NC0004979_Report_20190424 (2)

L % t DUKE James Wells
ENERGY Vice President
Environmental, Health and Safety
Programs&Environmental Sciences
526 South Church Street
Mail Code EC13K
Charlotte,NC 28202
[phone]
April 24, 2019
Via Overnight Mail
RegionalCorey Basinger Office Regional Supervisor REC�t1✓EaDEN'io
Mooresville
g P R
North Carolina Department of Environmental Quality APR 29 2019
Division of Water Resources tearer
Water Resources - Water Quality Regional Operations Pan»ft, S rces
610 East Center Avenue, Suite 301 n
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
2018 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 and to begin
addressing decanting impacts on the seeps as required by the Allen Steam Station NPDES Permit
NC0004979 Special Order by Consent (SOC), SOC No. S 17-009 Section 2.c.3).
The attached report was for events conducted during 2018 following issuance of the SOC.
During QI 2019 and as reported to Mr. Sledge on April 3, 2019, an additional seep has been
identified near the Active Ash Basin Cell 1 seep collection system, designated as S-10, due to a
pumping system malfunction. Duke Energy requests coverage in the SOC of system
malfunctions at S-10 and the resulting seepage noted as a new identified seep, S-12. Seepage
from this area drains to a stormwater drainage ditch, discharging to the Catawba River and is
monitored via the Allen SOC upstream and downstream quarterly sampling events. For clarity,
Duke Energy will continue to pump this system back to the ash basin in accordance with the

Messrs. Basinger and Sledge
April24, 2019
Page 2
design of the pumping system. Coverage is sought for non-routine instances where the system
may experience a malfunction.
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.
Please direct any questions concerning the Allen Steam Station NPDES Permit NC0004979 SOC
No. S 17-009 to Elizabeth Glenn at [phone] and to Chris Hallman at [phone]
relative to the annual seep inspection report.
Sincerely,
James Wells
Vice Prsident, Environment, Health& Safety-
Programs and Environmental Sciences
Duke Energy
Attachment:
Allen Steam Station 2018 Annual Seep Survey
CC: Richard Baker, Duke Energy
Elizabeth Glenn, Duke Energy
Chris Hallman, Duke Energy
Randy Gantt, Duke Energy
Paul Draovitch, Duke Energy
Matt Hanchey, Duke Energy

synTerra
2018 ANNUAL SEEP REPORT
ALLEN STEAM STATION
EMC SOC WQ S17-009
235 PLANT ALLEN ROAD
BELMONT, NC 28012
APRIL 2019 0 9
PREPARED FOR
DUKE ENERGY CAROLINAS, LLC
ts DUKE
ENERGY
CAROLINAS
44(_,
Erin N. Ki ey, EIT
Project Engineer
Chr% Suttell, NC LG #2426
Project Manager

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
TABLE OF CONTENTS
SECTION PAGE
1.0 INTRODUCTION 1
2.0 FINDINGS 3
2.1 General Observations 3
2.2 Impact of Decanting 3
2.3 Changes to Seep Status 3
3.0 REFERENCES 4
LIST OF FIGURES
Figure 1 SOC Locations and Inspection Areas
LIST OF TABLES
Table 1 SOC Locations and Descriptions-2018 Inspection
LIST OF APPENDICES
Appendix A Photographs
Page i

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
LIST OF ACRONYMS
AOW Areas of Wetness
CCR Coal Combustion Residuals
EMC Environmental Management Commission
SOC Special Order by Consent
Page ii

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
1.0 INTRODUCTION
On June 6, 2018, Chris Suttell (NC L.G. #2426) of SynTerra inspected the Allen Steam
Station(Allen or Site)for existing and potential new areas of wetness (AOWs). The
aforementioned activities were performed in accordance with North Carolina Special
Order by Consent EMC WQ#S17-009. That Special Order by Consent(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 identificationof 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.
General inspection observations include:
• No previously unidentified seeps were observed during the inspection.
• No notable changes to seep status were observed during this inspection.
• Decanting had not begun at the time of this inspection.
Page 1

