NC0024406_BCSS_Appendix A_20191231

Corrective Action Plan Update December 2019
Belews Creek Steam Station SynTerra
APPENDIX A
REGULATORY CORRESPONDENCE
NCDENR. August 13, 2014. Notice of Regulatory Requirements Letter
AECOM. August 5, 2016. Dam Safety Repair Record Documentation, NCDEQ
State Dam ID: STOKE-116, Belews Creek Steam Station
NCDEQ. July 7, 2017. Background Soil and Groundwater Dataset Review
NCDEQ. September 1, 2017. Approval of Provisional Background Threshold
Values
NCDEQ. September 1, 2017. Provisional Background Threshold Value
Approval Attachments
NCDEQ. April 26, 2018. Review Comments for 2017 Comprehensive Site
Assessment Update
NCDEQ. April 27, 2018, CAP Content for Coal Ash Facilities FINAL
NCDEQ. May 14, 2018. Approval of Revised Background Threshold Values
Letter and Attachment
NCDEQ EMAIL. May 23, 2018. Draft Comments for Discussion Friday
NCDEQ. November 13, 2018. Final Classification of CCR Surface
Impoundment
NCDEQ. January 2019. Position Supporting Rationale for Proposed Duke
Energy Interpretation and Adjustments to the Corrective Action Plan
Content Guidance
NCDEQ. April 1, 2019. Final CCR Surface Impoundment Closure
Determination Report
NCDEQ. April 4, 2019. Final Response to Proposed IMP Changes
NCDEQ. April 5, 2019. Final CSA and CAP Schedules
NCDEQ. September 10, 2019. Duke Energy Interpretation of CAP Contents
Guidance
NCDEQ. October 24, 2019. Approach to Managing COIs for CAPS

A 4
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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

►4XOM
August 5, 2016
Mark Patrick
Eric Kinstler
Dan Albert
Duke Energy
400 South Tryon Street
Charlotte, North Carolina 28202
Re: Record Documentation
BC-6/4 — Weighted Filter Overlay Project
NCDEQ State Dam ID: STOKE-116
Duke Energy — Belews Creek Steam Station
Stokes County, North Carolina
Gentlemen:
AECOM 919-461-1100 tel
1600 Perimeter Park Drive 919-461-1415 fax
Suite 400
Morrisville, NC 27560
www.aecom.com
In accordance with the Certificates of Approval to Repair — Scope 2 and Scope 4 issued by the North
Carolina Department of Environment and Natural Resources (NCDENR) on January 30, 2015 and
April 1, 2015, respectively, AECOM is submitting record documentation for the completion of
construction for the above referenced project. Two copies of the record documentation are to be
provided to the North Carolina Department of Environmental Quality (NCDEQ), Division of Energy,
Mineral, and Land Resources for review and consent in accordance with stipulation 4 of the
Certificates of Approval.
Please note that the permit drawings were prepared by URS Corporation. URS is now AECOM
Technical Services of North Carolina. The title sheet of the attached record drawings has not been
modified to reflect the new company name, but the Engineer of Record is the same as designated in
the above referenced NCDENR Certificates of Approval.
The repairs for this dam, in compliance with the Dam Safety Law of 1967, included the addition of a
seepage collection and filter system and weighted earthfill buttress, among other items. The repairs
included the following tasks:
• Grub recently cleared areas of the Active Ash Dike embankment and repair areas of minor
erosion.
• Removal of stumps of felled trees and woody vegetation.
• Haul and disposal of grubbing debris and materials remaining from the tree felling operations.
• Installation and maintenance of temporary erosion and sedimentation control devices as
indicated on the erosion and sediment control plan and details, and implementing/adhering to
requirements (including self -inspection and reporting) of stormwater general permit
NCG0100000 for construction activities.
• Demolition of existing flumes, concrete ditches, and other surface features to accommodate
the new construction, including removal and incorporation of several previous seepage/slope
repair areas into the weighted filter overlay.
• Installation of an aggregate seepage collection and filter overlay system and earthfill buttress
(weighted filter overlay) graded to match previous embankment slopes.
• Installation of 8-inch solid and perforated pipes to transport seepage captured within existing
horizontal drains and the new filter aggregate, respectively. These pipes constitute a closed
system within the dam and discharge downstream at the newly installed Seepage Discharge
Structure. Cleanouts are provided at numerous locations for inspection and maintenance.

►4XOM
• Installation of two new trapezoidal flumes to measure/monitor seepage flows conveyed by the
weighted filter overlay, including one '/z-inch flume within the left abutment toe ditch and one
2-inch flume at the Seepage Discharge Structure.
• Installation of a new riprap lined outlet channel discharging into the Unnamed Tributary to the
Dan River.
• Installation of stormwater culverts, riprap lined ditches, seepage collection berm, and
concrete ditch (at the new 700 berm).
• Rehabilitation of the site east access road, and construction of new Flume Access Road and
700 Berm Access Road.
• Abandonment and re -installation of several piezometers and one set of replacement paired
monitoring wells.
• Seeding, fertilizing, and mulching all disturbed areas as indicated on the plans.
Please refer to the attached record drawings for repair features. The record drawings include as -built
plans prepared by AECOM representing the finished construction conditions at the site and an as -
built survey plan set prepared by Fleming Engineering, Inc. (FEI). FEI completed surveying
throughout construction of the project and their survey plan represents constructed and final grades
of the ground features and the weighted filter overlay components. The AECOM as -built plans were
developed by documenting revisions to the original Issue for Construction (IFC) drawings issued on
April 6, 2015. The revisions (noted on applicable IFC drawing sheets) were made as changes to the
project/IFC drawings were implemented during construction. It should be noted that no revisions to
the project/IFC drawings changed the intent or overall function of the original design.
As the Engineer of Record, Douglas W. Carr, PE, believes that the repair work completed has
accomplished the goal of bringing the Active Ash Pond STOKE-116 Ash Dike in compliance with GS
143-215.29 and NCAC 15A-2K.0203, .0212, .0215, and .0216, that construction of the repairs was
completed in general accordance with the approved drawings and specifications, and that the dam is
safe as modified and repaired. Any known modifications to the approved plans and specifications
have been noted herein.
Please do not hesitate to call the undersigned at 919-461-1230 (office) or 919-723-6240 (mobile) if
you have any questions or comments on this submittal.
Sincerely,
AECOM Technical Services of North Carolina, Inc.
Douglas W. Carr, PE
Engineer of Record
Cc: Gabe Lang — AECOM
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Attachments: Record As -Built Plans (2 copies) dated 8/5/2016
P&J As -Built Survey Data dated 7/29/2016
Record As -Built Specifications
Page 2 of 2

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

Water Resources
Environmental Quality
September 1, 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 Belews Creek Steam
Station
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 facility. 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. It should be noted that Duke Energy supplied additional data on
August 8, 2017, and September 1, 2017, on which their final calculations were based.
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
periodic review will established by DWR at a later date and any revised PBTVs will be subject to
approval by the DWR's Director.
State of North Carolina I Environmental Quality I Division of Water Resources
Water Quality Regional operations Seetiou
1636 Mail Service Center I Raleigh, North Carolina 27699-1636
919-707-9129

Along with the specific comments provided on the attachments, DWR offers the following general
comments with regards to the PBTVs
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 justifications shall be provided.
The PSRG for Chromium shall be the more conservative value for Chromium (VI) which
is 3.8 mg/kg.
If you have any questions, please contact Shuying Wang (Winston-Salem Regional Office) at
[phone] or Steve Lanter (Central Office) at [phone].
Sincerely,
S. Jay Zimmerman, P.G., Director
Division of Water Resources
Attachments
cc: WSRO WQROS Regional Office Supervisor
WQROS Central File Copy

