1812_DukeMarshall_2024Q1_GWCR_FID1836259_20240501

(� DUKE
ENERGY
May 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 — January 2024 through March 2024
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 January 2024 through March 2024 (Q1 2024).
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 (Q2 2024) will be submitted by August 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 —January
2024 through March 2024 (SynTerra; May 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): Deana Yitbarek, NCDEQ
Elizabeth Werner, NCDEQ
Sherri Stanley, NCDEQ
Scott Saunders, Duke Energy
Dan Zakary, Duke Energy
Chris Varner, Duke Energy
Tyler Hardin, Duke Energy
Ed Sullivan, Duke Energy
Thomas Colton, SynTerra
www.duke-energy.com Page 2 of 2

L1
synTerra
Science & Engineering Consultants
synterracorp.com
GROUNDWATER CONDITIONS QUARTERLY REPORT -
JANUARY 2024 TO MARCH 2O24
INDUSTRIAL LANDFILL NO. 1
(1812-INDUS-2008)
FOR
MARSHALL STEAM STATION
8320 EAST CAROLINA HIGHWAY 150
TERRELL, NC 28682
APRIL 30, 2024
PREPARED FOR
L7 DUKE
Z ENERGY
DUKE ENERGY CAROLINAS, LLC
s;
r Z
Craig Eady, NC LG #1599 David Avard
Senior Peer Review �.�``tN CAROi'Project Scientist
SEAL =
056667
Thomas Colton, NC PE #056667
Associate Engineer

Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
ILV-ff*9]Y419Ly1111110Ill 0
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.......................................................2-1
2.3 Underdrain Pump Performance.................................................................................2-3
3.0 QUARTERLY WATER -LEVEL REDUCTION ACTIVITIES.................................................... 3-1
4.0 REFERENCES...............................................................................................................4-1
LIST OF FIGURES
Figure 1
Monitoring Location Map
Figure 2
Area of Focus Water -Level Map — Upper Flow Zone (April 2024)
Figure 3A
Upgradient of Phase 2 Expansion (ILF-2S/D and MW-4/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
Downgradient of the Phase 2 Expansion (CLF-401 and CLF-402)
Figure 3G
Downgradient of the Phase 2 Expansion (CLF22-306 and CLF22-307)
Figure 3H
Downgradient of the Phase 2 Expansion (CLF23-405 and CLF23-406)
Figure 31
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
A­;1
Page i
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
141.1919Iff_[4I:111l0lYa1.1
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
first quarter 2024 (January 2024 to March 2024)
Site
Marshall Steam Station
April 2024
Page ii
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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 first quarter of 2024 (January 2024 to March 2024) 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 at 20 piezometers and monitoring wells and the ILF
underdrain.
• Groundwater levels in the area are generally stable or decreasing.
• During the reporting period, water levels are stable or decreasing at 16 out of 20
locations; MW-4, MW-4D, CLF21-10, and CLF21-14R exhibit increasing trends 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 and
increased precipitation during the reporting period.
• The Cell 5 underdrain pump has been operational for 31 months with an average
pumping rate of 7.6 gallons per minute (gpm). During the reporting period, the pumping
rate continued to decrease, (7.9 gpm average in January through 7.2 gpm average in
March). 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.
Ap ri 1 2024
Page 1-1
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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 April 1, 2024, for the upper (shallow) flow zone
and were used to generate a groundwater level map (Figure 2). 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 4, 2023.
• 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
March 2024 (Figures 3A through 31). The following are key observations of overall trend data:
• Groundwater level data collected from July 2021 (when close monitoring started)
through March 2024 were evaluated using Mann -Kendall analysis to determine water -
level trends (Appendix D). Statistically significant decreasing overall trends were
observed in 17 of 20 locations. At the remaining locations (CLF21-11, CLF21-12 and
CLF21-14/R), an overall stable trend was observed .
• Generally, decreasing or stable trends were observed in locations downgradient of the
Future Phases area during the reporting period (January 2024 through March 2024).
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 31). Appendix B contains Excel spreadsheets with the
predicted transient groundwater level trends exported from the models.
