1812_DukeMarshall_2023Q1_GWCR_FID1792115_20230426

(� DUKE
ENERGY
April 26, 2023
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 — January 2023 through March 2023
Industrial Landfill No.1
Permit No.: 1812-INDUS-2008
Marshall Steam Station
Terrell, North Carolina 28682
Dear Ms. Moutos:
526 South Church St.
Charlotte, NC 28202
Mailing Address
P.O. Box 1006
Mail Code EC 12J.
Charlotte, NC 28201-1006
In accordance with the NCDEQ DWM September 17, 2021, Phase 2 Permit Modification Approval letter, 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 January 2023 through March 2023 (Q1 2023).
The quarterly report includes an analysis of groundwater levels and dewatering pump flowrates within Phases
2, 3 and 4, with updated water level maps, hydrographs, pump flowrate plots, and well construction and water
level data tables. An evaluation of groundwater levels and pump flowrates compared to model predictions is
included. All groundwater transducer data, groundwater model trend data, and dewatering pump 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 (Q2 2023) will be submitted by August 1, 2023.
If you need additional information regarding this submittal do not hesitate to email or call Ashley Healy at
Ashley. Healy4)duke-energy.com or [phone].
Respectfully submitted,
Tyler Hardin, P.E.
Environmental Services
Attachments: Industrial Landfill No.1 (1812-INDUS-2008) Groundwater Conditions Quarterly Report —January
2023 through March 2023 (SynTerra; April 2023)
Appendices in excel format:
1) Appendix A Water Level Monitoring Data Files
2) Appendix B Groundwater Model Predicted Trend Files
3) Appendix C Dewatering/Underdrain Pumping Data Files
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
Ashley Healy, 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 -
JANUARY 2023 TO MARCH 2O23
INDUSTRIAL LANDFILL NO. 1
(1812-INDUS-2008)
FOR
MARSHALL STEAM STATION
8320 EAST CAROLINA HIGHWAY 150
TERRELL, NC 28682
APRIL 25, 2023
PREPARED FOR
DUKE
ENERGY
DUKE ENERGY CAROLINAS, LLC
NJ
Kathryn W. Webb, LG Thomas Colton
Senior Peer Reviewer Project Manager
i SEAL
1599 ; >- Craig Eady, NC LG #1599
A, Q. Senior Project Manager

