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Home My WebLink About1812_DukeMarshall_2023Q3_GWCR_FID1820074_20231031(� DUKE ENERGY October 31, 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 — July 2023 through September 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 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 July 2023 through September 2023 (Q3 2023). The quarterly report includes an analysis of groundwater levels and dewatering pump flowrates within Phases 2, 3 and 4, with an updated water level map, 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 (Q4 2023) will be submitted by February 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 (717) 982-0986. Respectfully submitted, j4VAi Ashley Healy, P.G. Environmental Services Attachments: Industrial Landfill No.1 (1812-INDUS-2008) Groundwater Conditions Quarterly Report — July 2023 through September 2023 (SynTerra; October 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 Tyler Hardin, Duke Energy Ed Sullivan, Duke Energy Thomas Colton, SynTerra Craig Eady, SynTerra www.duke-energy.com Page 2 of 2 L1 synTerra Science & Engineering Consultants synterracorp.com GROUNDWATER CONDITIONS QUARTERLY REPORT - JULY 2023 TO SEPTEMBER 2023 INDUSTRIAL LANDFILL NO. 1 (1812-INDUS-2008) FOR MARSHALL STEAM STATION 8320 EAST CAROLINA HIGHWAY 150 TERRELL, NC 28682 OCTOBER 31, 2023 PREPARED FOR L7 DUKE Z ENERGY DUKE ENERGY CAROLINAS, LLC C 1g Eady, NC LG 41599 ��+++++""hUrgq� Key,' 'Reilly Senior Peer Reviewer ,�``�t� Pr ect Sc" ntist �'��oEESS1pN'y9 �� SEAL 056667 THOMAS,�co', Gordon Thomas Colton, NC PE #056667 rn+,I+++ Associate Engineer Groundwater Conditions Quarterly Report — July 2023 to September 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.......................................................2-1 2.3 Dewatering and Underdrain Pump Performance.......................................................2-3 3.0 QUARTERLY WATER -LEVEL REDUCTION ACTIVITIES.................................................... 3-1 4.0 REFERENCES...............................................................................................................4-1 October 2023 Page i Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 (September 2023) Figure 3A Background Monitoring Well Hydrographs (GWA-4S/D and MW-4/D) Figure 313 Perimeter Hydrographs (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 Phase 3 Hydrographs (CLF22-305 and CLF22-306) Figure 31 Within and South of Phase 4 Hydrographs (CLF22-307 and CLF23-405) Figure 3J Future Phase 4 and 5 Hydrographs (CLF23-406 and CLF23-407) Figure 3K 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 October 2023 Page ii Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 ILF NCDEQ NPDES reporting period Site gallons per minute Industrial Landfill 1812-INDUS-2008 North Carolina Department of Environmental Quality National Pollutant Discharge Elimination System third quarter 2023 (July 2023 to September 2023) Marshall Steam Station October 2023 Page Hi Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 (FID 1609547). Data collected during the third quarter of 2023 (July 2023 to September 2023) reporting period were used to evaluate groundwater conditions for the ILF Phase 2 expansion (includes Cell 5 and Cell 6) and ILF Future Phases 3, 4, and 5 expansion (Future Phases). Specifically, this report evaluates the groundwater levels, 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 are generally stable or decreasing. • Water levels have been maintained at less than or approximately equal to modeled predictions in most areas, with the exception of thirteen locations (CLF-305, CLF-306, CLF-307, CLF-401, CLF-402, CLF21-13R, CLF21-14, GWA-4D, ILF-2D, CLF23-405, CLF23- 406, CLF23-407, CLF23-408). However, during the reporting period, these water levels were either decreasing or 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 25 months with an average pumping rate of 9 gallons per minute (gpm). The Future Phases dewatering pumped at an average flow rate of 119.1 gpm during July until the pump was moved in July 2023 to a new downstream location to support ash basin closure. 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 extended the period needed to operate the underdrain. October 2023 Page 1-1 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 September 27, 2023, for the upper (shallow) flow zone and were used to generate a groundwater level map (Figure 2). Site -wide water level sweeps occur semiannually during the second and fourth quarter. Observed groundwater levels during this reporting period indicate: • Groundwater is generally flowing north to south through the ILF area (Figure 2). • Some groundwater levels within and near the ILF have decreased slightly, relative to groundwater levels from Quarter 2, 2023. However, most of the groundwater levels near the ILF remain relatively similar in elevation to that of Quarter 2, 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 September 2023 (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 September 2023 were evaluated using Mann -Kendall analysis to determine water -level trends. Statistically significant decreasing trends were observed in 21 of 26 locations. Stable trends were observed at two locations (CLF21-13R and CLF23-407). Increasing trends were observed at CLF-UD, CLF21-12, and CLF21-14, however none of these locations had increasing trends during the reporting period. • Generally, decreasing or stable trends were observed in locations downgradient of the Future Phases area during the reporting period (July 2023 through September 2023) and decreasing trends for the overall reporting period (July 2021 through September 2023). 