NCS000572_Minor Modification_20200918.pdf

ROB' COOPER
Governor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Director
Terry Tuck
General Manager II
Dan River Combined Cycle
864 South Edgewood Drive
Eden, NC 27288
Dear Mr. Tuck:
NORTH CAROLINA
Environmental Quality
Subject: NPDES Stormwater Permit
Permit No. NCS000572
Minor Modification
Dan River Combined Cycle Station
Rockingham County
The Division of Energy, Mineral, and Land Resources' Stormwater Program received your
request to revise permit no. NCS000572 on July 30, 2020.
The Division has reviewed and approved your request to include Stormwater Outfall
SWO02 in the analytical monitoring requirements for NPDES Permit No. NCS000572.
Additionally, the Division has also approved your request to designate the official sampling
location of SWO02 as the discharge from the culvert on the river side of Edgewood Road,
and the official sampling location of SWO10 as the discharge from the culvert on the
wetland side of the landfill access road.
The changes to this permit are being approved as minor modifications because the
drainage areas of these outfalls are similar to outfall drainage areas that are already
included in this permit. This permit modification will be issued during the semi-annual
stormwater sampling period for the site. If the semi-annual sampling has already occurred
prior to the issuance of the permit modification, then you will only be required to resample
for outfalls SWO02 and SW010.
This modification includes the following changes from your current permit:
• Modifications to the permit in Part II on page on 9 of 17, to designate the sampling
location for SWO02;
North Carolina Department of Environmental Quality I Division of Energy, Mirzer-al and Land Resources
51.2 North Salisbury Street , 1612 Mail Service Center I Raleigh North Carolina 27699-1612
9�';=riiietita Eiiirenrnata�eoz,Itt 919,707.9200

• Modifications to the permit in Part II on page 9 of 17, to include Outfall SW002 in
the analytical monitoring requirements listed in Table 5;
• Modifications to the permit in Part II on page 10 of 17 to designate the sampling
location for SW010;
• Modifications to the permit in Part II on pages 6-10 of 17 to update verbiage that
referred to construction/demolition activities that have now been completed; and
• Revisions to the permit cover page to reflect the latest amendment date.
Please replace Part II, Monitoring, Controls, and Limitations For Permitted
Discharges, in the current permit with the revised Part II and discard the older Part
II.
All other conditions and schedules in the previous permit remain in place and in effect.
If any parts, measurement frequencies, or sampling requirements in this modification are
unacceptable to you, then you have the right to file a petition for a contested case with the
Office of Administrative Hearings within (30) days following the receipt of the letter. This
petition must conform to the requirements of Chapter 150B of the North Carolina General
Statutes. Petitions must be timely filed with the Office of Administrative Hearings, Post
Office Drawer 11666, Raleigh, North Carolina 27604. If you do not file a petition within the
required time, the agency decision shall be final and binding.
If you have and questions or comments concerning this correspondence, contact Annette
Lucas at [phone] or at [e-mail].
Sincerely,
for Brian Wrenn, Director
Division of Energy, Mineral, and Land Resources
cc: Winston-Salem Office, DEMLR Stormwater Program
Sam Sampath, US EPA (via email)
Joyce Dishmon, Duke Energy (via email)
Stormwater Program
Enclosure

Permit No. NCS000572
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL, AND LAND RESOURCES
PERMIT
TO DISCHARGE STORMWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provisions of North Carolina General Statute 143-215.1, other
lawful standards and regulations promulgated and adopted by the North Carolina
Environmental Management Commission, and the Federal Water Pollution Control Act, as
amended,
Duke Energy Carolinas, LLC
is hereby authorized to discharge stormwater from a facility located at:
Dan River Combined Cycle Station
864 South Edgewood Drive
Eden, NC
Rockingham County
to receiving waters designated as Dan River, a class C water in the Roanoke River Basin, in
accordance with the discharge limitations, monitoring requirements, and other conditions
set forth in Parts I, II, III, and IV hereof.
This permit shall become effective October 1, 2015
This permit and the authorization to discharge shall expire at midnight on September 30,
2020.
Originally issued the 1st day of October 2015; amended and signed this 18th day of
September 2020.
vm(uc
for Brian Wrenn, Director
Division of Energy, Mineral and Land Resources
By the Authority of the Environmental Management Commission

Permit No. NCS000572
PART II MONITORING, CONTROLS, AND LIMITATIONS FOR
PERMITTED DISCHARGES
SECTION A: STORMWATER POLLUTION PREVENTION PLAN (SWPPP)
The permittee shall develop and implement a Stormwater Pollution Prevention
Plan (SWPPP). The SWPPP shall be maintained on site unless exempted from this
requirement by the Division. The SWPPP is public information in accordance with
Part III, Standard Conditions, Section E, paragraph 3 ofthis permit. The SWPPP
should also specifically and separately address deconstruction, demolition, coal,
and/or coal ash hauling or disposal activities. The SWPPP shall include, at a
minimum, the following items:
1. Site Overview. The Site Overview shall provide a description of the physical facility
and the potential pollutant sources that may be expected to contribute to
contamination of stormwater discharges. The Site Overview shall contain the following:
(a) Ageneral location map (USGS quadrangle map or appropriately drafted
equivalent map), showing the facility's location in relation to transportation
routes and surface waters; the name of the receiving waters to which the
stormwater outfalls discharge, or if the discharge is to a municipal separate
storm sewer system, the name of the municipality and the ultimate receiving
waters; and accurate latitude and longitude of the points of stormwater
discharge associated with industrial activity. The general location map (or
alternatively the site map) shall identify whether any receiving waters are
impaired (on the state's 303(d) list of impaired waters) or if the site is
located in a watershed for which a TMDL has been established, and what
the parameters of concern are.
(b) A narrative description of storage practices, loading and unloading
activities, outdoor process areas, dust or particulate generating or control
processes, and waste disposal practices. Anarrative description of the
potential pollutants that could be expected to be presentin the stormwater
discharge from each outfall. The narrative should also reference
deconstruction, demolition, coal, and/or coal ash hauling or disposal
activities where applicable.
(c) A site map drawn at a scale sufficient to clearly depict: the site property
boundary; the stormwater discharge outfalls; all on -site and adjacent surface
waters and wetlands; industrial activity areas (including storage of materials,
disposal areas, process areas, loading and unloading areas, and haul roads); site
topography and finished grade; all drainage features and structures; drainage
area boundaries and total contributing area for each outfall; direction of flow in
each drainage area; industrial activities occurring in each drainage area;
buildings; stormwater Best Management Practices (BMPs); and impervious
surfaces. The site map must indicate the percentage of each drainage area that is
Part II Page 1 of 17

