NC0024406_Other_20160503

' DUKE
ENERGY.
April 28, 2016
Jeffrey O. Poupart
Water Quality Permitting Section Chief
Division of Water Resources
Department of Environmental Quality
State of North Carolina
1617 Mail Service Center
Raleigh, NC 27699-1617
Harry K. Sidens
Senior Vice President
Environmental, Health & Safety
526 S Church Street
Mail Code ECUP
Charlotte, NC 28202
[phone]
Subject: March 2, 2016 Insufficiency of Discharge Assessment Plans — Duke Energy Carolinas,
LLC and Duke Energy Progress, LLC
Dear Mr. Poupart:
This responds to your letter of March 2, 2016 to Duke Energy Carolinas, LLC and Duke Energy
Progress, LLC on March 2, 2016 regarding Duke Energy's proposed Discharge Assessment
Plans.
With regard to your letter describing changes in Section 3.2.2 Observation and Sampling:
• The discussion must include a statement noting that jurisdictional determinations regarding
the extent of waters of the United States and their relationship with identified seeps at the
subject facilities will be obtained from the United States Army Corps of Engineers (USA
COE).
Duke Energy does not yet have jurisdictional determinations from the US Army Corps of
Engineers for the relevant areas at all of the twelve sites mentioned in your letter. We submitted
applications for jurisdictional determinations in September, October, and November 2015 and
have since worked with the Corps of Engineers to schedule site visits and provide draft plats for
approval. Nonetheless, the timing of the approved jurisdictional determinations is up to the
Corps and outside of Duke's control. To date, out of these twelve sites, only Buck has an
approved jurisdictional determination, but we do not yet have the signed plats.
We will submit the maps you have requested for each site on a rolling basis, within a reasonable
period after the jurisdictional determinations are complete. In order to address the changes
described in your March 2, 2016 letter, we have added the following text at the start of Section
3.2.2.
Jurisdictional determinations regarding the extent of waters of the United States and
their relationship with identified seeps at the subject facilities will be obtained from the
United States Army Corps of Engineers (USA COE). Until jurisdictional determinations
are finalized by USA COE, preliminary information will be used to evaluate the seeps as
described in the section below.
RECEIVED/NCDE6l/DWR
MAY 0 3 2016
Water Quality
Permitting section

The second change in Section 3.2.2 described in your letter is as follows.
The schedule for water quality sampling of the seeps and related jurisdictional waters must
be more frequent than the semi-annual basis stated in the proposed DAPs. DWR
recommends a monthly monitoring schedule, consistent with the conditions described in the
DAPs' general assessment requirements, for all identified seeps that will continue for twelve
(12) months. After that time, monitoring may be reduced to a semi-annual basis until such
monitoring becomes a requirement of the NPDES permit.
We do not believe sampling monthly as part of a revised Discharge Assessment Plan is
warranted. For the larger receiving waters, data is available from sampling associated with
NPDES permits that demonstrates the lack of impact on the larger surface waters of the state.
In addition, we are conducting weekly observations of all AOWs on a dam or dike slope,
sampling any new seeps, and providing the analytical results to DEQ. We recommend the
sampling frequency under the DAPs remain at twice/year with the weekly inspections of dam
slopes for any new seeps with data provided to DEQ. We recommend that we collectively focus
our resources on the completion of all of the NPDES Wastewater Permits for the Duke Energy
sites and implement appropriate sampling frequency for each of the permitted seeps in that
document.
However, in order to address the changes described in your March 2, 2016 letter, we have
added the following text in Section 3.2.2.
In addition to sampling conducted with the semi-annual assessments, additional seep
sampling will be conducted at locations and at a frequency as determined through
discussions with NC DEQ personnel.
We would like to work with DEQ to achieve alignment of the various (present and future)
documents involving required seep activities including:
• Discharge Assessment Plans
• Discharge Identification Plans
• NPDES Wastewater Permits
_ • EPA requirements
• Any future legal agreements with either DEQ or EPA
Duke Energy is committed to providing the Department with additional information to facilitate
the issuance of new NPDES Wastewater permits. The issues are complex and require special
consideration, as illustrated by the time elapsed since the permit applications were submitted.
We look forward to working with you further to resolve the issues identified here on a mutually
acceptable schedule.
Sincerely,
Harry Sideris
Senior Vice President
Environmental, Health and Safety

Belews Creek Steam Station Ash Basin
Topographic Map and
Discharge Assessment Plan
NPDES Permit NCO024406
April 29, 2016
D