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 October 2023 Page 2-1 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 2023 Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1 Terrell, North Carolina 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 and showed decreasing trends during the reporting period (Figures 3A and 3C). ILF-2S/D are located north of the ILF (Figure 1). The shallow and deep flow zones water levels have an overall decreasing trend and show decreasing trends during the reporting period (Figure 313). • MW-4/D are located east of the ILF Phase 2 expansion (Figure 1). The shallow and deep flow zone water levels at those locations have overall decreasing trends. MW-4 shows a significantly decreasing trend over the reporting period whereas MW-41D is stable during the reporting period (Figure 3A). 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 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 show an overall decreasing trend but displays a general increasing trend during the reporting period. Water levels in CLF21-12 show an increasing trend overall since completion of the Cell 5 construction and remains stable during the reporting period. CLF21-13R water levels are overall stable but have significantly decreased during the reporting period (Figures 3C, 313, 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 since ash excavation is complete for Cell 6, however the water levels are decreasing over the reporting period. CLF21-15 has a decreasing trend overall and during the reporting period (Figure 3E). October 2023 Page 2-2 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 and CLF22-305 have an overall decreasing trend; CLF-301 has a decreasing trend during the reporting period, and CLF22-305 has decreased during the reporting period until the water level dropped below the transducer (Figures 3F and 3H). Downgradient of the Phase 2 Expansion (Future Phases Area): • Monitoring locations CLF-401 and CLF-402 are within Future Phases 4 and 5 expansion (Figure 1). Shallow water levels at CLF-401 and CLF-402 have an overall decreasing trend and were decreasing during the reporting period (Figures 3G and 3F). • Monitoring locations CLF22-306 and CLF22-307 are downgradient of the Future Phase 3 expansion (Figure 1). Shallow water levels at CLF22-306 and CLF22-307 show decreasing levels overall. Both CLF22-306 and CLF22-307 show decreasing trends during the reporting period. (Figures 3H and 31). • Monitoring locations CLF23-405, CLF23-406, CLF23-407, and CLF23-408 located in the Future Phases 3 and 4. • Overall water levels have a decreasing trend. (Figure 31, 3J, and 3K). 2.3 Dewatering and Underdrain Pump Performance A primary excavation and construction dewatering pump is located at the downgradient edge of ILF Future Phases (Figure 1). An underdrain pump is installed within the Cell 5 underdrain (CLF-UD). The dewatering pump removes ash pore water and precipitation runoff to support ash excavation, while 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 each pump is discharged to the lower portion of the ash basin where it is ultimately pumped through a water treatment system and discharged through an NPDES (National Pollutant Discharge Elimination System) outfall. The Cell 5 underdrain pumping and model -predicted dewatering rates are shown on Figure 4A. Model -predicted and measured flow rates from the Future Phases excavation dewatering pump are shown on Figure 413. The Cell 5 underdrain pump has been operational for 25 months, at an average pumping rate for the reporting period of 9 gpm. The flow rate of the Future Phases dewatering pump decreased to an average of 119 gpm (during July 2023) from an average of 177 gpm during the prior reporting period. The Future Phases pump was moved downstream within the ash basin during the reporting period, and now collects ash basin dewatering flows from a broader area than what was included in the groundwater model. Therefore, the Future Phases pumping data is not an accurate comparison to model predictions and will no longer be included in quarterly October 2023 Paee 2-3 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 2023 Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1 Terrell, North Carolina reports going forward. 