not clogging the underlaying geocomposite material per Rule 15A
NCAC 13B .1624(b)(13).

82. (Section 31 38 30 – Cap Compacted Soil Liner)
i. (Part 1.2A) All testing methods specified in the Section should be listed in this
Part.
ii. (Part 1.3) Section 1 33 00 is not available in the Permit Application.
iii. (Part 1.5A) Specify the tolerance of the finished grade.
iv. (Part 2.1B.1) The soil classification shall be identified by soil lab testing of
ASTM D2487 as stated in the Section, not visual method of ASTM D2488.
v. (Part 2.1C) Specify the maximum hydraulic conductivity value for soil liner.
vi. (Parts 2.1 & 2.2C) The soil density and shear strength should be tested to confirm
that the test results meet or exceed the design parameters used in the engineering
designs for landfill liner systems. Part 2.1 should specify the minimum values of
soil density and shear strength.
vii. (Part 3.1)
a. Soil sample(s) collected from the test pad/strip should also be tested for shear
strength. Please provide the test frequency and method.
b. (Part 3.1A.7) If the different compaction effort is approved then, the soil
strength and density shall be retested to confirm that the test results meet or
exceed the designed parameters used in the Slope Stability Analysis including
the veneer slope stability analysis.
c. This Part should specify the construction procedures of placing/compacting
soil liner layer at the sloped areas.
d. The compacted soil line will be placed over, as a subgrade, by a geosynthetic
liner material –LLDPE (final cover); therefore, the acceptance/certification of
the liner subgrade shall be specified per Rule 15A NCAC 13B .1624(b).
e. The specification for constructing anchor trench is not available.
viii. (Part 3.3D) The index test – Atterberg limits may be waived for specified testing
requirement due to the test results of a hydraulic conductivity if the same sample
is used for both tests.
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ix. (Part 3.3B) The note “*” shall only be applicable for Field Density Acceptable
Criteria.

83. (Section 31 38 35– Erosion Control Layer)
i. (Part 2.1) The minimum thickness of the Erosion Control Layer should be
specified (ref Part 3.2D). The thickness measurement at the sloped area should be
clearly defined.
ii. (Part 2.1A.2)
a. Does the specified gradation meeting the filter design of the underlying
geocomposite drainage material?
b. According to this Part the specified material for the Erosion Control Layer is a
cohesive material. The testing method for permeability of the specified
material is likely not applicable.

84. (Part 3.C.2.a) The specified compaction effort of the soil sample tested for permeability is
not consistent to the field compaction effort specified in Part 3.1D.4.

