1812_DukeMarhall_2023Q4_GWCR_FID1827384_20240201

(� DUKE
ENERGY
February 1, 2024
North Carolina Department of Environmental Quality
Division of Waste Management
Solid Waste Section
2090 U.S. Highway 70
Swannanoa, NC 28778
Attn: Ms. Sarah Moutos (submitted electronically)
Re: Groundwater Condition Quarterly Report — October 2023 through December 2023
Industrial Landfill No.1
Permit No.: 1812-INDUS-2008
Marshall Steam Station
Terrell, North Carolina 28682
Dear Ms. Moutos:
525 S. Tryon St.
Charlotte NC, 28202
In accordance with the NCDEQ DWM September 17, 2021, Phase 2 Permit Modification Approval letter (FID
1609547), Duke Energy is providing the quarterly report describing groundwater conditions in the area of the
Marshall Steam Station Industrial Landfill No.1 (ILF, 1812-INDUS-2008) Phases 2, 3, and 4. The report is for
the quarterly period of October 2023 through December 2023 (Q4 2023).
The quarterly report includes an analysis of groundwater levels and underdrain pump flowrates within Phases
2, 3 and 4, with an updated water level map, hydrographs, pump flowrate plot, and well construction and water
level data tables. An evaluation of groundwater levels and pump flowrates compared to model predictions is
included. Groundwater transducer data, groundwater model trend data, and underdrain pumping data are
provided in an excel file format as the report Appendices.
Groundwater conditions in the vicinity of Marshall Steam Station's Industrial Landfill No.1 continue to be
monitored and evaluated. The next quarterly report (Q1 2024) will be submitted by May 1, 2024.
If you need additional information regarding this submittal do not hesitate to email or call me at
Ashley.Healy(@duke-energy.com or [phone].
Respectfully submitted,
j4VAi
Ashley Healy, P.G.
Environmental Services
Attachments: Industrial Landfill No.1 (1812-INDUS-2008) Groundwater Conditions Quarterly Report — October
2023 through December 2023 (SynTerra; February 2024)
Appendices in excel format:
1) Appendix A Water Level Monitoring Data Files
2) Appendix B Groundwater Model Predicted Trend File
3) Appendix C Underdrain Pumping Data File
4) Appendix D Mann -Kendall Results
www.duke-energy.com Page 1 of 2

cc (via e-mail): Claire Osborn, NCDEQ
Elizabeth Werner, NCDEQ
Sherri Stanley, NCDEQ
Ed Mussler, NCDEQ
Scott Saunders, Duke Energy
Dan Zakary, Duke Energy
Chris Varner, Duke Energy
Tyler Hardin, Duke Energy
Ed Sullivan, Duke Energy
Thomas Colton, SynTerra
Craig Eady, SynTerra
www.duke-energy.com Page 2 of 2

