NC0004774_SOC (Acknowledgement)_20220426 (2)

FIECEIVED/NCDEQ/DWR
APR 2,9 2022 James Wells
Vice President
Environmental, Health and Safety
WQROSPrograms & Environmental Sciences
MOORESVILLE REGIONAL OFFt ESouth Church Street
Charlotte, NC 28202
[phone]
April 26, 2021
C k Basinger,`
Mooresville Regional Supervisor
North Carolina Department of Environmental Quality
Division of Water Resources
610 East Center Avenue
Mooresville, NC 28115
Bob Sledge
North Carolina Department of Environmental Quality
Water Quality Permitting Program
Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Report Under Special Order by Consent — EMC SOC WQ S18-004
Duke Energy Carolinas, LLC — Buck Steam Station
NPDES Permit NC0004774
2021 Annual Seep Survey Report
Dear Messrs. Basinger and Sledge:
On behalf of Duke Energy Carolinas, LLC (DEC), I am submitting to you the Buck Steam
Station Annual Seep Survey Report as required by Section 2.b.3 of the subject Special Order by
Consent (SOC).
As required by the SOC, I certify under penalty of law that this document and all attachments were
prepared under my direction or supervision in accordance with a system designed to assure that
qualified personnel properly gather and evaluate the information submitted. Based on my inquiry
of the person or persons who manage the system, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and belief
true, accurate, and complete. I am aware that there are significant penalties for submitting false
information, including the possibility of fine and imprisonment for knowing violations.

Messrs. Basinger and Sledge
April 26, 2021
Page 2
Please direct any questions concerning the Buck Steam Station's SOC No. S 18-004 to Shannon
Langley at [phone] or [e-mail].
Sincerely,
James Wells
Vice President, Environmental, Health & Safety
Programs and Environmental Sciences
Duke Energy
Attachment
Buck Steam Station 2021 Annual Seep Survey
CC: Jessica Bednarcik, Duke Energy
Richard Baker, Duke Energy
Steve Cahoon, Duke Energy
Dale Wooten, Duke Energy
Matt Hanchey, Duke Energy
Shannon Langley, Duke Energy

Science & Engineering Consultants
2021 ANNUAL SEEP REPORT
BUCK STEAM STATION
EMC SOC WQ S18-004
1555 DuKEVILLE ROAD
SALISBURY, NC 28146
APRIL 2022
PREPARED FOR
CAROLINAS
DUKE ENERGY CAROLINAS, LLC
Kathry W. Webb
SeAior Peer Reviewer
synterracorp.com
1SBBBEBPItpff
CA 114kpject Manager
Tim Grant
Cril tTi ttell, NC L.G. #2426
Project Principal

