NC0000396_Seep Management Amendment to CAP_20200831

t DUKE Paul Draovitch
Senior Vice President
\. ENERGY; Environmental,Health&Safety
and Operations Support
526 S. Church Street
Mail Code:EC3XP
Charlotte,NC 28202
[phone]
August 31, 2020
Via Overnight Mail
S. Daniel Smith D C H O W M
Director of Water Resources
North Carolina Department of Environmental Quality
1617 Mail Service Center S E P - 3 2020
Raleigh,NC 27699-1617 -
Rich Bolich DIVISION OF WATER RESOURCES
Section Chief, Groundwater Resources Section DIRECTOR'S OFFICE
North Carolina Department of Environmental Quality
1617 Mail Service Center
Raleigh,NC 27699-1617
Subject: Report Under Special Order by Consent—EMC SOC WQ S17-010
Duke Energy Progress, LLC—Asheville Steam Electric Plant
NPDES Permit NC0000396
Seep Management Amendment to Corrective Action Plan
Dear Messrs. Smith and Bolich:
On behalf of Duke Energy Progress, LLC (DEP), I am submitting to you the Seep Management
Amendment to Corrective Action Plan as required by the Asheville Steam Electric Plant NPDES
Permit NC0000396 Special Order by Consent (SOC), SOC No. S17-010, Section 2.b.3). This
report follows the Seep Characterization Report submitted on June 30, 2020 and addresses
management of non-dispositioned seeps at the Asheville site.
Please direct any questions about this submittal to Chris Hallman at(980) 373-7892.
I certifyunder penalty of law that this document and all attachments were prepared under my
direction or supervision in accordance with a system designed to assure that qualified personnel
properly gather and evaluate the information submitted. Based on my inquiry of the person or
persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief true, accurate,
and complete. I am aware that there are significant penalties for submitting false information,
including the possibility of fine and imprisonment for knowing violations.

Messrs. Smith and Bolich
August 31, 2020
Page 2
Sincerely,
Paul Draovitch
Senior Vice President
Environment, Health& Safety and Operations Support
Duke.Energy
Attachment:
Asheville Steam Electric Plant Seep Management Amendment to Corrective Action Plan
cc: Jim Wells, Duke Energy
Ed Sullivan, Duke Energy
Matt Hanchey, Duke Energy
Richard Baker, Duke Energy
Shannon Langley, Duke Energy
Robert Wylie, Duke Energy
Bryson Allison, Duke Energy
Chris Hallman, Duke Energy
Teresa Williams, Duke Energy
Bob Sledge,NCDENR

4.7
synTerra
SEEP MANAGEMENT AMENDMENT TO
CORRECTIVE ACTION PLAN
ASHEVILLE STEAM ELECTRIC PLANT
46 DUKE ENERGY LANE
ARDEN, NC 28704
AUGUST 31, 2020
PREPARED FOR
Cife;i4 ENERGY
PROGRESS
DUKE ENERGY PROGRESS, LLC
odd D. P in , NCL 2410
Project Manager
Seth Goad
Project Scientist

Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
EXECUTIVE SUMMARY
SynTerra prepared this Seep Management Amendment to the Corrective Action Plan
(CAP) (SynTerra 2016) pertaining to the Asheville Steam Electric Plant(Asheville or
Site) to describe plans for management of identified seeps in a manner that protects
public health, safety and welfare, the environment, and natural resources. This
amendment to the CAP was prepared on behalf of Duke Energy Progress, LLC (Duke
Energy).
Special Order by Consent(SOC)WQ S17-010, approved on October 10, 2018, addresses
management of seeps at the Site during the process of basin closure under the Coal Ash
Management Act of 2014 (CAMA), North Carolina General Statutes (G.S.) 130A-309.200
through 130A-309.231 and the federal Coal Combustion Residuals (CCR) rule, 40 CFR
Parts 257 and 261. Section 2(b)(3) of the SOC states:
No later than August 31, 2020, Duke Energy shall submit a complete and
adequate proposed amendment to the groundwater Corrective Action Plan and/or
Closure Plan as appropriate for the Asheville Facility describing how any seeps
identified in the Seep Characterization Report will be managed in a manner that
will be sufficient to protect public health, safety, and welfare, the environment,
and natural resources...
Findings in the June 2020 Seep Characterization Report (SynTerra 2020) indicate
identified seeps are either candidates to be dispositioned, recently covered under the
Site's National Pollutant Discharge Elimination System Permit (NPDES), or do not
exhibit constituent concentrations that warrant additional corrective action. Duke
Energy continues to implement ash basin closure and corrective action activities that
affect groundwater seepage in a manner that is protective of public health, safety and
welfare, the environment, and natural resources. Completed and ongoing corrective
action and closure activities are summarized below.
Year Closure or Corrective Action Activity
2007 - 2016 Dewatering and excavation of the former 1982 Ash Basin.
2016 - present Dewatering and closure of the 1964 Ash Basin is ongoing. Excavation of
the 1964 Ash Basin is ongoing and planned to be complete by 2022.
2018 - present Groundwater extraction and pH adjustment near the northwest corner
of the 1964 Ash Basin.
2019 - present pH adjustment and supplementary stormwater treatment are being
used to manage groundwater emergence into a stormwater conveyance
ditch located within the former 1982 Ash Basin
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
Evaluation of boron concentrations at seep locations using the Mann Kendall trend test
demonstrates predominantly stable to decreasing trends since implementation of ash
basin closure and groundwater corrective action. In addition to boron, trend tests were
performed on applicable constituents with North Carolina Administrative Code
(NCAC), Title 15A, Subchapter 02B-Surface Water and Wetland Standards (02B).
Overall, the results of the Mann Kendall trend analysis indicate that the system has
been geochemically stable since implementation of ash basin closure and groundwater
corrective action activities, with constituent concentrations remaining stable or
decreasing over time.
In addition to ongoing ash basin closure and corrective action activities, a monitoring
event is recommended following closure of the 1964 basin to determine compliance
with 02B acute and chronic surface water criteria for seeps that are not dispositioned.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress, LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
TABLE OF CONTENTS
SECTION PAGE
EXECUTIVE SUMMARY ES-1
1.0 INTRODUCTION 1-1
1.1 Background 1-1
1.2 Purpose and Scope 1-2
1.3 Previous Reporting 1-2
2.0 OVERVIEW OF SEEPS PROPOSED FOR MANAGEMENT 2-1
2.1 Seeps Associated with the 1964 Ash Basin 2-1
2.2 Seeps Associated with the 1982 Ash Basin 2-2
3.0 PROPOSED SEEP MONITORING PLAN 3-1
3.1 Seeps Associated with the Ash Basins 3-1
3.2 Nature and Extent of Source Related Constituents and Seeps 3-1
3.3 Ash Basin Closure and Corrective Action 3-4
3.4 Effects of Ash Basin Closure and Corrective Action 3-5
3.5 Seep Characterization Conclusions Summary 3-5
3.6 Potential Seep Monitoring 3-6
4.0 REFERENCES 4-1
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
LIST OF FIGURES
Figure 1-1 Site Location Map
P
Figure 2-1 Seeps Associated with the 1964 Ash Basin
Figure 2-2 Seeps Associated with the 1982 Ash Basin
Figure 3-1 Conceptual Site Model- Boron
LIST OF TABLES
Table 3-1 Surface Water Sample Analytical Methods
LIST OF APPENDICES
Appendix A SOC WQ S17-010
Appendix B Mann Kendall Analysis, August 2020
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
LIST OF ACRONYMS
02B North Carolina Administrative Code, Title 15A, Subchapter 02B,
Surface Water and Wetland Standards
02L North Carolina Administrative Code, Title 15A, Subchapter 02L,
Groundwater Standards
µg/L micrograms per liter
BTV background threshold values
CCRs coal combustion residuals
COI constituent of interest
CSA comprehensive site assessment
CAP corrective action plan
DWR Division of Water Resources
EMC Environmental Management Commission
USEPA U.S. Environmental Protection Agency
FGD flue gas desulfurization
IMAC interim maximum allowable concentration
mg/L milligrams per liter
NCAC North Carolina Administrative Code
NCDEQ North Carolina Department of Environmental Quality
NC L.G. North Carolina Licensed Geologist
NPDES National Pollutant Discharge Elimination gSystem
Site Asheville Steam Electric Plant
SOC Special Order by Consent
SOP standard operating procedure
USACE United States Army Corp of Engineers
UT Unnamed Tributary
WOS Waters of the State
WOTUS Waters of the United States
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden, NC SynTerra
1.0 INTRODUCTION
SynTerra prepared this Seep Management Amendment to the Corrective Action Plan
(SynTerra 2016) pertaining to the Asheville Steam Electric Plant (Asheville or Site) to
describe plans to manage identified seeps in a manner that protects public health, safety
and welfare, the environment, and natural resources. This amendment was prepared on
behalf of Duke Energy Progress, LLC (Duke Energy).
1.1 Background
The Asheville Steam Electric Plant began commercial operations as a coal-fired
electrical power plant in 1964. The coal-fired plant was retired on Jan 29, 2020 and a
combinedcycle plant, powered bynaturalgas, is now in operation. The Site is located
P
on 786 acres along the French Broad River in Buncombe County, North Carolina
(Figure 1-1).
The Site is situated on the shore of Lake Julian. Lake Julian was built for cooling water
by damming the flow of Powell Creek on the north side of the Site. A large portion of
Lake Julian borders the east side of the Site. Surface water from the French Broad River
is also pumped into Lake Julian as a supplemental water supply. The water from the
French Broad River enters a stilling area of the lake on the north side of the Plant. Heat
recovery steam generator and cooling tower blowdown process water is discharged to
Outfall-001. Cooling water from the on-Site combustion turbines evaporator system
discharges to Outfall-002. The French Broad River borders I-26 to the west and
southwest of the Site.
Coal was brought onto the Site by rail and tractor-trailer. The coal pile was centrally
located within the Plant, and a series of overhead conveyors distributed the coal. In
2020,when coal-fired power generation at the Plant ceased, and coal pile excavation
activities began.
A flue gas desulfurization (FGD)blowdown constructed wetlands system was installed
in the northeast corner of the 1964 Ash Basin. The FGD treatment wetlands were
removed in 2016. Gypsum was stored and stockpiled within the covered silo and
loaded out as a raw material via truck. Gypsum has been removed from the Site and is
no longer produced.
Two ash basins, designated the 1964 Ash Basin and former 1982 Ash Basin, are situated
directly south and southwest of the former coal-fired Plant and bordered to the
southwest by steep topographic relief and I-26. The former 1982 Ash Basin is no longer
in use and has been completely excavated. The combined cycle plant was constructed
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
within the footprint of the former 1982 Ash Basin. The 1964 Ash Basin is currently
undergoing dewatering and excavation.
Special Order by Consent(SOC) WQ S17-010, approved on October 10, 2018, addresses
management of 25 seeps at the Site during the process of basin closure under the Coal
Ash Management Act of 2014 (CAMA), North Carolina General Statutes (G.S.) 130A-
309.200 through 130A-309.231, and the federal Coal Combustion Residuals (CCR) rule,
40 CFR Parts 257 and 261. The SOC is provided in Appendix A.
1.2 Purpose and Scope
As required in Section 2.b(3) of the SOC, SynTerra is providing this Seep Management
Amendment to describe plans to manage seeps identified in the Seep Characterization
Report (SynTerra 2020c) in a manner that will protect public health, safety, and welfare,
the environment, and natural resources. The Seep Characterization report evaluated
seeps based on the physical status, chemical composition, and jurisdictional
determination. To be considered in this management plan for corrective action, a seep
must:
1) Be non-dispositioned,
2) Constitute, or flow to Waters of the State (WOS) or Waters of the United States
(WOTUS), and
3) Exhibit constituent concentrations that are greater than applicable North
Carolina Administrative Code (NCAC), Title 15A, Subchapter 02B, Surface Water
and Wetland Standards (02B).
1.3 Previous Reporting
Detailed descriptions of previous Site SOC assessments and characterizations are
documented in the following:
• Comprehensive Site Assessment Report—Asheville Steam Electric Plant (SynTerra,
2015).
• Corrective Action Plan Part 1 —Asheville Steam Electric Plant (SynTerra, 2015).
• Corrective Action Plan Part 2 —Asheville Steam Electric Plant (SynTerra, 2016).
• Comprehensive Site Assessment Supplement 1 —Asheville Steam Electric Plant
(SynTerra, 2016).
• Surface Water Evaluation to Assess 15A NCAC 02B .0200 Compliance for
Implementation of Corrective Action Under 15A NCAC 02L .0106(k)and (1) —Asheville
Steam Electric Plant (SynTerra, 2019).
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
• 2019 Annual Seep Report, Asheville Steam Electric Plant (SynTerra 2019).
• EMC SOC WQ S17-010 Re-Assessment Report, Asheville Steam Electric Plant
(SynTerra 2020a)
• 2020 Interim Seep Report, Asheville Steam Electric Plant(SynTerra 2020b).
• Seep Characterization Report,Asheville Steam Plant(SynTerra 2020c).
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC, Asheville Steam Electric Plant,Arden, NC SynTerra
2.0 OVERVIEW OF SEEPS PROPOSED FOR MANAGEMENT
According to the SOC, there are 25 identified seeps located at the Site. Of those 25 seeps,
three seeps (K-02, P-01, and SD-01) were dispositioned at issuance of the SOC. The
seeps identified in the SOC are described below.
2.1 Seeps Associated with the 1964 Ash Basin
Seeps associated with the 1964 Ash Basin are described below and depicted on
Figure 2-1.
Seep ID Description
64E0-01 Easternmost of two engineered drain pipes from 1964 Ash Basin.
Became permitted outfall during National Pollutant Discharge
Elimination System (NPDES) permit renewal. Combined seep flow from
64E0-01, 64E0-02, and 64E0-03 is currently being monitored by
containment system with 90° V-notch weir. Discharge flows into
unnamed tributary, through culvert under I-26, into wetland area
draining to C-01.
64E0-02 Westernmost of two engineered drain pipes from 1964 Ash Basin.
Became permitted outfall during NPDES permit renewal. Combined
seep flow from 64E0-01, 64E0-02, and 64E0-03 is currently being
monitored by containment system with 90° V-notch weir. Discharge
flows into UT, through culvert under I-26, into wetland area draining to
C-01.
64E0-03 Engineered drain from 1964 Ash Basin at black corrugated culvert.
Flow infiltrates downstream into 64E0-01 and 64E0-02 containment
system. Became permitted outfall during NPDES permit renewal.
Combined seep flow from 64E0-01, 64E0-02, and 64E0-03 is currently
being monitored by containment system with 90° V-notch weir.
Discharge flows into UT, through culvert under I-26, into wetland area
draining to C-01.
A-01 Point of drainage to French Broad River from wetland/braided flow west
of I-26. Northernmost sample locations near river.
A-02 Minor seep in wet area just upstream of A-01. Channeled flow drains
toward A-01 location.
B-01 Point of drainage to French Broad River from wetland/braided flow west
of I-26 and south of A-01.
C-01 Point of drainage to French Broad River from wetland/braided flow west
of I-26 and south of B-01.
C-02 Monitoring location of UT below 1964 Ash Basin for effects of general
area seepage; seep is located just east of culvert under I-26. Stream
flow is conveyed into wetland area draining toward C-01 location.
C-03 Seep near base of northwest side of 1964 Ash Basin. Flow drains to
64E0-3, the 1964 engineered outfall collection system. This non-
constructed seep flows to a portion of an NPDES wastewater treatment
system.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC, Asheville Steam Electric Plant,Arden, NC SynTerra
Seep ID Description
C-05 Area of wetness (AOW) near base of northwest side of 1964 Ash Basin.
Flow drains to 64E0-3, the 1964 engineered outfall collection system.
This non-constructed seep flows to a portion of an NPDES wastewater
treatment system.
D-01 Seep to established channel within wetlands west of I-26. Channel
flows to C-01 location.
N-01 Seep to small channel upstream of its confluence with Powell Creek.
Ponded Water F Ponded water near dry channel between locations B-01 and C-01
DD-Pipe French drain below divider dike between 1964 and former 1982 basin.
Flow is into former 1982 basin footprint, which was recently removed
from the NPDES permit. Flow would drain toward M-01 location and
then to sample point at F-01.
SD-01 Storm drain location at north end of Site near Powell Creek.
(dispositioned)
2.2 Seeps Associated with the 1982 Ash Basin
Seeps associated with the 1982 Ash Basin are described below and depicted on
Figure 2-2.
Seep ID Description
E-01 Point of drainage to French Broad River from wetland/braided flow west
of I-26 and south of C-01 drainage.
F-01 Point of drainage to French Broad River from wetland/braided flow west
of I-26 and south of E-01 drainage.
F-02 Point of drainage to French Broad River from wetland/braided flow west
of I-26 and south of F-01 drainage.
F-03 Monitoring location within wetland area west of I-26, at outlet of culvert
under I-26. May be remnant beaver pond. Flows toward F-01 location,
then to French Broad River.
M-01 Monitoring location for coalescence of seep flows prior to entering
culvert under I-26. Flow drains through wetlands to sampling location
F-01 before entering French Broad River.
K-01 Monitoring location of UT below the 1982 Ash Basin dam, just east of
culvert under I-26, conveying flow to wetlands west of I-26. Flows drain
through wetlands past locations F-03 and F-01 before entering French
Broad River.
K-02 Seep emerging southeast of 1982 basin dam. Flow would drain through
(dispositioned) wetlands to sampling location F-01 before entering French Broad River.
P-01 Monitoring site of small drainage channel south of 1982 Ash Basin prior
(dispositioned) to entering culvert beneath I- 26.
82E0-01 Western drain (Drain 1) from 1982 Ash Basin. 1982 Basin has been
excavated and repurposed. Flow would drain to K-01 and F-01 locations.
82E0-02 Eastern drain (Drain 2) from 1982 Ash Basin; east weir. Basin has been
excavated and repurposed. Flow would drain to K-01 and F-01 locations.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
3.0 PROPOSED SEEP MONITORING PLAN
3.1 Seeps Associated with the Ash Basins
With concurrence from the North Carolina Department of Environmental Quality
(NCDEQ) Division of Water Resources (DWR) on seep jurisdictional and dispositional
status, no seeps associated with the 1964 Ash Basin or the former 1982 Ash Basin have
been identified that require additional corrective action. Ash basin closure and
corrective actions implemented by Duke Energy to date are detailed below in Section
3.3. The nature and extent of identified seeps, effects of ongoing ash basin closure and
corrective action activities, and details about potential proposed monitoring are
discussed in the following sections.
3.2 Nature and Extent of Source Related Constituents and Seeps
Based on groundwater data collected through March 2020, constituents of interest
(COIs) associated with the ash basins in groundwater and surface water include:
• Antimony • Cobalt • Strontium
• Arsenic • Iron • Sulfate
• Beryllium • Manganese • Thallium
• Boron • Molybdenum • Total Dissolved Solids (TDS)
• Cadmium • Nickel • Vanadium
• Chloride • Radium
• Chromium • Selenium
Boron concentrations greater than North Carolina Administrative Code (NCAC), Title
15A, Subchapter 02L—Groundwater Classifications and Standards (02L) represent the
extent of affected groundwater(Figure 3-1). Because boron is non-reactive and mobile
in groundwater it has been identified as a leading-edge indicator and representative of
the overall plume that contains other COIs greater than comparison criteria [02L
standard/Interim Maximum Allowable Concentration (IMAC) or background
concentrations, whichever is greater]. Maximum boron concentrations in groundwater
are found near the northwest corner of the 1964 Ash Basin(near the former FGD
treatment wetland) and at the toe of the former 1982 Ash Basin dam (Figure 3-1).
Maximum boron concentration data for each ash basin are summarized below.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden, NC SynTerra
Location of Maximum
15 NCAC Detection Maximum Date of
02L
Constituent standard (pg/L) Detection Maximum
(pg/L) (pg/L) Detection
Well ID Ash Basin
Boron 700 EXT-1 1964 14,500 2/01/2017
Boron 700 MW-06D Former 1982 1,750 12/08/2016
Groundwater downgradient of the 1964 Ash Basin and former 1982 Ash Basin
discharges to a complex of streams and wetlands between I-26 and the French Broad
River. Seep locations relative to the area of affected groundwater are shown on
Figure 3-1. Historical maximum observed concentrations for boron and constituents
with concentrations greater than a 02B standard are summarized in the table below.
15 NCAC Location of Maximum
Total (T) or Detection Maximum Date of
Dissolved (D) 02B .- Detection Maximum
Constituent standard Seep Associated (pg/L) Detection
(pg/L) Location Ash Basin
Boron (T) NE B-01 1964 6,470 03/29/2018
•
Mercury (T) 0.012 82E0-01 1982 0.122 11/16/2015
Selenium (T) 5 PW-F 1964 51 01/28/2020
Cadmium (D) 0.15 N-01 1964 2.13 02/01/2017
Copper (D) 2.7 64E0-03 1964 51.3 11/07/2016
Nickel (D) 16 K-01 1982 303 03/26/2018
Zinc (D) 36 64E0-03 1964 445 09/20/2016
Notes: - --- -- __
pg/L- micrograms per liter
NE - 02B standard not established
mg/L- milligrams per liter
Seep locations 64E0-3, B-01, and PW-F are located downgradient and in the direction of
groundwater flow from the area of maximum observed concentrations in groundwater
associated with the 1964 Ash Basin (EXT-1) (Figure 3-1). Similarly, seeps 82E0-01 and
K-01 are located downgradient and in the direction of groundwater flow from the area
of maximum concentrations associated with the former 1982 Ash Basin dam (MW-06D)
(Figure 3-1). These observations are consistent with the conceptual model, which
describes groundwater flow toward the French Broad River that emerges as seeps and
springs near the base of former ash basin dams and within the streams and wetlands
between I-26 and the French Broad River.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden, NC SynTerra
Analytical results from seep N-01 have consistently indicated that cadmium occurs at
concentrations greater than the 02B standard. There is no indication that cadmium
concentrations associated with seep N-01 are related to ash basin operations.
Supporting lines of evidence include:
• Site topography and groundwater elevation indicate seep N-01 is side-gradient
and not downgradient of the 1964 ash basin, reducing the likelihood of
constituent migration toward the N-01 location.
• Boron, the primary indicator constituent of affected groundwater,has not been
detected at seep N-01 (Figure 16, Appendix B).
• Concentrations trends for constituents with 02B standards (including cadmium)
are stable (no significant trends identified) or decreasing(Appendix B). Stable
trends can indicate the natural system, rather than the dynamic system
associated with ash basins undergoing closure, are the primary influence on this
location.
• The approved groundwater background threshold value (BTV) for cadmium is 1
microgram per liter(µg/L) (Zimmerman to Draovitch, October 2017), similar to
concentrations associated with seep N-01, indicating concentrations of cadmium
are naturally occurring. (Figure 5, Appendix B).
A preliminary comparison of April 2020 seep analytical results with 02B surface water
standards identified three non-dispositioned seep locations with constituents at
concentrations greater than 02B standards. Analytical data from the remaining 18
monitoring locations sampled during the April 2020 seep characterization efforts did
not indicate results greater than 02B surface water standards. Seep locations and
additional information related to analytical results and seep status are summarized in
the table below.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC, Asheville Steam Electric Plant,Arden, NC SynTerra
15NCAC
Seep Constituent 02B Concentration Additional Information
Locations Standard (pg/L)
(pg/L)
82E0-01 pH 6.0-9.0 5.9 pH within the range of
groundwater BTVs.
Mercury 0.012 0.0484 Mercury is not a groundwater
COI for the Site and
concentrations are within the
range of groundwater BTVs.
82E0-02 pH 6.0-9.0 5.6 pH within the range of
groundwater BTVs.
Mercury 0.012 0.192 Mercury is not a groundwater
COI for the Site and
concentrations are within the
range of groundwater BTVs.
PW-F Selenium 5.0 7.16 Ponded Water-F is considered
(COI) non-jurisdictional and does not
flow to WOS or WOTUS and is
under consideration for
dispositioning.
3.3 Ash Basin Closure and Corrective Action
Duke Energy began implementation of ash basin closure in 2007 and groundwater
corrective action in 2018, which contributes to seep management and surface water
protection at the Site. Completed and ongoing ash basin closure and corrective action
activities are summarized in the table below.
Year Closure or Corrective Action Activity
2007 - 2016 Dewatering, excavation and clean closure of the former 1982 Ash
Basin.
2016 - present Dewatering and closure of the 1964 Ash Basin is ongoing. Excavation
of the 1964 Ash Basin is ongoing and planned to be complete by 2022.
2018 - present Groundwater extraction and pH adjustment near the northwest corner
of the 1964 Ash Basin.
2019 - present pH adjustment and supplementary stormwater treatment are being
used to manage groundwater emergence into a stormwater
conveyance ditch associated with the former 1982 Ash Basin
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
3.4 Effects of Ash Basin Closure and Corrective Action
Effects of ash basin closure and corrective action activities have been evaluated with the
Mann Kendall statistical test (Appendix B) to analyze how constituent concentrations at
seep locations have changed since basin closure and groundwater activities have been
implemented. The Mann Kendall trend test evaluates data over time to develop a
statistical conclusion that pertains to trends — increasing, decreasing, or no trend — of
a COI concentration. It should be noted samples collected prior to 2016 were removed
from the analyses so that the analyzed data are reflective of conditions after ash basin
closure and groundwater corrective action activities were initiated.
Results of the Mann Kendall test evaluation indicates the following:
• Trend analysis was performed on 78 constituent-location pairs.
• 96 percent of trends were either stable or decreasing since implementation of
basin closure and groundwater corrective action activities at the Site.
• Two locations (64E0-01 and C-02) indicated increasing boron concentration
trends. Discharge from 64E0-1 and 64E0-2 was historically captured and routed
through the Plant NPDES system. Combined flow from these locations were
recently permitted as Outfall 101 and allowed flow to C-02. This change in
discharge condition likely contributed to observed concentrations at C-02.
Additionally, a statistically significant trend was not identified at 64E0-02, which
conveys similar flow as 64E0-01.
Overall, the results of the Mann Kendall trend analysis indicate that the system has
been geochemically stable since implementation of ash basin closure and groundwater
corrective action activities, with COI concentrations remaining stable or decreasing over
time. The Mann Kendall Analysis report is provided in Appendix B.
3.5 Seep Characterization Conclusions Summary
In order to be considered for corrective action, a seep must:
1) Be non-dispositioned,
2) Constitute, or flow to WOS or WOTUS, and
3) Exhibit constituent concentrations that are greater than applicable 02B surface
water standards.
Seep flows at four locations (K-02, C-03, C-05 and 64E0-03) have been reduced or
eliminated in response to corrective actions that have been implemented and meet the
SOC requirements to be dispositioned.
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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
The vast majority of identified trends for COI concentrations (96%) at seep locations
have now been shown to be stable or decreasing.
A preliminary comparison of April 2020 seep analytical results with 02B surface water
standards identified 19 seeps with concentrations less the 02B standards and three non-
dispositioned seep locations (82E0-01, 82E0-02, and PWF) with constituents at
concentrations greater than 02B standards. The pH levels and mercury concentrations
measured at seeps 82E0-01 and 82E0-02 are within the range of groundwater BTVs.
PW-F is considered non-jurisdictional and does not flow to WOS or WOTUS and meets
the SOC requirements to be dispositioned.
As described in Section 3.3, ash basin closure and corrective action activities are
underway or planned. Based on those activities and the findings presented in the Seep
Characterization Report(SynTerra 2020c) and here in the Seep Management Plan, with
DWR concurrence to disposition seeps, additional corrective action may not be
necessary.
3.6 Potential Seep Monitoring
Non-dispositioned seeps are scheduled to be monitored as required by the SOC
through June 2022. SynTerra recommends an additional monitoring event to determine
compliance with 02B acute and chronic surface water criteria for seeps that are not
dispositioned following closure of the 1964 basin. Select seep locations would be
sampled to allow an assessment of 15A NCAC 02B .0200 compliance.
Samples would be collected in general accordance with the NCDEQ DWR Internal
Technical Guidance: Evaluating Impacts to Surface Water from Discharging Groundwater
Plumes-October 31, 2017. Surface water monitoring would take place at seep locations
identified in the Seep Characterization Report(SynTerra 2020c) that are not
dispositioned by DWR prior to closure of the 1964 basin. Surface water sample
parameters and analytical methods are summarized in Table 3-1.
A summary report including summary tables, figures, and text would be prepared for
submittal to NCDEQ.
Page 3-6

Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
4.0 REFERENCES
SynTerra (2015). Comprehensive Site Assessment Report, Asheville Steam Electric Plant.
SynTerra (2015). Corrective Action Plan Part 1, Asheville Steam Electric Plant.
SynTerra (2016). Corrective Action Plan Part 2, Asheville Steam Electric Plant.
SynTerra (2016). Comprehensive Site Assessment Supplement 1, Asheville Steam Electric
Plant.
SynTerra (2016). Comprehensive Site Assessment Supplement 1, Asheville Steam Electric
Plant.
SynTerra. (2019). Surface Water Evaluation to Assess 15A NCAC 02B .0200 Compliance for
Implementation of Corrective Action Under 15A NCAC 02L .0106 (k) and(1), Asheville
Steam Electric Plant.
SynTerra (2019a). CAMA Annual Interim Monitoring Report, Asheville Steam Electric
Plant.
SynTerra (2019b).Annual Seep Report, Asheville Steam Electric Plant.
SynTerra 2020a . EMC SOC WQS17-010 Re-Assessment Report, Asheville Steam Electric
Y ( ) ,
ep
Plant.
SynTerra (2020b). 2020 Interim Seep Report, Asheville Steam Electric Plant.
SynTerra (2020c). Seep Characterization Report, Asheville Steam Plant.
Page 4-1

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Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
TABLE

