NC0005088_CSS_Appendix G_20191231

Corrective Action Plan Update December 2019
Cliffside Steam Station
APPENDIX G
SynTerra
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT

UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
FOR
CLIFFSIDE STEAM STATION,
MOORESBORO, NORTH CAROLINA
DECEMBER 2019
PREPARED FOR
r� DUDE
ENERGY®
CAROLINAS
DUKE ENERGY CAROLINAS� LLC
INVESTIGATORS
REGINA GRAZIANO, M.S. - SYNTERRA CORPORATION
RONALD W. FALTA, PH.D. - FALTA ENVIRONMENTAL, LLC
YOEL GEBRAI, M.S. - SYNTERRA CORPORATION
LAWRENCE C. MURDOCH, PH.D. - FRx, INC.
RONG YU, PH. D. - SYNTERRA CORPORATION
JONATHAN EBENHACK, M.S. - SYNTERRA CORPORATION

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
EXECUTIVE SUMMARY
This groundwater flow and transport model report provides basic model development
information and simulations of basin closure designs as well as results of corrective
action simulations for the Rogers Energy Complex — Cliffside Steam Station (Cliffside,
CSS, or Site). The Site is owned by and operated by Duke Energy Carolinas, LLC (Duke
Energy) and is located in Mooresboro, Rutherford and Cleveland counties, North
Carolina. Model simulations were developed using flow and transport models
MODFLOW and MT3DMS. Due to historical ash management and wastewater
discharge activities at the Site, a numerical model was developed to evaluate transport
of inorganic constituents of interest (COIs) in the groundwater downgradient of the ash
basins. Numerical simulations of groundwater flow and transport have been calibrated
to pre -decanting conditions and used to evaluate different scenarios being considered
as options for closure of the ash basins. The simulations were also used to design a
corrective action system that would achieve compliance with North Carolina
Administrative Code, Title 15A, Subchapter 02L, Groundwater Classification and
Standards (02L) by the end of year 2026 or end of year 2029. This model and report is an
update of a previous model developed by SynTerra in conjunction with Falta
Environmental, LLC and Frx Partners (SynTerra, 2018b).
Commercial operations began at the Site in 1940 with the activation of Units 1, 2, 3, and
4 (198 MW total). Operation of Unit 5 (556 MW) began in 1972. Construction of Unit 6
(an 825 MW clean -coal unit) began in 2008. Commercial operation of Unit 6 began in
2012. Units 1 through 4 were retired from service in October 2011. Natural gas
infrastructure was completed to co -fire as much as 40 percent natural gas on Unit 5 and
as much as 100 percent on Unit 6. The first fire for natural gas at Unit 5 occurred in
October 2018 and the first fire for natural gas at Unit 6 occurred in November 2018. CSS
is a coal-fired and natural gas -fired electricity -generating facility with a combined
capacity of 1,381 megawatts (MW).
Coal combustion residuals (CCRs) were hydraulically sluiced to the active ash basin
(AAB) until 2018. The operation of Unit 5 and Unit 6 continues with dry bottom ash and
dry fly ash handling. The ash is disposed on -Site at the Coal Combustion Products
(CCP) Landfill. The AAB has been operated under a National Pollution Discharge
Elimination System (NPDES) permit issued by the North Carolina Department of
Environmental Quality (NCDEQ) Division of Water Resources (DWR) since the AAB
became operational. Previously, the former Units 1-4 ash basin (U14 AB) and the Unit 5
inactive ash basin (U5 AB) were covered by NPDES permits. Inorganic compounds in
the wastewater and ash have dissolved and have migrated in groundwater
downgradient of the ash basins.
Page i

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
The predictive simulations presented herein related to closure and corrective action are
not intended to represent final detailed closure or corrective action designs. These
simulations use closure designs developed by AECOM and Wood Inc. and are subject
to change as the closure plans are finalized (AECOM 2019 and Wood 2019). The
simulations are intended to show the key characteristics of groundwater flow and
mobile constituent transport that are expected to result from the closure actions and
corrective actions. Completion dates for each of the closure options in the groundwater
simulations are based on estimates provided by AECOM. As closure activities proceed,
these dates are subject to change. Based on preliminary modeling (SynTerra, 2018b),
variance in the start dates and completion dates of the closure does not produce
significant changes in the results of the simulations.
Boron, sulfate, and total dissolved solids (TDS) were the COIs selected to evaluate
performance of the closure designs and groundwater corrective action. These
constituents are present beyond the compliance boundary and exhibit plume
characteristics. These COIs are relatively unreactive with subsurface solids and are
readily transported and therefore are a reasonable indicator of the maximum extent of
COIs transported in groundwater derived from the ash basins or ash storage area
(ASA). Transport of less mobile constituents (i.e., arsenic, chromium, iron, manganese,
cobalt, thallium, vanadium, strontium, radium, uranium) are controlled by chemical
reactions affecting sorption and are not within the scope of this report.
This report describes refinements that have improved the accuracy and resolution of
details in the model of the CSS site since previous versions (SynTerra, 2016; SynTerra
2018). Data from recent ash pore water and saprolite pumping tests and new deep
bedrock wells near the ash basin dams were considered in this revision of the model.
Eight deep bedrock wells were recently drilled at the CSS site: one between the former
Units 1-4 ash basin (U1-4 AB) and the Broad River, two at the AAB upstream dam, three
along the AAB downstream dam, and two along the Unit 5 inactive ash basin (U5 AB)
main dam during 2019. Each well was drilled to a boring depth of approximately 300
feet with the exception of one well (GWA-65BRL), which was drilled to 400 feet. Boron
was present in these deep wells, but the concentrations were detected at less than the
North Carolina groundwater standard [NCAC Title 15A, Subchapter 02L, Groundwater
Classification and Standards (02L) of 700 µg/L. The model is calibrated to reflect the
boron migration observed in these deep bedrock wells.
The model includes recent revisions to the designs of the closure scenarios developed
by AECOM Foster Wheeler (AECOM) (2019) and Wood (2019). The model includes
data from new deep bedrock wells located along the dams. The grid has been refined in
Page ii

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
some areas to improve the model calibration results. A comprehensive dataset (through
second quarter of 2019) of hydraulic heads and boron concentrations was used to
recalibrate the model.
The simulations include an evaluation of two closure scenarios, one that involves
closure -in -place and another that involves a closure -by -excavation design. Closure -in -
place involves grading and covering the ash with a low permeability cap, and closure -
by -excavation involves excavating ash and placing it in an on -Site landfill. The
remediation design modeled in these scenarios uses both extraction and clean water
infiltration to achieve compliance. Modeling results suggest that groundwater
extraction alone will not achieve compliance in a desired timeframe due the fact that a
majority of the COIs beyond the compliance boundary may be present in the vadose
zone, above the water table in the ash storage area. This occurs because the post closure
water table is substantially lower than the current water table. As the water table drops,
boron in groundwater is left in the vadose zone above the water table.
The corrective action simulations indicate that boron can be brought into compliance in
approximately five years (for closure -in -place) and eight years (for closure -by -
excavation) after implementation using the groundwater remediation approach
simulated for the AAB and ASA (Figure ES-1). The time series of boron concentrations
at one representative location downgradient of the AAB is presented in Figure ES-2.
The simulations indicate that corrective action using techniques that are readily
available and accepted in the environmental industry would reduce boron
concentrations less than the 02L standard beyond the compliance boundary. The
simulations show that 02L compliance is achieved with groundwater corrective using
either closure scenario. Without groundwater corrective action the model simulations
indicate boron will remain greater than 700 ug/1 for several centuries. These long times
are controlled by COIs within the vadose zone and the slow transport under hydrologic
conditions following closure. However, corrective actions using groundwater extraction
and clean water infiltration can recover COIs and shorten the time required to reach
compliance to approximately one decade after implementing corrective action.
The model simulations indicate that there are no exposure pathways associated with the
groundwater flow through the ash basins and the water supply wells used for water
supply in the vicinity of CSS. Water supply wells are outside, or upgradient of, the
groundwater flow system that contains the ash basins and ASA. Groundwater
migration of constituents from the ash basins and ASA does not affect water supply
wells under pre -decanting conditions or pre -closure conditions, or in the future under
the different closure options simulated.
Page iii

CLOSURE -BY -EXCAVATION AFTER 8 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
♦ T ♦AA AAAAAA
CLOSURE -BY -EXCAVATION AFTER 179 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
i
A'♦ll
r ♦ - ♦♦
1� A AA
♦ ♦ 1
lAt 2kA
♦ .&r
0-
AA ,..♦,-
LEGEND
EXTRACTION WELL • ASH STORAGE AREA
♦ CLEAN WATER ASH BASIN WASTE
INFILTRATION WELL BOUNDARY
HORIZONTAL CLEAN _ _ _ ASH BASIN COMPLIANCE
WATER INFILTRATION • BOUNDARY
WELL
BORON 700 - 4,000 ug/L
BORON > 4,000 ug/L
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED
ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
CLOSURE -IN -PLACE AFTER 5 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
CLOSURE -IN -PLACE AFTER 179 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
GRAPHIC SCALE
250 0 250 500
(IN FEET)
r 1 • •T`r�
I
DRAWN BY: R. GRAZIANO
DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER
DATE: 12/20/2019
DUKE
CHECKED BY: T.GRANT
DATE: 12/20/2019
ENERGY
APPROVED BY: T. GRANT
DATE: 12/20/2019
PROJECT MANAGER: S. SPINNER
www.svnterracorr).com
FIGURE ES-1
COMPARISON OF SIMULATED MAXIMUM BORON
CONCENTRATIONS IN ALL NON -ASH LAYERS FOR BOTH CLOSURE
SCENARIOS WITH ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

2000
J 1600
21400
r_
,2 1200
L
1000
V O0pp �}
0
U
O 600
L
O
0 400
P ON
Point 1, Maximum boron concentration in all layers
Closure -by -Excavation
Closure -in -Place
— — 02 L Std = 700 µg/ L
0 11
lJ
I
I
I
I
I_
j
C-Ir
k.0
00
0
0
0
0
L DUKE DRAWN BY: R. GRAZIANO DATE: 11/20/2019 ES-2
T� ENERGY REVISED BY: W. PRATER DATE: 12/18/2019 COMPARISON OF MAXIMUM BORON IN ALL NON -ASH MODEL LAYERS AS
NAS CHECKED BY: T. GRANT DATE: 12/18/2019 FUNCTIONS OF TIME AT REFERENCE LOCATION 1 FOR CLOSURE -BY -
APPROVED BY: T. GRANT DATE: 12/18/2019 EXCAVATION AND CLOSURE -IN -PLACE WITH ACTIVE
�� PROJECT MANAGER: S. SPINNER GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
synTerCLIFFSIDE STEAM STATION
ra www.synterracorp.com MOORESBORO, NORTH CAROLINA

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE OF CONTENTS
SECTION
PAGE
EXECUTIVE SUMMARY.................................................................................................... ES-1
1.0 Introduction..................................................................................................................1-1
1.1 General Setting and Background..........................................................................1-1
1.2 Objectives.................................................................................................................1-4
2.0 Conceptual Model........................................................................................................2-1
2.1
Aquifer System Framework..................................................................................
2-1
2.2
Groundwater Flow System....................................................................................2-1
2.3
Hydrologic Boundaries..........................................................................................
2-2
2.4
Hydraulic Boundaries............................................................................................
2-2
2.5
Sources and Sinks....................................................................................................2-2
2.6
Water Budget...........................................................................................................2-3
2.7
Modeled Constituents of Interest.........................................................................
2-3
2.8
Constituent Transport............................................................................................
2-3
3.0 Computer Model..........................................................................................................3-1
3.1 Model Selection....................................................................................................... 3-1
3.2 Model Description.................................................................................................. 3-1
4.0 Groundwater Flow and Transport Model Construction......................................4-1
4.1
Model Domain and Grid........................................................................................4-1
4.2
Hydraulic Parameters............................................................................................4-2
4.3
Flow Model Boundary Conditions.......................................................................
4-4
4.4
Flow Model Sources and Sinks.............................................................................
4-4
4.5
Flow Model Calibration Targets...........................................................................
4-6
4.6
Transport Model Parameters.................................................................................4-6
4.7
Transport Model Boundary Conditions..............................................................
4-8
4.8
Transport Model Sources and Sinks.....................................................................4-9
4.9
Transport Model Calibration Targets..................................................................4-9
5.0 Model
Calibration to pre -decanting Conditions...................................................5-1
5.1 Flow Model Calibration......................................................................................... 5-1
5.2 Flow Model Sensitivity Analysis.......................................................................... 5-4
5.3 Historical Transport Model Calibration.............................................................. 5-4
5.4 Transport Model Sensitivity Analysis................................................................. 5-6
6.0 Predictive Simulations of closure scenarios........................................................... 6-1
Page iv

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
6.1 Interim Models with Ash Basin Ponded Water Decanted (2020-2021) ........... 6-1
6.2 Interim Period During Construction (2021-2026 or 2021-2029)........................ 6-2
6.3 Closure-in-Place...................................................................................................... 6-2
6.4 Closure -in -Place with Active Remediation......................................................... 6-4
6.5 Closure-by-Excavation........................................................................................... 6-5
6.6 Closure -by -Excavation with Active Remediation.............................................. 6-6
6.7 Conclusions..............................................................................................................6-6
7.0 References......................................................................................................................7-1
Page v

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF FIGURES
ES-1
Comparison of simulated maximum boron concentrations in all
non -ash layers for both closure scenarios with active groundwater
remediation
ES-2
Comparison of maximum boron in all non -ash model layers as
functions of time at reference location 1 for closure -by -excavation
and closure -in -place with active groundwater remediation
Figure 1-1
USGS location map
Figure 4-1
Numerical model domain
Figure 4-2
Fence diagram of the 3D hydrostratigraphic model used to
construct the model grid
Figure 4-3
Computational grid used in the model with 5x vertical
exaggeration
Figure 4-4
Hydraulic conductivity estimated from slug tests performed in
coal ash at 14 sites in North Carolina
Figure 4-5
Hydraulic conductivity estimated from slug tests performed in
saprolite at 10 Piedmont sites in North Carolina
Figure 4-6
Hydraulic conductivity estimated from slug tests performed in the
transition zone at 10 Piedmont sites in North Carolina
Figure 4-7
Hydraulic conductivity estimated from slug tests performed in
bedrock at 10 Piedmont sites in North Carolina
Figure 4-8
Distribution of recharge zones
Figure 4-9
Model surface water features
Figure 4-10
Model surface water features inside ash basin
Figure 4-11
Water supply wells in model area
Figure 5-1a
Model hydraulic conductivity zones in ash layer 1
Figure 5-1b
Model hydraulic conductivity zones in ash layer 2
Figure 5-1c
Model hydraulic conductivity zones in ash layer 3
Figure 5-1d
Model hydraulic conductivity zones in ash layer 4
Figure 5-1e
Model hydraulic conductivity zones in ash layer 5
Figure 5-1f
Model hydraulic conductivity zones in ash layer 6
Figure 5-1g
Model hydraulic conductivity zones in ash layer 7
Figure 5-1h
Model hydraulic conductivity zones in ash layer 8
Figure 5-2
Cross-section through Active Ash Basin downstream dam
showing hydraulic conductivity (colors)
Figure 5-3a
Model horizontal hydraulic conductivity zones in saprolite layer 9
Figure 5-3b
Model horizontal hydraulic conductivity zones in saprolite layer
10
Page vi

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF FIGURES (CONTINUED)
Figure 5-3c
Model horizontal hydraulic conductivity zones in saprolite layers
11 and 12
Figure 5-3d
Model horizontal hydraulic conductivity zones in the saprolite
layer 13
Figure 5-4a
Model horizontal hydraulic conductivity zones in transition zone
layer 14
Figure 5-4b
Model horizontal hydraulic conductivity zones in transition zone
layer 15
Figure 5-4c
Model horizontal hydraulic conductivity zones in transition zone
layer 16
Figure 5-5a
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 17
Figure 5-5b
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 18
Figure 5-5c
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 19
Figure 5-5d
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 20
Figure 5-5e
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 21
Figure 5-5f
Model horizontal hydraulic conductivity zones in fractured
bedrock layer 22
Figure 5-6a
Model horizontal hydraulic conductivity zones in deep bedrock
layer 23
Figure 5-6b
Model horizontal hydraulic conductivity zones in deep bedrock
layer 24
Figure 5-6c
Model horizontal hydraulic conductivity zones in deep bedrock
layers 25 - 28
Figure 5-7 Comparison of observed and computed heads from the calibrated
steady state flow model
Figure 5-8 Simulated hydraulic heads in transition zone
Figure 5-9 Simulated heads in fractured bedrock prior to decanting
Figure 5-10 Simulated local ash basin groundwater flow system in transition
zone
Figure 5-11 Boron, sulfate, and TDS source zones for the historical transport
model calibration
Page vii

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF FIGURES (CONTINUED)
Figure 5-12
Simulated pre -decanting maximum boron calibrated
concentrations in all non -ash layers
Figure 5-13
Simulated pre -decanting maximum sulfate calibrated
concentrations in all non -ash layers
Figure 5-14
Simulated pre -decanting maximum TDS calibrated concentrations
in all non -ash layers
Figure 6-1
Simulated hydraulic heads in transition zone layer 15 post -
decanting
Figure 6-2
Simulated maximum boron concentrations in all non -ash layers
after 1 year of decanting
Figure 6-3a
Excavation closure design for ASA used in both closure -in -place
and closure -by -excavation simulations (from AECOM, 2019)
Figure 6-3b
Simulated groundwater flow system in transition zone after ASA
excavation
Figure 6-4a
Closure -in -place closure design for AAB used in simulations (from
AECOM, 2019)
Figure 6-4b
Closure -in -place closure design for U5 AB used in simulations
(from AECOM, 2019)
Figure 6-5
Drain system simulated after closure -in -place
Figure 6-6
Simulated hydraulic heads in transition zone layer 15 for closure -
in -place
Figure 6-7a
Simulated maximum boron concentrations in all non -ash layers at
the time of closure -in -place
Figure 6-7b
Simulated maximum boron concentrations in all non -ash layers 24
years after closure -in -place
Figure 6-7c
Simulated maximum boron concentrations in all non -ash layers 74
years after closure -in -place
Figure 6-7d
Simulated maximum boron concentrations in all non -ash layers
124 years after closure -in -place
Figure 6-7e
Simulated maximum boron concentrations in all non -ash layers
174 years after closure -in -place
Figure 6-8
Simulated hydraulic heads in transition zone layer 15 for closure -
in -place with active groundwater remediation
Figure 6-9a
Simulated maximum boron concentrations in all non -ash layers for
the closure -in -place scenario after 5 years of active groundwater
remediation
Page viii

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF FIGURES (CONTINUED)
Figure 6-9b
Simulated maximum boron concentrations in all non -ash layers for
the closure -in -place scenario after 29 years of active groundwater
remediation
Figure 6-9c
Simulated maximum boron concentrations in all non -ash layers for
the closure -in -place scenario after 79 years of active groundwater
remediation
Figure 6-9d
Simulated maximum boron concentrations in all non -ash layers for
the closure -in -place scenario after 129 years of active groundwater
remediation
Figure 6-9e
Simulated maximum boron concentrations in all non -ash layers for
the closure -in -place scenario after 179 years of active groundwater
remediation
Figure 6-10a
Simulated maximum sulfate concentrations in all non -ash layers
for the closure -in -place scenario after 5 years of active
groundwater remediation
Figure 6-10b
Simulated maximum TDS concentrations in all non -ash layers for
the closure -in -place scenario after 5 years of active groundwater
remediation
Figure 6-11a Excavation closure design for AAB used in simulations (from
Wood, 2019)
Figure 6-11b
Excavation closure design for U5 AB used in simulations (from
Wood, 2019)
Figure 6-12
Simulated drain network under closure -by -excavation
Figure 6-13
Simulated groundwater flow system in transition zone under
closure -by -excavation (model layer 15)
Figure 6-14a
Simulated maximum boron concentrations in all non -ash layers at
the time of closure -by -excavation
Figure 6-14b
Simulated maximum boron concentrations in all non -ash layers 21
years after closure -by -excavation
Figure 6-14c
Simulated maximum boron concentrations in all non -ash layers 71
years after closure -by -excavation
Figure 6-14d
Simulated maximum boron concentrations in all non -ash layers
121 years after closure -by -excavation
Figure 6-14e
Simulated maximum boron concentrations in all non -ash layers
171 years after closure -by -excavation
Figure 6-15
Simulated hydraulic heads in the transition zone (model layer 15)
for closure -with -excavation with active groundwater remediation
Page ix

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF FIGURES (CONTINUED)
Figure 6-16a Simulated maximum boron concentrations in all non -ash layers for
the closure -by -excavation scenario after 8 years of active
groundwater remediation
Figure 6-16b
Simulated maximum boron concentrations in all non -ash layers for
the closure -by -excavation scenario after 29 years of active
groundwater remediation
Figure 6-16c
Simulated maximum boron concentrations in all non -ash layers for
the closure -by -excavation scenario after 79 years of active
groundwater remediation
Figure 6-16d
Simulated maximum boron concentrations in all non -ash layers for
the closure -by -excavation scenario after 129 years of active
groundwater remediation
Figure 6-16e
Simulated maximum boron concentrations in all non -ash layers for
the closure -by -excavation scenario after 179 years of active
groundwater remediation
Figure 6-17a
Simulated maximum sulfate concentrations in all non -ash layers
for the closure -by -excavation scenario after 8 years of active
groundwater remediation
Figure 6-17b
Simulated maximum TDS concentrations in all non -ash layers for
the closure -by -excavation scenario after 8 years of active
groundwater remediation
Page x

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
LIST OF TABLES
Table 5-1
Observed, computed, and residual heads for the calibrated flow model
Table 5-2
Calibrated hydraulic conductivity parameters
Table 5-3
Water Balance on the groundwater flow system pre -decanted conditions
Table 5-4
Flow model sensitivity analysis
Table 5-5a
Ash basin boron source concentrations (µg/L) used in historical
transport model
Table 5-5b
Ash basin sulfate source concentrations (mg/L) used in historical
transport model
Table 5-5c
Ash basin TDS source concentrations (mg/L) used in historical transport
model
Table 5-6a
Observed and simulated boron concentrations (µg/L) in monitoring
wells
Table 5-6b
Observed and simulated sulfate concentrations (mg/L) in monitoring
wells
Table 5-6c
Observed and simulated TDS concentrations (mg/L) in monitoring wells
Table 5-7
Transport Model Sensitivity to the Boron Ka Values
Table 6-1
Active Groundwater Remediation Well Summary
Page xi

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
1.0 INTRODUCTION
This groundwater flow and transport model report provides basic model development
information and simulations of basin closure designs as well as results of corrective
action simulations for the Rogers Energy Complex — Cliffside Steam Station (Cliffside,
CSS, or Site). The Site is owned by and operated by Duke Energy Carolinas, LLC (Duke
Energy) and is located in Mooresboro, Rutherford and Cleveland counties, North
Carolina. The Station is situated on the southern bank of the Broad River, which
provides water for Site operations (Figure 1-1). Model simulations were developed
using flow and transport models MODFLOW and MT3DMS. Due to historical ash
management and wastewater discharge activities at the Site, a numerical model was
developed to evaluate transport of inorganic constituents of interest (COIs) in the
groundwater downgradient of the ash basins. Numerical simulations of groundwater
flow and transport have been calibrated to pre -decanting conditions and used to
evaluate different scenarios being considered as options for closure of the ash basins.
The simulations were also used to design a corrective action system that would achieve
compliance with North Carolina Administrative Code, Title 15A, Subchapter 02L,
Groundwater Classification and Standards (02L) within approximately six years of
operation. This model and report is an update of a previous model developed by
SynTerra in conjunction with Falta Environmental, LLC and Frx Partners (SynTerra,
2018b).
1.1 General Setting and Background
The Site encompasses 1,000 acres which includes the active ash basin (AAB), ash storage
area (ASA), former Units 1-4 ash basin (U1-4 AB), and the Unit 5 inactive ash basin (U5
AB). The Broad River is located north of the Site, and Suck Creek runs north to south
within the Site.
The CSS became operational in 1940. It began as a coal-fired, electricity -generating
station with a capacity of 198 megawatts (MW) from Units 1-4. Electricity -generating
capacity was expanded in 1972 to 754 MW when Unit 5 became operational. Unit 6
became operational in 2012. Units 1 through 4 were retired in October 2011. Natural gas
infrastructure was completed to co -fire as much as 40 percent natural gas on Unit 5 and
as much as 100 percent on Unit 6. The first fire for natural gas at Unit 5 occurred in
October 2018 and the first fire for natural gas at Unit 6 occurred in November 2018.
The coal ash residue and other liquid discharges from coal combustion processes at the
CSS have historically been managed in the CSS ash basins, which consist of the AAB,
the U14 AB, and the U5 AB. The AAB is approximately 86 acres, ASA is approximately
Page 1-1

