NC0005088_CSS_Appendix A_20191231

Corrective Action Plan Update December 2019
Cliffside Steam Station SynTerra
FI UU► 9 . 1,
REGULATORY CORRESPONDENCE
Notice of Regulatory Requirements (August 13, 2014)
Background Soil and Groundwater Dataset Review (July 7, 2017)
Approval of Provisional Background Threshold Values (October 11, 2017)
Approval of Provisional Background Threshold Values - Attachments
(October 11, 2017)
Corrective Action Plan Content for Duke Energy Coal Ash Facilities (April 27,
2018)
Approval of Revised Background Threshold Values (May 14, 2018)
Approval of Revised Background Threshold Values - Attachments (May 14,
2018)
2018 Comprehensive Site Assessment Update Comments (June 29, 2018)
Specific Comments (28 Pages in Total) Pertinent to Individual Source Areas
and to the Report Titled 'Cliffside CSA Update' (July 17, 2018)
Final Classification of the Three Coal Combustion Residuals Surface
Impoundments located at Duke Energy's James E. Rogers Energy
Complex (formerly Cliffside Steam Station), Rutherford and Cleveland
County, NC, Pursuant to N.C. Gen. Stat.§ 130A-309.213(d)(1).
(November 13, 2018)
DEQ Coal Combustion Residuals Surface Impoundment Closure
Determination, Rogers Energy Complex/Cliffside Steam Station (April
1, 2019)
Response to the Optimized Interim Monitoring Plan (IMP) for 14 Duke
Energy Facilities - Modification Request Annual Reports - Modification
Request (April 4, 2019)
Final Comprehensive Site Assessment and Corrective Action Plan Approvals
for Duke Energy Coal Ash Facilities (April 5, 2019)
Revised Background Threshold Values for Soil (May 23, 2019)
Duke Energy Interpretation of Corrective Action Plan Content Guidance
(January 23, 2019) - North Carolina Department Environmental
Quality Response and Conditional Approval (September 10, 2019)
Approach to Managing Constituents of Interest for Purposes of Corrective
Action Plans (October 24, 2019)

A 4
A=(WA
4AF1
NCDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory John E. Skvarla, III
Governor Secretary
August 13, 2014
CERTIFIED MAIL 7004 2510 0000 3651 1168
RETURN RECEIPT REQUESTED
Paul Newton
Duke Energy
526 South Church Street
Charlotte, NC 28202
Subject: Notice of Regulatory Requirements
Title 15A North Carolina Administrative Code (NCAC) 02L .0106
14 Coal Ash Facilities in North Carolina
Dear Mr. Newton:
Chapter 143, North Carolina General Statutes, authorizes and directs the Environmental
Management Commission of the Department of Environment and Natural Resources to protect
and preserve the water and air resources of the State. The Division of Water Resources (DWR)
has the delegated authority to enforce adopted pollution control rules.
Rule 15A NCAC 02L .0103(d) states that no person shall conduct or cause to be conducted any
activity which causes the concentration of any substance to exceed that specified in 15A NCAC
02L .0202. As of the date of this letter, exceedances of the groundwater quality standards at 15A
NCAC 02L .0200 Classifications and Water Quality Standards Applicable to the Groundwaters
of North Carolina have been reported at each of the subject coal ash facilities owned and
operated by Duke Energy (herein referred to as Duke).
Groundwater Assessment Plans
No later than September, 26 2014 Duke Energy shall submit to the Division of Water Resources
plans establishing proposed site assessment activities and schedules for the implementation,
completion, and submission of a comprehensive site assessment (CSA) report for each of the
following facilities in accordance with 15A NCAC 02L .0106(g):
Asheville Steam Electric Generating Plant
Belews Creek Steam Station
Buck Steam Station
Cape Fear Steam Electric Generating Plant
Cliffside Steam Station
1636 Mail Service Center, Raleigh, North Carolina 27699-1636
Phone: [phone] Internet: www.ncdenr.gov
An Equal Opportunity 1 Affirmative Action Employer— Made in part by recycled paper

Mr. Paul Newton
August 12, 2014
Page 2 of 3
Dan River Combined Cycle Station
H.F. Lee Steam Electric Plant
Marshall Steam Station
Mayo Steam Electric Generating Plant
Plant Allen Steam Station
Riverbend Steam Station
Roxboro Steam Electric Generating Plant
L.V. Sutton Electric Plant
Weatherspoon Steam Electric Plant
The site assessment plans shall include a description of the activities proposed to be completed
by Duke that are necessary to meet the requirements of 15A NCAC 02L .0106(g) and to provide
information concerning the following:
(1) the source and cause of contamination;
(2) any imminent hazards to public health and safety and actions taken to mitigate
them in accordance to 15A NCAC 02L .0106(f);
(3) all receptors, and significant exposure pathways;
(4) the horizontal and vertical extent of soil and groundwater contamination and all
significant factors affecting contaminant transport; and
(5) geological and hydrogeological features influencing the movement,. chemical, and
physical character of the contaminants.
For your convenience, we have attached guidelines detailing the information necessary for the
preparation of a CSA report. The DWR will review the plans and provide Duke with review
comments, either approving the plans or noting any deficiencies to be corrected, and a date by
which a corrected plan is to be submitted for further review and comment or approval. For those
facilities for which Duke has already submitted groundwater assessment plans, please update
your submittals to ensure they meet the requirements stated in this letter and referenced
attachments and submit them with the others.
Receptor Survey
No later than October 14t', 2104 as authorized pursuant to 15A NCAC 02L .0106(g), the DWR is
requesting that Duke perform a receptor survey at each of the subject facilities and submitted to
the DWR. The receptor survey is required by 15A NCAC 02L .0106(g) and shall include
identification of all receptors within a radius of 2,640 feet (one-half mile) from the established
compliance boundary identified in the respective National Pollutant Discharge Elimination
System (NPDES) permits. Receptors shall include, but shall not be limited to, public and private
water supply wells (including irrigation wells and unused or abandoned wells) and surface water
features within one-half mile of the facility compliance boundary. For those facilities for which
Duke has already submitted a receptor survey, please update your submittals to ensure they meet
the requirements stated in this letter and referenced attachments and submit them with the others.
If they do not meet these requirements, you must modify and resubmit the plans.

Mr. Paul Newton
August 12, 2014
Page 3 of 3
The results of the receptor survey shall be presented on a sufficiently scaled map. The map shall
show the coal ash facility location, the facility property boundary, the waste and compliance
boundaries, and all monitoring wells listed in the respective NPDES permits. Any identified
water supply wells shall be located on the map and shall have the well owner's name and
location address listed on a separate table that can be matched to its location on the map.
Failure to comply with the State's rules in the manner and time specified may result in the
assessment of civil penalties and/or the use of other enforcement mechanisms available to the
State.
We appreciate your attention and prompt response in this matter. If you have any questions,
please feel free to contact S. Jay Zimmerman, Water Quality Regional Operations Section Chief,
at [phone].
2hn
ierely,
E. Skvarla, III
Attachment enclosed
cc: Thomas A. Reeder, Director, Division of Water Resources
Regional Offices — WQROS
File Copy

Water Resources
Environmental Quality
July 7, 2017
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. JAY ZIMMERMAN
Director
Subject: Duke Energy Submittal - Background Soil and Groundwater Statistical Methodology for
14 Duke Energy Facilities a -mails submitted May 26, 2017
Dear Mr. Draovitch:
The North Carolina Department of Environmental Quality (DEQ) has received and reviewed the May 26,
2017 a -mails from Duke Energy providing background soil and groundwater datasets. These site -specific
data were compiled following direction provided in an April 28, 2017 letter from DEQ to address technical
concerns related to site assessment and corrective action along with revisions to the Statistical Methods for
Developing Reference Background Concentrations for Groundwater and Soil at Coal Ash Facilities (HDR
Engineering, Inc. and Synterra Corporation, January 2017) technical memorandum (TM).
Attached are reviews of the soil and groundwater datasets for each Duke Energy coal ash facility. These
reviews identify data that are appropriate for inclusion in the statistical analysis to determine background
threshold values for both media following the methodology outlined in the TM. Additional requirements
related to soil and groundwater background determinations are specified for each facility. With approval
of these background datasets, preliminary background determinations for each media are expected to be
completed and provided within 30 days of receipt of this letter for those facilities that will submit
Comprehensive Site Assessments (CSAs) by October 31, 2017. For all other facilities that will submit
CSAs later, preliminary background determinations for each media are due within 60 days of receipt of this
letter.
If you have any questions, please feel free to contact Steve Lanter at [phone].
Sincerely,
S. Jayinlerman, P.G., Director
Division of Water Resources
Attachments: DEQ Background Dataset Reviews for the 14 coal ash facilities
cc: WQROS Regional Offices
WQROS Central File Copy
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional Operations Section
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

Allen Steam Station
Groundwater
• The following background wells are appropriate for use:
o BG-lS, BG-2S/D, BG-4S/DBR, GWA-19S, GWA-21SBR, GWA-23S, and
GWA-26S/D
• The following background wells are NOT appropriate for use:
o BG-lD — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
o BG-2BR — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included. (Note: while there does
appear to be a topographic divide additional evaluation is needed to determine if
this is just a shallow divide or if it is indeed a divide for all flow layers.)
o AB-4S/DBR — Groundwater elevations below the nearest pond elevation has been
observed in several sampling events since installation of AB-4S/D. Due to the
potential for groundwater flow from the basin toward/through the well cluster this
location should NOT be considered a background location. AB-4BR should also
NOT be considered a background location (potential vertical migration from the
unconsolidated zone). (Note: Duke will evaluate further regarding pond elevation
utilized for assessment.)
o GWA-21D —Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
• All identified sample event dates are appropriate for use.
• The dataset for the shallow flow layer meets the minimum requirement of 10 samples after
excluding samples.
• The dataset for the deep flow layer does NOT meet the minimum requirement of 10
samples after excluding samples. Additional samples are require .
• The dataset for the bedrock flow layer does NOT meet the minimum requirement of 10
samples after excluding samples. Only 4 valid samples, but when additional evaluation
regarding nearest pond elevation used for the AB-4S/DBR locations is provided additional
samples may be available for inclusion.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o BG-lD (1.0-2.0), BG-lD (9.0-10.5), BG-1D (19.0-20.5), BG-lD (45-50), BG-2D
(1.0-2.5), BG-2D (8.5-10.0), BG-2D (18.0-20.0), BG-3D (1-2.5), BG-3D (13.5-
15), BG-3D (18.5-20), GWA-14D (10.0-12.0), GWA-8D (38.5-40), and GWA-8D
(48.5-50)
• The following background samples are NOT appropriate for use:
o GWA-15D —Sample is at or immediately adjacent to the waste boundary west of
the ash storage area and was also collected in fill material (according to boring log).
Allen Steam Station Pagel of 2

o GWA-5D —Sample is at or immediately adjacent to the waste boundary east of the
ash basin (immediately downgradient) and was also collected in fill material
(according to the boring log).
• The dataset meets minimum requirement of 10 samples after excluding samples.
• The reporting limits for Antimony and Thallium were above the IHSB PSRG Protection of
Groundwater values. Therefore, the number of useable values in the background dataset
is severely limited for these constituents. Additional samples analyzed at a lower detection
limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Allen Steam Station Page 2 of 2

Asheville Steam Electric Plant
Groundwater
• All identified background wells are appropriate for use.
o MW-101 CB-01, CB-09, CB-09SL, NM-24S, CB-011), AMW-03B, and CB-09BR
o Duke Energy recommended adding wells GW-I, GW-1D, and GW-1BR to the
background dataset. Based on a review of the information provided, these wells
may be added to the background dataset. If these wells are added, the new raw
background dataset should be re -submitted to DWR.
• The datasets for each flow layer meets the minimum requirement of at least 10 samples.
• All identified sample event dates are appropriate for use.
• All identified outliers are acceptable and should be removed from the background dataset.
o If GW-1, GW-ID, and GW-1BR are added to the background dataset then re -test
the new dataset for outliers and re -submit to the DWR, including strikethroughs of
outliers and other unusable data (e.g high pH, high turbidity, autocorrelated data.
Soil
• The following background samples are appropriate for use:
o CB-01 SB (7-8), CB-01 SB (30-31), CB-09 SB (1-2), CB-09 SB (25-27), GW-01
SB (1-2), MW-11SB (1.5-2), MW-12 SB (1.5-2), MW-13SB (1.5-2), MW-13SB
(14.5-15), MW-14SB (1.5-2), MW-22 (1-2), MW-23BR (2-3), and NM-24SB (1-
2)
• The following background samples are NOT appropriate for use:
o MW-08 and MW-09 — Samples are at or immediately adjacent to the waste
boundary and should not be used as background locations, even though the samples
were collected above the seasonal high water table.
o CB-08, MW-03, MW-05, and MW-07 — Downgradient of site contamination.
o MW-13SB (22-22.5) — Sample was collected 3-feet below the water table and
should not be used.
• The dataset meets the minimum requirement of at least 10 samples after excluding samples.
• The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the
background dataset is severely limited for these constituents. Additional samples analyzed
at a lower detection limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Asheville Steam Electric Plant Page 1 of 1

Belews Creek Steam Station
Groundwater
• All identified background wells are appropriate for use:
o BG-2S, BG-3S, MW-202S, MW-3, BG-1D, BG-2D, BG-3D, BG-202D, BG-2BR-
A, and MW-202BR
• The datasets for the shallow and deep flow layers meet the minimum requirement of 10
samples.
• The dataset for the bedrock flow layer does NOT meet the minimum requirement of 10
samples. Additional samples are required.
• All identified sample event dates are appropriate for use.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• All identified background samples are appropriate for use:
o BG-1D (1-2), BG-1D (11), BG-1D (21), BG-lD (31), BG-2D (1-2), BG-2D (10-
12), BG-2D (20-22), BG-2D (30-32), BG-3S (1-2), BG-3S (10-12), BG-3S (20-
22), GWA-3D (34-35.5), GWA 4S (45-47), GWA-12D (10-12), GWA-12D (15-
17), GWA-12D (20-22), and GWA-12D (25-27)
• The dataset meets the minimum requirement of 10 samples.
• The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the
background dataset is severely limited for these constituents. Additional samples analyzed
at a lower detection limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Belews Creek Steam Station Page 1 of 1

Buck Combined Cycle Station
Groundwater
• The following background wells are appropriate for use.
o BG-18, BG-2S/D, BG-3SBRU, NM-6S/D, GWA-lS, MW-613R, and MW-8S/D
• The following background wells are NOT appropriate for use:
o BG-1D/BR— Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
o BG-2BR — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
o MW-8BR — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
• All identified sample event dates are appropriate for use.
• The datasets for each flow layer meets the minimum requirement of 10 samples after excluding
samples.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
The following background samples are appropriate for use:
o BG-lD (1-2), BG-1D (9.8-11.2), BG-1D (16.4-17.9), BG-2D (2), BG-2D (10-11.5),
BG-2D (13.5-15), BG-3BRU (1-2), BG-3BRU (10-10.5), BG-3BRU (20-20.5), GWA-
lOD (3.0), and GWA-11D (19-20.5)
The following background samples are NOT appropriate for use:
o GWA-11) — Sample was collected from 0.3-0.6 ft. bgs. Per IHSB Guidance, these
samples were taken too shallow.
o GWA-6BRU — Sample is located downgradient of the Cells 2 and 3 and within 1 foot
of the water table.
o GWA-7D — Sample is located downgradient of the Cells 2 and 3 and within 1 foot of
the water table.
o GWA-91) — Sample is located downgradient of Cell 1, both sample intervals were
collected in fill material (according to boring log) and one sample interval was
collected within 1 foot of the water table.
o GWA-12S —Sample is located downgradient of the ash basin.
o GWA-22D — Sample is located downgradient of Cell 1 and sample interval was
collected in fill material (according to boring log).
• The dataset meets minimum requirement of 10 samples after excluding samples.
• The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the background
dataset is severely limited for these constituents. Additional samples analyzed at a lower
detection limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing fill
should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Buck Combined Cycle Station Page 1 of 1

Cane Fear Steam Electric Plant
Groundwater
• All identified background wells are appropriate for use:
o MW-15SU, MW-15SL, MW-16S, MW-09, MW-9BR, MW-15BR, and MW-16BR
• The datasets for all flow layers meet the minimum requirement of 10 samples.
• The following sample event dates are NOT appropriate for use:
o MW-15BR
■ 3/2/16 — Less than 60 days from previous sample.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o BG-01(Geosyntec)(2.0-2.5), BG-02(Geosyntec)(2.0-2.5), BG-03(Geosyntec)(2.0-
2.5), MW-09 SB(2-3), MW-09 SB (6-7), and MW-22 SB (3-4)
• The following background samples are NOT appropriate for use:
o MW-05BR SB(0-2), MW-09 SB(0-2), MW-l0BR SB(0-2), MW-12BR SB(0-2),
MW-15 SB(0-2), MW-20 SB(0-2), MW-22 SB(0-2), and MW-23 SB(0-2) — Per
IHSB Guidance, these samples were taken too shallow.
o BG-04(Geosyntec)(2.0-2.5) and BG-05(Geosyntec)(2.0-2.5) — Samples taken
down -gradient of 1985 Ash Pond.
• The dataset does NOT meet the minimum requirement of 10 samples. Additional samples
are required.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Cape Fear Steam Electric Plant Page 1 of I

James E. Rogers Energy Complex
Groundwater
• All identified background wells are appropriate for use.
o BG-1S, CCPMW-1S, MW-305, MW-325, GWA-245, GWA-255, GWA-30S, BG-
1D, MW-24D, MW-32D, GWA-24D, MW-32BR, CCPMW-ID, MW-24DR,
GWA-24BR, GWA-30BR, MW-22BR, and MW-22DR
• The datasets for all flow layers meet the minimum requirement of 10 samples.
• All identified sample event dates are appropriate for use.
• The following outliers are NOT appropriate for use and should be removed from the
background dataset:
Soil
o Total Dissolved Solids — 10,700,000 ug/L (saprolite)
o Total Dissolved Solids — 4,410,000 ug/L (saprolite)
o Total Dissolved Solids—407,000 ug/L (transition zone)
o Total Dissolved Solids—116,000 ug/L (transition zone)
o Iron — 31200 ug/L (transition zone)
o Vanadium — 3 ug/L (transition zone)
The following background samples are appropriate for use:
o BG-ID (3.5-5), BG-ID (8.5-10), BG-2D (3.5-5), BG-2D (8.5-10), BG-2D (18.5-
20), BG-2D (28.5-30), MW-30D (3.5-5.5), MW-30D (8.5-10), MW-30D (18.5-20),
MW-30D (28.5-30), MW-32D (3.5-5), MW-32D (8.5-10), MW-32D (18.5-20),
MW-32S (22.5-24), MW-42D (28.5-30), and GWA-25D (8.5-10)
The following background samples are NOT appropriate for use:
o BG-lS (3.5-5), BG-IS (8.5-10), MW-30S (4-5), MW-30S (9-10), MW-30S (19-
20), and MW-30S (28-29), — Only analyzed for TOC.
o GWA-1 OD — Located at or immediately adjacent to the waste boundary at Units 1-
4 basin.
o GWA-31D (7), GWA-31D (8.7), and GWA-31BR — Located at or immediately
adjacent to and downgradient of the waste boundary at Unit 5 basin and are adjacent
to a road and parking lot.
o MW-38D (33.5-35) — This location is downgradient of the Unit 5 Inactive Ash
Basin and adjacent to the Broad River.
o GWA-3D (48.5-50) — Location is downgradient of the Unit 5 Inactive Ash Basin.
o GWA-12BRU (20-23.5) — Location is immediately downgradient of Units 1-4
Inactive Ash Basin. May be close to water table and is near the Broad River.
o GWA-21BRU (5) — This sample may be immediately above the water table and
more importantly, the location is potentially downgradient of a basin and is situated
adjacent to the Broad River where there a potentially significant fluctuations of
water levels by a discharge point.
o GWA-22S (3-5) — Location is side gradient of the Active Ash Basin and adjacent
to the Broad River. The sample was collected within the screen interval of the well.
James E. Rogers Energy Complex Page 1 of 2

o GWA-27D (13.5-15) and GWA-27D (24.9) — Location is adjacent to and
downgradient of the impoundment. The sample was collected within the screened
interval of the well.
o NM-40BRU (3.5-5) — Location is adjacent to and downgradient of the Unit 5
Inactive Ash Basin and near the Broad River, and the sample was collected from
within the screened interval.
o GWA-61) (28.5-30) — Location is immediately downgradient of Unit 5 Inactive Ash
Basin and may be close to water table and is near the Broad River.
• The dataset meets the minimum requirement of 10 samples after excluding samples.
• The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the
background dataset is severely limited for these constituents. Additional samples for these
three parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• The following outlier is NOT appropriate for use and should be removed from the
background dataset:
o MW-32S (22.5-24)
■ Arsenic — 7.9 mg/kg
James E. Rogers Energy Complex Page 2 of 2

Dan River Combined Cycle Station
Groundwater
• The following background wells are appropriate for use:
o GWA-9S, BG-11), GWA-9D, MW-231), MW-23BR, BG-5S, BG-51), BG-IOS,
BG-101), and BG-10BR
o GWA-9S/D and BG-IOS/D/BR appear to be appropriate for use; however, further
evaluation will be needed to determine whether these wells are truly located up -
gradient of the ash storages.
• The following background wells are NOT appropriate for use:
o GWA-12S/D —It appears that coal ash constituent boron, have been detected in soil
samples taken from this well.
o MW-20S/D — This well could be impacted by groundwater flowing from the
storage 1 area.
• The datasets for the shallow and deep flow layers meet the minimum requirement of 10
samples after excluding samples.
• The dataset for the bedrock flow layer does NOT meet the minimum requirement of 10
samples. Additional samples are required.
• All identified sample event dates are appropriate for use.
o Provisional background threshold value for hexavalent chromium (shallow flow
layer), vanadium (shallow flow layer), and radionuclides (shallow flow layer) are
based on a limited dataset. Additional samples are required.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
The following background samples are appropriate for use:
o BG-513(1-2), GWA-2D(19-20), GWA-9D(20-21.5), GWA-1O1)(9-10), SB-1(1-2),
SB-1(10-11.5), SB-1(15-16.5), SB-1(20-21.5), SB-1(25-26.5), SB-2(1-2), SB-
2(10-11.5), SB-2(20-21.5), SB-2(30-31.25), SB-2(35-36), SB-2(65-65.3), SB-3(1-
2), SB-3(10-11), SB-3(20-21.5), and SB-3(35-36.5)
The following background samples are NOT appropriate for use:
o BG-1D(0-2) — Per IHSB Guidance, this sample was taken too shallow.
o GWA-3D(5-6.5) — Sample taken in close proximity to Ash Storage 1.
o GWA-6S(9-11) — Sample taken down -gradient of Ash Basin Primary Cell
o GWA-10D(19-20) and GWA-10D(25) — Samples taken down -gradient of Ash
Storage 2.
o GWA-1113(10-11.5) — Sample taken down -gradient of Ash Storage 1.
Th dataset meets minimum requirement of 10 samples after excluding samples.
The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the
background dataset is severely limited for these constituents. Additional samples analyzed
at a lower detection limit for these parameters are necessary.
Dan River Combined Cycle Station Page 1 of 2

• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Dan River Combined Cycle Station Page 2 of 2

H. F. Lee Enerev Complex
Groundwater
• The following background wells are appropriate for use:
o AMW-11S, AMW-12S, AMW-13S, AMW-17S, IMW-01S, IMW-03S, AMW-
11BC, AMW-12BC, AMW-13BC, AMW-16BC, IMW-01BC, IMW-02BC, and
IMW-03BC.
o AMW-016BC —The location maybe near the contact with the Black Creek. Please
confirm.
The datasets for the surficial and Cape Fear flow layers meets the minimum requirement
of 10 samples.
The dataset for the Black Creek flow layer does NOT meet the requirement of 10 samples.
Additional samples are required.
The following sample event dates are NOT appropriate for use.
o AMW-12S
■ 3/1/16 — Less than 60 days from previous sample.
o AMW-13S
■ 3/1/16
—Less than 60 days from previous sample.
o AMW-12BC
■ 3/1/16
— Less than 60 days from previous sample.
o AMW-13BC
■ 3/1/16
— Less than 60 days from previous sample.
o IMW-0lBC
■ 3/4/16
— Less than 60 days from previous sample.
o IMW-02BC
• 3/3116 — Less than 60 days from previous sample.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
The following background samples are NOT appropriate for use:
o AMW-12 SB (5-6) — Sample may have been taken within 1 foot of the seasonal
high water table.
o IMW-05 SB (0-2.5) and IMW-05 SB (4-6). This location is in very close proximity
to the southeast corner of Inactive Basin 3 and possibly influenced by the presence
of the ash basin. Per IHSB Guidance, these samples were taken too shallow.
o AMW-18 SB (0-2.5) and AMW-18 SB (3-5). Samples were collected from the
core of the plume migrating from the Active Basin.
o AMW-04 SB (1-2) and AMW-04 SB (4-5). Samples are located at the western end
of the Active Basin, adjacent to the Neuse River.
o AMW-16BC (19-21).
o AMW-11 (0-2), AMW-12 SB (0-2), AMW-13 SB (0-2), and AMW-16BC (0-2) -
Per IHSB Guidance, these samples were taken too shallow.
H. F. Lee Energy Complex Pagel of 2

• The dataset does NOT meet the requirement of 10 samples. Additional samples are
required.
• The reporting limits for Antimony and Thallium were above the IHSB PSRG Protection of
Groundwater values. Therefore, the number of useable values in the background dataset
is severely limited for these constituents. Additional samples analyzed at a lower detection
limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
H. F. Lee Energy Complex Page 2 of 2

Marshall Steam Station
Groundwater
• The following background wells are appropriate for use.
o GWA-4S/D, GWA-5S/D, GWA-6S/D, GWA-8S/D, GWA-12SBR, BG-3BR, MS-
10, MW-4, and MW-4D
• The following background wells are NOT appropriate for use:
o BG-lBR — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
o GWA-12D — Recently reinstalled due to water quality issues and reevaluation as
background location is necessary before being included.
• The datasets for each flow layer meets the minimum requirement of 10 samples after
excluding samples.
• All identified sample event dates are appropriate for use.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o BG-3D(1-2), BG-313(10-12), GWA-2DA(3-5), GWA-2DA(8-10), GWA-4D(52-
53), GWA-5D(27.5-29.0), GWA-14S(3-5), and GWA-14S(8-10)
• The following background samples are NOT appropriate for use:
o GWA-1BR — Sample is within the waste boundary downgradient of the ash basin
and coal pile.
o MW-14BR — Sample is located downgradient of the ash basin and Phase I Landfill
(unlined).
• The dataset does NOT meet minimum requirement of 10 samples. Additional background
samples are required.
• The reporting limits for Antimony and Thallium were above the IHSB PSRG Protection of
Groundwater values. Additional samples analyzed at a lower detection limit for these
parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Marshall Steam Station Page 1 of 1

Mayo Steam Electric Plant
Groundwater
• The following background wells are appropriate for use:
o MW-125, BG-02, MW-12D, BG-Ol, MW-13BR, and MW-14BR
• The following background wells are NOT appropriate for use:
o MW-IOBR
• The dataset for the surficial flow layer does NOT meet the minimum requirement of 10
samples. Additional samples are needed.
• The datasets for the transition zone and bedrock flow layers meets the minimum
requirement of 10 samples.
o Provisional background threshold values for radionuclides in the transition zone
flow layer are based on a limited dataset. Additional samples are required.
• The following sample event dates are NOT appropriate for use:
o BG-01
Soil
■ 11/3/2015 —Less than 60 days from previous sample.
■ 1/8/2016 — Less than 60 days from previous sample.
• 9/8/2016 — Less than 60 days from previous sample.
■ 3/28/17 — Less than 60 days from previous sample.
o MW-10BR
■ 1M16 —Less than 60 days from previous sample.
■ 9/7/16 —Less than 60 days from previous sample.
o MW-13BR
■ 1/7/2016 — Less than 60 days from previous sample.
• 9/6/2016 — Less than 60 days from previous sample.
All identified outliers are acceptable and should be removed from the background dataset.
The following background samples are appropriate for use:
o MW-08BR (0.75-1.25), MW-08BR (25.5-26), MW-IOBR (0.75-1.0), MW-12D (1-
2), MW-12D (25-26), SB-01 (1-2), and SB-01 (13.5-14.5)
The following background samples are NOT appropriate for use:
o MW-03BR (0.8-1.25) and MW-15BR (0.5-1) — Samples taken down -gradient of
Ash Basin.
o MW-11BR (0-2) and MW-13BR (0-2) —Per IHSB Guidance, these samples were
taken too shallow.
o SB-02 (0.5-2) and SB-02 (11.0-12.5) — Boring log indicates the presence of coal
ash.
o SB-03 (5-6) and SB-03 (17-18.5) — Boring log indicates the presence of coal ash.
o SB-05 and SB-06. Sample locations were adjacent to the 1981 landfill.
The dataset does NOT meet the minimum requirement of 10 samples. Additional samples
required.
Mayo Steam Electric Plant Page 1 of 2

• The reporting limits for Antimony and Thallium were above the IHSB PSRG Protection of
Groundwater values. Therefore, the number of useable values in the background dataset
is severely limited for these constituents. Additional samples analyzed at a lower detection
limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Mayo Steam Electric Plant Page 2 of 2

Riverbend Steam Station
Groundwater
• The following background wells are appropriate for use:
o BG-lS, MW-7SR, MW-7D, BG-4S, GWA-14S, BG-41), BG-5D, and BG-5BR
o MW-71) was listed under the shallow flow laver. Please re-evaluate.
• The following background wells are NOT appropriate for use:
o GWA-5S — Groundwater water elevations were similar and sometime lower than the
historical water elevation of ash basin. Also, the wells are within compliance boundary
and not far from the waste boundary.
• The datasets for shallow meets the minimum requirement of 10 samples after excluding
samples.
• The datasets for the deep and bedrock flow layers does NOT meet the minimum requirement
of 10 samples. Additional samples are required.
• All identified sample event dates are appropriate for use.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o BG-lD (5-6), BG-1D (14-15), BG-lD (24-25), BG-2D (3.5-5), BG-2D (48-49), BG-
3D (3-5), BG-31) (18.5-20), BG-3D (23-24), GWA-51) (58.5-60), GWA-6D-1(43.5-
45), GWA-6D-2(48.5-50), GWA-21D(3.5-5), GWA-211)(8.5-10), GWA-21D(18.5-
20), GWA-21D(48.5-50), MW-7BR(43.5-45), and OB-2(38.5-40.0)
• The following background samples are NOT appropriate for use:
o GWA-3D(18.5-19) — Sample taken down -gradient of Ash and Cinder Storage Areas.
o GWA-7S(7.0-8.0) — Sample taken down -gradient of Ash Basins.
o GWA-8D(8.5-10) — Sample taken down -gradient of Ash Basins.
o GWA-9D (1), GWA-10S (8-9), and NM-15D (3.5-5) — Downgradient location and
maybe within the High Seasonal Water Table.
o GWA-20D(40-41.5) — Sample taken in close proximity to Ash Storage Area.
o GWA-22D(38.5-40.0) — Sample taken in close proximity to Ash Storage Area.
o GWA-23D(33.5-35) — Sample taken within the waste boundary of the Ash Storage
Area.
o OB-1(33.5-35.0) — Sample taken inclose proximity to Ash Basin.
• The dataset meets the minimum requirement of 10 samples after excluding samples.
• The reporting limits for Antimony, Thallium, and Selenium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the background
dataset is severely limited for these constituents. Additional samples analyzed at a lower
detection limit for these parameters are necessary
• Please state whether any background sample included fill material. Samples containing fill
should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Riverbend Steam Station Page 1 of 1

Roxboro Steam Electric Plant
Groundwater
• The following background wells are appropriate for use:
o BG-1, MW-15D, MW-18D, BG-01BR MW-IOBR, MW-14BR, MW-15BR, MW-
18BR, and MW-19BRL
• The following background wells are NOT appropriate for use:
o MW-13BR, MW-16BR, and MW-17BR
• The datasets for all flow layers meet the minimum requirement of 10 samples after
excluding samples.
• The following sample event dates are NOT appropriate for use:
o BG-01
■ 9/8/2016 — Less than 60 days from previous sample.
■ 11/16/16 —Less than 60 days from previous sample.
o BG-01BR
■ 7/9/15 — Less than 60 days from previous sample.
o MW-17BR
• 11/10/16 —Less than 60 days from previous sample.
All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o MW-08 (14-16), MW-08 (21-23), MW-13BR (22-24), MW-14BR (1-1.25), MW-
14BR (31-31.5), MW-14BR (37.5-38), MW-17 (29-31), MW-18 (31-33), and MW-
18 (37-38)
• The following background samples are NOT appropriate for use:
o MW-07 (0-2), MW-08 (0-2), MW-IOBR (0-2), MW-13BR (0-2), MW-15 (0-2),
MW-16 (0-2), and MW-18 (0-2) — Per IHSB Guidance, these samples were taken
too shallow.
• The dataset does NOT meet the minimum requirement of 10 samples. Additional samples
are required.
• The reporting limits for Antimony and Thallium were above the IHSB PSRG Protection of
Groundwater values. Samples for these two parameters need to be reported below these
values.
• Please state whether any background sample included fill material. Samples containing
fill should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
Roxboro Steam Electric Plant Page 1 of 1

�n

L. V. Sutton Energy Complex
Groundwater
• All identified background wells are appropriate for use:
o MW-05A, MW-0513, MW-3713, MW-0413, MW-05C, MW-08, MW-37C, MW-05CD,
MW-05D, MW-37D, MW-05E, and MW-37E
o Lower Surficial Aquifer — An adequate dataset has been provided for all constituents,
with the exception chromium (VI). Additional samples are planned for collection to
bring the total number of valid chromium (VI) samples to ten by second quarter 2017.
• The datasets for the upper and lower surficial flow layer meet the minimum requirement of 10
samples.
• The dataset for the Upper Peedee flow layer does NOT meet the minimum requirement of 10
samples. Additional samples are planned for collection to bring the total number of valid
samples to ten (second quarter 2017 at the earliest). It was agreed upon to use a pH of less than
or equal to 9.7 S.U. as the upper threshold for these zones in the Peedee aquifer.
• The dataset for the Lower Peedee flow layer does NOT meet the minimum requirement of 10
samples. New and replacement wells have been added to the groundwater monitoring network
(MW-5R-E, MW-8E, MW-41E). Additional samples are planned for collection to bring the
total number of valid samples to 10 (second quarter 2017 at the earliest). It was agreed upon
to use a pH of less than or equal to 9.7 S.U. as the upper threshold for these zones in the Peedee
aquifer.
• All identified sample event dates are appropriate for use.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
• The following background samples are appropriate for use:
o AW-02C (10-11) and MW-37C (4-6)
• The following background sample are NOT appropriate for use:
o AW-01C (0-2), AW-02C (0-2), AW-03C (0-2), AW-04C (0-2), AW-06D (0-2), AW-
07D (0-2), MW-37C (0-2), SMW-01C (0-2), SMW-02C (0-2), SMW-03C (0-2),
SMW-04C (0-2), SMW-05C (0-2), and SMW-06D (0-2) — Per IHSB Guidance, these
samples were taken too shallow.
o AW-05C (4-6) and AW-05C (9-11) —Samples are down -gradient of the ash pond.
• The dataset does NOT meet the minimum requirement of 10 samples. Additional samples are
require .
• The reporting limits for Antimony, Cobalt, and Thallium were above the IHSB PSRG
Protection of Groundwater values. Therefore, the number of useable values in the background
dataset is severely limited for these constituents. Additional samples analyzed at a lower
detection limit for these parameters are necessary.
• Please state whether any background sample included fill material. Samples containing fill
should be omitted from the raw background dataset.
• All identified outliers are acceptable and should be removed from the background dataset.
L. V. Sutton Energy Complex Page 1 of 1

W.H. Weatherspoon Power Plant
Groundwater
• All identified background wells are appropriate for use.
o BW-02S, BW-03S, CCR-101-13G, MW-01, BW-03I, and BW-03D
• The dataset for the surficial flow layer meets the minimum requirement of 10 samples
• The dataset for the Lower Yorktown does NOT meet the minimum requirement of 10
samples. Additional samples are required.
• The dataset for the PeeDee does NOT meet the minimum requirement of 10 samples.
Additional samples are required.
• The following sample event dates are NOT appropriate for use.
o BW-03S
■ 3n116 — Less than 60 days from previous sample.
• All identified outliers are acceptable and should be removed from the background dataset.
Soil
No soil background data was provided. Please coordinate the collection of background
soil data with the DWR Fayetteville Regional Office.
W. H. Weatherspoon Power Plant Page 1 of I

K`
Water Resources
Environmental Quality
October 11, 2017
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. JAY ZIMMERMAN
Director
Subject: Approval of Provisional Background Threshold Values for Allen Steam Station,
Asheville Steam Electric Plant, Buck Combined Cycle Station, Cape Fear Steam
Electric Plant, James E. Rogers Energy Complex, Dan River Combined Cycle
Station, H. F. Lee Energy Complex, Marshall Steam Station, L. V. Sutton Energy
Complex, and W. H. Weatherspoon Power Plant
Dear Mr. Draovitch:
The North Carolina Department of Environmental Quality's Division of Water Resources (DWR)
has reviewed Duke Energy's calculated provisional background threshold values (PBTVs) for soil
and groundwater for the subject facilities. DWR calculated PBTVs based on the vetted
background data in the letter to Duke Energy dated July 7, 2017, using the Revised Statistical
Methods for Developing Reference Background Concentrations for Groundwater and Soil at Coal
Ash Facilities dated May 26, 2017 and any subsequent information provided.
Per 15A NCAC 02L .0202(b)(3), where naturally occurring substances exceed the established
standard, the standard shall be the naturally occurring concentration as determined by the Director.
Therefore, PBTVs that are calculated to be above the 15A NCAC 02L .0202 groundwater
standards or Interim Maximum Allowable Concentrations (IMACs) and accepted by DWR shall
become the enforceable groundwater standard. Otherwise, the enforceable groundwater standards
shall be those listed under 15A NCAC 02L .0202(h) including any effective IMACs.
The attachments document DWR's concurrence/non-concurrence with Duke Energy's calculated
PBTVs for groundwater and soil. For all Duke Energy's calculated PBTVs that DWR finds
acceptable, DWR hereby approves those values. If DWR does not find the Duke Energy's
calculated PBTVs acceptable, justification is provided on the attachments. Duke Energy will be
responsible to provide revised values for DWR to review and approve.
Please note that the approved PBTVs are based on the current data available. DWR recognizes
that, as new data is gathered going forward, the approved PBTVs may be refined. Thus, there will
be need for a periodic review of the data and recalculation of the PBTVs. The timeframes for the
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional operations Section
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

periodic review will established by DWR at a later date and any revised PBTVs will be subject to
approval by the DWR's Director.
Along with the specific comments provided on the attachments, DWR offers the following general
comments with regards to the PBTVs
In cases where the PBTVs calculated by Duke Energy use groundwater and soil samples
that have less than 10 samples, the calculated values are acceptable per the guidance
provided in the Revised Statistical Methods for Developing Reference Background
Concentrations for Groundwater and Soil at Coal Ash Facilities dated May 26, 2017.
However, these calculated values may be open to revision by DEQ once additional valid
samples are collected.
Outliers are identified with three statistical lines of evidence: Box Plots, Q-Q Plots, and
95% Significance Levels. Based on these lines of evidence, if Duke Energy chooses not
to exclude an outlier, then additional rationale or justification shall be provided for DWR
review.
The PSRG for Chromium that will be applied shall be the more conservative value for
Chromium (VI) which is 3.8 mg/kg.
If you have any questions, please contact Debra Watts at [phone].
Sincerely,
�-elcc
JSIZiennanP.G., Director
Division of Water Resources
Attachments
cc: WQROS Regional Office Supervisors
WQROS Central File Copy