TABLE 3-1
SURFACE WATER SAMPLE ANALYTICAL METHODS
ASHEVILLE STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ARDEN, NC
PARAMETER RL UNITS METHOD
FIELD PARAMETERS
pH NA SU Field Water Quality Meter
Specific Conductance _NA µS/cm Field Water Quality Meter
Temperature NA °C Field Water Quality Meter
Dissolved Oxygen NA mg/L Field Water Quality Meter
Turbidity ,NA NTU Field Water Quality Meter
INORGANICS(total and dissolved)
Aluminum 0.005 mg/L EPA 200.7 or 6010D
Antimony 0.001 mg/L EPA 200.8 or 6020B
Arsenic 0.001 mg/L EPA 200.8 or 6020E
' Barium 0.005 mg/L EPA 200.7 or 6010D
' Beryllium 1 pg/I EPA 200.8 or 6020E
Boron 0.05 mg/L EPA 200.7 or 6010D
Cadmium (low level) 0.1 pg/I EPA 200.8 or 6020B
Chromium 0.001 mg/L EPA 200.8 or 6020E
Cobalt 0.001 mg/L EPA 200.8 or 6020B
Copper 0.001 mg/L EPA 200.8 or 6020E
Hexavalent Chromium 0.00003 mg/L EPA 218.7
Iron 0.01 mg/L EPA 200.7 or 6010D
Lead (low level) 0.2 pg/I EPA 200.8 or 6020B
Manganese 0.005 mg/L EPA 200.7 or 6010D
Mercury (low level) 0.0005 pg/L EPA 1631E
Molybdenum 0.001 mg/L EPA 200.8 or 6020B
' Nickel 0.001 mg/L EPA 200.8 or 6020E
Selenium 0.001 mg/L EPA 200.8 or 6020E
Silver (low level) 0.3 pg/I EPA 200.8 or 6020E
Strontium 0.005 mg/L EPA 200.7 or 6010D
Thallium (low level) 0.0002 mg/L EPA 200.8 or 6020B
Vanadium (low level) 0.0003 mg/L EPA 200.8 or 6020E
Zinc 0.005 mg/L EPA 200.7 or 6010D
ANIONS/CATIONS/OTHER
Alkalinity (as CaCO3) 5 mg/L SM 2320B
Bicarbonate 5 mg/L SM 2320E
Calcium 0.01 mg/L EPA 200.7
Carbonate 5 mg/L SM 2320E
Chloride 0.1 mg/L EPA 300.0 or 9056A
Fluoride 100 pg/I EPA 300.0 or 9056A
Hardness NA mg/L as CaCO, EPA 200.7
Magnesium 0.005 mg/L EPA 200.7 or 6010D
Nitrate + Nitrite 0.01 mg-N/L EPA 353.2
Potassium 0.1 mg/L EPA 200.7
Methane 0.01 mg/L RSK - 175
Sodium 0.05 mg/L EPA 200.7
Sulfate 0.1 mg/L EPA 300.0 or 9056A _
Sulfide 0.1 mg/I SM 4500 S2 D
Total Dissolved Solids 25 mg/L SM 2540C
Total Organic Carbon 0.1 mg/L SM5310C/EPA9060A
Total Suspended Solids 2.5 mg/L 2540D
Prepared by: Checked by:aa
Notes:
1. Inorganics analyzed for total and dissolved(0.45 micron)concentrations.
2. NA indicates not applicable.
3. RL indicates laboratory reporting limit.
Page 1 of 1

Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
APPENDIX A
SOC WQ S 17-010

{1 ty♦J
*41W• ,
NORTH CAROLING
ROY COOPER Environmental Quality
Governor
MICHAEL S.REGAN
secretary
L1NDA CULPEPPER
Interim Director
October 10, 2018
Mr. Paul Draovitch, Senior Vice President EHS
Duke Energy
526 S. Church Street
Mail Code EC3XP
Charlotte, NC 28202
Subject: SPECIAL ORDER BY CONSENT
SOC No. S17-010
Duke Energy Progress, LLC
Asheville Plant
NPDES Permit NC0000396
Buncombe County
Dear Mr. Draovitch:
Attached for your records is a copy of the Special Order by Consent (SOC) approved by the
Environmental Management Commission and signed by the Chairman of the Commission on
October 10, 2018.
The terms and conditions of the SOC are in full effect, including those requiring submittal of
written notice of compliance or non-compliance with any schedule date. The following items are
brought to your attention as they pertain to the terms and conditions of the SOC:
• Payment of the upfront penalty is due no later than November 15, 2018.
• Monitoring performed per the terms of the SOC shall commence during the current calendar
quarter(October- December),with results submitted to DWR no later than January 30, 2019.
Subsequent monitoring and reporting shall occur as specified in the SOC.
_E Q�
North Carolina Department of Environmental Quality',Division of Water Resources
512 North Salisbury Street!1617 Mail Ser ice Center Raleigh,North Carolina 27699-1617
919.707.9000

Mr. Paul Draovitch
S 17-010 Transmittal
p.2
Pursuant to North Carolina General Statute 143-215.3D, water quality fees have been revised to
include an annual fee for activities covered under a Special Order by Consent. Duke Energy will
be subject to a fee of$500.00 on a yearly basis while under the Order. The initial fee payment
will be invoiced at a later date, with future fee invoicing done on an annual basis.
If you have any questions concerning this matter,please contact Bob Sledge at [phone].
Sincerely,
Linda Culpepper
Attachment (or
cc: Central Files
NPDES Unit—SOC File
ec: Asheville Regional Office—DWR/Water Quality Regional Operations
Shannon Langley—Duke Energy
Sara Janovitz—EPA Region 4
Jeff Poupart—DWR/WQPS

NORTH CAROLINA
ENVIRONMENTAL MANAGEMENT COMMISSION
COUNTY OF BUNCOMBE
IN THE MATTER OF )
NORTH CAROLINA ) SPECIAL ORDER BY CONSENT
NPDES PERMIT NC0000396 )
HELD BY ) EMC SOC WQ S 17-010
)
DUKE ENERGY PROGRESS, LLC )
Pursuant to the provisions of North Carolina General Statutes (G.S.) 143-215.2, this Special
Order by Consent is entered into by Duke Energy Progress, LLC, hereinafter referred to as Duke
Energy, and the North Carolina Environmental Management Commission, an agency of the State
of North Carolina created by G.S. 143B-282, and hereinafter referred to as the Commission.
Duke Energy and the Commission are referred to hereafter collectively as the "Parties."
1. Stipulations: Duke Energy and the Commission hereby stipulate the following:
a. This Special Order by Consent ("Special Order")addresses issues related to the
elimination of seeps(as defined in subparagraphs e,f,and g below) from Duke
Energy's coal ash basins during the separate and independent process of basin
closure under the Coal Ash Management Act, G.S. 130A-309.200 through 130A-
309.231 ("CAMA") and the Federal Coal Combustion Residuals Rule, 40 CFR
Parts 257 and 261. The Environmental Protection Agency first directed permitting
authorities to consider potential impacts on surface water of seeps from earthen
impoundments in 2010. At that time, Duke Energy began discussions with the
North Carolina Department of Environmental Quality("the Department")
regarding seeps at multiple Duke Energy facilities,including identifying certain
seeps in permit applications and providing data to the Department regarding
seeps. In 2014, Duke Energy provided a comprehensive evaluation of all areas of
wetness and formally applied for NPDES permit coverage of all seeps. Since
2014, Duke Energy has performed periodic inspections and promptly notified the
Department of new seeps and sought NPDES permit coverage where appropriate.
On March 4,2016,the Department issued Notices of Violation("NOVs")to Duke
Energy related to seeps.

EMC SOC WO S 17-010
Duke Energy Progress,LLC
p.2
Decanting (i.e., removal of the free water on the surface of the coal ash basins)
and dewatering(i.e. removal of sufficient interstitial water), which are required
before ash basins can be closed, have already been observed to affect existing
seeps at Duke Energy's Asheville Facility. Removal of remaining coal ash
wastewater is expected to substantially reduce or eliminate the seeps. In order to
accomplish this goal of substantially reducing or eliminating seeps,this Special
Order affords certain relief to Duke Energy related to the non-constructed seeps
(as defined in subparagraphs f and g below), while Duke Energy completes
activities associated with closure of the ash basins at the Asheville Facility.
Constructed seeps(as defined in subparagraphs e and f below) will be addressed
in the NPDES permits. After completion of those activities, for any remaining
seeps, whether constructed or non-constructed, Duke Energy must take
appropriate corrective action as specified more fully below.
b. Duke Energy has been issued a North Carolina NPDES permit for operation of an
existing wastewater treatment works at the following coal fired, electric
generation facility(the"Asheville Facility"):
Receiving
Facility Permit County Issuance Date Water for
Number Primary
Outfall
French
Asheville NC0000396 Buncombe 09/12/2007 Broad
River
c. The Asheville Facility currently operates two-coal fired generating units and two
combustion turbines. A gas-fired combined cycle combustion turbine is currently
under construction and scheduled to begin operation in January 2020. At that
time the coal-fired units will be decommissioned. The Asheville Facility
historically operated two ash basins: the 1964 basin and the 1982 basin. The 1964
basin is currently undergoing excavation and the 1982 basin has been fully
excavated.
d. Wastewater treated at coal-fired electric stations includes water mixed with ash
produced through the combustion of coal for the steam generation process. Ash is
controlled and collected through the use of water, creating a slurry that is
conveyed to impoundments or basins with earthen dike walls. In the ash basin,
the solids separate from the liquid portion,with the resulting supernatant
discharged under the terms of the NPDES permit.

EMC SOC WQ S 17-010
Duke Energy Progress,LLC
p.3
e. The coal ash basins at the Asheville Facility are unlined, having no impermeable
barrier installed along their floors or sides. Earthen basins and dike walls are
prone to the movement of liquid through porous features within those structures
through a process known as seepage. The Asheville Facility exhibits locations
adjacent to, but beyond the confines of, the coal ash basins where seepage of coal
ash wastewater from the coal ash basins may intermix with groundwater, reach
the land surface(or"daylight"), and may flow from that area. Once such seepage
reaches the land surface, it is referred to as a"seep." Each of the seeps identified
at the Asheville Facility and addressed in this Special Order exhibits some
indication of the presence of coal ash wastewater. Both (a)confirmed seeps and
(b)areas identified as potential seeps that were later dispositioned,are identified
in Attachment A.
f: The coal ash impoundments at the Asheville Facility contain constructed features
on or within the dam structures (i.e., toe drains)to collect seepage. This
wastewater is conveyed via a pipe or a constructed channel directly to a receiving
water. These discrete, identifiable, point source discharges are or will be covered
and regulated by the respective NPDES permits and designated as outfalls therein.
The characteristics of these wastewater flows are similar to those discharging
from other permitted outfalls for ash basin effluent. In this Special Order, seeps
that are (1)on or within the dam structures and(2) convey wastewater via a pipe
or constructed channel directly to a receiving water are referred to as "constructed
seeps." Seeps that are not on or within the dam structure or that do not convey
wastewater via a pipe or constructed channel directly to a receiving stream are
referred to as "non-constructed seeps."
g. Non-constructed seeps at the Asheville Facility often exhibit low flow volume
and may be both transient and seasonal in nature, and may, for example,manifest
as an area of wetness that does not flow to surface waters, a point of origin of a
stream feature, or flow to an existing stream feature. These circumstances of the
non-constructed seeps make them difficult to discern, characterize, quantify
and/or monitor as discrete point source discharges. This creates challenges in
permit development and compliance monitoring because it is difficult to
accurately monitor for flow and discharge characterization. Non-constructed
seeps at the Asheville Facility present significant challenges to their inclusion in
NPDES permits as point source discharges, but they do cause or contribute to
pollution of classified waters of the State. Therefore,these non-constructed seeps
are addressed in this Special Order rather than in an NPDES permit.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
p.4
h. A subset of these non-constructed seeps at the Asheville Facility do not flow
directly to surface waters, but flow to some portion of an NPDES permitted
wastewater treatment system. In such instances,the seeps may be referenced in
NPDES permits as contributing flow to a permitted outfall. Any non-constructed
seep that falls within this subset is identified in Attachment A by the following
statement in its description: "This non-constructed seep flows to a portion of an
NPDES wastewater treatment system."
Investigations and observations conducted by the Department and U. S.Army
Corps of Engineers staff have concluded that some seeps emanating from Duke
Energy's coal ash ponds create and/or flow into features delineated as classified
waters of the State or Waters of the United States.
,j. Collectively,the volume of non-constructed seeps is generally low compared to
the volume of historical permitted wastewater discharges at the Asheville Facility.
k. In 2014, Duke Energy conducted a survey of each coal-fired electric generation
station to identify potential seeps from the coal ash surface impoundments. Duke
Energy included all areas of wetness identified around the impoundments as
seeps,and submitted applications to include those seeps in NPDES permits.
Beginning in 2015,Duke Energy has implemented semi-annual surveys to
identify new seeps in the vicinities of the coal ash basins. Additional seeps have
been observed and documented during these surveys and reported to the
Department pursuant to a Discharge Identification Plan mandated by CAMA.
Additional investigation has determined that not all of areas identified in 2014 are
seeps, but, excluding the Sutton Facility, each Duke Energy station, including the
Asheville Facility, does have multiple seeps.
1. The Department issued an NOV to Duke Energy on March 4, 2016 for the seeps
that emanate from the unlined coal ash surface impoundments at the Asheville
Facility.
m. Non-constructed seeps create conditions such that certain surface water quality
standards may not consistently be met at all Duke Energy monitoring sites.
n. The presence of coal ash influenced water in the non-constructed seeps causes or
contributes to pollution of the waters of this State, and Duke Energy is within the
jurisdiction of the Commission as set forth in G.S. Chapter 143, Article 21.
o. A list of seeps identified in the vicinities of the coal ash surface impoundments at
the Asheville Facility, as well as their locations, and the bodies of water those
seeps may flow into(if applicable), can be found in Attachment A to this Special
Order.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
p.5
p. Duke Energy must close the coal ash surface impoundments at all North Carolina
coal-fired electric generating stations in accordance with applicable requirements
set out in CAMA and the Federal Coal Combustion Residuals Rule, requirements
of which are independent of the resolution of seeps addressed in this Special
Order. Duke Energy is required to excavate the Asheville Facility to meet CAMA
requirements. This excavation is required to be complete by August 1, 2022 to
meet the Mountain Energy Act of 2015, SL 2015-110.
q. Decanting of wastewater performed at Duke Energy's coal ash basins is expected
to eliminate or substantially reduce the seeps from the ash basins at the Asheville
Facility.
r. Since this Special Order is by consent,the Parties acknowledge that review of the
same is not available to the Parties in the N.C. Office of Administrative Hearings.
Furthermore,neither party shall file a petition for judicial review concerning the
terms of this Special Order.
2. Duke Energy, desiring to resolve the matters causing or contributing to pollution of the
waters of the State described above,hereby agrees to do the following:
a. Penalties
1) Upfront Penalty. As settlement of all alleged violations due to seepage
at the Asheville Facility,pay the Department, by check payable to the
North Carolina Department of Environmental Quality, a penalty in the
amount of$138,000, calculated based upon$12,000 each for five
constructed seeps identified prior to January 1, 2015 and$6,000 each for
thirteen non-constructed seeps identified prior to January 1, 2015.
A certified check in the amount of$138,000 must be made payable to the
Department of Environmental Quality and sent to the Director of the
Division of Water Resources (DWR)at 1617 Mail Service Center,
Raleigh,North Carolina 27699-1617 by no later than thirty(30) days
following the date on which.this Special Order is approved and executed
by the Commission, and received by Duke Energy.

