NCS000580 fact sheet binder 2023

DEQ / DEMLR
FACT SHEET FOR NPDES INDUSTRIAL INDIVIDUAL
STORMWATER PERMIT DEVELOPMENT
Basic Information for Permit Issuance and Renewals:
Permit Writer/Date Brianna Young 7/26/2023
Permit Number NCS000580
Owner/Facility Name Duke Energy Progress,LLC/Mayo Steam Electric
Power Plant
SIC AICS Code/Category 4911 /Power Generation
Basin Name/Sub-basin number Roanoke/03-02-05
Receiving Stream/HUC 001: Bowes Branch/030101040603
002: Bowes Branch/030101040603
002a: Bowes Branch/030101040603
003: Bowes Branch/030101040603
006a: Mayo Reservoir/030101040605
010: Mayo Reservoir/030101040605
Stream Classification/Stream Segment 001: C/22-58-14
002: C/22-58-14
002a: C/22-58-14
003: C/22-58-14
006a: WS-V/22-58-15-(0.5)
010: WS-V/22-58-15- 0.5
Is the stream impaired [on 303(d) list]? No
Any TMDLs? No
Any threatened and/or endangered species? No
Any compliance concerns? See Section 2 below
Any permit mods since lastpermit? See Section 1 below
New expiration date 8/31/2028
Comments on Draft Permit? See Section 6 below
Section 1. Facility Activities and Process:
The Duke Energy Progress, LLC Mayo Electric Generating Plant is a dual boiler coal fired electric
generating plant with a net generating capacity of 745 megawatts. The monofill receives only coal
combustion residuals. A public hearing was held in 2016 during the previous permit review and
issuance.
Per the 2020 permit renewal application, all process water redirect work, including grading to remove all
process flows from the ash basin to a newly constructed lined retention basin, was completed.
Otherwise, no changes have occurred in the drainage areas of the three existing outfalls. However, Duke
Energy would like to add the three stormwater outfalls from the Mayo Monofill (Outfalls 001, 002, and
003) and not renew NCG120101, which the monofill outfalls are currently covered under. NCG120101
has had trouble with fecal coliform monitoring due to the abundant wildlife around the monofill. The
industrial activity at the monofill, transport of materials, is similar in nature to the activity at the
Station's stormwater outfall 010.
Outfall SW001: Monofill
Drainage area includes trucks hauling conditioned ash(ash mixed with water or brine to minimize dust),
off specification gypsum, and other approved monofill waste.
Page 1 of 8

Outfall SW002: Monofill
Drainage area includes trucks hauling conditioned ash(ash mixed with water or brine to minimize dust),
off specification gypsum, and other approved monofill waste.
Outfall SW003: Monofill
Drainage area includes trucks hauling conditioned ash(ash mixed with water or brine to minimize dust),
off specification gypsum, and other approved monofill waste.
Outfall SW006a: Cooling Towe
Discharge area includes mobile equipment utilization. Potential pollutants include: Petroleum and
herbicides.
Outfall SW007: Formerly SW002, Discharge to Bowes Branch
Drainage area includes the railroad corridor for coal delivery, a stockpile area and equipment storage for
an active construction project, a temporary construction trailer, a permanent facility warehouse, a
permanent facility material stockpile, and equipment staging areas.
Outfall SWO10: Access Road
Drainage area includes vehicular traffic from flue gas desulfurization system and ash handling system.
This will include trucks hauling conditioned ash(ash mixed with water to minimize dust), limestone for
injection into the stack as part of the flue gas desulfurization system, and gypsum(by-product of the
FGD process).
Additional Outfalls:
Per the previous stormwater permit: Outfalls 004, 005 006c, 006d, and 006e are included in wastewater
NPDES permit NC0038377 due to potential non-stormwater discharge. Outfall 006b does not have a
defined point source discharge. Without a point source this outfall is not covered by the NPDES
stormwater program and is not included in this permit.
Why Industrial Sites with Stormwater are Subject to a Permit: Federal NPDES regulations define
stormwater discharge associated with industrial activity in 40 CFR §122.26 (b)(14) as: "the discharge
from any conveyance that is used for collecting and conveying storm water and that is directly related to
manufacturing,processing or raw materials storage areas at an industrial plant. The term does not
include discharges from facilities or activities excluded from the NPDES program under this part 122.
For the categories of industries identified in this section, the term includes, but is not limited to, storm
water [sic] discharges from industrial plant yards; immediate access roads and rail lines used or traveled
by carriers of raw materials, manufactured products, waste material, or byproducts used or created by
the facility; material handling sites; refuse sites; sites used for the application or disposal of process
waste waters (as defined at part 401 of this chapter); sites used for the storage and maintenance of
material handling equipment; sites used for residual treatment, storage, or disposal; shipping and
receiving areas; manufacturing buildings; storage areas (including tank farms) for raw materials, and
intermediate and final products; and areas where industrial activity has taken place in the past and
significant materials remain and are exposed to storm water. For the purposes of this paragraph, material
handling activities include storage, loading and unloading, transportation, or conveyance of any raw
material, intermediate product, final product, byproduct or waste product. The term excludes areas
located on plant lands separate from the plant's industrial activities, such as office buildings and
accompanying parking lots as long as the drainage from the excluded areas is not mixed with storm
water [sic] drained from the above described areas."
Page 2 of 8

Section 2. Monitoring Information and Compliance History:
• NCS000580: March 2017 to January 2022, benchmarks exceeded for:
o SWO02: Copper 2x, Mercury 3x, Zinc Ix, TSS Ix
o SWO06a: Copper 3x, Selenium Ix, Mercury 3x
o SWO10: pH lx, Copper lx, O&G 2x, Mercury 7x
• NCG120101: December 2014 to May 2022,benchmarks exceeded for:
o SW001: Selenium Ix, Fecal coliform Ix, Copper Ix, Mercury 2x, Zinc Ix
o SWO02: COD Ix, TSS Ix, Selenium Ix, Fecal coliform 3x, Copper 2x, Mercury 2x,
Zinc Ix
o SWO03: TSS 2x, Selenium Ix, Fecal coliform 3x, Copper 2x, Mercury 2x, Zinc Ix
• PCB monitoring was not performed during the previous permit cycle as required
• Fish tissue data submitted for April 2017 to May 2019
o Per permit renewal application,prior to 2019, the Mayo Reservoir Trace Element fish
sampling program focused on plant operations in respect to sustainable fish populations.
With the implementation of flue gas desulfurization, zero liquid discharge system and ash
basin modifications, water column and fish tissue concentration for various metals have
declined since 2014.
Section 3. Proposed Monitoring for Stormwater Discharges:
The Division considered potential pollutants from past and present industrial activities (coal-fired
electric generation) and data was submitted for March 2017 to January 2022. Quantitative sampling
included pH, TSS, O&G, boron, antimony, arsenic, beryllium, cadmium, chromium, copper, lead,
nickel, selenium, silver, thallium, zinc, and mercury.
Parameters are based on potential pollutants in the drainage area, sampling results, and in some cases,
dependent upon future activities (e.g., ash removal through the drainage area). Below is a table of the
proposed monitoring for each outfall at the Mayo Steam Electric Power Plant site.
Outfalls SWO01, SWO02, SWO03, SWO06, SWO07, and SW010
Quarterly monitoring
Total Suspended Solids BASIS: Potential pollutant from drainage area and BMP effectiveness
(TSS) indicator. These outfalls may be impacted by coal combustion waste
constituents (CCW).
Quarterly monitoring
H BASIS: Pollutant indicator and important to interpreting toxicity potential
p of metals.
Quarterly monitoring
Total Rainfall BASIS: Discharge potential indicator
Quarterly monitoring
Non-Polar Oil &Grease BASIS: Potential pollutant from lubricants; Method 1664 SGT-HEM
targets petroleum-based O&G
Monthly Oil Usage Quarterly monitoring
BASIS: Potential pollutant from drainage area
Page 3 of 8

Quarterly monitoring
PCBs BASIS: Potential pollutant from drainage area
Quarterly monitoring
Total Antimony BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Arsenic BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Beryllium BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Boron BASIS: Coal combustion waste (CCW) constituent/coal tracer.
Quarterly monitoring
Total Cadmium BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Chromium BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Copper BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Lead BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Nickel BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Selenium BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Silver BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Thallium BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Mercury BASIS: Coal combustion waste (CCW) constituents.
Quarterly monitoring
Total Zinc BASIS: Coal combustion waste (CCW) constituents.
Total Hardness Quarterly monitoring
BASIS: Hardness dependent metals must be monitored
Page 4 of 8

Stormwater Benchmarks and Tiered Response: Rather than limits,North Carolina NPDES
Stormwater permits contain benchmark concentrations. Stormwater benchmarks are numerical action
levels for stormwater monitoring. Benchmarks are not effluent limits, and benchmark exceedances are
not permit violations. Benchmarks provide facilities a tool for assessing the significance of pollutants in
stormwater discharges and the effectiveness of best management practices (BMPs). Benchmark
concentrations are intended as guidelines for the facility's development and implementation of the
Stormwater Pollution Prevention Plan(SWPPP).
Benchmark exceedances require the permittee to increase monitoring, increase management actions,
increase record keeping, and/or install stormwater BMPs in a tiered program. The permit establishes a
tiered approach to specify actions the permittee must take in response to analytical results above
benchmark concentrations. The tiered structure of the permit provides the permittee and DEMLR wide
flexibility to address issues that may arise with one or more parameters and/or outfalls.
Metals benchmarks are calculated to mimic acute water quality standards and with the guidance of
DWR. NC DWR follows established federal procedures for calculating acute standards when developing
the benchmarks. Just like the acute standards, metals benchmarks normally reflect one half of the
calculated Final Acute Value (the "1/2 FAV"). In most cases, translation into total recoverable values is
based on an assumed hardness of 25 mg/L and a total suspended solids (TSS) concentration of 10 mg/L.
Acute standards protect aquatic life from negative impacts of short-term exposure to higher levels of
chemicals where the discharge enters a waterbody. The Stormwater Permitting Program applies this
approach because of the ephemeral nature of rainfall events.
The Division may evaluate results to determine if a smaller suite of parameters for some outfalls is
adequate to characterize potential pollution or BMP effectiveness. For example, one or more metals or
other parameters may serve as an adequate tracer for the presence of ash pollution during disturbance or
ash removal in specific drainage areas at this site. For parameters that do not have a stormwater
benchmark, the Division may develop a benchmark value if appropriate toxicity data become available
or if rising trends in concentrations suggest a persistent source.
A summary of the benchmarks in the draft permit, and their basis, is below:
Parameter Benchmark Basis
Total Suspended 100 mg/L National Urban Runoff Program(NURP) Study, 1983
Solids TSS
H 6 s.u. —9 s.u. NC Water Quality Standard(Range)
Non-Polar Oil & Review of other state's daily maximum benchmark
Grease 15 mg/L concentration for this more targeted O&G;NC WQS that
EPA Method 1664 does not allow oil sheen in waters
SGT-HEM
Antimony Total 340 /L Acute Aquatic Criterion, '/2 FAV
Arsenic Total 340 /L Acute Aquatic Criterion, '/2 FAV
Beryllium Total 65 µg/L Acute Aquatic Criterion, '/2 FAV
Boron 34,000 µg/L CCW/Coal constituent;Narrative National Recommended
Water Qualit Criterion
Cadmium Total 3 µ 7/L Acute Aquatic Criterion, '/2 FAV
Page 5 of 8