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 the Cell 5 underdrain and the Future Phases dewatering area have removed approximately 4 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 12.4 gpm overall during the reporting period and monthly average flow rates of: o 13.8 gpm during July 2023 o 12.7 gpm during August 2023 o 10.6. gpm during September 2023 The Future Phases pump had an average flow rate of 119.1 gpm monthly average flow rates in early -July prior to being moved later in July 2023. October 2023 Page 2-4 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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 12.4 gpm. • Cell 5 operations continue. Cell 6 • Cell 6 operations began on October 9, 2023. Future Phases • Excavation of coal combustion residuals (CCR) in the Future Phases continued during the reporting period. • The Future Phases pump was moved downstream within the ash basin during the reporting period, and now collects ash basin dewatering flows from a broader area than what was included in the groundwater model. Therefore, the Future Phases pumping data is not an accurate comparison to model predictions and will no longer be included in quarterly reports going forward. During the period of operations within the future phases in July 2023, the pump operated at an average 119.11 gpm. • The installation of approximately 136 dewatering wells was completed during the reporting period to support the construction of the Structural Fill (CC130031) northern stability feature. The dewatering wells are phase 1 of a larger scale dewatering system that is expected to temporarily influence the groundwater elevations in the vicinity of ILF Future Phases nearest the stability feature dewatering system. Note the dewatering system to support construction of the stability feature was not included in the groundwater model simulations. October 2023 Page 3-1 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 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. October 2023 Page 4-1 Project: 00.0083.46.09 Groundwater Conditions Quarterly Report — July 2023 to September 2023 Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1 Terrell, North Carolina FIGURES L7 synTerra Science & Engineering Consultants r � ei ILF 2S/D ® ol wt - lar • U, CLIF 10 _ 920 s, • • 1 os° 910 �' - r_,' a,•x`.: r y^ iI I •V GWA-4S/D ti^ — CLF21-18 MW-4 _ •I • . - .r ■ — 850 CLF21-19 +��' 4. ` ! a. °" CLF21-11 830 c .,� • a -•ram,. r, - r , CLF21 20 , v`_ ` ;' •ftftft ►` ' CLF21-15 1 LEGEND LONG-TERM PIEZOMETER AND/OR ° GROUNDWATER MONITORING WELL 1sli'.-� .±�� ■ � . �.�a.- - - CLF21-17 � - FO ti �y CLF21-13® p a TEMPORARY PIEZOMETER - '" % �, CLF21-13R _ •jyaj•� I." ' - 1 � CLF21-14 3. ♦ � DEWATERING OR UNDERDRAIN PUMP � ABANDONED PIEZOMETER du • �' \ m1° �' ,x�i =---; ASH BASIN WASTE BOUNDARY CLF-301 a8o Bdq GEOGRAPHIC LIMITATION LANDFILL COMPLIANCE BOUNDARY Hp CLF-401----��. ' i o yfr" ; V g20 e ��_ ` �! g•� e1 ----' STRUCTURAL FILL BOUNDARY • • �, . LANDFILL BOUNDARY s LEACHATE BASIN O. DUKE ENERGY CAROLINAS PROPERTY LINE CLF-402 TOPOGRAPHIC CONTOUR 10' INTERVAL CLF-403 7 •► pe r OB 3 (MW 7) ( ) •, STREAM (MCKIM & CREED) CLF23-4o8 0 0I ® WETLAND (MCKIM & CREED) l CLF22-305 \ NOTES: •4' ;a 0 � o p d • r 1. THE CLF-UD LOCATION WAS FORMERLY KNOWN AS CELL 5 PUMP. 4 CLF22-306:• 2. ALL BOUNDARIES ARE APPROXIMATE. CLF-404 °° 3. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS APPROVED *' CLF23-405 ° ■ • ° BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2017 (SAW-2015-01412). - •` n' = _ _ '� _ 1 S WETLANDSAND STREAMS BOUNDARIES WERE OBTAINED FROM AMEC FOSTER �y � o ` WHEELER ENVIRONMENTAL AND INFRASTRUCTURE, INC. NATURAL RESOURCES V. 11>; ' :".1''� '•--.o LTy + �°NO.�' -' _ 2 TECHNICAL REPORT (NRTR) DATED JUNE 2015. ' 4. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. .. Q) FUTURE Q ' a . : 5. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD .o,+h„4PHASES PUMP '� ''= NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED 890 �` v BY TRANSASH. •a • " 6. AERIAL IMAGERY IS A COMBINATION OF DUKE ENERGY PROPELLER AERIAL CLF22-307 _ o a PHOTOGRAPHY COLLECTED ON MAY 8, 2023, AND MAXAR SATELLITE IMAGERY OBTAINED FROM ESRI ONLINE, COLLECTED ON AUGUST 23, 2021. CLF-304 7. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINASTATE PLANE COORDINATE SYSTEM FIPS 3200 (NAD83). f'DUKE 200 ORAPHICSC200 400 FIGURE 1 ENERGY MONITORING LOCATION MAP CAROLINAS DRAWN l (IN FEET) ING DATE: 04/28/2022 GROUNDWATER CONDITIONS QUARTERLY REPORT REVISED BYTLKFOREMAN DATE:110/30/2023 JULY 2023 THROUGH SEPTEMBER 2023 CHECKED BY: T. COLTON DATE: 10/30/2023 7 APPROVED BY:T.COLTON DATE:10/30/2023 MARSHALL STEAM STATION synTerrd PROJECT MANAGER: T. COLTON TERRELL NORTH CAROLINA ' www.synterracori).com PAO ARCGIS PRO PROJECTS\DUKE ENERGY\MARSHALL\2023\GW CONDITIONS QUARTERLY REPORT\GW CONDITIONS OUARTERLY REPORT 02.APRX 40000.� ♦ a �yR.ar •�e°�,! � ,yam 10000%01 P: � 401 1 F.. �pryy CLF21-10 �• �p5 ' 840.14 ■ .. 4 GWA-4S I -.-- ...... ILF2S 840.89 b.