85. (Section 31 38 40 - Geosynthetic Reinforcement – MSE Wall)
i. The specification of geogrid or geosynthetic reinforcement should have the Part
of “Qualifications” (for manufacturers and installers), “CQA Plan
Implementation,” and “Definition” as those being specified for other geosynthetic
material – geomembrane, GCL, geocomposite drainage material, geotextile.
Additionally,
a. The machine direction (MD) and cross-machine direction (XMD) of
deploying or installing geosynthetic reinforcements at each layer of the wall
system must be defined clearly.
ii. (Part 1.3)
a. The specified requirements of Part 2.01(B) for acceptable geosynthetic
reinforcement (geogrid per data on drawing Sheet 48 of 52) including tensile
strengths measured by ASTM D6637, joints, seams shall be clearly refenced
in the Specification. Please provide the specified requirements. Additionally,
the data of the geogrid that is evaluated and approved by National
Transportation Product Evaluation Program (NTPEP) should be provided
according to the NCDOT Guidelines for the Geogrid Evaluation Program
(DOT Evaluation Program) dated April 26, 2013 and the latest amendment;
the data tested include at both MD and XMD, in additional to those in Part
2.1, but not limited to: Reduction Factors (AASHTO PP66), Pullout
Resistance (ASTM D6706), Direct Shear (ASTM D5321), Joint Strength
(ASTM D7737).
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b. The geogrid specified for this MSE wall project should have been reviewed
and approved for use for an MSE wall project by either NCDOT or any other
neighboring state DOTs through the DOT Evaluation Program for use within
one (1) year before this landfill construction project. The approval document
issued by the state DOT should be submitted under this Part and appended to
the certified CQA Report.
c. The specified Part 2.02 is not available in the Specification.
iii. (Part 1.4)
a. “Minimum Average Roll Values” is also defined in ASTM D4439.
b. CQA product conformance testing on the geosynthetic reinforcement should
include sampling procedure according ASTM D4354.
c. To meet the specification requirement in Part 3.1F, the ASTM method(s) to
test moisture contents on compacted fill is (are) required.
d. Add ASTM D5818 “Practice for Exposure and Retrieve of Samples to
Evaluate Installation Damage of Geosynthetics” to this Part.
e. Add ASTM D6706 “Standard Test Method for Measuring Geosynthetic
Pullout Resistance in Soil” to this Part.
iv. (Part 2.1) In addition to MQA program specified in Part 2.6, a Part specifying the
CQA testing on geosynthetic reinforcement (both primary and face wrapping
geogrid) as sated in Part 2.5C of the Specification & Section 1.7.2 of the CQA
Plan should be described and implemented prior to order the selected material.
Please describe the CQA program in this Part.
v. (Part 2.1.A.4)
a. The composition of geogrids (both primary and secondary geosynthetic
reinforcements) should be specified, which may include, but not limited to,
manufacturing process (extrude, woven, or welded), testing methods &
criteria - polymer class & grade (ASTM D1248), melt flow (g/10 min by
ASTM D1238), carbon black (ASTM D4218), weight range (g/m2).
b. There are six (6) different types of uniaxial geogrid specified in the Part. Will
each of them be used at any elevation of the wall project or should elaborate
more specifically based on the elevations/locations of the wall? The product
sheet from the manufacturer should be attached to the Specification.
c. According to drawing Sheet Nos. 47 & 48 of 52, the lengths of the primary
geogrid are varied at different stations and/or elevations of the wall at the
same location. This Part should provide the length(s) by station in a tabular
format.
d. The specified minimum “Junction Strength” and testing method (ASTM
D7737?) should be provided for both primary and secondary geosynthetic
reinforcements.
vi. (Part 2.2) The on-site cohesive soil material is selected to use as reinforced fill.
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a. Reinforced fill material should be tested for the following electrochemical
properties:
- pH values and
- Organic content.
b. (Part 2.2A) Reinforced fill material should be specified/tested for the design
parameters (unit weight, cohesion, and friction angle) in Section 5 of J
Geotechnical Data of the Permit Application. The test results for each
parameter shall not less than the values concluded from the MSE wall design.
c. Reinforced fill material should be tested for the following engineering
properties:
- Unified Soil Classification System & supported by field-manual method,
- Grain size distribution/gradation limits (including the maximum #200
passing amount), and
- Atterberg limits & plasticity index.
This Part should specify the passing criteria, testing methods, and frequencies for
the above-referenced test items.
vii. (Part 2.2D) Per specification requirement in Part 3.1F, please add the moisture
content test(s) to this Part.
viii. (Part 2.4)
a. Attach the product sheet of North American Green C350 and installation
specification to this Specification.
b. Add the specification (Per ASTM D 186) of welded wire form (WWF) to this
Part.
ix. (Part 2.5) ASTM D 4873 shall be followed for identification, storage and handling
all geosynthetic material – rolls and samples. Additionally, add the following
requirement to this Part- At the time of installation, the Owner or his designee
shall reject the geosynthetic reinforcement if it has defects, tears, punctures,
flaws, deterioration, or damage incurred during transportation, or storage.
x. (Part 2.6)
a. The long-term, allowable strength, Tallow, to be used in design considering all
the phenomena which could influence the geogrid during its service lifetime –
Reduction Factor for Creep (RFCR), Reduction Factor for Installation Damage
(RFID), Reduction Factor for Durability/Aging (RFD).
- Specify the reduction factors concluded from the MSE wall design in K –
Calculation of the Permit Application.
- The geosynthetic reinforcement manufacturer should provide a certification
that the reduction factors which should meet the specified values in this Part.
b. Specify the pullout strength including pull out coefficients (F*, ) the
specified geosynthetic reinforcement which shall exceed the designed
parameters in K – Calculation of the Permit Application.
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xi. (Part 3) Please provide the specifications associated construction of a test strip or
a mock wall which shall be constructed by the same material specified in Part 2
and equipment/machinery and construction procedures specified in Part 3. The
requested specifications for construction a test strip or mock wall and testing on
retrieved primary geosynthetic reinforcement should be prepared according to
ASTM D5818-“Standard Practice for Exposure and Retrieval of Samples to
Evaluate Installation Damage of Geosynthetics” and WSDOT Standard Practice
T925. The test results should be used for adjusting the default reduction factors in
the long-term strength of geosynthetic reinforcements in K – Calculation of the
Permit Application and the design service life of the MSE wall.
xii. (Part 3.1A) The drawings pertain lines and grade, both the existing and final