1/2 FAV; Based on(Cr III+Cr VI) acute thresholds and
Chromium (Total) 905 µg/L assumption that industrial activities here are not a source of
hexavalent chromium
Copper Total 10 /L Acute Aquatic Criterion, 1/2 FAV
Lead Total 750 /L Acute Aquatic Criterion, '/2 FAV
Mercury Total 12 n /L CCW/Coal Constituent; Chronic 02B standard
Nickel Total 335 /L Acute Aquatic Criterion, 1/2 FAV
Selenium(Total) 5 µg/L 1/2 FAV,NC-specific, based on 1986 Study on Se impacts in
NC
Silver Total 0.3 /L Acute Aquatic Criterion, 1/2 FAV
Thallium Total 2,000 CCW/Coal constituent; Based on EPA Safe Drinking Water
(Total) µg/L Act MCL
Zinc Total 126 /L Acute Aquatic Criterion, 1/2 FAV
There shall be The aquatic life standard is 0.001 µg/L. The detection limits
PCBs no discharge of for Arochlors 1016, 1221, 1232, 1242, 1248, 1254, 1260, and
PCB
compounds 1262 are 1 µg/L.
Stormwater Pollution Prevention Plan: The proposed permit conditions reflect the EPA and NC's
pollution prevention approach to stormwater permitting. The Division's maintains that implementation
of Best Management Practices (BMPs) and traditional stormwater management practices that control the
source of pollutants meets the definition of Best Available Technology (BAT) and Best Conventional
Pollutant Control Technology(BCT). The permit conditions are not numeric effluent limitations but are
designed to be flexible requirements for implementing site-specific plans to minimize and control
pollutants in stormwater discharges associated with the industrial activity. Title 40 Code of Federal
Regulations (CFR) §122.44(k)(2) authorizes the use of BMPs in lieu of numeric effluent limitations in
NPDES permits when the agency finds numeric effluent limitations to be infeasible. The agency may
also impose BMP requirements which are "reasonably necessary" to carry out the purposes of the Act
under the authority of 40 CFR 122.44(k)(3). The conditions proposed in this draft permit are included
under the authority of both of these regulatory provisions. In essence, the pollution prevention and BMP
requirements operate as limitations on effluent discharges that reflect the application of BAT/BCT.
Mercury Monitoring Requirements: The proposed permit requires mercury to be measured in
stormwater samples by EPA Method 1631E, which can detect levels as low as 0.5 ng/l. This requirement
is consistent with recent federal rule-making that requires NPDES permittees to monitor discharges with
sufficiently sensitive test procedures approved under 40 CFR §136. Modifications to 40 CFR §122.44(i)
require a method that has a minimum level (ML) at or below the effluent limit(not applicable here), or
the lowest minimum level (ML) of EPA approved analytical methods for the measured parameter. Based
on results, Method 1631E will be required to quantify levels in these discharges. NC DEMLR
understands that this method is more costly and requires a more intensive sampling protocol than most
other parameters, and that fish tissue sampling will be provided during the permit cycle. Therefore, no
benchmark applies that would trigger tiered response actions. Proposed permit provisions also allow the
permittee to use field blank and/or method blank concentrations to adjust reported mercury levels as
long as documented is submitted with the Data Monitoring Report DMR).
Flexibility in Tier Responses: Tier Two actions provide an opportunity for the permittee to propose an
alternative monitoring plan for approval by the Region:
• 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
Page 6 of 8

Three. The Regional Engineer may direct the response actions on the part of the permittee as
provided in Tier Three, including reduced or additional sampling parameters or frequency.
• If pursuing the alternative above after two consecutive exceedances, the permittee may propose
an alternative monitoring plan for approval by the Regional Engineer.
The permit therefore allows the permittee to petition the Regional Office for monitoring changes sooner
than Tier Three (upon any four benchmark exceedances) and gives guidance on one option to take. For
example, the permittee may request that mercury only be monitored semi-annually under the tiers, or
that only parameters over the benchmark be monitored more frequently. In this way, changes to the
monitoring scheme for any outfall could be handled outside of a permit modification.
Other Proposed Requirements:
• It is standard for Stormwater Pollution Prevention Plan(SWPPP)requirements to include an
annual certification that stormwater outfalls have been evaluated for the presence of non-
stormwater discharges, and if any are identified, how those discharges are permitted or otherwise
authorized.
• Requirement to submit a request for permit modification if the facility identifies or creates any
new outfalls, removes outfalls, or alters any drainage area that changes potential pollutants.
• The Division expects the permittee to apply best professional judgment and consider the safety
of its personnel in fulfilling sampling obligations under the permit.
• Federal regulations require electronic submittal of all discharge monitoring reports (DMRs). If a
state does not establish a system to receive such submittals, then permittees must submit DMRs
electronically to the EPA.
• Quarterly QualitativeNisual Monitoring to assure regular observation of outfalls throughout
year.
Section 4. Chanp_es from previous permit to draft:
• Monitoring increased from semi-annually to quarterly for all parameters (qualitative and
quantitative)
• "No discharge" clarifications made
• eDMR requirement added
• Feasibility study removed per SW program guidelines
• Boilerplate language moved into body of the permit; boilerplate no longer attached
• Monitoring for total hardness added for outfalls SW006, SW007 (formerly SW002) and SWO10
as monitoring for hardness dependent metals is required
• Benchmarks updated for parameters per guidance from DWR Standards group on stormwater
benchmarks
• Outfalls SW001, new SW002, and SW003 added from NCG210101 per permittee's request
o New monitoring requirements assigned to each outfall (different from what NCG120101
required)
• Existing Outfall SW002 has been renumbered as Outfall SW007 to accommodate new outfalls
added
Page 7 of 8

Section 5. Changes from draft to final:
• Part B has had references to coal ash clean-up added back in
o Information mistakenly removed in draft permit
• Footnote added under Table I that PCB monitoring may cease after the first year
o Footnote mistakenly left off draft permit
Section 6. Discussions with the Facility and Regional Office:
• Initial contact with facility: 8/5/2022
• Initial contact with Regional Office: 8/5/2022
• Draft sent to CO peer review: 5/17/2023
• Draft sent to Regional Office: 6/14/2023
• Final permit sent for supervisor signature: 7/26/2023
Section 7. Comments received on draft permit:
• Shawn Guyer (PWS; via email 7/3/2023): The PWS Section concurs with the issuance of this
permit provided the facility is operated and maintained properly, the stated effluent limits are
met prior to discharge, and the discharge does not contravene the designated water quality
standards.
• Lori Tollie (Duke Energy; via email 6/30/2023): We have reviewed the Mayo Draft ISW and
have one question. In the previous permit after 2 non detects for PCBs we could discontinue
monitoring. Is that still the process?
o DEMLR response: The footnote was inadvertently left off the draft permit. The permit
will be corrected to add the footnote back in before a decision is made on the final permit.
Page 8 of 8

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AFFIDAVIT OF PUBLICATION
Account# OrderNumher Identification Order PO Amount Cols Depth
38106 4M9 I Print Legal Ad-IPLO470810-IPLO1270BI $47750 2 24L
Attention: Joyce Sanford Clark STATE OF NORTH CAROLINA
NC DENR ENGERGY MINERAL&LAND RESOURCES COUNTY OF WAKE,COUNTY OFDURHAM
1612 MAIL SERVICE CENTER Before the undersigned,a Notary Public of Dallas
RALEIGH,NC 276991612 County,Texas,duly commissioned and authorized to
administer oaths,affirmations,etc.,personally
[e-mail] appeared Tara Pennington,who being duly sworn or
affirmed,according to law,doth depose and say that he
ORTHCAENVI ENVIRONMENTAL orsheis Accounts Receivable Specialist oftheNews&
NORTH TCO MI ENVIRONMENTAL
MANAGEMENT INATERDISC ARENTTOISSUE ; Observer Publishing Company,a corporation organized
NPDESSTORMwATERgement DISCHARGE PERMITS ; and doing business under the Laws of the State of North
The North Caroline Environmental Management Commission proposes to issue g
NPDES stonnwater tlischarge pennit(9)to the person(s) listed below.Public Carolina.and publishing a newspaper known as The
comment or objection to the draft permits is invited.Written comments regarding News&Observer,Wake and State aforesaid,the said
the proposed pemml will be accepted until 30 days after the publish date of this
notice and considered In the linal determination regarding permit issuance and ; newspaper in which such notice,paper,document,or
Rental provisions.The Director of the NC Division of Energy,Mineral,and Land legal advertisement was published was,at the time of
Resources(DEMLR)may hold a public hearing should mere be a sign4cant
degree of public interest.Please mail comments and/or irdomalon requests to each and every such publication.a newspaper meeting
DEMLR at 1612 Mail Service Carder,Raleigh,NO 27699-1612. all of the requirementsand ualificationsofSectionl-
• Duke Energy Progress,LLC t526 S Church Street,Mail Code Eel3k, q
Charlotte,NO 282011 has requested renewal of permit NCS0005W for the 597 of the General Statutes of North Carolina and was a
Mayo steam Electric Power Plant in Person County.This facility discharges
to Bowes Branch In the Roanoke River Basin. qualified newspaper p per within the meaningof Section 1-597
Interested persons may visit DEMLR at 512 N.Salisbury Street, Raleigh,NC ; of the General Statutes of North Carolina,and that as
27604 m review information on file.Additional Infomaation on NPDES penults such he or she makes this affidavit:and is familiar with
and this notice may be found on our websle:hlpsWcara nc.gov/abouVdivi-
sionsienergy-mineml-and-land-resources/stormwater/stormwater-program/ the books,files and business of said corporation and by
stormwater-public-notices.or bycontaciingBnanna Young atbrlanna.young®rleq.ncgov or 919-707-3647. reference to the files of said publication the attached
IPLO127081 ; advertisement for NC DENR ENGERGY MINERAL&LAND
Jun 16 20M RESOURCES was inserted in the aforesaid newspaper on
dates as follows:
1 insertion(s)published on:
06/16/23
r
RECEIVED
certify ordeclare)under penalty o perjury that t e
foregoing is true and correct.
DEMLR-Stormwater PrograM
Notary Public inand for the stateo Texas,residing in
Dallas County
STEPHANIE HATCH ER
My Notary ID#133534406
E10res January 14,2026
Extra charge for lost or du pl late affidavits..
Legal doament please do not destroyl

