HomeMy WebLinkAboutNC0004979_Final Seep Report_20200828 DUKE James Wells
ENERGY: Vice Preside
Environmental,Health and Safe
Programs&Environmental Sciences
526 South Church Street
Charlotte,NC 28202
(980)373-9646
August 28, 2020
Via Overnight Mail
RECEIVED
S. Daniel Smith
Director of Water Resources SEP 01 2020
North Carolina Department of Environmental Quality NCDEQ/DWR/NPDES
1617 Mail Service Center
Raleigh,NC 27699-1617
Bob Sledge
North Carolina Department of Environmental Quality
Division of Water Resources
Water Quality Permitting Program
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
Final Seep Report
Dear Messrs. Smith and Sledge:
On behalf of Duke Energy Carolinas, LLC (DEC), I am submitting to you the Allen Steam Station
Final Seep Report summarizing the findings of the comprehensive survey completed following
completion of decanting as required by the Allen Steam Station NPDES Permit NC0004979
Special Order by Consent (SOC), SOC No. S17-009 Section 2.c.4). Completion of decanting
occurred at Allen on June 2, 2020.
Please direct any questions concerning the Allen Steam Station NPDES Permit NC0004979 SOC
No. S 17-009 to Elizabeth Glenn at(980) 373-0530 and to Chris Hallman at(980) 373-7892
regarding this Final Seep Report.
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
Messrs. Smith and Sledge
August 28, 2020
Page 2
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.
Sincerely,
1104241;6 -
\.
James Wells
Vice President, Environment, Health& Safety-
Programs and Environmental Sciences
Duke Energy
Attachment:
Allen Steam Station 2020 Final Seep Report
CC: Richard Baker, Duke Energy
Elizabeth Glenn, Duke Energy
Shannon Langley, Duke Energy
Chris Hallman, Duke Energy
Randy Gantt, Duke Energy
Paul Draovitch, Duke Energy
Matt Hanchey, Duke Energy
RECEIVED
5 ')fri1TEE 'rr1
SEP 01 2020
NCDEQ/DWR/NPDES
2020 FINAL SEEP REPORT
ALLEN STEAM STATION
EMC SOC WQ S17-009
253 PLANT ALLEN ROAD
BELMONT, NC 28012
AUGUST 2020
PREPARED FOR
tio) DUKE
ENERGY
AROINAS
DUKE ENERGY CAROLINAS, LLC
Leonard W. Drago
Staff Scientist
Ch ' ophJ. Suttell, NC LG #2426
Project Principal
2020 Final Seep Report August 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 Seep Locations and Inspection Areas
LIST OF TABLES
Table 1 Seep Locations and Descriptions—June 2020 Inspection
LIST OF APPENDICES
Appendix A Photographs
Page i
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
1.0 INTRODUCTION
On June 4, 2020, Chris Suttell (NC L.G. #2426) of SynTerra inspected the Allen Steam
Station (Allen or Site) property for existing and potential new seeps. 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:
No later than 90 days following the completion of decanting at each Facility, and
in the same manner as in the annual surveys, Duke Energy shall conduct a
comprehensive survey 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 this survey, including a section analyzing the effect
decanting of the basins(s) has had on seep flows, accompanied by copies of the
photographs noted above, shall be submitted to the Director of DWR ("Final Seep
Report"). This Final Seep Report must list any seep that has been dispositioned
(as described in subparagraph (3) above) during decanting process, including an
analysis of the manner of disposition. The determination of whether a seep is
dispositioned rests with the Director of DWR. At, or at any time prior to,
submission of the Final Seep Report, Duke Energy shall seek formal certification
from the Director of DWR, certifying the disposition of any seep that Duke
Energy has characterized as dispositioned. Any seeps not certified as dispositioned
by the Director of DWR shall not be deemed as dispositioned.
Each location documented as a seep in the current version of the SOC, updated in May
2019, and listed in Table 1, was observed and documented with photographs during
the inspection. General inspection observations include:
• No previously unidentified seeps or pipes were observed during the inspection.
• Notable shoreline erosion was observed.
1.1 Inspection Details
During the inspection, the weather was clear and no precipitation occurred. The most
recent rain event was 0.12 inches on May 30, 2020, as indicated by data from the on-Site
rain gauge. Temperatures during the inspection ranged from approximately 70 to 90
degrees Fahrenheit (F).
Page 1-1
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
The inspector reviewed previous seep inspection reports and the weekly dam safety
inspectionreports pertainingeach p to ash basin. Mr. Scott Harris (Duke Energy system
owner) conducted the ash basin dam safety inspections and prepared the reports. Mr.
Harris and Mr. Chris Hallman (Duke Energy Subject Matter Expert) were interviewed
about recent rainfall amounts, 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 seep inspection.
The inspection included the following areas (Figure 1):
• The east dam,between the coal pile and the retired ash basin (RAB)
• The north dike,between the RAB and the active ash basin (AAB)
• The east dam,between Lake Wylie and the RAB
• The east dam,between Lake Wylie and the AAB
• South and southeast of the AAB, 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
2020 Final Seep Report August 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 previously unidentified seeps or pipes were observed during the inspection.
• Conditions were similar to those reported in recent Dam Safety Inspection
Reports.
• While notable, shoreline erosion was less than observed during the previous
inspection in February 2019.
2.2 Effects of Decanting
Wastewater inflows to the AAB ceased on February 9, 2019. Decanting of free water
from the active ash basin began on June 5, 2019. Duke Energy provided a Notification
for Completion of Decanting letter to the North Carolina Department of Environmental
Quality (NCDEQ) Division of Water Resources (DWR) on July 9, 2020. The notification
indicated that decanting of the AAB was completed on June 2, 2020.
The final seep inspection occurred two days after the completion of decanting,
approximately one year after decanting began.
Decanting of the AAB has reduced seep flow southeast of the AAB where conditions
were dry at S-2 and between S-2 and S-1. No apparent flow was observed at S-2, S-5, S-
6, S-7, and S-9. No surficial flow was observed at S-10 and S-12. The S-10 seep collection
system appeared functional. Minimal flow,which dissipated prior to reaching Lake
Wylie, was observed at National Pollutant Discharge System (NPDES) Outfall 108 (S-8)
and no apparent flow was observed at NPDES Outfall 108B (S-8B). Flow rates at NPDES
Outfalls 103 (S-3) and 104 (S-4) appeared similar to rates observed during previous
inspections.
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 such that concentrations of all pollutants listed in Attachment B meet State
Page 2-1
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
criteria for four consecutive sampling events with at least seven days separating
each event; 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.
Seeps S-2, S-5, S-6, S-7, S-8, and S-8B have been observed as dry or not reaching waters
of the State or Waters of the United States for three consecutive quarters. These seeps
are candidates for dispositioning and Duke Energy requests the NCDEQ review and
certify that they be dispositioned in accordance with the terms of the SOC.
Page 2-2
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
3.0 REFERENCES
Duke Energy Carolinas, LLC. (July 9, 2020).Allen Steam Station, Special Order by Consent,
EMC SOC WQ S17-009, Notification for Completion of Decanting.
Environmental ali 2018 . S ecial Order Consent
North Carolina Department ofQuality.t3' ( ) P by
EMC SOC WQ S17-009.
North Carolina Department of Environmental Quality. (2018). Issuance of NPDES Permit,
Permit NC0004979,Allen Steam Station, Gaston County, Facility Class I.
Page 3-1
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
FIGURES
•
+1164 r
•
11
010,
II
r' - .. .._I . ATAWBA RIVER . -
f,A, • (LAKE WYLIE)
I
s r
—
„. .01.11104 ........ •: ,, . •,,i.:---- - ...;," ,... .. '. - ,,.. . .
•
J
x � .1
y�
'Y\y D/SCHgRGE CANA, ',, ;
,`.
' -.5, ,...461,, jai''.
•
)I ',.,_ . ' ... . , ,..' -'. iir,' , 0-ir
-'f' a •
v,
a-4
-
• .: .
r'"�� RETIRED
'—.1 - I ASH BASIN
'' ,
R
1
I
•....'1 /
1
r
•
r T 4 1 I Toe Drain
}F°"`''°Pu .} _ e a" . Outfall108
PnNs , '7.x .. !/(S-8)
F'•� - d Y ..
s ' II Toe Drain
_r—---I J,' -rt: - Outfall 1088
r:'
I El
a j " ACTIVE �'e,;S-6
- a@ ASH BASIN •
q
F .
D
. ._ r.
, Toe Drain
_ Outfall 104
'.= IS 4)
Toe Drain
LEGEND jOutfall103
i NPDES CONSTRUCTED SEEP I (S-3)
.
• SOC NON-CONSTRUCTED SEEP
• SEEP DISPOSITIONED BY SOC ;
-ACTIVE ASH BASIN WASTE BOUNDARY 1 .. � •
---RETIRED ASH BASIN WASTE BOUNDARY 1*- I'
......•DUKE ENERGY CAROLINAS PROPERTY LINE I .
1223 SPECIAL ORDER BY CONSENT(SOC) .1
INSPECTION AREA ,
----)0--STREAM(AMEC NRTR 2015) ' ��.- CATAWBA RIVE
WETLAND(AMEC NRTR 2015) •, 7
- *SURFACE WATER FLOW DIRECTION ' '� '
V.
NOTES: t_ _^
_ 1 I
1.SEEP LOCATIONS ARE DESCRIBED IN EMC SOC WO S17-009. . -- ` /1
2.NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM(NPDES, • •-
LOCATIONS ARE DESCRIBED IN PERMIT NC0004979 M r .I t'
;
3 SEEP LOCATIONS WERE DERIVED FROM VARIOUS SOURCES AND F:- ill:, - ��
A MIX OF SURVEYED AND APPROXIMATE LOCATIONS.THEREFORE.Si-. •
LOCATIONS ARE TO BE DEEMED APPROXIMATE. 1! r -
4 THE WATERS OF THE U S DELINEATION HAS NOT BEEN APPROVED
THE U.S.ARMY CORPS OF ENGINEERS AT THE TIME OF THE MAP �
CREATION.THIS MAP IS NOT TO BE USED FOR JURISDICTIONAL "'�Y.tG • C•
DETERMINATION PURPOSES.THE WETLANDS AND STREAMS .tP ...
BOUNDARIES WERE OBTAINED FROM STREAM AND WETLAND "' - "
DELINEATION CONDUCTED BY AMEC FOSTER WHEELER
ENVIRONMENTAL a INFRASTRUCTURE,INC.NATURAL RESOURCE 400 0 400 800
TECHNICAL REPORT(NRTR)FOR ALLEN STEAM STATION DATED MAY 29, DUKE FIGURE 1
2016. V'ENERGY.
GRAPHIC SCALE IN FEET SEEP LOCATIONS AND INSPECTION AREAS
5.PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS. CAROLINAS
6 ALL BOUNDARIES ARE APPROXIMATE. DRAWN BY:K.KING DATE:04/10/2019 2020 FINAL SEEP REPORT
REVISED BY:R.KIEKHAEFER DATE:07/23/2020
7.AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON CHECKED BY:T.HARTMAN DATE:07/23/2020 ALLEN STEAM S TAT I O N
DECEMBER 13,2018.AERIAL WAS COLLECTED ON MARCH 30,2018 APPROVED BY:L.DRAGO DATE:07/23/2020
8.DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA �1��1 PROJECT MANAGER:C.SUTTELL BELMONT, NORTH CAROLINA
STATE PLANE COORDINATE SYSTEM FIPS 3200(NAD83). s r Teri ya
'�J www.svnterracorp.com
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
TABLES
TABLE 1
SEEP LOCATIONS AND DESCRIPTIONS —JUNE 2020 INSPECTION
2020 FINAL SEEP REPORT
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
Location Coordinates Receiving Receiving Facility Seep ID Number Waterbody Waterbody Description*** SOC Monitoring Interim Action Levels Notes from Inspection
Latitude Longitude Classification
Located south of active ash basin. Flow is in approximately 3 foot
•
Allen S-1* 35.170632 -81.010093 Catawba River WS-V; B wide channel flowing southeast to Lake Wylie.Via sampling-No CCR NA-Seep Dispositioned NA-Seep Dispositioned Steady stream flow that emerges from within an a naturally incised channel side-
(Lake Wylie) gradient of the ash basin. No apparent
pparent discoloration of water or substrate.
Catawba River Located south of active ash basin at toe of dike. Flows to Monitoring at point prior to pH 5-10 S.U.
Allen 5 2 35.173761 -81.00578 (Lake Wylie) WS-V; B approximately 3 foot wide channel that flows to Lake Wylie entering Lake Wylie Hardness 400 mg/L No apparent flow.Orange aerobic bacteria/floc/iron-oxidation apparent on substrate.
Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of
Allen S-5 35.17698 -81.006087 (Lake Wylie) WS-V; B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate.
Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of
Allen S-6 35.177049 -81.006128 (Lake Wylie) WS-V; B Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate.
Catawba River Located east of active ash basin,between dike and river bank. Instream Monitoring of
Allen S-7 35.177736 -81.006334 WS-V; B NA-02B Standards Apply No apparent flow. No apparent discoloration of water or substrate.
(Lake Wylie) Intermittent,unconfined diffuse flow towards Lake Wylie. Lake Wylie
Allen S-9** 35.185838 -81.00585 Catawba River(Lake Wylie) WS-V; B Former seep with flow through 24"corrugated metal pipe. Pipe has NA-SeepDispositioned NA-SeepDispositioned Dispositioned. No
y ) been grouted; discharge eliminated. P P p apparent flow.
NA-flow is collected and pumped Located north of active ash basin in grassy area that is dewatered by
Allen 5-10 35.18055 -81.01354 back into NPDES permitted NA a French drain system down gradient ofPond 1. Captured NA Monitoring not
Primary y g NA No a
wastewater system in accordance with required by SOC apparent flow. French drain system and pumping station functioning.
the pumping system's design capacity water is pumped back into the active ash basin.
Overflow discharge of seepage collected from S-10 occurring during
temporary,infrequent power outage episodes.Seepage would flow Instream Monitoring of No apparent flow received from S 10 as the French drain system and pumping
Allen S-12 35.18101 -81.01349 Catawba River(Lake Wylie) WS-V; B to a stormwater drainage channel. Seep flow is collected and Lake Wylie NA-026 Standards Apply station at S-10 was functioning.
pumped back into the ash basin during normal operations.
NPDES Locations
Toe Drain Outfall Moderate and steady flow that emerges from low areas at the east toe of the active
Catawba River NA-Monitored per terms NA-NPDES Permit Effluent ash basin that is captured by a toe drain system (rip rap blanket)and channeled
Allen 103 35.1752 -81.006 Lake Wylie) WS-V; B Constructed toe drain. of the NPDESpermit Limitations Apply toward Lake Wylie. Slight iron-oxidizingbacteria on substrate and biofilm on
(S-3) ( Y ) PP Y Y 9
headwaters and within stream.
Toe Drain Outfall Moderate and steady flow that emerges from low areas at the east toe of the active
Catawba River NA-Monitored per terms NA-NPDES Permit Effluent ash basin that is captured by a toe drain system (rip rap blanket)and channeled
Allen 104 35.17569 -81.00606 WS-V; B Constructed toe drain.
(Lake Wylie) of the NPDES permit Limitations Apply toward Lake Wylie. Water is generally clear but has some biofilm on the water
(S 4) surface and orange iron-oxidizing bacteria observed on substrate.
Toe Drain Outfall Catawba River NA-Monitored per terms NA-NPDES Permit Effluent Flow that emerges from low areas at the east toe of the active ash basin that is
Allen 108 35.1785 -81.0064 Lake Wylie) WS-V; B Constructed toe drain. of the NPDESpermit Limitations Applycaptured within a 12-inch metal culvert. Flow infiltratesprior to reachingLake Wylie.
(S-8) ( Y ) P Y
Toe Drain Outfall Catawba River NA-Monitored terms NA-NPDES Permit Effluent No per
Allen 108E 35.17816 -81.006517 WS-V; B Constructed toe drain. apparent flow. Historically,flow emerged from low areas at the east toe of the
(Lake Wylie) of the NPDES permit Limitations Apply active ash basin toward a culvert directed away from dike toward Lake Wylie.
(S-8B)
Prepared by:BOB Checked by:EEL
Notes: Revised by:LWD Checked by:0J.8
*-Location previously investigated as a seep.Monitoring has not indicated the presence of coal combustion residuals.
**-Seep dispositioned ma repair and/or non-flowing condition to potentially reach Waters of the U.S.,or other,as noted.
***-Some descriptions have been updated from the original text found in the SOC Attachment A table for accuracy and currency.
The information provided in this table,except for the"Notes From Inspection"column,was derived from Special Order by Consent EMC SOC WQ 517-009,Attachment A and NPDES Permit NC0004979.
02B-15A NCAC 02L.0202 Standard
CCR-Coal Combustion Residuals
FERC-Federal Energy Regulatory Commission
mg/L-milligrams per liter
NA-Not applicable
NPDES-National Pollutant Discharge Elimination System
OHWM-Ordinary High Water Mark
S.U.-Standard Units
Page 1 of 1
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
APPENDIX A
PHOT
OGRAPHS
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
t
•
O 167*SE(f) ``rw ' ,
- c• ." .fir
-+, ,�. '
ilit . . ,t.-,- -
- --„-......, .
-.A.,.,. ,,, 4 >.• yam•- 4 ~h► .'I' At -1 ,r, ', " aice V��" h L.lit 9
F,� '
r1wv' ,j unb1020. r>
S-1 View of dispositioned seep location S-1, facing south.
riall111/1111.1
0 142'SE(T)1 35.173806,"t„Of),73 t7m A 1 Q7
ny -vi
.
ICI F
f
• y r-
S-2 View of seep location S-2,facing southeast.
r.
Page 1 of 6
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
E
`anI4
t! r)S 35.175348, 81.006034.5m•1
cJ-3 View of seep location S-3(NPDES Outfall 103),facing northeast towards
Lake Wylie.
NL L
n w
'N (T)i .17 71 :111.1:: . m 14:m
M
•
kk, E III
v
p, ,
View of seep location S-4(NPDES Outfall 104),facing northeast towards i
�-4 Lake Wylie.
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2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
sw w
oo9,$700614twn•1'
- d
•
1
I
S-5 View of seep location S-5 from Lake Wylie,facing southwest.
itetiWtt
t
P
S-6 View of seep location S-6 from Lake Wylie,facing,outh‘\ mot.
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2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
otdi NW
..':1 0062-: m 141 m
Er
.4
S-7 View of seep location S-7 from Lake Wylie,facing northwest.
SE S SW
.m
1731 MP$5.178522,-81.0064,42 Om♦158 m
1i
�`f '•� 44011
to
View of seep location S-8(NPDES Outfa11108)from bank along Lake
S-8 Wylie,facing south.
Page 4 of 6
2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
elsommin111111111.11111111111111111111111111111W- 1
C:=.1`W(1 • ,,1'8254, 81001,39t6m♦138m
3.,1440
It: _ 11441, 41/1gi
a1
y. ti y.
rK''4-
T�A
f l.
S-$B View of seep location S-8B(NPDES Outfa11108B)from bank along Lake
Wylie,facing west-northwest.
SW.
` t SW(T)*35.1`,1, 81005344tam 1
Al - ,
1'
S-9 View of dispositioned seep location S-9 from Lake Wylie,facing west.
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2020 Final Seep Report August 2020
Allen Steam Station-Duke Energy Carolinas,LLC SynTerra
SE S
S-ZQ View of dispositioned seep location S-10,facing southeast.
A 17u
is
S-12 View of seep location S-12,facing north-northeast.
Page 6 of 6