Groundwater Conditions Quarterly Report — January 2023 to March 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
TABLE OF CONTENTS
SECTION 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 Dewatering and Underdrain Pump Performance.......................................................2-4
3.0 QUARTERLY WATER -LEVEL REDUCTION ACTIVITIES.................................................... 3-1
4.0 REFERENCES...............................................................................................................4-1
ril 2023 Page i
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
S1.1tel29LCT11Ci*1
Figure 1
Monitoring Location Map
Figure 2
Area of Focus Water -Level Map — Upper Flow Zone (March 2023)
Figure 3A
Background Monitoring Well Hydrographs (GWA-4S/D and MW-4/D)
Figure 313
Perimeter Hydrographs (MW-7 (013-3) and ILF-2S/D)
Figure 3C
Northwest of Cell 5 Hydrographs (CLF21-10 and CLF21-11)
Figure 3D
CLF-UD and Southwest of Cell 5 Hydrographs (CLF-UD and CLF21-12)
Figure 3E
East of Cell 6 Hydrographs (CLF21-14/R and CLF21-15)
Figure 3F
Future Phase 3 and 4 Hydrographs (CLF-301 and CLF-402)
Figure 3G
Cell 5 and Future Phase 5 (CLF21-13/R and CLF-401)
Figure 3H
South of Future Phase 3 Hydrographs (CLF-303 and CLF-304)
Figure 31
Phase 3 Hydrographs (CLF22-305 and CLF22-306)
Figure 3J
Within and South of Phase 4 Hydrographs (CLF22-307 and CLF23-405)
Figure 3K
Future Phase 4 and 5 Hydrographs (CLF23-406 and CLF23-407)
Figure 3L
Within Phase 4 Hydrographs (CLF23-408)
Figure 4A
Cell 5 (Underdrain) Pumping Flow Rate Vs. Simulated Flow Rate
Figure 413
Phase 3-5 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 Dewatering/Underdrain Pumping Data Files
Appendix D Mann -Kendall Data
ril 2023 Page ii
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
LIST OF ACRONYMS
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
reporting period
first quarter 2023 (January 2023 to March 2023)
Site
Marshall Steam Station
ril 2023 Page Hi
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 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
dewatering/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.
Data collected during the first quarter of 2023 (January 2023 to March 2023) 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, dewatering/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:
• Groundwater levels in the area have generally stabilized.
Water levels have been maintained at less than or approximately equal to modeled
predictions in most areas, with the exception of ten locations (CLF-301, CLF-303, CLF-
401, CLF-402, CLF21-12, CLF21-13R, CLF22-305, CLF22-306, CLF22-307, and ILF-2D).
During the reporting period, water levels were stable. Water levels higher than model
predictions generally represent the effects of a slower excavation rate than assumed in
the model.
• The Cell 5 underdrain pump has been operational for 19 months with an average
pumping rate of 10.3 gallons per minute (gpm). The Future Phases dewatering pump
flow rate averages of 55 gpm. 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 excavation rate has
contributed to the underdrain drying slower than predicted.
ril 2023 Page 1-1
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 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 March 30, 2023, for the upper (shallow) flow zone
and were used to generate a groundwater level map (Figure 2). No site -wide water level sweep
was performed for the first quarter 2023. 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).
• Some groundwater levels within and near the ILF have decreased slightly, relative to
groundwater levels from Quarter 4, 2022. However, most of the groundwater levels
near the ILF remain relatively similar in elevation to that of Quarter 4, 2022.
• 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 pump
transducers are used to monitor water -level trends (Figures 3A through 3J). The following are
key observations of overall trend data:
• Groundwater level data collected from July 2021 (when close monitoring started)
through March 2023 were evaluated using Mann -Kendall analysis to determine water -
level trends. Statistically significant decreasing trends were observed in 14 of 25
locations. A statistically significant increasing trend was observed at five locations (CLF-
303, CLF-304, CLF22-306, CLF22-307, CLF21-14), stable trends were observed at five
locations (CLF-305, CLF21-12, CLF23-405, CLF23-406, and ILF-21)). Because transducers
in CLF23-407 and CLF23-408 were recently installed, trend analysis could not be
performed.
Generally, increasing trends were observed in locations downgradient of the Future
Phases area. Increasing trends at CLF-303, CLF-304, CLF22-306, and CLF22-307 are
correlated with activities to prepare the lower portion of the ash basin for dredging
operations; additional ash creates slight increases of water levels.
ril 2023 Page 2-1
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 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:
• Monitoring locations GWA-4S/D and CLF21-10 are west of the ILF Phase 2
expansion (Figure 1). The shallow and deep flow zone water levels at those
locations have overall decreasing trends but were stable during the reporting
period (Figures 3A and 3C).
• ILF-2S/D are located north of the ILF (Figure 1). The shallow flow zone water
level has an overall decreasing trend while the deep flow zone water level is
stable (Figure 313).
MW-4/41D 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 but were stable during the reporting period
(Figure 3A).
Within the Phase 2 Expansion:
• A transducer, identified as CLF-UD, was installed to monitor the Cell 5
underdrain sump water level with the temporary pump operations (Figure 1). 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 3D).
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 and CLF21-13R have overall decreasing trends but were
stable during the reporting period. Water levels in CLF-21-12 are overall stable
and remained stable during the reporting period (Figures 3C, 3D, and 3G).
Monitoring locations CLF21-14R and CLF21-15 are west of Cell 6
(Figure 1). Water levels in CLF21-14R have an overall increasing trend. Water
levels in CLF21-15 had an overall decreasing trend. Water levels in both locations
remained stable during the reporting period (Figure 3E).
ril 2023 Page 2-2
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
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 have an overall decreasing
trend while CLF22-305 has no overall trend; both locations were stable during
the reporting period (Figures 3F and 31).
Downgradient of the Phase 2 Expansion (Future Phases Area):
• Monitoring location MW-7 (013-3) is downgradient of the ILF Phase 2 expansion
(Figure 1). Shallow water levels at MW-7 (013-3) have an overall decreasing trend
and were stable during the reporting period (Figure 313).
• 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 but were stable during the reporting period (Figures 3G
and 3F).
Monitoring locations CLF-303, CLF-304, CLF22-306, and CLF22-307 are
downgradient of the Future Phase 3 expansion (Figure 1). Shallow water levels at
those locations have overall increasing trends but were stable during the
reporting period (Figures 3H, 31, and 3J). Increasing trends at CLF-303, CLF-304,
CLF22-306, and CLF22-307 are correlated with activities to prepare the lower
portion of the ash basin for dredging operations; additional ash creates slight
increases of water levels.
• Monitoring locations CLF23-405, CLF23-406, CLF23-407, and CLF23-408 were
installed, in the Future Phases 3 and 4, during the reporting period. Water levels
in CLF23-405 and CLF23-406 were stable; water levels in CLF23-407 and CLF23-
408 were not able to be analyzed, due to insufficient water level data, however
the water levels appear stable or decreasing (Figure 3J, 3K, and 3L).
Monitoring locations CLF-303 and CLF-304 were abandoned during the reporting
period in order to prepare for excavation in the vicinity.
The discrepancy between model predictions and observed water levels is likely due to
the difference in the assumed schedule and rate for the excavation and dewatering
compared to the actual time to complete activities. Additionally, increasing trends at
CLF-303, CLF-304, CLF22-306, and CLF22-307 are correlated with activities to prepare
the lower portion of the ash basin for dredging operations. These activities include
relocating ash to the upper portion of the basin, just south of piezometers CLF-303, CLF-
304, CLF22-306, and CLF22-307. Relocating ash with the basin began in June 2022 and is
ongoing. This activity was not included in the calibration model assumptions.
Model predicted water levels for the new locations at CLF23-405, CLF23-406, CLF23-407,
CLF23-408 are not presented but will be added after the next reporting period.
ril 2023 Page 2-3
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 2023
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
2.3 Dewatering and Underdrain Pump Performance
Two excavation and construction dewatering pumps are installed within or downgradient of ILF
Phase 2, Cell 6, and the ILF Future Phases (Figure 1). An underdrain pump is installed within the
Cell 5 underdrain (CLF-UD). The Cell 6 pump no longer collects groundwater and only operates
for collection and removal of precipitation runoff; therefore, the Cell 6 pumping data will no
longer be reported. The remaining two pumps remove groundwater and, for the Future Phases
areas, precipitation runoff.
The Cell 5 underdrain pump does not receive precipitation runoff; the underdrain is enclosed.
Water removed by each pump is discharged to the lower portion of the ash basin.
The Cell 5 underdrain pumping and model -predicted dewatering rates are shown on
Figure 4A. Model -predicted and measured flow rates from the Future Phases excavation
dewatering pump are shown on Figure 4B.
The Cell 5 underdrain pump has been operational for 19 months, at an average pumping rate
for the reporting period of 10 gpm. The flow rate of the Future Phases dewatering pump
decreased to an average of 55 gpm from an average of 131 gpm. ILF Cell 5 and Future Phases
pumping data, including the calculated monthly total volume pumped and monthly average
flow rate, per location, are included in Appendix C.
Combined pumping operations for Cell 5 and the Future Phases area have removed
approximately 8.5 million gallons of water during the reporting period. For each pump, the
average flow rates for the reporting period and each month are listed below.
• The Cell 5 underdrain pump had an average flow rate of 10 gpm overall during the
reporting period and monthly average flow rates of:
o 9.6 gpm during January 2023
o 10.8 gpm during February 2023
o 10.6 gpm during March 2023
• The Future Phases pump had an average flow rate of 55 gpm overall during the
reporting period and monthly average flow rates of:
o 46.7 gpm during January 2023
o 52.6 gpm during February 2023
o 67.2 gpm during March 2023
ril 2023 Page 2-4
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 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:
Cell 5
• Underdrain operations continued, with an average flow rate of approximately 10 gpm.
• Cell 5 operations continue.
Cell 6
• Construction of Cell 6 is ongoing with installation of the secondary geocomposite and
primary geomembrane completed during the reporting period.
Future Phases
Excavation of coal combustion residuals (CCR) in the Future Phases continued during the
reporting period.
• Dewatering of excavation rim ditches is being maintained, with an average flow rate of
approximately 55 gpm.
ril 2023 Page 3-1
Project: 00.0083.46.05