Permit No. NCSOOOS72
impervious, and the site map must include a graphic scale indication and north
arrow.
(d) A list of significant spills or leaks of pollutants during the previous three (3) years
and any corrective actions taken to mitigate spill impacts.
(e) Certification that the stormwater outfalls have been evaluated for the presence
of non-stormwater discharges. The permittee shall submit the first
certification no later than 90 days after the effective date of this permit to
the Stormwater Permitting Program Central Office and shall re -certify
annually that the stormwater outfalls have been evaluated for the
presence of non-stormwater discharges. For any non-stormwater discharge
identified, the permittee shall indicate how that discharge is permitted or
otherwise authorized. The certification statement will be signed in accordance
with the requirements found in Part III, Standard Conditions, Section B,
Paragraph 3.
2. Stormwater Management Strategy. The Stormwater Management Strategy
shall contain a narrative description of the materials management practices
employed which control or minimize the stormwater exposure of significant
materials, including structural and nonstructural measures. This strategy
should also address deconstruction, demolition, coal, and/or coal ash hauling or
disposal activities where applicable. The Stormwater Management Strategy, ata
minimum, shall incorporate the following:
(a) Feasibility Study. A review of the technical and economic feasibility of
changing the methods of operations and/or storage practices to
eliminate or reduce exposure of materials and processes to rainfall and
run-on flows. Wherever practical, the permittee shall prevent exposure
of all storage areas, material handling operations, and manufacturing
or fueling operations. In areas where elimination of exposure is not
practical, this review shall document the feasibility of diverting the
stormwater run-on away from areas of potential contamination.
(b) Secondary Containment Requirements and Records. Secondary
containment is required for: bulk storage of liquid materials; storage in
any amount of Section 313 of Title III of the Superfund Amendments
and Reauthorization Act (SARA) water priority chemicals: and storage
in any amount of hazardous substances, in order to prevent leaks and
spills from contaminating stormwater runoff. A table or summary of all
such tanks and stored materials and their associated secondary
containment areas shall be maintained. If the secondary containment
devices are connected to stormwater conveyance systems, the
connection shall be controlled by manually activated valves or other
similar devices which shall be secured closed with a locking
mechanism. Any stormwater that accumulates in the containment area
shall be observed for color, foam, outfall staining, visible sheens and
Part II Page 2 of 17

Permit No. NCS000572
dry weather flow, prior to release of the accumulated stormwater.
Accumulated stormwater shall be released if found to be
uncontaminated by any material. Records documenting the individual
making the observation, the description of the accumulated
stormwater, and the date and time of the release shall be kept for a
period of five (5) years. For facilities subject to a federal oil Spill
Prevention, Control, and Countermeasure Plan (SPCC), any portion of
the SPCC Plan fully compliant with the requirements of this permit
may be used to demonstrate compliance with this permit. In addition
to secondary containment fortankage, the permittee shall provide
drip pans or other similar protection measures for truck or rail car
liquid loading and unloading stations.
(c) BMP Summary. A listing of site structural and non-structural Best
Management Practices (BMPs) shall be provided. The installation and
implementation of BMPs shall be based on the assessment of the
potential for sources to contribute significant quantities of pollutants
to stormwater discharges and on data collected through monitoring of
stormwater discharges. The BMP Summary shall include a written
record of the specific rationale for installation and implementation of
the selected site BMPs. The BMP Summary should also address
deconstruction, demolition, coal, and/or coal ash hauling or disposal
activities where applicable. The permittee shall refer to the BMPs
described in EPA's Multi -Sector Permit (MSGP) and Industrial
Stormwater Fact Sheet for Steam Electric Power Generating Facilities
(EPA-833-F-06-030) for guidance on BMPs that may be appropriate for
this site. The BMP Summary shall be reviewed and updated annually.
3. Spill Prevention and Response Procedures. The Spill Prevention and
Response Procedures (SPRP) shall incorporate an assessment of potential
pollutant sources based on a materials inventory of the facility. Facility
personnel responsible for implementing the SPRP shall be identified in a
written list incorporated into the SPRP and signed and dated by each
individual acknowledging their responsibilities for the plan. A responsible
person shall be on -site at all times during facility operations that have
increased potential to contaminate stormwater runoff through spills or
exposure of materials associated with the facility operations. The SPRP
must be site stormwater specific. Therefore, an oil Spill Prevention Control
and Countermeasure plan (SPCC) may be a component of the SPRP, but
may not be sufficient to completely address the stormwater aspects of the
SPRP. The common elements of the SPCC with the SPRP maybe
incorporated by reference into the SPRP.
4. Preventative Maintenance and Good Housekeeping Program. A preventative
maintenance and good housekeeping program shall be developed and
implemented. The program shall address all stormwater control systems (if
Part IlPage 3of17

