NC0005088_2014 Discharge Assmt Plan_20141230

Cliffside Steam Station Ash Basin
Topographic Map and
Discharge Assessment Plan
NPDES Permit NC0005088

December 30, 2014

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Cliffside Steam Station Ash Basin
CONTENTS

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Contents
Page
Contents ...................................................................................................................................... i
Figures and Tables ..................................................................................................................... ii
Section 1 - Introduction .............................................................................................................. 1
Section 2 - Site Background ....................................................................................................... 3
2.1 Plant Description .................................................................................................. 3
2.2 Ash Basin Description .......................................................................................... 3
2.3 Site Geologic/Soil Framework .............................................................................. 4
2.4 Topographic Map and Identification of Discharges ............................................... 5
2.4.1 Engineered Drainage System for Earthen Dam ........................................ 5
2.4.2 Non-Engineered Seep Identification ......................................................... 6
Section 3 - Discharge Assessment Plan..................................................................................... 7
3.1 Purpose of Assessment ....................................................................................... 7
3.2 Assessment Procedure ........................................................................................ 7
3.2.1 General Assessment Requirements ......................................................... 7
3.2.2 Observation and Sampling ....................................................................... 8
3.2.3 Evaluation…… ....................................................................................... 10
3.2.4 Assessment Reporting ........................................................................... 10
Section 4 - References ..............................................................................................................11

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Cliffside Steam Station Ash Basin
FIGURES AND TABLES

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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 – Cliffside Steam Station – Example of Surface Water/Seep Monitoring Flow and
Analysis Results Table

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Cliffside Steam Station Ash Basin
SECTION 1 - INTRODUCTION

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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 Cliffside Steam Station (CSS) ash basin operated
under National Pollutant Discharge Elimination System (NPDES) Permit NC0005088.
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
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SECTION 1 - INTRODUCTION

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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
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
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 GS130A-309.210(a), was
utilized as the basis for developing the assessment procedures presented in this plan, required
by GS130A-309.210(b).
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SECTION 2 - SITE BACKGROUND

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Section 2 - Site Background
2.1 Plant Description
CSS is a coal-fired, electricity-generating facility located along the south bank of the Broad River
in Rutherford and Cleveland Counties at 573 Duke Power Road, Cliffside, North Carolina
(Figure 1). CSS currently operates Units 5 and 6 only. The original Units 1–4 were retired in
October 2011. The surrounding area generally consists of residential properties, undeveloped
land, and the Broad River.
2.2 Ash Basin Description
The station has one active ash basin and two inactive ash basins, the Units 1–4 inactive ash
basin, and the Unit 5 inactive ash basin as shown on Figure 1. The active ash basin and the
Units 1–4 inactive ash basin are located in Cleveland County to the east and southeast of the
CSS. The Unit 5 inactive ash basin is located in Rutherford County west of the CSS.
The active ash basin is located approximately 1,700 feet to the east-southeast of CSS adjacent
to the Broad River as shown on Figure 2. The active ash basin is impounded by earthen dikes
located between the west portion of the basin and Suck Creek and between the northeast
portion of the basin and the Broad River. The waste boundary associated with the active ash
basin is approximately 117 acres in area. The approximate maximum pond elevation of the
active ash basin is 770 feet. The main section of the pond is operated below 765 feet to have
extra storage capacity during a heavy flood event.
The two ash storage areas are located adjacent to the active ash basin. The ash located in
these storage areas was removed from the active ash basin. The Units 1–4 inactive ash basin is
located approximately 400 feet to the southeast of the retired Units 1–4 and approximately
1,300 feet to the northeast of Unit 6, adjacent to the Broad River (Figure 2). The Units 1–4
inactive ash basin is impounded by an earthen dike located along the north and northeast side
of the basin. The waste boundary associated with the Units 1–4 inactive ash basin is
approximately 14.5 acres in area.
The Unit 5 inactive ash basin is located approximately 1,000 feet to the southwest of Unit 5 and
approximately 1,000 feet west of Unit 6, south of the Broad River (Figure 2). The Unit 5 inactive
ash basin is impounded by two earthen dikes located along the north and northeast sides of the
basin. The waste boundary associated with the Unit 5 inactive ash basin is approximately 58
acres in area. The ash basin system has been an integral part of the station’s wastewater
treatment system which has received inflows from the ash removal system, station yard drain
sump, stormwater flows, and station wastewater. Currently, the inflows from the ash removal
system and the station yard drainage basin are discharged through High Density Polyethylene
Pipe (HDPE) sluice lines into the active ash basin. The inflows are variable based on Unit 5 and
Unit 6 operations.
Effluent from the ash basin system is discharged from the active basin to the Broad River
through a concrete discharge tower located in the northeast portion of the basin. The concrete
discharge tower drains through a 42-inch reinforced concrete pipe (RCP) into a riprap-lined
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SECTION 2 - SITE BACKGROUND