Duke Energy Carolinas, LLC I Discharge Assessment Plan �1J�
Belews Creek Steam Station Ash Basin
CONTENTS
Contents
Pa4e
Contents......................................................................................................................................i
Figuresand Tables.....................................................................................................................
ii
Section1 - Introduction..............................................................................................................
1
Section2 - Site Background.......................................................................................................
3
2.1 Plant Description..................................................................................................3
2.2 Ash Basin Description..........................................................................................3
2.3 Site Geologic/Soil Framework..............................................................................3
2.4 Topographic Map and Identification of Discharges
...............................................4
2.4.1 Engineered Drainage System for Earthen Dam........................................4
2.4.2 Non -Engineered Seep Identification.........................................................5
Section 3 - Discharge Assessment Plan.....................................................................................
6
3.1 Purpose of Assessment.......................................................................................6
3.2 Assessment Procedure........................................................................................6
3.2.1 General Assessment Requirements.........................................................6
3.2.2 Observation and Sampling.......................................................................7
3.2.3 Evaluation................................................................................................9
3.2.4 Assessment Reporting.............................................................................9
Section4 - References..............................................................................................................10

Duke Energy Carolinas, LLC I Discharge Assessment Plan �1
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FIGURES AND TABLES
Figures and Tables
Figure 1 — Site Location Map
Figure 2 — Topographic Map
Table 1 — Seep and Associated Discharge Locations and Descriptions
Table 2 — Laboratory Analytical Methods
Table 3 — Belews Creek Steam Station — Example of Surface Water/Seep Monitoring Flow and
Analysis Results Table

Duke Energy Carolinas, LLC I Discharge Assessment Plan �1�
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SECTION 1 - INTRODUCTION
Section 1 - Introduction
The purpose of this document is to address the requirements of North Carolina General Statute
(GS)130A-309.210(a) topographic map and (b) Assessment of Discharges from Coal
Combustion Residuals Surface Impoundments to the Surface Waters of the State, as modified
by North Carolina Senate Bill 729, for the Belews Creek Steam Station (BCSS) ash basin
operated under National Pollutant Discharge Elimination System (NPDES) Permit NC0024406.
The following requirements are contained in General Statute (GS) 130A-309.210(a):
(1) The owner of a coal combustion residuals surface impoundment shall identify all
discharges from the impoundment as provided in this subsection. The requirements for
identifying all discharges from an impoundment set out in this subsection are in addition
to any other requirements for identifying discharges applicable to the owners of coal
combustion residuals surface impoundments.
(2) No later than December 31, 2014, the owner of a coal combustion residuals surface
impoundment shall submit a topographic map that identifies the location of all (i)
outfalls from engineered channels designed or improved for the purpose of collecting
water from the toe of the impoundment and (ii) seeps and weeps discharging from the
impoundment that are not captured by engineered channels designed or improved for
the purpose of collecting water from the toe of the impoundment to the Department.
The topographic map shall comply with all of the following.
a. Be at a scale as required by the Department.
b. Specify the latitude and longitude of each toe drain outfall, seep, and weep.
c. Specify whether the discharge from each toe drain outfall, seep, and weep is
continuous or intermittent.
d. Provide an average flow measurement of the discharge from each toe drain outfall,
seep, and weep including a description of the method used to measure average flow.
e. Specify whether the discharge from each toe drain outfall, seep, and weep identified
reaches the surface waters of the State. If the discharge from a toe drain outfall,
seep, or weep reaches the surface waters of the State, the map shall specify the
latitude and longitude of where the discharge reaches the surface waters of the
State.
f. Include any other information related to the topographic map required by the
Department.
The following requirements are contained in General Statute (GS) 130A-309.210(b):
b) Assessment of Discharges from Coal Combustion Residuals Surface Impoundments to
the Surface Waters of the State. The owner of a coal combustion residuals surface
impoundment shall conduct an assessment of discharges from the coal combustion

Duke Energy Carolinas, LLC I Discharge Assessment Plan L1Wi
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SECTION 1 - INTRODUCTION
residuals surface impoundment to the surface waters of the State as provided in this
subsection. The requirements for assessment of discharges from the coal combustion
residuals surface impoundment to the surface waters of the State set out in this
f - subsection are in addition to any other requirements for the assessment of discharges
from coal combustion residuals surface impoundments to surface waters of the State
applicable to the owners of coal combustion residuals surface impoundments.
(1) No later than December 31, 2014, the owner of a coal combustion residuals surface
impoundment shall submit a proposed Discharge Assessment Plan to the
Department. The Discharge Assessment Plan shall include information sufficient to
allow the Department to determine whether any discharge, including a discharge
i - from a toe drain outfall, seep, or weep, has reached the surface waters of the State
and has caused a violation of surface water quality standards. The Discharge
Assessment Plan shall include, at a minimum, all of the following:
a. Upstream and downstream sampling locations within all channels that could
potentially carry a discharge.
b. A description of the surface water quality analyses that will be performed.
c. A sampling schedule, including frequency and duration of sampling activities.
d. Reporting requirements.
e. Any other information related to the identification of new discharges required by
the Department.
(2) The Department shall approve the Discharge Assessment Plan if it determines that
the Plan complies with the requirements of this subsection and will be sufficient to
protect public health, safety, and welfare; the environment, and natural resources.
(3) No later than 30 days from the approval of the Discharge Assessment Plan, the
owner shall begin implementation of the Plan in accordance with the Plan's
schedule.
The North Carolina Senate Bill 729 establishes the submittal date of this topographic map and
Discharge Assessment Plan no later than December 31, 2014.
The topographic map, developed to satisfy the requirements of GS1 30A-309.21 0(a), was
utilized as the basis for developing the assessment procedures presented in this plan, required
by GS130A-309.210(b).
2