EMC SOC WQ S 1 7-010
Duke Energy Progress, LLC
p. 6
No penalty shall be assessed for seeps identified after December 31, 2014,
given Duke Energy's inclusion of seeps in permit applications and
compliance with the Discharge Identification Plan required under CAMA.
By entering into this Special Order, Duke Energy makes no admission of
liability, violation or wrongdoing. Except as otherwise provided herein,'
payment of the upfront penalty does not absolve Duke Energy of its
responsibility for the occurrence or impacts of any unauthorized
discharges in the area of the Asheville Facility that may be discovered in
the future, nor does the payment preclude DWR from taking enforcement
action for additional violations of the State's environmental laws.
2) Stipulated Penalties. Duke Energy agrees that unless excused under
paragraph 6, Duke Energy will pay the Department, by check payable to
the North Carolina Department of Environmental Quality, stipulated
penalties according to the following schedule for failure to perform
activities described in paragraphs 2(b,c, and d)and 3, or for failure to
comply with interim action levels listed in Attachment A.
Failure to meet a deadline in the Compliance $1,000.00/day for the first seven
Schedule in 2(b)of this Special Order days; $2,000.00/day thereafter •
Failure to meet any other deadline in this $1,000.00/day for the first seven
Special Order days; $2,000.00/day thereafter
Exceedance of an interim action level listed in $4,500.00 per monitored exceedance
Attachment A j
Monitoring frequency violations $1,000.00 per violation
Discharge from constructed seeps in violation $4,000.00 per day discharge occurs
of terms in paragraph 3 of this Special Order.
Failure to submit, by the deadlines set forth
herein, adequate amendments to groundwater
Corrective Action Plans or Closure Plans to $5,000.00 per day, to a maximum of
address all remaining seeps,whether $1,000,000.00 per electric generating
constructed or non-constructed,through facility.
corrective action as applicable under
paragraph 2(b)(3) of this Special Order.'
As long as Duke Energy remains in compliance with the terms of this Special Order, as
well as CAMA and conditions of any approvals issued thereunder, the Department shall
not assess civil penalties for newly identified seeps.
' See especially paragraph 2(a)(2)excepting newly identified seeps from future penalties under
certain conditions.
Failure to adequately implement any amended Corrective Action Plan or Closure Plan will be
handled in the normal course.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
P. 7
b. Compliance Schedule. Duke Energy shall undertake the following activities in
accordance with the indicated time schedule. No later than fourteen (14)calendar
days after any date identified for accomplishment of any activity, Duke Energy
shall submit to the Director of DWR written notice of compliance or
noncompliance therewith. In the case of compliance, the notice shall include the
date compliance was achieved along with supporting documentation if applicable.
In the case of noncompliance,the notice shall include a statement of the reason(s)
for noncompliance,remedial action(s)taken, and a statement identifying the
extent to which subsequent dates or times for accomplishment of listed activities
may be affected.
As noted in 1(c),the 1982 ash basin has been fully excavated. Within the
footprint of the 1964 ash basin, a modified rim ditch system has been installed to
provide coal ash wastewater treatment. Decanting is largely complete at the 1964
basin, with the exception of wastewater processed through the rim ditch system.
Removal of interstitial water(dewatering)is underway within the 1964 ash basin
in order to complete the required excavation-based closure at Asheville.
1) Within ninety days after the Asheville coal fired generation ceases, and no
later than April 30, 2020, Duke Energy shall conduct a comprehensive
survey of areas downgradient of the ash basins identifying new seeps, and
documenting the physical characteristics of previously documented seeps.
All examinations of seeps must include identification of seeps by
approximate latitude and longitude and date-stamped digital photographs
of their appearance. A report summarizing the findings of the surveys,
including a section analyzing the effect decanting of the basin(s)has on
seep flows, accompanied by copies of the photographs noted above
("Interim Seep Report"), shall be submitted to the Director of DWR no
later than April 30, 2020. This Interim Seep Report must list any seep that
has been dispositioned(as described below) since the Special Order
became effective, including an analysis of the manner of disposition. For
purposes of this Special Order, "dispositioned" includes the following: (1)
the seep is dry for at least three consecutive quarters; (2)the seep does not
constitute, and does not flow to,waters of the State or Waters of the
United States for three consecutive quarters; (3)the seep is no longer
impacted by flow from any coal ash basin as determined by the Director of
DWR in accord with applicable law and best professional judgment; or(4)
the seep has been otherwise eliminated(e.g., through an engineering
solution). If a seep that has been dispositioned through drying up
reappears in any subsequent survey, such a seep will no longer be deemed
dispositioned and can be subsequently re-dispositioned as specified above.
Non-constructed seeps described in paragraph 1(h) of this SOC cannot be
dispositioned through option(2) above.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
P. 8
The determination of whether a seep is dispositioned rests with the
Director of DWR. At, or at any time prior to, submission of the Interim
Seep Report, Duke Energy shall seek formal certification from the
Director of DWR, certifying the disposition of any seep that Duke Energy
has characterized as dispositioned. Any seeps not certified as
dispositioned by the Director of DWR shall not be deemed as
dispositioned.
2) If any seeps(including both constructed and non-constructed seeps)have
not been certified by the Director of DWR as dispositioned (as described
in subparagraph 1) above), Duke Energy shall conduct a characterization
of those seeps.3 Duke Energy shall submit a report on the findings of
these characterizations("Seep Characterization Report")to the Director of
DWR no later than June 30, 2020. The Seep Characterization Report must
include all sampling data for each remaining seep as well as Duke
Energy's evaluation of the jurisdictional status of all seeps at the Asheville
Facility. The determination regarding whether a surface water feature is a
classified water of the State rests with DWR.
3) No later than August 31, 2020, Duke Energy shall submit a complete and
adequate proposed amendment to the groundwater Corrective Action Plan
and/or Closure Plan as appropriate for the Asheville Facility describing
how any seeps identified in the Seep Characterization Report will be
managed in a manner that will be sufficient to protect public health, safety,
and welfare,the environment,and natural resources. This proposed
amendment will go to public comment. Duke Energy shall submit
documentation that the proposed modification has been submitted to the
appropriate division within the Department that has authority for
approving modification of the groundwater Corrective Action Plan and/or
Closure Plan. The content of, and DEQ's review of, an amendment to a
groundwater Corrective Action Plan shall be consistent with Title 15A,
Chapter 2L of the N.C. Administrative Code(specifically including
2L.0106(h)-(o)). The amendment to the Corrective Action Plan and/or
Closure Plans shall be implemented by Duke Energy in accordance with
the deadlines contained therein,as approved or conditioned by the
Department. Failure by Duke Energy to implement the amendment will
be handled in the normal course by the Department in accordance with its
enforcement procedures (i.e., outside this Special Order).
3 If any seep is dispositioned between the time that the Interim Seep Report is submitted and the
time the Seep Characterization Report is submitted,an analysis of the manner of disposition
must be included in the Seep Characterization Report,and Duke Energy must seek certification
of such a disposition from the Director of DWR. Only if such certification is received prior to
the due date of the proposed amendment described in paragraph 2(b)(3)may such a seep,
certified as dispositioned,be omitted from the proposed amendment.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
p.9
For clarity, listed below is a summary of the timetable for the documents due after
completion of steps above:
Document _ Due Date
Interim Seep Report April 30, 2020
Seep Characterization Report June 30, 2020
Proposed amendment to groundwater
Corrective Action Plan and/or Closure August 31, 2020
Plan
4) Termination of Special Order
This
Special Order shall terminate 30 days following the approval of an.
amended groundwater Corrective Action Plan and/or Closure Plan, as
appropriate (if an amendment is submitted in compliance with
subparagraph 2(b)(3)above).
c. Additional Compliance Measures. Duke Energy shall undertake the following
additional compliance measures:
1) If the monitoring of any classified water of the State receiving flow from
seeps regulated by this Special Order indicates exceedance of any interim
action level established by the Special Order, Duke Energy shall increase
monitoring at that location from quarterly to monthly until concentrations
of monitored characteristics return to those observed at the initiation of the
Special Order. If any interim action level established by the Special Order
is exceeded by more than 20% in a single sampling event, or exceeded for
two(2)consecutive monitoring events, in addition to paying the
associated stipulated penalty, Duke Energy shall conduct a re-assessment
of the contributing seep(s), including, but not limited to, evaluation of
proposed remedial actions for treatment and/or control of the seep such
that impacts to the receiving waters are quickly mitigated. A report
compiling the findings of the re-assessment, including proposed remedial
actions, shall be provided to the Director of DWR within 60 days of any
applicable exceedance. Following its review, DWR shall notify Duke
Energy of its concurrence or disapproval of Duke Energy's proposed
remedial actions.
2) During the time this Special Order is in effect, Duke Energy shall provide
quarterly reports on the status of decanting and dewatering work, and
other activities undertaken with respect to closure of its Asheville Facility
to DWR. The quarterly reports are due by April 30, July 30, October 30
and January 30 while this Special Order is in effect. The reports are to be
submitted as follows: one copy must be mailed to the appropriate Regional
Office Supervisor for the Asheville Facility and one copy must be mailed
to the Water Quality Permitting Program, Division of Water Resources,
1617 Mail Service Center, Raleigh, NC 27699-1617.

EMC SOC WQ S17-010
Duke Energy Progress,LLC
p. 10
d. Interim Action Levels.
1) Duke Energy shall perform representative monitoring of waters receiving
flow from non-constructed seeps in accordance with the schedules listed in
Attachments A and B, except as noted in paragraph 2(c)(1) above.
2) Upon the complete execution of this Special Order, with regard to non-
constructed seeps, interim action levels for the receiving waters which are
minor tributaries are hereby established as noted in Attachment A. The
interim action levels are site-specific. Duke Energy shall monitor at
approved sampling sites to ensure interim action levels are met. Interim
action levels shall remain effective in the designated surface waters until
the applicable termination date in paragraph 2(b)(4) is reached.
3) Monitoring associated with seeps covered by this Special Order is exempt
from the electronic reporting requirements associated with NPDES
permits. Results of monitoring required exclusively per the terms of this
Special Order shall be reported to the Director of DWR in a
spreadsheet/worksheet format agreed to by Duke Energy and DWR.
Monitoring data shall be submitted to the Director of DWR in a digital
format no later than 30 days following the end of each calendar quarter for
as long as the Special Order is in effect. Monitoring data shall be sent to
the following email address: [e-mail]. Data from those
sites with monitoring required exclusively per the terms of the Special
Order will be posted on DWR's website to provide the public with the
opportunity for viewing.
3. Duke Energy shall continue to pump discharges from constructed seeps 64E0-1, 64E0-2
and 64E0-3 (toe drains and engineered seep collection) back into the 1964 ash basin until
the commencement of decanting from the rim ditch treatment system. At that time, Duke
Energy may commence direct discharge of wastewater via outfall 101 per the terms of
NPDES permit NC000396.
During the time when Duke Energy is pumping constructed seep flows to the ash basin, it
shall not be liable for the occurrence of discharges from those seeps to surface waters if
such discharge is caused by an unanticipated power outage or mechanical failure of pump
equipment,provided that interruptions of pumping are addressed expeditiously,and in no
instance does a discharge event last for longer than 72 hours.
4. Duke Energy will continue to operate the 1964 coal ash surface impoundment in such a
manner that its performance is optimized, and potential for surface waters to be affected
by seeps is minimized.
5. Duke Energy shall make available on its external website the NPDES permit, this Special
Order and all reports required under this Special Order for the Asheville Facility no later
than thirty(30)days following their effective or submittal dates.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
p. 11
6. Duke Energy and the Commission agree that the stipulated penalties specified in
paragraph 2(a)(2) are not due if Duke Energy satisfies DWR that noncompliance was
caused solely by:
a. An act of God;
b. An act of war;
c. An intentional act or omission of a third party, but this defense shall not be
available if the act or omission is that of an employee or agent of Duke Energy or
if the act or omission occurs in connection with a contractual relationship with
Duke Energy;
d. An extraordinary event beyond the Duke Energy's control, specifically including
any court order staying the effectiveness of any necessary permit or approval.
Contractor delays or failure to obtain funding will not be considered as events
beyond Duke Energy's control; or
e. Any combination of the above causes.
7. Failure within thirty(30) days of receipt of written demand by DWR to pay the stipulated
penalties,or challenge them by a contested case petition pursuant to G.S. 150B-23, will
be grounds for a collection action,which the Attorney General is hereby authorized to
initiate. The only issue in such an action will be whether the thirty(30)days has elapsed.
8. Any non-constructed seeps causing or contributing to pollution of waters of the State
associated with the coal ash impoundments at Duke Energy's Asheville electric
generation station, and listed in Attachment A to this Special Order, are hereby deemed
covered by this Special Order. Any newly-identified,non-constructed seeps discovered
during the time this Special Order is in effect, and timely reported to the Department per
the terms of CAMA and this Special Order, shall be deemed covered by the terms of the
Special Order,retroactive to the time of their discovery. Newly-identified non-
constructed seeps must be sampled for the presence of those characteristics listed in
Attachment B to this Order. Newly-identified non-constructed seeps found to be causing
or contributing to pollution of the waters of the State, with the effect of causing a
violation of water quality standards in surface waters not already referenced in the
Special Order,may require modification of the Special Order to address those
circumstances.
9. Noncompliance with the terms of this Special Order is subject to enforcement action in
addition to the above stipulated penalties, including, but not limited to injunctive relief
pursuant to G.S. 143-215.6C or termination of this Special Order by the Director of DWR
upon ten(10) days' notice to Duke Energy. Noncompliance with the terms of this
Special Order will not be subject to civil penalties in addition to the above stipulated
penalties.

EMC SOC WQ S17-010
Duke Energy Progress, LLC
p. 12
10. This Special Order and any terms or conditions contained herein, hereby supersede any
and all previous Special Orders, Enforcement Compliance Schedule Letters. terms,
conditions, and limits contained therein issued in connection with NPDES permit
NC0000396.
11. This Special Order may be modified at the Commission's discretion, provided the
Commission is satisfied that Duke Energy has made good faith efforts to secure funding,
complete all construction, and achieve compliance within the dates specified. Ln
accordance with applicable law, modification of this Special Order will go to public
notice prior to becoming effective.
12. Failure to pay the up-front penalty within thirty (30) days of execution of this Special
Order will terminate this Special Order.
13. In addition to any other applicable requirement, each report required to be submitted by
Duke Energy under this Special Order shall be signed by a plant manager or a corporate
official responsible for environmental management and compliance, and shall include the
following certification:
I certify under penalty of law that this document and all attachments
were prepared under my direction or supervision in accordance with
a system designed to assure that qualified personnel properly gather
and evaluate the information submitted. Based on my inquiry of the
•
person or persons who manage the system, or those persons directly
responsible for gathering the information,the information submitted
is, to the best of my knowledge and belief, true, accurate, and
complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fine and
imprisonment for knowing violations.
14. This Special Order shall become efTective in accordance with state law, and once
effective, Duke Energy shall comply with all schedule dates, terms, and conditions
herein.