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channel that discharges to the Broad River. The ash basin pond elevation is controlled by the
use of concrete stoplogs.
2.3 Site Geologic/Soil Framework
CSS is located within the Piedmont zone, one of several northeast-trending geologic belts of the
southern crystalline Appalachians. The zone lies between the Charlotte Terrane of the Carolina
zone to the east and the Blue Ridge Terrane to the west. Rocks in the Piedmont zone have
undergone intense metamorphism, folding, faulting, and igneous intrusion.
The Piedmont zone is a fault-bounded composite stack of thrust sheets containing a variety of
gneisses, schists, amphibolites, sparse ultramafic bodies, and intrusive granitoids (Horton and
McConnell, 1991; Nelson and others, 1998). The general structure within the zone is
characterized by irregular foliation of low dip and folds transverse to the northeast regional
trend. The stratified rocks consist of thinly layered mica schist and biotite gneiss that are
interlayered with lesser amounts of amphibolite, calc-silicate rocks, hornblende gneiss, and
quartzite. Protoliths of these rocks were largely sedimentary and in part volcanic. Large and
small masses of granite and granodiorite are present throughout the belt and form concordant to
semi-concordant bodies in the country rock. Some of these granitoid bodies are gneissic and
are probably older than the poorly foliated to non-foliated facies. Small, ultramafic masses are
present along the eastern and western edges of the belt. The rocks of the central core of the
Western Piedmont zone are in the sillimanite zone of amphibolite metamorphism with the flanks
primarily in the staurolite-kyanite zone (Butler, 1991).
In the Piedmont zone, a variable thickness and degree of soil, saprolite, and weathered rock,
referred to as regolith, typically overlie crystalline bedrock. The degree of weathering typically
decreases with depth with a thoroughly weathered and structureless material at the surface
termed residuum. The residuum grades into a relatively coarse-grained material that retains the
structure of the parent bedrock and is termed saprolite (can extend to greater than 150 feet in
depth below the ground surface). Beneath the saprolite, partially weathered bedrock occurs with
depth until sound bedrock is encountered.
A transition zone may occur at the base of the regolith between the soil-saprolite and the
unweathered bedrock. This transition zone of partially weathered rock is a zone of relatively
high permeability compared to the overlying soil-saprolite and the underlying bedrock (LeGrand
2004).
Groundwater flow paths in the Piedmont are almost invariably restricted to the zone underlying
the topographic slope extending from a topographic divide to an adjacent stream. LeGrand
describes this as the local slope aquifer system. Under natural conditions, the general direction
of groundwater flow can be approximated from the surface topography (LeGrand 2004).
Groundwater recharge in the Piedmont is derived entirely from infiltration of local precipitation.
Groundwater recharge occurs in areas of higher topography (i.e., hilltops) and groundwater
discharge occurs in lowland areas bordering surface water bodies, marshes, and floodplains
(LeGrand 2004).
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SECTION 2 - SITE BACKGROUND

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The CSS site is located on the southern bank of the Broad River and lies in both Cleveland and
Rutherford Counties. McCraw Road runs from northwest to southeast in the vicinity of the site
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 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
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
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. 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 embankments 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 Cliffside active ash basin downstream dam and upstream dam were constructed with a
zoned trench drain, a zoned blanket drain, and a zoned toe drain. The engineered drainage
system features, or outfalls, associated with the ash basin dam are shown as required by GS
130A-309.210(a)(2)(i) on Figure 2.
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SECTION 2 - SITE BACKGROUND

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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 June,
July, September, and November 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.

