NC0004979_Annual Report_20200423

( DUKE RECEIVED James Wells
Vice President
ENERGY. MAY 01 2020 Environmental,Health and Safety
Programs&Environmental Sciences
526 South Church Street
C
NCDEQIDWRINPDES Charlotte,80)373-29646
646
April 23, 2020
Via Overnight Mail
Laserfiche
Corey Basinger
Mooresville Regional Office Regional Supervisor
North Carolina Department of Environmental Quality
Division of Water Resources
Water Resources -Water Quality Regional Operations
610 East Center Avenue, Suite 301
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 S 17-009
Duke Energy Carolina, LLC—Allen Steam Station
NPDES Permit NC0004979
2019 Annual Seep Survey Report
Dear Messrs. Basinger and Sledge:
On behalf of Duke Energy Carolinas, LLC (DEC), I am submitting to you the Allen Steam Station
Annual Seep Report summarizing the findings of the comprehensive survey as required by the
Allen Steam Station NPDES Permit NC0004979 Special Order by Consent(SOC), SOC No. S 17-
009 Section 2.c.3).
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 23, 2020
Page 2
Please direct any questions concerning the Allen Steam Station NPDES Permit NC0004979 SOC
No. S 17-009 to Robert Wylie at [phone] and to Chris Hallman at [phone] relative
to the annual seep inspection report.
Sincerely,
James ells
Vice P sident, Environment, Health & Safety-
Programs and Environmental Sciences
Duke Energy
Attachment:
Allen Steam Station 2019 Annual Seep Survey
CC: Richard Baker, Duke Energy
Robert Wylie, Duke Energy
Chris Hallman, Duke Energy
Randy Gantt, Duke Energy
Paul Draovitch, Duke Energy
Matt Hanchey, Duke Energy

synlérra
2019 ANNUAL SEEP REPORT
ALLEN STEAM STATION
EMC SOC WQ S17-009
253 PLANT ALLEN ROAD
BELMONT, NC 28012
APRIL 2020
PREPARED FOR
DUKE
ENERGY.
CAROU
DUKE ENERGY CAROLINAS, LLC
Leonard W. Drago
Staff Scientist
Ch ' toph . Suttell, NC LG #2426
Project Principal

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas, LLC SynTerra
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION 1-1
1.1 Inspection Details 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 SOC Locations and Inspection Areas
LIST OF TABLES
Table 1 SOC Locations and Descriptions—February 2019
LIST OF APPENDICES
Appendix A Photographs
Page i

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
LIST OF ACRONYMS
EMC Environmental Management Commission
SOC Special Order by Consent
Page ii

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
1.0 INTRODUCTION •
On February 26, 2019, SynTerra (Chris Suttell, NC L.G. #2426) inspected the Allen
Steam Station (Allen or Site) property for existing and potential new seeps. No changes
to seep status were observed. Inspection activities were performed in accordance with
North Carolina Environmental Management Commission (EMC) Special Order by
Consent (SOC) WQ #S17-009. 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 [Department
of Water Resources] 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.
General observations include:
• No previously unidentified seeps were observed during the inspection
• No notable changes to existing seep status were observed during the inspection
• Decanting had not begun at the time of this inspection
• Notable shoreline erosion was observed
1.1 Inspection Details
The weather was partly cloudy before and during the inspection. Temperatures ranged
from approximately 37 to 65 degrees Fahrenheit(F). No precipitation was recorded on
the day of the inspection. A total of 1.62 inches of precipitation was recorded during the
four-day period prior to the inspection at the on-Site weather station.
The inspector reviewed previous seep inspection reports and the weekly dam safety
inspection reports for each ash basin. Mr. Scott Harris (Duke Energy system owner)
conducted the ash basin dam safety inspections and prepared the reports. Mr. Harris,
Page 1-1