Young, Brianna A
From: Guyer, Shawn
Sent: Monday,July 3, 2023 12:45 PM
To: Young, Brianna A
Subject: RE: Draft NPDES stormwater permits NCS000606 and NCS000580
Brianna,
NCS000606:
The PWS Section concurs with the issuance of this permit provided the facility is operated and maintained
properly,the stated effluent limits are met prior to discharge, and the discharge does not contravene the
designated water quality standards.
NCS000580:
The PWS Section concurs with the issuance of this permit provided the facility is operated and maintained
properly,the stated effluent limits are met prior to discharge, and the discharge does not contravene the
designated water quality standards.
Shawn
From:Young, Brianna A<[e-mail]>
Sent: Wednesday,June 14, 2023 8:35 AM
To: Guyer, Shawn <[e-mail]>
Subject: Draft NPDES stormwater permits NCS000606 and NCS000580
Good morning,
The draft permits for the Harris Nuclear Power Plant(NCS000606) and Mayo Steam Electric Plant(NCS00080) have been
submitted for public notice.These facilities discharges to class WS-V waters. Please provide any comments on this draft
permit by July 17, 2023.
Thank you,
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)PLEASE NOTE NEW EMAIL ADDRESS
**DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th. Employee email addresses may look
different, but email performance will not be impacted.
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
1

Public Records Law and may be disclosed to third parties.
The Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Please
check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email.
Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized
state official.
2

Young, Brianna A
From: Tollie, Lori White <[e-mail]>
Sent: Tuesday, July 11, 2023 7:44 AM
To: Young, Brianna A
Cc: Wilson, Leanne; Slade, Joseph Heath
Subject: RE: [EXTERNAL] Draft NPDES stormwater permit NCS000580
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Hi Brianna,
The Mayo Steam Station team met yesterday and we will have no further comments to submit in support of ISW
renewal.Thank you for the opportunity to review.
Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent: Friday,July 7, 2023 10:13 AM
To:Tollie, Lori White<[e-mail]>
Cc:Wilson, Leanne<[e-mail]>; Slade,Joseph Heath <[e-mail]>
Subject: RE: [EXTERNAL] Draft NPDES stormwater permit NCS000580
Good morning Lori,
I apologize for the delayed response. I reviewed the previous permit and that footnote was inadvertently left off the
draft permit. I can make the correction to add the footnote back in before a decision is made on the final permit.
Thank you,
Brianna Young, MS(she/her)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)PLEASE NOTE NEW EMAIL ADDRESS
**DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th. Employee email addresses may look
different, but email performance will not be impacted.
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
1

Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
The Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Please
check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email.
From:Tollie, Lori White<[e-mail]>
Sent:Thursday,June 29, 2023 9:51 AM
To:Young, Brianna A<[e-mail]>
Cc:Wilson, Leanne<[e-mail]>; Slade,Joseph Heath <[e-mail]>
Subject: RE: [EXTERNAL] Draft NPDES stormwater permit NCS000580
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Hi Brianna,
We have reviewed the Mayo Draft ISW and have one question. In the previous permit after 2 non detects for PCBs we
could discontinue monitoring. Is that still the process?
Thanks so much.
Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent:Wednesday,June 14, 2023 8:36 AM
To: Bednarcik,Jessica L<[e-mail]>
Cc:Tollie, Lori White<[e-mail]>;Winston, Cynthia C<[e-mail]>;
Wilson, Leanne<[e-mail]>; Slade,Joseph Heath <[e-mail]>
Subject: [EXTERNAL] Draft NPDES stormwater permit NCS000580
CAUTION! STOP. • expecting
and spelling correct? Does the content make sense? Can you verify the sender? If suspicious report it, then do
not click links, open attachments or enter your ID or password.
Good morning,
The draft stormwater permit for the Mayo Steam Electric Plant(NCS000580) has been submitted for public notice.A
hard copy of this draft permit will be mailed to Jessica Bednarcik. Please provide any comments on this draft permit by
July 17, 2023.
Thank you,
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
2

NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)PLEASE NOTE NEW EMAIL ADDRESS
**DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th. Employee email addresses may look
different, but email performance will not be impacted.
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, INC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
The Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Please
check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email.
Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized
state official.
3

Young, Brianna A
From: Young, Brianna A
Sent: Friday, July 7, 2023 10:13 AM
To: Tollie, Lori White
Cc: Wilson, Leanne; Slade, Joseph Heath
Subject: RE: [EXTERNAL] Draft NPDES stormwater permit NCS000580
Good morning Lori,
I apologize for the delayed response. I reviewed the previous permit and that footnote was inadvertently left off the
draft permit. I can make the correction to add the footnote back in before a decision is made on the final permit.
Thank you,
Brianna Young, MS(she/her)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)PLEASE NOTE NEW EMAIL ADDRESS
**DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th. Employee email addresses may look
different, but email performance will not be impacted.
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
The Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Please
check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email.
From:Tollie, Lori White<[e-mail]>
Sent:Thursday,June 29, 2023 9:51 AM
To:Young, Brianna A<[e-mail]>
Cc:Wilson, Leanne<[e-mail]>; Slade,Joseph Heath <[e-mail]>
Subject: RE: [EXTERNAL] Draft NPDES stormwater permit NCS000580
CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the Report Message
button located on your Outlook menu bar on the Home tab.
Hi Brianna,
We have reviewed the Mayo Draft ISW and have one question. In the previous permit after 2 non detects for PCBs we
could discontinue monitoring. Is that still the process?
Thanks so much.
i

Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent:Wednesday,June 14, 2023 8:36 AM
To: Bednarcik,Jessica L<Jessica.Bed [e-mail]>
Cc:Tollie, Lori White<[e-mail]>;Winston, Cynthia C<[e-mail]>;
Wilson, Leanne<[e-mail]>;Slade,Joseph Heath <[e-mail]>
Subject: [EXTERNAL] Draft NPDES stormwater permit NCS000580
CAUTION! STOP. • expecting
and spelling correct? Does the content make sense? Can you verify the sender? If suspicious report it, then do
not click links, open attachments or enter your ID or password.
Good morning,
The draft stormwater permit for the Mayo Steam Electric Plant(NCS000580) has been submitted for public notice.A
hard copy of this draft permit will be mailed to Jessica Bednarcik. Please provide any comments on this draft permit by
July 17, 2023.
Thank you,
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)PLEASE NOTE NEW EMAIL ADDRESS
**DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th. Employee email addresses may look
different but email performance will not be impacted.
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
The Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Please
check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email.
Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized
state official.
2

Compliance Inspection Report
Permit:NCS000580 Effective: 03/21/19 Expiration: 12/31/21 Owner: Duke Energy Progress LLC
SOC: Effective: Expiration: Facility: Mayo Steam Electric Power Plant
County: Person 10660 Boston Rd
Region: Raleigh
Roxboro NC 27573
Contact Person:Tom Copolo Title: Plant Manager Phone: [phone]
Directions to Facility:
System Classifications: SWNC,
Primary ORC: Certification: Phone:
Secondary ORC(s):
On-Site Representative(s):
Related Permits:
Inspection Date: 04/26/2023 Entry Time 10:OOAM Exit Time: 12:15PM
Primary Inspector:Thaddeus W Valentine Phone:
Secondary Inspector(s):
Reason for Inspection: Routine Inspection Type: Compliance Evaluation
Permit Inspection Type: Stormwater Discharge, Individual
Facility Status: Compliant ❑ Not Compliant
Question Areas:
Storm Water
(See attachment summary)
Page 1 of 4

Permit: NCS000580 Owner-Facility:Duke Energy Progress LLC
Inspection Date: 04/26/2023 Inspection Type:Compliance Evaluation Reason for Visit: Routine
Inspection Summary:
I meet with Leanne Wilson,Lori Tollie and others at the Mayo facility for Duke Energy to perform a stormwater complaince
inspection. During this inspection I found that the permittee keeps very extensive and detailed records and documentation to
meet the stormwater permit requirements. There were just a couple areas that I would request that specific attention be
paid, to better capture and prevent any stormwater pollution issues. The site map was included with much of the information
required, there were areas that should have been identified, such as the chlorine building, that were not shown on the map.
Any areas with the potential for pollution to stormwater,along with any other areas required by the permit,should be shown
on the map.
Site inspections are done regularly, but there are some site specific areas with the potential to pollute stormwater that
should be added to the checklist such as the chlorine building. Example: There are poly totes without secondary
containment under the shed side of the building that have the potential to leak, spill or to crack and cause a spill that would
be exposed to stormwater. There were chemicals stored next to the rollup door that could be a potential stormwater
pollutant that should be stored in a safe location that would have been identified as an issue if that area was part of a
checklist. Please provide checklist for all site specific areas with the potential to be a stormwater pollutant source.
The request to combine the two stormwater permits for the monilift NCG120101 and the individual stormwater permit
NCS000580 has been approved. The number system has been altered to reflect the requested removal of alphanumeric
numbering as well as making the requested changes to the numbering for stormwater permit NCS000580. Outfall 002 is now
007 for that permit outfall.These changes will come effective at the renewal of your stormwater permit NCS000580. Also, at
the same time as the renewal stormwater permit NCG120101 will be rescinded.
05/04/2023 THIS REPORT IS NOT COMPLETE. wAITUNG ON A RESPONSE FROM THE CENTRAL OFFICE ABOUT
CHANGING OUTFALL NUMBERING
Page 2 of 4

