NCDEQ Presentation 01_14_2016_FINAL

1
D
NCDEQ Briefing on Groundwater
Investigations
1/14/2016

Meeting Objectives
Third Party Reviewers
Site Investigations
Plume Geometry
Flow Direction
Analysis of Offsite Wells
Site Background Concentrations
Duke's Response to Comments
Conclusions

Third -Party Review
The National Ash Management Advisory Board was assembled by UNC Charlotte at the
request of Duke Energy and consists of nationally and internationally recognized and
published experts. Duke Energy has engaged NAMAB to complete independent reviews
of the Comprehensive Site Assessments and the Corrective Action Plans.
John Daniels, D. Eng., P.E.
Professor and Chair, UNCC - Department of Civil and Environmental Engineering
Chairman, Ash Management Advisory Board
Susan E. Burns, Ph.D., P.E.
Georgia Power Distinguished professor, School of Civil and Environmental Engineering, Georgia
Tech
Panelist, Ash Management Advisory Board, Groundwater Subcommittee
Jeffrey C. Evans, Ph.D., P.E.
Professor of Civil and Environmental Engineering, Bucknell University
Panelist, Ash Management Advisory Board, Groundwater Subcommittee
Krishna Reddy, Ph.D., P.E.
Professor of Civil and Environmental Engineering, University of Illinois at Chicago
Panelist Ash Management Advisory Board, Groundwater Subcommittee
Joyce Tsuji, Ph.D., DABT, Fellow ATS
Principal Scientist, Exponent, Inc.
Panelist, Ash Management Advisory Board, Groundwater Subcommittee
3

Third -Party Review
Ronald Falta, Ph.D.
Professor, Clemson - Department of Environmental Engineering and Earth Sciences
Modeling
Lawrence Murdoch, Ph.D. , P.G.
Professor, Clemson - Department of Environmental Engineering and Earth Sciences
Modeling
Bill Langley, Ph.D.
Professor, UNC Charlotte - Geography and Earth Sciences
Modeling
Lisa A Bradley, Ph.D., DABT
Haley and Aldrich, Boston, MA - Vice President and Senior Toxicologist
Off-site drinking water wells; risk assessments
4

Third -Party Review
Chunmiao Zheng, Ph.D.
Professor, University of Alabama — Department of Geological Sciences
Model Reviewer
John Ewing, P.E.
Senior Water Resources Engineer, Intera, Inc.
Model Reviewer
James Rumbaugh
President at Environmental Simulations, Inc.
Model Reviewer
Bruce Hensel
EPRI (Electric Power Research Institute)
Directed and managed model review
William Linderfelt, Ph. D.
Principal Hydrogeologist, Intera, Inc.
Model Reviewer
5

Groundwater Investigation Highlights
Dr. John Daniels, D.Eng, P.E.

Risk Classification and Corrective Action
Risk Classification
(Method and Timing of
Pond Closure)
• Range of options
Low Plan by 2018
Risk• Closed by 2029
• Requires excavation
Intermediate • Plan by 2017
Risk • Closed by 2024
• Requires excavation
High• Plan by 2016
Risk• Closed by 2019
Corrective Action
(Groundwater Remediation)
• Applicable to all
closure options
• Supplements
closure option
• Adaptable to
changing site
conditions and
receipt of new data
• Must be approved
by NCDEQ

Excavation, fully lined and capped 4
Fully Lined Landfill
or Structural Fill row,
Rralnage IayP P-t-tiye soil layer
VOgetak,on
40-0 synthetic bit-er
Structural High Risk
Impoundment � & � Intermediate Risk
Environmental Low Risk
Excavate, cap, or other innovative and sustainable options
Fully Lined Landfill
or Structural Fill
Groundwal
Bedrock
Cap with other engineerine
Rain ,I

General hydrogeologic theory
Flow from high energy (ponds)
to low energy (surface water)
Follows topography
Historical pond monitoring
(2005-2015)
Steady State
Flow Direction
Plume generalities
(contaminant concentration range)
Comprehensive Site Assessments
Plume maps
ES1 Plan View
Cross Sections
General Principles
SYSTEM 4
-_
rt [!� "I"
Slope Aquifer Boundary and Topographic DiiAde
Discharge Boundary
- - - - - - - Compartment (C) Boundary
..............— -Water Table
r : Fractures
�► Groundwater Flow Direction
9

General Flow Direction and Plume Extent
Groundwater Flow:
General groundwater flow was as expected based on accepted
hydrogeologic theory and historical monitoring
Regional groundwater flow at each site is away from neighbors, except at
L.V. Sutton Energy Complex and Asheville Steam Electric Plant, and
towards regional water bodies in the area
Plume Extent:
The plume is generally confined to the property boundary, except at four
sites that are being addressed with accelerated remediation as required in
the Sutton Settlement
No evidence of impact to outside wells except at L.V. Sutton Energy
Complex and Asheville Steam Electric Plant.
10

Example Stations
Stations included in the previous meeting with NCDEQ and those with
pending rankings (low -intermediate) were chosen to help provide
additional information needed to finalize their priority status
Allen Steam Station
Belews Creek Steam Station
Buck Steam Station
Cliffside Steam Station
Marshall Steam Station
Roxboro Steam Electric Plant

Allen Steam Station
12
't �v
LEGEND
\
N
uNEP aRNATe waTEr+suPPLY WELL
FIELD
.* D IpENTIFIEP PRIVATE WPTER SUPPLY WELL
y?t PLIO— YATER SUPPLYWELL
�'� •�
),
4/ 1 1
RECOR DED PR NATE WATER SU PP LY WELL
55
RFPaRrEp PR wnrER SUPPLY WELL
j S
GRWNPWATER ASSESSMENT MONITORING WELL
ter`
Yi
� eoMPLIANeEcaewNDwar€R MaNRGR,ncw€u
.,� L
?
—UNTARY GROUNDWATER MMI—INGWELL
PROPOSE—D—AL MONITORINGWELL
GEOLOGIC CRGSB .RECTION
MF GRO—EROYJDNNI
ESAN..S
_
T •i �
� ASH BASIN COMPLIANCE eONNOARY
V
4MTH OORE ENERGY PROPERTVBOIINONIAFI—ARVI DENT
I -
ASH BASIN WASTE BONNOARV
Y�I
1IFs�I� I'J --:•.I
�L.! 1
���� —EENEp GVPROPERYY BAUNOARY
RTR"M
L+3,�1 lhf In�CJ, �3t12d� �M, a
f
j11
Af
�
r�1aiL;n^f
F?cJ1YJg13�
12

WEST
616111., Ego] Ikq1■ TH1�7
COMPLIANCE BOUNDARY CCINCIDENT
WITH PROPERTY BOUNDARY
INACTIVE
ASH BASIN
FILL
ASH STORAGE
AREA
Allen Steam Station
RAB ASN RETIRED ASH
LANDFILL BASIN DAM
i
- - - - - �- INACTIVE ASH
REGOLITH
BEDROCK
CROSS SECTION - ALLEN INACTIVE ASH BASIN
(LOOKING NORTH)
NOTE:
TRANSECT D -D` FROM THE CSA REPORT USED FOR CROSS-SECTION SHOWN ABOVE,
DRAWING NOT TO SCALE AND IS INTENDED FOR ILLUSTRATION PURPOSES ONLY.
APPROXIMATE EXTENT OF 2L
EXCEEDANCES OF BORON
LEGENa
0 ASH
- RECOLTTH
PARTIALLY WEATHERED ROCK (PWR)
O BEDROCK
FI LL
APPROXIMATE EXTENT OF 2L
EXCEEDANCES OF BORON
APPROXIMATE ORCUNDWATER
FLOW DIRECTION
13
}
a
0
z
D
w
Z
0
ED
J
w
0
9
Iz
EAST
w
D_
J
a
0
d
0
I
I
ATAWBA
RIVER
0 ASH
- RECOLTTH
PARTIALLY WEATHERED ROCK (PWR)
O BEDROCK
FI LL
APPROXIMATE EXTENT OF 2L
EXCEEDANCES OF BORON
APPROXIMATE ORCUNDWATER
FLOW DIRECTION
13

Modeled boron concentration (ug/L)
in the transition zone
LEGEND
50 (BackgiGund
�onc�r�1� d1i� f1'I
50 - 2DO
200-400
400-700( #arldiard)
700-15.00
1.5-21) - 2.,50
DUCE ENERGY
PROPERTY aOU14DARY
ASH BASIN WASTE
ROUN DARY
LANDFILLfASH STORAGE
AREABOUNDARY
A51-1 SA ISN i: -OM
8.O JAI D,ARY
ASH BASIN COFNIPLIANG�
aOUN DARYOCINC 11DENT
STH DUKE ENFRC-Y
PROPERTY EPOUNDARY
MODEL DOMAIN
I
Allen Steam Station
14

Summary
Allen Steam Station:
Topographic divide west of the ash basin generally along Highway
273
Lake Wylie is a regional groundwater discharge feature
Groundwater flow direction is generally from topographic high areas
to the east toward Lake Wylie
Groundwater at the site flows away from neighbors
Boron was detected above the 2L Standard in bedrock at only one
location, close to Lake Wylie and away from drinking water wells
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
15

x' LEGEND:
./
c 3tit�}°
r �•Yv
xi' ■ tip
ASH BASIN f f
' ■I
■
■
'!■%
■r. ■ BELEWS LAKE
ELEV, - 925'
-
�,- •. '0s d" jt %4.,. JAPPROXIMATE)
ypt
"'PINE HALF_ ROAD ji h
l �JW ■ YV n
N�1 ASH LANDFILL .�
ISO
S �BELEW SCREEK
STATION
r �
Air
■
'• �.
7�[ BELEWS LAKE �/ g"_-

Belews Creek Steam Station
w
Cir :JL
`14 `14
J p J p
a= aZ
A
CROSS SECTION - BELEWS CREEK ACTIVE ASH BASIN
(LOOKING WEST)
NOTE:
TRANSECT A -A' FROM THE CSA REPORT USED FOR CROSS-SECTION SHOWN ADOVE.
DRAWING NOT TO SCALE AND IS INTENDED FOR ILLUSTRATION PURPOSES ONLY.
A
LEGEND
0 ASH BASIN SURFACE WATER
0 ASH
- REGOLITH
PARTIALLY WEATHERED ROCK/TRANSITION
- ZONE (PWR/TZ)
0 HEDROCK
FILL
APPROXIMATE EXTENT OF 2L
0 EXCEEDANCES OF BORON ABVD/OR
TOTAL DISSOLVED SOLIDS
APPROXIMATE GROUNDWATER
FLOW DIRECTION
17

Belews Creek Steam Station
Modeled boron concentration (ug/L)
in the transition zone
LEGEND
Dry Cell
— 50 (Background
Concentration)
50 - 700 (Standard)
700-5,000
5,000 - 10,000
10,000 - 15,000
15,000 - 20,000
20,000 - 26,186
ASH BASIN
COMPLIANCE
BOUNDARY
ASH BASIN
COMPLIANCE
BOUNDARY
- COINCIDENT WITH
DUKE ENERGY
PROPERTY
BOUNDARY
ASH BASIN WASTE
BOUNDARY
DUKEENERGY
PROPERTY
BOUNDARY
STRUCTURAL FILL,
ASH LANDFILL -EDGE
OF WASTE
MODEL DOMAIN
2115 No Action
2015 Current
2115 Cap in Place
2115 Excavation "

Summary
Belews Creek Steam Station:
Water flows predominantly toward the north and northwest toward
the Dan River
There are no water supply wells between the source areas and the
Dan River
Boron was detected above the 2L Standard within the ash basin
compliance boundary in the shallow and deep flow layers
2L exceedances were reported north-west of the ash basin. There
are no receptor wells in this area and groundwater remediation will
be performed at this location.
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
19

Buck Steam Station
20

SOUTH
r
0
z
Cr C2
Q
or
z�
Q W
M d
Q
w �
C) n
Z =
CL
O z
U W
U
0
U
A
Buck Steam Station
LEGEND
NOTE
EAST CROSS SECTION - CELL 2 PRIMARY POND
(LOOKING WEST)
DRAWING NOT TO SCALE AND IS INTENDED FOR ILLUSTRATION PURPOSES ONLY_
YADKIN
RIVER
A'
ASH
REGOLITH
PARTIALLY WEATHERED ROCK (PWR/TZ)
BEDROCK
FILL
APPROXIMATE EXTENT OF 2L
EXCEECIANCES OF BORON
APPROXIMATE GROUNDWATER
FLOW DIRECTION
21

Modeled boron
concentration (ug/L) in
the transition zone
N
��� G 509 1.DOP
t• «. !��'-\ ,. -- regio
2115 No Action
Buck Steam Station
r4:
a
i auu
2015 Current
2115 Cap In Place
LEGEND
<= 50 (Background
Concentration)
50-75
75.17'9
179 - 700 (Standard)
700-1,500
1,500 •2,500
2.500-3182
DUKE ENERGY
PROPERTY BOUNDARY
ASH BASIN WASTE
BOUNDARY
ASH BASIN
COMPLIANCE
BOUNDARY
ASH BASIN
COMP"ANCE
_ BOUNDARY
COINCIDENT WITH
DUKEENERGY
PROPERTY BOUNDARY
Q (MODEL DOMAIN
22

