NC0004961_Notice of Modification_20140314

A
ipA
A��
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Resources
Water Quality Programs
Pat McCrory Thomas A. Reeder
Governor Director
March 14, 2014
CERTIFIED MAIL 70101060 0000 3059 5960
RETURN RECEIPT REQUESTED
John Velte, Environmental Manager
Duke Energy
526 South Church Street
Charlotte, NC 28202
Subject: Notice of Modification Pursuant to 15A NCAC 2H.01 14
Duke Energy — Riverbend Steam Station NC0004961
Gaston County
Dear Mr. Velte
John E. Skvarla, III
Secretary
This letter is to notify you that I have determined that your NPDES Permit for the Riverbend Steam
Station NC0004961 must be reopened. The Division of Water Resources is hereby giving Duke Energy
Carolinas 60 days notice as required by North Carolina Administrative Code (NCAC) 15A 2H .0112
(b)(3) that the Division will reopen the existing permit for the above referenced facility. It is
anticipated that a modified permit will include additional terms and conditions sufficient to ensure the
elimination of any unauthorized discharges.
If you have any questions about this letter, please contact Jeff Poupart at [phone], or via e-mail
at [e-mail].
1-1
Sincere]
i
Thomas
cc: EPA Region IV, Mark Nufher
NPDES Permit File
Central Files
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location 512 N Salisbury St Raleigh, North Carolina 27604
Phone [phone] FAX [phone]
Internet www ncwaterquality org
An Equal Opportunity 1 Affirmative Action Employer

i V
A7A. FILE
CCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Charles Wakild, P.E. Dee Freeman
Governor Director Secretary
March 16, 2012
Attn: Ed Sullivan and Allen Stowe
Water Management
Duke Energy Corporation
EC 13K / Post Office Box 1006
Charlotte, NC 28201-1006
RE: Additional Assessment of Groundwater
Allen, Buck, Marshall & Riverbend Stations
Dear Mr. Sullivan and Mr. Stowe:
We appreciate your meeting with staff of the Mooresville Regional Office of the Division of
Water Quality's Aquifer Protection Section (APS) on March 2nd to discuss groundwater monitoring
efforts at the subject facilities in the Mooresville Region.
To summarize the meeting, APS has requested that Duke begin additional assessment
activities at each of the stations where measured and modeled concentrations of groundwater
constituents exceed 2L groundwater quality standards at the compliance boundary.
Additional assessment activities may be specific to issues at certain wells and include, but
are not limited to: statistical evaluation of constituents that may be naturally occurring, refining
groundwater models for Riverbend and Allen to better describe the flow systems, continued well
development and evaluation of well location and construction, and the assessment of horizontal and
vertical extent of constituents in excess of standards.
We appreciate your cooperation and willingness to continue assessment and will look forward
to a plan outlining a timeline for these activities. Feel free to contact me at [phone] or via
email at Andrew. Pitner(aDncdenr.gov should you have any questions.
Sinc ely,
Andrew H. Pitner, P.G
Regional Aquifer Protection Supervisor
Cc: APS Raleigh (Debra Watts by email)
SWPS Raleigh (Sergei Chernikov by email)
William Miller, Altamont Environmental (by email)
Division of Water Quality I Aquifer Protection Section I Mooresville Regional Office
ne
610 East Center Avenue, Suite 301, Mooresville, North Carolina 28115 Ndf Cat'ohna
Phone. iO4�63-16991 Fax [phone] ��tu��
Internet: www ncwaterqualq.org llff
An Equal OpportumlylAffumahveAchon Employer

Riverbend SW -001 Non Storm Event Sampling Results
Parameter
Result
Units
COD
< 20
mg/I
Chloride
086
mg/I
Fluoride
100
ug/I
Sulfate
64
mg/I
Oil and Grease
< 5
mg/I
Mercury
< 0.05
ug/I
Aluminum
60
ug/I
Barium
13
ug/I
Boron
< 50
ug/I
Calcium
7.03
mg/I
Hardness
204
mg/I
Magnesium
691
ug/I
Manganese
120
ug/I
Zinc
479
ug/I
Antimony
< 1
ug/I
Arsenic
< 1
ug/I
Cadmium
125
ug/I
Chromium
< 1
ug/I
Copper
15.8
ug/I
Lead
1.99
ug/I
Molybdenum
1.48
ug/I
Nickel
< 1
ug/I
Selenium
18.1
ug/I
Thallium
< 0 2
ug/I
pH
706
Std. Units
Specific Conductance
61.6
us/cm
Temperature
10 7
Celsius
TDS
37
mg/I
TSS
< 5
mg/I