2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION 1-1
2.0 FINDINGS 2-1
2.1 General Observations 2-1
2.2 Effects of Decanting 2-1
2.3 Changes to Seep Status 2-1
3.0 REFERENCES 3-1
LIST OF FIGURES
Figure 1 Seep Locations and Inspection Areas
LIST OF TABLES
Table 1 Seep Locations and Descriptions — December 2021 Inspection
UST OF APPENDICES
Appendix A Photographs
April 2022 Page i
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2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
1.0 INTRODUCTION
On December 6, 2021, Chris Suttell (NC L.G. #2426) of SynTerra inspected the Buck Steam
Station (Buck or Site) property for existing and potential new seeps. General observations
include:
• Previously unidentified seeps were not observed during the inspection.
• Notable changes to seeps were not observed during the inspection.
• River stage and water levels in streams were lower than those during previous
inspections.
Inspection activities were performed in accordance with North Carolina Environmental
Management Commission (EMC) Special Order by Consent (SOC) WQ #518-004. The SOC
describes inspection requirements as follows:
Duke Energy shall conduct annual comprehensive surveys of areas down gradient
of ash basins identifying new seeps, and documenting the physical characteristics
of previously documented seeps. All examinations of seeps must include
identification of seeps by approximate latitude and longitude and date -stamped
digital photographs of their appearance. A report summarizing the findings of the
surveys, including a section analyzing the effect decanting of the basin(s) has on
seep flows, accompanied by copies of the photographs noted above ("Annual Seep
Report"), shall be submitted to DWR in conjunction with submittal of the April 30
quarterly report noted in 2(c)(2) above. This Annual Seep Report must list any seep
that has been dispositioned (as described below) during the previous year,
including an analysis of the manner of disposition.
All locations listed in Table 1 of the SOC were observed and documented with photographs
during the inspection.
During the inspection, no rainfall occurred and the temperature ranged from 61 to 68 degrees
Fahrenheit (F) under partly cloudy skies with a steady breeze. According to the information
from the on -Site rain gauge, there was no recorded rainfall at the Site in the 5-day period
before the inspection.
The inspector reviewed previous seep inspection reports and the weekly dam safety inspection
reports pertaining to each ash basin from the 2 weeks preceding the seep inspection. Kyle
Baucom and Michael Lazar of Duke Energy prepared those dam safety inspection reports.
Observations from the dam safety inspection reports were consistent with observations made
during the annual inspection.
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2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
The inspection included observations in the following areas (Figure 1):
• North and east of Ash Basin Cells 2 and 3, along the Yadkin River
• Along the tributary located east of Ash Basin Cells 2 and 3
• Along the tributary located west of Ash Basin CeII 1
• Between the Combined Cycle Station and Ash Basin Cell 1, along the dam
• Areas along and downgradient of the ash basin dams
Seep locations and inspection areas are illustrated on Figure 1. Observations noted during the
inspection are summarized on Table 1. Photographs of each seep location, taken during the
inspection, are included in Appendix A.
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2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
2.0 FINDINGS
2.1 General Observations
Inspection observations of each seep are shown in Table 1. Details include the following:
• New seeps were not observed during the inspection.
• Previously unidentified or unreported pipes were not observed during this inspection.
• River stage and water levels in streams were lower than those during previous
inspections.
• Seeps were generally dryer than previously observed conditions.
• Dry conditions were observed at S-16.
• Stagnant conditions were observed at 5-01, 5-07, 5-08, 5-11, S-12, 5-13, and 5-15.
• Trickle flow was observed at S-05, S-14, and S-17.
• Steady flow was observed at S-02, 5-03, S-04, S-06, S-09, and S-10.
2.2 Effects of Decanting
Ash basin decanting was initiated on February 7, 2019. Decanting was completed on March 2,
2020, as described in the Notification of Decanting Completion letter to the North Carolina
Department of Environmental Quality (NCDEQ) Division of Water Resources (DWR), dated April
2, 2020. Dewatering of the ash basins was initiated after the completion of decanting and is
ongoing.
As noted in the 2020 Annual Seep Report, decanting of Ash Basin Cell 1 has reduced seep flow
north and west of Cell 1. The 2020 Annual Seep Report also noted that decanting has not
significantly reduced seep flow north of Ash Basin Cells 2 and 3. While conditions during the
December 2021 seep inspection were slightly drier than during the 2020 (post -decanting) seep
inspection, seep flows in these areas were generally consistent during both inspections.
2.3 Changes to Seep Status
Mr. Suttell inspected each seep to evaluate whether it met the requirements to be
dispositioned in accordance with the SOC. The requirements for dispositioning a seep are as
follows:
For purposes of this Special Order, "dispositioned" includes the following: (1) the
seep is dry for at least three consecutive quarters; (2) the seep does not constitute,
and does not flow to, waters of the State or Waters of the United States for three
consecutive quarters; (3) the seep is no longer impacted by flow from any coal ash
basin as determined by the Director of DWR in accord with applicable law and best
professional judgment; or (4) the seep has been otherwise eliminated (e.g.,
through an engineering solution). If a seep that has been dispositioned through
April 2022
Page 2.1
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2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
drying up reappears in any subsequent survey, such a seep will no longer be
deemed dispositioned and can be subsequently re-dispositioned as specified
above. Non -constructed seeps described in paragraph 1(h) of this SOC cannot be
dispositioned through option (2) above.
No seeps were dispositioned or removed from the status of dispositioned during the calendar
year of 2021.
April 2022 Page 2-2
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2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
3.0 REFERENCES
North Carolina Department of Environmental Quality. (2018). Special Order by Consent EMC
SOC WQ S18-004.
April 2022
Page 3-1
Project: 00.0081.31