Summary
Buck Steam Station:
Groundwater flow is predominately in the north direction toward the
Yadkin River and away from neighbors
There is a component of flow to the west of cell 1 and there is
localized flow in an area east between cells 2 and 3 that is under
further investigation
Boron was detected above the 2L Standard in bedrock at only one
location close to the Yadkin River
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
23

�n

SOUTH
Cliffside Steam Station
ASH STORAGE AREA
(WFSTFRN PORTION)
NORTH
EXCEEDANCES OF BORON AND SULFATF - -'
A
CROSS SECTION - CLIFFSIDE ASH STORAGE AREA.
(LOOKING WEST)
NOTE:
DRAWING NOT TO SCALE AND IS INTENDED FOR ILLUSTRATION PURPOSES ONLY.
A'
LEGEND
® ASH
- RESCLITH
PARTIALLY WEATHERED ROCK (PWRJTZ)
0 BEDROCK
FILL
APPROXIMATE EY.TENT OF 2L
EXCEFDANCES OF BORON AND
SULFATE
APPROXIMATE GROUNDWATER
FLOW DIRECTION
25

Modeled boron concentration (ug/L)
in the transition zone
LEGEND
Dry Cell
<- 50 (Background
Cancentrajion}
50-250
250 - 700 (Standard)
700-1,000
9,000 - 2,500
2:500 - 5,000
5000-7722
MOO DOMA%N
ASH STORAGE
DUDE ENERGY PROPERI-V
.'
_
DOUNDARY
ASH BASIN WASTE
BOUNDARY
ASH BASIN COMPLIANCE
BOUNDARY
ASH BASIN COMPLIANCE
e _ BOUNDARY C10INCIDENT
WITH € UKE ENERGY
PROPERTY BOUNDARY
2115 No Action
Cliffside Steam Station
2015 Current
�.. r.�- •s , +�@•�,, � ;`x.. ',auk '� ,� ,-.'`' �
L A
b'' 0 550 1�QO
2115 Cap In Place 2115 Excavate 26

Summary
Cliffside Steam Station:
The Broad River and Suck Creek serve as groundwater discharge
features for the groundwater flowing from the site
Groundwater under the site flows toward the north and discharges to
the Broad River
Groundwater flow to the west of the active ash basin and east of Unit
6 is towards Suck Creek which discharges to the Broad River
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
27

Marshall Steam Station
28

Marshall Steam Station
APPROXIMATE EXTENT OF 2L APPROXIMATE EXTENT OF 2L
EXCEEDANCES OF BORCJN EXCEEDANCES OF BORON PWR/TZ
�y ASH BASIN
ASH A'ASI q
BEDROCK
CROSS SECTION - MARSHALL ASH BASIN
(LOOKING NORTHEAST) LEGEND
NOTE:
TRANSECT A -A' FROM THE CSA REPORT USED FOR CROSS-SECTION SHOWN ABOVE.
DRAWING NOT TO SCALE AND IS INTENDED FOR ILLUSTRATION PURPOSES ONLY.
ASH BASIN DAM
LAKE
NORMAN
® ASH
- REGOUTH
- PARTIALLY WEATHERED ROCK (PWR/TZ).
0 BEDROCK
- FILL
® APPROXIMATE EXTENT OF 2L
EXCEEDANCES OF BORON
APPROXIMATE GROUNDWATER
FLOW DIRECTION
29

Modeled boron
concentration (ug/L) in
the transition zone
Marshall Steam Station
2015 Current
LEGEND
<- 100 (Background
Concentration)
100 - 700 (Standardy
700-5,000
5,000 - 10,000
10,000 - 15,000
15,000 - 20,000
20,000 - 28,186
DUKE ENERGY PROPERTY
BOUNDARY
ASH BASIN WASTE
BOUNDARY
_ ASH BASIN COMPLIANCE
BOUNDARY
ASH BASIN COMPLIANCE
BOUNDARY COINCIDENT
HATH DUKE ENERGY
PROPERTY BOUNDARY
0.5 MILE OFFSET FROM
ASH BASIN COMPLIANCE
BOUNDARY
_ LANDFILLISTRUCTURAL
FILL BOUNDARY
MODEL DOMAIN
2115 No Action 2115 Cap In Place 2115 Excavate 30

Summary
Marshall Steam Station:
Groundwater flows beneath the ash basin to the southeast toward
Lake Norman and slightly east towards an unnamed tributary
Coal ash -related contaminants appear to be contained within the ash
basin compliance boundary
Groundwater at the site flows away from neighbors
Boron was detected above the 2L Standard in bedrock at only one
location beneath the closed Dry Ash Landfill
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
31

.E
`4 � r�; . "®� , � , Vii • :.�Q���C�
-low,
fl
f
w �
a
a

B
9RA
480
Oxo
aeo
450 -
�g499
G430
4x0
Flo
a3o
�A
Roxboro Steam Electric Plant
SECTION A—A' — BORON
—N—RIH—
® IL . als:^�wrrae
SECTION 6-B' - BORON
FALI.MG NEST
G PAPH'C SCALE
3W 0 3]C 6O0
HQRISOMAL 1'•300'
ED R � 6C1
vE-CG L 1'-3]
590
"M
LEGEND
_ COALASH
A'
O REGOLITH FILLMATERIAL-
ASH
_ TRANSITIONZONE
—SOCK
5Bb
WATER LEVEL
550
©
ASH BASIN WATER LEVEL
��—
530
�—
—N ITIPNZONEWATERLEVEL
IiOW510
510
soo
OSSERVED IN ROCK CORE
9BA
4BD
4]0
HASH MARKS FOINTTC
DECREASING CONCENTRATIONS
Isx3AcnvE
CONCENTRATIONCONTODR
DASHED MERE INFERRED
soe
CPNCENTHATION
-----------
___---_--=_-__--=BED
NCTANALYZED
NO
NO DATA
--------------
NOT SAMPLED
---------------
BEf?QC„N,
403
__
-----------------
]
.____----_
NSRWd[wln�H
9__________________________________________
o
35A
SECTION A—A' — BORON
—N—RIH—
® IL . als:^�wrrae
SECTION 6-B' - BORON
FALI.MG NEST
G PAPH'C SCALE
3W 0 3]C 6O0
HQRISOMAL 1'•300'
ED R � 6C1
vE-CG L 1'-3]
590
"M
BORING SYMBOLS
SOIL
sauaLF I -L —N—
"LONtEMIUTiCM
inti pe'4M Ar.
33
LEGEND
_ COALASH
GYPSUM
O REGOLITH FILLMATERIAL-
ASH
_ TRANSITIONZONE
—SOCK
_ FU MATERIAL
WATER LEVEL
ASHPOREWATERLEVEL
©
ASH BASIN WATER LEVEL
��—
BEDS PCK WATERLEVEL
�—
—N ITIPNZONEWATERLEVEL
nt
FRACT REDZ IDIZEC ZONE
OSSERVED IN ROCK CORE
CCNCENTRAMN CONTOUR
HASH MARKS FOINTTC
DECREASING CONCENTRATIONS
...
CONCENTRATIONCONTODR
DASHED MERE INFERRED
soe
CPNCENTHATION
NA
NCTANALYZED
NO
NO DATA
NS
NOT SAMPLED
BORING SYMBOLS
SOIL
sauaLF I -L —N—
"LONtEMIUTiCM
inti pe'4M Ar.
33

It
MOR.TH
69A
Ian
ON,
1QIi
MO
53n
57D
51D
wD jj
*5n
AM
iTn
41'
Z
Z
Ain
nD
1115
Roxboro Steam Electric Plant
-------------
SECTION C -C'
""TH
LEGEND
_ COAL ASH OYRSDNI
soft
REGOLITH FILLMATERML
'DQ
ASH
TRANSMONZONE
A 14I
eHnROCK
-14
FILL MATERIAL
"N
WATER LEVEL
ROBE WATER LEVEL
93Q
570
© ASH BASIN WATER LEVEL
41n
j— IL R=C VYATERLEVEL
TNANSITIONZCNEVVFTERLEVEL
F"CMREEIO%IDIP£DZONE
{�
1
06 ERVED IN ROCK CORE
00
OONGENT%k7ON CCNTODR
HASH MARKS P IINTTO
mr
din
DECREASING CONCENTRATIONS
.i. CONCENTRATION CONTOUR
a
DA&NEOVHFRFINFERRFO
ZaB
SAB CONCENTRATION
+iR
NA NOT ANALYZED
ND No DATA
Z7Q
NS NOTSAMPLEO
80RING SYMBOLS
snNwe
v�ELL> T
mrvcau:RAF�cw
_ fM1�nm�amr asr itlnl
flGnppa 4nry lnaHl
34

Modeled boron concentrations
(ug/L) in the transition zone
40004
700
Roxboro Steam Electric Plant
2015 Current
2045 No Action 2045 Cap -In -Place
— 7 a 1
2045 Excavate

Summary
Roxboro Steam Electric Plant:
Regional groundwater flow is to the west/northwest toward the Hyco
Reservoir
A discharge canal and topographic ridge located west of the Site ash
basins limits groundwater flow in that direction
Localized groundwater high zones are centered around the ash
basins, with radial flow in these areas
Boron was detected above the 2L Standard in bedrock at three
locations on site and away from drinking water wells
No evidence of impacts to offsite receptors
No imminent hazard to human health or the environment
36

Site Background Concentrations
Provisional proposed site background concentrations were included in the
CAP Part 1, alternative methods can be found in the table below
These values are based off of available data and will be updated as more
sampling is completed
Site Background versus Regional Background: How are they different?
Example of Alternative Site Background Concentrations: Weatherspoon
Parameter
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Chloride
Chromium
Background
Sample Size
3
3
3
3
3
3
3
3
1
Calculated
Calculated
Calculated
Calculated
Calculated
Calculated
Calculated
Background
Calculated
Method
Background
Background
Background
Background
Background
Background
Background
Concentration
Background
Concentration
Concentration
Concentration
Concentration
Concentration
Concentration
Concentration
(mg/L)
Concentration
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
(ug/L)
NC21- Standard
NA
1*
10
700
4*
700
2
250
10
Maximum
66
1
1
52
1
50
1
3.30
1
75% of Maximum
50
0.750
0.750
39
0.750
37.5
0.750
2.48
0.750
50% of Maximum
33
0.500
0.500
26
0.500
25
0.500
1.65
0.500
Mean
32
1
1
49.3
1
1 50
1
3.17
1
ACI -2
82.3
1
1
55.6
1
1 50
1
3.42
1
ACLS
71.7
1
1
56.8
1
1 50
1
3.45
1
Nondetects identified as ND, as opposed to the method detection limit, were omitted from calculations.
IQR (Interquartile Range) = 75th percentile - 25th percentile
ACI -2 (Alternative Concentration Limit 2): median + 1.65 x IQR
ACLS (Alternative Concentration Limit 3): median + 1.65 * IQR (where IQR = the interquartile range).
37

Mounding
Duke's Response to Comments
38

n
Recharge
Area w
(Flan View)
L
Vertical Percolation _
Mounding
Concern Defined
This concern refers to the extent to which ash
ponds raise or variably influence the natural
potentiometric surface, causing flow to leave
the basin radially, and against the prevailing
slope aquifer gradient.
Topographical and monitoring well data establish the extent to which localized mounded
hydraulic gradients emanating from a given ash basin effect groundwater direction. The net
effect of localized mounded gradients are captured by the current data set.
Historical operations of ash basins were managed within narrow tolerances. For example,
ash basin elevations have been controlled with hydraulic structures (e.g., stop logs) to within
1/2 of foot.
Ash basin mounding occurs locally within a larger slope aquifer system. As such, this
system still controls overall site gradient. It is contained within and defined by hydraulic
boundaries including topographical divides, drainage features (streams), and groundwater
discharge locations.
39

Mounding
Deep fractures
Duke's Response to Comments
40

Deep Fractures
Concern Defined
This concern refers to the extent to which
fractures and fissures serve as a conduit
between off site water wells and contaminated
groundwater.
Coal ash contaminants are dissolved in water with no measurable increase in density, as
compared to other contaminants which would tend to "sink" in the aquifer, such as dense
non aqueous phase liquids (DNAPL) or saltwater.
Monitoring well data indicate less contamination with depth.
Equipotential data indicate that lateral flow predominates over downward flow.
The nature and extent of fractured rock is such that it follows the Slope Aquifer conceptual
model set forth by LeGrand. Bedrock aquifers in the piedmont are hydraulically connected to
the overlying transition zone and surficial aquifers, and they all slope toward a discharge
location (river or lake).
In the piedmont, fractures are irregular and discontinuous, not tending to form a continuous
conduit.
41

Mounding
Deep fractures
Pumping
Duke's Response to Comments
42

66
Unsaturated
zone
Water table
AV
Core of
„ depression
tA
Off-site pumping
Concern Defined
This concern refers to the extent to which off site
wells influence the prevailing groundwater flow
direction, potentially drawing coal ash contaminants
toward residences
The net effect of any pumping by offsite wells on hydraulic gradient is captured by the
existing network of monitoring wells and the model.
Off site well quality data do not reveal any impacts by boron or other EPAAppendix III
constituents.
Off site wells pump at depths much greater than the depth of ash basins or the impact of the
ash basins.
43

Allen Steam Station
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary
M

Concentrations of Boron (ug/L) in Bedrock Wells
. OF
'010
J6,
Tt
M7,
rw
IVA,
Allen Steam Station
Y3. 1.
,lux
--- ------------------------
11
45