Allen Steam Station - Groundwater Provisional Background
Threshold Values
Parameter
Reporting
Units
Duke Ener t Calculated PBTVs
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flo% Unit
Flow Unit
Shallow
Deep I
Bedrock
Shallow
Deep
Bedrock
pH
S.U.
5.2 -7.5
6.7.8.4
7.5 - 7.8
6.5-8.5
Acceptable
Acceptable
Acceptable
Deep and bedrock data set is insufficient and must be updated with additional data.
Alkalinity
mg/L
188.773
74
83.4
NE
Acceptable
Acceptable
Acceptable
Aluminum
µg L
427
540
301
NE
Acceptable
Acceptable
Acceptable
Antimony
0.876
0.69
0.5
1
Acceptable
Acceptable
Acceptable
Arsenic
0.42
1.4
_
0.4
10
Acceptable
Acceptable
Acceptable
Barium
pg/L
78
52.4
21
700
Not Acceptable
Acceptable
Acceptable
Duke revised shallow value - 125.4 ug/L. Please revise table accordingly.
Deep and bedrock data set is insufficient and must be updated with additional data.
Beryllium
g/L
0.127
0.2
0.1
4
Acceptable
Acceptable
Acce table
Deep and bedrock data set is insufficient and must be updated with additional data.
Bicarbonate
mg/L
I88.',73
74 1
83.4
NE
Acceptable
Acceptable
Acceptable
Boron
WL
50
50
50
700
Acceptable
Acceptable
Acceptable
Cadmium
0.08
U.08
11.08
2
Acceptable
Acceptable
Acceptable
Calcium
mg/L
20
14.2
20.4
NE
Acceptable
Acceptable
Acceptable
Carbonate
mg/L
5
5
5
NE
Acceptable
Acceptable
Acceptable
Chloride
mg/L
10.9
6
Lb
250
Acceptable
Acceptable
Acceptable
Chromium (VI)
µg/L
7J42
1.2
0.2.3
NA
Acceptable
Acceptable
Acceptable
Duke should verify that only Chromium (VI) data was evaluated to establish value.
Deep and bedrock data set is insufficient and must be updated with additional data.
Chromium
@/L
1 6.927
6.8
5.6
10
Acceptable
Acceptable
Acceptable
Deep and bedrock data set is insufficient and must be updated with additional data.
Cobalt
4.338
0.5
0.27
1
Acceptable
Acceptable
Acceptable
Copper
2.265
1.7
1.2
1000
Acceptable
Acceptable
Acceptable
Iron
834.8
555
294
300
Acceptable
Acceptable
Acceptable
Lead
kmg/L
0. tt__
5.61
0.1
0.1
15
Acceptable
Acceptable
Acceptable
Magnesium
I 4.58
4.75
NE
Acceptable
Acce table
Acceptable
Manganese
577.9
60A
39.1
50
Acceptable
Acceptable
Acceptable
Memu
D.2
2.4
" 0.2
1
Acceptable
Acceptable
Acceptable
Methane
WL
11.4
.3 .9
10
NE
Acceptable
Acceptable
Acceptable
Page 1 of 2

Allen Steam Station - Groundwater Provisional Background Threshold Values
Parameter
Reporting Units
Duke Energl Calculated PBTVs
Flow Unit
15A NCAC 02L
Standard or
]MAC
DWR Concurrence(Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Dee
Bedrock
Shallow
Dee
Bedrock
Molybdenum
y
µ91L
+
30._
4.4
NE
Acceptable
Not Acceptable
Acceptable
Duke should verify deep value with geometric mean and revise if needed.
D and bedrock data set is insufficient and must be updated with additional data.
Nickel
4.024
4.024
R.I
3.4
100
Acceptable
Acceptable
Acceptable
Deep and bedrock data set is insufficient and must be updated with additional data.
Nitrate + Nitrite
mg-N/L
1.8
0.94
0.41
11•
Acceptable
Acceptable
Acceptable
Potassium
mg/L
5.24
_
9.89
6.06
NE
Acceptable
Acceptable
Acceptable
Selenium
g/L.
0.5
0.5
0.5
20
1 Acceptable
Acceptable
Acceptable
Sodium
Strontium
mg/L
15.2.19
286
28.3
200
7.71
106
NE
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acce table
Sulfate
mg/L
31,41
1 16.2
2.9
250
Acceptable
Acceptable
Acceptable
Sulfide
mg/L
0.1
_
0.12
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
mg/L
180.957
12ti
147
500
Acceptable
Acceptable
Acceptable
Thallium
µg/L
0.1
0.1
0.1
0.2
Acceptable
Acceptable
Acceptable
TOC
mg/L
18.022
11
5.6
NE
Acceptable
Not Acceptable
Acceptable
Duke should verify deep value with geometric mean and revise if needed.
Deep and bedrock data set is insufficient and must be updated with additional data.
Vanadium
L
5.33
9.6
10.8
1 0.3
1 Acceptable
Acceptable
I Acceptable
Deep and bedrock data set is insufficient and must be updated with additional data.
Zinc
pg/L
R0.02
17J
15 t
1000
Acceptable
Not Acceptable
Not Acceptable
Duke should verify deep and bedrock value with geometric mean and revise if needed.
Deep and bedrock data set is insufficient and must be updated with additional data.
Radium (Total)
Umnium(Total)
pci/
p mL
1 iR6
0.001037
0.613
0.0005
1.103
0.00039
NE
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Deep and bedrock data set is insufficient and must be updated with additional data.
NA - Not Applicable
NO - Not Detected
NE - Not Established
mglL - milligrams per liter
pCi/L - picocuries per liter
Radium (Total) - Radium-226 and Radium-228 combined
* lie 15A NCAC 02L Standard is 10 mg/L for Nitrate and I mg/L for Nitrite (added for a anal of I I mg/L)
S.U. -Standard Unit "Duke plans to update the shallow and deep data set in the near future. PBNs will be revised accordingly. Bedrock flow
layer data set will remain insufficient until additional sampling events are completed.`•
TOC - Total Organic Carbon
TDS - Total Dissolved Solids
pg/mL - micrograms per milliliter
pg/L - micrograms per liter
Uranium (Total) - Uranium-233. Uranium-234. Umnium-236. and Uranium-238 combined
Page 2 of 2

Allen Steam Station - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Fuergy
Calculated
PBI,vs
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
3.3_- 6.8
NE
Acceptable
Aluminum
mg/kg
_ _
26991
NE
Acceptable
Antimony
mg/kg
N A
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mgfkg
3.7
5.8
Acceptable
Only 5 valid samples in data set.
Barium
mglkg
233
580
Acceptable
Beryllium
mg/kgmg/kg
1.304
63
Not Acceptable
Normal UTL - 1.78 mg/kg.
Boron
mg/kg
23.4
45
Acceptable
Only 9 valid samples in data set.
Cadmium
mg/kgmg/kg
0.368
3
Acceptable
Calcium
mg/kgmg/kg
1192
NE
Not Acceptable
Normal UTL - 859.9 mg/kg.
Chloride
mg/kgmg/kg
ND
NE
Acceptable
Chromium
mg/kgmg/kg
93.57
3.8
Not Acceptable
Normal UTL - 20.42 m
Cobalt
mg/kgmg/kg
48.6
0.9
Acceptable
Copper
mgIkg
78 15
700
Acceptable
Iron
mg/kgmg/kg
69316
150
Acceptable
Lead
mg/kgmg/kg
12.31
270
Acceptable
Magnesium
m
15100
NE
Acceptable
Manganese
mg/kg
_ _
1786
65
Acceptable
Mercury
mglkg
0.0233
1
Acceptable
Molybdenum
mgkg
4.6
NE
Acceptable
Nickel
mg/kgmg/kg
9.079
130
Not Acceptable
Log UTL - 10.91 m
Nitrate as N)
mg/kgmg/kg
ND
NE
Acceptable
Potassium
mg/kg
_ 13742 _
NE
Not Acceptable
Normal UTL - 14,097 mg/kg.
Selenium
mg/kg
NA
2.1
Not Acceptable
Use PSRG of 2.1. To be revised when valid data set is available.
Sodium
mg/kgmg/kg
_
461
NE
Acceptable
Strontium
me/kg
24.91
NE
Not Acceptable
Normal UTL - 14.41 mg/kg.
Sulfate
m kg
♦n
NE
Acceptable
Thallium
mg/kg
N A
0.28
Not Acceptable
Use PSRG of 0.28. To be revised when valid data set is available.
Vanadium
mg/kg
_
I.t2.2
6
Acceptable
Zinc
mg/kg
112.1
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

Asheville Steam Electric Plant- Groundwater Background Threshold Values
Parameter
Reporting Units
Uuke Enerq Calculated PRIVs
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acce table/Not Acceptable)
Comments
Flow I:nit
Flow Unit
Alluvium ShallowF14.75
Bedrock
Alluvium
Shallow
Dee
Bedrock
H
S.U.
4.6-5.1 43.$.8
4.1-8.1
6.5-8.5
Acceptable
Acceptable
Acceptable
Acceptable
Alkalinity
m L
10.9 t4.2
70A
NE
Acceptable
Acceptable
Acceptable
Acceptable
Aluminum
L
73 602.2
199.3
NE
Accetable
Acce table
Acce table
A table
Antimon
µg/L
I �1
I
I.
Ac table
Acce table
Acc table
Acc table
Arsenic
I t I
1
10
Acceptable
Acceptable
Acceptable
Acceptable
Barium
µg/L
50 14a
41.16
700
Ac table
Acce table
Acc table
Acc table
B Ilium
µg/L
t1
1
4
A table
Acce table
Acce table
Acc table
Bicarbonate
Boron
mg/L
119fl,
10.9 1i
50 so -�
50
70A
50
NE
700
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Cadmium
_
1 __ _ "1_
2.6� _ Inn 1913
5 5 5
2
Acceptable
Acceptable
Acceptable
Acceptable
Calcium
mg/L
_ 24_I';_
5
NE
Acceptable
Acceptable
Acceptable
Acceptable
Carbonate
m
NE
Acceptable
Acceptable
Acceptable
Acceptable
Chloride
m
_
IS
_
l4
6.7
_
6.5
250
Acceptable
Acceptable
Acceptable
Acceptable
Chromium (VI)
1191
OAI
1313
0.261
0.423
NA
Acceptable
Ac table
Acceptable
Acceptable
Chromium
5
5
1 z2
_
1.1
10
Acceptable
Acceptable
Acceptable
Acceptable
Cobalt
AWL
429
S.ti.52
4.661, 1
1
Acceptable
Not Acceptable
Acceptable
Acceptable
Shallow: non -parametric distribution; 95% UTL (bootstrap and BCA bootstrap avenge) with 95% coverage = 6.9.
copper
5
5
i.Ox f- 1
1000
Acceptable
Acceptable
Acceptable
Acceptable
Iron
µg'L
598
_1050 1785- 1246
_ I _ _1 1
_R= T 3 371 t 330
725 380 104.7
03 0.2 0.05
300
Acceptable
Not Acceptable
Not Acceptable
Acceptable
Shallow: gamma distribution; 95% UTL (WE and HW avenge) with 95% coverage = 941.
Deep: notmaldistribution; 95%UTLwith95%coven a=779.
Lead
1191L
I
15
NE
50
Acceptable
Acceptable
Acceptable
Acceptable
A table
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Not Acceptable
Bedrock: non-pammetric distribution; 95% UTL (bootstrap and BCA bootstrap average) with 95% coverage = 93.
Magnesium
Manganese
mg/L
119/1.
3,86
363
Mercury
L
0.1
1
Acceptable
Acceptable
Acceptable
Acceptable
Methane
µg1-
230
10
10
Ill
NE
Not Acceptable
Acceptable
Acceptable
Acceptable
Alluvium: 230 is an outlier and Should be removed from dataset; normal distribution, 95% UTL with 95% coverage =
128.
Molybdenum
µPL
1
_ _ 1 I _ 3.7
t-- _ 10 u,82c 1.77
_ 2,4 0 RT__ _ _0.422
Lot 1.871 _ 4.785
1.88 I _t _ 1
_�._-
4.D6 _ 11 �; 9.013
93.98 _.i ➢'. Gi 88
50 _5_46' S.n
_ 6.1 _ 0.1 - _01 _
IU4p ! I II c
_. .r
0.2 _ 11.2 __ U.2
0.70R 0 599 _ LI02
0.625 0.41 OA32
NE
Acceptable
Acceptable
Acceptable
Acceptable
Nickel
g'L
5
100
le
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
m -N/L
0.113
11°
le
Acceptable
Acceptable
Acceptable
Potassium
mg/L
MR5
NE
20
le
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Selenium
f
Sodium
m
6.18
NE
le
Acceptable
Acceptable
Acceptable
Strontium
µ
20
NE
le
Acce table
Acce table
Acce table
Sulfate
m L
4,6
11.1
56
0,2
250
le
Acceptable
Acceptable
Acceptable
Sulfide
mg/L
NE
Acceptable
Acceptable
Acceptable
Acceptable
TDS
mg/L
500
Acceptable
Acceptable
Acceptable
Acceptable
Thallium
0.2
Acceptable
Acceptable
Acceptable
Acceptable
TOC
m L
0.72
NE
Acceptable
Acceptable
Acceptable
Acceptable
Vanadium
'L
03
0.3
Acceptable
Acceptable
Acceptable
Acceptable
Zinc
µg�L
22 45.4 27.57
5
1000
Acceptable
Acceptable
Acceptable
Acceptable
Radium (Total)
Ci/L
4.17 6.832 6.61
6554
NE
Acceptable
Acceptable
Acce table
Not Acce table
Bedrock: normal distribution; 95%UTL with 95%coven a=5.8.
Unnium(TmaT)
µ mL
O.OIro35 O.D0035 0.1100402
6.09045396
NE
A table
Acce table
Acce table
Acce table
NA -Not Applicable
ND -Not Detected
NE . Not Established
mg/L - milligrams per liter
pCi/L - picocuries per liter
Radium (Total)- Radium-226 and Radium-228 combined
-The 15A NCAC 02L Standard is 10 mg/L for Nitrate and l mg/L for Nitrite (added for a total of 11 mg/L)
S.U. - Standard Unit
TUC - Total Organic Carbon
TDS - Total Dissolved Solids
µg/mL. micrograms per milliliter
µg(L - micrograms per liter
Uranium (Total)- Umnium-233, Uranium-234, Uranium-236, and Umnium-238 combined

Asheville Steam Electric Plant - Soil Background Threshold Values
Parameter
Reporting
Units
Duke Fnergv
Calculated PB'1'l's
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not Acceptable)
Comments
H
S.U.
3.4 - 8.9
NE
Acceptable
Aluminum
mg/kg
33951
NE
Acceptable
Antimony
mg/kg
NA
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mg/kg
5.06
5.8
Acceptable
Barium
mg/kg
219.9
580
Acceptable
Beryllium
mg/kg
1.959
63
Acceptable
Boron
mg/kg
36.6
45
Acceptable
Cadmium
mg/kg
ti D
3
Not Acceptable
Use PSRG of 3. To be revised when valid data set is available.
Calcium
mg/kg
1295
NE
Acceptable
Chloride
mg/kg
NI)
NE
Acceptable
Chromium
mg/kg
64.89
3.8
Acceptable
Cobalt
mg/kg
49.6_2
0.9
Acceptable
Copper
mg/kg
_
76.6
700
Acceptable
Iron
mg/kg
53379
150
Acceptable
Lead
mg/kg
71.04
270
Acceptable
Magnesium
mg/kg
9673
NE
Acceptable
Manganese
mg/kg
1228
65
Acceptable
Mercury
mg/kg
0.070'
1
Acceptable
Molybdenum
mg/kg
ND
NE
Acceptable
Nickel
mg/kg
2758
130
Acceptable
Nitrate (as N)
mg/kg
NI)
NE
Acceptable
Potassium
mg/kg
4754)
NE
Acceptable
Selenium
mg/kg
7
2.1
Acceptable
Sodium
mg/kg
NI)
NE
Acceptable
Strontium
mg/kg
7.756
NE
Acceptable
Sulfate
mg/kg
N1)
NE
Acceptable
Thallium
mg/kg
NA
0.28
Not Acceptable
Use PSRG of 0.28. To be revised when valid data set is available.
Vanadium
mg/kg
_
82.78
6
Acceptable
Zinc
mg/kg
218.5
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

Buck Combined Cycle Station - Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
_Duke Energy Calculated PBTVs
—
I7ow Enit
15A NCAC 02L
Standard or
MAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
—
Shallow
Dec
Bedrock
Shallow
Deep
Bedrock
pH
S.U.
4.5 - 6.4
5.9 - SA 1
5.8 - 7.8
6.5-8.5
Acceptable
Acceptable
Acceptable
Alkalinity
mg2
67.3
70.4
72
NE
Not Acceptable
Not Acceptable
Acceptable
Duke revised shallow - Gamma 117.2 ug/L and deep - Gamma 80.2 ug/L.
Please revise table accordingly.
Aluminum
µg/L
_
272.8
404
240
NE
Acceptable
Acceptable
Acceptable
Antimony
µg/L
I
1
1
1
Acceptable
Acceptable
Acceptable
Arsenic
µg/L
I
1
1
10
Acceptable
Acceptable
Not Acceptable
Duke revised bedrock - Gamma 3.3 ug/L. Please revise table accordingly.
Barium
µg/L
43.5
19
90.8
700
Not Acceptable
Acceptable
Acceptable
Duke agreed Shallow Nomal UTL - 50.6 ug/L.
Beryllium
µg L
0.139
1
0.2
4
Not Acceptable
Acceptable
Acceptable
Duke utilized Gamma UTL for shallow - 0.81 ug/L. Please revise table
accordin I .
Bicarbonate
mg/L
92.261
84.371
72
NE
Acceptable
Acceptable
Acce table
Boron
L
50
50
50
700
Acceptable
Acceptable
Acce [able
Cadmium
L
1
1
1
2
Acceptable
Acceptable
Acceptable
Calcium
mg/L
13.1
14
13.3
NE
Acceptable
Acceptable
Acceptable
Carbonate
mg/L
5
5
5
NE
Acceptable
Acceptable
Acceptable
Chloride
mg/L
7.559
_
4.454
4.818
250
Acceptable
Acceptable
Acceptable
Chromium (VI)
g/L
2.428
0.5
1.20
NA
Acceptable
Acceptable
Acceptable
Chromium
g/L
5.04
5
3.603
10
Acceptable
Acceptable
Acceptable
Cobalt
L
8.345
0.297
0.289
1
Acceptable
Acceptable
Acceptable
Copper
L
4.431
5
5.164
1000
Acceptable
Acceptable
Iron
L
64fiA
499.9
1 146.6
300
Acce table
Acceptable
Lead
µg/L
1
1
I
15
Acceptable
Acce table
n
Ma esium
m L
8.68
5.859
7.59
NE
Acc table
Acce table
Manganese
g/L
197.9
7
7
50
Acce table
Acce table
Page 1 of 2

Buck Combined Cycle Station - Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
fluke Energv Calculated PBTVs
Flow Unit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Deep
Bedrock
Shallow
Deep
Bedrock
Mercury
g/L
0.05
0.05
0.05
1
Not Acce table
Not Acceptable
Not Acceptable
Shallow, deep, and bedrock Non -Par. UTL - 0.2 u L.
Methane
µg/L
10
10
10
NE
Acceptable
Acceptable
Acceptable
Molybdenum
1
2
5.9
NE
Acceptable
Acceptable
Acceptable
Nickel
L
7.2
5
5
100
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
m -N/L
0.4
2
0.8712
ll*
Acceptable
Acceptable
Acceptable
Potassium
m
5
6.89
6.613
NE
Acceptable
Acceptable
Acceptable
Selenium
µg/L
1
1
1
20
Acceptable
Acceptable
Acceptable
Sodium
mg/L
8.22
13
9.8
NE
Acceptable
Acceptable
Acceptable
Strontium
µg/L
108
129
98.5
NE
Acceptable
Acceptable
Acceptable
Sulfate
m
3.3
6.7
2.4
250
Acceptable
Acceptable
Acceptable
Sulfide
m
0.1
0.1
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
mg/L
212.02
130
145.049
500
Acceptable
Acceptable
Acceptable
Thallium
µg/L
0.2
0.2
1 0.2
0.2
Acceptable
Acceptable
Acceptable
TOC
mg/L
1100
1
1600
NE
Not Acceptable
Acceptable
Not Acceptable
Shallow background value should be 1.1 ug/L. Please revise accordingly.
Duke should verify bedrock value with geometric mean and revise if needed.
Vanadium
g/L
7.69
8.418
14.12
0.3
Acceptable
I Acceptable
Acceptable
Zinc
µg/L
26.39
10
17.4
1000
Acceptable
Acceptable
Acceptable
Radium (Total)
Ci/L
1.608
0.6
1.6
NE
Acceptable
Acceptable
Acceptable
Uranium Total
mL
0.0005
0.0005
0.0005
1 NE
Acceptable
Acceptable
Acceptable
NA - Not Applicable
ND - Not Detected
NE - Not Established
mg/L - milligrams per liter
pCi/L - picocuries per liter
Radium (Total) - Radium-226 and Radium-228 combined
*The 15A NCAC 02L Standard is 10 mg/L for Nitrate and I mg/L for Nitrite (added for a total of 11 mg/L)
S.U. - Standard Unit
TOC - Total Organic Carbon
TDS - Total Dissolved Solids
µg/mL - micrograms per milliliter
µg/L - micrograms per liter
Uranium (Total) - Uranium-233, Uranium-234, Uranium-236, and Uranium-238 combined
Page 2 of 2

Buck Combined Cycle Station - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calculated
PB'CN s
PSRG Protection
PSRG
of Groundwater
Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
4.1 - 6.7
NE
Acceptable
Aluminum
M&g
25978
NE
Acceptable
Antimony
m
NA
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mg/kg
1.7
5.8
Acceptable
Only3 valid samples in data set.
Barium
m
_
U2.9
580
Acceptable
Beryllium
mg/kg
2.8
63
Not Acceptable
Gamma UTL - 4.52 mg/kg.
Boron
mg/kg
_
56.3
45
Acceptable
Cadmium
mg/kg
ND
3
Acceptable
Calcium
m
718
NE
Not Acceptable
Normal UTL - 999.1 mg/kg.
Chloride
mg/kg
ND
NE
Acceptable
Chromium
mg/kg
24,64
3.8
Acceptable
Cobalt
m
46.5
0.9
Acceptable
Copper
mg/kg
88.76
700
Acceptable
Iron
mg/kg
78988
150
Acceptable
Lead
mg/kg
15.36
270
Acceptable
Magnesium
m
33058
NE
Not Acceptable
Normal UTL - 14,554 mg/kg.
Manganese
mg/kg
1748
65
Acceptable
Mercury
mg/kg
0.0778
1
Acceptable
Molybdenum
mg/kg
ND
NE
Acceptable
Nickel
mg/kg
15.85
130
Acceptable
Nitrate as N)
mg/kg
ND
NE
Acceptable
Potassium
mg/kg
21444
NE
Not Acceptable
Normal UTL - 21,063.5 mg/kg.
Selenium
mglkg
N:%
2.1
Not Acceptable
Use PSRG of 2.1. To be revised when valid data set is available.
Sodium
ND
NE
Acceptable
Strontium
9.869
NE
Acceptable
Sulfate
ND
NE
Acceptable
Thallium
:iMjg/1Cg
N.4
0.28
Not Acce table
Use PSRG of 0.28. To be revised when valid data set is available.
Vanadium
202.6
6
Acc tableZinc
105.4
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

Cape Fear Steam Electric Plant - Groundwater Provisional Background Threshold Values
Re
Rep MIS
Uuke b nugr (alauldcd PBI l's
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
host I nit
Flow Unit
._
SurFicial Bedrock
Surlieial
Bedrock
pH
S.U.
5.8 - 6.4 _5.5 - %.2
6.5-8.5
Acceptable
Acceptable
Alkalinity
mg/L
206 _ 237 Y _
323._3 _ _ _ 11%
I I _
3 6
NE
Acceptable
Acceptable
Aluminum
µg/L
NE
Acceptable
Acceptable
Antimony
Arsenic
L
l
10
Acceptable
Acceptable
Acceptable
Acceptable
Barium
_
183 _ 471
1 1
20M1 235
700
Acceptable
Acceptable
Beryllium
µg/L
4
Acceptable
Acceptable
Bicarbonate
m
NE
Acceptable
Acceptable
Boron
a
_ _ _
177 _ so
700
Acceptable
Acceptable
Cadmium
L
_ _ _
1 1_
2
NE
Acceptable
Acceptable
Acceptable
Acceptable
Calcium
mg/L
__ _
82.6
Carbonate
mgfL
5
_ _6.2b
5
NE
Acceptable
Acceptable
Chloride
mg/L
250
22o
250
Acceptable
Acceptable
Chromium (VI)
11911,
0.12
0!�3
NA
Acceptable
Acceptable
Chromium
pgfL
1
_ _
I
10
Acceptable
Acceptable
Cobalt
L
89
1.15
1
Acceptable
Acceptable
Copper
L
4
1
1000
Acceptable
I Acceptable
Iron
µg/L
375W
_ _
910
300
Acceptable
Not Acceptable
RRO calculated value of 750 ug/L for bedrock. Removed 4230, 2290, 1800, and 1220 as outliers. Duke Energy
notified ofdiscrepancy by email on 9-15-17
Lead
L
1
1
15
Acceptable
Acceptable
Magnesium
mg/L
32 c
30.8
NE
Acceptable
Acceptable
Manganese
g/L
9170
991
50
Acceptable
Acceptable
Mercury
L
0.05
0.05
1
Acceptable
Acceptable
Methane
L
1 10
25
NE
Acceptable
Acceptable
Molybdenum
L
1
11.5
NE
Acce table
Acceptable
Nickel
µg/L
78.11
2
100
Not Acceptable
Acceptable
RRO calculated value of48 ug/L. for surficial. Removed 150 as outlier. Duke Energy notified ofdiscrepacy by
email on 9-15-17
Nitrate -Nitrite
m -N/L
1.61
2.49
Il*
Acceptable
Acceptable
Potassium
mg/L
1
2.49
NE
Acceptable
Acceptable
Selenium
g/L
1
1."
20
Acceptable
Acceptable
Sodium
m
190
725
NE
Acceptable
Acceptable
Strontium
+L
994
a06
NE
Acceptable
Acceptable
Sulfate
I m 'L
510
1 %
250
Acceptable
Acceptable
Sulfide
mg/L
0.1
0.1
NE
Acceptable
Acceptable
TDS
m L
1200
675
500
Acceptable
Acceptable
Thallium
0.2
_
0.2
0.2
Acce table
Acceptable
TOC
m9fL
6.3 _
13
NE
Acceptable
Acceptable
Vanadium
L
1.268
2.37
0.3
Acceptable
Acceptable
Zinc
L
62
5
1000
Acceptable
Acceptable
Radium (Total)
pCi/L
3.459
NE
Acceptable
Acceptable
Uranium (Total)
g'mL
__1.03 _
O.01b"
0.00196
NE
Acceptable
Acceptable
NA. Not Appkeable
ND - Not Detected
NE - Not Established
mg/L- milligrams per liter
pCJL-picocuries per liter
Radimn (Total) . Radimn.226 and Radium-228 coinbeed
*The 1 SA NCAC 02L Standard is 10 mall, for Nitrate and I mg/L for Nitrite (added for a total of I I mg/L)
S.N. - Staudard Brut
TOC - Total Organic Cuban
TDS - Total Dissolved Solids
µghn]. - microgrmms per milliliter
pall. - micrograms per liter
❑mnimn (Total) - Uranium-233, Umnimn-234, Uranimn-236, and Uranium-238 combined

Cape Fear Steam Electric Plant - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calcualated
PB'iVs
of PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
pH
S.U.
5.2-6.7
NE
Acceptable
The PBTV was based on either the highest value or if the highest value is above an order of magnitude greater than
the geometric mean of all values, then the highest value should be considered an outlier and removed from further
use and the PBTV is computed to be the second highest value.
Aluminum
mg/kg
44400
NE
Acceptable
Antimony
mg/kg
0.177
0.9
Acceptable
Arsenic
mg/kg
8.1
5.8
Acceptable
Barium
mg/kg
224
580
Acceptable
Beryllium
mg/kg
1.2
63
Acceptable
Boron
mg/kg
14.4
45
Acceptable
Cadmium
mg/kg
0.69
3
Acceptable
Calcium
mg/kg
2750
NE
Acceptable
Chloride
mg/kg
301
NE
Acceptable
Chromium
mg/kg
40.4
360000
Acceptable
Cobalt
mg/kg
31.9
0.9
700
Acceptable
Acceptable
Copper
mg/kg
17.4
Iron
mg/kg
2%0
150
Acceptable
Lead
mg/kg
26.1
270
Acceptable
Magnesium
mg/kg
3420
NE
Acceptable
Manganese
mg/kg
370
65
Acceptable
Mercury
marJka
0.113
1
Acceptable
Molybdenum
mg/kg
3.3
NE
Acceptable
Nickel
mg/kg
9.2
130
Acceptable
Nitrate (as N)
mg/kg
30.1
NE
Acceptable
Potassium
mg/kg
427
NE
Acceptable
Selenium
mg/kg
4.4
2.1
Acceptable
Sodium
mg/kg
338
NE
Acceptable
Strontium
I mg/kg
35.8
NE
Acceptable
Sulfate
mg/kg
301
250
Acceptable
Thallium
mg/kg
0.349
0.28
Acceptable
Vanadium
mg/kg
I
42
6
Acceptable
Zinc
mg/kg
154
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

James E. Rogers Energy Complex- Groundwater Provisional ackground Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PBM
Flo% Unit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Shalon,
Ikeep
Bedrock
Shallow
Deep
Bedrock
pH
S.U.
4.4-6.1
41.E-6.1
5.4-7A
6.5-8.5
Acceptable
Acceptable
Acceptable
Alkalinity
m
13.67
19.74
53
NE
Acceptable
Acceptable
Acceptable
Aluminum
WL
253
290
208.2
NE
Acceptable
Acceptable
Acceptable
Antimony
µg/L
1
I
1
1
Acceptable
Acceptable
Acceptable
Arsenic
WIL
I
1.303
1
10
Acceptable
Acceptable
Acceptable
Barium
µglL
73.03
23
A933
700
Acceptable
Acceptable
Acceptable
Beryllium
L
0.188
0.2
1
4
Acceptable
Acceptable
Acceptable
nate
mg(L
14.42
18.13
68.92
NE
Acceptable
Acceptable
Acceptable
50
50
50
700
Acceptable
Acceptable
Acceptable
m
1
I
1
2
Acceptable
Acceptable
Acceptable
mg/L
3.221
I1
16
NE
Acce table
Acce table
Acceptable
te
m
5
5
5
NE
Acc table
Acc table
Ac fable
m
7.7
5.1 RAM
6.16 0.12
250
Acceptable
Acceptable
Ac table
m (vq
0.4.42
NA
Acceptable
Acc table
Acceptable
m
µg(L
3.96R 1'91 r567
_10.65 _ 9 041 _ 1 497
6.5ao n4-r '- 5
7653 ! 5.96220
1 _ I_ �1
2.4-4 _ 1.6 2.328
16X.6 _ _'8 zl 80.4
0.2 U2 f 0.2
10
Acce table
Acc table
Acceptable
1
Acceptable
Not Acceptable
Acceptable
Deep: non -parametric distribution; 95% UTL (bootstrapand BCA bootstrapaverage) with 95% -coverage = 5.1.
Copper
1000
Acceptable
Acceptable
Ac mble
Iron
Lead
µg/L
300
Not Acceptable
Not Acceptable
Acceptable
Shallow: log normal distribution; 95% UTL with 95% coverage = 684.
Deep: no -parametric distribution; 95% UTL(bootstrap and BCA bootstrap averse with 95%coverage =515.
IS
Acceptable
Acceptable
Acceptable
Magnesium
mg1L
NE
Acceptable
Acceptable
Acceptable
Manganese
ltS1L
50
Acceptable
Acceptable
Acceptable
Mercury
1
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Methane
Molybdenum
µg/L
_
10 I! I51 _ In
1 _ I _ I 716
6.LS6 _
8.837_I^_2.R
NE
Acceptable
Acceptable
Acceptable
Nickel
Nitrate +Nitrite
IL91L
m-N/L
100
Acceptable
Acceptable
Acceptable
It-
Acceptable
Acceptable
Acceptable
Potassium
mg/L
5
g
_U.u�
s
NE
Acceptable
Acceptable
Acceptable
Selenium
9911.
1
1
1
20
Acceptable
Acceptable
Acceptable
Sodium
mg/L
6.139
4.41
7.42
NE
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Strontium
36.71
56.14
107.1
Sulfate
mg/L
1.169
10
15.1
250
Acceptable
Acceptable
Acceptable
Sulfide
mg/L
0.1
0A
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
mg/L
75A7
70.98
120
500
Acceptable
Acceptable
Acceptable
Thallium
0.117
0.063
0.2
0.2
Acceptable
Acceptable
Acceptable
TOC
mg/L
I
I
I
NE
Acceptable
Acceptable
Acceptable
Vanadium
µg/L
1.059
1.095
037
0.3
Not Acceptable
Acceptable
Acceptable
Shallow: normal distribution; 95% UTL with 95% coverage = 0.8.
All vanadium values reported as ", I ugtU'should be omitted from the background dataset because the detection
limit is above the IMAC.
D : vanadium = 3 u L(deep) is identified as an outlier and should be omitted from the damsel.
Zinc
µgfL
15
15.a3
10
1000
Acceptable
Acceptable
Acce table
Radium (Total)
Cill,
2.58
I51
d.l
NE
Acceptable
Acceptable
Acceptable
Uranium (Total
mL
0.0005
Q01g5
0.ODU5
NE
Acce mble
Acceptable
Acceptable
NA - Not Applicable
S.U. - Standard Unit
NO - Not Detected
TOC - Total Organic Carbon
NE - Not Established
TDS - Tom] Dissolved Solids
mg/L - milligrams per liter
µg/mL - microgams per milliliter
pCi/L - picocuries per liter
µg/L - micrograms per liter
Radium (Total) - Radium-226 and Radium-228 combined
Uranium (Total) - Uranium-233, Umnium-234, Umnium-236, and Umnium-238 combined
-The 15A NCAC 02L Standard is 10 mg/L for Nitrate and I mg/L for Nitrite (added for a total of 11 mg/L)

James E. Rogers Energy Complex - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calculated
PR r�•s
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not Acceptable)
Comments
H
S.U.
4.7 - 6.7
NE
Acceptable
Aluminum
mgfkg
36464
NE
Acceptable
Antimony
mgfkg
NA
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mgfkg
4.88
5.8
Acceptable
Barium
m
233
580
Acceptable
Beryllium
m
_ _ 38.9
63
Acceptable
Boron
mg/kg
1.92
45
Acceptable
Cadmium
mgfkg
ND
3
Not Acceptable
Use PSRG of 3. To be revised when valid data set is available.
Calcium
m
_ 304
NE
Acceptable
Chloride
m
ND
NE
Acceptable
Chromium
mg/kg
_ 109 _
3.8
Acceptable
Cobalt
m
_ 59.5
0.9
Not Acceptable
Normal distribution at 5% significance level; 95% UTL with 95% coverage = 43.
Copper
mg/kg
34.7
700
Acceptable
Iron
m
75162
150
Acceptable
Lead
mvJkQ
38.1
270
Acceptable
Magnesium
mgfkg
2.1562
NE
Acceptable
Manganese
m
1518
65
Not Acceptable
Gamma distribution at 5% significance level; 95% UTL WH and H W averse with 95% coverage = 1421.
Mercury
mg/kg
0.016
1 -
Acceptable
Molybdenum
mgfkg
U.97
NE
Acceptable
Nickel
m
66.2
130
Acceptable
Nitrate (as N)
m&g
ND
NE
Acceptable
Potassium
m
18460
NE
Acceptable
Selenium
mgfkg
_ 12 _
2.1
Not Acceptable
N < 10 so use maximum = 8.3
Sodium
mg/kg
194
NE
Acceptable
Strontium
mg/kg
14.1
NE
Acceptable
Sulfate
mg/kg
ND
250
Acceptable
Thallium
m
_ _ N n _
0.28
Not Acceptable
Use PSRG of 0.28. To be revised when valid data set is available.
Vanadium
m
142
6
Acceptable
Zinc
m
214
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