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SECTION 3 - DISCHARGE ASSESSMENT PLAN

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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 Cliffside 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 within two nonadjacent quarters. The date of the
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SECTION 3 - DISCHARGE ASSESSMENT PLAN

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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
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-309.210.1(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 W ater 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.
• Record flow rate within the discharge channel, if measureable, using the following
methods:
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)
needed to collect the volume of water and calculate the flows (in MGD) for the
timed volume.
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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.
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. Collect
samples from the discharge channel at the flow measurement devices or directly
from the discharge into sample bottles while minimizing disturbance and
entrainment of soil/sediment. 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: Fluoride, Arsenic, Cadmium, Copper,
Chromium, Nickel, Lead, Selenium, and Mercury. 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 (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 Broad River and Ash Basin Sample Collection Method: Water quality samples and
in-situ measurements from the Broad River shall be collected at a location
upstream and downstream of the ash basin. Additionally, water samples and in-situ
measurements shall be collected from an in-process ash basin location. The grab
samples shall be collected from the river and basin’s surface (0.3 m) directly into
appropriate sample bottles.
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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-309.210.1(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 NCDENR within 90 days from the Observation and Sampling event.

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SECTION 4 - REFERENCES

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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.
Horton, J. W., Jr. and McConnell, K. I. 1991. The western Piedmont, p. 36-58, in Horton, J. W.,
Jr. and Zullo, V. A., eds., The Geology of the Carolinas: The University of Tennessee
Press, Knoxville, TN, 406p.
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).

FIGURES
AND
TABLES

Table 1 – Cliffside Steam Station Ash Basin – Seep and Associated Discharge Locations and Descriptions Seep / Discharge ID Location Coordinates (NAD 83) Flow Description Flow Measurement (MGD) and Method Background Location Discharge Location and Discharge Sampling Location Discharge Location Coordinates (NAD 83) Latitude Longitude Latitude Longitude S-1 35.216 -81.775 Continuous 0.0646 area-velocity 1-B Northwest of the Inactive Unit 5 ash basin; tributary of Broad River 1-D 35.218 81.775 S-2 35.217 -81.768 Continuous 0.2004 area-velocity Downriver from Inactive Unit 5 ash basin discharge canal 2-D 35.218 81.767 S-3 35.220 -81.758 Continuous 0.0582 area-velocity At discharge canal for Units 1-4; tributary of Broad River 3-D 35.218 -81.753 S-4 35.218 -81.753 Continuous 0.0129 area-velocity North of the ash storage area; below outfall of concrete ditch 4-D 35.219 -81.746 S-5 35.218 -81.750 Continuous 0.0014 timed-volumetric North of the ash storage area; below outfall of concrete ditch 4-D S-6 35.218 -81.748 Continuous 0.0323 area-velocity Downgradient of the active ash basin dike; tributary of Broad River 4-D S-7 35.218 -81.746 Continuous 0.0078 timed-volumetric Northeast of the active ash basin; northeast corner of property 4-D S-8 35.208 -81.756 Continuous <0.0129 timed-volumetric Tributary to Suck Creek 3-D 35.218 -81.753 S-9 35.217 -81.754 Continuous 0.0013 timed-volumetric East side of Suck Creek; downstream of bridge 3-D S-10 35.220 -81.757 Continuous 0.0004 timed-volumetric Below inactive Units 1-4 south bank of Broad River 3-D S-11 35.219 -81.756 Continuous 0.0025 timed-volumetric Below inactive Units 1-4 south bank of Broad River 3-D S-12 35.217 -81.752 Continuous 0.0003 timed-volumetric Below ash storage basin; south bank of Broad River 4-D 35.219 -81.746 S-13 35.218 -81.75 No Flow N/A Along Units 1-4 dike 3-D 35.218 -81.753 S-14 35.214 -81.756 No Flow N/A Along active ash basin dike 3-D S-15 35.214 -81.756 No Flow N/A Along active ash basin dike 3-D
Seep / Discharge ID Location Coordinates (NAD 83) Flow Description Flow Measurement (MGD) and Method Background Location Discharge Location and Discharge Sampling Location Discharge Location Coordinates (NAD 83) Latitude Longitude Latitude Longitude S-16 35.214 -81.756 No Flow N/A Along active ash basin dike 3-D S-17 35.217 -81.769 Continuous 0.0017 timed-volumetric Along active ash basin dike; seepage from Unit 5 2-D 35.218 -81.767 S-18 35.216 -81.768 Continuous 0.0046 timed-volumetric Seepage from riprap at toe of Unit 5 2-D S-19 35.216 -81.768 Continuous 0.0009 timed-volumetric Seepage from wooded area at toe of Unit 5 2-D S19a 35.216 -81.769 Continuous 0.0005 timed-volumetric Seepage from wooded area at toe of Unit 5 2-D S-20 35.215 -81.765 No Flow N/A Seepage at toe of Unit 5 2-D S-21 CLEVE-050 35.214 -81.755 No Flow Engineered drainage at Suck Creek dam at active ash basin 3-D 35.218 -81.753 S-22 CLEVE-049 35.217 -81.749 Continuous Engineered drainage downstream dam at active ash basin 3-D 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 7, 9, and 22, 2014; and November 10, 2014 3. Location coordinates for seep sampling locations are approximate 4. Location coordinates (degrees) in NAD 83 datum