Groundwater Conditions Quarterly Report — January 2023 to March 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 S, 2021.
ril 2023 Page 4-1
Project: 00.0083.46.05

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

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NOTES:
1, THE CLF-UD LOCATION WAS FORMERLY KNOWN AS CELL 5 PUMP.
2, ALL BOUNDARIES ARE APPROXIMATE.
3. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS APPROVED
BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2D77 [SAW-2015.01412)-
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o ■ WHEELER ENV] RD N MENTAL AND INFRASTRUCTU RE, I NC. NATU RAL RESOURCES
TECHNICAL REPORT [NRTR] DATED JUNE 2015.
4. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
5, THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD
NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED
Sgp BY TRANSASH.
v f 6. MAXAR SATELLITE IMAGERY OBTAINED FROM ESRI ONLINE. AERIAL WAS
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CAF . (IN FEET)
2osz DRAWN 8Y: 7, (SING DATE: 04/25/GROUNDWATER CONDITIONS QUARTERLY REPORT
REMSED BY. T. KING DATE:04/14/2023 JANUARY 2023 THROUGH MARCH 2O23
CHECKED BY.T COLTON DATE: 04/14/2023 MARSHALL STEAM STATION
APPROVED BY: T. COLTON DATE: 04/14/2023
synTerra PROJECT MANAGEFt:T.COLTON TERRELL, NORTH CAROLINA
www.synterracoro.com

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�'" w: d 4 '1 # - NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED
FUTURE BYTRANSASH.
7. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
0°° ,c' ',• AL-2S 8. ALL BOUNDARIES ARE APPROXIMATE.
9. AERIAL IMAGERY IS A COMBINATION OF DUKE ENERGY PROPELLERAERIAL
PHOTOGRAPHY COLLECTED ON JANUARY 9, 2023, AND MAXAR SATELLITE IMAGERY
8 -'1 ._ OBTAINED FROM ESRI ONLINE, COLLECTED ON AUGUST 23,2021.
p. ,-✓ �'-' q a ° e - ' -, (' 10. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE
4 S}• `I j `�+ _ ((( PLANE COORDINATE SYSTEM FIPS 3200 (NAD83).
j� �► - GRAPHIC SCALE
b8qQ� t � _' ' ° DUKE 200 o zoo 400 FIGURE 2
�' AREA OF FOCUS WATER -LEVEL MAP
4� ENERGY (IN FEET)
e . CAROLINAS UPPER FLOW ZONE (MARCH 2O23)
DRAWN BY. T. KING DATE: 05/12/2022
ry �� GROUNDWATER CONDITIONS QUARTERLY REPORT
�y�°r REVISED BY:T. KING DATE: 04/19/2023
,.; x _-, CHECKED BYT COLTON DATE: 04/19/2023 JANUARY 2023 THROUGH MARCH 2023
�� "• APPROVED BY. T. COLTON DATE: 04/19/2023
-� Y/� - PRDJEDTMANAGER:T.CGLTGN MARSHALL STEAM STATION
synTerra TERRELL, NORTH CAROLINA
www-s nterracor .com
~ P:\O ARCGIS PRO PROJECTS\DUKE ENERGY\MARSHALL\2023\GW CONDITIONS OUARTERLY REPORT\GW CONDITIONS OUARTERLY REPORT IAPRX