Dan River Combinded Cycle Station- Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PBTVs
Flow Unit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Deep
Bedrock
Shallow
Deep
Bedrock
H
S.U.
4.0-7.1
5.3-6.8
6.7-8.4
6.5-8.5
Acceptable
Acceptable
Acceptable
Alkalinity
mg/L
77.7
168
236
NE
Acceptable
Acceptable
Acceptable
Aluminum
118
113
100
NE
Acce table
Acceptable
Acceptable
Antimony
g/L
0.5
0.5
0.5
1
Acceptable
Acceptable
Acceptable
Arsenic
g/L
0.5
1.62
0.833
10
Acceptable
Acceptable
Acceptable
Barium
L
19
80.4
128
700
Acceptable
Acceptable
Acceptable
Beryllium
µg/L
0.429
0.0772
0.0625
4
Acceptable
Acceptable
Acceptable
Bicarbonate
mg/L
77.7
168
233
NE
Acceptable
Acceptable
Acceptable
Boron
50
50
50.9
700
Acceptable
Acceptable
Acceptable
Cadmium
L
0.08
0.08
0.08
2
Acceptable
Acceptable
Acceptable
Calcium
mg/L
19A
59
59.1
NE
Acceptable
Acceptable
Acceptable
Carbonate
mg/L
5
5
5
NE
Acceptable
Acceptable
Acceptable
Chloride
mg/L
7.3
6.8
7.1
250
Acceptable
Acceptable
Acceptable
Chromium I)
L
0.58
1.24
0.15
NA
Ace table
Acceptable
Acceptable
Chromium
µg/L
1.26
3.42
8.31
10
Acce table
Acceptable
Acceptable
-
Cobalt
µ L
2A
0.85
1
1
Ace table
Acceptable
Acceptable
Copper
I ggfL
2.67
2.29
13
1000
Acceptable
Acceptable
Acceptable
Iron
µg/L
152
2130
1400
300
Acceptable
Not Acceptable
Acceptable
Please explain why two distinguished subgroups of population exist and whether they should be
grouped together should also be evaluated.
Lead
AWL
0.1
0.13
1.4
15
Ace table
Acceptable
Acceptable
Magnesium
mgIL
12.2
15.9
20.7
NE
Acceptable
Acceptable
Acceptable
Manganese
81.2
552
38.9
50
Ace table
Acceptable
Acceptable
Mercury
AWL
0.2
0.2
0.2
1
Acceptable
Acceptable
Acceptable
Methane
pg/L
10
10
233
NE
Acceptable
Acceptable
Acceptable
Molybdenum
0.5
0.927
1.4
NE
Acceptable
Acceptable
Acceptable
Nickel
2.88
3.65
19.2
100
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
to -N/L
0.53
0.349
0.074
11•
Acceptable
Acce table
Acceptable
Potassium
mg/L
5
5
5
NE
Accept le
Acceptable
Acceptable
Selenium
0.5
0.5
1 0.5
20
Acceptable
Acceptable
Acceptable
Sodium
mg/L
17.3
17.8
19.2
NE
Acceptable
Acceptable
Acceptable
Strontium
P&I
211
481
2120
NE
Acceptable
Acceptable
Acceptable
Sulfate
mg/L
36.7
36.7
11.3
250
Acceptable
Acceptable
Acceptable
Sulfide
mg/L
0.1
0.1
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
m L
187
244
284
500
Ace table
Acceptable
Acceptable
Thallium
µg/L
0.1
0.1
0.1
0.2
Ace table
Acceptable
Acc table
TOC
mg/L
1
1
1
NE
Ac table
Acceptable
Acce table
Vanadium
L
0.413
0.645
2.52
0.3
Ace table
Acceptable
Acceptable
Zinc
pg/L
46.3
10
16
1000
Acce table
Acce table
Acceptable
Radium (Total)
pCi/L
1.45
1.38
1.63
NE
Acceptable
Acceptable
Acceptable
Uranium Total
mL
0.005
0.00106
1 0.002
NE
Ace table
Acce [able
-Acce table
NA - Not Applicable
S.U. - Standard Unit
ND - Not Detected
TOC- Total Organic Carbon
NE - Not Established
TDS - Total Dissolved Solids
mg/L -milligrams per liter
µg/mL - micrograms per milliliter
pCi/L- picocuries per liter
pg/L- micrograms per liter
Radium (Total) - Radium-226 and Radium-228 combined
Uranium (Total) - Uranium-233, Uranium-234, Uranium-236, and Uranium-238 combined
*The 15A NCAC 02L Standard is 10 mg/L for Nitrate and 1 mg/L for Nitrite (added for a total of 11 mg/L)

Dan River Combined Cycle Station - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calculated
PBTVs
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
pH
S.U.
2.3 - 9.4
NE
Acceptable
Aluminum
mg/kg
34500
NE
Acceptable
Antimony
mg/kg
NA
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mg/kg
12.37
5.8
Acceptable
Barium
mg/kg
132.9
580
Acceptable
Beryllium
m
3.313
63
Acceptable
Boron
mg/kg
ND
45
Acceptable
Cadmium
mg/kg
ND
3
Acceptable
Calcium
mg/kg
2276
NE
Acceptable
Chloride
mg/kg
ND
NE
Acceptable
Chromium
mg/kg
44.54
3.8
Acceptable
Cobalt
mg/kg
29.23
0.9
Acceptable
Copper
mg/kg
87.34
700
Acceptable
Iron
mg/kg
68009
150
Acceptable
Lead
mg/kg
30.94
270
Acceptable
Magnesium
mg/kg
12119
NE
Acceptable
Manganese
mg/kg
802
65
Acceptable
Mercury
mg/kg
0.04
1
Acceptable
Molybdenum
mg/kg
ND
NE
Acceptable
Nickel
mg/kg
45.58
130
Acceptable
Nitrate (as N)
mg/kg
ND
NE
Acceptable
Potassium
mg/kg
3160
NE
Acceptable
Selenium
mg/kg
NA
2.1
Not Acceptable
Use PSRG of 2.1. To be revised when valid data set is available.
Sodium
mg/kg
ND
NE
Acceptable
Strontium
mg/kg
84.96
NE
Acceptable
Sulfate
mg/kg
ND
250
Acceptable
Thallium
mg/kg
NA
0.28
Not Acceptable
Use PSRG of 0.28. To be revised when valid data set is available.
Vanadium
mg/kg
58.73
6
Acc table
Zinc
m
191.8
1200
Acceptable
NA - Not applicable (dataset contains Zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

H. F. Lee Energy Complex - Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PB"1"%'s
Flow Unit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not
Comments
Flow Unit
S6allosa. (alleFesur
Shallow
Cape Fear
H
S.U.
3.4-6.8 5.3-8.3
73 _ 219
6.5-8.5
Acceptable
Acceptable
Alkalinity
L
NE
Acceptable
Acceptable
Aluminum
1059 �- _ 264
NE
Acceptable
Acceptable
Antimony
µg/L
I I_ 1
I
Acceptable
Acceptable
Arsenic
1 _ _'� _ _ 1
o41 _"_ 342
1 1
10
Acceptable
Acceptable
Barium
700
Acceptable
Acceptable
Beryllium
4
Acceptable
Acceptable
Bicarbonate
mg/L
73.9
219
NE
Acceptable
Acceptable
Boron
50
700
Acceptable
Acceptable
Cadmium
µg/L
1
_256
1
2
Acceptable
Acceptable
Calcium
L
11.2 "
30.8
NE
Acceptable
Acceptable
Carbonate
m
5
5
NE
Acceptable
Acceptable
Chloride
M91L
19
72
250
Acceptable
Acceptable
Chromiurn(VI)
µg/L
0.354
0.15
NA
Acceptable
Acceptable
Chromium
I
1
10
Acceptable
Acceptable
Cobalt
13.7
8.07
1
Acceptable
Not Acce table
Cape Fear Aquifer PBTV -1 (99%ile)
Copper
4.39
1
1000
Acceptable
Acceptable
Iron
µg/L
6320
11600
300
Not Acceptable
Acceptable
SurficialAquifer PBTV-413.8(99%ile)
Lead
Z.61
/
15
Acceptable
Acceptable
Magnesium
m
6.55
6.94
NE
Acceptable
Acceptable
Manganese
µ
1140
111"
50
Not Acceptable
Acceptable
SurficialAquifer PBTV - 838 (99%ile)
Mercury
µg/L
0.05
0.05
1
Acceptable
Acceptable
Methane
16.7
7701
NE
Acceptable
Acceptable
Molybdenum
1
10.9
NE
Acceptable
Acceptable
Nickel
pg/L
9.81
15.3
100
Acceptable
Acceptable
Nitrate + Nitrite
m -N/L
II
0.953_
If*
Acceptable
Acceptable
Potassium
mg/L
4,95
5.2
NE
Acceptable
Acceptable
Selenium
1
1
20
Acceptable
Acceptable
Sodiwn
mg/L
11.5
102
NE
Acceptable
Acceptable
Strontium
119
13.1
NE
Acceptable
Acceptable
Sulfate
mg/L
54.7
23
250
Acceptable
Acceptable
Sulfide
mg/L
0.1 _
0.1
NE
Acceptable
Acceptable
TDS
L
163
385
500
Acceptable
Acceptable
Thallium
µg/L
0.2 �_ 0.2
0.2
NE
Acceptable
Acceptable
Acceptable
Acceptable
MOLL L
_
15 - - 1.7
n.411 2.18_
20+ _ R
2? a _ 3.01
n.002 iii 0.00114
Vanadium
0.3
Acce table
Not Acceptable
Cape Fear Aquifer PBTV - 0.3 (99%ile)
Zinc
L
1000
Acceptable
Acceptable
Radium (Totall
pCVL
NE
Acceptable
Acceptable
Uranium (Total)
mL
NE
Acceptable
Acceptable
NA - Not Applicable
ND - Not Detected
NE - Not Established
mg/L - milligrams per liter
pCYL - pic.enas per liter
Radium (Total) - Radium-226 and Radian-228 combined
'The 15A NCAC 02L Standard is 10 mg/L for Nitrate and 1 mail, for Nitrite (added for a total of I I my L)
S.U. - Standard Unit
TOC - Total Ortgnic Carbon
TDS - Total Dissolved Solids
µg/ml. - micrograms per milliliter
µg/L - micrograms per liter
Uranium (Total) - Uranium-233, Uranium-234, Umnium-236, and Ummum-238 combined

H. F. Lee Energy Com lex - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calculated
PB'f 4 s
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acce table
Comments
H
S.U.
NE
Duke Energy/Synterra collected one soil sample that fit the criteria for background sampling prior to this submission.
Per Ryan Czop additional soil analyses and PBTV will be forthcoming in early October. To be revised when valid data set is
available.
Aluminum
mg/kg
NE
Antimony
m
0.9
Arsenic
mg/kg
5.8
Barium
m
580
Beryllium
mg/kg
63
Boron
m k
45
Cadmium
mg/kg
3
Calcium
mg/kg
NE
Chloride
mg/kg
NE
Chromium
mg/kg
3.8
Cobalt
mg/kg
0.9
Copper
m
700
Iron
mg/kg
150
Lead
mg/kg
270
Magnesium
mg/kg
NE
Manganese
mglkg
65
Mercury
mg/kg
I
Molybdenum
mg/kg
NE
Nickel
mg/kg
130
Nitrate as N)
m
NE
Potassium
mg/kg
NE
Selenium
mg/kg
2.1
Sodium
mg/kg
NE
Strontium
mg/kg
NE
Sulfate
mg/kg
250
Thallium
mg/kg
0.28
Vanadium
m
6
Zinc
m g
1200
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mgtkg - milligrams per kilogram
S.U. - Standard Unit

Marshall
Steam Station - Groundwater Provisional Back round Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PBTVs
Flow [;nit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Deep
Bedrock
Shallow
Deep
Bedrock
H
S.U.
4.8 - 6.1
5.8 - 7.9
5.9 - 7.1
6.5-8.5
Acceptable
Acceptable
Acceptable
Alkalinity
m
29.7
237.502
108
NE
Acceptable
Acceptable
Acceptable
Aluminum
925.6
190.1
463
NE
Not Acceptable
Acceptable
Acceptable
Shallow - Removed 1,200 u L Gamma UTL - 612.4 u . Please revise accordingly.
Antimony
1
11.5
1
1
Acceptable
Acceptable
Acceptable
Arsenic
11.219
1.5
1
10
Acceptable
Acceptable
Acceptable
Barium
148
45.53
66.9
700
1 Acceptable
Acceptable
Acceptable
Beryllium
PgL
0.374
0.0759
t
4
Acceptable
Acceptable
Acceptable
Bicarbonate
mg/L
30.8
237.502
108
NE
Not Acceptable
Acceptable
Acceptable
Shallow - Removed 186 ug/L Normal UTL - 36.93 mg/L. Duke should verify value removed to ensure value
was in proper units revise if needed.
Boron
L
50
50
50
700
Acceptable
Acceptable
Acceptable
Cadmium
0.08
1
2
Acceptable
Acceptable
Acceptable
Calcium
m L
6.115
_0.08
88.033
13.7
NE
Acceptable
Acceptable
Acceptable
Carbonate
m
5
5
5
NE
Acceptable
Acceptable
Acceptable
Chloride
mgIL
4.3
5.186
2.7
250
Acceptable
Acceptable
Acceptable
Chromium(VI)
µg/L
1.742
1.48
4.818
NA
Not Acceptable
Not Acceptable
Not Accetpable
Duke should verify values established for Chromium (VI) were done so using Chromium (VI) data and not
total Chromium.
Chromium
µg/L
4.822
2.545
5
IO
Not Acceptable
Not Acceptable
Not Accetpable
Duke should verify values established for Chromium were done so using Chromium data and not total
Chromium (VI).
Cobalt
3.7
2.4
3.802
1
Acceptable
Acceptable
Acceptable
Copper
1191L
3.131
3.7M
5
1000
Acceptable
Acceptable
Acceptable
Iron
AWL
817.5
336.6
675.8
300
Acceptable
Acceptable
Acceptable
Lead
0.738
0.348
1
15
Acceptable
Acceptable
Acce table
Magnesium
m
1.517
8.723
13.6
NE
Acceptable
Acceptable
Acc table
Man anew
82
187.1
310
50
Acceptable
Acceptable
Acceptable
Page 1 of 2

Marshall Steam Station - Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PBTVs
Flow Unit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Deer
Bedrock
Shallow
Deep
Bedrock
Mercury
0.05
0.2
0.05
1
Not Acceptable
Acceptable
Not Acceptable
Shallow, deep, and bedrock Non -Par. UTL - 0.2 u
Methane
to
10
16.4
NE
Acceptable
Acceptable
Acceptable
Molybdenum
AgIL
0.684
9
4.262
NE.
Acceptable
Acceptable
Acceptable
Nickel
ggfL
5.944
7.325
5
100
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
m -N/L
1.6
0.8946
0.38118
ll*
Acceptable
Acceptable
Acceptable
Potassium
m
5
4.453
8.19
NE
Acceptable
Acceptable
Acceptable
Selenium
0.5
0.5
1
20
Acceptable
Acceptable
Acceptable
Sodium
mg/L
9.753
39.917
14
NE
Acceptable
Not Acceptable
Acceptable
Deep - Removed 7,550 ug/L Gamma UTL - 42.61 mg/L. Duke should verify value removed to ensure value
was in proper units revise if needed.
Strontium
197.1
548.2
195
NE
Acceptable
Acceptable
Acceptable
Sulfate
m
1.9
50.259
14.4
250
Acceptable
Acceptable
Acceptable
Sulfide
m
0.1
0.1
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
mg/L
79.833
257.046
177
500
Acceptable
Not Acceptable
Acceptable
Deep Normal UTL - 221.1 ug/L. Please revise accordingly.
Thallium
0.2
0.1
0.2
0.2
Acceptable
Acceptable
Acceptable
TOC
mg/L
1 1
4
1
NE
Acceptable
Acceptable
Acceptable
Vanadium
99fL
6.884
4.373
22,93
0.3
Acceptable
Acceptable
Acceptable
Zinc
t5.93
31.05
10
1000
Acc table
Acce table
Acc table
Radium (Total)
Ci/L
U.47
NA
1.884
NE
Acc table
Acc table
Acc table
Uranium Total)
mL
0.0005
ti N
0.0005
NE
Acceptable
Acceptable
Acceptable
NA - Not Applicable
ND - Not Detected
NE - Not Established
S.U. - Standard Unit
TOC - Total Organic Carbon
TDS - Total Dissolved Solids
mg/L - milligrams per liter µg/mL - micrograms per milliliter
pCi/L - picocuries per liter µg/L - micrograms per liter
Radium (Total) - Radium-226 and Radium-228 combined Uranium (Total) - Uranium-233, Uranium-234, Umnium-236, and Uranium-238 combined
*The 15A NCAC 02L Standard is 10 mg/L for Nitrate and 1 mg/L for Nitrite (added for a total of I 1 mg(L)
Page 2 of 2

Marshall Steam Station - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energ}
Calculated
PBTVs
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
4.1-6.7
NE
Acceptable
Aluminum
mg/kg
25978
NE
Acceptable
Antimony
mg/kg
NA
0.9
Not Acceptable
Use PSRG of 0.9. To be revised when valid data set is available.
Arsenic
mg/kg
3.7
5.8
Acceptable
Only 3 valid samples in data set.
Barium
mg/kg
312.9
580
Acceptable
Beryllium
m
2.8
63
Not Acceptable
Gamma UTL - 4.52 mg/kg
Boron
mg/kg
56.3
45
Acceptable
Cadmium
mgfkg
NO
3
Acceptable
Calcium
mgfkg
718
NE
Not Acceptable
Normal UTL - 999.1 mg/kg.
Chloride
mg/kg
NO
NE
Acceptable
Chromium
mg/kg
24.64
3.8
Acceptable
Cobalt
mg/kg
46.5
0.9
Acceptable
Copper
m
88.76
700
Acceptable
Iron
mg/kg
78988
150
Acceptable
Lead
m
_ 15.36
270
Acceptable
Magnesium
mg/kg
_
33058
NE
Not Acceptable -
Normal UTL - 14,554 m
Manganese
m
1748
65
Acceptable
Mercury
mg/kg
(1.07778
1
Acceptable
Molybdenum
m
_ 111)
NE
Acceptable
Nickel
mglkg
15.85 _
130
Acceptable
Nitrate as N)
m
NO
�21444
NE
Acceptable
Potassium
mgfkg
NE
Not Acceptable
Normal UTL - 21,063.5 mg/kg.
Selenium
mg/kg
NA
2.1
Not Acceptable
Use PSRG of 2.1. To be revised when valid data set is available.
Sodium
mg/kg
NO
NE
Acceptable
Strontium
mgtkg
9.869
NE
Acceptable
Sulfate
mg/kg
ND
NE
Acceptable
Thallium
mgIkg
N:%
0.28
Not Ace e table
jUse PSRG of 0.28. To be revised when valid data set is available.
Vanadium
mg/kg
2026.
6
Acceptable
Zinc
mg/kg
105.4
1200
Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

L. V. Sutton Energy Complex- Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy Calculated PBT\'s
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Ace e table)
Comments
Flow Unit
Flow Unit
Surficial
t pier,
Surilcld Pee Dee
Lower 1'over
Pee flee
Lmvrer
Surficial
Upper
Surficial
Lower
Pee Dee
Upper
Pee Dec
Lower
H
S.U.
3.94 5
__ 5
95a
I
1 J::i,17
4.9 - 7.4 L R.2 - 8.9
9 - 9,7
6.5-8.5
Acceptable
Acceptable
Not Acceptable
Not Acce table
Insufficient datasets for the Upper and Lower Pee Dee. Additional samples am needed for valid
statistical analysis. To be revised when valid data set is available.
Alkalinity
mg/L
171 1 410
7. _ 593
I
464
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Aluminum
µg/L
73
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Antimony
µg/L
1
1
1
10
Acceptable
Acceptable
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Arsenic
3
Barium
Beryllium
g/L
µ
45
I
_
17
I 1
27
1
391
3520
1
700
4
NE
700
2
Acceptable
Ace table
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acce table
Not Acce table
Not Acee table
Not Acceptable
Bicarbonate
mg/L
5
_ _
I'1 402
Boron
50
_
50 3010
Cadmium
1
_
1 1
Calcium
mg/L
0.996
22.6
9.47
48
NE
NE
Acceptable
Acceptable
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Carbonate
m L
S
5 _ _20
_ _21.o_ 68_0
Chloride
mg/L
4.73
1200
250
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Chromium (VI)
µgH-
0.03
0.11 0.26
0.1
NA
Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
Surficial Lower: Insufficient data set for hex chrome. To be revised when valid data set is available.
insufficient datasets for the Upper and Lower Pee Dec. Additional samples are needed for valid
statistical anaysis. To be revised when valid data set is available.
Chromium
L
1
4
I
3
2
1
1
10
Acc [able
Acceptable
Not Acceptable
Not Acceptable
Insufficient damsels for the Upper and Lower Pee Dee. Additional samples are needed for valid
statistical anaysia To be revised when valid data se[ is available.
Cobalt
1191L
1
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Copper
µg/L
1
I
_
1
1
1000
Acceptable
Acceptable
I Not Acceptable
Not Acceptable
Iron
g/L
1494
13416
336
102
300
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Lead
1
1
1
1
15
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Magnesium
m
0.589
W
13.5
13.7 .
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Manganese
38
746
63
5
50
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Mercury
L
I 0.05
0.05
0.05
0.05
1
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Methane
µg/L
25.8
36.1
121
19.6
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Molybdenum
µ
1
1
20.7
16.1
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Nickel
L
1
I 1
1
3.29
100
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Nitrate+ Nitrite
Potassium
Selenium
mg -NH-
mg/L
0.167
0.738
1
0.098
4.97
I
0.01 0.011
211.5 _ 48
I 5
11 a
NE
20
Acceptable
Acceptable
Acceptable
I Acceptable
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Not Acceptable
I Not Acceptable
Not Acceptable
Not Acceptable
Sodium
mg/L
_
3 _ 18,5 !
8 16-
15.6 16
0.1 _ r 0.1
25 210
_
584 _ 939
232 329
..20 SSU
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Strontium
µ L
NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Sulfate
mg/L
250
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Sulfide
m L
1 0.14
1.8
1 NE
Acceptable
Acceptable
Not Acceptable
Not Acceptable
TDS
mg/L
1700
1800
500
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Thallium
p9fL
0.2
0.2
0.2
0.2
0.2
Acceptable
Acceptable
Not Acceptable
Not Acceptable
TOC
mg/L
0.692
6.7
33
6.6
NE
I Acceptable
Acceptable
I Not Acceptable
Not Acceptable
Vanadium
0.621
1.68
1.88
0.481
0.3
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Zinc
µg/L
5
13
_
5
6
1000
Acceptable
Acceptable
Not Acceptable
Not Acceptable
Radium (Total)
Uranium (Total)
Ci/L
/ml,
2.75
0.00035
5.32
030a14
2 4�5.5.1
0.00153
0.00077
NE
NE
Acceptable
Acce table
Acceptable
Acce table
Not Acceptable
Not Aeee table
Not Acce table
Not Acce table
NA- Not Applicable
NO -Not Delected
NE -Not Established
mg/L - milligrams per liter
pCUL - picocuries per liter
Radium (Total) - Radiurn-226 and Radium--228 combined
'The 15A NCAC 02L Standard is 10 mg/L for Nitrate and 1 mg/L for Nitrite (added for a total of I I mg/L)
S.U. -Standard Unit
TOC - Total Organic Carbon
IDS - Total Dissolved Solids
pg/mL - micrograms per milliliter
jig - micrograms per liter
Uraniurn (TOW) - Ursedura-233, Uranimn-234, Uranimn-236, and Umnimn-238 combined

L. V. Sutton Energy Complex - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
�alrulated
PR.I,N s
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
NE
Only two valid samples, therefore dataset is insufficient. Additional samples planned for collection. To be revised when valid data set is available.
Aluminum
mg/kg
_
NE
Antimony
mgIkg
0.9
Arsenic
m
5.8
Barium
m
580
Beryllium
mg/kg
63
Boron
mg/kg
45
Cadmium
mg/kg
3
Calcium
m
NE
Chloride
mgtkg
NE
Chromium
m
3.8
Cobalt
mg/kg
0.9
Copper
mg/kg
700
Iron
m
150
Lead
m
270
Magnesium
m
NE
Manganese
mglkg
65
Mercury
mgfkg
1
Molybdenum
mg/kg
NE
Nickel
mg/kg
jja.
130
NE
Nitrate (as N)
mg/kg
Potassium
mg/kg
NE
Selenium
mg/kg
2.1
Sodium
mg/kg
NE
Strontium
mg/kgmg1kg
NE
Sulfate
mgfkg
250
Thallium
mg/kg
0.28
Vanadium
m
6
Zinc
mglkg
1200
NA -Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligatns per kilogram
S-U. - Standard Unit

W. H. Weatherspoon Power Plant- Groundwater Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy ('alculated PH I V%
llnw Cnit
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Surficial
1'urktown
Pee Dee
Surficial
Yorktown
Pee Dee
H
S.U.
3.21-6.87
5.5.5.7
6.9-8.3
6.5-8.5
Acceptable
Acceptable
Acceptable
Alkalinity
mg/L
36.5
_17.4
89
NE
Acceptable
Acceptable
Acceptable
Aluminum
1191L
_
1460
492
66
NE
Acceptable
Acceptable
Acceptable
Antimony
L
♦D
1
1
1
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value, 1 L.
Arsenic
L
1.35
1
1
10
Acceptable
Acceptable
Acceptable
Barium
31.9
21
56
700
Acceptable
Acceptable
Acceptable
Beryllium
991L
ND
1
1
4
Not Acceptable
Acceptable
Acceptable
ISurficial should be a numeric value, 1 L.
Bicarbonate
mgfL
36.5
17.4
89
NE
Acceptable
Acceptable
Acceptable
Boron
W111,
ND
50
50
700
Not Acceptable
Acceptable
Acceptable
JSurficial should be a numeric value, I L.
Cadmium
L
ND
1
1
2
Not Acceptable
Acceptable
Acceptable
Surlicial should be a numeric value, I
Calcium
mgfL
14.5
7.92
M
NE
Acceptable
Acceptable
Acceptable
Carbonate
mg/L
ND
5
10
NE
Not Acceptable
Acceptable
Not Acceptable
Surficial should be a numeric value, 5 mg/L.
MDL for Pee Dee was 5 m l 5z 10 mg/1 only 3z .
Chloride
m
22.2
10
3.4
250
Acceptable
Acceptable
Acceptable
Chromium (VI)
uWL
01147
0.84
0.2
NA
Acceptable
Acceptable
Acceptable
Chromium
uWL
1.63
1 ?4
1
10
Acceptable
Acceptable
Acceptable
Cobalt
L
_
\ D
1
1
20'u
I
t 1
t I550
I
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value, I L.
Copper
L
ND
132_31
1000
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value I
Iron
300
Not Acceptable
Acceptable
Acceptable
Surficial calculated to be 9422
Lead
SU
1
1
15
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value, 1 L.
Magnesium
mg/L
I.39 0.487 _ a 1.11 _
39 _ 20 r 41
ti1105 005
NE
Acceptable
Acceptable
Acceptable
Manganese
50
Acceptable
Acceptable
Acceptable
Mercury
8&1
1
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value, 0.05
Methane
L
41'. iOxU 2J8
NE
Acceptable
Acceptable
Acceptable
Molybdenum
- j I 1
_ �D _ - - I _ 1
2.09 _ -0-11-1 11.01
1.16 _ O'shS L62
NE
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value 1
Nickel
100
Not Acceptable
Acceptable
Acceptable
Surficial should be a numeric value, 1
Nitrate + Nitrite
mg -NIL
it-
Acceptable
Acceptable
Acceptable
Potassium
mg/L
NE
Acceptable
Acceptable
Acceptable
Selenium
ND
I I
20
Not Acceptable
Acceptable
Acceptable
IStaficial should be a numeric value, 1
Section
m
13
xx
6 _ 272 _
41 164
1.l a 0.24
0.1 b 1 _ _
75 130_
NE
Acceptable
Acceptable
Ace table
Strontium
AWL
NE
Acceptable
Acceptable
Acceptable
Sulfate
IUZIL
13.7
250
Acceptable
Acceptable
Ace ble
Sulfide
ingfL
0.29
NE
Acceptable
Acceptable
Ace ble
TDS
mg/L
90 .3
500
Acceptable
Acceptable
Ace ble
Thallium
L
ND
0.2 0 2
0.2
Not Acceptable
Acceptable
Ace ble
Surficial should be a numeric value, 0.2 µg/L.
TOC
mg/L
7.9
3.5
1.1
NE
Acceptable
Acceptable
Ace table
Vanadium
L
4.65
E.61
0.32
0.3
Not Acceptable
Acceptable
Ace ble
Surficial calculated to be 4.2 L.
Zinc
µ
10
5
5
1000
Acceptable
Acceptable
Acc table
Radium Total
Ci/L
7.09
S.4
3.55
NE
Not Acceptable
Acceptable
A. ptable
JSurficial calculated to be 6.463 i/L.
Uranium (Total)
ggfmL
0.0006
0.001
1 0.6004
NE
Acceptable
Acc table
Acceptable
NA -Not Applicable
ND -Not Detected
NE - Not Established
mg/L -millibar. per Ike,
pCi/L - picocmies per liter
Radium (Total) - Radiun-226 and Radium-228 combined
-The ISA NCAC 02L Standard m 10 mg/L for Nitrate and 1 ,11, for Nitrite (added for a total of I I mg/L)
S.U.-Standard Unit
TUC - Tom[ Organic Carbon
TDS - Total Dissolved Sell&
µg/snL - micrograms per milli@er
µgo - micrograms per liter
Umoiam (Toml) - Uranium-233, Uranium-234, Umnimn-236, and Ummum-238 combined

W. H. Weatherspoon Power Plant - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Energy
Calculated
PB -f%s
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Accepts le)-
Comments
H
S.U.
NE
Insufficient dataset. Additional data to be provided by Duke Energy. To be revised when valid data set is available.
Aluminum
mg/kg
NE
Antimony
mg/kg
0.9
Arsenic
m
5.8
Barium-
m
580
Beryllium
- mg/kg
63
Boron
mg/kg
45
Cadmium
m
3
Calcium
m
NE
Chloride
mglkg
NE
Chromium
mg/kg
3.8
Cobalt
mg/kg
- - - -_
0.9
Copper
mg/kg
700
Iron
m
_—
150
Lead
m
270
Magnesium
m
_ _ _ _
NE
Manganese
mg/kg
65
Mercury
mg/kg
_
1
Molybdenum
mg/kg
NE
Nickel
mg/kg
130
Nitrate (as N)
mg/kg
NE
Potassium
m /k
NE
Selenium
mg/kg
2.1
Sodium
m /kg
NE
Strontium
m
NE
Sulfate
m
250
Thallium
m g
0.28
Vanadium
m /kg
6
Zinc
m o
1200
NA- Not applicable (dataset contains zero valid samples)
ND -Non-Detect
NE - Not Established
mgtkg - milligrams per kilogram
S.U. - Standard Unit

Water Resources .,
Environmental Quality
April 27, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: Corrective Action Plan Content for Duke Energy Coal Ash Facilities
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
Attached is guidance related to technical content and format the Department requests be followed
for the upcoming Corrective Action Plan (CAP) Update documents associated with the Duke
Energy coal ash facilities. Please note that pursuant to Title 15A North Carolina Administrative
Code, Subchapter 02L (15A NCAC 02L) Rule .011l(a), any person subject to the requirements
for corrective action specified in 15A NCAC 02L .0106 shall submit to the Director written reports
in such detail as specified by the Director. The CAP shall contain sufficient information for the
Secretary to evaluate the plans in accordance with the specifications in 15A NCAC 02L .0106(i).
The CAP content for Duke Energy coal ash facilities is provided in Attachment 1. If you have any
questions, please feel free to contact me at [phone] or Steve Lanter in the Central Office at
[phone].
Sincerely,
S. Jay 2iinynerman, P.G.
Division of Water Resources
Attachments: Attachment 1 Corrective Action Plan Content for Duke Energy Coal Ash Facilities
cc: WQROS Regional Office Supervisors
WQROS Central File Copy
<-- "Nothing Cornpaires n�,
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional Operations Section
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

CORRECTIVE ACTION PLAN CONTENT FOR
DUKE ENERGY COAL ASH FACILITIES
APRIL 27, 2018
Best professional judgement must be applied to generate the Corrective Action Plan (CAP) documents. In
general, all items described in this guidance are expected to be addressed in the CAPs. Duke Energy must
provide justification/rationale concerning any information not provided as stipulated in this guidance.
1 INTRODUCTION
A. Background
B. Purpose and Scope
C. Regulatory basis for closure and corrective action (note that "closure" refers here to source
control and (or) source excavation in accordance with Coal Ash Management Act (CAMA) and
(or) 15A NCAC 02L (02L) .0106, while "corrective action", "remediation", or "remedy" refer
here to the treatment of groundwater contamination)
a. CAMA requirements
b. 02L requirements, including Notice of Regulatory Requirement dated 8/13/14
c. Other requirements such as court order, Federal requirements, etc.
D. List of Criteria for Evaluation of Remediation Alternatives as referenced in 02L .0106 (i)
a. Extent of any violations
b. Extent of any threat to human health or safety
c. Extent of damage or potential adverse effects to the environment
d. Technology available to accomplish restoration
e. Potential for degradation of the contaminants in the environment
f. Time and costs estimated to achieve groundwater quality restoration
g. Public and economic benefits to be derived from groundwater quality restoration.
E. Facility Description (brief summary from Comprehensive Site Assessment [CSA))
a. Location and history of land use (to include period prior to Duke ownership)
b. Operations and waste streams (coal and non -coal)
c. Overview of existing permits and Special Orders by Consent (National Pollutant
Discharge Elimination System, storm water, sediment and erosion control, etc.)
2. RESPONSE TO COMPREHENSIVE SITE ASSESSMENT UPDATE COMMENTS IN SUPPORT OF CAP
DEVELOPMENT
A. Include the Facility -Specific Comprehensive Site Assessment (CSA) Comment Letter from DEQ
to Duke Energy
B. Duke Energy's response to the DEQ's letter. (NOTE: All deficiencies noted during the
Departments' review of the CSA Update report shall be addressed in the CAP.
1

a. For each comment in the letter, note the specific section(s) of the CAP report that
addresses that comment.
b. If specific sections of the CAP report do not fully or directly address the comment,
provide a separate narrative within the Appendix to address.
3 OVERVIEW OF SOURCE AREAS BEING PROPOSED FOR CORRECTIVE ACTION
Each source area has a unique waste footprint, waste volume and configuration, contaminant
configuration and transport characteristics, and receptors. Consequently, each source area will
potentially need to be remediated in a unique way. For purposes of remediation design and
approval, each source area should be addressed separately as described in this document.
Arranging the report in this way will support an organized, orderly, and efficient review of the
proposed remedy. For facilities in which only one source area is defined (or multiple source areas
that can be combined into a single largersource area), the CAP sections which pertain to additional
source areas would not be needed. It is not the intent to require a separate CAP Report submittal
for each source area, rather a single facility CAP (Cliffside, e.g.) submittal may contain the contents
of multiple source areas.
A. Small scale map showing the waste boundary of each source area proposed for corrective
action
a. For cases in which more than one smaller source area is being combined as one larger
source area, show each "sub area" on the waste boundary map (i.e. show the waste
boundaries of the individual smaller source areas that are within the larger source
area)
B. For cases in which there are source areas that are not being addressed within the CAP,
provide:
a. Rationale for omission
b. Certification that consensus was reached with the Division on this point.
c. Description that explains the implications for assessment overlap, corrective action
overlap, design, and approval, performance monitoring, potential corrective action
modification and schedule delays.
4 SUMMARY OF BACKGROUND DETERMINATIONS
A. Map showing all background sample locations for all media (groundwater, surface water, soil,
and sediments)
B. Table of background concentrations for soil. Include the corresponding Protection of
Groundwater (POG) Preliminary Soil Remediation Goal (PSRG). Approved Background
Threshold Values (BTVs) for soil and groundwater will be sent to Duke in a letter separate
from the CSA Comments. Please list the approved BTVs.
C. Table of background concentration for groundwater. Include the appropriate 2L/IMAC
Standards. Approved Background Threshold Values (BTVs) for soil and groundwater will be
sent to Duke in a letter separate from the CSA Comments. Please list the approved BTVs.