Permit: NCS000580 Owner-Facility:Duke Energy Progress LLC
Inspection Date: 04/26/2023 Inspection Type:Compliance Evaluation Reason for Visit: Routine
Stormwater Pollution Prevention Plan Yes No NA NE
Does the site have a Stormwater Pollution Prevention Plan? ❑ ❑ ❑
#Does the Plan include a General Location (USGS) map? ❑ ❑ ❑
#Does the Plan include a"Narrative Description of Practices"? ❑ ❑ ❑
#Does the Plan include a detailed site map including outfall locations and drainage areas? ❑ ❑ ❑
#Does the Plan include a list of significant spills occurring during the past 3 years? ❑ ❑ ❑
#Has the facility evaluated feasible alternatives to current practices? ❑ ❑ ❑
#Does the facility provide all necessary secondary containment? ❑ ❑ ❑
#Does the Plan include a BMP summary? ❑ ❑ ❑
#Does the Plan include a Spill Prevention and Response Plan (SPRP)? ❑ ❑ ❑
#Does the Plan include a Preventative Maintenance and Good Housekeeping Plan? ❑ ❑ ❑
#Does the facility provide and document Employee Training? 0 ❑ ❑ ❑
#Does the Plan include a list of Responsible Party(s)? 0 ❑ ❑ ❑
# Is the Plan reviewed and updated annually? 0 ❑ ❑ ❑
#Does the Plan include a Stormwater Facility Inspection Program? ❑ 0 ❑ ❑
Has the Stormwater Pollution Prevention Plan been implemented? 0 ❑ ❑ ❑
Comment: The plan has a detailed site map but I have asked that additional areas of thesite be added to
the map such as the chlorine shop and any other activity areas such as that along with the
outfall locations.
Stomrwater facility inspections were provided but I recommend that inspection checklist for
specific areas such as the Chlorine building be added to the checklists as a site specific
checklist area, along with any other areas that could potentially be a stormwater pollution
discharge area.
A list of significant spills should be added to the SWPPP
Qualitative Monitoring Yes No NA NE
Has the facility conducted its Qualitative Monitoring? 0 ❑ ❑ ❑
Comment: Provided
Analytical Monitoring Yes No NA NE
Has the facility conducted its Analytical monitoring? 0 ❑ ❑ ❑
#Has the facility conducted its Analytical monitoring from Vehicle Maintenance areas? 0 ❑ ❑ ❑
Comment: Provided
Permit and Outfalls
Yes No NA NE
# Is a copy of the Permit and the Certificate of Coverage available at the site? ❑ ❑ ❑
#Were all outfalls observed during the inspection? ❑ ❑ ❑
# If the facility has representative outfall status, is it properly documented by the Division? ❑ ❑ ❑
#Has the facility evaluated all illicit(non stormwater)discharges? 0 ❑ ❑ ❑
Comment: The outfalls were observed and alternate numbering was requested
Page 3 of 4

Permit: NCS000580 Owner-Facility:Duke Energy Progress LLC
Inspection Date: 04/26/2023 Inspection Type:Compliance Evaluation Reason for Visit: Routine
Page 4 of 4

Young, Brianna A
From: Cook, Brittany
Sent: Thursday, May 4, 2023 11:06 AM
To: Young, Brianna A; Valentine, Thad
Subject: RE: NCS000580/NCG120101 Combination
Thanks Brianna,
Once the MAYO site has their permit issued, I will rescind the NCG12.
Mrs.Brittany Cook
General Industrial Stormwater Permit Coordinator
Stormwater Program,Division of Energy,Mineral,and Land Resources
N.C.Department of Environmental Quality
Phone: [phone]
DEQ is updating its email addresses to @deq.nc.gov in phases from May 1st to June 9th.
Employee email addresses may look different, but email performance will not be impacted.
From:Young, Brianna A<[e-mail]>
Sent:Thursday, May 4, 2023 11:03 AM
To:Valentine,Thad <[e-mail]>
Cc: Cook, Brittany<[e-mail]>
Subject: RE: NCS000580/NCG120101 Combination
The monofill outfalls were already added in the draft permit. See below from my permit fact sheet. I can renumber the
outfalls so none have the "a" designation (this is how Duke identified them in the application).
• Outfalls SW001, SW002a, and SWO03 added from NCG210101 per permittee's request
o New monitoring requirements assigned to each outfall (different from what NCG210101
required)
Outfall SWO01: Monofill
Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SWO02: Discharge to Bowes Branch
Drainage area includes the railroad corridor for coal delivery, a stockpile area and equipment storage for an active
construction project, a temporary construction trailer, a permanent facility warehouse, a permanent facility material
stockpile, and equipment staging areas.
Outfall SW002a: Monofill
Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SWO03: Monofill

Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SW006a: Cooling Tower
Discharge area includes mobile equipment utilization. Potential pollutants include: Petroleum and herbicides.
Outfall SWO10: Access Road
Drainage area includes vehicular traffic from flue gas desulfurization system and ash handling system.This will include
trucks hauling conditioned ash (ash mixed with water to minimize dust), limestone for injection into the stack as part of
the flue gas desulfurization system, and gypsum (by-product of the FGD process).
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19,the Department of Environmental Quality has adjusted
operations to protect the health and safety of the staff and public. Please check with the appropriate staff before visiting our offices,
as we may be able to handle your requests by phone or email.We appreciate your patience as we continue to serve the public
during this challenging time.
From:Valentine,Thad <[e-mail]>
Sent: Wednesday, May 3, 2023 2:21 PM
To:Young, Brianna A<[e-mail]>
Cc: Cook, Brittany<[e-mail]>
Subject: NCS000580/NCG120101 Combination
Brianna
The facility contact for the (Mayo) Duke Energy plant NCS000580 have asked for the previously requested combination
of permits NCS000580 & NCG120101, discussed with Bethany in 2018, be initiated in this renewal. I have attached the
request letter that was signed by Bethany for review. Duke Energy(Mayo) Plant would also like to change SDO-002 to
007 on the NCS000580 permit site due to having 3)002 SDO's at the facility.They would like to combine permit
NCG120101-SDO-001,002 &003 with permit NCS000580-SDO-006, 007 (presently 002) &010 for a combined Individual
permit NCS000580 with SDO-002,003, 003, 006,007 &010.
I was a bit confused with the sample requirements for the two permits, but they are close to one another and may only
require an additional one sample parameter be added to capture all sample requirement for both.
Fecal Coliform was removed by our office in 2018 and that document is available in Laserfiche.
If all that is acceptable, I will draft the inspection report in BIMs to reflect that with a couple other recommendations for
your review for the renewal.
Thad Valentine
Environmental Senior Specialist— RRO
Division of Energy, Mineral, and Land Resources— Land Quality Section
Department of Environmental Quality
2

919 791 4220 office
thad.valentine(c�ncdenr.gov
1628 Mail Service Center, Raleigh, North Carolina 27699
3

d STATt q
•�R—
VUNI
ROY COOPER NORTH CAROLINA
Governor Environmental Quality
MICHAEL S.REGAN
Secretary
WILLIAM E.(TOBY)VINSONJR.
Interim Der Iry
November 6, 2018
Mr. Tom Copolo
Station Manager
Duke Energy Progress, LLC
10660 Boston Road
Roxboro, NC 27574
Subject: General Permit No. NCG120000 -Renewal
Mayo Steam Plant Monofill
COC No. NCG120101
f,E ` I D Person County
Dear Mr. Copolo: 1 I ��I~11r :
Please see the attached new�e4640 ICoverage(COC) No.NCG120101 for renewed coverage
under Stormwater General Permit NCG120000 for this facility. This permit is reissued pursuant to
the requirements of North Carolina General Statute 143-215.1 and the Memorandum of Agreement
between the state of North Carolina and the U.S. Environmental Protection Agency, dated October
15, 2007(or as subsequently amended.)
We received the company's request for clarification on this COC renewal on September 13, 2018.
Renewed coverage under this General Permit is granted with the condition that the permittee
performs additional sampling requirements as outlined in the amended conditions to the COC. These
requirements are based on the material landfilled at this site. This COC requires you to sample each
SDO semi-annually for arsenic,selenium,boron,conductivity,and pH. This COC also does not
require fecal coliform monitoring. These monitoring parameters are based on the coal combustion
residual material stored, and on monitoring results from 2014 and 2017 that were submitted with the
request.
Duke Energy indicated it would request a modification to NPDES Industrial Permit No. NCS000580
for Mayo Electric Generating Plant to include stormwater discharges from the Mayo Monofill. The
Stormwater Program agrees a modification to that individual permit to include those discharges is
preferable to continued coverage under this General Permit, Because General Permit NCG 120000
expires on May 31, 2021—six months prior to the expiration of Mayo Plant's individual permit—our
staff can coordinate a permit modification with the renewal of the individual permit.
DENORTH CPAOLN4
fwru.si of iwrusu prRr
North Carolina Department of Environmental Quality I Division of Energy.Mineral and Land Resources
512 North$alishury Street 1 1612 Mail Service Center I Raleigh.North Carolina 27699 1612
919.707.9200