Permit No. NCSOOOS72
applicable), stormwater discharge outfalls, all on -site and adjacent surface waters
and wetlands, industrial activity areas (including material storage areas, material
handling areas, disposal areas, process areas, loading and unloading areas, and
haul roads), all drainage features and structures, and existing structural BMPs.
The program shall establish schedules ofinspections, maintenance, and
housekeeping activities of stormwater control systems, as well as facility
equipment, facility areas, and facility systems that present a potential for
stormwater exposure or stormwater pollution where not already addressed
under another element of the SWPPP. Inspection of material handling areas and
regular cleaning schedules of these areas shall be incorporated into the
program. Compliance with the established schedules for inspections,
maintenance, and housekeeping shall be recorded and maintained in the SWPPP.
The program should also address deconstruction, demolition, coal, and/or coal
ash hauling or disposal activities where applicable. The Good Housekeeping
Program shall also include, but not be limited to, BMPs to accomplish the
following:
(a) Minimize contamination of stormwater runoff from oil-bearing equipment in
switchyard areas;
(b) Minimize contamination of stormwater runoff from delivery vehicles and rail cars
arriving and departing the plant site;
(c) Inspect all residue -hauling vehicles for proper covering over the load, adequate
gate sealing, and overall integrity of the container body. Repair vehicles as
necessary; and
(d) Reduce or control the tracking of ash and residue from ash loading and storage
areas;
S. Facility Inspections. Inspections of the facility (including tanks, pipes, and
equipment) and all stormwater systems shall occur as part of the Preventative
Maintenance and Good Housekeeping Program at a minimum on a semi-annual
schedule, once during the first half of the year .(January to June), and once during
the second half (July to December), with at least 60 days separating inspection
dates (unless performed more frequently than semi-annually). These facility
inspections are different from, and in addition to, the stormwater discharge
characteristic monitoring at the outfalls required in Part II B, and C of this permit.
6. Employee Training. Training programs shall be developed and training
provided at a minimum on an annual basis for facility personnel with
responsibilities for: spill response and cleanup, preventative maintenance
activities, and for any of the facility's operations that have the potential to
contaminate stormwater runoff. The facility personnel responsible for
implementing the training shall be identified, and their annual training
shall be recorded in the SWPPP and documented either by the signature of
Part 11 Page 4 of 17

Permit No. NCS000572
each employee trained or by a printout of the electronic record of the
training.
7. Responsible Party. The SWPPP shall identify a specific position or positions
responsible for the overall coordination, development, implementation, and
revision of the SWPPP. Responsibilities for all components of the SWPPP shall
be documented and position assignments provided.
8. SWPPP Amendment and Annual Update. The permittee shall amend the
SWPPP whenever there is a change in design, construction, operation, site
drainage, maintenance, or configuration of the physical features which may
have a significant effect on the potential for the discharge of pollutants to
surface waters. All aspects of the SWPPP shall be reviewed and updated
on an annual basis. The annual update shall include:
(a) An updated list of significant spills or leaks of pollutants for the previous three
(3) years, or the notation that no spills have occurred; (element of the Site
Overview);
(b) A written re -certification that the stormwater outfalls have been evaluated for
the presence of non-stormwater discharges (element of the Site Overview);
(c) A documented re-evaluation of the effectiveness of the on -site stormwater
BMPs (BMP Summary element of the Stormwater Management Strategy).
(d) A review and comparison ofsample analytical data to benchmark values (if
applicable) over the past year, including an evaluation of Tiered Response
status. The permittee shall use the Division's Generic Annual Data
Monitoring Report (DMR) form, available from the Stormwater Permitting
Program's website (See: https://deq.nc.gov/about/divisions/energy-
mineral-land-resources/npdes-stormwater-individual).
If the Director notifies the permittee that the SWPPP does not meet one or more of the
minimum requirements of the permit, the permittee shall have 30 days to respond.
Within 30 days of such notice, the permittee shall submit a time schedule to the
Director for modifying the SWPPP to meet minimum requirements. The permittee shall
provide certification in writing (in accordance with Part III, Standard Conditions,
Section B, Paragraph 3) to the Director that the changes have been made.
9. SWPPP Implementation. The permittee shall implement the Stormwater Pollution
Prevention Plan (SWPPP) and all appropriate BMPs consistent with the provisions of
this permit, in order to control contaminants entering surface waters via stormwater.
Implementation of the SWPPP shall include documentation of all monitoring,
measurements, inspections, maintenance activities, and training provided to
employees, including the log of the sampling data and of actions taken to implement
BMPs associated with the industrial activities, including vehicle maintenance activities.
Such documentation shall be kept on -site for a period of five (5) years and made
available to the Director or the Director's authorized representative immediately upon
request.
Part II Page 5 of 17