D. Table of background concentrations for surface water. Include the appropriate 2B/EPA
standards. Present results of all surface water samples and sample events from upstream
locations.
E. Table of background concentrations for sediments. Present results of all sediment samples
and sample events from upstream or otherwise unimpacted sample locations.
5 SUMMARY OF POTENTIAL RECEPTORS
A. Map of all supply wells identified by receptor surveys and per 130A-309.211(cl).
a. Incorporate the most current alternate water supply efforts. That is, indicate which
well owners selected whole -home filtration systems, public water, or opted -out of
any alternate water supply options.
b. Indicate which homes have whole -house filtration systems installed and which homes
have been connected to public water.
c. Indicate if any homes are remaining to be supplied alternate water and the
anticipated supply date.
B. Map of all surface waters (to include wetlands, pond, unnamed tributaries, seeps, etc.) within
%:-mile of the waste boundary of each source area or known extent of contamination
(whichever is greater).
a. Indicate on map all surface waters that are currently permitted as outfalls, along with
the permitted outfall name and NPDES sampling location
b. Indicate on map all surface waters that are currently covered under a Special Order
by Consent.
c. All of the surface waters within 0.5 miles of the perimeter of an impoundment or
known extent of contamination, whichever is greater.
d. For all surface waters shown, indicate stream classification and nearest downstream
supply intake, if applicable
6. SOURCE AREA 1
Contents listed in Section 6 should be prepared separately for each additional source area (i.e.
Source Area 2, Source Area 3, etc., as applicable) in need of remediation. Discussions with the
DWR Regional Office should be initiated prior to preparation of the CAP in order to determine
which individual source areas are appropriate to combine into larger source areas.
Maps prepared for Source Area 1 should be lame scale, typically 1" = 150 to 200 ft and include
topographic contour intervals as agreed upon. However, scale adjustments may be made to
accommodate far reaching receptors; please discuss with Regional Office if this is necessary.
All plan view maps used in the CAP report should be oriented to extend to all identified receptors
(all supply wells and all surface water features), to the extent possible, based on the map scale
and size of source area being depicted.
A. Extent of Contamination
a. Contamination within waste boundary
L Description of waste material and history of placement
3

L7
ii. Specific waste characteristics of source material
iii. Volume and physical horizontal and vertical extent of source material
mapped in plan -view and multiple cross sections
iv. Volume and physical horizontal and vertical extent of saturated source
material mapped in plan -view and multiple cross sections
v. Calculation of specific storage for Source Area 1 (i.e. amount of contaminated
water and COI mass that can be expelled from Source Area 1)
vi. Chemistry within waste boundary
1. Table of analytical results, subdivided as follows:
1. Ash solid phase
2. Ash SPLP
3. Soil (beneath ash)
4. Soil (beneath ash) SPLP
5. Ash pore water
2. Piper diagram(s) for ash pore water if additional pore water data
have become available since the piper diagrams were developed in
the CSA Updates. Otherwise, reference the location of the piper
diagrams that were presented in the CSA Update.
3. Ash pore water isoconcentration maps for each COI in plan -view and
2 or more cross sections
vii. Other source material (Does source contain other waste products besides
CCR? If so, have these been assessed?)
viii. Interim response actions conducted to date to remove or control source
material, if applicable
1. Source control conducted to date or planned to include but not
limited to excavation, dewatering, boundary control measures (e.g.
extraction wells), etc.
2. Source area stabilization conducted to date or planned (e.g. describe
dam safety, flood plain inundation issues, etc.)
Extent of contamination beyond the compliance boundary or waste boundary
(whatever is the point of compliance depending on whether the source area(s) are
covered by a permit or not)
i. Conceptual model of groundwater flow and transport from source to
receptor
1. Local groundwater flow directions and gradients
2. Particle track results, if available
3. Subsurface heterogeneities affecting flow and transport
4. Onsite and offsite pumping influences affecting flow and transport
5. Role of matrix diffusion in/out of bedrock (bedrock porosity) on
contaminant transport
6. Other influences affecting flow and transport
ii. Plan view map showing COI results (bubble inset at each seep location) for
seeps and SWs
iii. Table of analytical sampling results associated specifically with Source Area
1:
I. Soil, as applicable
2. Groundwater (per individual flow regime [e.g. shallow, deep,
bedrock)
rd

3. Seeps (up-, side-, and down -gradient)
4. SW data (up-, side-, and down -gradient)
5. Sediment (up-, side-, and down -gradient)
6. Supply wells (up-, side-, and down -gradient
iv. Piper diagram(s) for each groundwater flow regime, seeps, and all other SWs.
c. COIs
i. List of COls and their maximum concentrations (within and beyond the point
of compliance) that require corrective action based on 2L/IMAC/background
exceedances:
1. Soil
2. Groundwater
3. other media if applicable
ii. List of Cols that this CAP is designed to remedy:
1. Soil
2. Groundwater
3. other media if applicable
d. Isoconcentration maps in plan -view and two or more cross sections for:
L Contaminated soil (defined as any COI in the sample being above POG PSRG
or approved background concentration)
ii. Horizontal and vertical extent of groundwater in need of restoration for each
COI in each groundwater flow regime (shallow, deep, bedrock)
e. Plume Characteristics
L Movement of conservative COls (e.g. boron, sulfate, chloride) from source to
receptor
1. Describe whether plume is moving and (or) expanding
1. Flow path wells and transect wells used to assess plume
behavior
2. Method(s) used to analyze plume behavior (should be
discussed and agreed upon with Regional Office prior to CAP
submittal)
ii. Movement of non -conservative COls (e.g. Fe, Mn, Co, As, TI, etc.)
1. Conceptual model describing local, source area -specific geochemical
controls on COls
1. Basis for conceptual understanding (e.g. batch PHREEQC
results)
2. Representative flow path(s) used to develop and validate
numerical geochemical model
3. Adsorbent data collected along flow path
4. Aqueous speciation data collected along flow path
5. Simulated versus observed COI concentrations at selected
target wells (i.e. how well does geochemical model simulate
local groundwater chemistry?)
2. Variability of pH along representative flow path(s) and along other
flow paths of interest
3. Variability of Eh along representative flow path(s) and along other
flow paths of interest
5

Receptors associated with Source Area 1
a. Map of all surface waters, including wetlands, ponds, unnamed tributaries, seeps, etc.)
associated with Source Area 1 (up-, side-, and downgradient)
L Indicate on map all surface waters that are currently permitted as outfalls, along
with the permitted outfall name and sample location
ii. Indicate on map all surface waters that are currently covered under a Special
Order by Consent
iii. For all surface waters shown, indicate stream classification and nearest
downstream supply intake, if applicable
iv. Indicate on map (footnote) and in report text whether SW samples have been
collected using Division approved protocols ("21_-213" sampling protocols) to
evaluate whether contaminated groundwater is resulting in 213 violations;
include date(s) of 2L-2B sampling and antecedent rainfall
1. If 2L-2B sampling has been conducted, indicate location of all 2L-2B
sample collection points
2. If 2L-2B sampling has been conducted, indicate results of 2B
exceedances on map; also indicate which of those exceedances is a COI
for groundwater for Source Area 1
3. If 2L-2B sampling has not been conducted, explain why and indicate
whether it is being proposed and the proposed sample collection points
b. Map of all supply wells associated with Source Area 1(up-, side-, and down -gradient)
L Indicate on map which well owners did not accept alternative water
ii. Provide analytical results table for the supply wells; indicate in table whether
each well was determined to be impacted or unimpacted by coal ash
iii. For each supply well determined to be unimpacted by coal ash, provide or
reference evidence that substantiates that position, including water level
measurement -based potentiometric mapping, piper diagrams, assessment of
well -specific geochemical conditions that are affecting certain CON, modeling,
etc. The evidence provided or referenced here will be used to review and
accept or deny Duke's determination that a given well is unimpacted by coal
ash.
c. Map of future groundwater use areas associated with Source Area 1
L Indicate on map whether each parcel has or does not have access to alternative
water
ii. Indicate on map whether each parcel was modeled to be impacted or
unimpacted by coal ash now or in the future
C. Human and Ecological Risks
D. Evaluation of Remedial Alternatives
All contents requested below for Section a. should be re )eated for each remedial alternative
that is considered (i.e. Remedial Alternative 2, Remedial Alternative 3, etc.) as directed and
appropriate.
a. Remedial Alternative 1
Problem statement and remediation goals
1. Map of full 3-dimensional extent of contamination that will be
corrected by this alternative
11

2. List of CON within each groundwater flow unit (shallow, deep,
bedrock) that will be corrected by this alternative
3. Concentration clean up goals for each of the CON identified in D. a. i.
2. above
Conceptual model (i.e. simple description explaining how the proposed
source control/removal and corrective action will reduce COI concentrations
and protect human health and environment)
1. COls addressed
2. COls not addressed
3. For each COI not addressed by the proposed corrective action
describe how the constituent will be remedied along with a schedule
for implementation
Predictive modeling
1. Model used to predict movement conservative (sometimes referred
to as leading edge) COIs
2. Model used to predict movement non -conservative CON
3. Simulated versus observed concentrations at selected target wells
(i.e. how well does transport model simulate local groundwater
chemistry?)
4. For "baseline" predictive modeling that shows source removal
(excavation) and other source control measures but no active
groundwater remediation, provide a comprehensive list of all
potential receptors that are or are predicted to be impacted and a
map for each COI showing the maximum predicted radius of travel of
that COI above 2L/IMAC (or background, if higher than 2L/IMAC)
downgradient. Also determine (i) predicted maximum concentration
of each COI in groundwater and the time that occurs and (ii)
predicted time to reduce all COI concentrations in groundwater to 2L
standards/IMACs or background if higher at the following locations:
a. Along most susceptible portion of the compliance boundary
b. At most susceptible supply well
c. At most susceptible future groundwater use area
d. At most susceptible SW(s)
5. For "groundwater remediation" predictive modeling that shows
source removal (excavation) and other source control measures AND
active groundwater remediation, provide a comprehensive list of all
potential receptors that are or are predicted to be impacted and a
map for each COI showing the maximum predicted radius of travel of
that COI above 02L/IMAC (or background, if higher than 02L/IMAC)
downgradient. Also determine (i) predicted maximum concentration
of each COI in groundwater and the time that occurs and (ii)
predicted time to reduce all COI concentrations in groundwater to
02L standards/IMACs or background if higher at the following
locations:
a. Along most susceptible portion of the compliance boundary
b. At most susceptible supply well
C. At most susceptible future groundwater use area
d. At most susceptible SW(s)
VA

iv. For remedial alternative 1, describe:
1. Protection of human health and the environment
2. Compliance with applicable federal, state, and local regulations
3. Long-term effectiveness and permanence
4. Reduction of toxicity, mobility, and volume
5. Short term effectiveness at minimizing impact on the environment
and local community
6. Technical and logistical feasibility
7. Time required to initiate
8. Predicted time required to meet remediation goals described in D. a.
L 3. above
9. Cost
10. Community acceptance
E. Proposed remedial alternative(s) selected for the source area 1 and/or sub -areas of source
area 1.
Note that multiple corrective actions may be necessary to address different locations within
source area 1 or any of its sub -areas. This could involve "compartmentalizing" the source area
and describing the specific selected corrective actions for each "compartment."
a. Description of proposed remedial alternative and rationale for selection
L Specific section of 02L .0106 being addressed by the proposed remedy [e.g.
02L .0106 (1) or (k)]
ii. Will a hybrid remedy consisting of more than one corrective action be used?
If so, describe.
iii. Will proposed remedy or hybrid remedy meet concentration cleanup goals
defined in D. a. i. 3. above?
iv. Treatability studies
1. Results of post-CSA Update treatability studies, if applicable
v. Additional site characterization needed to support the proposed remedy
1. Locations and specific testing, sampling, modeling, and (or) data
analysis
2. Schedule for data collection and reporting
b. Design details
I. Process flow diagrams for all major components of proposed remedy
ii. Engineering designs with assumptions, calculations, specifications, etc.
iii. Permits needed for proposed remedy and approximate schedule for
obtaining them
iv. Schedule and cost of implementation
v. Measures to ensure the health and safety of all persons on and off site
vi. Description of all other activities and notifications being conducted to ensure
compliance with 02L, CAMA, and other relevant laws and regulations
c. For 02L .0106 (1) CAP, provide requirements outlined in DWR's Monitored Natural
Attenuation for Inorganic Contaminants in Groundwater. Guidance for Developing
Corrective Action Plans Pursuant to NCAC 15A [02L].0106(I).
d. For 02L .0106 (k) CAP, provide requirements outlined in 02L .0106 rule
e. Sampling and reporting
i. Proposed progress (i.e. "effectiveness") reports and schedule
ii. Proposed sampling and reporting plan during active remediation
8

iii. Proposed sampling and reporting plan after termination of active
remediation (if proposed)
1. Decision metrics for termination of active remediation and start of
"monitoring only" phase
A. Proposed wells for COI trend analysis
B. Proposed statistical method for trend analysis
f. Proposed interim activities prior to implementation
g. Contingency plan in case of insufficient remediation performance
i. Description of contingency plan
ii. Decision metrics (triggering events) for implementing contingency plan
7. PROFESSIONAL CERTIFICATIONS
Sealed and notarized professional statements of "true, accurate, and complete".
8. REFERENCES
9. TABLES
10. MAPS AND FIGURES
11. APPENDICES - Flow and Transport Modeling
For Flow model report content, refer to report titled 'Updated groundwater Flow and Transport
Modeling Report for Asheville Steam Electric Plant, Arden, NC (Ronald Falta and others, March
17, 2017). Also include the following:
• List of all model assumptions
• List all model limitations that affect output (including, for example, unconfirmed
boundary positions, unmodeled heterogeneities, scale of cell volume versus scale of well
observations, limited input data, limited data for calibration and calibration assessment,
etc.)
• List of variables for which sensitivity analyses were quantitatively presented
• Describe how model is being used in closure/corrective action design and review
For transport model report content, refer to report titled 'Updated groundwater Flow and
Transport Modeling Report for Asheville Steam Electric Plant, Arden, NC (Ronald Falta and others,
March 17, 2017). Also include the following:
• List of all model assumptions
• List all model limitations (including, for example, limitations of Kd, unconfirmed boundary
positions, unmodeled heterogeneities, scale of cell volume versus scale of well
observations, limited input data, limited data for calibration and calibration assessment,
etc.) that affect output
• List of variables for which sensitivity analyses were quantitatively presented
• Describe how model is being used in closure/corrective action design and review
APPENDICES - Geochemical Modeling
0

For geochemical report content, refer to memorandum titled, 'Geochemical modeling of
constituent behavior at CAMA disposal sites' (Brian Powell, January 29, 2018) and memo titled
'Summary and Comments on Geochemical Modeling Outline with MNA Considerations (Bill
Deutsch, February 7, 2018). Also include the following:
• List of all model assumptions
• List all model limitations (including, for example, lack of pertinent data for points along
an individual flow path, if applicable, heterogeneities, limited input data, etc.) that affect
output
• List of variables for which sensitivity analyses were quantitatively presented
• How model is being used in closure/corrective action design
APPENDICES — Other
10

Water Resources
Environmental Quality
May 14, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: Approval of Revised Background Threshold Values
James E. Rogers Energy Complex (Formerly Cliffside Steam Station)
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
The North Carolina Department of Environmental Quality's (DEQ) Division of Water Resources
(DWR) has reviewed Duke Energy's calculated revised provisional background threshold values
(PBTVs) for soil and groundwater for the subject facility. DWR reviewed the calculated PBTVs based
on background data provided in the revised Comprehensive Site Assessment (January 2018), using the
Revised Statistical Methods for Developing Reference Background Concentrations for Groundwater
and Soil at Coal Ash Facilities dated May 26, 2017 and additional guidance provided in the December
7, 2017 email from Steve Lanter to Ed Sullivan and John Toepfer. DWR hereby approves all accepted
PBTVs for groundwater and soil as outlined in the attached tables. These accepted PBTVs shall
become the Background Threshold Values (BTVs) for the facility and will serve as a basis. for the
proposed remedial alternatives in the upcoming Corrective Action Plans.
Per 15A NCAC 02L .0202(b)(3), where naturally occurring substances exceed the established
groundwater standard, the standard shall be the naturally occurring concentration as determined by the
Director. Therefore, BTVs calculated above the groundwater standards or Interim Maximum
Allowable Concentrations (IMACs) in accordance with the provisions in 15A NCAC 02L .0202 and
accepted by DWR, shall become the enforceable groundwater standard. Otherwise, the enforceable
groundwater standards shall be those listed under 15A NCAC 02L .0202(h) including any effective
IMACs.
For soils, PBTVs that are calculated above the DEQ Division of Waste Management Inactive
Hazardous Sites Branch's (IHSB) Preliminary Soil Remediation Goals (PSRG) for the protection of
groundwater shall become the BTVs for use in developing an appropriate corrective action strategy.
For compounds that do not have an established PSRG, but do have a groundwater standard (i.e. chloride
and sulfate) pursuant to 15A NCAC 02L .0202, use the calculation provided in the PSRG table to
establish a PSRG if the required site -specific data are available. The PSRG table can found under the
IHSB website at: https:Hdpg.nc.gov/about/divisions/waste-management/superfund-section/inactive-
hazardous-sites-program.
--:,"Nothing "Nothing Compares _ 1%�
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional Operations Section
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

The attached tables outline DWR's concurrence/non-concurrence with Duke Energy's proposed
calculated PBTVs for groundwater and soil. For all of Duke Energy's calculated PBTVs that are listed
as acceptable, DWR hereby approves those values. For those BTVs not found acceptable, justification
is provided on the attachment and Duke Energy is responsible for providing revised values for review
and approval. For any BTVs found to be unacceptable due to an inadequate dataset, Duke Energy shall
continue to collect data until an adequate dataset is achieved and a valid statistical calculation can be
performed.
Along with the specific comments provided on the attachments, DWR offers the following general
comments with regards to the BTVs:
• Please note that the IHSB's PSRG table was revised in February 2018. With respect to the
constituents being evaluated for the CSA, the following PSRG values have been revised.
o PSRG for Aluminum is currently 110,000 mg/kg.
o PSRG for Chromium is currently 3.8 mg/kg.
o PSRG for Molybdenum is currently 7.1 mg/kg.
o PSRG for Vanadium is currently 350 mg/kg.
DWR recognizes that, as new information is gathered going forward, the approved BTVs may be
refined. Thus, there will be need for a periodic review and recalculation of the BTVs. The timeframes
for the periodic review will be established by DWR at a later date and any revised BTVs will be subject
to approval by DWR's Director.
If you have any questions, please contact Ted Campbell (Asheville Regional Office) at [phone]
or Steve Lanter (Central Office) at [phone].
Sincerely,
Lin a Culpepper, Director
Division of Water Resources
Attachments
cc: ARO WQROS Regional Office Supervisor
WQROS Central File Copy

James E. Rogers Energy Complex - Groundwater Background Threshold Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy Calculated PBTVs from
CSA Report (January 31, 2018)
-
15A NCAC 02L
Standard or
IMAC
DWR Concurrence (Acceptable/Not Acceptable)
Comments
Flow Unit
Flow Unit
Shallow
Deep
Bedrock
Shallow
Deep
Bedrock
H
S.U.
4.4-6.1
4.8-6.1
5.4-7.4
6.5-8.5
Accr stable
Acceptable
Acceptable
Alkalinity
mg/L
13.67
19.74
53
NE
Acceptable
Acceptable
Acceptable
Aluminum
yWL
253
290
208.2
NE
Acceptable
Not Acceptable
Acceptable
For Deep Flow Unit - ARO calcualted the value at 100.
Antimony
1
1
1
1
Acceptable
Acceptable
Acceptable
Arsenic
µg/L
1
1.303
1
10
Not Acceptable
Not Acceptable
Acceptable
For Shallow Flow Unit - ARO calculated the value at 0.5.
For D"V Flow Unit - ARO calcualted the value at 0.8.
Barium
t L
73.08
23
19.33
700
Acceptable
Acceptable
Acceptable
Beryllium
L
0.188
0.2
1
4
Acceptable
Acceptable
Acceptable
Bicarbonate
mg/L
14.42
18.13
68.82
NE
Acceptable
Acceptable
Acceptable
Boron
_WL
50
50
50
700
Acceptable
Acce +table
Acceptable
Cadmium
1
1
1
2
Acceptable
Acceptable
Acceptable
Calcium
ingli,
3.221
11
16
NE
Acceptable
Acceptable
Acceptable
Carbonate
mg/L
5
5
5
NE
Acceptable
Accc ble
Acceptable
Chloride
m!zR.
7.7
5.1
8.656
250
AcccIftble
Acceptable
Acceptable
Chromium (VI)
0.452
0.16
0.12
NA
Acceptable
Acceptable
Acceptable
Chromium
pgfL
3.968
1.791
3.567
10
Acceptable
Acceptable
Not Acceptable
For Bedrock Flow Unit - ARO calculated the value at 1.9.
Cobalt
pyZL
10.65
5.1
1.497
1
Acceptable
Acceptable
Acceptable
Copper
t /1,
6.569
9.453
5
1000
Acceptable
Acceptable
Acceptable
Iron
684
515
6220
300
Acce
Itable
Acceptable
Ace ble
Lead
tell.
1
1
1
15
Accc table
Acceptable
Acc ble
Magnesium
me'I
2.479
1.6
2.328
NE
Acceptable
Acceptable
Acceptable
Man . nese
t
168.8
78.31
89.4
50
Acceptable
Acceptable
Acceptable
Mercury
t A
0.2
0.2
0.2
1
Accc table
Acceptable
Acceptable
Methane
t j L
10
3.151
10
NE
Acceptable
Acceptable
Acceptable
Molybdenum
t
1
1
1.716
NE
Acceptable
Acceptable
Acceptable
Nickel
ppl,
6.256
12.56
5
100
Acceptable
Accr table
Acceptable
Nitrate + Nitrite
m -N/L
8.837
2.8
0.92
l l *
Acceptable
Acceptable
Acceptable
Potassium
me'L
5
5
5
NE
Acceptable
Acceptable
Acceptable
Selenium
r
1
1
1
20
Acceptable
Acceptable
Acceptable
Sodium
m 'l.
6.139
4.41
7.42
NE
Acceptable
Acceptable
Acceptable
Strontium
ljVjL
36.73
56.14
107.1
NE
Acceptable
Acceptable
Acceptable
Sulfate
m
1.169
10
15.1
250
Acceptable
Acceptable
Acceptable
Sulfide
m 1'L
0.1
0.1
0.1
NE
Ace,-Ttable
Accc table
Acceptable
TDS
m9fL
75.47
70.98
120
500
Acceptable
Acceptable
Acceptable
Thallium
0.117
0.063
0.2
0.2
Accc table
Acceptable
Not Acce stable
For Bedrock Flow Unit - ARO calculated the value at 0.1.
TOC
ma -I
1
1
1
NE
Acceptable
Acceptable
Acceptable
Vanadium
RE!
0.8
1.095
0.37
0.3
Acce table
Acceptable
Acceptable
Zinc
PEY,.
15
15.03
10
1000
Acceptable
Acceptable
Acceptable
Radium (Total)
i/L
2.58
1.51
3.1
NE
Acceptable
Acceptable
Acceptable
table
Uranium Tntall
t !/ML
0.0005
0.0005
0.0005
NE
Accc table
Acceptable
Acceptable
NA - Not Applicable S.U. - Standard Unit
ND - Not Detected TOC - Total Organic Carbon
NE - Not Established TDS - Total Dissolved Solids
mg/L - milligrams per liter µg/mL - micrograms per milliliter
pCi/L - picocuries per liter µg/L - micrograms per liter
Radium (Total) - Radium-226 and Radium-228 combined Uranium (Total) - Uranium-233, Uranium-234, Uranium-236, and Uranium-238 combined
*The l5A NCAC 02L Standard is 10 mg/L for Nitrate and 1 mg/L for Nitrite (added for a total of 11 mg/L)

James E. Rogers Energy Complex - Soil Background Threshold Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy
Calculated PBTVs
from CSA Report
(January 31, 2018)
PSRG Protection of
Groundwater (as of February
2018)
DWR Concurrence
(Acceptable/Not Acceptable)
Comments
pH
S.U.
4.0-6.8
NA
Acceptable
Aluminum
mg/kg
1 61758
110000
Acceptable
Antimony
mg/kg
0.64
0.9
Not Acceptable
ARO calcuated the value at 0.27.
Arsenic
mg/kg
7.759
5.8
Acceptable
Barium
mg/kg
198.2
580
Acceptable
Beryllium
mg/kg
1.769
63
Acceptable
Boron
mg/kg
31
45
Not Acceptable
ARO calcuated the value at 21.7.
Cadmium
mg/kg
0.032
3
Not Acceptable
ARO calcuated the value at 0.03.
Calcium
mg/kg
281.9
NE
Acceptable
Chloride
mg/kg
17.41
NE*
Acceptable
Chromium
mg/kg
142.4
3.8
Acceptable
Cobalt
mg/kg
47.53
0.9
Acceptable
Copper
mg/kg
39.76
700
Acceptable
Iron
mg/kg
74362
150
Acceptable
Lead
mg/kg
4437
270
Acceptable
Magnesium
mg/kg
8225
NE
Acceptable
Manganese
mg/kg
672
65
Acceptable
Mercury
mg/kg
0.098
1
Not Acceptable
ARO calcuated the value at 0.034.
Molybdenum
mg/kg
7.7
7.1
Not Acceptable
ARO calcuated the value at 1.2.
Nickel
mg/kg
71.91
130
Acceptable
Nitrate (as N)
mg/kg
0.26
NE
Acceptable
Potassium
mg/kg
13697
NE
Acceptable
Selenium
mg/kg
3.777
2.1
Acceptable
Sodium
mg/kg
198.1
NE
Acceptable
Strontium
mglkg
9.9
NE
Acceptable
Sulfate
mg/kg
13
NE*
Acceptable
Thallium
mg/kg
1.114
0.28
Acceptable
Vanadium
mg/kg
160.7
350
Acceptable
Zinc
mg/kg
1403
1200
Acceptable
-consnment nas LL samara or imAu. use cawwation m me rbtcu taDie to aetemune value.
NA - Not applicable
ND - Non -Detect
NE - Not Established
mglkg - milligrams per kilogram
S.U. - Standard Unit

[_ 5
Water Resources
Environmental Quality
June 29, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: 2018 Comprehensive Site Assessment Update Comments
James E. Rogers Energy Complex
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
On January 31, 2018, the North Carolina Department of Environmental Quality's (DEQ's)
Division of Water Resources (DWR) received the Comprehensive Site Assessment (CSA) Update
for the subject facility. Based on the review conducted to date, the DWR has concluded that
sufficient information has been provided in the report to allow preparation of the Corrective Action
Plan (CAP); however, there are data gaps that must be addressed prior to, or in conjunction with,
preparation of an approvable CAP.
As described in the attached itemized list of CSA Update comments (Attachment 1), additional
data and/or data analysis will be needed to address data gaps, complete evaluation of exposure
pathways, predict time and direction of contaminant transport, and ultimately refine remedial
design. The assessment of all primary and secondary source areas (including, but not limited to,
impoundments, cinder storage areas, coal piles, and contaminated soils) must be included in the
CAP, or in a CAP amendment. The DWR expects that information collected regarding the source
areas will be used to formulate the CAP recommendations. For source areas where this may not
be possible or areas where pollutants may be hydraulically isolated, please contact me to discuss.
In an email dated April 18, 2018, Duke Energy proposed a CAP submittal date of October 31,
2018. However, as you are aware, Duke Energy and the DEQ are currently discussing revisions
to the CAP deadlines and the final revised date for CAP submittal will be communicated to Duke
Energy in a separate correspondence.
---' Nothing Compares--A.--
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional Operations Section
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

An overview of CSA Update data gaps includes the following:
• Delineation of groundwater exceedances is, for certain areas and constituents, incomplete
or in need of revision.
• Report contents are presented in a data summary format with a lack of conclusive data
analysis and interpretation of site conditions.
• An understanding of the major factors that control contaminant distribution and transport
within each source area is incomplete.
• Concentration -distance and concentration -time plots needed to help understand
contaminant transport and plume characteristics are, in several cases, not constructed
properly or interpreted correctly.
• Potentiometric mapping and understanding of groundwater flow directions are, in certain
areas, unreliable or appear to be incorrect.
• The report does not acknowledge that closure planning, corrective action planning, and risk
evaluation are needed for each source area individually rather than for the facility as a
whole; as a result, individual source areas are not described or assessed with adequate
specificity.
• The report states that CCR poses no risk to private supply wells near the facility; the
rationale and evidence used to substantiate this position is incomplete.
The data gaps related to the site assessment at the facility, including those related to primary and
secondary sources other than impoundments, may limit the cleanup remedy and site management
strategies for a source area. The lack of a well -documented interpretation of the existing data, or
missing data that the DEQ believes will be necessary to support proposed corrective action, may
limit DEQ's ability to approve certain corrective action measures [e.g. 15A NCAC 02L .0106(1)].
For example, monitored natural attenuation cannot be approved for source areas where surface
water samples have not been collected (but could be collected) and that demonstrate the
groundwater discharge does not result in exceedances of 15A NCAC 2B .0200 regulatory
standards.
Please refer to the letter to Duke Energy dated May 14, 2018, for approved background threshold
values developed for the facility as part of the CSA Update.
Duke Energy should contact the Asheville Regional Office to initiate the scheduling of a meeting
between DWR and Duke Energy's technical staff (including contractors) to discuss data gaps in
greater detail. Promoting regular dialogue in a small group format assists in addressing questions
and problems that may come up during the development of the CAP, and better ensures that Duke
Energy is meeting DWR's expectations.

If you have any questions, please feel free to contact me at [phone].
Campbell (Asheville Regional Office) at [phone] to discuss any
regarding the CSA Update data gaps in more detail.
Sincerely,
/onRisg?rd,Section Chief
Division of Water Resources
Attachment: James E. Rogers CSA Update Comments
cc: ARO WQROS Regional Office Supervisor
WQROS Central File Copy
Please contact Ted
additional questions

James E. Rogers Energy Complex
Condensed Comments for Comprehensive Site Assessment Update Report
Submitted January 31, 2018
Delineation of Groundwater Contamination
• Delineation of groundwater contamination (horizontal and vertical extent and regulatory
exceedances) is incomplete or in need of revision. Isoconcentration maps must depict all
available data to include Appendix III and Appendix IV constituents from all sampled
wells, including CCR wells and wells shown as "NM" (not measured) turbidity'. Boron in
wells with elevated pH/turbidity must be used in isoconcentration maps. Provisional
Background Threshold Values (PBTVs) above 15A NCAC 02L .0202 groundwater quality
standards (2L) or Interim Maximum Allowable Concentrations (IMAC) should be
contoured and identified as the regulatory exceedance standard. PBTVs that have been
revised since the report was submitted in January need to be updated with the final BTV
values for all mapping and interpretation. 2L/IMAC/PBTV contours should be shown as
"open" when data do not exist downgradient of the contour; several contours are incorrectly
shown as "closed" and inappropriately imply that exceedances do not occur past the
contour line (e.g. fig. 11-16 for shallow cobalt; fig. 11-37 for shallow vanadium; fig. 11-8
for deep boron; etc.). The position of the compliance boundary for the active basin and ash
storage area has been revised since the report was submitted; the revised boundary should
be used for all mapping and interpretations in all future submittals.
• Additional wells are needed to ensure adequate horizontal and (or) vertical delineation in
the following areas:
o Ash storage area: need a BR well at AS-8, and need sampling at CLP-I. Newly
identified Unit 6 source area: need a S/DBR well nest 200 ft north of GWA-425,
a S/D/BR well nest 150 ft west of SW-SC-6, and any other wells as needed.
o Active basin — west (dam): need a S/D/BR well nest 200 ft N or north-northeast
of CCR-9D. Also need well(s) beyond AB-3 to determine whether groundwater
flow direction is west toward Suck Creek or northwest toward the ash storage area,
and wells or analysis to assess underflow of Suck Creek in this area.
o Active basin — south: need well(s) to determine whether groundwater flow
direction is northwest toward the dam at Suck Creek or to the southwest directly to
Suck Creek in the area of GWA-27DA, CCR-14D, and CCR-13D; need well(s) (or
analysis) to determine where boron in CCR- 16S (2050 ug/L) migrated since boron
in CCR-16D i§ BDL and, 200 ft downgradient, boron in GWA-47D is 300 ug/L
and rising.
o Other: Wells are needed in various locations across the facility as proposed via
email from Ryan Czop to Ted Campbell on 4/12/18, as follows: GWA-21BRL,
MW-11BRL, CCR-9BRL, CCR-12BRL, GWA-11BRL, and CCR-U5-4BRL; the
Some wells were omitted (e.g. CCR-9D; etc.), and others were not properly contoured (e.g. GWA-30BR, Fe = 8730
ug/L; etc.). Numerous wells with data were shown as "NM" (not measured). And some CCR wells did not depict
Appendix IV constituents (e.g. CCR-313R, CCR-41), and CCR-51)).
Page 1 of 6

need for CCR-3BRL and CCR-U5-3BRL is unclear and may be discussed further
with the Asheville Regional Office at the discretion of Duke.
• Ash and pore water delineation within the waste boundary is incomplete. Given the large
size of the source areas and the long and complex history of ash placement and coal
chemistry makeup, relatively few pore water locations were sampled, and few contaminant
cross section maps were presented. The geologic cross sections mapped across the waste
boundaries do not sufficiently describe the position, volume, and thickness of ash, saturated
ash, and saturated ash post -de -watering. At a minimum, as -built drawings and historic
aerial/topographic maps need to be assessed and presented in conjunction with ash boring
data to augment the sparse number of available data.
In addition, need discussion, by source area, of spatial variability of ash and pore water
within the waste boundary, whether the existing data are adequate to assess this variability,
and if not, what additional data are proposed. Need discussion about the adequacy (or lack)
of data used to map (interpolate/extrapolate) the ash and saturated ash in cross section.
Need additional contaminant cross sections and associated discussion of plume evolution
from source to receptor. If the ash will be capped -in -place as the method of source control,
need discussion about the implications of the volume and location of saturated ash on
contaminant concentrations and migration. Cap -in -place inhibits infiltration but does not
address lateral groundwater/contaminant flow; the Corrective Action Plan (CAP) must
explain how the lateral component of groundwater flow and resulting contaminant flux will
be addressed if source material remains in place.
GW Flow, Contaminant Flow, and Transport
Boron values within all wells (high pH/turbidity or otherwise) and independent of
concentration need to be presented and used to map horizontal and vertical extent, map 2L
exceedances, and interpret plume movement and (or) expansion. Ninety-one (91) wells at
Cliffside contain boron concentrations between background and 700 ug/L, but these boron
values were not used to understand contaminant migration downgradient of the source
areas.
An understanding of the major factors that control contaminant occurrence and transport is
incomplete. In describing the purpose (p. 1-1) and technical objectives (p. 1-6) of the
Comprehensive Site Assessment (CSA), the report does not acknowledge this central need.
Instead, the report mainly presents data results and summarizes them in the fashion of a
data summary report. Both General Statute 130A-309.209 and 02L .0106 (g) state that the
site assessment must understand the major factors that control contamination and its
movement. Although the report presents maps (isoconcentration and potentiometric maps)
and plots (concentration -distance and concentration -time), these do not provide an
understanding of factors controlling contaminant occurrence and transport. Specific well
IDs, boring logs, and potentiometric and contaminant data should be used to assess
potential plume expansion, potential plume movement, and contaminant migration through
the three flow units (shallow, deep, bedrock) as pore water moves through the groundwater
system and discharges at receptors.
Page 2 of 6

Concentration -distance plots needed to help understand contaminant transport and plume
characteristics are, in several cases, not constructed properly or interpreted correctly. The
plots should utilize wells along a plume centerline/singular flow path, originate within a
source, and cover the same time period2. Need plots that utilize appropriately selected
wells and need accurate plot interpretations. Also, in its discussion of concentration -
distance plots the report makes no distinction between tracer -type contaminants (e.g. B and
SO4) and contaminants controlled largely by the local geochemistry (e.g. Fe, Mn, Tl, V,
etc.) and thus blurs the understanding of factors controlling concentrations with distance.
The discussion should at a minimum note that a) wastewater concentrations vary within
the waste boundary, b) certain contaminants are attenuated largely by dilution and
dispersion (B, e.g.) while other contaminants are attenuated by sorption and changes in
local geochemical conditions (Fe, Mn, Tl, e.g.), and c) results of geochemical modeling
will be provided in the CAP. The discussion could then attempt to explain how dilution
and dispersion have affected the distribution of the tracer -type contaminants using
concentration -vs -distance and concentration -vs -time plots from specific areas of concern.
Concentration -time plots needed to help understand potential plume movement and (or)
expansion were, in some cases, constructed using wells. of questionable relevance.
Concentration -time was plotted for a small handful of wells but it was not stated why those
wells were selected or why the results were meaningful. For example, the report shows
boron -vs -time plots (figs. 11-49 to 11 -5 1) that omitted a key and informative well location,
MW-20D. Boron has been increasing in MW-20D (from 100 to 600 ug/L) over six years,
calling into question whether concentrations of this and other contaminants will continue
to increase with time in this area of groundwater discharge. The well that was plotted
instead (GWA-21D), located 200 ft to the east, shows boron with essentially no change
over a three-year period (from 150 to 137 ug/L). It would be useful to understand why
concentrations are steadily increasing in MW-20D and are much lower and unchanging in
GWA-21D located 200 ft away. The discussion needs to provide a narrative about plume
movement or expansion and provide specificity (well IDs, boring logs, and contaminant
data). In addition, plots need to be constructed with a Y axis (concentration) that allows
discernment of meaningful concentration changes with time (use of arithmetic scale is
recommended over log scale).
2 In many instances this was not the case. For example, the plots for the deep unit at Units 1-4 basin (figs. 11-55 to
11-57) used two source area wells (IB-41) and IB-3D) and one side -gradient well (GWA-29D, which appears,
according to WL maps in the report, to receive GW flow from a clean recharge area). Similar issues were noted for
the plots associated with other source areas (e.g. MW-2DA is not on the same flow path as AS-6BRA according to
the potentiometric map of fig. 6-20). And using flawed logic, page 11-9 states that boron (and others) show an
increasing trend, from source to downgradient in the bedrock flow unit, but the supposed "source" well (AS-6BRA)
is not actually positioned within the source therefore the concentration -distance plot makes little sense. Other
problems were noted. For example, some plots included wells sampled two years apart (page 11-5) so it is not possible
to know whether the concentration changes are due to distance or time.
Page 3 of 6

• Potentiometric mapping and understanding of groundwater flow directions are, in certain
areas, unreliable or appear to be incorrect. Map revisions or improvements should address
the following issues:
o water level data are limited by a lack of wells or a lack of measurement in existing
wells) (e.g. the area near GWA-31, north-northwest of AB-4, north-northeast of
GWA-39 in figs. 6-15 to 6-20);
o interpretation is incomplete or inaccurate (e.g. potentiometric contours in figs. 6-
15 to 6-21 near the active basin dam at Suck Creek suggest partial underflow rather
than discharge to the creek from both sides as described in the conceptual model;
o there is a general lack of specificity and discussion at a local scale (e.g. the location
of a groundwater divide in the south west portion of the active basin (north-
northwest of AB-4) was not discussed or mapped even though it is the area where
contaminated groundwater breaks and flows in one of three directions);
o important data were not collected (e.g. water levels in Suck Creek were not
measured so the potentiometric maps were created without this information);
o critical information was not depicted on the potentiometric maps themselves (e.g.
topographic contours need to be superimposed on potentiometric maps to help in
evaluating the reliability of the mapped potentiometric contours).
• In various instances the report purports to understand the cause of contamination when it
does not. For an example, see page 14-7, where it is states, without substantiation, that
cobalt contamination in bedrock groundwater "is due to natural geochemical conditions".
While this may or may not be true, the report implies knowledge that it does not have or
does not provide. This practice is not acceptable.
• The report states, for each source area, that "The well screens in the CAMA wells
accurately monitor groundwater conditions" (e.g. see page 11-7). However, no evidence,
analysis, or basis is provided for this broad statement. It is widely understood that
concentrations can increase or decrease sharply over short vertical distances, particularly
in a heterogeneous subsurface like at Cliffside. The values measured (particularly in deep
and bedrock wells) are a function of the location of the well (relative to the source) and the
specific vertical interval over which the well is screened. A well installed to properly
understand groundwater contamination and its movement is screened across the heart of
the contaminated plume, and the screen depth and length are chosen to account for
heterogeneities (preferential flow paths) in the subsurface that could concentrate
constituents in one vertical horizon over that of another. Only a careful, intentional
analysis of the data (e.g. contaminant concentrations versus local flow unit thicknesses
versus screen length and depth versus proximity to source) will answer the question "are
wells constructed to accurately measure maximum concentrations in a given flow unit in a
particular area?"
• Need all future reports associated with coal combustion residual (CCR) assessment,
closure, and (or) corrective action to be separated and organized by source area, and all
data, maps, tables, analysis, and interpretations pertinent to that source area to be discussed
together and with specificity as one narrative. As written, information from multiple source
Page 4 of 6

areas is intermixed in sections, paragraphs, and sentences across the report (e.g. pages 2-1,
2-11, 3-8, 3-9, 6-8, 6-9, 6-14, 7-7, 8-1, 9-2, 9-6, 10-20, 12-1, 12-4, 14-3, 14-19), and the
reviewer is left to tease out and reassemble the information to gain an understanding of
conditions for a particular source area.
Other Primary and Secondary Sources
• For each source area need map of soil above Protection of Groundwater (POG). Need
discussion of how and why soil contamination occurs outside waste boundary.
• Need discussion describing whether additional sediment assessment is needed near
locations with sediment contaminant concentrations above the POG. Need discussion
describing proposed sediment sample locations in specific groundwater discharge areas
along the Broad River.
• Need assessment of raw coal piles.
• Need assessment of newly identified source area near unit 6.
Maps, Figures, and Tables
• Some figures, tables, or text are incomplete, in error, not current, or not used/referenced in
the report. Specific examples to be provided under separate cover. Maps, figures, and
tables need to use reporting limits instead of ND (non -detect).
Modeling
Geochemical controls on groundwater contaminants were not defined in the report. It was
agreed that this information and all associated documentation and modeling will be
presented, for each individual source area, as part of or prior to the CAP submittal.
Modeling direction provided by the Division and provided in the CAP content letter from
S. Jay Zimmerman to Paul Draovitch, April 27, 2018 needs to be incorporated into the
modeling report. All additional direction provided by Bill Deutsch (geochemical
consultant) needs to also be incorporated into the modeling report.
The CSA did not provide predicted contaminant concentrations at specific locations. It
was agreed that this information and all associated documentation and modeling will be
presented, for each individual source area, as part of or prior to the CAP submittal.
Modeling direction provided by the Division and provided in the CAP content letter from
S. Jay Zimmerman to Paul Draovitch, April 27, 2018 needs to be incorporated into the
modeling report.
'�17
• While the Division is receptive to the argument that CCR impacts to area supply wells are
unlikely, the rationale and evidence used to substantiate this is inadequate. The report
Page 5 of 6

states generically that several factors may affect the concentrations observed in supply
wells, including well construction, geochemistry, and flow direction, but few details were
not provided. For any supply well with a constituent above 2L/IMAC/BTV, need
discussion that considers multiple lines of evidence that substantiates the Duke position.
These should include:
o whether alternative water has been supplied to the well owner;
o whether the well has been abandoned;
o boron levels in the supply well;
o constituent concentrations above 2L/IMAC/BTVs;
o the water type in the supply well and how it relates to background bedrock
conditions (show Piper diagram of all supply wells and all bedrock wells upgradient
of source, within source, and downgradient of source;
o topography, assumed hydrologic divides such as the Broad River, and groundwater
flow directions in the area between the source area and the supply well(s) in
question;
o actual geochemical conditions (well IDs and data) within the supply well that are
believed to be influencing the observed exceedance;
o mapped particle tracks from numerical modeling; and
o any other relevant factor(s).
The amount of documentation expected for a given supply well or group of supply wells is
dependent upon the constituents and concentrations in the well and its proximity to the ash
basins.
Page 6 of 6

