Duke Roxboro Additional Wells Tech Memo R1_20190215

Date:
To:
Cc:
From:
Subject:
February 15, 2019
Kimberlee Witt (Duke Energy)
Craig Eady (SynTerra)
Kyle Lawing (SynTerra)
TECHNICAL MEMORANDUM
File: 1026.107
Additional Groundwater Monitoring Wells - Roxboro Steam Electric Plant
West Ash Basin (WAB) Southern Extension Impoundment (SEI) - Additional
Wells REVISED
Duke Energy Progress, LLC (Duke Energy) owns and operates the Roxboro Steam
Electric Plant (Roxboro or Site) in Semora, Person County, North Carolina. Additional
groundwater assessment activities proposed for the area south of the West Ash Basin
(WAB) Southern Extension Impoundment (SEI) are described herein.
Regulatory Background
In 2014, The North Carolina General Assembly passed the Coal Ash Management Act
(CAMA). CAMA required owners of a coal combustion residuals (CCR) surface
impoundment to conduct detailed assessment of site groundwater and soil within and
around the CCR surface impoundments.
A primary source of CCR-related constituents was identified during the
Comprehensive Site Assessment (CSA) for CAMA to be related to the two ash basins,
the East Ash Basin (EAB) and the West Ash Basin (WAB). In response to the October
2017 CSA Update, the North Carolina Department of Environmental Quality (NCDEQ)
requested additional evaluation of groundwater to the south of the WAB SEI to
determine the presence, absence, and/or degree of possible impact from historical coal
combustion waste management at Roxboro.
Site Description
Roxboro is a coal-fired steam station owned and operated by Duke Energy that
generates electrical power for thousands of customers in North Carolina. The Site is
situated on approximately 6,095 acres of company owned property located between
McGhees Mill Road to the east, Semora Road (Highway 57) to the south and Hyco
Reservoir to the west and north (Figure 1). Roxboro began operations in the 1960s and
continued to add capacity through the 1980s. Currently, the Plant operates four coal-
fired units. CCR materials, composed primarily of fly ash and bottom ash, were
historically managed by depositing ash within two basins (surface impoundments)
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West Ash Basin (WAB) Southern Extension Impoundment (SEI) - Additional Wells February 15, 2019
Roxboro Steam Electric Plant Page 2 of 4
located on the Site and referenced using relative location: the EAB and WAB, with
construction of each basin beginning in approximately 1966 and 1973, respectively.
CCRs were deposited in the basins predominately by hydraulic sluicing operations
until the plant was modified for dry fly ash handling operations and the on -site
industrial landfill placed in service in the 1980s. Most of the fly ash material produced
at the facility is currently collected by dry handling operations and are disposed within
the industrial landfill located mostly within the EAB footprint or transported offsite for
beneficial reuse. Bottom ash continues to be deposited within the WAB area by
hydraulic sluicing methods with expectations for complete dry handling of CCRs in
2019. Groundwater monitoring associated with the Plant's National Pollution
Discharge Elimination System (NPDES) permit has been conducted since 2010.
WAB Southern Extension Impoundment - Additional Wells
Objectives of the WAB SEI additional monitoring well installation include the
following:
• Assess soil and groundwater conditions in the vicinity of the two southern
"lobes" of the WAB Southern Extension Impoundment, where monitoring
wells have not been installed previously
• Compare inorganic constituent concentrations in shallow unsaturated soil
associated with two monitoring well clusters south of the WAB SEI area to
Site background concentrations
• Compare inorganic constituent concentrations in groundwater associated
with two monitoring well clusters south of the WAB SEI area to Site
background concentrations
Soil Sampling
Soils associated with the monitoring well clusters will be sampled and analyzed for
inorganic parameters to determine the presence, absence, and/or degree of possible
impact from the CCR materials. Soil samples are planned to be collected from
unsaturated, saprolitic soils during the installation of one monitoring well associated
with each proposed well cluster. Proposed locations (Figure 2) are approximate and
may vary based on field observations and locations of underground utilities, which will
be determined prior to initiation of drilling activities.
Soil samples will be analyzed for inorganic parameters consistent with assessment of
areas used for CCR management (Table 1). Soil samples will be collected from below
the near ground surface (two to three feet) and at approximately two to five foot
intervals to the top of the groundwater table or bedrock, whichever is encountered first.
Soil samples submitted for laboratory analysis will be "grab" samples and will not be
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West Ash Basin (WAB) Southern Extension Impoundment (SEI) - Additional Wells February 15, 2019
Roxboro Steam Electric Plant
Page 3 of 4
composited. Collected soil will be placed directly into new bottleware provided by the
NC certified analytical laboratory.