2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
FIGURE
Science & Engineering Consultants

2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
TABLE
Science & Engineering Consultants

Notes from December 2021 Inspection
Stagnant water present in channel, no active flow.
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Steady moderate flow within well defined tributary to Yadkin River. Water is
clear. Consistent with previous inspection.
Channel is saturated at the sign location. Flow infiltrates underground and re-
emerges twice along channel at lower elevations before flowing overland
towards Yadkin River. Consistent with previous inspection.
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Steady moderate flow in creek at the sign location. Water is clear. Infiltrates
and re-emerges several times. Consistent with previous inspection.
Stagnant pool of water at culvert outlet. No flow observed toward Yadkin
River.
Stagnant pool of water at sign. Low flow within the tributary stream leading to
the Yadkin River. Water is clear. Consistent with previous inspection.
Moderate flow within relatively wide, shallow channel. Water is clear.
Consistent with previous inspection.
Moderate flow from berm along Dukeville Rd. downgradient from the
Beneficiation Plant. Clear water. Consistent with previous inspection.
Interim Action Levels
NA - 02 B Standards Apply
NA - Seep Dispositioned
NA - Seep Dispositioned
Hardness 200 mg/L
Mercury 0.1 pg/L
pH 6-10 S.U.
Hardness 200 mg/L
NA - Seep Dispositioned
NA - Seep Dispositioned
Hardness 200 mg/L
NA - Seep Dispositioned
NA - Seep Dispositioned
SOC Monitoring
Monitoring at point prior
to any tributary flow to
UT
NA - Seep Dispositioned
NA - Seep Dispositioned
Monitoring at point prior
to entering Yadkin River
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NA - Seep Dispositioned
NA - Seep Dispositioned
Monitoring at established
Duke Energy SA8
monitoring site.
NA - Seep Dispositioned
NA - Seep Dispositioned
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Seep to UT that flows north to Yadkin River in approximately 2 foot
wide channel. Located northeast of the ash basin, north of Leonard
Road.
Located northeast of the ash basin, north of Leonard Road. Flows
north to Yadkin River via approximately 4.5 foot wide stream. From
sampling - No CCR impacts.
Located northeast of the ash basin, north of Leonard Road. Flows
north to Yadkin River via approximately 8.5 foot wide stream. From
sampling - No CCR impacts.
Seep to approximately 2 foot wide channel, located northeast of the
ash basin, north of Leonard Road. Stream flows east to Yadkin River.
Seep to short UT below storm water culvert near toe of ash basin
dam. UT may receive flow from 5-14 prior to reaching Yadkin River.
Approximately 4 foot wide stream located north of ash basin, east of
decommissioned Buck Steam Station facility. Flows north toward
Yadkin River. From sampling- No CCR impacts.
Approximately 3.5 foot wide stream, located northwest of the ash
basin, west of Dukeville Road. Flows northwest to Yadkin River. From
sampling - No CCR impacts.
Seep to approximately 1 foot wide channel, located northwest of the
ash basin, west of Dukeville Road. Flows northwest to Yadkin River.
Sampling location; not a seep
Approximately 2 foot wide stream, located west of the ash basin, west
of Dukeville Road. Flow is to Yadkin River. From sampling - No CCR
impacts.
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UT to Yadkin River
UT to Yadkin River
UT to Yadkin River
UT to Yadkin River
UT to Yadkin River
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UT to Yadkin River
Buck Steam
Station S-10• 35.702188-80.376455 UT to Yadkin River
Location Coordinates
Longitude
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35.710382
35.712239
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Seep ID Number
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Buck Steam
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Notes from December 2021 Inspection
Stagnant water in manhole was below level of the culvert inlet. No observed
overland flow in area. Water is relatively clear. Consistent with previous
inspection.
Seep eliminated via engineering controls. Manhole with stagnant water
present below level of culvert inlet. No observed overland flow in area.
Consistent with previous inspection.
Area of saturated soil and very minor standing water near sign. Minor trickle
',. observed discharging from culvert downgradient of 5-13 sign.
Trickle of flow from the culvert- Consistent with previous inspection.
Saturated soil and some standing water near sign. Diffuse flow toward Yadkin
River.
Seep eliminated via engineering controls. Area inspected, but seep no longer
exists. Consistent with previous inspection.
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Interim Action Levels
See Page 4 of Buck SOC
Document Attachment A
NA - Seep Dispositioned
NA Seep Dispositioned
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See Page 4 of Buck SOC
Document Attachment A
SOC Monitoring
NA - Monitoring
Established per Terms of
NPDES Permit
NA - Seep Dispositioned
NA - Seep Dispositioned
Monitoring at established
Duke Energy 5-05
monitoring site
Monitoring at established
Duke Energy 5-05
monitoring site
NA - Seep Dispositioned
NA - Monitoring
Established per Terms of
NPDES Permit
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Seep discharge front terracotta pipe to riprapped channel on north
dike wall of ash basin. Flow conveyed to UT to the Yadkin River.
Channeled seep through a terracotta pipe. Pipe has been plugged;
discharge eliminated.
Minimal AOW with no flow. Identified as a damp area near pump
house; insufficient flow to perform sampling. Any flow would move to
adjacent storm drain.
Low flow seep near storm water culvert just above 5-05 location. Flow
moves to UT to Yadkin River near 5-05.
Low flow seep downgradient of 5-05 location. Seep flows to braided,
short reach UT prior to entering Yadkin River.
Static area of wetness along west dike wall of ash basin. Flow would
drain toward 5-09 sampling site. Location has been repaired since
area of wetness no longer exists.
Filter blanket discharge from west dike wall of ash basin. Flow
conveyed to UT to the Yadkin River.
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Location Coordinates
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2y 2