GWA-04S/D
M W-04/D
833
4
852
4
851
832
O
3
00
I O
3
0
Off.
�-
Q
850
Q
831
O
Z
O
Z
O
�
O
c
849
2
"
c
0
830
O
O
2
.2
O
>
>
c
d
O
°C
(V
O
i
.�
w
848
w
829
oG
847
°�'
828
M
M
827
0
846 0
8/1 /2021 12/1 /2021 4/1 /2022 8/1 /2022 12/1 /2022
8/1 /2021
12/1 /2021 4/1
/2022 8/1 /2022 12/1 /2022
Date
Date
GWA-04S - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -4.1 feet.
MW-04
- Total water level change from
transducer installation on 07/30/2021 to 013/31/2023 is -3.4 feet.
GWA-04D - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -4.2 feet.
MW-04D - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -3.8 feet.
GWA-04S/D
MW-04/D
837
858
855
—
00
o
a
834
a
--- ---
Z
Z
LL
LL
852
c
•.
— —
M
831
• Op
O
Obi
"'
O O
849
O o
O
�O O
w
Op
a�
v
J
p O
828
846
—
+,
c0
825
843
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022
6/1 /2021
12/1 /2021
6/1 /2022 12/1 /2022
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
BACKGROUND MONTIORING WELL HYDROGRAPHS—
Future Phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
ENERGY,
REVISED BY: D. AVARD
DATE:04/07/2023
INDUSTRIAL LANDFILL NO 1.
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet
ROLINAS
CHECKED BY: T. COLTON
DATE:04/12/2023
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in - inches
APPROVED BY:T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data)
2022
DULY 2022 - STEAM
Deep Groundwater Flow Zone (Transducer Data) ♦ Manual Water Level Measurement
PROJECT MANAGER: T. COLTON
ION
MARSHALL STEAM STATION
STATION
Bedrock Groundwater Flow Zone (Transducer Data) Daily Total Rainfall (inches)
synTerra
TERRELL NORTH CAROLINA
— — - Transient Groundwater Model Water Level Predicted Trend
www.synterracorp.com

MW-07 (OB-3)
819
818
00
00
a
> 817
z
4.
LL
c 816
v
w 815
v
v
J
L
814
c�
813
4
3
c
2
1
0
8/1 /2021 12/1 /2021 4/1 /2022 8/1 /2022 12/1 /2022
Date
MW-07 (013-3) - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -3.6 feet.
MW-07 (OB-3)
822
0 819
a
z
LPL
0 816
>
N
LU
G1
>
813
v
M
810 -L+--
6/1 /2021
r
12/1 /2021 6/1 /2022 12/1 /2022
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)
Deep Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement
- Transient Groundwater Model Water Level Predicted Trend Daily Total Rainfall (inches)
00
a
z
LL
C
0
c�
>
LL!
v
a�
J
L
a�
M
-
ILF-02S/D
846
845
844
843
842
841
840
4
3
C
4-
1
0
8/1 /2021 12/1 /2021 4/1 /2022 8/1 /2022 12/1 /2022
Date
ILF-02S - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -0.9 feet.
ILF-02D - Total water level change from transducer installation on 07/30/2021 to 03/31/2023 is -0.8 feet.
ILF-02S/D
849
846
843
840
837
ME
FT
pi Ulm
T III k
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022
Date
DUKE
ENERGY.
DRAWN BY: D. AVARD DATE: 07/21/2021
REVISED BY: D. AVARD DATE:04/07/2023
FIGURE 3b
PERIMETER HYDROGRAPHS - INDUSTRIAL LANDFILL NO 1.
CAROLINAS
CHECKED BY: T. COLTON DATE:04/12/2023
APPROVED BY: T. COLTON DATE: 04/12/2023
(1812-INDUS) PHASE 2 EXPANSION
GROUNDWATER CONDITIONS QUARTERLY REPORT
JULY 2022 - SEPTEMBER 2022
10,
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
sy1Tem
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF21-10
843
842
00
00
0
Q 841
Z
LLLL
O
a�
a�
838
c0
837
4
3
-71
2
4-
0
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
Date
CLF21-10 - Total water level change from transducer installation on 08/10/2021 to 03/31/2023 is -0.7 feet.
CLF21-10
846 -
00 843
0
Q
Z
LL
0 840
>
N
LU
Gl
837 -
a�
M
834
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
Date
CLF21-11
-
832
830
828
826
824
822
820
4
3
1
0
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
Date
CLF21-11- Total water level change from transducer installation on 08/09/2021 to 01/06/2023 is -4.9 feet.
CLF21-11
834
00
0
Q 831
Z
LL
C
O
828
a�
LU
G1
>
N
+; 825
822
0
0
000 o
�I
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
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
NORTHWEST OF CELL 5 HYDROGRAPHS- INDUSTRIAL LANDFILL NO 1.
ENERGY.
REVISED BY: D. AVARD
DATE:04/07/2023
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROI INAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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 �
www.synterracorp.com
TERRELL ' NORTH CAROLINA