The permittee is required to apply for renewal no later than 180 days(six months) before the
expiration of the Plant's individual permit NCS000580(per Part III., Section B.): by July 1, 2021 in
this case. Because that date occurs after the General Permit expires, we advise the company to
request the modification and apply for renewal of NCS000580 by December 31,2020. This date will
give Program staff the opportunity to renew and issue the permit before the COC for the Monofill
expires.
The General Permit authorizes discharges of stormwater, and it specifies your obligations with
respect to discharge controls, management, monitoring,and record keeping. Please review the new
permit to familiarize yourself with all changes in the reissued permit. Your facility has six(6)months
from receipt of the permit to update your Stormwater Pollution Prevention Plan(SPPP)to reflect any
new permit requirements. Enclosed is a copy of the NCG 120000 General Permit.
When does electronic DMR(eDMR)reporting start,and does it affect this permit?
Because this COC requires analytical monitoring, eDMR will affect you. We are working toward on-
boarding permittees with NPDES stormwater permits into the DEQ's eDMR system next
year. Permittees will receive notification when our eDMR system is ready for permit-holders to
register and begin reporting monitoring data electronically.
Your coverage under the General Permit is transferable only through the specific action of
DEMLR. This permit does not affect the legal requirements to obtain other permits which may be
required by the N.C. Department of Environmental Quality(DEQ),nor does it relieve the permittee
from responsibility for compliance with any other applicable federal, state,or local law,rule,
standard,ordinance,order,judgment,or decree.
If you have any questions concerning this permit, please contact Bethany Georgoulias at telephone
number(919)707-3641 or by email bethany.georpoulias a.ncdenr.aov.
Sincerely,
for William E. (Toby)Vinson,Jr.,P.E.,CPM, Interim Director
Division of Energy, Mineral,and Land Resources
cc: Raleigh Regional Office/Bill Denton
Stormwater Program Files
Lori Tollie/Duke Energy(via e-mail)
DWR Central Files
North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources
512 North Salisbury Street 1 1612 Mail Service Center Raleigh North Carolina 27699.1612
919.707.9200

STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF ENERGY, MINERAL,AND LAND RESOURCES
FjENERAL PERMIT NO.NCG120000
C_ERTIFICAU_OF COVERAGE No. NCQ20101
STORMWATER DISCHARGES
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision 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, and the North
Carolina Administrative Code in NCAC 15A 02H .0114(b)(1),as amended,
Duke Energy Progress, Inc.
is hereby authorized to discharge stormwater from a facility located at
Mayo Steam Electric Plant Monofill
10660 Boston Road
Roxboro
Person County
to receiving waters designated as Bowes Branch, a class C water in the Roanoke River
Basin, in accordance with the effluent limitations, monitoring requirements, and other
conditions set forth in Parts 1, 11, 111, and IV of General Permit No. NCG120000 as attached,
and as amended in pages 2-3 of this Certificate of Coverage.
Amgnded conditions
1. This Certificate of Coverage is an enforceable part of the permit.
2. In accordance with 1SA NCAC 02H .0114(b)(1), the monitoring program in Part it
Section B Table 1 Analytical Monitoring Requirements of this permit is amended
as follows:

Table 1 Analytical Monitoring Re uirements
Discharge Measurement Frequency)TGrab
le Sample
Characteristics Units 2 Location3
Chemical Oxygen Demand m 1 semi-annual SDO
Fecal Coliform # per 100 ml not required N/A
Total Suspended Solids mg/1 semi-annual Grab SDO
Arsenic (As)5 mg/I semi-annual Grab SDO
Selenium (Se)5 mg/I semi-annual Grab SDO
Boron B 5 mg/I semi-annual Grab SDO
}{5 S.U. semi-annual Grab SDO
Conductivity S m semi-annual Grab SDO
Total Rainfa114 inches semi-annual Rain gauge
Footnotes:
1 Measurement Frequency: Twice peryear,during a measureable storm event.
z Sample collection must begin within the first 30 minutes of discharge and continue to all outfalls until
completed.
3 Sample Location: Samples shall be collected at each stormwater discharge outfall(SDO) unless
representative outfall status(ROS)has been granted by NC Division of Energy,Mineral,and Land
Resources(DEMLR). A copy of the DEMLR letter granting ROS must be kept on site. DEMLR's ROS letter
remains in effect through the subsequent reissuance of this permit and as long as the pertinent site
conditions and operations remain unchanged,unless the ROS letter provides for other conditions or
duration.
4 For each sampled measureable storm event the total precipitation must be recorded from an on-site rain
gauge.(Where isolated sites are unmanned for extended periods,a local rain gauge reading may be
substituted for an on-site gauge,upon prior DEMLR written approval.)
5 No benchmark applies for these parameters. However,levels above 0.34 mg/I As,0.056 mg/l Se,or
outside a pH range of 6.0-9.0 S.0 should be noted on the Stormwater Data Monitoring Report(SDMR)
submitted to NC DEQ.
This Certificate of Coverage shall become effective November 1, 2018.
This Certificate of Coverage shall rema. in effect for the duration of the General Permit.
for William E. (Toby) Vinson,Jr., P.E., CPM
Interim Director, Division of Energy, Mineral, and Land Resources
By the Authority of the Environmental Management Commission
v 2 1COC No. NCG120101
effective November 1, 2018

Young, Brianna A
From: Valentine, Thad
Sent: Thursday, May 4, 2023 11:47 AM
To: Young, Brianna A
Cc: Lawyer, Mike; Cook, Brittany
Subject: RE: NOI Inspections
That is all correct except for SWO02 which has become a much smaller area of drainage. It now captures a very small
drainage area that includes an access road and the railroad corridor.The outfall numbering scheme that was discussed
at the inspection included removing the alphabetical numbering and changing outfall SW002:designated as Discharge to
Bowes Branch-to out 007. Doing that would simplify the numbering by dropping the (a) designations and replace one of
the three 002 designations they have (two stormwater and one wastewater)
That gives them 001, 002 &003 at the monofil (new individual permit) and 006,007&010 for the individual stormwater
permit making it a bit simpler. Is that acceptable
Thad Valentine
Environmental Senior Specialist— RRO
Division of Energy, Mineral, and Land Resources— Land Quality Section
Department of Environmental Quality
919 791 4220 office
thad.valentine(@ncdenr.gov
1628 Mail Service Center, Raleigh, North Carolina 27699
From:Young, Brianna A<[e-mail]>
Sent:Thursday, May 4, 2023 11:01 AM
To:Valentine,Thad <[e-mail]>
Cc: Lawyer, Mike <[e-mail]>; Cook, Brittany<[e-mail]>
Subject: RE: NOI Inspections
For Mayo (NCS00580),the monofill outfalls were already added in the draft permit. See below from my permit fact
sheet. I can renumber the outfalls so none have the "a" designation (this is how Duke identified them in the application).
• Outfalls SW001, SW002a, and SWO03 added from NCG210101 per permittee's request
o New monitoring requirements assigned to each outfall (different from what NCG210101
required)
Outfall SWO01: Monofill
Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SWO02: Discharge to Bowes Branch
Drainage area includes the railroad corridor for coal delivery, a stockpile area and equipment storage for an active
construction project, a temporary construction trailer, a permanent facility warehouse, a permanent facility material
stockpile, and equipment staging areas.
Outfall SW002a: Monofill
1

Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SWO03: Monofill
Drainage area includes trucks hauling conditioned ash (ash mixed with water or brine to minimize dust), off specification
gypsum, and other approved monofill waste.
Outfall SW006a: Cooling Tower
Discharge area includes mobile equipment utilization. Potential pollutants include: Petroleum and herbicides.
Outfall SWO10: Access Road
Drainage area includes vehicular traffic from flue gas desulfurization system and ash handling system.This will include
trucks hauling conditioned ash (ash mixed with water to minimize dust), limestone for injection into the stack as part of
the flue gas desulfurization system, and gypsum (by-product of the FGD process).
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Permitting Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19,the Department of Environmental Quality has adjusted
operations to protect the health and safety of the staff and public. Please check with the appropriate staff before visiting our offices,
as we may be able to handle your requests by phone or email.We appreciate your patience as we continue to serve the public
during this challenging time.
From:Valentine,Thad <[e-mail]>
Sent:Thursday, May 4, 2023 10:49 AM
To:Young, Brianna A<[e-mail]>
Cc: Lawyer, Mike <[e-mail]>; Cook, Brittany<[e-mail]>
Subject: NOI Inspections
I have the questions asked about the (2) Duke Power sites (NCS000580& NCS000581) I looked at last week that I need
to get an answer on before I can do my reports. I don't want to rush anyone, but just as a reminder of questions I need
answered.
Duke Energy(Mayo) NCS000580:
Can we combine the (2) stormwater permits NCS00581 & NCG120101 into one individual permit and changing (1) outfall
number when combining(Outfall 002 will become out 007 on the individual permit NCS000580)
That would make the numbering of outfall for that combined permit to be 001, 002,003, 006, 007&010 along with a
review of the samples for both permits to ensure that all sample parameters are covered
This is something that Bethany was agreeable with and discussed in a previous correspondence were she advised the
permittee to request at renewal
2

Duke Energy(Semora) NCS000581:
Can that permit be rescinded.The question is, do the rail cars that travel by that yard with gypsum, limestone and coal
establish enough of a potential problem for the permit to remain in place. I provided the sample data from the stream
outlet that runs between the yard in question and the railroad tracks in question from 2017-2020 for comparison with
benchmark values to assist with that assessment
I have plenty to do until a call on those questions can be made and I will be available for any additional questions.
Thanks for your help
Thad Valentine
Environmental Senior Specialist— RRO
Division of Energy, Mineral, and Land Resources— Land Quality Section
Department of Environmental Quality
919 791 4220 office
thad.valentineC�ncdenr.gov
1628 Mail Service Center, Raleigh, North Carolina 27699
3

Young, Brianna A
From: Tollie, Lori White <[e-mail]>
Sent: Wednesday,August 10, 2022 1:48 PM
To: Young, Brianna A; Bednarcik,Jessica L
Cc: Winston, Cynthia C;Wilson, Leanne; Slade,Joseph Heath
Subject: RE: [EXTERNAL] Mayo Electric Generating Plant (NCS000580) stormwater permit
application
Attachments: Summary of Analytical Monitoring NCS000580 Permit Renewal.xlsx; Mayo NCG12 Data
Table 2022.xlsx; NCG120101_Special Renewal COC Issuance_20181106.pdf; Mayo Outfall
Coordinates 2022.xlsx; Mayo Drainage Area Descriptions 2022.docx
CAUTION: External email. Do not click links or open attachments unless you verify.Send all suspicious email as an attachment to
Report Spam.
Brianna,
I have verified that the information in the renewal application is correct and current.There have been no substantial
operational changes since the initial renewal application was submitted and I have attached the additional information
you have requested. Please let me know if you need anything further or have any questions.
Thank you.
Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent: Friday,August 5, 2022 8:51 AM
To: Bednarcik,Jessica L<Jessica.Bed [e-mail]>
Cc:Tollie, Lori White<[e-mail]>
Subject: [EXTERNAL] Mayo Electric Generating Plant (NCS000580) stormwater permit application
CAUTION! STOP. • expecting
and spelling correct? Does the content make sense? Can you verify the sender? If suspicious report it, then do
not click links, open attachments or enter your ID or password.
Good morning,
The Division of Energy, Mineral, and Land Resources (DEMLR) Stormwater Permitting Program
acknowledges receipt of your renewal application for coverage under NPDES Permit Number NCS000580 on
December 30, 2020. Please continue to comply with all conditions and monitoring requirements in your current
NPDES stormwater permit. Please let me know if you have any questions in the interim.
1