Monitoring Well Installation
Two monitoring well clusters (three wells per cluster), MW-38 and MW-39, are
proposed in the vicinity of the two southern "lobes" of the WAB SEI, as shown on
Figure 2. At the issuance of this Technical Memorandum, an access route has not been
established to the proposed MW-38 monitoring well cluster location. Once an
appropriate access route has been established, Duke Energy will seek approval from the
NCDEQ Raleigh Regional Office (RRO) with a more accurate and field verified
monitoring well cluster location. The approximate route accessing the proposed MW-
39 monitoring well cluster location is depicted on Figure 2. The proposed monitoring
wells will be installed following appropriate access and permit approvals including
NCDEQ Erosion & Sediment Control (E&SC).
The proposed monitoring wells will be screened in the surficial (S), transition (D), and
upper bedrock (BR) flow zones (as saturated conditions are observed) to assess
groundwater quality and evaluate horizontal and vertical migration of constituents.
Estimated depths from ground surface for each zone are 40 feet below ground surface
(bgs) for the surficial well, 80 feet bgs for the transition zone well, and 130 feet bgs for
the upper bedrock well as shown on Table 2.
It is proposed the boreholes will be drilled utilizing one or a combination of the
following: hollow -stem augers, air rotary (specifically, pneumatic air hammer), rock
coring, and/or rotary sonic drilling techniques. Well installation procedures and well
construction materials and lengths will be consistent with ongoing CAMA assessment
activities in accordance with the approved Proposed Groundwater Assessment Work Plan
(Rev. 1) (SynTerra, 2014) and in accordance with NCAC Title 15A, Subchapter 2C,
Section .0100 Well Construction Standards. Shallow wells are proposed to be installed
so that the top of the screened interval is positioned approximately five feet below the
water table, where practical, to avoid potential biofouling and introduction of artificial
geochemical conditions, which are common among monitoring wells with screened
intervals that bracket the water table.
Groundwater Sampling
Following monitoring well installation and development, groundwater samples will be
collected from each newly installed well using low flow sampling techniques utilizing
either a peristaltic pump or dedicated submersible pump to minimize sampling error,
reduce entrainment of suspended sediments and prevent cross contamination of
samples. Groundwater samples will be analyzed for field parameters (e.g., pH, specific
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West Ash Basin (WAB) Southern Extension Impoundment (SEI) — Additional Wells February 15, 2019
Roxboro Steam Electric Plant
Page 4 of 4
conductivity, Eh (ORP), DO, and turbidity) and inorganic constituents consistent with
ongoing CAMA assessment activities (Table 3).
Reporting
This information is being gathered to address "data gap" areas as requested by NCDEQ
following the review of the Roxboro October 2017 CSA Update, and determined
necessary for the forthcoming Corrective Action Plan (CAP) Update document. The
results will contribute to the overall understanding of site, with emphasis on the
hydrogeologic characteristics, in previously unassessed areas at Roxboro and contribute
to the updated Conceptual Site Model.
Schedule
These assessment activities are to be included in the forthcoming CAP. The additional
monitoring well installation activities and sample collection schedule will be dependent
on approval of the proposed plan and an executed E&SC permit. Following NCDEQ
approval of the workplan, SynTerra and Duke Energy will schedule drilling activities.
ATTACHMENTS:
Figure 1: USGS Topographic Map
Figure 2: West Ash Basin Proposed Locations - Southern Extension Impoundment
Table 1: Soil Sample Analytical Methods
Table 2: Anticipated Well Construction Details
Table 3: Groundwater Analytical Methods
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West Ash Basin (WAB) Southern Extension Impoundment (SEI) - Additional Wells February 15, 2019
Roxboro Steam Electric Plant
ATTACHMENTS
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Additional Wells Tech Memo REVISED.docx

0
fir
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HEATED WATER
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NOTES
DUKE ENERGY PROPERTY LINES ARE REPRESENTED BASED
ON HISTORICAL DOCUMENTED PROPERTY BOUNDARIES AND
CURRENT PERSON COUNTY GIS. DUKE ENERGY IS
WORKING TO VERIFY PROPERTY LINE LOCATION IN THE AREA
SOUTHWEST OF THE WEST ASH BASIN SOUTHERN EXTENSION . O
IMPOUNDMENT.
ALL BOUNDARIES ARE APPROXIMATE.