EMC SOC WQ S 17-010
Duke Energy Progress, LLC
p. 13
This Special Order by Consent shall expire no later than June 30, 2022.
For ke Energy Progress, I,LC:
ct (-7 / ( 7
Paul Draovitch Date
Senior Vice President, Environmental, Health& Safety
For the No C oli Environmental Management Commission:
J. D. m , P.E.
Ch r of the Commission Date

Attachment A
517-010
Duke Energy Progress, LLC-Asheville Plant, p.1
Constructed Seeps
Seep ID Approximate Receiving Receiving — —
Number Location Coordinates _ Description Waterbody Waterbody SOC Monitoring Interim Action Levels
Latitude Longitude Classification
Easternmost of two engineered drain pipes
from 1964 Ash Basin. Seep flow is currently Unnamed
being collected and pumped back into ash tributary N/A—Monitoring Seep initially collected at
basin in accordance with the pumping
64E0-01 35.468319 -82.549104 system's design capacity. Any discharge (UT)to Established per engineered outfall and
would flow into UT,through culvert under French Terms of NPDES pumped back to basin;
1-26,into wetland area draining to C-01. Broad Permit afterwards,see C-01
River
Will become permitted outfall in upcoming I
NPDES permit renewal. I i
Westernmost of two engineered drain
pipes from 1964 Ash Basin. Seep flow is I j
currently being collected and pumped back
UT to N/A—Monitoring Seep initially collected at
into ash basin in accordance with the
64E0-02 35.468319 -82.549104 pumping system's design capacity. Any French B Established per engineered outfall and
Broad Terms of NPDES pumped back to basin;
discharge would flow into UT,through River Permit afterwards,see C 01
culvert under 1-26,into wetland area
draining to C-01. Will become permitted
outfall in upcoming NPDES permit renewal.
Engineered drain from 1964 Ash Basin at
black corrugated culvert. Flow infiltrates
downstream. Seep flow is currently being
collected and pumped back into ash basin I UT to N/A—Monitoring Seep initially collected at
in accordance with the pumping system's French Established per engineered outfall and
64E0-03 35.466943 -82.548502 B
design capacity. Any discharge would flow ( Broad Terms of NPDES pumped back to basin;
into UT,through culvert under 1-26,into River Permit afterwards,see C-01
wetland area draining to C-01. Will i •
become permitted outfall in upcoming •
NPDES permit renewal j
*Location previously investigated as a seep. Monitoring has not indicated the presence of coal combustion residuals.
**Seep dispositioned via repair and/or non-flowing condition to potentially reach WOTUS,or other,as noted.
Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order.

Attachment A
S17-010
Duke Energy Progress, LLC-Asheville Plant, p.2
Non-Constructed Seeps
ID Approximate Receiving j
Seep ( Receiving
Location Coordinates Description Waterbody SOC Monitoring Interim Action Level
Number Waterbody
Latitude Longitude Classification
Point of drainage to French Broad Wetlands
Monitoring at location pH 5-10 s.u.
River from wetland/braided flow west draining to
A-01 35.471253 -82.552914 of 1-26. Northernmost of sample French B ( A-01 prior to entering Mercury 50 ng/L
— —
locations near river. Broad River ; f French Broad River Selenium 10 µg/L
Minor seep in wet area just upstream
Wetlands.._ ---- i --- -- --
A-02 35.471155 -82.552596 of A-01. Channeled flow drains draining to B Monitoring at location
See A-01
toward A-01 location. Frenc A-01
Broad River_
Wetlands
Point of drainage to French Broad draining to Monitoring at location Mercury 50 ng/L
B-01 35.468595 -82.551418 River from wetland/braided flow west B I B-01 prior to entering Chlorides 600 mg/L i
French
of 1-26 and south of A-01. French Broad River TDS 2100 mg/L 1
Broad River
Point of drainage to French Broad UT to Monitoring at location Molybdenum 300 mg/L
C-01 35.466042 -82.549701 River from wetland/braided flow west French B C-01 prior to entering TDS 1500 mg/L
L- of 1-26 and south of B-01 j Broad River French Broad River Nickel 50 µg/L
Monitoring location of UT below 1964 ! j
Ash Basin for effects of general areaU
seepage;site is located just east of j to Monitoring at location j
C-02 35.466891 -82.548651 culvert under 1-26. Stream flow is Frere to
B C-01 See C-01
conveyed into wetland area draining Broad River
toward C-01 location.
Seep near base of northwest side of
1964 Ash Basin. Any flow drains to
64E0-3,the 1964 engineered outfall UT to N/A—Monitoring Seep initially collected at
C-03 35.469383 -82.549293 collection system.This non- j French I B Established per Terms of engineered outfall and
constructed seep flows to a portion of Broad River NPDES Permit pumped back to basin;
afterwards,see C-01
an NPDES wastewater treatment
system.
*Location previously investigated as a seep. Monitoring has not indicated the presence of coal combustion residuals.
**Seep dispositioned via repair and/or non-flowing condition to potentially reach WOTUS,or other,as noted.
Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order

Attachment A
517-010
Duke Energy Progress, LLC-Asheville Plant, p.3
Approximate Location i Receiving
Seep ID Receiving
Coordinates Description Waterbody SOC Monitoring Interim Action Level
Number ----- -- Waterbody
Latitude Longitude Classification
AOW near base of northwest side of •
1964 Ash Basin. Any flow drains to i
Seep initially collected at
64E0-3,the 1964 engineered outfall UT to N/A—Monitoring engineered outfall and
C-05 35.46887 1 -82.54915 I collection system.This non- French B Established per Terms g
constructed seep flows to a portion of Broad River 1of NPDES Permit j pumped back to basin;
afterwards,see C-01
an NPDES wastewater treatment
system. i
Seep to established channel within Wetlands
D-01 35.466013 -82.549584 wetlands west of 1-26. Channel flows draining to B Monitoring at location See C-01
to C-Ol location. French 1 C 01
Broad River
f —
i Point of drainage to French Broad Wetlands j Monitoringlocation
g ' draining to at pH 5 10 s.u.
E-01 35.465061 -82.54944 River from wetland/braided flow west French B E-01 prior to entering Nickel 60 ug/L
of 1-26 and south of C-01 drainage. j Broad River French Broad River TDS 600mg/L
• --
pH 5-10 s.u.
Point of drainage to French Broad Wetlands Monitoring at location Copper 15 µg/L
draining to
F-01 35.463581 -82.54854 River from wetland/braided flow west B F-01 prior to entering Mercury 50 ng/L
of 1-26 and south of E-01 drainage, French French Broad River Nickel 100 µg/L
Broad River
TDS 1000 mg/L
Point of drainage to French Broad Wetlands
draining to Monitoring at location I
F-02 35.462533 -82.547499 River from wetland/braided flow west B pH 5-10 s.u.
of 1-26 and south of F-01 drainage. French ( F-02
Broad River j
Monitoring location within wetland Wetlands
area west of 1-26,at outlet of culvert
F-03 35.463114 -82.547177 j under 1-26. May be remnant beaver draining to B Monitoring at location See F-01
French F-01
pond. Flows toward F-01 location, Broad River
then to French Broad River. .
*Location previously investigated as a seep. Monitoring has not indicated the presence of coal combustion residuals.
**Seep dispositioned via repair and/or non-flowing condition to potentially reach WOTUS,or other,as noted.
Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order

Attachment A
517-010
Duke Energy Progress, LLC -Asheville Plant, p.4
Approximate '
Receiving Receiving
Seep ID
Location Coordinates Description
Waterbody Waterbody SOC Monitoring Interim Action Level
Number —
Latitude 1 Longitude Classification
Monitoring location of UT below
the 1982 Ash Basin dam,just east
of culvert under 1-26,conveying UT to
wetlands Monitoring at location
K 01 35..163051 82 545751 Ilow to wetlands west of 1-26. B and French F-01 See F-01
Flows drain through wetlands past Broad River
locations F-03 and F-01 before
entering French Broad River.
5>eep emerging southeast of 1982 Wetlands
** basin dam. Flows through wetlands draining to N/A—Seep N/A—Seep
K-02 35.463581 f -82.544577 , to sampling location F-01 before French B Dispositioned Dispositioned
1 _ • entering French Broad River. i Broad River
Monitoring location for
coalescence of seep flows prior to Wetlands
entering culvert under 1-26. Flow draining to Monitoring at location
M-01 35.464266 -82.546712 ( B See F-01
di ains through wetlands to French F-01
;ampling location F-01 before Broad River
entering French Broad River.
}
Unnamed ,
tributary Monitoring of UT prior
N-01 35.474088 -82.551532 Seep to small channel upstream of (UT)to C to confluence with Cadmium 5 µg/L
its confluence with Powell Creek. 1 Mercury 50 ng/L
Powell Powell Creek
Creek
Monitoring site of small drainage
channel south of 1982 ash basin UT to the
P-01* 35.46185 -82.544625 prior to entering culvert beneath I- French B N/A—Seep N/A—Seep
Dispositioned Dispositioned
26. From sampling—No CCR Broad River
impacts.
Wetlands
Ponded Ponded water near dry channel draining to Monitoring at locations
Water F 35.467232 -82.550521 ! between locations B-01 and C-01 French B B-01 and C-01 See B 01 and C 01
j ( j Broad River I
*Location previously investigated as a seep. Monitoring has not indicated the presence of coal combustion residuals.
**Seep dispositioned via repair and/or non-flowing condition to potentially reach WOTUS,or other, as noted. I
Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order

Attachment A
S17-010
Duke Energy Progress, LLC-Asheville Plant, p.5
Approximate Receiving
Seep ID I Receiving
Location Coordinates Description Waterbody I SOC Monitoring Interim Action Level
Number -- Waterbody
I _ Latitude Longitude Classification
Storm Drain location at north end Powell N/A—Seep N/A—Seep
SD-01* 35.474121 -82.552079 ; of site near Powell Creek. From C
Creek Dispositioned Dispositioned
_ sampling—No CCR impacts.
Western drain(Drain 1)from 1982 t UT to
ash basin. Basin has been wetlands Monitoring at location
82E0-01 35.464058 ! -82.544848 excavated and repurposed. Any draining to B F 01 See F-01
flow would drain to K-01 and F-01 I French
locations. Broad River i 1
Eastern drain(Drain 2)from 1982 UT to i
{ ash basin;east weir. Basin has wetlands
Monitoring at location
82E0-02 35.464058 -82.544848 been excavated and repurposed. draining to ! B See F-01
Any flow would drain to K-01 and French F-01 f
F-01 locations. Broad River
French drain below divider dike
between'64 and past'82 basin. UT to
Flow is into past'82 basin footprint wetlands
Monitoring at location
DD-Pipe 35.466724 -82.544403 which is requested for removal draining to . B F 01 See F-01
from NPDES permit. Flow would French
Idrain toward M-01 location and Broad River
_—__..._.___ ----- _-_—€,then to sample point at F-01. l
Instream Monitoring
Description Receiving Waterbody Receiving Waterbody SOC Monitoring Interim Action Levels
Classification
Instream Monitoring to Upstream&Downstream Monitoring of the N/A—2B Standards
evaluate potential impacts French Broad River B
from seeps French Broad River Apply
*Location previously investigated as a seep. Monitoring has not indicated the presence of coal combustion residuals.
**Seep dispositioned via repair and/or non-flowing condition to potentially reach WOTUS,or other,as noted.
Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order

Asheville Plant- Water Quality Monitoring Locations
,‘,..:1:1:1,..
.a �� Creek
e Julian
N �e��-rj � ,R
if. lb
'' ,. 7,...,„
i -
'''‘\ I * ' ,:- ..4 -0*****' :. ''
u . .
r Eg ti.
Z
\ ' 'I
� or
164 Ash Sin silk, ,, A, . t ,,,,,,,,,t,L, -,I.k.
C 0 1982 Ash;#*'''4.' \ 'Po \ .,`.4 ,,,,I.- '
es m
Basin Site
15.
C?". F01
'
tz
F-02
r
t
I
Upstream Monitoring—French Broad River Stream Monitoring
Downstream Monitoring—French Broad River

SOC S 17-010
Duke Energy Progress, LLC—Asheville Plant
Attachment B
Monitoring Requirements
The following represents the parameters to be analyzed and reported at all monitoring locations
designated within this Special Order.
Parameter Reporting Units Monitoring
P Frequency
TSS mg/L Annually
Oil and Grease mg;L j Annually 1
pH Standard Units(s. u.) Quarterly
Fluoride pg/L Quarterly
Total Mercury [ ng/L Quarterly
Total Barium pg/L Quarterly
Total Zinc pg/L Quarterly
Total Arsenic Ug/L�_� Quarterly
Total Boron € pg/L t Quarterly
Total Cadmium pg/L Quarterly
Total Chromium pg/L Quarterly
Total Copper pg/L Quarterly
Total Thallium ' pg/L Quarterly
Total Lead j pg/L Quarterly
Total Nickel j pg/L _}- Quarterly
Total Selenium pg/L I Quarterly
Nitrate/Nitrite as N mg/L ( Quarterly
Bromides mg/L Quarterly
Sulfates mg/L Quarterly
Chlorides mg/L Quarterly
TDS mg/L Quarterly
Total Hardness mglL Quarterly
Temperature °C Quarterly
Conductivity, pmho/cm pmho/cm Quarterly
Analyses of all monitoring conducted per the terms of this SOC shall conform to the requirements of 15A
NCAC 2B .0505(e)(4)and(5); i.e.,standard methods and certified laboratories shall be used.
l

Seep Management Amendment to Corrective Action Plan August 31,2020
Duke Energy Progress,LLC,Asheville Steam Electric Plant,Arden,NC SynTerra
APPENDIX B
MANN KENDALL ANALYSIS, AUGUST 2020

synTerra
MANN-KENDALL TREND TEST ANALYSIS
AUGUST 2020
PREPARED FOR
,(• DUKE
C' ENERGY
PROGRESS
DUKE ENERGY PROGRESS, LLC

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
TABLE OF CONTENTS
SECTION PAGE
1.0 THE MANN-KENDALL TREND TEST 1-1
2.0 TIME VERSUS CONCENTRATION PLOTS 2-1
3.0 MANN-KENDALL TREND TEST RESULTS 3-1
LIST OF FIGURES
Figure 1 Time vs pH
Figure 2 Time vs total arsenic concentration plot
Figure 3 Time vs dissolved arsenic concentration
Figure 4 Time vs dissolved beryllium concentration plot
Figure 5 Time vs dissolved cadmium concentration
Figure 6 Time vs total chloride concentration
Figure 7 Time vs dissolved chromium concentration
Figure 8 Time vs total chromium concentration
Figure 9 Time vs total hexavalent chromium concentration
Figure 10 Time vs dissolved copper concentration
Figure 11 Time vs total fluoride concentration
Figure 12 Time vs total mercury concentration
Figure 13 Time vs dissolved nickel concentration
Figure 14 Time vs total selenium concentration
Figure 15 Time vs dissolved silver concentration
Figure 16 Time vs total boron concentration
LIST OF TABLES
Table 1 Sampling Locations and Constituents Included in Concentration over Time
Plots
Table 2 Results of Mann-Kendall Trend Test
Page i