To: Duke Energy (Ryan Czop)
From: Asheville Regional Office (Landon Davidson)
Copy to: Jon Risgaard, Ed Sullivan, John Toepfer, Steve Lanter
Date: July 17, 2018 (via email)
Subject: Specific comments (28 pages in total) Pertinent to Individual Source Areas and
to the report titled 'Cliffside CSA Update' (Synterra, January 31, 2018)
COMMENTS PERTINENT TO EACH SOURCE AREA
ASH STOAGE AREA
1. The ash storage area is made up of two smaller areas known as the western storage area (-6 acres)
and the eastern storage area (-5 acres). The western area is the area of concern as it contains CCR
material and is associated with contaminated GW flowing northward and discharging to the Broad River
receptor. The eastern area appears to contain only benign native fill material based on the available
record and GW quality results and appears to be of no further concern. This point is only inferred in the
CSA and needs to be stated directly for purposes of CAP design.
2. The determinations of 2L/IMAC GW contamination in need of restoration, as presented in the CSA,
are based on an incorrect compliance boundary drawn too far to the north. The compliance boundary
in fig. 2-10 is incorrect. The map provided as fig. 1, dated 3/7/18, (see attachment) shows the correct
compliance boundary. Only wells AS-1SB/D, CCR-7S/D, and CLMW-1 in the central and (or) southern
portion of the storage area (fig. 2-10) are within the compliance boundary and therefore exempt from
02L exceedances. All other wells are outside the compliance boundary and, if contaminated, represent
GW that must be restored to 2L/IMAC standards. AS-7S is an exception since it is a pore water well.
3. Contaminated GW in need of restoration exists in the shallow, deep, and BR flow units on or beyond
the compliance boundary'. It is unknown whether BR contamination needs restoration east of AS-2BR
' Shallow GW exceedances outside the CB and in need of restoration at the western ash storage area include B,
SO4, TDS, Co, Mn, Se, TI, Sr. The farthest downgradient shallow well just west of the toe (AS-2S) contains
exceedances of B, SO4, TDS, Co, Mn, Se, TI, Sr, and the farthest downgradient shallow well in the central portion
(AS-8S) contains GW exceedances of Fe, Mn, Sr.
Deep GW exceedances outside the CB and in need of restoration include B, Cr, Fe, Mn, Sr. The farthest
downgradient deep well just west of the toe in AS-21), contains GW exceedances of Mn, Sr, and the farthest
downgradient deep well in the central portion (AS-8D) contains GW exceedances of B, Fe, Mn, Sr.
BR GW exceedances outside the CB and in need of restoration include: Mn, Sr, Co, V. The farthest downgradient
shallow well just west of the toe (AS-2BR) contains BR GW exceedances of Mn and Sr. The farthest downgradient
BR well in the central portion contains GW of unknown CCR contamination due to high pH in AS-7BRU and AS-7BR
and no BR well at AS-8.

because the only BR wells available in the central portion of the site contain high pH (AS-7BRU/BR)
which resulted in contaminant data that was "invalid". An additional BR well is needed near AS-8 or
CLP-1 to define the lateral extent of restoration that will be needed.
4. GW contamination in the eastern half of the western storage area was not defined. The report
recommends only one additional well location for the western ash storage area, well AS-7 (45 to 55 ft
bls) but does not explain why. The report does not explain why CLP-1 was not measured for WLs or
sampled for GW quality. Well CLP-1 needs to be sampled to determine the lateral extent of
contamination in need of restoration in the NE portion of the western storage area.
5. The conceptual model of GW flow directions from the western storage area is inconsistent across
various sections of the CSA. For example, page 15-10 states that the "western part of the ash storage
area discharges to Suck Creek", but other report sections and the potentiometric maps in figs. 6-16 to 6-
20 suggest instead that GW moves northward and discharges directly to the Broad River. The CSA needs
to be accurate and consistent on this point.
6. The CSA did not fully define the waste and waste footprint for the western storage area. Ash was
encountered at only two borings within the waste boundary, only one of which was saturated. Soil was
sampled beneath ash in only two locations (one depth each). The CSA stated uncertainly that "this
[western] storage area was probably created when ash was removed from the active ash basin in the
1980s....", and that "the eastern portion of the ash storage area may be a spoils area remnant of soil
from embankment dam construction". However, Duke has provided great detail on this area in letter
correspondence to the Division (7/22/16; 12/6/16), in internal memos (12/9/15), and in engineering
drawings (3/1/73; 10/3/16). In addition, the report states that "the combined ash storage area
footprint... reportedly contains approximately 170,000 cubic yards of ash material". The report provides
no reference or basis for this estimate which appears to have been computed from the interpolated
cross sections I -I' (fig. 6-10) and J-J' (6-11). The description provided in the CSA is inadequate. The CSA
needs to reference and discuss historic engineering drawings, aerial photographs, and topographic maps
to help define the footprint of the impacted area. The report needs to reference the data used to
estimate the waste volume.
7. The description of contaminated GW was focused mostly on simply summarizing the mapped and
tabled data. Very little interpretation was provided to explain the source of or reason for the observed
concentrations in different areas within and surrounding the ash storage area, whether of ash, pore
water, or upgradient or overlying contaminated units. A map was provided showing the upward or
downward trend of boron in most wells across the facility but this map was not actually used in any
meaningful way in discussions about local contaminant distribution and movement. No contaminant
cross sections were mapped through the source area. Pore water was not used to explain the
downgradient concentrations and movement of contamination.
8. Well data needed to understand and map the GW contamination in need of restoration were limited
or not available at the time of report submittal (e.g. AS-8S/D and GWA-54S/D/BRO). And only one pore
water well was installed (AS-7S). Pore water contributing contamination to the underlying GW system
generally was not discussed.
2

9. The report suggested in passing that a portion of the contaminated GW from the active basin to the
SE migrates through the ash storage area before it discharges to the Broad River receptor, but few
details were provided. For example, the report did not provide a discussion of the GW divide where,
depending on the location, GW will move either toward the Suck Creek dam, the western ash storage
area, or the northern dam at the Broad River. WL maps show very widely spaced contours in this area
so the inferred GW flow directions are generalized and not specific here. To support CAP design, the
CSA needs to map GW flow directions near the GW divide and describe in detail contaminant
concentrations entering the site from the SE.
10. The location of SW sample CLFSP059 located north of the ash storage area was not mapped (fig. 2-
10). This location contained Al (860) above the EPA criteria of 87 and needs to be presented
accordingly. Remediation alternatives are limited in 02L .0106 if contaminated GW causes exceedances
of SW standards, and the CSA needs to evaluate this possibility carefully.
11. The CSA states that only Mn, Sr, and V are being considered for MNA in the CAP for the western
storage area. The CSA needs to state how these and only these constituents were selected for
consideration.
12. An assessment is needed of the potential impact on the leaching of saturated ash due to river stage
fluctuations and (or) GW level fluctuations.
RAW COAL PILES
1. Coal pile impacts to groundwater were not assessed in the report. The coal piles may represent
another source area whose GW must be restored. GW flow from the area of the coal piles is to the
Broad River. However, wells do not exist to determine where along the river contaminated GW
discharge would occur. Based on topography and the pile locations, about 600 to 800 feet of river
frontage potentially could receive discharge. In addition, the CSA did not discuss or map the
infrastructure (e.g. lined and bermed areas) designed to limit the movement of coal pile leachate.
2. Some GW from the easternmost coal piles likely flows beneath units 1-4 inactive basin and would
add to the GW contamination in that area. While it is recognized that the coal piles are being assessed
on a different schedule, any GW contamination influences to units 1-4 basin needs to be documented
and accounted for as part of any proposed corrective action for either source area. Any CAP
development needs to understand where contaminated GW is moving and discharging in this area. It is
recommended that at least one well nest be located about 250 ft NW of GWA-14, between the coal pile
and the units 1-4 basin waste boundary. Other shallow wells/piezometers need to be strategically
located to determine quality and areas of discharge to the river. These wells should be quickly installed,
sampled, and used in support of CAP development.
UNIT 5 INACTIVE BASIN
1. The source footprint (i.e. ash and saturated ash) was not well defined in the CSA. Although this
source area covers about 60 acres, ash and pore water were observed in only two locations soil was
sampled beneath ash in only one location. As -built drawings and historic topographic maps were not
3

referenced or discussed. Ash location and thickness were described in generic terms and without
corroborating well boring identifiers. Four geologic cross sections were provided but only two
intercepted ash, and extrapolations across very large distances were used to infer ash configuration. For
example, in geologic cross section D-D', two locations with ash were used to depict the configuration
(presence, depth, thickness, and saturated thickness) of ash across a 1400-ft span across the waste
boundary. In cross section E-E', zero locations with ash were used for to depict the ash configuration
across a 1000 ft span of the waste boundary. In cross section L-L', ash in one location was used to depict
the ash configuration across a 1200 ft span of waste boundary. And in cross section M-M', ash in one
location was used to depict the ash configuration across a 700 ft span of waste boundary. All existing
discharge piping and outfalls need to be clearly identified on maps and in text (leader arrows in fig. 2-10
are unclear, and the map text is not consistent with the report text).
2. The description of contaminated GW was focused mostly on simply summarizing the mapped and
tabled data. Very little interpretation was provided to explain the source of or reason for the observed
concentrations in different areas within and surrounding the unit 5 basin, whether of ash, pore water, or
upgradient or overlying contaminated units. A map was provided showing the upward or downward
trend of boron in most wells across the facility but this map was not actually used in any meaningful way
in discussions about local contaminant distribution and movement. Only one contaminant cross section
L-L' was mapped through the 58-acre source area. Pore water was not used to explain the
downgradient concentrations and movement of contamination. The potentiometric surface (fig. 6-16)
west and east of the site is mostly inferred due to the lack of WL data in these areas.
3. Concentration -versus -distance plots used wells that, in some cases, were inappropriate and resulted
in misinterpreted findings. According to potentiometric maps in figs. 6-16 (S), 6-18 (D), and 6-20 (BR),
the wells chosen for the plots in figs. 11-58 to 11-60 represent contamination emanating from different
areas within the waste footprint, a footprint with wastewater concentrations that vary sharply in space.
As a result, the plots did not represent plume evolution and attenuation downgradient as implied on
page 11-72. It should be noted that the wells used for geochemical flowpath modeling were different
than those used in the concentration -distance plots and were more appropriate for concentration -
distance evaluations.
4. The CSA states (p. 11-30) that four wells proposed for use in geochemical modeling (GWA-2BR, U5-
2S-SLA, U5-5BR, and U5-4BRA) have "zero valid sampling events" but no further mention is made about
the implications of this or about correcting this issue. The CSA needs to evaluate issues like this and
explain their significance.
z To properly analyze concentration -distance, plotted concentrations need to be from wells positioned along the
same flow path. This is particularly important in fractured rock settings like Cliffside. An alternate method could
be used if there were sufficient data (well) density, which would entail using an "aggregated concentration"
(geometric mean, for example) from wells within a certain distance range from the source. Then another set of
wells from a distance range further downgradient would also be aggregated. This would be repeated for different
distance ranges downgradient from the source. The aggregated concentration at each distance range would then
be plotted versus distance from the source to evaluate concentration versus distance. The method used in the CSA
- one contaminated source area well is compared with an unrelated far side gradient "clean" well - is generally says
little about not a useful analysis.
4

5. The CSA was unclear on the presence of discharge piping located in the area as the outlet from the
basin is described on page 3-4 as "a 60-inch RCP" that extends 500 ft through main dam, but the map in
fig. 2-10 states that there are "discharge pipes" (plural).
6. Page 6-18 states that "Packer tests .... were conducted in a minimum of five boreholes." No mention
was made regarding the actual number or the well locations used or, more importantly, what was
learned by the packer tests or why the results matter. The CSA stated only that to learn more about the
packer data, the reader should refer to Tables 6-17, 6-18, and Appendix C (1597 pages long). However,
table 6-17 pertains to porosity not packer test results. And table 6-18 states in a footnote that the
reader should refer to "Appendix H" for the raw packer worksheets, but Appendix H is part of Appendix
C of this report, and the raw permeability worksheets were intermixed with particle size distribution
figures, etc. It was confusing and time consuming to tease out this basic information.
7. Determinations of soil exceedances of POGs were not based on the latest BTVs. And it appears that
the soil exceedances identified in the report may be in error; the report stated that POGs were exceeded
for As, Cr, Co, Fe, Mn, Se, TI, and V, however, it appears instead that POGs were exceeded for As, Co,
Mn, Se, TI, Sb, Ba, Sr, and SO4. A portion of the exceedances were due to lab detection limits being
above the POGs.
8. Sediment exceedances were noted but the CSA did not discuss why these were important and how
they affect CAP design. In addition, not all sediment sample locations were shown on relevant figures 2-
10 and fig. 14-81 (e.g. CLFTD-004 and CLFTD-005 are not shown on either figure).
9. To focus the information needed for CAP design for the unit 5 basin source area, the CSA needs to
present SW results as "SWs associated with the unit 5 basin". Instead, the report intermixed all SW
samples collected up and down Suck Creek and Broad River in one sitewide discussion. And the CSA
needs to show all SW sample locations in the relevant figure (fig. 2-10) rather than a subset (e.g. March
2014 NCDENR locations were not shown). Finally, all SW sample results need to be compared to 213
standards, including EPA criteria (Al, Sb, TI, Co, Se, Ra, HS, and Sr).
10. A "white substance" was identified at the toe of the main dam on March 1 and 4, 2014 for which
DEMLR issued an NOD. The CSA stated dates on which the substance was not observed but should
instead report any dates on which it has been observed since the initial discovery. The geochemical
conceptual model and PHREEQC modeling needs to discuss this substance since its origin was reportedly
due to changes in geochemical conditions as waste water discharges into the wetland area.
11. Ecological risk was not evaluated for the area of the unit 5 basin (risk exposure area 4). The report
stated that "SW samples have not been collected in Exposure Areas 3 and 4 since the 2016 risk
assessment" and "AOW samples were not evaluated as part of the risk assessment due to being
included under the NPDES program". To allow a review in accordance with 02L .0106 (i), an ecological
risk assessment needs to be performed for area 4 (unit 5 basin).
12. The report states that "there are no indications that potential risks to off -site residences exposed to
groundwater exist" and that "these [private supply] wells reflect natural background concentrations.
While the Division is receptive to the argument that CCR impacts to area supply wells are unlikely, the
rationale and evidence (i.e. corroborating data) used in the report to make this case is mostly cursory
and spread in pieces across numerous sections of the report. The report states that "Recent (2016-
5

2017) analytical results from off -site water supply wells indicate that constituent concentrations are less
than 2L or less than PBTVs for site groundwater, with the exception of four vanadium detections".
However, the Appendix B table shows many more exceedances. Many of the exceedances are for wells
sampled in 2014 or 2015 which also needs to be considered. A total of 26 supply wells exceeded or had
a lab detection limit above the vanadium IMAC/BTV. One well exceeded the BTV for strontium. And
four wells exceeded the 2L/BTV for manganese.
13. The CSA states that only As, B, Cr, Co, Fe, Mn, Sr, SO4, TI, TDS, and V are being considered for MNA
in the CAP for the unit 5 basin source area. The CSA needs to state how these and only these
constituents were selected for consideration.
14. An assessment is needed of the potential impact on the leaching of saturated ash due to river stage
fluctuations and (or) GW level fluctuations.
UNITS 1-4 INACTIVE BASIN
Units 1-4 inactive basin is a former dammed ash basin about 15 acres in size located on the banks of the
Broad River, a Class IV-WS water of the state. The basin has been excavated and has no compliance
boundary.
1. The description of contaminated GW was focused mostly on simply summarizing the mapped and
tabled data. Very little interpretation was provided to explain the source of or reason for the observed
concentrations in different areas within and surrounding the units 1-4 inactive basin, whether of ash,
pore water, or upgradient or overlying contaminated units. A map was provided showing the upward or
downward trend of boron in most wells across the facility but this map was not actually used in any
meaningful way in discussions about local contaminant distribution and movement. Only one
contaminant cross section map was provided for the 15-acre area (H-H', figs. 11-76 to 11-90). Pore
water was not used to explain the downgradient concentrations and movement of contamination.
2. Section 10 summarized contaminant exceedances in GW that included areas well upgradient of the
basin (e.g. TDS in bedrock well GWA-44BR; SO4 in GWA-44S; Mn in GWA-33D; etc). However, the CSA
did not evaluate whether the upgradient wells that contained exceedances were hydraulically linked to
the downgradient wells with exceedances of the same constituent, nor did it compare the geochemical
conditions between the two. The CSA did not discuss the implications of the upgradient exceedances on
the need for GW restoration at the basin or for CAP design. It was suggested elsewhere in the report
that these areas may be associated with a newly identified source area in the vicinity of unit 6 (fig. 2-10)
but no further discussion of this new source was provided.
3. On page 11-6, the CSA incorrectly stated that "The vertical extent of the plume does not extend into
the transition zone or bedrock beneath or surrounding the Units 1-4 inactive ash basin at concentrations
greater than the 2L standard". Numerous exceedances of deep contamination were noted including, for
example, at GWA-10D, GWA-11BRU, I13-11D, and IB-3D.
4. The plots and discussion of contaminant concentration versus distance from source are misleading.
Referring to figs. 11-55 to 11-57, the CSA states that "Boron, chromium, cobalt, manganese, sulfate, and
0

thallium in the shallow flow layer show net increasing trends from the [units 1-4 basin] source area to
the waste boundary." The shallow unit wells to which this statement refers are actually pore water
wells and reflect variable conditions within the wastewater itself and do not reflect conditions in the
shallow GW flow unit. IB-4S-SL (B = 390) is in the middle of the basin and IB-3S (B = 590) is near the
edge of the basin. Both are in ash and both are representative of "source" conditions. Such wells do not
portray the attenuation of shallow boron away from the source area as intended, rather they portray
spatial variations in waste water concentrations. The fact that one source location has a higher pore
water concentration than another source location is not surprising and points to factors that affect
wastewater concentrations such as ash makeup, thickness, and local geochemistry. Concentrations are
not necessarily "trending" upward in the direction toward IB-3S as described, rather they reflect the fact
that spatial variations exist in wastewater within the waste boundary and may or may not be
gradational.
5. In some cases, the concentration versus distance plots were not constructed appropriately. For
example, two of the three deep wells plotted in figs. 11-55 to 11-57 represented data sampled 17
months apart (IB-4D on 9/3/15 and IB-3D on 2/14/17). So, in this case, the "distance" variable was
conflated with "time". Were the concentrations shown in the plots due to distance or to the passage of
time. The third of the three deep wells plotted (GWA-29D, boron is below detection) was far side -
gradient and according to potentiometric maps (fig. 6-18) appears to be recharged from water in a
"clean" upslope area not associated with the basin. So the inclusion of this well on the plot is not
appropriate. Rather, the third well, if included, should have been farther downgradient along the
contaminated flowpath (because of the terrain and proximity of the Broad River, no such well existed).
As presented, the plots incorrectly imply that contaminant levels decrease rapidly to below detection
just downgradient of the basin when, in fact, this is unlikely. Similar issues were noted for
concentration -distance plots associated with other source areas.
6. An upward vertical gradient was observed (0.2 ft in GWA-14S/D) upgradient of the basin. Although
0.2 ft is not a large difference, because it did not align with the conceptual model of downward
gradients in upslope and basin areas and upward gradients along areas of GW discharge, the CSA needs
to explain this occurrence and how it relates to GW flow in the area.
7. Soils in three borings across the basin and residual soils collected post excavation contain Sb, As, Se,
Sr, 5O4, and TI above the POG/BTV (Appendix B dataset). The CSA was inconsistent when presenting
these exceedances. For example, the report text acknowledged only As and Cr. Figure 7-2
acknowledged only As, Cr, and TI. The report did not discuss whether these soil concentrations are
impacting GW or implications for receptors.
8. Sediments sampled in six locations (Appendix B dataset) associated with the basin contain As (5
locations), Mn (1 location), and Se (1 location) above the soil POG. Although the detection limits for TI,
Sb, and Se generally were too high to evaluate exceedances, the CSA did not discuss. The CSA did not
explain how SW quality or the distribution of contaminated GW relate to these sediment findings or
implications for receptors.
9. SW samples CLFSP051 and CLFTD052 were not mapped in the CSA (but were mapped in a February
2016 risk assessment report). These samples had SW exceedances for 5O4, TDS, Al, and Co (CLFSP051
also exceeded for As). The CSA needs to discuss this and implications for CAP design.
7

10. Ecological risks were associated with the units 1-4 inactive basin (part of "area 1" in the February
2106 Risk Assessment report) and included muskrat, robin, and vole (aluminum). The CSA needs to
discuss whether there are any extenuating circumstances related to the sampling or sample locations
that may affect the implications for CAP design as part of 02L .0106 (i).
11. The CSA states that only B, Cr, Co, Mn, Sr, SO4, TI, TDS, and V are being considered for MNA in the
CAP for the units 1-4 inactive basin source area. The CSA needs to state how these and only these
constituents were selected for consideration.
ACTIVE BASIN - THE ACTIVE BASIN IS DIVIDED INTO THREE SOURCE AREAS, EACH DISCHARGING TO A
DIFFERENT RECEPTOR AREA. THE THREE SOURCE AREAS ARE REFERRED TO HERE AS "ACTIVE NORTH",
"ACTIVE WEST", and "ACTIVE SOUTH"
ACTIVE NORTH
The "Active -North" source area is defined here as that portion of the active basin that discharges
northward to the Broad River through the northern dam. As defined, this source area is about 25 acres
in size and is bounded to the south and west (approximately) by AB-4 and to the north by AB-1.
1. The source footprint (i.e. ash and saturated ash) was not well defined in the CSA. Geologic cross
section A -A' (fig. 6-2) extrapolated across a 1000 ft length between AB-4 (where ash was observed) and
the northern dam/waste boundary at AB-1 (where ash was not observed).
2. The CSA presented contradictory information about the presence of ash in the ponded area south of
the northern dam. Cross-section map A -A' (fig. 6-2) shows the absence of ash. Cross-section map F-F'
(fig. 6-7), perpendicular to and crossing A -A', shows the presence of ash in the same location. The CSA
must be internally consistent and have a rational basis for the information provided. Because ponded
conditions prevented direct observation of ash within the ponded area, the CSA needs to reference
engineering drawings and historic topographic maps to carefully determine the extent and volume of
the ash.
3. GW flow directions are uncertain in the area about 300 ft N-NW of AB-4 where GW divides and flows
either W toward Suck Creek, NW toward the western ash storage area and then to the Broad River, or N
toward the Broad River. WL observations were limited in this area. The CSA stated in general terms
throughout the report that GW "flows primarily north toward the Broad River and, in the case of the
active basin, also west toward Suck Creek." The CSA did not define the location of the GW divide
between the two areas or discuss why it matters. If it is determined that GW restoration is required in
this area, an understanding of the local GW flow directions will be needed. Specifically, the location of
the GW flow divide would need to be determined so that any proposed corrective actions for "Active
North", "Active West", and the "Ash Storage Area" are based on an accurate understanding of
contaminant movement within, toward, or away from the three source areas. All well data needs to be
utilized for WL contouring of figs. 6-15 to 6-20, and if it is determined that an additional piezometer(s)
0

are still needed to understand GW movement in the area of the divide then it/they need to be installed
and measured (WL) quickly and used as part of the CAP development.
4. The description of contaminated GW was focused mostly on simply summarizing the mapped and
tabled data. Very little interpretation was provided to explain the source of or reason for the observed
concentrations in different areas within and surrounding the Active North source area, whether of ash,
pore water, or upgradient or overlying contaminated units. A map was provided showing the upward or
downward trend of boron in most wells across the facility but this map was not actually used in any
meaningful way in discussions about local contaminant distribution and movement. Pore water was not
used to explain the downgradient concentrations and movement of contamination. Only one
contaminant cross section was mapped through the source area (A -A', figs. 11-61 to 11-75). While we
recognize that the ponded area prevented the installation of monitor wells in ideal locations, the use of
wells MW-10S/D and CCR-4D to map the migration of contamination along a cross section needs to
include an acknowledgement that these wells may not be measuring the relative heart of the
contaminant plume in the same way that AB-4 and AB-1 are expected to be.
5. The CSA shows boron -vs -time plots (figs. 11-49 to 11-51) that omitted a key and informative well
location, MW-20D. Boron has been increasing in MW-20D (from 100 to 600 ug/L) over six years, calling
into question whether concentrations of this and other contaminants will continue to increase with time
in this area of GW discharge. The well that was plotted, GWA-21D, located 200 ft to the east, shows
boron with essentially no change over a three-year period (from 150 to 137 ug/L). It would be useful to
understand why concentrations are steadily increasing in MW-20D and are much lower and unchanging
in GWA-21D located 200 ft away. Understandings in this local area need to be presented in the CSA to
support CAP design.
6. Contaminated GW from the "Active North" source area discharges to the Broad River receptor along
the compliance boundary at levels that exceed 2L/IMAC standards. This contamination will need
corrective action but the CSA maps and discussion did not indicate this clearly. For example, the iso-
concentration maps presented for shallow Fe (fig. 11-19), Mn (fig. 11-22), and Co (fig. 11-16) show
"PBTV contours" that depict where that contaminant is above background but do not make clear that
these areas, if they are at or beyond the compliance boundary, require corrective action. The same is
true of deep Fe (fig. 11-20), Mn (fig. 11-23) and bedrock Mn (fig. 11-24). The shallow V PBTV contour is
not shown at all in fig. 11-37 even though shallow V is above the PBTV (e.g. GWA-22S) and requires
restoration. The deep V PBTV contour is not shown at all in fig. 11-38 even though deep V is above the
PBTV (e.g. GWA-22BRU) and requires restoration. The CSA needs to clearly define the areas (and flow
units) and contaminants in need of corrective action pursuant to 02L .0106. Unless data to the contrary
are provided and explained in the report, the exceedance contours need to be open to the Broad River
for all flow units. All existing data need to be used for isoconcentration mapping, including MW-11DA
and MW-11D, and all additional wells needed to understand contaminated GW conditions should be
installed and sampled prior to the development of the CAP for this area, including MW-11BRO, and AB-
1BRO.
7. The CSA does not mention or account for the fact that an historic channel (Suck Creek) existed in the
centerline of the active basin prior to Duke's channelizing and re -directing the flow away from the
current footprint of the active basin in order to construct the active basin. This is a problem because the
remnant channel, to some extent, would be expected to result in preferential pathways in the shallow
0

and (or) deep system that would not otherwise exist and, judging from the report, this issue has not
been considered. Site conditions (WLs, Ks, boron concentrations, vertical gradients, etc) need to be
evaluated to determine what affect the remnant channel has on contaminant movement from the
"active north" and "active south". The goal is to understand its effect and account for it as needed in
the CAP design. If additional data would help discern the effects then this data needs to be collected
and evaluated during preparation of the proposed remedy for each source area.
8. Soil beneath the ash was sampled in only one location (AB-46R, 44 ft bls) within the 25-acre source
area.
9. On page 12-7, the report states that "This update to the human health and ecological risk assessment
supports a risk classification of "low" for GW related consideration". It is not clear how the CSA arrived
at a low risk. The CSA needs to clarify on what regulatory or technical basis a "low" risk classification
was suggested and why this is suggested for the facility as a whole rather than individual source areas
each of which will require a closure plan.
10. The report (p. 15-14) states that Co, Fe, Mn, and Sr are being considered for an MNA CAP for this
source area. The CSA needs to state how these and only these constituents were selected for
consideration.
11. An assessment is needed of the potential impact on the leaching of saturated ash due to river stage
fluctuations and (or) GW level fluctuations.
ACTIVE WEST
The "Active West" source area is defined here as that portion of the active basin that discharges
westward to Suck Creek in the area of the dam to Suck Creek. As defined, this source area is about 14
acres in size and, in very general terms, is bounded to the south by CCR-14D, to the east by AB-3, and to
the north by CCR-8. This source area is somewhat unique because its compliance boundary extends
beyond a major SW drainage feature — Suck Creek — that is a Class WS-IV water of the state. So while
GW contamination may or may not extend beyond the compliance boundary in this area due to this SW
feature, contaminated GW discharge to Suck Creek must not cause exceedances of the SW standards for
certain corrective actions to be allowable.
1. The source footprint (i.e. ash and saturated ash) was not well defined in this area. The E-W geologic
cross section KX (fig. 6-12) used to show where the ash and saturated ash are located spans a distance
of approximately 800 ft through the waste boundary here but includes only two borings that contain
ash. The two borings — at AB-2 and AB-3 — are separated by about 600 ft.
2. Although a large cell of ash (reportedly 300,000 cubic yards) was moved from the southern portion
of the active basin to this Active -South Dam source area, the CSA only mentioned it in passing with a
sentence (p. 3-2. The CSA did not map its location nor describe any details. Movement of this massive
volume of ash would be expected to impact GW contaminant concentrations in time and space in and
10

downgradient of the area', information that would be very valuable to modeling efforts and CAP design
as it is a fully monitored example of waste/plume evolution in time and space.
3. Contaminated GW4 occurs in numerous shallow and deep wells adjacent to the dam at Suck Creek.
GW flow here is from the ash basin towards Suck Creek, a perennial stream. However, based on
shallow, deep, and bedrock potentiometric contours (shown in figs. 6-16, 6-18, and 6-20, respectively),
contaminated GW appears to at least partially underflow the creek and move toward the higher order,
more distant Broad River (a condition that is not surprising in the Piedmont -Mountain Physiographic
Province). No mention of underflow or its potential is made in the CSA. Instead, the CSA seems to
suggest that all contaminated GW from the eastern side of Suck Creek discharges to Suck Creek, and all
GW from the western side of Suck Creek also discharges to Suck Creek. This is a limited read of site
conditions according to the potentiometric maps and vertical gradient data near Suck Creek here'.
4. WL was not measured in anywhere along Suck Creek during the synoptic round of WLs used to
create the potentiometric maps. This is an important omission and limits the understanding of GW
movement at the very local scale along the creek. This is important because any proposed remedy, if
needed, must be based on an understanding of local contaminant flow directions and where the
contaminants are discharging (local stream or more distant river). To help assess flow conditions along
Suck Creek, boron concentrations in this area need to be evaluated (both sides of Suck Creek), and an
additional well nest installed about 200 ft NW of SW-SC-S.
5. The description of contaminated GW was focused mostly on simply summarizing the mapped and
tabled data. Very little interpretation was provided to explain the source of or reason for the observed
concentrations in different areas within and surrounding this source area, whether of ash, pore water,
or upgradient or overlying contaminated units. One contaminant cross section map was provided for
this 14-acre area (K-K', figs. 11-91 to 11-105) and it showed concentrations of boron in the deep unit
near the dam to Suck Creek but much lower concentrations in shallow and deep GW immediately
upgradient. No explanation was provided for the source or origin of the deep boron. Pore water was
not used to explain the downgradient concentrations and movement of contamination.
6. It appears that GW near the dam to Suck Creek has a component of flow to the NE (roughly parallel
to the dam) based on the 3 ft difference in shallow WLs measured between MW-8S (-730 ft asl) and
GWA-20S (-727 ft asl) located about 75 ft away. The potentiometric maps in Figs. 6-16 and 6-18 do not
reflect this. This is important because there is a lack of shallow and deep wells to the NE, and lack of
bedrock wells in general, which limits the ability to understand GW contamination and movement in and
from this area. While this area is within the compliance boundary, contaminated GW discharge may not
3 Contaminated GW increases are seen in certain wells (e.g. CLMW-1) downgradient of the "new" ash location.
4 Examples include CCR-91D (B = 1020, SO4 = 594, TDS = 940); MW-81D (Fe = 33,400, Mn = 5360); GWA-39S (B =
1620, Co = 31.7, Fe = 22,300, Mn = 6310, V = 3.3); include GWA-20D (B = 817, Co = 81, TI = 0.57); etc. Note that
GWA-20S has much lower boron suggesting that a deeper flowpath may be transporting the bulk of contamination
here.
S A relatively minor downward vertical gradient of 0.2 ft/ft was measured at well nests MW-8S/MW-8D and GWA-
20S/GWA-20D beside Suck Creek that show a slight downward gradient from the shallow to the deep flow system.
11

cause 2B exceedances for certain corrective actions so an understanding of contaminant conditions in
this area is needed.
Only one bedrock well (GWA-20BR) is positioned to assess contamination in or just downgradient of this
area and it contains boron at 257 (meaning that ash leachate is migrating at depth) along with 2L
exceedances of Fe and Mn. Only one deep well (and no shallow well) is positioned in the downgradient
NE direction (CCR-9D), and it contains 2L exceedances for B, SO4, and TDS (data for other COls were not
reported for this well so exceedances could not be determined). The horizontal extent of shallow and
deep contamination and to some extent bedrock contamination to the NE has not been defined here.
Potential underflow of contaminants may be monitored partially by wells on the western side of Suck
Creek, which include GWA-33S/D/BR (shallow unit Co, Fe, and Mn 2L/IMAC), GWA-43S/D (shallow V
exceeds 2L/IMAC), and GWA-42S (all reported Cols appear to be below 2L/IMACs). However, the
positioning of these wells does not account for flow that appears to be moving in a more northerly
direction. It is recommended that a nested set of wells be installed and sampled on the eastern side of
Suck Creek N-NE of CCR-91D and a nested set of wells on the western side of Suck Creek about 200 to 300
ft north of GWA-42S; it is recognized that the terrain is rugged along Suck Creek in this area so this fact
would need to be considered when choosing the location. (GWA-40S and AB-213RO were both missing
from the master dataset provided in Appendix B and from the WL maps in the report figures and from
the mapped depiction of shallow boron contamination; and well GWA-39S (boron = 1620 ug/L) was
missing from the boron map. If an appropriate well nest location is not possible due to problems with
drill rig access, the project team needs to discuss an alternate approach to understanding the extent of
GW contamination and its movement from this area. The goal should be to first determine the extent of
the problem and whether GW restoration is needed in this area. If it is, a better understanding of local
conditions will be needed for CAP design, including understanding and defining the horizontal extent of
shallow and deep contamination in this area, the local GW flow directions, and the extent to which
underflow of Suck Creek is occurring and the expected discharge location of any underflow.
7. The CSA states that Co, Fe, Mn, and Sr are being considered for MNA in the CAP for the Active West
source area. The CSA needs to state how these and only these constituents were selected for
consideration.
8. An additional "21--213" surface water sampling location is needed approximately 150 ft downstream
of SW-SC-6 to account for the GW flow directions inferred by the potentiometric mapping in fig. 6-16.
Sampling and analysis should be carried out as outlined in the report titled "SW Sampling to Assess 15A
NCAC 2B Compliance for Implementation of Corrective Action Under 15A NCAC 02L .0106" (Synterra,
March 2017).
9. An assessment is needed of the potential impact on the leaching of saturated ash due to creek stage
fluctuations and (or) GW level fluctuations.
ACTIVE — SOUTH
The "Active South" source area is defined here as the southernmost portion of the active basin that
discharges to Suck Creek in the area west of GWA-47D and GWA-27. This area of GW discharge to Suck
Creek is farther south than the area referred to as "Active West" that discharges along the southern
12

dam to Suck Creek. As defined, this source area is about 15 acres in size and, in very general terms, is
bounded to the south by CLMW-6, to the east by a location just west of AB-5, and to the north by a
location about 200 ft south of AB-3. Like source area "Active West", this source area is somewhat
unique because its compliance boundary extends beyond a major SW drainage feature — Suck Creek —
that is a Class WS-IV water of the state. So while GW contamination may or may not extend beyond the
compliance boundary in this area, contaminated GW discharge to Suck Creek must not cause
exceedances of the SW standards for certain corrective actions to be allowable.
1. The geology is not mapped in this area. No geologic cross section is provided. Based on boring logs,
the areas near GWA-27DA and CCR-15D appear to have no shallow flow unit due to pinch out, and only
the deep and bedrock units exist here. However, the potentiometric maps in figs. 6-15 and 6-16 do not
reflect this fact. The shallow potentiometric maps depict WL contours in this area which is not possible
if the unit does not exist. Geologic mapping, contaminant cross section mapping, and corrected
potentiometric mapping is needed for this source area and needs to include geologic and contaminant
information from locations at CLMW-6, AB-6, CCR-16, GWA-27, and others as appropriate.
2. The GW flow direction is unclear near GWA-271DA, CCR-14D, and CCR-13D where, based on
topography, movement would appear to be either to the NW toward the dam at Suck Creek or to the
SW directly to Suck Creek. The potentiometric contours in fig. 6-18 are too widely spaced to understand
the direction of local GW flow here. A number of deep wells were not measured during the synoptic WL
event in Feb 2017 (e.g. GWA-461D, MW-7D, and GWA-27D). The use of all deep wells would have
provided a better understanding of GW flow directions in this area. This is particularly important since
the shallow flow system apparently does not exist here and since this area is near the current ash sluice
discharge to the active basin. It is also important because several wells in this vicinity (along the crest)
contain 2L/IMAC exceedances (e.g. CCR-15D CAMA contains Mn at 114; GWA-27D contains B at 939, Mn
at 1430; GWA-27DA contains B at 927, and Mn at 1350) that may be migrating to the compliance
boundary west of this area. Because of the steep terrain, wells are not installed near the compliance
boundary and adjacent to Suck Creek in this area. The direction of deep GW flow in this area will affect
any remedial design that may be needed here. A synoptic round of WL measurements need to be made
in this area using all wells.
3. Boron concentrations in GWA-47D have been increasing since the well was installed in April of 2016.
GWA-47D is located just west of the southwestern extent of the active basin The CSA does not discuss
this or whether these concentrations are expected to increase above 2L/IMAC standards.
4. Boron concentrations in pore water well AB-6S have fluctuated sharply up and down with each
sample event (range is 11,300 to 2140 ug/L). The CSA does not discuss why this is occurring or whether
it has implications for the understanding of other pore water concentrations in general across the site.
5. While seeps are covered under a temporary SOC, the data associated with them is very useful in
determining contaminated GW occurrence and movement. Seeps 528, 5-29, 5-30, 5-31, 5-32, and 5-36
all contain elevated boron (1210 to 1600 ug/L) but were not discussed in the CSA.
6. An assessment is needed of the potential impact on the leaching of saturated ash due to creek stage
fluctuations and (or) GW level fluctuations.
13