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S SECTION 2 - SITE BACKGROUND
Section 2 - Site Background
2.1 Plant Description
BCSS is a coal-fired electricity -generating facility with a capacity of 2,240 megawatts located on
Belews Lake in Stokes County, North Carolina. BCSS is a two -unit station which began
commercial operation in 1974 (Figure 1). Belews Creek, a tributary of the Dan River, was
impounded by Duke Energy (formerly Duke Power at the time of initial impoundment) to form
Belews Lake. Belews Lake is approximately 3,800 acres in area and provides cooling water for
the station.
2.2 Ash Basin Description
The ash basin system consists of a single cell impounded by an earthen dike located on the
north end of the ash basin. The ash basin system was constructed from 1970-1972 and it is
- located approximately 3,200 feet northwest of the power plant. The waste boundary for the ash
basin encompasses approximately 342 acres.
The full pond elevation for the BCSS ash basin is approximately 750 feet. The normal pond
elevation of Belews Lake is approximately 725 feet.
Due to the nature of BCSS operations, inflows to the ash basin are highly variable. The inflows
from the station to the ash basin are discharged to the southeast portion of the ash basin. The
ash basin pond elevation is controlled by the use of concrete stoplogs. The discharge from the
ash basin is through a concrete discharge tower located in the northwest portion of the ash
basin. The concrete discharge tower drains through a 24-inch-diameter SDR 17 HDPE conduit
for approximately 1,600 feet and then discharges into a concrete flume box. The discharge is to
an un-named tributary that flows northward to the Dan River.
2.3 Site Geologic6Soii Framework
BCSS and its associated ash basin system are located in the Milton Belt of the Piedmont
physiographic province (Piedmont), one of several northeast -trending geologic belts of the
southern crystalline Appalachians. The rocks of the Milton belt were formed during the
Precambrian era and metamorphosed during the early to late Paleozoic era (Butler and Secor
1991). The Milton belt bedrock is characterized by strongly foliated gneiss and schist, commonly
with distinct compositional layering and having felsic composition —quartzite, calc-silicate
gneiss, and marble are minor units (Carpenter 1982).
The soils that overlie the bedrock in the area have generally formed from the in -place
weathering of the parent bedrock. The fractured bedrock is overlain by a mantle of
unconsolidated material known as regolith. The regolith, where present, includes the soil zone;
j a zone of weathered, decomposed bedrock known as saprolite; and alluvium. Saprolite, the
product of chemical and mechanical weathering of the underlying bedrock, is typically
composed of silt and coarser granular material up to boulder size and may reflect the texture of
the rock from which it was formed. The weathering products of felsic rocks may be sandy-
'._ _ textured and rich in quartz content while mafic rocks form a more clayey saprolite (LeGrand
2004).

Duke Energy Carolinas, LLC I Discharge Assessment Plan ���
Belews Creek Steam Station Ash Basin
SECTION 2 -SITE BACKGROUND
The BCSS ash basin is generally bounded to the north by the earthen dike and a natural ridge.
Pine Hall Road runs along the east and south sides of the ash basin and appears to generally
be located along a surface water divide. Belews Lake is located to the east and south of Pine
Hall Road. Middleton Loop road is located on the west side of the ash basin and appears to
generally be located along a surface water divide. The geology/groundwater conditions at the
site are expected to be generally consistent with the characteristics of the conceptual
groundwater model developed by LeGrand (LeGrand, 2004) for the Piedmont region.
- 2.4 Topographic Map and Identification of Discharges
A topographic map is presented in Figure 2 to meet the requirements of GS 130A-309.210(a) in
t'
the identification of outfalls from engineered channels as well as seeps and weeps.
Seepage is the movement of wastewater from the ash basin through the ash basin
embankment, the embankment foundation, the embankment abutments, basin rim, through
residual material in areas adjacent to the ash basin. A seep is defined in this document as an
expression of seepage at the ground surface. A weep is understood to have the same meaning
a,
as a seep.
Indicators of seepage include areas where water is observed on the ground surface and/or
where vegetation suggests the presence of seepage. Seepage can emerge anywhere on the
downstream face, beyond the toe, or on the downstream abutments at elevations below normal
pool. Seepage may vary in appearance from a "soft," wet area to a flowing "spring." Seepage
may show up first as only an area where the vegetation is lusher and darker green than
surrounding vegetation. Cattails, reeds, mosses, and other marsh vegetation often become
established in a seepage area (NCDENR, 2007). However, in many instances, indicators of
seeps do not necessarily indicate the presence of seeps. Areas of apparent iron staining and/or
excess iron bacteria may also indicate the presence of a seep.
Locations of seepage at the ground surface adjacent to the ash basin have been identified and
are shown in Figure 2. These areas include the earthen embankment which impound the ash
basin as well as adjacent areas where water from the ash basin may have infiltrated into the
underlying residual materials and expressed as seepage.
- 2.4.1 Engineered Drainage System for Earthen Dam
Earth dams are subject to seepage through the embankment, foundation, and abutments.
Seepage control is necessary to prevent excessive uplift pressures, instability of the
downstream slope, piping through the embankment and/or foundation, and erosion of material
- by migration into open joints in the foundation and abutments. The control of seepage is
performed by the use of engineered drains such as blanket drains, trench drains, and/or toe
drains. In certain cases, horizontal pipes may be installed into the embankment to collect and
control seepage. It is standard engineering practice to collect the seepage and convey seepage
away from the dam.
The Belews Creek ash basin dam (Stoke-116) was constructed with a drainage blanket, a
transverse filter drain, relief wells, and trench drains. Horizontal drains were installed after