Belews Creek Steam Station - Groundwater Provisional Background
Threshold Values
Parameter
Reporting
Units
Duke f ne_ra.( alauLaed l'D i Vs _
_}low l nit T _
Shallow DV,P Sednn6
15A NCAC 02L
Standard or
IMAC
DWR Concurrence(Acceptable/Not Acceptable)
Comments
Flow Unit
Shallow
Deep
Bedrock
H
S.U.
5.1-6.03 5.19-7.02 6 3-6 5
-+ - -
22 9 _ 63' _y 3LJ -_
860 140 1 _ Leo
I__ I1___ I 0.5 _
_ i _ _ 1 _ _0. 51
58 12.6 6..2
0_362 0.219 0.2
22_3 _ 629 _ .6
ND IT_ %1) _ 5_n __
1 _ _ 1 - i 0 08
6.5-8.5
Acceptable
Acceptable
Acceptable
Not evaluated because the values me below the groundwater standards or no standard is established.
Alkalinitymg/L
NE
Acceptable
Acceptable
Acceptable
Alumina
AgfL
NE
Acceptable
Acceptable
Acceptable
Antimony
1
Acceptable
Acceptable
Acceptable
Arsenic
L
10
Acceptable
Acceptable
Acceptable
Barium,
1191L
700
Acceptable
Acceptable
Acceptable
Not evaluated because the values are below the groundwater standards or no standard is established.
Beryllium,
L
4
Acceptable
Acceptable
Acceptable
Bicarbonate
mg/L
NE
Acceptable
Acceptable
Acceptable
Boron
L
700
2
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acc table
Acceptable
Acceptable
Cadmium
L
Calcium
m L
3.60 lit 10.3 _
%I) _ tiD _ _ 5
IS 20.9 i
1.75 _ 11411_ t 033
4.72 _ _• 3.?_ 5 3
I 0,511s 1,6 0.76
Carbonate
Chloride
Chromium (VI)
L
mg/L
L
NE
Acceptable
Acceptable -
Acceptable
250
Acceptable
Acceptable
Acceptable
NA
Acceptable
Acceptable
Acceptable
Chromium
10
Acceptable
Acceptable
Acceptable
Cobalt
URIL
1
Acceptable
Acceptable
Acceptable
copper
1191L
2.7 5
9.7
1000
Acceptable
Acceptable
Acceptable
Not evaluated because the values are below the g2undwater standards or no standard is established.
Iron
L
750 240
228
300
Acceptable
I Acceptable
Acceptable
Lead
Magnesium
L
mg/L
1 I
3.41 6.94
0.11
3.35
15
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Not evaluated because the values are below the groundwater standards or no standard is established.
Manganese
µ
27.9 55
9.9
50
Acceptable
Not Acceptable
Acceptable
Dee should be 13 (or 2L) because of five ideatified omlitts.
Mere
L
_
ND ND
0.2
1
Acceptable
Acceptable
Acceptable
Methane
Mol bdeaum
991L
L
2.65 _ _ _2.64
1 -t- 1.3
4.26 4.67 _
3.6? 4.19
5 5 _
%D
(0
3.7
NE
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Not evaluated because the values are below the groundwater standards or no standard is established.
Nickel
µ
3.2
100
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
Potassium
Selenium
mg-N/L
m
0.17
5.15
0.5
11.
NE
20
NE
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable
Sodium
mg/L
_ _ND
5?2 _ _ _ 1 (1.' - _ _ 12
56.5 r 68 5 I ItU_
1 j o35 26
Strontium
NE
Acceptable
Acceptable
Acceptable
Sulfate
mg/L
250
Acceptable
Acceptable
Acceptable
Sulfide
mg/L
NT r ND 0.1
NE
Acceptable
Acceptable
Acceptable
TDS
mg/L
_ 85 14_X _ 1 _ 133
2 _ -} 1)'1 _
_tiD NU +_ 10.2
1.89 1 45 41.82
500
Acceptable
Acceptable
Acceptable
Thallimn
µg'L_U
0.2
Acceptable
Acceptable
Acceptable
TOC
mg/L
NE
Acceptable
Acceptable
Acceptable
Vanadium
L
0.3
Not Acce table
Acceptable
Acceptable
Shallow should be 1.33 because 2.01 was identified as an outlier.
Zinc
L
_ _
10 I 16
1000
Acceptable
Acceptable
Acc table
Not evaluated because the values are below the groundwater standards or no standard is established.
Radium (Total)
pCi/L
_ _43.2_
8. �q- 1.I 0.466
NE
Acceptable
Acceptable
Acceptable
Uranium (Total)
L
OAnr� O.oU05 0.Ot815q
NE
Acc table
Acceptable
Acceptable
NA -Not Applicable
NO - Not Detected
NE - Not Established
mp/L - milligram per liter
pCBL - picocuries per liter
Radimn (Total) - Radium-226 and Radium-228 combined
-Th. 15A NCAC 02L Standard's 10 mg/L for Nitrate and I mg/L for Nitrite (added for a total of I mg/L)
S.U. - Standard Unit
TOC - Total Organic Carbon
TDS - Total Dissolved Solids
,,/mL -micrograms per milliliter
pg/L - micrograms per liter
Uranium (Total) - Uranium-233, Uramumd34, Uranium-236, and Uranium-238 combined

Belews Creek Steam Station - Soil Provisional Background Threshold Values
Parameter
Reporting
Units
Duke Icnerg}
Calculated
PIS I S.t
PSRG Protection
of Groundwater
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
4 3 5 8
NE
Acceptable
Aluminum
mg/kg
3125,
NE
Acceptable
Antimony
mg/kg
0.6
0.9
Acceptable
Arsenic
m
12.64
5.8
Acceptable
Barium
mgfkg
139
580
Acceptable
Beryllium
mg/kg
19.3
63
Acceptable
Boron
mgWlkg
_ _
45
Acceptable
Cadmium
m kg
_1
0.032
3
Acceptable
Calcium
mg/kg
450
NE
Acceptable
Chloride
mg/kg
_
14
NE
Acceptable
Chromium
mg/kg
41.09
360000 (3.8)
Not Acceptable
Use the PSRG for Chromium (IV) of 3.8 mg/kg. PBTV for Chromium should be 36 mg/kg instead of 41.1 mg/kg because 43 was statistically
identified as outlier.
Cobalt
mg1kg
51.01
0.9
Acceptable
Copper
mg/kg
28.43
700
Acceptable
Iron
mg/kg
40400
150
Acceptable
Lead
mg/kg
39.72
270
Acceptable
Magnesium
mg/kg
3600
NE
Acceptable
Manganese
mglkg
Ill'
65
Acceptable
Mercury
mg/kg
0.1
1
Acceptable
Molybdenum
mg/kg
9.8
NE
Acceptable
Nickel
m
1 L6
130
Acceptable
Nitrate as N
mg/kg
0.3
NE
Acceptable
Potassium
mglkg
2114
NE
Acceptable
Selenium
mgfkg
5.431
2.1
Acceptable
Sodium
to g
191
NE
Acceptable
Strontium
mg/kg
9
NE
Acceptable
Sulfate
mg/kg
12
250
Acceptable
Thallium
mg/kg
0.852
0.28
Not Acceptable
PBTV for Thallium should be 0.69 mg/kg instead of 0.85. Please recalculate to verify your result
Vanadium
mg/kg
12t,
6
Not Acceptable
PBTV for Vanadium should be 114 m instead of 127 because, in addition to 280, 141 was also statistically identified as an outlier.
Zinc
mg/kg
51.'r.
1200
1 Acceptable
NA - Not applicable (dataset contains zero valid samples)
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit

NC; -
Water Resources
Environmental Quality
April 26, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: 2017 Comprehensive Site Assessment Update Comments
Belews Creek Steam Station
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
On October 31, 2017, the North Carolina Department of Environmental Quality's (DEQ's) Division of
Water Resources (DWR) received the 2017 Comprehensive Site Assessment (CSA) Update report for the
subject facility. Based on the review conducted to date, DWR has concluded that the sufficient information
has been provided in the report to allow preparation of the Corrective Action Plan (CAP); however, there
are deficiencies that must be addressed prior to or in conjunction with preparation of an approvable
Corrective Action Plan (CAP).
As described in the attached itemized list of CSA Update Report 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, landfills, ash storage
areas, ash stacks, structural fills, coal piles, and contaminated soils) must be included in the CAP's by
August 31, 2018, 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 a letter dated December 5, 2017, Duke Energy proposed a CAP submittal date of May 31, 2018.
However, due to the additional requirements stated above, and the time it took the DEQ to generate
comments, the updated CAP for the Belews Creek facility will be due on August 31, 2018.
An overview of CSA Update report deficiencies includes the following:
• The report contents are presented in a data summary format, exhibiting a lack of conclusive data
analysis and interpretation of site conditions.
• This report fails to fully integrate and evaluate data collected from previous versions of the CSA
reports for the facility.
• The distribution of constituents of interest related to coal ash sources presented in the report often
fail, for at least some areas of the site, to fully and clearly acknowledge and delineate exceedances
of the 15A NCAC 2L or 2B standards above background levels.
--'Nothtng Compares
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 characterization of other primary and secondary sources other than impoundments that
contribute to the groundwater plumes is inadequate, particularly near the chemical pond.
• As detailed more fully in the attached document, additional data gaps remain concerning
delineation of impacts from coal ash at the facility.
The deficiencies 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
DEQ believes should be collected to support proposed corrective action, may result in the DEQ approving
corrective action measures that comply with the rules, but may not be the most cost-effective. For example,
monitored natural attenuation cannot be approved for source areas where no surface water samples have
been collected (but could be collected) that demonstrate the groundwater discharge does not result in
exceedances of 15A NCAC 2B .0200 regulatory standards.
The evaluation of preliminary background threshold values developed for the facility as part of the 2017
CSA Update report will be provided to Duke Energy as part of a separate correspondence.
The DEQ would like to schedule a meeting between upper level management from DEQ and Duke Energy,
including select technical staff, to discuss the more significant deficiencies associated with the CSA
submitted October 31, 2017. We will reach out to Duke in the next several days to schedule the meeting at
the earliest possible time. Duke Energy should contact the Winston-Salem Regional Office to initiate the
scheduling of additional meetings between DWR and Duke Energy's technical staff (including contractors)
to discuss deficiencies 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]. Please contact Shuying Wang
(Winston-Salem Regional Office) at [phone] to discuss the CSA Update report deficiencies and
data gaps in more detail.
Sincerely,
S. Jay Zimmerman, P.G.
Division of Water Resources
Attachments: Attachment 1 Belews Creek Steam Station CSA Update Report Comments
cc: WSRO WQROS Regional Office Supervisor
WQROS Central File Copy

Comments for Belews Creek Steam Station Comprehensive Site Assessment Update
Submitted October 31, 2017
Groundwater Incident No.: 88227
Delineation of Groundwater Contamination
Questions remain concerning the accuracy of the delineation of horizontal and vertical extent of
groundwater contamination, which is a requirement of Coal Ash Management Act (CAMA) and
15A NCAC 02L .0106. The CAP shall include updated maps and data summary that address the
following:
■ The plume morphology of some constituents (beryllium, boron, and selenium in the
shallow zone, iron and vanadium in the deep zone, and thallium in both the shallow and
deep zones) are irregular and exhibit variable ranges of concentrations in the northwestern
area, which implies complex hydrogeological and geochemical conditions exist at this
portion of the site. This complexity with respect to contaminant distribution suggests that
more appropriately located downgradient well(s) are necessary to confirm site conditions
although coal combustion residuals (CCR) data does show that boron in GWA-19 is
sourced by the ash basin. For the same reason, it appears necessary to install a well(s)
downgradient from GWA-21 S to further delineate beryllium and thallium plumes. If
groundwater flow and fate/transport models do not indicate that the plumes will be
migrating off the property or causing any 02B violations, the installation of the additional
wells further downgradient may not be urgent or may not have to be done before the CAP,
but will have to eventually be installed for performance monitoring.
• High levels of boron have been consistently measured in MW-2-7 (22,700 µg/L, April 11,
2017) at Pine Hall Landfill. To determine the vertical extent, at least one additional
bedrock well appears to be needed. This was not requested earlier because the data from
the North Carolina Department of Environmental Quality (DEQ), Division of Waste
Management (DWM) was expected as this part assessment. If no additional deep or
bedrock well data from DWM can be provided, at least one deep or bedrock well is needed.
• In addition, boron was detected in CCR-6D at a concentration as high as 12,400 µg/L,
which also indicates that the vertical extent should be further delineated. A paired bedrock
well nest should be installed.
• With regards to porewater analysis, interpretations of site conditions that include analytical
results from specific sample locations (well IDs) are needed to justify the broad statement
regarding the decrease in concentrations. As the ash basin is an active basin, the cause for
decreasing concentrations in porewater should be evaluated, including implications for
constituent of interest (COI) concentration distribution and mobility.
• Provide an interpretation as to how the geochemical conditions affect or control the
distribution of COIs with site specific data (COI concentrations vs geochemical parameter
levels, identified with well IDs).
• Whether 11,200 µg/L of boron at GSA-20SA (Fig. 10-17) would drop to 852 µg/L at
GWA-11 S, and 184 µg/L at GWA-21 S through dilution alone should be discussed.
Whether the well positions or screened intervals of GWA-11 S and GWA-21 S are
measuring the flow path away from the hot spot should be discussed.
• High boron concentrations were detected in deep wells (e. g., 9,890 µg/L at GWA-20D and
5,420 µg/L at GWA-27D), but no 02L exceedances were measured in their paired bedrock
Page 1 of 4

wells. Whether these results are supported by site hydrogeologic conditions, such as
vertical hydraulic gradient and conductivity, should be discussed.
• For each water supply well that exhibits concentrations of constituents exceeding
02L/IMACs or preliminary background threshold values (PBTVs), whichever are higher,
provide an evaluation concerning potential receptors based on actual site data including
piper -diagrams, co-occurring constituents, proximity to CCRs, topographic setting,
geology, and dissolved oxygen, pH, etc.
• Provide an explanation why radium is not considered a COI.
• The pH values observed in GWA-19BR, GWA-20BR, and especially GWA-2713R, (the
most downgradient bedrock well in the northwest area) are consistently high likely due to
improper well construction. Whether these wells should be replaced needs to be discussed.
Other Potential Primm and Seconds Sources
As discussed previously, other primary and secondary sources must be assessed regarding impacts
to groundwater. Sources contributing to groundwater contamination associated with the
impoundments (commingled) must be assessed and the results incorporated into the CAP. Sources
that have impacted, or have the potential to impact groundwater (contaminated soils, stockpiles,
etc.) that are not known or believed to have commingled with the areas impacted by the
impoundment may be assessed separately in accordance with a schedule approved by the
Department. Additional information needed includes, but is not limited to, the following:
• Soil contamination should be delineated to either the site -specific preliminary background
concentrations (PBTVs) or Protection of Groundwater (POG) Preliminary Soil
Remediation Goals (PSRGs)levels, whichever are higher. If appropriate, use the equation
provided in the PSRG table to establish a POG PSRG for a constituent with 02L standard
that does not have one.
• Provide plan view maps and cross -sections (where applicable) to demonstrate that soil
contamination (POGPSRGs or PBTVs, whichever are higher) has been vertically and
horizontally delineated.
• Provide additional assessment concerning the comingling of plumes from the onsite
Structural Fill with the ash basin. To determine whether the contaminated groundwater
from the Structural Fill contributes to the plume resulted from the ash basin, at least, an
additional monitoring well between GWA-8S and the Structural Fill, but at the northern
side of Pine Hall Road, should be installed. The result will help determine whether the
source of boron in GWA-8S is from the ash basin or the structural fill. Sampling results
from SFMW-1D and SFMW-2D and bedrock well (expected from DWM) are also needed
to determine the vertical extent of the plume from the Structural Fill.
• Whether additional sediment assessment is needed at S-6, S-10, S-11, BCSW-007, BCSW-
008, and BCSW-19 area should be discussed.
• Please provide a description of the Chemical Pond in terms of its content, history, and
function relative to the NPDES permit.
• Provide an explanation of how and why soil contamination occurs outside of any waste
boundaries and more detailed discussion or evidence as to the reason for the elevated
concentrations of chromium, iron, strontium and vanadium in soils upgradient of the ash
basin (GWA-6S, GWA-7S and GWA-813).
Page 2 of 4

Maps, Figures, and Tables
Additional tables, maps and figures are necessary to better represent an understanding by Duke
concerning the horizontal and vertical extent of soil and groundwater impacts, associated risks to
receptors, secondary source impacts, etc. These include but are not limited to:
• Isoconcentration maps: If a well was sampled, even when pH was elevated, the data should
be used to plot isoconcentration maps with footnotes that explain that better quality data
are needed to provide a more accurate assessment of site conditions. In addition, as a
certain number of wells were not sampled in April 2017, the isoconcentration maps may
not represent true site conditions (plume shape and size). Therefore, all isoconcentration
maps should be updated with a complete sampling event including all wells, (including
CCR wells, if appropriate) and present the updated maps in the CAP. Otherwise, if the
maps could not be updated with adequate data, please provide isoconcentration maps for
each sampling event for boron. Furthermore, assumptions made concerning r how
groundwater plumes are depicted without a monitoring well in the middle of the ash basin
or the landfill should be provided. For examples figures 10-44, 10-54, etc.
• Figure 2-10 should be updated to include all CCR well locations.
• Additional comments regarding figures and tables can be discussed in detail between
WSRO and Duke Energy staff prior to completing the CAP.
02L/02B Surface Water Samplinx
Collection of surface water samples to evaluate impacts from contaminated groundwater is
necessary to understand the impacts associated with the migration of contaminants from the
groundwater system. Failure to adequately characterize known and potential impacts to surface
waters from groundwater will affect the corrective action strategies that can be proposed and
ultimately considered for approval by the Department. Comments include, but are not limited to,
the following:
• Additional surface water sampling along the east bank of Belews Reservoir was discussed
in May 18, 2017 meeting between Duke and DEQ. A sampling proposal was submitted by
Duke through an email on October 4, 2017 and agreed to by the division staff, however,
the proposed sampling was not performed. The additional agreed upon surface water
assessment must be completed and included in the CAP. All samples must be collected in
accordance with DEQ's Internal Technical Guidance: Evaluating Impacts to Surface
Water from Discharging Groundwater Plumes.
• For any sample results deemed invalid, state what caused the sample to be invalid, the
rationale for not including the data, and any proposed remedies such as plans for
resampling. (Refer to Section 9.1).
Groundwater Flow Contaminant Flow, and Trans ort
Additional information related to groundwater flow and the mechanisms affecting contaminant
migration is necessary, including but not limited to, the following:
• Provide a rationale or evidence that suggests that underground utilities will not serve as
preferential conduits for contaminant movement.
Page 3 of 4

• Section 6.5 states: "Hydraulic conductivity values for wells screened in saprolite have a
geometric mean of 2.65 x 10-4 cm/sec. Hydraulic conductivity values for wells screened in
the transition zone have a geometric mean of 7.91 x 10-5 cm/sec. 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. " To justify
this statement, please provide evidence showing the transition zone has higher clay content
and other weathering by-product than the shallow aquifer at this site as hydraulic
conductivity is lower in the transition zone than in the shallow aquifer.
• Provide an explanation or documentation concerning the statement (Section 6.6) that
bedrock fractures tend to be isolated with low interconnectivity and the primary porosity
is considered negligible, and correlate the statement to horizontal and vertical migrations
of COIs in the bedrock.
Mo— delin-
Additional information needed includes the following:
• Both groundwater and geochemical models must be updated and included in the revised
CAP due August 31, 2018.
• All COIs should be modeled unless a rationale for not doing so is provided.
• In Section 3.3, implications for leachability and downgradient mobility of contaminants
from the source area should be discussed, as well as, implications for transport model
source inputs and for transport and risk should be discussed.
• In Section 4.4, it should be discussed whether the effects of pumping from the private water
supply wells were accounted for in the model with regards to particle tracking.
• Groundwater divides that have been identified at Pine Hall Road and Middleton Loop Road
(Section 6.3) should be reconsidered, because existing information confirms groundwater
beneath the ash basin flows across Middleton Loop Road towards northwest. Whether there
is uncertainty with respect to the position of groundwater divides for modeling particle
tracks or transport should also be discussed.
Risk
• The updated status of alternative water supply for supply wells within 0.5 miles of the BC
indicates that 52 households are eligible, 41 selected water filtration systems, 6 opted out
of selections of water line and water filtration system (refused both), and 5 did not respond.
Please list names and addresses of these 11 households and identify these property on the
map. In addition, please also list the name and address for each vacant lot within 1500 feet
of CB and show them on the map.
• Each of the constituents of concern identified in CAP Part 2 report that exceed their
respective risk target should be discussed.
Page 4 of 4

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
Belews Creek 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 (October 2017), 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: h"s://deq.nc.Rov/about/divisions/waste-management/superfund-section/inactive-
hazardous-sites-program.
­ . ->- othing Compares
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 Shuying Wang (Winston-Salem Regional Office) at (336)
776-9800 or Steve Lanter (Central Office) at [phone].
Sincerely,
LinlV �
a Culpepper, Director
Division of Water Resources
Attachments
cc: WSRO WQROS Regional Office Supervisor
WQROS Central File Copy

Belews Creek Steam Station - Groundwater Background Threshold Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy Calculated PBTVs from CSA
Report (October 31 2017)
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.
5.1-6.03
5.19-7.02
6.3-6.5
6.5-8.5
Acceptable table
Acceptable
Acotptable
Alkalinity
mg/L
22.9
63.7
81.3
NE
Acceptable
Acceptable
Acceptable
Aluminum
tg/L
860
140
100
NE
Acceptable
Acceptable
Acceptable
Antimum
peg/L
1
1
0.5
1
Acceptable
Acceptable
Acceptable
Arsenic
µg/L
1
1
0.51
10
Acceptable
Acceptable
Acceptable
Barium
ig/L
58
12.6
6.2
700
Acceptable
Acceptable
Acceptable
Bcrvllium
p
0362
0.219
0.2
4
Acceptable
Acceptable
Acceptable
Bicarbonate
mg/L
22.3
62.9
77.6
NE
Acceptable
Acceptable
Acceptable
Boron
µ
50
50
50
700
Acceptable
Acccptable
Acceptable
Cadmium
Eg/L
1
1
0.08
2
Acceptable
Acceptable
Acceptable
Calcium
mg
3.69
13.2
103
NE
Acceptable
Acceptable
Acceptable
Carbonate
m
5
5
5
NE
Acceptable
Acceptable
Acceptable
Chloride
mg/L
15
20.9
3
250
Acceptable
Acceptable
Acceptable
Chromium (VI)
µ
1.75
0.411
033
NA
Acceptable
Acceptable
Acceptable
Chromium
µg/L
4.72
33
53
10
Acceptable
Acceptable
Cobalt
µg/L
0.509
1.6
0.76
1
-Acceptable
Acceptable
Acceptable
Acceptable
Copper
/L
2.7
5
9.7
1000
Acceptable
Acceptable
Acceptable
Iron
µg/L
750
240
228
300
Acceptable
Acceptable
Acceptable
Lead
1
1
0.11
15
Acceptable
Acceptable
Acceptable
Magnesium
m
3.41
6.94
3.35
NE
Acceptable
Acceptable
Acceptable
Manganese
vg/L,
22.9
13
9.9
50
Acceptable
Acceptable
Acceptable
Mercury
OWL
0.2
0.2
0.2
1
Acceptable
Acceptable
Acceptable
Methane
11911L
2.65
2.64
10
NE
Acceptable
Acceptable
Acceptable
Molybdenum
µg/L
1
1.3
3.7
NE
Acceptable
Acceptable
Acceptable
Nickel
pg/L
4.26
4.67
3.2 1
100
Acceptable
Acceptable
Acceptable
Nitrate + Nitrite
mg-N/L
3.63
4.19
0.17
l l *
Acceptable
Acceptable
Acc . table
Potassium
mg/L
5
5
5.15
NE
Acceptable
Acceptable
Acceptable
Selenium
µg/L
0.5
0.5
0.5
20
Acceptable
Acceptable
Acceptable
Sodium
m
5.92
10.7
12
NE
Acceptable
Acceptable
Acceptable
Strontium
g/L
56.5
68.5
100
NE
Acceptable
Acceptable
Acceptable
Sulfate
mg/L
1.93
6.35
9.6
250
Acceptable
Acceptable
Acceptable
Sulfide
mg
0.1
0.1
0.1
NE
Acceptable
Acceptable
Acceptable
TDS
m
85
148
133
500
Acceptable
Acceptable
Acceptable
Thallium
µ
0.2
0.2
0.1
0.2
Acceptable
Acceptable
Acceptable
TOC
m
1
1
10.2
NE
Acceptable
Accrl,table
Acceptable
Vanadium
WL
133
1.45
0.82
0.3
Acceptable
Acceptable
Acceptable
Zinc
P CIL
10
43.2
16
1000
Acceptable
Acceptable
Acceptable
Radium (Total)
Ci/L
8.74
1.1
0.466
NE
Acceptable
Acceptable
Acceptable
Uranium (Total)
ji !•/L
1 0.0005
0.0005
0.00054
NE
Acceptable I
AcctTptable
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 1 mg/L for Nitrite (added for a total of I 1 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

Belews Creek Steam Station - Soil Background Threshold Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy
Calculated PBTVs
from CSA Report
(October 31, 2017)
PSRG Protection of
Groundwater (as of
February 2018)
DWR Concurrence
(Acceptable/Not
Acceptable)
Comments
H
S.U.
4.3 - 5.8
NA
Acceptable
Aluminum
-v-lkm
31253
110000
Acceptable
Antimony
mglkg
0.6
0.9
Acceptable
Arsenic
mglkg
12.6
5.8
Acceptable
Barium
mgikg
139
580
Acceptable
Beryllium
mWkg
19.3
63
Acceptable
Boron
mWkg
17
45
Acceptable
Cadmium
mgfkg
0.032
3
Acceptable
Calcium
mgIg
450
NE
Acceptable
Cbloride
m ' g
14
NE*
Acceptable
Chromium i total i
mg/kgmg/kg
36
3.8
Acceptable
Cobalt
mWkg
51
0.9
Acceptable
Co , er
mglkg
28.4
700
Acceptable
Iron
mWkg
40400
150
Acceptable
Lead
MgAg
39.7
270
Acceptable
Magnesium
rngAg
3600
NE
Acceptable
Manganese
mg/kgmg/kg
1117
65
Acceptable
Mercun
rnog
0.1
1
Acceptable
Molybdenum
MWKg
9.8
7.1
Acceptable
Nickel
m kg
11.6
130
Acceptable
Nitrate (as N 1
mgAg
0.3
NE
Acceptable
Potassium
mWkg
2114
NE
Acceptable
Selenium
m kg
5.44
2.1
Acceptable
Sodium
mglkg
393
NE
Acceptable
Strontium
mg/kgmg/kg
9
NE
Acceptable
Sulfate
mg/kgmg/kg
12
NE*
Acceptable
Thallium
rng/kg
0.69
0.28
Acceptable
Vanadium
I MWkg
114
350
Acccptable
Zinc
I m kg
51.8
1 200
Acceptable
*Constituent has 2L Standard or MAC. Use calculation in the PSRG table to determine value.
NA - Not applicable
ND - Non -Detect
NE - Not Established
mglkg - milligrams per kilogram
S.U. - Standard Unit

From: Smith, Eric G[mailto:eric.g.smith(a)ncdenr.gov]
Sent: Wednesday, May 23, 2018 12:07 PM
To: Toepfer, John R; Sullivan, Ed M
Cc: Zimmerman, Jay; Wang, Shuying; Knight, Sherri; Risgaard, Jon; Lanter, Steven
Subject: Duke Coal: Belews Creek Full Draft Comments for Discussion Friday
*** Exercise caution. This is an EXTERNAL email. DO
NOT open attachments or click links from unknown
senders or unexpected email. ***
John & Ed:
As promised, attached are the full set of comments prepared by WSRO on the Belews Creek Steam
Station Updated CSA Report. These comments will serve as basis for discussion during this Friday's
technical meeting at the Winston-Salem Regional Office.
-Eric G. Smith
Eric G. Smith
Program Consultant
Division of Water Resources
Water Quality Regional Operations Section
Animal Feeding Operations & Groundwater Protection Branch
Department of Environmental Quality
919 807 6407 office
eric.g.sm ith(c_ncdenr.gov
512 N. Salisbury St
1636 Mail Service Center
Raleigh, NC 27699-1636
NI - C-.
-:5>"Nlothing Compares
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.

ROY COOPER
Governor
HCHAEL 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 Coal Combustion Residuals Surface Impoundment
located at Duke Energy's Belews Creek Steam Station, Stokes 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 coal
combustion residuals surface impoundment, called the Active Ash Basin, located at Duke
Energy's Belews Creek Steam Station in Stokes County, NC. NCDEQ makes the following
specific findings:
1. Duke Energy has established permanent water supplies as required for the above
referenced impoundment pursuant to N.C. Gen. Stat § 130A-309.21l(cl). See Exhibit 1
(Duke Energy Alternate Water Supply Submittal) and Exhibit 2 (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 impoundment pursuant to N.C. Gen. Stat. § 143-
215.32. Specifically, the above referenced impoundment at Duke Energy's Belews Creek
Steam Station was not subject to Dam Safety Order 16-01 (issued on August 22, 2016)
and was inspected by NCDEQ with no deficiencies noted. See Exhibit 3 (Dam Safety
Order 16-01), Exhibit 4 (Dam Inspection Report), Exhibit 5 (October 3, 2018 DEMLR
Letter Regarding Dam Safety Order 16-01 Compliance Status), and Exhibit 6 (October
10, 2018 EMC Meeting Minutes).
0-E
North Carolina Department of Environmental Quality
217 West Jones Street 11601 Mail Service Center I Raleigh. North Carolina 27699-1601
919.707.8600

Based upon the determinations above and in accordance with the Coal Ash Management Act,
NCDEQ classifies the coal combustion residuals surface impoundment, called the Active Ash
Basin, at Duke Energy's Belews Creek Steam Station as low -risk.
If you have any questions about NCDEQ's determinations provided in this letter, please contact
me at [phone].
Sincerely,
C. ))�
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
North Carolina Department of Environmental Quality
217 West ]ones Street 1 1601 Mail Service Center I Raleigh, North Carolina 27699-1601
919.707.8600

North Carolina Department of Environmental Quality's (NCDEQ's) Review Position concerning:
Attachment 2
Supporting Rationale for Proposed Interpretation and Adjustments to the
Corrective Action Plan Content Guidance (NCDEQ April 2018) by
Duke Energy January 2019
CAP Guidance
Duke Energy's
DEQ's Position regarding
Section*
Rationale for Proposed Adjustments
Duke Energy's Proposed
Adjustments
Executive Summary
• Added Executive Summary to provide a
Acceptable.
high-level summary of the Corrective Action
Plan's (CAP) conceptual site model (CSM)
and the site -specific corrective action
approach proposed based on the CSM.
1. INTRODUCTION
1.C.b.
• Deleted text referring to the Notice of
Deleting text concerning the
Regulatory Requirements (NORR). These
NORR in the section is not
NORR requirements are focused on the
acceptable and related content
Comprehensive Site Assessments (CSAs) and
must be reflected in the CAP.
are not directly relevant to the CAP.
The information in the NORR
required by rule was not
provided in a complete manner
in the CSA documents;
whereas, the information in
the letters generated by the
Regional Offices identified
what is needed. This
information was not provided
in previous submittals and shall
be included in the CAPS.
1.D
• Added text to clarify that the CAP will
The proposed additional text is
provide a general written description of how
acceptable; however, the
these items were considered during the CAP
criteria that will be used for
preparation process per 02L .0106(i). This is
evaluation and selection of
also intended to clarify that the criteria
remedial alternatives in the
provided in Section 7.D.a.iv.1-10 will be used
CAPS should be provided in
for evaluation and selection of remedial
Section 6.
alternatives in the CAPS.
July 29, 2019

Page 2 of 11
CAP Guidance
Duke Energy's
DEQ's Position regarding
Section*
Rationale for Proposed Adjustments
Duke Energy's Proposed
Adjustments
1.E.b.
• Added text to clarify that only non -coal
Acceptable. Acknowledge and
waste streams that may affect the
identify other primary and
subsurface conditions at or proximate to
secondary sources present that
coal ash basins or coincident source areas
are not under the jurisdiction
will be included to maintain focus on the
of CAMA. Provide DEQ Division
Coal Ash Management Act requirements.
oversight and Incident Number
if relevant.
2. RESPONSE TO COMPREHENSIVE SITE ASSESSMENT UPDATE COMMENTS IN SUPPORT OF CAP
DEVELOPMENT
2. and 2.13.
• The note at the top of the section clarifies
Acceptable. Revised
how responses to the NCDEQ CSA comment
interpretations of site
letters will be addressed in the CAP to
conditions that address
facilitate the NCDEQ's review. Modification
Department concerns
to the text in Section 2.13.a.&b. has been
identified in the CSA comment
revised to reflect this approach.
letters shall be provided in the
documents to support
determination of appropriate
remedial alternatives.
3. OVERVIEW OF SOURCE AREAS BEING PROPOSED FOR CORRECTIVE ACTION
Added a note that describes the role of ash
Acceptable.
basin decanting and ash basin closure plans
as source removal/control methods that are
linked to the groundwater corrective action
plan for each site. Duke Energy will add a
discussion of the source control measures
(the approved Closure Plan) and the benefits
to groundwater restoration and integration
into the corrective action program.
3.A.
• Added reference to the NCDEQ letter
Acceptable.
providing the list of sources for each site to
be addressed in CAP.
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 3 of 11
CAP Guidance
Duke Energy's
DEQ's Position regarding
Section*
Rationale for Proposed Adjustments
Duke Energy's Proposed
Adjustments
3.B.
• Revised text to reference NCDEQ letter
Acceptable.
providing list of sources for each site that
will be addressed in subsequent and
separate CSAs.
• Previously numbered items a, b, c are no
longer needed due to the clarification
provided by the NCDEQ's letter and were
deleted.
4. SUMMARY OF
BACKGROUND DETERMINATIONS
4.B.
• Added text to provide discussion of
Acceptable. However, site -
regional background concentrations for
specific background data
similar geologic settings as context for soil
collected proximal to the
background Threshold Values (BTVs).
subject facilities are the basis
for corrective action decisions.
4.C.
• Added text to provide discussion of
Acceptable. However, site -
regional background concentrations for
specific background data
similar geologic settings as context for
collected proximal to the
groundwater BTVs.
subject facilities are the basis
for corrective action decisions
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 4 of 11
CAP Guidance
Section*
Duke Energy's
Rationale for Proposed Adjustments
DEQ's Position regarding
Duke Energy's Proposed
Adjustments
4.D.
• Revised text to indicate that referenced
This proposed change is not
EPA values are recommended "criteria". EPA
acceptable since application of
Nationally Recommended Water Quality
EPA NRWQC by DEQ is
Criteria for Aquatic Life & Human Health
authorized in the context of
(EPA NRWQC) have not been universally
using narrative regulations for
adopted under 15A NCAC 02B. Sample
toxic controls where no surface
results will be compared to those criteria
water quality standard has
found in 15A NCAC 02B .0211(11) with
been adopted into state
values for EPA NRWQC provided for
regulations. This is consistent
reference.
with state authority under
Clean Water Act directives as
well as state administrative
code with respect to corrective
action.
Stream segments near samples
that exhibit exceedances or
that demonstrate impacts
attributable to coal ash should
be evaluated for potential
groundwater/ surface water
discharge and appropriate
remedial measures shall be
considered for corrective
action.
Direction concerning
evaluation of 15A NCAC 2B
standards was provided in an
email from Eric Smith to John
Toepfer on July 19, 2018. The
process for evaluating state
water quality standards,
criteria, and protective values
should be followed as
described in the website
regarding 15A NCAC 02B
surface water standards:
https://deg.nc.gov/nc-
stdstable-09222017
DEQ will work with Duke
Energy to determine the
appropriate response to
exceedances of the 15A NCAC
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 5 of 11
CAP Guidance
Duke Energy's
DEQ's Position regarding
Section*
Rationale for Proposed Adjustments
Duke Energy's Proposed
Adjustments
02B surface water quality
standards where applicable.
Removed Section - SUMMARY OF POTENTIAL RECEPTORS
• Removed this section and consolidated
Acceptable. Note that since the
potential receptor information into Section
hydraulics and
6.13. This will avoid presenting redundant
groundwater/surface water
information.
flow patterns near the ash
basins have changed over the
years, all areas that may have
been impacted should be
considered with respect to
potential receptors.
5. CONCEPTUAL SITE MODEL (CSM) — New Section
• Placed CSM into a more prominent
Acceptable. A figure that
position in the guidance document to
illustrates groundwater
emphasize the importance of the CSM to
impacts with a 3-dimensional
support corrective action decision -making.
perspective should be included
All elements from Section 6.A.b.i. were
as part of the revised CSM.
included along with additional items to
make the CSM more robust.
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 6 of 11
6. SOURCE AREA 1
6. Opening Section
• Paragraph 1 - Deleted text referring to
Overall, the proposed changes
Paragraphs
discussions with regional DWR office to
to the text are acceptable.
identify source areas. This item was resolved
However, observations
by NCDEQ letter identifying source areas.
concerning proposed changes
These sources will be considered for
to specific paragraphs include:
corrective action based on the results of the
site assessments currently in progress.
Concerning proposed text
revision in Paragraph 3, note
• Paragraph 3- Edited text to identify water
that since the hydraulics and
supply wells and surface water features
groundwater/surface water
hydraulically downgradient relevant to
flow patterns near the ash
Source Area 1 to focus only on those areas
basins have changed over the
that could potentially be affected to
years, all areas that may have
facilitate the corrective action
been impacted should be
preparation process. The CAP will provide
considered with respect to
justification for selection of water supply
potential receptors.
wells and downgradient surface water
features relevant to each source area.
Concerning proposed text
revisions in Paragraph 4, while
• Paragraph 4 - Added text to define
the definition of COI presented
constituents of Interest (COls) for corrective
is consistent with15 NCAC 02L.
action. This is consistent with 15 NCAC 02L.
0106(e)(4) corrective action
0106(e)(4) corrective action requirements to
requirements, any constituent
address constituents with concentrations
identified by the Department
greater than 2L applicable values at or
that has migrated across, or
beyond the compliance boundary. This
has potential to migrate across,
approach will focus the information
the compliance boundary shall
presented and the corrective action to the
be considered as part of any
constituents exceeding the applicable
remedial design. This concept
standard (2L/IMAC/BTV) at the relevant
shall be reflected in the CAPS.
point of compliance.
Refer to requirements related
to 2L .0107(k).
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 7 of 11
6.A.a
• Added text to reduce representing data
Not acceptable. This proposed
previously provided to NCDEQ with the
change is problematic since a
intent of leaving more time to focus on
complete and defensible data
corrective action analysis.
set was not provided in the
past. Sufficient data must be
included to justify any
proposed corrective action.
Duke may not rely on
previously submitted data to
justify such proposed
corrective action. Additionally,
consensus concerning which
Cols to analyze for corrective
action must be reached
between Duke Energy and the
respective Regional Offices.
The data needed to address
NCDEQ CSA Update comments
shall be provided in the body of
the CAP. In summary, the
Department does not believe
that all data have been
provided in a comprehensive
manner at this time to
adequately evaluate site
conditions and refine remedial
design to facilitate decision
making regarding corrective
action. Also, providing data or
responses to CSA Update
comments only in an appendix
is not acceptable.
6.A.a.v
• Revised text to remove the reference to
Acceptable.
the calculation of specific storage. Specific
storage is a general aquifer parameter that
represents the amount of groundwater per
unit volume of a saturated formation that is
lost or gained from storage due to the
compressibility of the mineral framework
that comprises the formation and the pore
water per unit change in head rather than
being used to evaluate COls in groundwater.
The groundwater flow and transport model
will estimate the COI concentrations over
time for the evaluation of remedial
alternatives. This approach provides a more
meaningful representation of the
performance of the remedial alternatives
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 8 of 11
over time compared to a calculation of
specific storage.
6.A.a.vi.1.
• Added Ash Leachate Environmental
Acceptable.
Assessment Framework (LEAF) sample data.
6.A.a.vi.3
• Added text to allow for figure preparation
The overall concept of
flexibility such as the use of exceedance
flexibility with respect to figure
ratio maps and including the surrounding
generation for the CAPs is
area.
acceptable, but the specific
constituents that will be
mapped in the documents shall
be determined by consensus
with the DEQ Regional Offices.
The Department acknowledges
that the isolated and irregular
spatial distribution exhibited by
some constituents does not
translate well to the
conventional illustration of
groundwater plumes.
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 what is
needed to explain site
conditions and risk to the
public. Duke Energy should
initiate dialogue with the DEQ
Regional Offices to facilitate
agreements concerning
constituents that will be
mapped in the CAPs.
6.A.a.vii
• Revised text to indicate "other source
Acceptable.
material", if any, will be addressed based on
the results of the additional source area
assessments currently underway.
6.A.b.
• Added text to clarify that the discussion
Acceptable. The June 2019 cut -
regarding the extent of COls will include
off date for inclusion of data
data collected through June 2019. This will
into a CAP is acceptable for
provide Duke Energy with the needed time
sites where document
to reduce site data and include it in the
submittals are scheduled for
interpretation of site conditions.
December 2019. However,
CAPs due at later dates should
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 9 of 11
will have different data cut-off
dates based on Duke Energy's
internal review process.
6.A.b.i.1-6.
• Removed text to the newly created
Acceptable.
Section 5 above to place greater emphasis
on the CSM.
6.A.b.ii.
• Added text that COI results presented are
This proposed change is not
to be based on consideration of geometric
acceptable since any 2L
mean concentrations and/or time vs.
Standard exceedances
concentrations relationships based on
detected at a site are relevant
historical data collected through June 2019.
and should be acknowledged
This approach will provide more appropriate
and discussed. Discussions
concentration results for corrective action
concerning specific COls that
planning by eliminating anomalous or
will be considered for
inconsistent data likely associated with
corrective action will
transient geochemical variations.
commence on March 15, 2019.
See time -frame reference with
respect to data that shall be
incorporated into the
documents in response to
proposed 6.A.b. text changes.
6.A.b.iii.1.6.
• Eliminated table of analytical results for
Acceptable.
supply wells in this section since the same
information is requested in Section B.b.ii. to
eliminate redundant information.
6.A.c.i-ii.
• Removed this section since very similar
Not acceptable. Do not
information is requested in Section 6.D.a.i-ii
remove. Keep the section and
which is more focused on corrective action
provide a list of COls for each
analysis.
area that require corrective
action.
6.A.c.i-ii.
• Added to text to clarify that
Acceptable.
isoconcentration maps will be included for
COls identified for remediation.
6.A.e.
• Changed section title from Plume
Acceptable.
Characteristics to COI Distribution in
Groundwater to reflect the fact that not all
inorganic COls behave as a "plume" and are
often isolated and/or transient due to
geochemical conditions.
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 10 of 11
6.a.e.i.1.
• Revised text to say 'stable' to expanding'
Acceptable.
rather than 'moving' and (or) expanding
since 'moving' is very similar
to expanding. This wording is also consistent
with NCDEQ and USEPA MNA guidance
concerning the description of plume
behavior.
6.a.e.ii.1.
• Revised text to provide a general
Acceptable. Provide content
discussion of site geochemical conditions in
that was directed in the CSA
the body of the CAP recognizing
Update document comments.
that the detailed geochemical items listed
will be included in the geochemical
modeling report which will be presented
in the appendices.
6.B.a
• Revised text to clarify that only those
Acceptable. Note that since the
surface waters that are hydraulically
hydraulics and
downgradient that could be affected by
groundwater/surface water
site -related COls will be identified on the
flow patterns near the ash
map to maintain focus on those areas that
basins have changed over the
may need to be addressed under the CAP.
years, all areas that may have
been impacted should be
considered with respect to
potential receptors.
6.B.b.
• Revised to provide clarity regarding
Acceptable.
identification of water supply wells.
6.D.a.i.1.
• Removed text regarding a 3-dimensional
Acceptable.
(3-D) map. A 3-D block diagram figure will be
included as part of the CSM.
6.D.a.iii.
• Removed this section on predictive
Not acceptable. Keep this
modeling. Duke Energy proposes to
section and provide a succinct
consolidate this section into the
summary of modeling results.
groundwater modeling report that will be
presented as an appendix to the CAP. The
groundwater modeling will be used to
inform corrective action decision -making.
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

Page 11 of 11
6.E.b.
• Added text to indicate information
Acceptable. Provide enough
requested will be provided at conceptual
information and detail for the
design level.
various remedial alternatives
considered to facilitate review.
A higher level of cost detail
shall be provided for the
remedial alternative selected in
order than others considered
to provide adequate
information for decision
making. Otherwise, additional
documentation may be
required before an alternative
is approved.
6.E.b.iv.
• Added "approximate" to costs since
See comments above
information will be at conceptual level.
concerning Section 6.E.b.
10. MAPs AND FIGURES
• Added note that describes Duke Energy's
Acceptable. Isoconcentration
approach for figures to be included in the
maps shall provide mapping of
CAP with an emphasis on
analytical results to
making the CAP more manageable on a
background or non -detect
practical basis and focusing on those figures
levels to depict concentration
necessary to support our corrective action
gradients related to COI
approach.
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.
11. APPENDICES
Added a general planned list of CAP
Acceptable. Final content
appendices to clarify what will be included
should be based on a
in the CAP deliverables. The
consensus developed between
appendices may be adjusted on a site-
Duke Energy and the respective
specific basis as needed.
DEQ Regional Offices and
should include all supporting
documentation for remedial
alternative design.
*Refers to the proposed revised CAP guidance section and supporting rationale provided in
Attachment 2 of Duke Energy Interpretation of Corrective Plan Content Guidance Provided by the
North Carolina Department of Environmental Quality January 23, 2019
DEQ Position Duke Energy's Proposed CAP Guidance Revisions January 2019

rc IL IL, f r
tiffs£ QUAM
DEQ Coal Combustion Residuals
Surface Impoundment
Closure Determination
Belews Creek Steam Station
April 1, 2019
MEQ�1�
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DEQ Coal Combustion Residuals Surface Impoundment Closure Determination
Belews Creek Steam Station
Executive Summar
The Coal Ash Management Act (CAMA) establishes criteria for the closure of coal
combustion residuals (CCR) surface impoundments. The CCR surface impoundment located at
Duke Energy Carolinas, LLC's (Duke Energy) Belews Creek Steam Station (Belews Creek) in Stokes
County, NC has 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). 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 10, 2019 in Walnut Cove, NC
where the community near Belews Creek had the opportunity to learn about options for closing
coal ash 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 impoundment at the Belews Creek 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 Belews Creek 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
impoundment at Belews Creek by August 1, 2019. The Closure Plan must conform to this election
by DEQ.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 1

Intrnrli irtinn
DEQ has evaluated the closure options submitted by Duke Energy for the CCR surface
impoundment at the Belews Creek Steam Station. This document describes the CAMA
requirements for closure of coal ash impoundments, the DEQ evaluation process to make an
election under CAMA for the subject impoundment at the Belews Creek site, and the election by
DEQ for the final closure option.
II. Site History
Duke Energy owns and operates the Belews Creek Steam Station which is located on
Belews Lake Reservoir in Belews Creek, Stokes County, North Carolina. Belews Creek is a two -
unit 2,240-megawatts coal-fired generating facility that began commercial operation in 1974.
Prior to 1984, Belews Creek wet sluiced coal combustion residuals into one surface impoundment
located on the property. The surface impoundment is known as the Active Ash Basin (AAB) and
is impounded by dam STOKE-116.
In 1984, Belews Creek replaced its fly ash wet sluicing operation with a dry ash handling
system and began placing dry fly ash into one of three permitted landfills located on the property:
Pine Hall Road Landfill (8503-INDUS-1984, closed), Craig Road Landfill (8504-INUDS, active), and
FGD Landfill (8505-INUDS, active). However, the ability to wet sluice to the AAB was still available
but limited to certain situations: unit startup/shutdown, equipment maintenance, and service.
Currently, a 100% dry ash handling system is being used onsite and no CCR is being sluiced to the
AAB. A Flue Gas Desulfurization (FGD) scrubber system is active at Belews Creek where the FGD
residuals are beneficially reused for the production wallboard.
III. CAMA Closure Requirements
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).
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 2

Pursuant to N.C. Gen. Stat. § 130A-309.213(d)(1), DEQ has classified the CCR surface
impoundment at Belews Creek 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 B]; 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."
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 3

Table 1: CAMA Closure Options for Low -Risk CCR 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]
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 4

By referencing the closure options for high -risk 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. DEG Election Process
Beginning with a letter to Duke Energy on October 8, 2018, DEG began planning for a
thorough evaluation of the closure options for low -risk impoundments before making an election
as outlined in Table 1 above. DEG's objectives were to receive input on closure options from
Duke Energy and to engage with community members near low -risk sites. DEG 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 10, 2019 — DEG public meeting near Belews Creek
• April 1, 2019 — DEG 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 Belews Creek site that are either CCR impoundments or hydrologically
connected to CCR impoundments
DEG 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.
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 Belews Creek site has extensive amounts of data that
have been collected during the site assessment process, and these data were used as part of the
evaluation of closure options. DEG's evaluation of closure in place and hybrid option based on
groundwater monitoring and modeling data is provided in Attachment A. That analysis
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 5

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 Walnut Cove, NC near Belews Creek on January 10,
2019. Approximately 98 people attended the meeting. Approximately 1052 comments were
received during the comment period, which closed on February 15, 2019. Additionally, 275
people signed an attachment to written comments and an additional 340 people signed an on-
line petition. A sizeable minority of commenters specifically recommend excavating coal ash and
moving it to a lined onsite landfill. A small minority of commenters want the coal ash moved out
of state. No commenters support the hybrid closure or closure -in -place option. Several
commenters support recycling coal ash for various commercial product uses. 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
impoundment at the Belews Creek 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 at Belews Creek 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 impoundment at
Belews Creek 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 impoundment at Belews Creek.
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 Belews Creek.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 6

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 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 future modeled extent of the plume, DEQ does not believe these two closure options
can meet the requirements of CAMA Option B for the CCR surface impoundment at Belews Creek.
DEQ does not elect CAMA Option C (i.e., closure under the federal CCR Rules found in 40
CFR Part 257) for the CCR impoundments at Belews Creek. 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 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
impoundments across the country, CAMA was written specifically to address the CCR
impoundments in North Carolina.
e. While the federal CCR Rule allows CCR 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.
BELEWS CREEK 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 at
Belews Creek 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.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 8

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

The Contaminated Plume is Bevond the Compliance Bounda
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. Significantly, the contaminated groundwater plume has
already extended beyond the compliance boundary in a portion of the impoundment. The
inferred general extent of groundwater impacts above applicable Background Threshold Values
or 2L Standards are shown on Figure ES-1. Additional monitoring and hydrogeological data is
available in the Belews Creek Steam Station October 2017 CSA Update Report (available on the
DEQ website).
Based on review of data submitted to date in various reports, both soil and groundwater
have been impacted by CCR handling activities at the site. Groundwater within the area of the
impoundment generally flows north to northwest toward Dan River and south of a topographic
ridge that serves as a groundwater divide along Pine Hall Road toward Belews Lake Reservoir.
Boron concentrations above 2L Standards approximates the leading edge of the CCR plume at
the site. Almost all constituents of interest (COls) are present in the shallow flow layer. The
horizontal extent of those COls are generally within the footprint of the boron plume.
The vertical extent of most COls is within the shallow and transition flow layers. However,
data suggests the bedrock flow layer has been impacted by CCR handling activities at the site.
Manganese is the only COI with a significant exceedance of the 2L standard in the bedrock flow
layer.
DEQ concludes that the contaminated groundwater plume above 2L standards has
extended beyond the compliance boundary along the northern edge of the property. Based on
Figure ES-1, this plume extends along the entire length active ash basin.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 10

Figure ES-1: Belews Creek Steam Station October 2017 CSA Update Report
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 11

Figure ES-1 Legend: Belews Creek Steam Station October 2017 CSA Update Report
I FGFNn
AkEA OF CONCENTRATION IN GROUNDWATER
ABOVE NC2L BEE NOTE 5}
ASH SIN WASTE BOUNDARY
APPROXIMATE LANDFILL WASTE BOUNDARY
GENEFRALIZED GROUNOWATEIR FLOW DIRECTI0N
RESIDENTIAL UNIT
— DESIGNATED EFFLUENT CRANNEL Wl'TH FLOW DIRECTION
STREAM WITH FLOW DIRECTION
OU KE EN E RGY PROPERTY BOUN DARY
NOTE.,
i OCTOBER, 201$ AERIAL PHOT R1kPHY OBTAINED FROM OGLE EARTH PRO ON
SEPTEMBER 11, 2017. AERIAL DATC-D APRI L 8. N 17
2 STREAM FROM AUCC NRTR RI~PQRt. nIS
3 GENERALIZE1) GROUNDWATER F�OW DIRECTiON DASEO ON APR IL 3, 20$7 WATER
LEVEL DATA
A. PROKRTY BOUNDARY RRQV1QED BY QLk-F; EhIEROY
5. rENE1 >`LZED *REAL E NT OF MI ATgON REPRESENTED EIY NDAC L
EXCEED NCC OC4 .
BELEWS CREEK 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
6: Hybrid would meet the criteria of CAMA Option B. DEQ considered whether the proposed
closure option would prevent any post closure exceedances of the 2L groundwater quality
standard at the compliance boundary upon full closure implementation. Cross -sections B-B' and
C-C' were evaluated and can be seen in the figures below. These cross -sections represent
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=125 years
• upon completion of the hybrid option at t=0 years and
• hybrid option at t=118 years
The tables below summarize the results from the model simulations. The boron concentrations
depicted in each the tables represent the maximum boron concentration in any layer (ash,
saprolite, transition zone, and bedrock) of the model.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 13

Belews Creek Modeling Results
for Cross -Section B-B'
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
(ug/L)
(feet bgs)
(feet)
Current Conditions
4,000-10,000
140
1200
Completion of Final
4,000-10,000
150
1200
Cover (t=0 yrs)
Final Cover
700-4,000
260
700
(t=125 yrs)
Completion of
4,000-10,000
145
1200
Hybrid (t=0 yrs)
Hybrid (t=118 yrs)
700-4,000
235
900
bgs — below ground surface
Belews Creek Modeling Results for Cross -Section C-C'
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
(ug/L)
(feet bgs)
(feet)
Current Conditions
4,000-10,000
325
6S0
Completion of Final
4,000-10,000
330
650
Cover (t=0 yrs)
Final Cover
700-4,000
550
700
(t=125 yrs)
Completion of
4,000-10,000
310
700
Hybrid (t=0 yrs)
Hybrid (t=118 yrs)
700-4,000
440
750
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 118 to 125 years
beyond completion of closure, the area of the plume requiring remediation remains extensive.
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.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 14

BELEWS CREEK CURRENT CONDITIONS IN 2017
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
REEK CLOSURE DETERMINATION - APRIL 1, 2019 - 15

BELEWS CREEK UPON COMPLETION OF FINAL COVER, 2025 t = r
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
CLOSURE DETERMINATION - APRIL 1, 2019 - 16

BELEWS CREEK FINAL COVER, 2150, t = 125 years
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
NS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 17

BELEWS CREEK UPON COMPLETION OF HYBRID IN 2032, t = "
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 18

BELEWS CREEK HYBRID, 2150, t = 118 years
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
DETERMINATION - APRIL 1, 2019 - 19

BELEWS CREEK CURRENT CONDITIONS IN 2017
CROSS SECTION B-B' (VIEWED FROM DAM LOOKING SW)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
boundary
n w� •
Belews c
Ash 1-9
SaprolitE
TZ 15
Bedrock
A -A' 850 ft
B-B' 850 ft
C-C' 1000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 20

BELEWS CREEK UPON COMPLETION OF FINAL COVER, t = C
CROSS SECTION B-B' (VIEWED FROM DAM LOOKING SW)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
boundary
Belews Creek model layer
Ash 1-9
Saprolite 10-14
TZ 15
Bedrock 16-27
Vel
exi
40002
A -A' 850 ft
B-B' 850 ft
C-C' 1000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 21

BELEWS CREEK FINAL COVER, t =
CROSS SECTION B-B' (VIEWED FROM DAM LOOKING SW)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
Belews Creek model layers:
Ash 1-9
Saprolite
TZ 15
Bedrock
compliance
boundary
B B'
I
I
I
�1
40002
KIOX
A -A' 850 ft
B-B' 850 ft
C-C' 1000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 22

11,
T
E
BELEWS CREEK UPON COMPLETION OF HYBRID, t =
CROSS SECTION B-B' (VIEWED FROM DAM LOOKING SW)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance �yx g _ 1fr aa. i ,xnaaeea
boundaryBI ) 4 +-
+ 4 `
A -A'
850 ft
B-B'
850 ft
C-C'
1000 ft
D-D'
6000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 23

BELEWS CREEK HYBRID, t = 118 years
CROSS SECTION B-B' (VIEWED FROM DAM LOOKING SW)
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance aUom
4 4• �6ra 4
boundary
Belew
Ash 1
Saprol
TZ 1�
Bedre
A -A'
850 ft
B-B'
850 ft
C-C'
1000 ft
D-D'
6000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 24

BELEWS CREEK CURRENT CONDITIONS IN 2017
CROSS SECTION C-C' (VIEWED FROM E SIDE OF BLANKET DRAIN LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
Belews Creek model layers:
Ash 1-9
Saprolite 10-14
TZ 15
Bedrock 16-27
Vertical
exaggeration X 3
compliance 40002
C boundary �
1c
10 0
�h
5
1 —325 ft bls I
A -A' 850 ft
1
1 B-B' 850 ft
1
1 C-C' 1000 ft
1
1
1
1
1
-� BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 25

BELEWS CREEK UPON COMPLETION OF FINAL COVER, t = C
CROSS SECTION C-C' (VIEWED FROM E SIDE OF BLANKET DRAIN LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
C C
boundary
Belews Creek rnodpl laver, -
Ash 1-9
Saprolite 10-1
TZ 15
Bedrock 16-2
40002
A -A' 850 ft
B-B' 850 ft
C-C' 1000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 26

BELEWS CREEK FINAL COVER, t = 125 years
CROSS SECTION C-C' (VIEWED FROM E SIDE OF BLANKET DRAIN LOOKING WEST)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
C boundary C
1
Bele,
Ash
Sapr(
TZ
Bedr
40002
A -A' 850 ft
B-B' 850 ft
C-C' 1000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 27

BELEWS CREEK UPON COMPLETION OF HYBRID, t =
CROSS SECTION C-C' (VIEWED FROM E SIDE OF BLANKET DRAIN LOOKING WEST)
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
Cboundary
rM,�x � 1����0�� 1�'Afu4 e-0•,r i,rqu.u.�ar�
4
Y• s r
J�
r LI
_ y 1
F
f
•e-1 x = F
A
-A'
850 ft
B-B'
850 ft
C-C'
1000 ft
D-D'
6000 ft
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 28

BELEWS CREEK HYBRID, t = 118 years
CROSS SECTION C-C' (VIEWED FROM E SIDE OF BLANKET DRAIN LOOKING WEST)
MAX BORON ANY LAYER (ug/L) green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
Belews Creek
Ash 1-9
Saprolite 10-
TZ 15
Bedrock 16-:
_ _ - •ham d- - _
A
-A'
850 ft
B-B'
850 ft
C-C'
1000 ft
D-D'
6000 ft
CLOSURE DETERMINATION - APRIL 1, 2019 - 29

ATTACHMENT B
RESPONSE TO COMMENTS
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 30

RESPONSE TO COMMENTS
I. Summary of Responses to Comments
The North Carolina Department of Environmental Quality (NCDEQ) received
approximately 1052 public comments regarding the Belews Creek Steam Station Ash Basin
Closure Options. Closure options considered at Belews Creek generally include closure -in -place,
closure -by -removal and hybrid closure. Comments received by NCDEQ include emails, letters,
two petitions (containing 275 and 340 signatures respectively) and video submissions. All but
one of the comments support full excavation of all ash materials from the ash basin.
The majority of the comments support closure by removal to a lined landfill without
specifying the location of the landfill. A sizeable minority specifically recommend excavating coal
ash and moving it to a lined onsite landfill, although one commenter expressed concern about
the onsite clear cutting of trees that may be required at Belews Creek to build the landfill. A small
minority of commenters want the coal ash moved out of state. No commenter supports the
hybrid closure option. No commenter unequivocally supports closure -in -place. However, one
commenter registered qualified support for this option. Several commenters support recycling
coal ash for various commercial product uses. A discussion of these and other related comments
follow.
II. Detailed Responses to Comments
A. Closure -In -Place
No comments were received which unequivocally favored closure -in -place. Of the
approximately 1,052 comments received, all but one expressly opposed closure -in -place. Many
commenters stated specific reasons for their opposition. The reasons cited in opposition to
closure -in -place include: water quality concerns, including concern that portions of the coal ash
basin are located in the groundwater below the water table and that the ash basin was built on
top of existing streams; concerns about increased risk of adverse health impacts, including
cancer, respiratory and other illnesses; concerns regarding Duke Energy's motives for proposing
closure -in -place; concerns regarding Duke Energy's credibility (citing Duke Energy's recent history
of criminal violations); concerns about climate -related impacts on coal ash closed in place,
including hurricanes and tropical storms; concerns for natural resources impacts, including both
plant and animal life; concerns about recreational activities involving natural resources such as
boating, swimming and fishing; concerns about fair and equal safety protections from the effects
of coal ash for the Belews Creek area, citing coal ash removal and storage in lined landfills in
South Carolina, Virginia and at eight other coal ash sites in North Carolina; concerns that closure -
in -place both violates state and federal statutes and regulations and also grants Duke Energy
arbitrary and capricious preferential treatment in a manner that is not granted to anyone else;
concerns over the effectiveness and costs of oversight of long-term monitoring; concerns that
closure -in -place sends the wrong message to businesses and persons considering relocation to
North Carolina by adversely impacting the reputation of North Carolina nationally, including the
negative impact on both property values and the desirability of North Carolina as a place for
business relocation; concerns about general impacts to future generations, including "kicking the
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 31

problem down the road"; concerns about environmental justice issues and adverse impacts on
minorities and the poor; concerns that Duke Energy is avoiding a real financial cost of coal
generated electricity such that the market cannot make accurate cost comparisons to other
energy sources; concerns about adverse effects on tourism; concerns about the adverse impacts
on the fisheries industry; concerns about the health and safety risks associated with dam failure;
concerns that the overwhelming majority of public comments opposing closure -in -place must be
heard and followed.
Response: DEQ elects CAMA Option A (excavation and disposal to a lined landfill). DEQ
does not elect closure -in -place under CAMA Option B or C.
One commenter equivocally supported closure -in -place under certain conditions. That
comment is summarized below.
Comment: One commenter indicated that closure -in -place could potentially be a viable
option, but did not support the specific proposal for closure -in -place presented by Duke Energy.
He commented that the Duke Energy closure -in -place option allows for saturated pond ash
deposits to remain, thus creating a "wet cap" closure -in -place. He stated his opinion that
additional study, monitoring and safeguards would be needed to see if a different closure -in -
place option could comply with applicable regulations and be safely utilized. He recommended
a potential closure -in -place that steadily dewaters the coal ash impoundment, monitors the
results from the dewatering over several months and uses the collected data to verify or update
groundwater modeling at the site. The collected data and modeling would determine if closure -
in -place is viable and if not, then closure -by -removal could be employed.
Response: NCDEQ rejects the closure -in -place option and elects excavation under CAMA
Option A for Belews Creek. The excavated coal ash will be placed in a lined landfill.
B. Hybrid Option
No comments were received supporting the hybrid option. Several comments expressly
opposed the hybrid option for many of the reasons cited in opposition to closure -in -place,
including but not limited to health and safety concerns, water quality concerns, concerns about
the natural environment and concerns that the problem was being left for future generations.
Response: DEQ elects CAMA Option A (excavation and disposal to a lined landfill).
DEQ does not elect closure -in -place under CAMA Option B or C.
C. Closure -By -Removal
1. Closure -by -Removal With No Location Specified
Comment: Approximately 956 commenters stated in a form email that they were
supportive of closure -by -removal to a dry lined landfill. The comment in that form email states
the following:
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 32

"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. 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 other sites in North
Carolina and all of its sites in South Carolina —our families and our community deserve the same
protections".
Response: NCDEQ rejects the closure -in -place option and elects excavation under CAMA
Option A for Belews Creek.
2. Closure -By -Removal to Lined Onsite Landfill
Comment: Approximately 51 comments were submitted using a second form email.
These commenters supported the closure -by -removal of coal ash from unlined pits and placing
it in dry, lined storage located on Duke Energy property away from Little Belews Creek and the
Dan River:
• 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 Little Belews Creek and
the Dan River.
• Duke Energy plans to leave its coal ash sitting in the groundwater at Belews Creek,
where it will keep polluting our groundwater, lakes, streams and rivers. Recent
monitoring shows Duke Energy is polluting the groundwater surrounding Belews Creek
with toxic 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.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 33

• Duke Energy can dispose all the ash from its leaking ponds onsite in a safe, lined landfill.
Ash need not travel through the community or to other communities.
• Duke Energy cannot exaggerate traffic concerns while downplaying the community's
real concern: Duke Energy's water pollution. Excavation will not significantly increase
offsite trucking if Duke Energy uses an onsite landfill, and only excavation will remove the
source of the water pollution.
• 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 would be minimal. Duke Energy's
consultant estimates that 110 trucks currently travel near Belews Creek on community
roads every day. Excavation to onsite storage would add only two more trucks on
community roads each day, compared to six 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: NCDEQ has determined that closure -by -removal is the best closure option for
Belews Creek. The excavated coal ash will be placed in a lined landfill. The location of the lined
landfill will be determined at a later date; landfill location should be addressed in the proposed
closure plan which must be submitted by August 1, 2019.
D. Other Comments
1. Comment Addressing Fairness and Consistency
Comment: Many commenters, in form emails, individualized emails, submitted petitions
and video submissions, voiced their concern that persons in the Belews Creek area be treated
fairly and consistently with other persons both in the state and in the region regarding the risks
of coal ash. They noted that coal ash is being removed at eight other sites in North Carolina, all
Duke Energy sites in South Carolina and that coal ash is being removed in Virginia. The
commenters assert that their community deserves the same protections with respect to the
treatment of coal ash.
Response: NCDEQ has determined that closure -by -removal is the best closure option for
Belews Creek. The excavated coal ash will be placed in a lined landfill.
2. Comment Addressing Cost and Accountability
Comment: Several commenters stated that Duke Energy should have to pay for all costs
associated with the removal and storage of coal ash in dry lined landfill. Commenters pointed to
Duke Energy's recent criminal record and Duke Energy's decision to create the situation in the
first place. Several commenters stated that Duke Energy created the mess and Duke Energy
should clean up the mess. Some commenters supported sharing the costs with taxpayers. Other
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 34

commenters emphasized that the coal ash must be removed and that the responsibility for costs
was a secondary issue.
Response: NCDEQ has not been granted statutory authority to determine who will pay
the costs associated with closure -by -removal at Belews Creek, including costs associated with
storage of excavated coal ash in a lined landfill.
3. Comment Addressing the Recycling of Coal Ash
Comment: Several commenters proposed the recycling of coal ash. They proposed
various means by which recycling could occur, including encasing in cement bricks, concrete,
placing in wall board and other proposed uses. One commenter stated that Duke Energy could
extract the usable portion of coal ash, fly ash, and put it to productive use instead of disposing of
it. Another commenter stated that Duke Energy's failure to process ash such that it could be
recycled has resulted in ash being imported from other countries for use in products in the United
States. Another commenter emphasized the importance of researching and developing new uses
for recycled ash. One commenter proposed the ash be stored in a lined basin in a manner such
that the ash could be accessed for recycling in the future.
Response: The proposed closure plan, which must be submitted not later than August 1,
2019, may provide additional information on several issues involved with closure -by -removal,
including whether Duke Energy plans to recycle coal ash excavated at Belews Creek. Pursuant to
the requirements of the Coal Ash Management Act, the public will receive notice of the proposed
closure plan and given the opportunity to comment.
4. Comments Addressing Landfill Design, Groundwater Monitoring and Safety of
Workers Engaged In Removal of Ash and Construction of Lined Landfill
Comment: Several commenters expressed the need for the protection of worker safety
during the removal of the coal ash, the construction of a dry lined landfill and during the
placement of ash into the new landfill. Commenters proposed that appropriate particulate masks
should be worn, removal precautions should be taken, OSHA inspections should be performed
and protective suits should be worn as necessary.
Response: Duke Energy will be required to meet all applicable legal statutes and
regulations addressing worker safety at Belews Creek. Generally, the statutory authority to
regulate worker safety laws is vested in state and federal agencies other than NCDEQ.
Comment: Several commenters emphasized the importance of careful, independent
research and analysis of the best options for long term storage, including emphasis on the use of
best technologies and not focusing on short term savings. The landfills should be built above
minimum standards with long-term safeguards, use of best liner technologies, the inclusion of
redundant liners and the placement of the landfill should be based on best science after
investigation and ongoing monitoring of groundwater, away from rivers, lakes and aquifers. One
commenter proposed double lining to include two feet of clay on the exterior with durable lining
impervious to water.
Response: The proposed closure plan, which must be submitted not later than August 1,
2019, may provide additional information on several issues involved with closure -by -removal,
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 35

including whether Duke Energy plans to recycle coal ash excavated at Belews Creek. Pursuant to
the requirements of the Coal Ash Management Act, the public will receive notice of the proposed
closure plan and given the opportunity to comment.
Comment: Several commenters emphasized the importance of ongoing monitoring of
groundwater and voiced skepticism regarding the reliability of monitoring by Duke Energy. One
commenter proposed that monitoring results should be full, public and transparent, with results
accessible by internet and in other ways easy for the public to access. Another commenter
proposed independent third -party verification in some instances of data produced by Duke
Energy. One commenter proposed that Duke Energy be required to monitor all necessary data
without "cherry picking" what to monitor in order to avoid liability.
Response: The proposed closure plan, which must be submitted not later than August 1,
2019, may provide additional information on several issues involved with closure -by -removal,
including whether Duke Energy plans to recycle coal ash excavated at Belews Creek. Pursuant to
the requirements of the Coal Ash Management Act, the public will receive notice of the proposed
closure plan and given the opportunity to comment.
S. Comments Addressing Environmental Justice
Comment: Several commenters raised concerns regarding environmental justice issues.
They were concerned that minorities and poor communities bear a disproportionate amount of
the negative health and economic consequences resulting from coal ash. They expressed
concern that these negative impacts affect a portion of the population that has the least voice to
respond.
Response: NCDEQ has determined that closure -by -removal is the best closure option for
Belews Creek. The excavated coal ash will be placed in a lined landfill.
6. Comments Addressing Health, Safety And Natural Resources Damage Associated
With Potential Dam Failure At The Belews Creek Ash Basin
Comment: Several commenters expressed concern about the potentially catastrophic
health and safety risks associated with dam failure at the Belews Creek ash basin. Commenters
expressed concern about the potential loss of human life, destruction of property and the
destruction of water quality and natural resources (including both plant and animal life).
Response: The excavated coal ash will be placed in a lined landfill. The proposed closure
plan for Belews Creek, which must be submitted not later than August 1, 2019, should provide
specific information relevant to this comment, including Duke Energy's plans to address the
Belews Creek ash basin dam. Pursuant to the requirements of the Coal Ash Management Act, the
public will receive notice of the proposed closure plan and given the opportunity to comment.
BELEWS CREEK CLOSURE DETERMINATION - APRIL 1, 2019 - 36

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
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.
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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.
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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
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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.
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