ADDITIONAL SPECIFIC COMMENTS ON THE CSA UPDATE REPORT (SYNTERRA, 2018)
1. Section 1.5 (Previous Submittals) on p. 1-7 lists the four reports submitted to date for Cliffside. For
completeness, this section should also reference and include in an Appendix the review comments
provided by the Division for these documents.
2. Additional details on individual source areas are needed. Sections 2.0 (Site History and Description)
and 3.0 (Source Characteristics) describe information related to each source area, but the information
lacks details and specificity. Page 2-2 states that "This ash storage area was probably created when ash
was removed from the active ash basin....", and "The eastern portion of the ash storage area maybe a
spoils area.....". It is expected that as -built drawings, historic topo maps, and disposal records be used to
define and map the expected extent, depth, and volume of ash and saturated ash at each individual
source area.
3. On p. 3-9, the report states that SPLP testing was conducted on ash from six locations but no details
were provided. Results were generalized but were not linked to individual basins, well IDs, or sample
depths. Need discussion, by source area, of results, spatial variability, and comparison to downgradient
contamination.
4. The chemistry of ash pore water was not evaluated by source area for spatial and temporal variability
or compared to downgradient contamination. On p. 3-10, the report stated vaguely that "The pore
water sampling results show fluctuating concentrations for some constituents in some wells" but details
(well IDs, basins, etc) were not provided. Need discussion, by source area, of pore water results, spatial
variability, and comparison to downgradient contamination.
5. For the active basin, it is expected that the dynamic nature of ash and stormwater input to the basin
be discussed along with any re -location of large amounts of ash from or within the basin (locations,
amounts, timing). One sentence was provided (p. 3-2) to describe the movement of a large amount of
ash from one location to another location within the active ash basin; details were not provided.
6. Page 2-6 states that "Information to date indicates that the thickness of soil impacted by ash would
generally be limited to the depth interval near the ash/soil interface" but no reference or basis for the
statement is provided. Need basis (data, locations) for the statement.
7. The amount of ash in each source area was estimated (p. 3-2, 3-3, 3-4) but the basis for the
estimates was not provided. Need basis for estimates. In addition, the amount of ash was stated in
terms of "tons" at the active basin, unit 5 basin, and units 1-4 basin, but was stated in terms of "cubic
yards" at the ash storage area. Please explain the difference in units.
8. Section 2.3 (CAMA-related Source Areas) on p. 2-5 omits the raw coal piles as a source area.
9. The active ash basin is divided into two source areas (south dam area and north dam area) but needs
to be divided into three source areas (active N, active W, and active SW) due to different discharge areas
into which each flows.
10. On page 2-7 the report states that "an area of exceedances was identified that appears not to be
associated with the CAMA-related source areas. This area is located east of Unit 6 and west of Suck
14

Creek." Because this area may contain CCRs that intermix with CCR contamination at Units 1-4 basin, it
needs to be assessed as its own source area and on schedule with the upcoming CAP. It is requested
that assessment sampling locations be proposed by letter within 14 days of receipt of these comments.
11. Section 4.0 (Receptor Information) states that "The dams contain engineered drainage features
associated with dam drainage and stability. These features are internal or adjacent to the dams and are
not included in the underground utility mapping." Need mapping of any features that are saturated.
12. Page 4-4 states that "Several surface water bodies that flow toward the Broad River were identified
within a 0.5-mile radius of the ash basin pre-2017 compliance boundaries." The specific number of
surface waters needs to be stated, and a map depicting these surface waters needs to be provided and
referenced in this section.
13. Unsubstantiated statements were used to make the case that local supply wells have not been
impacted by coal ash. For example, the CSA states on page 4-9 that "The water chemistry signature of
the water supply wells with available water chemistry data is similar to the background bedrock well
data at the Site, indicating that these wells reflect natural background conditions." On page 12-7, it
states that "there are no indications that potential risks to off -site residences exposed to groundwater
exist". On page 14-24 it states that "these [private supply] wells reflect natural background
concentrations..." On page 12-6 it states that "Recent (2016-2017) analytical results from off -site water
supply wells indicate that constituent concentrations are less than 2L or less than PBTVs for site
groundwater, with the exception of four vanadium detections". However, the Appendix B table shows
many more exceedances6. On page 14-24 it states that "these [private supply] wells reflect natural
background concentrations..." Need discussion that consolidates information needed to make the case
that private supply wells are not impacted by CCR (see General comment 30).
14. Page 4-8 states that "downgradient bedrock monitoring wells GWA-21BR and MW-20DR.... plot
along with background wells BG-1BR, MW-24DR, and MW-32BR indicating these downgradient wells are
likely representative of unimpacted groundwater within the bedrock flow layer." This interpretation is
incorrect. These wells are not "unimpacted" (GWA-21BR has boron at 100 ug/L and MW-20DR has
boron at 170 ug/L). If boron in a well is present above its BTV, the well is not "unimpacted" by coal ash.
This comment applies to all wells across the facility.
15. Page 4-9 states that "A more thorough evaluation of Piper diagrams related to ash pore water,
downgradient groundwater, and background conditions is provided" in a later section of the report. It
would be more effective to place all Piper narrative in one section of the report when making the case
that pore water, downgradient well water, and supply wells have unique signatures.
16. Section 4.5 (Surface Water Receptors) on p. 4-9 refers to surface waters at the Cliffside facility in
general, and does not discuss the surface waters that receive discharge from specific individual source
areas. Need surface water mapping by source area along with an indication of the SW classification of
each surface water. Section 4.5 refers to NC SW standards but does not reference the table (Appendix
6 Many of the exceedances are for wells sampled in 2014 or 2015 which also need to be considered. A total of 26
supply wells could not be assessed for vanadium due to a lab detection limit above the vanadium IMAC/BTV. One
well exceeded the BTV for strontium. And four wells exceeded the 2L/BTV for manganese.
15

B) in which SW results are presented. The table in Appendix B shows SW standards, but some of these
are incorrect. Aluminum, strontium, antimony, cobalt, thallium, and sulfide have SW standards that
must be met under 2B rules. Standards for the other constituents need to be re -checked for accuracy.
17. Page 5-3 states that "Within a [drainage] basin, movement of groundwater generally is restricted to
the area extending from the drainage divides to a perennial stream (LeGrand, 1988), and "Rarely does
groundwater move beneath a perennial stream to another more distant stream..." And p. 5-4 re -states
this concept by describing the groundwater system as a "two -medium system restricted to the local
drainage basin." And later, on p. 5-4 the concept is re -stated again by describing that "in natural areas,
groundwater flow paths in the Piedmont are almost invariably restricted to the zone underlying the
topographic slope extending from a topographic divide to an adjacent stream." This conceptual
understanding does not match the potentiometric contours shown in figs. 6-16, 6-18, and 6-20 that
strongly suggest partial underflow of Suck Creek locally. Partial underflow of lower order streams
toward higher order streams is not uncommon in the Piedmont and Blue Ridge settings. This
discrepancy between site data (potentiometric maps) and theoretical conceptualizations need to be
discussed as it has a direct bearing on understanding contaminant transport from the active basin.
18. Page 6-1 states that "Typically, mildly productive fractures (providing water to wells) were observed
within the top 50 feet of competent rock." Discussion is needed to define "mildly productive" and to
describe the data and well IDs used to arrive at this conclusion. Page 6-1 also states that "The bedrock
flow layer ....is characterized by the storage and transmission of groundwater in water -bearing
fractures." Because competent bedrock fracture apertures commonly are relatively thin, the storage
capacity tends to be very low compared to the storage in the overlying porous saprolite and transition
zone material. As a result, bedrock fractures tend to be conduits rather than storage reservoirs. This
conceptual understanding is important to understanding contaminant transport.
19. Groundwater flow directions need to be accurately conceptualized at each source area separately.
Page 6-1 states that "The CSS ash basins act as bowl -like features toward which groundwater flows.
Groundwater then flows from the basins...." This description is unclear. At the active basin,
groundwater tends to flow toward the basin from the east and south, and away from the basin toward
the west and north.
20. Page 6-3 states that "Fill was used in the construction of dikes and as cover for ash storage areas."
Areas and depths of fill need to be mapped where known.
21. Page 6-6 states that "The dip direction of the foliation cannot be determined from the borehole
data." Discussion is needed about how this affects the understanding of contaminant transport in
individual source areas. Page 6-6 also states that "Data from rock cores also show two predominant
joint sets; a 40- to 50-degree dipping set and a horizontal to sub -horizontal set." Which rock cores? The
report needs to state well IDs and a map. Discussion is needed about how this affects the
understanding of contaminant transport in individual source areas.
22. Page 6-7 states that "The similarities in extent of saprolitic depths at boring locations and
mineralogical composition suggest uniform regolith conditions across the Site." Which specific locations
are being referred to here? This conclusion runs counter to other sections of the report that suggest
varying thicknesses of saprolite across the facility (e.g. saprolite was not encountered in the SW area of
the active basin at locations CCR-15D and GWA-47D). Need discussion of saprolite by individual source
16

area rather than by facility. Discussion needs to focus on the local stratigraphic factors that affect
contaminant transport along "hot" flow paths.
23. Page 6-8 summarizes the major structures observed during geologic outcrop mapping, and five
commonly occurring joint sets (strike and dip) were noted. Page 6-8 states that "The significant
structure with respect to groundwater movement include the joint sets .... that were observed to be very
continuous and crosscutting of fold structures and fractures that have formed along foliation in brittle
(pressure and temperature) conditions." Need discussion of how these outcrop observations relate to
the geology in individual source areas and how it affects contaminant transport in key areas of concern.
24. Page 6-9 states that "Two major factors that influence the behavior of groundwater in the vicinity
of the Site include the thickness (or occurrence) of saprolite/regolith and the hydraulic properties of
underlying bedrock." Page 6-9 also provides a paragraph that generalizes saprolite thicknesses across
the facility. Given that these are major factors, need saprolite mapping at each source area and a
discussion of how these effect contaminant transport locally at each source area.
25. Page 6-10 states that "Generalized cross -sections are presented in Figures 6-2 through Figure 6-14
showing site geology and groundwater flow directions." Many of the flow directions shown on these
cross sections are in error and need to be corrected.
26. A discussion of ash pore water was presented on p. 6-10 but included few or no new details. Seven
borings were made within the waste boundary of the active basin but only four contained ash. Three of
four borings in Units 1-4 basin encountered ash. Two of eight borings at the Unit 5 basin encountered
ash. And two of five borings at the ash storage area encountered ash. Need discussion about whether
these small number of borings that encountered ash are sufficient to adequately describe the source
and its pore water variability in each of the individual source areas. Need discussion about whether the
ash that was encountered in each of the source areas was of the approximate depth and thickness that
would be expected based on historic topographic mapping, as -built drawings, and disposal records.
27. Page 6-12 presented a broad discussion of groundwater flow directions but included few details.
Groundwater flow directions need to be understood locally at each source area. Where a local
groundwater divide occurs and splits the contaminant flow toward different discharge areas (e.g. the
area N-NE of AB-3), its location needs to be mapped. Areas in need of additional wells or WL
measurements need to be discussed. The goal should be a detailed understanding of local flow
directions in all three flow units (S, D, and BR) from the source across the waste boundary to areas of
discharge. As requested in prior comments to Duke, large scale maps are most effective for local
potentiometric mapping, and they need to contain superimposed 2 ft topographic contours,
measurements made in selected surface water locations (e.g. near the dam at Suck Creek), and
measurements made at ALL existing monitor wells.
28. Page 6-13 and 6-14 presents average hydraulic gradient values for selected shallow, deep, and
bedrock wells. It is unclear how the wells were selected for use in calculations and in the averaging.
Very basic observations were noted such as areas of higher relief had higher hydraulic gradients. A
much more relevant and useful analysis would be to a) compute hydraulic gradients along segments of
"hot" flow paths in individual source areas, b) repeat the computation for each flow unit (S, D, and BR)
and compare them, and c) compute vertical gradients between S/D and D/BR units at well nests along
17

these segments. This would help provide an understanding of contaminant transport characteristics in
"hot" areas of the site.
29. Page 6-14 also presents average vertical gradients for selected pore water to shallow wells, shallow
to deep wells, and deep to bedrock wells. Again, it is unclear how the wells were selected for use in
calculations and in the averaging. One observation was that upward gradients were noted in upgradient
background locations (MW-24 and BG-1). This observation runs counter to the conceptual model
(downward gradients in upslope areas and upward gradients in discharge areas) but was not discussed
or explained. Need discussion for locations that do not follow the conceptual model. Need discussion
of the significance of a 0.2 ft vertical gradient.
30. Page 6-15 presents geometric means of hydraulic conductivities computed from shallow, deep, and
bedrock wells. Values were lowest for the transition zone which runs counter to statements on page 5-2
and on page 5-3 in which the transition zone is identified as the most transmissive, not the least.
31. Page 6-15 also states that "These measurements reflect the dynamic nature of the transition zone,
where hydrologic properties can be heavily influenced by the formation of clays and other weathering
by-products." Need discussion about how this affects contaminant transport locally and implications for
corrective action design.
32. The report states (p. 6-16) that "primary porosity is negligible" when referring to contamination in
the bedrock unit. While this may be true, the report provides no basis for this statement. This will be a
fundamental assumption in a CAP design and needs to be substantiated in the CSA.
33. The GW flow directions shown on the geologic cross sections in figs. 6-3, 6-5, 6-7, 6-8, and 6-13
were incorrect and thus inadvertently misleading.
34. Section 7.2 (Facility Soil Data) states that the soil beneath ash was collected in three locations
within the active basin, 3 locations within the units 1-4 basin, 1 location within the unit 5 basin, and 2
locations in the ash storage area. Need discussion about whether this density is adequate (especially
given the variability of ash and pore water conditions within each of the waste boundaries). Need
discussion, for each source area, to cite the specific boring/well IDs and depths where exceedances of
POG and BTVs occurred and whether these exceedances appeared to be linked in any way to
groundwater contamination downgradient. The exceedances need to be formally identified as a
"secondary source" and mapped accordingly.
35. Section 7.2 (Facility Soil Data) also states that soil outside the waste boundaries was sampled at
various downgradient locations. Results were presented generically without identifying boring/well IDs
and depths. Need discussion by source area of specific locations that exceeded the POG and BTV and
why. Discuss implications or appropriateness of defining these locations as secondary sources.
36. Section 7.4 (White Material at Toe of Unit 5 Inactive Ash Basin Dam) stated on p. 7-9 that "the
white material was consistently observed and noted in reports from September 11, 2014 to July 21,
2015, with the exception of the January 28, 2015 and February 19, 2015, reports in which the white
material was not observed. Need discussion about why (cause) the substance appeared, why it
disappeared on certain dates, whether lab tests determined that it exceeded the POG and BTV, and
implications for groundwater contamination and 2L compliance.
18

37. Page 8-1 states that "Sediment sample locations are shown on Figure 2-10. However, 9 of the 34
locations were not shown on the figure (or any figure). These correspond to the NCDENR March 2014
sample locations. The map needs to be revised to include the locations. The information in this section
intermixes all source areas. The sediment locations associated with a specific source area need to be
grouped accordingly. It was noted that several locations had a CCR contaminant that exceeded the soil
POG and soil BTV. Discussion is needed about a) the cause of these exceedances, b) their being a
secondary source, c) what they mean for risk, 2L/213 compliance, and remediation, and d) whether
additional sampling is needed and, if so, where.
38. Page 8-6 Section 8.2 (Sediment in Major Water Bodies) states on p. 8-6 that "Sediment samples
have not been collected from the Broad River." Sediment sampling needs to be conducted adjacent to
the unit 5 basin, coal piles, units 1-4 basin, ash storage area, and north end of the active basin and near
the monitor well containing the greatest CCR contamination.
39. Page 9-1 states that surface water was collected from ponded water within the active ash basin.
Depth of sampling needs to be provided here along with an acknowledgement that CCR concentrations
tend to increase with depth (proximity to the ash itself).
40. The section titled "Suck Creek and Broad River Sample Locations" on page 9-2 provides ALL sample
locations along both water bodies with no indication of which samples pertain to which source area.
Because corrective action is source area specific and dependent upon whether contaminated
groundwater is impacting surface water, it is important to understand which samples are associated
with which source area. Need sample locations grouped by source area.
41. Page 9-3 states that "The results of the sampling indicated that at most locations downgradient
and/or adjacent to the ash basins, constituent concentrations, where detected, are consistent with
results from background locations". The use of the word "most" needs to be revised to make the
statement specific and definitive; were surface water standards exceeded and if so, to what extent and
why?
42. Page 9-4 states that "The results of the sampling indicated that, generally, at downgradient
locations and/or locations adjacent to the ash basins, constituent concentrations, where detected, are
consistent with constituent concentrations from background locations". The use of the word
"generally" needs to be revised to make the statement specific and definitive; were surface water
standards exceeded and if so, to what extent and why?
43. Page 9-5 states that "Analytical results with the dissolved phase concentrations greater than the
associated total reportable concentrations are not included in the assessment as they are considered
invalid". Need discussion about the specific locations where this occurred, what constituents and values
were observed and whether the values exceeded surface water standards, why it may have occurred,
and whether re -sampling was conducted and if not, why not.
44. Section 9.2 (Discussion of Results for Constituents Without Established 213) did not include
standards associated with EPA criteria that are used by the Division in surface water quality
determinations. This section and all assessment of surface water results need to be revised to include
the EPA criteria values. (See NC surface water standards website link or contact ARO.)
19

45. Need surface water results presented in a table by source area. All relevant standards need to be
shown in the table along with the stream classification associated with the sample location.
46. Page 9-10 states that "dissolved oxygen, dissolved cadmium, and hardness are the only 2B
exceedances reported downstream (SW-BRAB-1, SW-BRAB-2, and SW-BRAB3) in samples collected from
the Broad River." Need discussion about the implications of these exceedances on corrective action (by
relevant source area) and potential follow up sampling.
47. Page 9-10 also states that "Based on the available data for the upstream and downstream Broad
River samples, the CSS ash basins and ash storage area are not the source of 2B exceedances in the
Broad River." Need a more focused discussion to justify this statement as it appears that the data as
presented may not support this conclusion.
48. Page 9-11 states that "Surface water sample locations SW-BRAB-2 and SW-BRAB-3 are located
immediately downstream of the permitted NPDES outfall 002..." Need to discuss what is meant by
"immediately downstream" and whether constituent concentrations were higher in SW-BRAB-3
(furthest downstream) than SW-BRAB-2 and, if so, why. Page 9-12 states that the water chemistry of
SW-BRAB-3 "is similar to the water chemistry results of ash pore water and may be representative of
mixing with the permitted NPDES discharge upgradient of this location." No mention is made of SW-
BRAB-2 - which is closer to outfall 002 - and would thus be expected to be even more like the water
from outfall 002 than SW-BRAB-3. Also need to discuss why outfall 002 was not sampled on the same
day and for the same constituents as SW-BRAB-2 and SW-BRAB-3 as this would provide much more
definitive information on which to draw conclusions (SW-7, serving as a surrogate for conditions at
outfall 002, is a sample from quiescent pond water and may not be representative of conditions at the
highly aerated outfall itself).
49. Page 9-12 states that "downstream samples SW-SC-2 through SW-SC-6 plot with higher relative
concentrations of major water chemistry ions chloride and sulfate. The water chemistry type of these
samples may indicate potential mixing from source water impacted groundwater". Need discussion
here of other CCR indicators such as boron concentrations in these surface water samples (and in
background surface water).
50. Page 10-1 states that a separate table is provided for the CCR monitoring network. It is requested
that all groundwater data be included in ONE table so that the project team does not have to flip back
and forth among different tables to access groundwater contamination data.
51. Page 10-1 states that "the results have been marked to indicate data points excluded based on a
measured turbidity greater than 10 NTUs; high PH values that may indicated possible grout intrusion
into the well screen; and data that may be autocorrelated because it was collected within 60 days of a
previous sampling event." 105 individual monitor wells (a total of 335 samples) are in this category and
were omitted from further consideration. Need a list of wells and sample events that were excluded
from CSA use and an indication of which of those wells have been replaced. Need a map showing any
wells for which zero data were available. For any wells not replaced need discussion to explain why, the
site -specific information being forfeited as a result, and implications for understanding 2L compliance
and contaminant transport (include well IDs and contaminants). Need discussion about whether
dissolved concentrations may be used as a lower bound surrogate for turbid samples and include
20

comparisons of dissolved versus total concentrations in several well locations across the facility,
including locations with a replacement well.
52. Page 10-1. Autocorrelated data need not be used in statistical tests but may and should be used for
all other analyses and interpretations. All wells need to be used to interpret boron results regardless of
turbidity or pH issues.
53. Section 10.1 (Background Groundwater Concentrations) presents PBTVs. Final BTVs have been
determined since the report was submitted and need to be used to assess contamination and 2L
compliance.
54. Page 10-6 states that PBTVs were determined for 10 constituents that do not have a 2L standard or
IMAC. The list did not, but needs to, include Sr and Mo.
55. Page 10-7 states that "The wells are not screened within the ash and are therefore not considered
pore water wells; however, due to their location within the ash basin waste boundary they are not
categorized and evaluated as downgradient wells as the constituent concentrations reported in these
wells are expected to be more representative of ash basin water than downgradient groundwater
conditions." If the wells are not screened in ash they represent groundwater conditions and need to be
understood, evaluated, and discussed accordingly. These wells need to be used to understand how pore
water impacts groundwater as it moves away from the source. Need discussion, by source area, about
how pore water is impacting groundwater in these and (other) downgradient locations. Whether these
wells need to be used to assess 2L compliance depends on the presence or location of a compliance
boundary.
56. Page 10-20 states that certain shallow downgradient wells are characterized by sodium -calcium -
chloride to sodium -calcium -sulfate water chemistry. The report goes on to state that boron
concentrations were less than 700 ug/L for all but one of those locations. Aside from determining 2L
compliance, it is unclear why 700 ug/L is thought to be significant. Boron is a good tracer of CCR
contaminated groundwater, whether or not the level is above 700. Need discussion that describes the
understanding of plume evolution (contaminant transport) from source inside waste boundary to
downgradient-most wells. Discussion might include water type (Piper), sources of clean, contaminated,
or mixed recharge water, boron concentrations, and other factors that describe why contamination
occurs in some areas and not in others. The discussion needs to be divided by the three source areas
within the active basin (Active North, Active West, and Active South), each of which has a different and
unique plume evolution.
57. Page 10-20 states that "the unique water chemistry signature and the lack of boron detection [at
AB-4D] may indicate groundwater beneath the basin in the deep layer is unimpacted". The data suggest
that this conclusion is overstated and needs to be narrowed to specific areas where the deep layer
appears to be unimpacted. For example, deep groundwater is clearly impacted by CCR (with boron at
about 900 ug/L) just downgradient of the basin at GWA-27D and CCR-14D, an area where no overlying
saprolite exists (which may have been a potential source of boron for the deep unit). Also, deep
groundwater is impacted by CCR at the edge of the waste boundary at AB-1D (B = 610 ug/L), an area
where shallow groundwater, which may have been a potential source of boron for the deep unit, had no
detectable boron. A close look at concentrations along the western edge of the active basin pond
suggest that conditions vary locally and likely are dependent upon local groundwater directions and
21

local permeability of the flow units. For example, CCR-6D, CCR-5D, MW-10D, and CCR-4D, all drilled in
the deep unit near the western edge of the pond, had highly variable boron of 1190 ug/L, 93 ug/L, 163
ug/L, and 50 ug/L, respectively. It is unlikely that the deep unit beneath the active basin is unimpacted
across the entire waste boundary, rather it is unimpacted in certain local areas. This is an important
point for purposes of understanding contaminant transport downgradient and corrective action design.
58. Page 10-20 lists nine bedrock wells that are characterized as Ca-K-HCO3 type water consistent with
background bedrock groundwater and that have boron less than 700 ug/L (five were less than 50 ug/L).
Based on this, the report concluded that this "indicates bedrock groundwater at these locations is
unimpacted by source groundwater." This statement is incorrect. Any location with boron above
background should be understood to be impacted by CCR contamination whether or not its water type
is consistent with background wells. For example, boron is found in several of the bedrock wells listed,
including GWA-21BR (102 ug/L), MW-20DR (142 ug/L), GWA-27BR (210 ug/L), and GWA-20BR (257
ug/L). Need revised and detailed discussion about where the bedrock unit is impacted by CCR and its
likely origin based on the presence, thickness, and level of contamination of flow units between the
impacted bedrock and the source. This is needed to understand contaminant transport downgradient
and corrective action design.
59. Pages 10-21 to 10-23 provide assessments and conclusions of impact in other source areas based
on water types and boron above or below 700 ug/L. Need revised and detailed discussion, by individual
source area, about where impacts occur based on both water type and boron below 700 ug/L.
Discussion needs to include a) locations (well IDs) with a CCR water type (e.g. Ca-SO4-0) but no boron,
b) locations (well IDs) with background water type (e.g. Ca-HCO3) and moderate boron levels, and c)
why these apparent anomalies occurred. Discussion needs to also include the likely origin of the CCR
contamination based on the presence, thickness, and level of contamination of flow units between the
impacted well and the source. This is needed to understand contaminant transport downgradient and
corrective action design.
60. For each source area, consider providing a map of locations with "no apparent CCR impacts" based
(only) on an evaluation of boron concentrations and water type. This would help provide an
understanding of the occurrence and transport of high concentrations (above 2L/IMAC/BTVs) of
geochemically-mediated COls and how those relate to areas of obvious CCR impacts and areas of
questionable CCR impacts. It would be especially valuable to superimpose a color -shaded
isoconcentration map of pH and Eh ranges across each source area. The purpose is to understand the
factors that led to elevated levels of geochemically-mediated COls across a given source area, levels that
make occur in isolated pockets. This discussion and mapping could be included in the geochemical
model report.
61. Page 10-28 states that "All of the private water supply wells are upgradient and the reported
exceedances likely reflect natural variations or local groundwater conditions, well construction, and/or
maintenance". Need a single definitive discussion about potential CCR impacts to supply wells in one
section of the report.
62. Need presentation and discussion of the bi-weekly data collected during ash excavation at Units 1-4
inactive basin. Discussion needs to focus on any changes in water levels and geochemical conditions
during and after ash excavation.
22

63. Section 11.1 (Plume Physical Characterization) states on page 11-1 that "The detection of boron at
concentrations in groundwater greater than applicable 2L standards and PBTVs best represents the
leading edge of the CCR-derived plume moving downgradient from the source areas". This statement
needs to be revised to acknowledge that boron concentrations above 2L (700 ug/L) have nothing to do
with the plume's "leading edge".
64. Section 11.1 is mostly a data summary with little or no analysis, context, or significance provided.
Discussion is needed, by source area, to explain why concentrations occur in one area and not in
another based. This should be based on an understanding of local flow directions (analyses need to
focus on boron data along a singular flow path), flow unit thicknesses and properties that may be
affecting boron transport, source variability (ash and pore water) that may be impacting contaminant
concentrations in various downgradient locations differently, and locations of recharge (percolating
infiltration or lateral inflow of groundwater), whether clean, contaminated, or mixed, that may be
impacting contaminant concentrations in various downgradient locations differently. Well IDs and data
need to be included in the discussion. Need discussion to focus on understanding contaminant
transport and whether the plume is expanding or moving and, if so, how and where.
65. Section 11.1. If an analysis or interpretation is based on wells that are not on the same flow path
then it should be assumed that the analysis is flawed (e.g. according to potentiometric maps in figs. 6-16
to 6-20, MW-20DR is not on the same flow path as GWA-2113RU; GWA-29D is not on the same flow path
as IB-3D; U5-2BR is not on the same flow path as MW-38BR; etc). The interpretations need to be revised
accordingly.
66. Pages 11-3, 11-4, 11-5, 11-7, and 11-8 state that certain cross -sections (A -A', K-K', H-H', and L-L')
are transects along the plume centerline. Need discussion explaining what data (well IDs and data) were
used as a basis for the statements that these transects are along the plume centerline. Analyses based
on these transects only make sense if these statements are true and, as pointed out above, it appears
that some wells in the cross -sections are not in fact along the plume centerline.
67. Page 11-3 states that "While PBTVs could not be distinguished on these graphs because values
differ by flow unit, ..." This issue occurs with other similar plots. These plots need to be revised and
scaled (y-axis) to be readable and understandable (perhaps the plots could be stacked by flow unit).
68. Page 11-4 states that "Groundwater elevations are not available for the calculation of vertical
gradients in the well clusters installed near and along the base of the upstream dam..." Need discussion
about the implications for these missing elevations and whether these should be measured.
69. Page 11-4 states that "Upward hydraulic vertical gradients are observed upgradient, ...." Need
discussion about why upward vertical gradients are observed upgradient of the basin and why these
specific locations run counter to the conceptual model regarding vertical gradients across the facility.
Discussion needs to include well IDs, WL data, and local geology.
70. Page 11-4 states that "The horizontal and vertical extent of the boron plume has been defined at
the active ash basin. Further, it can be concluded that monitoring wells across the Site are appropriately
placed and screened to the correct elevations to monitor groundwater quality." Need discussion
describing the basis for this statement, particularly given the fact that some wells are not on flow path, a
23

well had to be substituted on a flow path because of a missing location, 2L/IMAC/BTV exceedances
occur on the compliance boundary in some locations, etc.
71. Page 11-4 provides information about Units 1-4 Inactive Ash Basin. Need discussion about the fact
that a compliance boundary does not exist and implications for 2L compliance.
72. Page 11-5 states that "Boron is reported at concentrations greater than the PBTV but less than the
2L standard at GWA-14D, located upgradient and adjacent to the basin....". Need discussion explaining
the source of the boron at GWA-14D and implications for understanding contaminant transport and
corrective action design.
73. Section 11.3 (Pending Investigations) presents several wells whose analytical results were not
available in time for interpretation in this report. All data collected at these wells needs to be presented
and interpreted.
74. Some of the concentration versus distance plots in figs. 11-46 to 11-60 are flawed along with the
corresponding interpretations. For example, page 11-5 states that "Concentrations of each COI [versus
distance] were measured from sampling conducted September 2015 to August 2017". Because the
plotted concentrations were from wells sampled two years apart, it is not possible to know whether the
trends are due to distance or time. The plots also assume that the wells are along a plume centerline
when this is not the case for every plot (e.g. MW-2DA is not on the same flow path as AS-613RA
according to the potentiometric map of fig. 6-20; similarly, GWA-29 is not on the same flow path as the
other plotted wells). Also, AS-613RA is not in the source area so the plot makes no sense; using flawed
logic, page 11-9 states that boron (and others) show an increasing trend, from source to downgradient,
in the bedrock flow unit, but the statement is based on a source well that is not actually in the source
(AS-6BRA). Plot results, if accurate, show be accompanied by a discussion about the implications of
trends with distance and how this relates to contaminant transport from source to receptor. Discussion
needs to also explain why AS-1 wells were omitted from the plots as it is in the heart of the waste area
and could be used to assess spatial variability of conditions within the waste boundary.
75. Page 11-6 states that "The vertical extent of the plume does not extend into the transition zone or
bedrock beneath or surrounding the Units 1-4 inactive ash basin at concentrations greater than the 2L
standard. This statement is incorrect and needs to be revised accordingly (see GWA-11BRU, GWA-10D,
IB-3D, J.
76. Page 11-6 also states that "Groundwater elevations are not available for the calculation of vertical
gradients in the deep to bedrock clusters installed near the basin". Need discussion of the implications
of this missing data, whether there is a plan to measure the wells, and if not, why not. The report goes
on to state that "...upward gradient exists in upgradient areas, northwest and southwest of the basin".
Need discussion about what wells this refers to and why the vertical gradient in these specific locations
run counter to the conceptual model of vertical gradients across the facility.
77. Page 11-6 provides information about Unit 5 Inactive Ash Basin. Need discussion about the fact
that a compliance boundary does not exist and implications for 2L compliance.
78. Page 11-6 states where boron is above 2L and where it is below 2L but above PBTVs, however, it
provides no discussion of actual concentrations, co-occurring contaminants, groundwater flow
directions, pore water and its spatial variability, or any other context related to its movement from the
24

source area. The discussion needs to provide understanding at a local scale of the factors that control
the movement of the plume or boron within the plume.
79. Page 11-7 states, regarding Unit 5 basin, that "no shallow well location exists in the downgradient
area". Discussion is needed describing the implications for this and for assessing 2L compliance and
contaminant transport.
80. Page 11-7 states that "The vertical extent of the plume does not extend into bedrock beneath or
surrounding the Units 5 inactive ash basin at concentrations greater than the 2L standard. This
statement is incorrect and needs to be revised accordingly (see MW-38, U5-2BR, U5-4BR, U5-05BR, CCR-
U5-05D, GWA-02BR, ...).
81. Page 11-7 also states that an upward gradient exists at MW-37 and MW-38, "probably due to the
Broad River elevation". Discussion is needed to explain in technical terms what this statement means
and implications for contaminant transport and risk to receptors.
82. Page 11-8 provides information about the Ash Storage Area. Need discussion about the revised
location of the compliance boundary (just south of AS-7) and implications for 2L compliance.
83. Need discussion about boron exceedances in CCR-6S located just upgradient of the western ash
storage area and downgradient of the active basin, and implications for understanding contaminant
transport.
84. Need discussion about spatial data gap east of AS-8.
85. Page 11-9 states that "boron is not present in the bedrock flow layer beneath or downgradient of
the ash storage area". This is incorrect (see AS-213R).
86. Page 11-9 also states that "In the deep to bedrock flow layers, the largest downward gradient of
the Site exists at AS-5. Discussion is needed about why this is mentioned or deemed to be important,
particularly given the fact that AS-5 is not inside or downgradient of the source area.
87. Page 11-9 states that "Transects planned for use in the geochemical model are slightly different
than those shown in cross-section on the figures." Discussion is needed about why this is the case, why
the cross section on the figures used the wells that it used, and implications for understanding
contaminant transport.
88. Page 11-10 discusses the wells used for geochemical modeling flow path transects. U5-4 is not
along the same flow path as U5-7 according to potentiometric maps in figs. 6-16, 6-18, and 6-20. The
same is true of CCR-12 and AB-2. Need discussion about this apparent discrepancy and implications for
modeling and understanding contaminant transport.
89. Page 11-10 states generically that "There are 10 wells located perpendicular to the proposed
centerlines of flow for the Unit 5 inactive ash basin". Need well IDs and a map showing the wells, local
groundwater flow directions, and potentiometric contours.
90. Page 11-10 states that "One notable exception [to concentrations decreasing away from the source
area] is seen at CCR-U5-4D which has the highest concentration of boron for this source area". Need
discussion about why this is the case and implications for understanding contaminant transport.
25

91. Page 11-10 states that "Of the 11 wells along the two centerlines of flow for this source area, two
wells have zero valid sampling events (GWA-2BR and U5-2S-SLA)...." Similarly, U5-5BR and U5-4BRA
have had zero valid sampling events, and AB-3SLA, AB-313RUA, AB-3BR, and AS-713RA have had zero valid
sampling events. Need discussion explaining the implications of this and how and when these data gaps
will be filled.
92. Page 11-11 states that "The active ash basin — west transect begins at two side gradient wells with
elevated concentrations of several COls." Need discussion explaining why the transect begins in side
gradient wells as opposed to heart -of -source wells, why COls are elevated in the side gradient wells, and
whether COls are higher in heart -of -source locations and implications for understanding contaminant
transport.
93. Page 11-11 states that "Maximum concentrations of boron along this flow path are located at CCR-
12S for the shallow flow layer, GWA-27DA for the deep flow layer, and GWA-27BR for the bedrock
layer". This is a summary of data observations but does not explain why this is the case or implications
for contaminant transport. Need discussion to address this.
94. Page 11-11 states that ".... the total vertical length of ash in borings along the transect are as
follows:...." Need discussion explaining the significance of these thicknesses, spatial variations,
adequacy of boring density, and how the findings relate to pore water results and downgradient
concentrations. One generic sentence was used to address this which stated "this heterogeneous
nature of the ash storage area can account for the minor fluctuations in concentrations along the flow
path." Need specificity, well IDs and data, etc.
95. Page 11-12, regarding the ash storage area transect, states generically that "There are 12 wells
perpendicular to the centerline of flow for the ash storage area transect". Need well IDs and a map
showing the wells, local groundwater flow directions, and potentiometric contours.
96. Page 11-12, regarding the active ash basin — east transect, states generically that "There are 12
wells perpendicular to the centerline of flow for the ash storage area transect". Need well IDs and a
map showing the wells, local groundwater flow directions, and potentiometric contours.
97. Section 11.2 (Plume Chemical Characterization) summarizes COls across the facility and provides
facility -wide ranges and numbers of detections. Need discussion of specific details by source area
including well IDs and transport characteristics from source to receptor. The section also discusses
primary attenuation mechanisms in a generic textbook sense but did not provide relevant and specific
details by source area to explain the transport or lack of transport in "hot" areas of the sites. Need
discussion addressing this.
98. Page 11-15 states generically that "Goldberg (1997) lists aluminum andiron oxides, magnesium
hydroxide, clay minerals, calcium carbonate (limestone), and organic matter as important sorption
surfaces in soils (Goldberg, 1997)". Similarly, on page 11-17 the report generically states that
"Chromium mobility depends on sorption characteristics of the soil, including clay content, iron, and
manganese oxide content and the amount of organic matter present." Rather than generics, need
discussion, by source area and using specific well IDs and data, about the extent to which this is affecting
contaminant transport in "hot" areas of the sites.
26

99. Page 11-18 states that "Despite the low apparent mobilization percentage, iron is often one of the
COls detected in the highest concentrations in ash pore water. The extent to which iron dissolves in
water depends on the amount of oxygen present in the water, and to a lesser extent, upon its degree of
acidity (Stumm & Morgan, 1996). Need discussion, by source area and using specific well IDs and data,
about the extent to which local geochemical conditions are causing iron dissolution and thus affecting
dissolved iron distribution in "hot" areas of the sites.
100. Page 12-1. Need to compare the data collected since the report was submitted to the risk
assessment criteria to ensure that the risk assessment is up to date.
101. Page 12-1 states that "AOW locations are outside the scope of this risk assessment because
AOWs, wastewater, and wastewater conveyances (discharge canals) are evaluated and governed wholly
separate in accordance with the NPDES Program administered by NCDEQ DWR. Page 12-3 states that
"Samples collected at the locations SW-BRAB-2 and SW-BRAB-3 were not considered in this risk
assessment update because of their proximity to an NPDES outfall on the Broad River". Page 12-6 states
that samples in Exposure Areas 3 and 4 were limited to AOW samples and AOW samples were not
evaluated for risk because they are included under the NPDES program. However, all AOW locations
need to be included in the risk assessment, not for 2B compliance, but to allow the Division Director to
properly evaluate all factors pursuant to 02L .0106 (i), which includes "risk" for purposes of CAP
approval.
102. The risk assessment needs to be re-evaluated once sediments in the Broad River are collected (see
page 11-31).
103. Page 12-3 states that "Samples with turbidity greater than 2B of 25 NTUs were also omitted from
this [risk assessment] evaluation". The risk assessment needs to be re-evaluated using turbid samples.
104. Page 12-3 stated that "On -site surface water sample locations included in this assessment were
SW-3 and SW-4 from Suck Creek and 47 additional surface water samples collected in 2016-2017 from
the Broad River and Suck Creek". The risk assessment needs to include the NCDENR surface water
locations collected in March 2014.
105. A table is needed that summarizes the risks (specific bird or mammal) associated with each source
area and why the risk was identified (specific contaminant and sample location).
106. Page 12-7 states that "This update to the human health and ecological risk assessment supports a
risk classification of "low" for groundwater related consideration". Discussion is needed providing the
technical and administrative basis for this conclusion and why the "low risk" is suggested for the facility
as a whole rather than individual source areas each of which will require a closure plan.
107. Page 13-1 states that "Once the flow, transport, and geochemical models for the Site accurately
reproduce observed Site conditions, they can be used as predictive tools...." For each source area, the
models should be able to simulate with reasonable certainty contaminant concentrations at shallow,
deep, and bedrock wells with exceedances of 2L/IMAC/BTVs. That is, target wells need to be in "hot"
areas of each source area. ARO requests that preliminary results of simulated versus observed
concentrations at target wells, along with quantitative sensitivity analyses, be provided at least 60 days
prior to CAP submittal. This will allow time for the Division to approve the selected target wells and the
27

models' ability to simulate observed concentrations prior to their use as predictive tools during CAP and
closure designs.
108. Page 13-5. The geochemical model report needs to show the distribution of Eh and pH across
each flow unit and source area.
109. Page 14-3 states that "The horizontal gradients, horizontal hydraulic conductivity, and seepage
velocities indicate that most of the groundwater flow occurs through the transition zone and bedrock, as
most of the regolith encountered downgradient of the basin is thin and less likely to be saturated".
Need discussion about saprolite thickness and bedrock fracturing in individual source areas. Discussion
should include specific well IDs and mapping and needs to focus on "hot" areas of concern. To justify
the statement, the discussion needs to include the relative volumes of flow expected to occur in
fractures in a given area versus the volume of flow expected to occur through the porous saprolite in
that area. The need is to understand the nature of contaminant transport in specific areas rather than
"generally" across the facility. This is particularly important given the significant geologic variability
from area to area.
110. Page 14-20 provides cursory trend analysis and references figures that show contaminant
concentration trends across the facility. Need discussion, by source area and using specific well IDs and
data, explaining the implications of the observed spatial and temporal trends, whether they represent
plume movement and (or) expansion, and if so how that affects understandings of plume extent, 2L
compliance, and corrective action design.
111. Section 15.0 (Conclusions and Recommendations) contains a number of conclusions that appear
to be in error or partial error. The preceding comments address these.
112. Section 15.5.1 (CAP Preparation Process) describes what the CAP will include but does not
mention that additional analysis in individual source areas is needed. It needs to be acknowledged that
the factors affecting contaminant transport are needed in support of CAP and closure design.
113. The Executive Summary contains statements that appear to be in error or partial error. The above
comments address these.
114. The report failed to include several elements specifically requested in the CSA Content document
of July 18, 2017 provided to Duke prior to the 7/21/17 CSA Guideline meeting. The above comments
address these.
28