:XI[:
00
00
0
a
z 814
+.
LL
G1
>
810
M
CLF-LID
��f��illl�l
4
3
%i
1
C
4-
c
-
0
11 /1 /2021 3/1 /2022 7/1 /2022 11 /1 /2022 3/1 /2023
Date
CLF-UD— Water level is stable during underdrain operations. Water levels spikes represent when pump was temporarily out of service.
CLF-LID
819
00 816
0
a
z
LL
0 813
>
N
W
Gl
>
J 810
a�
M
CLF21-12
824
823
822
821
820
819
818
„.
,IFr IF
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
Date
CLF21-12 - Total water level change from transducer installation on 10/03/2021 to 03/31/2023 is -4.7 feet.
CLF21-12
825
820
815
810
4
3
c
2 =
M
c
1
Ci7
M
Oc
807
805
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022
6/1 /2021
12/1 /2021
/1 /2022 12/1 /2022
Date
Dat
LEGEND
Cell 5 construction start (05/31/2021)
Notes:
DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3d
CLF-UD AND SOUTHWEST OF CELL 5 HYDROGRAPHS —
NAVD 88 — North American Vertical
ENERGY
REVISED BY: D. AVARD
DATE:04/12/2023
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
INDUSTRIAL LANDFILL NO 1.
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CAROLINAS
CHECKED BY: T. COLTON
DATE:04/12/2023
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data)
`�
PROJECT MANAGER: T. COLTON
JULY 2022 - SEPTEMBER 2022
- Transient Groundwater Model water level predicted trend
Manual Water Level Measurement
MARSHALL STEAM STATION
www.synterracorp.com
Daily Total Rainfall (inches)
Ta
TERRELL, NORTH CAROLINA

CLF21-14/R
823
822
00
00
a
> 821
z
4.
LL
0
W 819
a�
a�
818
c�
817
4
3
-71
2 _
�a
_
1
0
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
Date
CLF21-14R - Total water level change from transducer installation on 04/08/2022 to 01/06/2023 is +2.3 feet.
• • • • • CLF21-14 - Total water level change from transducer installation on 08/13/2021 to 03/22/2022 is -3.3 feet.
CLF21-14/R
830 -
a
00
> 825
a
z
LLLL
_
0
820
>
GJ
LU
Gl
>
N
J
815
M
810
6/1 /2021
Q�
CPvw/�
12/1 /2021 Date1 /2022 12/1 /2022
-
CLF21-15
827
826
O
O
825 Ig
824
O
823
O
O
822 _ IT
O II p O OI
821
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
Date
— CLF21-15 - Total water level change from transducer installation on 08/13/2021 to 03/31/2023 is -3.5 feet.
CLF21-15
828
825
822
819
816 ' 1 1-
6/1 /2021
0
O
S
12/1 /2021 6/1 /2022 12/1 /2022
Date
4
3
1
0
LEGEND
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 — North American Vertical
DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3e
EAST OF CELL 6 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1.
ENERGY.
REVISED BY: D. AVARD
DATE:04/07/2023
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROI INAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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)
sy1Tem
www.synterracorp.com
TERRELL
' NORTH CAROLINA

CLF-301
CLF-402
813
4
818
4
�Og
817
812
O
0000
O
3
00
g
3
'•�O
Op
Q
816
Q
811
Z
Z
-71
c
815
O D
2
.�-,
c
810
p
>
c
0>i
W
814
0
41110 6V64m,Uj
(V
809
a�
0>i
1
v
ai
1
J
J
813
0�'
808
c0
M
807
0
812 0
8/1 /2021 12/1 /2021 4/1 /2022 8/1
/2022 12/1 /2022
8/1 /2021
12/1 /2021 4/1
/2022 8/1 /2022 12/1 /2022
Date
Date
CLF-301- Total water level change from transducer installation on 07/27/2021 to 03/31/2023 is -3.8 feet.
CLF-402 - Total water level change from transducer installation on 07/27/2021 to 03/31/2023 is -4.5 feet.
CLF-301
CLF-402
819
815
O
\
• 00
0000
O
�00
O
816
oo
a
810
z
o
o o 'o
z
° o 0
0 0 o
V
o
0
813
a
805
\
+�
>
>
W
\
810
—
1
800
`
807
795
6/1 /2021
12/1 /2021 6/1 /2022
12/1 /2022
6/1 /2021
12/1 /2021
6/1 /2022 12/1 /2022
Date
Date
LEGEND
Notes:
f4w,, DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3f
Cell 5 construction start (05/31/2021)
NAVD 88 - North American Vertical
t ENERGY
REVISED BY: D. AVARD
DATE:04/07/2023
FUTURE PHASE 3 AND 4 HYDROGRAPHS - INDUSTRIAL LANDFILL NO 1.
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROLINAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
��
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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
www.synterracorp.com
TERRELL ' NORTH CAROLINA