2016 USGS TOPOGRAPHIC MAP, OLIVE HILL QUADRANGLE,
OBTAINED FROM THE USGS STORE AT 0
HTTPS:HSTORE. U SGS. GOV/MAP-LOCATOR.
PERSON COUNTY
WINSTONSALEM
synTerra RALEIGH
CHARLOTTE
148 RIVER STREET, SUITE 220 DRAWN BY: J. V TZ
GREENVILLE, SOUTH CAROLINA 29601 CHECKED BY: K.
PHONE [phone] PROJECT MANAGER: C. EADY
P:\Duke Energy Pmgre 4M�P"80.OAt A\Roxboro\Map_Docs\Miscellaneous\Fig01-01_Roxbom SileLocalion PumpTest_20:
FFDISCHARGE CANAL,/
BASIN
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� EFFLUENT DISCHARGE CANAL
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IMPOUNDMENT 1
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INDUSTRIAL LANDFILL
BOUNDARY
ASH BASIN
COMPLIANCE BOUNDARYcsya
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SOUTHERN EXTENSION
IMPOUNDMENT
1411111
FIGURE 1-1
USGS TOPOGRAPHIC MAP
ROXBORO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
SEMORA, NORTH CAROLINA
DRAWN BY: J. KIRTZ DATE: 2/15/2019 ,000 0 11000 2,00
PROJECT MANAGER: C. EADY CONTOUR INTERVAL: 20 FT
CHECKED BY: K. LAWIN MAP DATE: 2016
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GRAPHIC SCALE IN FEET

LEGEND
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MW-38 BR/
PROPOSED WELL CLUSTER LOCATION (APPROXIMATE)
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MW-18D
WELL IN TRANSITION ZONE
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MW-18BR
WELL IN COMPETENT BEDROCK
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PARCEL LINE DUKE ENERGY (APPROXIMATE)
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— — —
500 ft COMPLIANCE BOUNDARY
APPROXIMATE ASH BASIN WASTE BOUNDARY
APPROXIMATE FREE PONDED ASH BASIN WATER
FLOW DIRECTION
APPROXIMATE POND OR RESERVOIR
0
(NON -JD - JURISDICTIONAL)
APPROXIMATE STREAM (NON -JD - JU RSI DICTIONAL)
SURFACE WATER FLOW DIRECTION
TWT WETLAND APPROVED USACE
®
(USACE #SAW-2014-00189 DATE MAY 16, 2016)
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x SOURCE NOTES:
' NOT ALL UTILITIES ARE IDENTIFIED ON THIS DRAWING. THE UTILITIES SHOWN ON THIS DRAWING ARE VISUAL AIDS TO LOCATE
SF
L THE STREAMS AND WETLANDS IN THE FIELD. THE HORIZONTAL LOCATION AND THE VERTICAL LOCATIONS HAVE NOT BEEN FIELD
LOCATED ON ANY UTILITIES AND THE SHOWN LOCATIONS ARE APPROXIMATE.
TOPOGRAPHY IS BASED ON LIDAR BARE EARTH DATA OBTAINED FROM THE FRIS\NORTH CAROLINA FLOOD RISK INFORMATION SYSTEM
AT http://fris.nc.gov/Eris/Download.aspx?FIPS-031&ST=NC&user=General%2OPublic AND A DRAWING TITLED AERIAL TOPOGRAPHIC
i SURVEY-ROXBORO PLANT BY WSP, JOB NUMBER 1570002.000 AND DRAWING FILE NAME ROXBORO FINAL_06-8-15.DWG
FOR STREAM JURISDICTIONAL STATUS REFER TO THE STREAM CLASSIFICATION TABLE CONTAINED IN THE CURRENT
USACOE ROXBORO STEAM ELECTRIC PLANT JURISDICTIONAL STREAM AND WETLAND SURVEY.
o
DUKE ENERGY PROPERTY LINES ARE REPRESENTED BASED ON HISTORICAL DOCUMENTED PROPERTY BOUNDARIES AND CURRENT
PERSON COUNTY GIS. DUKE ENERGY IS WORKING TO VERIFY THE PROPERTY LINE LOCATION IN THE AREA SOUTHWEST OF THE WEST
ASH BASIN SOUTHERN EXTENSION IMPOUNDMENT.