Duke Energy Carolinas, LLC I Discharge Assessment Plan ���
Belews Creek Steam Station Ash Basin
SECTION 2 - SITE BACKGROUND
construction was completed. The drainage features, or outfalls, associated with the ash basin
dam are shown as required by GS 130A-309.210(a)(2)(i) on Figure 2.
2.4.2 Non -Engineered Seep Identification
Topographic maps of the site were reviewed to identify regions of the site where there was a
potential for ash -basin -related seepage to be present. These regions were determined by
comparing ash basin full pond elevations to adjacent topography with ground surface elevations
lower than the ash basin full pond elevation. HDR staff performed site observations within these
identified areas as part of NPDES inspections during the reapplication process during July and
August 2014 and documented locations where seepage was apparent at the time of the site
visit. These seeps are identified as required by GS 130A-309.210(a)(2)(ii) on Figure 2.
5

Duke Energy Carolinas, LLC I Discharge Assessment Plan 1 ��
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SECTION 3 - DISCHARGE ASSESSMENT PLAN
Section 3 - Discharge Assessment Plan
3.1 Purpose of Assessment
The purpose of the assessment is to determine whether existing, known discharges from toe
drain outfalls, seeps, and weeps associated with the coal combustion residuals surface
impoundment (ash basin) have reached the surface waters of the State and have caused a
violation of surface water quality standards as required by North Carolina General Statute 130A-
309.210(b).
Figure 2 and Table 1 present the background and downstream sampling locations to be
considered as part of this Discharge Assessment Plan (DAP). These locations may be
assessed by comparing surface water sampling analytical results of the associated background
location with the corresponding downstream location. For discharges located at the toe of a
dam, an upstream location within the channel may not have been possible to isolate for
comparison given the proximity to the ash basin, which would have the same chemical
composition as the discharge itself. As such, the upstream location was established upstream of
the ash basin and is considered "background." For discharges located a distance from the ash
basin, an identified upstream or "background" location for sampling may be compared to the
downstream portion of the discharge channel. The background and downstream sampling
locations are shown on Figure 2 with "B" and "D" identifiers, respectively, and the corresponding
seep locations associated with the sampling locations are indicated on Table 1.
3.2 Assessment Procedure
The assessment procedure associated with the Belews Creek ash basin is provided within this
section. In addition to the specific requirements for the assessment, Section 3.2 also provides
the general requirements, the frequency of assessment, documentation requirements, and a
description of the surface water quality analyses that will be performed.
3.2.1 General Assessment Requirements
Assessments are to be performed in three phases as follows:
Observation and Sampling (assessment site visit)
Evaluation
Assessment Reporting
The assessment site visit shall be performed when the background and downstream locations
are accessible and not influenced by weather events. Locations on or adjacent to the ash basin
embankments should be performed within two months after mowing, if possible. In addition, the
assessment site visit should not be performed if the following precipitation amounts have
occurred in the respective time period preceding the planned assessment site visit:
Precipitation of 0.1 inches or greater within 72 hours or
Precipitation of 0.5 inches or greater within 96 hours
The assessments shall be performed under the direction of a qualified Professional Engineer or
Professional Geologist on a semi-annual basis during the following months: April to May and