CLF21-13/R
CLF-401
4
816 + 1.
4
822
'O
CLF21-13 was abandoned and replaced on
O O
820
November 4, 2021.
815
00
3
00
3
t7
�
♦
Q
818
814
Q
zM
z
♦
♦
LL
_
LPL
c
816
2
c
813
2
=.
o
o
cc
c0
W
814
W
812
°C
a�
J
1
v
J
♦
1
812
I
°�'
811
I A
co
cc
hill 1111111111
0
810
0
810
9/1 /2021 1 /1 /2022 5/1 /2022 9/1 /2022 1 /1 /2023
8/1 /2021
12/1 /2021 4/1
/2022 8/1 /2022 12/1 /2022
Date
Date
CLF21-13R - Total water level change from transducer installation on 11/08/2021 to 03/31/2023 is -1.6 feet.
CLF21-13 - Total water level change from transducer installation on 08/09/2021 to 10/01/2021 is -0.2 feet.
CLF-401- Total water level change from transducer installation on 07/27/2021 to 03/31/2023 is -4.8 feet.
CLF21-13/R
CLF-401
825
820
00
815
0
820
0 0 0•
a
0 0
0
o0
z
\ � o
z
o�A�
V
\
o
810
0
815
>
\
I
W
\
"'
805
W
\
;
>
\
J
I
810
+;
\
800
�
I
\
805
795
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
6/1 /2021
12/1 /2021
6/1 /2022 12/1 /2022
Date
Date
LEGEND Notes:
f4w,, DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3g
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical
t ENERGY,
REVISED BY: D. AVARD
DATE:04/07/2023
CELL 5 AND FUTURE PHASE 5 HYDROGRAPHS—
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
INDUSTRIAL LANDFILL NO 1.
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CAROLINAS
CHECKED BY: T. COLTON
DATE:04/12/2023
1812-INDUS PHASE 2 EXPANSION
� )
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data)
PROJECT MANAGER: T. COLTON
JULY 2022 - SEPTEMBER 2022
-
Transient Groundwater Model water level predicted trendManual Water Level Measurement
MARSHALL STEAM STATION
www.synterracorp.com
Daily Total Rainfall (inches)
Ta
TERRELL, NORTH CAROLINA

CLF-303
802
801
00
00
a
> 800
z
LLLL
�40>~
O
v
a�
a�
J
L
797
c0
796
4
3
-71
2
4-
c
1
0
8/1 /2021 12/1 /2021 4/1 /2022 8/1 /2022 12/1 /2022
Date
CLF-303 - Total water level change from transducer installation on 07/27/2021 to 01/11/2023 is +0.5 feet.
CLF-303
810
a
00 805
a
z
LPL
0 800
>
N
LU
Gl
>
795
a�
M
790
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022
Date
-
CLF-304
801
800
799
798
797
796
795
4
3
1
0
8/1 /2021 12/1 /2021 4/1 /2022 8/1 /2022 12/1 /2022
Date
CLF-304 - Total water level change from transducer installation on 07/27/2021 to 01/18/2023 is +0.2 feet.
CLF-304
807
804
801
798
A
�,>* <�>
-0��
795 ' I L
6/1 /2021
12/1 /2021
6/1 /2022 12/1 /2022
Date
LEGEND
Notes:
f4w,, DUKE
DRAWN BY: D. AVARD
DATE: 07/21/2021
FIGURE 3h
Cell 5 construction start (05/31/2021)
NAVD 88 - North American Vertical
�. ENERGY
REVISED BY: D.AVARD
DATE:04/07/2023
SOUTH OF FUTURE PHASE 3 HYDROGRAPHS -
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
�
NDUSTRIAL LANDFILL NO 1.
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CAROLINAS
CHECKED BY: T.COLTON
DATE:04/12/2023
1812-INDUS PHASE 2 EXPANSION
( �
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY:T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data)
,�,
PROJECT MANAGER: T. COLTON
JULY 2022 - SEPTEMBER 2022
- Transient Groundwater Model water level predicted trend
Manual Water Level Measurement
MARSHALL STEAM STATION
www.synterracorp.com
Daily Total Rainfall (inches)
WnTa
TERRELL NORTH CAROLINA

CLF22-305
CLF22-306
813
807
4
4
810
3
804
3
Q
Q
Z
AM
Z
++
k
c
+-;
c
c 807
c 801
♦
2 =
>
♦
♦ ♦
>
v
W
ca
(U
W
ca
d
ai 804
1
GJ
ai 798
1
J
J
GJ
G/
cc
M
tu801
795
11
11
Ll
0
0
3/1 /2022
5/1 /2022 7/1 /2022 9/1 /2022 11 /1 /2022 1 /1 /2023 3/1 /2023
3/1 /2022
5/1 /2022 7/1 /2022 9/1 /2022 11 /1 /2022 1 /1 /2023 3/1 /2023
Date
Date
CLF22-305 - Total water level change from transducer installation on 08/10/2021 to 03/31/2023 is +3.4 feet.
CLF22-306 - Total water level change from transducer installation on 08/13/2021 to 03/31/2023 is -0.01 feet.
CLF22-305
CLF22-306
816
808
810
0
°°
> 800
Q
\ �' O ♦
Z
Z
LL 804
\
0
o
+�
a 792
>
798
�
J
\
0 784
792
cc
\
786
776
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
Date
Date
CLF22-305 was
not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
CLF22-306 was not
used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
CLF22-305 (after
Transient Groundwater Model calibration)
CLF22-306 (after Transient
Groundwater Model calibration)
LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical
fillI DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3i
PHASE 3 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1.
ENERGY.
REVISED BY: D. AVARD DATE:04/07/2023
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
CAROI INAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CHECKED BY: T. COLTON DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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)
sy1Tem
www.synterracorp.com
TERRELL NORTH CAROLINA