grades of the wall foundation are not available in the Permit Application.
Additionally, the extent of the topo survey zone afront wall should be extended to
area occupied by obstructions or environmental sensitivity zones, such as
drainage features, storage unit, infrastructures, utility lines, LFG & LCR piping
etc. Please provide the request drawings.
xiii. (Part 3.1B) Please specify which project specification (Section & Part) shall be
followed for compacting backfill.
xiv. (Part 3.1C)
a. Specify the minimum passing of the specified proof-roll machinery.
b. Specify the design parameters (Section & Part). The specified paragraph 7.0
is not available in the Specification.
xv. (Part 3.1D)
a. What is the compacted thickness out of the 10-inch loose fill?
b. The thickness of the loose fill shall be adjusted based on the testing results
from in-pace density to meet the compaction effort specified in Part 3.1F.
c. This Part should specify the procedures to spread fill into WWF area. What
should cares be taken to avoid any activities resulting in the deformation,
distortion, or bulge of the facing unit?
xvi. (Part 3.2) After the foundation is completely constructed, this Part should provide
the general sequence construction of the first and following layers of the MSE
wall system as shown on the Typical Details – Sheets 48 of 52 through 52 of 52.
a. When the turf reinforcement mat/blanket the secondary and primary
geosynthetic reinforcements will be deployed?
b. When the wield wire form/facing unit will be installed?
c. When the vegetative soil with seeds (?) and reinforced soil will be
backfilled/compacted?
xvii. (Part 3.2B) The length of the geosynthetic reinforcement that is varied by
elevations and by survey stations along the wall alignment according to design (in
K – Calculation of the Permit Application) and notes on the drawing. Please
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provide the designed and specified geosynthetic reinforcement length in the
Permit Application.
xviii. (Part 3.2H & I) Show the requirement on the drawing/sheet.
xix. (Part 3.2J) Show the connection/splice details on drawing/sheet.
xx. (Part 3.2L) Because the backside of the MSE wall will intimately connect a to-be-
constructed earthen berm.
a. Please discuss the construction sequences of the wall and the berm. Which
one is going to be constructed first? How to coordinate the construction
project? If the earthen berm is completely constructed before wall, how the
surface water on top of the fill later can be drained toward the backside of the
wall?
b. The Typical MSE Wall Section on drawing Sheet 00C-18 shows a subdrain
which will be constructed on the wall foundation area? How the
infiltrating/percolating surface water in the wall system will be leading to this
subdrain? The Specification shall include the subdrain construction – material
and construction methods and sequences.
c. Show the typical details of the specified temporary drainage measures on the
drawing/sheet.
xxi. (Part 3.3B)
a. In addition to the testing frequency specified in this Part, the testing of
compaction efforts & moisture contents on in-placed compacted fill should
specifically conducted at area within 3-feet from facing unit. The testing
frequency may be one in-place test per X linear feet per 18-inch-thick layer
along the wall alignment.
b. The moisture content of the in-placed compacted fill shall be tested, and test
results shall meet the specified criteria in Part 3.1F.
xxii. The Specification regards the Phase A wall end termination and connection
between the wall Phases A & B.
xxiii. The Specification should provide requirements for as-built survey and tolerance
of the constructed MSE wall. The scopes of the as-built survey should include,
but not limited to, the Phase A wall layout/alignment; the lengths of geosynthetic
reinforcements by stations and elevations; typical cross-section of the wall
including the corners/turns of the walls; elevation view of the wall including the
elevations of the top of the finished grades, grades of each finished fill layer with
setback, the foundation grades, the existing grades; the locations of stormwater
drop inlets & drainage outlet locations and invert elevations; locations / top
elevations of all utility lines, leachate force-main; the monitoring points (such as
slope indicators, settlement plats etc., if any); and the haul road location and
grade/thickness. The as-built survey must be conducted, signed and sealed by a
North Carolina licensed surveyor, not by the Professional Engineer.
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86. (Section 33 47 14 – HDPE)
i. (Part 1.2C.c.) The specification Section 01 45 29 is not available in the Technical
Specification.
ii. (Part 1.3A.2.a.) The specified 1.2B is likely a typo. Part 1.2C is the specification
for the installer’s qualification.
iii. (Part 1.3A.3) The specified Specification Section 01 45 00 is not available in the
Technical Specification.
iv. (Part 1.3A.4) The specified Specification Section 01 31 19 is not available in the
Technical Specification.
v. (Part 1.3A.1.d) Please specify the testing method and passing criterium of each
CQA test or provide the references to Part 2.2 MQA testing specification.
vi. (Part 2.2) The Table in this Part is out-of-date. Please use the latest version (Rev.
15 dated September 09, 2019) of Table 2(a) of GRI- GM13 (Textured HDPE).
vii. (Part 3.1A.4.c)
a. The frequency of confirming the specified minimum compaction effort by
testing in-place density should be specified.
b. Should the trench backfill material have the maximum grain size less than
0.75 inches as specified in Part 3.1A2.c?
viii. (Part 3.1B.4) Specify the deployment requirements for this project:
a. Specification of requirements of not to working in the wet weather and windy
condition.
b. Seam orientation to the top of the slope.
c. Panels overlap manner (end to end by shingle approaches) and the overlap
width in respect with the panel orientations (end-to-end or side-by-side
seams).
d. Seam orientation shall be maintained for distance of 10 feet from the toe of
slope.
e. Horizontal seams shall not be allowed on the side slopes unless approved by
the Engineer. The approval must be documented in the certified CQA Report.
f. Unroll only the sections of panels which are to be seamed together in that day
or which are coordinating with the extent of the installed GCL so that the
GCL will not be exposed overnight or to adverse weather condition.
ix. (Part 3.1B.5) The vacuum box (ASTM D5641) shall only be used for single
wedge seam or extrusion weld seam and air channel pressure test shall be applied
to all double-wedge fusion weld seams. Unique seam condition may be exempted
from the rigid specification but must be approved by the Engineer and
documented in the certified CQA report.
x. (Part 3.1C)
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a. Is this Part compatible with latest version of GRI-GM19 as the specification
of destructive seam testing?
b. The peel strength criteria shall apply to both the top and bottom welds of the
double-wedge fusion welds.
c. The minimum values of peel strength for a single wedge seam or extrusion
weld seam and double-wedge fusion weld seams are different from those in
GRI-GM19.