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
seven acres, U14 AB was approximately 14 acres, and U5 AB is approximately 46 acres.
Discharge from the AAB is currently permitted by the North Carolina Department of
Environmental Quality (NCDEQ) Division of Water Resources (DWR) under National
Pollutant Discharge Elimination System (NPDES) Permit NC0005088. Duke also
operates a Coal Combustion Products (CCP) Industrial Landfill (CCP Landfill) in
accordance with the North Carolina Department of Environmental Quality (NCDEQ)
Solid Waste Sections (SWS) on the property.
The AAB was constructed in 1975 and, that year, began receiving variable inflows from
the Unit 5 fly ash handling system, Unit 5 bottom ash handling system, cooling tower
blowdown, stormwater runoff from yard drainage, coal pile runoff, gypsum pile runoff,
limestone pile runoff, landfill leachate, and wastewater streams generated from
emission monitoring equipment, precipitators, and the Selective Catalytic Reduction
Unit. The AAB also received treated sanitary wastewater, miscellaneous cleaning
wastes, domestic package plant wastewater (through the yard sumps) and water
treatment system wastes (filter backwash, demineralizer regeneration waste, reverse
osmosis rinse water, and clarifier solids). The discharge from the AAB is permitted by
the NCDEQ DWR under NPDES Permit NC0005088. The ash basin expanded in 1980 to
its current footprint.
Generating Unit 5 converted to dry fly ash and dry bottom ash handling systems. Unit
6 has been dry handling ash since it came online. On March 31, 2019, all Station
wastewater flows were routed to the new wastewater treatment system, which includes
a 14 acre lined retention basin (LRB) located in U1-4 AB footprint. The LRB was lined
with a dual -liner system comprised of a textured high -density polyethylene (HDPE)
geomembrane liner over a geosynthetic clay liner (GCL). The wastewater from the
wastewater treatment system is discharged to the Broad River in accordance with
NPDES Permit NC0005088. Decanting from the AAB commenced on March 31, 2019
with discharge monitoring at Outfall 002 in accordance with NPDES Permit NC0005088.
The unlined ASA is located north of the AAB. A spoil area that was previously referred
to as an ash storage area, is located to the east of the ASA. The heavily vegetated ASA is
located between the AAB and the Broad River. The ash in the ASA was removed from
the U14 AB, and was placed in the ASA in the 1970s. The ASA footprint, approximately
7 acres, contains approximately 204,000 tons of ash material. The ash storage area will
be excavated as part of the AAB closure activities.
The U1-4 AB was constructed in 1957 and began operating the same year. The U14 AB
was retired in 1977 once it reached capacity. The western portion of this ash basin was
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formerly converted into holding cells for storm and plant process water. Water from
those holding cells was pumped to the AAB to the east. The impounded ash material
within the U1-4 AB was previously capped with a soil cover approximately 2-feet-thick.
Excavation of the CCR historically deposited in the basin began in October 2015 and
concluded in February 2018, with the exception of minor ash removal that occurred
after the basin closure at the interior slopes of the dam. Approximately 450,000 tons of
ash were excavated from the U14 AB and placed in the lined CSS CCP Landfill. A LRB
and wastewater treatment plant were constructed within the U1-4 AB footprint and
began operating on April 1, 2019.
The U5 AB was constructed in 1970 (in advance of Unit 5 operations) and began
receiving sluiced ash from Unit 5 in 1972. The U5 AB was retired in 1980 when it
reached full capacity. The U5 AB is currently covered with a layer of topsoil with stable
vegetation and is used as a laydown yard for the Site. The U5 AB currently receives
stormwater from a localized drainage area. The stormwater is discharged from the
NPDES stormwater outfall SW009.
The Coal Combustion Products (CCP) Landfill, located south of the U5 AB, began
operating in late 2010. The CCP landfill is constructed with an engineered liner and
leachate collection system. The CCP Landfill is not located within the ash basin
groundwater drainage systems, and is not addressed in this flow and transport
modeling report update.
The CSS is located in the Piedmont region of NC. The topography in the area is hilly
with approximate elevations as high as 856 feet southwest of the U5 AB, to as low as 656
feet at the Broad River northeast of the Site. The AAB ponded water had a pool
elevation of approximately 764 feet prior to recent decanting efforts. Suck Creek runs
south to north within the Site and flows into the Broad River. In the groundwater
model, Suck Creek ranges from an elevation of 767 feet in the upstream part of Suck
Creek to an elevation of 658 feet at its confluence with the Broad River. The unconfined
groundwater system at the CSS is dominated by flow toward the Broad River north of
the ash basins, and generally toward Suck Creek, which flows in a north easterly
direction between the U5 AB and the AAB. A groundwater ridge exists south of Suck
Creek, and approximately follows the topography along Prospect Church Road and Fox
Place Road.
The subsurface at the Site is composed of saprolite, a transition zone, and bedrock. The
upper part of the bedrock is generally fractured and the majority of water bearing
fractures are encountered in the upper 50 feet of the bedrock. The groundwater flow is
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unconfined and the water table surface may occur in the saprolite, the transition zone,
or in the fractured bedrock.
1.2 Objectives
The 2018 groundwater flow and transport model has been further refined to gain a
better understanding of Site conditions. Since that time, stratigraphic layers have been
refined with additional boring log data. Additional assessment activities, such as the
installation of additional groundwater monitoring wells and multiple groundwater
sampling events, have resulted in an increase of data describing hydraulic head and
constituent of interest (COI) distribution, and are also included in the model. This
report describes the current understanding of the groundwater flow and transport
processes of mobile constituents at the Site.
The following data sources were used during calibration of the revised groundwater
flow and fate and transport model:
• Average Site -wide water levels measured in CAMA/CCR/Compliance
groundwater monitoring wells through April 2019.
• Groundwater quality data obtained from CAMA/CCR/Compliance sampling
events conducted through April 2019.
• Surface water elevations, as described in the Comprehensive Site Assessment
(CSA) Update (SynTerra, 2018), and from surface water surveys conducted in
2019.
• AAB pond water elevation during June 2019, provided by Duke Energy.
• Estimated recharge, as described in HDR Engineering, Inc (HDR) modeling
report (HDR, 2017).
• Information on private supply wells within a 0.5-mile radius of the ash basins
(HDR, 2014a and 2014b)
The model revision consists of three main activities:
• re -calibration of the steady-state groundwater flow model to hydraulic heads
averaged through April 2019;
• calibration of a transient model of boron, sulfate, and total dissolved solids (TDS)
using the revised flow model and COI concentrations measured through April
2019; and
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• development of predictive simulations of the possible closure scenarios and
corrective action at the Site.
The predictive simulations include consideration of complete excavation (closure -by -
excavation) (Wood 2019) of the coal ash basin at the Site and a closure -in -place
(AECOM 2019) design that involves placing an engineered cover system in the AAB
and U5 AB. Additional corrective action measures to accomplish accelerate
groundwater remediation are also considered.
Further, this flow and transport modeling report has been revised to include the results
of groundwater pumping tests performed in the ash basin, and results of a deep drilling
investigation near the ash basin dams.
The predictive simulations described above are not intended to represent a final
detailed closure design. These simulations use designs that are subject to change as the
closure plans are finalized. Corrective action designs might vary from those presented
as pilot testing progresses and additional field data is collected. The simulations are
intended to show the key characteristics of groundwater flow and mobile constituent
transport that are expected to result from the closure designs and groundwater
corrective action.
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2.0 CONCEPTUAL MODEL
The conceptual site model (CSM) for CSS is based primarily on the Comprehensive Site
Assessment Report (HDR, 2015a), the Comprehensive Site Assessment Update for the CSS
(SynTerra, 2018), the Corrective Action Plan Reports (HDR, 2015b, 2016; SynTerra 2019c).
The reports contain extensive detail and data related to most aspects of the CSM.
2.1 Aquifer System Framework
The aquifer system at the Site is unconfined. Depending on local topography and
hydrogeology, the water table surface might exist in the saprolite, the transition zone, or
in the fractured bedrock. At some isolated locations along streambeds, the upper units
(saprolite and transition zone) are absent. At other locations, the upper units might be
unsaturated, with the water table located in deeper units.
The hydraulic conductivity at the CSS site has been measured in a series of slug tests in
the different units. Eighteen slug tests were performed in the coal ash, with
conductivities ranging from 0.14 to 108 feet per day (ft/d).
Fifty-one (51) slug tests performed in wells screened in the saprolite layer yielded
hydraulic conductivities ranging from 0.28 to 42.5 ft/d. Ninety-nine (99) slug tests
performed in transition zone layer had results ranging from 0.0007 to 45.4 ft/d. Thirty-
eight (38) slug tests conducted in bedrock had hydraulic conductivity values ranging
from 0.001 to 126 ft/d. It should be noted that most of the bedrock wells are screened
near the top of the bedrock surface, and the conductivity of the deeper bedrock would
be expected to be lower.
The range of observed conductivity in the transition zone and bedrock wells (from
nearly 0 ft/d to 45.4 ft/d) highlights the significant degree of heterogeneity in the system.
2.2 Groundwater Flow System
The unconfined groundwater system at the CSS is dominated by flow toward the Broad
River north of the ash basins and toward Suck Creek in the shallow flow layer in the
central portion of the Site. Suck Creek flows northeasterly between the U5 AB and the
AAB.
The AAB was formed by rerouting Suck Creek and damming the original channel.
Ponded water at the AAB is being decanted. Decanting is expected to be complete in
March 2020. The U5 AB was constructed by damming a former perennial stream valley.
The U1-4 AB was constructed in a low-lying area along the Broad River.
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The former stream valleys are bound by natural ridges. One ridge east of the AAB runs
south, parallel to Suck Creek. The second ridge runs west of the U5 AB and the CCP
Landfill. The stream valley system generally slopes to the north toward the Broad River.
Inside the groundwater divides, some of the groundwater flows toward the adjacent
ash basins. The groundwater flow direction provides natural control of potential COI
migration within the former stream valley system.
The groundwater system at the Site is recharged from infiltrating rainwater and water
that infiltrates from the ash basins. The average value of recharge in the vicinity of CSS
was estimated at 7.5 inches per year. The Haven (2003) NC recharge map does not
show values for Cleveland County. The average value in adjacent counties, however, is
consistent with the average value estimated here. A reduced rate of recharge (0.004
inches per year) was assumed for the power plant and large buildings. Based on the
results from lined landfill simulations, the lined areas of the CCP Landfill was assigned
a low infiltration rate of 0.00054 inches per year (in/yr) based on results from landfill
cover simulations.
There are 71 private water wells that have been identified within 0.5 miles of the three
ash basin compliance boundaries (SynTerra, 2018). Most of these wells are located east
and south of the AAB, and west of the CCP landfill. Pumping rates for the private wells
were not available, and completion depths were only available for a few wells. The 16
private water wells not included in the model boundary are located north of the Broad
River, which is a hydrological boundary.
2.3 Hydrologic Boundaries
Broad River, Suck Creek, and smaller drainages in the region of the CSS serve as the
major hydrologic boundaries in the area.
2.4 Hydraulic Boundaries
It was assumed that the bedrock below the depth of the bottom -modeled layer is
impermeable, and that a no -flow boundary was used to represent this condition.
2.5 Sources and Sinks
Groundwater flow out of the ponded water in the ash basin and areal recharge are
sources of water to the groundwater system. Groundwater discharges to the Broad
River, Suck Creek, and to numerous small streams. The private water wells within the
model area remove only a small amount of water from the overall hydrologic system.
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2.6 Water Budget
Over the long term, the rate of water inflow to the study area is equal to the rate of
water outflow from the study area. Water enters the groundwater system from the
ponded water in the basin and recharge. Water leaves the system through discharge to
the Broad River, Suck Creek, and other small drainages and through private wells.
2.7 Modeled Constituents of Interest
Arsenic, boron, chromium, hexavalent chromium, cobalt, iron, manganese, pH,
strontium, sulfate, thallium, TDS, vanadium, total uranium, and radium have been
identified as constituents of interest (COIs) for groundwater at the CSS (SynTerra, 2018).
Three conservative COIs that are present beyond the compliance boundary were
selected for modeling at the CSS. The COIs selected consist of boron, sulfate, and TDS.
Of these three constituents, boron is the most prevalent in groundwater in the AAB.
Sulfate, however, is the most prevalent in groundwater in U1-4 AB and U5 AB
compared to boron and TDS. Boron is present in groundwater at concentrations greater
than the 02L standard below the AAB, ASA, and within the northern U5 AB. A boron
plume extends to wells north of the AAB within the ASA, west of the AAB upstream
dam, northeast of the AAB downstream, and southwest of the AAB. Boron is found in
wells screened in the saprolite, the transition zone, and the bedrock. Boron
concentrations in background wells were detected concentrations less than the 02L
standard, and are generally less than the laboratory reporting limit. Because boron is
the dominant mobile constituent in the AAB and sulfate is the most dominant
constituent in U1-4 AB and U5 AB, this report primarily focuses on boron within the
AAB, and sulfate within U1-4 and U5 AB. TDS is not as prevalent as boron and sulfate
but is reported greater than the 02L standards in and downgradient of the ash basins.
2.8 Constituent Transport
The COIs present in coal ash dissolve in ash pore water. As water infiltrates through
the ash, water containing COIs can enter the groundwater system. Once in the
groundwater system, the COIs are transported by advection and dispersion and subject
to retardation due to adsorption to solids. If the COIs reach a hydrologic boundary or
water sink, they are removed from the groundwater system, and they enter the surface
water system, where in general, they are greatly diluted. At CSS, boron, sulfate, and
TDS are the primary conservative constituents that are migrating from the ash basins in
groundwater. The less mobile, more geochemically controlled constituents (i.e., arsenic,
selenium, chromium) will follow the same flow path as boron, but to a lesser extent. The
less mobile, geochemically controlled constituents are modeled separately using a
geochemical model.
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3.0 COMPUTER MODEL
3.1 Model Selection
The numerical groundwater flow model was developed using MODFLOW (McDonald
& Harbaugh, 1988), a three-dimensional (31)) finite difference groundwater model
created by the United States Geological Survey (USGS). The chemical transport model
is the Modular 3-D Transport Multi -Species (MT3DMS) model (Zheng & Wang, 1999).
MODFLOW and MT3DMS, widely used in industry and government, and are
considered to be industry standards. The models were assembled using the Aquaveo
Groundwater Modeling Systems (GMS) 10.3 graphical user interface
(http://www.aquaveo.com).
3.2 Model Description
MODFLOW uses Darcy's law and the conservation of mass to derive water balance
equations for each finite difference cell. MODFLOW considers 3D transient
groundwater flow in confined and unconfined heterogeneous systems, and it can
include dynamic interaction with pumping wells, infiltration wells, recharge,
evapotranspiration, rivers, streams, springs, lakes, and swamps.
This study uses the MODFLOW-NWT version (Niswonger, et al., 2011). The NWT
version of MODFLOW provides improved numerical stability and accuracy for
modeling problems with variable water tables. That improved capability is helpful in
the present work where the position of the water table in the ash basins can fluctuate
depending on the conditions under which the basin is operated and on the closure
action activities.
Some of the CSS flow models were challenging to run due to the topography and layers
that become unsaturated in the model. It was found that using the NWT solver options
"MODERATE" with the xMD matrix solver could overcome these difficulties.
MT3DMS uses the groundwater flow field from MODFLOW to simulate 3D advection
and dispersion of the dissolved COIs, including the effects of retardation due to COI
adsorption to the soil matrix.
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4.0 GROUNDWATER FLOW AND TRANSPORT MODEL
CONSTRUCTION
The flow and transport model of the site was created through a series of steps
• Step 1: Build a 3D model of the Site hydrostratigraphy based on field data.
• Step 2: Determine the model domain and construct of the numerical grid.
• Step 3: Populate the numerical grid with flow parameters, which were adjusted
during the steady-state flow model calibration process.
• Step 4: Once the flow model is calibrated, flow parameters are used to develop a
transient model of the historical flow patterns.
• Step 5: Develop historical constituent transport simulations using the historical
flow model.
4.1 Model Domain and Grid
The initial steps in the model grid generation process were the determination of the
model domain and the construction of a 3D hydrostratigraphic model. The model has
dimensions of approximately 13,900 feet by 9,400 feet, and it is oriented in a north -south
orientation. (Figure 4-1). The model is bounded generally to the north by the Broad
River, and to the east by Ashworth Creek. The distance to the boundary from the ash
basins is large enough to prevent boundary conditions from artificially affecting the
results near the basin.
The ground surface of the model was developed by HDR and was interpolated from the
North Carolina Floodplain Mapping Program's 2010 LiDAR elevation data. These data
were supplemented by on -Site surveys conducted by Duke Energy in 2014. The
elevations used for the top of the ash surface in the AAB ponded waters were modified
from the bathymetric data to provide a model surface that can accommodate closure
designs regrading ash under different closure options. For simulations of pre -
decanting, the AAB ponded waters in the model are given a large hydraulic
conductivity to represent the open water conditions in the AAB ponded waters.
The hydrostratigraphic model (called a solids model in GMS) consists of five units: ash
basin, saprolite, transition zone, upper fractured bedrock, and deeper bedrock. The
elevation of contacts between these units (ash, saprolite, transition zone, and bedrock)
were determined from boring logs from previous studies by HDR (2015a; 2016). The
contact elevations were estimated by HDR for locations where well logs were not
available by extrapolation of the borehole data using the Leapfrog Hydro geologic
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modeling tool. This program was used by HDR to develop surfaces defining the top of
the saprolite, transition zone, and bedrock. While the contact between the upper units
(ash, saprolite, transition zone, bedrock) are well defined, the division of the bedrock
into an upper fractured zone and deeper bedrock was subjective. For the purposes of
model construction, the upper fractured zone is assumed to be 120 feet thick. The
deeper bedrock extends another 430 feet below the upper zone for a total bedrock
thickness of about 550 feet in the model. The upper bedrock zone in the model was
given a heterogeneous hydraulic conductivity distribution to represent more and less
fractured zones.
Figure 4-2 shows a fence diagram of the 3D hydrostratigraphic unit viewed from the
northwest, with a vertical exaggeration of 5x. The light grey material corresponds to
the ash basin, the light tan material is the saprolite, the red material is the transition
zone, the purple material is the upper fractured part of the bedrock, and the black
material is the deep bedrock.
The numerical model grid is shown in Figure 4-3. The grid is discretized in the vertical
direction using the solids model (Figure 4-2) to define the numerical model layers. The
top eight model layers represent the ash basins, including the dams that form the
basins. Model layers 9 to 13 represent the saprolite. Model layers 14, 15 and 16
represent the transition zone. Layers 17 to 22 represent the upper fractured part of the
bedrock, while layers 23 to 28 represent deeper parts of the bedrock (which also may be
fractured). The model varies in thickness from approximately 600 feet to 650 feet.
The discretization in the horizontal direction is variable with smaller grid cells in and
around the ash basin area. The minimum horizontal grid spacing in the finely divided
areas is approximately 30 feet, while the maximum grid spacing near the outer edges of
the model is approximately 160 feet. The grid contains a total of 731,868 active cells in
28 layers.
4.2 Hydraulic Parameters
The horizontal hydraulic conductivity and the horizontal to vertical hydraulic
conductivity anisotropy ratio are the main hydraulic parameters in the model. The
distribution of these parameters is based primarily on the model hydrostratigraphy,
with additional horizontal and vertical variation. Most of the hydraulic parameter
distributions in the model were heterogeneous across a model layer. The geometries
and parameter values of the heterogeneous distributions were determined largely
during the flow model calibration process. Initial estimates of parameters were based
on literature values; results of slug test, pumping test, and core tests, and simulations
performed using a preliminary flow model. The hydraulic parameter values were
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adjusted during the flow model calibration process described in Section 5.0 to provide a
best fit to observed water levels in observation wells. Slug test data from hundreds of
wells at the Duke Energy coal ash basin sites in North Carolina and pumping tests from
six Duke Energy coal ash basin sites, are shown in Figure 4-4 through Figure 4-7.
The hydraulic conductivity of coal ash measured at 14 sites in North Carolina ranges
over 4 orders of magnitude, with a geometric mean value of approximately 1.8 ft/d.
Ash hydraulic conductivity values estimated by interpreting slug test data at CSS
ranged from 0.14 ft/d to 108 ft/d. Two pumping tests were performed in the ash within
the AAB at CSS to help refine the value of this parameter. One test was performed by
pumping a well screened at the bottom of the ash, and another with the pumping well
screened in the middle of the ash. Hydraulic conductivity, based on analytical and
numerical solutions, ranged from 8 ft/d to 70 ft/d. These values are larger than have
been measured in ash pump tests at other sites, and likely reflect a localized zone of
high permeability bottom ash.
Pumping tests were also conducted in the ash basins at five other Duke Energy sites.
Those pumping tests were analyzed using parameter estimation methods with
analytical solutions and with site -specific numerical models. The results are included in
Figure 4-4 graph (SynTerra, 2019a; SynTerra, 2019b).
The hydraulic conductivities from hundreds of slug tests performed in saprolite wells at
10 Duke Energy sites within the Piedmont are shown in Figure 4-5. These range over 4
orders of magnitude, with a geometric mean value of 0.9 ft/d. Slug tests performed at
wells completed in saprolite at CSS indicate that hydraulic conductivity ranges from
0.28 to 42.5 ft/d.
Transition zone hydraulic conductivities from hundreds of slug tests at 10 Duke Energy
sites in the Piedmont range over 5 orders of magnitude, with a geometric mean value of
0.9 ft/d (Figure 4-6). The measured values at the Site range from 0.0007 to 45.4 ft/d.
Fractured bedrock hydraulic conductivities from hundreds of slug tests at 10 Duke
Energy sites in the Piedmont of North Carolina (Figure 4-7) range more than 6 orders of
magnitude, with a geometric mean value of 0.3 ft/d. The measured values at CSS range
from 0.0005 ft/d to 126 ft/d.
Hydraulic conductivity data obtained from slug tests and pumping tests conducted on
wells at the CSS site span smaller ranges than the overall dataset, and in some cases the
geometric mean values are quite different (Figure 4-4 to Figure 4-7). For example, the
geometric mean hydraulic conductivity for coal ash from the slug tests at CSS site is
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approximately 5.6 ft/d, whereas it is approximately 1.8 ft/d over the entire dataset.
However, the datasets from CSS, and from all the sites, indicate that hydraulic
conductivity varies spatially by several orders of magnitude due to heterogeneities.
4.3 Flow Model Boundary Conditions
The Broad River forms a hydraulic boundary north of the ash basins. The river is
treated as a general head boundary in the uppermost active model layer with an
elevation ranging from approximately 665 feet to 655 feet.
The eastern part of the model is bound by Ashworth Creek, which is simulated as a
drain. Ashworth Creek flows from the south and discharges into the Broad River.
The southern model boundary does not align with defined hydraulic features. This
boundary is located approximately one mile from the ash basin, and there is a major
groundwater divide between the model boundary and the AAB. Part of the southern
model boundary is treated as a general head boundary with the head set to an elevation
of 30 feet below the ground surface, except in stream valleys, where a no flow boundary
is used perpendicular to the streams. The flow in these valleys is dominated by flow
toward the streams, which are modeled as drains. The western boundary is treated as a
general head boundary with the head set 30 feet below the ground surface, and as a no -
flow boundary as it crosses several creeks approximately perpendicular to the streams,
which are treated as drains in the model. This boundary is approximately a 0.5 miles
away from the U5 AB.
4.4 Flow Model Sources and Sinks
The sources and sinks of groundwater within the model domain consist of recharge,
ponds, streams, groundwater pumping, and infiltration wells.
The flow model sources and sinks consist of the Broad River and Suck Creek, the AAB
ponded water, Ashworth Creek, recharge, streams, water supply wells, and wet areas
that are assumed to directly drain into the AAB.
Recharge is a significant hydrologic parameter in the model, and the distribution of
recharge zones in the model is shown in Figure 4-8. As described in Section 2.2, the
recharge rate for the CSS site was estimated to be 7.5 in/yr. Due to the large areas of
roof and pavement, the recharge rate for the Station was set to 0.004 in/yr. The AAB
ponded water and sluicing channel are treated as general head boundaries and have
zero rainfall recharge, but part of the southern AAB has an increased rate of 14 inches
per year to simulate sluicing, which was terminated in April 2018. The recharge rate in
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the dams was set to 2 in/yr. The recharge rate through the CCP Landfill was set to
0.00054 inches per year based on landfill simulations.
The Broad River and the AAB ponded water were treated as general head zones, and
Suck Creek was treated using the MODFLOW RIVER package in the model (Figure 4-9
and Figure 4-10). The northern AAB ponded water is maintained at an elevation of
759.4 feet, and the southern AAB ponded water has a head elevation of 765 feet. Suck
Creek ranges from an elevation of 762 feet in the upstream part of Suck Creek to an
elevation of 658 feet at the confluence of Suck Creek and the Broad River. The Broad
River ranges from an elevation of 664.8 feet at the western border of the model to 653.7
feet at the eastern border of the model.
The many creeks exert significant local control on the hydrology in the model. These
features are shown as green lines in Figure 4-9. The position of these creeks was
determined mainly from the topographic map (Figure 1-1), supplemented by three site
visits where each drainage near the ash basins and Suck Creek were inspected. The
elevation of locations along the creeks that were not surveyed, was determined from the
surface LIDAR elevations, and was assumed to be three feet below the ground surface.
The creeks were simulated using the DRAIN feature in MODFLOW with a high
conductance value (10 ftz/d/ft to 100 W/d/ft).
The southern part of the AAB contained several areas of standing water and was
modeled as a wetland area using the DRAIN feature. (Figure 4-10). The AAB contains
one main wastewater channel (former sluicing channel) at an approximate elevation of
766 feet and also includes a northern ponded water area and southern ponded water
area. The AAB ponded water is included in the model as a general head condition
(Figure 4-10).
Figure 4-11 shows the location of private water supply wells in the model area. There
are no public supply wells that were identified within a 0.5-mile radius of the ash basin
compliance boundaries (SynTerra, 2018).
There are 77 private wells inside the model boundary. This number is larger than the 71
wells that were identified within a 0.5-mile radius of the ash basin compliance
boundary (SynTerra, 2018) due to the fact that the model extends approximately one
mile beyond the ash basin waste boundary. Where depth data were available, the
private wells were represented as screened over the known depth. In most cases, the
well depths were unknown, and the wells were assumed to be screened in the upper
part of the transition zone and/or fractured bedrock in model layers 14 to 16. The
pumping rates were also not known, but the model simulated a pumping rate of 280
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gallons per day, which is an average water use for a family of four (Treece et al., 1990;
USGS, 1987, 1995). Septic return was assumed to be 94 percent of the pumping rate
(Treece et al., 1990; Daniels et al., 1997; Radcliffe et al., 2006). The septic return was
injected into layer 14 in the model.
4.5 Flow Model Calibration Targets
The steady-state flow model calibration targets were historically averaged water level
measurements from 312 observation wells through the second quarter of 2019. These
wells include wells screened in each of the hydrostratigraphic units, including many
sets of nested wells. Wells not included in the calibration were classified as "dry" or
"non -water producing" wells during site investigations.
4.6 Transport Model Parameters
The transport model uses a sequence of steady-state MODFLOW simulations to provide
the time -dependent groundwater velocity field. The MODFLOW simulation started in
January 1957, and it continued through the second quarter of 2019. The MODFLOW
simulation reflects post-1975 flow conditions at the AAB, where Suck Creek has been
rerouted, and the original channel has been dammed to form the ash basin. The flow
model has transient changes that reflect the start and end of operations at the U5 AB
and capping of the CCP Landfill. The transport model begins in 1957 with the U14 AB
serving as the only source of boron in the model. The U5 AB becomes active in 1972
and the AAB and ASA become active in 1975 in the model. Once they are activated, the
COI sources in the ash layers are held at a specified concentration until the end of the
simulation in 2019. The COI concentrations in the ash are allowed to vary in the
predictive simulations, using an equilibrium Ka adsorption model to describe the
partitioning of COIs between the ash pore water and the solid ash.
The key transport model parameters (besides the flow field) are the boron, sulfate, and
TDS source concentrations in the ash, and the boron, sulfate, and TDS soil -water
distribution coefficients (Ka). Other parameters are the longitudinal, transverse, and
vertical dispersivities, and the effective porosity. The source concentrations in the AAB,
ASA, U1-4 AB, and U5 AB, were initially estimated from the ash pore water
concentrations and from concentrations in nearby wells. During the transport model
calibration process, the basin and other areas were subdivided, and different
concentrations were assigned to different zones at different times. The timing of the
COI in sources appearing at AAB, U1-4 AB, U5 AB, and the ASA locations corresponds
to the time when they became active (1957, 1972, and 1975, respectively).
The numerical treatment of adsorption in the model requires special consideration
because part of the system is a porous media (the ash, saprolite, and transition zone)
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with a relatively high porosity, while the bedrock is a fractured media with very low
matrix porosity and permeability. As a result, transport in the fractured bedrock occurs
almost entirely through the fractures. The MODFLOW and MT3DMS flow and
transport models used here simulate fractured bedrock as an equivalent porous media.
With this approach, an effective hydraulic conductivity is assigned to the fractured rock
zones so that it produces the correct Darcy flux (volume of water flowing per area of
rock per time) for a given hydraulic gradient. However, because the water flows almost
entirely through the fractures, this approach requires that a small effective porosity
value (0.05 or less) be used for the transport calculations to compute a realistic pore
velocity.
The velocity of a COI, Vc, is affected by both the porosity, 0, and the retardation factor,
R, as:
V, — V
OR (la)
Where the retardation factor is computed internally in the MT3DMS code using a
conventional approach:
R=1+pbK a
0 (lb)
V is the volumetric flux (Darcy velocity), pb is the bulk density and Ka is the distribution
coefficient assuming linear equilibrium sorption. The retardation factor for boron in
fractured rock is expected to be in the same range as R for porous media. However, it is
apparent from (1b) that R can become large if 0 is reduced, and Ka is held constant. This
is unrealistic, and the reason a small Ka value is assigned to the bedrock, where the
effective porosity is due to the fractures and is low. This reduction of Ka is justified on
physical grounds because COIs in fractured rock interact with only a small fraction of
the total volume in a grid block, whereas COIs in porous media are assumed to interact
with the entire volume. The Ka for boron in the bedrock layers of the model was
reduced by scaling it to the bedrock porosity. This causes the retardation factor in the
fractured rock to be similar to R in the saprolite and transition zone.
Ash leaching tests were performed on four (4) samples from CSS using the USEPA
Method 1316 (LEAF). Two (2) were performed at the AAB; one (1) was performed at the
U5 AB; and one (1) was performed at the ASA. The leaching data were analyzed to
develop a Ka value for boron in the coal ash. The average of those test values were 0.53
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milliliters per gram (mL/g). The modeling approach for the predictive simulations of
future boron transport allow the boron concentration in the ash to vary with time in
response to flushing by groundwater. Using the Ka value derived from the ash leaching
tests ensures that the model response of the boron in the ash to groundwater flushing is
realistic.
The Ka values for the boron outside of the ash basin was treated as a calibration
parameter. Boron is expected to be mobile, and to have a low Ka value. The calibrated
Ka values for the saprolite and transition zone layers were 0.53 mL/g. In the fractured
bedrock, a significantly lower value was used as described above of 0.02 mL/g.
The Ka values used for sulfate in the model were 0.3 mL/g in the ash, 0.2 mL/g in the
saprolite and transition zone, and 0.01 mL/g in the bedrock. The Ka values used for TDS
in the model were also 0.15 mL/g in the ash, 0.1 mL/g in the saprolite and transition
zone, and 0.01 mL/g in the bedrock.
The longitudinal dispersivity was assigned a value of 20 feet, the transverse dispersivity
was set to 2 feet, and the vertical dispersivity was set to 0.02 feet. The effective porosity
was set to a value of 0.3 in the unconsolidated layers, and to 0.01 in all of the bedrock
layers. The soil dry bulk density was set to 1.6 g/mL.
4.7 Transport Model Boundary Conditions
The transport model boundary conditions are specified as no -flow on the exterior edges
of the model except where general head boundaries exist. With a general head
condition, water can flow into or out of the model, depending on the head in each
gridblock relative to the specified head. If water flows into the model, the concentration
of COIs in the incoming water are set to zero. Water that flows out of the model
removes associated COIs based on their concentration. All of the general head water
bodies (lakes, river, and ponds) are treated in this manner. The infiltrating rainwater is
assumed to be clean, and enters from the top of the model. The AAB ponded water
receive special treatment, where the water level is maintained using a general head
hydraulic boundary, but the COI concentrations are specified in model cells below the
water surface.
The initial condition for the historical conditions transport model assumes a boron
concentration of 0 µg/L throughout the Site in 1957. No background concentrations are
considered.
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4.8 Transport Model Sources and Sinks
The AAB, ASA, U1-4 AB, and U5 AB are the source of boron and other COIs in the
model. During the historical transport simulation, these sources are simulated by
holding the COI concentrations constant in cells located inside the ash in these zones.
The COI concentrations from the historical transport simulation form the initial
condition for the predictive simulations of future transport at the Site. The predictive
simulations do not hold the COI concentrations constant in the ash source zones, and
these mobile constituents can wash out of the ash over time. The boron Ka value used
for the ash was measured in ash leaching tests using ash from the Site to ensure that the
simulated boron leaching rate is realistic.
Affected soil and rock at the Site can serve as a secondary source of groundwater COIs
like boron, sulfate, and TDS. This is accounted for in the model by continuously
tracking the COI concentrations over time in the saprolite, transition zone, and rock
materials throughout the model. The historical transport model simulates the migration
of COIs through the soil and rock from the ash basin, and these results are used as the
starting concentrations for the predictive simulations. Therefore, even if all of the coal
ash is excavated, the transport model predicts lingering concentrations in groundwater
from the residuals remaining in the soil beneath the ash.
The transport model sinks are the constant head lakes, river, ponds, creeks, and drains.
As groundwater enters these features, it is removed along with any dissolved
constituent mass. Similarly, if water containing a constituent were to encounter a
pumping well, the constituent is removed with the water.
4.9 Transport Model Calibration Targets
The transport model calibration targets are boron concentrations measured in 293
monitoring wells in the first and second quarter of 2019. All sampled wells are
included in the calibration.
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5.0 MODEL CALIBRATION TO PRE -DECANTING CONDITIONS
5.1 Flow Model Calibration
The flow model was calibrated in stages starting with a relatively simple layered model.
All calibration was done by manual adjustments of parameters, simultaneously
matching the recent water levels measured in observation wells (Table 5-1). Additional
flow model calibration was required to also match the pre -decanting COI distributions.
The primary calibration parameters are the 31) distributions of hydraulic conductivity.
Each model layer has been subdivided into hydraulic conductivity zones. These model
conductivity zones (Figure 5-la-h, Figure 5-3a-d, Figure 5-4a-c, Figure 5-5a-g, and
Figure5-6a-c) and the calibrated hydraulic conductivity values assigned to each zone in
each layer are listed in Table 5-2.
Starting at the top of the model, in layers 1 through 8, the layers represent both the coal
ash and the ash basin dams. It was important to calibrate the conductivity of the dam
fill material in these layers (Figure 5-1a through Figure 5-1h; Figure 5-2) to match the
high head values in wells located in and near the dam. The dam fill material is thicker
in deeper layers to approximate a 3:1 dam slope (Figure 5-2), and it has a calibrated
conductivity of 0.07 to 0.5 ft/d. This relatively variable conductivity of the dam fill was
required to simultaneously match the hydraulic heads of wells in and below the dam.
In the current steady-state flow model, the grid cells in the U5 AB and AAB were set at
a higher elevation than the current ash elevations to allow simulation of future closure
scenarios where ash would be stacked. A high hydraulic conductivity (200 ft/d) was
applied to stacked areas above the current ash basin elevations. The hydraulic
conductivity of the ash was assumed to be 2.0 ft/d from analytical and numerical
pumping test analyses (SynTerra 2019a; SynTerra 2019b). The results are included in
Figure 4-4. The pre -decanting conditions flow model is insensitive to the ash
conductivity because the water levels around the AAB are controlled by the AAB
ponded water elevation. The value of 2 ft/d used was close to the mean value of more
than 200 slug tests performed at 14 coal ash basin sites in North Carolina (Figure 4-4);
that falls within the range of values measured at CSS, although it is lower than the
values that were measured in the ash pumping tests at the Site.
The conductivity of the saprolite calibrated slightly higher to the west of Suck Creek to
approximate the conductivity observed at the monitoring wells. A high hydraulic
conductivity of 5 ft/d represents the alluvial channel along the Broad River. These units
are thin below the center of the Broad River dam. To the east of the dam, a zone of high
permeability was required to match the boron concentrations in wells in this area. A
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zone of lower conductivity was used to reproduce hydraulic heads in the model for
some sections under the AAB.
The calibrated background conductivity for the transition zone (layers 14 to 15) was 3.0
ft/d. This value falls near the average value for slug tests performed in the transition
zone at 10 Piedmont Sites in North Carolina (Figure 4-6). The transition zone is
heterogeneous, with values ranging from 0.08 ft/d to 5.0 ft/d (Figure 5-4a through
Figure 5-4c and Table 5-2).
The upper bedrock zone in the model includes layers 17 to 20, and is approximately 70
feet thick. The background conductivity value used in the model of 0.04 ft/d falls
within the range of values measured from slug tests at 10 Piedmont sites in North
Carolina, and in slug tests performed at the CSS (Figure 4-7). The background
conductivity value used in the model is somewhat lower than the geometric mean value
measured in slug tests, to better match observed heads.
Model layer 16 represents some areas of transition zone and fractured bedrock, but it
has a lower background conductivity than the shallower layers (Figure 5-4c). Just west
of the AAB, a zone of "high" conductivity (1 ft/day) was required to recreate the
observed boron transport in this area. Higher hydraulic conductivities were used
around U5-2BR; U5-5BR; GWA-31BRA (Figure 5-5a through Figure 5-5g) to better
calibrate the hydraulic heads within these areas. The slug test analysis for U5-2BR was
approximately 3 ft/d, which is close to the hydraulic conductivity used in the model
calibration in this area.
The upper bedrock conductivity in layers 17 to 22 ranges from 0.006 ft/d to 2 ft/d in the
model (Figure 5-5a through Figure 5-5g and Table 5-2). The very low value was used
to approximate the hydraulic head elevations observed in two wells (GWA-12BRU and
GWA-54BRO) west of the Suck Creek dam. West of the southern AAB ponded water, a
low value was used to improve calibration to the measured boron concentrations in
GWA-27BR.
The deep bedrock layer extends about 430 feet (layers 23-28) below the upper bedrock,
and was assigned a uniform value of 0.006 ft/d (Figure 5-6a through Figure 5-6c; Table
5-2). Figure 5-6a and Figure 5-6b show some zones with hydraulic conductivities
higher than the background value. These zones were added to help calibrate hydraulic
heads and boron concentrations observed in wells within layers 20 to 24. Although the
hydraulic conductivity the deep bedrock is generally low, the conductivity is high
enough to allow some water flow in the deep bedrock. Combined with the low rock
porosity (0.01), and the high mobility of boron, this combination results in some deep
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predicted migration of low concentrations of boron beneath the ash basin dams. There
are four bedrock wells located in layers 20 to 24, (GWA-14BR, GWA-31BRA, GWA-
32BR, GWA-33BR, MW-11BRO), where the hydraulic conductivity was adjusted higher
to better match the low hydraulic heads within the wells. Slug tests performed in these
wells indicated high hydraulic conductivity, ranging up to 15 ft/d.
The final calibrated flow model has a mean head residual of -0.19 feet, a root mean
squared error (RMSE) of 4.48 feet, and a normalized root mean square error (NRMSE)
of 2.43 percent. The range of heads at the Site is approximately 184 feet. A comparison
of the observed and simulated water levels is listed in Table 5-1, and the observed and
simulated levels are cross -plotted in Figure 5-7. Table 5-2 lists the best -fit hydraulic
parameters from the calibration effort.
The computed heads in the transition zone (model layer 15) are shown in Figure 5-8.
Figure 5-9 shows the simulated heads in the first fractured bedrock model layer (model
layer 17). These are similar to the shallower heads.
There are two major ridges that cause groundwater flow divides at CSS shown in
Figure 5-10. These groundwater divides separate the Suck Creek drainage basin and
CSS from the surrounding regions. In the southern region between these two
groundwater divides, flow is downgradient toward the Suck Creek drainage (Figure 5-
10). The eastern portion of the area is controlled by the AAB ponded water. Flow into
the AAB ponded water occurs along the south and east edge of the ponded water.
Water flows out on the north and west edge toward Suck Creek and the Broad River
(Figure 5-10). Flow in the western portion between the groundwater divides is
northeasterly toward the Broad River and east toward Suck Creek. Outside of the
groundwater divides surrounding the CSS, flow occurs to the southeast toward
Ashworth Creek, and to the northwest and north toward the Broad River (Figure 5-10).
All flow within the groundwater divides around the CSS discharges to Suck Creek and
the Broad River (Figure 5-10).
The approximate groundwater flow budget for pre -decanted conditions at the CSS site
watershed is shown in Table 5-3. The size of the watershed that contributes to
groundwater flow toward the ash basins depends on the locations of the groundwater
divides that can change over time (for example if the ash basins are excavated or
capped) and that vary with depth. The watershed associated with Suck Creek extends
beyond the model boundary to the south, and only the flow in the model domain is
considered. Under pre -decanting conditions, the watershed area in the model
contributing flow toward the basin is estimated at approximately 1,418 acres. The area
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remaining after removing the AAB, U14 AB, U5 AB, Suck Creek, and the CCR Landfill,
is approximately 1358 acres. The result is approximately 526 gpm of groundwater flow
from recharge. Additional recharge in the AAB adds another 65 gpm of flow. The
creeks, ponds, and wetlands water removes approximately 152 gpm. Suck creek gains
water in the upper reaches, but loses water beyond were it was diverted when the AAB
was built and removes approximately 158 gpm. General head boundaries at the edge of
the model remove 24 gpm. Approximately 246 gpm goes into the Broad River.
5.2 Flow Model Sensitivity Analysis
A parameter sensitivity analysis was performed by varying the main hydraulic
parameters (recharge, ash conductivity, saprolite conductivity, transition zone
conductivity, and upper and lower bedrock conductivity) in the pre -decanting
conditions flow model. Starting with the calibrated model, each parameter was halved
and doubled to evaluate the model sensitivity. Only the main background conductivity
values were varied in this study. Table 5-4 shows the results of the flow parameter
sensitivity study. The model is highly sensitive to the recharge rate, and is moderately
sensitive to the saprolite, transition zone, and bedrock conductivities. The model is
insensitive to ash conductivity. Reducing the conductivity of the deeper bedrock layers
produced a slightly better hydraulic head calibration, but was not consistent with
observed boron transport and hydraulic heads in the new deep bedrock wells.
5.3 Historical Transport Model Calibration
The transient flow model used for transport consisted of a series of six steady-state flow
fields: one that represents the period after the U1-4 AB was built (from 1957 to 1972),
one when to U5 AB began operations (from 1972 to 1975), one after the AAB phase one
was complete, (from 1975 to 1977), one after U14 AB was retired (from 1977 to 1980),
and one after the AAB was expanded to its current footprint (from 1980 to 2019).
The transport simulations used four main spatial zones of specified COI source
concentration associated with the AAB, ASA, U1-4 AB and U5 AB (Figure 5-11; Table 5-
5a through Table 5-5c). The ash basins were then split into sub -zones and were based
on observation wells within and adjacent to the ash basins. The concentration of boron,
sulfate, and TDS was held constant in the ash material in these zones during the
historical transport simulations.
The calibrated Ka values for boron were 0.53 mL/g in the saprolite and transition zone
materials, and 0.02 mL/g in the bedrock. The calibrated Ka values for sulfate were 0.3
mL/g in the saprolite, 0.2 mL/g in transition zone, and 0.01 mL/g in the bedrock. The
calibrated Ka values for sulfate and TDS were 0.15 mL/g in saprolite, 0.15 mL/g in the
transition zone, and 0.01 mL/g in fractured bedrock. The effective porosity was set to
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0.3 in the unconsolidated layers and 0.01 in the bedrock layers. The dry bulk density in
all layers was set to 1.6 g/mL. The dry bulk density is used solely for computation of
the retardation factor in MT3DMS, where it is multiplied by the Ka value.
Table 5-6a through Table 5-6c compare measured (first and second quarter 2019) and
simulated pre -decanting conditions boron, sulfate, and TDS concentrations. The
simulated maximum boron concentrations in all non -ash model layers are shown in
Figure 5-12. This figure of maximum boron is produced by processing the model
results to show the highest concentration in any layer at a given horizontal position
(excluding the ash layers). The future model simulations predict that boron
concentrations greater than 02L standards will be transported within the ASA
predominantly in the saprolite and transition zone. Boron concentrations are predicted
to the west of the AAB upstream dam and north of the AAB downstream dam. This
boron migration appears to mainly occur in saprolite and the transition zone, but
transport in the bedrock is also predicted, including some transport in deeper bedrock.
The eight deep bedrock wells were installed at boring depths of approximately 180 feet
to 400 feet along the dam. Boron was detected in these wells, but at concentrations less
than the 02L groundwater standard of 700 µg/L.
The transport model reflects the following boron observed and simulated values:
• 15 µg/L in well GWA-21BRL (observed value of 230 µg/L)
• 39 µg/L in well GWA-64BRL (observed value of 239 µg/L)
• 0 µg/L in well GWA-65BRL (observed value of 83 µg/L)
• 0 µg/L in well GWA-66BRL (observed value of 385 µg/L)
• 1 µg/L in well GWA-67BRL (observed value of 158 µg/L)
• 0 µg/L in well GWA-68BRL (observed value of 81 µg/L)
Monitoring wells MW-11BRL and GWA-11BRL were not used in in the model
calibration due their inability to provide sufficient water volume for sampling
purposes. Overall, the simulated boron, sulfate, and TDS concentrations appear to
reasonably match the observed concentrations, and the normalized root mean square
error between the observed and predicted boron concentrations is 5.15 percent. The
simulated locations where the COIs exceed the 02L standard is similar to the observed
locations where concentrations were detected at greater than the 02L standard. The
simulated maximum boron concentrations in all non -ash model layers are shown in
Figure 5-13 and Figure 5-14.
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5.4 Transport Model Sensitivity Analysis
A parameter sensitivity analysis was conducted to evaluate the effects of Ka on the
NRMSE. Ka is assumed to be uniform across each grid layer and to vary with depth, as
described in Section 4.6. The sensitivity analysis was performed on the calibrated
transport model by systematically increasing and decreasing boron Ka values by a
factor of 5 from their calibrated values (Section 4.6; Table 5-7). The model was then run
using the revised Ka values, and the NRMSE was calculated and compared to the
NRMSE for the calibrated model.
The most important transport model parameter for boron is the Ka value because the
effective porosity affects transport velocity. The calibrated transport model sensitivity to
the Ka values was evaluated by running the boron transport simulation with Ka values
that were 5 times smaller, and 5 times larger than the calibrated values (0.53 mL/g in
saprolite and transition zone; 0.02 mL/g in bedrock). The results of this analysis are
shown in Table 5-7. The simulation results are sensitive to the Ka value range tested
here, particularly when the Ka value is reduced. The calibrated value produces a
normalized root mean square error of 5.15 percent. This increases to 8.25 percent for low
Ka, and 5.25 percent high Ka cases. In terms of boron plume behavior, the low Ka
simulation over -predicts the extent of boron migration, while the high Ka simulation
under -predicts the extent of boron migration.
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6.0 PREDICTIVE SIMULATIONS OF CLOSURE SCENARIOS
The simulated 2019 boron distribution was used as the initial condition in closure
simulations of future flow and transport at the CSS. There are two simulated closure
scenarios. The scenarios include closure -by -excavation where the ash is excavated and
removed from the ash basins, and closure -in -place where the ash is capped with a final
cover system. In addition, predictive simulations were performed to consider each
closure scenario with active corrective action to achieve 02L compliance.
Decanting of the AAB ponded water began in March 2019. The decanting of the AAB is
required to be completed by March 31, 2020. AAB ponded water decanting will have
an effect on the groundwater flow field because the AAB ponded water level will be
lowered by approximately 66 feet, removing free-standing water.
After the AAB decanting, the basin closure activities will begin and continue for several
years. It is expected that the closure -by -excavation can be completed by 2029, and the
closure -in -place can be completed in by 2026. In both closure scenarios, the ASA is
planned to be excavated as part of the AAB closure activities.
The predictive simulations are run in four steps. The first step is a simulation that uses
the groundwater flow field after the AAB is decanted. The initial boron distribution for
this simulation is simulated with the 2019 concentration distribution. The second
simulation step continues from March 2020 to March 2021, when the ASA is excavated
and regraded. For the third step, another simulation is run from 2021 to 2026, or 2021 to
2029 (for closure -in -place and closure -by -excavation construction to be completed). The
fourth step assumes that construction activities for the closure design and corrective
action measures in the ash basin have been completed and uses the final system flow
field for transport simulations. These simulations start in 2026 or 2029, and continue for
several hundred years.
6.1 Interim Models with Ash Basin Ponded Water Decanted
(2020-2021)
This simulation represents an interim period after the AAB ponded water is decanted,
but before excavation of the ASA is completed. Decanting of the AAB ponded water is
simulated by removing the specified head zone that represents the AAB ponded water
in the pre -decanting conditions flow simulation and replacing it with a small ponded
area within the northern pond and 3 feet above the current top of the ash, an elevation
of 693 feet. Recharge at a rate of 7.5 inches per year is added to the ash basin, and COI
initial conditions come from the historical transport simulation. COI concentrations in
the ash are no longer held constant and can leach from the ash according to the Ka value
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(which was derived from ash leaching tests). COIs present in the underlying soil and
rock are mobile, and move in response to the hydraulics of the groundwater system
with adsorption occurring according to the soil or rock Ka value. The surface drains in
the southern part of the ash basin remain in this simulation. Figure 6-1 shows the
simulated steady-state hydraulic heads after the AAB ponded water is decanted.
Figure 6-2 shows the simulated maximum boron concentrations in all non -ash model
layers in 2020 with the ash basin decanted.
6.2 Interim Period During Construction (2021-2026 or 2021-2029)
The interim simulation begins in 2021 using COI distributions from decanted ponded
water simulations described in the previous section. The excavation ASA design is
based on AECOM designs (Figure 6-3a). In the simulation the ASA is assumed to be
excavated and regraded one year after decanting. Excavation is simulated by setting the
COI concentrations in the ash layers in the ASA to zero. The concentrations of COIs in
the remaining affected soil underneath the ash basin is set to the values from the post -
decanting simulation. The excavated ash layers in the model are given a high hydraulic
conductivity so they do not affect the groundwater flow. Recharge that occurs in the
excavated part of the ASA footprint is set to the background level of 7.5 inches per year.
A small stream network is added to the ASA, following the regraded surface. This
drain network, which connects to the Broad River (Figure 6-3b), simulates a spring and
stream that may form in the regraded ASA.
6.3 Closure -in -Place
Closure -in -place design simulations begin in 2026 using the COI distributions from the
interim simulations described previously. The closure -in -place design is based on a
Closure Plan option developed by AECOM in 2019. This design for the AAB and U5
AB is illustrated in Figure 6-4a and Figure 6-4b (AECOM, 2019).
Following decanting of the AAB ponded water and excavation of the ASA, this design
calls for the AAB upstream dam to be lowered approximately 15 feet, and for the
downstream dam to be regraded to form a gentle slope from west to east. The ash is to
be regraded inside the southern portion of the AAB and will be stacked toward the
center with the highest elevation of approximately 780 feet. The cover system consists
of an impermeable geomembrane covered with approximately 2 feet of soil and a grass
surface. The surface drainage ditches follow along the perimeter of the AAB and
converge into a single channel south of the downstream dam (Figure 6-5). The
groundwater model includes an underdrain, located 5 feet below the ash basin cover
that is located beneath the perimeter surface water drainage ditches.
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The closure -in -place scenario calls for the U5 AB main dam to be lowered, and the ash
will be piled into two separate stacks (AECOM, 2019). A drainage system is proposed
to run along most of the perimeter of the U5 AB and will drain out to the north where
the main dam is located. Underdrains located 5 feet below the cover are included in the
model beneath the surface water drainage system, but they do not remove much water
from the Unit 5 area in the simulations. Figure 6-6 shows the drain network that was
used in the closure -in -place simulation to simulate this underdrain system beneath the
cap.
The closure -in -place is simulated by removing all of the original ash basin surface water
features and replacing them with the underdrain network. Drains were simulated 5
feet below the cap surrounding the perimeter of the AAB and U5 AB. The elevation of
the ditches around the AAB ranges from approximately 770 feet on the southeastern
side of the AAB to approximately 651 feet discharging north toward the Broad River.
The drains in U5 AB range from 785 feet to the southwestern perimeter of the U5 AB to
730 feet to the northwest of U5 AB dam (Figure 6-5). Nodes along the drain arcs are
locations where the drain elevation was specified using the Closure Plan (AECOM,
2019). Drain elevations between these nodes were interpolated along the arcs. The
drains are simulated using the MODFLOW DRAIN feature and a relatively high
conductance of 10.0 ft2/d/ft. Groundwater flow into these drains is removed from the
model. If this closure option is selected, the discharge from the drainage system might
need to be collected, treated, and discharged in accordance with the NPDES permit.
The cover system over the ash is simulated by setting the recharge rate to 0.00054 inches
per year as in the closure -in -place simulation.
The COI concentrations in the ash are variable in time, and the Ka value for boron in the
ash is set to the value measured in ash leaching tests performed with ash from the basin
(0.53 mL/g).
The steady-state hydraulic heads in the transition zone are shown in Figure 6-6. This
design lowers the heads within the AAB and U5 AB. An approximate water balance
was calculated from the closure -in -place flow model. The watershed that contributes
groundwater flow to the CSS site in the model domain is approximately 1418 acres. The
cover over the AAB and U5 AB occupies approximately 172 acres. This results in a net
area of approximately 117 acres that contribute recharge to the groundwater system in
the AAB and U5 area at an average rate of approximately 5 gpm. The underdrain
system beneath the AAB cover removes 47 gpm. The underdrain system beneath the U5
AB cover removes 18 gpm. Creeks, ponds, and streams remove approximately 172
gpm. Suck Creek gains from the watershed 155 gpm. Overall the recharge to the Broad
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River is approximately 154 gpm, which is a reduction by about half of the pre -decanting
conditions simulation. This balance indicates that the deep groundwater flow in the ash
basin area is only a few gpm, which is a reduction by approximately one factor of
nearly half from the pre -decanting conditions simulation.
The simulated maximum boron concentrations in all non -ash model layers are shown 5,
29, 79, 129, and 179 and years after closure -in -place (Figure 6-7a through Figure 6-7e).
The closure -in -place design simulation suggests that boron might continue to migrate
beyond the current 02L boundary north of the AAB toward the ASA for over 100 years
without active remediation. The simulation also suggests that boron might migrate to
the current 02L boundary north of the AAB downgradient of the dam in approximately
80 years.
6.4 Closure -in -Place with Active Remediation
The closure -in -place scenario with active groundwater remediation option to achieve
02L compliance within approximately 6 years is simulated in two steps. The first step
begins in 2021. The flow field that includes the decanted ash basin and the groundwater
remediation system is used for the transport simulation for approximately 5 years
following implementation. After the closure -in -place system has been installed, another
flow field is created and used to run the transport simulation for several hundred years.
The active groundwater remediation systems is primarily implemented within the ASA
(Figure 6-8). The remediation system consists of twenty-three (23) extraction wells
pumping at a total extraction rate of 122 gpm (Table 6-1). Forty-six (46) infiltration wells
along the compliance boundary introduce a total of 139 gpm of clean water to the
system. Nine (9) of the 46 infiltration wells act as a barrier to prevent deep boron
migration north toward the Broad River. The rest of the infiltration wells are simulated
to flush out boron within the vadose zone. A 250 feet horizontal infiltration well
screened at a depth of 10 feet bgs in saprolite is included in the corrective action design.
The horizontal infiltration well introduces 45 gpm of clean water into the vadose zone.
The extraction wells are simulated using a vertical series of MODFLOW DRAIN points.
The DRAIN bottom elevations are set to the center of the gridblock containing the
drain. This simulates a condition where the water is being pumped out of the well
casing to maintain a water level near the bottom of the well. The DRAIN conductance
is estimated by considering radial flow to a well, following Anderson and Woessner
(1992). For a horizontal hydraulic conductivity of K, a well radius of rW, and horizontal
and vertical grid spacing of Ox and Az, the DRAIN conductance for a gridblock is
computed as:
Page 6-4