April 2024
Page 2-1
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
Upgradient of the Phase 2 Expansion:
Water levels upgradient of the Phase 2 Expansion are generally stable or increasing with
the exception of ILF-2S which has a decreasing trend during the reporting period. Water
levels at MW-4, MW-41), and CLF21-10 all increased during the reporting period despite
overall decreasing trends. These trends are likely the result of increased precipitation
during the reporting period. Information regarding the water level trends for the
reporting period and overall monitoring period are detailed below.
Location
ID
Flow
Zone
Reporting
Period Trend
Overall
Trend
Location
Plot
MW-4
Shallow
Increasing
Decreasing
East of the ILF Phase 2 expansion
Figure 3A
MW-4D
Deep
Increasing
Decreasing
East of the ILF Phase 2 expansion
Figure 3A
ILF-2S
Shallow
Decreasing
Decreasing
North of the ILF
Figure 3A
ILF-2D
Deep
Stable
Decreasing
North of the ILF
Figure 3A
GWA-4 S
Shallow
Stable
Decreasing
West of the ILF Phase 2 expansion
Figure 3B
GWA-4D
Deep
Stable
Decreasing
West of the ILF Phase 2 expansion
Figure 3B
CLF21-10
Shallow
Increasing
Decreasing
West of the ILF Phase 2 expansion
Figure 3B
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:
Water levels at the perimeter of the Phase 2 Expansion are decreasing or stable, apart
from CLF21-14R which increased during the reporting period, despite a stable trend
overall. This increase is likely the result of increased precipitation during the reporting
period. Information regarding the water level trends for the reporting period and overall
monitoring period are detailed below.
Location ID
Flow
Zone
Reporting
Period Trend
Overall
Trend
Location
Plot
CLF21-11
Shallow
Stable
Stable
West of Cell 5
Figure 3C
CLF21-12
Shallow
Stable
Stable
Southwest of Cell 5
Figure 3D
CLF21-13R
Shallow
Decreasing
Decreasing
South of Cell 5
Figure 31)
CLF21-14R
Shallow
Increasing
Stable
East of Cell 6
Figure 3E
CLF21-15
Shallow
Stable
Decreasing
East of Cell 6
Figure 3E
Ap ri 1 2024
Page 2-2
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
Downgradient of the Phase 2 Expansion (Future Phases Area):
Water levels downgradient of the Phase 2 Expansion are decreasing or stable.
Information regarding the water level trends for the reporting period and overall are
detailed below.
Location
Flow
Reporting
Overall
Location
Plot
ID
Zone
Period Trend
Trend
CLF-401
Shallow
Stable
Decreasing
Within Future Phases 4 & 5 Expansion
Figure 3F
CLF-402
Shallow
Stable
Decreasing
Within Future Phases 4 & 5 Expansion
Figure 3F
Downgradient of the Future Phase 3
CLF22-306
Shallow
Stable
Decreasing
Figure 3G
Expansion
Downgradient of the Future Phase 3
CLF22-307
Shallow
Decreasing
Decreasing
Figure 3G
Expansion
CLF23-405
Shallow
Decreasing
Decreasing
In the Future Phase 3 and 4
Figure 3H
CLF23-406
Shallow
Decreasing
Decreasing
In the Future Phase 3 and 4
Figure 3H
CLF23-407
Shallow
Decreasing
Decreasing
In the Future Phase 3 and 4
Figure 31
CLF23-408
Shallow
Decreasing
Decreasing
In the Future Phase 3 and 4
Figure 31
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 pumping rates are shown on Figure 4.
The Cell 5 underdrain pump has been operational for 31 months, at an average pumping rate
for the reporting period of 7.6 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 0.9 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 7.6 gpm overall during the
reporting period and monthly average flow rates of:
o 7.9 gpm during January 2024
o 7.7 gpm during February 2024
o 7.2 gpm during March 2024
April 2024
Page 2-3
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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 7.6 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 was received on December 29, 2023.
• The ILF Phase 3 construction is anticipated to start by Summer 2024.