Allen Steam Station
Dissolved oxygen and water temperature measured via a calibrated Hydrolab DataSonde°
at near -surface (0 3 m) and 1 meter depth increments, to within 0 5 meters of the bottom Graphical
techniques were used to asses selected vertical profile data.
(Assessment of Balanced and Indigenous Populations in Lake Wylie near Allen Steam Station, NPDES
Permit No NC0004979, Duke Energy, November 2009)
Riverbend Steam Station
At each sampling location (A, B, C, D, E and G), vertical profiles of in-situ parameters (water
temperature, dissolved oxygen, pH and specific conductance) were collected with a Hydrolab
DataSonde° Readings were taken at near -surface (0 3 m) and 1 meter depth increments, to within 0.5
meters of the bottom Graphical techniques were used to asses selected vertical profile data
Water samples for the following chemical parameters were also collected at the sampling sites
listed above
Total alkalinity
Aluminum
Total Recoverable Arsenic
Barium
Total recoverable Cadmium
Calcium
Total Organic Nitrogen
Chloride
Total Recoverable Chromium
Dissolved Copper
Total Recoverable Copper
Total Recoverable Iron
Total Recoverable Lead
Magnesium
Manganese
Ammonia Nitrogen
Nitrate + Nitrate Nitrogen
Total Kjeldahl Nitrogen
Nickel
Orthophosphate Phosphorus
Total Phosphorus
Potassium
Selenium
Sediment Selenium
Silica (as Si)
Silver
Sodium
Total Solids
Total Suspended Solids
Sulfate
Turbidity
Zinc
Water samples were collected with a Kemmerer bottle at the surface (0.3 m) at each location and
approximately one meter above the bottom at the MIHS forebay (Location G). Sediment cores were
collected at four locations (A, B, C and G).
(Assessment of Balanced and Indigenous Populations in Mountain Island Lake near Riverbend Steam
Station, NPDES Permit No NC0004961, Duke Energy, August 2009)
Marshall Steam Station
In conjunction with macroinvertebrate sampling, a calibrated Hach° HQ40d water quality meter was used
to measure dissolved oxygen meter was used to measure water temperature and dissolved oxygen
above the sediment at each location.
((Assessment of Balanced and Indigenous Populations in Lake Norman near Marshall Steam Station,
NPDES Permit No NC0004987, Duke Energy, October 2009)

r
MW -15
S-4• '
�MW-3S
S-9 MW -3D`
S-5•
MW-11SR .
* MW -25
/MW -2D
�%' cqT
A,QT'9iy e,9
l�Ao�F� %LFA
\MW -4S 'YQ 4'o O
MW -4D 646 �2�'FF
` a V1�13
MW -SS
e MW -5D
S-10
ASH BASIN S-11* MW -6S
SECONDARY CELL ♦ MW 6D
QJJ OS 3� / S-12
MW -10 / ASH BASINMW 14�
� � O
J;� Pp O� ``` %NPDES 002 S-8
S-7
MW -1S
\ MW -1D
S-2 ASH BASIN i
1 ` • S-1 PRIMARY CELL
278.0 NPDES 002A A MW -9 f `!
/
CINDER STORAGE
- -- f i
IQ ASH STORAGE '
_ — MW -81
MW -81)
RIVER BEND
STEAM STATION
A
NPDES /ArN 1
NOTES:
1. PARCEL DATA FOR THE SITE WAS OBTAINED FROM DUKE ENERGY REAL ESTATE AND IS APPROXIMATE.
2. TOPOGRAPHY DATA PROVIDED BY DUKE ENERGY.
3. WASTE BOUNDARY IS APPROXIMATE.
4. GROUNDWATER MONITORING WELL LOCATIONS PROVIDED BY DUKE ENERGY.
5. SEEP SAMPLING LOCATIONS WERE OBTAINED BY HDR USING A TRIMBLE HANDHELD GPS UNIT ON APRIL 29, 2014.
6. WATER QUALITY AND NPDES SAMPLE LOCATIONS WERE PROVIDED BY DUKE ENERGY AND ARE APPROXIMATE.
7. NPDES OUTFALL LOCATIONS WERE PROVIDED BY DUKE ENERGY AND ARE APPROXIMATE.
B. S-10 NOT SAMPLED DUE TO INSUFFICIENT FLOW.
9.' INDICATES SEEP SAMPLING LOCATIONS WERE NOT RECORDED WITH GPS UNIT AND ARE APPROXIMATE.
SCALE (FEET)
300' 0 300' 600'
l" = 600'
,/ \\
MW-7SR
MW -7D
(BACKGROUND)
HDR Enpineennp, Inc.
. m. c..on�..
.w sewn Ch— w... coal- nc 21202
1
S-8 •
277.5 v
NPDES 002 A
O
0
IE
277.5
LEGEND:
DUKE ENERGY PROPERTY BOUNDARY
WASTE BOUNDARY
MOUNTAIN ISLAND LAKE BOUNDARY
SEEP SAMPLE LOCATION
WATER QUALITY SAMPLE LOCATION
NPDES OUTFALL LOCATION
COMPLIANCE GROUNDWATER MONITORING WELL
VOLUNTARY GROUNDWATER MONITORING WELL
IDENTIFIED SEEPS AND WATER QUALITY
SAMPLE LOCATION MAP
RIVERBEND STEAM STATION ASH BASIN
DUKE ENERGY CAROLINAS, LLC
GASTON COUNTY, NC
DATE
MAY 15, 2014
FIGURE
1