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
C=
2;TKAz
In 0.208Ax
r
W
(2)
The conductance value is reduced by 50 percent to account for well skin effects.
Infiltration wells are treated similarly, using the General Head (GHB) condition in
MODFLOW, with a conductance calculated the same way, but with a reduction of 75
percent to account for well clogging. The injection heads have been set to 10 feet above
the ground surface.
Figure 6-9a through Figure 6-9e show the maximum boron distribution in all non -ash
layers are shown 5, 29, 79, 129, 179 and 254 years after closure -in -place with preferred
groundwater remediation approach. The remediation system achieves 02L compliance
following approximately 6 years of operation (Figure 6-9a). The simulation also
suggests that boron might migrate tp the current 02L boundary north of the AAB
downgradient of the dam in approximately 80 years. The additional COIs considered,
sulfate and TDS, are shown in Figure 6-10a and Figure 6-10b and are within compliance
five years following operation.
6.5 Closure -by -Excavation
The excavation design involves complete excavation of the ash in the AAB and U5 AB.
The ash will be transported to the CCP Landfill (Figure 6-11). Excavation and
regrading is expected to be completed by 2029. The simulation of excavation with
without active remediation begins in 2029 using the COI distributions from the interim
simulation described here. Excavation is simulated by setting the COI concentrations in
ash layers in the ash basin to 0 µg/L. The concentrations of COIs in the remaining
affected soil underneath the AAB and U5 AB are set to the values from the interim
simulation. The ash layers and dam are given a significantly high hydraulic
conductivity (after excavation), and the previous ash basin surface water features are
removed. Recharge that occurs in the excavated part of the ash basin footprint is set to
the background level of 7.5 inches per year. A small stream network is added to the ash
basin, following the original drainages along the top of the saprolite surface. This drain
network simulates the springs and streams that will form in the basin and connects to
the Broad River (Figure 6-12).
The steady-state hydraulic heads in the transition zone are shown in Figure 6-13. The
groundwater levels are now at or below the original ground surface, and there is a
groundwater divide north of the former Suck Creek channel that is within the AAB. An
approximate water balance was calculated from the excavation flow model. The
watershed that contributes groundwater flow to the basin area increases in size by
Page 6-5