I am working on renewing the individual stormwater permit for the Mayo Electric Generating Plant
(NCS000580). I need additional information in order to 1) confirm that the information I have is correct and 2)
make sure the permit adequately serves the needs of the facility. Please provide the following for both
NCS000580 as well as Certificate of Coverage (COC)NCG120101:
• Confirmation on the number of outfalls and coordinates;
• Description of industrial activity in each drainage area;
• An electronic spreadsheet summarizing all of the monitoring data that has been collected since the
effective date of the current permit;
• Verification that the information in the renewal application is still complete and correct; and
• An explanation of any operational changes since the renewal application was submitted.
Enter your stormwater permit number into the Stormwater Permit Summary Report and you will see a form that
includes the address of the facility, contact information for the permit, and the regulated stormwater outfall(s)
for the facility. Please review the facility information to make sure it is correct. Information can be updated
using the links provided below, where applicable:
• Facility/Company name or ownership: Name/Ownership Change Form
• Owner Affiliation (Legally responsible person; i.e., someone with the company who is designated to
represent the company per signatory requirements or another authorized representative): Permit Contact
Update Request Form
• Delegation of Signature Authority (DOSA): Permit Contact Update Request Form
• Billing contact: Permit Contact Update Request Form
• Permit contact: Permit Contact Update Request Form
• Facility contact: Permit Contact Update Request Form
• Facility address only: Email Bethany og ulias
• Stormwater outfall information: Email Bethany Georgoulias
• Visit the eDMR Six Steps website and complete Steps 1 and 2.
• Pay outstanding permit fees: Stormwater ePayment website
Once I have the above listed information, I can continue my review. You will receive a draft permit for a 30-day
comment period. During this time we will be able to address any comments or concerns you have. During the
same 30-day period, the draft will be sent to a Regional Office staff member for review as well as out to public
notice. Once all comments and concerns are addressed, you may be issued a final permit.
Please contact me if you have any questions.
Thank you,
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)
919-707-3647(office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address:512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
2

Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19,the Department of Environmental Quality has adjusted
operations to protect the health and safety of the staff and public. Many employees are working remotely or are on staggered shifts.
Please check with the appropriate staff before visiting our offices,as we may be able to handle your requests by phone or email.We
appreciate your patience as we continue to serve the public during this challenging time.
3

Drainage Area Descriptions
Outfall 010 -Access Road
With the addition of a flue gas desulfurization system and ash handling system at the site
there will be routine vehicular traffic on the site access road. This will include trucks
hauling conditioned ash(ash mixed with water to minimize dust), limestone for injection
into the stack as part of the flue gas desulfurization system and gypsum(by-product of
the FGD process). All trucks will be covered and directed to a truck wash area before
leaving the site via the access road.
Outfall 001,002, 003 —Monofill
Trucks hauling conditioned ash(ash mixed with water or brine to minimize dust), off
specification gypsum, and other approved monfill waste.
Outfall 006a—Cooling Tower Area
Due mobile equipment utilization there is a potential for petroleum release. On rare
occasions herbicides are used for ground maintenance at the cooling towers.
Outfall 002—Discharge to Bowes Branch
The industrial activity and storage in the drainage area includes the railroad corridor for
coal delivery to Mayo Steam Station, a stockpile area and equipment storage for an active
construction project, a temporary construction trailer, a permanent facility warehouse, a
permanent facility material stockpile, and equipment staging areas.

CDC NCG120101
Facilty Name Mayo Steam Plant Monofill
Discharge to Bowes Branch
Outfall 24 hour Total Total Total Total
No. Date Collected rainfall COD TSS As Se B pH Conductivity Mn TI Fecal Coliform Chlorides Fluoride Sulfate Hardness
Units inches mg/L mg/L mg/L mg/L mg/L S/m mg/L mg/L mg/L mg/L mg/L mg/L
Benchmarks-- 120 mg/L 100 mg/L 6.0 to 9.0 1000 counts
_> Mayo Lab/Pace Lab per 100 mL
1 12/16/2014 0.12 8 3.1 <0.0005 <0.0005 <0.025 6.92 0.00628 <0.0005 4.1 1.3 <0.25 2.6 15.4
1 6/3/2015 3.3 23.0 75.9 0.0016 0.00044 0.0364 7.33 0.01031 0.077 <0.00005 3.1
1 10/28/2015 1.3 <12.5 4.9 0.00083 0.00028 <0.0250 8.12 0.007384/0.00836 54.7
1 5/17/2016 0.90 27.0 15.5 0.0025 0.00094 0.396 6.49 0.00866 2420
1 12/16/2016 0.71 13 7.7 0.0005 <0.00031 0.674 6.96 0.0444 89
1 6/19/2017 0.43 15 12.5 <0.004 <0.031 <0.056 7.13 0.0098 <0.0015 112 3.5 0.089 2.1 32.3
1 11/9/2017 0.95 <12.5 23.9 0.00075 0.00084 0.0363 7.41 0.00491 520
1 4/24/2018 1.02 14 13.6 0.0007 0.00027 0.261 6.96 0.0154 117
1 2018
1 2019
1
1 2020
1 10/12/2020 2.78 22 8.3 <.001 <.001 <.05 6.85 0.00682
1 6/4/2021 0.48 <20 12 <0.001 <.001 <.05 6.47 0.00493
1 5/24/2022 1.91 26.2 62 <0.001 <.001 <0.05 6.59 0.00569
1
2 12/29/2014 0.47 310 149 0.0011 0.00055 <0.025 7.38 0.00723 <0.0005 15.8 9.5 0.33 4.4 37.9
2 6/3/2015 3.3 23.0 37.6 0.0029 0.00038 0.084 6.97 0.006148 0.0617 <0.00005 3.1
2 10/28/2015 1.3 19.0 12.1 0.00041 0.00017 0.0255 6.93 0.007811/0.00838 69.8
2 5/17/2016 0.90 32 13 0.00066 <0.00031 0.0304 6.62 0.00269 1 2420
2 12/16/2016 0.71 28 12.4 0.0007 <0.00031 0.029 7.34 0.007 241
2 6/20/2017 1.53 21 42.5 <0.004 <0.031 <0.056 7.29 0.00702 <0.0015 41500 0.98 0.052 3.7 24.9
2 11/9/2017 0.95 25 3.9 0.00055 <0.00031 0.0333 7.38 0.00063 3800
2 4/24/2018 1.02 31 4.1 0.0005 <0.00017 0.028 7.45 0.0083 179
2 2018
2 2019
2 12/17/2019 0.25 <20.0 9.5 <.001 <.001 <.05 7.4 0.00629
2 2020
2 10/12/2020 2.78 28 3.8 <.001 <.001 <.05 6.95 0.00592
2 6/10/2021 1.04 55.2 11 0.00132 <.001 <.05 6.51 0.00999
2 5/24/2022 1.91 46.6 9 <0.001 <.001 <0.05 6.38 0.00437
2
3 11/17/2014 0.67 39 445 0.0021 0.0015 <0.025 7.55 0.02707 <0.0005 120 26.9 0.51 18.5 103
3 6/3/2015 3.3 30.0 62.5 0.0009 0.00029 0.0335 7.94 0.009131 0.0348 <0.00005 152
3 10/28/2015 1.3 15.0 7 0.0038 0.00044 0.112 7.95 0.020710/0.02400 38.2
3 5/17/2016 0.90 19 1 44.1 0.0042 0.00056 1 0.071 6.66 0.00361 2420
3 12/16/2016 0.71 43 44.8 0.0072 0.00046 0.186 8.09 0.0168 437
3 6/19/2017 0.43 52 24.5 0.0054 <0.031 <0.056 7.76 0.0156 0.0022 12000 5.9 0.055 14.2 44.7
3 11/9/2017 0.95 18 10.7 0.0025 0.00071 0.0493 8.88 0.00994 6000
3 4/24/2018 1.02 21 33.5 0.0049 0.00026 0.146 8.11 0.0116 933
3 2018
3 2019
3 2019
3 2020
3 10/12/2020 2.78 <20 11 0.00149 <.001 <.05 6.99 0.0067
3 6/4/2021 0.48 25 26 0.00412 <.001 0.105 6.94 0.0178
3 5/24/2022 1.91 26.2 114 0.00214 <.001 0.057 6.85 0.00696
3

Outfall 24 hour
No. Date Collected rainfall Sb Ba Be Cd Cr Cu Pb Hg Mo Ni Ag Zn
Units inches mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L
Benchmarks--
1 12/16/2014 0.12 <0.0005 0.0131 <0.00005 <0.00005 0.0012 0.0014 <0.0005 <0.0001 <0.0005 <0.00062 <0.0005 0.0084
2 12/29/2014 0.47 <0.0005 0.0806 0.00026 <0.00005 0.016 0.0235 0.0024 <0.0001 <0.0005 0.01 <0.0005 0.0156
3 11/17/2014 0.67 <0.0005 0.178 0.00074 <0.00005 0.0358 0.0401 0.0054 <0.0001 0.0014 0.0198 <0.0005 0.0812
1 6/19/2017 0.43 <0.010 0.0184 <0.001 <0.005 0.0094 <0.011 <0.009 <0.00007 0.016 <0.044 <0.007 <0.24
2 6/20/2017 1.53 <0.010 0.0211 <0.001 <0.005 0.0126 <0.011 <0.009 <0.00007 <0.011 <0.044 <0.007 <0.24
3 6/19/2017 0.43 <0.010 0.0438 <0.001 <0.005 <0.009 <0.011 <0.009 <0.00007 <0.011 <0.044 <0.007 <0.24
1
2
3
1
2
3
1
2
3
1
2
3