Belews Creek Steam Station
! •. r M o
�'
Off-site wells
S� _tel. ,�►Aj
p
IL
5 -
Off-site well
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary
�v
Groundwater flow
direction
S� _tel. ,�►Aj
p
IL
5 -
Off-site well
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary

Belews Creek Steam Station
Concentrations of Boron (ug/L) in Bedrock Wells
? ? - 1, ,s-ic -
1
yt 1 r
• _ a 1 f��
�F- r+A' � k X31 • I r /��.yy� nne3�+n
1 1
1
r r'.
i� 1 -
i
47

Belews Creek Steam Station
Concentrations of TDS (ug/L) in Bedrock Wells
Al
V
s
6 z
w
r Y r
k
r r
Y r
e �
o e e
s_
f
r � r
1 7 r
•� Y _ t y
48

Buck Steam Station
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary

Concentrations of Boron (uci/L) in Bedrock Wells
0
Buck Steam Station
50

Cliffside Steam Station
Off-site wells
.. is
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary
�o

Cliffside Steam Station
Concentrations of Boron (ug/L) in Bedrock Wells
52

Cliffside Steam Station
Concentrations of Sulfate (ug/L) in Bedrock Wells
--------------
tZi� �. r• 11f
1 t`r J
5
:' ssLf�r 1 L
t
\ - .. / - ,:"tip .��., .. • ,..:,Y I '.'_:. t a'-'�. .._ \
Nr) J
_ i w.a. . __ I BP l• � '
II111�
- - - Y • rl , It tea e �" ! r 4� .✓'te!> x 1,.�J ...
+ i ,y
f
ti
. L
/
wl
t
t
i
1
1
53

Marshall Steam Station
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
�\ Model Boundary
Off-site well
*Non -potable water well located on Marshall Steam Station property has been omitted
54

�r 0 ..
any ' �„ - ;�'�"'•�+-•--rr-t.:;,t�� - r �. '+� "
� -•� ;:,5 -�.(PH I GSE L 1.. y� - � .,.
DEMbtiITICJN -
'ILI6PILL� BG-26R .
<50 Lr (,50111
ES
ASN
BASIN-
- NDFIL � -
'
if
A0-15
,MJ9 .r .L,�2.
.
PV STRUCTURAL IOd
FILL
r.i .
MW-14BR %
25J f42J)
AB!5BR
<50-11i,50U Y -
DRY"ASN' '
'. LANDFILL
A3-68R'
(PHASE I)
RSH AB-16R
_ - BASIN 120(121)'-
- '
BZBR
FGD RESIDUE 50U 1,50U7,
LANDFILL { r
j'V,
VVA
i

Roxboro Steam Electric Plant
Well Capture Zone
Ash Basin Boundary
Groundwater Flow Direction
M

Roxboro Steam Electric Plant
Concentrations of Boron (ug/L) in Bedrock Wells
raw -0313W 1&-
^=y 2310 (22901
GYPSUM
PAG
Lr '¢''� ~ i
GMw45'
-
<50{N51 �71�081N5) Gw-01'
A
Mw -096R
' ABMw-07BR'I-
<59I<50;
1989
559 (9741
',+1
MVV.11BR'
SEMI-ACTIVE
`,BASIN
/ I
i<50j
1973 ACTIVE
ASH BASIN
11-- Mw-04BR'
MW-156Ry�
J' r
DO15 DUr}R-' -�
,draw-1eea +_
--.
57
-'ABMw.04BR'
I
AgRr
f.11i.OQ6459
_
AHM41P03BFa
ABM
(< 591
501. 501
50
11
GMW-07- _ ___ _____
__J
I<591 A13N4yy-p1BR�
n_
-t7�
1
M850 [N6[
�UMIVY-09�
W _. ►
79p
[sE
n- _
1973 ACTIVE
ASH BASIN
11-- Mw-04BR'
MW-156Ry�
J' r
DO15 DUr}R-' -�
,draw-1eea +_
--.
57

Duke's Response to Comments
Mounding
Deep fractures
Pumping
Depth of CSA wells versus receptor wells
58

Depth of CSA wells versus receptor wells
Concern Defined
The concern is that off site wells are typically
installed at depths much greater than those
installed on site.
The purpose of the CSA was to characterize the vertical and horizontal extent of impacts of
ash basin management. These impacts do not extend deeper.
The installed monitoring wells are located between the ash basin source and any potential
receptor, including off site wells. If there was an impact at greater depth, then the bedrock
wells would have captured this influence.
In the piedmont, the bedrock aquifer is hydraulically connected to overlying
transitional/surficial aquifers.
Coal ash constituents are not driven by density (i.e., they do not sink like DNAPL) but rather
move by lateral advection and dispersion 59

Duke's Response to Comments
Mounding
Deep fractures
Pumping
Depth of CSA wells versus receptor wells
Geochemical effects
60

1.4
1.2
1
0.8
0.6
0.4
0.2
w 0
-0.2
-0.4
-0.6
-0.8
_1
H2CrO4
02 / H2O
HCrOy
3+
Cr Cr(OHI2+ Cr042"
Cr(OH)2+
Cr(OH)3
Gr(OH)Z
HZO / HZ
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
pH
Geochemical effects
Concern Defined
The concern is that changes in Eh/pH, because of operational
activity (capping, dewatering, etc.), will result in greater/different
releases of soluble constituents from ash or from soil. In the case
of soil, the concern is that while the constituents may be naturally
occurring, they are being released because of site activity.
Actual site pH/Eh conditions are relatively stable. Data indicate that sites are generally
acidic and oxidizing.
Potential corrective action scenarios do not create the basis for dramatic changes in
geochemistry as controlled by Eh and pH.
The magnitude of such changes is such that it would not materially affect the CSA
conclusions. For example, the direction of travel remains away from off site wells.
Asheville's peat bogs notwithstanding, these sites do not have hydrocarbons which would
give rise to significant oxidation/reduction reactions.
61

Duke's Response to Comments
Mounding
Deep fractures
Pumping
Depth of CSA wells versus receptor wells
Geochemical effects
Saturated Ash
62

ASH STORAGE
FILL
RAB ASH RETIRED ASH
LANDIFILL BASIN DAM
1
`L —INACTIVE ASH
:C - ---V---
BEDROCK
APPROXIMATE EXTENT Of 2L
EXCEEDANCES OF BDRDN
Ash below groundwater table
0
J
Z
m
wLj
EAST Concern Defined
a�
� o
a c3
A
The concern is ash cannot be allowed to remain
�F'VFRA submerged within groundwater, since the ash is
a source of contamination.
Once dewatering begins, much of this concern goes away.
The presence of ash in water does not automatically represent a concern. The submerged
ash must leach and those leached constituents must migrate. If this occurs, it is observed in
monitoring well data.
Also, while the models conservatively presume a constant source concentration, in reality all
leachable material is exhaustible. This is analogous to tea leaves or coffee grounds.
Direction of flow remains the same; modeling incorporates the source location and projects
its impact.
63

Duke's Response to Comments
Mounding
Deep fractures
Pumping
Depth of CSA wells versus receptor wells
Geochemical effects
Saturated Ash
Constituent Modeling
See tables on next slide
64

Modeling Constituents
Constituents selected for the fate and transport models were those:
a) determined to be source -related by professional judgment of the
university led modeling team,
b) with analytical results that exceeded applicable regulatory criteria, and
c) with a distribution that was not suggestive of naturally occurring
conditions
Certain Constituents were not selected for modeling based on one or
more of the following reasons:
a = Not modeled using MODFLOW/MT3DMS. These constituents will be included in the geochemical
modeling.
b = Only isolated exceedances and/or appear to be related to background or non -source related.
c = No 2L Standard exceedances in non-porewater monitoring wells samples.
d = No 2L Standard or IMAC exceedances; not identified as a COL
e = Found in ash and/or but not found in groundwater - ash being dewatered and removed from site.
f = Constituent is not present in ash pore water monitoring wells above the 2L or IMAC Standards
g = Constituent is not present above the 2L Standard or IMAC outside of the compliance boundary
h = There is not a discernable plume of the constituent downgradient from the ash basin(s)
65
i = The constituent is strongly adsorbed (Kd>20 mL/g; R>100) and has very low mobility

Model Constituents: Duke Energy Carolinas
X = COI
XX = C O I
included in CAP Part 1 Modeling.
added to CAP Part 2 Modeling.
66
Duke Energy
Constituents of Interest (COls) Selected for Groundwater Fate and Transport Modeling
DRAFT
COI
Allen
Belews Creek
Buck
Station
Cliffside
Dan River
Marshall
Riverbend
Aluminum
d
c
d
d
d
d
b
Antimony
X
c
X
X
XX
X
X
Arsenic
X
X
c
X
X
X
XX
Barium
X
c
c
XX
d
X
b
Beryllium
c
X
d
XX
d
X
b
Boron
X
X
X
X
X
X
XX
Cadmium
c
b
d
d
d
d
b
Chromium (VI)
X
X
X
X
X
X
XX
Chromium (Total)
X
X
X
X
X
X
X
Chloride
d
X
d
d
d
X
d
Cobalt
X
X
X
X
X
X
XX
Copper
d
c
d
d
d
d
b
Iron
a
a
a
a
a
a
a
Lead
c
c
d
X
d
d
b
Manganese
a
a
a
a
a
a
a
Mercury
c
c
d
c
d
d
b
Molybdenum
d
d
d
d
d
d
b
Nickel
c
c
e
X
d
d
b
Nitrate
d
c
d
d
d
d
b
pH
a
a
a
a
a
a
a
Selenium
X
b
d
d
XX
X
e
Strontium
d
d
d
d
d
d
b
Sulfate
X
b
X
X
X
X
X
TDS
a
a
a
a
a
a
a
Thallium
c
X
c
X
X
X
XX
Vanadium
X
b
X
X
X
X
XX
Zinc
c
c
d
d
d
d
b
X = COI
XX = C O I
included in CAP Part 1 Modeling.
added to CAP Part 2 Modeling.
66

Model Constituents: Duke Energy Progress
Duke Energy
Constituents of Interest (COls) Selected for Groundwater Fate and Transport Modeling
DRAFT
COI
Asheville
Cape Fear
H.F. Lee
Mayo
Roxboro
Sutton
Weatherspoo
n
Aluminum
a, d, f, g
a, d, f, g
a, d, f, g
a, d, f, g
a, d, f, g, h
a, f, g
a, d, f, g, h
Antimony
g, h
g, c
g
b, h
h, b
b, f
d, f, g
Arsenic
a, h, i
h, i, a
X
X
X
X
X
Barium
c, d, f, g
b, f
g, h
b, g, h
b, f, g
c, g
c, g, h,
Beryllium
f, g, h
g
d, f, g
d, f, g
c, g, h
d, f, g
f, g, h
Boron
X
X
X
X
X
X
X
Cadmium
f, h, b
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
Chromium (VI)
a
a
a
a
a
a
a
Chromium (Total)
a, g, h
a
a
a, d, f, g
a, b, f, h
a
a
Chloride
X
f, g
f, g
d, f, g
f, g
f, h
f, g
Cobalt
X
a, h, i
h, i
a, h, i
a, h, i
a, f, h, i
h, a
Copper
c, d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
Iron
a,h
a,h
X
a,h
a,h
a,h
a,h
Lead
c, d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
f, b
g, h
Manganese
a, h
a, h
X
c, h
a, h
a, h
h
Mercury
c, d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
Molybdenum
c, d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
Nickel
f, g, h
g
d, f, g
d, f, g
g, h
d, f, g
f, g, h
Nitrate
f,g,h,
f, h
d, f, g
d, f, g
d, f, g
b, f
d, f, g
pH
a
a
a
a
a
a
a
Selenium
a, f, g
a, b
c
a, f, g, d
a, f, g
a, b, f, g
a
Strontium
c, d, f, g
d, f, g
d, f, g
d, f, g
d, f, g
f, g, d
d, f, g
Sulfate
X
X
f, g
d, f, g
X
f, g
f, h
TDS
X
h
h
h
h
h
h
Thallium
h, i
X
g, h, i
h, i
h, i
f, h
h
Vanadium
a, h, i
a, h, i
a, h, i
a, b, h, i
a, h, i
X
h
Zinc
c, d, f, g
c, h
d, f, g
d, f, g
c, d, f, g
d, f, g
I1i

General Conclusions from the Investigations
for All Stations
Recent groundwater assessment results are consistent with previous
results from historical and routine compliance boundary monitoring
well data
No imminent hazard to human health or the environment has been
identified as a result of groundwater migration from the ash basins
No evidence of off-site impacts to private or public water supply wells
(except at Sutton and Asheville plants where residents will be
provided a water line, some are receiving bottled water)
68

General Conclusions from the Investigations
for All Stations
Minimal difference and benefit is seen for excavation over cap -in-
place in the modeling scenarios
These investigations and conclusions are conservative — no
adjustment was made for background concentrations
Addition of supplemental wells will add resolution to the CSA results
69

Overall Conclusion
Timing of source control action is not critical
Groundwater conditions do not change drastically overtime as indicated
by the groundwater models
Source control produces benefit to the groundwater over time, but
the method of source control does not make a fundamental
difference in groundwater quality over time
If a receptor was determined to be impacted by a pond, a change in
source control would not be a necessity
The first response to an impacted drinking water well would be drinking
water replacement, followed by an investigation and groundwater
remediation
70

Private Well Analysis
Dr. Lisa Bradley, Ph.D., DABT
71

Introduction
Detailed per well screening for the following datasets was performed:
• North Carolina (NC) Department of Environmental Quality (DEQ) Background
Private Well Data
• Duke Energy (Duke) Background Private Well Data
• DEQ Private Well Data
Constituent concentrations in water for each well for each data set were compared to
the following:
• 2L Standards: North Carolina Groundwater 2L Standards and Interim Maximum
Allowable Concentrations (IMACs).
• Federal Drinking Water Standards: USEPA Maximum Contaminant Levels
(MCLs) and Secondary Maximum Contaminant Levels (SMCLs).
• DHHS Screening Levels: North Carolina Department of Health and Human
Services Screening Levels.
• USEPA Risk -Based Screening Levels (RSLs): November 2015.
72

Summary Of DEQ Private Well, DEQ Background, and
Duke Background Sample And Well Counts
Station
Sample/Well Counts
DEQ Private Wells (a)
DEQ (b)
Background
g ound
Duke (c)
Background
Wells
Available
Wells
Sampled
Samples
Allen
142
119
182
7
16
Asheville
20
8
9
0
13
Bel ews Creek
31
24
36
0
11
Buck
101
84
114
7
17
Cape Fear
2
1
1
0
18
Cliffside
26
17
29
0
9
Dan River
0
0
0
0
8
Lee
34
16
29
0
11
Marshall
47
38
57
10
29
Mayo
7
3
5
0
14
Riverbend
1
0
0
0
11
Roxboro
14
11
18
0
26
Sutton
18
10
17
0
13
Weatherspoon
8
2
3
0
2
Total:
451
333
500
1 24
198
W.