Future Phases
• Passive dewatering and excavation of coal combustion residuals (CCR) in the Future
Phases continued during the reporting period.
April 2024
Page 3-1
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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.
April 2024
Page 4-1
Project: 00.0083.46.11

Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
FIGURES
L7
synTerra
Science & Engineering Consultants

_ ILF-2S
840.27
t/
a
GWA-4S
846.86 ��
,t
t
s +.
r
85p 827.5
CLF21-11
825.95
' '20 822.5
CLF
�o
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82022
t % CLF21-13R -'J8
s 815.35 L
8
CLF-401a1o` CLF23-407
sa0: ii►'° 804.41 Bos 802.87 1-
y,1-�...4300 o. CLF-40
799.78
.cy, _'CLF23`406
CLF23 408�� J
794
CLF22-306
794.06
CLF23-405
794.31
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5
LEGEND
MW-4
�
y,`
ie 828.66
Mw-ss WELL ID
�r'r.f
•y
7s5.8o WATER LEVEL (NAVD 88, FEET)
r
t
BACKGROUND MONITORING WELL
MONITORING WELL
if - yw:j,!
C PIEZOMETER
CLF21-15
UNDERDRAIN PUMP
823.38
INFERRED WATER LEVEL CONTOUR (2.5' INTERVAL)
GROUNDWATER FLOW DIRECTION
`
FUTURE PHASES
-F21-14R
ASH BASIN WASTE BOUNDARY
9.77
— - — GEOGRAPHIC LIMITATION
8�0
LANDFILL COMPLIANCE BOUNDARY
$tio
STRUCTURAL FILL BOUNDARY
LANDFILL BOUNDARY
LANDFILL CELL 5 AND 6 BOUNDARY
LEACHATE BASIN
DUKE ENERGY CAROLINAS PROPERTY LINE
TOPOGRAPHIC CONTOUR (10' INTERVAL)
r
> STREAM (MCKIM & CREED)
. ,
WETLAND (MCKIM & CREED)
NOTES:
1. WATER LEVELS WERE COLLECTED ON 411124.
1
2. ELEVATIONS ARE REFERENCED TO THE NORTH AMERICAN VERTICAL DATUM OF
\
o
1988 (NAVD 88).
3. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS
APPROVED BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2017
(SAW-2015-01412). WETLANDS AND STREAMS BOUNDARIES WERE OBTAINED FROM
T
AMEC FOSTER WHEELER ENVIRONMENTAL AND INFRASTRUCTURE, INC. NATURAL
o
RESOURCES TECHNICAL REPORT (NRTR) DATED JUNE 2015.
-
4. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD
NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED
o
BYTRANSASH.
5. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
6. ALL BOUNDARIES ARE APPROXIMATE.
7. AERIAL IMAGERY ISA COMBINATION OF DUKE ENERGY PROPELLER AERIAL
-
PHOTOGRAPHY COLLECTED ON MARCH 11, 2024, AND MAXAR SATELLITE IMAGERY
OBTAINED FROM ESRI ONLINE, COLLECTED ON AUGUST 23, 2021.
B. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM HIPS 3200 (NAD83).
zoo GO400 RAP
\\ FIGURE 2
DUKE AREA OF FOCUS WATER -LEVEL MAP
ENERGY. (IN FEET)
CAROLINAS UPPER FLOW ZONE
DRAWN EY=T LUNG DATE=05/12/2022 GROUNDWATER CONDITIONS QUARTERLY REPORT
REVISED BY L FOREMAN DATE=04/11/2024
CHECKED BY T-001TON HATE=oa/u/2o24 JANUARY 2024 THROUGH MARCH 2O24
APPROVED BY COLTON DATE=04/11/2024 MARSHALL STEAM STATION
synTerra PROJECT MANAGER ICOLTON TERRELL, NORTH CAROLINA
www.svnterracoriD.com
GAO ARCGIS PRO PROJECTS\DUKE ENERGY\MARSHAL_\2023\GW CONDITIONS QUARTERLY REPORT\GW CONDITIONS OUARTERLY REPORT 04 APRX

ILF-02S/D
MW-04/D
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842 -
840 -
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838 - , - , - I I I I ,
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
ILF-02S - Total water level change from transducer installation on 07/30/2021 to 04/01/2024 is -2.0 feet.