Permit No. NCSOOOS72
SECTION B: ANALYTICAL MONITORING REQUIREMENTS
Analytical monitoring of stormwater discharges shall be performed as specified in Tables
1-6. All analytical monitoring shall be performed during a measurable storm event at the
specified stormwater discharge outfalls (SDOs) that discharge stormwater associated with
industrial activity (See Definitions).
A measurable storm event is a storm event that results in an actual discharge from the
permitted site outfall. The previous measurable storm event must have been at least 72 hours
prior. The 72-hour storm interval does not apply if the permittee is able to document that a
shorter interval is representative for local storm events during the sampling period, and the
permittee obtains approval from the local DEMLR Regional Engineer. See Definitions.
The following parameters shall be monitoring during a measurable storm event
discharging from the combined cycle station and substation areas via outfalls SW001
into the Service Water Settling Pond.
Table 1. Analytical Monitoring Requirements for SW001
Discharge
Measurement
Sample
Sample
Characteristics
Units
Fre ` uenc 1
T e2
Location3
PCBs
L
semi-annual
Grab
SDO
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
H
standard
semi-annual
Grab
SDO
Non -Polar Oil & Grease by EPA
mg/L
semi-annual
Grab
SDO
Method 1664 SGT-HEM
Total Nitrogen
mg/L
semi-annual
Grab
SDO
40 CFR Part 423 Appendix A:
semi-annual,
Additional Priority Pollutant
during coal or
Metals - AG, AS, Be, Cd, Cr, Cu,
mg/L
ash transport
Grab
SDO
H , Ni, Pb, Sb, Se, Tl, Zn5
only
semi-annual,
Borons
mg/L
during coal or
Grab
SDO
ash transport
only
Total Rainfall4
inches
semi-annual
I Rain gauge
--
Footnotes:
1 Measurement Frequency: Twice per year (unless other provisions of this permit prompt monthly
sampling) during a measurable storm event, until either another permit is issued for this facility or
until this permit is revoked or rescinded. If the facility is monitoring monthly because of Tier two or
Three response actions under the previous permit, the facility shall continue a monthly monitoring
and reporting schedule in Tier Two or Tier Three status until relieved by the provisions of this
permit or the Division. Monitoring for PCBs may be discontinued after the first year if two
consecutive results are below detection.
2 Grab samples shall be collected within the first 30 minutes of discharge. When physical separation
between outfalls prevents collecting all samples within the first 30 minutes, sampling shall begin within
the first 30 minutes, and shall continue until completed.
Part II Page 6 of 17

Permit No. NCS000572
s Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) unless
representative outfall status (ROS) has been granted. The permittee may petition the Director for ROS
using DEMLR's ROS Request Form. DEMLR may grant ROS if stormwater discharges from a single outfall
are representative of discharges from multiple outfalls. Approved ROS will reduce the number of outfalls
where the analytical sampling requirements apply and will be documented in a letter to their permittee.
A copy of the Division's letter granting ROS shall be kept on site.
4 For each sampled measurable storm event, the total precipitation must be recorded. An on -site rain
gauge is required. Where isolated sites are unmanned for extended periods of time, a local rain gauge
reading may be substituted for an on -site reading.
5 These parameters shall be monitored only if coal or coal ash is transported through the drainage
area of this outfall during the semi-annual monitoring period in Table 7. Mercury shall be
measured by EPA Method 1631E.
The parameters in Table 2 shall be monitored during a measurable storm event
discharging from the materials storage and laydown yard west of the steam station
powerhouse building, via outfalls SWO03, SWO03A, SWO03B (three closely located 12"
culverts), SWO04, SWO05, SWO06, and SWO11 into the Dan River.
At the time of the issuance of this permit the demolition of the adjacent steam station
powerhouse has been completed. The Division may revise the monitoring requirements
below during the upcoming renewal for this permit to reflect final site conditions and
sLorinwal.er pollution risks in these areas.
Table 2. Analytical Monitoring Requirements for SWO03, SWO03A, SW000313,
SWO04, SWO05, SWO06, and SWO11
Discharge;
Measurement
Sample
Sample
Characteristics
Units
Fre' uencyl
Type2
Location3
PCB1
L
semi-annual
Grab
SDO
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
H
standard
semi-annual
Grab
SDO
Non -Polar Oil & Grease by EPA
mg/L
semi-annual
Grab
SDO
Method 1664 SGT-HEM
Total Nitrogen
m L
semi-annual
Grab
SDO
40 CFR Part 423 Appendix A:
semi-annual,
Additional Priority Pollutant
mg/L
during coal or
Grab
SDO
Metals - AG, AS, Be, Cd, Cr, Cu,
ash transport
Hg5, Ni, Pb, Sb, Se, Tl, Zn
only
semi-annual,
Boron
mg/L
during coal or
Grab
SDO
ash transport
only
Total Rainfall4
inches
semi-annual
Rain gauge
--
Footnotes:
1 Measurement Frequency: Twice per year (unless other provisions of this permit prompt monthly
sampling) during a measurable storm event, until either another permit is issued for this facility or
until this permit is revoked or rescinded. If the facility is monitoring monthly because of Tier two or
Three response actions under the previous permit, the facility shall continue a monthly monitoring
and reporting schedule in Tier Two or Tier Three status until relieved by the provisions of this
Part IlPage 7of17