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
1.0 THE MANN-KENDALL TREND TEST
The Mann-Kendall trend test evaluates data over time for monotonic trends, where
monotonic indicates a trend that is solely increasing or decreasing. Mann-Kendall is a
useful trend test in that it is non-parametric and does not require normal distribution of
data.
To perform the Mann-Kendall trend test at Asheville, the data must first be processed as
follows:
• Samples taken in the same month must be removed. If more than one sample is
present in a calendar month, the most complete sample will be kept. If samples
are identically complete, the oldest sample is kept. All other samples in that
month will be considered duplicates and removed.
• Non-detects greater than regulatory values are removed.
• Non-detects are treated as the detection limit.
• Samples with turbidity greater than 25 NTU (nephelometric turbidity units) are
removed.
• Samples collected prior to 2016 were removed so that the data is reflective of
only activities and corrective action that occurred after ash basin closure.
Next, the data must meet the following requirements for a Mann-Kendall trend test to
be applicable:
• There must be at least four detect measurements.
• Non-detects must make up less than or equal to 50 percent of measurements.
In a Mann-Kendall trend test, each value is compared to the proceeding values to
calculate whether the value has increased, decreased, or stayed the same over time.
These comparisons are recorded as simply 1 (increasing), -1 (decreasing), or 0 (stayed
the same). These comparisons give an S value, where S indicates the type of trend. A
negative S value indicates a decreasing trend, and a positive S value indicates an
increasing trend. Whether or not these trends are statistically significant is dependent
on the two-sided p value. A p value ranges from 0 to 1 and indicates whether the results
are due to chance or the results are statistically significant. Greater p values indicate a
trend is not statistically significant, and a p value less than 0.1 indicates a statistically
significant trend.
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Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
All Mann-Kendall trend tests are performed in the program RStudio using the
"Kendall" package.
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Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
2.0 TIME VERSUS CONCENTRATION PLOTS
Plots of concentration over time provide a visual representation of possible trends in the
data. All plots can be viewed in Figure 1 to Figure 16. Plots are grouped by constituent,
and within the figure, a plot of concentration over time is displayed for each location
that has data for that constituent. It is important to note that some constituents, such as
dissolved silver, have limited samples in few locations. All locations and constituents
included in these plots can be found in Table 1.
Trends from the Mann-Kendall tests are displayed on plots with colored borders
representing trend conclusions. Blue indicates no trend was present, green indicates a
decreasing trend, yellow indicates an increasing trend, and no color indicates the
constituent-location pair cannot be analyzed for trends due to a lack of detect
measurements. Detect measurements are shown as a black point, whereas non-detect
measurements are shown as an open circle.
Page 2-1

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress,LLC SynTerra
TABLE 1
SAMPLING LOCATIONS AND CONSTITUENTS INCLUDED IN PLOTS OF
CONCENTRATIONS OVER TIME
Sampling Locations Constituents
64E0-01 Total Chloride
64E0-02 Total Arsenic
64E0-03 Total Chromium (VI)
82E0-01 Total Chromium
82E0-02 Total Mercury
A-01 Total Selenium
B-01 Dissolved Arsenic
C-01 Dissolved Beryllium
C-02 Dissolved Cadmium
D-01 Dissolved Chromium
E-01 Dissolved Copper
F-01 Dissolved Nickel
F-02 Dissolved Silver
F-03 Total Fluoride
K-01 pH
M-01
N-01
P-01
Ponded Water F
Note:
If a location-constituent pair does not have a plot, data was not available for that pair.
Page 2-2

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
3.0 MANN-KENDALL TREND TEST RESULTS
Results of the Mann-Kendall trend tests are displayed in Table 2. Trend analysis could
be performed for only 78 location-constituent pairs due to a lack of detect
measurements. Either there are less than four detects, or the number of non-detects is
greater than the number of detects. The average percentage of non-detects for all
constituent-location pairs included in the Mann-Kendall trend test is 55 percent. The
large number of non-detect measurements present in the dataset indicates that many
constituent-location pairs have concentrations less than the regulatory limit and are not
predicted to be of concern at Site.
Samples included in the Mann-Kendall trend tests were limited to 2016 and later to
represent the Site after implementation of ash basin closure and groundwater corrective
action activities. These activities will inherently alter the geochemistry and
groundwater flow of a Site. Data prior to ash basin closure and groundwater corrective
action activities could represent an entirely different set of trends based on the
geochemical system with source material present;thus, it is important to examine only
trends after implementation. Due to limited sampling post-ash basin closure and
groundwater corrective action activities, the amount of data that can be included in the
analysis is reduced.
Locations not displayed in Table 2 are excluded due to having less than minimum
number of samples required to run the "Kendall" package in RStudio. Locations must
have at least three samples to be included,but individual location-constituent pairs
with less than three measurements can be analyzed as long as the location itself has
three samples. However, it is important to note that location-constituent pairs with less
than four detects cannot be analyzed for trends based on the criteria in Section 1.0.
Out of the 78 constituent-location pairs that have trend conclusions, 84 percent are
stable with no trends (63 out of 78 constituent-location pairs), 15.4 percent have
statistically significant decreasing trends (12 out of 78 constituent-location pairs), and
3.8 percent have a statistically significant increasing trend (3 out of 78 constituent-
location pairs). The statistically significant increasing trends are present in total boron
for locations C-02 and 64E0-01, and total arsenic for location F-01.
As seen in Figure 2, total arsenic concentrations at F-01 are approximately 1 µg/L for all
but one sample. On November 7, 2019, total arsenic was measured to be 6.25 µg/L. The
next sample, taken on January 28, 2020, had a total arsenic concentration of 1.45 µg/L,
and the latest sample, taken on April 22, 2020,had a non-detect for total arsenic. This
Page 3-1

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
indicates that the measurement of 6.25 µg/L could be an outlier. The following
equations can be used as a test for outliers:
Max of Range = 75th percentile + 1.5(IQR)
Equation 1
Min of Range = 25th percentile — 1.5(IQR)
Equation 2
Notes:
Max of range= maximum value without being classified as an outlier
Min of range= maximum value without being classified as an outlier
75th Percentile= the 75`h percentile of data
25th Percentile ORP= the 25`h percentile of data
IQR= Interquartile Range
Using these equations on the total arsenic data at F-01, the calculated range is 0.195 µg/L
to 2.25 µg/L. Any measurement outside this range is considered an outlier, indicating
the 6.25 µg/L total arsenic concentration from November 7, 2019 is an outlier. If this
outlier is removed from the dataset and Mann-Kendall trend test is performed, the
resulting p-value is 0.1459, classified as stable with no trends. Thus, the removal of the
outlier would eliminate the increasing trend.
Overall, the results of the Mann-Kendall trend tests indicate a system that has been
geochemically stable after implementation of ash basin closure and groundwater
corrective action activities, with concentrations of constituents remaining stable or in
some cases decreasing over time. In three constituent-location pairs, there was an
increasing trend;however, when the identified outlier was removed from F-01, the
remaining data were found to be stable at that location.
Page 3-2

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
Separator Dike Total Chloride 3 0 3 0 No - - Cannot analyze for trends
64E0-01 Total Arsenic 4 4 0 100 No - - Cannot analyze for trends
64E0-02 Total Arsenic 4 4 0 100 No - - Cannot analyze for trends
82E0-02 Total Arsenic 3 3 0 100 No - - Cannot analyze for trends
A-01 Total Arsenic 12 12 0 100 No - - Cannot analyze for trends
B-01 Total Arsenic 13 13 0 100 No - - Cannot analyze for trends
C-01 Total Arsenic 13 7 6 54 No - - Cannot analyze for trends
C-02 Total Arsenic 7 4 3 57 No - - Cannot analyze for trends
D-01 Total Arsenic 7 7 0 100 No - - Cannot analyze for trends
E-01 Total Arsenic 10 9 1 90 No - - Cannot analyze for trends
F-01 Total Arsenic 12 6 6 50 Yes 0.0771 25 Statistically significant increasing trend
F-02 Total Arsenic 5 5 0 100 No - - Cannot analyze for trends
F-03 Total Arsenic 5 2 3 40 No - - Cannot analyze for trends
K-01 Total Arsenic 5 1 4 20 Yes 0.4624 - Stable, no significant trend
M-01 Total Arsenic 4 4 0 100 No - - Cannot analyze for trends
N-01 Total Arsenic 16 16 0 100 No - - Cannot analyze for trends
P-01 Total Arsenic 6 6 0 100 No - - Cannot analyze for trends
Ponded Water F Total Arsenic 6 1 5 17 Yes 0.4524 - Stable, no significant trend
Separator Dike Total Arsenic 3 3 0 100 No - - Cannot analyze for trends
64E0-01 Total Chromium (VI) 2 1 1 50 No - - Cannot analyze for trends
64E0-02 Total Chromium (VI) 2 2 0 100 No - - Cannot analyze for trends
82E0-02 Total Chromium (VI) 0 0 0 - No - - Cannot analyze for trends
A-01 Total Chromium (VI) 0 0 0 - No - - Cannot analyze for trends
B-01 Total Chromium (VI) 3 1 2 33 No - - Cannot analyze for trends
C-01 Total Chromium (VI) 3 3 0 100 No - - Cannot analyze for trends
C-02 Total Chromium (VI) 1 1 0 100 No - - Cannot analyze for trends
D-01 Total Chromium (VI) 1 0 1 0 No - - Cannot analyze for trends
E-01 Total Chromium (VI) 1 1 0 100 No - - Cannot analyze for trends
F-01 Total Chromium (VI) 1 1 0 100 No - - Cannot analyze for trends
F-02 Total Chromium (VI) 1 0 1 0 No - - Cannot analyze for trends
F-03 Total Chromium (VI) 2 0 2 0 No - - Cannot analyze for trends
K-01 Total Chromium (VI) 0 0 _ 0 - No - - Cannot analyze for trends
M-01 Total Chromium (VI) 1 0 1 0 No - - Cannot analyze for trends
N-01 Total Chromium (VI) 4 1 3 25 No - - Cannot analyze for trends
P-01 Total Chromium (VI) 1 0 1 0 No - - Cannot analyze for trends
Page 3-4

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress,LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
64E0-01 Total Boron 4 0 4 0 Yes 0.0894 6 Statistically significant increasing trend
64E0-02 Total Boron 4 0 4 0 Yes 0.3082 - Stable, no significant trend
82E0-02 Total Boron 3 0 3 0 No - - Cannot analyze for trends
A-01 Total Boron 12 0 12 0 Yes 0.0013 -48 Statistically significant decreasing trend
B-01 Total Boron 13 0 13 0 Yes 0.0019 -52 Statistically significant decreasing trend
C-01 Total Boron 13 0 13 0 Yes 0.2001 - Stable, no significant trend
C-02 Total Boron 7 0 7 0 Yes 0.0163 17 Statistically significant increasing trend
D-01 Total Boron 7 0 7 0 Yes 0.7639 - Stable, no significant trend
E-01 Total Boron 10 0 10 0 Yes 0.0024 -35 Statistically significant decreasing trend
F-01 Total Boron 12 0 12 0 Yes 0.0032 -44 Statistically significant decreasing trend
F-02 Total Boron 5 1 4 20 Yes 0.0864 -8 Statistically significant decreasing trend
F-03 Total Boron 5 _ 0 5 0 Yes 0.4624 - Stable, no significant trend
K-01 Total Boron 5 0 5 0 Yes 0.0864 -8 Statistically significant decreasing trend
M-01 Total Boron 4 0 4 0 Yes 0.7341 - Stable, no significant trend
N-01 Total Boron 16 11 5 69 No - - Cannot analyze for trends
P-01 Total Boron 6 5 1 83 No - - Cannot analyze for trends
Ponded Water F Total Boron 6 0 6 0 Yes 0.2597 - Stable, no significant trend
Separator Dike Total Boron 3 0 3 0 No - - Cannot analyze for trends
64E0-01 Total Chloride 4 0 4 0 Yes 1 - Stable, no significant trend
64E0-02 Total Chloride 4 0 4 0 Yes 0.1486 - Stable, no significant trend
82E0-02 Total Chloride 3 0 3 0 No - - Cannot analyze for trends
A-01 Total Chloride 12 0 12 0 Yes 0.0013 -48 Statistically significant decreasing trend
B-01 Total Chloride 13 0 13 0 Yes 0.00001 -72 Statistically significant decreasing trend
C-01 Total Chloride 13 0 13 0 Yes 0.1716 - Stable, no significant trend
C-02 Total Chloride 7 0 7 0 Yes 1 - Stable, no significant trend
D-01 Total Chloride 7 0 7 0 Yes 0.6486 - Stable, no significant trend
E-01 Total Chloride 10 0 10 0 Yes 0.2105 - Stable, no significant trend
F-01 Total Chloride 12 0 12 0 Yes 0.0016 -47 Statistically significant decreasing trend
F-02 Total Chloride 5 0 5 0 Yes 0.3122 - Stable, no significant trend
F-03 Total Chloride 5 0 5 0 Yes 0.2207 - Stable, no significant trend
K-01 Total Chloride 5 0 5 0 Yes 0.1296 - Stable, no significant trend
M-01 Total Chloride 4 0 4 0 Yes 1 - Stable, no significant trend
N-01 Total Chloride 16 0 16 0 Yes 0.4954 - Stable, no significant trend
P-01 Total Chloride 6 0 6 0 Yes 0.8483 - Stable, no significant trend
Ponded Water F Total Chloride 6 0 6 0 Yes 0.0085 -15 Statistically significant decreasing trend
Page 3-3

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
P-01 Total Mercury 6 0 6 0 Yes 0.2597 - Stable, no significant trend
Ponded Water F Total Mercury 5 1 4 20 Yes 0.2207 - Stable, no significant trend
Separator Dike Total Mercury 3 1 2 33 No - - Cannot analyze for trends
64E0-01 Total Selenium 4 1 3 25 No - - Cannot analyze for trends
64E0-02 Total Selenium 4 1 3 25 No - - Cannot analyze for trends
82E0-02 Total Selenium 3 1 2 33 No - - Cannot analyze for trends
A-01 Total Selenium 12 0 12 0 Yes 0.1692 - Stable, no significant trend
B-01 Total Selenium 13 11 2 85 No - - Cannot analyze for trends
C-01 Total Selenium 13 2 11 15 Yes 0.3201 - Stable, no significant trend
C-02 Total Selenium 7 1 6 14 Yes 0.1331 - Stable, no significant trend
D-01 Total Selenium 7 6 1 86 No - - Cannot analyze for trends
E-01 Total Selenium 10 8 2 80 No - - Cannot analyze for trends
F-01 Total Selenium 12 9 3 75 No - - Cannot analyze for trends
F-02 Total Selenium 5 5 0 100 No - - Cannot analyze for trends
F-03 Total Selenium 5 5 0 100 No - - Cannot analyze for trends
K-01 Total Selenium 5 4 1 80 No - - Cannot analyze for trends
M-01 Total Selenium 4 1 3 25 No - - Cannot analyze for trends
N-01 Total Selenium 16 16 _ 0 100 No - - Cannot analyze for trends
P-01 Total Selenium 6 4 2 67 No - - Cannot analyze for trends
Ponded Water F Total Selenium 6 0 6 0 Yes 0.1329 - Stable, no significant trend
Separator Dike Total Selenium 3 3 0 100 No - - Cannot analyze for trends
64E0-01 Dissolved Arsenic 2 2 0 100 No - - Cannot analyze for trends
64E0-02 Dissolved Arsenic 2 _ 2 0 100 No - - Cannot analyze for trends
82E0-02 Dissolved Arsenic 1 _ 1 0 100 No - - Cannot analyze for trends
A-01 Dissolved Arsenic 7 7 0 100 No - - Cannot analyze for trends
B-01 Dissolved Arsenic 9 9 0 100 No - - Cannot analyze for trends
C-01 Dissolved Arsenic 9 6 3 67 No - - Cannot analyze for trends
C-02 Dissolved Arsenic 2 1 1 50 _ No - - Cannot analyze for trends
D-01 Dissolved Arsenic 2 _ 2 0 100 No - - Cannot analyze for trends
E-01 Dissolved Arsenic 6 5 1 83 No _ - - Cannot analyze for trends
F-01 Dissolved Arsenic 8 3 5 38 Yes 0.4448 - Stable, no significant trend
F-02 Dissolved Arsenic 4 4 0 100 No - - Cannot analyze for trends
F-03 Dissolved Arsenic 3 1 2 33 No - - Cannot analyze for trends
K-01 Dissolved Arsenic 1 0 1 0 No - - Cannot analyze for trends
M-01 Dissolved Arsenic 2 y 2 0 100 No - - Cannot analyze for trends
Page 3-6