ILF-02D - Total water level change from transducer installation on 07/30/2021 to 04/01/2024 is -1.8 feet.
ILF-02S/D
849 T.-
846
843
840
O' • O O
O or
837 -L-�--
6/1 /2021
12/1/2021 6/1/2022 12/1/2022 6/1/2023 12/1/2023
Date
0
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-
834
832
830
828
826 , . - , L-
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
MW-04 - Total water level change from transducer installation on 07/30/2021 to 04/01/2024 is -4.1 feet.
MW-04D - Total water level change from transducer installation on 07/30/2021 to 04/01/2024 is -4.1 feet.
MW-04/D
E:1C1rA
834
831
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825
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
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LEGEND Notes:
Cell 5 construction start (05/31/2021) NAVD 88 -North American Vertical
If DUKE
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:03/25/2024
UPGRADIENT OF PHASE 2 EXPANSION HYDROGRAPHS
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet
,RDLINAS
CHECKED BY: T. COLTON DATE:03/25/2024
INDUSTRIAL LANDFILL NO 1. 1812-INDUS
Cell 5 Blanket Underdrain construction completion (10/22/2021)
GROUNDWATER CONDITIONS QUARTERLY REPORT
6-7
Shallow Groundwater Flow Zone (Transducer Data) in - inches
APPROVED BY:T. COLTON DATE:03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
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)
synTerra
TERRELL, NORTH CAROLINA
- Transient Groundwater Model Water Level Predicted Trend
www.synterracorp.com

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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
GWA-04S - Total water level change from transducer installation
on 07/30/2021 to 04/01/2024 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 04/01/2024 is -4.3 feet.
GWA-04S/D
CLF21-10
844
855
00
00
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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
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 —North American Vertical
r DUKE
DRAWN BY: D. AVARD
DATE:07/21/2021
FIGURE 3B
Future Phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
�. ENERGY;
REVISED BY: D. AVARD
DATE:03/25/2024
UPGRADIENT OF PHASE 2 EXPANSION HYDROGRAPHS
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
,ROLINAS
CHECKED BY: T. COLTON
DATE:03/25/2024
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:03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
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)
synTerra
TERRELL, NORTH CAROLINA
- Transient Groundwater Model Water Level Predicted Trend
www.synterracorp.com

CLF-LID
CLF21-11
818
816
00
0
Q
z 814
c
0
> 812
aJ
W
GJ
v
J
810
v
M
0
3
oil
1
c
808 , T , --------- L 0
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /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 -TT—
a
0 816
a
z
ILL
W
GJ
>
GJ
L 810
v
c0
I" J u-1 ■1 du p1 I10-1 i JE1,111 II NIII 11111111J 11 IN 11111L11..b11 Ii11111.1
8O7 � T �� �� T �T
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
830
00 828
O
O
Q
z
c 826
2
ca
>
OJ
Uj
N
ai 824
z.
I
aM.II
-
1u 1
4
3
c
M
c
1
822 -4m 0
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF21-11- Total water level change from transducer installation on 08/09/2021 to 04/01/2024 is -4.7 feet.
CLF21-11
828
I:3OZ:2
824
1:3040A
H2O I'Pu-"dA "'- 1JI!T ■1mm1111�I11-i� -J ala 11 IINIII YIEIJ 11NdIM111111 JL0.a L1111 �11 {i111
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
LEGEND Notes:
DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE3C
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
r. � ENERGY,,,
RDLINAS
REVISED BY: D. AVARD DATE:03/25/2024
CHECKED BY: T. COLTON DATE:03/25/2024
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
s NT a
'�/I 1
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)
APPROVED BY: T. COLTON DATE:03/25/2024
PROJECT MANAGER:T.COLTON
JANUARY 2024 THROUGH MARCH 2O24
MARSHALL STEAM STATION
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF21-12
CLF21-13/R
824 -
�
822
t7
a
z
0 820
M
d
W
aJ
J 818 -
L
M
i
816 -, -,
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF21-12 - Total water level change from transducer installation on 08/09/2021 to 04/01/2024 is -2.4 feet.
