NC0004979_Allen_Appendix A_20191231

Corrective Action Plan Update December 2019
Duke Energy Carolinas, LLC - Allen Steam Station SynTerra
FI U ► M. I,
REGULATORY CORRESPONDENCE
NCDENR. August 13, 2014. Notice of Regulatory Requirements Letter
NCDEMLR. August 22, 2016. Dam Safety Repair Record Documentation
NCDEMLR. November 21, 2016. Dam Safety Repair Record Documentation
NCDEMLR. November 21, 2016. Dam Safety Repair Record Documentation (2)
NCDEMLR. January 18, 2017. Dam Safety Repair Record Documentation (2)
NCDEMLR. January 18, 2017. Dam Safety Repair Record Documentation
NCDEMLR. January 19, 2017. Dam Safety Repair Record Documentation
NCDWM. June 30, 2017. Notice of No Further Action
NCDEQ. July 7, 2017. Background Soil and Groundwater Dataset Review
NCDEQ. October 11, 2017. Approval of Provisional Background Threshold
Values
NCDEQ. April 27, 2018, CAP Content for Coal Ash Facilities
NCDEQ. May 14, 2018. Approval of Revised Background Threshold Values
Letter and Attachment

Corrective Action Plan Update December 2019
Duke Energy Carolinas, LLC - Allen Steam Station SynTerra
APPENDIX A (CONTINUED)
REGULATORY CORRESPONDENCE
NCDEQ. June 11, 2018. Review Comments for 2018 Comprehensive Site
Assessment Update
NCDEQ. November 13, 2018. Final Classification of CCR Surface
Impoundment
Anchor QEA. January 29, 2019. December 2018 Free Product Recovery
Report
NCDEQ. January 2019. Position Supporting Rationale for Proposed Duke
Energy Interpretation and Adjustment
NCDEQ. April 1, 2019. Final CCR Surface Impoundment Closure
Determination Report
NCDEQ. April 4, 2019. 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

August 12, 2014
GUIDELINES FOR COMPREHENSIVE SITE ASSESSMENT
This document provides guidelines for those involved in the investigation of
contaminated soil and/or groundwater, where the source of contamination is from:
■ Incidents caused by activities subject to permitting under G.S. 143-215.1
■ Incidents caused by activities subject to permitting under G.S. 87-88
■ Incidents arising from agricultural operations, including application of
agricultural chemicals, but not including unlawful discharges, spills or
disposal of such chemicals
Comprehensive Site Assessment (CSA)
NOTE: Regional Offices may request additional information in support of the CSA to aid
in their review and will not approve the CSA if any of the elements specified below have
not been included or have not been sufficiently addressed
Minimum Elements of the Comprehensive Site Assessment Report:
A. Title Page
• Site name, location and Groundwater Incident number (if
assigned) and Permit Number;
• Date of report;
• Responsible Party and/or permiee, including address and
phone number;
• Current property owner including address and phone
number;
• Consultant/contractor information including address and
phone number;
• Latitude and longitude of the facility; and
• Seal and signature of certifying P.E. or P.G., as appropriate.
B. Executive Summary
The Executive Summary should provide a brief overview of the pertinent
site information (i.e., provide sufficient information to acquaint the reader
with the who, what, when, where, why and how for site activities to date).
1. Source information:
Type of contaminants
2. Initial abatement/emergency response information.
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August 12, 2014
3. Receptor information:
•
Water supply wells;
•
Public water supplies (wells, surface water intakes);
•
Surface water bodies;
•
Wellhead protection areas;
•
Deep aquifers in the Coastal Plain physiographic region;
•
Subsurface structures; and
•
Land use.
4. Sampling/investigation results:
•
Nature and extent of contamination;
•
Maximum contaminant concentrations;
•
Site hydrogeology.
5. Conclusions
and recommendations.
C. Table of Contents
• First page number for each section listed.
• List of figures (all referenced by number and placed in a
single section following contents text).
• List of tables (all referenced by number and placed in a single
section following contents text).
• List of appendices.
D. Site History and Source Characterization
• Provide a history of property ownership and use. Indicate
dates of ownership, uses of the site, and potential sources of
contaminants.
• Discuss the source(s) of contamination, including primary
and secondary sources.
• For permitted activities, describe nature of activity, permitted
waste, application of all instances of
over-application/irrigation of wastes or water
• Summarize assessment activities and corrective actions
performed to date including emergency response, initial
abatement, primary and secondary source removal.
• Discuss geographical setting and present/future surrounding
land uses.
E. Receptor Information
Provide a site map showing labeled well locations within a

August 12, 2014
minimum of 1500 feet of the known extent of contamination.
Key to the table and maps described.
NOTE: As the known extent of contamination changes, the
receptor survey must be updated to reflect the change. This
applies throughout the Receptor Information section.
• In table format, list all water supply wells, public or private,
including irrigation wells and unused wells, (omit those that
have been properly abandoned in accordance with 15A
NCAC 2C .0100) within a minimum of 1500 feet of the known
extent of contamination. Note whether well users are also
served by a municipal water supply.
• For each well, include well number, well owner and user
names, addresses and telephone numbers, use of the well,
well depth, well casing depth, well screen interval, and
distance from source of contamination;
NOTE: It will often be necessary to conduct any or all of the
following in order to ensure reliability in a water supply well
survey.
o Call the city/county water department to inquire about
city water connections,
o Visit door-to-door (make sure that you introduce
yourself and state your purpose to residents prior to
examining their property) to obtain accurate
description of water usage, and if some residents are
not at home, ask surrounding neighbors who are
home about the water usage at those residences.
Even if a public water line is available, some
residents still use their well water and are not
connected to the public water system; and
o Search for water meters and well houses.
• Site map showing location of subsurface structures (e.g.,
sewers, utility lines, conduits, basements, septic tanks,
drain fields, etc.) within a minimum of 1,500 feet of the known
extent of contamination;
• Table of surrounding property owner addresses;
• Discuss the availability of public water supplies within a
minimum of 1,500 feet of the source area, including the
distance and location to the nearest public water lines and
the source(s) of the public water supply;
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August 12, 2014
• Identify all surface water bodies (e.g., ditch, pond, stream,
lake, river) within a minimum of 1,500 feet of the source of
contamination;
• Determine the location of any designated wellhead protection
areas as defined in 42 USC 300h-7(e) within a minimum of
1,500 feet of the source of contamination. Identify and
discuss the location of the water supply well(s) for which the
area was designated a wellhead protection area, and the
extent of the protected area. Include information about the
well owner, well -construction specifications (especially at
screened intervals), pumping rate and pumping schedule.
Information regarding designated wellhead. protection areas
may be obtained by contacting the Public Water Supply
Section at [phone];
• Discuss the uses and activities (involving possible human
exposure to contamination) that could occur at the site and
adjacent properties. Examples of such activities and uses
include but are not limited to use of a property for an office,
manufacturing operation, residence, store, school, gardening
or farming activities, recreational activities, or undeveloped
land;
• Determine whether the contaminated area is located in an
area where there is recharge to an unconfined or
semi -confined deeper aquifer that is being used or may be
used as a source of drinking water. Based on a review of
scientific literature on the regional hydrogeology and well
construction records and lithological logs for deeper wells in
the area, identify and describe the deep aquifers underlying
the source of contamination. Include information on the depth
of the deep aquifer in relation to the surficial saturated zone,
the lithology and hydraulic conductivity of the strata between
the surficial aquifer and the deeper aquifer, and the
difference in groundwater head between the surficial aquifer
and the deeper aquifer. Discuss the local and regional usage
of the deep aquifer and the draw down from major pumping
influences. Also, specify the distance from the source of
contamination to major discharge areas such as streams and
rivers. Cite all sources and references used for this
discussion.
NOTE: This requirement (last bullet) only pertains to
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August 12, 2014
contamination sources in the Coastal Plain physiographic region
as designated on a map entitled "Geology of !North Carolina"
published by the Department in 1985. However,
recharge/discharge, hydraulic conductivity, lithology, head
difference, etc. is also important information at mountains
and piedmont sites.
F. Regional Geology and Hydrogeology
Provide a brief description of the regional geology and hydrogeology. Cite
all references.
G. Site Geology and Hydrogeology
• Describe the soil and geology encountered at the site. Use
the information obtained during assessment activities (e.g.,
lithological descriptions made during drilling, probe surveys,
etc.). This information should correspond to the geologic
cross sections required in N. below; and
• Based on the results of the groundwater investigation,
describe the site hydrogeology, including a discussion of
groundwater flow direction, hydraulic gradient, hydraulic
conductivity and groundwater velocity. Discuss the effects of
the geologic and hydrogeological characteristics on the
migration, retardation, and attenuation of contaminants.
H . Soil Sampling Results
Using figures and tables to the extent possible, describe all soil sampling
performed to date and provide the rationale for sample locations, number
of samples collected, etc. Include the following information:
• Location of soil samples;
• Date of sampling;
• Type of soil samples (from excavation, borehole, Geoprobe,
etc.);
• Soil sample collection procedures (split spoon, grab, hand
auger, etc.)
• Depth of soil samples below land surface;
• Soil sample identification
• Soil sample analyses;
• Soil sample analytical results (list any contaminant detected
above the method detection limit); and
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August 12, 2014
• Identify any sample analytical results that exceed the
applicable cleanup levels.
NOTE: Information related to H. above should correspond to the
sampling location and sampling results maps required in N. below.
I . Groundwater Sampling Results
Using figures and tables to the extent possible describe the groundwater
sampling performed to date and provide the rationale for sample locations
(based on source and contaminant type), number of samples collected,
etc. Include the following information:
• Location of groundwater samples and monitoring wells;
• Date of sampling;
• Groundwater sample collection procedures (bailer, pump,
etc.);
• Groundwater sample identification and whether samples
were collected during initial abatement, CSA, etc.;
• Groundwater sample analyses;
• Groundwater sample analytical results (list any contaminant
detected above the method detection limit; and
• Identify all sample analytical results that exceed 15A NCAC
2L or interim standards.
NOTE: Information related to 1. above should correspond to the
sampling location and sampling results maps required in N. below.
J. Hydrogeological Investigation
Describe the hydrogeological investigation performed including all
methods, procedures and calculations used to characterize site
hydrogeological conditions. The following information should be discussed
and should correspond to the maps and figures required below:
• Groundwater flow direction;
• Hydraulic gradient (horizontal and vertical);
• Hydraulic conductivity;
• Groundwater velocity;
• Contaminant velocity;
• Slug test results; *
• Aquifer test results;
• Plume's physical and chemical characterization; and
• Fracture trace study if groundwater in bedrock is impacted.
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August 12, 2014
* Check with the Regional Office prior to performing these tests
and study to see if necessary for the site.
K. Groundwater Modeling Results
Groundwater modeling or predictive calculations may be necessary at
some sites (source area proximate to surface water, source area located
within wellhead protection area or source area overlying semi -confined or
unconfined deeper Coastal Plain aquifer) to verify, based on site specific
hydrogeological conditions, whether groundwater contamination poses a
risk to receptors. For contamination shown to pose a risk to receptors,
groundwater modeling may be necessary to determine an appropriate
cleanup level for contaminated groundwater. Modeling should illustrate the
input data used to complete the model and will generally be required for
natural attenuation proposals (see Groundwater Modeling Policy at
http://portal. ncdenr.org/web/wq/aps/a-wr)ro/policy).
NOTE: Input data for models should be derived from site specific
information with limited assumptions or estimates. All assumptions and
estimated values including biodegradation rates must be conservative
(predict reasonable worst -case scenarios) and must be well documented.
L. Discussion
• Nature and extent of contamination, including primary and
secondary source areas, and impacted groundwater and
surface water resources;
• Maximum contaminant concentrations;
• Contaminant migration and potentially affected receptors
M. Conclusions and Recommendations
If corrective action will be necessary, provide a preliminary evaluation of
remediation alternatives appropriate for the site. Discuss the remediation
alternatives likely to be selected. Note that for impacts to groundwater
associated with permitted activities, corrective action pursuant to 15A
NCAC 2L .0106(k), (1) and (m) is not applicable, unless provided for
pursuant to 15A NCAC 2L .0106(c) and (e) or through a variance from the
Environmental Management Commission (EMC).
N. Figures
9 71/2 minute USGS topographic quadrangle map showing an area

August 12, 2014
within a minimum of a 1,500-foot radius of the source of
contamination and depicting the site location, all water supply wells,
public water supplies, surface water intakes, surface water bodies,
designated well head protection areas, and areas of recharge to
deeper aquifers in the Coastal Plain that are or may be used as a
source for drinking water;
Site map locating source areas, site boundaries, buildings, all water
supply wells within a minimum of 1,500 feet, named
roads/easements/right-of-ways, subsurface utilities, product or
chemical storage areas, basements and adjacent properties, scale
and north arrow;
At least two geologic cross sections through the saturated and
unsaturated zones intersecting at or near right angles through the
contaminated area using a reasonable vertical exaggeration.
Indicate monitoring well/sample boring/sample locations and
analytical results for soil samples. Identify the depth to the water
table. Provide a site plan showing the locations of the cross
sections;
■ Site map(s) showing the results of all soil sampling conducted.
Indicate sampling identifications, sampling depths, locations and
analytical results;
■ Site map(s) showing the results of all groundwater sampling
conducted. Indicate sampling locations, monitoring well
identifications, sample identifications, and analytical results;
Separate groundwater contaminant iso-concentration contour maps
showing total volatile organic compound concentrations, total
semi -volatile organic compound concentrations and concentrations
for the most extensive contaminant. Maps should depict the
horizontal and vertical extent. Contour line for applicable 2L
standard should be shown in bold;
■ Site map(s) showing the elevation of groundwater in the monitoring
wells and the direction of groundwater flow. Contour the
groundwater elevations. Identify and locate the datum (arbitrary
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August 12, 2014
1000, USGS, NGVD) or benchmark. Indicate the dates that water
level measurements were made. There should be one map for each
series of water level measurements obtained;
■ Groundwater contaminant iso-concentration contour cross-section;
and
■ Site map(s) showing the monitoring wells.
NDTE: If possible, use a single base map to prepare site maps using a
map scale of 9 inch = 40 feet (or a smaller scale for large sites, if
necessary). Maps and figures should include conventional symbols,
notations, labeling, legends, scales, and north arrows and should
conform to generally accepted practices of map presentation such as
those enumerated in the US Geological Survey pamphlet, "Topographic
Maps".
O. Tables
List all water supply wells, public or private, including irrigation wells
and unused wells, (omit those that have been properly abandoned
in accordance with 15A NCAC 2C .0100) within a minimum of 1500
feet of the known extent of contamination For each well, include the
well number (may use the tax map number), well owner and user
names, addresses and telephone numbers, use of the well, well
depth, well casing depth, well screen interval and distance from the
source of contamination;
List the names and addresses of property owners and occupants
within or contiguous to the area containing contamination and all
property owners and occupants within or contiguous to the area
where the contamination is expected to migrate;
■ List the results for groundwater samples collected including sample
location; date of sampling; sample collection procedures (bailer,
pump, etc.); sample identifications; sample analyses; and sample
analytical results (list any contaminant detected above the method
detection limit in bold); and
List for each monitoring well, the monitoring well identification
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August 12, 2014
numbers, date water levels were obtained, elevations of the water
levels, the land surface, top of the well casing, screened interval
and bottom of the well.
P Appendices
• Boring logs and lithological descriptions;
• Well construction records;
• Standard procedures used at site for sampling, field equipment
decontamination, field screening, etc.;
• Laboratory reports and chain -of -custody documents;
• Copies of any permits or certificates obtained, permit number,
permitting agency, and
• Modeling data and results;
• Slug/pumping test data; and
• Certification form for CSA
10

August 12, 2014
DIVISION OF WATER RESOURCES
Certification for the Submittal of a Comprehensive Site Assessment
Responsible Party and/or Permittee:
Contact Person:
Address:
City: State: Zip Code:
Site Name:
Address:
City: State: Zip Code:
Groundwater Incident Number (applicable):
I, , a Professional Engineer/Professional Geologist
(circle one) for (firm or
company of employment) do hereby certify that the information indicated below is
enclosed as part of the required Comprehensive Site Assessment (CSA) and that
to the best of my knowledge the data, assessments, conclusions,
recommendations and other associated materials are correct, complete and
accurate.
(Each item must be initialed by the certifying licensed professional)
1. The source of the contamination has been identified. A list of all
potential
sources of the contamination are attached.
2. Imminent hazards to public health and safety have been identified.
3. Potential receptors and significant exposure pathways have been
identified.
4. Geological and hydrogeological features influencing the movement
of groundwater have been identified. The chemical and physical character of the
contaminants have been identified.
5. The CSA sufficiently characterizes the cause, significance and
extent of groundwater and soil contamination such that a Corrective Action Plan
can be developed. If any of the above statements have been altered or items not
initialed, provide a detailed explanation. Failure to initial any item or to provide
written justification for the lack thereof will result in immediate return of the CSA to
the responsible party.
(Please Affix Seal and Signature)
11

%DUKE
ENERGY,
October 9, 2015
Mr. Tom Reeder
Assistant Secretary for the Environment
North Carolina Department of Environmental Quality
1601 Mail Service Center
Raleigh, North Carolina 27699-1601
Subject: 90 Day Extension for Corrective Action Plans
Dear Assistant Secretary Reeder:
Harry K. Sideris
Senior Vice -President
Environmental, Health & Safety
526 South Church Street:
Mail Code ECUP
Charlotte, North Carolina 28202
704-382-4303
Duke Energy is requesting a 90 day extension for submittal of the final Groundwater Corrective Action
Plans per Section 130A-309.209(b)(1) of the Coal Ash Management Act of 2014. This extension request
was discussed with NCDEQ technical staff on September 23 and with NCDEQ management on October
2. It is Duke Energy's understanding based on these discussions that NCDEQ would like to divide the
CAP scope into two parts with the first part submitted on the original due dates and the second part
submitted 90 days later. The following due dates are our understanding based on these discussions:
Plant Name
CAP Part I Due Date
CAP Part 2 Due Date
Weatherspoon Power Plant
November 3, 2015
February 1, 2016
HF Lee Energy Complex
November 3, 2015
February 1, 2016
L.V. Sutton Energy Complex
November 3, 2015
February 1, 2016
Dan River Steam Station
November 12, 2015
February 10, 2016
Rogers Energy Complex
Riverbend Steam Station
November 16, 2015
February 14, 2016
February 14, 2016
February 19, 2016
February 19, 2016
February 19, 2016
November 16, 2015
November 21, 2015
November 21, 2015
Allen Steam Station
Buck Steam Station
Asheville Steam Electric Plant
Cape Fear Plant
Mayo Steam Electric Power _
Plant
November 21, 2015
December 1, 2015
February 29, 2016
December 1, 2015
December 1, 2015
February 29, 2016
Roxboro Steam Electric Plant
February 29, 2016
Marshall Steam Station —
December 7, 2015
March 6, 2016
Belews Creek Steam Stati=—December
8, 2015
March 7, 2016

Duke Energy proposes that the Part 1 CAP reports (submitted 90 days after the Groundwater Assessment
Reports were submitted) include: background information, a brief summary of the CSA findings, a brief
description of site geology and hydrogeology, a summary of the previously completed receptor survey, a
description of 2L and 2B exceedances, proposed site -specific groundwater background concentrations, a
detailed description of the site conceptual model, and groundwater flow and transport modeling. Part 2
would contain the remainder of the CAP including the risk assessment, alternative methods for achieving
restoration, conceptual plans for recommended corrective actions, implementation schedule, and a plan
for future monitoring and reporting.
If you have comments and/or questions, please direct them to me at 704-382-4303.
Sincerely,
Harry K. Sideris
Senior Vice -President
Environmental, Health & Safety

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
August 22, 2016
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Vice President
Duke Energy
400 S. Tryon Street, ST03H
Charlotte, NC 28202
PAT MCCRORY A-1
Governor
DONALD R. VAN DER VAART
Secretary
TRACY DAVIS
Director
RE: Dam Safety Order 16-01 Pertaining to Multiple Repairs to Multiple Dams
Allen Retired Ash Basin Dam (GASTO-016)
Allen Active Ash Basin Dam (GASTO-061)
Buck Steam Station Main Dam (ROWAN-047)
Cape Fear 1956 Ash Pond (Inactive) (CHATH-075)
Cape Fear 1963 Ash Pond Dam (Inactive) (CHATH-076)
Cape Fear 1970 Ash Pond Dam (Inactive) (CHATH-077)
Cape Fear 1978 Ash Pond Dam (CHATH-078)
Cliffside Active Ash Pond Downstream Dam (CLEVE-049)
Cliffside Inactive Ash Basin #5 Main Dam (RUTHE-070)
Dan River Active Primary Ash Basin (ROCKI-237)
Dan River Active Secondary Ash Basin (ROCKI-238)
Dan River Service Water Settling Pond Dam (ROCKI-241)
H.F. Lee Active Ash Pond (WAYNE-022)
Lincoln CT Raw Water Reservoir Dam (LINCO-042)
Marshall Active Ash Basin Dam (CATAW-054)
Roxboro East Ash Pond (PERSO-033)
Roxboro West Ash Pond South Rock Filter (PERSO-039)
Weatherspoon 1979 Ash Pond (ROBES-009)
Dear Mr. Hamrick:
Attached is an order, issued under the authority of the North Carolina Dam Safety Law of 1967,
specifically GS 143-215.32(b), requiring that repairs specified in the repair plans for the subject
dams that have been submitted to and approved by the Director of the Division of Energy,
Mineral', and Land Resources (DEMLR) shall be properly completed by specific deadlines stated
herein.
State of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center I Raleigh, North Carolina 27699
919 707 9220 T

A-2
Mr. George T. Hamrick
Order No. DS 16-01
Page 2
As -built drawings sealed by a Professional Engineer confirming that repairs approved by
DEMLR related to coal ash dams have been properly completed shall be submitted to DEMLR
by December 31, 2016 or an approvable Decommissioning Request pursuant to GS 143-
215.27A. shall be submitted to DEMLR by December 31, 2016. This requirement does not
include non -coal ash dams, ROCKI-241 and LINCO-042, which are addressed separately below.
These findings only include current jurisdictional dams and do not include dams that are
currently exempt from the North Carolina Dam Safety Law. A copy of the North Carolina Dam
Safety Law of 1967 is enclosed for your information.
As -built drawings sealed by a Professional Engineer confirming that repairs approved by
DEMLR related to non -coal ash dams, specifically ROCKI-241 and LINCO-042, have been
properly completed shall be submitted to DEMLR within one year from the date of issuance of
the certificate of approval for each respective repair pursuant to North Carolina Administrative
Code, Title 15A, Subchapter 2K, Section .0302 (15A NCAC 2K.0302).
If you wish to contest this Dam Safety Order, you must request a contested case hearing within
10 days after receiving this notice pursuant to GS 143-215.33. This request must be in the form
of a written petition that conforms to the requirements set forth in North Carolina General Statute
(NCGS) 15013-23. The original petition and one copy must be filed as follows:
Office of Administrative Hearings
6714 Mail Service Center
Raleigh, North Carolina 27699
Any questions about filing a petition may be directed to the Clerk of the Office of Administrative
Hearings by telephone at [phone].
A copy of the petition must also be served on the Department as follows:
Mr. Sam M. Hayes, General Counsel
Department of Environment and Natural Resources
1601 Mail Service Center
Raleigh, North Carolina 27699-1601

A-3
Mr. George T. Hamrick
Order No. DS 16-01
Page 3
Please note that failure to comply with this Dam Safety Order may result in the following
pursuant to GS 143-215.36:
The assessment of a civil penalty of not less than $100.00 nor more than $500.00 for each
dam. In the case of a willful failure to comply with this Dam Safety Order, a civil
penalty may be imposed in an amount up to $500.00 for each dam for each day of
violation. This penalty will begin to run from the deadline established in the Dam Safety
Order; and/or
2. A request to the Attorney General's Office for injunctive relief.
If you have any questions, please contact:
Mr. Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
1612 Mail Service Center
Raleigh, North Carolina 27699-1612
Telephone: [phone]
Please notify this office in writing within 10 business days of receiving this notice to provide
your plans and schedules for completion of the repairs to the subject dams.
Enclosures: Dam Safety Order 16-01
NC Dam Safety Law of 1967
cc: Tom Reeder, Assistant Secretary, DEQ
Surface Water Protection Regional Supervisors for WSRO, MRO, RRO, WARO and FRO
Matt Gantt, PE, DEMLR
Zahid Khan, DEMLR
John Holley, PE, DEMLR
Samir Dumpor, PE, DEMLR
Tim LaBounty, PE, DEMLR
(COUNTY EMERGENCY MANAGEMENT MANAGERS)

A-4
DAM SAFETY ORDER 16-01
FINDINGS AND ORDER OF THE DIRECTOR
DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES
Mr. George T. Hamrick
Vice President
Duke Energy
400 S. Tryon Street, ST03H
Charlotte, NC 28202
RE: Multiple Repairs to Multiple Dams
Allen Retired Ash Basin Dam (GASTO-016)
Allen Active Ash Basin Dam (GASTO-061)
Buck Steam Station Main Dam (ROWAN-047)
Cape Fear 1956 Ash Pond (Inactive) (CHATH-075)
Cape Fear 1963 Ash Pond Dam (Inactive) (CHATH-076)
Cape Fear 1970 Ash Pond Dam (Inactive) (CHATH-077)
Cape Fear 1978 Ash Pond Dam (CHATH-078)
Cliffside Active Ash Pond Downstream Dam (CLEVE-049)
Cliffside Inactive Ash Basin #5 Main Dam (RUTHE-070)
Dan River Active Primary Ash Basin (ROCKI-237)
Dan River Active Secondary Ash Basin (ROCKI-238)
Dan River Service Water Settling Pond Dam (ROCKI-241)
H.F. Lee Active Ash Pond (WAYNE-022)
Lincoln CT Raw Water Reservoir Dam (LINCO-042)
Marshall Active Ash Basin Dam (CATAW-054)
Roxboro East Ash Pond (PERSO-033)
Roxboro West Ash Pond South Rock Filter (PERSO-039)
Weatherspoon 1979 Ash Pond (ROBES-009)
Pursuant to the authority contained in North Carolina General Statute (NCGS) 143-215.32.(b) as
delegated to the Director in the North Carolina Administrative Code, Title 15A, Subchapter 2K,
Section .0302 (15A NCAC 2K.0302), the following repairs on the coal ash dams listed below, at
a minimum and as approved by the Division of Energy, Mineral, and Land Resources (DEMLR),
shall be properly completed and as -built drawings sealed by a Professional Engineer shall be
submitted to DEMLR by December 31, 2016 or an approvable Decommissioning Request
pursuant to GS 143-215.27A. must be submitted to this office by December 31, 2016. This Dam
Safety Order is being issued pursuant to NCGS 130A-309.213(d)(1)(b).
1. Allen Retired Ash Basin Dam (GASTO-016) has the following deficiencies that could
compromise its integrity: Spillway repair and the need for installation of new principal
spillway, vegetation/tree removal, and slope repair.