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
approximately 165 acres due to the lower water levels in the former Suck Creek
channel. The net area contributing recharge is approximately 1501 acres. The
watershed recharge contributes approximately 582 gpm. The ponds, creeks, and
wetland areas remove most of the water with 143 gpm. The stream network inside the
AAB removes approximately 114 gpm and the ASA stream network removed
approximately 6 gpm. The U5 AB removes 58 gpm and the general head along the edge
of the model removes 24 gpm. Suck Creek recharges 147 gpm. Therefore, the net deep
groundwater flow is calculated to be 90 gpm.
The simulated boron concentrations for all non -ash layers are shown 8, 29, 79, 129, and
179 years after closure -by -excavation (Figure 6-14a through Figure 6-14e).
6.6 Closure -by -Excavation with Active Remediation
The corrective action for this predictive scenario is the same design considered in
Section 6.4. Since the remediation timeframe occurs during an interim period after the
ASA has been excavated and prior to the completion of the construction of the closure -
by -excavation scenario, the predictive simulation results are similar to what is shown in
Figures 6-14a-e. Figure 6-15 shows the simulated hydraulic heads for the excavation
case with the active corrective action well system. The long-term transport results for
boron are shown in Figure 6-16a through Figure 6-16e. As shown in Figures 6-17a
through 6-17b, sulfate and TDS are also remediated by the corrective action measures
and 02L compliance is achieved in approximately 8 years following operation.
6.7 Conclusions
The following conclusions are based on the results of the groundwater flow and
transport simulations:
• Boron is predicted to be greater than the 02L standard at the current northern
compliance boundary within the ASA for approximately 200 to 300 years for
both closure scenarios without active corrective action.
• The closure -in -place simulation predicts that boron might migrate to the current
02L boundary north of the AAB downgradient of the dam in approximately 80
years.
• The active groundwater remediation approach can be implemented using
conventional techniques with vertical and horizontal wells to reduce COI
concentrations.
• New field data are not likely to change the conclusion that closure -by -excavation
and closure -in -place result in a similar boron transport at the compliance
boundary.
Page 6-6

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
• The simulations indicate that boron, sulfate, and TDS in groundwater could be
less than their respective 02L values beyond the compliance boundary in
approximately 5 years following implementation (closure -in -place) and 8 years
following implementation (closure —by -excavation) by implementing the active
groundwater remediation approach using techniques that are readily available
and accepted in the environmental industry.
• U1-4 AB and U5 AB are addressed in the Tech Memos which can be found in
Appendix G.
Page 6-7

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
7.0 REFERENCES
AECOM, 2019, North Landfill Final Cover Grades, Cliffside Steam Station, Drawing
number 6, July 23, 2019.
Anderson, M.P., and W.W. Woessner, 1992, Applied Groundwater Modeling,
Simulation of Flow and Advective Transport, Academic Press, Inc, New York
NY, 381p.
Daniel, C.C., Douglas G. Smith, and Jo Leslie Eimers, 1997, Hydrogeology and
Simulation of Ground -Water Flow in the Thick Regolith-Fractured Crystalline
Rock Aquifer System of Indian Creek Basin, North Carolina, USGS Water -Supply
2341.
Haven, W. T. 2003. Introduction to the North Carolina Groundwater Recharge Map.
Groundwater Circular Number 19. North Carolina Department of Environment
and Natural Resources. Division of Water Quality, 8 p.
HDR, 2015a. Comprehensive Site Assessment Report, Cliffside Steam Station Ash
Basin, September, 2015.
HDR, 2015b. Corrective Action Plan Part 1. Cliffside Steam Station Ash Basin.
December, 2015.
HDR, 2016. Comprehensive Site Assessment (CSA) Supplement 2, Cliffside Steam
Station, August 11, 2016.
McDonald, M.G. and A.W. Harbaugh, 1988, A Modular Three -Dimensional Finite -
Difference Ground -Water Flow Model, U.S. Geological Survey Techniques of
Water Resources Investigations, book 6, 586 p.
Niswonger, R.G.,S. Panday, and I. Motomu, 2011, MODFLOW-NWT, A Newton
formulation for MODFLOW-2005, U.S. Geological Survey Techniques and
Methods 6-A37, 44-.
North Carolina Water Supply and Use, in "National Water Summary 1987 - Hydrologic
Events and Water Supply and Use". USGS Water -Supply Paper 2350, p. 393-400.
North Carolina; Estimated Water Use in North Carolina, 1995, USGS Fact Sheet FS-087-
97
Radcliffe, D.E., L.T. West, L.A. Morris, and T. C. Rasmussen. 2006. Onsite Wastewater
and Land Application Systems: Consumptive Use and Water Quality, University
of Georgia.
SynTerra, 2017, 2017 Comprehensive Site Assessment Update, October 31, 2017.
Page 7-1

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
SynTerra, 2019a, Ash Basin Pumping Test Report for Cliffside, January 2019.
SynTerra, 2019b, Pumping Test Numerical Simulation Report for Cliffside
Treece, M.W, Jr., Bales, J.D., and Moreau, D.H., 1990, North Carolina water supply and
use, in National water summary 1987 Hydrologic events and water supply and
use: U.S. Geological Survey Water -Supply Paper 2350, p. 393-400.
Wood, 2019, Conceptual Underdrain System Layout, Cliffside Steam Station, 2018
Closure Plan (Draft 100% Permit Set), February 8, 2019.
Zheng, C. and P.P. Wang, 1999, MT3DMS: A Modular Three -Dimensional Multi -
Species Model for Simulation of Advection, Dispersion and Chemical Reactions
of Contaminants in Groundwater Systems: Documentation and User's Guide,
SERDP-99-1, U.S. Army Engineer Research and Development Center, Vicksburg,
MS.
Page 7-2

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
FIGURES

CLOSURE -BY -EXCAVATION AFTER 8 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
♦ T ♦AA AAAAAA
CLOSURE -BY -EXCAVATION AFTER 179 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
i
A'♦ll
r ♦ - ♦♦
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♦ ♦ 1
lAt 2kA
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0-
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LEGEND
EXTRACTION WELL • ASH STORAGE AREA
♦ CLEAN WATER ASH BASIN WASTE
INFILTRATION WELL BOUNDARY
HORIZONTAL CLEAN _ _ _ ASH BASIN COMPLIANCE
WATER INFILTRATION • BOUNDARY
WELL
BORON 700 - 4,000 ug/L
BORON > 4,000 ug/L
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED
ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
CLOSURE -IN -PLACE AFTER 5 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
CLOSURE -IN -PLACE AFTER 179 YEARS
OF ACTIVE GROUNDWATER REMEDIATION
GRAPHIC SCALE
250 0 250 500
(IN FEET)
r 1 • •T`r�
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DATE: 11/20/2019
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DATE: 12/20/2019
ENERGY
APPROVED BY: T. GRANT
DATE: 12/20/2019
PROJECT MANAGER: S. SPINNER
www.svnterracorr).com
FIGURE ES-1
COMPARISON OF SIMULATED MAXIMUM BORON
CONCENTRATIONS IN ALL NON -ASH LAYERS FOR BOTH CLOSURE
SCENARIOS WITH ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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J 1600
21400
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1000
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U
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NAS CHECKED BY: T. GRANT DATE: 12/18/2019 FUNCTIONS OF TIME AT REFERENCE LOCATION 1 FOR CLOSURE -BY -
APPROVED BY: T. GRANT DATE: 12/18/2019 EXCAVATION AND CLOSURE -IN -PLACE WITH ACTIVE
�� PROJECT MANAGER: S. SPINNER GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
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CAROLINAS
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REPORT
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CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
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RUTHERFORD CLEVELAND
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DRAWN BY: J. KIRTZ DATE:06/12/2019
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GRAPHIC SCALE
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synTerra
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(IN FEET)

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LEGEND
--- ASH BASIN WASTE BOUNDARY
- - - ASH BASIN COMPLIANCE BOUNDARY
- - LANDFILL COMPLIANCE BOUNDARY
NOTES:
- - - ASH STORAGE AREA
ALL BOUNDARIES ARE APPROXIMATE.
LANDFILL BOUNDARY
PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
DUKE ENERGY CAROLINAS CLIFFSIDE PLANT SITE BOUNDARY
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
FLOW AND TRANSPORT MODEL BOUNDARY
COORDINATE SYSTEM FIPS 3200 (NAD83).
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NUMERICAL MODEL DOMAIN
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER DATE: 12/15/2019
CHECKED BY: T. GRANT DATE: 12/15/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/15/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET)

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ENERGY.
REVISED BY: W. PRATER
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LEGEND
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SAPROLITE
_ TRANSITION ZONE
UPPER BEDROCK
_ BEDROCK
FIGURE 4-2
FENCE DIAGRAM OF THE 3D HYDROSTRATIGRAPHIC MODEL
USED TO CONSTRUCT THE MODEL GRID
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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410 PROJECT MANAGER: S. SPINNER
synTen-a I
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FIGURE 4-4
HYDRAULIC CONDUCTIVITY ESTIMATED FROM SLUG TESTS PERFORMED IN
COAL ASH AT 14 SITES IN NORTH CAROLINA
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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DATE: 12/12/2019
CHECKED BY: T. GRANT
DATE: 12/12/2019
APPROVED BY: T. GRANT
PROJECT MANAGER: S. SPINNER
DATE: 12/12/2019
www.synterracorp.com
synTen-a
1 10 100
K (ft/d )
• All Piedmont Sites
♦ Cliffside
♦ Model Number
FIGURE 4-5
HYDRAULIC CONDUCTIVITY ESTIMATED FROM SLUG TESTS PERFORMED IN
SAPROLITE AT 10 PIEDMONT SITES IN NORTH CAROLINA
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

1
�:
0.2
0
0.0001
OA*
• All Piedmont Sites
♦ Cliffside
♦ Model Number
0.001 0.01 0.1 1 10 100
DUKE
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DATE: 11/20/2019
--!�
ENERGY
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DATE: 12/12/2019
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DATE: 12/12/2019
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PROJECT MANAGER: S. SPINNER
DATE: 12/12/2019
www.synterracorp.com
WnTen-a
K (ft/d)
FIGURE 4-6
HYDRAULIC CONDUCTIVITY ESTIMATED FROM SLUG TESTS PERFORMED IN
THE TRANSITION ZONE AT 10 PIEDMONT SITES IN NORTH CAROLINA
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

MR11111111
0.2
0
0.0001
• * AAe
0.001 0.01
0.1
K (ft/d )
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DRAWN BY: R. GRAZIANO
DATE: 11/20/2019
"*'ENERGY
REVISED BY: W. PRATER
DATE: 12/12/2019
CHECKED BY: T. GRANT
DATE: 12/12/2019
APPROVED BY: T. GRANT
PROJECT MANAGER: S. SPINNER
DATE: 12/12/2019
www.synterracorp.com
WnTer m
1
10 100
• All Piedmont Sites
♦ Cliffside
♦ Model Number
Each model value
corresponds to main
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FIGURE 4-7
HYDRAULIC CONDUCTIVITY ESTIMATED FROM SLUG TESTS PERFORMED IN
THE BEDROCK AT 10 PIEDMONT SITES IN NORTH CAROLINA
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
FLOW AND TRANSPORT MODEL BOUNDARY
RECHARGE ZONE
ASH BASIN WASTE BOUNDARY
_ - _ ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
ASH STORAGE AREA
k
A`
(� DUKE op
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
P
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/19/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 4-8
DISTRIBUTION OF RECHARGE ZONES
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

J/
\ � i
\ C w
a
o d
LEGEND
f CONSTANT HEAD ZONES
U DRAINS
ASH BASIN WASTE BOUNDARY
— - — ASH BASIN COMPLIANCE BOUNDARY
- — LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
— - — ASH STORAGE AREA
FLOW AND TRANSPORT MODEL BOUNDARY
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
WATER WITHIN THEASH BASIN IS REPRESENTEDAS GENERAL HEADANDASH BASIN
CHANNELS ARE REPRESENTED AS DRAINS.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
0
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER DATE: 12/15/2019
CHECKED BY: T. GRANT DATE: 12/15/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/15/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 4-9
MODEL SURFACE WATER FEATURES
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
DRAINS
GENERAL HEAD ZONES
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
LANDFILL BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
- - - LANDFILL COMPLIANCE BOUNDARY
FLOW AND TRANSPORT MODEL BOUNDARY
"pwiry
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
WATER WITHIN THE ASH BASIN IS REPRESENTED AS GENERAL HEAD AND ASH BASIN
CHANNELS ARE REPRESENTED AS DRAINS.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorD.COM
FIGURE 4-10
MODEL SURFACE WATER FEATURES INSIDE ASH BASIN
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
WATER SUPPLY WELLS
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
LANDFILL BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
- - LANDFILL COMPLIANCE BOUNDARY
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY PROGRESS
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
DUKE ENERGY CAROLINAS CLIFFSIDE PLANT SITE BOUNDARY I COLLECTED ON MAY 8, 2015.
FLOW AND TRANSPORT MODEL BOUNDARY DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIAN0 DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/15/2019
CHECKED BY: T. GRANT DATE: 12/15/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/15/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorD.COM
FIGURE 4-11
WATER SUPPLY WELLS IN MODEL AREA
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
n
#1, 2.0
#2, 200.0
#2, 200.0
m
(� DUKE ` 890
ENERGY®
CAROLINAS synTerrd
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/16/2019
CHECKED BY: T. GRANT DATE: 12/16/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/16/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) I WWW_SVIIYPYYarorD.COfII
FIGURE 5-1a
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 1
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

#2, 200.0
LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#2, 200.0
#2, 200.0
t-
4 K-r�, lt�
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
890 0 890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
1�780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-lb
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 2
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
s #5, 0.07
#211 200.0
#45 0.5
#2, 200.0
#2, 200.0
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
in
890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T.GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW-SVIIYPrrarOY❑-rom
FIGURE 5-1c
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 3
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#4, 0.5
#2, 200.0
#2, 200.0
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
in
890
DRAWN BY: R. GRAZIAN0 DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 5-ld
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 4
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#2, 200
#2, 200
#2, 200
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
in
890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 5-le
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 5
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
u�n n I
#2, 200.0
#2, 200.0
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
890 0 890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
1�780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-lf
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 6
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#2, 200.0
(� DUKE
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
in
890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 5-lg
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 7
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#4, 0.5
(� DUKE
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
in
GRAPHIC SCALE
890 0 890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
1�780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-1h
MODEL HYDRAULIC CONDUCTIVITY ZONES IN ASH
LAYER 8
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

HK The red area represents open
e,0 water in the pond, which is
assigned a conductivity of 200
ft/d. The light green area in
$.0 the dam represents the dam
40 fill which is assigned a value
30 of 0.07 ft/d.
M
0
.
0O01
Feet U.S. Surve
1 0 150 200 250
DUKE DRAWN BY: R. GRAZIANO DATE: 11/20/2019 FIGURE 5-2
ENERGY. REVISED BY: W. PRATER DATE: 12/12/2019 CROSS-SECTION THROUGH ACTIVE ASH BASIN DOWNSTREAM DAM
N►+S CHECKED BY: T. GRANT DATE: 12/12/2019 SHOWING HYDRAULIC CONDUCTIVITY COLORS
APPROVED BY: T. GRANT DATE: 12/12/2019
PROJECT MANAGER: S. SPINNER UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
10 CLIFFSIDE STEAM STATION
SynTeI'Ta www.synterracorp.com
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
rp
FLOW AND TRANSPORT
MODEL BOUNDARY
#8, 3.0
r---�
(� DUKE
ENERGY®
CAROLINAS
41� [ 7--m-
synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
#3, 0.5
Kl0
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 5-3a
MODEL HYDRAULIC CONDUCTIVITY ZONES IN
SAPROLITE LAYER 9
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

Ki
LEGEND
HYDRAULIC CONDUCTIVITY
rp
FLOW AND TRANSPORT
MODEL BOUNDARY
#4, 0.8
Z,.5
Ki
(� DUKE
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
V yn
J
Ki
DRAWN BY: R. GRAZIAN0 DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW-SVIIYPYrar orn-r om
FIGURE 5-3b
MODEL HYDRAULIC CONDUCTIVITY ZONES IN
SAPROLITE LAYER 10
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
rp
FLOW AND TRANSPORT
MODEL BOUNDARY
#9, 4.0
(� DUKE `
ENERGY®
CAROLINAS synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIAN0 DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 5-3c
MODEL HYDRAULIC CONDUCTIVITY ZONES IN
SAPROLITE LAYERS 11 AND 12
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
rp
FLOW AND TRANSPORT
MODEL BOUNDARY
(� DUKE
ENERGY®
CAROLINAS
41�
synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/16/2019
CHECKED BY: T. GRANT DATE: 12/16/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/16/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-3d
MODEL HYDRAULIC CONDUCTIVITY ZONES IN
SAPROLITE LAYER 13
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
EL
FLOW AND TRANSPORT
MODEL BOUNDARY
#5, 0.5 #11, 4.0
(� DUKE
ENERGY
CAROLINAS
#7, 1.0
#5, 0.5 #10, 3.0
#3, 0.1
, 0.5 #10, 3.0
#3, 0.1 #5
#6, 0.8
lll�
synTerra
NOTES:
ALL BOUNDARIES AREAPPROXIMATE.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY
AND HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC
CONDUCTIVITY VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR
MODEL LAYERS ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/16/2019
CHECKED BY: T. GRANT DATE: 12/16/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/16/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD.CORT
FIGURE 5-4a
MODEL HYDRAULIC CONDUCTIVITY ZONES IN TRANSITION
ZONE LAYER 14
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

#2, 0.08
1
LEGEND
HYDRAULIC CONDUCTIVITY
EL
FLOW AND TRANSPORT
MODEL BOUNDARY
#1, 0.04
#1, 0.04
#7, 1.0
#3, 0.1
4
5 DUKE GRAPHIC SCALE
ENERGY ` 890 O 890
CAROLINAS synTerra
(IN FEET)
!01DRAWNBY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/16/2019
CHECKED BY: T. GRANT DATE: 12/16/2019
APPROVED BY: T. GRANT DATE: 12/16/2019
PROJECT MANAGER: S. SPINNER
NOTES: FIGURE 5-4b
ALL BOUNDARIES AREAPPROXIMATE. MODEL HYDRAULIC CONDUCTIVITY ZONES IN TRANSITION
ZONES SHON WERE USED TO DEFINEHYDRAULIC
HORIZONTAL TO VERTICAL ANSOTROPYHORIZONTAL IN THE MODEL. HYYDRAULIICONDUCTIVITY CONDUCTIVITYD ZONE LAYER 15
AVALUES AND RE LISTED IN TABLE b2HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS UPDATED GROUNDWATER FLOW AND TRANSPORT
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9,2019. IMAGE MODELING REPORT
COLLECTED ON MAY 8,2015. CLIFFSIDE STEAM STATION
DRAWING HAS BEEN SET WITH A OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM F PS3200 (NAD83MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
EL
FLOW AND TRANSPORT
MODEL BOUNDARY
#8, 5.0
#9, 8.0
Z
(� DUKE 1";
ENERGY 890
CAROLINAS synTerra ■
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/19/2019
0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorn.com
NOTES: FIGURE 5-4c
ALL BOUNDARIES ARE APPROXIMATE. MODEL HYDRAULIC CONDUCTIVITY ZONES IN TRANSITION
ZONES SHON WERE USED TO DEFINEHYDRAULIC
HORIZONTAL TO VERTICAL ANSOTROPYHORIZONTAL IN THE MODEL. HYYDRAULIICONDUCTIVITY CONDUCTIVITYD ZONE AND FRACTURED BEDROCK LAYER 16
AVALUES AND RE LISTED IN TABLE b2HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS UPDATED GROUNDWATER FLOW AND TRANSPORT
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9,2019. IMAGE MODELING REPORT
COLLECTED ON MAY 8, 2015. CLIFFSIDE STEAM STATION
DRAWING HAS BEEN SET WITH A OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM F PS3200 (NAD83MOORESBORO, NORTH CAROLINA

#4, 0.1
#2, 0.006
LEGEND
DRAWN BY: R. 11111 11 DATE: 11/20/2019
HYDRAULIC CONDUCTIVITY
I'I(
� DUKE `(/
ENERGY®
CAROLINAS synTerra
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET)
www.synterracorp.com
NOTES:
FIGURE 5-5a
ALL BOUNDARIES ARE APPROXIMATE.
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
BEDROCK LAYER 17
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
UPDATED GROUNDWATER FLOW AND TRANSPORT
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9,2019. IMAGE
MODELING REPORT
FLOW AND TRANSPORT
MODEL BOUNDARY
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

#2, o.00s #2, o.00s
#2, 0.006
0
LEGEND
DRAWN BY: R. 1-11 11 DATE: 11/20/2019
HYDRAULIC CONDUCTIVITY
I'I( ��
DUKE `(/
ENERGY® �'
CAROLINAS synTerra
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
PROJECT MANAGER: S. SPINNER
GRAPHIC SCALE
890 0 890 1,780
(IN FEET)
www.synterracori).com
NOTES:
FIGURE 5-5b
ALL BOUNDARIES ARE APPROXIMATE.
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
BEDROCK LAYER 18
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
UPDATED GROUNDWATER FLOW AND TRANSPORT
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9,2019. IMAGE
MODELING REPORT
FLOW AND TRANSPORT
MODELBOUNDARY
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
FLOW AND TRANSPORT
MODEL BOUNDARY
#2, 0.006
(� DUKE
ENERGY®
CAROLINAS
#4, 0.1
#2, 0.006
#2, 0.006
1�7
synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
890 0 890
tot -
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
lkREVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
-. PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracori).com
FIGURE 5-5c
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
BEDROCK LAYER 19
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

#2, 0.006
LEGEND
HYDRAULIC CONDUCTIVITY
�> DUKE
ENERGY®
CAROLINAS Terra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
-
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
-
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
FLOW AND TRANSPORT
1 MODEL BOUNDARY
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
890 0 890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
1�780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-5d
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
BEDROCK LAYER 20
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
3 FLOW AND TRANSPORT
MODEL BOUNDARY
(� DUKE
ENERGY®
CAROLINAS
1�7
synTerra
#1, 0.001
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
890 0 890
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-5e
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
BEDROCK LAYER 21
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
-1 FLOW AND TRANSPORT
MODELBOUNDARY
(� DUKE
ENERGY
CAROLINAS
synTerra
#1, 0.001
NOTES:
ALL BOUNDARIES AREAPPROXIMATE.
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITY AND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.Synterracor�.com
FIGURE 5-5f
MODEL HYDRAULIC CONDUCTIVITY ZONES IN FRACTURED
BEDROCK LAYER 22
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
F7FLOW AND TRANSPORT
MODEL BOUNDARY
(� DUKE
ENERGY
CAROLINAS
NOTES:
ALL BOUNDARIES AREAPPROXIMATE.
#2, 0.006
synTerra
#1, 0.001
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/16/2019
CHECKED BY: T. GRANT DATE: 12/16/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/16/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEETI�www.synterracorp.com
FIGURE 5-6a
MODEL HYDRAULIC CODUCTIVITY ZONES IN DEEP
BEDROCK LAYER 23
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
F7FLOW AND TRANSPORT
MODEL BOUNDARY
(� DUKE
ENERGY
CAROLINAS
NOTES:
ALL BOUNDARIES AREAPPROXIMATE.
#2, 0.006
synTerra
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEETIIwww.synterracorp.com
FIGURE 5-6b
MODEL HYDRAULIC CONDUCTIVITY ZONES IN DEEP
BEDROCK LAYER 24
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
HYDRAULIC CONDUCTIVITY
-1 FLOW AND TRANSPORT
MODELBOUNDARY
(� DUKE
ENERGY
CAROLINAS
NOTES:
ALL BOUNDARIES AREAPPROXIMATE.
#2, o.00s
synTerra
ZONES SHOWN WERE USED TO DEFINE HORIZONTAL HYDRAULIC CONDUCTIVITYAND
HORIZONTAL TO VERTICAL ANISOTROPY IN THE MODEL. HYDRAULIC CONDUCTIVITY
VALUES AND RATIOS OF HORIZONTAL TO VERTICAL ANISOTROPY FOR MODEL LAYERS
ARE LISTED IN TABLE 5-2.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 1 PROJECT MANAGER: S. SPINNER
(IN FEET) I www.synterracorp.com
FIGURE 5-6c
MODEL HYDRAULIC CONDUCTIVITY ZONES IN DEEP
BEDROCK LAYERS 25 - 28
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

:11
tl}
3 750
CL
E
0
CU
700
A-1f
❑
°
+ b- X°
e
0
° .JP+
X❑
.+ +
p a•• o
n®+
o�
+
0
G
❑ G
°
0
650 700 750 800
Line shown is 1:1. Heads are Observed
in feet.
DUKE
ENERGY
DRAWN BY: R. GRAZIANO
REVISED BY: W. PRATER
DATE: 11/20/2019
DATE: 12/12/2019
CHECKED BY: T. GRANT
DATE: 12/12/2019
APPROVED BY: T. GRANT
PROJECT MANAGER: S. SPINNER
DATE: 12/12/2019
tip
www.synterracorp.com
F
synTeaa
FIGURE 5-7
COMPARISON OF OBSERVED AND COMPUTED HEADS FROM THE
CALIBRATED STEADY STATE FLOW MODEL
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
< 9 ft
9-18 ft
- > 18 ft
Ift
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
4PROJDUKE /f1
ENERGY
c synTerra
GRAPHIC SCALE
890 0 890 1,780
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
ECT MANAGER: S. SPINNER
(IN FEET)
www.synterracorp.com
FIGURE 5-8
NOTES:
SIMULATED HYDRAULIC HEADS IN TRANSITION ZONE
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

0
O
s
0 0
..
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
PROJECT MANAGER: S. SPINNER
LEGEND
('
4' ENERGY DUKE
c
`I
synTerra
GRAPHIC SCALE
890 0 890 1,780
(I" FEET)
www.synterracorp.com
FIGURE 5-9
NOTES:
SIMULATED HYDRAULIC HEADS IN FRACTURED BEDROCK
PRIOR TO DECANTING
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
Q
MOORESBORO, NORTH CAROLINA

710 O J/g v ��
// 6g
7a0��Q0 Epp
40 % 0
750
6s0
670 ■ i`
690
670 �
--
m
LEGEND
GROUNDWATER FLOW DIRECTION
DIRECTION OF COI TRANSPORT
GROUNDWATER DIVIDE
HYDRAULIC HEAD (FEET)
ASH BASIN WASTE BOUNDARY
— - — ASH BASIN COMPLIANCE BOUNDARY
- — LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
— - — ASH STORAGE AREA
FLOW AND TRANSPORT MODEL BOUNDARY
(> DUKE lop ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
ARROWS INDICATE INFERRED DIRECTION ONLY, NOT MAGNITUDE.
CONTOUR INTERVAL IS 10 FEET. HEADS ARE SHOWN IN MODEL LAYER 17.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83 AND NAVD88).
DRAWN BY: R. GRAZIAN0 DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) I WWW-SVIIYPrracOY❑-com
FIGURE 5-10
SIMULATED LOCAL ASH BASIN GROUNDWATER FLOW
SYSTEM IN TRANSITION ZONE
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

56
53
54 44
28 48
aF
79
u
a
NOTES:
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
ALL BOUNDARIES ARE
REVISED BY: R. KIEKHAEFER DATE: 12/18/2019
APPROXIMATE.
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019 GRAPHIC SCALE
NUMBER LABELS CORRESPOND
TO CONCENTRATION DATA IN
PROJECT MANAGER: S. SPINNER 475 0 475
TABLE 5-5A-C.
wwws nterracor .com (IN FEET)
AERIAL PHOTOGRAPHY
OBTAINED FROM ESRI ON
DECEMBER 9, 2019. IMAGE
(> DUKE 100,
COLLECTED ON MAY 8, 2015.
4 ENERGY
DRAWING HAS BEEN SET WITH
PROJECTION OF NORTH
synTena
CAROLINASTATE PLANE
COORDINATE SYSTEM FIPS 3200
(NAD83).
FIGURE 5-11
BORON, SULFATE, AND TDS SOURCE ZONES FOR
LEGEND
HISTORICAL TRANSPORT MODEL CALIBRATION
UPDATED GROUNDWATER FLOW AND TRANSPORT
COI SOURCE
MODELING REPORT
ZONES
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
950 1