0
i
0 8,
a
z
c
8'
>
aJ
W
v
>
aJ
L 8
N
M
805
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
0
3
2 =
1
N
i
i
00
0
a
z
0
>
a,
W
a�
>
W
J
W
(a
822 -
820 -
818 -
816 -
CLF21-13 was abandoned and replaced on
November 4, 2021.
p i O O
�O
JIL
91
3
c
2
1
814 0
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF21-13R - Total water level change from transducer installation on 11/08/2021 to 04/01/2024 is -3.2 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
O O O
810
E:11*'11111111
800 11FU-11iJ 1.1. lld1T ■1001111T IlN-1 .1 111.111 11 dill YmJ 11-111i 11111111Lm.b. P1111 �11 apaill
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
ra
c
fY
LEGEND Notes:
DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE3D
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
r. � ENERGY,,,
RDLINAS
REVISED BY: D. AVARD DATE:03/25/2024
CHECKED BY: T. COLTON DATE:03/25/2024
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
synTerra
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)
APPROVED BY: T. COLTON DATE:03/25/2024
PROJECT MANAGER:T.COLTON
JANUARY 2024 THROUGH MARCH 2O24
MARSHALL STEAM STATION
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF21-14/R
CLF21-15
822
4
828
4
O
821 O
00
O
3
ZF 00
826
3
O
Q
O
Q
The CLF21-15transducer
Z
820
Z
was removed in April 2023
O
and replaced in July 2023
c
♦
O
2-
c
824
O
2-
Q
�a
819 : O I O
I 110
R
>
p �
W
♦
W
QD
cc
ai
0O QO 0'
ai
I I
1
822
v
818 ♦ O
I I
L
�
++
M
a+
ca
817
0
820
6
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
CLF21-14R - Total water level change from transducer installation
on 04/08/2022 to 04/01/2024 is +1.4
feet.
CLF21-15 - Total water level change from transducer installation on 08/13/2021 to 04/01/2024 is -2.8 feet.
• • • • • CLF21-14 - Total water level change from transducer installation on 08/13/2021 to 03/22/2022 is -3.3 feet.
Total water level change from transducer installation on 07/31/2023 to 12/31/2023 is -0.9 feet.
CLF21-14/R
CLF21-15
828
828
00
O
00
0
824
C
Q
825
O
— 8
Z
o o
c
o0 0
820
��
M
822
o
M
0
�♦ 0 O
o
O
—
v
p O 0
w
w
>
J
L
816
L
819
v
M
3
812
816
A JL
U
R.I. h L
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:
DUKE
DRAWN BY: D.AVARD
DATE:07/21/2021
FIGURE3E
Cell 5 construction start (05/31/2021)
NAVD 88 — North American Vertical
r. �
ENERGY,,,
REVISED BY: D. AVARD
DATE:03/25/2024
WITHIN PHASE 2 EXPANSION HYDROGRAPHS
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
RDLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft -Feet
CHECKED BY: T. COLTON
DATE:03/25/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
Cell 5 Blanket Underdrain construction completion (10/22/2021)
in -inches
Shallow Groundwater Flow Zone ( Transducer Data)
APPROVED BY: T. COLTON
DATE:03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
-
♦
Manual Water Level Measurement
PROJECT MANAGER: T.
MARSHALL STEAM STATION
Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)
s NT a
'�/I 1
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF-401
CLF-402
819
816
0
> 810
v
W
al
aJ
J
L 807
M
0 p e
O 0p
�O 0
4
3
�:
1
804 --1" 0
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF-401- Total water level change from transducer installation on 07/27/2021 to 04/01/2024 is -10.8 feet.