Summary of DEQ Private Well Sampling Data
Frequency of
Frequency of
Range of Detected
Frequency Detected Above:
Frequency of Reporting Limits Above:
Frequency of
Detection
Detects Below All
Constituents
Units
Detection (g)
percent
Concentrations
2L (a)
DHHS (b)
MCL (c)
RSL (d)
2L (a)
DHHS (b)
MCL (c)
RSL (d)
Screening Levels
Constituents Listed in Appendix III Detection Monitoring) oftheCCR Rule(e
Boron
ug/L
112 / 500
22%
1.8 - 690
0
0
0
0
0
0
112
Calcium
ug/L
497 / 500
99%
553 246,000
--
--
--
--
--
--
--
--
--
Chloride
mg/L
491 / 499
98%
0.92 - 335
1
1
1
0
0
0
490
pH
su
496 / 496
100%
2.13 - 9.4
256
--
256
0
--
0
240
Sulfate
mg/L
304 / 499
61%
0.15 - 711
7
7
7
0
0
0
297
Total Dissolved Solids
m /L
492 / 494
100%
1 21.3 - 2,040
9
--
9
0
--
0
--
483
Constituents Listed inAppendix IV (Assessment Monitoring) of the CCR Rule (f)
Antimony
ug/L
37 / 500
7%
0.031 - 1.87
2
2
0
0
60
60
23
23
35
Arsenic
ug/L
79 / 500
16%
0.1 - 108
5
5
5
79
0
0
0
421
0
Barium
ug/L
482 / 499
97%
0.46 - 400
0
0
0
0
0
0
0
0
482
Beryllium
ug/L
20 / 500
4%
0.04 - 0.78
0
0
0
0
23
23
23
0
20
Cadmium
ug/L
33 / 500
7%
0.063 - 1.4
0
0
0
0
0
0
0
0
33
Chromium
ug/L
281 / 500
56%
0.176 - 22.1
7
7
0
0
11
11
0
0
274
Cobalt
ug/L
79 / 500
16%
0.03 - 12
35
35
--
3
59
59
--
29
44
Lead
ug/L
380 / 500
76%
0.073 - 75.5
8
8
8
8
0
0
0
0
372
Mercury
ug/L
25 / 499
5%
0.017 - 0.12
0
0
0
0
0
0
0
0
25
Molybdenum
ug/L
167 / 500
33%
0.064 - 20.2
--
1
--
0
--
4
--
0
166
Selenium
ug/L
42 / 500
8%
0.1643 - 3.4
0
0
0
0
0
0
0
0
42
Thallium
u /L
14 / 500
3%
0.057 - 0.24
1
1
0
1
118
118
5
118
13
Constituents Not Identified in the CCR Rule
Vanadium
ug/L
351 / 500
70%
0.197 - 26.5
344
344
--
0
134
134
--
0
7
Aluminum
ug/L
158 / 500
32%
0.0018 - 5,000
--
1
71
0
--
0
9
0
87
Copper
mg/L
424 / 500
85%
0.0002 - 29
4
4
3
4
0
0
0
0
420
Iron
ug/L
199 / 500
40%
14.5 - 8,500
76
16
76
0
2
0
2
0
123
H exa va I ent Ch ro mi u m
ug/L
262 / 484
54%
0.033 - 22.3
--
239
--
0
--
159
--
0
23
Magnesium
ug/L
497 / 500
99%
101 - 61,200
--
--
--
--
--
--
--
--
--
Manganese
ug/L
376 / 500
75%
0.49 - 1,010
39
16
39
5
0
0
0
0
337
Nickel
ug/L
179 / 500
36%
0.18 - 15
0
0
--
0
0
0
--
0
179
Potassium
ug/L
499 / 500
100%
96.1 - 21,200
--
--
--
--
--
--
--
Sodium
ug/L
500 / 500
100%
570 370,000
34
--
0
--
466
Strontium
ug/L
495 / 500
99%
2.3 - 3400
1
--
0
--
0
--
0
494
Zinc
mg/L
413 / 500
83%
0.0021 - 5.26
11
11
1
0
1
1
1
1
402
Alkalinity
mg/L
479 / 494
97%
1 - 376
--
--
--
--
--
--
--
--
--
Bicarbonate
mg/L
451 / 471
96%
1 - 286
Carbonate
mg/L
5 / 473
1%
0 - 42.6
Total Suspended Solids
mg/L
62 / 474
13%
0.4 - 363
Turbidity
NTU
117 / 491
24%
0.15 - 210
Temperature
°C
492 / 492
100%
7.4 - 28.3
Specific Conductance
umhos/cm
493 / 493
100%
4.5 - 1,770
Dissolved Oxygen
mg/L
487 / 490
99%
0.01 - 13
Oxidation Reduction Potentia
mV
415 / 415
100%
-168.4 - 774.7
--
--
--
--
--
--
--
--
Total Number of Analyses:
19,263
Total Number of Exceedances:
805
733
476
100
408
569
63
592
5,666

Summary of DEQ Private Well Sampling Data
75
Frequency of
Range of Detected
Frequency Detected Above:
Frequency of
Detects Below All
Constituents
Detection (g)
Concentrations
2L (a)
DHHS (b)
MCL (c) RSL (d)
Screening Levels
Constituents Listed in Appendix
III Detection Monitoring) of the CCR Rule(e)
Boron
112
/ 500
1.8
- 690
0
0
--
0
112
Calcium
497
/ 500
553
- 246,000
--
--
--
--
--
Chloride
491
/ 499
0.92
- 335
1
1
1
--
490
pH
496
/ 496
2.13
- 9.4
256
--
256
--
240
Sulfate
304
/ 499
0.15
- 711
7
7
7
--
297
Total Dissolved Solids
492
/ 494
21.3
- 2,040
9
--
9
--
483
Constituents Listed in Appendix
IV Assessment Monitoring) of the CCR Rule f
Antimony
37
/ 500
0.031
- 1.87
2
2
0
0
35
Arsenic
79
/ 500
0.1
- 108
5
5
5
79
0
Barium
482
/ 499
0.46
- 400
0
0
0
0
482
Beryllium
20
/ 500
0.04
- 0.78
0
0
0
0
20
Cadmium
33
/ 500
0.063
- 1.4
0
0
0
0
33
Chromium
281
/ 500
0.176
- 22.1
7
7
0
0
274
Cobalt
79
/ 500
0.03
- 12
35
35
--
3
44
Lead
380
/ 500
0.073
- 75.5
8
8
8
8
372
Mercury
25
/ 499
0.017
- 0.12
0
0
0
0
25
Molybdenum
167
/ 500
0.064
- 20.2
--
1
--
0
166
Selenium
42
/ 500
0.1643
- 3.4
0
0
0
0
42
Thallium
14
/ 500
0.057
- 0.24
1 1
1
0
1
13
Constituents Not Identified in the CCR Rule
Vanadium
351
/ 500
0.197
- 26.5
344
344
--
0
7
Aluminum
158
/ 500
0.0018
- 5,000
--
1
71
0
87
Copper
424
/ 500
0.0002
- 29
4
4
3
4
420
1 ron
199
/ 500
14.5
- 8,500
76
16
76
0
123
Hexava I ent Chromi um
262
/ 484
0.033
- 22.3
--
239
--
0
23
Magnesium
497
/ 500
101
- 61,200
--
--
--
--
--
Manganese
376
/ 500
0.49
- 1,010
39
16
39
5
337
Nickel
179
/ 500
0.18
- 15
0
0
--
0
179
Potassium
499
/ 500
96.1
- 21,200
--
--
--
--
--
Sodium
500
/ 500
570
- 370,000
--
34
--
--
466
Strontium
495
/ 500
2.3
- 3400
--
1
--
0
494
Zinc
413
/ 500
0.0021
- 5.26
11
11
1
0
1 402
Total Number of Exceedances:
805
733
476
100
5,666
75

Summary of DEQ Background Private Well
Sampling Data
Frequency of
Frequency of
q Y
Range of Detected
Frequency Detected Above:
Frequency of Reporting Limits Above:
Frequency of
Background
g
Detection
Detects Below All
Threshold Value
Constituents
Units
Detection (h)
Percent
Concentrations
21. (a)
DHHS (b)
MCL (c)
RSL (d)
2L (a) DHHS (b)
MCL (c)
RSL (d)
Screening Levels
(BTV) (g)
Constituents Listed in Ap
endix 111 (Detection Monitoring) of the CCR Rule (e)
Boron
ug/L
6/ 24
25%
5.3 - 135
0
0
0
0
0
0
6
39.87
Calcium
ug/L
24 / 24
100%
1,680 - 74,200
--
--
--
-
--
--
--
100,163
Chloride
mg/L
24 / 24
100%
1.6 - 38
0
0
0
0
0
0
24
43.78
pH
su
24 / 24
100%
5.15 - 7.85
12
--
12
--
--
--
--
8.061
Sulfate
mg/L
17 / 24
71%
2.1 - 186
0
0
0
0
0
0
17
148.4
Total Dissolved Solids
m /L
23 / 24
1 96%
1 51 - 373
1 0
--
0
0
--
0
23
1 481
Constituents Listed in App
endix IV (Assessment Monitoring) of the CCR Rule (f)
Antimony
ug/L
0/ 24
0%
NA
0
0
0
0
0
0
0
0
0
NA
Arsenic
ug/L
2/ 24
8%
4.4 - 4.4
0
0
0
2
0
0
0
22
0
4.4
Barium
ug/L
24 / 24
100%
0.89 77.3
0
0
0
0
0
0
0
0
24
125.1
Beryllium
ug/L
0/ 24
0%
NA
0
0
0
0
0
0
0
0
0
NA
Cadmium
ug/L
0/ 24
0%
NA
0
0
0
0
0
0
0
0
0
NA
Chromium
ug/L
18 / 24
75%
0.51 - 5
0
0
0
0
0
0
0
0
18
3.715
Cobalt
ug/L
0/ 24
0%
NA
0
0
--
0
0
0
--
0
0
NA
Lead
ug/L
18 / 24
75%
0.12 - 3.2
0
0
0
0
0
0
0
0
18
2.384
Mercury
ug/L
0/ 24
0%
NA
0
0
0
0
0
0
0
0
0
NA
Molybdenum
ug/L
6 / 24
25%
0.58 - 4.9
--
0
--
0
--
0
--
0
6
4.059
Selenium
ug/L
2/ 24
8%
0.52 - 0.72
0
0
0
0
0
0
0
0
2
0.72
Thallium
u /L
0/ 24
0%
NA
0
0
0
0
0
0
0
0
0
NA
Constituents Not Identified in the CCR Rule
Vanadium
ug/L
19 / 24
79%
1 - 23.7
19
19
--
0
5
S
--
0
0
24.07
Aluminum
ug/L
5 / 24
21%
12.1 - 213
--
0
3
0
--
0
0
0
2
142.3
Copper
mg/L
21 / 24
88%
0.001 - 0.0161
0
0
0
0
0
0
0
0
21
0.033
Iron
ug/L
6/ 24
25%
57.5 - 1,340
1
0
1
0
0
0
0
0
5
761.5
Hexavalent Chromium
ug/L
12 / 24
50%
0.14 - 4.5
--
12
--
0
--
11
--
0
0
3.168
Magnesium
ug/L
24 / 24
100%
808 - 28,800
--
--
--
--
--
--
--
--
--
31,525
Manganese
ug/L
16 / 24
67%
0.5 - 271
0
1
0
0
0
0
0
0
15
142.9
Nickel
ug/L
6 / 24
25%
0.53 1.8
0
0
--
0
0
0
--
0
6
1.433
Potassium
ug/L
24 / 24
100%
265 - 3,450
--
--
--
--
4,258
Sodium
ug/L
24 / 24
100%
4,610 - 29,900
3
0
21
29,900
Strontium
ug/L
24 / 24
100%
12.2 - 1150
0
--
0
--
0
--
0
24
1,809
Zi nc
mg/L
17 / 24
71%
0.0051 - 0.147
0
0
0
0
0
0
0
0
17
0.0838
Alkalinity
mg/L
24 / 24
100%
7.4 - 226
--
--
--
--
--
--
--
--
--
285.9
Bicarbonate
mg/L
23 / 24
96%
7.4 - 226
308.6
Carbonate
mg/L
0 / 24
0%
NA
NA
Total Suspended Solids
mg/L
4 / 24
17%
4.2 - 20.6
14.32
Turbidity
NTU
4 / 24
17%
2 - 10.6
6.806
Temperature
°C
24 / 24
NA
15.25 - 17.68
18.01
Specific Conductance
umhos/cm
24 / 24
NA
0.053 - 0.9
1.01
Dissolved Oxygen
mg/L
24 / 24
NA
0.32 - 9.86
9.396
Oxidation Reduction Potentia
mV
24 / 24
NA
-63 241
241
Total Number ofAnalyses:1
936
1 Total Number of Exceedances:
32
35
16
2
5
16
0
22
249
7F