2021 Annual Seep Report
Buck Steam Station
Salisbury, NC
APPENDIX A
PHOTOGRAPHS
Science & Engineering Consultants

2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Non -Constructed Seep — View facing northeast
December 2021 Photos
Page 1
Project: 00.0081.31

2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Dispositioned Seep — View facing southeast
December 2021 Photos
Page 2
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
Dispositioned Seep — View facing east
December 2021 Photos
Page 3
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-04
Non -Constructed Seep — View facing west
December 2021 Photos
Page 4
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Salath Elevation
Non -Constructed Seep — View facing north
December 2021 Photos
Page 5
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-06
-- Piorth East:Eleva
Dispositioned Seep — View facing southwest
December 2021 Photos
Page 6
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
-: South East EEevation-
Dispositioned Seep — View facing northwest
December 2021 Photos
Page 7
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Non -Constructed Seep — View facing south
December 2021 Photos
Page 8
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Dispositioned Seep — View facing south
December 2021 Photos
Page 9
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
Dispositioned Seep — View facing southeast
December 2021 Photos
Page 10
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
South East Efevation
NPDES Constructed Seep — View facing northwest
December 2021 Photos
Page 11
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-12 Dispositioned Seep — View facing west
December 2021 Photos
Page 12
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
Dispositioned Seep — View facing northwest
December 2021 Photos
Page 13
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-14
Non -Constructed Seep — View facing west
December 2021 Photos
Page 14
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
Non -Constructed Seep — View facing northeast
December 2021 Photos
Page 15
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2021 Annual Seep Report —Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-16
Dispositioned Seep — View facing northwest
December 2021 Photos
Page 16
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2021 Annual Seep Report — Appendix A Photographs
Buck Steam Station
Salisbury, NC
S-17 NPDES Constructed Seep — View facing west
December 2021 Photos
Page 17
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