Permit No. NCSOOOS72
permit or the Division. Monitoring for PCBs may be discontinued after demolition is complete
and the area is stabilized, provided two subsequent and consecutive semi-annual results are
below detection.
2 Grab samples shall be collected within the first 30 minutes of discharge. When physical separation
between outfalls prevents collecting all samples within the first 30 minutes, sampling shall begin within
the first 30 minutes, and shall continue until completed.
3 Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) specified above
unless representative outfall status (ROS) has been granted. The permittee may petition the Director for
ROS using DEMLR's ROS Request Form. DEMLR may grant ROS if stormwater discharges from a single
outfall are representative of discharges from multiple outfalls. Approved ROS will reduce the number of
outfalls where the analytical sampling requirements apply and will be documented in a letter to their
permittee. A copy of the Division's letter granting ROS shall be kept on site.
4 For each sampled measurable storm event, the total precipitation must be recorded. An on -site rain
gauge is required. Where isolated sites are unmanned for extended periods of time, a local rain gauge
reading may be substituted for an on -site reading.
S Mercury shall be measured by EPA Method 1631E.
The following parameters shall be monitored during a measurable storm event discharging
from the plant construction staging area north of the combined cycle station, via
outfall SWO07 into the Service Water Settling Pond.
Table 3 Analytical Monitoring Requirements for SWO07
Discharge
Measurement
Sample
Sample
Characteristics
Units
Fre uenc 1
Type2
Location3
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
pH
standard
semi-annual
Grab
SDO
40 CFR Part 423 Appendix A:
semi-annual,
Additional Priority Pollutant
mg/ L
during coal or
Grab
SDO
Metals - AG, AS, Be, Cd, Cr, Cu,
ash transport
H , Ni, Pb, Sb, Se, Tl, Zns
only
semi-annual,
Boron
mg/L
during coal or
Grab
SDO
ash transport
only
Total Rainfall4
inches
semi-annual
Rain gauge
--
Footnotes:
1 Measurement Frequency: Twice per year (unless other provisions of this permit prompt monthly
sampling) during a measurable storm event, until either another permit is issued for this facility or
until this permit is revoked or rescinded. If the facility is monitoring monthly because of Tier two or
Three response actions under the previous permit, the facility shall continue a monthly monitoring
and reporting schedule in Tier Two or Tier Three status until relieved by the provisions of this
permit or the Division.
2 Grab samples shall be collected within the first 30 minutes of discharge. When physical separation
between outfalls prevents collecting all samples within the first 30 minutes, sampling shall begin within
the first 30 minutes, and shall continue until completed.
3 Sample Location: Samples shall be collected at each stormwater discharge outfall (SDO) unless
representative outfall status (ROS) has been granted. The permittee may petition the Director for ROS
using DEMLR's ROS Request Form. DEMLR may grant ROS if stormwater discharges from a single
outfall are representative of discharges from multiple outfalls. Approved ROS will reduce the number of
outfalls where the analytical sampling requirements apply and will be documented in.a letter to their
permittee. A copy of the Division's letter granting ROS shall be kept on site.
Part H Page 8 of 17

Permit No. NCS000572
4 For each sampled measurable storm event, the total precipitation must be recorded. An on -site rain
gauge is required. Where isolated sites are unmanned for extended periods of time, a local rain gauge
reading may be substituted for an on -site reading.
5 These parameters shall be monitored only if coal or coal ash is transported through the drainage
area of this outfall during the semi-annual monitoring period in Table 7. Mercury shall be
measured by EPA Method 1631E.
The following parameters shall be monitored during a measurable storm event discharging
from the plant construction staging area north of the combined cycle station, via
outfall SW0O8 into the Service Water Settling Pond.
Table 4 Analytical Monitoring Requirements for SWOO8
Discharge
Characteristics
Units
Measurement
Fre' uenc 1
Sample
Type2
Sample
Location3
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
H
standard
semi-annual
Grab
SDO
Total Rainfal14
inches
semi-annual
I Rain gauge
--
Footnotes:
1-4 Refer to Table 3, Footnotes 1-4
Outfall SW002 is being added to this NPDES stormwater permit to accommodate a
modification request submitted to the Division by the permittee on July 30, 2020.
The parameters in Table 5 shall be monitored during a measurable storm event
discharging from the decommissioned coal yard, switchyard, and powerhouse,
the decommissioned combustion turbine area, and a portion of the combined
cycle plant, via outfalls SW0O2 and SWOO9. Stormwater sampling for SW002 shall
be performed at the discharge from the culvert on the river side of Edgewood Road.
The permittee has requested that outfall SW009 be removed from this permit when
it is renewed due to the absence of associated industrial activity within the drainage
area of outfall SW009. The request to remove outfall SW009 from this permit will be
reviewed during the renewal application process. To satisfy the requirements of the
existing permit, an inspection will be conducted to determine if the permittee can
discharge via outfall SW009.
Table 5 Analytical Monitoring Requirements for SWO02 and SWO09
Discharge'
Measurement
Sample
Sample
Characteristics
Units
Fre' uenc 1
Type2
Location3
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
H
standard
semi-annual
Grab
SDO
Non -Polar Oil & Grease by EPA
mg/L
Semi-annual
Grab
SDO
Method 1664 SGT-HEM
40 CFR Part 423 Appendix A:
semi-annual,
Additional Priority Pollutant
mg/L
during coal or
Grab
SDO
Metals - AG, AS, Be, Cd, Cr, Cu,
ash transport
Hg, Ni, Pb, Sb, Se, Tl, Zns
only
Part II Page 9 of 17