LEGEND
BORON > 4,000 Ng/L
BORON 700 - 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
- ASH BASIN COMPLIANCE BOUNDARY
- LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
- ASH STORAGE AREA
Tr
.-- -
-,
(> DUKE op
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
Y
lw
12
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
mob REVISED BY: B. ELLIOTT DATE: 12/17/2019
CHECKED BY: T. GRANT DATE: 12/17/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/17/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracori).com
FIGURE 5-12
SIMULATED PRE -DECANTING MAXIMUM BORON
CALIBRATED CONCENTRATIONS IN ALL NON -ASH LAYERS
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
SULFATE > 250 mg/L
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
- — LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
ASH STORAGE AREA
(> DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
�R
A
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/18/2019
CHECKED BY: T. GRANT DATE: 12/18/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/18/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 5-13
SIMULATED PRE -DECANTING MAXIMUM SULFATE
CALIBRATED CONCENTRATIONS IN ALL NON -ASH LAYERS
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
TDS - 500 mg/L
ASH BASIN WASTE BOUNDARY
- ASH BASIN COMPLIANCE BOUNDARY
- LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
- ASH STORAGE AREA
(> DUKE
ENERGY
CAROLINAS
Terra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI
ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
dL
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: B. ELLIOTT DATE: 12/17/2019
CHECKED BY: T. GRANT DATE: 12/17/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/17/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 5-14
SIMULATED PRE -DECANTING MAXIMUM TDS CALIBRATED
CONCENTRATIONS IN ALL NON -ASH LAYERS
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

750 740 710
�60) 710
7g0
750 � � G
g70
�00 • ' 720 \
a
'40
750 `' •
7g0 , 260 ,♦
O � .
O
r
6�0
0
�30
�5o so
LEGEND
HYDRAULIC HEAD (FEET)
PONDED WATER WITHIN ASH BASIN
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
ASH STORAGE AREA
FLOW AND TRANSPORT MODEL BOUNDARY
740�
70
67p w
80 660
• O
1
1 �
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
CONTOUR INTERVAL IS 10 FT.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83 AND NAVD88).
4
1�
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
MEN REVISED BY: D. WHATLEY DATE: 12/17/2019
CHECKED BY: T. GRANT DATE: 12/17/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/17/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 6-1
SIMULATED HYDRAULIC HEADS IN TRANSITION ZONE
LAYER 15 POST -DECANTING
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
BORON > 4,000 Ng/L
BORON 700 - 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
ASH STORAGE AREA
(> DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
It
i
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/17/2019
CHECKED BY: T. GRANT DATE: 12/17/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/17/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.S nterracor .com
FIGURE 6-2
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL
NON -ASH LAYERS AFTER 1 YEAR OF DECANTING
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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DUKE DRAWN BY: R. GRAZIANO DATE: 11/20/2019 FIGURE 6-3a
ENERGY REVISED BY: W. PRATER DATE: 12/18/2019 EXCAVATION CLOSURE DESIGN FOR ASA USED IN BOTH CLOSURE -IN -
CHECKED BY: T. GRANT DATE: 12/18/2019 PLACE AND CLOSURE -BY -EXCAVATION SIMULATIONS
APPROVED BY: T. GRANT DATE: 12/18/2019 (FROM AECOM, 2019)
�� PROJECT MANAGER: S. SPINNER UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
VnTerra I www.synterracorp.com MOORESBORO, NORTH CAROLINA

�♦ �� 69p 710 700
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LEGEND
ASA DRAIN
HYDRAULIC HEAD (FEET)
ASH BASIN WASTE BOUNDARY
- — - ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
- ASH STORAGE AREA
- - ASA EXCAVATION
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
CONTOUR INTERVAL IS 10 FEET.
- AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83 AND NAVD88).
GRAPHIC SCALE
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Jy ■ ■Ted M DRAWN BY: R. GRAZIANO (IN FEET)DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
DUKE
ENERGY . CHECKED BY: T. GRANT DATE: 12/19/2019
APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
/ www.synterracorp.com
FIGURE 6-3b
SIMULATED GROUNDWATER FLOW SYSTEM IN
TRANSITION ZONE AFTER ASA EXCAVATION
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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ENERGY CLOSURE -IN -PLACE CLOSURE DESIGN FOR AAB USED IN SIMULATIONS
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019 (FROM AECOM, 2019)
�� PROJECT MANAGER: S. SPINNER UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
synTerra www.synterracorp.com MOORESBORO, NORTH CAROLINA

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DATE: 11/20/2019
FIGURE 6-4b
■� ENERGY
REVISED BY: W. PRATER
DATE: 12/18/2019
CLOSURE -IN -PLACE CLOSURE DESIGN FOR U5 AB USED IN SIMULATIONS
CHECKED BY: T. GRANT DATE: 12/18/2019
APPROVED BY: T. GRANT DATE: 12/18/2019
PROJECT MANAGER: S. SPINNER
VnTerra www.synterracorp.com
(FROM AECOM, 2019)
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
DRAINS
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
LANDFILL BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
DUKE
ENERGY
CAROLINAS
14'
synTerra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorD.COM
FIGURE 6-5
DRAIN SYSTEM SIMULATED AFTER CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

750 740 710 D
360 710
780 O
�20
750
LEGEND
DRAINS
HYDRAULIC HEAD (FEET)
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
LANDFILL BOUNDARY
— - — ASH BASIN COMPLIANCE BOUNDARY
- — LANDFILL COMPLIANCE BOUNDARY
FLOW AND TRANSPORT MODEL BOUNDARY
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
CONTOUR INTERVAL IS 10 FEET.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83 AND NAVD88).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
OWN REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 6-6
SIMULATED HYDRAULIC HEADS IN TRANSITION ZONE
LAYER 15 FOR CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

11,
♦ L
L
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pool"-
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b.
ti
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/
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LEGEND
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
• ASH BASIN COMPLIANCE BOUNDARY
• LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
• ASH STORAGE AREA
V
(� DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
475
s
f "%L
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW-SVIITP.YYa COYD-(,.om
FIGURE 6-7a
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS AT THE TIME OF CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

:fir♦ I
LEGEND
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
• ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
• ASH STORAGE AREA
(� DUKE
ENERGY
CAROLINAS
Terra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF
NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
W
lk
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.s nterracor .com
FIGURE 6-7b
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 24 YEARS AFTER CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

s: .7
y ♦� rAdbIL,
k �
_3
LEGEND
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
• ASH BASIN COMPLIANCE BOUNDARY
• LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
• ASH STORAGE AREA
091 , �
(� DUKE `'
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 6-7c
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 74 YEARS AFTER CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
BORON 700 - 4,000 Ng/L
_ BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
- ASH BASIN COMPLIANCE BOUNDARY
- LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
- ASH STORAGE AREA
kin,
(> DUKE
ENERGY Terra
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
r
MENOMONEEDRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorD.COM
FIGURE 6-7d
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 124 YEARS AFTER CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
• ASH BASIN COMPLIANCE BOUNDARY
• LANDFILL COMPLIANCE BOUNDARY
LANDFILL BOUNDARY
• ASH STORAGE AREA
(> DUKE
ENERGY
CAROLINAS
Terra
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
r
L
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorp.com
FIGURE 6-7e
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 174 YEARS AFTER CLOSURE -IN -PLACE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

\ 660
♦
♦
D
♦ ,, 710
730
740
rh= t
l
760
OV �$
��.�
��.
,♦,-
S•
w� 4
670
690
LEGEND
♦ CLEAN WATER INFILTRATION WELL
EXTRACTION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
HYDRAULIC HEAD (FEET)
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
- - - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
1 ALL BOUNDARIES ARE APPROXIMATE.
9 CONTOUR INTERVAL IS 10 FEET.
1
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
1 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83 AND NAVD88).
GRAPHIC SCALE
/`-♦`/ry. �. �j 375 0 375 750
Jy ■ ■Ted M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/20/2019
DUKE CHECKED BY: T. GRANT DATE: 12/20/2019
\. . APPROVED BY: T. GRANT DATE: 12/20/2019
ENERGY
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-8
SIMULATED HYDRAULIC HEADS IN TRANSITION ZONE LAYER 15
FOR CLOSURE -IN -PLACE WITH ACTIVE GROUNDWATER
REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
o REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

r
fe o
'
? EXTRACTION WELL
1
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH STORAGE AREA
`
.e
ASH BASIN WASTE BOUNDARY
— - — - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
/`�`/ry. �. 1� 375 0 375 750
Jy ■ ■Ted M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/20/2019
DUKE CHECKED BY: T. GRANT DATE: 12/20/2019
. APPROVED BY: T. GRANT DATE: 12/20/2019
\. ENERGY
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-9a
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 5 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
♦ CLEAN WATER INFILTRATION WELL
' 1
? EXTRACTION WELL
♦ HORIZONTAL CLEAN WATER INFILTRATION WELL
A
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH STORAGE AREA
-- ASH BASIN WASTE BOUNDARY
t + - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
- - ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
- 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
370 0 370 740
s� ■ .Ted M (IN FEET)
.� o DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/20/2019
DUKE CHECKED BY: T. GRANT DATE: 12/20/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/20/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-9b
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 29 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
♦ CLEAN WATER INFILTRATION WELL
1
EXTRACTION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
r (( BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH STORAGE AREA
-- ASH BASIN WASTE BOUNDARY
- - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
375 0 375 750
/`�`/ry. �. 1�
s� M
(IN FEET)
DRAWN BY: R. GRAZIANO
DATE: 11/20/2019
■ ■Ted
REVISED BY: D. WHATLEY
DATE: 12/20/2019
//
r-,, DUKE
CHECKED BY: T. GRANT
DATE: 12/20/2019
APPROVED BY: T. GRANT
DATE: 12/20/2019
\. ENERGY.
PROJECT MANAGER: S. SPINNER
FIGURE 6-9c
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 79 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
1
• ii5 EXTRACTION WELL
1
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700-4,000 Ng/L
BORON > 4,000 Ng/L
ASH STORAGE AREA
—• ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
/`••�`/ry. �. �j 375 0 375 750
Jy ■ ■Ter r M DRAWN BY: R. GRAZIANO (IN FEET)DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/20/2019
DUKE CHECKED BY: T. GRANT DATE: 12/20/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/20/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-9d
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 129 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
1
EXTRACTION WELL
1
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
ASH STORAGE AREA
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
�'-
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
-
SYSTEM RIPS 3200 (NAD83).
- -
GRAPHIC SCALE
375 0 375 750
�
/`�
Teri M (IN FEET)
.`/ry. �,
Jy ■
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
DUKE CHECKED BY: T. GRANT DATE: 12/20/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/20/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-9e
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 179 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

r
LEGEND
EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
SULFATE > 250 mg/L
ASH STORAGE AREA
-- ASH BASIN WASTE BOUNDARY
- - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
375 0 375 750
/`�`/ry. �. �j
M
(�N FEET)
Jy ■ ■Ted
DRAWN BY: R. GRAZIANO
DATE: 11/20/2019
REVISED BY: D. WHATLEY
DATE: 12/19/2019
//
r-,, DUKE
CHECKED BY: T. GRANT
DATE: 12/19/2019APPROVED
BY: T. GRANT
DATE: 12/19/2019
\. ENERGY.
PROJECT MANAGER: S. SPINNER
FIGURE 6-10a
SIMULATED MAXIMUM SULFATE CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -IN -PLACE SCENARIO
AFTER 5 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

-015
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DRAWN BY: R. GRAZIANO
REVISED BY: W. PRATER
DATE: 11/20/2019
DATE: 12/18/2019
CHECKED BY: T. GRANT
DATE: 12/18/2019
APPROVED BY: T. GRANT
MANAGER: S. SPINNER
DATE: 12/18/2019
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www.synterracorp.com
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FIGURE 6-11a
EXCAVATION CLOSURE DESIGN FOR AAB USED IN SIMULATIONS (FROM
WOOD, 2019)
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

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DRAWN BY: R. GRAZIANO DATE: 11/20/2019
FIGURE 6-11b
ENERGY
REVISED BY: W. PRATER DATE: 12/18/2019
EXCAVATION CLOSURE DESIGN FOR U5 AB USED IN SIMULATIONS (FROM
CHECKED BY: T. GRANT DATE: 12/18/2019
WOOD, 2019)
APPROVED BY: T. GRANT DATE: 12/18/2019
PROJECT MANAGER: S. SPINNER
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING REPORT
CLIFFSIDE STEAM STATION
1417
www.synterracorp.com
5yC1TefTa
MOORESBORO, NORTH CAROLINA

LEGEND
DRAINS
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
LANDFILL BOUNDARY
— - — ASH BASIN COMPLIANCE BOUNDARY
- — LANDFILL COMPLIANCE BOUNDARY
FLOW AND TRANSPORT MODEL BOUNDARY
(� DUKE
ENERGY®
CAROLINAS
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
DRAIN NETWORK REPRESENTS SPRINGS AND STREAMS THAT MAY FORM AFTER
EXCAVATION. ELEVATIONS ARE SET TO THE TOP OF SAPROLITE SURFACE, WHICH
CORRESPONDS TO ORIGINAL GROUND SURFACE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
�-r��k • t'a:
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/20/2019
CHECKED BY: T. GRANT DATE: 12/20/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/20/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVIIYPYYacorD.COfII
FIGURE 6-12
SIMULATED DRAIN NETWORK UNDER CLOSURE -BY -
EXCAVATION
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

750 740 710 D
360 710
780 O
�20
750
670
LEGEND
HYDRAULIC HEAD (FEET)
DRAINS
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
LANDFILL COMPLIANCE BOUNDARY
FLOW AND TRANSPORT MODEL BOUNDARY
LANDFILL BOUNDARY
ASH STORAGE AREA
750 60
(� DUKE
ENERGY®
CAROLINAS
0 740
♦�, /\ 720 -_ J1� Inn
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
CONTOUR INTERVAL IS 10 FEET. HEADS ARE SHOWN IN MODEL LAYER 15 AFTER
CLOSURE BY EXCAVATION.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83 AND NAVD88).
660
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
EMINLIL-- REVISED BY: D. WHATLEY DATE: 12/17/2019
CHECKED BY: T. GRANT DATE: 12/17/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/17/2019
890 0 890 1,780 PROJECT MANAGER: S. SPINNER
(IN FEET) WWW_SVI tL-rr'3COYD-r om
FIGURE 6-13
SIMULATED GROUNDWATER FLOW SYSTEM IN TRANSITION
ZONE UNDER CLOSURE -BY -EXCAVATION (MODEL LAYER 15)
UPDATED GROUNDWATER FLOW AND TRANSPORT
MODELING REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
LEGEND
DUKE
475 GRAPHIC SCALE 950 APPROVED BY: T. GRANT DATE: 12/19/2019
�� ENERGY®
PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorl).com
CAROLINAS
synTerm
BORON 700 - 4,000 Ng/L
FIGURE 6-14a
NOTES:
BORON > 4,000 pg/L
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ALL BOUNDARIES ARE APPROXIMATE.
ASH LAYERS AT THE TIME OF CLOSURE -BY -EXCAVATION
ASH BASIN WASTE BOUNDARY
COLLECTED ON MAY 8Y OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
- - - - ASH BASIN COMPLIANCE BOUNDARY
DRAWING HAS BEEN SET WITHA PROJECTION OF NORTH CAROLINASTATE PLANE
REPORT
COORDINATE SYSTEM FIPS 3200(NAD83).
CLIFFSIDE STEAM STATION
— - — - ASH STORAGE AREA
MOORESBORO, NORTH CAROLINA

1;
J
A
LEGEND It
DUKE `►,
ENERGY Sy11TeYrd
BORON 700 - 4,000 Ng/L CAROLINAS
NOTES:
�------ ASH BASIN WASTE BOUNDARY ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
ASH BASIN COMPLIANCE BOUNDARY DRAWING HAS BEEN SET WITHA PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
ASH STORAGE AREA
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019T
GRAPHIC SCALE APPROVED BY: T. GRANDATE: 12/19/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorr).com
FIGURE 6-14b
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 21 YEARS AFTER CLOSURE -BY -EXCAVATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

L1
0
LEGEND
t5 DUKE
��
ENERGY.
CAROLINAS
synTerra
BORON 700 - 4,000 Ng/L
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
ASH BASIN WASTE BOUNDARY
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
• ASH BASIN COMPLIANCE BOUNDARY
DRAWING HAS BEEN SET WITH PROJECTION OF
NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
ASH STORAGE AREA
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/19/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.svnterracorD.COM
FIGURE 6-14c
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 71 YEARS AFTER CLOSURE -BY -EXCAVATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

r i
0.
V �i • ..
1 a
1 -
¢—'
�Il
7-
f9'
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
DUKE
GRAPHIC SCALE
475 G 475 950 APPROVED BY: T. GRANT DATE: 12/19/2019
LEGEND
�� ENERGY®
PROJECT MANAGER: S. SPINNER
CAROLINAS
C1MTL'�
"'JJ �� ��
(IN FEET) www.s nterracor .com
BORON 700 - 4,000 IJg/L
FIGURE 6-14d
NOTES:
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ALL BOUNDARIES ARE APPROXIMATE.
ASH LAYERS 121 YEARS AFTER CLOSURE -BY -EXCAVATION
ASH BASIN WASTE BOUNDARY
AERIAL PHOTOGRAPHY OBTAINED FROM
ESRI ON DECEMBER 9, 2019. IMAGE
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
COLLECTED ON MAY 8, 2015.
REPORT
ASH BASIN COMPLIANCE BOUNDARY
DRAWING HAS BEEN SET WITHA PROJECTION OF NORTH CAROLINASTATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
CiLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
ASH STORAGE AREA

LEGEND
DUKE
t5
ENERGY.
CAROLINAS
s mTem
BORON 700 - 4,000 Ng/L
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
— ASH BASIN WASTE BOUNDARY
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE
COLLECTED ON MAY 8, 2015.
- - - ASH BASIN COMPLIANCE BOUNDARY
DRAWING HAS BEEN SET WITH PROJECTION OF NORTH CAROLINASTATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
— - — - • ASH STORAGE AREA
U
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
CHECKED BY: T. GRANT DATE: 12/19/2019
GRAPHIC SCALE APPROVED BY: T. GRANT DATE: 12/19/2019
475 0 475 950 PROJECT MANAGER: S. SPINNER
(IN FEET) www.synterracorr).com
FIGURE 6-14e
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS 171 YEARS AFTER CLOSURE -BY -EXCAVATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

.'r`.
WAM
\1
co co
LEGEND
♦ CLEAN WATER INFILTRATION WELL
ie EXTRACTION WELL
1 "
o �
HORIZONTAL CLEAN WATER INFILTRATION WELL
o �
HYDRAULIC HEAD (FEET)
ASH STORAGE AREA
moo' ASH BASIN WASTE BOUNDARY
1 O ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
()
�.
1
CONTOUR INTERVAL IS 10 FEET.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
1
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
1
—
SYSTEM FIPS 3200 (NAD83 AND NAVD88).
GRAPHIC SCALE
�
375 0 375 750
synTerra
(IN FEET)
1
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: R. KIEKHAEFER DATE: 12/27/2019
DUKE
CHECKED BY: T. GRANT DATE: 12/27/2019
ENERGY
APPROVED BY: T. GRANT DATE: 12/27/2019
ROJECT MANAGER: S. SPINNER
pwww.synterracorp.com
FIGURE 6-15
SIMULATED HYDRAULIC HEADS IN TRANSITION ZONE LAYER 15
FOR CLOSURE -BY -EXCAVATION WITH ACTIVE
�♦
GROUNDWATER REMEDIATION
�♦
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
�♦
•���_�
REPORT
CLIFFSIDE STEAM STATION
oti°
MOORESBORO, NORTH CAROLINA

r
0
LEGEND
P EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700 - 4,000 Ng/L
BORON > 4,000 Ng/L
S ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM RIPS 3200 (NAD83).
GRAPHIC SCALE
/`-.`/ry. �. �j 370 0 370 740
Jy ■ ■Teri M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/19/2019
DUKE CHECKED BY: T. GRANT DATE: 12/19/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-16a
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 8 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

r
LEGEND
- ie EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
♦ HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700-4,000 Ng/L
BORON > 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
ASH STORAGE AREA
- - - ASH BASIN COMPLIANCE BOUNDARY
� I
W
e
0
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI
ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
375 0 375 750
/`�`/ry. �. �j
M
(IN FEET)
Jy ■ ■Ted
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
REVISED BY: D. WHATLEY DATE: 12/19/2019
//
r-,, DUKE
CHECKED BY: T. GRANT DATE: 12/19/2019
APPROVED BY: T. GRANT DATE: 12/19/2019
\. ENERGY.
PROJECT MANAGER: S. SPINNER
FIGURE 6-16b
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 29 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

4%j din millh:
m t fm
LEGEND
EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
^�! BORON 700 - 4,000 Ng/L
ASH BASIN WASTE BOUNDARY
ASH STORAGE AREA
- - - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
_ AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
R I 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
/rye �� �j 370 0 370 740
sy ■Ted M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/19/2019
DUKE CHECKED BY: T. GRANT DATE: 12/19/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-16c
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 79 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

4%j din millh:
r
LEGEND
♦ CLEAN WATER INFILTRATION WELL
EXTRACTION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700-4000 NG/L
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
_ AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
--- DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
- SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
/rye �� �j 375 0 375 750
sy ■Ted M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/19/2019
DUKE CHECKED BY: T. GRANT DATE: 12/19/2019
\. ENERGY. APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 6-16d
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 129 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

4%j din millh:
t j� r IL
- LEGEND
I
EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
BORON 700 - 4,000 Ng/L
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
t ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM RIPS 3200 (NAD83).
GRAPHIC SCALE
375 0 375 750
/`�.T
`/ry. �. �j
eri M
(IN FEET)
..
Jy ■
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
//
REVISED BY: D. WHATLEY DATE: 12/19/2019
-,.,. DUKE
\. ENERGY.
CHECKED BY: T. GRANT DATE: 12/19/2019
APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
NNW
www.synterracorp.com
FIGURE 6-16e
SIMULATED MAXIMUM BORON CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 179 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
EXTRACTION WELL
♦ CLEAN WATER INFILTRATION WELL
HORIZONTAL CLEAN WATER INFILTRATION WELL
SULFATE > 250 mg/L
ASH BASIN WASTE BOUNDARY
ASH STORAGE AREA
- - - ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
SYSTEM FIPS 3200 (NAD83).
GRAPHICSCALE
375 0
375 750
/`-T
.`/ry. �.j
ed M
(�N FEET)
DRAWN BY: R. GRAZIANO
DATE: 11/20/2019
Jy ■
REVISED BY: D. WHATLEY
DATE: 12/19/2019
r-,, DUKE
CHECKED BY: T. GRANT
DATE: 12/19/2019APPROVED
BY: T. GRANT
DATE: 12/19/2019
\. ENERGY.
PROJECT MANAGER: S. SPINNER
FIGURE 6-17a
SIMULATED MAXIMUM SULFATE CONCENTRATIONS IN ALL NON -
ASH LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO
AFTER 8 YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

LEGEND
EXTRACTION WELL
♦ ♦ CLEAN WATER INFILTRATION WELL
A
�/ HORIZONTAL CLEAN WATER INFILTRATION WELL
TDS > 500 mg/L
ASH STORAGE AREA
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
~' AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 9, 2019. IMAGE COLLECTED ON MAY 8,
r 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE COORDINATE
- SYSTEM RIPS 3200 (NAD83).
GRAPHIC SCALE
/`-.`/ry. �, �j 375 0 375 750
Jy ■ .Teri M (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 11/20/2019
// REVISED BY: D. WHATLEY DATE: 12/19/2019
rDUKE CHECKED BY: T. GRANT DATE: 12/19/2019
ENERGY. APPROVED BY: T. GRANT DATE: 12/19/2019
PROJECT MANAGER: S. SPINNER
FIGURE 6-17b
SIMULATED MAXIMUM TDS CONCENTRATIONS IN ALL NON -ASH
LAYERS FOR THE CLOSURE -BY -EXCAVATION SCENARIO AFTER 8
YEARS OF ACTIVE GROUNDWATER REMEDIATION
UPDATED GROUNDWATER FLOW AND TRANSPORT MODELING
REPORT
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLES

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
AB-01 BROR
713.35
719.01
-5.66
AB-01D
711.24
716.82
-5.58
AB-01S
734.27
729.38
4.89
AB-02BRO
743.19
735.88
7.31
AB-02D
733.84
736.39
-2.55
AB-02S
743.46
737.16
6.30
AB-03BR
757.49
760.01
-2.52
AB-03BRA
760.13
760.27
-0.14
AB-03BRU
745.61
well not used
well not used
AB-03BRUA
755.31
760.38
-5.07
AB-03I
762.84
760.39
2.45
AB-03LA15
762.51
760.26
2.25
AB- 03MA15
762.74
760.24
2.50
AB-03S
762.72
760.71
2.01
AB-03SL
762.8
760.39
2.41
AB-03SLA
762.81
760.35
2.46
AB-04BR
757.33
763.09
-5.76
AB-04D
762.07
763.16
-1.09
AB-04LA15
761.73
763.41
-1.68
AB-04S
761.7
763.39
-1.69
AB-04SL
761.86
763.25
-1.39
AB-04UA15
761.5
763.39
-1.89
AB-05BR
763.06
762.61
0.45
AB-05BRU
764.32
762.39
1.93
AB-05S
763.66
762.25
1.41
AB-06BR
759.19
762.88
-3.69
AB-06D
764.96
762.58
2.38
AB-06S
764.49
762.45
2.04
AB-07BR
760.76
754.85
5.91
AB-07S
761.78
756.67
5.11
AB-08BRU
761.76
755.46
6.30
AB-08I
762.4
755.54
6.86
AB-08S
763.04
755.72
7.32
AB-09BR
758.92
761.42
-2.50
AB-09D
760.82
761.54
-0.72
Page 1

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
AB-09S
760.99
761.65
-0.66
AD 1-01
673.07
669.16
3.91
AD2-01
670.97
668.40
2.57
AD2-02
666.18
666.34
-0.16
AD2-03
668.7
666.49
2.21
AD2-04
668.9
667.76
1.14
AD3-01
668.47
666.41
2.06
AD3-02
667.62
666.04
1.58
AS-01D
I 728.91
731.12
I -2.21
AS-01SB
729.95
731.18
-1.23
AS-02BR
658.86
673.88
-15.02
AS-02D
666.07
672.97
-6.90
AS-02S
673.21
674.30
-1.09
AS-03BRU
704.1
707.10
-3.00
AS-04D CCR
744.9
741.41
3.49
AS-04S
743.91
740.64
3.27
AS-05BR
702.68
701.42
1.26
AS-05BRU
I 699.93
702.50
I -2.57
AS-05S
701.92
702.21
-0.29
AS-06BRA CCR
722.39
725.46
-3.07
AS-06D CCR
721.79
725.10
-3.31
AS-06S CCR
721.97
724.53
-2.56
AS-07BRB
702.24
710.01
-7.77
AS-07D
705.95
709.59
-3.64
AS-071
703.6
705.52
-1.92
AS-07S
710.27
709.17
1.10
AS-08D
I 692.62
695.34
I -2.72
AS-08S
701.64
695.25
6.39
AS-09BR
656.31
well not used
well not used
AS-09D
702.98
701.03
1.95
BG-01BRA
776.9
783.89
-6.99
BG-01D
775.47
782.81
-7.34
BG-01S
774.85
782.67
-7.82
CCPMW-01D
837.36
836.03
1.33
CCPMW-01S
838.67
836.19
2.48
Page 2