CLF-401
F-15K
ao 814
00
0
a
z
LL 809
ca
a' 804
W
794 -LP
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
c
i
i
00
0
a
z
0
M
a)
W
a�
i
W
J
W
fa
-
814 -
1.11s!
805 -
802 -
'rZ'T'11111110
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
CLF-402 - Total water level change from transducer installation on 07/27/2021 to 04/01/2024 is -11.4 feet.
The water level dropped below the transducer elevation 11/05/2023.
CLF-402
815 r
810
E:16a
:M
VAS-J.y
�moa mA m
\ a
790 11`0J-11dA u'.l- hilT ■nam IlT I1m.aux 11 11,1111 Yu nu �11-111r 111111 YILu.r P1�n 1Jl111
6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 12/1 /2023
Date
91
3
►i
1
R
LEGEND Notes:
DUKE
DRAWN BY: D.AVARD DATE:07/21/2021
FIGURE 3F
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
r. � ENERGY,,,
RDLINAS
REVISED BY: D. AVARD DATE:03/25/2024
CHECKED BY: T. COLTON DATE:03/25/2024
DOWNGRADIENT OF THE PHASE 2 EXPANSION
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
GROUNDWATER CONDITIONS QUARTERLY REPORT
`�
s NT a
'�/I 1
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)
APPROVED BY: T. COLTON DATE:03/25/2024
PROJECT MANAGER:T.COLTON
JANUARY 2024 THROUGH MARCH 2O24
MARSHALL STEAM STATION
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF22-306
CLF22-307
804
r 4
807 -
4
�
801
- 3
ZF
804 -
3
00
Q
a
801 -
z
z
c
�
c
c
798
- 2
2
o
—
2
798 -
—
c�o
>
>
W
W
'@
@
795 -
J
795
11110111
L
L
3
792 -
792 .
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
CLF22-306 - Total water level change from transducer installation on 08/13/2021 to 04/01/2024
is -8.3 feet.
CLF22-307 -Total water level change from transducer installation on 04/08/2022 to 04/01/2024 is -9.3 feet.
CLF22-306
CLF22-307
808
810
00
00
803
O
O
p
805
p
CLF22-307 was not
Z
p p
used in the
Q
��
Transient
z
`
v
Groundwater
LL
798
OD
800 `
Model calibration,
O
water level
predictions were
o
prepared
a793
W
795
following
W
>
installation of
`
CLF22-307 (after
J
`
N
Transient
W
788
?�
790
O
Groundwater
I
Model calibration)
783
785
6/1 /2021
12/1 /2021 6/1 /2022 1 022 6/1 /2023 12/1 /2023
6/1 /2021 12/1 /2021 6/1 /2022 /2022 6/1 /2023 12/1 /2023
Dae
D1 {/e1
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
Cell 5 construction start (05/31/2021)
Notes:
NAVD 88 - North American Vertical
The modeled water levels are truncated
based upon the expected shutdown of
DUKE
DRAWN BY: D. AVARD DATE:07/21/2021
FIGURE 3G
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.,
REVISED BY: D. AVARD DATE:03/25/2024
Future phases 3 through 5 CCR excavation start (06/18/2021)
Datum 1988
the Cell 5 underdrain pumping
CAROLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021)
Ft - Feet
operation. The slower basin excavation
CHECKED BY: T.COLTON DATE:03/25/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
Cell 5 Blanket Underdrain construction completion (10/22/2021) rate has extended the period needed to
in -inches p
APPROVED BY: T. COLTON DATE: 03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
-
Shallow Groundwater Flow Zone (Transducer Data)
Manual Water Level Measurement
operate the underdrain and will delay
�
PROJECT MANAGER:T. COLTON
MARSHALL STEAM STATION
Transient Groundwater Model water level predicted trend
Daily Total Rainfall (inches)1Term
the shutdown of the Cell 5 underdrain
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF22-405
CLF23-406
4
810
4
806 -
807
00 803 -
3
ZF
00
3
z
z
804
I
c
S
= 800 -
2
2 =_
o
—
o
—
c�o
>
_
> 801
=
W\AllW
1
II
a�>i
v 797 -
798 I
l
M
794 - ,
0
795A
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 04/01/2024 is -10.4
feet.
