NC0004979_Other Correspondence_20190424 (2)

DUKE
James
ENERGY®
Vice Presidelnt
Environmental, Health and Safety
Programs & Environmental Sciences
526 South Church Street
Mail Code EC13K
Charlotte, NC 28202
[phone]
April 24, 2019
bd
Via Overnight Mail
„e
M0I-jP-E VII_t,-.REGOraALOF IC
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
ter l� rt e1 mm `yPreg
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 Q1 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
April 24, 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.
James ells
Vice Pr ident, 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

Erin N. Ki fey, EIT
Project E neer
Chrf Suttell, NC LG #2426
Project Manager

2018 Annual Seep Report April 2019
Allen Steam Station, Duke Energy Carolinas, LLC SynTerra
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
- L-IST OF FIGURES
Figure 1 SOC Locations and Inspection Areas
Table 1 SOC Locations and Descriptions-2018 Inspection
LIST OF APPENDICES
Appendix A Photographs
Page

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

2018 Annual Seep Report April 2019
Allen Steam Station, Duke Energy Carolinas, LLC SynTerra
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 #517-009. 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 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
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):
e as am, e weep e oa i e an zTire�7-�s asiri ����
• 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
2.1 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 SWO13-1 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.
0
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
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

LEGEND
NPDES CONSTRUCTED SEEPS
(APPROXIMATE)
C SOC NON -CONSTRUCTED SEEP
(APPROXIMATE)
-
® AOW NOT INCLUDED IN SOC/NPDES
(APPROXIMATE)
--_
SEEP DISPOSITIONED BY SOC
(APPROXIMATE)
__---� ACTIVE ASH BASIN WASTE BOUNDARY
ACTIVEASH BASIN COMPLIANCE
n
BOUNDARY
RETIRED ASH BASIN WASTE BOUNDARY
RETIRED ASH BASIN ASH LANDFILL
WASTE BOUNDARY
RETIREDASH BASIN ASH LANDFILL
-
s
® COMPLIANCE BOUNDARY
-
- -- DORIS FILLS BOUNDARIES
DUKE ENERGY CAROLINAS ALLEN PLANT
BOUNDARY
- -- SPECIAL ORDER BY CONSENT (SOC)
e "- INSPECTIONAREA
_ -
-'
-D--- STREAM (AM EC NRTR 2015)
' WETLAND (AMEC NRTR 2015)
NOTES:
SPECIALORDER BY CONSEWRFOC) LOCATIONS ARE DESCRIBED U
EMC SOC—St IT.
- -
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (TIM )
LOCATIONS AR E DESCRIBED IN PERM IT NC0004979.
_
THE STREAMS AND WETLANDS JURISDICTIONAL OETERI.IINATION
WAS PERFORMED BY TAYLOR WISEMAN AND TAYLOR M`H AND
ASSIGNED —00189. THESE WETLANDS AND
USAGE #SAW
STREAMS WERE APPROVED BY THE US ARMY CORPS OF
ENGINEERS ON MAY 16 2016.
Terra
(USAGE)
AERIAL PHOTOGRAPHY OBTAINED FROM GOGGLE EARTH PRO ON
DECEMBER 13.201E AERIAL WAS COLLECTED ON MARCH IS HNII
f� DUKE
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA
ENERGY
STATE PLANE COORDINATE SYSTEM FIRS 3200 MAD63).
FIGURE 1
3l5 GRAPH ICSCALE INTFEET T50 SOC LOCATIONS AND INSPECTION AREAS
148 RIVER STREET. SURE 220
GREENVILLESOUTNCAROLINA29601 ALLEN STEAM STATION
P DUKE ENERGY CAROLINAS, LLC
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2018 Annual Seep Report April 2019
Allen Steam Station, Duke Energy Progress, LLC SynTerra

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