Permit No. NCS000572
Discharge
Characteristics
Units
Measurement
Fre' uenc 1
Sample
Type2
Sample
Location3
semi-annual,
Boron
mg/L
during coal or
Grab
SDO
ash transport
only
Total Rainfa114
inches
semi-annual
Rain gauge
--
Footnotes:
1-4 Refer to Table 3, Footnotes 1-4
5 Mercury shall be measured by EPA Method 1631E.
The sampling location of outfall SW010 has been specified in the following paragraph to
accommodate a modification request submitted to the Division by the permittee on July 30,
2020.
The parameters in Table 6 shall be monitored during a measurable storm event
discharging from the ash stacks, construction staging area, and substation, via
stormwater outfall SWO1O into the Dan River. Stormwater sampling for outfall SW010
shall be performed at the culvert on the wetland side of the landfill access road.
To satisfy the requirements of the existing permit, an inspection will be conducted to
determine if the permittee can discharge via outfall SW010.
Table 6 Analytical Monitoring Re uirements for SW010
Discharge
Characteristics
Units
Measurement
Freguencyl
Sample
Type2
Sample
Location3
PCB1
g/L
Semi-annual
Grab
SDO
Total Suspended Solids (TSS)
m L
semi-annual
Grab
SDO
pH
standard
semi-annual
Grab
SDO
40 CFR Part 423 Appendix A:
Additional Priority Pollutant
Metals - AG, AS, Be, Cd, Cr, Cu,
H 5, Ni, Pb, Sb, Se, Tl, Zn
mg/L
semi-annual
Grab
SDO
Boron
m L
semi-annual
Grab
SDO
Total Rainfal14
inches
semi-annual
I Rain gauge
--
Footnotes:
1-4 Refer to Table 3, Footnotes 1-4
5 Mercury shall be measured by EPA Method 1631E.
Part II Page 10 of 17

Permit No. NCSOOOS72
Should the permittee identify or create any new stormwater outfalls not addressed in
this permit; remove any stormwater outfalls identified in this permit; or alter any
drainage areas that change the potential pollutants in runoff discharged through
corresponding outfalls, the permittee will submit a request to NC DEMLR to modify this
permit. For any newly discovered pipes or outfalls, the permittee must evaluate the
structure and provide a report of the status and planned actions to NC DEQ within 14 days.
The permittee must either (1) request modification of this permit and modify the SWPPP
accordingly, or (2) eliminate potential discharges by removal, plugging, or combination of
both.
The permittee shall complete the analytical samplings in accordance with the schedule
specified in Table 7, unless adverse weather conditions prevent sample collection (see
Adverse Weather in Definitions). A minimum of 60 days must separate Period 1 and
Period 2 sample dates, unless monthly monitoring has been instituted under a "Tier Two"
response. Inability to sample because of adverse weather conditions must be documented
in the SWPPP and recorded on the DMR. The permittee must report the results from each
sample taken within the monitoring period (see Part III, Section E). IIowever, for purposes
of benchmark comparison and Tiered response actions, the permittee shall use the
analytical results from the first sample with valid results within the monitoring period.
Table 7. Analytical Monitoring Schedule
Monitoring Period','
Sample Number
Start
End
Year 1 - Period 1
1
October 1, 2015
June 30, 2016
Year 1 - Period 2
2
July 1, 2016
December 31, 2016
Year 2 - Period 1
3
January 1, 2017
June 30, 2017
Year 2 - Period 2
4
July 1, 2017
December 31, 2017
Year 3 - Period 1
5
January 1, 2018
June 30, 2018
Year 3 - Period 2
6
July 1, 2018
December 31, 2018
Year 4 - Period 1
7
January 1, 2019
June 30, 2019
Year 4 - Period 2
8
July 1, 2019
December 31, 2019
Year 5 - Period 1
9
January 1, 2020
June 30, 2020
Year 5 - Period 2
10
July 1, 2020
September 30, 2020
Footnotes:
1 Maintain semi-annual monitoring until either another permit is issued for this facility or until this
permit is revoked or rescinded. The permittee must submit an application for renewal of coverage
before the submittal deadline (180 days before expiration) to be considered for renewed coverage
under the permit. The permittee must continue analytical monitoring throughout the permit renewal
process, even if a renewal permit is not issued until after expiration of this permit.
2 If no discharge occurs during the sampling period, the permittee must submit a monitoring report
indication "No Flow" or "No Discharge" within 30 days of the end of the sampling period.
Part Il Page 11 of 17

Permit No. NCS000572
Failure to monitor semi-annually per permit terms may result in the Division requiring
monthly monitoring for all parameters for a specified time period. "No discharge" from an
outfall during a monitoring period does not constitute failure to monitor, as long as it is
properly recorded and reported.
Proposed NPDES Wastewater Permit NC0003468 requires the facility to conduct
fish tissue monitoring once during that permit term for arsenic (As), selenium
(Se), and mercury (Hg) in accordance with a Sampling Plan approved by the
Division of Water Resources. The permittee shall submit a copy of fish tissue
monitoring results to the DEMLR Stormwater Permitting Program (Central Office)
within 30 days of receiving results and indicate the location of sampling in relation
to stormwater discharge outfalls. This reporting timeframe differs from the NPDES
Wastewater Permit, which directs that fish tissue analysis results be submitted with
the wastewater discharge permit renewal application.
The permittee shall compare monitoring results to the benchmark values in Table 8.
Exceedances of benchmark values require the permittee to increase monitoring,
increase management actions, increase record keeping, and/or install storinwaler Bess.
Management Practices (BMPs) in a tiered program. See below the descriptions of Tier
One, Tier Two, and Tier Three response actions below. In the event that the Division
releases the permittee from continued monthly monitoring and reporting under Tier
Two or Tier Three, the Division's release letter may remain in effect through
subsequent reissuance of this permit, unless the release letter provides for other
conditions or duration.
Table 8. Benchmark Values for Analytical Monitoring
Discharge Characteristics
Units
Benchmark
Antimony (Sb), Total Recoverable
mg/L
0.09
Arsenic (As), Total Recoverable
mg/L
0.34
Beryllium (Be), Total Recoverable
mg/L
0.065
Cadmium (Cd), Total Recoverable 1
mg/L
0.003
Chromium (Cr), Total Recoverable 1
mg/L
0.9
Copper (Cu), Total Recoverable 1
mg/L
0.010
Lead (Pb), Total Recoverable 1
mg/L
0.075
Mercury (Hg), Total Recoverable 2
ng/L
N/A2
Nickel (Ni), Total Recoverable 1
mg/L
0.335
Polychlorinated biphenyl compounds (PCBs)
g/L
Detected
Selenium (Se), Total Recoverable
mg/L
0.056
Part lI Page 12 of 17