`^i _ ♦ ■ IN -940 930- ♦ �� , LEGEND ° - WELL ID 910 - - , t ' =• ` _ 76s.8o WATER LEVEL (NAVD 88, FEET) MW 4 BACKGROUND MONITORING WELL 1 . i !`� I j - -870Pft�- 828.51 MONITORING WELL a5o� C PIEZOMETER ° r.,< •�'I� •;Y � I♦ I ♦ CL0F21- 11 ` ._., . j --��-•8-2 5.C.6 t; �tV oc ° '■�' s ' ♦ .•: - ABANDONEDPIEZOMETER826.49 LF21-16 WELL ABANDONED b--♦ �� "•a225 -� 1"'. DEWATERING OR UNDERDRAIN PUMP .y. ♦/� S ../ �xN 880 00 I� 1-7 I40 i °♦ - A- --- INFERRED WATER LEVEL CONTOUR 2.5' INTERVAL ' I � CLF-UD � � CLF21-15 {. �' ( ) 823.89 � CLF21-12 � 1 �� GROUNDWATER FLOW DIRECTION FUTURE PHASES h I CLF21-17 4f , �. -� " [ " : - _ ASH BASIN WASTE BOUNDARY - J -, CLF21-13R f ,1 � � r 817108 _ =21-13 CLF21-14R GEOGRAPHIC LIMITATION ` �♦ : ♦ CLF21 14 820 2w , _ LANDFILL COMPLIANCE BOUNDARY 4f I -------815-- - o a _ y ---- CLF-301 - �` �`"� - - - STRUCTURAL FILL BOUNDARY I�i't _ a12.s -� - 812.04 LANDFILL BOUNDARY �L 810--- CLF23407�-- ♦ 1�°�--1 �� aL� 03.69 YT - 806 12 k )' \' 1 / LANDFILL CELL 5 AND 6 BOUNDARY LEACHATE BASIN DUKE ENERGY CAROLINAS PROPERTY LINE ski TOPOGRAPHIC CONTOUR (10' INTERVAL) STREAM (MCKIM &CREED) i tJ ��`+\`N\ `� xj 900 �AL-3S 0 WETLAND (MCKIM & CREED) i CLF-302 o �l . , �- `�- v �i�•%N: a � �� ♦ MW-7 (OB-3) o` NOTES: 1. WATER LEVELS WERE COLLECTED ON 9/27/2023. 797.81 (�` `~ �; ♦` ` �� ° 2.' - UNDERDRAIN/DEWATERING PUMP ELEVATION. WATER LEVEL CONTROL POINT. CLF22-305 3. "- FUTURE PHASES PUMP LOCATION IS FOR REFERENCE ONLY. NOTA WATER jo `2 • o:,��"-...a �.� 800.62 1 LEVEL CONTROL POINT. ? 4. ELEVATIONS ARE REFERENCED TO THE NORTH AMERICAN VERTICAL DATUM OF N, \i CLF22-306 ,f 1988 (NAVD 88). )1 CLF-404 797.63 J w� 5. THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION WAS 'k, L CLF-303 o APPROVED BY THE US ARMY CORPS OF ENGINEERS ON OCTOBER 25, 2017 CLF23-405)--�` (SAW-2015-01412). WETLANDS AND STREAMS BOUNDARIES WERE OBTAINED FROM PVS= aJ )a 797.92 �9� 5'� AMEC FOSTER WHEELER ENVIRONMENTAL AND INFRASTRUCTURE, INC. NATURAL C,. - a RESOURCES TECHNICAL REPORT (NRTR) DATED JUNE 2015. 1' AB-15S _ •�. 6. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD �, NOT BE USED FOR DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY PROVIDED BY TRANSASH. R.QD B V AB-15SL r' -�o FUTURE , 7. PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. CLF22-307 PHASES PUMP J .AL-2S S.ALL BOUNDARIES ARE APPROXIMATE. ` $r" r ''t 796.60 "O 9. AERIAL IMAGERY IS A COMBINATION OF DUKE ENERGY PROPELLER AERIAL N a / PHOTOGRAPHY COLLECTED ON MAY 8, 2023, AND MAXAR SATELLITE IMAGERY -�°'b'• - ; S - CLF-304 • e o ° C OBTAINED FROM ESRI ONLINE, COLLECTED ON AUGUST 23, 2021. -:®-�+, , t",`z�• • f�• - p° e - 10. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200 (NAD83). GRAPHIC SCALE ,. 84o > -c+ Cr DUKE 200 0 200 400 FIGURE 2 �C> ENERGY (IN FEET) AREA OF FOCUS WATER -LEVEL MAP '>... v CAROLINAS UPPER FLOW ZONE SEPTEMBER 2023 •• _T.•."- •�-,r'..�•- DRAWN BY: T. KING DATE: 05/12/2022 GROUNDWATER CONDITIONS QUARTERLY REPORT - • � REVISED BY: L. FOREMAN DATE: 10/30/2023 CHECKED BY: T. COLTON DATE: 10/30/2023 JULY 2023 THROUGH SEPTEMBER 2023 APPROVED BY: T.COLTON DATE:10/30/2023 MARSHALL STEAM STATION synTerra PROJECT MANAGER: T COLTON TERRELL, NORTH CAROLINA www.synterracorl).com P:\0 ARCGIS PRO PROJECTS\DUKE ENERGY\MARSHALL\2023\GW CONDITIONS OUARTERLY REPORT\GW CONDITIONS OUARTERLY REPORT 02.APRX Lr -_•805. ' �-�. GWA-04S/D MW-04/D 852 4 833 4 851 00 832 I •.O 00 O 3 00 .4 3 a 850 a 831 O z v oo o ♦ z v �♦ c 849 � 2 c 830 2 ♦ M > iE > c u, 848 — O O p °c uw 829 I 00�1 J p J O. 1 v 847 ♦ °�{ 828 I I I l 846 0 827 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date Date GWA-04S - Total water level change from transducer installation on 07/30/2021 to 07/26/2023 is -3.5 feet. MW-04 - Total water level change from transducer installation on 07/30/2021 to 09/26/2023 is -3.9 feet. GWA-04D - Total water level change from transducer installation on 07/30/2021 to 07/26/2023 is -4.2 feet. MW-04D - Total water level change from transducer installation on 07/30/2021 to 09/26/2023 is -4.3 feet. GWA-04S/D MW-04/D 837 855 00 00 0 852 p p a 834 a o z z I U. 0 0 to --------�� m849 Op �� 831 :;oo � Uj O O a> i O O _ w I p O > O D a�i J 846 O O v m 828 825 843 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date Date LEGEND Notes: Cell 5 construction start (05/31/2021) NAVD 88 —North American Vertical � DUKE DRAWN BY: D. AVARD DATE: 07/21/2021 FIGURE 3A BACKGROUND MONTIORING WELL HYDROGRAPHS— Future Phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 ENERGY.. REVISED BY: D. AVARD DATE: 10/09/2023 INDUSTRIAL LANDFILL NO 1. Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet RQl INAS CHECKED BY: T. COLTON DATE: 10/11/2023 (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction completion (10/22/2021) in - inches APPROVED BY:T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT Shallow Groundwater Flow Zone (Transducer Data) 110, JULY 2023 THROUGH SEPTEMBER 2023 Deep Groundwater Flow Zone (Transducer Data) ♦ Manual Water Level Measurement PROJECT MANAGER: T. COLTON MARSHALL STEAM STATION Bedrock Groundwater Flow Zone (Transducer Data) Daily Total Rainfall (inches) �T a TE N TERRELL, NORTH CAROLINA — — - Transient Groundwater Model Water Level Predicted Trend www.synterracorp.com 00 0 a z c 0 41 M LLI a� d J N M ILF-02S/D 846 - 845 - 844 - 843 - 842 - 841 - 840 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date ILF-02S - Total water level change from transducer installation on 07/30/2021 to 06/28/2023 is -0.8 feet. ILF-02D - Total water level change from transducer installation on 07/30/2021 to 06/28/2023 is -1.3 feet. ILF-02S/D 849 - 846 - 843 - 840 - 837 6/1 /2021 ■ 1pill�� 1111F1IMP111101hI�I�IM 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date 4 3 c 2 Space Not Used 1 0 Space Not Used LEGEND Cell 5 construction start (05/31/2021) Notes: NAVD 88 — North American Vertical DUKE DRAWN BY: D. AVARD DATE:07/21/2021 FIGURE 3B PERIMETER HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1. ENERGY. REVISED BY: D. AVARD DATE: 10/09/2023 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: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) ♦ Manual Water Level Measurement PROJECT MANAGER: T. COLTON MARSHALL STEAM STATION Deep Groundwater Flow Zone (Transducer Data) — — - Transient Groundwater Model Water Level Predicted Trend Daily Total Rainfall (inches) synTerra TERRELL, NORTH CAROLINA www.synterracorp.com CLF21-10 CLF21-11 843 842 00 a a 841 z LPL c 840 O M a� �iD2•J v J L 838 M Mo * 4> *0*111111l � 4 3 KA 1 837 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF21-10 - Total water level change from transducer installation on 08/10/2021 to 09/26/2023 is -0.9 feet. a 00 842 a z Lj- c 840 41 M a� LJJ GJ > 838 v r M 836 -L1-- 6/1 /2021 CLF21-10 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date C 4- c 00 a z LL C O co _O W a� a� J L a1 m - sE 832 830 828 826 824 822 M 3 1 820 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF21-11- Total water level change from transducer installation on 08/09/2021 to 09/26/2023 is -4.0 feet. CLF21-11 834 831 828 825 822 -L+-- 6/1 /2021 \ \ \ 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date LEGEND Notes: t DUKE DRAWN BY: D.AVARD DATE:07/21/2021 FIGURE 3C Cell 5 construction start (05/31/2021) NAVD 88 - North American Vertical ENERGY.; REVISED BY: D. AVARD DATE: 10/09/2023 NORTHWEST OF CELL 5 HYDROGRAPHS - INDUSTRIAL LANDFILL NO 1. Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 RQl INAS (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet CHECKED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT `� Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement PROJECT MANAGER:T.COLTON MARSHALL STEAM STATION - Transient Groundwater Model water level predicted trend Daily Total Rainfall (inches) syriTeria TERRELL NORTH CAROLINA www.synterracorp.com CLF-LID CLF21-12 818 - [.,SET. 00 00 0 a z 814 +; ILL 0 > 812 2 W N > L 810 - r M Il 3 KA 1 c 4- c 808 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF-UD— Water level is stable during underdrain operations. Water levels spikes represent when pump was temporarily out of service. CLF-UD 819 r� p 816 a z 41 Lj- c 41 813 M > GJ W W > GJ 810 v r M 807 -L1-- 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date - 824 823 822 821 820 819 818 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF21-12 - Total water level change from transducer installation on 08/09/2021 to 09/26/2023 is -2.7 feet. CLF21-12 825 OD O 00 I 0 a 820 p z c 0 > 815 a� W N > I N J L 810 I sE 805 '1 L 6/1 /2021 12/1 /2021 6/1 /2022 Date O o 12/1/2022 6/1/2023 4 3 c 2 1 0 c of6c 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: 10/09/2023 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: 10/11/2023 1812-INDUS PHASE 2 EXPANSION ( � Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY:T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT Shallow Groundwater Flow Zone (Transducer Data) `,� PROJECT MANAGER: T. COLTON JULY 2023 THROUGH SEPTEMBER 2023 - Transient Groundwater Model water level predicted trend Manual Water Level Measurement MARSHALL STEAM STATION Daily Total Rainfall (inches) �Ta www.synterracorp.com TERRELL NORTH CAROLINA CLF21-14/R CLF21-15 823 - 822 - 00 a821 z ILL c 820 O M N > aj J L 818 - M r III ' III 11101111 4 3 KA 1 817- 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF21-14R - Total water level change from transducer installation on 04/08/2022 to 09/26/2023 is +1.9 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 r� a 00 825 a z ILL 41 820 M > GJ W 810 -LIl-- 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date c - sE 828 825 822 819 816 t c 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF21-15 - Total water level change from transducer installation on 08/13/2021 to 03/30/2023 is -3.5 feet. The CLF21-15 transducer was removed in April 2023. The transducer was re -installed in July 2023. Total water level change from transducer installation on 07/31/2023 to 09/26/2023 is +0.3 feet. CLF21-15 828 825 822 819 816 -L -- 6/1 /2021 .7 0 0 o 00 � �O p00 O O O 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date LEGEND Cell 5 construction start (05/31/2021) Notes: NAVD 88 - North American Vertical DUKE DRAWN BY: D.AVARD DATE:07/21/2021 FIGURE 3E EAST OF CELL 6 HYDROGRAPHS - INDUSTRIAL LANDFILL NO 1. ENERGY. REVISED BY: D. AVARD DATE: 10/09/2023 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: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT `� Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement PROJECT MANAGER:T.COLTON MARSHALL STEAM STATION - Transient Groundwater Model water level predicted trend p Daily Total Rainfall (inches) �1��..i ery � TERRELL NORTH CAROLINA www.synterracorp.com CLF-301 CLF-402 819 - 00 817 0 a z 41Lj- c 815 M a� W N a>i 813 - J L M i� �I i 1 711 7il 811 6/1 /2021 10/1 /2021 2/1 /2022 6/1/2022 10/1 /2022 2/1 /2023 6/1/2023 Date CLF-301- Total water level change from transducer installation on 07/27/2021 to 09/26/2023 is -4.4 feet. CLF-301 819 0 816 a z c 813 M > GJ W (IJ > GJ 810 v r m 807 -L+--- 6/1 /2021 0 0 00 0 � � o O 12/1/2021 6/1/2022 12/1/2022 6/1/2023 Date 0 3 KA 1 0 c i sE 814 811 - ! 805 g0 •O 00 0 O 802 6/1 /2021 10/1 /2021 2/1 /2022 6/1/2022 10/1 /2022 2/1 /2023 6/1/2023 Date CLF-402 - Total water level change from transducer installation on 07/27/2021 to 09/26/2023 is -8.9 feet. CLF-402 815 810 805 F-011111 795 6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 Date 3 KA 1 0 c LEGEND Notes: t DUKE DRAWN BY: D.AVARD DATE:07/21/2021 FIGURE 3F Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical ENERGY.; REVISED BY: D. AVARD DATE: 10/09/2023 FUTURE PHASE 3 AND 4 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1. Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 RQl INAS (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet CHECKED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT `� Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement PROJECT MANAGER:T.COLTON MARSHALL STEAM STATION - Transient Groundwater Model water level predicted trend Daily Total Rainfall (inches) syriTeria TERRELL NORTH CAROLINA www.synterracorp.com CLF21-13/R 822 820 00 a818 z LL c 816 0 M u' 814 G1 ai 812 M 810 4 3 2 1 0 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF21-13R - Total water level change from transducer installation on 11/08/2021 to 09/26/2023 is -1.1 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 0 820 a z 815 M > GJ W W > 810 M SNovember CLF21-13 was abandoned and replaced on 4, 2021. ♦ O II 1 III I II 805 -L+--- 6/1 /2021 O O O O 12/1/2021 6/1/2022 12/1/2022 6/1/2023 Date 818 00 815 a z 4j LL c 812 0 a� W Gl a>, 809 J Gl m 806 sE CLF-401 0 0♦ 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF-401- Total water level change from transducer installation on 07/27/2021 to 09/26/2023 is -8.5 feet. CLF-401 820 815 E-511 t 805 E-1911M 795 ' 1 L 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date 4 3 KA 1 0 C LEGEND Cell 5 05/31/2021 Notes: DUKE DRAWN BY: D. AVARD DATE:07/21/2021 FIGURE 3G CELL 5 AND FUTURE PHASE 5 HYDROGRAPHS— construction start ( ) NAVD 88 —North American Vertical ENERGY REVISED BY: D. AVARD DATE: 10/09/2023 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: 10/11/2023 (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT Shallow Groundwater Flow Zone (Transducer Data) `,� PROJECT MANAGER: T. COLTON JULY 2023 THROUGH SEPTEMBER 2023 - Transient Groundwater Model water level predicted trend Manual Water Level Measurement MARSHALL STEAM STATION Daily Total Rainfall (inches) �Ta www.synterracorp.com TERRELL NORTH CAROLINA CLF22-305 CLF22-306 00 00 0 a z LPL C 0 41 M a� W N > J L M 812 - E:TiEc1♦ 799 792 CLF22-305 water level dropped below the transducer as noted by manual water level recordings starting 8/8/2023. O O �I ♦ ILI 1'llll �LaL Date CLF22-305 - Total water level change from transducer installation on 08/10/2021 to 09/26/2023 is -8.3 feet. CLF22-305 0 3 ICI 1 0 C 4- c 785 -4— '. r T T 1 1 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF22-305 was not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of CLF22-305 (after Transient Groundwater Model calibration) LEGEND Notes: DUKE Cell 5 construction start (05/31/2021) NAVD 88 — North American Vertical ENERGY. Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 CAROLINAS 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) 110 -Transient Groundwater Model water level predicted trend � Manual Water Level Measurement Daily Total Rainfall (inches) synTerra i sE 807 804 801 798 -d L j . . . . . . . . 'A 795 6/1 /2021 10/1 /2021 2/1 /2022 6/1 /2022 10/1 /2022 2/1 /2023 6/1 /2023 Date CLF22-306 - Total water level change from transducer installation on 08/13/2021 to 09/26/2023 is -4.9 feet. CLF22-306 :M 792 784 776 3 1 0 6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 Date CLF22-306 was not used in the Transient Groundwater Model calibration, water level predictions were prepared following installation of CLF22-306 (after Transient Groundwater Model calibration) DRAWN BY: D. AVARD DATE: 07/21/2021 FIGURE 3H REVISED BY: D. AVARD DATE: 10/09/2023 PHASE 3 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1. CHECKED BY: T. COLTON DATE: 10/11/2023 (1812-INDUS) PHASE 2 EXPANSION GROUNDWATER CONDITIONS QUARTERLY REPORT APPROVED BY: T. COLTON DATE: 10/11/2023 DULY 2023 THROUGH SEPTEMBER 2023 PROJECT MANAGER: T. COLTON MARSHALL STEAM STATION www.synterracorp.com TERRELL, NORTH CAROLINA CLF22-307 CLF23-405 807 - 00 804 0 a z ILL c 801 0 41 M a� W N a>i 798 - 4-1 GJ M 1� 4 3 KA 1 795 0 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF22-307 - Total water level change from transducer installation on 04/08/2022 to 09/26/2023 is -6.2 feet. CLF22-307 810 p 800 a z 0 790 M > GJ W N > GJ 780 N M c 4- c i 807 804 801 798 4 3 1 795 0 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF23-405 - Total water level change from transducer installation on 03/01/2023 to 09/26/2023 is -6.7 feet. CLF23-405 812 804 796 788 770 -L+-- 1. r T T 1 1780 'i ' - 1. 1- 6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 6/1/2021 12/1/2021 Date 6/1/2022 12/1/2022 6/1/2023 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: t DUKE DRAWN BY: D.AVARD DATE:07/21/2021 FIGURE 31 Cell 5 construction start 05/31/2021 ( ) NAVD 88 —North American Vertical ENERGY REVISED BY: D. AVARD DATE: 10/09/2023 WITHIN AND SOUTH OF PHASE 4 HYDROGRAPHS Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 INDUSTRIAL LANDFILL NO 1. - (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction start (9/20/2021) Ft - Feet CAROLINAS CHECKED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT Cell 5 Blanket Underdrain construction completion (10/22/2021) in - inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) � Manual Water Level Measurement PROJECT MANAGER: T. COLTON MARSHALL STEAM STATION -Transient Groundwater Model water level predicted trend Daily Total Rainfall (inches) WnTerra TERRELL, NORTH CAROLINA www.synterracorp.com CLF23-406 CLF23-407 810 00 807 0 a z 41 Lj- c 804 0 .41 v W N a, 801 J L M 798 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF23-406 - Total water level change from transducer installation on 03/01/2023 to 09/26/2023 is -9.7 feet. CLF23-406 818 a 00 810 a z LL c 0 802 ++ M > GJ W N > OJ 794 a� r m 4 3 KA 1 0 c i sE 812 810 804 6/1 /2021 12/1 /2021 6/1/2022 12/1 /2022 6/1 /2023 Date CLF23-407 - Total water level change from transducer installation on 03/01/2023 to 09/26/2023 is -2.5 feet. CLF23-407 818 812 :I. 786 -4- '. 1 T T 1 1794 'i ' - '. 1 6/1/2021 12/1/2021 6/1/2022 12/1/2022 6/1/2023 6/1/2021 12/1/2021 Date �o 0 6/1/2022 12/1/2022 6/1/2023 Date M 3 1 0 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: t DUKE DRAWN BY: D.AVARD DATE:07/21/2021 FIGURE 3.1 Cell 5 construction start 05/31/2021 ( ) NAVD 88 -North American Vertical ENERGY REVISED BY: D. AVARD DATE: 10/09/2023 FUTURE PHASE 4 AND 5 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: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT �� Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement PROJECT MANAGER:T.COLTON MARSHALL STEAM STATION - Transient Groundwater Model water level predicted trend Daily Total Rainfall (inches) T�.pi ery �r— � TERRELL ' NORTH CAROLINA www.synterracorp.com CLF23-408 807 - 00 804 f7 a z ILL c 801 0 41 M a� W N a>i 798 - 4-1 41 M i 0 3 KA 1 795 0 6/1 /2021 12/1 /2021 6/1 /2022 12/1 /2022 6/1 /2023 Date CLF23-408 - Total water level change from transducer installation on 03/21/2023 to 09/26/2023 is -5.9 feet. CLF23-408 812 a 00 805 > Q z a+ U- r- 0 798 +j M a1 W N > O1 791 a� r m 784 -L+--- 6/1 /2021 <3 12/1/2021 6/1/2022 12/1/2022 6/1/2023 Date c 4- c Space Not Used Space Not Used 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 WITHIN PHASE 4 HYDROGRAPHS — INDUSTRIAL LANDFILL NO 1. ENERGY. REVISED BY: D. AVARD DATE: 10/09/2023 Future phases 3 through 5 CCR excavation start (06/18/2021) Datum 1988 CARC]LINAS (1812-INDUS) PHASE 2 EXPANSION Cell 5 Blanket Underdrain construction start (9/20/2021) Ft -Feet CHECKED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT `� Cell 5 Blanket Underdrain construction completion (10/22/2021) in -inches APPROVED BY: T. COLTON DATE: 10/11/2023 JULY 2023 THROUGH SEPTEMBER 2023 Shallow Groundwater Flow Zone (Transducer Data) Manual Water Level Measurement PROJECT MANAGER:T.COLTON MARSHALL STEAM STATION - Transient Groundwater Model water level predicted trend p Daily Total Rainfall (inches) �1��..i ery � TERRELL ' NORTH CAROLINA www.synterracorp.com 0- W a� co oc O U- .ru N S✓ Ln N U 140 120 100 E1 FA ❑1 3 2 1 I 9/1/2021 3/1/2022 9/1/2022 3/1/2023 9/1/2023 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: 10/09/2023 DATE: 10/11/2023 CELL 5 (UNDERDRAIN) PUMPING FLOW RATE VS. SIMULATED FLOW RATE APPROVED BY: T. COLTON DATE: 10/11/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT 46� PROJECT MANAGER: T. COLTON JULY 2023 THROUGH SEPTEMBER 2023 synTerra MARSHALL STEAM STATION TERRELL, NORTH CAROLINA www.synterracorp.com 500 A CL a0 (D 300 ca DC 0 IL 200 Ln W cN ca 100 4 LL 0 i -- - - 9/1/2021 12/1/2021 3/1/2022 6/1/2022 9/1/2022 12/1/2022 3/1/2023 6/1/2023 X Actual Pumping Flow Rate (gpm) Years of Operation ■ Model Flow Rate (gpm) Notes: Rainfall Daily Total (in) 1. gpm = gallons per minute. 