CLF23-406 - Total water level change from transducer installation on 03/01/2023 to 04/01/2024 is -10.9
feet.
CLF22-405
CLF23-406
812
818
_
00
00
c 804
` o
0
a 810
z
Z
4.;
O
�O
o 0♦,
`
796
O
802 p
M
O
W
W
N
>
J ` 0
i 788
`
794
+�
I
780
ALI
786 -1111
6/1 /2021
12/1 /2021 6/1 /2022 1 1 022 6//2023 12/1 /2023
6/1 /2021 12/1 1 /2021 6//2022 1 /2022 6//2023 12/1 /2023
Date
D1 }/e1
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: The modeled water levels are truncated
Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical based upon the expected shutdown of
DUKE
DRAWN BY: D. AVARD DATE:07/21/2021
FIGURE 3H
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.,
REVISED BY: D.AVARD DATE: 03/25/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 the Cell 5 underdrain pumping
CAROLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet operation. The slower basin excavation
CHECKED BY: T. COLTON DATE: 03/25/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
Cell 5 Blanket Underdrain construction completion (10/22/2021) rate has extended the eriod needed to
in -inches p
APPROVED BY: T. COLTON DATE: 03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
Shallow Groundwater Flow Zone (Transducer Data) operate the underdrain and will delay
-Transient � Manual Water Level Measurement
�
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
Groundwater Model water level predicted trend the shutdown of the Cell 5 underdrain
Daily Total Rainfall (inches)
synTerra
TERRELL, NORTH CAROLINA
www.synterracorp.com

CLF23-407
CLF23-408
4
4
810
806 -
O�
O
J
00 808
3
803 -
3
z
z
c
�
c
=-
c 806
2 �=
c 800 - 2
o —
o
—
>
>
W
W
Gl
ai
1
N
ai 797 - 1
J
804
J
L
L
802
0
794 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 04/01/2024 is -6.2 feet.
CLF23-408 - Total water level change from transducer installation on 03/21/2023 to 04/01/2024 is -9.3 feet.
CLF23-407
CLF23-408
818
812
00
0 812
a 805
Q
Z O
Z
O
*3
C O
o �
806
798 — �p
+�
SOD
a)
�O
a >i
a)
uJ
LLIO.
@
v
>
W
J
i 800
4-1 791
MJI
I
I
!I
794
ALIWfi�AuiIl784
i
III— All I
6/1 /2021
12/1 /2021 6/1 /2022 1 022 6/1 /2023 12/1 /2023
6/1 /2021 12/1 /2021 6/1 /2022 /2022 6/1 /2023 12/1 /2023
Date
D1 {/e1
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: The modeled water levels are truncated
Cell 5 construction start (05/31/2021) NAVD 88 - North American Vertical based upon the expected shutdown of
DUKE
DRAWN BY: D. AVARD DATE:07/21/2021
FIGURE 31
DOWNGRADIENT OF THE PHASE 2 EXPANSION
ENERGY.,
REVISED BY: D. AVARD DATE:03/25/2024
Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 the Cell 5 underdrain pumping
CAROLINAS
INDUSTRIAL LANDFILL NO 1. (1812-INDUS)
Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet operation. The slower basin excavation
CHECKED BY: T.COLTON DATE:03/25/2024
GROUNDWATER CONDITIONS QUARTERLY REPORT
Cell 5 Blanket Underdrain construction completion (10/22/2021) rate has extended the eriod needed to
in -inches p
APPROVED BY: T. COLTON DATE: 03/25/2024
JANUARY 2024 THROUGH MARCH 2O24
Shallow Groundwater Flow Zone (Transducer Data) operate the underdrain and will delay
- Manual Water Level Measurement
�
PROJECT MANAGER: T. COLTON
MARSHALL STEAM STATION
Transient Groundwater Model water level predicted trend the shutdown of the Cell 5 underdrain
Daily Total Rainfall (inches)1Term
TERRELL, NORTH CAROLINA
www.synterracorp.com

aA
v
ne
LL-
N
C=
Ln
N
U
140
120
100
ie
c
x
n
3
2
1
X
9/1/2021 3/1/2022 9/1/2022 3/1/2023 9/1/2023 3/1/2024
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.