6
2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
• Ms. Mary Parlemon (Duke Energy CCP Field Support) and Mr. Chris Hallman (Duke
Energy Subject Matter Expert) were interviewed about recent rainfall amounts, recent
construction/stabilization projects associated with the ash basins and general Site
conditions in and surrounding the ash basins. Observations from the dam safety
inspection reports were consistent with observations made during the annual
inspection.
The inspection included the following areas (Figure 1):
• The east dam,between the coal pile and retired ash basin
• The north dike, between the retired ash basin and the active ash basin
• The east dam, between Lake Wylie and the retired ash basin
• The east dam, between Lake Wylie and the active ash basin
• South and southeast of the active ash basin, extending to Lake Wylie
Seep locations and inspection areas are shown on Figure 1. Observations noted during
the inspection are summarized on Table 1. Photographs taken of each seep location
during the inspection are included in Appendix A.
Page 1-2

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
2.0 FINDINGS
2.1 General Observations
Inspection observations of each seep are shown in Table 1. Details include:
• No new seeps were observed during the inspection
• No previously unidentified or unreported pipes were observed during
inspection
• Conditions were similar as those reported in recent Dam Safety Inspection
Reports
• Water levels were higher than observed during previous seep inspection due to
above average rainfall during the months prior to the inspection
• Flow at S-2 was steady and greater than that observed during previous
inspection
• Notable shoreline erosion had occurred since the previous inspection in June
2018
2.2 Effects of Decanting
Decanting of the ash basin at Allen had not begun at the time of this inspection.
2.3 Changes to Seep Status
Mr. Suttell inspected each seep to evaluate whether it met 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 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 changes to seep status were observed during this inspection.
Page 2-1

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC K:; SynTerra
•
FIGURES

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
• 3.0 REFERENCES
North Carolina Department of Environmental Quality. (2018). Special Order by Consent
EMC SOC WQ S17-009.
Page 3-1

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-. Toe Drain
+ 1 1 ` Outfall 108B
LEGEND ., : ` (S-88)
NPDES CONSTRUCTED SEEPS "� �` S-7
(APPROXIMATE) ' � `
SOC NON-CONSTRUCTED SEEP ' ACTIVE +- IS-6
SH BASIN
(APPROXIMATE) '" � &5
SEEP DISPOSITIONED BY SOC � Toe Drain
(APPROXIMATE) I Outfall 104
ACTIVE ASH BASIN WASTE BOUNDARY ` (S-4)
RETIRED ASH BASIN WASTE BOUNDARY . Toe Drain
r �Outfall 103
!t
ASH BASIN COMPLIANCE BOUNDARY -
,,.` (S-3)
I RETIRED ASH BASIN ASH LANDFILL WASTE ,` ' r=`'
BOUNDARY ;s,-,,
RETIRED ASH BASIN ASH LANDFILL • !,•4 '` o .� g} r#
COMPLIANCE BOUNDARY
DORS FILLS BOUNDARIES , �, 6 r, E S-2
. DUKE ENERGY CAROLINAS PROPERTY LINE Y `�
SPECIAL ORDER BY CONSENT(SOC) I . � µ 4 f
INSPECTION AREA ' `
)► STREAM(AMEC NRTR 2015) t �'�
��
•
WETLAND(AMEC NRTR 2015) ` /
SURFACE WATER FLOW DIRECTION • ."' , �'� a
V�
NOTES: I
1.SPECIAL ORDER BY CONSENT(SOC)LOCATIONS ARE DESCRIBED IN `
EMC SOC WO S17-009.
2.NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM(NPDES) (a .1„
LOCATIONS ARE DESCRIBED IN PERMIT NC0004979 W . ,x ,. 1 ff
3.SAMPLE LOCATIONS WERE DERIVED FROM VARIOUS SOURCES AND -� - `*�^n+ -
ARE A MIX OF SURVEYED AND APPROXIMATE LOCATIONS.THEREFORE, ' """ ± r `• .'
SAMPLE LOCATIONS ARE TO BE DEEMED APPROXIMATE. - ;.' , 1 t ,
4.THE WATERS OF THE U.S.DELINEATION HAS NOT BEEN APPROVED BY s, n
THE U S ARMY CORPS OF ENGINEERS AT THE TIME OF THE MAP .. } v..: ti+ "
CREATION.THIS MAP IS NOT TO BE USED FOR JURISDICTIONAL ` `"" - ° ' r' "" ".
DETERMINATION PURPOSES.THE WETLANDS AND STREAMS ',j x.
BOUNDARIES WERE OBTAINED FROM STREAM AND WETLAND _ -. -
DELINEATION CONDUCTED BY AMEC FOSTER WHEELER 400 0 400 800
ENVIRONMENTAL 8 INFRASTRUCTURE,INC.NATURAL RESOURCE .�DUKE TECHNICAL REPORT(NRTR)FOR ALLEN STEAM STATION DATED MAY 29, •t FIGURE 1
2015. GRAPHIC SCALE IN FEET
ENERGYSOC LOCATIONS AND INSPECTION AREAS
5 PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. i.',4.POUN A5
6 ALL BOUNDARIES ARE APPROXIMATE. DRAWN BY: K.KING DATE:04/10/2019 2019 ANNUAL SEEP REPORT
REVISED BY:C.WYATT DATE:03/26/2020
7 AERIAL PHOTOGRAPHY OBTAINED FROM GOGGLE EARTH PRO ON 0CHECKED BY:T.HARTMAN DATE:03/26/2020 A L L E N STEAM STATION
DECEMBER 13,2018.AERIAL WAS COLLECTED ON MARCH 30,2018. APPROVED BY:L.DRAGO DATE:03/26/2020 g E LM O NT
- 8 DRAWING HAS BEEN SET WITHA PROJECTION OF NORTH CAROLINA synTerra PROJECT MANAGER:C.SUTTELL , NORTH CAROLINA
STATE PLANE COORDINATE SYSTEM FIPS 3200(NAD83). W W W.SYrlterraCOrp.COrT1