L1
synTerra
Science & Engineering Consultants
synterracorp.com
GROUNDWATER CONDITIONS QUARTERLY REPORT -
OCTOBER 2023 TO DECEMBER 2023
INDUSTRIAL LANDFILL NO. 1
(1812-INDUS-2008)
FOR
MARSHALL STEAM STATION
8320 EAST CAROLINA HIGHWAY 150
TERRELL, NC 28682
JANUARY 31, 2024
PREPARED FOR
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DUKE ENERGY CAROLINAS, LLC
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Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
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PAGE
1.0 INTRODUCTION........................................................................................................1-1
1.1 Objectives and Purpose...............................................................................................1-1
1.2 Key Findings.................................................................................................................1-1
2.0 QUARTERLY MONITORING RESULTS......................................................................... 2-1
2.1 Current Groundwater Conditions................................................................................2-1
2.2 Groundwater Trends.................................................................................................... 2-1
2.2.1 Water -Level Hydrographs and Model Trends ....................................................... 2-2
2.3 Underdrain Pump Performance...................................................................................2-3
3.0 QUARTERLY WATER -LEVEL REDUCTION ACTIVITIES ................................................... 3-1
4.0 REFERENCES.............................................................................................................4-1
January 2024 Page i
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
LIST OF FIGURES
Figure 1
Monitoring Location Map
Figure 2
Area of Focus Water -Level Map — Upper Flow Zone (January 2024)
Figure 3A
Upgradient of Phase 2 Expansion (MW-4/D and ILF-2S/D)
Figure 313
Upgradient of Phase 2 Expansion (GWA-4S/D and CLF21-10)
Figure 3C
Within Phase 2 Expansion (CLF-UD and CLF21-11)
Figure 3D
Within Phase 2 Expansion (CLF21-12 and CLF21-13R)
Figure 3E
Within Phase 2 Expansion (CLF21-14R and CLF21-15)
Figure 3F
Within Future Phase 3 Expansion (CLF-301 and CLF22-305)
Figure 3G
Downgradient of the Phase 2 Expansion (CLF-401 and CLF-402)
Figure 3H
Downgradient of the Phase 2 Expansion (CLF22-306 and CLF22-307)
Figure 31
Downgradient of the Phase 2 Expansion (CLF23-405 and CLF23-406)
Figure 3.1
Downgradient of the Phase 2 Expansion (CLF23-407 and CLF23-408)
Figure 4
Cell 5 (Underdrain) Pumping Flow Rate Vs. Simulated Flow Rate
LIST OF TABLES
Table 1 Groundwater Monitoring Network Well Information and Water Levels
LIST OF APPENDICES
Appendix A Water -Level Monitoring Data Files
Appendix B Groundwater Model Predicted Trend File
Appendix C Underdrain Pumping Data Files
Appendix D Mann -Kendall Data
January 2024 Page H
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
IIII &10]9_T411d01L1YJ►TA&I
CCR
coal combustion residuals
Duke Energy
Duke Energy Carolinas, LLC
DWM
Division of Waste Management
Future Phases
ILF Phases 3, 4, and 5 expansion
gpm
gallons per minute
ILF
Industrial Landfill 1812-INDUS-2008
NCDEQ
North Carolina Department of Environmental Quality
NPDES
National Pollutant Discharge Elimination System
reporting period
fourth quarter 2023 (October 2023 to December 2023)
Site
Marshall Steam Station
January 2024 Page Hi
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
1.0 INTRODUCTION
1.1 Objectives and Purpose
SynTerra prepared this Groundwater Conditions Quarterly Report on behalf of Duke Energy
Carolinas, LLC (Duke Energy) to document the water -level monitoring data and underdrain
pumping records in the vicinity of the Industrial Landfill No.1 (ILF) (Permit No. 1812-INDUS-
2008) at the Marshall Steam Station (Site). This report is prepared in response to condition #3
in the North Carolina Department of Environmental Quality (NCDEQ) Division of Waste
Management (DWM) September 17, 2021, Phase 2 Permit Modification Approval letter (FID
1609547).
Data collected during the fourth quarter of 2023 (October 2023 to December 2023) reporting
period were used to evaluate groundwater conditions for the ILF Phase 2 expansion (includes
Cell 5 and Cell 6) and ILF Future Phases 3, 4, and 5 expansion (Future Phases). Specifically, this
report evaluates the groundwater levels, underdrain pumping flow rates, and efforts to
expedite reducing and maintaining groundwater levels near the ILF during the reporting period.
1.2 Key Findings
Key findings of the evaluation conducted during this reporting period include:
• Water levels are monitored in at 22 piezometers and monitoring wells and the ILF
underdrain. During the reporting period, two piezometers (CLF-301 and CLF22-305)
were abandoned; reducing the current number of monitoring locations from 22 to 20.
Groundwater levels in the area are generally stable or decreasing.
• During the reporting period, water levels continue to decrease at 18 out of 22 locations;
other locations are generally stable, with the exception of GWA-4D which exhibits an
increasing trend for the reporting period. Locations where water levels are greater than
model predictions can be attributed to a slower basin excavation rate than assumed in
the model.
• The Cell 5 underdrain pump has been operational for 28 months with an average
pumping rate of 8 gallons per minute (gpm). During the reporting period, the pumping
rate continued to decrease, (10.4 gpm average in October through 6.9 gpm average in
December). While the flow rates vary, the overall trends reasonably match the model
predictions. The model predicted the underdrain to become dry after approximately 19
months of operation; however, the slower basin excavation rate has extended the
period needed to operate the underdrain.
January 2024 Page 1-1
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
2.0 QUARTERLY MONITORING RESULTS
The established network of temporary and long-term piezometers and groundwater wells for
monitoring groundwater conditions in the ILF Phase 2 expansion area is shown on Figure 1.
Piezometer and groundwater well construction information (including water level and
groundwater elevations) for the monitoring network is included in Table 1.
2.1 Current Groundwater Conditions
Area of focus water levels were collected on January 5, 2024, for the upper (shallow) flow zone
and were used to generate a groundwater level map (Figure 2). Site -wide water level sweeps
occur semiannually during the second and fourth quarter. Observed groundwater levels during
this reporting period indicate:
• Groundwater is generally flowing north to south through the ILF area (Figure 2).
• Groundwater levels in wells within and near the ILF have decreased, relative to
groundwater levels from Quarter 3, 2023, except CLF21-13R.
• Underdrain operations in Cell 5 have maintained a cone of groundwater depression
around the Cell 5 blanket underdrain sump (CLF-UD, Figure 2).
2.2 Groundwater Trends
A series of groundwater monitoring wells, piezometers, and the Cell 5 underdrain (CLF-UD)
pump transducers are used to monitor water -level trends from as early as July 2021 through
December 2023 (Figures 3A through 3J). The following are key observations of overall trend
data:
• CLF23-405, CLF22-307, and CLF22-306 were unable to be accessed for data collection
due to wet conditions resulting from precipitation. Several download attempts were
made to download the data in January 2024. Data for these locations are presented
through the end of November 2023; remaining data are expected to be presented in the
Q2 report.
Groundwater level data collected from July 2021 (when close monitoring started)
through December 2023 were evaluated using Mann -Kendall analysis to determine
water -level trends (Appendix D). Statistically significant decreasing overall trends were
observed in 20 of 22 locations. A overall stable trend was observed at CLF21-12 and
CLF21-14/R, however both of these locations exhibited decreasing trends during the
reporting period.
• Generally, decreasing or stable trends were observed in locations downgradient of the
Future Phases area during the reporting period (October 2023 through December 2023)
and decreasing trends for the overall period (July 2021 through December 2023).
January 2024 Page 2-1
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
2.2.1 Water -Level Hydrographs and Model Trends
Pressure transducers are used to record high -resolution groundwater elevation data for
evaluation of groundwater conditions resulting from dewatering and excavation.
Transducer data in Excel spreadsheets are included in Appendix A. Manual water -level
measurements and transducer records were used to generate hydrographs. Predicted
groundwater level trends from the transient groundwater models are included in the
hydrographs (Figures 3A through 3L). Appendix B contains Excel spreadsheets with the
predicted transient groundwater level trends exported from the models.
Upgradient of the Phase 2 Expansion:
• MW-4/1) are located east of the ILF Phase 2 expansion (Figure 1). The shallow
and deep flow zone water levels at those locations have overall decreasing
trends. MW-4 and MW-41) show significantly decreasing trends over the
reporting period (Figure 3A).
ILF-2S/D are located north of the ILF (Figure 1). The shallow and deep flow zones
water levels have overall decreasing trends and show decreasing (ILF-21)) and
stable (ILF-2S) trends during the reporting period (Figure 3A).
Monitoring locations GWA-4S/D and CLF21-10 are west of the ILF Phase 2
expansion (Figure 1). The shallow flow zone water levels at those locations have
overall decreasing trends and showed decreasing trends during the reporting
period. Deep flow zone water levels in GWA-4D have an overall decreasing trend
and an increasing trend during the reporting period, despite being generally
stable (Figure 313).
Within the Phase 2 Expansion:
• A transducer, identified as CLF-UD (Figure 1), was installed to monitor the Cell 5
underdrain sump water level with the temporary pump operations while the
landfill cell was under construction. In October 2022, a permanent pump was
installed; the water level in the permanent pump is recorded manually every
week. The water levels within the sump demonstrate that the underdrain
continues to operate as intended, maintaining a steady water level controlled by
the pump settings (Figure 3C).
Perimeter of the Phase 2 Expansion:
• CLF21-11, CLF21-12, and CLF21-13R are located west and south of Cell 5. Shallow
water levels at CLF21-11 show an decreasing trend since monitoring began as
well as during the reporting period. Water levels in CLF21-12 show a stable trend
overall since completion of the Cell 5 construction, however the water level
showed a decrease during the reporting period. CLF21-13R water levels are
overall decreasing but were stable during the reporting period (Figures 3C and
3D).
January 2024 Page 2-2
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
• Monitoring locations CLF21-14R and CLF21-15 are west of Cell 6 (Figure 1).
Water levels in CLF21-14R have an overall stable trend since ash excavation was
completed for Cell 6, however the water levels are decreasing over the reporting
period. CLF21-15 has an decreasing trend since monitoring began as well as
during the reporting period(Figure 3E).
Within the Future Phase 3 Expansion:
Monitoring locations CLF-301 and CLF22-305 are within the Future Phase 3
expansion (Figure 1). Shallow water levels at CLF-301 and CLF22-305 have an
decreasing trend since monitoring began as well as during the reporting period
(Figure 3F). Water levels in CLF22-305 dropped below the transducer but manual
measurements indicate that the water level decreased slightly during the
reporting period.
Downgradient of the Phase 2 Expansion (Future Phases Area):
Monitoring locations CLF-401 and CLF-402 are within Future Phases 4 and 5
expansion (Figure 1). Shallow water levels at CLF-401 and CLF-402 have an
overall decreasing trend and were decreasing during the reporting period
(Figures 3G). CLF-402 decreased during the reporting period until the water level
dropped below the transducer.
• Monitoring locations CLF22-306 and CLF22-307 are downgradient of the Future
Phase 3 expansion (Figure 1). Shallow water levels at CLF22-306 and CLF22-307
show decreasing water level trends overall and during the reporting period.
(Figures 3H). The transducer record at CLF22-306 and CLF22-307 do not include
most of December 2023 because they were inaccessible during January 2024 due
to wet site conditions.
• Monitoring locations CLF23-405, CLF23-406, CLF23-407, and CLF23-408 (Figure 31
and 3J) located in the Future Phases 3 and 4 have decreasing trends during the
reporting period and overall, except CLF23-407 which was stable during the
reporting period and shows an overall decreasing trend. The transducer record
at CLF23-405 does not include most of December 2023 because it was
inaccessible during January 2024 due to wet site conditions.
2.3 Underdrain Pump Performance
An underdrain pump is installed within the Cell 5 underdrain (CLF-UD) (Figure 1). The
underdrain pump removes groundwater from below the ILF Phase 2, Cell 5. The Cell 5
underdrain pump does not receive precipitation runoff; the underdrain is enclosed. Water
removed by the pump is discharged to the lower portion of the ash basin where it is ultimately
pumped through a water treatment system and discharged through an NPDES (National
Pollutant Discharge Elimination System) outfall. The Cell 5 underdrain pumping and model -
predicted dewatering rates are shown on Figure 4.
January 2024 Page 2-3
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
The Cell 5 underdrain pump has been operational for 28 months, at an average pumping rate
for the reporting period of 8 gpm. ILF Cell 5 pumping data, including the calculated monthly
total volume pumped and monthly average flow rate are included in Appendix C.
Pumping operations for the Cell 5 underdrain have removed approximately 1.1 million gallons
of water during the reporting period. The Cell 5 underdrain average flow rates for the reporting
period and each month are listed below.
• The Cell 5 underdrain pump had an average flow rate of 8 gpm overall during the
reporting period and monthly average flow rates of:
o 10.4 gpm during October 2023
o 7.7 gpm during November 2023
o 6.9 gpm during December 2023
January 2024 Page 2-4
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
3.0 QUARTERLY WATER -LEVEL REDUCTION ACTIVITIES
Efforts made during the reporting period by Duke Energy to safely expedite the reduction of
groundwater levels within the ILF Phase 2 expansion and the Future Phases include:
Phase 2, Cell 5
• Underdrain operations continued, with an average flow rate of approximately 8 gpm.
• Cell 5 operations continue.
Phase 2, Cell 6
• Cell 6 operations began on October 9, 2023.
Phase 3, Cell 7
• The ILF Phase 3 Permit to Construct Application was approved by NCDEQ on December
29, 2023. Construction is anticipated to start by Summer 2024.
Future Phases
• Excavation of coal combustion residuals (CCR) in the Future Phases continued during the
reporting period.
The installation of approximately 136 dewatering wells was completed during the prior
reporting period to support the construction of the Structural Fill (CC130031) northern
stability feature. The dewatering wells began and continued intermittent operations in
November 2023 through the remainder of 2023. The dewatering wells are phase 1 of a
larger scale dewatering system that is expected to temporarily influence the
groundwater elevations in the vicinity of ILF Future Phases nearest the stability feature
dewatering system. Note the dewatering system to support construction of the stability
feature was not included in the groundwater model simulations.
January 2024 Page 3-1
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
4.0 REFERENCES
SynTerra (2021). Technical Memorandum: Modeling Support for the ILF Phase 2 Permit to
Construct Modification, Marshall Steam Station. October 5, 2021.
January 2024 Page 4-1
Project: 00.0083.46.09