DUKE DRAWN BY: T. COLTON DATE: 10/13/2021 FIGURE 4
ENERGY REVISED BY: D. AVARD DATE:04/08/2024 CELL 5 (UNDERDRAIN) PUMPING FLOW RATE VS. SIMULATED FLOW RATE
CAROLINAS CHECKED BY: T.COLTON DATE:04/09/2024
APPROVED BY: T. COLTON DATE: 04/09/2024 GROUNDWATER CONDITIONS QUARTERLY REPORT
PROJECT MANAGER: T. COLTON JANUARY 2024 THROUGH MARCH 2O24
MARSHALL STEAM STATION
synTerra www.synterracorp.com TERRELL, NORTH CAROLINA

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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 2024 THROUGH MARCH 2O24
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
DepthZ'a
(Ft-BGS)
Measured
Well Depths
(Ft-TOC)
Screened
Intervala
(Ft-TOC)
Top of
Screen
Elevation
(Ft-NAVD 88)
Bottom
of Screen
Elevation
(Ft-NAVD 88)
Water Level
Measurement
(Ft-TOC)
01/05/2024
Groundwater
Elevation
(Ft-NAVD 88)
01/05/2024
Water Level
Measurement
(Ft-TOC)
02/06/2024
Groundwater
Elevation
(Ft-NAVD 88)
02/06/2024
Water Level
Measurement
(Ft-TOC)
03/18/2024
Groundwater
Elevation
(Ft-NAVD 88)
03/18/2024
Water Level
Measurement
(Ft-TOC)
04/01/2024
Groundwater
Elevation
(Ft-NAVD 88)
04/01/2024
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
27.04
805.40
26.96
805.48
27.79
804.65
28.03
804.41
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
17.24
801.17
17.90
800.51
18.44
799.97
18.63
799.78
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
17.80
839.95
17.46
840.29
17.32
840.43
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
24.60
825.57
24.23
825.94
24.21
825.96
24.22
825.95
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
18.92
820.14
18.34
820.72
18.77
820.29
18.84
820.22
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
18.46
817.75
18.27
817.94
20.28
815.93
20.86
815.35
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
28.45
819.09
28.07
819.47
27.88
819.66
27.77
819.77
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
41.10
823.27
41.11
823.26
41.11
823.26
40.99
823.38
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
Inaccessible
21.71
794.65
22.16
794.20
22.30
794.06
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
Inaccessible
33.38
792.58
34.05
791.91
34.31
791.65
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
Inaccessible
15.25
795.04
15.74
794.55
15.98
794.31
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
15.90
798.06
17.07
796.89
17.53
796.43
17.82
796.14
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
24.51
804.36
25.09
803.78
25.75
803.12
26.00
802.87
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
15.61
795.20
15.93
794.88
16.41
794.40
16.63
794.18
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
54.93
847.52
54.79
847.66
54.75
847.70
54.69
847.76
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
55.18
846.79
55.14
846.83
55.15
846.82
55.11
846.86
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
39.09
828.06
38.87
828.28
38.65
828.50
38.49
828.66
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
39.35
827.39
39.18
827.56
38.97
827.77
38.91
827.83
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
1 783.57
41.88
843.26
41.91
843.23
41.96
843.18
42.00
843.14
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
1 843.21
1 833.21
44.33
840.46
44.39
840.40
44.50
840.29
44.52
840.27
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: TWL
Page 1 of 1

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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
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Science & Engineering Consultants

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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)
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Science & Engineering Consultants

Groundwater Conditions Quarterly Report — January 2024 to March 2024
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
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Groundwater Conditions Quarterly Report — January 2024 to March 2024
Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1
Terrell, North Carolina
APPENDIX D
MANN-KENDALL DATA
INCLUDED AS EXCEL FILE)
L7
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Science & Engineering Consultants