Table 2 – Laboratory Analytical Methods
Parameter Method Reporting
Limit Units Laboratory
Fluoride (F) EPA 300.0 1 mg/l Duke Energy
Mercury (Hg) EPA 245.1 0.05 µg/l Duke Energy
Arsenic (As) EPA 200.8 1 µg/l Duke Energy
Cadmium (Cd) EPA 200.8 1 µg/l Duke Energy
Chromium (Cr) EPA 200.8 1 µg/l Duke Energy
Copper (Cu) EPA 200.8 1 µg/l Duke Energy
Lead (Pb) EPA 200.8 1 µg/l Duke Energy
Nickel (Ni) EPA 200.8 1 µg/l Duke Energy
Selenium (Se) EPA 200.8 1 µg/l Duke Energy
Table 3 – Cliffside Steam Station – Example of Surface Water/Seep Monitoring Flow and Analysis Results Table Parameters Units S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 S-12 S-17 Fluoride mg/l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 Hg ‐‐‐‐ Mercury (71900) µg/l < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 As ‐‐‐‐ Arsenic (01002) µg/l < 1 < 1 5.51 28.6 < 1 < 1 < 1 < 1 < 1 334 104 < 1 < 1 Cd ‐‐‐‐ Cadmium (01027) µg/l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 Cr ‐‐‐‐ Chromium (01034) µg/l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 Cu ‐‐‐‐ Copper (01042) µg/l < 1 < 1 1.24 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 Pb ‐‐‐‐ Lead (01051) µg/l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 Ni ‐‐‐‐ Nickel (01067) µg/l < 1 9.01 59.3 < 1 < 1 1.82 < 1 < 1 1.45 < 1 10.4 < 1 < 1 Se ‐‐‐‐ Selenium (01147) µg/l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 1 1.64 pH s.u. 6.7 7 5.8 7 5.6 6.5 6.2 6.4 5.9 6.7 6.6 6.5 5.15 Temperature °F 68.2 74 75.5 64.9 61.3 62.3 67.7 66.0 62.4 74.4 73.6 15.8 16.7 Flow MGD 0.0646 0.2004 0.0582 0.0129 0.0014 0.0323 0.0078 < 0.0129 0.0013 0.0004 0.0025 0.0003 0.0017 Parameters Units S-18 S-19 S-19a Ash Basin in Process Broad River Upstream Broad River Downstream Fluoride mg/l < 1 < 1 < 0.1 < 1 < 1 < 1 Hg ‐‐‐‐ Mercury (71900) µg/l < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 < 0.05 As ‐‐‐‐ Arsenic (01002) µg/l < 1 < 1 < 1 < 51.9 < 1 < 1 Cd ‐‐‐‐ Cadmium (01027) µg/l < 1 < 1 < 1 < 1 < 1 < 1 Cr ‐‐‐‐ Chromium (01034) µg/l < 1 < 1 < 1 < 15 < 1 < 1 Cu ‐‐‐‐ Copper (01042) µg/l < 1 < 1 < 1 < 1.6 < 1 < 1 Pb ‐‐‐‐ Lead (01051) µg/l < 1 < 1 < 1 < 1 < 1 < 1 Ni ‐‐‐‐ Nickel (01067) µg/l 24.3 < 1 8.94 1.24 < 1 < 1 Se ‐‐‐‐ Selenium (01147) µg/l < 1 < 1 < 1 < 32.5 < 1 < 1 pH s.u. 6.3 6.4 6.8 10 7.3 7.9 Temperature °F 17.7 13.3 15.8 87.1 79 79.7 Flow MGD 0.0046 0.0009 0.0005 537 < 537 Notes: 1. Flow measurements and analytical samples for were collected on July 7, 9, and 22, 2014; October 22, 2014; November 10, 2014 2. Flow at locations upstream and downstream of CSS in the Broad River is from the USGS Broad River-Boiling Springs daily average flows for the date of river sampling