87. (Section 33 47 16 – LLDPE)
i. (Part 1.2C.c.) The specification Section 01 45 29 is not available in the Technical
Specification.
ii. (Part 1.3A.1.d) Please specify the testing method and passing criterium of each
CQA test or provide the references to Part 2.2 MQA testing specification.
iii. (Part 2.2) The Table in this Part is out-of-date. Please use the latest version (Rev.
13 dated September 09, 2019) of Table 2(a) of GRI- GM17 (Textured LLDPE).
iv. (Part 3.1A.4.c)
a. The frequency of confirming the specified minimum compaction effort by
testing in-place density should be specified.
b. Should the trench backfill material have the maximum grain size less than
0.75 inches as specified in Part 3.1A2.c?
xi. (Part 3.1B.4) Specify the deployment requirements for this project:
a. Specification of requirements of not to working in the wet weather and windy
condition.
b. Seam orientation to the top of the slope.
c. Panels overlap manner (end to end by shingle approaches) and the overlap
width in respect with the panel orientations (end-to-end or side-by-side
seams).
d. Seam orientation shall be maintained for distance of 10 feet from the toe of
slope.
e. Horizontal seams shall not be allowed on the side slopes unless approved by
the Engineer. The approval must be documented in the certified CQA Report.
v. (Part 3.1B.5) The vacuum box (ASTM D5641) shall only be used for single
wedge seam or extrusion weld seam and air channel pressure test shall be applied
to all double-wedge fusion weld seams. Unique seam condition may be exempted
from the rigid specification but must be approved by the Engineer and
documented in the certified CQA report.
xii. (Part 3.1C)
a. Is this Part compatible with latest version of GRI-GM19 as the specification
of destructive seam testing?
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b. The peel strength criteria shall apply to both the top and bottom welds of the
double-wedge fusion welds.
c. The minimum values of peel strength for a single wedge seam or extrusion
weld seam and double-wedge fusion weld seams are different from those in
GRI-GM19.