I
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Duke Energy Carolinas, LLC I Discharge Assessment Plan �1�
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SECTION 3 - DISCHARGE ASSESSMENT PLAN
I
October to November. The date of the initial assessment site visit shall be selected no later than
30 days from the approval of the Discharge Assessment Plan and should fall within one of the
semi-annual timeframes. Additional seep locations that may have been identified and
documented in an Identification of New Discharge report(s) shall be reviewed prior to performing
an assessment site visit, if available.
3.2.2 Observation and Sampling
Jurisdictional determinations regarding the extent of waters of the United States and their
relationship with identified seeps at the subject facilities will be obtained from the United States
Army Corps of Engineers (USACE). Until jurisdictional determinations are finalized by USACE,
preliminary information will be used to evaluate the seeps as described in the section below.
The initial assessment site visit should be performed to document baseline conditions of the
discharge channel, including location, extent (i.e., dimensions of affected area), and flow of
each discharge. Discharge channel background and downstream locations should be verified
using a Global Positioning System (GPS) device. Photographs should be taken from vantage
points that can be replicated during subsequent semi-annual assessments.
Initial and subsequent assessment site visits shall document a minimum of the following to
respond to the requirements in 130A-309.21 0.1 (b):
• Record the most recent ash basin water surface elevation and compare to the seep and
outfall and associated discharge location surface water elevations.
• For each discharge channel, the observer shall note the following as applicable on the
day of the assessment site visit:
o Is the discharge channel flowing at the time of the assessment site visit?
o Does the discharge channel visibly flow into a Water of the U.S. at the time of the
assessment site visit?
o How far away is the nearest Water of the U.S.?
o Document evidence that flow has or could reach a Water of the U.S. (e.g.,
( description of flow, including extent and/or direction) and describe the observed
condition. Evidence that flow could or has reached a Water of the U.S. may be
indicated by an inspection of the adjacent and downstream topographic drainage
features.
o Observe and document the condition of the discharge channel and outfall of the
engineered channel or seep location with photographs. Photographs are to be
taken from similar direction and scale as photographs taken during the initial
assessment site visit.
l;
• Record flow rate within the discharge channel, if measureable, using the following
methods:
7

Duke Energy Carolinas, LLC I Discharge Assessment Plan L:11
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SECTION 3 - DISCHARGE ASSESSMENT PLAN
t _
o Timed -volumetric method: Collect a volume of water from the discharge of the PVC
pipe directly into an appropriately sized container. Measure volumes (in mL) in the
field utilizing a graduated container. Record the amount of time (in seconds)
i'
needed to collect the volume of water and calculate the flows (in MGD) for the
;I
timed volume.
o A V-notch weir apparatus will be installed, if necessary, during the initial
assessment site visit to impound seepage at locations with a defined channel.
Once the impounded seep reaches equilibrium discharge, flows will be measured
using the timed -volumetric method described above.
l�
o Area -velocity method: Measure point velocities and water depth at a minimum of
20 stations along a transect setup perpendicular to the direction of flow using a
Swoffer® 3000 flow meter mounted to a standard United States Geologic Survey
(USGS) top -set wading rod. Utilize the average velocity and cross -sectional area of
the wetted channel to calculate flows in MGD.
• Collect water quality samples using the following methods:
o Collect background and downstream samples during a period with minimal
preceding rainfall to minimize potential effects of stormwater runoff. Sampling
procedures should prevent the entrainment of soils and sediment in water samples
that can result in analytical results not being representative of the flow. Because
Areas of Wetness (AOWs)/seeps often have poorly defined flow channels and
minimal channel depth, conventional grab samples collected directly into laboratory
containers or intermediate vessels is not possible without disturbance and
entrainment of soils and sediments. Further, many AOWs are contiguous with low-
lying areas subject to surface water runoff and resulting heavy sediment loading
during storm events or are near surface waters subject to flooding such that
representative samples of the AOW cannot be obtained. If the facility is unable to
obtain an AOW sample due to the dry, low flow or high flow conditions preventing
the facility from obtaining a representative sample, a "no flow" result or "excessive
flow" will be recorded.
o After collection, samples will be preserved and stored according to parameter -
specific methods and delivered to the laboratory under proper Chain -of -Custody
(COC) procedures.
o Analytical parameters for analysis include: F, As, Cd, Cu, Cr, Ni, Pb, Se, and Hg.
This list includes all parameters previously identified for seep sampling at Duke
Energy power plants for which relevant stream water quality standards are in place.
(This list is responsive to the statutory requirement for the discharge assessment to
allow determination whether discharges from toe drain outfalls, seeps, or weeps
have reached surface waters and caused a violation of surface water quality
standards.) Analyses shall be conducted by Duke Energy's Huntersville analytical
_ laboratory (NC Wastewater Certification #248) and Pace Analytical Laboratories