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
FIGURES
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3. ALL BOUNDARIES ARE APPROXIMATE.
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■ _ - 4. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS APPROVED
- BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2017 (SAW-2015-01412).
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1.1804 ,• WHEELER ENVIRONMENTAL AND INFRASTRUCTURE, INC. NATURAL RESOURCES
TECHNICAL REPORT (NRTR) DATED JUNE 2015.
-PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
6. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLYAND SHOULD
NOT BEUSED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED
BY TRANSASH.
7. AERIAL IMAGERY IS COMBINATION OF DUKE ENERGY PROPELLER AERIAL
PHOTOGRAPHYCOLLECTED ONJANUARY4 2024, AND MAXAR SATELLITE IMAGERY
AW OBTAINED FROM ESRI ONLINE COLLECTED ON AUGUST 23 2021.
8. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
RAPHICSC2 200 O00 400 FIGURE 1
NEE , MONITORING LOCATION MAP
DRAWN BY T KING DATE 04/28/2022 GROUNDWATER CONDITIONS QUARTERLY REPORT
REVISED BYT KING DATE_0TL/23/2024 OCTOBER 2023 THROUGH DECEMBER 2023
CHECKEDBY: T. COLTON DATE=01/23/2024 MARSHALL STEAM STATION
APPROVED BY T. COLTON DATE_ 01/23/2024
PROJECT MANAGER: T COLTON TERRELL, NORTH CAROLINA