Permit No. NCS000572
Silver (Ag), Total Recoverable 1
mg/L
0.0003
Zinc (Zn), Total Recoverable 1
mg/L
0.126
Total Suspended Solids (TSS)
mg/L
100
Non -Polar Oil & Grease by
EPA Method 1664 (SGT-HEM)
mg/L
15
Total Nitrogen
mg/L
30
pH3
standard
6- 93
Boron (B)
mg/L
mg/L
N/A (monitor only)
N/A (monitor only)
Thallium (Tl), Total Recoverable)
Footnotes:
1 Hardness- dependent. Benchmark based on translation of dissolved value into total recoverable with an
assumed hardness of 25 mg/1 and a total suspended solids (TSS) concentration of 10mg/L.
2 Values above the North Carolina water quality standard for mercury (12ng/1) should be noted on the
DMR but do not trigger Tier responses. Concentrations infield blanks or method banks associated with
the sample may be subtracted from the results for that sample, as long as all documentation of the
adjustment is provided with the DMR.
3 If pH values of less than 6 are recorded, but ambient precipitation pH levels are lower, then the lower
threshold of this benchmark range is the pH of the precipitation (within instrument accuracy) instead of
6 S.U. Readings from an on -site or local rain gauge (or local precipitation data) must be documented to
demonstrate background concentrations were below the benchmark pH range of 6-9.
The benchmark values in Table 8 are not permit limits but should be used as
guidelines for implementation of the permittee's SWPPP. An exceedance of a
stormwater benchmark value is not a permit violation; however, failure to
respond to the exceedance as outlined in this permit is a violation of permit
conditions.
If: The first valid sampling results are above a benchmark value, or outside of the benchmark range,
for any parameter at any outfall;
Then: The permittee shall:
1. Conduct a stormwater management inspection of the facility within two weeks of receiving
sampling results.
2. Identify and evaluate possible causes of the benchmark value exceedance.
3. Evaluate potential and select specific source controls, operational controls, and/or physical
improvements to reduce concentrations of the parameter(s) of concern and bring
concentrations within the benchmark range.
4. Implement the selected controls/improvements within two months of the inspection.
S. Record each instance of a Tier One response in the SWPPP. Include the date and value of the
benchmark exceedance, the inspection date, the personnel conducting the inspection, the
selected actions, and the date the selected actions were implemented.
Note: A benchmark exceedance triggers a Tier One response for each parameter.
Part II Page 13 of 17

Permit No. NCSOOOS72
Tier Two
If. The first valid sampling results from two consecutive monitoring are above the benchmark values,
or outside of the benchmark range, for any specific parameter at a specific discharge outfall;
Then the permittee shall:
1. Repeat all the required actions outlined above in Tier One.
2. Immediately institute monthly monitoring and reporting for all analytical monitoring
parameters. The permittee shall conduct monthly monitoring at every outfall where a sampling
result exceeded the benchmark value for two consecutive samples. Monthly (analytical and
qualitative) monitoring shall continue until three consecutive sample results are below the
benchmark values or within benchmark range.
3. If no discharge occurs during the sampling period, the permittee is required to submit a monthly
monitoring report indicating "No Flow" to comply with reporting requirements.
4. Alternatively, in lieu of steps 2 and 3, the permittee may, after two consecutive exceedances,
exercise the option of contacting the DEMLR Regional Engineer as provided below in Tier Three.
The Regional Engineer may require additional response actions on the part of the permittee as
provided in Tier Three, including reduced or additional sampling parameters or frequency.
S. Maintain a record of the Tier Two response in the SWPPP.
6. Continue Tier Two response obligations until a new periniL is issued.
Table S. Tier Three Requirements
Tier Three
If: The valid sampling results required for the permit monitoring periods exceed the benchmark value, or
are outside the benchmark range, for any specific parameter at any specific outfall on four occasions, the
permittee shall notify the DEMLR Regional Engineer in writing within 30 days of receipt of the fourth
analytical results;
Then: The Division may but is not limited to:
• require that the permittee revise, increase, or decrease the monitoring and reporting
frequency for some or all of the parameters herein;
• require sampling additional or substitute parameters;
• require the permittee to install structural stormwater control measures;
• require the permittee implement other stormwater control measures
• require the permittee Perform upstream and downstream monitoring to characterize
impacts on receiving waters; or
• require the permittee implement site modifications to qualify for a No Exposure Exclusion;
• require the permittee to continue Tier Three obligations through the permit renewal
process.
Stormwater discharges enter the Dan River at a portion of the river that is subject to a
TMDL for fecal coliform, and to the state-wide TMDL for mercury. If this portion of the
Dan River becomes impaired for other pollutants, or if additional TMDLs are approved,
the permittee may be required to monitor for the pollutant(s) of concern in the future
and submit results to the Division. The Division will consider the monitoring results in
Part II Page 14 of 17