Mayo Steam Station
Outfall Latitude Longitude
002 36.5236 -78.9052
006a 36.5213 -78.8941
010 36.5380 -78.8941
monofill 001 36.5328 -78.9193
002 36.5312 -78.9209
003 36.5357 -78.9254

Summary of Analytical Monitoring Data 2017-2022
Mayo Steam Electric Plant
NPDES Permit No. NCS000580
Stormwater
Outfall Sw 010
Date
Sampled 3/31/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 9/17/2020 3/16/2021 7/8/2021 1/20/2022
Rainfall 0.94 0.95 0.75 1.75 1.21 1.89 2.03 0.8 0.54 0.49 2.61 0.44 2.16 0.41
pH 6.02 6.02 6.15 6.2 6.09 6.18 6.33 6.46 6.39 6.03 6.52 6.08 5.96 6.31
copper 0.0023 0.0056 0.0056 0.0035 0.00492 0.00511 0.0153 0.00514 0.0046 0.0037 0.00601 0.00304 0.00491 0.0026
selenium 0.00039 0.00082 0.00028 <.00031 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
mercury 0.00000803 8.13 0.00000831 0.0000134 0.0000291 0.000021 0.0000416 0.00000464 550 0.0000142 0.00000999 0.0000082 0.00000782 0.00000719
zinc 0.0089 0.0081 0.0177 0.0082 0.019 0.016 0.028 0.005 0.008 0.009 <.005 <0.007 0.01 0.009
tss 10.6 4.1 50.5 17.9 150 89 324 4 15 4.1 6.9 11 71 3.8
oil &grease <5.0 <1.1 <1.1 <1.1 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
Sulfate 6.4
COD 26
Ca 6600
Additonal Priority Pollutant Metals
Stormwater
Outfall Sw 010
Date
Sampled 3/31/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 9/17/2020 3/16/2021 7/8/2021 1/20/2022
Ag <.00007 <.00007 <.00017 <.00007 <.0002 <.0002 <.0002 <.0002 <.0002 0.0002 <.0002 <.0002 <0.0003 <0.0003
As 0.00044 0.00025 0.00054 0.00042 <.001 <.001 0.00129 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Be 0.000035 0.000014 0.000083 0.000082 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cd <.0005 <.0005 0.000045 <.00005 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cr 0.0017 0.00084 0.0051 0.0028 0.00761 0.00534 0.0221 <.001 0.00236 0.00226 0.0017 <.001 0.00414 0.00191
Ni 0.0017 0.00076 0.0024 0.0019 0.0031 0.00259 0.0113 0.00164 0.00196 0.00154 0.00204 <.001 0.00257 0.002
Pb 0.00053 0.00034 0.002 0.0013 0.00316 0.00207 0.00838 <.001 <.001 <.001 <.001 <.001 0.00127 <.001
Sb <.0001 0.00011 0.00015 <.0001 <.0001 <.001 <.005 <.001 <.001 <.001 <.001 <.001 <.001 <.001
TI <.000015 <.000015 <.000028 <.000015 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002
B 0.0222 0.0058 0.0117 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05

Stormwater
Outfall SW 006A
Date
Sampled 5/22/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 7/23/2019 1/14/2020 9/17/2020 3/16/2021 7/8/2021 1/20/2022
Rainfall 0.79 0.95 0.75 1.75 1.21 2.03 0.49 2.61 0.44 2.16
pH 6.21 6.02 6.15 6.43 6.15 6.47 6.41 6.39 6.78 6.15 6.78
copper 0.01 0.0056 0.0081 0.0041 0.00446 0.00459 0.00706 0.00272 0.0032 0.00331 0.00519
selenium 0.056 0.00082 0.00026 <.00031 <.001 <.001 <.001 <.001 <.001 <.001 <.001
mercury 0.00000328 5.45 0.00000471 0.0000099 0.0000181 0.00000855 0.0000136 0.00000276 0.00000342 0.00000247 0.00000831
zinc 0.126 0.0049 0.0237 0.0134 0.02 0.007 0.011 0.007 <0.005 <0.005 0.007
tss 100 4.3 82.5 10 62 5 <2.5 <2.5 <2.5 <2.5 <2.5
oil &grease 3.5 <1.1 <1.1 <1.1 <.5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
Sulfate
COD
Ca
Stormwater
Outfall SWO06A
Date
Sampled 5/22/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 7/23/2019 1/14/2020 9/17/2020 3/16/2021 7/8/2021 1/20/2022
Ag <.00007 <.0007 <.00017 <.00007 <.0002 <.0002 0.0002 <.0002 <.0002 <0.003 <0.003
As 0.00027 0.00023 0.00038 0.00029 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Be <.000010 0.000011 0.000085 0.000048 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cd <.00005 <.00005 0.000045 <.00005 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cr 0.00038 0.00045 0.0058 0.0016 0.00313 <.001 <.001 <.001 <.001 <.001 <.001
Ni 0.00063 0.00093 0.0029 0.0015 0.00194 0.00138 0.00211 <.001 <.001 <.001 <.001
Pb 0.00015 0.00021 0.0024 0.00078 0.00142 <.001 <.001 <.001 <.001 <.001 <.001
Sb 0.00014 <.0001 <.00012 <.0001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
TI <.000015 <.000015 <.000028 <.000015 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002
B <.05 <.05 <.05 <.05 <.05 <.05 <.05

Stormwater
Outfall SW 002
Date
Sampled 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 4/20/2020 9/17/2020 10/29/2020 2/11/2021 7/9/2021 5/24/2022
Rainfall 1.89 2.03 0.8 0.54 0.49 0.52 2.61 0.84 0.94 2.16 1.91
pH 7.05 6.53 7.26 7.38 6.97 6.8 6.51 6.74 7.5 6.9 7.09
copper 0.0568 0.0144 0.0057 0.00342 0.00356 0.00357 0.00242 0.00305 0.00324 0.00398 0.00397
selenium 0.00117 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
mercury 0.0000699 0.0000143 0.00000149 0.00000322 0.0000035 0.0000176 0.00000844 0.00000375 0.00000564 0.00000393 0.00000515
zinc 0.137 0.018 0.012 0.013 0.008 0.006 0.026 <.005 <0.009 0.007 0.006
tss 1300 237 <2.7 9.13 15 24 4.5 <2.5 14 8.8 19.2
oil &grease <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
Sulfate
COD
Ca
Stormwater
Outfall SWO02
Date
Sampled 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 4/20/2020 9/17/2020 10/29/2020 2/11/2021 7/9/2021 5/24/2022
Ag <.0002 <.0002 <.0002 <.0002 0.0002 <0.0002 <.0002 <.0002 <.0002 <.0003 <.0003
As <.005 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Be 0.00101 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cd 0.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cr 0.0602 0.0155 0.00261 0.00168 0.00245 0.00208 0.00105 <.001 0.00157 0.0011 0.00212
Ni 0.0301 0.00718 0.00136 <.001 0.0027 0.00362 0.00174 0.00146 0.00484 0.00174 0.002
Pb 0.0191 0.0038 <.001 <.001 <.001 <.001 <.001 <.00146 <.001 <.001 <.001
Sb <.005 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
TI <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002
B <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05

Young, Brianna A
From: Tollie, Lori White <[e-mail]>
Sent: Wednesday,August 10, 2022 3:59 PM
To: Young, Brianna A; Bednarcik,Jessica L
Cc: Winston, Cynthia C;Wilson, Leanne; Slade,Joseph Heath
Subject: RE: [EXTERNAL] Mayo Electric Generating Plant (NCS000580) stormwater permit
application
CAUTION: External email. Do not click links or open attachments unless you verify.Send all suspicious email as an attachment to
Report Spam.
Brianna,
We have 2 SW outfalls designated as 002. We had requested that the outfall discharging to Bowes Branch be designated
as outfall 002a once the modification was complete.This change would make the reporting a lot easier.Thanks so much.
Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent:Wednesday,August 10, 2022 3:12 PM
To:Tollie, Lori White<[e-mail]>; Bednarcik,Jessica L<Jessica.Bed [e-mail]>
Cc:Winston, Cynthia C<[e-mail]>; Wilson, Leanne<[e-mail]>;
Slade,Joseph Heath <[e-mail]>
Subject: RE: [EXTERNAL] Mayo Electric Generating Plant(NCS000580) stormwater permit application
Lori,
Thank you for providing this information. On quick glance, can you please define which outfall is SWO02 and which is
SW002a? It seems SWO02 is mentioned twice in the drainage area description and outfall coordinate files so I'm not sure
which one is which. I will reach out with any additional questions as I review the files in more depth.
Thank you,
Brianna Young, MS(she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Program
NC DEQ/Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)
919-707-3647 (office)
1

Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19,the Department of Environmental Quality has adjusted
operations to protect the health and safety of the staff and public. Many employees are working remotely or are on staggered shifts.
Please check with the appropriate staff before visiting our offices,as we may be able to handle your requests by phone or email.We
appreciate your patience as we continue to serve the public during this challenging time.
From:Tollie, Lori White<[e-mail]>
Sent: Wednesday,August 10, 2022 1:48 PM
To:Young, Brianna A<[e-mail]>; Bednarcik,Jessica L<[e-mail]>
Cc:Winston, Cynthia C<[e-mail]>; Wilson, Leanne<[e-mail]>;
Slade,Joseph Heath <[e-mail]>
Subject: RE: [EXTERNAL] Mayo Electric Generating Plant(NCS000580) stormwater permit application
CAUTION: External email. Do not click links or open attachments unless you verify.Send all suspicious email as an attachment to
Report Spam.
Brianna,
I have verified that the information in the renewal application is correct and current.There have been no substantial
operational changes since the initial renewal application was submitted and I have attached the additional information
you have requested. Please let me know if you need anything further or have any questions.
Thank you.
Lori W.Tollie
Duke Energy
Permitting&Compliance
500 Utility Drive
Lewisville,NC 27012
Cell: [phone]
Office: [phone]
From:Young, Brianna A<[e-mail]>
Sent: Friday,August 5, 2022 8:51 AM
To: Bednarcik,Jessica L<[e-mail]>
Cc:Tollie, Lori White<[e-mail]>
Subject: [EXTERNAL] Mayo Electric Generating Plant (NCS000580) stormwater permit application
CAUTION! STOP. • expecting
and spelling correct? Does the content make sense? Can you verify the sender? If suspicious report it, then do
not click links, open attachments or enter your ID or password.
Good morning,
The Division of Energy, Mineral, and Land Resources (DEMLR) Stormwater Permitting Program
acknowledges receipt of your renewal application for coverage under NPDES Permit Number NCS000580 on
2