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INFERRED WATER LEVEL CONTOUR (2.5' INTERVAL)
GROUNDWATER FLOW DIRECTION
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� NOTES:
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i 1. WATER LEVELS WERE COLLECTED ON 1/5/24, EXCEPTAT CLF22-305, CLF22-306,
AND CLF23-405 WHICH WERE INACCESSIBLE IN 1/5/24; 12/6/23 WATER LEVELS WERE
USED AT THESE LOCATIONS.
2. * -ABANDONED DURING THE REPORTING PERIOD.
3. ELEVATIONS ARE REFERENCED TO THE NORTH AMERICAN VERTICAL DATUM OF
1988 (NAVD 88).
4. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS
APPROVED BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2017
wo (SAW-2015-01412). WETLANDS AND STREAMS BOUNDARIES WERE OBTAINED FROM
o AMEC FOSTER WHEELER ENVIRONMENTAL AND INFRASTRUCTURE, INC. NATURAL
RESOURCES TECHNICAL REPORT (NRTR) DATED JUNE 2015.
5. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD
NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED
' BY TRANSASH.
6. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
•.;;t, 7. ALL BOUNDARIES ARE APPROXIMATE.
8. AERIAL IMAGERY IS A COMBINATION OF DUKE ENERGY PROPELLER AERIAL
PHOTOGRAPHY COLLECTED ON JANUARY 4, 2024, AND MAXAR SATELLITE IMAGERY
' OBTAINED FROM ESRI ONLINE, COLLECTED ON AUGUST 23, 2021.
9. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM RIPS 3200 (NAD83).
GRAPHIC SCALE
200 0 200 400 FIGURE 2
AREA OF FOCUS WATER -LEVEL MAP
(IN FEET) UPPER FLOW ZONE
DRAWNBY.T.KING DATE:05/12/2022 GROUNDWATER CONDITIONS QUARTERLY REPORT
REVISED BY: T. KING DATE: 02/01/2024
CHECKED BY: T CGLTGN DATE: 02/01/2024 OCTOBER 2023 THROUGH DECEMBER 2023
APPROVED BY: T. COLTON DATE: 02/01/2024 MARSHALL STEAM STATION
PROJECT MANAGER: T. CGLTGN TERRELL, NORTH CAROLINA
www-s nterracor .com
P:\O ARCGIS PRO PROJECTS\DUKE ENERGY\MARSHALL\2023\GW CONDITIONS OUARTERLY REPORT\GW CONDITIONS OUARTERLY REPORT 04 APRX

ILF-02S/D
MW-04/D
846
4
833
4
. �AmA.L
DO
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O
845
0
832
♦
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O
0
♦
3
00
I
3
a 844
O, O
z 831
z
♦ O O
I
c 843
c 830
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b o
2
2
_
o
W
to
a
I♦
M
W 842
W 829
o,
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OI O
fY
Gl
♦
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1
J
O ��♦�
1
841
♦O O
I
828
III
A
AL5
1
11,111,
840 0
827 0
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
Date
ILF-02S - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -1.3 feet.
MW-04 - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -4.5 feet.
ILF-02D - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -1.1 feet.
MW-04D - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -4.5 feet.
ILF-02S/D
M W-04/D
837
849
00
0
p 846
a 834
z
O
o
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--
o 0
0 ♦� I� ---------����
2 843
4
M 831.' Op
o
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W
W
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L 0 0 O 00
840
---------------
+� 828 O O 00
M
825
837
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 —North American Vertical
DUKE
r�
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3A
Future Phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
ENERGY..
REVISED BY: D.AVARD DATE:01/29/2024
UPGRADIENT OF PHASE 2 EXPANSION HYDROGRAPHS
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
,N
RpLIAS
CHECKED BY: T. COLTON DATE: 01/12/2024
INDUSTRIAL LANDFILL NO 1.1812-INDUS
� )
Cell 5 Blanket Underdrain construction completion (10/22/2021)
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data) in - inches
APPROVED BY:T. COLTON DATE:01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Deep Groundwater Flow Zone (Transducer Data) ♦ Manual Water Level Measurement
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
Bedrock Groundwater Flow Zone (Transducer Data) Daily Total Rainfall (inches)
synTem
TERRELL, NORTH CAROLINA
— — - Transient Groundwater Model Water Level Predicted Trend
www.synterracorp.com