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
CCPMW-02D
802.66
805.34
-2.68
CCPMW-02S
804.37
805.39
-1.02
CCPMW-03D
796.33
799.30
-2.97
CCPMW-03S
798.11
799.45
-1.34
CCPMW-04
817.76
822.47
-4.71
CCPMW-05 CCR
816.98
815.67
1.31
CCPMW-06D
815.53
808.78
6.75
CCPMW-06S
815.52
808.85
6.67
CCPTW-01 D
I 808.19
803.38
I 4.81
CCPTW-01S
809.54
803.56
5.98
CCPTW-02
800.07
799.12
0.95
CCR-03BR
725.76
721.62
4.14
CCR-04D
758.39
758.90
-0.51
CCR-05D
758.6
758.60
0.00
CCR-06D
758.96
755.65
3.31
CCR-06S
758.82
755.65
3.17
CCR-07D CAMA
751.77
747.17
4.60
CCR-07S CAMA
I 750.2
747.45
I 2.75
CCR-08BR
762.29
753.80
8.49
CCR-08D
761.46
754.61
6.85
CCR-09D
732.05
729.15
2.90
CCR-11D
730.7
728.75
1.95
CCR-11S
730.32
728.91
1.41
CCR-12BR
738.59
737.76
0.83
CCR-12D
738.88
738.11
0.77
CCR-12S
737.25
738.33
-1.08
CCR-13D CAMA
I 762.74
755.74
I 7.00
CCR-14D
759.94
759.68
0.26
CCR-15D CAMA
763.8
764.41
-0.61
CCR-16D
763.65
763.23
0.42
CCR-16S
763.6
763.22
0.38
CCR-17BR
747.8
737.53
10.27
CCR-CCP-01D
825.18
831.59
-6.41
CCR-CCP-02D
818.4
815.06
3.34
CCR-CCP-03D
807.42
807.81
-0.39
Page 3

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
CCR-CCP-03DA
802.05
807.13
-5.08
CCR-CCP-03S
806.19
807.55
-1.36
CCR-CCP-04D
802.22
803.58
-1.36
CCR-CCP-05D
799.87
801.40
-1.53
CCR-CCP-05S
798.78
801.37
-2.59
CCR-CCP-06D
801.54
802.73
-1.19
CCR-CCP-06S
805.53
802.52
3.01
CCR-CCP-07D
814.58
810.95
3.63
CCR-CCP-08D
I 821.44
816.59
I 4.85
CCR-CCP-09D
811.13
812.82
-1.69
CCR-CCP-09S
810.45
812.82
-2.37
CCR-CCP-10D
807.96
806.32
1.64
CCR-CCP-10DA
812.3
808.18
4.12
CCR-CCP-10S
814.07
806.54
7.53
CCR-CCP-11BR
810.04
811.17
-1.13
CCR-CCP-12D
814.41
810.11
4.30
CCR-CCP-12S
814.77
810.14
4.63
CCR-CCP-13D
I 824
815.63
I 8.37
CCR-CCP-14D
818.8
819.76
-0.96
CCR-CCP-15D
829.55
824.34
5.21
CCR-CCP-15S
833.08
824.31
8.77
CCR-IB-01D CAMA
659.46
662.67
-3.21
CCR-IB-01S CAMA
659.57
662.45
-2.88
CCR-IB-03BR
662.15
660.77
1.38
CCR-IB-03D
659.79
660.46
-0.67
CCR-IB-03S
660.3
660.52
-0.22
CCR-U5-01D
I 739.98
736.93
I 3.05
CCR-U5-02D
708.81
703.44
5.37
CCR-U5-03D CAMA
679.63
680.92
-1.29
CCR-U5-03S CAMA
683.88
682.94
0.94
CCR-U5-04BR
686.95
680.58
6.37
CCR-U5-04D
678.51
679.01
-0.50
CCR-U5-04S
678.44
678.39
0.05
CCR-U5-05D
706.81
707.97
-1.16
CCR-U5-06DA
708.47
710.59
-2.12
Page 4

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
CCR-U5-06S
708.24
709.83
-1.59
CCR-U5-08D
749.78
751.99
-2.21
CCR-U5-08S
750.87
752.27
-1.40
CCR-U5-09S
755.98
758.50
-2.52
CCR-U5-10D
760.42
765.92
-5.50
CCR-U5-10S
760.42
765.98
-5.56
CLMW-01
751.68
748.13
3.55
CLMW-02
689.58
691.52
-1.94
CLMW-03D
727.08
729.88
-2.80
CLMW-03S
727.07
729.48
-2.41
CLMW-04
655.56
660.59
-5.03
CLMW-05S
737.91
732.65
5.26
CLMW-06
766.17
766.59
-0.42
CLP-01
706.69
700.41
6.28
CLP-02
657.15
661.83
-4.68
GWA-01BRU
767.77
764.08
3.69
GWA-02BR
670.39
672.05
-1.66
GWA-02BRA
672.36
671.73
0.63
GWA-02BRU
670.41
671.86
-1.45
GWA-02S
672
671.58
0.42
GWA-03D
696.51
699.30
-2.79
GWA-04D CCR
706.28
707.51
-1.23
GWA-04S CCR
707.66
707.36
0.30
GWA-05BRU
754.83
754.44
0.39
GWA-05S
755.93
754.32
1.61
GWA-06D
768.34
768.65
-0.31
GWA-10D CCR
660.13
659.90
0.23
GWA-10S CCR
660.03
660.09
-0.06
GWA-11BR
661.57
663.12
-1.55
GWA-11 BRL
664.36
666.44
-2.08
GWA-11BRU
658.58
662.53
-3.95
GWA-11S
658.8
662.42
-3.62
GWA-12BRU
681.76
692.00
-10.24
GWA-12S
691.24
692.05
-0.81
GWA-13BR
698.13
706.28
-8.15
Page 5

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
GWA-14BR
686.84
685.37
1.47
GWA-14D
683.38
684.75
-1.37
GWA-14S
685
684.81
0.19
GWA-20BR CCR
728.77
727.93
0.84
GWA-20D CCR
723.55
728.00
-4.45
GWA-20S
727.46
728.04
-0.58
GWA-21BR
670.75
666.06
4.69
GWA-21BRL
673.22
672.90
0.32
GWA-21BRU CCR
I 659.77
664.76
I -4.99
GWA-21S CCR
662.79
664.72
-1.93
GWA-22BRU CCR
654.27
660.38
-6.11
GWA-22S CCR
657.04
660.07
-3.03
GWA-23D
760.87
764.65
-3.78
GWA-24BR
777.5
772.33
5.17
GWA-24D
774.21
773.08
1.13
GWA-24S
773.82
772.56
1.26
GWA-25D
769.32
774.78
-5.46
GWA-25S
I 769.37
774.73
I -5.36
GWA-26D
764.54
764.35
0.19
GWA-26S
764.14
764.36
-0.22
GWA-27BR
757.83
754.88
2.95
GWA-27DA
756.46
756.12
0.34
GWA-28BR
712.22
715.55
-3.33
GWA-28BRU
717.34
717.52
-0.18
GWA- 28S
725.63
717.42
8.21
GWA-29BRA
662.91
659.42
3.49
GWA-29D
I 657.02
660.11
I -3.09
GWA-30BR
771.83
782.18
-10.35
GWA-30BRU
779.29
783.66
-4.37
GWA-30S
781.08
784.32
-3.24
GWA-31BR
746.89
well not used
well not used
GWA-31BRA CCR
696.87
well not used
well not used
GWA-31D CCR
737.87
733.03
4.84
WA- BR
667.91
669.70
-1.79
GWA-32D
668.29
670.94
-2.65
Page 6

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
GWA-33BR
698.51
716.97
-18.46
GWA-33D
716.93
718.25
-1.32
GWA-33S
717.67
718.32
-0.65
GWA-34BR
715.38
well not used
well not used
GWA-34S
707.76
698.60
9.16
GWA-35D
669.97
669.19
0.78
GWA-35S
670.28
669.43
0.85
GWA-36D CCR
702.65
695.60
7.05
GWA-36S CCR
I 700.95
696.47
I 4.48
GWA-37D
672.26
673.30
-1.04
GWA-37S
668.72
673.18
-4.46
GWA-42S
716.3
716.58
-0.28
GWA-43D
706.7
717.93
-11.23
GWA-43S
716.93
718.14
-1.21
GWA-44BR
734.2
729.44
4.76
GWA-44D
726.53
729.54
-3.01
GWA-44S
724.41
729.42
-5.01
GWA-45D
I 753.57
759.72
I -6.15
GWA-47D CCR
756.48
760.24
-3.76
GWA-48BR
775.36
771.73
3.63
GWA-51D
738.87
738.67
0.20
GWA-54BRO
718.86
716.21
2.65
GWA-54D
720.1
717.60
2.50
GWA-54S
718.14
717.40
0.74
GWA-56D
677.13
680.67
-3.54
GWA-56S
678.55
681.19
-2.64
GWA-57BR
I 704.15
well not used
I well not used
GWA-57BRU
699.79
well not used
well not used
GWA-57S
718.92
716.95
1.97
GWA-58BR
706.15
well not used
well not used
GWA-58BRU
716.21
716.65
-0.44
GWA-58S
719.89
716.64
3.25
GWA-59BR
728.79
well not used
well not used
GWA-59D
728.38
well not used
well not used
GWA-60BR
739.54
737.28
2.26
Page 7

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
GWA-60BRU
745.56
736.99
8.57
GWA-6113R
729.28
727.09
2.19
GWA-61BRU
726.99
727.29
-0.30
GWA-62BR
706.7
715.23
-8.53
GWA-62BRU
725.73
well not used
well not used
GWA-63BRU
762.91
759.17
3.74
GWA-63S
764.65
759.50
5.15
GWA-64BRL
717.99
714.79
3.20
GWA-65BR CCR
I 680.78
well not used
I well not used
GWA-65BRL
740.63
726.79
13.84
GWA-66BRL
750.06
737.10
12.96
GWA-67BR
690.33
683.76
6.57
GWA-67BRL
692.88
686.17
6.71
GWA-68BRL
693.74
688.94
4.80
IB-06D
658.03
662.97
-4.94
IB-06S
657.87
662.45
-4.58
IB-07D
661.72
661.70
0.02
IB-07S
I 662.09
661.63
I 0.46
M W-02DA
694.25
692.58
1.67
M W-07D
766.53
756.05
10.48
M W-08D
727.07
727.98
-0.91
MW-08S
730.15
727.82
2.33
MW-10D CCR
758.77
758.41
0.36
MW-10S CCR
758.51
758.33
0.18
MW-11BRL
706.75
717.04
-10.29
MW-11BRO CCR
754.77
735.38
19.39
MW-11DA CCR
I 732.91
735.68
I -2.77
MW-11S
737.06
737.30
-0.24
MW-20D
659.13
665.22
-6.09
MW-20DR CCR
668.86
665.55
3.31
M W-21 BR
762.9
762.38
0.52
M W-21 D
770.65
763.44
7.21
M W-22BR
782.57
781.21
1.36
MW-22DR
782.52
781.60
0.92
MW-23D
716.86
720.57
-3.71
Page 8

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
MW-23DR
717.76
720.43
-2.67
MW-23S
717.2
720.67
-3.47
M W-24D
797.3
800.15
-2.85
M W-24DR
801.01
800.29
0.72
MW-25DR
655.93
661.99
-6.06
MW-30D
789.46
790.35
-0.89
M W-30DA
787.95
790.27
-2.32
M W-30S
790.2
790.33
-0.13
MW-32BR
I 808.14
804.95
I 3.19
MW-32D
806.84
804.99
1.85
M W-32S
808.05
804.82
3.23
MW-34BRU
719.37
719.15
0.22
MW-34S
726.91
719.58
7.33
MW-36BRU
666
667.36
-1.36
M W-36S
667.63
667.23
0.40
M W-38BR
667.41
671.68
-4.27
M W-38D
668.62
671.33
-2.71
MW-38S
I 667.71
671.07
I -3.36
MW-40BRU CCR
704.71
704.99
-0.28
MW-40S CCR
702.85
704.88
-2.03
MW-42DA
774.98
768.19
6.79
M W-42S
774.77
768.08
6.69
SY-01
669.73
667.03
2.70
SY-02
667.01
667.28
-0.27
SY-03
665.71
666.41
-0.70
SY-04
664.64
666.29
-1.65
SY-05
I 667.27
666.55
I 0.72
SY-BG-01
691.41
698.58
-7.17
U5-01D
754.1
756.62
-2.52
U5-01S
754.24
757.21
-2.97
U5-02BR
725.13
728.92
-3.79
U5-02D
727.67
728.03
-0.36
U5-02S-SLA
737.44
728.42
9.02
U5-02S-SLB
742.07
728.86
13.21
U5-04D
702.69
699.99
2.70
Page 9

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-1
OBSERVED, COMPUTED, AND RESIDUAL HEADS FOR THE
CALIBRATED FLOW MODEL
Well
Observed Head
ft
Computed Head
ft
Residual Head
ft
U5-04S
700.53
699.77
0.76
U5-05BR
698.93
704.83
-5.90
U5-05D
704.26
705.52
-1.26
U5-06D
714.54
718.09
-3.55
U5-06S
718.48
717.81
0.67
U5-08BR
763.78
765.15
-1.37
U5-08D
762.04
765.07
-3.03
U5-08S
763.71
765.22
-1.51
Prepared by: RLK Checked by: RAG
Notes•
Ft - feet
Ft. NAVD 88 - North American Vertical Datum of 1988
Page 10

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-2
CALIBRATED HYDRAULIC CONDUCTIVITY PARAMETERS
Hydrostratigraphic
Unit
Model
Layers
Spatial Zones (number
corresponds to Figures
5-1 through 5-7)
Horizontal
Hydraulic
Conductivity
(ft/d)
Anisotropy
Ratio,
Kh:K„
Ash Basin
1-8
#1 coal ash
2.0
10
Ash Basin (pond or
excavated
1-8
#2 ponds in ash basins
200
1
Ash Basin Dam
1-8
#3 ash basin dam
0.1
2
Ash Basin
1-8
#4 ash basin
0.5
5
Ash Basin Dam
1-8
#5 ash basin dam
0.07
5
Ash Basin Dam
1-8
#6 ash basin dam
0.3
5
Sa rolite
9-13
#1
0.1
1
9-13
#2
0.2
1
9-13
#3
0.5
1
9-13
#4
0.8
1
9-13
#5
1.0
1
9-13
#6
1.5
1
9-13
#7
2.0
1
9-13
#8
3.0
1
9-13
#9
4.0
1
9-13
#10
5.0
1
Transition zone
14-15
#1
0.04
1
14-15
#2
0.08
1
14-15
#3
0.1
1
14-15
#4
0.2
1
14-15
#5
0.5
1
14-15
#6
0.8
1
14-15
#7
1.0
1
14-15
#8
1.5
1
14-15
#9
2.0
1
14-15
# 10
3.0
1
14-15
#11
4.0
1
Transition Zone and
16
#1
0.04
1
Fractured Bedrock
16
#2
0.1
1
16
#3
0.5
1
16
#4
0.8
1
16
#5
1.0
1
16
#6
2.0
1
16
#7
4.0
1
16
#8
5.0
1
16
#9
8.0
1
Fractured Bedrock
17-22
#1
0.001
1
17-22
#2
0.006
1
17-22
#3
0.04
1
17-22
#4
0.1
1
17-22
#5
0.3
1
17-22
#6
0.5
1
Page 11

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-2
CALIBRATED HYDRAULIC CONDUCTIVITY PARAMETERS
Hydrostratigraphic
Unit
Model
Layers
Spatial Zones (number
corresponds to Figures
5-1 through 5-7)
Horizontal
Hydraulic
Conductivity
(ft/d)
Anisotropy
Ratio,
Kh:K„
17-22
#7
0.6
1
17-22
#8
0.8
1
17-22
#9
1.0
1
17-22
#10
2.0
1
17-22
#11
3.0
1
17-22
#12
4.0
1
17-22
#13
8.0
1
Bedrock lower
23-28
#1
0.001
1
23-28
#2
0.006
1
23-28
#3
0.01
1
Prepared by: RLK Checked by: RAG
Notes:
ft/d - feet per day
Kh- horizontal hydraulic conductivity
Kn/K - horizontal hydraulic conductivity divided by vertical hydraulic conductivity
Page 12

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-3
WATER BALANCE ON GROUNDWATER SYSTEM PRE -DECANTED
CONDITIONS
Water Balance Components
Flow in
Flow out
(gpm)
(gpm)
Flow from General Head edge of model
24
Direct recharge to watershed outside of ash
basins
526
Surface water and private wells
152
Suck Creek
158
Direct recharge from AAB
65
Direct recharge from U5 AB
0
Prepared by: RLK Checked by: RAG
Notes:
gpm — gallon per minute
Others - groundwater flow in/out of the ash basin flow system that are not included in the above categories
Page 13

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-4
FLOW MODEL SENSITIVITY ANALYSIS
Parameter
Decreased by
Calibrated
Increased by
1/2
2
Regional Recharge (7.5 in/yr)
3.35%
2.43%
3.64%
Saprolite Kh (1-3 ft/d)
2.83%
2.43%
2.61%
TZ Kh (1.0 ft/d)
2.46%
2.43%
2.68%
Upper Bedrock Kh (0.04 ft/d)
2.40%
2.43%
2.64%
Lower Bedrock Kh (0.006
2.40%
2.43%
2.50%
ft/d
Prepared by: RLK Checked by: RAG
Notes•
Parameters are multiplied by 0.5 or 2 and the NRMSE is calculated.
Results are expressed as normalized root mean square error (NRMSE) of the simulated and observed heads.
Kh - horizontal hydraulic
conductivity ft/d - feet per day
Page 14

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5A
ASH BASIN BORON SOURCE CONCENTRATIONS (Ng/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
Boron
1957-2019
1972-2019
1975-2019
U1-4 AB
U5 AB
AAB & ASA
1
--
--
1000
2
--
--
700
3
--
--
700
4
--
--
2280
5
--
--
1700
6
--
--
2000
7
--
--
2280
8
I --
I --
2280
9
--
--
3900
10
--
--
6220
11
--
--
4000
12
--
--
7440
13
--
--
700
14
--
--
3900
15
--
--
4700
16
--
--
3900
17
I --
I --
1160
18
--
--
3200
19
--
--
2280
20
--
--
3900
21
--
--
3000
22
--
--
700
23
--
--
5650
24
--
--
4700
25
--
--
3500
26
I --
I --
1480
27
--
--
5000
28
--
--
117
29
--
--
2000
30
--
--
3000
31
--
--
4500
32
--
--
4400
33
--
--
50
Page 15

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5A
ASH BASIN BORON SOURCE CONCENTRATIONS (Ng/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
Boron
1957-2019
1972-2019
1975-2019
U1-4 AB
U5 AB
AAB & ASA
34
--
--
4800
35
--
--
4500
36
--
--
2280
37
--
--
4700
38
--
--
1050
39
--
--
1050
40
--
--
4500
41
I --
I --
2900
42
--
--
1050
43
--
--
2900
44
--
--
117
45
--
--
2500
46
--
--
2800
47
--
--
2500
48
--
--
1480
49
--
--
2000
50
I --
I --
1050
51
--
--
2500
52
--
--
2500
53
2000
2000
2000
54
300
300
300
55
400
400
400
56
400
1 400
400
57
--
2500
2500
58
--
300
300
59
I --
I 300
300
60
--
2500
2500
61
--
300
300
62
--
500
500
63
--
300
300
64
--
300
300
65
--
300
300
Revised by: RLK Checked by: RAG
Page 16

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5B
ASH BASIN SULFATE SOURCE CONCENTRATIONS (mg/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
Sulfate
1957-1972
U1-4 AB
1972-1975
U5 AB
1975-2019
AAB & ASA
1
--
--
50
2
--
--
50
3
--
--
50
4
--
--
300
5
--
--
50
6
--
--
50
7
--
--
300
8
--
I --
I 300
9
--
--
300
10
--
--
150
11
--
--
300
12
--
--
100
13
--
--
50
14
--
--
300
15
--
--
300
16
--
--
300
17
--
I --
I 50
18
--
--
100
19
--
--
250
20
--
--
300
21
--
--
518
22
--
--
300
23
--
--
100
24
--
--
619
25
--
--
300
26
--
I --
I 516
27
--
--
50
28
--
--
100
29
--
--
260
30
--
--
100
31
--
--
50
32
--
--
300
33
--
--
300
Page 17

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5B
ASH BASIN SULFATE SOURCE CONCENTRATIONS (mg/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
Sulfate
1957-1972
U1-4 AB
1972-1975
U5 AB
1975-2019
AAB & ASA
34
--
--
300
35
--
--
300
36
--
--
250
37
--
--
300
38
--
--
300
39
--
--
300
40
--
--
834
41
--
I --
I 200
42
--
--
834
43
--
--
340
44
--
--
250
45
--
--
100
46
--
--
340
47
--
--
200
48
--
--
100
49
--
--
300
50
--
I --
I 200
51
--
--
200
52
--
--
100
53
300
300
300
54
150
150
150
55
400
400
400
56
400
400
1 400
57
--
2500
2500
58
--
300
300
59
--
I 300
I 300
60
--
100
100
61
--
400
400
62
--
300
300
63
300
300
64
300
300
65
--
150
150
Revised by: RLK Checked by: RAG
Page 18

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
ASH BASIN TDS SOURCE CONCENTRATIONS (mg/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
TDS
1957-1972
U1-4 AB
1972-1975
U5 AB
1975-2019
AAB & ASA
1
--
--
300
2
--
--
400
3
--
--
300
4
--
--
500
5
--
--
300
6
--
--
300
7
--
--
500
8
--
I --
I 500
9
--
--
500
10
--
--
500
11
--
--
500
12
--
--
300
13
--
--
300
14
--
--
500
15
--
--
500
16
--
--
500
17
--
I --
I 300
18
--
--
500
19
--
--
526
20
--
--
500
21
--
--
1170
22
--
--
500
23
--
--
500
24
--
--
1070
25
--
--
500
26
--
I --
I 1100
27
--
--
500
28
--
--
300
29
--
--
500
30
--
--
500
31
--
--
500
32
--
--
500
33
--
--
500
Page 19

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
ASH BASIN TDS SOURCE CONCENTRATIONS (mg/L) USED IN
HISTORICAL TRANSPORT MODEL
Polygon
TDS
1957-1972
U1-4 AB
1972-1975
U5 AB
1975-2019
AAB & ASA
34
--
--
500
35
--
--
500
36
--
--
750
37
--
--
500
38
--
--
500
39
--
--
500
40
--
--
1710
41
--
I --
I 500
42
--
--
500
43
--
--
700
44
--
--
300
45
--
--
0
46
--
--
700
47
--
--
500
48
--
--
1100
49
--
--
500
50
--
I --
I 500
51
--
--
500
52
--
--
0
53
500
500
500
54
500
500
500
55
400
400
400
56
400
400
400
57
--
2500
2500
58
--
300
300
59
--
I 300
I 300
60
--
100
100
61
--
400
400
62
--
300
300
63
--
300
300
64
--
500
500
65
--
500
500
Prepared by: RLK Checked by: RAG
Notes:
Location of each source zone is identified in Figure 5-11
Page 20

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
AB-01BROR
385
653
AB-01D
1160
857
AB-01S
0
619
AB-02BRO
503
806
AB-02D
334
1005
AB-02S
300
2500
AB-03BR
46
0
AB-03BRA
34
1
AB-03BRUA
66
1
AB-03I
47
141
AB-03MA15
1660
2217
AB-03S
2660
2280
AB-03SL
1170
2217
AB-04BR
55
6
AB-04D
35
457
AB-04LA15
488
2223
AB-04S
2600
2280
AB-04SL
1980
2223
AB-04UA15
2970
2280
AB-05BR
0
1
AB-05BRU
0
-13
AB-05S
5650
5650
AB-06BR
0
638
AB-06D
0
47
AB-06S
7440
7440
AB-07BR
93
14
AB-07BRU
90
11
AB-07S
1630
2650
AB-08BR
341
598
AB-08BRU
459
1746
AB-08I
807
2748
AB-08S
4330
4500
AB-09BR
0
0
AB-09D
73
0
AB-09S
6220
6220
AS-01D
679
642
AS-01SB
1620
1353
Page 21

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
AS-02BR
480
94
AS-02D
340
157
AS-02S
556
371
AS-03BRU
0
0
AS-04D
0
0
AS-04S
0
0
AS-05BR
0
0
AS-05BRU
0
0
AS-05S
0
0
AS-06BRA
0
0
AS-06D
0
0
AS-06S
0
0
AS-07BRB
79
337
AS-07D
836
624
AS-07I
607
214
AS-07S
1480
1480
AS-08BR
34
296
AS-08D
776
454
AS-08S
117
1067
AS-09BR
0
135
AS-09D
171
401
BG-01BRA
0
0
BG-01D
0
0
BG-01S
0
0
BG-02D
25
0
CCPMW-01D
0
0
CCPMW-01S
0
0
CCR-03BR
6
248
CCR-04D
50
87
CCR-05D
77
12
CCR-06D
1430
455
CCR-06S
1460
3898
CCR-07D
628
810
CCR-07S
2960
3175
CCR-08BR
955
657
CCR-08D
1550
1711
CCR-09D
903
1057
Page 22

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
CCR-11D
1160
1310
CCR-11S
869
789
CCR-12BR
26
247
CCR-12D
301
691
CCR-12S
1110
903
CCR-13D
0
0
CCR-14D
1100
1792
CCR-15D
107
338
CCR-16D
41
0
CCR-16S
3080
1745
CCR-17BR
0
18
CCR-IB-01D
30
4
CCR-IB-01S
157
273
CCR-IB-03BR
0
2
CCR-IB-03D
67
26
CCR-IB-03S
336
147
CCR-U5-01D
6
167
CCR-U5-02D
83
63
CCR-U5-03D
132
153
CCR-U5-03S
32
137
CCR-U5-04BR
488
114
CCR-U5-04D
784
856
CCR-U5-04S
602
689
CCR-U5-05D
426
286
CCR-U5-06DA
182
250
CCR-U5-06S
176
264
CCR-U5-08D
195
93
CCR-U5-08S
17
299
CCR-U5-09S
400
328
CCR-U5-10D
9
1
CCR-U5-10S
5
14
CLMW-01
1360
2375
CLMW-02
589
620
CLMW-03D
923
659
CLMW-03S
903
682
CLMW-04
58
322
CLMW-05S
0
771
Page 23

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
CLMW-06
0
12
CLP-01
204
444
CLP-02
47
455
GWA-01BRU
0
0
GWA-02BR
100
76
GWA-02BRA
83
61
GWA-02BRU
132
93
GWA-02S
112
130
GWA-03D
397
249
GWA-04D
167
96
GWA-04S
168
237
GWA-05BRU
32
20
GWA-05S
0
124
GWA-06D
0
0
GWA-06S
0
0
GWA-10D
0
16
GWA-10S
81
142
GWA-11BR
216
1
GWA-11BRL
29
0
GWA-11BRU
285
40
GWA-11S
416
534
GWA-12BRU
0
0
GWA-12S
0
1
GWA-13BR
79
0
GWA-14BR
0
0
GWA-14D
96
0
GWA-14S
63
1
GWA-20BR
359
1030
GWA-20D
1010
1762
GWA-20S
379
1181
GWA-21BR
114
238
GWA-21BRL
230
15
GWA-21BRU
158
535
GWA-21S
96
331
GWA-22BRU
0
251
GWA-22S
250
264
GWA-23D
0
6
Page 24

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
GWA-24BR
0
0
GWA-24D
0
0
GWA-24S
45
0
GWA-25D
0
0
GWA-25S
0
1
GWA-26D
0
0
GWA-26S
0
9
GWA-27BR
224
1038
GWA-27DA
992
1154
GWA-28BR
0
186
GWA-28BRU
0
93
GWA-28S
0
1
GWA-29BRA
0
0
GWA-29D
0
1
GWA-30BR
0
0
GWA-30BRU
28
0
GWA-30S
0
0
GWA-31BRA
28
77
GWA-31D
35
177
GWA-32BR
0
0
GWA-32D
0
0
GWA-33BR
199
0
GWA-33D
0
0
GWA-33S
25
0
GWA-34BR
0
24
GWA-34S
0
13
GWA-35D
107
51
GWA-35S
101
81
GWA-36D
177
61
GWA-36S
88
103
GWA-37D
64
61
GWA-37S
72
101
GWA-38D
0
0
GWA-38S
120
0
GWA-39S
1620
892
GWA-42S
29
260
GWA-43D
36
0
Page 25