� I
Duke Energy Carolinas, LLC I Discharge Assessment Plan ���
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I
SECTION 3 - DISCHARGE ASSESSMENT PLAN
(NC Wastewater Certification # 12). Laboratory analytical methods used for each
constituent are provided in Table 2.
o Seep In -situ measurements: In -situ field parameters (temperature and pH) shall be
measured utilizing calibrated field meters either at the discharge of the seep
directly, at the discharge of the flow measurement devices, or in the water pool
created behind the device, if sufficient water depth did not exist at the device
discharge.
o Dan River and Ash Basin Sample Collection Method: Water quality samples and in -
situ measurements from the Dan River shall be collected at a location upstream
(Dan River -Upstream) and downstream (Dan River -Downstream) of the ash basin
(Figure 2). Additionally, water samples and in -situ measurements shall be collected
from an in -process ash basin location (Figure 2). The grab samples shall be
collected from the river and basin's surface (0.3 m) directly into appropriate sample
bottles.
• In addition to sampling conducted with the semi-annual assessments, additional seep
sampling will be conducted at locations and at a frequency as determined through
discussions with NC DEQ personnel.
3.2.3 Evaluation
Evaluation of the data from the initial assessment site visit will establish baseline conditions and
will serve as the basis for comparison for subsequent assessment site visit results. Evaluation of
observations and sampling results shall include location, extent (i.e., dimensions of affected
area), and flow of each discharge. The analytical results of the upstream and downstream
locations shall be compared to the 15A NCAC 2B standards for surface water quality upon
receipt to identify potential exceedances.
3.2.4 Assessment Reporting
Each assessment site visit shall be documented by the individual performing the assessment,
as described in Section 3.2.2 to meet the requirements in 130A-309.21 0.1 (b). The report should
contain site background, observation and sampling methodology, and a summary of the
observations and descriptions of the discharge channels observed, changes in observations
compared to previous assessment events, estimates of flows quantities, and photographs of
discharges and outfalls of engineered channels designed or improved for collecting water from
the impoundment. Photographs are to be numbered and captioned. The flow and analytical
results shall be recorded and presented in tables similar to the examples provided as Tables 1
and 3. The analytical results shall be compared to the 15A NCAC 2B standards for surface
water quality and exceedances highlighted. This information shall be compiled, reviewed, and
submitted to NC DEQ within 90 days from the Observation and Sampling event.

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Duke Energy Carolinas, LLC I Discharge Assessment Plan ���
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SECTION 4 - REFERENCES
Section 4 - References
Butler, J. R. and Secor, D. T. 1991. The Central Piedmont, p. 59-78, in Horton, J. W., Jr., and
Zullo, V. A., eds., The Geology of the Carolinas: The University of Tennessee Press,
Knoxville, Tennessee, 406p.
Carpenter, P. A., III. 1982. Geologic map of Region G, North Carolina: North Carolina
I
Department of Natural Resources and Community Development, Geological Survey
Section, Regional Geology Series 2, Scale 1:125,000.
LeGrand, Harry, Sr. 2004. A Master Conceptual Model for Hydrogeological Site
Characterization in the Piedmont and Mountain Region of North Carolina, North Carolina
Department of Environment and Natural Resources.
North Carolina Department of Environment and Natural Resources. 2007. Dam Operation,
Maintenance, and Inspection Manual, North Carolina Department of Environment and
Natural Resources, Division of Land Resources, Land Quality Division, 1985 (Revised
2007).
10

FIGURES
TABLES

3.000 0 3.000 6.000
F)2
SITE LOCATION MAP
BELEWS CREEK STEAM STATION
DUKE ENERGY CAROLINAS, LLC
STOKES COUNTY, NORTH CAROLINA
DATE
JULY 31, 2014
FIGURE 1