Summary of DEQ Background Private Well
ta
77
Sampling
Da
Frequency
of
Range of Detected
Frequency Detected
Above:
Frequency of
Background
Detects Below All
Threshold Value
Constituents
Detection (h)
Concentrations
2L (a)
DHHS (b)
MCL (c)
RSL (d)
Screening Levels
(BN) (g)
Constituents Listed in Appendix III (Detection Monitoring) of the CCR Rule (e)
Boron
6
/
24
5.3
- 135
0
0
--
0
6
39.87
Calcium
24
/
24
1,680
- 74,200
--
--
--
--
--
100,163
Chloride
24
/
24
1.6
- 38
0
0
0
--
24
43.78
pH
24
/
24
5.15
- 7.85
12
--
12
--
--
8.061
Sulfate
17
/
24
2.1
- 186
0
0
0
--
17
148.4
Total Dissolved Solids
23
/
24
51
- 373
0
--
0
--
23
481
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (f)
Antimony
0/
24
NA
0
0
0
0
0
NA
Arsenic
2/
24
4.4
- 4.4
0
0
0
2
0
4.4
Barium
24
/
24
0.89
- 77.3
0
0
0
0
24
125.1
Beryllium
0/
24
NA
0
0
0
0
0
NA
Cadmium
0/
24
NA
0
0
0
0
0
NA
Chromium
18
/
24
0.51
- 5
0
0
0
0
18
3.715
Cobalt
0/
24
NA
0
0
--
0
0
NA
Lead
18
/
24
0.12
- 3.2
0
0
0
0
18
2.384
Mercury
0/
24
NA
0
0
0
0
0
NA
Molybdenum
6
/
24
0.58
- 4.9
--
0
--
0
6
4.059
Selenium
2/
24
0.52
- 0.72
0
0
0
0
2
0.72
Thallium
0/
24
NA
0
0
0
0
0
NA
Constituents Not Identified in the CCR Rule
Vanadium
19
/
24
1
- 23.7
19
19
--
0
0
24.07
Aluminum
5
/
24
12.1
- 213
--
0
3
0
2
142.3
Copper
21
/
24
0.001
- 0.0161
0
0
0
0
21
0.033
Iron
6/
24
57.5
- 1,340
1
0
1
0
5
761.5
HexavaIentChromium
12
/
24
0.14
- 4.5
--
12
--
0
0
3.168
Magnesium
24
/
24
808
- 28,800
--
--
--
--
--
31,525
Manganese
16
/
24
0.5
- 271
0
1
0
0
15
142.9
Nickel
6
/
24
0.53
- 1.8
0
0
--
0
6
1.433
Potassium
24
/
24
265
- 3,450
--
--
--
--
--
4,258
Sodium
24
/
24
4,610
- 29,900
-
3
--
--
21
29,900
Strontium
24
/
24
12.2
- 1150
--
0
--
0
24
1,809
Zinc
17
/
24
0.0051
- 0.147
0
0
0
0
17
0.0838
Total Number of Exceedances:
32
35
16
2
249
ta
77

Summary of Duke Energy Background Private
Well Sampling Data
78
Frequency of
Frequency of
Range of Detected
Frequency Detected Above:
Frequency of Reporting Limits Above:
Frequency of
Background
Detection
Detects Below All
Threshold Value
Constituents
Units
Detection (i)
Percent
Concentrations
21. (a)
DHHS (b)
MCL (c)
RSL (d)
2L (a)
DHHS (b)
MCL (c)
RSL (d)
Screening Levels
(BTV) (g, h)
Constituents Listed in Appendix III (Detection Monitoring) of the CCR Rule (e)
Boron
ug/L
27 / 185
15%
5.1 113
0
0
0
0
0
0
27
113
Calcium
ug/L
185 / 185
100%
14 195,000
--
--
--
--
150,923
Chloride
mg/L
54 / 54
100%
0.62 40
0
0
0
0
0
0
54
47.01
pH
s
52 / 52
100%
4.88 11.7
5
--
5
0
--
0
47
11.7
Sulfate
mg/L
52 / 54
96%
0.26 170
0
0
0
0
0
0
52
275.3
Total Dissolved Solids
mg/L
40 / 40
100%
42 520
1
--
1
0
--
0
39
584.9
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (f)
Antimony
ug/L
94 / 185
51%
0.5 1.5
48
48
0
0
0
0
0
0
46
1.5
Arsenic
ug/L
25 / 185
14%
0.52 14.1
1
1
1
25
0
0
0
160
0
3.968
Barium
ug/L
164 / 185
89%
1.5 486
0
0
0
0
0
0
0
0
164
486
Beryllium
ug/L
6/ 185
3%
0.31 0.5
0
0
0
0
0
0
0
0
6
0.385
Cadmium
ug/L
7/ 185
4%
0.01 1.17
0
0
0
0
0
0
0
0
7
0.345
Chromium
ug/L
31 / 185
17%
0.5 157
3
3
2
0
0
0
0
0
28
157
Cobalt
ug/L
20 / 185
11%
0.58 25.9
15
15
--
2
0
0
--
0
5
25.9
Lead
ug/L
104 / 185
56%
0.12 73.2
5
5
5
5
0
0
0
0
99
73.2
Mercury
ug/L
1/ 185
1%
0.27 0.27
0
0
0
0
0
0
0
0
1
NA
Molybdenum
ug/L
48 / 185
26%
0.52 10.8
--
0
--
0
--
0
--
0
48
14.16
Selenium
ug/L
10 / 185
5%
0.59 1.7
0
0
0
0
0
0
0
0
10
1.135
Thallium
I ug/L
2/ 185
1%
0.354 0.554
1 2
2
0
2
1 0
0
0
0
1 0
0.554
Constituents Not Identified in the CCR Rule
Vanadium
ug/L
106 / 185
57%
0.318 112
106
106
--
1
42
42
--
0
0
127.8
Aluminum
ug/L
93 / 185
50%
5 32,200
--
3
30
2
--
0
0
0
63
32,200
Copper
mg/L
121 / 185
65%
0.0011 0.992
0
0
0
1
0
0
0
0
120
1.443
Iron
ug/L
119 / 185
64%
10 45,000
42
13
42
2
0
0
0
0
77
45,000
Hexava lent Chromi um
ug/L
72 / 115
63%
0.033 73.5
--
61
--
1
--
13
--
0
11
73.5
Magnesium
ug/L
184 / 185
99%
128 46,300
--
--
--
--
88,964
Manganese
ug/L
119 / 185
64%
0.56 4,820
37
13
37
7
0
0
0
0
82
5,915
Nickel
ug/L
37 / 185
20%
0.53 380
1
1
--
0
0
0
--
0
36
380
Potassium
ug/L
185 185
100%
123 - 8,060
--
--
--
--
--
--
9,555
Sodium
ug/L
185 / 185
100%
763 151,000
16
-
0
169
151,000
Strontium
ug/L
180 / 181
99%
1.3 2,210
-
1
--
0
--
0
--
0
179
3,561
Zinc
ug/L
149 / 185
81%
5 2,990
5
5
0
0
0
0
0
0
144
2,990
AI ka I i n i ty
mg/L
NA
NA
NA
-
--
-
--
--
--
--
--
NA
Bicarbonate
mg/L
NA
NA
NA
-
-
NA
Carbonate
mg/L
NA
NA
NA
-
-
-
NA
Tota ISus pendedSol icls
mg/L
6 / 59
10%
5 - 970
-
-
-
46.96
Turbidity
NTU
NA
NA
NA
-
-
-
NA
Temperature
°C
NA
NA
NA
-
-
-
NA
Specific Conductance
umhos/cm
NA
NA
NA
-
-
-
NA
Dissolved Oxygen
mg/L
NA
NA
NA
-
NA
Oxidation Reduction Potential
mV
I NA
NA
I NA
NA
Total Number of Anal ses:
4,995
1 Total Number of Exceedances:
271
293
123
48
42
55
0
160
1,514
78

Summary of Duke Energy Background Private
Well Sampling Data
79
Frequency of
Frequency of
Range of Detected
Frequency Detected Above:
Frequency of
Background
Detection
Detects Below All
Threshold Value
Constituents
Detection
(i)
Percent
Concentrations
2L (a)
DHHS (b)
MCL (c)
RSL (d)
Screening Levels
(BTV) (g, h)
Constituents Listed in Appendix III (Detection Monitoring) of the CCR Rule (e)
Boron
27
/ 185
15%
5.1
113
0
0
0
27
113
Calcium
185
/ 185
100%
14
195,000
--
--
--
--
--
150,923
Chloride
54
/ 54
100%
0.62
40
0
0
0
54
47.01
pH
52
/ 52
100%
4.88
11.7
5
--
5
47
11.7
Sulfate
52
/ 54
96%
0.26
170
0
0
0
52
275.3
Total Dissolved Solids
40
/ 40
100%
42
520
1
--
1
--
39
584.9
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (f)
Antimony
94
/ 185
51%
0.5
1.5
48
48
0
0
46
1.5
Arsenic
25
/ 185
14%
0.52
14.1
1
1
1
25
0
3.968
Barium
164
/ 185
89%
1.5
486
0
0
0
0
164
486
Beryllium
6/
185
3%
0.31
0.5
0
0
0
0
6
0.385
Cadmium
7/
185
4%
0.01
1.17
0
0
0
0
7
0.345
Chromium
31
/ 185
17%
0.5
157
3
3
2
0
28
157
Cobalt
20
/ 185
11%
0.58
25.9
15
15
--
2
5
25.9
Lead
104
/ 185
56%
0.12
73.2
5
5
5
5
99
73.2
Mercury
1/
185
1%
0.27
0.27
0
0
0
0
1
NA
Molybdenum
48
/ 185
26%
0.52
10.8
--
0
--
0
48
14.16
Selenium
10
/ 185
5%
0.59
1.7
0
0
0
0
10
1.135
Thallium
2/
185
1%
0.354
0.554
1 2
2
0
2
1 0
0.554
Constituents Not Identified in the CCR Rule
Vanadium
106
/ 185
57%
0.318
112
106
106
--
1
0
127.8
Aluminum
93
/ 185
50%
5
32,200
--
3
30
2
63
32,200
Copper
121
/ 185
65%
0.0011
0.992
0
0
0
1
120
1.443
Iron
119
/ 185
64%
10
45,000
42
13
42
2
77
45,000
Hexava lent Chromi um
72
/ 115
63%
0.033
73.5
--
61
--
1
11
73.5
Magnesium
184
/ 185
99%
128
46,300
--
--
--
--
--
88,964
Manganese
119
/ 185
64%
0.56
4,820
37
13
37
7
82
5,915
Nickel
37
/ 185
20%
0.53
380
1
1
--
0
36
380
Potassium
185
/ 185
100%
123
8,060
--
--
--
9,555
Sodium
185
/ 185
100%
763
151,000
16
--
169
151,000
Strontium
180
/ 181
99%
1.3
2,210
-
1
--
0
179
3,561
Zinc
149
/ 185
81%
5
2,990
5
5
0
0
144
2,990
Total Number of Exceedances:
271
293
123
48
1,514
79