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
Ponded Water F Total Chromium (VI) 3 1 2 33 No - - Cannot analyze for trends
Separator Dike Total Chromium (VI) 0 0 0 No - - Cannot analyze for trends
64E0-01 Total Chromium 4 4 0 100 No - - Cannot analyze for trends
64E0-02 Total Chromium 4 4 0 100 No - - Cannot analyze for trends
82E0-02 Total Chromium 3 3 0 100 No - - Cannot analyze for trends
A-01 Total Chromium 12 10 2 83 No - - Cannot analyze for trends
B-01 Total Chromium 13 11 2 85 No - - Cannot analyze for trends
C-01 Total Chromium 13 12 1 92 No - - Cannot analyze for trends
C-02 Total Chromium 7 7 0 100 No - - Cannot analyze for trends
D-01 Total Chromium 7 7 0 100 No - - Cannot analyze for trends
E-01 Total Chromium 10 10 0 100 No - - Cannot analyze for trends
F-01 Total Chromium 12 10 2 83 No - - Cannot analyze for trends
F-02 Total Chromium 5 5 0 100 No - - Cannot analyze for trends
F-03 Total Chromium 5 5 0 100 No - - Cannot analyze for trends
K-01 Total Chromium 5 5 0 100 No - - Cannot analyze for trends
M-01 Total Chromium 4 3 1 75 No - - Cannot analyze for trends
N-01 Total Chromium 16 8 8 50 Yes 0.9614 - Stable, no significant trend
P-01 Total Chromium 6 6 0 100 No - - Cannot analyze for trends
Ponded Water F Total Chromium 6 4 2 67 No - - Cannot analyze for trends
Separator Dike Total Chromium 3 3 0 100 No - - Cannot analyze for trends
64E0-01 Total Mercury 2 0 2 0 No - - Cannot analyze for trends
64E0-02 Total Mercury 2 0 2 0 No - - Cannot analyze for trends
82E0-02 Total Mercury 3 0 3 0 No - - Cannot analyze for trends
A-01 Total Mercury 12 0 12 0 Yes 0.2437 - Stable, no significant trend
B-01 Total Mercury 12 0 12 0 Yes 0.2437 - Stable, no significant trend
C-01 Total Mercury 11 4 7 36 Yes 0.4238 - Stable, no significant trend
C-02 Total Mercury 7 3 4 43 Yes 0.8754 - Stable, no significant trend
D-01 Total Mercury 7 3 4 43 Yes 0.638 - Stable, no significant trend
E-01 Total Mercury 10 5 5 50 Yes 0.1786 - Stable, no significant trend
F-01 Total Mercury 12 1 11 8 Yes 0.3037 - Stable, no significant trend
F-02 Total Mercury 5 0 5 0 Yes 1 - Stable, no significant trend
F-03 Total Mercury 3 0 3 0 No - - Cannot analyze for trends
K-01 Total Mercury 5 0 5 0 Yes 1 - Stable, no significant trend
M-01 Total Mercury 4 0 4 0 Yes 0.7341 - Stable, no significant trend
N-01 Total Mercury 12 0 12 0 Yes 0.3037 - Stable, no significant trend
Page 3-5

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
M-01 Dissolved Cadmium 2 1 1 50 No - - Cannot analyze for trends
N-01 Dissolved Cadmium 9 0 9 0 Yes 0.1179 - Stable, no significant trend
P-01 Dissolved Cadmium 2 2 0 100 No - - Cannot analyze for trends
Ponded Water F Dissolved Cadmium 3 1 2 33 No - - Cannot analyze for trends
Separator Dike Dissolved Cadmium 1 1 0 100 No - - Cannot analyze for trends
64E0-01 Dissolved Chromium 2 2 0 100 No - - Cannot analyze for trends
64E0-02 Dissolved Chromium 2 2 0 100 No - - Cannot analyze for trends
82E0-02 Dissolved Chromium 1 1 0 100 No - - Cannot analyze for trends
A-01 Dissolved Chromium 7 7 0 100 No - - Cannot analyze for trends
B-01 Dissolved Chromium 9 8 1 89 No - - Cannot analyze for trends
C-01 Dissolved Chromium 9 9 0 100 No - - Cannot analyze for trends
C-02 Dissolved Chromium 2 2 0 100 No - - Cannot analyze for trends
D-01 Dissolved Chromium 2 2 0 100 No - - Cannot analyze for trends
E-01 Dissolved Chromium 6 6 0 100 No - - Cannot analyze for trends
F-01 Dissolved Chromium 8 8 0 100 No - - Cannot analyze for trends
F-02 Dissolved Chromium 4 4 0 100 No - - Cannot analyze for trends
F-03 Dissolved Chromium 3 3 0 100 No - - Cannot analyze for trends
K-01 Dissolved Chromium 1 1 0 100 No - - Cannot analyze for trends
M-01 Dissolved Chromium 2 1 1 50 No - - Cannot analyze for trends
N-01 Dissolved Chromium 11 11 0 100 No - - Cannot analyze for trends
P-01 Dissolved Chromium 2 2 0 100 No - - Cannot analyze for trends
Ponded Water F Dissolved Chromium 5 2 3 40 No - - Cannot analyze for trends
Separator Dike Dissolved Chromium 1 1 0 100 No - - Cannot analyze for trends
64E0-01 Dissolved Copper 2 2 0 100 No - - Cannot analyze for trends
64E0-02 Dissolved Copper 2 2 0 100 No - - Cannot analyze for trends
82E0-02 Dissolved Copper 1 1 0 100 No - - Cannot analyze for trends
A-01 Dissolved Copper 7 7 0 100 No - - Cannot analyze for trends
B-01 Dissolved Copper 9 9 0 100 No - - Cannot analyze for trends
C-01 Dissolved Copper 9 8 1 89 No - - Cannot analyze for trends
C-02 Dissolved Copper 2 1 1 50 No - - Cannot analyze for trends
D-01 Dissolved Copper 2 2 0 100 No - - Cannot analyze for trends
E-01 Dissolved Copper 6 4 2 67 No - - Cannot analyze for trends
F-01 Dissolved Copper 8 5 3 63 No - - Cannot analyze for trends
F-02 Dissolved Copper 4 3 1 75 No - - Cannot analyze for trends
F-03 Dissolved Copper 3 2 1 67 No - - Cannot analyze for trends
Page 3-8
L

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
N-01 Dissolved Arsenic 11 11 0 100 No - - Cannot analyze for trends
P-01 Dissolved Arsenic 2 2 0 100 No - - Cannot analyze for trends
Ponded Water F Dissolved Arsenic 5 0 5 0 Yes 1 - Stable, no significant trend
Separator Dike Dissolved Arsenic 1 1 0 100 No - - Cannot analyze for trends
64E0-01 Dissolved Beryllium 2 2 0 100 No - - Cannot analyze for trends
64E0-02 Dissolved Beryllium 2 2 0 100 No - - Cannot analyze for trends
82E0-02 Dissolved Beryllium 0 0 0 No - - Cannot analyze for trends
A-01 Dissolved Beryllium 0 0 0 No - - Cannot analyze for trends
B-01 Dissolved Beryllium 3 3 0 100 No - - Cannot analyze for trends
C-01 Dissolved Beryllium 3 3 0 100 No - - Cannot analyze for trends
C-02 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
D-01 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
E-01 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
F-01 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
F-02 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
F-03 Dissolved Beryllium 2 2 0 100 No - - Cannot analyze for trends
K-01 Dissolved Beryllium 0 0 0 No - - Cannot analyze for trends
M-01 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
N-01 Dissolved Beryllium 4 4 0 100 No - - Cannot analyze for trends
P-01 Dissolved Beryllium 1 1 0 100 No - - Cannot analyze for trends
Ponded Water F Dissolved Beryllium 3 3 0 100 No - - Cannot analyze for trends
Separator Dike Dissolved Beryllium 0 0 0 No - - Cannot analyze for trends
64E0-01 Dissolved Cadmium 0 0 0 No - - Cannot analyze for trends
64E0-02 Dissolved Cadmium 0 0 0 No - - Cannot analyze for trends
82E0-02 Dissolved Cadmium 1 1 0 100 No - - Cannot analyze for trends
A-01 Dissolved Cadmium 7 7 0 100 No - - Cannot analyze for trends
B-01 Dissolved Cadmium 7 6 1 86 No - - Cannot analyze for trends
C-01 Dissolved Cadmium 8 1 7 13 Yes 0.7105 - Stable, no significant trend
C-02 Dissolved Cadmium 2 0 2 0 No - - Cannot analyze for trends
D-01 Dissolved Cadmium 2 2 0 100 No - - Cannot analyze for trends
E-01 Dissolved Cadmium 6 4 2 67 No - - Cannot analyze for trends
F-01 Dissolved Cadmium 8 2 6 25 Yes 0.0809 -15 Statistically significant decreasing trend
F-02 Dissolved Cadmium 4 4 0 100 No - - Cannot analyze for trends
F-03 Dissolved Cadmium 1 1 0 100 No - - Cannot analyze for trends
K-01 Dissolved Cadmium 1 1 0 100 No - - Cannot analyze for trends
Page 3-7

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress,LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
F-03 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
K-01 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
M-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
N-01 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
P-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
Ponded Water F Dissolved Silver 2 2 0 100 No - - Cannot analyze for trends
Separator Dike Dissolved Silver 0 0 0 No - - Cannot analyze for trends
64E0-01 Total Fluoride 2 2 0 100 No - - Cannot analyze for trends
64E0-02 Total Fluoride 2 2 0 100 No - - Cannot analyze for trends
82E0-02 Total Fluoride 3 3 0 100 No - - Cannot analyze for trends
A-01 Total Fluoride 12 12 0 100 No - - Cannot analyze for trends
B-01 Total Fluoride 13 11 2 85 No - - Cannot analyze for trends
C-01 Total Fluoride 13 11 2 85 No - - Cannot analyze for trends
C-02 Total Fluoride 7 5 2 71 No - - Cannot analyze for trends
D-01 Total Fluoride 7 7 0 100 No - - Cannot analyze for trends
E-01 Total Fluoride 10 8 2 80 No - - Cannot analyze for trends
F-01 Total Fluoride 12 12 0 100 No - - Cannot analyze for trends
F-02 Total Fluoride 5 4 1 80 No - - Cannot analyze for trends
F-03 Total Fluoride 3 2 1 67 No - - Cannot analyze for trends
K-01 Total Fluoride 5 5 0 100 No - - Cannot analyze for trends
M-01 Total Fluoride 4 3 1 75 No - - Cannot analyze for trends
N-01 Total Fluoride 12 12 0 100 No - - Cannot analyze for trends
P-01 Total Fluoride 6 5 1 83 No - - Cannot analyze for trends
Ponded Water F Total Fluoride 6 3 3 50 No - - Cannot analyze for trends
Separator Dike Total Fluoride 3 1 2 33 No - - Cannot analyze for trends
64E0-01 pH 4 0 4 0 Yes 0.3082 - Stable, no significant trend
64E0-02 pH 4 0 4 0 Yes 0.7341 - Stable, no significant trend
82E0-02 pH 3 0 3 0 No - - Cannot analyze for trends
A-01 pH 12 0 12 0 Yes 1 - Stable, no significant trend
B-01 pH 13 0 13 0 Yes 0.4237 - Stable, no significant trend
C-01 pH 13 0 13 0 Yes 0.0026 -50 Statistically significant decreasing trend
C-02 pH 7 0 7 0 Yes 0.433 - Stable, no significant trend
D-01 pH 7 0 7 0 Yes 0.8754 - Stable, no significant trend
E-01 pH 10 0 10 0 Yes 0.6499 - Stable, no significant trend
F-01 pH 12 0 12 0 Yes 0.8363 - Stable, no significant trend
Page 3-10

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress, LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
K-01 Dissolved Copper 1 1 0 100 No - - Cannot analyze for trends
M-01 Dissolved Copper 2 1 1 50 No - - Cannot analyze for trends
N-01 Dissolved Copper 11 10 1 91 No - - Cannot analyze for trends
P-01 Dissolved Copper 2 1 1 50 No - - Cannot analyze for trends
Ponded Water F Dissolved Copper 5 1 4 20 Yes 0.4624 - Stable, no significant trend
Separator Dike Dissolved Copper 1 1 0 100 No - - Cannot analyze for trends
64E0-01 Dissolved Nickel 2 0 2 0 No - - Cannot analyze for trends
64E0-02 Dissolved Nickel 2 0 2 0 No - - Cannot analyze for trends
82E0-02 Dissolved Nickel 1 0 1 0 No - - Cannot analyze for trends
A-01 Dissolved Nickel 7 7 0 100 No - - Cannot analyze for trends
B-01 Dissolved Nickel 9 0 9 0 Yes 0.917 - Stable, no significant trend
C-01 Dissolved Nickel 9 0 9 0 Yes 1 - Stable, no significant trend
C-02 Dissolved Nickel 2 0 2 0 No - - Cannot analyze for trends
D-01 Dissolved Nickel 2 1 1 50 No - - Cannot analyze for trends
E-01 Dissolved Nickel 6 0 6 0 Yes 1 - Stable, no significant trend
F-01 Dissolved Nickel 8 0 8 0 Yes 0.5362 - Stable, no significant trend
F-02 Dissolved Nickel 4 3 1 75 No - - Cannot analyze for trends
F-03 Dissolved Nickel 3 0 3 0 No - - Cannot analyze for trends
K-01 Dissolved Nickel 1 0 1 0 No - - Cannot analyze for trends
M-01 Dissolved Nickel 2 0 2 0 No - - Cannot analyze for trends
N-01 Dissolved Nickel 11 7 4 64 No - - Cannot analyze for trends
P-01 Dissolved Nickel 2 1 1 50 No - - Cannot analyze for trends
Ponded Water F Dissolved Nickel 5 0 5 0 Yes 0.4624 - Stable, no significant trend
Separator Dike Dissolved Nickel 1 0 1 0 No - - Cannot analyze for trends
64E0-01 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
64E0-02 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
82E0-02 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
A-01 Dissolved Silver 0 0 0 No - - Cannot analyze for trends
B-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
C-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
C-02 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
D-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
E-01 Dissolved Silver 1 1 0 100 No - _ - Cannot analyze for trends
F-01 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
F-02 Dissolved Silver 1 1 0 100 No - - Cannot analyze for trends
Page 3-9