88. (Section 40 05 00 – Pipe And Pipe Fittings: Basic Requirements)
i. (Part 1.2A) This Part should list all testing methods specified in this Section.
ii. (Part 1.4B.) The grade or slope of piping (LFG condensate piping & LCR force-
main) are not specified in any drawings of the Permit Application.
iii. (Part 3.6) This Part shall specify the static hydraulic pressure test on the leachate
force main.

89. (Section 40 05 33 – HDPE Piping)
i. (Part 3.3A.) This Part specify the pipe trench requirements in accordance with
ASTM methods which are not included in the Section 31 23 33. Please explain
why there are two separate sets of specifications for piping trench, installation &
backfill.
ii. (Part 3.6B.3)
a. Please define landfill piping.
b. Please detail the pressure piping test procedures and referring testing method.

J- Geotechnical Data
90. (Section 4.2) Has the historical data from on-site permanently groundwater wells been
used for the determination of groundwater table underneath the wall?

91. (Section 5)
i. Please elaborate what is (are) the reason(s) to select these five cross sections for
evaluation?
a. Are the selected sections representative to specific soil stratifications or
engineering properties within the stations?
b. Why not more stations? The stations 6+00, 26+00, 29+00 in Appendix A are
removed from selected sections.
ii. Have the determined design parameters stated in this Section been incorporated
into the MSE wall Specification Section 31 38 40. What about other engineering
parameters of the selected reinforced fill material such as index properties
(Atterburg Limits), density, the maximum dry density, and optimum water
content.
iii. (Table 5-1 through Table 5-6)
a. Add the soil depths to each layer under the station.
b. Append the referenced literatures, chart/table for “Justification.”
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92. (Section 6) Prior to conducting the described foundation designs and stability analyses, a
sub-section to define the external loading both static and dynamic loads, including but not
limited to, wall material (self-weight of wall), lateral pressures from MSW & earthen
berm/inboard wall, equipment operations during constructions and landfill operations,
traffic load, potential hydraulic pore water pressure behind the wall or inside the wall
unit, seismic loading, etc.