Summary of Duke Energy and DEQ Combined
Background Private Well Sampling Data
80
Frequency of
Threshold
Frequency of
Range of Detected
Mean
10th
25th
75th
90th
Detection
Median
[Background
Value
Constituents
Units
Detection (c)
Concentrations
Detect
Percentile
Percentile
Percentile
Percentile
Percent
(BTV) (f, g)
Constituents Listed in Appendix III (Detection Monitorin of the CCR Rule
(d)
Boron
ug/L
33 / 209
16%
5.1 135
25.27
5
5
50
50
50
135
Calcium
ug/L
209 / 209
100%
14 195,000
21,237
3,332
7,960
13,700
28,000
44,180
195,000
Chloride
mg/L
78 / 78
100%
0.62 40
7.62
1.67
2.325
4.45
9.8
19
31.42
pH
su
76 / 76
100%
4.88 11.7
6.989
6.16
6.598
6.97
7.38
7.855
11.7
Sulfate
mg/L
69 / 78
88%
0.26 186
13.01
0.534
1.75
3.8
9.975
18.5
72.27
Total Dissolved Solids
m /L
63 / 64
98%
1 42 520
1 147.4
1 62.5
1 89.75
1 125
160
311.9
381.1
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (e)
Antimony
ug/L
94 / 209
4S%
0.5 1.S
0.985
0.5
0.69
1
1
1.1S
1.5
Arsenic
ug/L
27 / 209
13%
0.52 - 14.1
2.794
0.5
0.5
1
1
1.002
4.881
Barium
ug/L
188 / 209
90%
0.89 486
46.47
S
7
20.S
56
114.4
486
Beryllium
ug/L
6 / 209
3%
0.31 - 0.5
0.373
0.2
0.2
1
1
1
0.363
Cadmium
ug/L
7 / 209
3%
0.01 - 1.17
0.279
0.08
0.08
1
1
1
0.323
Chromium
ug/L
49 / 209
23%
0.5 157
7.851
O.S
0.51
5
5
5
157
Cobalt
ug/L
20 / 209
10%
0.58 25.9
3.612
O.S
0.5
0.6
1
1
25.9
Lead
ug/L
122 / 209
58%
0.12 - 73.2
2.818
0.17
0.48
1
1.21
3.018
73.2
Mercury
ug/L
1 / 209
0.5%
0.27 - 0.27
0.27
O.OS
0.05
0.05
0.2
0.2
NA
Molybdenum
ug/L
54 / 209
26%
0.52 - 10.8
2.477
0.5
0.5
1
1
2.12
14.17
Selenium
ug/L
12 / 209
6%
0.52 - 1.7
1.093
0.5
0.5
1
1
1
1.108
Thallium
ug/L
2 / 209
1.0%
0.354 - 0.554
0.454
0.1
0.1
0.2
0.2
0.2
0.554
Constituents Not Identified in the CCR Rule
Vanadium
ug/L
125 / 209
60%
0.318 112
6.041
0.3
0.579
1
3.8
9.864
23.51
Aluminum
ug/L
98 / 209
47%
5 - 32,200
723.1
5
6
10
21
78.68
32,200
Copper
mg/L
142 / 209
68%
0.001 - 0.992
0.0415
0.002
0.0049
0.005
0.018
0.0602
0.143
Iron
ug/L
125 / 209
60%
10 45,000
1356
10
21
50
179
1486
45,000
Hexavalent Chromium
ug/L
84 / 139
60%
0.033 73.5
1.589
0.03
0.0385
0.19
0.6
1.52
73.5
Magnesium
ug/L
208 / 209
100%
128 46,300
5266
816
2,000
3,680
5,940
11,360
19,864
Manganese
ug/L
135 / 209
65%
0.5 4820
120.6
0.818
5
5
28.2
102.8
460.9
Nickel
ug/L
43 / 209
21%
0.53 380
12.82
0.5
0.5
5
5
5
380
Potassium
ug/L
209 / 209
100%
123 8,060
1934
536
1,130
1,740
2,500
3,482
9,451
Sodium
ug/L
209 / 209
100%
763 151,000
10,948
4,500
6,240
8,310
11,400
17,840
151,000
Strontium
ug/L
204 / 205
100%
1.3 2210
176.9
27
60
107
185
343
706
Zi nc
mg/L
166 / 209
79%
0.005 2.99
0.134
0.005
0.006
0.016
0.06
0.225
2.99
Alkalinity
mg/L
24 / 24
100%
7.4 226
79.86
34.19
48.03
66.1
90
166.2
285.9
Bicarbonate
mg/L
23 / 24
96%
7.4 226
81.04
25.03
46.63
66.1
90
166.2
308.6
Carbonate
mg/L
0 / 24
0%
NA
NA
5
5
5
5
5
NA
Total Suspended Solids
mg/L
10 / 83
12%
4.2 970
111
2.5
4.6
5
5
5
38.18
Turbidity
NTU
4 / 24
17%
2 10.6
4.675
1
1
1
1
2.63
6.806
Temperature
°C
24 / 24
100%
15.25 17.68
16.59
16.01
16.37
16.51
16.86
17.18
18.01
Specific Conductance
umhos/cm
24 / 24
100%
0.053 0.9
0.26
0.0912
0.116
0.188
0.295
0.563
1.01
Dissolved Oxygen
mg/L
24 / 24
100%
0.32 9.86
3.291
0.604
1.553
3.025
4.335
5.488
9.396
Oxidation Reduction Potentia
mV
24 / 24
100%
-63 241
134.6
46
110.5
146.5
177
198.3
241
Total Number of Analyses:
5931
80

Summary of Duke Energy and DEQ Combined
Background Private Well Sampling Data
Ali
Background
Frequency of
Range of Detected
Mean
10th
25th
75th
90th
Median
Threshold Value
Constituents
Detection (c)
Concentrations
Detect
Percentile
Percentile
Percentile
Percentile
(BN) (f, g)
Constituents Listed in App endix III (Detection Monitoring) of the CCR Rule (d)
Boron
33 / 209
5.1 - 135
25.27
5
5
50
50
50
135
Calcium
209 / 209
14 - 195,000
21,237
3,332
7,960
13,700
28,000
44,180
195,000
Chloride
78 / 78
0.62 - 40
7.62
1.67
2.325
4.45
9.8
19
31.42
pH
76 / 76
4.88 - 11.7
6.989
6.16
6.598
6.97
7.38
7.855
11.7
Sulfate
69 / 78
0.26 - 186
13.01
0.534
1.75
3.8
9.975
18.5
72.27
Total Dissolved Solids
63 / 64
42 - 520
1 147.4
62.5
1 89.75
1 125
1 160
1 311.9
1 381.1
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (e)
Antimony
94 / 209
0.5 - 1.5
0.985
0.5
0.69
1
1
1.15
1.5
Arsenic
27 / 209
0.52 - 14.1
2.794
0.5
0.5
1
1
1.002
4.881
Barium
188 / 209
0.89 - 486
46.47
5
7
20.5
56
114.4
486
Beryllium
6 / 209
0.31 - 0.5
0.373
0.2
0.2
1
1
1
0.363
Cadmium
7 / 209
0.01 - 1.17
0.279
0.08
0.08
1
1
1
0.323
Chromium
49 / 209
0.5 - 157
7.851
0.5
0.51
5
5
5
157
Cobalt
20 / 209
0.58 - 25.9
3.612
0.5
0.5
0.6
1
1
25.9
Lead
122 / 209
0.12 - 73.2
2.818
0.17
0.48
1
1.21
3.018
73.2
Mercury
1 / 209
0.27 - 0.27
0.27
0.05
0.05
0.05
0.2
0.2
NA
Molybdenum
54 / 209
0.52 - 10.8
2.477
0.5
0.5
1
1
2.12
14.17
Selenium
12 / 209
0.52 - 1.7
1.093
0.5
0.5
1
1
1
1.108
Thallium
2 / 209
0.354 - 0.554
1 0.454
0.1
1 0.1
1 0.2
1 0.2
1 0.2
1 0.554
Constituents Not Identified in the CCR Rule
Vanadium
125 / 209
0.318 - 112
6.041
0.3
0.579
1
3.8
9.864
23.51
Aluminum
98 / 209
5 - 32,200
723.1
5
6
10
21
78.68
32,200
Copper
142 / 209
0.001 - 0.992
0.0415
0.002
0.0049
0.005
0.018
0.0602
0.143
Iron
125 / 209
10 - 45,000
1356
10
21
50
179
1486
45,000
Hexavalent Chromium
84 / 139
0.033 - 73.5
1.589
0.03
0.0385
0.19
0.6
1.52
73.5
Magnesium
208 / 209
128 - 46,300
5266
816
2,000
3,680
5,940
11,360
19,864
Manganese
135 / 209
0.5 - 4820
120.6
0.818
5
5
28.2
102.8
460.9
Nickel
43 / 209
0.53 - 380
12.82
0.5
0.5
5
5
5
380
Potassium
209 / 209
123 - 8,060
1934
536
1,130
1,740
2,500
3,482
9,451
Sodium
209 / 209
763 - 151,000
10,948
4,500
6,240
8,310
11,400
17,840
151,000
Strontium
204 / 205
1.3 - 2210
176.9
27
60
107
185
343
706
Zinc
166 / 209
0.005 - 2.99
0.134
0.005
0.006
0.016
0.06
0.225
2.99
Ali

Comparison of Duke Energy, DEQ and Combined
Background BTVs to USGS NURE BTVs
82
Duke Background
DEQ Background
Duke and DEQ
USGS NURE North
Background
Background
Combined Background
Carolina Background
Threshold Value
Threshold Value
Background Threshold
Threshold Value (BTV)
Constituents
Units
(BTV) (b, c)
(BTV) (b)
Value (BTV) (f)
(a)
Constituents Listed in Appendix III (Detection Monitoring) of the CCR Rule (d)
Boron
ug/L
113
39.87
13S
NA
Calcium
ug/L
150,923
100,163
195,000
NA
Chloride
mg/L
47.01
43.78
31.42
629.4
pH
su
11.7
8.061
11.7
NA
Sulfate
mg/L
275.3
148.4
72.27
NA
Total Dissolved Solids
m /L
584.9
481
381.1
NA
Constituents Listed in Appendix IV (Assessment Monitoring) of the CCR Rule (e)
Anti mony
ug/L
1.5
NA
1.S
NA
Arsenic
ug/L
3.968
4.4
4.881
NA
Barium
ug/L
486
125.1
486
NA
Beryllium
ug/L
0.385
NA
0.363
NA
Cadmium
ug/L
0.345
NA
0.323
NA
Chromium
ug/L
157
3.715
157
NA
Cobalt
ug/L
25.9
NA
25.9
NA
Lead
ug/L
73.2
2.384
73.2
NA
Mercury
ug/L
NA
NA
NA
NA
Molybdenum
ug/L
14.16
4.059
14.17
NA
Selenium
ug/L
1.135
0.72
1.108
NA
Thallium
ug/L
0.554
NA
0.554
NA
82

Comparison of Duke Energy, DEQ and Combined
Background BTVs to USGS NURE BTVs
Constituents
Units
Duke Background
Background
Threshold Value
(BTV) (b, c)
DEQ Background
Background
Threshold Value
(BTV) (b)
Duke and DEQ
Combined Background
Background Threshold
Value (BTV) (f)
USGS NURE North
Carolina Background
Threshold Value (BTV)
(a)
Constituents Not Identified in the CCR Rule
Vanadium
ug/L
127.8
24.07
23.51
42.9
Aluminum
ug/L
32,200
142.3
32,200
13,000
Copper
mg/L
1.443
0.033
0.143
NA
I ron
ug/L
45,000
761.5
45000
NA
Hexava I ent Chromi um
ug/L
73.5
3.168
73.5
NA
Magnesium
ug/L
88,964
31,525
19,864
79,800
Manganese
ug/L
5,915
142.9
460.9
3,758
Nickel
ug/L
380
1.433
380
NA
Potassium
ug/L
9,555
4,258
9,451
NA
Sodium
ug/L
151,000
29,900
151,000
1,079,000
Strontium
ug/L
3,561
1,809
706
NA
Zi nc
mg/L
2.99
0.0838
2.99
NA
Al ka I i n i ty
mg/L
NA
285.9
285.9
NA
Bi ca rbonate
mg/L
NA
308.6
308.6
NA
Carbonate
mg/L
NA
NA
NA
NA
Total Suspended Solids
mg/L
46.96
14.32
38.18
NA
Turbidity
NTU
NA
6.806
6.806
NA
Temperature
°C
NA
18.01
18.01
NA
Specific Conductance
umhos/cm
NA
1.01
1.01
NA
Dissolved Oxygen
mg/L
NA
9.396
9.396
NA
Oxidation Reduction Potential
mV
NA
241
241
NA
W.,

Summary of Background Levels from AWWA and
USEPA UCIVIR3
Background Levels for Boron and Hexavalent
Chromium from American Water Works Association
(AWWA)
Background Levels for Hexavalent Chromium from
USEPA Third Unregulated Contaminant Monitoring
Rule (UCMR3)
AWWA
AWWA
AWWA
Constituents Units
Average
Median
Maximum
Boron (b) ug/L
167.9
40
3321.3
,Hexavalent Chromium (c) ug/L
1.1
0 (d)
52.6
Background Levels for Hexavalent Chromium from
USEPA Third Unregulated Contaminant Monitoring
Rule (UCMR3)
M
Avg Conc
Min
Max
State/Region
Samples
Detects
(ug/L)
(ug/L)
(ug/L)
North Carolina
1519
1019
0.13
0.015
9.1
U.S.
49079
36934
0.58
0.015
97.38
M

J
tw
0
10000
1000
Boron - Background Data Comparison
Boron Background Concentrations
MAX
I MEAN I
10
1
DEQ Private Wells USGS Data Duke Background DEQ Background Duke and DEQ AWWA
(1992 - 2003) Private Wells Private Wells Combined Background
Private Wells
35
85

1000
100
Vanadium - Background Data Comparison
Vanadium Background Concentrations
W-IVA
MEAN
0.1
0.01
DEQ Private Wells USGS Data Duke Background DEQ Background Duke and DEQ NURE North Carolina
(1992 - 2003) Private Wells Private Wells Combined Background 86
Private Wells

Vanadium in Groundwater
Vanadium in Groundwater
u .LUU
❑ .50
0 1
Grid Cell Interpolated Thematic
Grid Cell =1.5 miles
Source:
a as loci
miles
http://portal.ncdenr.org/image/image_gallery?uuid=eb8495e2-b440-4dOa-9998-3d95e6ce5Oab&groupld=38334&t=1391110519151
87