GWA-04S/D
CLF21-10
852
4
843
4
851
842
00
•�
O
3
00
3
> 850
o
> 841
O
z
oo
z
c
�
c 849
2 "
c 840
2 :..
2
—
o
•M
°C
W 848
W 839
JKO
;&1;i
'@
a>
I
1
a>i
1
J
J
847
I
838
I
O
3
846 0
837 0
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
Date
GWA-04S - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -4.0 feet.
CLF21-10 -Total water level change from transducer installation on 08/10/2021 to 12/31/2023 is -0.9 feet.
GWA-04D - Total water level change from transducer installation on 07/30/2021 to 12/31/2023 is -4.5 feet.
GWA-04S/D
CLF21-10
855
844
00
0
852
—
> 842
o
a
O�
z
i .
U.
���
000 p O Oppu._
�
•O
o
O 000 O O
849
O O O
> 840
O
O O
a)
W
G>J
W
O O 0
�
O�
0
O OW
O
J
L 846
838
v
843
836
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 —North American Vertical
DUKE
r�
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3B
Future Phases 3 through 5 CCR excavation start (06/18/2021)
ENERGY..
REVISED BY: D.AVARD DATE:01/29/2024
UPGRADIENT OF PHASE 2 EXPANSION HYDROGRAPHS
Datum 1988
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
,N
RpLIAS
CHECKED BY: T. COLTON DATE: 01/12/2024
INDUSTRIAL LANDFILL NO 1.1812-INDUS
� )
Cell 5 Blanket Underdrain construction completion (10/22/2021)
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data) in - inches
APPROVED BY:T. COLTON DATE:01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Deep Groundwater Flow Zone (Transducer Data) ♦ Manual Water Level Measurement1101
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
Bedrock Groundwater Flow Zone (Transducer Data) Daily Total Rainfall (inches)
S1T�a
TERRELL, NORTH CAROLINA
F
— — - Transient Groundwater Model Water Level Predicted Trend
www.synterracorp.com

CLF-UD
CLF21-11
818
[.,SET.
00
00
0
a
z 814
+;
v
aj
J
L 810
M
<o 00 0 00 0 0 0
4
3
KA
1
c
4-
c
808 0
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
CLF-UD— Water level is stable during underdrain operations. Water levels spikes represent when pump was temporarily out of service.
CLF-UD
819
p 816
a
z
U-
a+
813
M
>
N
W
GJ
>
810
v
r
M
s�
807 T TTTTTT
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
i
832
830
828
826
824
822
3
1
820 0
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
CLF21-11- Total water level change from transducer installation on 08/09/2021 to 12/31/2023 is -4.8 feet.
CLF21-11
834
a 831
z
U.
o I OD I
828 d
a�
W
N O
N /<
L C
+� 825
ra
sE
822
6/1 /2021
\
\
\
O �
Op pip
� O
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
LEGEND
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 — North American Vertical
DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3C
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
ENERGY.
REVISED BY: D. AVARD
DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROI INAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE: 01/12/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
p
Daily Total Rainfall (inches)
�1��..i ery �
TERRELL ' NORTH CAROLINA
www.synterracorp.com

CLF21-12
CLF21-13/R
824
823
00
0
> 822
z
Lj-
c 821
0
41
M
a�
w 820
d
v
819 -
M
818
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
CLF21-12 - Total water level change from transducer installation on 08/09/2021 to 12/31/2023 is -3.0 feet.
1.3
1
00
0 8:
a
z
c
0 8
-W
M
>
GJ
W
GJ
>
GJ
J 8
L V
�1
i+
M
i
805 —4— - ' . ' T T T 1
6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
4
3
2
1
0
4-
M
GC
-
822
820
818
816
814
812
:r
CLF21-13 was abandoned and replaced on
November 4, 2021.
.J
4
3
c
2
1
810 0
6/1 /2021 11 /1 /2021 4/1 /2022 9/1 /2022 2/1 /2023 7/1 /2023 12/1 /2023
Date
CLF21-13R - Total water level change from transducer installation on 11/08/2021 to 12/31/2023 is -0.6 feet.
CLF21-13 - Total water level change from transducer installation on 08/09/2021 to 10/01/2021 is -0.2 feet.
CLF21-13/R
825
> 820
z o
U.
r-
0
815
a�
W
N
>
N
J
+� 810 Ij
(6
sE
0
.o o`o 0 0 00 0
0 0
0 0
i
805 —4— '.' I 1 1
6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
c
oc
LEGEND
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 — North American Vertical
DUKE
DRAWN BY: D.AVARD
DATE:07/21/2021
FIGURE 3D
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
ENERGY.
REVISED BY: D. AVARD
DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE: 01/12/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
p
Daily Total Rainfall (inches)
�1��..i ery �
TERRELL ' NORTH CAROLINA
www.synterracorp.com

CLF21-14/R
CLF21-15
823
4
827
4
822
826
O
00
Q
3
00 ZF
3
P�10�
a
821
a
825
a
z
o
z
♦
I
.-.
o ,-,
c
820
2
c
824
' O 2
o
o
O
♦
4-
o
o
p —
`-
>
c
>
c
u,
819
I
I- O ♦
x
uw
823
O
I
+
� �. II ♦ O �. II � � �
818
.� ;
1
822
817
0
821
0
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
6/1 /2021
10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
Date
CLF21-14R - Total water level change from transducer installation on 04/08/2022 to 12/31/2023 is +0.9
feet.
CLF21-15 - Total water level change from transducer installation on 08/13/2021 to 03/30/2023 is -3.5 feet. The CLF21-15 transducer was removed in April 2023.
• • • • • CLF21-14 - Total water level change from transducer installation on 08/13/2021 to 03/22/2022 is -3.3 feet.
The transducer was re -installed in July 2023. Total water level change from transducer installation on 07/31/2023 to 12/31/2023 is -0.9 feet.
CLF21-14/R
CLF21-15
830
828
0000
O
c
825
a
825
z
••
z
LL
o
0
0
00 0
o 0 0 0 o 0
820—♦�
O O
822
0 � 0� O O O
W
GJ
W
O
;
GJ
>
�
J
L
815
819
m
810
816
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 - North American Vertical
DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3E
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
ENERGY.
REVISED BY: D. AVARD
DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CAROI INAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON
DATE: 01/12/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
Shallow Groundwater Flow Zone (Transducer Data) in -inches
APPROVED BY: T. COLTON
DATE: 01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
-
Transient Model level Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
Groundwater water predicted trend
Daily Total Rainfall (inches)
sy1Tem
TERRELL NORTH CAROLINA
www.synterracorp.com
'