•
2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
TABLES

TABLE 1
SOC LOCATIONS AND DESCRIPTIONS - FEBRUARY 2019
2019 ANNUAL SEEP REPORT
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
Location Coordinates Receiving
Facility Sample ID Receiving Waterbody Description SOC Monitoring Interim Action Levels Notes from Inspection
Waterbody
Latitude Longitude Classification
Catawba River Located south of active ash basin. Flow is in
Allen S-1* 35.170632 -81.010093 WS-V; B approximately 3 foot wide channel flowing southeast NA - Seep Dispositioned NA - Seep Dispositioned Stream flowing at a trickle. Water emerges from face of the bank at a steady
(Lake Wylie) trickle.
to Lake Wylie. Via sampling - No CCR impacts
Located south of active ash basin at toe of dike.
Catawba River Monitoring at point prior to pH 5-10 S.U. Steady flow. Orange aerobic bacteria/floc/iron-oxidation apparent on substrate.
Allen S-2 35.173761 -81.00578 (Lake Wylie) WS-V; B Flows to approximately 3 foot wide channel that entering Lake Wylie Hardness 400 mg/L Uninterrupted and discharges into Lake Wylie.
flows to Lake Wylie
Located east of active ash basin, between dike and Moderate and steady flow that emerges from low areas at the east toe of the
Catawba River Instream Monitoring of
Allen S-5 35.17698 -81.006087 (Lake Wylie) WS-V; B river bank. Intermittent, unconfined diffuse flow Lake Wylie NA - 2B Standards Apply active ash basin that is captured by a toe drain system (rip rap blanket) and
towards Lake Wylie. channeled toward Lake Wylie. No apparent discoloration of water or substrate.
Located east of active ash basin, between dike and
Catawba River Instream Monitoring of Steady flow.
Allen S-6 35.177049 -81.006128 WS-V; B river bank. Intermittent, unconfined diffuse flow NA - 2B Standards Apply
(Lake Wylie) towards Lake Wylie. Lake Wylie No apparent discoloration of water or substrate.
Located east of active ash basin, between dike and Slow steady flow observed from boat.
Catawba River Instream Monitoring of
Allen S-7 35.177736 -81.006334 (Lake Wylie) WS-V; B river bank. Intermittent, unconfined diffuse flow Lake Wylie NA - 2B Standards Apply From land, no flowing water is apparent.
towards Lake Wylie. No apparent discoloration of water or substrate.
Allen S-9** 35.185838 -81.00585 Catawba River WS-V; B Former seep with flow through 24" corrugated metal NA - Seep p Dis ositioned NA - SeepDispositioned Dispositioned.Wylie) pipe. Pipe has been grouted; discharge eliminated. P p ositioned. No apparent flow.
NPDES locations
Toe Drain Moderate and steady flow that emerges from low areas at the east toe of the
Catawba River NA - Monitored per terms of active ash basin that is captured by a toe drain system (rip rap blanket) and
Allen Outfall 103 (S- 35.1752 -81.006 (Lake Wylie) WS-V; B Constructed toe drain. the NPDESpermit NA- 2B Standards Apply
3) channeled toward Lake Wylie. Slight iron-oxidizing bacteria on substrate and
biofilm on headwaters and within stream.
•
Toe Drain Moderate and steady flow that emerges from low areas at the east toe of the
Allen Outfall 104 (S 35.17569 81.00606 Catawba River WS-V; B Constructed toe drain. NA - Monitored per terms of NA 2B Standards Apply active ash basin that is captured by a toe drain system (rip rap blanket) and
4) (Lake Wylie) the NPDES permit channeled toward Lake Wylie. Water is generally clear but has some biofilm on