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant, Duke Energy Progress,LLC SynTerra
TABLE 2
RESULTS OF MANN-KENDALL TREND TEST (CONTINUED)
Percentage
Number of Non- Is Trend Analysis Two-Sided
Well ID Analyte Samples Detects Detects of Non- Applicable? P Value S Value Trend Conclusion
Detects
F-02 pH 5 0 5 0 Yes 0.8065 - Stable, no significant trend
F-03 pH 5 0 _ 5 0 Yes 0.8065 - Stable, no significant trend
K-01 pH 5 0 5 0 Yes 0.8065 - Stable, no significant trend
M-01 pH 4 0 4 0 Yes 0.7341 - Stable, no significant trend
N-01 pH 16 0 16 0 Yes 0.6507 - Stable, no significant trend
P-01 pH 6 0 6 0 Yes 0.1329 - Stable, no significant trend
Ponded Water F pH 6 _ 0 6 0 Yes 0.5661 - Stable, no significant trend
Separator Dike pH 3 0 3 0 No - - Cannot analyze for trends
Page 3-11

Mann-Kendall Trend Test Analysis August 2020
Asheville Steam Electric Plant,Duke Energy Progress,LLC SynTerra
FIGURES

64E0-01 64E0-02 64E0-03 82E0-01 82E0-02
441
-
6-
5-
4-
A-01 13-01 C-01 C-02 D-01
7-
"______•Nfr_e_._,A,\ 4e.A.---•-•-•..Ne--••••\fr, /I\---*--ikie,*-•-•\po
•- � ♦
6-
5-
4-
M
0
= E-01 F-01 F-02 F.03 K-01
o-
7-
6- •
•--....,..„---• 111-4r.\\\,,,_._...__________. ."--...............i\e______________.-A
-
d
- i L .. ........, ... ,.....
M-01 N-01 P-01 Ponded Water F Separator Dike
7 _ f •-- .
6-
5-
4-
f- co 0) 0 r-- co 0) o r- co 0) O r co 0) o r- co rn o
r- r- r- N r- r- N N r- r- N r N
O O O 0 O O 0 0 O 0 0 0 0 O O 0 O O O O
N N N N N N N N N N N N N N N N N N N N
Date
LEGEND NOTES ,� DUKE DRAWN BY: K.MARSAC DATE:07/15//2020
Stable, no trends Time vs pH plot for all locations with available data in 2016 or �� ENERGY REVISED BY: M.ROZIER FIGURE 1
-0- Non-detect later. Trends are denoted by the box color, if there is no color the TIME VERSUS pH
-D- Detect Statistically Significant Decreasing Trend data could not be analyzed for trends. PROGRESS CHECKED BY: S.GOAD
- Statistically Significant Increasing Trend MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends �r/� APPROVED BY: ASHEVILLE STEAM ELECTRIC PLANT
PROJECT MANAGER T.PLATING ARDEN, NORTH CAROLINA
synTerra
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-01 82E0-02
10-
3-
1 - 0—c0 0 o—co 0 o0 0 0 0 0
A-01 B-01 C-01 C-02 D-01
10-
I
3-
C)
Z 1 - • • • • • • ••• • • • • • • • 10 • • • • • • • • • • • • • • 0 IO 0 O O m 0
0
C
E-01 F-01 F-02 F-03 K-01
L
Q 10-
0
I-
3-
1 - 0 0 00 0 0---in?'-----.----- oe'A----"------.
_. ,
M-01 N-01 P-01 Ponded Water F Separator Dike
10-
3-
1 - 0 0 0 0 0 0 0 0 0 0 0
N co a) o r- co a) o r- co a) o N- co a) o r- co 0) 0
r- r- 01 N— r— r— N r- N— N --r— e— N .— t— r- N
O 0 0 0 0 O O 0 0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N N N N N N N N N
Date
LEGEND NOTES DRAWN BY: K.MARSAC DATE:07/15//2020
•� DUKEFIGURE 2
- Stable, no trends Time vs total arsenic concentration plot for all locations with V ENERGY REVISED BY: M. ROZIER TIME VERSUS TOTAL ARSENIC
-0- Non-detect available data in 2016 or later. Trends are denoted by the box
-0- Detect Statistically Significant Decreasing Trend color, if there is no color the data could not be analyzed for PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend trends. 0APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-02 A-01
5-
4-
3-
2-
1 - 00 00 00 0 o--oao-o-0-0
B-01 C-01 C-02 D-01 E-01
5-
4-
J 3-
z 2-
C> 1 _ 0 0
C
a)
N
Q F-01 F-02 F-03 K-01 M-01
y 5-
>
O 4
in
3-
G •
2-
Z1 - 0 00 0 0 0
r- co a> o
N
N-01 P-01 Ponded Water F Separator Dike o 0 0 0
NJ NI NI NI
-
4-
3-
2-
1 - 0000 0 000000 0 0 0
r I I I I I
r— co 0 o r— co cm o r— co 0 o r— CO Cr) o
N r- N- N r r N r r N
O O 0 0 0 0 O 0 0 0 0 0 O 0 0 0
N N N N N N N N N N N N N N N N
Date
LEGEND NOTES DRAWN BY K MARSAC DATE 07/15//2020
� DUKE FIGURE 3
Stable, no trends Time vs dissolved arsenic concentration plot for all locations with ENERGY REVISED BY: M.ROZIER TIME VERSUS DISSOLVED ARSENIC
—0— Non-detect available data in 2016 or later. Trends are denoted by the box
Statistically Significant Decreasing Trend PROGRESS CHECKED BY S.GOAD CONCENTRATION
Detect color, if there is no color the data could not be analyzed for
I - Statistically Significant Increasing Trend trends. 0APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 B-01 C-01
1.050
1.025-
1.000- 00 00 00 0-0 m-o
0.975-
0.950
C-02 D-01 E-01 F-01 F-02
1.050
0)
z
E 1.025-
LI
CD
1.000- o 0 0 0 0
m
> 0.975-
O
to
in
p 0.950
F-03 M-01 N-01 P-01 Ponded Water F
1.050
1.025-
1.000- 0-0 0 00- -0
o m o
0.975-
0.950 r
r- co rn o r- co rn o r- co a) o r- co rn o r- co 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N N N N N N N N N
Date
LEGEND NOTES etas DUKE DRAWN BY: K.MARSAC DATE:07/15//2020 FIGURE 4
Stable, no trends Time vs dissolved beryllium concentration plot for all locations ENERGY REVISED BY M. ROZIER TIME VERSUS DISSOLVED BERYLLIUM
--0- Non-detect with available data in 2016 or later.There are not enough
f Detect Statistically Significant Decreasing Trend dissolved beryllium measurements to discern trends for any PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend location.
No Color- Cannot Analyze for Trends 0 APPROVED BY: MANN KENDALL ANALYSIS
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterraco rp.corn

82E0-02 A-01 B-01 C-01 C-02
1.0-
0.3- . \/\/
0 1 - o o-o00--0-0 0
D-01 E-01 F-01 F-02 F-03
1 0-
7-3 J
0.3-
Z
E 0 1 - O O O O O O o
3
E
ea K-01 M-01 N-01 P-01 Ponded Water F
U
a)
> 1.0 ....--------__________....4\re
-
O
Uf
N 0.3-
0.1 - 0 0 0
N- co O) o N- co O) o P- CO O) o N- co O) o
r e- N r r r N r r r N r r r N
Separator Dike o 0 0 0 0 0 0 0 0 CD 0 00 0 CD CD
N N N N N N N N N N N N N N N N
1.0-
0.3-
01 - o
, r , ,
N- co o) o
r N
o O o o
N N N N
Date
LEGEND NOTES ir' DUKE DRAWN BY: K.MARSAC DATE:07/15//2020 FIGURE 5
Stable, no trends Time vs dissolved cadmium concentration plot for all locations ENERGY REVISED BY: M.ROZIER TIME VERSUS DISSOLVED CADMIUM
-0- Non detect with available data in 2016 or later. Trends are denoted by the
-IVDetect Statistically Significant Decreasing Trend box color, if there is no color the data could not be analyzed for PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend trends. APPROVED BY MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends 0
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
syt1Terra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-01 82E0-02
1000
Ef
100 —• `—e•-- —•
10. • •- -• .
A-01 B-01 C-01 C-02 D-01
1000
100 sk...„,...„.,* ...._4_,,,..........„."..vo ...___i_40......-46-----____. ir„..•--_,._•.—s______________.E 10
cu
_o E-01 F-01 F-02 F-03 K-01
.c 1000
U
2
I- 100'
.� • • .•-_______•
10. .-----.-AkNVAA\A..
M-01 N-01 P-01 Ponded Water F Separator Dike
1000.
100
10 '
t` co 0 0 i.' i'i
r— co a) o r co a) o r` coo a) o
, N e— ,— e N ,— e--O O O O O O O O O O O O N N N N N N N N N N N N
Date
LEGEND NOTES DRAWN BY: K.MARSAC DATE:07/15//2020
' DUKEFIGURE 6
- Stable, no trends Time vs total chloride concentration plot for all locations with ENERGY REVISED BY: M.ROZIER TIME VERSUS TOTAL CHLORIDE
Non-detect available data in 2016 or later. Trends are denoted by the box
f Detect Statistically Significant Decreasing Trend color, if there is no color the data could not be analyzed for PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend trends. APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends 0
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-02 A-01
1.25-
1.00- co 0o 00 0 o-oao-o-o-o
0.75-
0.50-
0.25-
0.00-
B-01 C-01 C-02 D-01 E-01
1.25
1.00- • • • • • • • • 0 0 0 0 0 0 0 000
J 0.75-
z 0.50-
v
E 0.25-
E 0.00-
O
t F-01 F-02 F-03 K-01 M-01
U 1.25
MI
CD> 1.00- 0 0 0 0 00 0 0
N 0.75-
In
C 0 50-
0.25-
0.00-
r-- co rn o
r- ,— N
N-01 P-01 Ponded Water F Separator Dike o 0 0 0
1.25J CV N N N
1.00- 0000 0 000 000 0 0 0
0.75-
0.50-
0.25-
0.00-
i I I , I , I I I I I I I , I
r` CO a) C r CO 0) O r` Co CS) C N Co 0) C
r— r— N r— r— N r- N N
O O O 0 0 0 O 0 0 0 0 0 0 O 0 0
N N N N N N (N N N N N N N N N N
Date
LEGEND NOTES (� DUKE DRAWN BY: K.MARSAC DATE 07/15//2020 FIGURE 7
Stable, no trends Time vs dissolved chromium concentration plot for all locations ENERGY REVISED BY: M. ROZIER TIME VERSUS DISSOLVED CHROMIUM
—0— Non-detect with available data in 2016 or later. There are not enough
—IV Detect - Statistically Significant Decreasing Trend °R^ RFS� CHECKED BY S.GOAD CONCENTRATION
dissolved chromium measurements to discern trends for any
- Statistically Significant Increasing Trend location.
No Color- Cannot Analyze for Trends 0APPROVED BY MANN KENDALL ANALYSIS
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-01 82E0-02
2.5-
2.0-
1.5-
1.0- o-00 0 0 co 0 co 0 0 o c
0.5-
A-01 B-01 C-01 C-02 D-01
2.5-
2.0-
•� 1.5-
07 1.0-' • • • • • • • • • • • O O 0 0 0 O O O 0 0 0 G
Z
r.r
E 0.5-
0
0 E-01 F-01 F-02 F-03 K-01
L
C.) 2.5-
cz 2.0-
0
H 1.5-
1,0- 0 O O 0 0 0 000 • • • • • ••• • • 0 0 0 0 0 0 00 0 0 0 0 0 0 0
0.5-
M-01 N-01 P-01 Ponded Water F Separator Dike
2.5-
2.0-
1.5-
1.0- o 0 o m o -.qp o -
0.5-
I . . I I r I I I i I I
N. CO 0) 0 N - CO O 0 N— CO 0) 0 N— Co o) 0 N— co 0) O
r- r- r- N r- r- r- CV N— r- r- N r- ,— r- N r- c— N
0 0 0 0 0 O 0 0 0 O 0 0 0 0 0 0 0 O O 0
N N N N N N N N N N N N N N N N N N N N
Date
LEGEND NOTES t' DUKE DRAWN BY K MARSAC DATE 07/15//2020 FIGURE 8
Stable, no trends Time vs total chromium concentration plot for all locations with ENERGY REVISED BY: M. ROZIER TIME VERSUS TOTAL CHROMIUM
-0- Non-detect available data in 2016 or later. Trends are denoted by the box
f Detect Statistically Significant Decreasing Trend color, if there is no color the data could not be analyzed for PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend trends. 0APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
Syn1Terra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 B-01 C-01
0.8-
0.6-
0.4-
02 -
iI I
0.0- I �o
z C-02 D-01 E-01 F-01 F-02
0.8- •
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t-
t
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.1., 0.4-
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a)
to
> 0.2
03
d
I 0.0 0 • 0 0
iv —
r
C F-03 M-01 N-01 P-01 Ponded Water F
I— —
0.8-
0.6-
0.4- •
0.2-
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• I I I I 1 1
f--- co o) O t` co a) O N- co O) O r` co a) O N- co a) O
t— c- N r t— (N ,— CV s— N ,— r N
O O O O O O O O O 0 O 0 O O O O O O O O
N N N N N N N N N N N N N N N N N N N N
Date
LEGEND. NOTES (, DUKE DRAWN BY K.MARSAC DATE:07/15N2020 FIGURE 9
Time vs total hexavalent chromium concentrationplot for all ENERGY TIME VERSUS TOTAL HEXAVALENT
-0- Non detect - Stable, no trends REVISED BY: M ROZIER
locations with available data in 2016 or later. There are not
+ Detect Statistically Significant Decreasing Trend enough total hexavalent chromium measurements to discern PROGRESS CHECKED BY. S.GOAD CHROMIUM CONCENTRATION
- Statistically Significant Increasing Trend trends for any location. 0APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com

64E0-01 64E0-02 64E0-03 82E0-02 A-01
30.0-
10.0 I
-
3.0-
1.0- 03 00 0 o-oao-ao-o
0.3-
B-01 C-01 C-02 D-01 E-01
30.0-
10.0-
J
3.0-
•A
... 1.0' o o
s-
a)
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0
U F-01 F-02 F-03 K-01 M-01
> 30.0-
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w
CI
3.0-
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0.3- , ,
r-- co rn o
N-01 P-01 Ponded Water F Separator Dike (o" o N0 0
N
30.0-
10.0-
3.0-
1.0- 4‘300 0 000 000 • 0 0
0.3- , , , , , , , , I , , ,
r- Co coo r- co 0 0 N- co rn o r` co rn o
(V e- e- e- N e- r- e- (N e- e- e- NO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N N N N N
Date
LEGEND NOTES ,�' DUKE DRAWN BY, K.MARSAC DATE:0 7/1 5/12 0 2 0 FIGURE 10
- Stable, no trends Time vs dissolved copper concentration plot for all locations with ENERGY REVISED BY: M.ROZIER TIME VERSUS DISSOLVED COPPER
-0- Non-detect available data in 2016 or later. Trends are denoted by the box
f Detect Statistically Significant Decreasing Trend color, if there is no color the data could not be analyzed for PROGRESS CHECKED BY: S.GOAD CONCENTRATION
- Statistically Significant Increasing Trend trends. APPROVED BY: MANN KENDALL ANALYSIS
No Color- Cannot Analyze for Trends 0
PROJECT MANAGER: T.PLATING ASHEVILLE STEAM ELECTRIC PLANT
synTerra ARDEN, NORTH CAROLINA
www.synterracorp.com