CLF-301
CLF-305
819 -
00 817
0
a
z
++
LL
c 815
0
41
M
a�
W
N
a>i 813 -
J
L
r
M
i�
811
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
CLF-301- Total water level change from transducer installation on 07/27/2021 to 12/06/2023 is -6.0 feet.
CLF-301—The transducer was removed 12/14/2023 and the well was abandoned in December 2023.
CLF-301
1.15Le]
0 816
a
z
41
41
813
M
>
GJ
W
W
>
GJ
810
v
r
M
807 -4-
6/1 /2021
12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet
Cell 5 Blanket Underdrain construction completion (10/22/2021) in - inches
Shallow Groundwater Flow Zone (Transducer Data)
Transient Groundwater Model water level predicted trend Manual Water Level Measurement
Daily Total Rainfall (inches)
4
3
'r1
1
0
C
812
CLF22-305 water level dropped below the
transducer as noted by manual water level
recordings starting 8/8/2023.
O
O �
O � �
O
♦e s
D
796
4
3
KA
1
0
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF22-305 - Total water level change from transducer installation on 08/10/2021 to 12/06/2023 is -8.3 feet.
The water level in CLF-305 dropped below the transducer elevation 08/01/2023. CLF-305 was abandoned in December 2023.
CLF-305
C
c
M
I-11CA
a 806
z
LL
0
799
a�
W
N
>
N
J
+� 792
m
sE
� a
785
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF22-305 was not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
CLF22-305 (after Transient Groundwater Model calibration)
DUKE DRAWN BY: D. AVARD DATE: 07/21/2021 FIGURE 3F
ENERGY. REVISED BY: D.AVARD DATE:01/29/2024 WITHIN PHASE 3 EXPANSION HYDROGRAPHS
CAROLINAS CHECKED BY: T. COLTON DATE:01/17/2024 INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
GROUNDWATER CONDITIONS QUARTERLY REPORT
1101 APPROVED BY: T. COLTON DATE:01/17/2024 OCTOBER 2023 THROUGH DECEMBER 2023
PROJECT MANAGER: T. COLTON MARSHALL STEAM STATION
synTem www.synterracorp.com TERRELL, NORTH CAROLINA

CLF-401
CLF-402
814
4
818
4
815
3
811
3
o
00
z
v 812
c
z o I
v 808
c
�
2 =-
c
2
0
—
>
M0
I
u, 809
I
—>
W 805
co
M
OI
+�
M 806
L
41
m 802
3
0
0i . . .
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
Date
Date
CLF-402 - Total water level change from transducer installation on 07/27/2021 to 12/31/2023 is -9.9 feet.
CLF 401-Total water level change from transducer installation on 07/27/2021 to 12/31/2023 is 9.7 feet.
The water level dropped below the transducer elevation 11/05/2023.
CLF-401
CLF-402
820
815
• O
op
O �
00 815
00
o
O
00
'o o �o 0o
z 810
•o o
>
z
o0o
O
° o00
U.
00
O
LL 810
..
\
0
0
a 805
M
ai
o
2 805
W
`
N
0
>
Qj
\
J
L
i
+�+ 800
r 800
f6
795
795
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical
DUKE
DRAWN BY: D. AVARD DATE:07/21/2021
FIGURE 3G
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.
REVISED BY: D. AVARD DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CAROI INAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON DATE: 01/17/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 01/17/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)
WnTem
TERRELL ' NORTH CAROLINA
www.synterracorp.com

CLF22-306
CLF22-307
807
807
4
4
804
804
°
00
3
00
3
o
�
z
z 801
+� 801
+;
cILLc
c
2
2=
o
♦
—
o
—
M
>
4—
M
> 798
W 798
I
W
GJ
a�i
1
G/
a�i
1
L
L 795
a1
a1
4-1
0 795
m
792
0
0
6/1 /2021 10/1
/2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 10/1 /2023
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
CLF22-306
- Total water level change from transducer installation on 08/13/2021 to 12/06/2023 is -7.4 feet.
CLF22-307 -Total water level change from transducer installation on 04/08/2022 to 12/06/2023 is -7.4 feet.
CLF22-306
CLF22-307
808
810
e
o
°
ap
`Q °
>
CLF22 307 was not
800
`
Z 800
` O O
used in the
°
Transient
Z
vGroundwater
Model calibration,
\
.0
water level
c
792
\
790
predictions were
M
T
_
�/
prepared
(Ij
\
W
following
W
v
installation of
>
CLF22-307 (after
J 784
`
+� 780
Transient
m
Groundwater
Model calibration)
776
770
6/1 /2021
12/1 /2021 6/1 /2022 /1 /2022 6/1 1 /2023 12//2023
6/1 /2021
12/1 1 /2021 6//2022 12/1 /2022 6/1 1 /2023 12//2023
Date
Date
CLF22-306 was
not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
The predicted increase of
modeled water levels is based upon the expected shutdown of the Cell 5 underdrain pumping operation. The slower basin
CLF22-306 (after
Transient Groundwater Model calibration)
excavation rate
has extended the period needed to operate the underdrain and will delay the shutdown of the Cell 5 underdrain.
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical
I f DUKE
DRAWN BY: D. AVARD DATE:07/21/2021
FIGURE 3H
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.
REVISED BY: D. AVARD DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CAROLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON DATE: 01/17/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 01/17/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)
syriTeria
TERRELL
' NORTH CAROLINA
www.synterracorp.com