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36.296
-80.061
Continuous Twm&Voklmelnc
2-8
4-D
J
0.0011
B.I.- Lake
36.287
-80.063
5-7
36.287
-80.064
Continuous
Ted-Volumtri ec
kn
5-0
54
•V71
.
0.0057
Unknown Discharge Location
54
36.280
-80.079
Continuous
Tkned-Velumetnc
1-8
0.0017
P
Unknown Discharge
Location
SA
36.280
-80.072
Continuous
Tined-Vokimebic
r
0.0129
3.79
36.299
-00.076
Conlin-AreaVbelocity
2-8-
� 1
0.181
5.11
36.99
-00.076
Continuous
Area.Valocty
'
1
MD.
th-gh
36.297
-M0752
Continuous
Unkrwwn
H04
HD-5
through
HD-7, a
36.297
-80.075
No Flow
Unkngwt
HD-11A
}
HD-9
through
HM111
36,297
-00.075
No Flow
Unkrwvm
KOS
Through
36.297
-80.074
Continuous
Unk-
36.306
-80.080
HO-27
Tributary w the Dan
Rrv-
3-D
1 -B ' {
:gam
��-•
TF-1
1 36.297
1 -80.076
Contin-
0.03168
TF•2
36297
-00.076
cwinaaa
0.0744
1F-7
36.297
-80.071
CarTnuws
0.020736
Per"'
Flan•
36297
-80.075
Conan-
0.235152
_ 7
as - - C Q /
- v-`-
A
36.297
-80.074
No Flow
llnkrrown
B
36.297
4ML074
Cardin-
Unkrwwn
C
36.297
-80.074
No Fbw
Unknown
D,
36.297
-80.074
COMin-
Unknown
D2
38.297
-80.074
Conuou llna
Unknown
r.
-
m -8
�.'..•-
E
36.297
-80.075
No Flow
Unk-
D
36.297
40.076
Goniknious
Unkrwwn
H
36.297
-00.076
No Flow
Unknown
I
36.297
80.076
Conemnus
llrtknnwn
NOTES:
1. PARCEL DATA FOR THE SITE WAS OBTAINED FROM DUKE ENERGY REAL ESTATE AND IS APPROXIMATE.
2" ASH BASIN, ASH LANDFILL, AND STRUCTURAL FILL WASTE BOUNDARIES ARE APPROXIMATE. SCALE (FEET)
3. AS -BUILT MONITORING WELL LOCATIONS PROVIDED BY DUKE ENERGY.
4. ORTHOPHOTOGRAPHY WAS OBTAINED FROM NC ONEMAP GIS WEB SITE (DATED 2010). 600' 0 600' 1,200'
S. TOPOGRAPHIC CONTOURS WERE OBTAINED FROM NCDOT WEB SITE (DATED 2010) AND ARE APPROXIMATE. _ 4200'
6. THE ASH BASIN COMPLIANCE BOUNDARY IS ESTABLISHED ACCORDING TO THE DEFINITION FOUND IN 15A NCAC 02L.0107 (a).
7. HYDROGRAPHY WAS OBTAINED FROM THE USGS NATIONAL MAP VIEWER AND DOWNLOAD PLATFORM ON MARCH 28, 2014 (http://nationalmap"gov/viewer.htmi)
8. SEEP SAMPLING LOCATIONS ARE APPROXIMATE. SEEP AND HORIZONTAL DRAIN (HD) LOCATIONS IN INSET PROVIDED BY DUKE ENERGY.
9" NPDES OUTFALL AND WATER QUALITY SAMPLE LOCATIONS PROVIDED BY DUKE ENERGY.
10. SEE REPORT "BELEWS CREEK STEAM STATION ASH BASIN SURFACE WATER AND SEEP MONITORING - OCTOBER 2014, APPENDIX C" FOR DESCRIPTION OF DAM DRAINAGE SYSTEM
F)l
l9
f
NPDES 001
HD-5 - HD-7C FLUME
& HD-11A E @ TOE HD-1 -
TF-1 HD-4 TF
G B
H
~HD-9 - HD-16 -
HD-11 HD-27
INSET
I�
D1 & D2
LEGEND:
---
--
DUKE ENERGY PROPERTY BOUNDARY
ASH BASIN WASTE BOUNDARY
z,
ASH BASIN COMPLIANCE BOUNDARY
• •.
ASH BASIN COMPLIANCE BOUNDARY COINCIDENT
�/
•�
WITH DUKE PROPERTY BOUNDARY
STRUCTURAL FILL, ASH LANDFILL - EDGE OF WASTE
STREAM
TOPOGRAPHIC CONTOUR (4 FOOT)
ASH BASIN COMPLIANCE GROUNDWATER
MONITORING WELL
S-7
•
SEEP SAMPLE LOCATION (APPROXIMATE)
NPDES 001
A
NPDES OUTFALL LOCATION
ASH BASIN
tl
WATER QUALITY SAMPLE LOCATION
� 1{�
1-B
•
BACKGROUND SAMPLING LOCATIONS
1-D
0
DISCHARGE SAMPLING LOCATIONS
TOPOGRAPHIC MAP WITH IDENTIFIED
SEEPS AND OUTFALLS
DUKE ENERGY CAROLINAS, LLC
BELEWS CREEK STEAM STATION ASH BASIN
NPDES PERMIT #NC0024406
STOKES COUNTY, NORTH CAROLINA
DATE
DECEMBER 2014
FIGURE
2

Table 1— Belews Creek Steam Station Ash Basin — Seep and Associated Discharge Locations and Descriptions
Location
Discharge Location
Seep / Discharge
Coordinates
(NAD 83(
Flow
Flow Measurement
Discharge Location
'Coordinates
(NAD 83)
ID ""
Description
(MGD) and Method
Latitude
Longitude
Latitude
Longitude
36.302
-80.088
0.0053
Tributary to the Dan River
S4
36.293
-80.085
Continuous
Timed -Volumetric
1-D
0.0 063
S-2
36.297
-80.085
Continuous
Timed -Volumetric
0.0015
S3
36.298
-80.083
Continuous
Timed -Volumetric
Tributary to the Dan River
36.304
-80.081
2-D
0.0048
S-4
36.298
-80.082
Continuous
Timed -Volumetric
Volur
0.0059
S-5
36.300
-80.081
Continuous
Timed -Volumetric
36.296
-80.060
0.0034
Belews Lake
S3
36.296
-80.061
Continuous
Timed -Volumetric
4-D
0.0011
Belews Lake
36.287
-80.063
S-7
36.287
-80.064
Continuous
Timed -Volumetric
5-D
S-8
36.280
-80.078
Continuous
0.0057
Timed -Volumetric
Unknown Discharge Location
S-9
36.280
-80.072
Continuous
0.0017
Unknown Discharge Location
Timed -Volumetric