CLF22-307
CLF23-405
806
4
807
4
804
3
804
3
0
�
Q
Q
z
z
LL
802
2 =
801
o
—
o
—
>
>
W
W
v 800
>798
1
J
J
cc
M
798
0
LLJI 11,
795 -
0
1
3//2022
1 1 1
5//2022 7//2022 9//2022 11 /1 /2022 1 /1 1 /2023 3//2023
12/1 /2022
1 /1 /2023 2/1 /2023 3/1 /2023
Date
Date
CLF22-307 - Total water level change from transducer installation on 04/08/2022 to 03/31/2023 is -1.8 feet.
CLF23-405 - Total water level change from transducer installation on 03/01/2023 to 03/30/2023 is -1.0 feet.
CLF22-307
CLF23-405
810
808
O
00
0 800
\
> 800
>
\
z
z
V
o
\
0 790
a 792
+�
>
>
W
W
>
Gl
>
�
J
qj
780
+; 784
770
776
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
6/1 /2021
12/1 /2021 6/1 /2022 12/1 /2022
Date
Date
CLF22-307 was
not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
CLF22-307 (after
Transient Groundwater Model calibration)
LEGEND Notes:
Cell 5 construction start (05/31/2021)
DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3j
WITHIN AND SOUTH OF PHASE 4 HYDROGRAPHS—
NAVD 88 — North American Vertical
ENERGY
REVISED BY: D. AVARD DATE:04/07/2023
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988
INDUSTRIAL LANDFILL NO 1.
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
CAROLINAS
CHECKED BY: T. COLTON DATE:04/12/2023
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON DATE: 04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Shallow Groundwater Flow Zone (Transducer Data)
`�
PROJECT MANAGER: T. COLTON
JULY 2022 - SEPTEMBER 2022
- Transient Groundwater Model water level predicted trendManual Water Level Measurement
MARSHALL STEAM STATION
www.synterracorp.com
Daily Total Rainfall (inches)
Ta
TERRELL, NORTH CAROLINA

CLF23-406
CLF23-407
810
4
810
4
807
�
3
807
3
0
�
Q
Q
Z
Z
O O
c
�
c
c 804
2
804
o
—
o
—
>
>
v
W
ca
W
W
ca
GJ
a>i 801
1
GJ
ai
801
I
1
J
J
M
M
798
0
798
0
12/1 /2022
1 /1 /2023 2/1 /2023
3/1 /2023
12/1 /2022
1 /1 /2023
2/1 /2023 3/1 /2023
Date
Date
CLF23-406 - Total water level change from transducer installation on 03/01/2023 to 03/30/2023 is -1.7 feet.
CLF23-407
- Total water level change from transducer installation on 03/01/2023 to 03/30/2023 is -0.2 feet.
CLF23-406
CLF23-407
815
815
00
00 810
a
810
Q
Z
Z
�
V
LPL
i
O
0 805
a
805
<*
+�
cc
>
W
>
W
W
>
Gl
>
�
J
J 800
800
i
GJ
+�+
M
f0
795
795
6/1 /2021
12/1 /2021 6/1 /2022
12/1 /2022
6/1 /2021
12/1 /2021
6/1 /2022 12/1 /2022
Date
Date
CLF22-307 was
not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of
CLF22-307 (after
Transient Groundwater Model calibration)
LEGEND
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 — North American Vertical
DUKE
DRAWN BY: D.AVARD
DATE:07/21/2021
FIGURE 3k
FUTURE PHASE 4 AND 5 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1.
ENERGY.
REVISED BY: D. AVARD
DATE:04/07/2023
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROI INAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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)
sy1Tem
www.synterracorp.com
TERRELL ' NORTH CAROLINA

CLF23-408
813
4
00
810
3
p
O O
Q
z
r-
807
2
Ci
Space Not Used
o
—
>
'ca
v
W
GJ
a>i
804
1
J
N
f0
. I
801
0
12/1 /2022
1 /1 /2023 2/1 /2023
3/1 /2023
Date
CLF23-408 - Total water level change from transducer installation on 03/21/2023 to 03/30/2023 is -0.3 feet.
CLF23-408
813
°°
810
>
Q
z
0
807
Space Not Used
v
W
Gl
>
804
a�
M
801
6/1 /2021
12/1 /2021 6/1 /2022
12/1 /2022
Date
LEGEND
Notes:
f4w,, DUKE
DRAWN BY: D.AVARD
DATE:07/21/2021
FIGURE 31
Cell 5 construction start (05/31/2021)
NAVD 88 — North American Vertical
t ENERGY
REVISED BY: D. AVARD
DATE:04/07/2023
WITHIN PHASE 4 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1.
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
CAROLINAS
(1812-INDUS) PHASE 2 EXPANSION
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:04/12/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
��
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
APPROVED BY: T. COLTON
DATE: 04/12/2023
JULY 2022 - SEPTEMBER 2022
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
www.synterracorp.com
TERRELL NORTH CAROLINA

140
3
■ Model Flow Rate (gpm)
_ Rainfall Daily Total (in)
X Actual Pumping Flow Rate (gpm)
120
Steady State Blanket Underdrain Model Flow
of 18 GPM as presented in Technical Memorandum:
E
t1A
Modeling Support for the ILF Phase 2 Permit to Construct Modifications
a� 100ro 0
�'
2
GC
X
U
�
80
X
x
o
•�
-0 60 ❑
ca
+�
N
x
•U
-0 ❑
X
1
v
j 40 ❑
xx
v
x
x xx
20'
I
x iiiii
0
0
9/1/2021
3/1/2022 9/1/2022 3/1/2023
Years of Operation
Notes:
1. gpm = gallons per minute.
2. Flow data from the first day following a period of no flow were not plotted.
DUKE
DRAWN BY: T. COLTON
DATE: 10/13/2021
FIGURE 4A
4 ENERGY
c
REVISED BY: D. AVARD
CHECKED BY: T. COLTON
DATE: 04/07/2023
DATE:04/07/2023
CELL 5 (UNDERDRAIN) PUMPING FLOW RATE VS. SIMULATED FLOW RATE
APPROVED BY: T. COLTON
DATE:04/07/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
46�
PROJECT MANAGER: T. COLTON
JANUARY 2023 THROUGH MARCH 2O23
synTerra
MARSHALL STEAM STATION
TERRELL, NORTH CAROLINA
www.synterracorp.com