CLF22-405
CLF23-406
807
4
810
4
807
00 804
3
0
3
o
�
a
a
z
z
+�
+; 804
-71
c
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c
c 801
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Gl
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1
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J
L
L
1
o
m 798
795
Ou
0
0
6/1/2021
12/1/2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1/2023
6/1/2021 12/1/2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1/2023
Date
Date
CLF23-405
- Total water level change from transducer installation on 03/01/2023 to 12/06/2023 is -9.1 feet.
CLF23-406 - Total water level change from transducer installation on 03/01/2023 to 12/31/2023 is -8.9 feet.
CLF22-405
CLF23-406
812
818
Do
p 804
p
a 810
a
z
z
o
r
O
....
�O
o
0 796
802
p
a�
O
w
\ 00
W
;
O
>
J
788
L
794
M
780
786
6/1/2021
12/1/2021 6/1/2022 /1/2022 6/1/2023 12/1/2023
6/1/2021
12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
Date
The predicted increase
of modeled water levels is based upon the expected shutdown of the Cell 5 underdrain pumping operation. The slower
The predicted increase of
modeled water levels is based upon the expected shutdown of the Cell 5 underdrain pumping operation.
The slower basin
basin excavation
rate has extended the period needed to operate the underdrain and will delay the shutdown of the Cell 5 underdrain.
excavation rate
has extended the period needed to operate the underdrain and will delay the shutdown of the Cell 5 underdrain.
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 - North American Vertical
r� DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 31
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.
REVISED BY: D. AVARD DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CARC]LINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON DATE: 01/12/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)
syriTeria
TERRELL
' NORTH CAROLINA
www.synterracorp.com

CLF23-407
CLF23-408
812
4
807
4
00 810
3
00 804
3
0
o
0
oe
a
o
a
z
z
c
�
c
c 808
2
801
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o
—
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Gl
a>, 806
1
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798
1
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J
I
L
O
L
241
ll"804
L
0
795 0
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
Date
CLF23-407 - Total
water level change from transducer installation on 03/01/2023 to 12/31/2023 is -4.7 feet.
CLF23-408 - Total water level change from transducer installation on 03/21/2023 to 12/31/2023 is -8.2 feet.
CLF23-407
CLF23-408
818
812
�
1
00
00
812
a 805
zz
z
o
°
o
0 806
> 798
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O
�
>
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W
>
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�
�
800
L
791
\
-
v
M
794
784
6/1/2021
12/1/2021 6/1/2022 /1/2022 6/1/2023 12/1/2023
6/1/2021
12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
Date
The predicted increase
of modeled water levels is based upon the expected shutdown of the Cell 5 underdrain pumping operation.
The slower
The predicted increase of
modeled water levels is based upon the expected shutdown of the Cell 5 underdrain pumping operation.
The slower basin
basin excavation
rate has extended the period needed to operate the underdrain and will delay the shutdown of the Cell
5 underdrain.
excavation rate
has extended the period needed to operate the underdrain and will delay the shutdown of the Cell 5 underdrain.
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 - North American Vertical
r� DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3J
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.
REVISED BY: D. AVARD DATE: 01/29/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CAROI INAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON DATE: 01/12/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 01/12/2024
OCTOBER 2023 THROUGH DECEMBER 2023
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
PROJECT MANAGER:T.COLTON
MARSHALL STEAM STATION
- Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)
syriTeria
TERRELL ' NORTH CAROLINA
www.synterracorp.com

0-
W
a�
co
oc
O
U-
c
.ru
N
C=
Ln
N
U
140
120
100
c
❑1
n
3
2
11
C
9/1/2021 3/1/2022 9/1/2022 3/1/2023 9/1/2023
Notes: Years of Operation
1. gpm = gallons per minute.
2. Flow data from the first day following a period of no flow were not plotted.
4 �' DUKE DRAWN BY: T. COLTON DATE: 10/13/2021 FIGURE 4
ENERGY REVISED BY: D. AVARD DATE: 01/10/2024
c CHECKED BY: T. COLTON DATE: 01/12/2024 CELL 5 (UNDERDRAIN) PUMPING FLOW RATE VS. SIMULATED FLOW RATE
APPROVED BY: T. COLTON DATE: 01/12/2024 GROUNDWATER CONDITIONS QUARTERLY REPORT
46� PROJECT MANAGER: T. COLTON OCTOBER 2023 THROUGH DECEMBER 2023
MARSHALL STEAM STATION
synTerra www.synterracorp.com TERRELL, NORTH CAROLINA

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
TABLE
L7
synTerra
Science & Engineering Consultants