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
November 13, 2018
Subject: Final Classification of the Three Coal Combustion Residuals Surface
Impoundments located at Duke Energy's James E. Rogers Energy Complex
(formerly Cliffside Steam Station), Rutherford and Cleveland County, NC,
Pursuant to N.C. Gen. Stat. § 130A-309.213(d)(1).
Dear Mr. Draovitch:
Pursuant to the Coal Ash Management Act (HB 630, Session Law 2016-95), the North Carolina
Department of Environmental Quality (NCDEQ) has determined that Duke Energy has met the
low -risk classification criteria set forth in N.C. Gen. Stat. § 130A-309.213(d)(1) for the three
coal combustion residuals surface impoundments, called the Active Ash Basin, Units 1-4
Inactive Ash Basin, and Unit 5 Inactive Ash Basin, located at Duke Energy's James E. Rogers
Energy Complex (formerly Cliffside Steam Station) in Rutherford and Cleveland County, NC.
NCDEQ makes the following specific findings:
1. Duke Energy has established permanent water supplies as required for the above
referenced impoundments pursuant to N.C. Gen. Stat § 130A-309.211(c1). See Exhibit 1
(Duke Energy Alternate Water Supply Submittal), Exhibit 2 (Alternate Water Supply
Supplemental Documents), and Exhibit 3 (NCDEQ Alternate Water Supply Approval);
and
2. Duke Energy has rectified any deficiencies identified by, and otherwise complied with
the requirements of, any dam safety order issued by the Environmental Management
Commission for the above referenced impoundments pursuant to N.C. Gen. Stat. § 143-
215.32. Specifically, NCDEQ has verified through inspection that Duke Energy has
rectified all deficiencies identified by Dam Safety Order 16-01 (issued on August 22,
2016) at Duke Energy's James E. Rogers Energy Complex. See Exhibit 4 (Dam Safety
Order 16-01), Exhibit 5 (Dam Inspection Reports), Exhibit 6 (October 3, 2018 DEMLR
e:! � � Q E Q
.� � of fFanms�Gr I pYtl�'�
North Carolina Department of Environmental Quality
217 West Jones Street 11601 Mail Service Center I Raleigh, North Carolina 27699-1601
919.707.8600

Letter Regarding Dam Safety Order 16-01 Compliance Status), and Exhibit 7 (October
10, 2018 EMC Meeting Minutes).
Based upon the determinations above and in accordance with the Coal Ash Management Act,
NCDEQ classifies the three coal combustion residuals surface impoundments, called the Active
Ash Basin, Units 1-4 Inactive Ash Basin, and Unit 5 Inactive Ash Basin, at Duke Energy's
James E. Rogers Energy Complex as low -risk.
If you have any questions about NCDEQ's determinations provided in this letter, please contact
me at [phone].
Sincerely,
a,-q. C. %9,,
Sheila Holman
Assistant Secretary for Environment
cc: Linda Culpepper, NCDEQ, Director, Division of Water Resources (no attachments)
Michael Scott, NCDEQ, Director, Division of Waste Management (no attachments)
Toby Vinson, NCDEQ, Director, Division of Energy Mineral and Land Resources (no
attachments)
Bill Lane, NCDEQ, General Counsel (no attachments)
NCDEQ Central File
DIEQ
9�M6n4rw�gY yyl4
North Carolina Department of Environmental Quality
217 West Jones Street 11601 Mail Service Center J Raleigh, North Carolina 27699-1601
919.707.8600

u 1�
STArF F
0,
LJAM VIDF��
DEQ Coal Combustion Residuals
Surface Impoundment
Closure Determination
Rogers Energy Complex/Cliffside Steam Station
April 1, 2019

DEQ Coal Combustion Residuals Surface Impoundment Closure Determination
Rogers Energy Complex/Cliffside Steam Station
Executive Summa
The Coal Ash Management Act (CAMA) establishes criteria for the closure of coal
combustion residuals (CCR) surface impoundments. The CCR surface impoundments located at
Duke Energy Carolinas, LLC's (Duke Energy) Rogers Energy Complex/formerly Cliffside Steam
Station (Rogers Energy/Cliffside) in Stokes County, NC have received a low -risk classification.
Therefore, according to N.C. Gen. Stat. § 130A-309.214(a)(3), the closure option for CCR surface
impoundments is at the election of the North Carolina Department of Environmental Quality
(DEQ or Department). CAMA provides three principal closure pathways: (a) closure in a manner
allowed for a high -risk site, such as excavation and disposal in a lined landfill [CAMA Option A];
(b) closure with a cap -in -place system similar to the requirements for a municipal solid waste
landfill [CAMA Option B]; or (c) closure in accordance with the federal CCR rule adopted by EPA
[CAMA Option C].
In preparing to make its election, DEQ requested information from Duke Energy related
to closure options. By November 15, 2018, Duke Energy provided the following options for
consideration: closure in place, full excavation, and a hybrid option that included some
excavation with an engineered cap on a smaller footprint of the existing CCR surface
impoundments. DEQ held a public information session on January 22, 2019 in Forest City, NC
where the community near Rogers Energy/Cliffside had the opportunity to learn about options
for closing CCR surface impoundments and to express their views about proposed criteria to
guide DEQ's coal ash closure decision making process. To evaluate the closure options, the
Department considered environmental data gathered as part of the site investigation, permit
requirements, ambient monitoring, groundwater modeling provided by Duke Energy and other
data relevant to the CAMA requirements.
DEQ elects the provisions of CAMA Option A that require movement of coal ash to an
existing or new CCR, industrial or municipal solid waste landfill located on -site or off -site for
closure of the CCR surface impoundments at the Rogers Energy/Cliffside facility in accord with
N.C. Gen. Stat. § 130A-309-214(a)(3). In addition, DEQ is open to considering beneficiation
projects where coal ash is used as an ingredient in an industrial process to make a product as
an approvable closure option under CAMA Option A.
DEQ elects CAMA Option A because removing the coal ash from unlined CCR surface
impoundments at Rogers Energy/Cliffside is more protective than leaving the material in place.
DEQ determines that CAMA Option A is the most appropriate closure method because removing
the primary source of groundwater contamination will reduce uncertainty and allow for flexibility
in the deployment of future remedial measures.
Duke Energy will be required to submit a final Closure Plan for the CCR surface
impoundments at Rogers Energy/Cliffside by August 1, 2019. The Closure Plan must conform to
this election by DEQ.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 1

Intrnrli irtinn
DEQ has evaluated the closure options submitted by Duke Energy for the two CCR surface
impoundments at Rogers Energy/Cliffside. This document describes the CAMA requirements for
closure of CCR surface impoundments, the DEQ evaluation process to make an election under
CAMA for the subject CCR surface impoundments at the Rogers Energy/Cliffside site, and the
election by DEQ for the final closure option.
II. Site History
Duke Energy owns and operates the Rogers Energy/Cliffside station, which consists of
approximately 1,000 acres in Mooresboro, Rutherford and Cleveland Counties, North
Carolina. Rogers Energy/Cliffside began operation in 1940 and has a current capacity of 1,381
megawatts.
CCR coal ash residuals and other liquid discharges from coal combustion processes at the
site have historically been managed in ash basins, which consist of the Active Ash basin, the Units
1-4 Inactive Ash Basin, and the Unit 5 Inactive Ash Basin. The Units 1-4 Inactive Ash Basin is
located immediately east of the retired Units 1-4. It was constructed in 1957 and began
operations the same year. The Units 1-4 Ash Basin was retired in 1977 once it reached
capacity. However, stormwater ponds were constructed on top of the retired basin and
continued to operate until the basin was excavated.
The Unit 5 Inactive Ash Basin is located on the western portion of the site, west and
southwest of Units 5 and 6. The Unit 5 Inactive Ash Basin is currently used as a laydown yard for
the station. This ash basin was constructed in 1970 (in advance of Unit 5 operations) and received
sluiced ash from Unit 5 starting in 1972 until it was retired in 1980 when it reached full capacity. It
is currently covered with a layer of topsoil and is stable with vegetation. The Active Ash Basin is
located on the eastern portion of the site, east and southeast of Units 5 and 6. Construction of
the Active Ash Basin occurred in 1975, and it began receiving sluiced ash from Unit 5. The Active
Ash Basin expanded in 1980 to its current footprint and continues to receive sluiced bottom ash
from Unit 5 in addition to other waste streams.
There are two CCR surface impoundments at the site: the Active Ash Basin and Unit 5
Inactive Ash Basin. The Units 1-4 Inactive Ash Basin was excavated and is no longer considered a
CCR surface impoundment. The Active Ash Basin and the Unit 5 Inactive Ash Basin are
approximately 132 acres in size and contain approximately 7,390,000 tons of CCR. The Active
Ash Basin and Unit 5 Inactive Ash Basin are subject to the requirements of General Statute §
130A-309.214(a)(3).
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 2

III. CAMA Closure Reauirements
CAMA establishes closure requirements for CCR surface impoundments. The General
Assembly has mandated that DEQ "shall review a proposed Coal Combustion Residuals Surface
Impoundment Closure Plan for consistency with the minimum requirements set forth in
subsection (a) of this section and whether the proposed Closure Plan is protective of public
health, safety, and welfare; the environment; and natural resources and otherwise complies with
the requirements of this Part." N.C. Gen. Stat. § 130A-309.214(b). Similarly, the General
Assembly has required that DEQ "shall disapprove a proposed Coal Combustion Residuals Surface
Impoundment Closure Plan unless the Department finds that the Closure Plan is protective of
public health, safety, and welfare; the environment; and natural resources and other complies
with the requirements of this Part." N.C. Gen. Stat. § 130A-309.214(c).
CAMA requires DEQ to review any proposed Closure Plan for consistency with the
requirements of N.C. Gen. Stat. § 130A-309.214(a). See N.C. Gen. Stat. § 130A-309.214(b). DEQ
must disapprove any proposed Closure Plan that DEQ finds does not meet these requirements.
See N.C. Gen. Stat. § 130A-309.214(c). Therefore, an approvable Closure Plan must, at a
minimum, meet the requirements of N.C. Gen. Stat. § 130A-309.214(a).
Pursuant to N.C. Gen. Stat. § 130A-309.213(d)(1), DEQ has classified the CCR surface
impoundment at Rogers Energy/Cliffside station as low -risk. The relevant closure requirements
for low -risk impoundments are in N.C. Gen. Stat. § 130A-309.214(a)(3), which states the
following:
• Low -risk impoundments shall be closed as soon as practicable, but no later
than December 31, 2029;
• A proposed closure plan for a low -risk impoundment must be submitted as
soon as practicable, but no later than December 31, 2019; and
• At a minimum, impoundments located in whole above the seasonal high
groundwater table shall be dewatered and impoundments located in whole
or in part beneath the seasonal high groundwater table shall be dewatered
to the maximum extent practicable.
In addition, N.C. Gen. Stat. § 130A-309.214(a)(3) requires compliance with specific closure
criteria set forth verbatim below in Table 1. The statute provides three principal closure
pathways: (a) closure in a manner allowed for a high -risk site, such as excavation and disposal in
a lined landfill [CAMA Option A]; (b) closure with a cap -in -place system similar to the
requirements for a municipal solid waste landfill [CAMA Option 6]; or (c) closure in accordance
with the federal CCR rule adopted by EPA [CAMA Option C]. For each low -risk impoundment, the
choice of the closure pathway in CAMA is at the "election of the Department."
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 3

Table 1: CAMA Closure Options for Low -Risk CCR Surface Impoundments
N.C. Gen. Stat. § 130A-309.214(a)(3)
At the election of the Department, the owner of an impoundment shall either:
a. Close in any manner allowed pursuant to subdivision (1) of this subsection; [CAMA Option A]
b. Comply with the closure and post -closure requirements established by Section .1627 of Subchapter B
of Chapter 13 of Title 15A of the North Carolina Administrative Code, except that such impoundments
shall not be required to install and maintain a leachate collection system. Specifically, the owner of an
impoundment shall Comply with the closure and post -closure requirements established by Section
.1627 of Subchapter B of Chapter 13 of Title 15A of the North Carolina Administrative Code, except
that such impoundments shall not be required to install and maintain a leachate collection system.
Specifically, the owner of an impoundment shall install and maintain a cap system that is designed to
minimize infiltration and erosion in conformance with the requirements of Section .1624 of
Subchapter B of Chapter 13 of Title 15A of the North Carolina Administrative Code, and, at a minimum,
shall be designed and constructed to (i) have a permeability no greater than 1 x 10-5 centimeters per
second; (ii) minimize infiltration by the use of a low -permeability barrier that contains a minimum 18
inches of earthen material; and (iii) minimize erosion of the cap system and protect the low -
permeability barrier from root penetration by use of an erosion layer that contains a minimum of six
inches of earthen material that is capable of sustaining native plant growth. In addition, the owner of
an impoundment shall (i) install and maintain a groundwater monitoring system; (ii) establish financial
assurance that will ensure that sufficient funds are available for closure pursuant to this subdivision,
post -closure maintenance and monitoring, any corrective action that the Department may require,
and satisfy any potential liability for sudden and nonsudden accidental occurrences arising from the
impoundment and subsequent costs incurred by the Department in response to an incident, even if
the owner becomes insolvent or ceases to reside, be incorporated, do business, or maintain assets in
the State; and (iii) conduct post -closure care for a period of 30 years, which period may be increased
by the Department upon a determination that a longer period is necessary to protect public health,
safety, welfare; the environment; and natural resources, or decreased upon a determination that a
shorter period is sufficient to protect public health, safety, welfare; the environment; and natural
resources. The Department may require implementation of any other measure it deems necessary to
protect public health, safety, and welfare; the environment; and natural resources, including
imposition of institutional controls that are sufficient to protect public health, safety, and welfare; the
environment; and natural resources. The Department may not approve closure for an impoundment
pursuant to sub -subdivision b. of subdivision (3) of this subsection unless the Department finds that
the proposed closure plan includes design measures to prevent, upon the plan's full implementation,
post -closure exceedances of groundwater quality standards beyond the compliance boundary that
are attributable to constituents associated with the presence of the impoundment; [CAMA Option B]
or
c. Comply with the closure requirements established by the United States Environmental Protection
Agency as provided in 40 CFR Parts 257 and 261, "Hazardous and Solid Waste Management System;
Disposal of Coal Combustion Residuals From Electric Utilities." [CAMA Option C]
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 4

By referencing the closure options for high -risk CCR surface impoundments in
"subdivision (1)" or N.C. Gen. Stat. § 130A-309.214(a)(1), CAMA allows for closure of a low -risk
CCR impoundment in N.C. Gen. Stat. § 130A-309.214(a)(3) through the same removal scenarios:
• "Convert the coal combustion residuals impoundment to an industrial landfill by
removing all coal combustion residuals and contaminated soil from the impoundment
temporarily, safely storing the residuals on -site, and complying with the requirements
for such landfills." N.C. Gen. Stat. § 130A-309.214(a)(1)a.; or
• "Remove all coal combustion residuals from the impoundment, return the former
impoundment to a nonerosive and stable condition and (i) transfer the coal
combustion residuals for disposal in a coal combustion residuals landfill, industrial
landfill, or municipal solid waste landfill or (ii) use the coal combustion products in a
structural fill or other beneficial use as allowed by law." N.C. Gen. Stat. § 130A-
309.214(a)(1)b.
IV. DEQ Election Process
Beginning with a letter to Duke Energy on October 8, 2018, DEQ began planning for a
thorough evaluation of the closure options for low -risk CCR surface impoundments before
making an election as outlined in Table 1 above. DEQ's objectives were to receive input on
closure options from Duke Energy and to engage with community members near low -risk sites.
DEQ outlined the following schedule in the October 8, 2018 letter:
• November 15, 2018 — Duke Energy submittal of revised closure option analyses and
related information
• January 22, 2019 — DEQ public meeting near Rogers Energy/Cliffside
• April 1, 2019 — DEQ evaluation of closure options
• August 1, 2019 — Duke Energy submittal of closure plan
• December 1, 2019 — Duke Energy submittal of updated corrective action plan for all
sources at the Rogers Energy/Cliffside site that are either CCR surface impoundments
or hydrologically connected to CCR surface impoundments
DEQ received the requested information from Duke Energy by November 15, 2018:
closure options analysis, groundwater modeling and net environmental benefits assessment.
These materials are posted on the DEQ website. Duke Energy provided the following options for
consideration: closure in place, full excavation with an onsite landfill, and a hybrid option that
included some excavation with an engineered cap on a smaller footprint of the existing
impoundment for the Active Ash Basin. Duke Energy proposed closure in place and full
excavation with an onsite landfill for the Unit 5 Inactive Ash Basin.
In preparing to make its election of the closure option, DEQ considered environmental
data contained in the comprehensive site assessment, permit requirements, ambient monitoring,
closure options analysis and groundwater modeling provided by Duke Energy and other data
relevant to the CAMA requirements. The Rogers Energy/Cliffside site has extensive amounts of
data that have been collected during the site assessment process, and these data were used as
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 5

part of the evaluation of closure options. DEQ's evaluation of the closure in place and hybrid
option based on groundwater monitoring and modeling data is provided in Attachment A. That
analysis demonstrates that the contaminated plume is already beyond the compliance boundary
for the site. All of these references are part of the record supporting DEQ's determination.
DEQ conducted a public meeting in Forest City, NC near Rogers Energy/Cliffside on
January 22, 2019. There were 28 people who attended the meeting. Approximately 1207
comments were received during the comment period, which closed on February 15, 2019. The
majority of the comments supported closure by removal to a lined landfill. A review and response
to comments are included in Attachment B.
V. DEQ Evaluation of Closure Options
DEQ has evaluated the closure options proposed by Duke Energy for the CCR surface
impoundments at the Rogers Energy/Cliffside facility. The purpose of this evaluation was to
determine which closure option or options may be incorporated into an approvable Closure Plan
under CAMA.
DEQ elects the provisions of CAMA Option A that require movement of coal ash to an
existing or new CCR, industrial or municipal solid waste landfill located on -site or off -site for
closure of the Active Ash Basin and Unit 5 Inactive Ash Basin at Rogers Energy/Cliffside in accord
with N.C. Gen. Stat. § 130A-309.214(a)(3). In addition, DEQ is open to considering beneficiation
projects where coal ash is used as an ingredient in an industrial process to make a product as an
approvable closure option under CAMA Option A.
DEQ elects CAMA Option A because removing the coal ash from the two unlined
impoundments at Rogers Energy/Cliffside is more protective than leaving the material in place.
DEQ determines that CAMA Option A is the most appropriate closure method because removing
the primary source of groundwater contamination will reduce uncertainty and allow for flexibility
in the deployment of future remedial measures.
DEQ does not elect CAMA Option B for the CCR surface impoundments at Rogers
Energy/Cliffside. In N.C. Gen. Stat. § 130A-309.214(a)(3)b, the General Assembly mandated that
"[t]he Department may not approve closure for an impoundment pursuant to [this] sub -
subdivision ... unless the Department finds that the proposed closure plan includes design
measures to prevent, upon the plan's full implementation, post -closure exceedances of
groundwater quality standards beyond the compliance boundary that are attributable to
constituents associated with the presence of the impoundment." N.C. Gen. Stat. § 130A-
309.214(a)(3)b. In light of these requirements and based on DEQ's review of the information
provided by Duke Energy as well as DEQ's independent analysis, DEQ does not believe that Duke
Energy can incorporate CAMA Option B into an approvable Closure Plan for Rogers
Energy/Cliffside.
As DEQ considered the closure options presented by Duke Energy, DEQ evaluated
whether the closure in place or the hybrid options met the requirement for CAMA Option B.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 6

Specifically, DEQ attempted to determine whether upon full implementation of the closure plan
the design would prevent any post -closure exceedances of groundwater standards beyond the
compliance boundary. To address this question, DEQ considered the current state of the
groundwater contamination and reviewed the results of the groundwater modeling submitted
by Duke Energy. The evaluation is provided in Attachment A. DEQ's overall conclusion is that
based on the current geographic scope and vertical extent of the groundwater contamination
plume, and the modeled extent of the plume in the future, DEQ does not believe these two
closure options can meet the requirements of CAMA Option B for the CCR surface impoundments
at Rogers Energy/Cliffside.
DEQ does not elect CAMA Option C (i.e., closure under the federal CCR Rules found in 40
CFR Part 257) for the CCR surface impoundments at Rogers Energy/Cliffside. DEQ has determined
that:
a. Under the facts and circumstances here, CAMA Option C is less stringent than CAMA
Option A. Specifically, DEQ's election of Option A would also require Duke Energy to
meet the requirements of the federal CCR Rule (i.e., CAMA Option C) but election of
CAMA Option C would not require implementation of CAMA Option A.
b. Because CAMA Option A adds additional requirements or performance criteria
beyond Option C, it advances DEQ's duty to protect the environment (see N.C. Gen.
Stat. §§ 279B-2 & 143-211) and the General Assembly's mandate under CAMA that
DEQ ensure that any Closure Plan, which must incorporate an approvable closure
option, is protective of public health, safety, and welfare, the environment, and
natural resources (see N.C. Gen. Stat. § 130A-309.214(b) & (c)).
c. For the CCR surface impoundments for which the closure option(s) must be
determined, CAMA Option A provides a better CAMA mechanism for ensuring State
regulatory oversight of the closure process than Option C, as well as greater
transparency and accountability.
d. While the federal CCR Rule was written to provide national minimum criteria for CCR
surface impoundments across the country, CAMA was written specifically to address
the CCR surface impoundments in North Carolina.
e. While the federal CCR Rule allows CCR surface impoundment owners to select closure
either by removal and decontamination (clean closure) or with a final cover system
(cap in place), EPA anticipates that most owners will select closure through the less
protective method of cap in place.
f. There is considerable uncertainty regarding the status and proper interpretation of
relevant provisions of the federal CCR Rule. For instance, EPA is reconsidering
portions of the federal CCR Rule. Also, the performance standards in 40 CFR §
257.102(d) for cap in place closure are the subject of conflicting interpretations (and
possible litigation) among industry and state authorities.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 7

VI. Conclusion
The final closure plan is due on August 1, 2019 in accordance with this determination.
Based on DEQ's evaluation of the options submitted by Duke Energy, DEQ elects the provisions
of CAMA Option A that require movement of coal ash to an existing or new CCR, industrial or
municipal solid waste landfill located on -site or off -site for closure of the Active Ash Basin and
Unit 5 Inactive Ash Basin at Rogers Energy/Cliffside in accord with N.C. Gen. Stat. § 130A-
309.214(a)(3). In addition, DEQ is open to considering beneficiation projects where coal ash is
used as an ingredient in an industrial process to make a product as an approvable closure option
under CAMA Option A.
While beneficiation is not a requirement of the closure plan, DEQ encourages Duke
Energy to consider opportunities for beneficiation of coal ash that would convert coal
combustion residuals into a useful and safe product.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 8

ATTACHMENT A
DEQ EVALUATION OF CLOSURE IN PLACE AND HYBRID OPTIONS BASED ON
GROUNDWATER MONITORING AND MODELING DATA
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 9

DEQ EVALUATION OF CLOSURE IN PLACE AND HYBRID OPTIONS BASED ON
GROUNDWATER MONITORING AND MODELING DATA
Groundwater Monitoring Summary
As DEQ considered the closure options presented by Duke Energy, DEQ evaluated
whether the closure in place or the hybrid options met the requirement for CAMA Option B.
Specifically, DEQ attempted to determine whether the design would prevent any post -closure
exceedances of groundwater standards beyond the compliance boundary upon full
implementation of the closure plan. To help address this question, DEQ considered the current
state of the groundwater contamination.
Figure ES-1 shows the inferred general extent of constituent migration in groundwater
based on evaluation of concentrations greater than both the calculated PBTVs, 2L Standards,
and/or IMACs. The figure also shows that groundwater within the area of the CCR surface
impoundments generally flows from south to north and discharges to the Broad River and to Suck
Creek, a perennial stream flowing south to north and discharging to the Broad River. The
horizontal extent of contaminant concentrations greater than the PBTV or 2L Standard
approximates the leading edge of the CCR-derived plume (yellow shaded area) from the source
areas.
The plume near the Active Ash Basin has extended beyond the compliance boundary near
the northeast corner of the CCR surface impoundment where a small portion of an adjacent
property extends along the Broad River. The plume has also extended beyond the compliance
boundary in the area of the ash storage area.
The vertical extent of most constituents of interest is within the shallow and transition
flow zones. However, the results of the assessment show that the bedrock aquifer has been
impacted by CCR. Arsenic, sulfate, thallium, TDS, and total radium appear to have exceedances
in the bedrock north of Unit 5 Inactive Ash Basin and/or near the plant.
DEQ concludes that the contaminated groundwater plume in the area near the Active Ash
Basin has extended beyond the compliance boundary near the northeast corner of the
impoundment where a small portion of an adjacent property extends along the Broad River. The
plume has also extended beyond the compliance boundary in the area of the ash storage area.
The horizontal extent of nearly all COls such as arsenic, chromium, cobalt, iron, manganese,
strontium, sulfate, thallium, TDS, vanadium, total uranium, and total radium occur in the shallow
flow zone and are generally within the boron plume footprint. Total chromium and cobalt appear
to have some exceedances in isolated pockets outside the boron plume near the plant. Strontium
and sulfate plumes appear to be slightly more widespread, extending outside the boron plume
near the Unit S Inactive Ash Basin and the plant.
The Unit 5 Inactive Ash Basin does not have a NPDES or any other agency permit and
therefore does not have compliance boundaries. Any exceedance of the 2L Standards in this
area, including within the waste boundary is subject to cleanup requirements.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 10

Figure EG£ Cliffside from 2017 C A Update
-
!
lw
%
ALT
\
/
\
w
-
® a}
-
•
4v .
• � � � » -_ --� y -- . -
-TU_ ƒ
r\ _
§ L,
`
cn
Lw
� � K $ «§
� \ �
� «�� i
�..<
_ .
§
§
GEC ENE 9coFFS OE CLOSURE DETERQNATON-AP RILt 2019-t

Figure ES-1 Legend: Cliffside from 2017 CSA Update
i i= r:FNn
AREA OF CDNCENTPATION IN GROUNDWATER
ABOVE NC2L BEE NOTE 5)
ASH BASIN 1 A TE BOUNDARY
APPRO IMATE= LANDFILL WASTE BOUNDARY
GENERALIZED GROUNOWATER FLOW DIRECTION
RESIDENTIAL UNIT
0ESIGNATED EFFLUENT CHANNEL WITH FLOW DIRECTION
STREAM WITH FLOW DIRECTION
DUKrz ENERGY PROPERV BOUNDARY
NOTE.
i OCTOBIER, 20 1� AERIAL PHQTC APH'Y OBTAINED FROM WOGLIE EARTH PRO ON
SEPTEMBER 11, 2017. ACRIAL OA7CID APRIL 6. Zp17
2 $TR:AM FROM AVIF.0 NRTR RFPORt.2015.
3 CIENERALVE0 OROI,JNDWAtiTER FLOW DI REQTION FlAaf-_0 ON APR IL 3, 2017 WATER
LEVEL DATA.
A PROPERTY BOUNDARY PROVIDED BY QLNk'F ENERGY.
5 QENR RALtZEO ARF, 1 EXTENT OF MiQ41ATION REPRESENTED BY NCAC L
EXCEEE l N(X e0k0N.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 12

Groundwater Cross-section Modelin
DEQ evaluated cross -sections of the groundwater modeling results provided by Duke
Energy to determine whether Duke Energy's final closure Option 1: Closure -in -Place and Option
3: Hybrid for the Active Ash Basin would meet the criteria of CAMA Option B. DEQ considered
whether the agency could conclude that the proposed closure option includes design measures
to prevent any post closure exceedances of the 2L groundwater quality standards (15A NCAC
02L) at the compliance boundary upon the plan's full implementation. Cross section A -A' was
evaluated and can be seen in the figures below. This cross section represents where the boron
concentration above the 2L standard of 700 µg/L has crossed the compliance boundary based
on groundwater monitoring and modeling.
Next, the model results were evaluated based on the following model simulations:
• current conditions in 2017 when the model was calibrated based on raw field data
• upon completion of the final closure -in -place cover system at t=0 years
• closure -in -place option at t=100 years
• upon completion of the hybrid option at t=0 years
• hybrid option at t=125 years
The table below summarizes the results from the model simulations. The boron
concentrations depicted in the table represent the maximum boron concentration in any layer
(ash, saprolite, transition zone, and bedrock) of the model.
Cliffside Modeling Results for Cross -Section A -A'
Model Simulation
Maximum Concentration
Depth of GW
Width of
of Boron Above 2L
Contamination Above 2L
Contamination Plume
Beyond Compliance
Beyond Compliance
Beyond Compliance
Boundary
Boundary
Boundary
(µg/L)
(feet bgs)
(feet)
Current Conditions
700-4,000
80
600
Completion of Final
700-4,000
80
580
Cover (t=0 yrs)
Final Cover
700-4,000
120
175
(t=100 yrs)
Completion of
700-4,000
80
580
Hybrid (t=0 yrs)
Hybrid (t=125 yrs)
700-4,000
120
100
bgs — below ground surface
These data illustrate that after completion of closure with the final cover or hybrid option,
the groundwater plume still extends beyond the compliance boundary above the 2L groundwater
standard and the area of the plume requiring remediation is immense. Even 100 or 125 years
beyond completion of closure, the area of the plume requiring remediation remains extensive
under these two closure options.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 13

DEQ recognizes that there are no groundwater remediation corrective actions included
in the groundwater modeling simulations submitted to DEQ as part of Duke Energy's closure
options analysis documentation. However, based on the current geographic scope, vertical
extent of the groundwater contamination plume, and future modeled extent of the plume, DEQ
does not believe these two closure options can meet the requirements of CAMA Option B for
the Active Ash Basin. DEQ also does not believe Duke Energy's Option 1: Closure -in -Place for
the Unit 5 Inactive Ash Basin can meet the requirements of CAMA Option B, given the extent of
the groundwater plume beyond the waste boundary, extending to the Broad River as depicted
in ES-1 in Attachment B, and the lack of a compliance boundary for the impoundment.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 14

CLIFFSIDE CURRENT CONDITIONS IN 2018
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000

CLIFFSIDE UPON COMPLETION OF FINAL COVER IN 2022
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
IDE CLOSURE DETERMINATION - APRIL 1, 2019 - 16

CLIFFSIDE FINAL COVER IN 2125, t — 100 years
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 17

CLIFFSIDE UPON COMPLETION OF HYBRID IN 2023
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 18

CLIFFSIDE HYBRID IN 2125, t — 100 years
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 19

CLIFFSIDE CURRENT CONDITIONS IN 2018
CROSS SECTION A -A' (VIEWED FROM EAST SIDE OF CROSS SECTION LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
10
Cliffside model lavers:
Ash 1-8
Saprolite 9-13
TZ 14-16
Bedrock 16-28
Vertical
exaggeration X 3
compliance AJ
boundary
A -A' —800 ft
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 20

CLIFFSIDE UPON COMPLETION OF FINAL COVER IN 2022, t = 0
CROSS SECTION A -A' (VIEWED FROM EAST SIDE OF CROSS SECTION LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
0
Cliffside model lavers:
Ash 1-8
Saprolite 9-13
TZ 14-16
Bedrock 16-28
Vertical
exaggeration X 3
compliance A'
boundary
A -A' —800 ft
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 21

CLIFFSIDE FINAL COVER IN 2125, t — 100 years
CROSS SECTION A -A' (VIEWED FROM EAST SIDE OF CROSS SECTION LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
0
Cliffside model lavers:
Ash 1-8
Saprolite 9-13
TZ 14-16
Bedrock 16-28
Vertical
exaggeration X 3
compliance n J
A -A' —800 ft
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 22

CLIFFSIDE UPON COMPLETION OF HYBRID IN 2023, t = 0
CROSS SECTION A -A' (VIEWED FROM EAST SIDE OF CROSS SECTION LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
w
Cliffside model lavers:
Ash 1-8
Saprolite 9-13
TZ 14-16
Bedrock 16-28
Vertical
exaggeration X 3
compliance A I
A -A' —800 ft
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 23

CLIFFSIDE UPON COMPLETION OF HYBRID IN 2150, t — 125 years
CROSS SECTION A -A' (VIEWED FROM EAST SIDE OF CROSS SECTION LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
U1,
Cliffside model lavers:
Ash 1-8
Saprolite 9-13
TZ 14-16
Bedrock 16-28
Vertical
exaggeration X 3
compliance n J
A -A' —800 ft
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 24

ATTACHMENT B
RESPONSE TO COMMENTS
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 25

RESPONSE TO COMMENTS
I. Summary of Responses to Comments
The North Carolina Department of Environmental Quality ("NCDEQ," or "Department")
received approximately 1207 comments regarding the five closure options at the Duke Energy
Rogers facility. The majority of the comments supported closure by removal to a lined landfill
without specifying the location of the landfill. A sizeable minority specifically recommended
excavating coal ash and moving it to an onsite landfill. A small minority of commenters either
urged for excavation without registering any opinion as to how the excavated coal ash should be
handled, or discussed disposal options other than relocation to a lined landfill. No commenters
unequivocally supported closure -in -place, however, one commenter registered qualified support
for this option. Detailed responses to the comments received by the Department regarding
closure options for this site, as well as responses to those comments, are below.
II. Detailed Responses to Comments
A. Closure -in -place
No comments were received which unequivocally favored closure -in -place. Of the more
than 1200 comments received, all but two advocated for excavating coal ash from its existing
location. A very small number of commenters solely urged for excavation of coal ash without any
further specific comment. Similarly, a small number of commenters registered their opposition
of cap -in -place, went on to cite specific reasons for their opposition of cap -in -place, but made no
specific proposal regarding disposition of excavated coal ash.
Among these commenters, the reasons cited for opposing cap -in -place were: water
quality and health concerns, concerns regarding Duke's motives in proposing this solution,
concerns over the effectiveness of long-term monitoring, accountability concerns, and/or general
fairness concerns over leaving coal ash in place in some places when it is being excavated at
others. One commenter did not specifically address any of the closure options, but, rather
expressed his concern with the effects of contamination associated with coal ash. These general
concerns are summarized and addressed in this section under the sub -heading "General
Opposition of Closure -in -place." Most commenters expressed some opinion regarding the
ultimate disposition of excavated coal ash and are summarized in different sections below. One
commenter neither expressly supported closure -in -place, nor opposed the option. A summary of
that comment follows:
Comment: One commenter indicated that cap -in -place could potentially be a viable
option, but expressed concern regarding the specific proposal for cap -in -place presented by
Duke. He stated his opinion that additional study and safeguards would be needed for this option
to comply with applicable regulations and be safely utilized.
Response: After review of the comments and other relevant data, the Department will
require the removal of all coal ash, which must then be disposed of in lined landfills.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 26

Comment: As noted above, some comments were submitted exclusively registering the
commenters' opposition of closure -in -place. Additionally, a small number of commenters
registered their opposition of cap -in -place, cited specific reasons for their opposition of cap -in -
place, but made no were silent regarding disposition of excavated coal ash. Among these
commenters, the chief reasons cited for opposing cap -in -place were: water quality and health
concerns, concerns regarding Duke's motives in proposing this solution, concerns over the
effectiveness of long-term monitoring, accountability concerns, and/or general fairness concerns
over leaving coal ash in place in some places when it is being excavated at others. One
commenter did not specifically address any of the closure options, but, rather expressed his
general concern with the effects of contamination associated with coal ash.
Response: The Department will require all coal ash at the site to be excavated and
disposed of in lined landfills.
B. Hybrid Option
There were no comments directly addressing either hybrid option.
C. Closure by Removal to a Lined Landfill
1. Comments Supporting Closure by Removal to a New Onsite Landfill
Of the approximately 1200 comments North Carolina Department of Environmental
Quality (NCDEQ) received regarding the five Rogers closure options, the overwhelming majority
of comments were submitted via one of several form emails that supported removal to a lined
landfill. The form email commenters asked for coal ash removal from leaking, unlined pits and
movement to dry lined storage away from waterways and groundwater. Most of these
commenters, however, did not specifically distinguish between moving the coal ash to an onsite
landfill or removal to an offsite landfill.
A large number (approximately 238) of commenters supported closure by removal
specifically to a new onsite dry lined landfill. The vast majority of commenters supporting this
option submitted one of two form letters. Some of these commenters included individualized
comments along with the form letter. A small number of commenters supporting this option did
not utilize either form letter. Those comments are summarized as follows:
Comment: Roughly 70% of comments supporting closure by removal specifically to an
onsite dry lined landfill were submitted using the following form letter:
"1 urge you to require Duke Energy to remove the coal ash from their leaking, unlined pits and to
move it to dry lined storage, which is already available onsite, away from the Broad River and the
groundwater of Cliffside. The Cliffside community has come out time after time over the last
several years to make their concerns about this toxic coal ash clear. It is long past time for DEQ to
listen.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 27