MW-38 BR/D/S
PROPOSED LOCATION ON THIS FIGURE IS
APPROXIMATE AND MEANT TO REPRESENT A
GENERAL AREA FOR THE WELL CLUSTER
LOCATION. THE ACTUAL WELL CLUSTER
LOCATION WILL BE DEFINED BASED ON SITE
TOPOGRAPHY AND FEASIRI F AGGESS Rol ITR
DUKE
ENER
PROGRE;
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SS synTerra
l
d
250 GAPHICSC200
00500 FIGURE 2
IN FEET WEST ASH BASIN PROPOSED LOCATIONS
148 RIVER STREET, SUITE 220
GREENVILE,SOUTH CAROLINA 29601 SOUTHERN EXTENSION IMPOUNDMENT
PHONE 86rracor .com ADDITIONAL WELLS
999
www.synterracorp.com m
DRAWN BY: J. CHASTAIN DATE:2/11/2019 ROXBORO STEAM ELECTRIC PLANT
PROJECT MANAGER: C.
LAYOUT: PCR14159 (DDATTAAGAP WELL) SEMORA, NORTH CAROLINA
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TABLE 1
SOIL SAMPLE ANALYTICAL METHODS
ROXBORO STEAM ELETRIC PLANT
DUKE ENERGY PROGRESS LLC, ROXBORO, NC
INORGANIC COMPOUNDS
UNITS
METHOD
Aluminum
mg/kg
EPA 6010D
Antimony
mg/kg
EPA 6020B
Arsenic
mg/kg
EPA 6020B
Barium
mg/kg
EPA 6010D
Beryllium
mg/kg
EPA 6010D
Boron
mg/kg
EPA 6010D
Cadmium
mg/kg
EPA 6020B
Calcium
mg/kg
EPA 6010D
Chloride
mg/kg
EPA 9056A
Chromium
mg/kg
EPA 6010C
Cobalt
mg/kg
EPA 6020A
Copper
mg/kg
EPA 6010C
Iron
mg/kg
EPA 6010C
Lead
mg/kg
EPA 6020B
Magnesium
mg/kg
EPA 6010D
Manganese
mg/kg
EPA 6010C
Mercury
mg/kg
EPA 7471B
Molybdenum
mg/kg
EPA 6010D
Nickel
mg/kg
EPA 6010C
Nitrate as Nitrogen
mg/kg
EPA 9056A
pH
SU
EPA 9045D
Potassium
mg/kg
EPA 6010D
Selenium
mg/kg
EPA 6020B
Sodium
mg/kg
EPA 6010D
Strontium
mg/kg
EPA 6010C
Sulfate
mg/kg
EPA 9056A
Thallium
mg/kg
EPA 6020B
Total Organic Carbon
mg/kg
EPA 9060
Vanadium
mg/kg
EPA 6020B
Zinc
I mg/kg
IEPA 6010C
Prepared by: RBI Checked by: SRW/TCP/VTV
Notes:
1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045, as noted
above.
2. Analytical methods and reporting limits as presented were developed for CSA field implementation in 2015. Analytical methods and
reporting limits are updated periodically and applied as appropriate.
mg/kg - Milligrams per kilogram
S.U. - Standard Unit
P:\Duke Energy Progress. 1026�_ADMINISTRATIVE\Financial Management\Project Change Requests (PCRs)\Roxboro\Quote 14159 - SEI
Data Gap Wells\Tech Memo\Table 1 Soil Sample Analytical Methods Page 1 of 1

TABLE 2
ANTICIPATED WELL CONSTRUCTION DETAILS
WEST ASH BASIN SOUTHERN EXTENSION IMPOUNDMENT ADDITIONAL MONITORING WELLS
ROXBORO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, SEMORA, NC
Proposed Total
Proposed Well
Well ID
Assessment Area
Borehole Depth
Screened Interval
Intended Purpose
Well Screen Location
Preferred Drilling Method
(feet bgs)1, 2
(feet bgs)1,2
MW-38BR
Southern
130
120-130
Vertical delineation
Upper Bedrock
Hollow -Stem Auger/Air Rotary/Coring or Sonic
MW-38D
Extension
80
70-80
Horizontal delineation
Transitional Zone
Hollow -Stem Auger/Air Rotary/Coring or Sonic
Impoundment
40
30-40
MW-385
Horizontal delineation
Surficial/Saprolite
Hollow -Stem Auger/Air Rotary/Coring or Sonic
MW-39BR
Southern
130
120-130
Vertical delineation
Upper Bedrock
Hollow -Stem Auger/Air Rotary/Coring or Sonic
MW-39D
Extension
80
70-80
Horizontal delineation
Transitional Zone
Hollow -Stem Auger/Air Rotary/Coring or Sonic
MW-39S
Impoundment
40
30-40
Horizontal delineation
Surficial/Saprolite
Hollow -Stem Auger/Air Rotary/Coring or Sonic
Prepared by: KTL Checked by: CDE
Notes:
'Proposed well depths based on well construction information from wells MW-18BR and MW-18D.