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
GWA-43S
67
0
GWA-44BR
46
0
GWA-44D
39
0
GWA-44S
32
0
GWA-45D
0
0
GWA-45S
0
0
GWA-47D
390
10
GWA-48BR
0
0
GWA-51D
750
577
GWA-54BRO
91
54
GWA-54D
86
93
GWA-54S
91
1
GWA-56D
0
0
GWA-56S
39
0
GWA-57BR
228
54
GWA-57BRU
59
9
GWA-57S
0
6
GWA-58BR
339
143
GWA-58BRU
0
81
GWA-58S
0
39
GWA-59BR
579
38
GWA-59D
503
58
GWA-60BR
0
0
GWA-60BRU
0
0
GWA-61 BR
39
0
GWA-61 BRU
0
0
GWA-62BR
361
0
GWA-62BRU
74
0
GWA-63BRU
98
41
GWA-63S
0
291
GWA-64BRL
239
39
GWA-65BR
415
731
GWA-65BRL
83
0
GWA-66BRL
395
0
GWA-67BR
18
47
GWA-67BRL
158
1
GWA-6813RL
81
0
Page 26

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(N9/L)
Computed Boron
(N9/L)
IB-01D
0
1
IB-01S
165
282
IB-02AL
490
40
IB-02BRU
0
1
IB-02I
99
1
IB-02S-SL
240
400
IB-03D
357
3
IB-03S
880
760
IB-04BR
57
0
IB-04D
44
0
IB-04S-SL
390
650
IB-06D
116
3
IB-06S
838
30
IB-07D
0
14
IB-07S
212
256
MW-02DA
0
71
MW-04D
81
521
MW-08D
138
1869
M W-08S
151
776
MW-10D
142
0
MW-10S
256
0
MW-11BRL
51
43
MW-11BRO
97
736
MW-11DA
84
537
MW-11S
813
386
MW-20D
205
417
MW-20DR
174
632
MW-21BR
0
0
MW-21D
0
0
MW-22BR
0
0
MW-22DR
0
0
MW-23D
51
0
MW-23DR
0
0
MW-23S
26
0
MW-24D
0
0
MW-24DR
0
0
MW-25DR
0
0
Page 27

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6A
COMPARISON OF OBSERVED AND SIMULATED BORON
CONCENTRATIONS (pg/L) IN MONITORING WELLS
Well
Observed Boron
(pg/L)
Computed Boron
(pg/L)
MW-30D
0
0
MW-30DA
0
0
MW-30S
0
0
MW-32BR
0
0
MW-32D
0
0
MW-32S
0
0
MW-34BRU
0
18
MW-34S
0
4
MW-36BRU
0
12
MW-36S
42
4
MW-38BR
45
140
MW-38D
226
25
MW-38S
163
59
MW-40BRU
0
0
MW-40S
29
2
MW-42DA
0
0
MW-42S
0
0
U5-01D
0
32
U5-01S
0
122
U5-02BR
88
70
U5-02D
130
154
U5-02S-SLA
288
300
U5-02S-SLB
278
300
U5-03D
124
155
U5-04BRA
0
3
U5-04D
0
17
U5-04S
275
123
U5-05BR
538
230
U5-05D
216
496
U5-06D
180
241
U5-06S
158
300
U5-07D
141
12
U5-07S
179
300
U5-07SL
180
247
U5-0813R
27
0
U5-08D
39
1
U5-08S
29
300
Notes:
Data collected through April 2019.
Page 28

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
AB-01 BROR
11
47
AB-01 D
45
46
AB-01S
3
27
AB-02BRO
61
186
AB-02D
53
157
AB-02S
59
100
AB-03BR
127
0
AB-03BRA
128
1
AB-03BRUA
100
2
AB-03I
3
73
AB-03MA15
112
249
AB-03S
250
250
AB-03SL
71
249
AB-04BR
4
7
AB-04D
0
123
AB-04LA15
1
248
AB-04S
149
250
AB-04SL
47
248
AB-04UA15
149
250
AB-05BR
6
2
AB-05BRU
6
3
AB-05S
78
100
AB-06BR
6
136
AB-06D
1
33
AB-06S
79
100
AB-07BR
4
13
AB-07BRU
8
10
AB-07S
84
140
AB-08BR
7
173
AB-08BRU
8
407
AB-08I
19
650
AB-08S
834
834
AB-09BR
14
0
AB-09D
2
0
AB-09S
138
150
AS-01D
61
179
Page 29

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
AS-01SB
260
250
AS-02BR
95
58
AS-02D
213
86
AS-02S
194
137
AS-03BRU
0
0
AS-04D
1
0
AS-04S
3
0
AS-05BR
3
0
AS-05BRU
0
0
AS-05S
0
0
AS-06BRA
3
0
AS-06D
1
0
AS-06S
1
0
AS-07BRB
38
95
AS-07D
126
160
AS-07I
208
122
AS-07S
516
516
AS-08BR
62
105
AS-08D
209
139
AS-08S
24
150
AS-09BR
6
51
AS-09D
3
95
BG-01BRA
15
0
BG-01D
2
0
BG-01S
0
0
BG-02D
11
0
CCPMW-01D
1
0
CCPMW-01S
0
0
CCR-03BR
7
23
CCR-04D
18
8
CCR-05D
29
3
CCR-06D
198
101
CCR-06S
619
487
CCR-07D
37
156
CCR-07S
518
322
CCR-08BR
60
312
CCR-08D
340
386
Page 30

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
CCR-09D
339
99
CCR-11D
100
155
CCR-11S
97
53
CCR-12BR
16
200
CCR-12D
22
246
CCR-12S
43
92
CCR-13D
3
0
CCR-14D
67
26
CCR-15 D
0
76
CCR-16D
3
0
CCR-16S
82
154
CCR-17BR
7
4
CCR-IB-01D
15
2
CCR-IB-01S
149
106
CCR-IB-03BR
1410
2
CCR-IB-03D
95
23
CCR-IB-03S
232
131
CCR-U5-01D
60
88
CCR-U5-02D
43
25
CCR-U5-03D
70
77
CCR-U5-03S
24
75
CCR-U5-04BR
279
47
CCR-U5-04D
304
201
CCR-U5-04S
196
105
CCR-U5-05D
151
150
CCR-U5-06DA
221
145
CCR-U5-06S
177
151
CCR-U5-08D
445
44
CCR-U5-08S
201
476
CCR-U5-09S
5
326
CCR-U5-10D
15
0
CCR-U5-10S
0
4
CLMW-01
105
221
CLMW-02
250
129
CLMW-03D
293
163
CLMW-03S
253
132
CLMW-04
0
21
Page 31

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
CLMW-05S
4
35
CLM W-06
0
74
CLP-01
14
65
CLP-02
18
25
GWA-01BRU
8
1
GWA-02BR
69
42
GWA-02BRA
50
36
GWA-02BRU
67
53
GWA-02S
48
64
GWA-03D
175
132
GWA-04D
242
76
GWA-04S
209
151
GWA-05BRU
48
37
GWA-05S
504
103
GWA-06D
1
0
GWA-06S
7
0
GWA-10D
22
16
GWA-10S
92
143
GWA-11 BR
72
0
GWA-11BRU
11
0
GWA-11S
92
17
GWA-12BRU
112
219
GWA-12S
8
0
GWA-13BR
18
0
GWA-14BR
103
0
GWA-14D
25
0
GWA-14S
149
0
GWA-20BR
85
0
GWA-20D
87
182
GWA-20S
186
103
GWA-21 BR
92
51
GWA-21BRL
0
23
GWA-21 BRU
2
6
GWA-21S
26
35
GWA-22BRU
122
23
GWA-22S
4
12
GWA-23D
3
11
Page 32

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
GWA-24BR
1
1
GWA-24D
7
0
GWA-24S
3
0
GWA-25D
0
0
GWA-25S
8
0
GWA-26D
0
3
GWA-26S
46
0
GWA-27BR
0
1
GWA-27DA
6
27
GWA-28BR
61
20
GWA-28BRU
5
16
GWA-28S
11
10
GWA-29BRA
1
0
GWA-29D
10
0
GWA-30BR
7
1
GWA-30BRU
14
0
GWA-30S
63
0
GWA-31BRA
0
0
GWA-31 D
87
127
GWA-32BR
300
197
GWA-32D
8
0
GWA-33BR
3
0
GWA-33D
97
0
GWA-33S
93
0
GWA-34BR
96
0
GWA-34S
30
15
GWA-35D
6
10
GWA-35S
53
52
GWA-36D
22
35
GWA-36S
319
99
GWA-37D
87
75
GWA-37S
292
73
GWA-38D
66
83
GWA-38S
16
0
GWA-42S
171
0
GWA-43D
416
51
GWA-43S
49
22
Page 33

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
GWA-44BR
92
0
GWA-44D
47
0
GWA-44S
334
0
GWA-45D
291
0
GWA-45S
445
0
GWA-47D
27
0
GWA-48BR
44
0
GWA-51D
0
2
GWA-54BRO
12
0
GWA-54D
199
89
GWA-54S
110
39
GWA-56D
60
40
GWA-56S
0
1
GWA-57BR
118
0
GWA-57BRU
142
0
GWA-57S
93
21
GWA-58BR
184
4
GWA-58BRU
99
1
GWA-58S
98
52
GWA-59BR
239
44
GWA-59D
245
5
GWA-60BR
138
35
GWA-60BRU
143
24
GWA-61BR
142
0
GWA-61 BRU
444
0
GWA-62BR
272
0
GWA-62BRU
358
0
GWA-63BRU
172
0
GWA-63S
8
34
GWA-64BRL
1
91
GWA-65BR
28
9
GWA-65BRL
112
164
GWA-66BRL
19
2
GWA-67BR
79
2
GWA-67BRL
98
0
GWA-68BRL
44
1
IB-01 D
433
291
Page 34

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
IB-01S
83
16
IB-02AL
32
0
IB-02BRU
52
0
IB-02I
269
269
IB-02S-SL
81
2
IB-03D
238
295
IB-03S
40
1
IB-04BR
34
1
IB-04D
153
252
IB-04S-SL
49
1
IB-06D
308
12
IB-06S
44
8
IB-07D
114
160
IB-07S
25
57
M W-02DA
17
34
MW-04D
55
139
MW-08D
48
32
MW-08S
14
0
MW-10D
65
0
MW-10S
8
34
MW-11BRO
24
22
MW-11DA
43
13
MW-11S
6
19
MW-20D
0
28
MW-20DR
7
0
MW-21BR
1
0
MW-21D
9
0
MW-22BR
2
0
MW-22DR
335
0
MW-23D
26
0
MW-23DR
97
0
MW-23S
1
0
MW-24D
10
0
MW-24DR
1
0
MW-25DR
16
0
MW-30D
13
0
MW-30DA
0
0
Page 35

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-6B
COMPARISON OF OBSERVED AND SIMULATED SULFATE
CONCENTRATIONS (mg/L) IN MONITORING WELLS
Well
Observed Sulfate
(mg/L)
Computed Sulfate
(mg/L)
MW-30S
16
0
MW-32BR
6
0
MW-32D
0
0
MW-32S
12
16
MW-34BRU
0
3
MW-34S
8
14
MW-36BRU
7
4
MW-36S
222
86
MW-38BR
239
48
M W-38D
180
43
MW-38S
116
1
MW-40BRU
125
3
M W-40S
110
0
M W-42DA
44
0
MW-42S
3
15
U5-01D
2
60
U5-01S
16
34
U5-02BR
98
76
U5-02D
116
150
U5-02S-SLA
150
150
U5-02S-SLB
51
79
U5-03D
48
2
U5-0413RA
18
3
U5-04D
68
12
U5-04S
45
82
U5-05BR
456
108
U5-05D
104
197
U5-06D
198
124
U5-06S
167
151
U5-07D
229
15
U5-07S
35
150
U5-07SL
258
123
U5-08BR
35
0
U5-08D
2
3
U5-08S
25
150
Notes•
Data collected through April 2019.
Prepared by: RLK Checked by: RAG
Page 36

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
AB-01BROR
361
372
AB-01D
345
313
AB-01S
97
166
AB-02BRO
295
470
AB-02D
244
371
AB-02S
167
0
AB-03BR
2860
3
AB-03BRA
2980
11
AB-03BRUA
588
19
AB-03I
80
332
AB-03MA15
310
747
AB-03S
750
750
AB-03SL
188
747
AB-04BR
112
29
AB-04D
28
344
AB-04LA15
54
524
AB-04S
461
526
AB-04SL
159
524
AB-04UA15
526
526
AB-05BR
38
8
AB-05BRU
34
14
AB-05S
403
500
AB-06BR
88
342
AB-06D
32
118
AB-06S
350
300
AB-07BR
176
60
AB-07BRU
217
48
AB-07S
333
561
AB-08BR
231
398
AB-08BRU
243
879
AB-08I
191
1375
AB-08S
1710
1710
AB-09BR
138
0
AB-09D
57
2
AB-09S
429
500
AS-01 D
169
481
AS-01SB
491
576
Page 37

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
AS-02BR
310
232
AS-02D
485
339
AS-02S
365
430
AS-03BRU
36
2
AS-04D
41
0
AS-04S
71
0
AS-05BR
66
1
AS-05BRU
1
2
AS-05S
1
0
AS-06BRA
89
0
AS-06D
43
0
AS-06S
25
0
AS-07BRB
165
247
AS-07D
308
425
AS-07I
433
368
AS-07S
1100
1100
AS-08BR
244
286
AS-08D
421
383
AS-08S
188
850
AS-09BR
122
134
AS-09D
74
290
BG-01BRA
212
0
BG-01 D
48
0
BG-01S
45
0
BG-02D
137
0
CCPMW-01D
34
0
CCPMW-01S
1
0
CCR-03BR
98
168
CCR-04D
54
70
CCR-05D
136
6
CCR-06D
420
211
CCR-06S
1070
851
CCR-07D
137
471
CCR-07S
1170
631
CCR-08BR
222
817
CCR-08D
688
824
CCR-09D
614
159
Page 38

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
CCR-11D
361
352
CCR-11S
378
86
CCR-12BR
159
345
CCR-12D
164
445
CCR-12S
163
151
CCR-13D
32
1
CCR-14D
279
280
CCR-15D
39
151
CCR-16D
64
0
CCR-16S
138
258
CCR-17BR
62
43
CCR-IB-01D
90
4
CCR-IB-01S
292
186
CCR-IB-03BR
2190
3
CCR-IB-03D
450
41
CCR-IB-03S
563
223
CCR-U5-01D
159
290
CCR-U5-02D
96
70
CCR-U5-03D
190
252
CCR-U5-03S
142
222
CCR-U5-04BR
576
129
CCR-U5-04D
504
433
CCR-U5-04S
360
183
CCR-U5-05D
387
451
CCR-U5-06DA
406
423
CCR-U5-06S
303
444
CCR-U5-08D
754
66
CCR-U5-08S
417
770
CCR-U5-09S
45
310
CCR-U5-10D
91
0
CCR-U5-10S
40
9
CLMW-01
295
537
CLMW-02
463
542
CLMW-03D
551
508
CLMW-03S
494
262
CLMW-04
152
135
CLMW-05S
66
210
Page 39

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
CLMW-06
35
124
CLP-01
58
423
CLP-02
70
157
GWA-01BRU
119
4
GWA-02BR
223
141
GWA-02BRA
203
120
GWA-02BRU
275
175
GWA-02S
152
203
GWA-03D
336
367
GWA-04D
425
244
GWA-04S
346
405
GWA-05BRU
420
72
GWA-05S
827
138
GWA-06D
35
0
GWA-06S
90
0
GWA-10D
119
25
GWA-10S
193
213
GWA-11BR
310
1
GWA-11BRU
293
37
GWA-11S
288
420
GWA-12BRU
103
0
GWA-12S
88
1
GWA-13BR
322
0
GWA-14BR
155
0
GWA-14D
349
0
GWA-14S
217
1
GWA-20BR
283
421
GWA-20D
403
105
GWA-20S
363
11
GWA-21BR
276
171
GWA-21 BRL
260
50
GWA-21 BRU
218
227
GWA-21S
269
145
GWA-22BRU
157
83
GWA-22S
83
74
GWA-23D
30
5
GWA-24BR
45
0
Page 40

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
GWA-24D
39
0
GWA-24S
1
0
GWA-25D
74
0
GWA-25S
43
6
GWA-26D
188
0
GWA-26S
1
2
GWA-27BR
208
257
GWA-27DA
293
204
GWA-28BR
118
117
GWA-28BRU
94
71
GWA-28S
38
5
GWA-29BRA
145
1
GWA-29D
63
1
GWA-30BR
90
0
GWA-30BRU
350
0
GWA-30S
64
0
GWA-31BRA
269
234
GWA-31D
667
302
GWA-32BR
170
0
GWA-32D
1
0
GWA-33BR
313
0
GWA-33D
271
0
GWA-33S
156
0
GWA-34BR
158
43
GWA-34S
116
28
GWA-35D
146
199
GWA-35S
131
110
GWA-36D
547
363
GWA-36S
167
170
GWA-37D
534
224
GWA-37S
174
220
GWA-38D
172
0
GWA-38S
291
0
GWA-42S
81
39
GWA-43D
266
0
GWA-43S
99
0
GWA-44BR
618
0
Page 41

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
GWA-44D
607
0
GWA-44S
756
0
GWA-45D
201
0
GWA-45S
81
0
GWA-47D
65
4
GWA-48BR
97
0
GWA-51D
458
204
GWA-54BRO
311
152
GWA-54D
303
159
GWA-54S
57
4
GWA-56D
308
0
GWA-56S
278
2
GWA-57BR
310
56
GWA-57BRU
534
13
GWA-57S
204
3
GWA-58BR
319
134
GWA-58BRU
519
140
GWA-58S
510
11
GWA-59BR
368
129
GWA-59D
339
62
GWA-60BR
362
0
GWA-60BRU
820
0
GWA-61 BR
573
0
GWA-61BRU
665
0
GWA-62BR
920
0
GWA-62BRU
385
0
GWA-63BRU
139
96
GWA-63S
32
179
GWA-64BRL
330
80
GWA-65BR
448
385
GWA-65BRL
1
2
GWA-66BRL
270
3
GWA-67BR
1
100
GWA-67BRL
240
6
GWA-68BRL
300
0
IB-01D
150
1
IB-01S
864
424
Page 42

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
IB-02AL
333
63
IB-02BRU
171
2
IB-02I
466
2
IB-02S-SL
596
600
IB-03D
244
4
IB-03S
360
516
IB-04BR
198
3
IB-04D
173
5
IB-04S-SL
527
600
IB-06D
244
3
IB-06S
520
25
IB-07D
264
22
IB-07S
317
383
MW-02DA
150
300
MW-04D
186
220
MW-08D
218
222
MW-08S
261
3
MW-10D
73
1
MW-10S
156
1
MW-11BRO
289
223
MW-11DA
253
141
MW-11S
220
79
MW-20D
179
116
MW-20DR
316
179
MW-21BR
109
0
MW-21D
47
0
MW-22BR
59
0
MW-22DR
29
0
MW-23D
694
0
MW-23DR
157
0
MW-23S
179
0
MW-24D
47
0
MW-24DR
116
0
MW-25DR
59
0
MW-30D
110
0
MW-30DA
98
0
MW-30S
27
0
Page 43

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-5C
OBSERVED AND SIMULATED TDS CONCENTRATIONS (mg/L) IN
MONITORING WELLS
Well
Observed TDS
(mg/L)
Computed TDS
(mg/L)
MW-32BR
97
0
MW-32D
64
0
MW-32S jj
50
0
MW-34BRU
113
50
MW-34S
1
9
MW-36BRU
122
51
MW-36S
41
13
MW-38BR
456
274
MW-38D
433
213
MW-38S
316
115
M W-40BRU
332
9
M W-40S
242
7
M W-42DA
324
0
MW-42S
123
0
U5-01D
84
49
U5-01S
222
197
U5-02BR
182
114
U5-02D
381
253
U5-02S-SLA
480
500
U5-02S-SLB
463
500
U5-03D
88
263
U5-04BRA
108
9
U5-04D
189
42
U5-04S
109
201
U5-05BR
1140
304
U5-05D
292
499
U5-06D
335
400
U5-06S
301
500
U5-07D
413
68
U5-07S
193
500
U5-07SL
1
409
U5-08BR
171
0
U5-08D
67
18
U5-08S
205
500
Notes•
Data collected through April 2019.
Prepared by: RLK Checked by: RAG
Page 44

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
AB-01BROR
385
123
793
123
AB-01D
1160
660
886
660
AB-01S
0
343
638
343
AB-02BRO
503
65
1629
65
AB-02D
334
138
1652
138
AB-02S
300
2500
2500
2500
AB-03BR
46
0
37
0
AB-03BRA
34
0
75
0
AB-03BRUA
66
0
88
0
AB-03I
47
1
1077
1
AB-03MA15
1660
1561
2276
1561
AB-03S
2660
2280
2280
2280
AB-03SL
1170
1561
2276
1561
AB-04BR
55
0
180
0
AB-04D
35
10
1477
10
AB-04LA15
488
1708
2275
1708
AB-04S
2600
2280
2280
2280
AB-04SL
1980
1708
2275
1708
AB-04UA15
2970
2280
2280
2280
AB-05BR
0
0
57
0
AB-05BRU
0
0
59
0
AB-05S
5650
5650
5650
5650
AB-06BR
0
14
1552
14
AB-06D
0
0
560
0
AB-06S
7440
7440
7440
7440
AB-07BR
93
0
277
0
AB-07BRU
90
0
225
0
AB-07S
1630
11629
12810
1629
Page 45

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
AB-08BR
341
41
1136
41
AB-08BRU
459
423
2328
423
AB-08I
807
480
3587
480
AB-08S
4330
4500
4500
4500
AB-09BR
0
0
4
0
AB-09D
73
0
11
0
AB-09S
6220
6220
6220
6220
AS-01D
679
0
2797
0
AS-01SB
1620
15
3038
15
AS-02BR
480
0
1254
0
AS-02D
340
1
1802
1
AS-02S
556
174
547
174
AS-03BRU
0
0
4
0
AS-04D
0
0
0
0
AS-04S
0
0
0
0
AS-05BR
0
0
6
0
AS-05BRU
0
0
9
0
AS-05S
0
0
1
0
AS-06BRA
0
0
2
0
AS-06D
0
0
0
0
AS-06S
0
0
1
0
AS-07BRB
79
0
1595
0
AS-07D
836
0
2499
0
AS-07I
607
10
2120
10
AS-07S
1480
1480
1480
1480
AS-08BR
34
0
1794
0
AS-08D
776
3
2225
3
AS-08S
117
1026
1138
1026
Page 46

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
AS-09BR
0
1
822
1
AS-09D
171
23
1364
23
BG-01 BRA
0
0
0
0
BG-01 D
0
0
0
0
BG-01S
0
0
0
0
BG-02D
25
0
0
0
CCPMW-01D
0
0
0
0
CCPMW-01S
0
0
0
0
CCR-03BR
6
22
348
22
CCR-04D
50
22
123
22
CCR-05D
77
1
25
1
CCR-06D
1430
15
1044
15
CCR-06S
1460
2033
4116
2033
CCR-07D
628
3
2341
3
CCR-07S
2960
674
3792
674
CCR-08BR
955
2
2293
2
CCR-08D
1550
79
2452
79
CCR-09D
903
117
1247
117
CCR-11D
1160
91
1535
91
CCR-11S
869
340
831
340
CCR-12BR
26
1
808
1
CCR-12D
301
6
1083
6
CCR-12S
1110
119
1083
119
CCR-13D
0
0
3
0
CCR-14D
1100
262
2629
262
CCR-15D
107
50
462
50
CCR-16D
41
0
1
0
CCR-16S
3080
11008
11797
1008
Page 47

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
CCR-17BR
0
0
256
0
CCR-IB-01D
30
1
6
1
CCR-IB-01S
157
250
275
250
CCR-IB-03BR
0
0
2
0
CCR-IB-03D
67
9
27
9
CCR-IB-03S
336
118
148
118
CCR-U5-01D
6
58
174
58
CCR-U5-02D
83
17
42
17
CCR-U5-03D
132
111
151
111
CCR-U5-03S
32
107
133
107
CCR-U 5-04BR
488
40
123
40
CCR-U5-04D
784
838
853
838
CCR-U 5-04S
602
803
648
803
CCR-U5-05D
426
230
284
230
CCR-U 5-06DA
182
179
245
179
CCR-U5-06S
176
194
261
194
CCR-U5-08D
195
2
42
2
CCR-U5-08S
17
285
298
285
CCR-U5-09S
400
272
309
272
CCR-U5-10D
9
0
0
0
CCR-U5-10S
5
9
5
9
CLMW-01
1360
202
3296
202
CLMW-02
589
42
1621
42
CLMW-03D
923
6
1999
6
CLMW-03S
903
70
1347
70
CLMW-04
58
206
336
206
CLMW-05S
0
402
801
402
CLMW-06
0
111
112
11
Page 48

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
CLP-01
204
194
902
194
CLP-02
47
244
470
244
GWA-01 BRU
0
0
3
0
GWA-02BR
100
24
85
24
GWA-02BRA
83
15
73
15
GWA-02BRU
132
7
105
7
GWA-02S
112
79
122
79
GWA-03D
397
65
237
65
GWA-04D
167
0
148
0
GWA-04S
168
101
235
101
GWA-05BRU
32
0
57
0
GWA-05S
0
42
113
42
GWA-06D
0
0
0
0
GWA-06S
0
0
0
0
GWA-10D
0
8
17
8
GWA-10S
81
131
142
131
GWA-11BR
216
0
3
0
GWA-11 BRL
29
0
0
0
GWA-11 BRU
285
25
48
25
GWA-11S
416
521
538
521
GWA-12BRU
0
0
0
0
GWA-12S
0
0
1
0
GWA-13BR
79
0
0
0
GWA-14BR
0
0
0
0
GWA-14D
96
0
0
0
GWA-14S
63
0
1
0
GWA-20BR
359
66
1863
66
GWA-20D
1010
1867
11795
867
Page 49

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
GWA-20S
379
859
1194
859
GWA-21BR
114
37
405
37
GWA-21BRL
230
0
219
0
GWA-21 BRU
158
387
546
387
GWA-21S
96
225
340
225
GWA-22BRU
0
2
460
2
GWA-22S
250
9
408
9
GWA-23D
0
1
8
1
GWA-24BR
0
0
0
0
GWA-24D
0
0
0
0
GWA-24S
45
0
0
0
GWA-25D
0
0
0
0
GWA-25S
0
0
1
0
GWA-26D
0
0
0
0
GWA-26S
0
1
12
1
GWA-27BR
224
7
2570
7
GWA-27DA
992
51
1894
51
GWA-28BR
0
29
237
29
GWA-28BRU
0
2
146
2
GWA-28S
0
0
9
0
GWA-29BRA
0
0
7
0
GWA-29D
0
0
2
0
GWA-30BR
0
0
0
0
GWA-30BRU
28
0
0
0
GWA-30S
0
0
0
0
GWA-31BRA
28
7
136
7
GWA-31D
35
90
150
90
GWA-32BR
0
10
10
0
Page 50

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
GWA-32D
0
0
0
0
GWA-33BR
199
0
0
0
GWA-33D
0
0
0
0
GWA-33S
25
0
0
0
GWA-34BR
0
0
25
0
GWA-34S
0
0
17
0
GWA-35D
107
0
122
0
GWA-35S
101
13
66
13
GWA-36D
177
0
216
0
GWA-36S
88
4
98
4
GWA-37D
64
0
135
0
GWA-37S
72
2
132
2
GWA-38D
0
0
0
0
GWA-38S
120
0
0
0
GWA-39S
1620
421
933
421
GWA-42S
29
21
330
21
GWA-43D
36
0
0
0
GWA-43S
67
0
0
0
GWA-44BR
46
0
0
0
GWA-44D
39
0
0
0
GWA-44S
32
0
0
0
GWA-45D
0
0
0
0
GWA-45S
0
0
0
0
GWA-47D
390
0
24
0
GWA-48BR
0
0
0
0
GWA-51D
750
6
882
6
GWA-54BRO
91
0
831
0
GWA-54D
86
10
1720
0
Page 51