A-5
Mr. George T. Hamrick
DS 16-01
Page 2
2. Allen Active Ash Basin Dam (GASTO-061) has the following deficiencies that could
compromise its integrity: Spillway repair and the need for installation of new principal
spillway, and slope repair.
3. Buck Steam Station Main Dam (ROWAN-047) has the following deficiencies that could
compromise its integrity: Spillway repair and the need for installation of new spillway.
4. Cape Fear 1956 Ash Pond (Inactive) (CHATH-075) has the following deficiencies that
could compromise its integrity: Vegetation/tree removal.
5. Cape Fear 1963 Ash Pond Dam (Inactive) (CHATH-076) has the following deficiencies
that could compromise its integrity: Vegetation/tree removal.
6. Cape Fear 1970 Ash Pond Dam (Inactive) (CHATH-077) has the following deficiencies
that could compromise its integrity: Vegetation/tree removal.
7. Cape Fear 1978 Ash Pond Dam (CHATH-078) has the following deficiencies that could
compromise its integrity: Spillway repair and vegetation/tree removal.
8. Cliffside Active Ash Pond Downstream Dam (CLEVE-049) has the following
deficiencies that could compromise its integrity: Spillway and riser repair and the need
for installation of new spillway.
9. Cliffside Inactive Ash Basin #5 Main Dam (RUTHE-070) has the following deficiencies
that could compromise its integrity: The need for installation of new principal spillway.
10. Dan River Active Primary Ash Basin (ROCKI-237) has the following deficiencies that
could compromise its integrity: Slope repair.
11. Dan River Active Secondary Ash Basin (ROCKI-238) has the following deficiencies that
could compromise its integrity: Dredging and pond lowering project.

Mr. George T. Hamrick
DS 16-01
Page 3
12. H.F. Lee Active Ash Pond (WAYNE-022) has the following deficiencies that could
compromise its integrity: Slope repair and vegetation/tree removal.
13. Marshall Active Ash Basin Dam (CATAW-054) has the following deficiencies that could
compromise its integrity: The need for installation of new spillway.
14. Roxboro East Ash Pond (PERSO-033) has the following deficiencies that could
compromise its integrity: Pipe removal.
15. Roxboro West Ash Pond South Rock Filter (PERSO-039) has the following deficiencies
that could compromise its integrity: Spillway repair and the need for installation of new
spillway.
16. Weatherspoon 1979 Ash Pond (ROBES-009) has the following deficiencies that could
compromise its integrity: Clean toe drains and installation of aggregate drainage blanket,
vegetation/tree removal, and slope repair.
17. Regarding tree/vegetation removal projects: the trees/vegetation that have root systems
such that removal of the root systems could reduce slope stability and cause slope failure,
shall be removed after the structures have been dewatered and an approvable closure plan
has been approved by DEMLR. All other trees shall be removed by the deadline in this
Dam Safety Order.
As -built drawings sealed by a Professional Engineer confirming that repairs on the non -coal ash
dams listed below, at a minimum and as approved by DEMLR, have been properly completed
shall be submitted to DEMLR within one year from the date of issuance of the certificate of
approval for each respective repair pursuant to North Carolina Administrative Code, Title 15A,
Subchapter 2K, Section .0302 (15A NCAC 2K.0302):
Dan River Service Water Settling Pond Dam (ROCKI-241) has the following
deficiencies that could compromise its integrity: Spillway repair.
2. Lincoln CT Raw Water Reservoir Dam (LINCO-042) has the following deficiencies that
could compromise its integrity: Spillway repair.
Please note that all dams listed herein are classified in the high or intermediate hazard
classification category pursuant to 15A NCAC 2K.0105 because failure of the dam could
potentially pose a threat to human life and/or property downstream from the dam.

A-7
Mr. George T. Hamrick
DS 16-01
Page 4
Therefore, by the authority of NCGS 143-215.32(b) and 15A NCAC 2K.0302, it is hereby
Ordered that:
As -built drawings sealed by a Professional Engineer confirming that repairs approved by
DEMLR related to coal ash dams have been properly completed shall be submitted to
DEMLR by December 31, 2016 or an approvable Decommissioning Request pursuant to
GS 143-215.27A. must be submitted to DEMLR by December 31, 2016.
In addition, by the authority of 15A NCAC 2K.0302 and 15A NCAC 2K.0202(d), it is hereby
Ordered that:
As -built drawings sealed by a Professional Engineer confirming that repairs on the non -
coal ash dams, ROCKI-241 and LINCO-042, at a minimum and as approved by DEMLR,
have been properly completed shall be submitted to DEMLR within one year from the
date of issuance of the certificate of approval for each respective repair pursuant to North
Carolina Administrative Code, Title 15A, Subchapter 2K, Section .0302 (15A NCAC
2K.0302).
tNgl�
Date
and
of Energy, Mineral,

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
Final Approval of Repair
November 21, 2016
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Senior Vice President
Duke Energy
400 S. Tryon Street, ST06A
Charlotte, NC 28202
RE: Approval for Repairs— Scope 1 Addendum 2
Allen Retired Ash Basin Dam
Gaston County
State Dam ID: GASTO - 016
Dear Mr. Hamrick:
PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary
TRACY DAVIS
Director
This concerns the subject high hazard dam repaired pursuant to issuance of an Approval to
Repair dated May 16, 2016, as required by the Dam Safety Law of 1967. The repair pertained to
Scope 1 Addendum 2- Installation of an alternative spillway of the subject dam. Record
Drawings and the engineer's certification were received on November 10, 2016. The repair was
certified by Mr. Kevin L. Dill, PE of AECOM for the installation of the new spillway and by Mr.
David J. Goodman, PE of Fitzpatrick Engineering Group for the grouting of the retired riser and
the outlet conduit.
An inspection of this dam was made by Land Quality Section staff of the Mooresville Regional
Office on November 3, 2016. The dam was found to be in general conformance with the
approved plans and specifications, and continued operation of the dam is hereby approved with
following stipulation:
1. All necessary measures shall be undertaken to establish and maintain a vigorous stand of
permanent vegetation sufficient to restrain erosion.
The Land Quality Section staff will make periodic inspections of this dam to verify that the dam
is being maintained in good operating condition. These inspections, however, will be relatively
infrequent. It is advised that you closely inspect and monitor your dam, and that you notify your
State of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Mr. George T. Hamrick
Final Approval of Repair
November 21, 2016
Page 2 of 2
Allen Retired Ash Basin Dam
GASTO-016
engineer and the Division of Energy, Mineral, and Land Resources if you see or suspect any
problems concerning its safety. The Emergency Action Plan must be reviewed and updated as
needed by the owner or the owner's representative on an annual basis.
Please contact the Mooresville Regional Office at [phone] or a staff member of the Dam
Safety Program in the Raleigh Central Office at telephone number [phone] should you
have questions concerning this matter.
Sincerely,
Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
BSC/md
cc: Mr. Kevin L. Dill, PE, AECOM
Mr. David J. Goodman, PE, Fitzpatrick Engineering Group
Mr. Zahid Khan, Land Quality Regional Engineer
Mr. Jeff Poupart, Division of Water Resources
Mr. Randy Hart, Duke Energy
Filename: GASTO-016_20161121_COFA_ Allen Retired Ash Basin Dam -Scope 1 Addendum 2
Slate of North Carolina I Environments] Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
Final Approval of Repair
November 21, 2016
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Senior Vice President
Duke Energy
400 S. Tryon Street, ST06A
Charlotte, NC 28202
RE: Approval for Repairs— Scope 1 Addendum 2
Allen Active Ash Basin Dam
Gaston County
State Dam ID: GASTO - 061
Dear Mr. Hamrick:
PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary
TRACY DAVIS
Director
This concerns the subject high hazard dam repaired pursuant to issuance of an Approval to
Repair dated May 16, 2016, as required by the Dam Safety Law of 1967. The repair pertained to
Scope 1 Addendum 2- Installation of an alternative spillway of the subject dam. Record
Drawings and the engineer's certification were received on November 3, 2016. The repair was
certified by Mr. Kevin L. Dill, PE of AECOM for the installation of the new spillway and by Mr.
David J. Goodman, PE of Fitzpatrick Engineering Group for the grouting of the retired riser and
the outlet conduit.
An inspection of this dam was made by Land Quality Section staff of the Mooresville Regional
Office on November 3, 2016. The dam was found to be in general conformance with the
approved plans and specifications, and continued operation of the dam is hereby approved with
following stipulation:
1. All necessary measures shall be undertaken to establish and maintain a vigorous stand of
permanent vegetation sufficient to restrain erosion.
The Land Quality Section staff will make periodic inspections of this dam to verify that the dam
is being maintained in good operating condition. These inspections, however, will be relatively
infrequent. It is advised that you closely inspect and monitor your dam, and that you notify your
State of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Mr. George T. Hamrick Allen Active Ash Basin Dam
Final Approval of Repair GASTO-061
November 21, 2016
Page 2 of 2
engineer and the Division of Energy, Mineral, and Land Resources if you see or suspect any
problems concerning its safety. The Emergency Action Plan must be reviewed and updated as
needed by the owner or the owner's representative on an annual basis.
Please contact the Mooresville Regional Office at [phone] or a staff member of the Dam
Safety Program in the Raleigh Central Office at telephone number [phone] should you
have questions concerning this matter.
Sincerely,
Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
BSC/md
cc: Mr. Kevin L. Dill, PE, AECOM
Mr. David J. Goodman, PE, Fitzpatrick Engineering Group
Mr. Zahid Khan, Land Quality Regional Engineer
Mr. Jeff Poupart, Division of Water Resources
Mr. Randy Hart, Duke Energy
Filename: GASTO-061_20161 l21_COFA_ Allen Active Ash Basin Dam -Scope 1 Addendum 2
State of North Carolina I Environmental Quality I Energy, Mineral, and land Resomem
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Energy, Mineral
and Land Resources
ENVIRONMENTAL OVALITY
Final Approval of Repair
January 18, 2017
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Senior Vice President
Duke Energy
400 S. Tryon Street, ST06A
Charlotte, NC 28202
RE: Approval to Repair— Scope 5
Allen Retired Ash Basin Dam
Gaston County
State Dam ID: GASTO - 016
Dear Mr. Hamrick:
ROY COOPER
(invemar
WILLIAM G. ROSS, JR.
Acting Secretary
TRACY E. DAVIS
nitecMr
This concerns the subject high hazard dam repaired pursuant to issuance of an Approval to
Repair dated October 22, 2015, as required by the Dam Safety Law of 1967. The repair pertained
to Scope 5- Engineered plan to address shallow slope stability concerns. Record Drawings and
the engineer's certification were received on September 21, 2016. The repair was certified by
Mr. Walter G. Kutschke, PhD., PE of AECOM.
An inspection of this dam was made by Land Quality Section staff of the Mooresville Regional
Office on September 28, 2016. The dam was found to be in general conformance with the
approved plans and specifications, and continued operation of the dam is hereby approved.
The Land Quality Section staff will make periodic inspections of this dam to verify that the dam
is being maintained in good operating condition. These inspections, however, will be relatively
infrequent. It is advised that you closely inspect and monitor your dam, and that you notify your
engineer and the Division of Energy, Mineral, and Land Resources if you see or suspect any
problems concerning its safety. The Emergency Action Plan must be reviewed and updated as
needed by the owner or the owner's representative on an annual basis.
Slate of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 1

Mr. George T. Hamrick
Final Approval of Repair -Scope 5
January 18, 2017
Page 2 of 2
Allen Retired Ash Basin Dam
GASTO-016
Please contact the Mooresville Regional Office at [phone] or a staff member of the Dam
Safety Program in the Raleigh Central Office at telephone number [phone] should you
have questions concerning this matter.
Sincerely,
Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
BSC/md/fmt
cc: Mr. Walter G. Kutschke, PhD., PE of AECOM
Mr. Zahid Khan, DEMLR Regional Engineer, MRO
Mr. Jeff Poupart, Division of Water Resources
Mr. Randy Hart, Duke Energy
Filename: GASTO-016_20170118_COFA_ Allen Retired Ash Basin Dam -Scope 5
State of North Carolina I Environmental Quality I Energy, Mineral, and land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
Final Approval of Repair
January 18, 2017
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Senior Vice President
Duke Energy
400 S. Tryon Street, ST06A
Charlotte, NC 28202
RE: Approval to Repair— Scope 3
Allen Retired Ash Basin Dam
Gaston County
State Dam ID: GASTO - 016
Dear Mr. Hamrick:
ROY COOPER
Gove,nor
WILLIAM G. ROSS, JR.
Acting Secretary
TRACY E. DAVIS
Director
This concerns the subject high hazard dam repaired pursuant to issuance of an Approval to
Repair dated December 8, 2014, as required by the Dam Safety Law of 1967. The repair
pertained to Scope 3- Vegetation removal. Record Drawings and the engineer's certification were
received on September 19, 2016. The repair was certified by Mr. Robert E. Smith, Jr, PE of
AMEC.
An inspection of this dam was made by Land Quality Section staff of the Mooresville Regional
Office on September 28, 2016. The dam was found to be in general conformance with the
approved plans and specifications, and continued operation of the dam is hereby approved.
The Land Quality Section staff will make periodic inspections of this dam to verify that the dam
is being maintained in good operating condition. These inspections, however, will be relatively
infrequent. It is advised that you closely inspect and monitor your dam, and that you notify your
engineer and the Division of Energy, Mineral, and Land Resources if you see or suspect any
problems concerning its safety. The Emergency Action Plan must be reviewed and updated as
needed by the owner or the owner's representative on an annual basis.
State of Noah Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mal Service Center 1512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Mr. George T. Hamrick
Final Approval of Repair -Scope 3
January 18, 2017
Page 2 of 2
Allen Retired Ash Basin Dam
GASTO-016
Please contact the Mooresville Regional Office at [phone] or a staff member of the Dam
Safety Program in the Raleigh Central Office at telephone number [phone] should you
have questions concerning this matter.
Sincerely,
-
f�Z�
Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
BSC/md
cc: Mr. Robert E. Smith, Jr, PE, AMEC.
Mr. Zahid Khan, DEMLR Regional Engineer, MRO
Mr. Jeff Poupart, Division of Water Resources
Mr. Randy Hart, Duke Energy
Filename: GASTO-016 20170118_COFA_ Allen Retired Ash Basin Dam -Scope 3
State of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Energy, Mineral
and Land Resources
ENVIRONMENTAL QUALITY
Final Approval of Repair
January 19, 2017
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. George T. Hamrick
Senior Vice President
Duke Energy
400 S. Tryon Street, ST06A
Charlotte, NC 28202
RE: Approval to Repair— Scope 5
Allen Active Ash Basin Dam
Gaston County
State Dam ID: GASTO - 061
IITT"35i=. , tFT119 M
ROY COOPER
Governor
WILLIAM G. ROSS, JR.
Acling Secretary
TRACY E. DAVIS
Direclor
This concerns the subject high hazard dam repaired pursuant to issuance of an Approval to
Repair dated October 21, 2015, as required by the Dam Safety Law of 1967. The repair pertained
to Scope 5- Engineered plan to address shallow slope stability concerns. Record Drawings and
the engineer's certification were received on September 26, 2016. The repair was certified by
Mr. Walter G. Kutschke, PhD., PE of AECOM.
An inspection of this dam was made by Land Quality Section staff of the Mooresville Regional
Office on September 28, 2016. The dam was found to be in general conformance with the
approved plans and specifications, and continued operation of the dam is hereby approved.
The Land Quality Section staff will make periodic inspections of this dam to verify that the dam
is being maintained in good operating condition. These inspections, however, will be relatively
infrequent. It is advised that you closely inspect and monitor your dam, and that you notify your
engineer and the Division of Energy, Mineral, and Land Resources if you see or suspect any
problems concerning its safety. The Emergency Action Plan must be reviewed and updated as
needed by the owner or the owner's representative on an annual basis.
State of Noah Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Mr. George T. Hamrick
Final Approval of Repair -Scope 5
January 19, 2017
Page 2 of 2
Allen Active Ash Basin Dam
GASTO-061
Please contact the Mooresville Regional Office at [phone] or a staff member of the Dam
Safety Program in the Raleigh Central Office at telephone number [phone] should you
have questions concerning this matter.
Sincerely,
Brian Shane Cook, PE, LSIT
State Dam Safety Engineer
Land Quality Section
BSC/fmt
cc: Mr. Walter G. Kutschke, PhD., PE of AECOM
Mr. Zahid Khan, DEMLR Regional Engineer, MRO
Mr. Jeff Poupart, Division of Water Resources
Mr. Randy Hart, Duke Energy
Filename: GASTO-061 20170119_COFA_ Allen Active Retired Ash Basin Dam -Scope 5
State of North Carolina I Environmental Quality I Energy, Mineral, and Land Resources
1612 Mail Service Center 1 512 N. Salisbury St. I Raleigh, NC 27699
919 707 9220 T

Waste Management
ENVIR6NMENTAL ©VALITY
June 30, 2017
Duke Energy Corporation
Mail Code EC13K
526 South Church Street
Charlotte, North Carolina 28202
Attention: Rick Powell
C 0 - ROY COOPER
Governor
MICHAEL S. REGAN
secretary
MICHAELSCOTT
Director
Re: Notice of No Further Action
15A NCAC 2L .0407(d)
Risk -based Assessment and Corrective Action
for Petroleum Underground Storage Tanks
Allen Steam Plant
253 Plant Allen Road, Belmont
Gaston County
Incident Number: 18137 & 40625
Risk Classification: Low
Dear Mr. Powell:
The UST Section determines that no further action is warranted for this incident. All required
actions have been completed. On May 30, 2017, the UST Section received a certified copy of the Notice
of Residual Petroleum which is filed with the Register of Deeds. On June 2, 2017, the UST Section was
provided with proof of receipt of the conditional Notice of No Further Action letter or of refusal by the
addressee to accept delivery of the letter or with a description of the manner in which the letter was
posted.
This determination shall apply unless the UST Section later finds that the discharge or release
poses an unacceptable risk or a potentially unacceptable risk to human health or the environment.
Pursuant to Title 15A NCAC 21, .0407(a) you have a continuing obligation to notify the Department of
Environmental Quality of any changes that might affect the risk or land use classifications that have been
assigned.
Be advised that as groundwater contamination exceeds the groundwater quality standards
established in Title 15A NCAC 2L .0202, groundwater within the area of contamination or within the area
where groundwater contamination is expected to migrate is not suitable for use as a water supply. Be
advised that as soil contamination exceeds the residential MSCCs, the property containing the
contamination is suitable only for industrial/ commercial use or restricted residential use (The term
"residential is inclusive of, but not limited to, private houses, apartment complexes, schools, nursing
homes, parks, recreation areas and day care centers), as stipulated in the Notice of Residual Petroleum
(attached).
State of North Carolina I Environmental Quality I waste Management
Mooresville Regional Office 1 610 East Center Avenue. Suite 301 1Mooresville; NC 28115
7046631699

Duke Energy Corporation
June 30, 2017
Page 2 of 2
Interested parties may examine the Soil Cleanup Report/ Site Closure Request by contacting this
regional office and may submit comments on the site to the regional office at the address or telephone
number listed below.
This No Further Action determination applies only to the subject incident; for any other incidents
at the subject site, the responsible party must continue to address contamination as required.
If you have any questions regarding this notice, please contact me at the address or telephone
number listed below.
Sincerely,
Brad C. Newton, P.G.
Hydrogeologist II
Mooresville Regional Office
UST Section, Division of Waste Management, NCDEQ
cc: Gaston County Health Department

wi
Waste Management
ENVIRONMENTAL QUALITY
May 17, 2017
Duke Energy Corporation
Mail Code EC13K
526 South Church Street
Charlotte, North Carolina 28202
Attention: Rick Powell
IZ
Dear Mr. Powell:
ROY COOPER
Gbvemor
..„ MICHAEL S. REGAN.....,,.,
secretary
MICHAEL SCOTT
D&eaor
Conditional Notice of No Further Action
15A NCAC 2L .0407(d)
Risk -based Assessment and Corrective Action
for Petroleum Underground Storage Tanks
Allen Steam Plant
253 Plant Allen Road, Belmont
Gaston County
Incident Numbers: 18137 & 40625
Risk Classification: Low
Ranking:
The Notice of Residual Petroleum received by the UST Section, Division of Waste Management,
Mooresville Regional Office on May 15, 2017 has been reviewed. The review indicates that soil
contamination exceeds the residential maximum soil contaminant concentrations (MSCCs) established in
Title 15A NCAC 2L .0411 and groundwater contamination meets the cleanup requirements for a low -risk
site but exceeds the groundwater quality standards established in Title 15A NCAC 2L .0202.
The UST Section determines the.subject incident to be eligible conditionally for no further action
status. However, final approval of no further action status is contingent on the filing of the approved
NRP (attached) with the Register of Deeds in the county in which the release is located, verified by the
receipt of a certified copy of the filed NRP by this office; and on receipt of confirmation that public notice
requirements have been completed, as described in the following paragraphs.
Be advised that as groundwater contamination exceeds the groundwater quality standards
established in Title 15A NCAC 2L .0202, groundwater within the area of contamination or within the area
where groundwater contamination is expected to migrate is not suitable for use as a water supply. Be
advised that as soil contamination exceeds the residential MSCCs, the property containing the
contamination is suitable only for industrial/ commercial use or restricted residential use (The term
"residential is inclusive of, but not limited to, private houses, apartment complexes, schools, nursing
homes, parks; recreation areas and day care centers), as stipulated in the Notice of Residual Petroleum
(attached).
As groundwater contamination exceeds the groundwater quality standards established in Title
15A NCAC 2L .0202 and soil contamination exceeds the residential MSCCs, pursuant to NCGS 14313-
State of North Carolina I Environmental Quality I waste Management
Mooresville Regional Office 1 610 East Center Avenue. Suite 3011 Mooresville, NC 28115
704 6631699

Duke Energy Corporation
May 17, 2017
Page 2 of 2
279.9 and 14313-279.11, you must file the approved Notice of Residual Petroleum (attached) with the
- - Register-of-Deeds.in the county in which the release is located and submita certified copy to the UST
Section within 30 days of receipt of this letter.
As groundwater contamination exceeds the groundwater quality standards established in Title
15A NCAC 2L .0202 and soil contamination exceeds the lower of the soil -to -groundwater or residential
MSCCs, public notice in accordance with 15A NCAC 2L .0409(b) also is required. Thus, within 30 days
of receipt of this letter, a copy of the letter must be provided by certified mail, or by posting in a
prominent place, if certified mail is impractical, to the local health director, the chief administrative
officer of each political jurisdiction in which the contamination occurs, all property owners and occupants
within or contiguous to the area containing contamination, and all property owners and occupants within
or contiguous to the area where the contamination is expected to migrate. Within 60 days of receiving
this letter, this office must be provided with proof of receipt of the copy of the letter or of refusal by the
addressee to accept delivery of the copy of the letter or with a description of the manner in which the
letter was posted. Interested parties may examine the Soil Cleanup Report/ Site Closure Request by
contacting this regional office and may submit comments on the site to the regional office at the address
or telephone number listed below.
This conditional No Further Action determination will not become valid until the UST
Section receives a certified copy of the Notice of Residual Petroleum which is filed with the Register
of Deeds and until public notice requirements are completed.
If you have any questions regarding this notice, please contact me at the address or telephone
number listed below.
Sincerely,
Brad C. Newton, P.G.
Hydrogeologist II
Mooresville Regional Office
UST Section, Division of Waste Management, NCDEQ
Attachments: Notice of Residual Petroleum
cc: Al Quarles — S&ME, Inc. — Charlotte, NC
Gaston County Health Department

LETTER OF TRANSMITTAL RECEIVED
DATE: 5/11/2017 MAY 15 2017 - -
vm -.
TO: Brad Newton
NCDENR, DWM, UST Section NCDEQ MRO UST
610 East Center Avenue, Suite 301
Mooresville, NC 28116
FROM: All Quarles
WE ARE SENDING YOU _X_ Attached _ Under separate cover via _ the following items:
S&ME, INC
9751 Southern Pine Blvd.
Charlotte, NC 28273-5560
Phone:[phone]
Fax:[phone]
_ Shop drawings Prints Plans Samples _Specifications
Copy of letter _X_ Reports NORP
COPIES
DATE
NO.
DESCRIPTION
1
5/11/2017
1
Notice of Residual Petroleum
Duke Energy - Allen Plant Incident Nos. 18137 and 40625
253 Plant Allen Road, Belmont, Gaston County, NC
I
Goo le Earth images indicating NORP area
1
Notice of Residual Petroleum Plat
THESE ARE TRANSMITTED as checked below:
X For approval
For your use
X As requested by the NCDENR
For review and comment
FOR BIDS DUE 20_,
REMARKS:
Newton,
PRINTS RETURNED AFTER LOAN TO US
.ase find the attached Notice of Residual Petroleum for the referenced UST sites. Note that the area of the legal description
included on the attached Plat and Google Earth images (neither to be filed with NORP). Please contact us if you have any
Quarles
COPY TO: Richard E. Powell, Duke Energy (via email)
File
S&ME Project No.: 4335-16-OOIB
Signed:
IF ENCLOSURES ARE NOT AS NOTED, PLEASE NOTIFY US AT ONCE.
This Letter of Transmittal and the documents accompanying this Letter of Transmittal contain information from SWE, Inc., which is confidential and legally privileged.
The information is intended only for use of the individual or entity named on this Letter of Transmittal. If you are not the intended recipient, you are hereby notified that any
disclosure, copying, distribution or the taking of any action in reliance on these documents is strictly prohibited.

NOTICE OF RESIDUAL PETROLEUM
Duke Energy Allen Pant, Gaston County, North Carolina
The property that is the subject of this Notice (hereinafter referred to as the "Site") contains
residual petroleum and is an Underground Storage Tank (UST) incident under North Carolina's
Statutes and Regulations, which consist of N.C.G.S. 143-215.94 and regulations adopted thereunder.
This Notice is part of a remedial action for the Site that has been approved by the Secretary (or
his/her delegate) of the North Carolina Department of Environment Quality (or its successor in
function), as authorized by N.C.G.S. Section 14313-279.9 and 143B-279.11. The North Carolina
Department of Environment Quality shall hereinafter be referred to as "DEQ".
NOTICE
Petroleum product was released and/or discharged at the Site. Petroleum constituents remain on
the site, but are not a danger to public health and the environment, provided that the restrictions
described herein, and any other measures required by DEQ pursuant to N.C.G.S. Sections 143B-
279.9 and 143B-279.11, are strictly complied with. This "Notice of Residual Petroleum" is composed of
a description of the property, the location of the residual petroleum and the land use restrictions on the
Site. The Notice has been approved and notarized by DEQ pursuant to N.C.G.S. Sections 143B-279.9 and
143B-279.11 and has/shall be recorded at the Gaston County Register of Deeds' office
Book , Page
Source Property
Duke Energy Carolinas, LLC (f/k/a Duke Energy Corporation) of Charlotte, North
Carolina is the owner in fee simple of all or a portion of the Site, which is located in the County of
Gaston, State of North Carolina, and is known and legally described as:
Lying and being in the County of Gaston and being located on the property owned by Duke Energy
Carolinas, LLC at the Allen Steam Station and being a portion of the property as described in Deed Book
2681 Page 586 of the Gaston County Register of Deeds and being more particularly described as follows:
Commencing at NGS Monument "ALLEN" bearing NC Grid coordinates of N:529,223.77 and '
E:1,396,421.44 and running with NC Grid NAD 83(2011) bearings and horizontal ground distances the
following six calls: N 82°44' 19"E 3356.93' (Ground) 3356.42' (Grid) with C.G.F. 0.99984554 to a set
spike with cap having N.C. Grid Coordinates NAD 83/2011 of N:529,648.02' and E:1,399,750.94 with
said spike with cap being the Point Of Beginning; thence leaving said Point of Beginning and running
N18007'48"W 926.96' to a set spike with cap; thence N66°33'05"E 586.21' to a set spike with cap; thence
S18017'56"E 1568.76' to a set spike with cap; thence S71°09'37"W 186.93' to a set spike with cap, said
set spike also being located N75°32'35"W 353.03' from existing plant survey monument "ACP 6' ; thence
continuing from set spike N52°21'51"W 713.51' to the Point and Place of Beginning and containing 18.05
acres +/- as shown on plat entitled "Notice of Residual Petroleum Boundary, Plant Allen Steam Station"
as prepared by John P. Scoville 111, PLS L-3343 of ESP Associates, P.A. dated May 3rd, 2017 having ESP
Project No.FP46.800.. ,
For protection of public health and the environment, the following land use restrictions required by
N.C.G.S. Section 143B-279.9(b) shall apply to all of the above -described real property. These restrictions
shall continue in effect as long as residual petroleum remains on the site in excess of unrestricted use
standards and cannot be amended or cancelled unless and until the Gaston County Register of Deed
receives and records the written concurrence of the Secretary (or his/her delegate) of DEQ (or its successor
in function).
Revised January 15, 2013

PERPETUAL LAND USE RESTRICTIONS
Soil: The Site shall be used for industrial/commercial use only. Industriallcommercial use means a use
where exposure to soil contamination is limited in time and does not involve exposure to children
or other sensitive populations such as the elderly or sick. Thereat property shall not be
developed or utilized for residential purposes including but not limited to: primary or secondary
residences (permanent or temporary), schools, daycare centers, nursing homes, playgrounds,
parks, recreation areas and/or picnic areas.
Groundwater: Groundwater from the site is prohibited from use as a water supply. Water supply wells
of any kind shall not be installed or operated on the site.
The above land use restriction(s) shall be enforced by any owner, operator, or other party
responsible for the Site. The above land use restriction(s) may also be enforced by DEQ through any of
the remedies provided by law or by means of a civil action, and may also be enforced by any unit of local
government having jurisdiction over any part of the Site. Any attempt to cancel this Notice without the
approval of DEQ (or its successor in function) shall be subject to enforcement by DEQ to the full extent of
the law. Failure by any party required or authorized to enforce any of the above restriction(s) shall in no
event be deemed a waiver of the right to do so thereafter as to the same violation or as to one occurring
prior or subsequent thereto.
IN WITNESS WHEREOF, Duke Energy Carolinas. LLC has caused this Notice to be executed
pursuant to N.C.G.S. Sections 14313-279.9 and 143B-279.11, this 1 1 day of /y%Gt- i/
2oL7
Duke Energy Carolinas, LLC
By:
(signature)
6M
(tide)
Signatory's name typed or printed: Pat. D I t,�. tbJ8-+
NORTH CAROLINA
W24 COUNTY
cvu5iv \
I, mt`, tG.v! . nde=Z
hereby certify that I
and acknowledged that he is _
and acknowledged, on behalf
foregoing instrument.
a Notary Public for said County and State; do .
personally came before me this day
of Duke Energy Carolinas, LLC
LC, the grantor the due execution of the
WITNESS my hand and official seal, this the ��_ day of /"I67r,4 2017.
FER
`mow C_%fficlal �i�
` Q V,ttllsstp� Q NotaryPub c (sig ature)
My commisolon e
vN AUBUO c)
s % 0,.pt_�9
> 1 ^ 120
Revised January 15, 2013
2

A prov for a purposes of N.C.G.S. 14313-279.11
Ronald Henry Taraban, Regional Supervisor
Mooresville Regional Office
UST Section
Division of Waste Management
Department of Environment and Natural Resources
NORTH CAROLINA
IREDELL COUNTY
I certify that the following person(s) personally appeared before
that he or she signed the foregoing document: Ronald Henry Ta
Date: �
(Official Seal)
day, each acknowledging to me
printed name ofRnional Stoervisor)
Notary Public
Revised January 15, 2013

EXHIBIT "A"
NOTES:
*SURVEYED & MAPPED FOR: DUKE ENERGY CAROLINAS, LLC
•SUBJECT PROPERTY IS NOT WITHIN 2000 FEET OF A
GEODETIC SURVEY MONUMENT.
-&ALL DISTANCES ARE HORIZONTAL GROUND DISTANCES
UNLESS OTHERWISE NOTED.
aAREA BY COORDINATE COMPUTATION.
oPROPERTY SUBJECT TO ANY VALID & ENFORCEABLE
EASEMENTS, RESTRICTIONS & RIGHTS OF WAY OF RECORD.
eSURVEY IS BASED ON PHYSICAL EVIDENCE AND EXISTING
MONUMENTATION FOUND DURING THE SURVEY.
oPROPERTY CORNER PIPE SIZES AS SHOWN ARE NOMINAL
INSIDE DIAMETER.
•BUILDINGS, ROADS, AND FENCES AND OTHER FEATURES
SHOWN ARE TAKEN FROM PLANS PROVIDED BY DUKE
ENERGY WITH AERIAL DATA OBTAINED FROM NC ONEMAP.
•THE PURPOSE OF THIS DRAWING IS TO AID IN THE
DESCRIPTION, DELINEATION, AND BOUNDARY DEFINITION OF
THE AREA FOR A NOTICE OF RESIDUAL PETROLEUM AS
DEFINED ONSITE BY PERSONNEL FROM S&ME AND DUKE
ENERGY AND SURVEYED BY ESP ASSOCIATES,P.A.
PIN
DUKE 59 R177987 FEND%
CORPORATION xSPIKE W/
D.B.2681, PG.586 CAP(S)
NCGS MON."ALLEN"
N.C. GRID
NAD 83/2011
N.529,223.77
E.1.396, 421.44
C.G.F. 0.99984554
m
Q
o
�x
1�1
DTICE OF RESIDUAL
PETROLEUM AREA
1 &05 AC+/— —
SPIKE W/CAP(S)
N.C. GRID NADD 83/2011
N.529,648.02
E.1,399,750.941-
cf )
G A
`_ �oEESSlpy9 9'%
;a SEAL T
DATUM DESCRIPTION
STATE PLANE COORDINATES AS SHOWN WERE
ESTABLISHED BY (VRS) CPS METHOD WITH MULTIPLE
OBSERVATIONS UNDER DIFFERING CONDITIONS, AND
WERE BASED ON NGS MONUMENT (ALLEN),
THE HORIZONTAL DATUM IS NAD 83 (2011).
PROJECT COMBINED GRID FACTOR = .0.99984554
PROJECT COORDINATES ARE LOCALIZED ON MON.
"ALLEN" HAVING STATE PLANE VALUE AS SHOWN
ELSEWHERE HEREON.
VERTICAL DATUM IS BASED ON NAVD 88
SITE: OUZO96
NTS
ESP {M,\-TOIIELMONT
ESP ASSOCIATES,PA
7204 W. FRIENDLY AV.IT
GREENSBORD, NC 27410335-334-7724
FIRM# C-OSB7 I
LEGEND
�A TIE LINES -------
® CONCRETE MONUMENT(F)
PIKE
II CAP(S)
/
(F) FOUND
O Pt POINT NOT SET
O MONUMENT AS DESCRIBED
ix
—ANTS Ii— NOT TO SCALE
N 0
o T'
77
O
NO
� F
7 0
a
£
z
7
t
0
3
.4
O
i
0
6
rn
A �m
Tn
\ L
z z
{ \
\iL
`
®
0 EXISTING PLANT
NJ SURVEY MONUMENT
Y\ACP r
o
Wk �\
PIN #3592779987
DUKE ENERGY p� AhpJl
CORPORATION
D.B.2681, PG.586
�tv I
1' 42 43"W TIE TI M ING PLANT
i 5.9 PLANT BOUNDARY) SURVEY MONUMENT
—X—x—x—X—
STATE PLANE COORDINATES AS
SHOWN WERE ESTABLISHED BY
VRS-RTK CPS METHOD.
I, JOHN P. SCOMLLE, III, CERTIFY THAT UNDER MY DIRECTION AND
SUPERVISION THIS MAP WAS DRAWN FROM AN ACTUAL FIELD SURVEY, THAT
THE BOUNDARIES NOT SURVEYED ARE CLEARLY INDICATED AS DRAWN FROM
INFORMATION FROM DEEDS AS INDICATED, THAT THE RATIO OF PRECISION
AS CALCULATED IS 1:10,000+ AND THAT THIS PLAT WAS PREPARED IN
ACCORDANCE WITH THE STANDARDS AND PRACTICE FOR LAND SURVEYING IN
NORTH CAROLNA AND THIS MAP DOES NOT CREATE A NEW STREET OR
CHANGE AN EXISTING STREET�9N9-ME 'THE ATTACHMENT RULES OF
N.C.C. S. 47-30 PARAGRA�H'(m).
JOHN P. SCOVILLE. III DATE 5/03/2017
FOR SOURCE OF TITLE REFER TO D.B.2681, PG.586
DUKE ENERGY CAROLINAS, LLC
NOTICE OF RESIDUAL PETROLEUM BOUNDARY
PREPARED FOR S&ME AND DUKE ENERGY
PLANT ALLEN STEAM STATION
SOUTHPOINT TOWNSHIP GASTON COUNTY, N.C.
BOOK: FP46.800 200 0 200 400 600 CREW:CRM
DATE:05/03/17 DRAWN BY:MED
SCALE: 1"= 400' SCALE IN FEET R.O.P.= 1:10,000+
LAND UNIT: 0000000 1 MAP: 4335-16-0018
400 S. TRYON STREET
PO BOX 1007
CHARLOTTE N.C. 28201-1007
TELEPHONE NO. (7D4) 382-2361

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

�n

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

w
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
Allen Steam Station
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
The North Carolina Department of Environmental Quality's (DEQ) Division of Water Resources
(DWR) has reviewed Duke Energy's calculated revised provisional background threshold values
(PBTVs) for soil and groundwater for the subject facility. DWR reviewed the calculated PBTVs based
on background data provided in the revised Comprehensive Site Assessment (January 2018), using the
Revised Statistical Methods for Developing Reference Background Concentrations for Groundwater
and Soil at Coal Ash Facilities dated May 26, 2017 and additional guidance provided in the December
7, 2017 email from Steve Lanter to Ed Sullivan and John Toepfer. DWR hereby approves all accepted
PBTVs for groundwater and soil as outlined in the attached tables. These accepted PBTVs shall
become the Background Threshold Values (BTVs) for the facility and will serve as a basis for the
proposed remedial alternatives in the upcoming Corrective Action Plans.
Per 15A NCAC 02L .0202(b)(3), where naturally occurring substances exceed the established
groundwater standard, the standard shall be the naturally occurring concentration as determined by the
Director. Therefore, BTVs calculated above the groundwater standards or Interim Maximum
Allowable Concentrations (IMACs) in accordance with the provisions in 15A NCAC 02L .0202 and
accepted by DWR, shall become the enforceable groundwater standard. Otherwise, the enforceable
groundwater, standards shall be those listed under 15A NCAC 02L .0202(h) including any effective
IMACs.
For soils, PBTVs that are calculated above the DEQ Division of Waste Management Inactive
Hazardous Sites Branch's (IHSB) Preliminary Soil Remediation Goals (PSRG) for the protection of
groundwater shall become the BTVs for use in developing an appropriate corrective action strategy.
For compounds that do not have an established PSRG, but do have a groundwater standard (i.e. chloride
and sulfate) pursuant to 15A NCAC 02L .0202, use the calculation provided in the PSRG table to
establish a PSRG if the required site -specific data are available. The PSRG table can found under the
IHSB website at: https://dgg.nc.gov/about/divisions/waste-management/gMerf md-section/inactive-
hazardous -sites -program.
----'—Nothing Compares: -k,
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 Brandy Costner (Mooresville Regional Office) at (704) 663-
1699 or Steve Lanter (Central Office) at [phone].
Sincerely,
LiU-,--
da Culpepper, Director
Division of Water Resources
Attachments
cc: MRO WQROS Regional Office Supervisor
WQROS Central File Copy

Allen Steam Station - Groundwater Background Threshold Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy Calculated PBTVs from
Flow Unit
15A NCAC
02L Standard
or IMAC
DWR Concurrence (Acceptable/Not Acceptable)
MRO Comments
Flow Unit
Shallow
Deep
Bedrock
Shallow
Deep
Bedrock
H
S.U.
4.4-7.4
6.2-7.5
7.2-8.4
6.5-8.5
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Alkalimly
mg/L
105
77
116
NE
Ac" ;table
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Aluminum
0.
534
304
301
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Antimony
µg/L
0.756
0.5
0.5
1
Acceptable
Acceptable
Acceptable
Shallow - removed 1.4 as outlier Gatm m UTL=1.08; Remove BG-2BRA2 from dataset. Agreed upon value that differs from
originally pro osed value by Duke EneW.
Arsearr
g/L
0.586
1
1.6
10
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Barium
µg/L
105
131.6
21
700
Aei�etahlc
Accc table
Acceptable
Remove BG-2BRA2 from dataset
Bervlkitan
PVL
0.124
0.0286
0.1
4
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Bicarbonate
m /L
105
773
116
NE
Aare table
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Borten
50
50
50
700
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Cadmium
' • I.
1
1
0.09
2
Acee table
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Calcium
mg'L
20.4
17.4
24.7
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Carbonate
mg/L
5
5
5
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Chloride
mg/L
4.5
5.2
4.9
250
Aece tahke
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Chromiurn(V1)
t
2.24
13
0.66
NA
Acceptable
Acceptable
Not Acceptable
Remove BG-2BRA2from dataset:Max=0.23
Chromium
tg L
6.79
6.8
8.9
10
Acee table
Acceptable
Not Acceptable
Remove BG-2BRA2 from dataset; Max=5.6
Cobalt
WL
1.52
0.502
0.3
1
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Copper
µg/L
2.85
2.72
1.6
1,000
Acceptable
Acceptable
Acceptable
Deep - removed 3.3 as outlier Gamma UTIr2.39; Remove BG-2BRA2 from dataset Agreed upon value that differs from
orieinallti proposed value by Duke Energy,
Iron
t,•2
884
356
284
300
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Lead
t t t.
0.214
0.1
0.17
15
Acce table
Acceptable table
Acceptable
Remove BG-2BRA2 from dataset
Magnesium
mg L
5.67
5.11
8.13
NE
Accevtblc
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Manganese
7,
225
26.2
j 278
50
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Merrury
t /l,
0.2
0.2
0.2
1
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Methane
12
10
89.6
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Molvbdenum
t +1.
0.844
1.8
8.9
NE
Acceptable
Acceptable
ce Actable
Remove BG-2BRA2 from dataset
Nickel
t 4,
5.78
5.03
4.6
100
Acceptable
Acceptable
Not Acceptable
Remove BG-2BRA2 from dataset:; Max=3.4
Nitrate + Nitrite
me-N/L
0.835
0.96
1.7
11*
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2fromdataset
Potassium
mgL
5.67
5.05
7.92
NE
Acceptable
Acce table
Acceptable
Remove BG-2BRA2 from dataset
Selenium
Z
0.5
0.62
OS
20
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Sodium
mn L
20.6
12
11.9
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Strontitun
fig-1
298
232
181
NE
Accopiabic
Acceptable
Not Acceptable
Remove BG-2BRA2 from dataset:: Max=154
Sulfate
m t.
1.5
5.4
73
250
Acceptable
Acceptable
Not Acceptable
Remove BG-2BRA2 from datasel. Max-2.9
Sulfide
m - L
0.1
0.1
0.1
NE
Acecrtable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
TDS
m • L
163
158
165
500
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Thal I ium
m :1.
0.1
0.1
0.1
0.2
Acc tablt
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
TOC
'l
1
1
5.6
NE
Acce table
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Vanadium
m *'I..
5.67
11.5
15.9
0.3
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Zinc
t L
45.3
10
15.3
1,000
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Radium C1nlall
C L
1.41
1.06
1.1
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
Uranium [ Iota11
is mL
0.0005
0.000469
0.0009
NE
Acceptable
Acceptable
Acceptable
Remove BG-2BRA2 from dataset
NA - Not Applicable
ND - Not Detected
NE - Not Established
mg/L - milligrams per liter
pCi/L - picocuries per liter
Radium (Total) - Radium-226 and Radium-228 combined
*The 15A NCAC 02L Standard is 10 mg/L for Nitrate and I mg/L for Nitrite (added for a total of 11 mg/L)
S.U. - Standard Unit Note: Bedrock dataset Is still Insufficient and defaults to max concentration.
TOC - Total Organic Carbon
TDS - Total Dissolved Solids
µg/mL - micrograms per milliliter
µg/L - micrograms per liter
Uranium (Total) - Uranimn-233, Uranium-234, Uranium-236, and Uranium-238 combined
Page 1 of 2

Allen Steam Station - Soil Background Threshold
Values (May 14, 2018)
Parameter
Reporting
Units
Duke Energy
Calculated PBTVs
from CSA Report
(January 31, 2018)
PSRG Protection
of Groundwater
(October 2017)
DWR Concurrence
(Acceptable/Not
Acceptable)
MRO Comments
pH
S.U.
4.4-6.2
NA
Acceptable
NA
Aluminum
mg/kg
44,683
110000
Acceptable
NA
Antimony
mg/kg
0.61
0.9
Acceptable
NA
Arsenic
mg/kg
2.391
5.8
Acceptable
NA
Barium
mg/kg
384
580
Acceptable
NA
Beryllium
mg/kg
1.31
63
Acceptable
NA
Boron
mg/kg
6.8
45
Acceptable
NA
Cadmium
mg/kg
0.038
3
Acceptable
NA
Calcium
mg/kg
630
NE
Acceptable
NA
Chloride
mg/kg
14
NE*
Acceptable
NA
Chromium
mg/kg
56.9
3.8
Acceptable
NA
Cobalt
mg/kg
29.2
0.9
Acceptable
NA
Copper
mg/kg
71.3
700
Acceptable
NA
Iron
mg/kg
61,162
150
Acceptable
NA
Lead
mg/kg
13.5
270
Acceptable
NA
Magnesium
mg/kg
10,584
NE
Acceptable
NA
Manganese
mg/kg
1,222
65
Acceptable
NA
Mercury
mg/kg
0.11
1
Acceptable
NA
Molybdenum
mg/kg
5.4
7.1
Acceptable
NA
Nickel
mg/kg
9.87
130
Acceptable
NA
Nitrate (as N)
mg/kg
0.3
NE
Acc table
NA
Potassium
mg/kg
10,698
NE
Acceptable
NA
Selenium
mg/kg
0.812
2.1
Acceptable
NA
Sodium
mg/kg
600
NE
Acceptable
NA
Strontium
mg/kg
31
NE
Acceptable
NA
Sulfate
mg/kg
14
NE*
Acceptable
NA
Thallium
mg/kg
0.482
0.28
Acceptable
NA
Vanadium
mg/kg
132
350
Acceptable
NA
Zinc
mg/kg
72.3
1200 A
Acceptable
NA
*Constituent has 2L Standard or IMAC. Use k!alsutat ioii in the PSRG table to determine value.
NA - Not applicable
ND - Non -Detect
NE - Not Established
mg/kg - milligrams per kilogram
S.U. - Standard Unit
Page 2 of 2

Water Resources
Enviromnental Quality
June 11, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: 2018 Comprehensive Site Assessment Update Comments
Allen Steam Station
Dear Mr. Draovitch:
ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
LINDA CULPEPPER
Interim Director
On January 31, 2018, the North Carolina Department of Environmental Quality's (DEQ's) Division of
Water Resources (DWR) received the Comprehensive Site Assessment (CSA) Update for the subject
facility. Based on the review conducted to date, the DWR has concluded that sufficient information
has been provided in the report to allow preparation of the Corrective Action Plan (CAP); however,
there are data gaps that must be addressed prior to, or in conjunction with, preparation of an approvable
CAP.
As described in the attached itemized list of CSA Update comments (Attachment 1), additional data
and/or data analysis will be needed to address data gaps, complete evaluation of exposure pathways,
predict time and direction of contaminant transport, and ultimately refine remedial design. The
assessment of all primary and secondary source areas (including, but not limited to, impoundments,
cinder storage areas, coal piles, and contaminated soils) must be included in the CAP, or in a CAP
amendment. The DWR expects that information collected regarding the source areas will be used to
formulate the CAP recommendations. For source areas where this may not be possible or areas where
pollutants may be hydraulically isolated, please contact me to discuss.
In an email dated April 18, 2018, Duke Energy proposed a CAP submittal date of October 31, 2018.
However, as you are aware, Duke Energy and the DEQ are currently discussing revisions to the CAP
deadlines and the final revised date for CAP submittal will be communicated to Duke Energy in a
separate correspondence.
An overview of CSA Update data gaps includes the following:
• The report contents are often presented in a data summary format, exhibiting a lack of
conclusive data analysis and interpretation of site conditions.
• The report fails to fully integrate and evaluate data collected from previous versions of the
CSA reports for the facility.
-�`->"Nothing Compares!_ k ,
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 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 delineate exceedances of the
15A NCAC 2L or 2B standards above background levels.
• The characterization of other primary and secondary sources other than impoundments that
contribute to the groundwater plumes is inadequate.
• As detailed more fully in the attached document, additional data gaps remain concerning
impacts from coal ash at the facility.
The data gaps related to the site assessment at the facility, including those related to primary and
secondary sources other than impoundments, may limit the cleanup remedy and site management
strategies for a source area. The lack of a well -documented interpretation of the existing data, or
missing data that the DEQ believes will be necessary to support proposed corrective action, may limit
DEQ's ability to approve certain corrective action measures [e.g. 15A NCAC 02L .0106(1)]. For
example, monitored natural attenuation cannot be approved for source areas where surface water
samples have not been collected (but could be collected) and that demonstrate the groundwater
discharge does not result in exceedances of 15A NCAC 02B .0200 regulatory standards.
Please refer to the letter to Duke Energy dated May 14, 2018, for approved background threshold
values developed for the facility as part of the CSA Update.
Duke Energy should contact the Mooresville Regional Office to initiate the scheduling of a meeting
between DWR and Duke Energy's technical staff (including contractors) to discuss data gaps in greater
detail. Promoting regular dialogue in a small group format assists in addressing questions and
problems that may come up during the development of the CAP, and better ensures that Duke Energy
is meeting DWR's expectations.
If you have any questions, please feel free to contact me at [phone]. Please contact Brandy
Costner (Mooresville Regional Office) at [phone] to discuss any additional questions regarding
the CSA Update data gaps in more detail.
Sincerely,
Jon 'aard, Section Chief
Divi ion of Water Resources
Attachment: Allen Steam Station CSA Update Comments
cc: MRO WQROS Regional Office Supervisor
WQROS Central File Copy

Allen Steam Station
Condensed Comments for Comprehensive Site Assessment Update Report
Submitted January 31, 2018
Delineation of Groundwater Contamination
Horizontal and vertical delineation of groundwater impacts has not been completed at Allen Steam
Station, which is a requirement of the Coal Ash Management Act (CAMA) and 15A NCAC 02L .0106.
The Corrective Action Plan (CAP) shall include updated maps and adequate data interpretation/evaluation
that address the following:
• The report suggests there are inadequate data in the shallow flow layer beneath both the inactive
and active ash basins. This data gap was not identified as such in the report; however, this lack of
information concerning site conditions beneath the basins should be addressed accordingly in
order to complete characterization and support CAP development.
• Rationale for why radionuclides are not considered as COIs at Allen Steam Station should be
provided.
• Based on review of the isoconcentration maps (Figures 11-1 thru 11-60), it is apparent that
additional characterization of the vertical and horizontal extent of several COIs at several
GWA/CCR well pair locations is warranted (This issue can be discussed in greater detail between
North Carolina Department of Environmental Quality (NCDEQ) Mooresville Regional Office
(MRO) and Duke Energy staff prior to completing the CAP).
• The MRO does not support the use of BG-2BRA2 as a background well at this time due to
unacceptable groundwater quality. Once data are available that indicates water quality is
acceptable at this location (whether it be additional well development or replacement), MRO will
consider adding this location into the background evaluation.
• The report stated, "Available groundwater data from monitoring wells associated with the
Federal Coal Combustion Residuals Rule (CCR Rule) compliance program are also considered
in data interpretations. However, the CCR data has not been fully incorporated into the analysis
of this CSA due to the data only becoming available as of mid- January 2018. For example,
analytical results from CCR Rule -specific monitoring wells are included on isoconcentration
maps and analytical summary tables, but not integrated into detailed mathematical analysis, such
as piper plots, box -and -whisker plots or background statistical calculations. ". While it is
accurate that the Coal Combustion Residuals (CCR) data collected as part of the Federal CCR
Rule were not publicly available until mid -January 2018, the data were available to Duke Energy
and their consultants as it was collected between 2016 to the present. CCR data could have and
should have been utilized to the fullest extent in this report, but it is unclear as to what extent
CCR data were utilized and incorporated into evaluations of site conditions, if at all. CCR
groundwater data are expected to be fully incorporated into the CAP.
Groundwater Flow, Contaminant Flow and Transport
Additional information related to groundwater flow and the mechanisms affecting contaminant migration
is necessary. Comments include, but are not limited to the following:
• According to the report, private WSW data collected after 2015 was only preliminarily reviewed.
A more detailed review of WSW data post 2015 is warranted. This review is necessary to ensure
the additional WSWs sampled since 2015 at Allen Steam Station do not exhibit impacts from coal
Page 1 of 4

ash activities from the site and support Duke Energy's position that private WSWs have not been
impacted.
• It was stated in the report that boron and sulfate values should be considered with caution due to
grout contamination likely caused by poor well construction. During review of this report, it was
noticed that data collected from the select wells that continue to exhibit high pH or turbidity were
not presented or included in the evaluations as they were deemed invalid. This is contrary to
what was agreed upon between MRO, Duke Energy and their consultants in a meeting on June
15, 2017. In order to reach a compromise regarding well replacements due to grout contaminated
wells, MRO, Duke Energy and their consultants agreed that boron and sulfate were seemingly
unaffected by elevated pH and/or turbidity and these suspect wells would be used for water -level
measurements along with boron and sulfate sampling that would support development of fate and
transport models with respect to leading -edge constituents. If Duke Energy and their consultants
do not support use of these data to address this critical component of the site assessment, then the
wells should be replaced and quality data collected to support characterization of groundwater
contamination.
• Upward gradients were also observed west of the ash basins in close proximity to private WSWs
(Figures 6-13 thru 6-15). An evaluation of the upward gradients observed should be provided and
should also include discussion of the relevance in terms of contaminant movement.
• The report suggests upward gradients inhibit downward migration of contaminants into bedrock;
however, site data at several locations at Allen Steam Station indicate contamination is already
present in bedrock, particularly east of the basins adjacent the Catawba River. Please provide
adequate rationale based on site -specific data to support an interpretation of site conditions where
upward gradients inhibit vertical contaminant migration across the facility.
• There is conflicting information presented in this report regarding the presence of a topographic
divide located approximately along NC Highway 273 that is considered to be a groundwater
divide. The groundwater flow direction depicted in Figure ES. 1 does not support this statement
based on groundwater flow direction arrows. Presence or absence of this
topographic/groundwater divide should be further evaluated and supported by data.
• Concentration trends were depicted as graphs in Figures 14-81 through 14-101 with footnotes that
stated the most recent data available from March 2010 to November 2017 were utilized. While
these figures do illustrate temporal ranges of COI concentrations, there is no
discussion/evaluation provided within the report as to how these data relate to plume status or
how hydrogeological and/or geochemical factors affect COI distribution across the site. For
example, total and hexavalent chromium are shown to have increasing concentrations upgradient
of the ash basins (western portion of the site), but no explanation was provided to support
interpretation of site conditions. Provide an explanation of the spatial and temporal patterns of
groundwater contamination with respect to each COI across the site where applicable.
• It is stated in multiple sections of the report that the majority of ash in both basins is saturated.
The alternatives analysis for source control provided in the CAP and Closure Plans should
provide an evaluation of site conditions that incorporate the volume of ash, the impact of
decanting/dewatering, and the volume of ash that is anticipated to remain saturated under a Cap-
in -place scenario. The CAP and Closure Plan should explain how the lateral component of
groundwater flow and resulting contaminant flux will be addressed if source material remains in
place, including an evaluation of potential groundwater control measures that could be
implemented to lower the water table.
Page 2 of 4

Other Potential Primary and Secondary Sources
As previously discussed, other primary and secondary sources must be assessed in regard to groundwater
impacts. Sources contributing to groundwater contamination associated with the impoundments
(comingled) must be assessed and results presented as well as 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 comingled with areas impacted by the impoundments may be assessed
separately in accordance with a schedule approved by the Department. Additional information needed
includes, but is not limited to the following:
Based on review of Figure 7-1 and 14-102, delineation of soil impacts has not been completed at
Allen Steam Station. Soil contamination should be delineated to either the site -specific
background threshold values (BTVs) or Protection of Groundwater (POG) Preliminary Soil
Remediation Goals (PSRGs), whichever is higher. Where appropriate, use the equation provided
in the PSRG table to establish a POG PSRG-for a constituent with 02L standard that does have a
PSRG established.
Provide an explanation of how and why soil contamination occurs outside of the waste
boundaries, particularly soils which exhibit elevated concentrations of chromium, iron,
manganese, strontium, and vanadium upgradient of the ash basins.
Groundwater data suggests the coal pile is contributing to groundwater impacts at the site. The
coal pile is located north of the RAB Landfill (aka inactive ash basin). Further assessment is
warranted in this area to understand contributions of groundwater impacts from the coal pile and
provide delineation on this portion of the site. Duke Energy has already provided a work plan to
assess the coal pile area. This evaluation should be included in the CAP.
2L-2B Surface Water Sampling
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:
Duke Energy recognizes the need for additional surface water samples and submitted a proposal
to conduct 2L-2B compliance sampling at the facility. To date, only grab surface water samples
have been collected at the facility, which is not in compliance with 02B for calculating acute and
chronic values for select constituents. 2L-2B sampling is necessary to assess the leading edge of
the contaminant plume to allow for a better understanding of groundwater discharge to surface
waters. Also, it has a direct bearing on remedial technologies available for use at the site. If 21-
2B compliance cannot be adequately demonstrated then MNA may not be considered a viable
option as a remedial technology.
Maps, Figures, and Tables
Revised and/or additional tables, maps and figures are necessary to better represent an understanding by
Duke Energy 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 the following:
• Vertical gradient maps (figures 6-13 thru 6-15): Evaluation of upward gradients observed at the
site in respect to contaminant movement should be discussed.
• Isoconcentration maps (figures 11-1 thru 11-60):
Page 3 of 4

o ALL data points should be included on figures regardless of validity of data.
Maps/figures are visual representations of data, but when data is left off it can be
misleading and result in forming inappropriate conclusions. Notes should be added
regarding data validity and an explanation of why better -quality data is needed to provide
a more accurate assessment of actual site conditions.
o The maps indicated that data collected between March 2010 and November 2017. It
should be indicated on the map for each data point which sampling event the data is from
so that can be factored into the review/evaluation of data provided on the maps. If the
majority of the data is from the November 2017 sampling event and a small subset is
from other sampling events, simply state that in the legend and then on the map next to
the locations that differ put the date of the sampling event the data was obtained.
o Reporting limits should be utilized instead of ND (non -detect). This provides meaningful
information.
0 2L/IMAC concentration lines should have been included on the maps regardless of the
BTV.
o There were instances where isoconcentration lines were not provided because it was
deemed attributable to background. This is misleading - the map should be representative
of available site data and then any evaluation/interpretation of that data should be
included in the report itself.
• Table 11-2 was provided to show wells that have transducers deployed in association with the
coal pile holding basin dewatering project. These transducers are collecting valuable data on this
portion of the site. Data collected as part of this project was not discussed or utilized in
evaluations in this report. This data and related evaluation shall be included in the CAP.
Modelling
Models are useful tools in understanding groundwater flow, contaminant transport and factors that hinder
or facilitate contaminant migration. Models also aid in the evaluation of corrective action technologies
and choosing the most effective technologies. Comments include, but are not limited to the following:
• Models were run out to 100 years in the previous models submitted, with compliance not
achieved for several constituents within that timeframe. It would be more appropriate to let the
model run for 200-year and 300-year timeframes, or until compliance is achieved, so more
informed decisions could be made about determining what a technically feasible timeframe is
concerning remediation, particularly with regard to metals.
• It was indicated in the report that models would only include data up to 4' quarter 2017. The
MRO expects 2018 data and any other applicable future data collected to be incorporated into
updated models and submitted to support evaluation of remedial alternatives.
• Initial models did not account for off -site water supply wells (WSWs). Even though, MRO has
not reviewed any revised models, it is MRO's understanding that off -site WSWs have been added
to the models. The MRO would like to emphasize the importance of this for the updated models
as well as the fact that there are at least 3 large capacity wells located in close proximity of the
facility. These wells produce on average over 4,000 gallons per day and this should be accounted
for in the models.
• All COIs should be modeled unless rationale for why they should not be included is provided to
the Department.
• The MRO would like to reiterate any direction given by Bill Deutsch (the NCDEQ Geochemical
Advisor) is expected to be incorporated into the geochemical models.
Page 4 of 4

November 13, 2018
Paul Draovitch
Senior Vice President
Environmental, Health & Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, North Carolina 28202
Subject: Final Classification of the Two Coal Combustion Residuals Surface
Impoundments located at Duke Energy's Allen Steam Station, Gaston 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 two coal
combustion residuals surface impoundments, called the Inactive Ash Basin (or the Retired Ash
Basin) and Active Ash Basin, located at Duke Energy's Allen Steam Station in Gaston County,
NC. NCDEQ makes the following specific findings:
1. Duke Energy has established permanent water supplies as required for the above
referenced impoundments pursuant to N.C. Gen. Stat § 130A-309.21 l(cl). See Exhibit 1
(Duke Energy Alternate Water Supply Submittal), Exhibit 2 (Alternate Water Supply
Supplemental Documents), and Exhibit 3 (NCDEQ Alternate Water Supply Approval);
and
2. Duke Energy has rectified any deficiencies identified by, and otherwise complied with
the requirements of, any dam safety order issued by the Environmental Management
Commission for the above referenced impoundments pursuant to N.C. Gen. Stat. § 143-
215.32. Specifically, NCDEQ has verified through inspection that Duke Energy has
rectified all deficiencies identified by Dam Safety Order 16-01 (issued on August 22,
2016) at Duke Energy's Allen Steam Station. See Exhibit 4 (Dam Safety Order 16-01),
Exhibit 5 (Dam Inspection Report), Exhibit 6 (October 3, 2018 DEMLR Letter Regarding
Dam Safety Order 16-01 Compliance Status), and Exhibit 7 (October 10, 2018 EMC
Meeting Minutes).
D_EQ��
North Carolina Department of Environmental Quality
217 West Jones Street 1 1601 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 two coal combustion residuals surface impoundments, called the Inactive
Ash Basin and Active Ash Basin, at Duke Energy's Allen Steam Station as low -risk.
If you have any questions about NCDEQ's determinations provided in this letter, please contact
me at [phone].
Sincerely,
as" 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
rH D.F �
.w/niwaiM P1111 �w - Oro
North Carolina Department of Environmental Quality
217 West Jones Street 1 1601 Mail Service Center I Raleigh. North Carolina 27699-1601
919.707.8600

Anchor QEA of North Carolina, PLLC ANCHOR
231 Haywood Street
Asheville, North Carolina 28801 kz QEA
828.281.3350
Transmittal
To: Mr. Brad C. Newton, PG
DEQ UST Section
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Cc: Rick Powell, PG, Duke Energy Carolinas, LLC
Re: December 2018 Free Product Recovery Report
Copies Description
January 29, 2019
From: Alec Macbeth
Project Number: C81290-27.01
1 December 2018 Free Product Recovery Report
Report Date: January 29, 2019
UST Incident Name: DUKE POWER - ALLEN PLANT
UST Incident Number: 11186
Facility ID: 00-0-0000034085
UST Number: MO-3926
Alexander Macbeth, PG, Professional Geologist
\\ashevillel\asheville\Projects\Duke Energy\Allen Steam Station\Fuel Oil Light -Off UST\2019-01 Report\Final Report\DEQ Transmittal\Trans-Newton-Groundwater Monitoring
Rpt-January 2019.docx

January 2019
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank
Incident No. 11186
ti9
kzANCHOR
QEA
December 2018 Free Product Recovery Report
Prepared for Duke Energy Carolinas, LLC

January 2019
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank
Incident No. 11186
December 2018 Free Product Recovery Report
Prepared for Prepared by
Duke Energy Carolinas, LLC Anchor QEA of North Carolina, PLLC
526 South Church Street 231 Haywood Street
Mail Code EC13K Asheville, North Carolina 28801
Charlotte, North Carolina 28202
Project Number: C81290-15.01
\\ashevillel\asheville\Projects\Duke Energy\Allen Steam Station\Fuel Oil Light -Off UST\2019-01 Report\Final Report\2019_01_Free Product Recovery
Report -Allen Steam Station -incident 11186_2019-01-29.docx

TABLE OF CONTENTS
Site Information
Certification Page
iv
v
1 Introduction................................................................................................................................1
1.1 Background and Remedial Action to Date................................................................................................1
1.1.1 Historical Remedial Action...............................................................................................................2
1.1.2 Historical Assessment........................................................................................................................2
1.2 Receptors................................................................................................................................................................4
1.3 Risk Classification and Cleanup Goals.........................................................................................................4
2 Well Gauging..............................................................................................................................5
2.1 Recovery Well Measurements........................................................................................................................5
2.2 Monitoring Well Measurements....................................................................................................................6
3 Results and Discussion.............................................................................................................7
3.1 Free Product Recovery......................................................................................................................................7
3.2 Water Level Gauging..........................................................................................................................................7
4 Conclusions and Recommendations.....................................................................................8
4.1 Summary and Conclusions..............................................................................................................................8
4.2 Recommendations..............................................................................................................................................8
5 References.................................................................................................................................10
TABLES
Table 1 Monitoring and Recovery Well Construction Information
Table 2 Free Product Recovery Information and Cumulative Volume Recovered
Table 3 Current and Historical Groundwater Elevations
FIGURES
Figure 1 Site Location Map
Figure 2 Site Layout Map
Figure 3 Recovery and Monitoring Well Locations Map
Figure 4 Free Product Thickness Map — December 2018
December 2018 Free Product Recovery Report i January 2019

Figure 5 Water Level Elevations — December 2018
Figure 6 Free Product Thickness Trend: June 1994 to April 1996
Figure 7 Free Product Thickness Trend: July 1996 to December 2018
Figure 8 Free Product Recovery Trend: 1994 to December 2018
APPENDIX
Appendix A Well Gauging Log
December 2018 Free Product Recovery Report ii January 2019

ABBREVIATIONS
Anchor QEA
Anchor QEA of North Carolina, PLLC
213 standard
Title 15A, North Carolina Administrative Code, Subchapter 213
2L standard
Title 15A, North Carolina Administrative Code, Subchapter 2L
COC
constituent of concern
DEQ
North Carolina Department of Environmental Quality
Duke Energy
Duke Energy Carolinas, LLC
EPH
extractable petroleum hydrocarbons
GCL
gross contamination levels for groundwater
MDL
method detection limit
NRP
Notice of Residual Petroleum
Site
Allen Steam Station No. 2
SVE
soil vapor extraction
SVOC
semivolatile organic compound
TOC
top of casing
UST
underground storage tank
VOC
volatile organic compound
VPH
volatile petroleum hydrocarbons
December 2018 Free Product Recovery Report iii January 2019

Site Information
Date of Report:
January 2019
Facility ID:
0-034085
Incident Number:
11186
UST Number:
MO-3926
Site Risk/Rank:
Intermediate
Land Use:
Industrial
Site Name:
Duke Energy Allen Steam Station Fuel Oil Light -Off UST
(Incident No. 11186)
Site Street Address:
253 Plant Allen Road
City:
Belmont, North Carolina
Latitude:
35.190243'
Longitude:
-81.0084760
Property Owner:
Duke Energy Carolinas, LLC
Property Operator:
Duke Energy Carolinas, LLC
Consultant:
Anchor QEA of North Carolina, PLLC
231 Haywood Street
Asheville, North Carolina 28801
Date Release Discovered:
March 24, 1993
Estimated Quantity of Release:
Unknown
Cause of Release:
Failure of a recirculation pipe associated with the boiler
underground storage tank (UST) system
Source of Release:
Former fuel/product lines
Content of Release:
No. 2 fuel oil
December 2018 Free Product Recovery Report iv January 2019

Certification Page
I, Alexander Macbeth, PG, a Licensed Geologist for Anchor QEA of North Carolina, PLLC, do certify
that the information contained in this report is correct and accurate to the best of my knowledge.
OLO
Anchor QEA of North Carolina, PLLC, is licensed to practice geology/engineering in North Carolina.
The certification numbers of the company are P-1649 (engineering) and C-540 (geology).
December 2018 Free Product Recovery Report v January 2019

Introduction
On behalf of Duke Energy Carolinas, LLC (Duke Energy), Anchor QEA of North Carolina, PLLC
(Anchor QEA), has prepared this free product recovery report for the Duke Energy Allen Steam
Station Fuel Oil Light -Off Underground Storage Tank (UST; Incident No. 11186). This report presents
free product recovery and water level gauging data collected at the Site on December 18, 2018. The
Allen Steam Station is located at 253 Plant Allen Road in Belmont, Gaston County, North Carolina. A
Site Location Map is included as Figure 1. A Site Layout Map is included as Figure 2.
Current and historical data indicate that, excluding a small amount of free product intermittently
detected in certain recovery wells, the Site risk classification would be low, and the Site would be
eligible for closure with a Notice of Residual Petroleum (NRP) designation recorded at the
Gaston County Register of Deeds. Anchor QEA understands that an NRP is currently on file with the
Gaston County Register of Deeds (Deed Book 4913, pages 1160 through 1162) that was prepared for
a separate UST Incident and includes the Site area. The NRP includes land use restrictions that restrict
the Site property to industrial/commercial use only and restrict the use of groundwater. Groundwater
cannot be used as a water supply.
To efficiently address any potential remaining free product, Anchor QEA provided the following
recommendations in the 2018 Groundwater Monitoring Report (Anchor QEA 2018):
• Continue free product level gauging and recovery using oil -absorbent socks, as warranted.
• Suspend groundwater sample collection in Site monitoring and recovery wells, based on
approximately 24 years of historical groundwater data and the lack of detections of
constituents of concern (COCs) or exceedances of gross contamination levels for groundwater
(GCL; DENR 2013) or 2B standards' multiplied by a factor of 10 in Site monitoring wells
(MW-1, MW-2, and MW-10) and recovery wells (RW-2R, RW-3, RW-4, RW-5, and RW-6).
• Decommission the pump -and -treat system.
The North Carolina Department of Environmental Quality (DEQ) approved these recommendations in
August 2018 (DEQ 2018). This report documents the first two recommendations in the preceding
bulleted list. The pump -and -treat decommissioning report will be submitted under separate cover.
1.1 Background and Remedial Action to Date
A historical release of No. 2 fuel oil was discovered at the Site on March 24, 1993. This release
stemmed from a failure in a recirculation pipe associated with a 27,000-gallon-capacity light -off fuel
oil UST system servicing the plant boilers. The UST has been closed in place, and the volume of the
' Surface water standards, as defined in Title 15A, North Carolina Administrative Code, Subchapter 213.0202
December 2018 Free Product Recovery Report 1 January 2019

release is unknown. The release is identified as Duke Energy Allen Steam Station Fuel Oil Light -Off
UST (Incident No. 11186).
1. 7. 7 Historical Remedial Action
Prior to July 1996, free product recovery pumps and hand -bailing methods were used to recover the
No. 2 fuel oil from the subsurface as it accumulated in groundwater monitoring and recovery wells.
In July 1996, a total -fluids pump -and -treat groundwater system began operation. The pump -and -
treat system consisted of six product recovery wells (RW-1, RW-2, RW-3, RW-4, RW-5, and RW-6).
Per DEQ correspondence dated September 18, 2015, the pump -and -treat system was deactivated on
October 7, 2015. The pump -and -treat system was subsequently restarted on March 9, 2016 (per DEQ
correspondence), and operated with recovery wells RW-2R, RW-4, and RW-5. Per a May 1, 2017
meeting between DEQ and Duke Energy, the pump -and -treat system was shut down on May 3, 2017,
due to minimal free product recovery for several years prior to that date (S&ME 2017a). The system
remains deactivated at present. In June and July 2017, free product removal activities were
transitioned to passive recovery using oil -absorbent socks deployed in Site recovery wells.
A soil vapor extraction (SVE) system was installed on April 9, 1997, in the area of monitoring wells
MW-3 and MW-4. COC concentrations have remained below 2L standards' in these wells since 2001.
The SVE system was turned off in approximately 2006 because groundwater COC concentrations
remained below 2L standards and because of construction activities associated with flue -gas
desulfurization. SVE well SVW-1 was abandoned in May 2006.
7. 7.2 Historical Assessment
The historical monitoring and recovery well network has consisted of 11 groundwater monitoring
wells and six recovery wells. Historically, No. 2 fuel oil was detected in all six product recovery wells
on the Site (RW-1, RW-2, RW-3, RW-4, RW-5, and RW-6). Several Site monitoring and recovery wells
have been destroyed or abandoned due to construction activities or because the wells were no
longer needed for groundwater monitoring or No. 2 fuel oil recovery.
Recovery wells RW-1 and RW-2 were abandoned in 2009. Recovery well RW-2 was replaced with
RW-2R in 2010, and recovery well RW-3 was redeveloped in 2010 under Recovery Well Construction
Permit No. WR0300091.
Semiannual groundwater monitoring and reporting had been performed through January 2017, at
which point the monitoring frequency was modified. The January 2017 groundwater sampling results
from monitoring wells MW-1 and MW-2 indicated no detections of volatile organic compounds
(VOCs) or semivolatile organic compounds (SVOCs). The data also confirmed the absence of free
Groundwater standards, as defined in Title 15A, North Carolina Administrative Code, Subchapter 2L
December 2018 Free Product Recovery Report 2 January 2019

product in the Site recovery wells in January, June, and July of 2017. S&ME, Inc., requested closure of
No. 2 fuel oil light -off UST Incident No. 11186 in a Site Closure Report (S&ME 2017a) based on these
results. In a letter dated August 23, 2017, DEQ, Division of Waste Management, UST Section
determined that "prior to the granting of No Further Action status for this incident, groundwater
samples must be collected from the recovery wells."
In September and October 2017, free product levels were gauged in the five existing Site recovery wells
(RW-2R, RW-3, RW-4, RW-5, and RW-6). Free product (0.14 foot) was only detected in recovery well
RW-6. During the same field event, groundwater samples were collected from the Site monitoring
and recovery well network. The groundwater samples were analyzed for VOCs (by Standard Method
620013); for SVOCs, plus the 10 highest tentatively identified compounds (by U.S. Environmental
Protection Agency Method 625); and for volatile petroleum hydrocarbons (VPH) and extractable
petroleum hydrocarbons (EPH; by the Massachusetts Department of Environmental Protection
Method).
COCs were not detected in the groundwater samples collected from Site monitoring wells in
September and October 2017. COC concentrations detected in the samples collected from Site
recovery wells in September and October 2017 were below the respective GCL and below 10 times
the 2B standards. The September and October 2017 sampling results were summarized in the
Groundwater Monitoring Report prepared by S&ME, dated November 21, 2017 (S&ME 2017b).
In June 2018, free product and water levels were gauged and groundwater samples were collected in
the monitoring and recovery wells (Anchor QEA 2018). The results are summarized as follows:
• Monitoring Wells
- No free product was detected in the monitoring wells.
- No VOCs were detected at concentrations above the associated 2L standards, GCL, or
2B standards multiplied by a factor of 10. The only VOC detected at a concentration
above the laboratory reporting limit was chloroform, a common laboratory
contaminant.
- No SVOCs or EPH or VPH fractions were detected at concentrations above the
laboratory method detection limits (MDLs).
Recovery Wells
- The free product recovery volume from recovery wells RW-3, RW-4, and RW-6 during
this reporting period (October 2017 through June 2018) using passive recovery
(oil -absorbent socks) was approximately 0.33 gallon.
- No free product was detected in the recovery wells when they were gauged
approximately 24 hours after oil -absorbent sock removal.
- Detected VOC and SVOC concentrations were below the respective GCL and the
associated 2B standard multiplied by a factor of 10.
December 2018 Free Product Recovery Report 3 January 2019

— Three EPH and VPH fraction standard ranges were detected at concentrations above
the laboratory MDLs and 2L standards.
1.2 Receptors
No drinking water supply wells are located within 1,000 feet of the UST Incident No. 11186 source
area, and there are no non -drinking water supply wells within 250 feet of the source area
(S&ME 2017a). The Catawba River is located within 500 feet of the source area. The Catawba River is
classified by DEQ in 15A NCAC 0213.0208 as a Water Supply V, Class B (Primary Recreation), and
Class C (Freshwater) surface water body.
1.3 Risk Classification and Cleanup Goals
For risk -based closure with an NRP filed with the Site's deed, the cleanup levels for the Duke Energy
Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186; intermediate priority site) specify no
free product greater than or equal to 1/8 inch and no exceedances of the GCL or 10 times the
2B standards (S&ME 2017b; DENR 2013).
December 2018 Free Product Recovery Report 4 January 2019

2 Well Gauging
The current monitoring and recovery well network consists of monitoring wells MW-1, MW-2, and
MW-10, and recovery wells RW-2R, RW-3, RW-4, RW-5, and RW-6. Table 1 presents monitoring well
and recovery well construction details. Monitoring well and recovery well locations are shown in
Figure 3.
2.1 Recovery Well Measurements
Since free product recovery began in late 1992, approximately 1,280 gallons of free product have
been recovered through hand -bailing recovery, aggressive fluid vapor recovery, pump -and -treat
system operation, and passive recovery using oil -absorbent socks.
Oil -absorbent socks were installed in recovery wells RW-2R, RW-3, RW-4, RW-5, and RW-6 in June
and removed in July 2017. The free product recovery volume for June and July 2017 using this
passive recovery method was approximately 0.85 gallon (S&ME 2017b).
S&ME installed oil -absorbent socks in recovery wells RW-3, RW-4, and RW-6 on October 4, 2017,
following the September and October 2017 groundwater sampling and free product level gauging
event. These socks were removed and replaced in June 2018 as described in Section 1.1.2.
On December 18, 2018, Anchor QEA removed the oil -absorbent socks from recovery wells RW-3,
RW-4, and RW-6. The free product recovery volume during this reporting period (June 2018 through
December 2018) using this passive recovery method was about the same as recovered during the
previous reporting period, approximately 0.33 gallon. Free product recovery was estimated using the
weight of the recovered socks, as presented in Equation 1. Individual recovery well free product
recovery details for this reporting period are summarized in Table 2.
Equation 1
P = ([W1 — W2] * C)/D
where:
P = product volume recovered (gallons)
W1 = weight of used oil -absorbent sock retrieved (pounds)
W2 = weight of dry oil -absorbent sock (pounds)
C = conversion factor of 0.75 for weight of water/other material in used oil -
absorbent sock retrieved
D = density of No. 2 fuel oil (7.41 pounds/gallon)
December 2018 Free Product Recovery Report 5 January 2019

On December 18, 2018, Anchor QEA measured depth -to -groundwater and depth -to -product in
recovery wells RW-2R, RW-3, RW-4, RW-5, and RW-6 using an oil -water interface meter. No free
product was detected in the Site recovery wells.
Current and historical free product thickness measurements are summarized in Table 2, and a current
free product thickness map is included as Figure 4. The June 2018 recovery well gauging log is
included in Appendix A.
2.2 Monitoring Well Measurements
On December 18, 2018, Anchor QEA measured depth -to -groundwater in monitoring wells MW-1,
MW-2, and MW-10 using a standard water level meter.
Current and historical depth -to -water measurements are included in Table 3. Figure 5 presents the
groundwater elevation data obtained from the December 2018 monitoring event. The December
2018 monitoring well gauging log is included in Appendix A.
December 2018 Free Product Recovery Report 6 January 2019

3 Results and Discussion
3.1 Free Product Recovery
Approximately 0.33 gallon of free product was recovered from recovery wells RW-3, RW-4, and RW-6
through passive recovery with oil -absorbent socks from June 2018 through December 2018.
Approximately 1 hour after oil -absorbent sock removal, no free product was detected in recovery
wells RW-2R, RW-3, RW-4, RW-5, or RW-6.
Current and historical free product thickness trends are summarized in Figures 6 and 7. As shown in
these figures, there has been a downward trend in overall free product thickness since June 1994.
Limited free product has been recovered over the past approximately 10 years as free product
thicknesses have decreased in Site recovery wells. Cumulative free product recovery is summarized in
Figure 8.
3.2 Water Level Gauging
On the basis of the December 18, 2018 water level measurements, the depths to water levels were
21.56 feet below top of casing (TOC) and 21.28 feet below TOC in MW-2 and MW-10, respectively.
(All wells on Site are flush mount; the TOC elevations are within a few inches of the concrete grade at
the Site.) The water level depths in the remaining wells on Site ranged from 27.82 feet below TOC in
RW-4 to 29.73 feet below TOC in RW-6. These water level depths are similar to past measurements
and are shown in Figure 5.
December 2018 Free Product Recovery Report 7 January 2019

4 Conclusions and Recommendations
4.1 Summary and Conclusions
On December 18, 2018, Anchor QEA performed the following activities:
• Removed and weighed the oil -absorbent socks that had been in -place in recovery wells RW-3,
RW-4, and RW-6 since June 2018
• Measured depths to the water table in monitoring wells MW-1, MW-2, and MW-10 using an
electronic water level meter
• Measured thicknesses of free product and depths to the water table using an electronic
oil -water interface probe in recovery wells RW-2R, RW-3, RW-4, RW-5, and RW-6
• Installed new oil -absorbent socks across the water table in recovery wells RW-3, RW-4, and
RW-6
The results of these activities are summarized as follows:
• No free product was measured in the recovery wells. Evidence (such as sheen on water level
tape or petroleum odors) of free product was not identified in the monitoring wells.
• The free product recovery volume from recovery wells RW-3, RW-4, and RW-6 during this
reporting period (June 2018 through December 2018) using passive recovery (oil -absorbent
socks) was approximately 0.33 gallon. There has been a downward trend in overall free
product recovery since 1994, with limited free product recovery over the past approximately
10 years (see Figure 8).
The depths to water levels were 21.56 feet below TOC and 21.28 feet below TOC in MW-2 and
MW-10, respectively. The water level depths in the remaining wells on Site ranged from 27.82 feet
below TOC in RW-4 to 29.73 feet below TOC in RW-6. These water levels depths are similar to past
measurements and are shown in Figure 5.
4.2 Recommendations
Current and historical data indicate that, excluding a small amount of free product occasionally
detected in certain recovery wells, the Site risk classification would be low, and the Site would be
eligible for closure with an NRP designation recorded for the Site parcel at the Gaston County
Register of Deeds.
Anchor QEA recommends that the oil -absorbent socks be removed and the volume of product
recovered be measured in March 2019. Anchor QEA further recommends that the removed socks not
be replaced with new socks immediately following the March 2019 event. Rather, Anchor QEA will
return to the site at least 2 weeks following the March 2019 event to gauge the fluid in the wells with
an oil -water interface probe. If no more than 1/8-inch of free product is identified in any well, then
December 2018 Free Product Recovery Report 8 January 2019

Duke Energy will request the risk classification be changed to low and petition the DEQ for Site
closure with an NRP. Alternatively, if more than 1/8-inch of free product is present in any well, then
new oil -absorbent socks will be placed in those wells.
December 2018 Free Product Recovery Report 9 January 2019

5 References
Anchor QEA of North Carolina, PLLC (Anchor QEA), 2018. 2078 Groundwater Monitoring Report, Allen
Steam Station Fuel Light -Off Underground Storage Tank, Incident No. 77786. July 2018.
DENR (North Carolina Department of Environment and Natural Resources), 2013. Guidelines for
Assessment and Corrective Action for UST Releases. Division of Waste Management, UST
Section. July 15, 2008 Version, Change 3, effective December 1, 2013.
DEQ (North Carolina Department of Environmental Quality), 2018. Letter to: Duke Energy Carolinas,
LLC. Regarding: Acknowledgement of Receipt, Groundwater Monitoring Report, Allen Steam
Station. August 9, 2018.
S&ME (S&ME, Inc.), 2017a. Site Closure Report. Duke Power - Allen Steam Station, Incident No.
11186, Belmont, North Carolina. Prepared for Duke Energy Corporation. July 2017.
S&ME, 2017b. Groundwater Monitoring Report. Allen Steam Station Fuel Oil Light -Off UST, Incident
#11186, Belmont, North Carolina. Prepared for Duke Energy Corporation. November 21, 2017.
December 2018 Free Product Recovery Report 10 January 2019

Tables

Table 1
Monitoring and Recovery Well Construction Information
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well Number
Well
Casing
Diameter
(inches)
Top of
Casing
Elevation
(feet)
Depth of
Well
(feet)
Screened Interval
(feet bgs)
Installation Date
Closure Date
MW-1
2
589.68
40
24.2-34.2
April 21, 1993
MW-2
2
589.27
35
23.8-34.0
April 14, 1993
MW-3
2
591.70
28.4
17.2-27.2
April 14, 1993
May 18, 2006
MW-4
2
592.44
31
19.4-29.4
June 15, 1994
May 18, 2006
MW-5
2
591.99
31
19.4-29.4
June 15, 1994
May 18, 2006
MW-6
2
592.50
31
19.2-29.2
June 14, 1994
October 8, 2002
MW-7
2
589.37
31
19.0-29.6
June 15, 1994
October 8, 2002
MW-8
2
591.49
49.5
42.5-47.5
June 15, 1994
May 18, 2006
MW-9
2
591.88
34.5
17.5-33.2
July 26, 1994
November 8, 2006
MW-10
2
589.39
34.7
17.5-33.2
July 26, 1994
DMW-1
2
589.61
91
85.2-90.2
October 9, 1996
August 10, 2009
RW-1
4
588.50
39
18.7-38.7
April 6, 1993
August 10, 2009
RW-2
4
588.27
40
19.4-39.4
April 7, 1993
August 10, 2009
RW-2R
4
589.08
40
20.0-40.0
May 10, 2010
RW-3
4
588.65
45
24.2-44.2
April 13, 1993
RW-4
4
588.50
44
23.2-43.2
April 13, 1993
RW-5
4
589.67
44.8
23.8-43.8
April 20, 1993
RW-6
4
589.68
45
24.2-44.2
April 27, 1993
Notes:
a. Wells were resurveyed in May 2010.
b. Well information was obtained from the Allen Steam Station Fuel Oil Light -Off Underground Storage Tank Semi -Annual Groundwater
Monitoring Report —Incident #11186, dated February 19, 2016, prepared by Duke Energy.
bgs: below ground surface
Page 1 of 14

Table 2
Free Product Recovery Information and Cumulative Volume Recovered
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Recovery Period
Product
Recovered
(gallons)
Cumulative
Product
Recovered
(gallons)
Recovery Well Free Product Thickness (feet)**
Notes
RW-1
RW-2
RW-2R
RW-3
RW-4
RW-5
RW-6
Through February 1994
220
220
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Recovery from RWs 1 through 5
March 1994
68
288
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Recovery primarily from RW-5
April 1994
41
329
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Recovery primarily from RW-2
May 1994
80
409
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Recovery from RWs 1, 2, 3, and 5
June 1994
75
484
2.1
0.1
N/A
1.2
0.9
0.1
1.7
Recovery primarily from RWs 2 and 5
July 1994
15
499
1.7
1.9
N/A
0.3
0.75
0.1
0.55
Operations with free product only pumps
August 1994
22
521
0.9
0.1
N/A
1.5
0.3
0.1
1.2
Recovery primarily from RWs 1, 2, and 5
September 1994
21
542
2.39
3.87
N/A
1.51
2.23
0.58
0.3
Recovery primarily from RWs 5 and 6
October 1994
26
568
1.1
0.1
N/A
0.7
1.1
1.1
0.1
None
November 1994
17
585
1.4
2.3
N/A
1.2
0.2
0.2
1.4
Recovery primarily from RWs 1, 2, and 5
December 1994
12
597
0.7
3.5
N/A
0.1
1.6
1.3
0.1
Pumps moved to RWs 2 and 4 on December 29, 1994
January 1995
22
619
0.5
0.2
N/A
1.1
1.3
0.2
1.8
Pumps located in RWs 2 and 5
February 1995
16
635
0.8
0.5
N/A
0.2
In Svc.
1.2
In Svc.
None
March 1995
16
651
0.2
2.2
N/A
1.5
1.2
0.2
1.2
Pumps in wells RWs 1 and 5
April 1995
17
668
0.7
2
N/A
0.5
0.2
0.2
1.6
Pumps in RWs 4 and 5
May 1995
14
682
0.9
0.1
N/A
1.4
1.7
3.4
0.1
Pumps in RWs 2 and 6
June 1995
12
694
2.2
3.2
N/A
1.5
0.2
0.2
1.4
Pumps in RWs 4 and 5
July 1995
12
706
0.2
0.2
N/A
3.2
2.4
4.2
2.6
Pumps in RWs 1 and 2
August 1995
12
718
0.2
0.15
N/A
0.5
0.6
1.0
0.5
None
September 1995
11
729
0.3
0.4
N/A
0.2
0.3
1.5
1.2
Pumps moved to RWs 5 and 6 inside fan room
October 1995
4
733
0.2
4.7
N/A
1.8
2
0.1
0.1
Recovery entirely from wells inside fan room to allow work around RWs 1 through 4 for installation of components for pump -and -treat system
November 1995
7
740
1
<0.2
N/A
1.7
2.2
2.7
<0.2
Pumps in RWs 2 and 6
December 1995
5
745
1.2
1
N/A
1.9
2.2
<0.2
<0.2
Pumps in RWs 5 and 6
January 1996
9
754
1.4
<0.2
N/A
1.9
2.2
3.2
<0.2
Pumps in RWs 2 and 6
February 1996
7
761
2
2.4
N/A
1
0.7
<0.2
<0.2
Pumps in RWs 5 and 6
March 1996
10
771
<0.2
1.8
N/A
1.2
1.2
0.8
<0.2
Pumps in RWs 1 and 6
April 1996
7
778
2.9
3.2
N/A
1.9
1.3
0.4
0.5
Pumps in RWs 5 and 6
May 1996
8
786
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Free product not measured due to construction
June 1996
7
793
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Free product not measured due to construction
July 1996
5
798
0.96
1.05
N/A
0.26
3.06
2.58
7.66
Depths measured on July 17, 1996, prior to pump -and -treat start-up
August -October 1996
130
928
0.35
2.98
N/A
0.18
2.7
0.1
0.1
Pumps removed 3 days prior to monitoring in RWs 1 through 4; free product measured during pump operation in RWs 5 and 6
November 1996-January 1997
25
953
0.01
2.4
N/A
0.65
1.4
0.15
0.01
None
February -April 1997
35
988
0.62
1.02
N/A
0.84
3.02
0.04
0.22
None
May -July 1997
40
1028
0.65
2.0
N/A
0.5
0.45
0.02
0.45
None
August 1997-January 1998
40
1068
0.50
2.40
N/A
0.30
0.40
0.30
0.70
Dual controlled pumps in RWs 1 and 2 were replaced with a new high -capacity pump; free product levels were high in RW-2 due to pump problem
prior to replacement
February -July 1998
20
1088
0.93
0.00
N/A
0.90
0.00
0.42
0.54
Ejector system pump in RW-4 was replaced with a new high -capacity Hammerhead pump on June 26, 1998
Page 2 of 14

Table 2
Free Product Recovery Information and Cumulative Volume Recovered
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Recovery Period
Product
Recovered
(gallons)
Cumulative
Product
Recovered
(gallons)
Recovery Well Free Product Thickness (feet)**
Notes
RW-1
RW-2
RW-2R
RW-3
RW-4
RW-5
RW-6
August 1998-January 1999
15
1103
1.50
0.01
N/A
1.00
0.00
0.40
0.45
Pumping did not occur for 1 month during period due to plant maintenance
February -July 1999
12
1115
0.40
0.00
N/A
0.00
0.70
0.40
0.50
Active pumping in RWs 2, 3, 5, and 6
August 1999-January 2000
17
1132
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Includes 4 gallons recovered during September 9, 1999 AFVR event; free product not measured due to overhead construction in plant area
February -July 2000
78
1210
1.20
0.20
N/A
0.10
0.30
0.25
0.05
Includes 68.5 gallons recovered during June 4, 2000 AFVR event; product thickness measured on July 21, 2000
August 2000-January 2001
15
1225
0.50
0.00
N/A
0.00
0.50
0.00
0.05
Active pumping in RWs 2, 3, 5, and 6
February -July 2001
9
1234
2.26
1.13
N/A
0.00
1.14
0.42
0.00
Active pumping in RWs 2, 3, 5, and 6; pumps in RWs 2 and 5 will require maintenance
August 2001-January 2002
10
1244
0.00
0.00
N/A
0.01
0.26
0.29
0.09
Active pumping in RWs 1, 2, 4, and 5
February -August 2002
7
1251
0.00
0.00
N/A
0.00
0.00
0.51
0.08
Active pumping in RWs 1, 2, 4, 5, and 6
August 2002-February 2003
6
1257
0.00
0.23
N/A
0.20
0.00
0.18
0.00
Active pumping in RWs 1, 2, 4, 5, and 6
February -August 2003
4
1261
0.00
0.00
N/A
0.00
0.00
0.45
0.00
Active pumping in RWs 1, 2, 4, 5, and 6
September 2003-February 2004
4
1265
0.00
0.00
N/A
0.00
0.01
N/A
0.00
Active pumping in RWs 1, 2, 5, and 6; RW-5 was not accessible
February -August 2004
1
1266
0.07
0.00
N/A
0.02
0.00
0.30
0.00
Active pumping in RWs 1, 2, 5, and 6
September 2004-February 2005
2
1268
1.40
0.00
N/A
1.40
0.00
0.00
0.10
Active pumping in RWs 1, 2, 5, and 6; pump in RW-1 not operating properly
February -August 2005
0.25
1268.25
0.00
0.00
N/A
0.02
0.02
0.50
0.02
Active pumping in RWs 1, 2, 5, and 6; RW-5 pump had a blocked inlet at the time of measurement
September 2005-January 2006
2
1270.25
0.00
0.00
N/A
N/A
0.15
0.15
0.01
Active pumping in RWs 1, 2, 5, and 6; RW-3 was inaccessible due to plant activity at the time of monitoring
February -July 2006
1
1271.25
0.00
0.00
N/A
0.20
N/A
0.00
0.00
Active pumping in RWs 1, 2, 5, and 6; RW-4 was inaccessible due to plant activity at the time of monitoring
August 2006-January 2007
0.25
1271.5
0.00
0.00
N/A
N/A
0.21
0.11
0.03
Active pumping in RWs 1, 2, 5, and 6; RW-3 was inaccessible due to plant activity at the time of monitoring
February -July 2007
1
1272.5
0.00
0.50
N/A
N/A
0
1.02
j 0.01
Active pumping in RWs 1, 4, and 6; pump in RW-5 was not operating; RW-3 was inaccessible due to plant activity at the time of monitoring
August 2007-January 2008
0.5
1273
0.0
N/A
N/A
N/A
0.0
0.0
N/A
Active pumping in RWs 1, 2, 4, 5, and 6; RWs 2, 3, and 6 were inaccessible due to plant activity at the time of monitoring
February -July 2008
0.25
1273.25
0.0
N/A
N/A
N/A
0.0
0.0
N/A
Active pumping in RWs 1, 2, 4, 5, and 6; RWs 2, 3, and 6 were inaccessible due to plant activities at the time of monitoring
August 2008-January 2009
0
1273.25
0.0
N/A
N/A
N/A
0.0
0.0
N/A
Active pumping in RWs 1, 2, 4, 5, and 6; pumps in RWs 2, 3, and 6 were inaccessible at the time of monitoring
February -July 2009
N/A
1273.25
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Due to increased construction activities and safety concerns, the recovery wells were inaccessible for measurements
August 2009-January 2010
0.25
1273.5
N/A
N/A
N/A
N/A
N/A
0.07
N/A
Active pumping in RW-5; RWs 4 and 6 not pumped during this period
February -July 2010
2
1275.5
N/A
N/A
0.12
0
0.01
0.03
0
Active pumping in RWs 3 and 5
August 2010-January 2011
0.5
1276
N/A
N/A
0.34
0
0.14
0
0
Active pumping in RWs 3 and 5
February -September 2011
0.5
1276.5
N/A
N/A
0.16
0.01
0.01
0.01
0.01
Active pumping in RWs 3 and 5
October 2011-January 2012
0.25
1276.75
N/A
N/A
0.35
0
0.02
0
0.1
Active pumping in RWs 3 and 5
February -July 2012
0.25
1277
N/A
N/A
0.05
0.01
0.01
0.02
0.05
Active pumping in RWs 3 and 5
August 2012-January 2013
0.1
1277.1
N/A
N/A
0.26
0.04
0.01
0.03
0.05
Active pumping in RWs 3 and 5
February -July 2013
0.25
1277.35
N/A
N/A
0.9
0
0
0.05
0.05
Active pumping in RWs 3 and 5
August 2013-January 2014
0.1
1277.45
N/A
N/A
1.29
0.19
0.45
0.22
0.13
Active pumping in RW-5
February -July 2014
0.1
1277.55
N/A
N/A
0
0
0.21
0
0
Active pumping in RWs 3 and 5
August 2014-January 2015
0.25
1277.8
N/A
N/A
0
0.01
0.03
0
Dry
Active pumping in RWs 3, 4, and 5
January -July 2015
0.1
1277.9
N/A
N/A
0
0
0
0
Dry
Active pumping in RWs 3, 4, and 5
July 2015-January 2016
0
1277.9
N/A
N/A
0.01
0
0
0.02
0
System shut down on October 7, 2015
January -July 2016
0.25
1278.15
N/A
N/A
0
0
0.1
0
0.01
Active pumping in RWs 2 and 5; restarted on March 9, 2016
Page 3 of 14

Table 2
Free Product Recovery Information and Cumulative Volume Recovered
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Cumulative
Product
Product
Recovery Well Free Product Thickness (feet)**
Recovered
Recovered
Recovery Period
(gallons)
(gallons)
RW-1
RW-2
RW-2R
RW-3
RW-4
RW-5
RW-6
Notes
Well pump in RW-3 not pumping; further investigation needed; the system has been operating pumps RWs 2R, 4, and 5 since the last time readings
July 2016—January 2017
0.25
1278.4
N/A
N/A
0
0
0
0
0
were taken
Total fluids recovery system shut down May 3, 2017; oil -absorbent socks used for free product recovery in RWs 2R, 3, 4, 5, and 6 in June and
January —July 2017
0.85
1279.25
N/A
N/A
0
0
0
0
0.01
July 2017
Oil -absorbent socks not installed in recovery wells from July 5 through October 3, 2017; oil -absorbent socks installed in RWs 3, 4, and 6 on
July —October 2017
N/A
1279.25
N/A
N/A
<0.01
0.02
<0.01
<0.01
0.14
October 4, 2017
Oil -absorbent socks removed and replaced in RWs 3, 4, and 6 on June 19 and 20, 2018
Estimated product removals:
October 2017—June 2018
0.33
1279.58
N/A
N/A
0.00
0.00
0.00
0.00
0.00
RW-3 = 0.09 gallons (6/19/18 used sock weight = 1.0625 pounds)
RW-4 = 0.11 gallons (6/19/18 used sock weight = 1.25 pounds)
RW-6 = 0.13 gallons (6/19/18 used sock weight = 1.5 pounds)
Oil -absorbent socks removed and replaced in RWs 3, 4, and 6 on December 18, 2018
Estimated product removals:
June —December 2018
0.34
1279.92
N/A
N/A
0.00
0.00
0.00
0.00
0.00
RW-3 = 0.06 gallons (12/18/18 used sock weight = 0.76 pounds)
RW-4 = 0.05 gallons (12/18/18 used sock weight = 0.68 pounds)
RW-6 = 0.22 gallons (12/18/18 used sock weight = 2.42 pounds)
Notes:
January through October 2017 free product recovery information obtained from the July 31, 2017 Site Closure Report - Duke Power - Allen Steam Station, Incident No. 11186, and November 21, 2017 Groundwater Monitoring Report -Allen Steam Station Fuel Oil Light -Off UST, Incident #11186, prepared by
S&ME, Inc.
Oil -absorbent socks installed on October 4, 2017: CHEMTEX, Model No. OILM206. 1.5-inch diameter, 24-inch length. Dryweight of individual sock is 0.2 pound.
Oil -absorbent socks installed on June 20, 2018: EON Products, Inc., Model No. GRA210. 2.75-inch diameter, 18-inch length. Dry weight of individual sock is 0.375 pound.
June 2018 product recovery volume calculated using the following equation: P =([W 7 -W21 * C) / D, where: P = product volume recovered (gallons), W = weight of used absorbent sock retrieved (pounds), W2 = weight of dry absorbent sock (pounds), C = conversion factor of 0.75 for weight of water/other
material in used absorbent sock retrieved, and D = density of No. 2 fuel oil (7.41 pounds/gallon).
Recovery Methods:
Late 1992 through July 1996: bailing and free product pumps
September 1999: 1 AFVR
June 2000: 4 AFVRs
July 1996 to May 3, 2017: Total Fluids Recovery System
June 2017 to present: oil -absorbent socks
** Free product thicknesses are end -of -period measurements.
AFVR: Aggressive Fluid Vapor Recovery
In Svc.: in service
N/A: not available
RW: recovery well
Page 4 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
Februa 4, 1994
September 21, 1994
September 19, 1995
MW-1
589.68
28.75
560.93
27.68
562
27.88
561.8
MW-2
589.27
22.8
566.47
22.79
566.48
22.72
566.55
MW-3
591.7
25.38
566.32
24.68
567.02
24.85
566.85
MW-4
592.44
N/A
N/A
25.18
567.26
25.34
567.1
MW-5
591.99
N/A
N/A
24.89
567.1
25.3
566.69
MW-6
592.5
N/A
N/A
25.44
567.06
25.56
566.94
MW-7
589.37
N/A
N/A
22.22
567.15
22.45
566.92
MW-8
591.49
N/A
N/A
24.51
566.98
24.66
566.83
MW-9
591.88
N/A
N/A
24.83
567.05
25.07
566.81
MW-10
589.39
N/A
N/A
21.4
567.99
21.34
568.05
DMW-1
589.61
N/A
N/A
N/A
N/A
N/A
N/A
RW-1
589.33
30.18
559.15
27.57
561.76
27.39
561.94
RW-2
589.1
28.63
560.47
27.33
561.77
27.51
561.59
RW-3
588.65
28.97
559.68
27.81
560.84
28.09
560.56
RW-4
588.5
28.33
560.17
27.3
1 561.2
27.48
561.02
RW 5
589.67
1 29.06
1 560.61
1 27.88
561.79
1 28.01
1 561.66
RW 6
589.68
1 29.38
1 560.3
1 28.12
561.56
1 28.3
1 561.38
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
March 20, 1996
July 17, 1996
October 28, 1996
MW-1
589.68
N/A
N/A
25.2
564.48
27.31
562.37
MW-2
589.27
N/A
N/A
18.95
570.32
20.7
568.57
MW-3
591.7
23.93
567.77
N/A
N/A
23.51
568.19
MW-4
592.44
24.53
567.91
N/A
N/A
24.22
568.22
MW-5
591.99
24.12
567.87
N/A
N/A
23.85
568.14
MW-6
592.5
24.64
567.86
N/A
N/A
24.31
568.19
MW-7
589.37
21.64
567.73
N/A
N/A
21.16
568.21
MW-8
591.49
23.78
567.71
N/A
N/A
23.41
568.08
MW-9
591.88
N/A
N/A
23.25
568.63
24.26
567.62
MW-10
589.39
N/A
N/A
20.57
568.82
N/A
N/A
DMW-1
589.61
N/A
N/A
N/A
N/A
26.6
563.01
RW-1
588.5
N/A
N/A
23.7
564.8
26.54
561.96
RW-2
588.27
N/A
N/A
23.79
564.48
26.1
562.17
RW-3
588.65
N/A
N/A
24.34
564.31
26.6
562.05
RW-4
588.5
N/A
N/A
23.35
565.15
25.81
562.69
RW-5
589.67
N/A
N/A
25.57
564.1
32.02
557.65
RW-6
589.68
N/A
N/A
25.53
564.15
36.52
553.16
Note:
N/A: not available
Page 5 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
Januar 6, 1997
Aril 28, 1997
July 23 and 30, 1997
MW-1
589.68
28.28
561.4
27.32
562.36
28.28
561.4
MW-2
589.27
20.65
568.62
21.14
568.13
21.82
567.45
MW-3
591.7
23.28
568.42
23.24
568.46
23.78
567.92
MW-4
592.44
24.12
568.32
24.16
568.28
24.43
568.01
MW-5
591.99
23.64
568.35
23.67
568.32
23.98
568.01
MW-6
592.5
24.08
568.42
21.16
571.34
24.48
568.02
MW-7
589.37
21.04
568.33
21.14
568.23
21.47
567.9
MW-8
591.49
23.12
568.37
23.26
568.23
23.64
567.85
MW 9
591.88
24.22
567.66
23.33
568.55
23.88
568
MW 10
589.39
N/A
N/A
N/A
N/A
N/A
N/A
DMW-1
589.61
27.12
562.49
26.73
562.88
27.42
562.19
RW-1
588.5
27.8
560.7
26.51
561.99
26.65
561.85
RW-2
588.27
27.66
560.61
26.12
562.15
26.25
562.02
RW-3
588.65
27.45
561.2
26.59
562.06
26.78
561.87
RW-4
588.5
26.81
561.69
25.98
562.52
26.97
561.53
RW-5
589.67
29.77
559.9
27.87
561.8
27.84
561.83
RW-6
589.68
28.3
561.38
27.89
561.79
28.02
561.66
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 9 and 15, 1998
July 8 and 22, 1998
January 18 and February 11, 1999
MW-1
589.68
29.29
560.39
29.44
560.24
29.35
560.33
MW-2
589.27
21.64
567.63
19.26
570.01
22.86
566.41
MW-3
591.7
23.98
567.72
22.62
569.08
24.66
567.04
MW-4
592.44
24.61
567.83
23.72
568.72
25.22
567.22
MW-5
591.99
24.1
567.89
N/A
N/A
24.92
567.07
MW-6
592.5
24.61
567.89
N/A
N/A
25.46
567.04
MW-7
589.37
21.61
567.76
N/A
N/A
22.38
566.99
MW-8
591.49
23.62
567.87
N/A
N/A
24.27
567.22
MW 9
591.88
23.93
567.95
N/A
N/A
24.94
566.94
MW 10
589.39
20.96
568.43
N/A
N/A
21.38
568.01
DMW-1
589.61
28.3
561.31
27.92
561.69
28.8
560.81
RW-1
588.5
27.68
560.82
27.81
560.69
29.53
558.97
RW-2
588.27
27.36
560.91
31.75
556.52
32.11
556.16
RW-3
588.65
27.95
560.7
28.14
560.51
29.8
558.85
RW-4
588.5
26.96
561.54
27
561.5
30.3
558.2
RW-5
589.67
28.85
560.82
32.51
557.16
32.96
556.71
RW-6
589.68
27.91
561.77
29.48
560.2
33.72
555.96
Note:
N/A: not available
Page 6 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
July 12 and 30, 1999
January 12, 2000
July 11 and 21, 2000
MW-1
589.68
30.03
559.65
29.6
560.08
28.73
560.95
MW-2
589.27
23.6
565.67
23.23
566.04
23.65
565.62
MW-3
591.7
25.17
566.53
25.4
566.3
25.71
565.99
MW-4
592.44
25.71
566.73
25.98
566.46
26.27
566.17
MW-5
591.99
25.4
566.59
25.53
566.46
25.91
566.08
MW-6
592.5
25.92
566.58
26.07
566.43
26.43
566.07
MW-7
589.37
22.91
566.46
23.21
566.16
23.42
565.95
MW-8
591.49
24.98
566.51
25.17
566.32
25.52
565.97
MW 9
591.88
25.56
566.32
25.78
566.1
26.02
565.86
MW 10
589.39
21.95
567.44
22.29
567.1
22.21
567.18
DMW-1
589.61
30.47
559.14
28.44
561.17
28.3
561.31
RW-1
588.5
28.96
559.54
N/A
N/A
26.93
561.57
RW-2
588.27
31.2
557.07
N/A
N/A
26.38
561.89
RW-3
588.65
29.5
559.15
N/A
N/A
27.82
560.83
RW-4
588.5
28.61
559.89
N/A
N/A
27.34
561.16
RW-5
589.67
32.96
556.71
N/A
N/A
28.74
560.93
RW-6
589.68
31.38
558.3
N/A
N/A
28.91
560.77
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 8, 2001
July 16, 2001
January 29 and February 22, 2002
MW-1
589.68
31.17
558.51
30.02
559.66
31.38
558.3
MW-2
589.27
24.63
564.64
23.75
565.52
24.43
564.84
MW-3
591.7
26.58
565.12
25.84
565.86
26.24
565.46
MW-4
592.44
27.15
565.29
26.38
566.06
26.88
565.56
MW-5
591.99
26.82
565.17
26
565.99
26.45
565.54
MW-6
592.5
27.38
565.12
26.54
565.96
27.01
565.49
MW-7
589.37
24.37
565
23.57
565.8
24.12
565.25
MW-8
591.49
26.47
565.02
25.62
565.87
26.2
565.29
MW 9
591.88
26.99
564.89
26.21
565.67
27.36
564.52
MW 10
589.39
22.97
566.42
22.32
567.07
23.18
566.21
DMW-1
589.61
31.22
558.39
30.41
559.2
30.86
558.75
RW-1
588.5
N/A
N/A
29.58
558.92
29.65
558.85
RW-2
588.27
N/A
N/A
30.74
557.53
29.38
558.89
RW-3
588.65
N/A
N/A
30.26
558.39
29.79
558.86
RW-4
588.5
N/A
N/A
28.77
559.73
29.27
559.23
RW-5
589.67
N/A
N/A
32.56
557.11
31.78
557.89
RW-6
589.68
N/A
N/A
30.2
559.48
30.81
558.87
Note:
N/A: not available
Page 7 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
July 17 and August 19, 2002
January 7 and February 14, 2003
July 14 and August 20, 2003
MW-1
589.68
31.98
557.70
30.25
559.43
28.65
561.03
MW-2
589.27
24.57
564.70
23.37
565.90
22.62
566.65
MW-3
591.7
26.57
565.13
25.35
566.35
24.64
567.06
MW-4
592.44
27.06
565.38
25.89
566.55
25.18
567.26
MW-5
591.99
26.73
565.26
25.52
566.47
24.81
567.18
MW-6
592.5
27.34
565.16
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
24.21
565.16
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
26.49
565.00
25.19
566.30
24.45
567.04
MW 9
591.88
27.42
564.46
25.93
565.95
24.99
566.89
MW 10
589.39
22.68
566.71
21.93
567.46
21.10
568.29
DMW-1
589.61
31.40
558.21
29.80
559.81
28.98
560.63
RW-1
588.5
34.56
553.94
28.92
559.58
32.90
555.60
RW-2
588.27
35.54
552.73
29.59
558.68
33.65
554.62
RW-3
588.65
31.57
557.08
29.29
559.36
27.30
561.35
RW-4
588.5
32.95
555.55
28.34
560.16
26.72
561.78
RW-5
589.67
33.32
556.35
30.96
558.71
35.45
554.22
RW-6
589.68
33.61
556.07
29.98
559.70
14.60
575.08
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 30 and February 24, 2004
July 19 and August
18, 2004
January 17 and February 18, 2005
MW-1
589.68
29.80
559.88
28.65
561.03
29.55
560.13
MW-2
589.27
23.59
565.68
22.62
566.65
23.10
566.17
MW-3
591.7
25.65
566.05
24.64
567.06
25.08
566.62
MW-4
592.44
26.27
566.17
25.18
567.26
25.68
566.76
MW-5
591.99
25.89
566.10
24.81
567.18
25.27
566.72
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
25.74
565.75
24.45
567.04
24.91
566.58
MW 9
591.88
25.23
566.65
24.99
566.89
25.25
566.63
MW 10
589.39
22.31
567.08
21.10
568.29
21.86
567.53
DMW-1
589.61
29.23
560.38
28.98
560.63
28.96
560.65
RW-1
588.5
18.20
570.30
30.57
557.93
20.61
567.89
RW-2
588.27
27.20
561.07
31.00
557.27
32.50
555.77
RW-3
588.65
25.50
563.15
27.16
561.49
26.81
561.84
RW-4
588.5
28.80
559.70
27.23
561.27
28.40
560.10
RW-5
589.67
Not accessible
N/A
34.96
554.71
33.70
555.97
RW-6
589.68
33.00
556.68
33.40
556.28
28.72
560.96
Note:
N/A: not available
Page 8 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
July 11 and August 19, 2005
January 23 and 31, 2006
July 3 and 21, 2006
MW-1
589.68
29.28
560.40
29.42
560.26
29.12
560.56
MW-2
589.27
22.84
566.43
22.74
566.53
23.19
566.08
MW-3
591.7
24.75
566.95
24.77
566.93
Abandoned
N/A
MW-4
592.44
25.33
567.11
25.28
567.16
Abandoned
N/A
MW-5
591.99
24.92
567.07
24.94
567.05
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
24.59
566.90
24.67
566.82
Abandoned
N/A
MW 9
591.88
25.54
566.34
24.82
567.06
25.48
566.40
MW 10
589.39
21.35
568.04
21.2
568.19
21.67
567.72
DMW-1
589.61
28.64
560.97
28.65
560.96
28.77
560.84
RW-1
588.5
33.7
554.80
31.8
556.70
32.65
555.85
RW-2
588.27
35.8
552.47
35.1
553.17
35.82
552.45
RW-3
588.65
27.3
561.35
Not accessible
N/A
27.79
560.86
RW-4
588.5
27.1
561.40
27.92
560.58
Not accessible
N/A
RW-5
589.67
33.3
556.37
30.97
558.70
34.65
555.02
RW-6
589.68
28.2
561.48
30.2
559.48
30.26
559.42
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 5 and 26, 2007
July 2 and August 24, 2007
January 28 and February 11, 2008
MW-1
589.68
28.63
561.05
30.92
558.76
32.16
557.52
MW-2
589.27
22.30
566.97
23.32
565.95
25.68
563.59
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW 9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW 10
589.39
21.18
568.21
21.92
567.47
23.89
565.50
DMW-1
589.61
27.86
561.75
29.18
560.43
30.87
558.74
RW-1
588.5
28.13
560.37
31.01
557.49
32.67
555.83
RW-2
588.27
29.21
559.06
30.03
558.24
Not accessible
N/A
RW-3
588.65
Not accessible
N/A
Not accessible
N/A
Not accessible
N/A
RW-4
588.5
27.36
561.14
30.08
558.42
31.52
556.98
RW-5
589.67
30.43
559.24
32.34
557.33
32.79
556.88
RW-6
589.68
29.55
560.13
32.29
557.39
Not accessible
N/A
Note:
N/A: not available
Page 9 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
June 23 and July 21, 2008
January 12 and 30, 2009
July 1, 2009
MW-1
589.68
30.53
559.15
29.84
559.84
28.10
561.58
MW-2
589.27
23.57
565.70
23.22
566.05
22.47
566.80
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW 9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
22.14
567.25
21.93
567.46
20.79
568.6
DMW-1
589.61
30.05
559.56
29.00
560.61
28.28
561.33
RW-1
588.5
30.15
558.35
30.47
558.03
Not accessible
N/A
RW-2
588.27
Not accessible
N/A
Not accessible
N/A
Not accessible
N/A
RW-3
588.65
Not accessible
N/A
Not accessible
N/A
Not accessible
N/A
RW-4
588.5
29.76
558.74
31.58
556.92
Not accessible
N/A
RW-5
589.67
31.9
557.77
30.98
558.69
Not accessible
N/A
RW-6
589.68
Not accessible
N/A
Not accessible
N/A
Not accessible
N/A
Note:
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 18 and February 15, 2010
May 10, 2010a
July 6, 2010
MW-1
589.68
29.21
560.47
28.9
560.78
29.58
560.10
MW-2
589.27
22.64
566.63
22.70
566.57
22.75
566.52
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW 9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
21.09
568.30
21.91
567.48
21.05
568.34
DMW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2R
589.08
N/A
N/A
28.45
560.63
29.32
559.76
RW-3
588.65
Not accessible
N/A
29.94
558.71
39.82
548.83
RW-4
588.5
27.53
560.97
27.63
560.87
28.37
560.13
RW-5
589.67
33.35
556.32
30.71
558.96
30.15
559.52
RW-6
589.68
29.28
560.40
29.25
560.43
36.62
553.06
Notes:
a. On May 10, 2010, existing wells were resurveyed.
N/A: not available
Page 10 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 17, 2011
July 28 and September 14, 2011b
January 5 and 25, 2012b
MW-1
589.68
30.97
558.71
29.85
559.83
30.96
558.72
MW-2
589.27
23.73
565.54
23.05
566.22
23.31
565.96
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
22.08
567.31
21.34
568.05
21.93
567.46
D MW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2Ra
589.08
31.02
567.35
29.8
559.28
31.5
557.58
RW-3
588.65
33.48
555.17
34.5
554.15
33.15
555.50
RW-4a
588.5
30.04
558.58
29.0
559.50
30.22
558.28
RW-5
589.67
38.61
551.06
37.5
552.17
35.35
554.32
RW-6
589.68
31.60
558.08
30.6
559.08
31.85
557.83
Notes:
a. Elevation was corrected for free product specific gravity that was assumed to be 0.85.
b. Monitoring wells were measured on the first date indicated, and recovery wells were measured on the second date indicated.
N/A: not available
Well
Number
Revised Top
of Casing
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
July 17, 2012
January 2 and 29, 2013b
July 11 and 25, 2013b
MW-1
589.68
31.16
558.52
31.40
558.28
29.85
559.83
MW-2
589.27
23.44
565.83
24.24
565.03
22.38
566.89
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
21.89
567.50
23.27
566.12
20.98
568.41
D MW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2Ra
589.08
30.50
558.80
30.45
558.85
29.1
559.98
RW-3a
588.65
32.10
556.58
30.04
558.64
31.5
557.15
RW-4a
588.5
1 29.46
559.05
1 29.38
1 559.13
1 28.3
560.20
RW-5a
1 589.67
36.52
553.18
33.20
556.50
32.5
557.17
RW-6a
1 589.68
31.25
1 558.47
31.10
558.62
29.9
1 559.78
Notes:
a. Elevation was corrected for free product specific gravity that was assumed to be 0.85.
b. Monitoring wells were measured on the first date indicated, and recovery wells were measured on the second date indicated.
N/A: not available
Page 11 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 2 and March 20, 2014b
July 23 and September 4, 2014b
January 28 and March 10, 2015b
MW-1
589.68
30.62
559.06
31.95
557.73
33.55
556.13
MW-2
589.27
23.05
566.22
22.98
566.29
23.29
565.98
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
21.94
567.45
21.42
567.97
22.12
567.27
D MW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2Ra
589.08
30.09
560.09
32.29
556.79
34.35
554.73
RW-3a
588.65
30.04
558.77
30.84
557.81
32.71
555.93
RW-4a
588.5
28.52
560.36
30.43
558.25
32.35
556.12
RW-5a
589.67
30.07
559.79
31.74
557.93
34.34
555.33
RW-6a
589.68
29.87
559.92
32.76
556.92
Dry
N/A
Notes:
a. Elevation was corrected for free product specific gravity that was assumed to be 0.85.
b. Monitoring wells were measured on the first date indicated, and recovery wells were measured on the second date indicated.
N/A: not available
Well
Number
Revised Top
of Casing
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
July 23 and 21, 2015b
January 21 and 18, 2016b
July 21 and 26, 2016b
MW-1
589.68
33.16
556.52
29.46
560.22
29.86
559.82
MW-2
589.27
23.78
565.49
22.29
566.98
21.89
567.38
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
22.33
567.06
21.23
568.16
21.02
568.37
D MW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2Ra
589.08
34.27
554.81
30.44
558.63
34.40
554.68
RW-3a
588.65
32.50
556.15
29.80
1 558.85
28.0
560.65
RW-4a
588.5
1 31.95
1 556.55
1 29.40
559.10
1 29.03
1 559.39
RW-5a
1 589.67
34.7
554.97
31.72
557.93
33.55
556.12
RW-6a
1 589.68
Dry
N/A
30.02
559.66
29.59
560.08
Notes:
a. Elevation was corrected for free product specific gravity that was assumed to be 0.85.
b. Monitoring wells were measured on the first date indicated, and recovery wells were measured on the second date indicated.
N/A: not available
Page 12 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
January 10 and 19, 2017a
June 7, 2017
June 21, 2017
MW-1
589.68
33.02
556.66
29.25
560.43
29.17
560.51
MW-2
589.27
24.23
565.04
N/A
N/A
N/A
N/A
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
22.59
566.80
N/A
N/A
N/A
N/A
DMW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2R
589.08
34.10
554.98
29.35
559.73
28.71
560.37
RW-3
588.65
31.35
557.30
24.37
564.28
28.45
560.20
RW-4
588.5
32.45
556.05
28.05
560.45
27.81
560.69
RW-5
589.67
35.50
554.17
30.54
559.13
29.52
560.15
RW-6
589.68
Dry
N/A
29.45
560.23
31.50
558.18
Notes:
a. Monitoring wells were measured on the first date indicated, and recovery wells were measured on the second date indicated.
N/A: not available
Well
Revised Top
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Number
of Casing
July 5, 2017
July 12, 2017b
September 28 and October 4, 2017`
MW-1
589.68
28.15
561.53
26.80
562.88
28.40
561.28
MW-2
589.27
N/A
N/A
N/A
N/A
22.86
566.41
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-9
591.88
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
MW-10
589.39
N/A
N/A
N/A
N/A
21.60
567.79
DMW-1
589.61
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
Abandoned
N/A
RW-2R
589.08
27.79
561.29
26.58
562.50
28.46
560.62
RW-3a
588.65
27.62
561.03
26.54
562.11
28.20
560.43
RW-4
588.5
26.88
561.62
25.59
562.91
27.60
560.90
RW-5
589.67
28.70
560.97
27.57
562.10
29.15
560.52
RW-6a
589.68
28.60
561.08
27.51
562.16
28.99
560.57
Notes:
a. Groundwater elevations were corrected for free product specific gravity that was assumed to be 0.85.
b. On July 12, 2017, 0.01 foot of free product was detected in RW-6.
c. On September 28 and October 4, 2017, 0.02 foot of free product was detected in RW-3, and 0.14 foot of free product was detected in RW-6.
N/A: not available
Page 13 of 14

Table 3
Current and Historical Groundwater Elevations
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
Well
Number
Revised Top
of Casing
Depth to Water
(feet)
Groundwater
Elevation
(feet)
Depth to Water
(feet)
Groundwater
Elevation
(feet)
June 19, 2018
December 18, 2018
MW-1
589.68
28.96
560.72
29.34
560.34
MW-2
589.27
22.16
567.11
21.56
567.71
MW-3
591.7
Abandoned
N/A
Abandoned
N/A
MW-4
592.44
Abandoned
N/A
Abandoned
N/A
MW-5
591.99
Abandoned
N/A
Abandoned
N/A
MW-6
592.5
Abandoned
N/A
Abandoned
N/A
MW-7
589.37
Abandoned
N/A
Abandoned
N/A
MW-8
591.49
Abandoned
N/A
Abandoned
N/A
MW 9
591.88
Abandoned
N/A
Abandoned
N/A
MW 10
589.39
21.76
567.63
21.28
568.11
DMW-1
589.61
Abandoned
N/A
Abandoned
N/A
RW-1
588.5
Abandoned
N/A
Abandoned
N/A
RW-2
588.27
Abandoned
N/A
Abandoned
N/A
RW-2R
589.08
28.46
560.62
28.90
560.18
RW-3
588.65
28.45
560.20
28.66
559.99
RW-4
588.5
27.45
561.05
27.82
560.68
RW-5
589.67
29.20
560.47
29.60
560.07
RW-6
589.68
29.02
560.66
29.73
559.95
Note:
N/A: not available
Page 14 of 14

Figures

Publish Date: 2019/01/07, 1:26 PM I User: alesueur
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ANCHOR
0EA
Figure 1
Site Location Map
Duke Energy Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186)
December 2018 Free Product Recovery Report

L1_ _`,
'
z"
ON
®I
Light -Off No. 2 UST System
Incident #11186
� � ;� t, % ,r � �� � ,� � '�" �,. �; fit►',
f
LEGEND: SOURCES:
1. Aerial Imagery: NC OneMap, 2015
Q 1,500-Foot Radius 2. Parcel Boundary: Gaston County GIS 0
Q Site Property Boundary 0 500
Feet
Publish Date: 2019/01/07, 1:28 PM I User: alesueur
Filepath: \\Ash evi Ilel\Asheville\GIS_Projects\Duke_Energy\Allen_SteamStation\Maps\2018_12_Monitoring Report\AQFig02_PartialSitePlan.mxd
?,ANCHOR Figure 2
QEA Site Layout Map
Duke Energy Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186)
December 2018 Free Product Recovery Report

UNIT #S UNIT #4 UNIT #3
EXHAUST STACK EXHAUST STACK EXHAUST STACK
0 0
NOTES: LEGEND:
THIS DRAWING IS BASED ON THE DUKE ENERGY FEBRUARY 2016 ® GROUNDWATER MONITORING WELL
SEMI-ANNUAL GROUNDWATER MONITORING REPORT.
RECOVERY WELL
Publish Date: 2019/01/09 10:41 AM I User: rpetrie
Filepath: \\Ashevillel\Asheville\Projects\Duke Energy\Allen Steam Station\CAD\Duke-Allen_Figures 3-5 Dec2018.dwg Figure 3 - Well Locations Map
kzANCHOR
QEA
a
NORTH
Figure 3
Recovery and Monitoring Well Locations Map
Duke Energy - Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186)
December 2018 Free Product Recovery Report

UNIT #S UNIT #4 UNIT #3
EXHAUST STACK EXHAUST STACK EXHAUST STACK
0 0
NOTES: LEGEND:
1. THIS DRAWING IS BASED ON THE DUKE ENERGY FEBRUARY 2016 ® GROUNDWATER MONITORING WELL
SEMI-ANNUAL GROUNDWATER MONITORING REPORT.
2. FREE PRODUCT THICKNESS VALUES WERE DETERMINED BASED ON RECOVERY WELL
FIELD MEASUREMENTS TAKEN ON DECEMBER 18, 2018.
ND - NOT DETECTED
Publish Date: 2019/01/09 10:38 AM I User: rpetrie
Filepath: \\Ashevillel\Asheville\Projects\Duke Energy\Allen Steam Station\CAD\Duke-Allen-Figures 3-5 Dec2018.dwg Figure 4 - Free Product Thickness Map
kZANCHOR
QEA
a
NORTH
Figure 4
Free Product Thickness Map -December 2018
Duke Energy - Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186)
December 2018 Free Product Recovery Report

UNIT #S UNIT #4 UNIT #3
EXHAUST STACK EXHAUST STACK EXHAUST STACK
0 0
NOTES:
1. GROUNDWATER ELEVATIONS WERE DETERMINED BASED ON
FIELD MEASUREMENTS TAKEN ON DECEMBER 18, 2018 FOR THE
MONITORING AND RECOVERY WELLS.
2. GROUNDWATER ELEVATIONS IN UST AREA ARE AFFECTED BY
POWERHOUSE FOUNDATIONS.
3. THIS DRAWING IS BASED ON THE DUKE ENERGY FEBRUARY 2016
SEMI-ANNUAL GROUNDWATER MONITORING REPORT FIGURE 7,
KC140103
® GROUNDWATER MONITORING WELL
RECOVERY WELL
560.72 - GROUNDWATER ELEVATION (FT.)
N/A - NOT APPLICABLE
Publish Date: 2019/01/09 10:43 AM I User: rpetrie
Filepath: \\Ashevillel\Asheville\Projects\Duke Energy\Allen Steam Station\CAD\Duke-Allen-Figures 3-5 Dec20l8.dwg Figure 5 - Water Level Elevations
a
NORTH
ANCHOR
Figure 5
kz QEAWater Level Elevations - December 2018
Duke Energy - Allen Steam Station Fuel Oil Light -Off UST (Incident No. 11186)
December 2018 Free Product Recovery Report

8
7
6
5
a 4
c
t
3
2 1 i1A, 1,' 4
J1,k iAM V Att:_ i
0
Mar-94 Jun-94 Sep-94 Jan-95 Apr-95 Jul-95 Oct-95 Feb-96 May-96
+RW-1 RW-2 TRW-2R w RW-3 # RW-4 t RW-5 0 RW-r
Filepath: \\ashevillel\asheville\Projects\Duke Energy\Allen Steam Station\Fuel Oil Light -Off UST\2019-01 Report\Draft Report\Figures
kzANCHOR Figure 6
QEA � Free Product Thickness Trend: June 1994 to April 1996
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
December 2018 Free Product Recovery Report

8
7
6
5
a 4
c
Y
V
L
H
3
2
1
Mar-96 Sep-97 Mar-99 Oct-00 Apr-02 Oct-M Apr-05 Oct-06 Apr-08 Oct-09 Apr-11 Oct-12 Apr-14 Oct-15 Apr-17 Oct-18 Apr-20
�RW_1 RW-2 RW-2R +RW-3 -* ---RWA - RW-5 +RW-5
Filepath: \\ashevillel\asheville\Projects\Duke Energy\Allen Steam Station\Fuel Oil Light -Off UST\2019-01 Report\Draft Report\Figures
kzANCHOR Figure 7
QEA� Free Product Thickness Trend: July 1996 to December 2018
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
December 2018 Free Product Recovery Report

1,400
1,200
1,000
0 —Product Recovered (gallons)
M
S00
v
L
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V
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600
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r r r r r r CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV CV
Year
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Hand
Bai I ing
Pump and
T
Socks
Filepath: \\ashevillel\asheville\Projects\Duke Energy\Allen Steam Station\Fuel Oil Light -Off UST\2019-01 Report\Draft Report\Figures
ANCHOR Figure 8
QEA�` Free Product Recovery Trend: 1994 to December 2018
Allen Steam Station Fuel Oil Light -Off Underground Storage Tank (Incident No. 11186)
December 2018 Free Product Recovery Report

Appendix A
Well Gauging Log

Anchor QEA of North Carolirta. FLLC
231 Haywood Street
Asheville, North Carolina 28801
828.2.81.3350
Well Gauging Log
A+aI�� C 110K
PROJECT NAME: 411., S Ttxt,, 5 y t
PROJECT NUMBER:
LOCATION: �1C`t,o� oNC
/'11 tz O,
L DATE:
SAMPLING PERSONNEL: , ,
)
L r WEATHER:
COMMENTS: Trc-
Well ID
Time Measured
DTW (feet)
Hotas
i
wt Lkj i
)Z w_ Z r)._
/ r t>
ZD
nr o p ec a u;
2_3
�3 5�
0 t7�—
"t -
c> >
$ L
r
j v I
Z
13/Ca AaC—
zw -
16>''
b ���p, c r
�.�ItB jj�� LL st3Sa.c d�-•.r
16S
W - - c,
51
- 'L U • 6 d - &L I!--
-iZu- � `�• L vD rc.
r C.cS 73 re L
"J3 a G
Sampling Personnel Signature: �(
Date:
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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

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QUAM ViVt\ .
DEQ Coal Combustion Residuals
Surface Impoundment
Closure Determination
Allen Steam Station
April 1, 2019

DEQ Coal Combustion Residuals Surface Impoundment Closure Determination
Allen Steam Station
Executive Summa
The Coal Ash Management Act (CAMA) establishes criteria for the closure of coal
combustion residuals (CCR) surface impoundments. The CCR surface impoundments located at
Duke Energy Carolinas, LLC's (Duke Energy) Allen Steam Station (Allen) in Gaston County, NC have
received a low -risk classification. Therefore, according to N.C. Gen. Stat. § 130A-309.214(a)(3),
the closure option for CCR surface impoundments is at the election of the North Carolina
Department of Environmental Quality (DEQ). 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 29, 2019 in Belmont, NC where
the community near Allen 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 impoundments at the Allen 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 Allen is more protective than leaving the material in place. DEQ determines
that CAMA Option A is the most appropriate closure method because removing the primary
source of groundwater contamination will reduce uncertainty and allow for flexibility in the
deployment of future remedial measures.
Duke Energy will be required to submit a final Closure Plan for the CCR surface
impoundments at Allen by August 1, 2019. The Closure Plan must conform to this election by
DEQ.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 1

Intrnrli irtinn
DEQ has evaluated the closure options submitted by Duke Energy for the two CCR surface
impoundments at the Allen Steam Station. This document describes the CAMA requirements for
closure of coal ash CCR surface impoundments, the DEQ evaluation process to make an election
under CAMA for the subject CCR surface impoundments at the Allen site, and the election by DEQ
for the final closure option.
II. Site History
Duke Energy owns and operates the Allen Steam Station which is located along the west
shore of Lake Wylie, a man-made reservoir created by the impoundment of the Catawba River.
Allen is a five -unit, 1,140 megawatts, coal-fired generating facility. Allen began commercial
operation in 1957 with units 1 and 2. Unit 3 began operation in 1959, unit 4 in 1960, and unit 5
in 1961. Allen historically wet sluiced CCR into two CCR surface impoundments located on the
property. These CCR surface impoundments are known as the Retired Ash Basin (RAB) which is
also referred to as the Inactive Ash Basin (IAB), and the Active Ash Basin (AAB), which are
impounded by the following dams: Retired Ash Basin (GASTO-016) and Active Ash Basin (GASTO-
061).
The RAB received CCR products from initial operation in 1957 until 1973, when it reached
capacity and was retired. Duke Energy then commissioned the AAB and began wet sluicing CCR
products into this new basin. In 2009, Duke Energy replaced its fly ash wet sluicing operation with
a dry ash handling system and began placing dry fly ash into a landfill constructed over a portion
of the RAB (Permit No. 36- 12). Duke Energy currently wet sluices only bottom ash into the AAB
and this operation will cease once the dry bottom ash system becomes operational, which is
scheduled to occur in early 2019. The two CCR surface impoundments are subject to the CAMA
closure requirements in N.C. Gen. Stat. § 130A-309.214(a)(3).
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).
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 2

Pursuant to N.C. Gen. Stat. § 130A-309.213(d)(1), DEQ has classified the CCR surface
impoundments at Allen as low -risk. The relevant closure requirements for low -risk CCR surface
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."
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 3

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

By referencing the closure options for high -risk CCR surface impoundments in
"subdivision (1)" or N.C. Gen. Stat. § 130A-309.214(a)(1), CAMA allows for closure of a low -risk
CCR surface impoundment in N.C. Gen. Stat. § 130A-309.214(a)(3) through the same removal
scenarios:
• "Convert the coal combustion residuals impoundment to an industrial landfill by
removing all coal combustion residuals and contaminated soil from the impoundment
temporarily, safely storing the residuals on -site, and complying with the requirements
for such landfills." N.C. Gen. Stat. § 130A-309.214(a)(1)a.; or
• "Remove all coal combustion residuals from the impoundment, return the former
impoundment to a nonerosive and stable condition and (i) transfer the coal
combustion residuals for disposal in a coal combustion residuals landfill, industrial
landfill, or municipal solid waste landfill or (ii) use the coal combustion products in a
structural fill or other beneficial use as allowed by law." N.C. Gen. Stat. § 130A-
309.214(a)(1)b.
IV. DEQ Election Process
Beginning with a letter to Duke Energy on October 8, 2018, DEQ began planning for a
thorough evaluation of the closure options for low -risk CCR surface impoundments before
making an election as outlined in Table 1 above. DEQ's objectives were to receive input on
closure options from Duke Energy and to engage with community members near low -risk sites.
DEQ outlined the following schedule in the October 8, 2018 letter:
• November 15, 2018 — Duke Energy submittal of revised closure option analyses and
related information
• January 29, 2019 — DEQ public meeting near Allen
• April 1, 2019 — DEQ evaluation of closure options
• August 1, 2019 — Duke Energy submittal of closure plan
• December 1, 2019 — Duke Energy submittal of updated corrective action plan for all
sources at the Allen site that are either CCR surface impoundments or hydrologically
connected to CCR surface impoundments
DEQ received the requested information from Duke Energy by November 15, 2018:
closure options analysis, groundwater modeling and net environmental benefits assessment.
These materials are posted on the DEQ website. Duke Energy provided the following options for
consideration: closure in place, full excavation with either an onsite or offsite landfill, and a hybrid
option that included some excavation with an engineered cap on a smaller footprint of the
existing CCR surface 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 Allen 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. DEQ's evaluation of closure in place and hybrid option based on
groundwater monitoring and modeling data is provided in Attachment A. That analysis
ALLEN 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 Belmont, NC near Allen on January 29, 2019. There
were 116 members of the public who attended the meeting. Approximately 1090 comments
were received during the comment period, which closed on February 15, 2019. The majority of
commenters requested that the coal ash be removed from the CCR surface impoundments and
moved to dry lined storage away from waterways and groundwater. Only one commenter
specifically requested closure -in -place. No commenters directly addressed the hybrid option. A
review and response to comments are included in Attachment B.
V. DEQ Evaluation of Closure Options
DEQ has evaluated the closure options proposed by Duke Energy for the CCR surface
impoundments at the Allen facility. The purpose of this evaluation was to determine which
closure option or options may be incorporated into an approvable Closure Plan under CAMA.
DEQ elects the provisions of CAMA Option A that require movement of coal ash to an
existing or new CCR, industrial or municipal solid waste landfill located on -site or off -site for
closure of the Active Ash Basin and the Retired Ash Basin at Allen 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 Allen is more protective than leaving the material in place. DEQ determines
that CAMA Option A is the most appropriate closure method because removing the primary
source of groundwater contamination will reduce uncertainty and allow for flexibility in the
deployment of future remedial measures.
DEQ does not elect CAMA Option B for the CCR surface impoundments at Allen. 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 Allen.
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
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 6

based on the current geographic scope and vertical extent of the groundwater contamination
plume, and the modeled extent of the plume in the future, DEQ does not believe these two
closure options can meet the requirements of CAMA Option B for the CCR surface impoundments
at Allen.
DEQ does not elect CAMA Option C (i.e., closure under the federal CCR Rules found in 40
CFR Part 257) for the CCR surface impoundments at Allen. 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. §§ 27913-2 & 143-211) and the General Assembly's mandate under CAMA that
DEQ ensure that any Closure Plan, which must incorporate an approvable closure
option, is protective of public health, safety, and welfare, the environment, and
natural resources (see N.C. Gen. Stat. § 130A-309.214(b) & (c)).
c. For the CCR surface impoundments for which the closure option(s) must be
determined, CAMA Option A provides a better CAMA mechanism for ensuring State
regulatory oversight of the closure process than Option C, as well as greater
transparency and accountability.
d. While the federal CCR Rule was written to provide national minimum criteria for CCR
surface impoundments across the country, CAMA was written specifically to address
the CCR surface impoundments in North Carolina.
e. While the federal CCR Rule allows CCR surface impoundment owners to select closure
either by removal and decontamination (clean closure) or with a final cover system
(cap in place), EPA anticipates that most owners will select closure through the less
protective method of cap in place.
f. There is considerable uncertainty regarding the status and proper interpretation of
relevant provisions of the federal CCR Rule. For instance, EPA is reconsidering
portions of the federal CCR Rule. Also, the performance standards in 40 CFR
257.102(d) for cap in place closure are the subject of conflicting interpretations (and
possible litigation) among industry and state authorities.
VI. Conclusion
The final closure plan is due on August 1, 2019 in accordance with this determination.
Based on DEQ's evaluation of the options submitted by Duke Energy, DEQ elects the provisions
of CAMA Option A that require movement of coal ash to an existing or new CCR, industrial or
municipal solid waste landfill located on -site or off -site for closure of the Active Ash Basin and
the Retired Ash Basin at Allen 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.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 7

ATTACHMENT A
DEQ EVALUATION OF CLOSURE IN PLACE AND HYBRID OPTIONS BASED ON
GROUNDWATER MONITORING AND MODELING DATA
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 8

DEQ EVALUATION OF CLOSURE IN PLACE AND HYBRID OPTIONS BASED ON
GROUNDWATER MONITORING AND MODELING DATA
Groundwater Monitoring Summary
As DEQ considered the closure options presented by Duke Energy, DEQ evaluated
whether the closure in place or the hybrid options met the requirement for CAMA Option B.
Specifically, DEQ attempted to determine whether the design would prevent any post -closure
exceedances of groundwater standards beyond the compliance boundary upon full
implementation of the closure plan. Significantly, the contaminated groundwater plume has
already extended beyond the compliance boundary in a portion of the CCR surface
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 Allen Steam Station January 2018 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 from west to east and discharges to the Catawba River (Lake
Wylie). 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 and strontium concentrations are fairly widespread in the bedrock flow layer. There
are isolated occurrences of boron, cobalt, iron, and molybdenum within and downgradient of the
ash basins.
DEQ concludes that the contaminated groundwater plume has extended beyond the
compliance boundary along the eastern edge of the property on the shore of Lake Wylie. Based
on Figure ES-1, this plume extends along the entire length of the RAB and AAB.
II. 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
2: 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
standards at the compliance boundary upon full closure implementation. Cross sections A -A' and
B-B' 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.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 9

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=120 years
• upon completion of the hybrid option at t=0 years
• hybrid option at t=120 years
The tables below summarize the results from the model simulations. The boron
concentrations depicted in each table represent the maximum boron concentration in any layer
(ash, saprolite, transition zone, and bedrock) of the model. The 4,300-foot wide contamination
plume depicted in the table spans the entire length of both ash basins, the retired ash basin and
active ash basin. The cross sections are cut along the active ash basin dam (A -A' along the
northern portion and B-B' along the southern portion).
Allen Modeling Results for Cross -Section A -A'
Model Simulation
Maximum Concentration
Depth of GW
Width of
of Boron Above 2L (ug/L)
Contamination Above 2L
Contamination Plume
Beyond Compliance
(feet bgs) Beyond
(feet) Beyond
Boundary
Compliance Boundary
Compliance
Boundary
Current Conditions
700-4,000
120
4300
Completion of Final
700-4,000
20
4300
Cover (t=0 yrs)
Final Cover
700-4,000
70
2000
(t=120 yrs)
Completion of
700-4,000
140
4300
Hybrid (t=0 yrs)
Hybrid (t=120 yrs)
700-4,000
9S
2400
bgs — below ground surface
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 10

Allen Modeling Results for Cross -Section B-B'
Model Simulation
Concentration of Boron
Depth of GW
Width of
Above 2L (ug/L) Beyond
Contamination Above 2L
Contamination Plume
Compliance Boundary
(feet bgs) Beyond
(feet) Beyond
Compliance Boundary
Compliance
Boundary
Current Conditions
700-4,000
95
4300
Completion of Final
700-4,000
100
4300
Cover (t=0 yrs)
Final Cover
700-4,000
85
250
(t=120 yrs)
Completion of
700-4,000
155
4300
Hybrid (t=0 yrs)
Hybrid (t=120 yrs)
700-4,000
85
2400
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 120 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.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 11

Figure ES-1: Allen Steam Station January 2018 CSA Update Report
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ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 12

Figure ES-1 Legend: Allen Steam Station January 2018 CSA Update Report
LEGEND
AREA OF CONCENTRATION IN GROUNDWATER
ABOVE NC2L (SEE NOTE 5)
AREA OF CONCENTRATION IN G ROUNDWATER ABOVE NC2L
POTENTIALLY ATTRIBUTABLE TO THE COAL PILE (SEE NOTE 6)
ASH BASIN WASTE BOUNDARY
APPROXIMATE LANDFILL WASTE BOUNDARY
GENERALIZED GROL)NDWATER FLOW DIRECTION
WATER SUPPLY WELL LOCAT 10N
STREAM WITH FLOW DIRECTION
---- DUKE ENERGY PROPERTY BOUNDARY
NOTE:
1. OCTOBER, 2016 AERIAL PHOTOGRAPF+Y OBTAINED FROM GOOGLE EARTH PRO ON
DECEMBER 7. 2017. AERIAL DATED OCTOBER 8. 2016.
2. STREAMS OSTAJNED FROM AM EC FOSTER WHEELER NRTR, MAY 2015_
3_ GENERALIZED GROUNDWATER FLOW DIRECTION BASED ON SEPTEMBER 11. 2017
WATER LEVEL DATA.
4. PROPERTY BGUNDARY PROVIDED BY DUKE ENERGY_
5. GENERALIZED AREAL EXTENT OF MIGRATION REPRESENTED BY WAC 02L
EXCEFDANCES OF MULTIPLE CONSTITUENTS (BORON AND ARSENIC) IN MULTIPLE
FLOW ZONES_
6. GENERALIZED AREAL EXTENT OF MIGRATION REPRESENTED BY WAC 02L
EXCEFDANCES OF MULTIPLE CONSTITUENTS (BERYLLIUM, NICKEL, SULFATE -AND
THALLIUM) IN MULTIPLE FLOW ZONES_ A SEPARATE. ASSESSMENT IS PLANNED FOR
THE COAL PILE ARIEA.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 13

ALLEN CURRENT CONDITIONS IN 2018
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
ie
0
0_
m
0_
0
3
v
0
c
0
Q
v
r
v
fD
F'
0
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 14

ALLEN UPON COMPLETION OF FINAL COVER IN 2030, t = C
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
�yVy
1
INN
0
f, 1.
■
■
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0
0-
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0-
0
v
0
D
Q
�7
r-
v
77
rD
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 15

ALLEN FINAL COVER IN 2150, t = 120 years
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
L 0
I Q
IL
,f
■
■ ■•■ FNo
■■ I I
No 0
1 �
y ■" �..,
k y f ■
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 16

ALLEN UPON COMPLETION OF HYBRID IN 2030, t =
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
3
MLLr-ry I,LOSURE DETERMINATION - APRIL 1, 2019 -If

ALLEN HYBRID IN 2150, t = 120 years
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
r
v
m
7
fD
_OSURE DETERMINATION - APRIL 1, 2019 - 18

ALLEN CURRENT CONDITIONS IN 2018
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
A compliance 1
boundary A
dam 1
1
7t 1 Lake
{Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 19

ALLEN UPON COMPLETION OF FINAL COVER IN 2030, t = 0
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
A compliance A of
boundary
I
drain dam ! Lake Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 20

ALLEN FINAL COVER IN 2150, t = 120 years
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
A compliance A of
boundary
draindam ;Lake Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
It
i
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 21
r
L

ALLEN UPON COMPLETION OF HYBRID COVER IN 2030, t = 0
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance J
A . boundary A
dam
Lake Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 22

ALLEN HYBRID IN 2150, t = 120 years
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
compliance J
A . boundary A
dam
Lake Wylie
0
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 23

ALLEN CURRENT CONDITIONS IN 2018
CROSS SECTION B-B' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
B compliance B'
boundary
drain 0
i Lake Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 24

ALLEN UPON COMPLETION OF FINAL COVER IN 2030, t = C
CROSS SECTION B-B' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
Bcompliance B 1P boundary
dam 1
1 1 Lake Wylie
Allen model layers: 1_
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 25

ALLEN FINAL COVER IN 2150, t = 100 years
CROSS SECTION B-B' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
B compliance B
boundary
dam
Lake Wylie
Allen model layers:.�� ,
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 26

ALLEN UPON COMPLETION OF HYBRID COVER IN 2030, t = 0
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
B boundary B
drain
dam Lake Wylie
Allen model lavers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
i
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 27

ALLEN HYBRID IN 2150, t = 120 years
CROSS SECTION A -A' (VIEWED FROM SOUTH SIDE OF CROSS SECTION LOOKING NORTH)
MAX BORON ANY LAYER green = 75-700, tan = 700-4000, red = 4000-10,000, blue = 10,000-40,000
compliance
B boundary B
drain
dam' Lake Wylie
Allen model layers:
Ash 1-11
Saprolite 12-14
TZ 15-16
Bedrock 17-26
Vertical
exaggeration X 3
A -A' —820 ft
B-B' —730 ft
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 28

ATTACHMENT B
RESPONSE TO COMMENTS
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 29

RESPONSE TO COMMENTS
I. Summary of Responses to Comments
DEQ received approximately 1,090 comments regarding the four Allen closure options.
The overwhelming majority of comments (approximately 960) were submitted via a form email
that supported closure by excavation and removal to a new onsite landfill or, alternatively,
excavation and removal to an offsite landfill. The email commenters requested that the coal ash
be removed from leaking, unlined pits and moved to dry lined storage away from waterways and
groundwater. The commenters, however, did not specifically distinguish between moving the
coal ash to a new onsite landfill or removal to an offsite landfill. Two other commenters
specifically recommended moving the coal ash to a new onsite, lined landfill. Only one
commenter specifically requested closure -in -place. A discussion of these and other related
comments follows.
II. Detailed Responses to Comments
A. Closure -in -place.
Comment: Only one commenter supported the closure -in -place option. The concern
with excavation involved potential dump truck traffic along South Point Road associated with
removal activities.
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.
B. Hybrid
There were no comments that directly addressed the hybrid option.
C. Closure by removal to new onsite landfill.
Comment: As referenced in the "Summary of Responses to Comments" section above,
the overwhelming majority of commenters stated in a form email that they were supportive of a
closure option which could conceivably include either closure option four or five - closure by
removal to a new onsite landfill or, alternatively, removal to an offsite landfill. The comment
language in that form email states the following:
"Dear Coal Ash Comment Administrator North Carolina DEQ: Allen,
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!
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 30

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: 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 impoundment at Allen 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.
Comment: A commenter urged that the most cautious approach to coal ash management
"means complete removal and placement in a lined facility as near as possible to its current
location." The commenter further pointed out that the other options all leave at least some ash
in place - a continuation of the original problem which has uncertainty as a long-term viable
option. The commenter suggested that evaluation of the potential re -uses of ash such as in
roadbeds and an aggressive program of marketing re -use to other jurisdictions.
Response: 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.
Comment: Two commenters from the River Lakes neighborhood next to Camp Lakes
believed that contaminated water is currently flowing into their home and that they deserve
access to clean city water. The commenters suggested a four -lane extension of N.C. Highway 273
across the Catawba River which would save both Duke Power and the North Carolina Department
of Transportation (NCDOT) considerable amount of money and time in accessing the site. The
commenter suggested an onsite temporary concrete plant that could be utilized to encapsulate
coal ash into construction resulting in a large reduction in trucking costs versus moving all coal
ash offsite. The commenter further suggested there would be significant material savings to
NCDOT using ash as road fill material. The commenters also suggested the possibility of shared
construction costs to allow partial disposal using construction and partial entombing of the
remaining waste in the lined concrete base of the elevated structure.
Response: DEQ agrees that Duke Energy should evaluate the potential of coal ash for
other approved product uses as described in the response to comment ii. above.
D. Closure by removal to an offsite landfill.
Comment: The overwhelming majority of commenters stated in a form email that they
were supportive of a closure option which could conceivably include either closure option four
or five - closure by removal to a new onsite landfill or, alternatively, removal to an offsite landfill.
Reference is made to the specific comment language in paragraph 4i. above.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 31

Response: DEQ agrees and references the response to the comment in paragraph 4i.
above.
Comment: One commenter who attended the January 17, 2018, Sherrill's Ford
Elementary School meeting stated that Duke Energy needs to remove the coal ash completely
from its leaking, unlined pits.
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.
Comment: Another commenter, citing to a recent New York Times article ["Data collected
by the federal Environmental Protection Agency found that 95 percent of them (unlined coal ash
ponds) had leaked, seeping into rivers and groundwater supplies"] rejected the capping proposal
and indicated that Duke Energy needed to remedy its own mistakes and remove the coal ash
from its current unlined locations, then relocate it to lined landfills.
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.
Comment: A commenter stated the saltstone method of disposal would isolate this
hazardous waste for safe and permanent storage. Moreover, Duke Energy should store the coal
ash on their own property, and not be allowed to move it across our state as they have in the
Moncure area. The commenter also added that coal ash should not be capped in place.
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. The saltstone method of disposal,
utilized by the U.S. Department of Energy for isolating hazardous and radioactive waste at a
defense nuclear facility in South Carolina, is not permissible under CAMA.
Comment: A commenter who attended the public hearing at Stuart Cramer High School,
in rejecting the closure -in -place option, believed that the only acceptable option for dealing with
this waste involved excavating all coal ash at the Allen site and moving it to lined containers.
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.
Comment: A researcher who witnessed the aftermath of the largest coal ash spill in the
country in 2008 insisted that NCDEQ should require Duke Energy to remove its coal ash from its
leaking, unlined impoundments and move it to dry lined storage. There were also concerns for
protecting the Catawba River and downs stream rivers.
Response: Potential coal ash releases are a significant concern for DEQ and underscore
the decision to require Duke Energy to excavate and remove all coal ash from impoundments at
the Allen site.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 32

Comment: A commenter stated coal ash stored at the Allen Stream Station should be
completely removed and safely stored away from a major water source that thousands drink
from.
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.
Comment: Another commenter expressed serious concern regarding the closure -in -place
option and provided lengthy commentary on why this option was not viable:
"Cap -in -place is unacceptable for any of the coal ash sites in North Carolina. Any
'solutions' proposed by Duke Energy that do not excavate and move ash to fully lined,
scientifically designed systems that fully encapsulate coal ash must be rejected. Without
multiple, sealed bottom, side, and top liners, North Carolina's groundwater will always be at risk.
Due to increases in extreme weather, more frequent hurricanes and massive rainstorms,
groundwater models of 100 or 500-year floodplain are obsolete. Given the unpredictable
fluctuations in the water tables and groundwater flows, there is no way that surface capping
without properly engineered underlying bottom liners can protect groundwater in the coming
decades."
The commenter continued by stating: "DEQ should require Duke Energy's new landfills to
go beyond the minimal mandatory protections provided by current regulations. DEQ must carry
out independent studies and obtain recommendations for the best liner technologies, redundant
liners, and with multiple long-term safeguards. Scientifically based placements for baseline and
ongoing groundwater monitoring wells should be established. These must be thoroughly and
constantly monitored — with full, public, transparent, internet accessible, easily available data
from the monitoring results. Ground water and surface monitoring should be ongoing for a
minimum of 50 years ... While transporting existing coal ash dumps away from rivers and
floodplains is essential, every effort should betaken by DEQ to ensure that the distances coal ash
is moved is minimized and that the coal ash destinations are always kept on Duke Energy's
property.
The commenter concluded: "Once constructed, these new lined landfills should represent
the best technologies and materials available — not materials that create short-term financial
savings. The original existing dumps were disasters for public health, for NC communities, and
for our state's waters. We have this one chance to remediate some of the damages and most
importantly, to safeguard future generations from heavy metal coal ash contamination. Our
state-wide re -design of storage systems for millions of tons of coal ash must be done right this
time."
Response: 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.
Comment: One commenter, who could not attend one of the Allen site meetings,
submitted a comment stating that ground water seepage from cap in place along with potential
for natural disasters make the existing locations of coal ash pits a disaster waiting to happen. The
commenter continued by stating that best practices are known and have been implemented in
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 33

other states by removing the ash to a secure, lined location, where natural disasters can be
withstood and implemented quickly before the next spill occurs.
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.
Comment: Another commenter, in requesting that all ash lagoons in North Carolina be
relocated to 60-millimeter plastic lined landfills, joined in rebuffing closure -in -place: "There are
plenty of technical points that argue against your cap in place plan. The most significant to me
are that the ponds have been built over stream beds. Even if capped, erosion from the stream
flow that travels under the lagoons will continue to carry toxic metals into the river. The site is
60 years old, it's already leaking, Allen's dams have failed before and over 114,000 people rely
on drinking water intakes immediately downstream. With the ash stacked 75 feet high on the
banks of the river I'm worried about a hurricane, earthquake, or 100-year flood that could lead
to dam failure."
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.
Comment: A commenter opined that Duke Energy should be required to move the coal
ash to a safe storage facility off of the Allen Plant location - capping and storing the coal ash at
Allen in place and in an unlined basin is not a viable solution because this option will not protect
the ground water table and Lake Wylie from the heavy metals that are leaching out of the existing
coal ash basins.
Response: DEQ agrees with this comment that coal ash must be excavated and removed
from the Allen site impoundments under CAMA Option A requiring movement of coal ash to an
existing or new CCR, industrial or municipal solid waste landfill located on -site or off -site for
closure.
Comment: One commenter who attended the public hearing at Cramer High School
believes that any solution other than excavation and removal of coal ash stored on the property
of the Allen steam station is unacceptable. The commenter, focusing on the toxicity and health
effects of coal ash, concluded by stating that Duke Energy must excavate and remove the coal
ash to an area where it will minimally affect human health and environmental safety.
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.
Comment: Another commenter who spent many years researching coal ash
contamination stated that unlined ash pits pose threats to public health and environmental
quality, even when water is drained and the basin is capped in place. The concern is that toxic
metals and other compounds associated with coal ash would still be present without any liner
after the basin is drained, and could therefore still leach into the nearby aquifer, affecting well
water and surface water nearby. The commenter urged not to allow capping in place of ash at
this or any other site in North Carolina.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 34

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.
Comment: Similarly, another commenter expressed support for the full excavation of
both the Allen and Marshall sites by Duke Energy. The commenter felt that capping the ash in
place will continue to contaminate the groundwater and discharge pollutants into Lake Norman
and Lake Wylie - with the only safe solution a complete excavation and either recycling or storage
in lined landfills.
Response: DEQ agrees that the coal ash must be excavated and removed from the Allen
site impoundments.
Comment: A related comment from the Cramer High School meeting echoed those
sentiments — the commenter stated that the pits should be excavated as soon as possible to the
maximum safe extent with at least twenty-five (25) percent recycled through encasement in
cement bricks, concrete and other methods. The remainder of excavated ash should be moved
into double -lined landfills away from rivers, lakes and aquifers with monitored leak detection
systems. The double -lining would include 2' of clay on the exterior with a durable lining
impervious to water.
Response: DEQ agrees with this comment that coal ash must be excavated and removed
from the Allen site impoundment under CAMA Option A requiring movement of coal ash to an
existing or new CCR, industrial or municipal solid waste landfill located on -site or off -site for
closure.
Comment: A small number of other commenters also suggested the material should be
recycled into concrete.
Response: 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.
Comment: Another commenter suggested using coal ash for construction materials to
build or improve South Point Road and/or Parkway Bridge to 1-485.
Response: DEQ agrees that Duke Energy could evaluate the potential of coal ash for other
approved product uses.
Comment: DEQ received multiple comments opposing capping in place that stated
general support for closure by excavation [removal] to dry, offsite lined landfills on property
owned by Duke to keep coal ash away from drinking water and recreational water uses near the
Catawba, Wateree, Santee and Cooper Rivers and associated chain of lakes including Lake Wylie
and the Lake Norman area.
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.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 35

Comment: A former federal wildlife biologist provided extensive commentary concerning
excavation and removal: "I respectfully request that The North Carolina Department of
Environmental Quality (NCDEQ) require Duke Energy to remove its coal ash from the existing
unlined storage pits at the Allen Steam Station location. The excavated coal ash should then be
moved to a dry, lined storage -landfill on Duke Energy property, as detailed in Option #5 of their
Allen Steam Station Ash Basin Closure Options Analysis. The existing Allen Ash Basins location is
directly adjacent to the Catawba River/Lake Wylie waterways, where groundwaters must be
transporting coal ash pollutants (arsenic, beryllium, cadmium, cobalt, lithium, thallium, etc.)
directly into those waters ... I am concerned about the potential for existing water quality
degradation and the lack of existing surface water monitoring efforts by NCDEQ in the Allen
Steam Station vicinity to document such degradation. Concentrations of coal -ash -related
chemicals are known to have negative health impacts on both humans and fish/wildlife residents
exposed to them. Removal of those coal ash health hazards from the Allen Ash Basins facility is
essential to those residents' health and well-being and is a solution supported by historical,
national clean-up efforts (Superfund sites, etc.)." The commenter also raised several questions
regarding ground and surface water pollution and suggested additional testing and monitoring
activities.
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.
Comment: One commenter suggested use of a coal train to expedite the removal process
and limit the amount of trucking needed to lessen impact on roads.
Response: The Duke Energy Allen site closure plan will likely assess the viability of the
various transport options for coal ash excavated from the Allen impoundments.
Comment: Some commentators also suggested that Duke Energy intentionally
overestimated trucking traffic concerns related to removal to support a closure -in -place solution.
Response: DEQ takes no position with the suggestion that Duke Energy intentionally
overestimated trucking traffic concerns.
Comment: A commenter representing the Catawba Riverkeeper Foundation,
MountainTrue, and Waterkeeper Alliance submitted extensive written comments urging DEQ to
require the Allen coal ash basins to be excavated to a lined landfill to protect the environment
and human health.
The commenter claimed coal ash impoundments at Allen are not eligible for closure -in -
place under CAMA. The commenter alleged that closure -in -place violates the North Carolina
groundwater rule. The commenter sets out several arguments it believes supports that claim: 1)
Duke Energy's modelling demonstrates it will not meet groundwater standards if it chooses
closure -in -place; 2) Duke Energy's modelling underestimates the extent of contamination; 3)
Duke Energy tested groundwater compliance at the wrong location; 4) the groundwater rule
prohibits closure -in -place because the coal ash will contribute to violations of the groundwater
standard for centuries; and 5) closure -in -place is unavailable because it will not restore
groundwater to the legal standard.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 36

The commenter next claimed that coal ash impoundments at Allen are not eligible for
closure -in -place under the Coal Combustion Residuals (CCR) rule. The commenter alleged that:
1) the CCR rules' performance standards require separating ash from the groundwater and
precluding its future impoundment; and 2) the CCR rules' corrective action requirements
preclude closure -in -place.
The commenter continues by asserting that DEQ must base its closure determination on
effectiveness and not cost to the polluter. The commenter further maintains that DEQ should
reject Duke Energy's "Community Impact Analysis." The commenter claims that Duke's Energy's
report downplays well -established pollution risks and exaggerates the impact on communities of
excavating and trucking material to offsite landfills. Further, they claim that diesel emissions do
not meaningfully distinguish between closure methods and that the report's habitat analysis is
flawed. The commenter concludes by questioning the validity of Duke Energy's closure options
scoring system - and offers its own analysis to demonstrate why it believes Duke Energy
manipulated scores to suit a desired outcome.
Response: 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 impoundment at Allen in accord with N.C. Gen. Stat. § 130A-309.214(a)(3).
Comment: The same commenter requested that DEQ ignore a Duke Energy report on
estimated greenhouse gas emissions associated with various closure options for the six
unresolved coals ash sites (including the Allen site). The commenter claimed DEQ should
disregard this submission because it was made after DEQ's deadline for Duke Energy to submit
its materials and outside the public comment period, thereby denying the public an opportunity
to respond to it. DEQ should also disregard this submission because it is irrelevant to the decision
facing DEQ, which is to select a closure method that stops the ongoing pollution and continuing
threat to our water resources posed by Duke Energy's leaking coal ash basins.
Response: 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 impoundment at Allen in accord with N.C. Gen. Stat. § 130A-309.214(a)(3).
Comment: A commenter from DEQ's Environmental Justice and Equity Board rejected
the closure -in -place option in support of excavation and movement into lined landfills: "There is
no way to safeguard the health of North Carolinians while leaving harmful toxins to leach into
our ground and water. Furthermore, the long-term costs of leaving toxic coal ash in pits alongside
our lakes and rivers under a 'cap in place' option, would far outweigh the cost of scientifically
sound excavation to lined landfills on Duke's property. This includes maintenance costs, future
liability costs, and the too often non -considered cost of human capital when disasters, such as
the 2014 Dan River spill, occur."
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.
Comment: A variety of comments were received in the form of YouTube testimonials
following DEQ's Environmental Justice Advisory Board meeting in Wilmington, NC, and from
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 37

other entities and individuals regarding the impact of coal ash spills. Links to each these
testimonials follow:
Caroline Armijo - ACT Member https://youtu.be/ciag3oPl4gU
Johnny Hairston - resident in harm's way of basin failure https://youtu.be/6iK1sbVO058
Rev. Gregory Hairston — leader/resident in close proximity https://youtu.be/IV9crtEyTJY
John Wagner - ACT Member https://youtu.be/IV9crtEyTJY
Frank Holleman - lead attorney of SELC https://youtu.be/elwPWPYb3Uc
At What Cost (2014) https://youtu.be/rraUoadgr8o
Danielle Bailey -Lash on CNN https://youtu.be/OCTU-CUoQzQ
A Time to Sing (Abridged) (August 2018) https://youtu.be/HQFYKBaf4NQ
A Day of Prayer (February 2019) https://youtu.be/agRzScT BEs
Response: 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 impoundment at Allen in accord with N.C. Gen. Stat. § 130A-309.214(a)(3).
Comment: A commenter who also serves as an elected official stated that sites containing
coal ash should not be capped where they are, since groundwater is invaded by the toxins
requiring maintenance and monitoring — toxins that would ultimately end up in surface waters
through seepage or breaches. The commenter opined that coal ash be stored in lined landfills
which meet federal guidelines. The commenter also had concerns regarding leaching from
concrete if the coal ash is mixed into any building materials.
Response: 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 impoundment at Allen in accord with N.C. Gen. Stat. § 130A-309.214(a)(3).
Comment: A former North Carolina state legislator submitted comments stating that
Duke Energy has investigated numerous options for the safe disposal of coal ash as highlighted
in the Duke Energy Coal Combustion Product Management Study Phase 3 (May 2016). The
commenter believed that Section 2-4 ("Masonry Units") of the study can be applied at the Allen
Plant and that Duke Energy has investigated all the options in this report. The commenter
referenced direction from the General Assembly in the form of CAMA III or CAMA IV. The
commenter points out that a company, Nu -Rock, has a long history of using coal ash in cement
products and that Nu -Rock's domestic headquarters is in Charlotte. The commenter believes this
is a viable option that has been investigated by both the University of North Carolina (Charlotte)
and Virginia Tech University.
Response: 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 impoundment at Allen in accord with N.C. Gen. Stat. § 130A-309.214(a)(3).
Comment: Several dozen South Carolina residents submitted comments. Many live in the
Catawba-Wateree waterway chain. The overwhelming consensus from these comments is to
remove coal ash from unlined pits at Allen and move the ash to an area that is safer that will not
impact water drawn or used in the Catawba-Wateree chain.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 38

Response: DEQ agrees that coal ash at Allen should be removed from impoundments and
placed in a lined landfill. 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.
Comment: Two commenters responded by telephone voice message. One commenter
was concerned that NCDEQ would chose the least expensive option of capping -in -place. The
commenter stated that full evacuation of all coal ash sites, the most protective option, should be
chosen for all sites. The second commenter, who lives in Gaston County, stated that there is
arsenic and hexavalent chromium (and other contaminants) in the well water and that NCDEQ
should fully excavate the coal ash since it can sell to concrete companies to make concrete.
Response: DEQ agrees that coal ash at Allen should be removed from impoundments and
placed in a lined landfill. 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.
ALLEN CLOSURE DETERMINATION - APRIL 1, 2019 - 39

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.
Page 1 of 4

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

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

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