the water surface and orange iron-oxidizing bacteria observed on substrate.
Toe Drain Catawba River NA- Monitored per terms of Flow that emerges from low areas at the east toe of the active ash basin that is
Allen Outfall 108 (S- 35.1785 -81.0064 Wylie) WS-V; B Constructed toe drain. NA- 2B Standards Apply
8) (Lake the NPDES permit captured within a 12-inch metal culvert draining toward Lake Wylie.
Toe Drain Catawba River NA - Monitored per terms of Flow that emerges from low areas at the east toe of the active ash basin toward
Allen Outfall 108B 35.17816 -81.006517 WS-V; B Constructed toe drain. NA - 2B Standards Apply
(S 8B) (Lake Wylie) the NPDES permit a culvert directed away from dike toward Lake Wylie.
Prepared by: KDF Checked by: GTC
Notes; Revised by: CBC Checked by: LWD
* -Location previously investigated as a seep.Monitoring has not indicated the presence of coal combustion residuals.
**-Seep dispositioned via repair and/or non-flowing condition to potentially reach Waters of the U.S.,or other,as noted.Monitoring shall be conducted at the approximate locations indicated on the attached site map.
All monitoring shall be conducted per the requirements found in Attachment B of this Order.
Special Order by Consent(SOC)descriptions are from North Carolina Environmental Management Commission(EMC)SOC WQ S17-009.
2B-15A NCAC 02L.0202 Standard
CCR-Coal Combustion Residuals
mg/L-milligrams per liter
NA-Not applicable
NPDES-National Pollutant Discharge Elimination System
S.U. -Standard Units
Page 1,of 1

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
APPENDIX A
PHOTOGRAPHS

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
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S-1 View of dispositioned seep location S-1 facing southwest.
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t' .` ••7 e ,• > ,''.g:,.. ? ��w. • ,, » ice a.� . •w�A-."p 4"..... ` ,a*„,„,_*,,,,
om '" •
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i
S-2 View of seep location S-2 facing south.
Page 1 of 5

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas, LLC SynTerra
Ap 41111.11116
. .
S-3 View of seep location S-3 from Lake Wylie facing west.
}
S-4 View of seep location S-4 facing east towards Lake Wylie.
n.
Page 2 of 5

2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
A.
141 i.4 \:'.
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S-5 View of seep location S-5 from Lake Wylie facing west.
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.. .:. "°�,+: a p.
ac.
S-( View of seep location S-6 from Lake Wylie facing west.
Page 3 of 5

• 2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
" i ai i 11" 6
i 4,
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, ',..:: 'mei , . .. , -. 46. —,, ,.s
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S-7 View of seep location S-7 from Lake Wylie facing west.
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S-8 View of seep location S-8 from Lake Wylie facing west.
Page 4 of 5

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• 2019 Annual Seep Report April 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
i
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S-8B View of seep location S-8B from Lake Wylie facing
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View of dispositioned seep location S-09 from Lake Wylie facing
S-9 west.
Assimmemmor- -v.
Page 5 of 5