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
GWA-54S
91
0
16
0
GWA-56D
0
0
1
0
GWA-56S
39
0
1
0
GWA-57BR
228
0
292
0
GWA-57BRU
59
0
69
0
GWA-57S
0
0
18
0
GWA-58BR
339
0
723
0
GWA-58BRU
0
0
718
0
GWA-58S
0
1
87
1
GWA-59BR
579
0
609
0
GWA-59D
503
0
279
0
GWA-60BR
0
0
0
0
GWA-60BRU
0
0
0
0
GWA-61BR
39
0
0
0
GWA-61BRU
0
0
0
0
GWA-62BR
361
0
0
0
GWA-62BRU
74
0
0
0
GWA-63BRU
98
0
242
0
GWA-63S
0
13
425
13
GWA-64BRL
239
0
213
0
GWA-65BR
415
5
1917
5
GWA-65BRL
83
0
51
0
GWA-66BRL
395
0
44
0
GWA-67BR
18
6
62
6
GWA-67BRL
158
0
8
0
GWA-68BRL
81
0
0
0
IB-01D
0
0
1
0
IB-01S
165
1273
1283
273
Page 52

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
IB-02AL
490
10
42
10
IB-02BRU
0
0
1
0
IB-02I
99
0
1
0
IB-02S-SL
240
400
400
400
IB-03D
357
0
6
0
IB-03S
880
760
760
760
IB-04BR
57
0
56
0
IB-04D
44
0
35
0
IB-04S-SL
390
650
650
650
IB-06D
116
1
12
1
IB-06S
838
25
44
25
IB-07D
0
5
15
5
IB-07S
212
219
257
219
MW-02DA
0
0
1333
0
MW-04D
81
364
531
364
MW-08D
138
596
1958
596
MW-08S
151
528
788
528
MW-10D
142
0
4
0
MW-10S
256
0
2
0
MW-11BRL
51
0
703
0
M W-11 BRO
97
20
1254
20
M W-11 DA
84
82
739
82
MW-11S
813
291
390
291
M W-20D
205
147
442
147
MW-20DR
174
17
843
17
MW-21BR
0
0
0
0
MW-21D
0
0
1
0
MW-22BR
0
10
10
0
Page 53

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
MW-22DR
0
0
0
0
MW-23D
51
0
0
0
MW-23DR
0
0
0
0
MW-23S
26
0
0
0
MW-24D
0
0
0
0
MW-24DR
0
0
0
0
MW-25DR
0
0
0
0
MW-30D
0
0
0
0
MW-30DA
0
0
0
0
MW-30S
0
0
0
0
MW-32BR
0
0
0
0
MW-32D
0
0
0
0
MW-32S
0
0
0
0
MW-34BRU
0
0
30
0
MW-34S
0
0
5
0
MW-36BRU
0
0
55
0
MW-36S
42
0
8
0
MW-38BR
45
0
179
0
MW-38D
226
0
141
0
MW-38S
163
0
72
0
MW-40BRU
0
0
7
0
MW-40S
29
0
4
0
MW-42DA
0
0
0
0
M W-42S
0
0
0
0
U5-01D
0
29
30
29
U5-01S
0
112
118
112
U5-02BR
88
56
68
56
U5-02D
130
148
152
148
Page 54

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 5-7
TRANSPORT MODEL SENSITIVITY TO THE BORON Kd VALUES
Well
Observed
Boron
(Ng/L)
Boron Model
(pg/L)
Model, Low Kd
Model, high
Ka
NRMSE
5.150/0
8.30%
5.25%
U5-02S-SLA
288
300
300
300
U5-02S-SLB
278
300
300
300
U5-03D
124
69
158
69
U5-04BRA
0
0
6
0
U5-04D
0
1
25
1
U5-04S
275
67
125
67
U5-05BR
538
147
234
147
U5-05D
216
492
495
492
U5-06D
180
209
238
209
U5-06S
158
289
300
289
U5-07D
141
0
40
0
US-07S
179
300
300
300
U5-07SL
180
245
245
245
U5-08BR
27
0
0
0
U5-08D
39
0
11
0
U5-08S
29
300
300
300
Prepared by: RLK Checked by: RAG
Notes•
Boron concentrations are shown for the calibrated model, and for models where the Kd is increased by a factor of
5 and decreased by a factor of 1/5.
Kd- soil -water distribution coefficients
Page 55

Updated Groundwater Flow And Transport Modeling Report December 2019
Cliffside Steam Station, Mooresboro, North Carolina
TABLE 6-1
ACTIVE GROUNDWATER REMEDIATION WELL SUMMARY
Number of Extraction
Total Depth
Wells
Formation
(ft bgs)
3
Saprolite
27-30
20
Saprolite /TRZ/Bedrock
49-133
Number of Injection
Formation
Total Depth
Wells
(ft bgs)
32
Saprolite
14-82
14
Saprolite /TRZ/Bedrock
54-122
Number of
Total
Length of
Approximate
Approximate
Total
Simulated
Horizontal
Screen
GS Elevation at
Spud Depth6
Injection Wells
Spud Depth
(ft BGS)
(gpm)
1
240
10
10
45
Prepared by: RLK Checked by: RAG
Notes:
One 250-foot horizontal infiltration well has an average flow rate of 45 gpm. The 23 extraction wells have an
average flow rate of 5.3 gpm and are pumped so that the water levels are near the bottom of the wells.
The 46 infiltration wells have an average flow rate of 3 gpm and the heads of the infiltration wells are maintained
ten feet above the ground surface.
Page 56

161P
synTerra TECHNICAL MEMORANDUM
Date: December 27, 2019
To: Scott Davies/Ryan Czop (Duke Energy)
From: Regina Graziano (SynTerra), Scott Spinner (SynTerra), and Jim Linton (Geosyntec)
Subject: Model Evaluation of TreeWellsTM , Units 1-4 ash basin, Cliffside Steam Station
Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Rogers Energy Complex,
location of the former Cliffside Steam Station (CSS, Station, Site) in Mooresboro, Rutherford and
Cleveland counties, North Carolina. The former Units 1-4 ash basin (U1-4 AB) at CSS has been
excavated. The northeast side of the U1-4 AB is bordered by the Broad River. The proposed
remediation area is a strip of land between the U1-4 AB and the Broad River. Samples of
groundwater downgradient of the waste boundary and near the compliance boundary indicate
concentrations of constituents of interest (COIs) greater than applicable criteria [North Carolina
Administrative Code (NCAC), Title 15A, Subchapter 02L, Groundwater Classification and
Standards (02L), Interim Maximum Allowable Concentrations (IMACs), or background
threshold values (BTVs), whichever is greater]. There are currently not any constituent
concentrations greater than NCAC, Title 15A, Subchapter 02B, Surface Water and Wetland
Standards (02B) in the Broad River, and the future conditions evaluation does not predict any
instances of COI concentrations being greater than 02B standards. Considering that the COI
source has been excavated, and the relatively low concentrations of COIs in groundwater, a
passive TreeWellTM system is proposed to treat groundwater in the remediation area.
REMEDIATION SYSTEM DESCRIPTION
A TreeWellTM system is a remedial alternative under evaluation to provide removal of COIs in
groundwater prior to discharge into the Broad River. The evaluation assumes 2.56 acres of
TreeWellsTM (285 units) downgradient of the former U1-4 AB. The units would be planted at
various depths in a staggered alignment for maximum areal coverage.
TreeWellTM systems commonly create localized hydraulic control based on the combined
pumping rates of the trees that compose the system. For TreeWellTM systems located near
surface water features, hydraulic effects, while present, may require additional analysis to
understand.
Modeling of the hydraulic influence of a TreeWellTM system adjacent to a surface water body
often times is masked by conditions created by the surface water body and the influence it
creates; therefore, the influence a TreeWellTM system has on the groundwater gradient may not
be as easily predicted or measured when adjacent to a surface water body.

Model Evaluation of TreeWellsTM
Former Units 1-4 Ash Basin, Cliffside Steam Station
December 27, 2019
Page 2 of 2
The remediation strategy of reducing COI discharge to the Broad River is based on the
following:
• The source has been removed and natural attenuation mechanisms are occurring.
• The groundwater will have a travel time of approximately 5 years to reach the
phytoremediation system from the farthest western portions of the former basin. Based
upon the retardation factor of the various COIs, the actual COI migration rate in
groundwater will be slower.
• It is predicted that the TreeWellsTM will intercept and evapotranspire an average of
about 3.1 million gallons of groundwater per year downgradient of the U1-4 AB. This
estimate is based on a yearly average water removal rate of 30 gallons per day per tree.
• The Broad River does not currently have, and is not predicted to have, COI
concentrations associated with the U1-4 AB that are greater than 02B standards.
MODELING
The numerical model was recently updated using flow and transport models MODFLOW and
MT3DMS for boron, sulfate, and total dissolved solids (TDS). Between the waste boundary and
the compliance boundary arsenic, boron, cobalt, iron, lithium, manganese, strontium, sulfate,
TDS, and total radium have been detected in groundwater at concentrations greater than their
applicable comparison criteria; however, not all COIs have a discernible plume and currently
are not outside the compliance boundary. Boron is typically the COI selected to estimate the
time to achieve compliance because it is mobile in groundwater and tends to have the largest
extent of migration; however the boron simulation predicts concentrations less than the 02L
standard by 2021. Sulfate and TDS were also modeled because they are conservative COIs
migrating from the basin footprint; however simulations also predict that sulfate and TDS
concentrations will be less than 02L standards by 2021. The less mobile, more geochemically
controlled constituents (i.e., arsenic, cobalt, iron, manganese, and strontium) will follow the
same flow path as that of boron, but to a lesser extent.
The phytoremediation conceptual design by Geosyntec (2019) (Figure 1), was applied to a
numerical simulation under current conditions. The area available for installation, northeast of
the U1-4 AB, is approximately 2.56 acres and can accommodate approximately 285 TreeWellTM
units. The entire TreeWellTM system would extract approximately 3.1 million gallons of
groundwater per year upon maturity. The phytoremediation design was simulated by
removing 3.1 million gallons of water per year from the treatment area. In the model, this water
was removed from model layers representing the saprolite and the transition zone at a depth of
30-40 feet below ground surface. The computed heads with the TreeWellsTM is shown in
Figure 2.
Maximum mass removal from tree wells was also calculated for the conservative COIs that are
mobilized geochemically. The COI concentration geomean was calculated from monitoring

Model Evaluation of TreeWellsTM
Former Units 1-4 Ash Basin, Cliffside Steam Station
December 27, 2019
Page 3 of 2
wells within the U14 AB and between the waste boundary and the compliance boundary. The
COI geomean was then multiplied by the TreeWellsTM removal rate of 3.1 million gallons of
water per year to determine the maximum mass removal rate (Table 1). The maximum mass
removal rate for COIs ranges from 0.01 lbs/yr to 121bs/yr.
The TreeWellsTM reduce groundwater flow towards the River in this area by several million
gallons per year. This removal of groundwater, coupled with the source removal that has
already occurred, is expected to achieve compliance with regulatory standards in the treatment
area.
ATTACHMENTS:
Table 1 Maximum Mass Removal from TreeWellsTM
Figure 1 System Layout Map
Figure 2 Hydraulic Head Contours
REFERENCE:
Geosyntec Consultants. 2019. Evaluation of Potential Application of Engineered Phytoremediation
and Conceptual Design-Cliftside Units 1-4. Technical Memorandum (Privileged &
Confidential -for Recipients Use Only). November 4, 2019.

Model Evaluation of TreeWellSTM
Former Units 1-4 Ash Basin, Cliffside Steam Station
ATTACHMENTS
December 2019

TABLE 1
MAXIMUM MASS REMOVAL FROM TREE WELLSTM
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
COIs
Arsenic
Chromium
Cobalt
Iron
Lithium
Manganese
Strontium
Total Radium
Reporting Units
pg/L
pg/L
pg/L
pg/L
pg/L
pg/L
pg/L
pCi/L
Geomean Concentration
0.57
0.90
1.15
480.45
4.52
288.69
201.28
1.69
Conversion to Ibs/gal
4.75E-09
7.51E-09
9.64E-09
4.01E-06
3.77E-08
2.41E-06
1.68E-06
-
Units
Ibs/yr
Ibs/yr
Ibs/yr
Ibs/yr
Ibs/yr
Ibs/yr
Ibs/yr
pCi/yr
Total Avg. Mass Removed
(Geomean x 3.1 million gal
per year)
1.47E-02
2.33E-02
2.99E-02
1.24E+01
1.17E-01
7.47E+00
5.21E+00
1.99E+07
Prepared by: WTP Checked by: RAG
Notes:
Wells within the former Unit 1-4 Ash Basin and between the waste boundary and the compliance boundary were chosen for the COI geomean.
' - Statistical mean, geomean, or median calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria.
Mean or geomean results were used based on the central tendency of the data set.
pCi/L - picocuries per liter
pg/L - micrograms per liter

I,
a "4
1
SPILLWAY
�+� mil--
It
t
1 f r. �
`Ajaw
milk
L
'T
(' DUKE
125 GRAPHIC SCALE
125 250
LEGEND
ENERGY
(IN FEET)
TREE WELLS
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
ASH BASIN WASTE BOUNDARY
REVISED BY: R. KIEKHAEFER DATE: 12/12/2019
CHECKED BY: T. GRANT DATE: 12/12/2019
ASH BASIN COMPLIANCE BOUNDARY
APPROVED BY: T. GRANT DATE: 12/12/2019
PROJECT MANAGER: S. SPINNER
synTerra
www.synterracorp.com
NOTES:
FIGURE 1
ALL BOUNDARIES ARE APPROXIMATE.
SYSTEM LAYOUT MAP
THE MODEL SIMULATED 2.56 ACRES OF TREEWELL'"' SYSTEM WITH A SIMULATED FLOW
MODEL EVALUATION OF TREEWELLST°°, UNITS 1-4 ASH
RATE APPROXIMATELY 3.1 MILLION GALLONS OF GROUNDWATER PER YEAR.
BASIN
AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON SEPTEMBER 7, 2018.
IMAGE COLLECTED ON APRIL 20,2018.
CLIFFSIDE STEAM STATION
HAS BEEN SET
MOORESBORO, NORTH CAROLINA
COORDINATEDRAWING
SYSTEMFPSI3 00( AD 3)TIONOFNORTHCAROLINASTATEPLANE

I' SOS
77
'70
'0p
69�
♦- � *1 680
♦ ♦ ssS
G6S , ♦
6'
r
LEGEND
TREE WELLS
HYDRAULIC HEAD (FEET)
ASH BASIN WASTE BOUNDARY
- - - ASH BASIN COMPLIANCE BOUNDARY
GRAPHIC SCALE
DUKE 125 0 125 250
ENERGY.
CAROLINAS ON FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
,4� REVISED BY: R. KIEKHAEFER DATE: 12/12/2019
CHECKED BY: T. GRANT DATE: 12/12/2019
APPROVED BY: T. GRANT DATE: 12/12/2019
PROJECT MANAGER: S. SPINNER
NOTES: FIGURE 2
ALL BOUNDARIES ARE APPROXIMATE. HYDRAULIC HEAD CONTOURS
THE MODEL SIMULATED 2.56 ACRES OF TREEWELL'"' SYSTEM WITH A SIMULATED FLOW MODEL EVALUATION OF TREEWELLSTM , UNITS 1-4 ASH
RATE APPROXIMATELY 3.1 MILLION GALLONS OF GROUNDWATER PER YEAR.
FOR MORE INFORMATION SEE SECTION ON HYDRAULIC CONTROL. BASIN
AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON SEPTEMBER 7, 2018. CLIFFSIDE STEAM STATION
IMAGE COLLECTED ON APRIL 20,2018. MOORESBORO, NORTH CAROLINA
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).

161P
synTerra TECHNICAL MEMORANDUM
Date: December 27, 2019
To: Scott Davies/Ryan Czop (Duke Energy)
From: Regina Graziano (SynTerra), Scott Spinner (SynTerra), and Tim Grant (SynTerra)
Subject: Model Evaluation of Extraction Wells and Trench, Unit 5 AB - Cliffside Steam
Station
Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Rogers Energy Complex,
formerly Cliffside Steam Station (CSS, Station, Site) in Mooresboro, Rutherford and Cleveland
counties, North Carolina (Figure 1). An evaluation of remediation options is underway for the
groundwater downgradient of the Unit 5 inactive ash basin (U5 AB) saddle dam due to
constituents of interest (COIs) concentrations being greater than regulatory values at and
beyond the compliance boundary. Low pH in the groundwater has caused geochemically
controlled constituents (cobalt, iron, manganese, and strontium) to mobilize in groundwater.
This model evaluation is for a remediation system designed to capture the mobile constituents
in groundwater in the area.
ACIDIC GROUNDWATER AND COI TRANSPORT
A localized area of low pH in groundwater occurs near the U5 AB saddle dam. Historical aerial
photographs show the sluice line discharged into the basin in this area. Operational
information from other facilities indicates it is likely that poor coal byproducts (also referred to
as 'coal rejects' or 'clinkers') might have been deposited near the sluice outfall with the ash.
Clinkers tend to be pyrite -rich and can cause low pH conditions in the subsurface.
The low pH groundwater currently emerges along the west side of Unit 5 cooling tower B,
where it is exposed to the surface environment. The groundwater partially discharges to the
ditch located adjacent to the cooling tower, and partially continues to flow as groundwater
north toward the U5 AB compliance boundary. The ditch becomes a "losing" water feature as
water moves north toward the intake to the wastewater treatment system. The water is moving
slowly in the ditch and there is ample residence time for infiltration of low pH water back into
the groundwater system. The COIs in the water flowing in the ditch is the suspected reason for
the concentrations to be greater than regulatory standards in groundwater at and beyond the
compliance boundary. Therefore, elimination of this transport mechanism is included in the
remedial approach.

Model Evaluation of Extraction Wells and Trench December 2019
Unit 5 inactive Ash Basin, Cliffside Steam Station Page 2 of 3
REMEDIATION SYSTEM DESCRIPTION
The remediation system evaluated includes a 380-foot long groundwater extraction trench and
12 extraction wells northeast of the U5 AB (Figure 1). The 380-foot trench is intended to collect
the low pH groundwater near the toe of the saddle dam. The extraction trench is assumed to be
approximately 20 feet deep and would be installed in the stormwater drainage feature along the
west and south of the Unit 5 cooling tower B. Groundwater extraction from the trench would
maintain a water level 15 feet below ground surface. The 12 extraction wells target the COIs
that have migrated near or beyond the compliance boundary. The 12 extraction wells are
assumed to be approximately 100 feet deep and screened in saprolite and the transition zone.
Operation of five extraction wells north of Unit 5 cooling tower A, five extraction wells south of
Unit 5 cooling tower A, and two extraction wells northwest of Unit 5 cooling tower B are
evaluated.
MODELING SIMULATIONS
The numerical model was recently updated using flow and transport models MODFLOW and
MT3DMS for boron, sulfate, and TDS. One well, GWA-36D, has detections of sulfate and TDS
greater than the 02L standards, however monitoring wells between the U5 AB saddle dam and
GWA-36D are lower than the detection limit and cannot be modeled because there is not a
discernable plume. Along the U5 AB saddle dam, cobalt, iron, lithium, manganese, and
strontium have been detected in groundwater at concentrations greater than applicable criteria
(02L standards, IMACs, or background values, whichever is greater); however, the less mobile
COIs (listed above) that have been mobilized geochemically by the suspected source material,
are causing low pH in groundwater which cannot be modeled in the MT3DMS model.
The extraction wells are simulated using a vertical series of MODFLOW DRAIN points. The
DRAIN bottom elevations are set to the center of the gridblock containing the drain. This
simulates a condition in which the water is being pumped out of the well casing to maintain a
water level near the bottom of the well. The DRAIN conductance is estimated by considering
radial flow to a well, following Anderson and Woessner (1992). For a horizontal hydraulic
conductivity of K, a well radius of rW, and horizontal and vertical grid spacing of Ox and Az, the
DRAIN conductance for a gridblock is computed as:
C=
27rKAz
In 0.208Ax (a)
rW
The conductance value is reduced by 50 percent to account for well skin effects.
The extraction trench is approximately 20 feet deep with a drain installed at the bottom. The
trench would maintain approximately 5 feet of water. The trench was simulated using the
DRAIN feature with a simulated head 15 feet below the ground surface. The simulation predicts
the extraction trench would remove approximately 5 gallons per minute (gpm) of groundwater.

Model Evaluation of Extraction Wells and Trench
December 2019
Unit 5 inactive Ash Basin, Cliffside Steam Station
Page 3 of 3
The 12 extraction wells are simulated to extract approximately 2 gpm per well, or
approximately 24 gpm total for the system. The computed heads and flow lines with the
remediation system operational are shown in Figure 2 and Figure 3. The remediation system
results in a cone of depression of the water table to an elevation below the Broad River, for
complete capture of the COIs in the area.
MODPATH particle tracking program, with forward tracking, was used to show the pathways
through which COIs could be hydraulically captured with the remediation system. Particle
tracking was simulated starting from the saddle dam area, the source area of the low pH in
groundwater (Figure 4). Particle tracking was simulated in the transition zone (layer 16)
because there were some dry cells in the saprolite and upper transition zone that cause errors in
the MODPATH calculation. The results of the particle tracking can be found in Figures 5 and
Figure 6. Figure 5 displays five years of particle tracking, and Figure 6 displays particle tracking
indefinitely. The simulation predicts that migration of COIs from the source area will be
captured by the extraction trench or wells within the compliance boundary.
The simulation results suggest that this would be an effective remediation design for this area.
ATTACHMENTS: Figures 1-6
REFERENCES:
Anderson, M.P., and W.W. Woessner, 1992, Applied Groundwater Modeling, Simulation of
Flow and Advective Transport, Academic Press, Inc, New York NY, 381p.

Model Evaluation of Extraction Wells and Trench
December 2019
Unit 5 inactive Ash Basin, Cliffside Steam Station
ATTACHMENTS

-
LEGEND
4' DU
E
GRAPHIC SCALE
125 0 125 250
N
EXTRACTION WELLS
CAROLINAS
(IN FEET)
UNIT 5 TRENCH DRAIN
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
ASH BASIN WASTE BOUNDARY
CHECKED BY: T. GRANT DATE: 12/13/2019
APPROVED BY: T. GRANT DATE: 12/13/2019
ASH BASIN COMPLIANCE BOUNDARY
synTerra
PROJECT MANAGER: S. SPINNER
www.synterracorp.com
NOTES:
FIGURE 1
ALL BOUNDARIES ARE APPROXIMATE.
�+
SYSTEM
STEM LAYOUT MAP
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
MODEL EVALUATION OF EXTRACTION WELLS AND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
TRENCH, UNIT 5 AB
FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
CLIFFSIDE STEAM STATION
CAERIAL OLLECTED ON MAY 8Y 0115AINED
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
MOORESBORO, NORTH CAROLINA
COORDINATE SYSTEM FIPS 3200 (NAD83).

00
0
66�
4.
LEGEND
rj EXTRACTION WELLS
UNIT 5 TRENCH DRAIN
HYDRAULIC HEAD (FEET)
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
665 �
4 0
690
i 14
�1
1
1
1
1
1
a `
1
1
1
•
1
1
/
1
1
1
GRAPHIC SCALE
DUKE 125 0 125 250
ENERGY.
CAROLINAS (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
CHECKED BY: T. GRANT DATE: 12/13/2019
APPROVED BY: T. GRANT DATE: 12/13/2019
T -_-- PROJECT MANAGER: S. SPINNER
FIGURE 2
HYDRAULIC HEAD CONTOURS
MODEL EVALUATION OF EXTRACTION WELLS AND
TRENCH, UNIT 5 AB
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

�O
6
660
66s
ME
670
675 665 �%
LEGEND
VELOCITY VECTORS
EXTRACTION WELLS
UNIT 5 TRENCH DRAIN
HYDRAULIC HEAD (FEET)
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
720
'25
730
735
1
'40
r
45
ir7501 1
1
GRAPHIC SCALE
DUKE 125 0 125 250
ENERGY.
CAROLINAS (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
CHECKED BY: T. GRANT DATE: 12/13/2019
APPROVED BY: T. GRANT DATE: 12/13/2019
synTerra PROJECT MANAGER: S. SPINNER
www.synterracorp.com
FIGURE 3
FLOW VELOCITY VECTORS
MODEL EVALUATION OF EXTRACTION WELLS AND
TRENCH, UNIT 5 AB
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

UNIT 5
INACTIVE
ASH BASIN
LEGEND
DUKE
GRAPHIC SCALE
125 0 125 250
EXTRACTION WELLS
4 ENERGY
CAROLINAS
ON FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
UNIT 5 TRENCH DRAIN
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
CLINKER AREA
��
CHECKED BY: T. GRANT DATE: 12/13/2019
ASH BASIN WASTE BOUNDARY
APPROVED BY: T. GRANT DATE: 12/13/2019
PROJECT MANAGER: S. SPINNER
ASH BASIN COMPLIANCE BOUNDARY
synTerra
www.synterracorp.com
NOTES:
FIGURE 4
ALL BOUNDARIES ARE APPROXIMATE.
POTENTIAL LOW PH SOURCE AREA
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
MODEL EVALUATION OF EXTRACTION WELLS AND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
TRENCH, UNIT 5 AB
FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
CLIFFSIDE STEAM STATION
CAERIAL OLLECTED ON MAY 8Y 0115AINED
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
MOORESBORO, NORTH CAROLINA
COORDINATE SYSTEM FIPS 3200 (NAD83).

EXTRACTION WELLS
PARTICLE PATH
UNIT 5 TRENCH DRAIN
CLINKER AREA
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
GRAPHIC SCALE
n ENERGY.
125 0 125 250
4DUKE
CAROLINAS (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
CHECKED BY: T. GRANT DATE: 12/13/2019
APPROVED BY: T. GRANT DATE: 12/13/2019
PROJECT MANAGER: S. SPINNER
FIGURE 5
PARTICLE TRACKING AFTER 5 YEARS
MODEL EVALUATION OF EXTRACTION WELLS AND
TRENCH, UNIT 5 AB
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA

UNIT 5
INACTIVE
ASH BASIN
LEGEND
EXTRACTION WELLS
PARTICLE PATH
UNIT 5 TRENCH DRAIN
CLINKER AREA
ASH BASIN WASTE BOUNDARY
ASH BASIN COMPLIANCE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE
THE 12 EXTRACTION WELLS HAVE AN AVERAGE FLOW RATE OF 2 GPM AND EXTEND
FROM SAPROLITE TO THE TRANSITION ZONE (MODEL LAYERS 9 TO 16). THE DRAIN HAS
ATOTAL FLOW RATE OF 5 GPM AND HAS A HEAD 15 FEET BELOW GROUND SURFACE.
AERIAL PHOTOGRAPHY OBTAINED FROM ESRI ON DECEMBER 4, 2019. AERIAL WAS
COLLECTED ON MAY 8, 2015.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
1
1
I 1
1
1
1
1
1
1
1
/
1
/
1
GRAPHIC SCALE
n ENERGY.
125 0 125 250
4DUKE
CAROLINAS (IN FEET)
DRAWN BY: R. GRAZIANO DATE: 12/05/2019
REVISED BY: R. KIEKHAEFER DATE: 12/13/2019
CHECKED BY: T. GRANT DATE: 12/13/2019
APPROVED BY: T. GRANT DATE: 12/13/2019
PROJECT MANAGER: S. SPINNER
FIGURE 6
PARTICLE TRACKING INDEFINITELY
MODEL EVALUATION OF EXTRACTION WELLS AND
TRENCH, UNIT 5 AB
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA