NC0001422_5-Sutton GAP DENR Approval 2_6_2015_20150805

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North Carolina Department of Environment and Natural Resources
Pat McCrory
Governor
February 6, 2015
Mr. Harry Sideris
Senior Vice -President
Environment, Health, and Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, NC 28202
Re: L.V. Sutton Energy Complex
NPDES Permit No. NC0001422 — New Hanover County, North Carolina
Conditional Approval of Revised Groundwater Assessment Work Plan
Dear Mr. Sideris:
Donald R. van der Vaart
Secretary
On December 31, 2014, the Division of Water Resources (Division) received the revised
Groundwater Assessment Plan (GAP) for the above listed facility. The revised GAP was submitted
in response to the Division's Review of Groundwater Assessment Work Plan letter dated November
4, 2014 regarding requirements of the Coal Ash Management Act 2014—G.S.130A-309.209(a). A
review of the plan has been completed and several deficiencies or items requiring clarification were
noted. In order to keep the site assessment activities on a timely schedule, the Division has approved
the revised Groundwater Assessment Plan under the condition that the following deficient items are
addressed in the Groundwater Assessment Report:
• Comment Section 7. 1. Subsurface Exploration:
The present version of the GAP does not provide any description of how the confining unit
will be evaluated as directed in General Comment #3 of the Division's Review of
Groundwater Assessment Work Plan letter dated November 4, 2014. In order to refine the
conceptual model at the site, install an adequate amount of borings to delineate the extent and
thickness of the confining unit. In addition, conduct tests to evaluate the vertical gradient
across the confining unit.
• Comment Section 7.2 Ash Pore Water and Groundwater Sampling and Analysis:
Text on pages 41 and 42 refers to proposed sampling for radium at wells MW-44SA and
BW -2S, which are not listed in tables or maps. Clarify this situation before sampling or
chose alternate sampling locations that can be documented.
1636 Mail Service Center, Raleigh, North Carolina 27699-1636
Phone: [phone] Internet: http://www.ncwater.org
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• Comment Section 7.3.1 Water Quality Samples:
Timing of stream sampling should be conducted with consideration of the tidal influence on
the Cape Fear River in this area which is a transition zone between the riverine and estuarine
environment (e.g. upstream samples should be taken during an outgoing tide to be more
representative of upstream river conditions).
In addition, technical direction that will serve as the basis of expectations for completion of the site
assessment are provided at Attachment 1. Failure to address the deficient items stated above will
result in Duke Energy not being in compliance with the stated statutes. Per G.S. 130A -309.209(a)(3)
and (4), you must begin implementation of the revised GAP on February 16, 2015 and the
Groundwater Assessment Report is due on August 5, 2015. It is our understanding that Duke
Energy may have to obtain additional permits to facilitate installation of certain monitoring wells. In
the event permits are needed for this purpose, Duke Energy should take all steps necessary consistent
with the law to avoid delaying completion of the assessment report.
If you have any questions, please contact Geoff Kegley at [phone].
Sincerely,
S. Ja ti erman, P.G., Acting Director
Division of Water Resources
cc: WQROS — WiRO
WQROS Central Files
DENR Secretary - Don van der Vaart
Synterra (Attn: Kathryn Webb) —148 River Street, Suite 220, Greenville, SC 29601

Attachment 1
Page 1 of 6
Duke Energy GAP Review Issues
The items identified in this Groundwater Assessment Plan (GAP) review summary are provided for
general discussion for the various parties to agree upon technical direction and content in the revised
GAPs, comprehensive site assessments (CSAs), and corrective action plans (CAPS).
Groundwater Monitoring
1. A schedule for continued groundwater monitoring is mandated by the Coal Ash Management
Act 2014. An interim plan should include at least two rounds of groundwater samples collected
and analyzed in 2015. The analytical results of the first round of data collected in 2015 would be
included in the CSA report, while the results of the second round would be submitted as a CSA
addendum. After CSA data can be evaluated, a plan for continued groundwater monitoring can
be developed for implementation in 2016.
2. Sites impacted by inorganics are typically managed using a tiered site analysis which includes
four elements as referenced in EPA/600/R-07/139:
• Demonstration of active contaminant removal from groundwater, & dissolved plume
stability;
• Determination of the mechanism and rate of attenuation;
• Determination of the long-term capacity for attenuation and stability of immobilized
contaminants, before, during, and after any proposed remedial activities; and
• Design of performance monitoring program, including defining triggers for assessing
the remedial action strategy failure, and establishing a contingency plan.
This reference and the framework described above should be used as applicable to meet
the corrective action requirements found in 15A NCAC 02L.0106.
3. Because of uncertainty concerning the site's ability to attenuate contaminants over the long
term given potentially changing geochemical conditions, there is a need to address the elements
of the tiered site analysis described above and collect appropriate samples as part of the CSA,
CAP development, and continued groundwater monitoring.
4. The Division of Water Resources (Division) Director is responsible for establishing background
levels for COPCs in groundwater. This determination is based on information and data provided
by the responsible party and may include formal statistical testing using background wells with
at least four rounds of data. Wells identified as "background" are subject to periodic review
based on a refined understanding of site chemistry and hydrogeologic conditions. In general,
each facility must have a background well or wells screened or open to each of the dominant
flow systems that occur at the site and are associated with groundwater contamination. Any
questions concerning adequacy of background monitoring locations or conditions at the
facilities should be directed to the Regional offices.

Attachment 1
Page 2 of 6
5. Delineation of the groundwater contaminant plume associated with coal combustion residuals is
a requirement of the investigation and if off-site monitoring wells are ultimately required to
perform this task, then it is expected that these activities will be completed as part of the
groundwater assessment activities and included in the final report. Documentation of the effort
to gain off-site access, or right of way permits, will be provided if off-site access is denied or
alternate means of assessing the area were not available within the allocated timeframe (such
as within right-of-ways).
Site Assessment
Data Requirements and Sampling Strategy
1. Robust data collection is warranted to support timely completion of site assessments and
subsequent corrective action plans because of the impending deadlines for completion of CSAs
and CAPS, scale and geologic complexity of the sites, the challenges of modeling heterogeneous
systems, and site proximity to potential human and sensitive ecosystem receptors.
2. Robust data collection will be focused along strategically positioned flowpath transect(s) - from
ash pond source to potential receptor—as an efficient approach for model development
(analytical, geochemical, groundwater flow, and transport) in support of risk assessment and
CAP development. Data collected to support evaluation of site conditions along the flowpath
transects should be located along or defensibly proximate to the modeled transects.
3. The dataset developed along proposed flowpath transects will include any information needed
to determine constituent concentrations, conduct Kd tests, and perform batch geochemical
modeling in multiple flow horizons as appropriate. This data will include a) solid phase sample
collection for Kd measurement and batch geochemical modeling, inorganic analysis and
speciation, and other parameters identified in General Comment #4 of the November 4, 2014
GAP comments issued by DWR, b) solution phase sample collection for total and dissolved
inorganic analysis of total concentrations, small pore filtration for dissolved samples, etc., and c)
slug, constant/falling head, and packer testing. The solid phase sample mineralogy, total
concentration results, re-dox measurements, and other geochemical parameters will be used as
input for equilibrium speciation calculations of redox sensitive constituents calculated by
PHREEQC or similar program (EPA/540/5-92/018). This geochemical modeling will be performed
to identify potential mineral phases, estimated species speciation and concentrations, and will
be performed varying key solubility controlling parameters to predict mineral phases,
speciation, and concentrations under varying conditions. Solid samples for Kd tests from
locations where moderately to strongly reducing conditions are anticipated shall be frozen upon
collection and tested in glove box conditions (EPA/600/R-06/112). Refer to EPA/600/R-07/139
Section III for the data collection and characterization needed to support the four -tiered analysis
discussed above.
4. Speciations for groundwater and surface water samples should include Fe, Mn, and any COPCs
whose speciation state may affect toxicity or mobility (e.g. As, Cr, Se, or others if applicable).
This speciation will apply for groundwater samples collected at wells located along proposed

Attachment 1
Page 3 of 6
flowpath transects and in wells where these constituents exceed 2L groundwater standards as
well as for surface water samples collected within ash impoundments.
5. Solid phase samples shall be analyzed for: minerals present, chemical composition of oxides,
hydrous Fe, Mn, and AL oxides content; moisture content; particle size analysis; plasticity;
specific gravity; porosity; permeability, or other physical properties or analyses needed to
provide input to a chosen model. The Division reserves the right to request analysis for organic
carbon content, organic carbonate content (as appropriate if site conditions warrant), or ion
exchange capacities, if needed to complete the site assessment process.
6. In addition to conducting the SPLP leachable inorganic compounds analysis for selected ash
samples to evaluate the potential for leaching of constituents to groundwater, the leachable
analysis should also be conducted for some soil samples from locations beneath the ash ponds,
within the plume, and outside the plume to evaluate potential contributions from native soils.
7. In addition to collecting solid phase samples onsite for Kd procedures, soil samples should be
also collected from unaffected soils within groundwater flow pathway to evaluate Kd(s) or
hydrous ferrous oxide.
8. Rock samples for laboratory analyses should be collected as commented in General Comment 4
of the November 4, 2014 GAP comments issued by DWR. This GAP review comment indicated
that the sample(s) collected from bedrock well soil and rock cores shall be analyzed, at a
minimum, for the following: type of material, formation from which it came, minerals present,
chemical composition as oxides, hydrous Fe, Mn, and Al oxides content, surface area, moisture
content, etc.; however, these analyses were not mentioned in the GAP. The Division reserves
the right to request analysis for organic carbon content, organic carbonate content, and ion
exchange capacity if needed to complete the site assessment process.
9. The coal ash and soil analyte lists should match the groundwater analyte lists.
10. Total uranium analysis should be analyzed where total radium is analyzed for groundwater.
11. If analytical results from a seep sample exceed 2L standards, then the area in the vicinity of the
sample location should be investigated for groundwater contamination. If analytical results
from a surface water sample exceed 2B Standards, then the area in the vicinity of the sample
location should be investigated for groundwater contamination.
12. Surface water/seep samples should be collected during basefl6w conditions and that the
groundwater monitoring (WLs and sampling) should occur at about the same time.
13. Measurement of streamflow in selected perennial streams is expected as needed in support of
simulation/calibration of flow and transport models; major rivers that serve as groundwater
divides are not included in this expectation.
Conceptual Model Elements
1. In the CSA report, data gaps remaining should be specifically identified and summarized.
2. Site heterogeneities should be identified and described with respect to: a) their nature, b)
their scale and density, c) the extent to which the data collection successfully characterizes
them, d) how the modeling accounts for them, e) and how they affect modeling uncertainty.

Attachment 1
Page 4 of 6
3. The impact of data gaps and site heterogeneities should be described in relation to the
elements developed in the Site Hydrogeologic Conceptual Model and Fate and Transport
Model subsections.
4. For sites in the Piedmont or Mountains, the CSA Report should include a subsection within the
Site Geology and Hydrogeology Section titled 'Structural Geology'. This section should
describe: a) foliations, b) shear zones, c) fracture trace analysis, and d) other structural
components anticipated to be relevant to flow and contaminant transport at the site.
5. Duke Energy will include a poster -sized sheet(s) (ANSI E) combining tabulated analytical
assessment results (groundwater, surface water, and leachate samples); multiple sheets may
be needed to present the data. This should be provided in addition to the individual analytical
results tables that will be prepared for the CSA reports. Any questions concerning format or
content of the analytical result summaries should be directed to the Regional offices.
Geochemical Modeling
I. The Division agrees that a geochemical model "coupled" to a 3-D fate and transport model is
inappropriate given the size and complexity of the sites and the extremely large amount of data
required to calibrate such a model. Rather, a "batch" geochemical model approach should be
sufficient for successfully completing the site assessment and/or corrective action plan.
2. Samples collected for "batch" geochemical analysis should be focused along or defensibly
proximate to flowpath transects.
3. To support successful batch geochemical modeling, dissolved groundwater samples collected
along a contaminant flowpath transect should be obtained using a 0.1 um filter. This will help
ensure a true dissolved phase sample. Note that the dissolved samples are for assessment
purposes only and may not be used for purposes of compliance monitoring. If there is
uncertainty about which areas/wells will be used in the batch geochemical modeling, the initial
round of assessment sampling at the facility can utilize the 0.45 um filter until the contaminant
flow path transects are selected. Once determined, Duke Energy can go back and re -sample the
wells needed for geochemical modeling using the 0.1 um filter. It is recognized that the use of a
0.1 um filter will be difficult for wells with elevated turbidity; in this case, it is recommended
that Duke Energy use two filters in series (the water initially passes through a 0.45 um filter to
remove larger particles prior to passing through the 0.1 um filter). Information for a disposable
0.1um field filter designed specifically for sampling groundwater for metal analysis is provided at
the following link: http://www.vosstech.com/index.php/products/fiIters. If field comparisons of
0.1 versus 0.45 micron filtration at several transect wells at a given site show no significant
differences between the two methods, then 0.45 micron filters may be used for evaluating the
dissolved phase concentrations at that site.
4. In support of the objectives of General Comment #2 of the November 4, 2014 GAP comments
issued by DWR , Duke Energy should add a column titled 'relative redox' to the analytical results
tables to record the geochemical conditions for that location/sample date. The redox
determination should be based on observed DO, ORP, and any other relevant measures and
presented for historic and new samples (wells, ash pore water, surface waters, etc.). Relative

Attachment 1
Page 5 of 6
redox designations may include "iron reducing", "sulfate reducing", mildly oxidizing, moderately
oxidizing, etc. and should be footnoted with a statement about the degree of confidence in the
designation based on amount and quality of available data.
5. Duke Energy shall also evaluate: a) spatial geochemical trends across the facility and along
selected flow paths, b) temporal geochemical trends where observable (such as for compliance
boundary wells), along with the likely reason for the change (e.g. increase in seasonal recharge,
pond de -watering and subsequent reversal of groundwater flow direction, inundation of well
from river at flood stage, etc.) in support of the CAP. This evaluation step will require a
comparison of geochemical conditions over time with rainfall data, notable ash capping,
dewatering, disposal/removal, or other plant operations, etc. The quality of existing
geochemical data will be evaluated using field notes, calibration records, and consistency in
redox measurements (e.g. eH vs. raw ORP).
Groundwater Models
1. The technical direction for developing the fate and transport modeling will follow guidelines
found in Groundwater Modeling Policy, NCDENR DWQ, May 31, 2007, and discussions
conducted between Duke Energy and their consultants with the Division. Ultimate direction for
completion of fate and transport models will be provided by the Division.
2. The CAP Report should include a subsection within Groundwater Modeling Results titled 'Site
Conceptual Model' that succinctly summarizes, for purposes of model construction, the
understanding of the physical and chemical setting of the site and shall include, at a
minimum: a) the site setting (hydrogeology, dominant flow zones, heterogeneities, areas of
pronounced vertical head gradients, areas of recharge and discharge, spatial distribution of
geochemical conditions across the site, and other factors as appropriate), b) source areas and
estimated mass loading history, c) receptors, d) chemical behavior of COPCs, and f) likely
retention mechanisms for COPCs and how the mechanisms are expected to respond to changes
in geochemical conditions.
3. Modeling will be included in the Corrective Action Plan (CAP). The four -tiered analysis
previously referenced and appropriate modeling should be conducted, and the mass flux
calculations described in the EPA/600/R-07/139 should be performed.
4. The CAP Report shall provide separate subsections for reporting groundwater flow models and
fate and transport models.
5. The CAP Report should include subsections within Groundwater Modeling Results titled
'Groundwater Model Development' that describes, for each chosen model: a) purpose of model,
built-in assumptions, model extent, grid, layers, boundary conditions, initial conditions, and
others as listed in Division guidance. Include in this section a discussion of heterogeneities and
how the model(s) account for this (e.g. dual porosity modeling, equivalent porous media
approach, etc.). Separate subsections should be developed for the groundwater flow model,
fate and transport model, and batch geochemical models, respectively.
6. CAP Reports should include a subsection within Groundwater Modeling Results titled
'Groundwater Model Calibration' that describes, for each model used, the process used to

Attachment 1
Page 6 of 6
calibrate the model, the zones of input and calibration variables (for example, hydraulic
conductivities) that were used, the actual (measured) versus modeled results for all key
variables, and others. Separate subsections should be developed for the groundwater flow
model, fate and transport model, and batch geochemical model(s), respectively.
7. CAP Reports should include a subsection within Groundwater Modeling Results titled
'Groundwater Model Sensitivity Analysis' that describes, for each model used, the process used
to evaluate model uncertainty, variable ranges tested, and the key sensitivities. Separate
subsections should be developed for the groundwater flow model, fate and transport model,
and batch geochemical model(s), respectively.
Development of Kd Terms
1. Kd testing and modeling in support of CAP development should include all COPCs found above
the NCAC ISA 02L .0106(8) standards in ash leachate, ash pore water, or compliance boundary
well groundwater samples.
2. The selected Kd used in transport modeling often will profoundly affect the results. Duke
Energy should acknowledge this concept and document within the transport modeling section(s)
of the CAP all widely recognized limitations inherent in the estimation of the Kd term.
Risk Assessment
1. Provide references for guidance and potential sampling methodology related to conducting a
baseline ecological risk assessment or habitat assessment, if warranted.

NCDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory Donald R. van der Vaart
Governor Secretary
June 9, 2015
CIERTIFIED MAIL 7002 0860 0006 5836 0342
RETURN RECEIPT REQUESTED
Mr. Harry Sideris
Senior Vice -President
Environment, Health and Safety
Duke Energy
526 South Church Street
Mail Code EC3XP
Charlotte, NC 28202
Subject: Notice of Regulatory Requirements
Title 15A North Carolina Administrative Code (NCAC) 02L.0106
L.V. Sutton Electric Plant
New Hanover County
Dear Mr. Sideris:
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.
On August 26, 2014, Duke Energy was issued a Notice of Violation and Notice of Intent to
Enforce for violations of Title 15A NCAC Subchapter 02L.0202 Groundwater Quality Standards
in monitoring wells located at or beyond the compliance boundary at the L.V. Sutton Electric
Plant in New Hanover County.
The violations of Groundwater Quality Standards for boron occurred in monitor wells MW -12,
MW -19, MW -21C, MW -22C, MW -2313, MW -23C, MW -24B, MW -24C, and MW -31C located
at or beyond the compliance boundary. Concentrations of boron were determined to be below
detection levels in background wells.
Recent sampling of water supply wells in the vicinity of the L.V. Sutton Electric Plant indicate
elevated levels of boron approaching the 2L Standard of 700 ug/1. Specifically, the well located
at 230 Sutton Lake Road had a boron concentration of 690 ug/1 and the well located at 235
Sutton Lake Road had a boron concentration of 600 ug/l. Although the complete site
assessment is still ongoing, indications are that these water supply wells are down -gradient of the
L.V. Sutton Electric Plant Ash Ponds.
1611 Mail Service Center, Raleigh, North Carolina 27699-1611
Phone: [phone] \ Internet: www.ncdenr.gov
An Equal Opportunity 1 Affirmative Action Employer — Made in part by recycled paper

Notice of Regulatory Requirements
L.V. Sutton Electric Plant
June 9, 2015
Title 15A NCAC 02L.0106(f) (2) states that corrective action required following discovery of the
unauthorized release of contaminant to the surface or subsurface of the land, and prior to or
concurrent with the assessment activities required in Paragraphs (c) and (d) of this rule, shall
include, but is not limited to "Abatement, containment, or control of the migration of
contaminants".
In order to ensure protection of existing water supply wells, we hereby direct Duke Energy to
take immediate action to control and prevent further migration of coal ash contaminants no later
than July 9, 2015, pursuant to 15A NCAC 02L .0106(f). The DWR requests that Duke Energy
provide the DWR with specific details concerning actions that Duke Energy plans to take to
comply with this rule. These details may include, but not be limited to:
(1) A description of the actions to be taken immediately by Duke Energy to abate,
contain or control the migration of contaminants towards nearby water supply
wells
(2) Specific plans, including engineering details and permits where applicable,
regarding these proposed actions
(3) A monitoring plan for evaluating the effectiveness of these actions
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 questions, please
feel free to contact me at [phone].
Sincerely,
S. Ja i erman, P.G.
Director. Division of Water Resources
cc: Jim Gregson, WQROS WiRO Supervisor
WQROS File Copy
WQ Permitting, Permit File NC0001422
New Hanover County Health Department
Page 2 of 2

NCDENR
Forth Carolina Department ut Environment and Natural Resources
Pat MUG[ uty
(3overnor
July 7, 2015
Duke Energy
c/o: Mr. D. Edwin M. Sullivat-I
P.O. Box 1006 Mail Code EC13K
Charlotte, North Carolina 28201-1006
RE: Conditional Approval Letter Response
L.V. Suttun Energy Complex
New Hanover County, North Carolina
Dear Mr. Sullivan:
Uonala R. van der Vaart
Seurtrtal y
The vivision of Water Resources received Duke Energy's May 22, 2U 15 response to DENR's
Conditional Approval dated February 6, 2015 for the L.V. Sutton Energy Coinplex Revised
Groundwater Assessment Work Plan. Duke Energy provided responses ter the following sections:
® 7.1 Subsurface Exploration
• 7.2 Ash Pure Waer and Groundwater Sampling and Analysis
a 7.3.1 Water Quality Sara les
Please incorporate and implement the agreed upon scvpe of work as related to the above conditions
and outlined in Duke Energy's May 22, 2015 response.
Additionally, Duke Energy requests guidance regadiiig solid phase testing methods for total
organic carbonate content. ResearLh conducted by the Division has not identified a laboratory
method for analysis of total orgaztic carbonate with respect to solid _phase samples. We appreciate
Duke Energy bringing this issue to ut.0 attention. Since a suitable laboratory method for tutal
urga.uic cai bursate has not been found, Duke Energy is not cumpclled to perfurm this analysis as part
of the groundwater assessment at the L.V. Sunun Plzuit and other facilities located in the Coastal
Plain.
Should you have any questions or require additional information, please contact Geoff Kegley at
910-796-7328.
Division -uT vvater RCsuarvCs - Water Quality Regional Operations Section - Wilmington Regional urm;e
1z1 Carainal Drive Ext., Wilmi,igton, NC 28405
Phone: [phone] \ Fax: 910-35U-z004t Internet: www.nt;denr.gov
An Equal Opportunity 1 AMrMdd,. Nedon tMplOya — Made In part by recycled paper

Mr. Sullivan
July 7, 2015
Page 2
Sll1l:GiGly,
i
MorGIIa S ezr 1"Ph.u, Y.E
Environm rogran Supervisor
Division of Water Resources Water duality Regional Operations
Wihnington Regional Office
cc: Ricky Miller — Duke Energy
John Toepfer — Duke Energy
Kathy Webb — Syn I erra Corporation
Steven Lmter — Div. Water Resources — CGntrul Office