Vanadium and Duke Facilities
Operating plant sites Dan River Mayo
Retired plant sites (Eden, NC) Roxboro (Roxboro, NC)
Belews Creek (Semora, NC)
(Belews Creek, NC)
Buck
(Salisbury, NC)
Marshall
(Terrell, NC),
Asheville a •� 1
(Asheville, NC) t_ •• `---- -'-
-�_ _ _24 '
3
Cliffside (Ble mant, NC) �
(Mooresboro, NC) Riverbend
(Mount Holly, NC)
Weatherspoon
(Lumberton, NC)
J
Cape Fear
(Moncure. NC)
I.F. Lee
(Goldsboro. NC)
Sutton
(Wilmington, NC)
MIJQ15
Plants Outside the Vanadium
Belt
[fan River
Asheville
Cliffside
Cape Fear
Lee
Sutton
I eatherspoon
Plants Within the Vanadium
Belt
M a': o
Roxboro
Be.ews Creek
Buck
Marsha
R verbend 88
A en

Detected Vanadium Results Ordered High to Low
Maximum
California
US
-Based
Private
_
pg/L
pg
Detected
Vanadium
Well Owner ID Plantu L
Detected
Well Vanadium
AL89 Allen 11
Detected
"'""
Value
Drinking
EPA Risk
Detected
"'""
Observed in
Water Notification
Screening
Detected11
Wells: 26.5
Level: 50
Level Value: 86
Detected
Vanadium
u L
pg/L 1.66
1.6
1.5
1.5
1.5
1.5
/L 1.4
1.35
AL94 Allen 25.5
B5
654 Buck 25.6
AL94R Allen 24.9
B33 Buck 11
BC8 Bel ews Creek 23.5
C4 Cliffside 11
AL31 Allen 22.6
AL7 Allen 10.9
B101 Buck 22.4
B92Buck 10.8
C4 Cliffside 22
B44 Buck 10.7
AL59 Allen 19.1
AL11SR Allen 10.6
AL59R Allen 17.1
AL127 Allen 10.6
R014 Roxboro 5.6
B79 Buck 4
814 Buck 2.7
BC27 lelews Cree 1.3
AL48 Allen 16
R011 Roxboro .10.6
AL17 Allen 5.58
B41 Buck 3.9
B77R Buck 2.7
B13R Buck 1.3
B48R Buck 15.6
AL114 Allen 10.5
AL50 Allen 5.5
MR43 Marshall 3.9
MR8 Marshall 2.65
MR6 Marshall 1.29
AL68 Allen 15.4
AL111R Allen 10.4
AL90R Allen 5.5
AL19 Allen 3.84
B66 Buck 2.6
B71 Buck 1.2
B57 Buck 15
AL20 Allen 10.3
B74 Buck 5.5
AL50 Allen 3.7
MR17 Marshall 2.6
MR46 Marshall 1.2
B60 Buck 15
AL34R Allen 10.1
B82 Buck 5.5
AL15 Allen 3.68
MR17R Marshall 2.6
518 Sutton 1.2
B28 Buck 14.4
B84 Buck 10.1
MR2 Marshall 5.5
AL42R Allen 3.6
MR23R Marshall 2.6
B71R Buck 1.1
B59 Buck 14.3
AL58 Allen 10
AL117R Allen 5.4
B83 Buck 3.6
AL95 Allen 2.5
L2 Lee 1.1
B75 Buck 14.1
AL90 Allen 10
AL139 Allen 5.4
AL39 Allen 3.54
813 Buck 2.5
MR14R Marshall 1.1
AL5 Allen 14
AL100 Allen 10
AD Allen 5.38
AL41 Allen 3.5
B34R Buck 2.5
BC18 lelews Cree 1
AL75 Allen 14
B33R Buck 30
AL25R Allen 5.3
AL56R Allen 3.5
B50 Buck 2.5
B16R Buck 1
B2 Buck 14
AL2 Allen 9.9
AL45R Allen 5.3
B79R Buck 3.5
B61R Buck 2.5
B17R Buck 1
B48 Buck 14
MR18 Marshall 9.9
AL66 Allen 5.3
B90 Buck 3.5
MY7 Maya 2.5
MR11 Marshall 1
B55 Buck 14
MR21 Marshall 9.8
AL115 Allen 5.3
AL40R Allen 3.4
AL12 Allen 2.4
BC4 lel ews Cree 0.58
MR20 Marshall 14
AL93R Allen 9.7
AL11R Allen 5.2
AL52R Allen 3.4
AL51R Allen 2.4
W6 eatherspo 0.5
AL75R Allen 13.8
AL73 Allen 9.6
R08R Roxboro 5.2
B67 Buck 3.4
BC4R Bel ews Creek 2.4
BC2 ielews Cree0.4
AL61 Allen 13.6
AL85 Allen 9.6
AL72 Allen 5.1
B81 Buck 3.4
B2R Buck 2.4
S2 Sutton 0.386
AL23R Allen 13.4
AL93 Allen 9.6
AL92R Allen 5.1
B93 Buck 3.4
B26R Buck 2.4
MR16 Marshall 0.36
AL67R Allen 13.3
ALill Allen 9.5
AL117 Allen 5.1
B77 Buck 3.3
L25 Lee 2.4
S4 Sutton 0.352
B76 Buck 13.3
AL70R Allen 9.4
B35 Buck 5.1
AL52 Allen 3.2
MRBR Marshall 2.4
S1 Sutton 0.3
AL39 Allen 13.1
AL73R Allen 9.3
MR44 Marshall 5.1
B49 Buck 3.2
643 Buck 2.3
AL97 Allen 0.28
AL121 Allen 13.1
AL124 Allen 9.3
AL30 Allen 5.07
B78 Buck 3.2
MR30 Marshall 2.24
S8 Sutton 0.271
AL23 Allen 13
AL71 Allen 9.2
AL1 Allen 5
B19 Buck 3.19
AL81 Allen 2.2
S2 Sutton 0.256
AL28 Allen 13
B95 Buck 9.2
AL92 Allen 5
AL40 Allen 3.15
B38 Buck 2.2
AL98 Allen 0.25
AL10OR Allen 12.8
AL103 Allen 9.1
B51 Buck 5
AL119 Allen 3.1
B55R Buck 2.2
S8 Sutton 0.236
AL141 Allen 12.8
AL60 Allen 9
AL142 Allen 4.9
B89 Buck 3.1
MR32R Marshall 2.2
S3 Sutton 0.197
AL39R Allen 12.7
AL83 Allen 9
ALSSR Allen 4.8
R013 Roxboro 3.1
AL78 Allen 2.1
= Station Outside
Vanadium "Belt"
AL21R Allen 12.6
AL102 Allen 9
BC13 lelews Cree 4.8
MY3 Mayo 3.03
B6 Buck 2.1
AL49 Allen 12.6
AL22 Allen 8.9
AL82 Allen 4.7
B42 Buck 3.02
AL14 Allen 2
AL24R Allen 12.5
B22 Buck 8.8
AL140 Allen 4.7
AL16 Allen 3
AL51 Allen 2
ALSSR Allen 12.2
AL77 Allen 8.6
B19R Buck 4.7
AL54 Allen 3
BC4 Bel ews Creek 2
AL91 Allen 12.2
ALSR Allen 8.5
B21R Buck 4.7
B15 Buck 3
B12 Buck 2
AL20R Allen 12
B69 Buck 8.5
B86 Buck 4.7
B88 Buck 3
B12R Buck 2
AL24 Allen 12
AL34 Allen 8.43
MR31 Marshall 4.7
B94 Buck 3
B27 Buck 2
AL67 Allen 12
AL69 Allen 8.4
B62 Buck 4.6
C8 Cliffside 3
MR25R Marshall 2
AL89R Allen 12
AL122 Allen 8.4
B99 Buck 4.6
MR23 Marshall 3
MR35 Marshall 2
AL126 Allen 12
B73 Buck 8.4
AL19R Allen 4.5
MR26 Marshall 3
R03 Roxboro 2
B40 Buck 12
B97 Buck 6.3
AL136 Allen 4.5
AL31R Allen 2.9
MR13 Marshall 1.97
B58 Buck 12
AL48R Allen 6.1
R08 Roxboro 4.5
AL39R Allen 2.9
MR28 Marshall 1.9
MR12 Marshall 12
B39 Buck 6.1
AL6 Allen 4.49
AL42 Allen 2.9
B11R Buck 1.8
AL21 Allen 11.7
B60R Buck 6.1
AL54R Allen 4.4
B100 Buck 2.9
MR18R Marshall 1.8
B29 Buck 115
AL26 Allen 6.08
AL79 Allen 4.4
MR26R Marshall 2.9
MR25 Marshall 1.8
B92 Buck 11.5
AL65 Allen 6
AL11 Allen 4.35
MR29 Marshall 2.9
BC27 Bel ews Creek 1.7
AL113 Allen 11.4
AL99 Allen 6
AL25 Allen 4.3
R01 Roxboro 2.84
B4 Buck 1.7
B96 Buck 11.4
AL118 Allen 6
AL53 Allen 4.3
AL64 Allen 2.8
B4R Buck 1.7
AL110 Allen 11.3
AL96R Allen 5.9
B24 Buck 4.3
B3 Buck 2.8
MR33 Marshall 1.7
AL62 Allen 11.2
B32 Buck 5.9
640R Buck 4.3
B10 Buck 2.8
MR47 Marshall 1.7

100
10
Hexavalent Chromium - Background Data
Comparison
0.01
0.001
DEQ Private Wells Duke Background DEQ Background Duke and DEQ AWWA UCMR3
Private Wells Private Wells Combined Background North Carolina 90
Private Wells

Combined Background Well Correlation Charts -
Boron
&M
700
600
Boron vs. Sulfate
200
100
O
0 100 200 300 400 500 600 700 800
Boron Conamntra ion (pdL)
800
700
600
1,
0
400
�300
200
100
0
0
Calcium vs. Sulfate
50000 100000 1.50000 200000 250000 300000
Calciun Conwntration (ug/L)
Shading indicates values consistent with the identified Background Threshold Values_
Boron vs. Calcium
300000 ,
250000
200000
0
s
150"
`o-
u
E
v 100000
u � �
5=0
.>
o -
0 100 200
300 400 500 600 700 800
Boron Commntration WL)
Shading indicates values consistent with the identified Background Threshold Values.
■ Correlation Charts:
■ The axis for each constituent is the same on all
charts — comparability
■ The green boxes represent the BTV range for the
two constituents being compared
■ Results within the green box are within
background for both constituents
■ Results outside of the green box warrant
additional attention
91

Private Well Charts
All PW Combined
Belews Creek
Buck
Cliffside
Marshall
Sutton
92

800
700
600
= 500
0
0
c 400
`o
u
300
N 200
100
0
0
DEQ Private Well Correlation Charts - Boron
Boron vs. Sulfate
100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Arsenic
75
S 60
120
0
100
U
E
80
0
E
° 30
L
u
c
v 60
o
v
♦
40
Q
0 100 200 300 400 500 600 700 Soo
Boron Concentration (pg/L)
20 -
0 w+--..--��
0 100 200 300 400 500 600 700 800
Boron Concentration (pg/L)
30
Boron vs. Vanadium
25
—220 -
0
c
8 15
0
u
E ♦♦
9 10
A ♦
5
0
0 100
200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Hexavalent Chromium
75
S 60
0
a 45
0
U
E
E
° 30
L
u
c
m 15
x
♦
0
0 100 200 300 400 500 600 700 Soo
Boron Concentration (pg/L)
93
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

DEQ Private Well Correlation Chart - Boron and
Calcium
300000
250000
J
200000
i
O
f0
L
150000
v
O
U
E
v 100000
U
50000
Boron vs. Calcium
Shading indicates values consistent with the identified Background Threshold Values.
94

800
700
600
= 500
0
E 400
uo
u 300
14
200
100
DEQ Private Well Correlation Charts - Calcium
Calcium vs. Sulfate
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
120
100
80
0
w 60
o
u
'c
% 40
Q
20
0
0
Calcium vs. Arsenic
50000 100000 150000 200000 250000 300000
Calcium Concentration (Ng/L)
30
25
20
c
0
`m 15
`o
E
2
10
C
A
5
0
75
60
0
a 45
0
E
E
2 30
u
v
w 15
x
0
0
Calcium vs. Vanadium
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Calcium vs. Hexavalent Chromium
50000 100000 150000 200000 250000 300000
Calcium Concentration (pg/L)
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.
95

Charted DEQ Private Well Results Above BTVs
96
Sample
Concentration
BN (b)
Station
Location (a)
Constituent
(mg/L)
(mg/L)
Allen
AL94
Vanadium
24.9
23.51
AL94R
Vanadium
26.5
23.51
AL115
Sulfate
373
72.27
Asheville
AS11
Sulfate
340
72.27
AS11R
Sulfate
286
72.27
AS13
Sulfate
356
72.27
AS14
Boron
325
135
Belews Creek
BC13
Arsenic
6.8
4.881
BC17
Arsenic
14.1
4.881
BC19
Arsenic
6.1
4.881
BC20
Arsenic
10.8
4.881
BC24
Arsenic
12.1
4.881
BC30
Arsenic
108
4.881
BC32
Arsenic
22.5
4.881
Buck
B61
Sulfate
566
72.27
B61R
Sulfate
711
72.27
B61R
Sulfate
436
72.27
B54
Vanadium
25.6
23.51
B61
Calcium
226000
195000
B61R
Calcium
246000
195000
Cape Fear
--
--
--
--
Cliffside
--
--
--
--
Lee
--
--
--
--
Marshall
--
--
-
--
Mayo
--
--
--
--
Riverbend
--
--
--
--
Roxboro
RO3R
Sulfate
77.6
72.27
Sutton
S2
Boron
690
135
S2
Boron
160
135
S2
Sulfate
160
72.27
S3
Boron
600
135
S3
Sulfate
76
72.27
S4
Boron
180
135
S8
Boron
250
135
S811
Boron
210
135
Weatherspoon
--
-
--
--
96