500
A
Q
a0
a) 300
ra
oC
_O
LL 200
Ln
W
cN
r6
v 100
40
S
LL
3
■
x x x x
x
x ■ ■
x x x x
■
x x xx 2 _
x ■ V)
■ xx xx
x x ■ Wk v
■ x ■ xx )
■ x x
x O
ik. --wx
x x M 1 'a
'
x x x x +_xc x a
BSc �5c ■ yw v
o
SAIIIIIIIIIi-
-W. o
9/1/2021
3/1/2022
9/1/2022 3/1/2023
x Actual Pumping Flow Rate (gpm)
Years of Operation
■ Model Flow Rate (gpm)
Rainfall Daily Total (in)
Notes:
1. gpm = gallons per minute.
2. Flow data from the first day following a period of no flow were not plotted.
DUKE
DRAWN BY: T. COLTON
DATE: 10/13/2021
FIGURE 413
ENERGY
C .
REVISED BY: D. AVARD
CHECKED BY: T. COLTON
DATE: 04/07/2023
DATE: 04/07/2023
PHASE 3-5 PUMPING FLOW RATE VS. SIMULATED FLOW RATE
APPROVED BY: T. COLTON
DATE: 04/07/2023
GROUNDWATER CONDITIONS QUARTERLY REPORT
4�
PROJECT MANAGER: T. COLTON
JANUARY 2023 THROUGH MARCH 2O23
syrTerra
MARSHALL STEAM STATION
TERRELL, NORTH CAROLINA
www.synterracorp.com

Groundwater Conditions Quarterly Report — January 2023 to March 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
JANUARY 2023 THROUGH MARCH 2O23
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
2,3
Depth
(Ft-BGS)
Measured
1
Well Depth
(Ft-TOC)
Screened
3
Interval
(Ft TOC)
Top of
Screen
Elevation
(Ft-NAVD 88)
Bottom
of Screen
Elevation
(Ft-NAVD 88)
Water Level
Measurement
(Ft-TOC)
3/30/2023
Groundwater
Elevation
(Ft-NAVD 88)
3/30/2023
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
34.02
813.44
CLF-303
5/12/2021
7/27/2021
Shallow
684951.10
1413840.30
824.31
822.31
40.00
42.00
30.00
40.00
794.31
784.31
Decomissioned
CLF-304
5/24/2021
7/27/2021
Shallow
684062.20
1413563.40
823.28
821.28
60.00
62.00
50.00
60.00
773.28
763.28
Decomissioned
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
21.79
810.65
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
11.04
807.37
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
17.28
840.47
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
24.61
825.56
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
18.78
820.28
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
17.67
818.54
CLF21-14R
4/18/2022
4/18/2022
Shallow
686027.10
1414268.70
844.23
844.0
41.50
38.19
28.19
38.19
816.04
806.04
27.08
817.15
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
41.70
822.67
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
12.95
806.26
CLF22-306
3/22/2022
4/8/2022
Shallow
685033.00
1413752.34
816.36
813.57
25.00
25.00
15.00
25.00
801.36
791.36
14.18
802.18
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
24.52
801.44
CLF23-405
2/14/2022
3/1/2022
Shallow
684920.61
1413022.90
810.60
807.29
42.00
42.00
32.00
42.00
778.60
768.60
6.52
804.08
CLF23-406
2/14/2022
3/1/2022
Shallow
685463.34
1412717.51
814.20
810.77
43.00
43.00
33.00
43.00
781.20
771.20
9.38
804.82
CLF23-407
2/15/2023
3/1/2022
Shallow
685796.44
1413229.69
829.30
826.33
43.00
43.00
33.00
43.00
796.30
786.30
19.71
809.59
CLF23-408
2/15/2023
3/1/2022
Shallow
685262.35
1413270.88
810.98
808.07
35.00
35.00
25.00
35.00
785.98
775.98
7.24
803.74
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
54.58
847.87
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
55.10
846.87
MW-4
6/30/1989
7/30/2021
Shallow
686723.00
1414467.00
864.21
863.81
50.20
49.93
49.93
49.93
823.55
813.55
38.20
826.01
MW-4D
10/12/2006
7/30/2021
Bedrock
686715.00
1414462.00
864.52
863.42
64.18
67.55
56.65
61.65
807.87
802.87
38.60
825.92
MW-7 (013-3)
12/16/2010
7/30/2021
Shallow
685380.10
1414418.00
859.16
856.56
51.40
54.00
39.00
54.00
820.16
805.16
44.63
814.53
ILF-2D
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
41.51
843.63
ILF-2S
3/31/2019
7/30/2021
Shallow
687699.26
1413214.68
884.79
885.21
52.00
51.58
41.58
51.58
843.21
833.21
43.94
840.85
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
Prepared by: GTC Checked by: DAA
Page 1 of 1

Groundwater Conditions Quarterly Report — January 2023 to March 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 — January 2023 to March 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)
1
161P
synTerra
Science & Engineering Consultants

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

Groundwater Conditions Quarterly Report — January 2023 to March 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