2Proposed boring depths and screened intervals are estimates; actual screened intervals and total boring depths will be determined based on field observations and approved by a NC Licensed Geologist.
PADuke Energy Progress.1026\_ADMINISTRATIVE\Financial Management\Project Change Requests (PCRs)\Roxboro\Quote 14159 - SEI Data Gap Wells\Tech Memo\Table 2 Anticipated Well Construction
Details

TABLE 3
GROUNDWATER ANALYTICAL METHODS
ROXBORO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS LLC, ROXBORO, NC
PARAMETER RL UNITS METHOD
FIELD PARAMETERS
H
NA
SU
Field Water Quality Meter
Specific Conductance
NA
µS/Cm
Field Water Quality Meter
Temperature
NA
oC
Field Water Quality Meter
Dissolved Oxygen
NA
m L
Field Water Quality Meter
Oxidation Reduction Potential
NA
mV
Field Water Quality Meter
Eh
NA
mV
Field Water Quality Meter
Turbidity
NA
NTU
Field Water Quality Meter
INORGANICS
Aluminum
0.005
m L
EPA 200.7 or 6010D
Antimony
0.001
m L
EPA 200.8 or 6020B
Arsenic
0.001
m L
EPA 200.8 or 6020A
Barium
0.005
m L
EPA 200.7 or 6010C
Beryllium
0.001
m L
EPA 200.8 or 6020A
Boron
0.05
m L
EPA 200.7 or 6010C
Cadmium
0.001
m L
EPA 200.8 or 6020A
Chromium
0.001
m L
EPA 200.8 or 6010C
Cobalt
0.001
m L
EPA 200.8 or 6020A
Copper
0.001
m L
EPA 200.8 or 6020B
Hexavalent Chromium
0.000025
m L
EPA 218.7
Iron
0.01
m L
EPA 200.7 or 6010C
Lead
0.001
m L
EPA 200.8 or 6020A
Manganese
0.005
m L
EPA 200.7 or 6010C
Mercury
0.000
m L
EPA 245.1 or 7470A
Molybdenum
0.001
m L
EPA 200.8 or 6020E
Nickel
0.001
m L
EPA 200.8 or 6020B
Selenium
0.001
m L
EPA 200.8 or 6020A
Strontium
0.005
m L
EPA 200.7 or 6010C
Thallium low level
0.0002
m L
EPA 200.8 or 6020A
Vanadium low level
0.0003
m L
EPA 200.8 or 6020A
Zinc
0.005
m L
JEPA 200.7 or 6010C
RADIONUCLIDES
Radium 226
1
Ci/L
EPA 903.1 Modified
Radium 228
1
O/L
EPA 904.0/SW846 9320 Modified
Uranium 223 234 236 238
Varies by Isotope
µg/mL
SW846 3010A/6020B
Total Uranium
NA
µg/mL
Calculated
ANIONS/CATIONS
Alkalinity as CaCO3
5
m L
SM 2320B
Bicarbonate
5
m L
SM 2320
Calcium
0.01
m L
EPA 200.7
Carbonate
5
m L
SM 2320
Chloride
0.1
m L
EPA 300.0 or 9056A
Magnesium
0.005
m L
EPA 200.7
Potassium
0.1
m L
EPA 200.7
Sodium
0.05
m L
EPA 200.7
Sulfate
0.1
m L
EPA 300.0 or 9056A
Sulfide
0.1
mg/L
SM4500S2-D
Total Dissolved Solids
25
m L
SM 2540C
Total Or 29ic Carbon
0.1
m L
SM 5310C EPA9060A
Total Sus ended Solids
1 2.5
1 m L
ISM 2450D
Prepared by: RBI Checked by: SRW TCP
Notes:
1. Select constituents will be analyzed for total and dissolved concentrations.
2. Analytical methods and reporting limits as presented were developed for CSA field implementation in 2015. Analytical methods and reporting limits are updated periodically and applied
as appropriate.
OC - Degrees Celsius
VS/cm = micro -Siemens per centimeter
mg/L - Milligrams per liter
mg - N/L - Milligrams nitrogen per liter
mV - Millivolts
NA - Not analyzed
NTU - Nephelometric turbidity unit
pCi/L - picocuries per liter
RL = reporting limit
S.U. - Standard Unit
ug/mL - micrograms per milliliter
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Analytical Methods Page 1 of 1