2. Flow data from the first day following a period of no flow were not plotted. 3. Data through 7/15/2023 3 2 Ln U 0 1 � �U v 0 DUKE DRAWN BY: T. COLTON DATE: 10/13/2021 FIGURE 413 4 ENERGY REVISED BY: D. AVARD DATE: 10/23/2023 c CHECKED BY: T. COLTON DATE: 10/23/2023 PHASE 3-5 PUMPING FLOW RATE VS. SIMULATED FLOW RATE APPROVED BY: T. COLTON DATE: 10/23/2023 GROUNDWATER CONDITIONS QUARTERLY REPORT 4610 PROJECT MANAGER: T. COLTON JULY 2023 THROUGH SEPTEMBER 2023 MARSHALL STEAM STATION synTena www.synterracorp.com TERRELL, NORTH CAROLINA Groundwater Conditions Quarterly Report — July 2023 to September 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 JULY 2023 THROUGH SEPTEMBER 2023 MARSHALL STEAM STATION DUKE ENERGY CAROLINAS, LLC, TERRELL, NC Well ID Date Well/ Piezometer Installed Date Transducer Installed Monitoring Zone Northing (Ft-NAD 83) Easting (Ft-NAD 83) Measuring Point TOC Elevation (Ft-NAVD 88) Ground Surface Elevation (Ft-NAVD 88) Total Well Depth 2,3 (Ft-BGS) Measured Well Depth' (Ft-TOC) Screened Interval 3 (Ft TOC) Top of Screen Elevation (Ft-NAVD 88) Bottom of Screen Elevation (Ft-NAVD 88) Water Level Measurement (Ft-TOC) 08/08/2023 Groundwater Elevation (Ft-NAVD 88) 08/08/2023 Water Level Measurement (Ft-TOC) 09/07/2023 Groundwater Elevation (Ft-NAVD 88) 09/07/2023 Water Level Measurement (Ft-TOC) 9/27/2023 Groundwater Elevation (Ft-NAVD 88) 9/27/2023 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 34.89 812.57 35.21 812.25 35.42 812.04 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 Abandoned Abandoned Abandoned 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 Abandoned Abandoned Abandoned CLF-401 5/17/2021 7/27/2021 Shallow 685783.50 1412779.50 832.44 830.44 39.00 41.00 29.00 39.00 803.44 793.44 24.55 807.89 25.19 807.25 25.65 806.79 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 14.13 804.28 15.00 803.41 15.55 802.86 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 17.27 840.48 17.38 840.37 17.61 840.14 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 23.73 826.44 23.75 826.42 23.68 826.49 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 18.46 820.60 Inaccessible 18.76 820.30 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 17.60 818.61 Inaccessible 19.13 817.08 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 26.70 820.84 26.97 1 820.57 27.27 820.27 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 Inaccessible Inaccessible 40.48 823.89 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 17.78 801.43 18.61 800.60 18.59 800.62 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 16.96 799.40 18.03 798.33 18.73 797.63 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 27.52 798.44 28.58 797.38 29.36 796.60 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 10.75 799.54 11.84 798.45 12.37 797.92 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 13.50 800.46 14.80 799.16 14.85 799.11 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 21.61 807.26 44.18 784.69 22.75 806.12 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 11.60 799.21 12.63 798.18 13.00 797.81 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 54.15 848.30 54.35 848.10 54.54 847.91 GWA-4S 5/19/2015 7/30/2021 Shallow 686776.57 1411777.34 901.97 898.98 67.99 70.98 52.19 67.19 849.78 834.78 54.43 847.54 54.48 847.49 54.66 847.31 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 NM NM 38.61 828.54 38.64 828.51 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 38.80 827.94 38.94 827.80 39.06 827.68 MW-7 (OB 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 Abandoned Abandoned Abandoned ILF-21) 3/31/2019 7/30/2021 Deep 687699.24 1413205.78 885.14 885.57 107.00 106.57 91.57 101.57 793.57 783.57 41.23 843.91 41.27 843.87 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 1 51.58 843.21 833.21 43.65 841.14 43.76 841.03 43.90 840.89 Notes: ' Well depths initially measured during well installation and updated as new wells are installed. z "Total Well Depth" is the depth to the bottom of the filter pack. 3 Values measured during well installation BGS - Below ground surface TOC - Top of casing Ft - Feet NAD 83 - North American Datum of 1983 NAVD 88 - North American Vertical Datum of 1988 NM - Not measured Prepared by: GTC Checked by: DAA Page 1 of 1 Groundwater Conditions Quarterly Report — July 2023 to September 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 — July 2023 to September 2023 Duke Energy Carolinas, LLC - Marshall Steam Station - Industrial Landfill No. 1 Terrell, North Carolina APPENDIX B GROUNDWATER MODEL PREDICTED TREND FILES INCLUDED AS EXCEL FILE) L7 synTerra Science & Engineering Consultants Groundwater Conditions Quarterly Report — July 2023 to September 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 — July 2023 to September 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