Location'
Discharge Location
See 1. Discharge.
p rg
Coordinates
t"noe3t
Flow
Flow Measurement
'Discharge Location
Coordinates
�NADB'�
ID
Description'
(MGD) and Method
Latitude
. Longitude
Latitude
Longitude
0.0129
S-10
36.299
-80.076
Continuous
city
Area -Velocity
0.1 81
S41
36.299
-80.076
Continuous
Area -Velocity
HD-1 through
36.297
-80.0752
Continuous
Unknown
HD-4
HD-5 through
36.297
-80.075
No Flow
Unknown
HD-7, & HD-11A
HD-9 through
36.297
-80.075
Continuous/
Unknown
HD-11
No Flow
Tributary to the Dan River
3-D
HD-16through
36.297
-80.074
Continuous
Unknown
HD-27
36.306
-80.080
TF-1
36.297
-80.076
Continuous
0.03168
TF-2
36.297
-80.076
Continuous
0.0144
TF-3
36.297
-80.074
Continuous
0.020736
Parshall Flume
36.297
-80.075
Continuous
0.235152
A
36.297
-80.074
No Flow
Unknown
B
36.297
80.074
Continuous
Unknown
C
36.297
-80.074
No Flow
Unknown

Seep / Discharge
ID
Location
Coordinates
1N�na
Flow
Description
Flow Measurement
(MGD) and Method
.. Discharge Location
Discharge Location
Coordinates
(MAD 83) '
Latitude
Longitude
Latitude
Longitude
D7
36.297
-80.074
Continuous
Unknown
D2
36.297
-80.074
Continuous
Unknown
E
36.297
-80.075
No Flow
Unknown
G
36.297
-80.076
Continuous
Unknown
H
36.297
•80.076
No Flow
Unknown
1
36.297
-80.076
Continuous
Unknown
Notes:
1. Flow description for each seep sample location is based on observation during site visits performed by HDR in June and July 2014
2. Flow measurements and analytical samples were collected on July 8, 15, and 16, 2014
3. Location coordinates for seep sampling locations are approximate

Table 2 — Laboratory Analytical Methods
Parameter
Method
Reporting, ,
Units
Laboratory
-
Fluoride (F)
EPA 300.0
1
mg/I
Duke Energy
Mercury (Hg)
EPA 245.1
0.05
Ng/I
Duke Energy
Arsenic (As)
EPA 200.8
1
Ng/I
Duke Energy
Cadmium (Cd)
EPA 200.8
1
Ng/I
Duke Energy
Chromium (Cr)
EPA 200.8
1
Ng/I
Duke Energy
Copper (Cu)
EPA 200.8
1
Ng/I
Duke Energy
Lead (Pb)
EPA 200.8
1
Ng/I
Duke Energy
Nickel (Ni)
EPA 200.8
1
Ng/I
Duke Energy
Selenium (Se)
EPA 200.8
1
Ng/I
Duke Energy

Table 3 - Belews Creek Steam Station - Example of Surface Water/Seep Monitoring Flow and Analysis Results Table
:
-
Dan,
Dan•
Parameter
Units
S4'
S-2
.S-3
S-d
S=5 .'
" 'S-6
S-7
S-8
S-9
S-10
S-11
River=
River=D/S
U/S
Fluoride
mg/l
<
1
<
1
<
1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
<
1
Hg - Mercury
(71900)
N9
<
0.05
<
0.05
<
0.05
< 0.05
< 0.05
< 0.05
< 0.05
< 0.05
< 0.05
0.09
0.0
< 5
< 0.05
<
0.05
As - Arsenic
(01002)
Ng/1
<
1
<
1
1.39
< 1
< 1
1.57
10.6
< 1
< 1
1.81
2.1
4
< 1
<
1
Cd - Cadmium
N9�
1
< 1
< 1
< 1
< 1
1
< 1
< 1
<
1
(01027)
<
1
<
1
<
1
< 1
<
Cr- Chromium
Ngn
1
< 1
< 1
< 1
< 1
< 1
< 1
<
1
(01034)
<
1
<
1
<
1
< 1
< 1
<
Cu- Copper
(01042)
N9/1
2.63
<
1
1.42
< 1
< 1
< 1
13.9
2.62
3.58
< 1
< 1
< 1
<
1
Pb - Lead
(01051)
Ng/I
<
1
<
1
<
1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
< 1
<
1
Ni- Nickel
(01067)
N911
<
1
1.03
<
1
1.04
< 1
1.17
< 1
< 1
9.79
11.4
11.
1
< 1
<
1
Se - Selenium
Ng �
< 1
< 1
3.58
7
< 1
< 1
< 1
<
1
(01147)
<
1
<
1
<
1
< 1
< 1
5.9
pH
S.U.
5.5
5.9
6.77
5.7
6.32
6.55
6.09
5.5
6.41
5.73
2
7.12
6.47
22.
Temperature
°C
20.4
22.1
20.2
20.3
22.2
22.7
24.4
20.8
25.4
20.2
3
31.6
29.7
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.01
0.1
158.
Flow
MGD
53
63
15
48
59
34
11
57
17
29
81
3
158.3
Notes:
1. Flow measurements and analytical samples were collected on July 8, 15, and 16, 2014
2. S-7 sample temperature upon receipt in the analytical lab was slightly above 6 degrees Celsius (7.9 degrees C)
3. Flow at locations upstream and downstream of BCSS in the Dan River is from the USGS Dan River -Pine Hall daily average flows for the date of river sampling