TABLE 1
GROUNDWATER MONITORING NETWORK WELL INFORMATION AND WATER LEVELS
GROUNDWATER CONDITIONS QUARTERLY REPORT
OCTOBER 2023 THROUGH DECEMBER 2023
MARSHALL STEAM STATION
DUKE ENERGY CAROLINAS, LLC, TERRELL, NC
Well ID
Date Well/
Piezometer
Installed
Date
Transducer
Installed
Monitoring
Zone
Northing
(Ft-NAD 83)
Easting
(Ft-NAD 83)
Measuring
Point
TOC Elevation
(Ft-NAVD 88)
Ground
Surface
Elevation
(Ft-NAVD 88)
Total Well
Depth z'
(Ft-BGS)
Measured
Well Depth'
(Ft-TOC)
Screened
Interval 3
(Ft TOC)
Top of
Screen
Elevation
(Ft-NAVD 88)
Bottom
of Screen
Elevation
(Ft-NAVD 88)
Water Level
Measurement
(Ft-TOC)
11/07/2023
Groundwater
Elevation
(Ft-NAVD 88)
11/07/2023
Water Level
Measurement
(Ft-TOC)
12/06/2023
Groundwater
Elevation
(Ft-NAVD 88)
12/06/2023
Water Level
Measurement
(Ft-TOC)
01/05/2024
Groundwater
Elevation
(Ft-NAVD 88)
01/05/2024
CLF-301
5/21/2021
7/27/2021
Shallow
685838.40
1413513.30
847.46
844.46
62.00
65.00
52.00
62.00
795.46
785.46
35.85
811.61
36.15
811.31
Abandoned
CLF-401
5/17/2021
7/27/2021
Shallow
685783.50
1412779.50
832.44
830.44
39.00
41.00
29.00
39.00
803.44
793.44
26.47
805.97
27.03
805.41
27.04
805.40
CLF-402
5/21/2021
7/27/2021
Shallow
685598.80
1413217.80
818.41
816.41
50.00
52.00
40.00
50.00
778.41
768.41
16.32
802.09
16.93
801.48
17.24
801.17
CLF21-10
8/6/2021
8/6/2021
Shallow
687020.10
1412353.40
857.75
857.75
32.00
32.00
22.00
32.00
835.75
825.75
17.68
840.07
17.86
839.89
17.80
839.95
CLF21-11
8/5/2021
8/5/2021
Shallow
686572.30
1412572.20
850.17
850.08
40.00
41.64
31.64
41.64
818.53
808.53
24.11
826.06
24.64
825.53
24.60
825.57
CLF21-12
8/5/2021
8/5/2021
Shallow
686217.40
1412518.20
839.06
838.96
40.00
43.22
31.22
41.22
807.84
797.84
19.18
819.88
19.54
819.52
18.92
820.14
CLF21-13R
11/4/2021
11/8/2021
Shallow
686085.92
1412818.66
836.21
836.2
35.00
37.46
25.46
35.46
810.75
800.75
20.12
816.09
20.28
815.93
18.46
817.75
CLF21-14R
4/18/2022
4/18/2022
Shallow
686027.10
1414268.70
847.54
844.0
41.50
38.19
28.19
38.19
819.35
809.35
27.78
819.76
28.15
819.39
28.45
819.09
CLF21-15
8/10/2021
8/10/2021
Shallow
686307.70
1414410.00
864.37
864.37
55.00
55.00
45.00
55.00
819.37
809.37
40.75
823.62
40.91
823.46
41.10
823.27
CLF22-305
3/22/2022
4/8/2022
Shallow
685228.95
1413445.92
819.21
816.94
16.00
16.00
6.00
16.00
813.21
803.21
18.58
800.63
18.63
800.58
Abandoned
CLF22-306
3/22/2022
4/8/2022
Shallow
685033.00
1413752.34
816.36
813.57
25.00
25.00
15.001
25.00
801.36
791.36
20.36
796.00
2122
795.14
Inaccessible
CLF22-307
3/22/2022
4/8/2022
Shallow
684539.89
1413247.50
825.96
823.40
40.00
40.00
30.00
40.00
795.96
785.96
31.89
794.07
33.21
792.75
Inaccessible
CLF23-405
2/14/2022
3/1/2022
Shallow
684920.61
1413022.90
810.29
807.29
42.00
42.00
32.00
42.00
778.29
768.29
13.75
796.54
14.76
795.53
Inaccessible
CLF23-406
2/14/2022
3/1/2022
Shallow
685463.34
1412717.51
813.96
810.77
43.00
43.00
33.00
43.00
780.96
770.96
15.50
798.46
15.50
798.46
15.90
798.06
CLF23-407
2/15/2023
3/1/2022
Shallow
685796.44
1413229.69
828.87
826.33
43.00
43.00
33.00
43.00
795.87
785.87
23.53
805.34
24.05
804.82
24.51
804.36
CLF23-408
2/15/2023
3/1/2022
Shallow
685262.35
1413270.88
810.81
808.07
35.00
35.00
25.00
35.00
785.81
775.81
14.33
796.48
15.21
795.60
15.61
795.20
GWA-41)
6/12/2015
7/30/2021
Deep
686783.39
1411776.91
902.45
899.38
90.07
93.14
84.07
89.07
818.38
813.38
54.79
847.66
54.92
847.53
54.93
847.52
GWA-4S
5/19/2015
7/30/2021
Shallow
686776.57
1411777.34
901.97
898.98
67.99
70.98
52.19
67.19
849.78
834.78
54.89
847.08
55.11
846.86
55.18
846.79
MW-4
6/30/1989
7/30/2021
Shallow
686723.00
1414467.00
867.15
863.81
50.20
49.93
49.93
49.93
823.55
813.55
38.79
828.36
38.96
828.19
39.09
828.06
MW-4D
10/12/2006
7/30/2021
Bedrock
686715.00
1414462.00
866.74
863.42
64.18
67.55
56.65
61.65
807.87
802.87
39.10
1 827.64
39.30
827.44
39.35
827.39
ILF-21)
3/31/2019
7/30/2021
Deep
687699.24
1413205.78
885.14
885.57
107.00
106.57
91.57
101.57
793.57
783.57
41.42
843.72
4172
843.42
41.88
843.26
ILF-2S
IL-
3/31/2019
7/30/2021
Shallow
687699.26
I
1413214.68
884.79
885.21
52.00
51.58
41.58
51.58
843.21
833.21
43.88
840.91
44.15
840.64
44.33
840.46
Notes:
1 Well depths initially measured during well installation and updated as new wells are installed.
Z "Total Well Depth" is the depth to the bottom of the filter pack.
3 Values measured during well installation
BGS - Below ground surface
TOC - Top of casing
Ft - Feet
NAD 83 - North American Datum of 1983
NAVD 88 - North American Vertical Datum of 1988
NM - Not measured
Prepared by: GTC Checked by: CSM
Page 1 of 1

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
APPENDIX A
WATER -LEVEL MONITORING DATA FILES
INCLUDED AS EXCEL FILE)
L7
synTerra
Science & Engineering Consultants

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
APPENDIX B
GROUNDWATER MODEL PREDICTED TREND FILES
INCLUDED AS EXCEL FILE)
L7
synTerra
Science & Engineering Consultants

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
APPENDIX C
UNDERDRAIN PUMPING DATA FILES
INCLUDED AS EXCEL FILE)
L7
synTerra
Science & Engineering Consultants

Groundwater Conditions Quarterly Report — October 2023 to December 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
APPENDIX D
MANN-KENDALL DATA
INCLUDED AS EXCEL FILE)
L7
synTerra
Science & Engineering Consultants