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
Inspection Details
Weather during and preceding the inspection was clear. Temperatures ranged from
approximately 65 to 88 degrees F. No significant rain (>0.1 inch) occurred in the three
days before the inspection according to the onsite rain gage.
The inspector reviewed previous AOW inspection reports and the weekly dam safety
inspection reports for each ash basin. Scott Harris (Duke Energy system owner)
conducted the ash basin dam safety inspections and prepared the reports. Mr. Harris,
Ms. Mary Parlemon (Duke Energy CCP Field Support) and Mr. Chris Hallman (Duke
Energy Subject Matter Expert) were interviewed concerning recent rainfall amounts,
recent construction/stabilization projects associated with the ash basins, and general site
conditions in and around the ash basins. Observations from the dam safety inspection
reports were consistent with observations made during the SOC inspections.
The inspection included observations in 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
The inspection scope of work included a review of the areas identified as downgradient
of the ash basin. SOC locations are shown on Figure 1. Observations noted during the
inspection are summarized on Table 1 and discussed in Section 2.Photographs of each
seep location are included in Appendix A.
Page 2

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
2.0 FINDINGS
2.1 General Observations
Inspection observations are shown for each seep in Table 1. Details include:
• Flow at S-02 was noticeably greater than observed during previous AOW
inspections and likely caused by water draining from a designated wetland
upgradient. Flow continued overland toward Lake Wylie.
• Potential flow was submerged in areas where flow had been observed during
previous inspections,notably at S-05, S-06, and S-07.
• No flow was observed from stormwater pipes designated SW013-1 through
SW013-13.
2.2 Impact of Decanting
Decanting of the ash basin at Allen had not yet begun at the time of this inspection.
2.3 Changes to Seep Status
Mr. Suttell inspected each seep to evaluate whether it may 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.
Seeps dispositioned during 2018 were done so at the time of the SOC issuance. Table 1
lists those seeps dispositioned and the basis for disposition. Seeps identified as
dispositioned at Allen are S-01 and S-09 These dispositioned seeps will continue to be
inspected and evaluated for any change in flow conditons.
In general, there was no change in status of the dispositioned seeps and no change in
status of remaining seeps observed during this inspection.
Page 3

2018 Annual Seep Report April 2019
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 4

•
2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Progress,LLC SynTerra
FIGURE