93. (Sections 6 & 7)
i. Will the wall base be constructed on the existing grade? If not, what is
embedment depth per designed station.
ii. What are dimensions of the wall bases.
iii. According to Section 6, the wall external stability analysis and global stability
analysis conclude the soil located beneath the proposed wall, specifically along
the Station 10+00 through 47+00 – approximately 3,700 liner-feet-long can not
support the proposed wall with the targeted factor of safety of 2 until,
approximately 9 months (Section 6.3) or from 85 days to 260 days (Table 6-1)
after completion of the wall, when the soil is settled / consolidated (pore water
pressure dissipated from the soft soil layer) by the static loads from wall material
and gained strength.
a. Would the conclusions made in Section 6 imply that the wall may not be safe
to be use as it is designed for upon completion?
b. Should the Section 7 recommend any techniques to improve on-site soil
strength prior to constructing the proposed wall or the staged construction
approaches plus the pore water pressure monitoring as mentioned in the
Section 7 to deal with the issue?
94. (Section 7)
i. Table 7-1 shows the minimum reinforcement length to wall height ratio for each
of the station range.
a. Is the determined ratio uniformly applicable to entire height of the MSE wall
within the station range?
b. According to the MSE wall and Reinforced Soil Slope design manuals, the
ration of uniform reinforcement length to wall height is about 0.6 to 0.7, and
the recommended ratios in Table 7-1 range from 1 to 2.13. Why are the
differences so significant? Please explain.
ii. The recommendations for monitoring pore water pressure of soil layer underneath
the MSE wall are too vague. Regarding piezometer from the geotechnical
engineering prospect/application (do not be confused by a monitoring/observation
well which may be interchangeable by hydrogeology), it is used to monitoring
water table/pore pressure at a specific soil layer. Therefore, which soil layer that
will required to follow the recommendation stated in this Section. The
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instrumentation / observation plan should be a portion of Section 14 of the
Operations Plan.

95. (Appendix A)
i. Provide definition of the following abbreviations shown in the boring logs:
a. SS-1. Does SS mean split spoon sample?
b. ST-1. Does ST mean Shelby Tube sample?
c. FIAD. What does this mean?
ii. xxx
96.
97. (Appendix A. The drawing – Boring Profile)
i. Add note fields to explain the legends (soil types) and number inside the circle
(SPT blow counts), groundwater tables (during the drilling, 24-hour after drilling
completion, or the seasonal height water table according to data from on-site
permanently groundwater wells), etc.
ii. The drawing – Boring Profile should be incorporated into a new drawing set
combining, at a minimum, the following information. This new set of drawing
should be included in Attachment L.
a. The final grades of the MSE wall foundation which including the surface
drainage network (drain surface water away from wall foundation) & wall
foundation drainage/subsurface drainage network - integrating backwall
drainage system and surface water (perimeter drain)/stormwater drainage from
closed landfill cover system.
b. Elevation view of the MSE wall above the final grades along the wall
alignments. The following data should be summarized in tabulate format:
A. Geosynthetic reinforcement – material, type, length, vertical space,
engineering parameters – strengths and reduction factors.
B. Reinforce fill – material, engineering parameters as specified in the
Specification Section 31 38 40.
c. All details in Attachment L that are related to this MSE wall project shall be
referenced accordingly.

98. (Appendix D)
i. How to determine the “equivalent” design perimeters of the foundation soil?
Please explain and show calculations with a typical example and references.
ii. Why does the lateral pressure exerting on MSE wall come from retained soil berm
alone? What about the massive trashes behind the wall inside the landfill unit?
iii. Some wall segments have two design scenarios such as Station 22+00 and Station
22+00 waiting period. The Sections 6 or 7 should provide the difference of the
design methods and define “waiting period.”

K – Calculations (note of conclusions)
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99. Appendix A- Final Cover Veneer Stability
i. Why is the 6-hour, not a 24-hour, designed precipitation selected for the design
calculation?
ii. Have the determined values been incorporated into the Attachment I - Technical
Specifications:
a. Transmissivity, thickness and interface angle for geocomposite.
b. Density, soil friction angle, and hydraulic conductivity for the vegetative soil
cover layer.