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NCIAZ AV,
LOADn

800
700
600
9500
c
0
c 400
0
U
a 300
N 200
100
0
0
Belews Creek Correlation Charts - Boron
Boron vs. Sulfate
100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Arsenic
120
100
80
`o
v 45
0
w 60
0
u°
C
N 40
Q
C
A
20
0
0 100 200 300 400 500 600 700 800
Boron Concentration (itg/L)
0
0 100 200 300 400 500 600 700 800
Boron Concentration ({Ig/L)
30
25
20
0
$ 15
0
u
E
° 10
C
M
Boron vs. Vanadium
0 +-
0 100 200 300 400 500 600 700 800
Boron Concentration (Ng/L)
Boron vs. Hexavalent Chromium
75
60
`o
v 45
0
U
E
E
° 30
L
V
C
A
= 15
0
0 100 200 300 400 500 600 700 800
Boron Concentration (itg/L)
98
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

Belews Creek Correlation Chart — Boron and
Calcium
300000
250000
J
200000
Boron vs. Calcium
M01111111f,,
U
50000
U
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
99

800
700
600
9500
`o
5 400
v 300
200
100
Belews Creek Correlation Charts - Calcium
Calcium vs. Sulfate
0
0 50000 100000 150000 200000 250000 300000
Calcium concentration (pg/L)
Calcium vs. Arsenic
75
60
120
`0
v 45
0
100
u
E
i SO
0
30
u
60
'-
o
v
+
0
0 50000 100000 150000 200000 250000 300000
40
Q
+
20
+2
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (pg/L)
30
25
u�
? 20
o
15
o
u
10
5
Calcium vs. Vanadium
Calcium vs. Hexavalent Chromium
75
60
`0
v 45
0
u
E
30
u
v
a 15
x
+
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (pg/L)
100
Shading indicates values consistentwith the identified Background Threshold Values. Shading indicates values consistentwith the identified Background Threshold Values.

ow
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800
700
600
= 500
c
O
c 400
d
O
u
a 300
N 200
100
0
0
Buck Correlation Charts - Boron
Boron vs. Sulfate
120
100
80
a
w 60
o
u
N 40
20
0
0
100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Arsenic
100 200 300 400 500 600 700 800
Boron Concentration (Hg/L)
Shading indicates values consistentwith the identified Background Threshold Values.
30
25
20
0
.q
C
$ 15
0
U
E
0
m 10
c
m
5
0
0
Boron vs. Vanadium
75
m
60
i
co
v 45
0
E
E
30
100 200 300 400 500 600 700 800
Boron Concentration (Hg/L)
Boron vs. Hexavalent Chromium
0 Mqp
0 100 200 300 400 500 600 700 800
Boron Concentration (Ng/L)
Shading indicates values consistent with the identified Background Threshold Values.
102

Buck Correlation Chart - Boron and Calcium
300000
250000
J
2f 200000
Boron vs. Calcium
'x[111111111,
ro
U
50000
U
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
103

Buck Correlation Charts - Calcium
120
100
�e 80
0
V60
c
$ 40
20
0
0
Calcium vs. Arsenic
50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
30
25
20
0
Calcium vs. Vanadium
5
0
75
60
c
0
45
0
U
M
30
u
15
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Calcium vs. Hexavalent Chromium
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
104
Calcium vs. Sulfate
800
700
600
♦
e�
9500
c
o_
c
400
0
V
300
H
200
100
0
0 50000
100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
120
100
�e 80
0
V60
c
$ 40
20
0
0
Calcium vs. Arsenic
50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
30
25
20
0
Calcium vs. Vanadium
5
0
75
60
c
0
45
0
U
M
30
u
15
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Calcium vs. Hexavalent Chromium
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
104

V
ti
DI MPA :
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BuckA-sh
fond
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li
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Cliffside Correlation Charts - Boron
Boron vs. Sulfate
800
100
700
60
0
600
E
500
c
0
114
c
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
400
c
U°
m 300
200
100
0
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Arsenic
120
100
i 80
0
60
0
u
40
a`
20
114
0
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
30
25
20
_o
c
$ 15
c
uo
E
V 10
c
m
5
0
0
Boron vs. Vanadium
75
60
c
0
45
0
u
E
E
r 30
V
i 15
100 200 300 400 Soo 600 700 800
Boron Concentration (µg/L)
Boron vs. Hexavalent Chromium
0 M i i
0 100 200 300 400 Soo 600 700 800
Boron Concentration (µg/L)
107
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

Cliffside Correlation Charts — Boron and Calcium
s W 17171]
250000
J
�f 200000
C
++
M
L-
4-1 ++
v 150000
U
r-
0 O
U
>_
100000
U
50000
Cil
Boron vs. Calcium
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
108

800
700
600
E 500
0
0
c 400
a
o0
u
u 300
N 200
100
0
0
Cliffside Correlation Charts - Calcium
Calcium vs. Sulfate
50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Calcium vs. Arsenic
120
100
80
0
60
0
u
40
20
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (Ng/L)
30
25
20
0
$ 15
0
u
E
m 10
5
0
0
Calcium vs. Vanadium
75
j 60
03
m 45
c
uo
E
E
0 30
15
50000 100000 150000 200000 250000 300000
Calcium Concentration (µg/L)
Calcium vs. Hexavalent Chromium
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (Ng/L)
109
Shading indicatesvalues consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

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800
700
600
= 500
c
c 400
c
0
u
m 300
3
N
200
100
0
0
Marshall Correlation Charts - Boron
Boron vs. Sulfate
100 200 300 400 500 600 700 800
Boron Concentration (Ng/L)
Boron vs. Arsenic
120
100
a 80
0
60
0
c
40
Q
20
0
y
0 100 200 300 400 500 600 700 800
Boron Concentration (WJL)
30
25
20
0
c
m 15
0
u
E
10
C
A
7
5
0
0
Boron vs. Vanadium
75
60
c
45
0
u
E
V 30
0-111
0
100 200 300 400 500 600 700 800
Boron Concentration (Ng/L)
Boron vs. Hexavalent Chromium
100 200 300 400 500 600 700 800
Boron Concentration (Ng/L)
111
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

Marshall Correlation Charts — Boron and Calcium
300000
250000
J
�f 200000
C
O
f6
1
150000
v
c
O
U
E
3
MWIIIZIA;
ca
U
50000
[I]
Boron vs. Calcium
0 100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Shading indicates values consistent with the identified Background Threshold Values.
112

Marshall Correlation Charts - Calcium
Calcium vs. Sulfate
800
100
700
80
2
600
y 60
15
0 0
u
E 500
40
0
Q
E 400
fY
20
0
0
V
300
3
0
N
Calcium Concentration (lAg/L)
200
100
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (WJL)
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (pg/L)
Calcium vs. Arsenic
120
100
25
80
2
20 -.
o
y 60
15
0 0
u
N
40
E
Q
9
10OF
m
20
5 -
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (lAg/L)
Calcium vs. Vanadium
30
25
20 -.
o
15
`o
V
E
9
10OF
m
5 -
0
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (WJL)
113
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

Sutton Well Map
114
MLAI�
MIN
HEW A;E A
k
tee. eA E:IF:,k
Sutton Well Map
114

800
700
600
= 500
`0
c 400
0
U
a 300
200
100
0
0
Sutton Correlation Charts - Boron
Boron vs. Sulfate
100 200 300 400 500 600 700 800
Boron Concentration (µg/L)
Boron vs. Arsenic
120
loo
80
c
0
—
60
c
u0
$
40
Q
0 30
L
20
S 15
0
0 100 200 300 400 500 600 700 800
Boron Concentration (WJL)
30
25
20
Boron vs. Vanadium
n 10
5
Boron vs. Hexavalent Chromium
75
60
`o
E
45
0
E
E
0 30
L
C
a
A
S 15
0
0 100 200 300 400 500 600 700 800
Boron Concentration (WJL)
Data points not available. 115
Shading indicates values consistent with the identified Background Threshold Values. Shading indicates values consistent with the identified Background Threshold Values.

Sutton Correlation Charts - Boron and Calcium
0111111111;
250000
J
�f 200000
Boron vs. Calcium
M111111A1f
to
U
50000
0
Shading indicates values consistent with the identified Background Threshold Values.
116

Sutton Correlation Charts - Calcium
Calcium vs. Sulfate
120
100
80
0
d 60
c
u'
40
Q
20
0
000
Calcium vs. Arsenic
75
60
0
o
8 45
0
E
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (Ng/L)
Shading indicates values consistent with the identified Background Threshold Values.
30
25
20
`o
u 15
`o
u
E
10
C
5
Calcium vs. Vanadium
0 .. ..
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (lig/L)
Calcium vs. Hexavalent Chromium
75
60
0
o
8 45
0
E
E
° 30
L
V
w 15
2
0 -,
0 50000 100000 150000 200000 250000 300000
Calcium Concentration (Ng/L)
Data points not available.
Shading indicates values consistent with the identified Background Threshold Values.

Weight of Evidence and Conclusion
Groundwater Flow:
With the exception of Sutton, groundwater is not flowing from these facilities to areas where private wells are located
Ash Indicators:
Boron and sulfate are the major indicators of a release of coal ash constituents to groundwater
If there is a release, both will be present, at levels above background, their concentrations will be correlated, and
there would be a definable plume
With the exception of Sutton, there are no ash indicators
Lack of exceedances of drinking water standards
Very few MCL exceedances (most are pH and SMCL exceedances)
Very few 2L exceedances (most are pH and vanadium)
Very few DHHS exceedances (most are vanadium and hexavalent chromium)
Very few exceedances of purely risk-based standards
Strong regional database for background and for wells near the facilities — these data sets are very similar:
Of the 14,970 DEQ private well analyses, approximately 7% are above a NC screening level
Of the 544 DEQ background well analyses, approximately 4% are above a NC screening level
Of the 4995 Duke background well analyses, approximately 7% are above a NC screening level
The risk-based drivers for the NC screening levels are vanadium and hexavalent chromium
Comparison of the DEQ private well results for both constituents to background levels from various sources (local,
state, national) indicate that the results are consistent with these background data sets
Conclusion: the private well results are consistent with background and do not exhibit a coal
ash signature 118

Water Supply Well Impacts?
Is there evidence of groundwater impacts to neighboring
water supply wells at these sites?
Groundwater flow is away from neighbors and toward adjacent water bodies
Contaminant plume is away from neighbors and toward adjacent water bodies
Computer modeling indicates that flow is expected to continue moving away
from neighbors
Water supply well results are not characteristic of coal ash sources
Water supply well results reflect results from background locations sampled
across the state by various agencies (e.g., NCDEQ, USGS, UNC, Duke, etc.)
Constituents of concern found in water supply wells are found naturally at
elevated levels in regional soils, groundwater and surface water
Constituents of concern found in water supply wells are often greater at depth
and in upgradient locations indicative of natural occurrence
Prevalence of certain constituents of concern vary with geology
(e.g. hexavalent chromium and vanadium at Piedmont sites versus Sutton)
119

Water Supply Well Impacts?
Allen
Belews
Creek
Buck
Cliffside
Marshall
Roxboro
Flow Away from
✓
✓
✓
✓
✓
✓
Neighbors' Wells?
Plume Away from
✓
✓
✓
✓
✓
✓
Neighbors' Wells?
Modeling Supports
Flow and Transport
✓
✓
✓
✓
✓
✓
Understanding?
Constituents in
Neighbors' Wells Not
✓
✓
✓
✓
✓
✓
Characteristic of
Source?
Constituents in
Neighbors' Wells
✓
✓
✓
✓
✓
✓
Reflective of
Background Locations?

Conclusion
Site investigation concludes groundwater flow is away from receptors
No imminent hazard to human health or the environment
No offsite migration to receptors
No appreciable benefit between excavation and cap -in-place
Duke Energy believes this supports a low risk determination for the
groundwater factors in the CAMA analysis
Low risk provides a range of closure options including Partial
Excavation, Consolidation, Hybrid Cap and Close, Full Excavation,
Sustainable and Innovative Solutions, etc.
Any identified groundwater contamination can be addressed in
multiple ways regardless of closure method (classification) selected
Groundwater corrective action is adaptable to changing site
conditions and receipt of new data
Any remediation plan must be approved by NCDEQ
121

Conclusion
Low risk provides a range of closure options including Partial
Excavation, Consolidation, Hybrid Cap and Close, Full Excavation,
Sustainable and Innovative Solutions, etc.
Any identified groundwater contamination can be addressed in
multiple ways regardless of closure method (classification) selected
Groundwater corrective action is adaptable to changing site
conditions and receipt of new data
All Closure Plans must be approved by NCDEQ
All groundwater Corrective Action Plans must be approved by
NCDEQ
122

� DUKE
ENERGY
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