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NATIONAL POLLUTANT DISCHARGE EUMINI,TION SYSTEM INPOESI
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THE STREAMS AND WETLANDS JURISDICTIONAL DETERMINATION
WAS PERFORMED RY TAYLOR WISEMAN AND TAYLOR(TWT)ANO `, En====1 FIGURE 1
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REAMS WERE APPROVED BY THE US ARMY CORPS OF SOC LOCATIONS AND INSPECTION AREAS
ENGINEERS IUS.CEI CAI M.Y162018 SyIITerra GREENVILLE.SOUTH CAROLINA 2S601 ALLEN STEAM STATION
AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON PHONE S60,219999
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TABLE 1
SOC LOCATIONS AND DESCRIPTIONS-2018 INSPECTION
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
Latitude Longitude Waterbody classification
Allen S-Ol" 35.170632 -81.010093 Catawba River WS-V;B Located south of active ash basin.Flow Is in approximately 3 foot wide NA-Seep Dispositloned NA-Seep Dlsposltlonetl Stream flowing at a trickle.Water emerges from face of the
(Lake Wylie) channel flowing southeast to Lake Wylie.Via sampling-No CCR Impacts bank at a steady trickle.
Dry channel.Orange aerobic bacteria/floc/Iron-oxidation
Allen 5-02 35.173761 -81.00578 Catawba River WS-V;B Located south of active ash basin at toe of dike.Flows to approximately 3 Monitoring at point prior to pH 5-10 S.U. apparent on substrate.Wetness observed 50 yards upgradient
(Lake Wylie) foot wide channel that flows to Lake Wylie entering Lake Wylie Hardness 400 mg/L of sign that Infiltrates along channel before AOW sign with no
apparent re-emergence.
Moderate and steady flow that emerges from low areas at the
Catawba River Located east of active ash basin,between dike and over bank. Instream Monitoring of east toe of the active ash basin that Is captured by a toe drain
Allen 5-05 35,17698 -81.006087 (Lake Wylie) WS-V'B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-28 Standards Apply system(rip rap blanket)and channeled toward Lake Wylie.No
apparent discoloration of water or substrate.
Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of Steady flow.
Allen 5-06 35.177049 -81.006128 (Lake Wylie) WS-v;B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-28 Standards Apply No apparent discoloration of water or substrate.
Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of Slow steady flow observed From boa[.
Allen 5-07 35.177736 -81.006334 (Lake Wylie) WS-V;a Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-2B Standards Apply From land,no flowing water Is apparent.
No apparent discoloration of water or substrate.
Allen S-09"" 35.185838 -81.00585 Catawba River WS-V;B Former seep with flow through 24"corrugated metal pipe.Pipe has been NA-Seep Dispositloned NA-Seep Dispositinned Not Inspected,dispositioned.
(Lake Wylie) grouted;discharge eliminated.
Moderate and steady flow that emerges from low areas at the
Toe Drain Outfall Catawba River NA-Monitored per terms of east toe of the active ash basin that is captured by a toe drain
Allen 103(5-03) 35.1752 -81.006 (Lake Wylie) WS-V;B Constructed toe drain. the NPDES permit NA-28 Standards Apply system(rip rap blanket)and channeled toward Lake Wylie.
Slight Iron-oxidizing bacteria on substrate and biofilm on
headwaters and within stream.
Moderate and steady flow that emerges from low areas at the
east toe of the active ash basin that Is captured by a toe drain
Toe Drain Outran Catawba River NA-Monitored per terms of system(rip rap blanket)and channeled toward Lake Wylie.
All 104(S-04) 35.17569 -81.00606 (Lake Wylie) VJS-v;B Constructed toe drain. Me NPDES permit NA-28 Standards Apply Water Is generally clear but has some bloflim on the water
surface and orange iron-oxidizing bacteria observed on
substrate.
Toe Drain Outfall Catawba River NA-Monitored per terms of Flow that emerges from low areas at the east toe of the active
Allen 108(5-08) 35.1785 -81.0064 (Lake Wylie) WS-V;B Constructed toe drain. the NPDES permit NA-2B Standards Apply ash basin that is captured within a 12-Inch metal culvert
draining toward Lake Wylie.
Toe Drain Outfall Catawba River NA-Monitored per terms of Flow that emerges from low areas at the east toe of the active
Allen 10BB(5-08B) 35.17816 -81.006517 (Lake Wylie) WS-V;B Constructed toe drain. the NPDES permit NA-2B Standards Apply ash basin toward a culvert directed away from dike toward Lake
Wylie.
Prepared by:SUE Checked by:OIL
Notes:
Location previously Investigated as a seep.Monitoring has not I,dicated the presence of coal combustion residuals.
rra-Seep dispositioned via repair aim/or non-flowing condition to potentially reach Waters of the U.S.,or other,as noted.Monitoring anal 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 ibis Order.
2B-15A NUC 02L.0202 Standard
CCR-Coal Combustion Residuals
mg/L-mailgrams per liter
NA-Not applicable
NPDES-National Pollutant Olscharge System
S.U.-Standard Units
SOC-Special Order by Consent
SOC Tabks_Al1.FIeaL201g_00_17 Page I of 1

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Progress,LLC
SynTerra
APPENDIX A
PHOTOGRAPHS

2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
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S-02 I View of the SOC sample location facing west.
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2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
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S-06 View of seep location facing east,looking towards Lake Wylie.
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SynTerra
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2018 Annual Seep Report April 2019
Allen Steam Station,Duke Energy Carolinas,LLC SynTerra
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S-07 I View of seep location facing east-northeast,towards lake Wylie
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S-09 I View of dispositioned seep S-09 facing west.
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synTerra