100. Operational Cover Veneer Stability
i. (Given, item 7) The landfill base protective soil cover layer will not be covered by
grass or vegetation, but likely covered by a plastic rain cover; therefore, the
selected runoff curve number is underestimated.
ii. Have the determined values been incorporated into the Attachment I - Technical
Specifications:
c. Transmissivity, thickness and interface angle for geocomposite.
d. Density, soil friction angle, and hydraulic conductivity for the vegetative soil
cover layer.

101. Anchor Trench
i. This anchor trench design for landfill final cover system is not included.
ii. The details of the anchor trench should be included in the drawings in Appendix L
of the Permit application.

102. Earthwork and Site Life
i. The amount of soil required for the entire site development is required to be
estimated; therefore, the soil amount for future Phase B MSE wall area including
Phase 3 lateral expansion should be estimated.
ii. The soil volume from the existing and future borrow areas inside the landfill
facility should be estimated; then if the soil deficiency or adequacy can be
evaluated.

103. Tensar MSE Structure Calculations - The entire calculations are not acceptable because
they fail to comply with requirements stated in Rule 15A NCAC 13B. 1620(a).
i. In Project Summary, Sheet 2 of the shop drawing including design criteria and
construction requirements is not available in the Permit Application.
ii. All design parameters are not completely incorporated into the Technical
Specifications and the CQA Plan.
iii. The total wall height and design height (DH?) are never defined.
iv. The geosynthetic reinforcement (Geogrid) with different strength tensile strengths
and interface friction angles are applicable at different locations/elevations based
on the designs, but the elevation ranges are not defined.
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v. The theories and references of the wall design are not available. A typical
example of the design must be provided in the Permit Application as a tool for
understand the inputs and outputs of the computer design software used for this
project.
vi. The wall design does Not include the two-tier wall as shown on Detail 2 of Sheet
00C-18 & Sheet 48 of 52.
L Drawings
104. (Sheet 00G-03) Please confirm the permit limits of the lined landfill – 88 acres in this
Permit Application vs. 90 acres in the approved permit documents & other drawings –
Sheet 00G-04, -06.

105. (Sheet 00G-06) Has the perimeter gas monitoring well MM-13 been installed? If so, the
legend shall be revised, and the Note 4 is not required.

106. (Sheet 00C-01) For O&M requirements, the drop inlet may be required identifications
with unique nomenclature (just like those for monitoring wells, sediment basins).

107. (Sheets 00C-03 & 04) The detailed and blow-up final baseliner system of the NEW
EXPANDED LANDFILL SUB-CELL are required– top grades of the finished
subgrade, top grades of compacted soil liner layer, the geosynthetic liner panel layout, top
finished grades of protective cover layer, etc.

108. (Sheets 00C-18 & -20)
i. Show the details of utility lines & LCR force-main, LFG piping trenches
according to Technical Specification.
ii. The haul road is made of porous aggregates on the top of the MSE wall. Is there
any measure to stop surface water percolating downward to the reinforced soil
zone? If not, propose how you will prevent a local perched water or soft wet
zone that may develop inside the wall body?

109. (Sheets 00C-22) How are pre-cast concrete manholes designed to resist down-drag
forces due to waste and soil settlements? Should the manhole leak, the stormwater will
likely erode or wash away the surrounding earthen material. Propose how you will
prevent this condition?

iii. (Sheet 47 of 52) The typical wall section is misleading. According to MSE wall
calculations, the reinforcement has varied type and length at different location/zone and
different elevations.

Ms. Jan McHargue, PE
##, 2020
FID XXX
Page 40 of 40

If you have any questions you may contact me at 919-707-8251 [e-mail]. If you
are interested in participating a meeting to discuss the above-referenced comments, please
inform the SWS of the times and dates; so we can make the necessary arrangement.

Sincerely,

Ming-Tai Chao, P.E.
Environmental Engineer
Division of Waste Management, NCDEQ

cc:
Gordon Dively, P.E., City/County Utilities Michael Plummer, P.E., HDR
Thomas M. Yanoschak, P.E., HDR Sherri Stanley, Permitting Branch Supervisor
Susan Heim, DWM Deb Aja, DWM
Jackelyn Drummond, DWM Central Files