Permit No. NCS000572
determining whether additional BMPs are needed to control the pollutant(s) of concern
to the maximum extent practicable.
If additional BMPs are needed to achieve the required level of control in response to
existing or future impairments or approved TMDLs, the permittee will be required to
(1) develop a strategy for implementing appropriate BMPs, and (2) submit a timetable
for incorporation of those BMPs into the Stormwater Pollution Prevention Plan.
SECTION C: QUALITATIVE MONITORING REQUIREMENTS
The purpose of qualitative monitoring is to evaluate the effectiveness of the Stormwater
Pollution Prevention Plan (SWPPP) and identify new potential sources of stormwater
pollution. Qualitative monitoring of stormwater outfalls must be performed during a
measurable storm event.
Qualitative monitoring requires a visual inspection of each stormwater outfall regardless of
representative outfall status. Qualitative monitoring shall be performed quarterly as
specified in Table 9, and during required analytical monitoring events (unless the permittee
is required to perform further qualitative monitoring per the Qualitative Monitoring
Response, below). Inability to monitor because of adverse weather conditions must be
documented in the SWPPP and recorded on the Qualitative Monitoring Report form (see
Adverse Weather in Definitions). Only SDOs discharging stormwater associated with
industrial activity must be monitored (See Definitions).
In the event an atypical condition is noted at a stormwater discharge outfall, the permittee
shall document the suspected cause of the condition and any actions taken in response to
the discovery. This documentation will be maintained with the SWPPP.
Table 9. Qualitative Monitoring Requirements
Discharge Characteristics
Frequencyl
Monitoring
Location2
Color
quarterly
SDO
Odor
quarterly
SDO
Clarity
quarterly
SDO
Floating Solids
quarterly
SDO
Suspended Solids
quarterl
SDO
Foam
quarterly
SDO
Oil Sheen
uarterly
SDO
Erosion or deposition at the outfall
quarterly
SDO
Other obvious indicators
of stormwater pollution
quarterly
SDO
Footnotes:
Part II Page 15 of 17

Permit No. NCS000S72
Monitoring Frequency: Four times per year during a measurable storm event unless other provisions of
this permit prompt monthly monitoring. See Table 10 for schedule of monitoring periods through the end
of this permitting cycle. The permittee must continue qualitative monitoring throughout the permit
renewal process until a new permit is issued.
Monitoring Location: Qualitative monitoring shall be performed at each stormwater discharge outfall
(SDO) regardless of representative outfall status.
Table 10. Qualitative Monitoring Schedule
Monitoring period,i,2
Sample Number
Start
End
Year 1 - Period 1
1
October 1, 2015
December 31, 2015
Year 1 - Period 2
2
January 1, 2016
March 31, 2016
Year 1 - Period 3
3
April 1, 2016
June 30, 2016
Year 1 - Period 4
4
July 1, 2016
September 30, 2016
Year 2 - Period 1
5
October 1, 2016
December 31, 2016
Year 2 - Period 2
6
January 1, 2017
March 31, 2017
Year 2 - Period 3
7
April 1, 2017
June 30, 2017
Year 2 - Period 4
8
July 1, 2017
September 30, 2017
Year 3 - Period 1
9
October 1, 2017
December 31, 2017
Year 3 - Period 2
10
January 1, 2018
March 31, 2018
Year 3 - Period 3
11
April 1, 2018
June 30, 2018
Year 3 - Period 4
12
July 1, 2018
September 30, 2018
Year 4 - Period 1
13
October 1, 2018
December 31, 2018
Year 4 - Period 2
14
January 1, 2019
March 31, 2019
Year 4 - Period 3
15
April 1, 2019
June 30, 2019
Year 4 - Period 4
16
July 1, 2019
September 30, 2019
Year 5 - Period 1
17
October 1, 2019
December 31, 2019
Year 5 - Period 2
18
January 1, 2020
March 31, 2020
Year 5 - Period 3
19
April 1, 2020
June 30, 2020
Year 5 - Period 4
20
July 1, 2020
September 30, 2020
Footnotes:
1 Maintain quarterly monitoring until either another permit is issued for this facility or until this permit is
revoked or rescinded. The permittee must continue qualitative monitoring throughout the permit renewal
process, even if a renewal permit is not issued until after expiration of this permit.
2 If no discharge occurs during the sampling period, the permittee must complete a monitoring report
indicating "No Flow" or "No Discharge" within 30 days of the end of the sampling period.
Failure to monitor quarterly per permit terms may result in the Division requiring
monthly monitoring for all parameters for a specified time period. "No discharge" from an
outfall during a monitoring period does not constitute failure to monitor, as long as it is
properly recorded.
If the permittee's qualitative monitoring indicates that existing stormwater BMPs are
ineffective, or that significant stormwater contamination is present, the permittee shall
investigate potential causes, evaluate the feasibility of corrective actions, and implement
those corrective actions within 30 days, per the Qualitative Monitoring Response, below.
Part II Page 16 of 17

Permit No. NCS000572
A written record of the permittee's investigation, evaluation, and response actions shall be
kept in the Stormwater Pollution Prevention Plan.
Qualitative monitoring is for the purposes of evaluating SWPPP effectiveness, identifying new
potential sources of stormwater pollution, and prompting the permittee's response to pollution. If
the permittee repeatedly fails to respond effectively to correct problems identified by qualitative
monitoring, or if the discharge causes or contributes to a water quality standard violation, then the
Division may but is not limited to:
• requires that the permittee revise, increase, or decrease the monitoring frequency for some
or all parameters (analytical or qualitative);
• require the permittee to install structural stormwater controls;
• require the permittee to implement other stormwater control measures;
require the permittee to perform upstream and downstream monitoring to characterize
impacts on receiving waters; or
require the permittee implement site modifications to qualify for a No Exposure Exclusion.
Part IlPage 17of17