The coal ash pit at Cliffside extends dozens of feet deep into the groundwater table,
violating of federal and state rules. Cap in place in place won't solve these problems, it will just
hide them. Duke's own models show that cap in place will continue polluting groundwater for
500 more years!
North Carolinians deserve better. To comply with the law and protect water quality Duke
must excavate its coal ash now.
Thank you for your consideration."
Response: The Department will require all coal ash at the site to be excavated and
disposed of in a lined landfill. The Department has not yet determined whether disposal shall be
at an onsite landfill, or an offsite landfill.
Comment: A smaller number of commenters supporting closure by removal to an onsite
dry lined landfill submitted the following form email:
• DEQshould require Duke Energy to remove its coal ash from its leaking, unlined pits and
move it to dry, lined storage on its own property — away from the Broad River and out of
our groundwater.
• Duke Energy plans to leave its coal ash sitting in the groundwater at Cliffside, where it
will keep polluting our groundwater, streams and rivers. Recent monitoring shows Duke
Energy is polluting the groundwater surrounding Cliffside with toxic and radioactive
materials. We need cleanup —not coverup!
• The community has come out time after time over the last several years, making clear
that we're concerned about pollution from Duke Energy's coal ash and want Duke Energy
to get its coal ash out of its unlined, leaking pits. It is long past time for DEQ and Duke
Energy to remove the ash.
• Duke Energy is already required to remove its coal ash from eight other communities in
North Carolina and all of its sites in South Carolina, and the governor of Virginia recently
called for all the coal ash to be removed from Dominion's unlined sites —our families and
our community deserve the same protections.
• Duke Energy can dispose all the ash from its leaking ponds onsite in an existing safe,
lined landfill. Ash will not travel through the community or to other communities.
• Duke cannot exaggerate traffic concerns while downplaying the community's real
concern: Duke Energy's water pollution. None of these plans will have a significant
increase in offsite trucking, and only excavation will remove the source of the water
pollution.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 28

• Duke Energy's own experts know that even cap -in -place will involve trucking
construction materials to the site —just like any other construction project. But even
under their estimates, the additional trucking impacts are next to nothing. Duke Energy's
consultant estimates that 97 trucks currently travel near Cliffside on community roads
every day. Excavation would add only nine more trucks on community roads each day,
compared to 13 more trucks on community roads for the duration of the cap -in -place
scenario.
• It is past time for DEQ to listen to the community —not Duke Energy's consultants —
about what our community needs. We need Duke to clean up its coal ash and stop the
water pollution.
Response: The Department will require all coal ash at the site to be excavated and
disposed of in a lined landfill. The Department has not yet determined whether disposal shall be
at an onsite landfill, or an offsite landfill.
Comment: A comment supported excavation of coal ash and relocation to onsite dry
lined storage. They discussed the risks associated with cap -in -place, particularly to vulnerable
populations, as well as stated that cap -in -place violated applicable regulations. They also
expressed concern regarding the data submitted by Duke in favor of cap -in -place.
Response: The Department will require excavation to a lined landfill, but the location of
the landfill has not yet been determined.
Comment: A comment urged the Department to require excavating coal ash and moving
it to lined landfills on Duke's property at all of the sites under consideration. In the letter
supporting this option, the commenter discusses the risks to human and environmental health
associated with cap -in -place, as well as the potential long-term costs of the option.
Response: The Department has determined that excavation to a lined landfill will be
required, but has not yet determined the location of the landfill.
2. Comments Supporting Removal to a Lined Landfill, No Location Specified
Comment: The overwhelming majority of commenters stated in a form email that they
were supportive of closure by removal to dry lined landfill. The comment in that form email
states the following:
"Dear Coal Ash Comment Administrator North Carolina DEQ: Rogers,
The North Carolina Department of Environmental Quality (DEQ) should require Duke
Energy to remove its coal ash from its leaking, unlined pits and move it to dry lined storage away
from our waterways and out of our groundwater. Duke Energy plans to leave its coal ash sitting
in the groundwater at six sites in North Carolina, where it will keep polluting our groundwater,
lakes, and rivers.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 29

Recent monitoring shows Duke Energy is polluting the groundwater at its coal ash ponds
in North Carolina with toxic and radioactive materials. We need cleanup —not coverup!
The communities around the coal ash ponds have come out time after time over the last several
years, making clear that we're concerned about pollution from Duke Energy's coal ash and want
Duke Energy to get its coal ash out of its unlined, leaking pits. It is long past time for DEQ and
Duke Energy to listen to the communities.
Duke Energy is already required to remove its coal ash at eight othersites in North Carolina
and all of its sites in South Carolina —our families and our community deserve the some
protections."
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: Several commenters submitted individual comments urging excavation and
relocation of coal ash to lined landfills, citing water quality concerns, health concerns,
accountability concerns, fairness concerns, and/or concerns relating to Dukes motives in
proposing cap -in -place and/or the data submitted by Duke supporting this option.
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: One commenter urged for excavation and removal to a lined landfill stating
that compliance with applicable regulations is not possible without excavation. He went on to
state that the locations of coal ash impoundments would never have been permitted as
hazardous waste disposal sites. He indicated his belief that classification of these sites as low risk
is inappropriate, and cited numerous fairness and accountability concerns.
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: Citing previous experience with a catastrophic coal spill insisted that NCDEQ
should require Duke Energy to remove its coal ash from its leaking, unlined impoundments and
move it to dry lined storage. There were also concerns for protecting the Catawba River and
downs steam rivers.
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: Another commenter expressed serious concern regarding the closure -in -place
option and provided lengthy commentary on why this option was not viable:
"Cap -in -place is unacceptable for any of the coal ash sites in North Carolina. Any
'solutions' proposed by Duke Energy that do not excavate and move ash to fully lined,
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 30

scientifically designed systems that fully encapsulate coal ash must be rejected. Without
multiple, sealed bottom, side, and top liners, North Carolina's groundwater will always be at risk.
Due to increases in extreme weather, more frequent hurricanes and massive rainstorms,
groundwater models of 100 or 500-year floodplain are obsolete. Given the unpredictable
fluctuations in the water tables and groundwater flows, there is no way that surface capping
without properly engineered underlying bottom liners can protect groundwater in the coming
decades."
The commenter continued by stating: "DEQ should require Duke Energy's new landfills to
go beyond the minimal mandatory protections provided by current regulations. DEQ must carry
out independent studies and obtain recommendations for the best liner technologies, redundant
liners, and with multiple long-term safeguards. Scientifically based placements for baseline and
ongoing groundwater monitoring wells should be established. These must be thoroughly and
constantly monitored — with full, public, transparent, internet accessible, easily available data
from the monitoring results. Ground water and surface monitoring should be ongoing for a
minimum of 50 years ... While transporting existing coal ash dumps away from rivers and
floodplains is essential, every effort should betaken by DEQto ensure that the distances coal ash
is moved is minimized and that the coal ash destinations are always kept on Duke Energy's
property."
The commenter expressed significant concern for worker safety while the above
referenced work is carried out, stating that "During excavation, construction, and filling of the
landfills, all worker safety measures should be taken to prevent a repeat of the serious harms to
worker health from the cleanup crews that worked on the TVA spill.... worker safety, proper fitting
and testing of N95, or better, particulate masks should be required... wherever needed, full
protective suits should be provided."
The commenter concluded: "Once constructed, these new lined landfills should represent
the best technologies and materials available — not materials that create short-term financial
savings. The original existing dumps were disasters for public health, for NC communities, and
for our state's waters. We have this one chance to remediate some of the damages and most
importantly, to safeguard future generations from heavy metal coal ash contamination. Our
state-wide re -design of storage systems for millions of tons of coal ash must be done right this
time."
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: Another commenter who supports removal to a lined landfill urged NCDEQ to
consider conducting its own independent analysis that identifies the safest closure option.
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 31

Comment: A commenter submitted extensive written comments urging NCDEQ to
require the Rogers coal ash basins to be excavated to a lined landfill to protect the environment
and human health.
The commenter claimed coal ash impoundments are not eligible for closure -in -place
under CAMA because cap -in -place will violate state groundwater Rules and the federal CCR Rules.
The commenter sets out the following arguments it believes supports its claim that closure will
violate state Groundwater Rules: 1) Duke Energy's modelling demonstrates it will not meet
groundwater standards if it chooses closure -in -place; 2) Duke Energy's modelling underestimates
the extent of contamination; 3) Duke Energy tested groundwater compliance at the wrong
location; 4) the groundwater rule prohibits closure -in -place because the coal ash will contribute
to violations of the groundwater standard for centuries; and 5) closure -in -place is unavailable
because it will not restore groundwater to the legal standard.
The commenter next claimed that coal ash impoundments at Allen are not eligible for
closure -in -place under the Coal Combustion Residuals (CCR) rule. The commenter supported this
argument by its assertions that: 1) the CCR rules' performance standards require separating ash
from the groundwater and precluding its future impoundment; and 2) the CCR rules' corrective
action requirements preclude closure -in -place.
The commenter continues by arguing that NCDEQ must base its closure determination on
effectiveness and not cost to the polluter. The commenter further maintains that NCDEQ should
reject Duke Energy's "Community Impact Analysis." The commenter claims that Duke's Energy's
report downplays well -established pollution risks and exaggerates the impact on communities of
excavating and trucking material to offsite landfills. Further, they claim that diesel emissions do
not meaningfully distinguish between closure methods and that the report's habitat analysis is
flawed. The commenter concludes by questioning the validity of Duke Energy's closure options
scoring system - and offers its own analysis to demonstrate why it believes Duke Energy
manipulated scores to suit a desired outcome.
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: The same commenter requested that NCDEQ ignore a Duke Energy report on
estimated greenhouse gas emissions associated with various closure options for the six
unresolved coals ash sites. The commenter claimed NCDEQ should disregard this submission
because it was made after NCDEQ's deadline for Duke Energy to submit its materials and outside
the public comment period, thereby denying the public an opportunity to respond to it. NCDEQ
should also disregard this submission because it is irrelevant to the decision facing NCDEQ, which
is to select a closure method that stops the ongoing pollution and continuing threat to our water
resources posed by Duke Energy's leaking coal ash basins.
landfill.
Response: The Department is requiring excavation of coal ash and removal to a lined
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 32

Comment: A commenter stated that the pits should be excavated as soon as possible to
the maximum safe extent with at least twenty-five (25) percent recycled through encasement in
cement bricks, concrete and other methods. The remainder of excavated ash should be moved
into double -lined landfills away from rivers, lakes and aquifers with monitored leak detection
systems. The double -lining would include 2' of clay on the exterior with a durable lining
impervious to water.
Response: The Department has determined that all coal ash at the site must be excavated
and removed to a lined landfill. The Department will consider beneficial use of excavated coal
ash, as well as the location of lined landfills for disposal at a later date.
Comment: A small number of other commenters also suggested the material should be
at least partially recycled.
Response: The Department has determined that all coal ash at the site must be excavated
and removed to a lined landfill. The Department will consider beneficial use of excavated coal
ash, as well as the location of lined landfills for disposal at a later date.
Comment: Several comments were received in the form of YouTube testimonials
following NCDEQ's Environmental Justice Advisory Board meeting in Wilmington, NC. Links to
each these testimonials follow:
Caroline Armijo - ACT Member https://youtu.be/ciag3oPl4gU
Johnny Hairston - resident in harm's way of basin failure https://youtu.be/6iK1sbVO058
Rev. Gregory Hairston — leader/resident in close proximity https://youtu.be/IV9crtEyTJY
John Wagner - ACT Member https://youtu.be/IV9crtEyTJY
Frank Holleman - lead attorney of SELC https://youtu.be/elwPWPYb3Uc
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
Comment: Four additional videos were submitted regarding the impact of coal ash spills:
At What Cost (2014) https://youtu.be/rraUoadgr8o
Danielle Bailey -Lash on CNN https://Voutu.be/OCTU-CUoQzQ
A Time to Sing (Abridged) (August 2018) https://youtu.be/HQFYKBaf4NQ
A Day of Prayer (February 2019) https://youtu.be/agRzScT BEs
Response: The Department will require that all coal ash at the site be excavated and
relocated to lined landfills.
ROGERS ENERGY/CLIFFSIDE CLOSURE DETERMINATION - APRIL 1, 2019 - 33

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
April 4, 2019
Subject: Response to the Optimized Interim Monitoring Plans (IMP) for 14 Duke Energy
Facilities - Modification Request Annual Reports - Modification Request
Dear Mr. Draovitch:
On March 20, 2019, the North Carolina Department of Environmental Quality Division of Water
Resources (Division) received the proposed Optimized IMP for 14 Duke Energy Facilities -
Modification Request Annual Reports - Modification Request (Modification Request). This letter
requested changes to direction provided to Duke Energy by the Division in the December 21, 2018
correspondence concerning the Optimized IMP along with proposed changes to the scope and/or
reporting schedule for Interim Action Effectiveness Reports for the Asheville, Belews Creek, and
Sutton facilities.
Modification of Interim MonitoringPlan
lans
The Division has reviewed and hereby approves Modification Request for implementation of the
Optimized IMPS apart from the following which require justification subject to approval. The
following changes were noted from the previous optimized IMPs approved by the Division on
December 21, 2018.
• Asheville
O Wells EXT-D and MW-8BR were moved from quarterly sampling to water
level only. Please provide justification for this change.
• Belews Creek
O Wells AB-1BRD, AB-2BR, AB-2BRD, and AB-3BRD were removed from
quarterly sampling. Please provide justification for this change.
North Carolina Department of Environmental Quality I Division of Water Resources
QE J 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919.707.9000

• Roxboro
o Wells ABMW-7BRLL, MW-01BRL, MW-108BRL, MW-205BRL, and
MW-208BRL were removed from quarterly sampling. Please provide
justification for this change.
IMP Annual Monitoring Reports
The Division has reviewed and hereby approves the Modification Request concerning the due
dates for the IMP Annual Monitoring Reports. The due dates for these reports shall be as follows:
• April 30, 2019 —Allen, Belews Creek, Cliffside, Marshall, Mayo, and Roxboro.
• July 31, 2019 — Asheville, Buck, Cape Fear, Dan River, H. F. Lee, Riverbend, Sutton,
and Weatherspoon.
Interim Action Effectiveness Reports
The Division has reviewed and hereby approves Modification Request concerning Interim Action
Effectiveness Reports. The due dates for these reports shall be as follows:
May 15, 2019 — Sutton
July 31, 2019 — Asheville and Belews Creek
Revisions to the tables in the Modification Request are expected based on the detailed review items
documented in this letter unless compelling rationale is provided to substantiate these changes to
the December 21, 2018 Optimized IMP direction. The Division may require changes to the content,
format and schedule of the IMP Annual Monitoring Reports and Interim Action Effectiveness
Reports after review of the pending submittals.
If you have any questions, please contact Steve Lanter (Central Office) at [phone].
Sincerel , l
Jon Risga a d, Chief
Animal Feeding Operations and Groundwater Section
cc: WQROS Regional Offices
WQROS Central File Copy

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
Paul Draovitch
Senior Vice President
Environmental, Health, & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
April 5, 2019
Subject: Final Comprehensive Site Assessment and Corrective Action Plan Approvals for
Duke Energy Coal Ash Facilities
Dear Mr. Draovitch:
The purpose of this letter is to establish submittal dates for Comprehensive Site Assessments (CSAs)
and Corrective Action Plans (CAPS) for all 14 Duke Energy Coal Ash Facilities (Facilities). The
schedule provided includes:
• Restatement of schedules for the six Facilities that were established in the North Carolina
Department of Environmental Quality (DEQ) October 8, 2018 letter.
• Clarification that the March 31, 2020 submittal date for evaluation of sources at the Facilities
that are not associated with the coal ash impoundments is for CSA Reports.
• Establishment of CSA and CAP submittal dates for the remaining eight Facilities considering
the November 5, 2018 Duke Energy proposed schedule and additional information regarding
justification for proposed submittal dates.
• List of primary sources to be included in each facility CSA or CAP.
The following is the approved schedule for the submittal of CSAs and CAPs for each facility.
Allen Steam Station
• Due December 1, 2019 — Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments including the coal pile, retired ash basin
landfill, two structural fills, and two dry ash storage areas.
• Due March 31, 2020 — CSA for primary and secondary sources not associated with
impoundments including the gypsum pad.
-eo:: f Q. E� N
���
North Carolina Department of Environmental Quality
217 West Jones Street 1 1601 Mail Service Center I Raleigh. North Carolina 27699-1601
919.707.8600

Asheville Steam Electric Plant
• Due June 1, 2020 —Updated CSA for impoundments and other primary and secondary sources
including the raw coal pile.
• Due March 1, 2021 — Updated CAP for impoundments and other primary and secondary
sources.
Belews Creek Steam Station
• Due December 1, 2019 —Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments including the Pine Hall Road Landfill.
• Due March 31, 2020 — CSA for primary and secondary sources not associated with
impoundments including the structural fill and coal pile.
Buck Combined Cycle Station
• Due October 1, 2020 — Updated CSA for impoundments and other primary and secondary
sources including the coal pile.
• Due July 1, 2021— Updated CAP for impoundments and other primary and secondary sources.
Cape Fear Steam Electric Plant
• Due September 1, 2020 — Updated CSA for impoundments and other primary and secondary
sources including the former coal pile storage areas.
• Due June 1, 2021— Updated CAP for impoundments and other primary and secondary sources.
James E. Rogers EnerRv Com lex
• Due December 1, 2019 — Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments including the ash storage areas and newly
identified source east of Unit 6 and west of Suck Creek.
o Duke Energy has indicated that investigation of the newly identified source east of Unit
6 and west of Suck Creek may require additional well installation that would require
that the CAP due December 2019 not include this source area. In the event that this is
the case, Duke shall notify DWR, and provide a summary of up-to-date findings so an
appropriate schedule for this area can be established.
• Due March 31, 2020 — CSA for primary and secondary sources not associated with
impoundments including the raw coal piles north of Unit 6, switchyard ash disposal area, and
gypsum pile.
Dan River Combined Cycle Station
• Due July 1, 2020 — Updated CAP for impoundments and other primary and secondary sources
including the former coal yard.
H. F. Lee Energy Com lex
• Due October 1, 2020 — Updated CSA for impoundments and other primary and secondary
sources including the coal staging area/coal pile and lay of land area.
• Due July 1, 2021 — Updated CAP for impoundments and other primary and secondary sources.
Marshall Steam Station
• Due December 1, 2019 — Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments including the coal pile and gypsum pile.
ceo:f RE Q�
North Carolina Department of Environmental Quality
217 West Jones Street 1 1601 Mall Service Center I Raleigh, North Carolina 27699-1601
919.707.8600

Mavo Steam Electric Plant
• Due December 1, 2019 — Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments which may include the active coal storage
pile areas.
• Due March 31, 2020 — CSA for primary and secondary sources not associated with
impoundments including the gypsum pad and low volume wastewater pond.
Riverbend Steam Station
• Due May 1, 2020 —Updated CAP for impoundments and other primary and secondary sources
including the former coal yard.
Roxboro Steam Electric Plant
• Due December 1, 2019 — Updated CAP for impoundments and other primary and secondary
sources hydrologically connected to impoundments including the West Ash Basin Extension
Impoundment and associated discharge canal and the East Ash Basin Extension Impoundment
and associated discharge canal.
• Due March 31, 2020 — CSA for primary and secondary sources not associated with
impoundments including the coal storage pile.
L. V. Sutton Ener;;y Complex
• Due May 1, 2020 — Updated CAP for impoundments and other primary and secondary sources
including the former ash disposal area, former process area, and former coal stockpile area.
W. H. Weatherspoon Power Plant
• Due June 1, 2020 — Updated CSA for impoundments and other primary and secondary sources
including the coal storage area and cooling pond.
• Due March 1, 2021 — Updated CAP for impoundments and other primary and secondary
sources.
Any required assessment of source areas not permitted by the Division of Water Resources and not
hydrologically associated with the CCR impoundments (such as a solid waste landfill) will be at the
discretion of the permitting division/section of DEQ. If you have any questions, please contact me at
[phone].
Sincerely,
Sheila Holman
Assistant Secretary for Environment
Cc: Bill Lane
Ed Mussler, DWM
Jon Risgaard, DWR
George Eller, DEMLR
WQROS Regional Office Supervisors
DEQ Central File Copy
PO V_.;
North Carolina Department of Environmental Quality
217 West Jones Street 1 1601 Mail Service Center I Raleigh, North Carolina 27699-1601
919.7078600

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
May 23, 2019
Subject: Revised Background Threshold Values for Soil
James E. Rogers Energy Complex, Marshall Steam Station, Mayo Steam Electric Plant,
and Roxboro Steam Electric Plant
Dear Mr. Draovitch:
In the May 14, 2018 North Carolina Department of Environmental Quality's (DEQ) Division of Water
Resources (DWR) letter, DEQ determined select Background Threshold Values (BTVs) were
unacceptable for the subject sites. The Soil BTVs were further evaluated by the respective DWR
Regional Offices following protocols consistent with the Revised Statistical Methods for Developing
Reference Background Concentrations for Groundwater and Soil at Coal Ash Facilities dated May 26,
2017 (and additional guidance provided in the December 7, 2017 email from Steve Lanter to Ed
Sullivan and John Toepfer). The review process included correspondence with Duke Energy staff
regarding BTV calculations.
As a reminder, soil BTVs that are calculated above the DEQ Division of Waste Management
Inactive Hazardous Sites Branch's (IHSB) Preliminary Soil Remediation Goals (PSRG) for the
protection of groundwater shall become the BTVs for use in developing an appropriate site -
specific corrective action strategy. For compounds that do not have an established PSRG but do
have a groundwater standard (i.e. chloride and sulfate) pursuant to 15A NCAC 02L .0202, the
calculation provided in the PSRG table is used to establish a PSRG if the required site -specific
data are available. The PSRG table can found under the IHSB website at:
h_ttps://deg .nc.Lov/about/divisions/waste-management/waste-manat,ement-permit-
ruidance/inactive-hazardous-sites- ,,uidance-documents.
The following soil BTVs for each facility are determined to be acceptable by DWR. Where
calculated BTVs are below the PSRG, the PSRG is provided in parentheses for use in developing
an appropriate corrective action strategy:
North Carolina Department of Environmental Quality I Division of Water Resources
E� 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
rxx�m��xnu
919.707.9000

James E. Rogers EneM Complex
• Antimony — 0.27 mg/kg (PSRG is 0.9 mg/kg)
• Boron — 21.7 mg/kg (PSRG is 45 mg/kg)
• Cadmium — 0.03 mg/kg (PSRG is 3 mg/kg)
• Mercury — 0.034 mg/kg (PSRG is 1 mg/kg)
• Molybdenum — 1.2 mg/kg (PSRG is 7.1 mg/kg)
Marshall Steam Station
• Sodium — 394 mg/kg
Mayo Steam Electric Plant
• Manganese —1,894 mg/kg
• Sodium — 832.7 mg/kg
• Thallium — 0.406 mg/kg
Roxboro Steam Electric Plant
• Manganese — 531.8 mg/kg
• Nitrate (as N) — 0.7 mg/kg
This letter does not address groundwater BTVs that were found unacceptable in the May 14, 2018
letters for the subject facilities.
If you have any questions, please contact the applicable DEQ Regional Office or Steve Lanter (Central
Office) at [phone].
Sincerely,
Lin a Culpepper, Director
Division of Water Resources
cc: ARO, MRO, and RRO WQROS Regional Office Supervisor
WQROS Central File Copy

ROY COOPER
Governor
HCHAEL S. REGAN
Secretory
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Envkmmental Qual ty
September 10, 2019
Subject: Duke Energy Interpretation of Corrective Action Plan Content Guidance (January 23,
2019) — North Carolina Department Environmental Quality Response and Conditional
Approval
Dear Mr. Draovitch:
On January 23, 2019, the North Carolina Department of Environmental Quality's (DEQ) Division of Water
Resources (DWR) received the Duke Energy Interpretation of Corrective Action Plan (CAP) Content
Guidance Provided by the DEQ. That document describes Duke Energy's proposed approach for preparing
the groundwater CAPS within the structure of the DWR's guidance titled "CAP Content for Duke Energy
Coal Ash Facilities" dated April 27, 2018. DWR has reviewed the proposed approach regarding CAP
development and conditionally approves its implementation with the following considerations and
conditions: In addition, DWR has provided the attached comments on Duke Energy's Supporting Rationale
for the Proposed Interpretations and Adjustments to the CAP Content Guidance that was produced with
respect to the April 27, 2018 letter (Attachment 2).
• Section 1.C.b. — Keep text that references the Notice of Regulatory Requirements (NORR).
Information related to the NORR needed to address DEQ Comprehensive Site Assessment (CSA)
Update comments shall be provided in the body of the CAPS in a comprehensive manner to
adequately evaluate site conditions and to refine remedial design to facilitate decision making
regarding corrective action.
• Section 1.D. — The proposed additional text is acceptable; however, the criteria that will be used
for evaluation and selection of remedial alternatives in the CAPS should be provided in Section 6.
• Section 1.E.b. — Duke Energy's clarification is acceptable, however, please acknowledge and
identify any other primary and secondary sources, non -coincident with the ash basins, that are on -
site and are currently or were formerly under the jurisdiction of DEQ.
• Sections 4.B. and 4.C. — A discussion of background concentrations in other similar settings is
acceptable; however, site -specific data will be the primary consideration for determination of
background threshold values (BTVs) for both soil and groundwater.
MENorth
� Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
mra� /'�� 919.707.9000

• Section 4.D. — Application of United States Environmental Protection Agency Nationally
Recommended Water Quality Criteria for Aquatic Life & Human Health by the DEQ is authorized
in the context of using narrative regulations for toxic controls where no surface water quality
standard has been adopted into state regulations. This is consistent with state authority under the
Clean Water Act, as well as state administrative code with respect to corrective action. DEQ will
work with Duke Energy to determine the appropriate response to exceedances of the 15A NCAC
02B surface water quality standards where applicable.
• Section 5 — Please include a 3-dimensional figure that illustrates groundwater impacts.
• Summary of Potential Receptors/Section 6 — The process of identifying potential receptors should
acknowledge that the hydraulics and groundwater/surface water flow patterns near the ash basins
have potentially changed over the years due to mounding and other site conditions; therefore, the
area that may have been impacted by may be more extensive than the area affected by current site
operations.
• Section 6 — Constituents of interest (COIs) that are subject to corrective action shall be constituents
with concentrations greater than the 15A NCAC .02L Groundwater Standards, Interim Maximum
Allowable Concentrations, or BTVs at or beyond the point of compliance, as well as, any
constituents within the compliance boundary that are predicted to cause a violation of any standard
in adjoining classified groundwaters, as directed by 15A NCAC .02L .0107(k). This concept shall
be reflected in any revised text.
• Section 6.A. — While the overall concept for data reduction to focus CAP development is
acceptable, sufficient data must be included to justify any proposed corrective action and an
agreement must be reached between Duke Energy and the DWR Regional Offices concerning
which COIs to address for corrective action. Also, providing data or responses to CSA Update
comments only in an appendix is not acceptable.
• Section 6.A.a.vi.3. — Consideration of constituents that will be mapped in the CAPS shall be based
on a review of site factors that affect flow and transport, including geochemical conditions, as well
as, public concern. The specific constituents that will be mapped in the CAPs shall be determined
by consensus between Duke Energy and the DEQ Regional Offices. If constituents display a
limited or discontinuous distribution that does not lend well to conventional mapping, then a
discussion of related site conditions should be provided in a manner that could understood by the
general public.
• Section 6.A.b. — The June 2019 cut-off date for inclusion of data into a CAP is acceptable for sites
where document submittals are scheduled for December 2019. However, CAPs due at later dates
should have different data cut-off dates based on Duke Energy's internal review process.
• Section 6.A.b.ii. —All 15A NCAC .02L Groundwater Standard exceedances should be
acknowledged and discussed. An agreement must be reached between Duke Energy and the
respective DWR Regional Offices concerning which COIs to address for corrective action.
• Section 6.A.c.i-ii — Removal of this section is acceptable. Under Section 6.D.a.i.ii, also list the
maximum concentrations of the COIs within and beyond the point of compliance for each media
(soil, groundwater, sediment, etc.).

• Section 6.B.a. — The process ofidentifying identifying potential receptors should acknowledge that the
hydraulics and groundwater/surface water flow patterns near the ash basins have potentially
changed over the years due to mounding and other site conditions, and therefore the area that may
have been impacted by past site operations may be more expanded than current site operations.
• Section 6.D.a.ii. — List the maximum concentrations of the COIs within and beyond the point of
compliance for each media (soil, groundwater, sediment, etc.).
• Section 6.D.a.iii. — Keep this Section and provide a succinct summary of modeling results,
including modeled concentrations above the 2L standards at or beyond the point of compliance for
the modeled time frame.
• Section 6.E.b and 6.E.b. iv. — Provide enough information and detail for the various remedial
alternatives considered to facilitate review. A higher level of cost detail shall be provided for the
remedial alternative selected in order to provide adequate information for decision making.
Otherwise, additional documentation may be required before an alternative is approved.
• Section 10 —Where applicable, isoconcentration maps shall provide mapping of analytical results
to background or non -detect levels to depict concentration gradients related to COI distribution. In
addition, all data points must be illustrated on maps. This level of detail is needed to evaluate
remedial design and address CSA Update document comments.
• Section 11. — Final content concerning appendices should be based on an agreement between Duke
Energy and the DEQ Regional Offices and should include all supporting documentation for
remedial alternative design.
Please include this correspondence as part of the CAP Update documents. If you have any questions, please
feel free to contact Steve Lanter (Central Office) at [phone].
Sincerely,
Ji �reggson, Deputy Director
Division of Water Resources
Attachments: (1) Duke Energy Interpretation of Corrective Action Plan Content Guidance Provided by
the North Carolina Department of Environmental Quality — January 23, 2019
(2) Supporting Rationale for Proposed Interpretation and Adjustments to the Corrective
Action Plan Content Guidance (NCDEQ April 2018) by Duke Energy January 2019
cc: WQROS Regional Office Supervisors
WQROS Central File Copy

ROY COOPER.
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Director
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
NORTH CAROLINA
Environmental Quality
October 24, 2019
Subject: Approach to Managing Constituents of Interests for Purposes of Corrective Action
Plans
Dear Mr. Draovitch:
On September 4, 2019 Duke Energy presented a Constituent of Interest (COI) Management Plan (Plan) to
facilitate Corrective Action Plan (CAP) development required at its coal combustion residuals (CCR)
facilities. In lieu of a document to review, the North Carolina Department of Environmental Quality (DEQ)
has reviewed the content of the presentation to develop a position regarding the subject matter. The COI
Plan as presented to date is conditionally acceptable with notable revisions described in Attachment 1.
These revisions will assist Department review and ensure a consistent approach across the CCR facilities.
DEQ staff welcome the opportunity to discuss related COI Plan issues with Duke Energy, including
attending other facility -specific presentations. If you have questions or concerns regarding the
Department's position relative to the COI Plan provided in this correspondence, please contact Steve Lanter
in the DWR Central Office at [phone] and he will coordinate with the respective Regional Offices
to initiate discussion.
Sincerely,
Jtl�son, Deputy Director
Division of Water Resources
Attachments
Attachment 1 - Approach to Managing Constituents of Interests for Purposes of Corrective Action Plans
cc: WQROS Regional Offices (electronic copy)
GWRS Central File Copy
North Carolina Department of Environmental Quality 1 Division of Water Resources
�
D_E � 512 North Salisbury Street 1 1636 Mail Service Center I Raleigh, North Carolina 27699-1636
�0-ft 919.707.9000

October 22, 2019 Attachment 1- Approach to Managing COls for Purposes of CAPS
Attachment 1
Approach to Managing Constituents of Interests for Purposes of Corrective Action Plans
On September 4, 2019, Duke Energy presented a Constituent of Interest (COI) Management Plan (Plan)
for Corrective Action Plan (CAP) development required at its coal combustion residuals (CCR) sites.
The presented Plan is conditionally acceptable with notable revisions described below. These revisions
Will assist Department review and ensure a consistent approach across coal ash facilities.
Framework as Presented by Duke on 9/04/19. As described in the 9/04/19 Duke presentation, COls
that occur above the criterion (defined as the greater of 15A NCAC 02L standards [02L], interim
maximum allowable concentrations [IMACs], or background threshold values [BTUs]) at/beyond the
compliance boundary (CB) will be identified for corrective action. Depending on their
observed/modeled occurrence and distribution and a "groundwater (GW) exceedance ratio", Duke
Energy proposes to map some COIs; other CON will, as proposed, be unmapped and only listed in a
table. The typical mobility of each COI will be described along with conditions that affect its mobility.
Attenuation mechanisms will be described for each COI along with the expected long-term stability of
those mechanisms.
Framework Response by DWR with Revisions. This COI Management Framework is a process
developed to facilitate corrective action planning. The Framework helps identify the areas and COls in
need of corrective action and the potential remedies that could be effective. Corrective actions are
being implemented in conjunction with and to support and augment basin closures. When CBs are
modified or expire, and compliance has not been achieved in an area no longer covered by a CB,
corrective actions will be required in those areas. Corrective actions may or may not need to be
"active" depending on factors evaluated in the Framework such as, for example, mobility of the CON in
question, stability of attenuation mechanism(s), remediation goals for the COls, etc. Rather than
computing a maximum mean and a GW exceedance ratio, use of a lower confidence limit (LCL)95 (95%
lower confidence limit)' is a more appropriate metric to identify and document areas in need of
corrective action. For each monitoring well, Duke Energy shall compute an LCL95 for the COI in
1 See, for example, United States Environmental Protection Agency (EPA) Unified Guidance (March 2009) and ProUCL
Technical guidance (2013), including discussion of parametric and non -parametric 95% LCLs. Note that if the well
sample dataset is shown to be trending for a given COI, an LCL95 may be computed on the trendline.
Page 1 of 4

October 22, 2019 Attachment 1- Approach to Managing COls for Purposes of CAPs
question by using data from all sample events at the wel12. If the computed LCL95 exceeds the
applicable criterion then that well -COI would be identified in the CAP as a localized area in need of
corrective action. If the localized area for the identified COI is isolated and does not represent a larger
scale plume, it may be mapped accordingly in the CAP by simply showing a large scale plan view map
with the well that contains the exceeding LCL95, along with the LCL95 value, representative pH and Eh
values, Kd, ratio of species concentrations for the C01 in question (if applicable and assuming
speciations have been measured/computed), and a dashed line containing the area in need of
corrective action. As described in the 9/4/19 presentation, a table(s) will also be provided containing
the list of CON, and their corresponding typical speciation (anion, cation, neutral), mobility under
acidic/alkaline conditions, mobility under reducing/oxidizing conditions, localized conditions that affect
mobility, propensity for sorption, ion exchange, and (or) precipitation, and expected long term stability
of the attenuation mechanisms. Influence of hyporheic zone on geochemical conditions and COI
mobility, if applicable, should also be considered/discussed, as should the influence of potential
surface water mixing on geochemical conditions and mobility during storm -induced rises in surface
water levels that can, in some cases, reverse groundwater gradients. The extent of boron above
background is to be shown on all maps as an approximate extent of hydraulic influence from the basin.
If the modeled boron plume has not yet stabilized (is continuing to move in time) then the extent of
boron above background at future year 2120 should also be shown on the maps to indicate the
predicted future extent of basin influence.
Transects referred to in the CAP shall be shown (a) in a plan view map along with the observed head
contours and corresponding flow lines, (b) in a plan view map along with modeled head contours, and
(c) in cross section with modeled head contours and velocity vectors.
Dissolved Groundwater Concentrations. Unfiltered (total) concentrations of constituents are
measured for most groundwater samples. However, for geochemical modeling purposes, dissolved
concentrations must be used in the input file of the computer code. For each CCR basin, a conceptual
2 Rather than using only data from 2018 to 2019 as presented by Duke, data from all sample events should be used. If
a technical reason exists to omit a portion of the historic dataset, an appendix may be provided that includes the well,
all values in the historic record for the COI in question, the values that should be omitted, and rationale for the
omission (e.g. early break-in issues, COI concentration -time trends, pH or turbidity issues, etc.). Future monitor wells
would also undergo LCL95 computation to identify additional areas in need of corrective action.
Page 2 of 4

October 22, 2019 Attachment 1- Approach to Managing Cols for Purposes of CAPS
geochemical model will be developed to represent current conditions and estimate how COI
concentrations may change in the future in response to changes in environmental conditions, such as
redox change due to decanting/dewatering. The results of ion speciation and mineral equilibrium
calculations from groundwater data along flowpaths from the source areas to downgradient locations
will be used to develop the geochemical conceptual site models. Dissolved concentration data for all
parameters (major/minor ions and COls) must be collected from the monitoring wells along the
flowpaths to develop these models. This will also be done for areas where anomalous geochemical
conditions occur such as the low pH area at Allen. In most cases, dissolved sampling conducted under
the Interim Monitoring Plans will be sufficient for modeling purposes.
Valence State Measurements. Several of the potential CON are redox-sensitive and occur in more
than one valence state [e.g., As (III,V), Se (-II, 0, IV, VI), Fe {II,III), Mn (II, III, IV)]. Because of the
perceived difficulty of preserving samples in the field for redox species measurement in the laboratory,
redox speciation is being calculated from the measured pH and Eh using a geochemical modeling code.
This method assumes redox equilibrium and may not always be appropriate. In situations where
anomalous groundwater concentrations of a redox-sensitive COI are present, it would be beneficial to
conduct sampling and laboratory analyses for the redox species of the COI to determine if speciation is
a factor leading to the anomalous behavior. This would require appropriate preservation of water
samples in the field for lab measurements of the specific redox species.
Additional sampling and analysis of redox species in selected wells would help to demonstrate that the
modeled speciations that have been calculated under an assumption of equilibrium conditions are
appropriately determined. The number and location of wells used for this purpose should be
appropriate to demonstrate confidence in the modeling approach, input data, and results.
COI Identification. The Plan process discussed in the meeting included a comparison of groundwater
concentrations to relevant regulatory criteria in order to select Cols based on exceedances of their
respective criteria. Consideration should also be given for those constituents that do not currently
exceed their criteria but may feasibly exceed that criteria in the future if environmental conditions
change. For example, if the arsenic criterion is 10 µg/L and the measured groundwater concentration
is 5 µg/L, then arsenic would be included in predictive geochemical modeling to determine if corrective
Page 3 of 4

October 22, 2019 Attachment 1- Approach to Managing COls for Purposes of CAPs
actions produce conditions that elevate the arsenic concentration above its criterion. For practical
purposes, constituents that are currently measured in a groundwater well beneath or downgradient of
a basin at an LCL95 concentration at or above 50% of the criterion (i.e. LCL95 >= COI criterion x 0.5)
would be included in the modeling of future conditions to estimate whether or not those future
conditions increase the groundwater level to a concentration greater than the criterion.
Conclusions and Discussion in CAPS. Findings and conclusions presented in the CAPS should pertain
to a specifically identified local area beneath and (or) downgradient of a basin. Each area identified for
corrective action, whether it be a plume, an isolated, localized area, or an anomalous area, should be
discussed individually and specifically. For consistency in the CAP, discussions and tables related to COI
management generally should refer to the LCL95 (rather than the mean or geomean) and the COI
criterion (rather than 2L, IMAC, or background). Where the CAP discusses performance or
effectiveness monitoring that will be conducted as part of corrective action implementation, an upper
confidence limit 95% (UCL95) would be the appropriate evaluation metric rather than the LCL95 (i.e.
corrective action continues until the UCL95 is below the cleanup criterion').
s See EPA (2018) Groundwater Statistics Tool — User's Guide.
Page 4 of 4