December 30, 2020. Please continue to comply with all conditions and monitoring requirements in your current
NPDES stormwater permit. Please let me know if you have any questions in the interim.
I am working on renewing the individual stormwater permit for the Mayo Electric Generating Plant
(NCS000580). I need additional information in order to 1) confirm that the information I have is correct and 2)
make sure the permit adequately serves the needs of the facility. Please provide the following for both
NCS000580 as well as Certificate of Coverage (COC)NCG120101:
• Confirmation on the number of outfalls and coordinates;
• Description of industrial activity in each drainage area;
• An electronic spreadsheet summarizing all of the monitoring data that has been collected since the
effective date of the current permit;
• Verification that the information in the renewal application is still complete and correct; and
• An explanation of any operational changes since the renewal application was submitted.
Enter your stormwater permit number into the Stormwater Permit Summary Report and you will see a form that
includes the address of the facility, contact information for the permit, and the regulated stormwater outfall(s)
for the facility. Please review the facility information to make sure it is correct. Information can be updated
using the links provided below, where applicable:
• Facility/Company name or ownership: Name/Ownership Change Form
• Owner Affiliation(Legally responsible person; i.e., someone with the company who is designated to
represent the company per signatory requirements or another authorized representative): Permit Contact
Update Request Form
• Delegation of Signature Authority (DOSA): Permit Contact Update Request Form
• Billing contact: Permit Contact Update Request Form
• Permit contact: Permit Contact Update Request Form
• Facility contact: Permit Contact Update Request Form
• Facility address only: Email Bethany og ulias
• Stormwater outfall information: Email Bethany Geor og ulias
• Visit the eDMR Six Steps website and complete Steps 1 and 2.
• Pay outstanding permit fees: Stormwater ePgMent website
Once I have the above listed information, I can continue my review. You will receive a draft permit for a 30-day
comment period. During this time we will be able to address any comments or concerns you have. During the
same 30-day period, the draft will be sent to a Regional Office staff member for review as well as out to public
notice. Once all comments and concerns are addressed,you may be issued a final permit.
Please contact me if you have any questions.
Thank you,
Brianna Young, MS (she/her/hers)
Industrial Individual Permits Coordinator
Stormwater Program
NC DEQ/ Division of Energy, Mineral, and Land Resources (DEMLR)
[e-mail](e-mail preferred)
919-707-3647 (office)
Mailing address: 1612 Mail Service Center, Raleigh, NC 27699-1612
3

Physical address: 512 North Salisbury Street, Raleigh, NC 27604
Email correspondence to and from this address is subject to the North Carolina
Public Records Law and may be disclosed to third parties.
Based on the current guidance to minimize the spread of COVID-19,the Department of Environmental Quality has adjusted
operations to protect the health and safety of the staff and public. Many employees are working remotely or are on staggered shifts.
Please check with the appropriate staff before visiting our offices,as we may be able to handle your requests by phone or email.We
appreciate your patience as we continue to serve the public during this challenging time.
4

Mayo Electric Generating Plant
(•� DUKE Duke Energy Progress
10660 Boston Road
ENERGY, Roxboro,NC 27574
File: Mayo12520-R December 17, 2020
Ms. Suzanne McCoy
NC DEMLR Stormwater Program
1612 Mail Service Center
Raleigh,NC 27699-1612
P-El1��
EIVED
Subject: Duke Energy Progress, LLC.
Mayo Electric Generating Plant DEC 3 0 2020
NPDES Industrial Stormwater Permit NCS000580 DENR-LAND QUALITY
Renewal and Modification Request STORMWATER PERIVIITTING
Dear Ms.McCoy:
Duke Energy Progress,LLC is submitting herewith supplemental information in support of renewing and
modifying NPDES permit No. NCS000580 as well as a major modification.The subject NPDES permit
expires December 31,2021.The requested modification will provide coverage for the three monofill
stormwater outfalls 001,002,and 003.All three of these stormwater outfalls discharge to Bowes Branch,
a class C surface water in the Roanoke River Basin and are currently covered under the NCG 120101
permit. The NCG120101 will expire May 31,2021. Duke Energy requests the renewal and reissuance of
NPDES Permit No.NCS000580 and further requests that the NCG120101 permit be rescinded upon
reissuance of the subject NPDES permit.
Attached is the renewal application and duplicate copies of all supplementary information.
Should you have any questions please contact Ms. Lori Tollie at Lori.Tollie c duke-energy.com or at
(336)-854-4916.
Sincerely,
Tom Co o
General Manger—Mayo Steam Station
Attachments:
Renewal Application
Supplemental Information
Site map from the Stormwater Pollution Prevention Plan
Summary of Analytical Monitoring Results
Summary of Visual Monitoring Results
Significant Site Changes
Certification of Development and Implementation of SPPP
Fish Tissue Monitoring Results
General Permit Renewal Guidance Letter with NCG120101 Results

May Steam Electric Station
Stormwater Permit NCS000580
Individual Permit Application
Supplemental Information

F M_A Permit Coverage
Renewal Application Form
NCDENR National Pollutant Discharge Elimination System NP Permit Number
NC
Stormwater Individual Permit S000580
Please provide your permit number in box in the upper right hand corner, complete the information in the space provided
below and return the completed renewal form along with the required supplemental information to the address indicated.
Owner Information * Address to which permit correspondence will be mailed
Owner/Organization Name: Duke Energy Progress LLC.
Owner Contact: Paul Draovitch -Senior VP EHS, Operations Support&CCP
Mailing Address: PO Box 1006
Charlotte, NC 28201
Phone Number: 980-373-0408
Fax Number:
E-mail address: Paul. [e-mail]
Facility Information
Facility Name: Mayo Steam Electric Power Plant
Facility Physical Address: 10660 Boston Road
Roxboro, NC 27573
Facility Contact: Tom Copolo
Mailing Address: 10660 Boston Road
Roxboro, NC 27573
Phone Number: 336-597-7307
Fax Number:
E-mail address: [e-mail]
Permit Information
Permit Contact: Lori Tollie
Mailing Address: 2500 Fairfax Road
Greensboro, NC 27407
Phone Number: 336-854-4916
Fax Number:
E-mail address: [e-mail]
Discharge Information
Receiving Stream: Mayo Reservoir
Stream Class: WS-V
Basin: Roanoke
Sub-Basin: 03-02-05
Number of Outfalls: 3 outfalls-Outfall 006a, Outfall 010,and Outfall 002
Facility/Activity Changes Please describe below any changes to your facility or activities since issuance of your permit. Attached a
separate sheet if necessary.
No changes have occurred in the drainage areas of the three existing outfalls. Duke Energy would like to add the three stormwater outfalls
from the Mayo Monofill (Outfalls 001, 002, &003)and not renew the NCG120101 permit that the monofill outfalls are currently covered by.
Duke Energy would like to have monofill stormwater outfall 002 changed to outfal 002a to differentiate it from the existing outfall 002 in
the NPDES permit.
CERTIFICATION
I certify that I am familiar with the information contained in the application and that to the best of my knowledge and belief
such information is true 9CWplete and accurate.
Signature Date 1211-7 I ae
l e C &0 1M —Rf_&S-TA-�,oA S
Print or type name of person signing above Title
Please return this completed application form SW Individual Permit Coverage RenewalStormwater Permitting Program
and requested supplemental information to: 1612 Mail Service Center
Raleigh, North Carolina 27699-1612

SUPPLEMENTAL INFORMATION REQUIRED FOR RENEWAL OF INDIVIDUAL
NPDES STORMWATER PERMIT
Two copies of each of the following shall accompany this submittal in order for the application
to be considered complete:
(Do not submit the site Stormwater Pollution Prevention Plan)
Initials
LWT 1. A current Site Map from the Stormwater Pollution Prevention Plan. The location of
industrial activities(including storage of materials,disposal areas, process areas and
loading and unloading areas), drainage structures,drainage areas for each outfall,
building locations and impervious surfaces should be clearly noted.
LWT 2. A summary of Analytical Monitoring results during the term of the existing permit
(if your permit required analytical sampling). Do not submit individual lab reports.
The summary can consist of a table including such items as outfall number,
parameters sampled, lab results, date sampled, and storm event data.
LWT 3. A summary of the Visual Monitoring results. Do not submit individual monitoring
reports. The summary can consist of a table including such items as outfall number,
parameters surveyed, observations, and date monitoring conducted.
LWT 4. A summary of the Best Management Practices utilized at the permitted facility.
Summary should consist of a short narrative description of each BMP's in place at
the facility. If the implementation of any BMP's is planned,please include
information on these BMP's.
LWT 5. A short narrative describing any significant changes in industrial activities at the
permitted facility. Significant changes could include the addition or deletion of
work processes, changes in material handling practices, changes in material storage
practices, and/or changes in the raw materials used by the facility.
LWT 6. Certification of the development and implementation of a Stormwater Pollution
Prevention Plan for the permitted facility (Sign and return attached form).
If the final year analytical monitoring of the existing permit term has not been completed
prior to filing the renewal submittal,then the last years monitoring results should be submitted
within 30 days of receipt of the laboratory reports. (i.e. do not withhold renewal submittal
waiting on lab results)

Attachment 1
Site Maps

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Legend
Storm Water Outfall Location
Drainage Area
Impervious pe ous
Pervious Surfaces
j•� DUKE SW-o06a
Storm Water Outfall Location
mti ENERGY® NPDES Permit No.NCS000580
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®Feet NC OneMep NC CenRr tar Gwg,mh,,Inbrm—and M.".NC DOT-GIS Unl NCrbod,a MvpgPro9am oc sens�x—� NN noesrismno+aadac os9av
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_wa = Roxboro,Person County.North Carolina

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GDLDER ASSOCIATES NC.INC.
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GRAVING REFERENCES Nays GRAVING REVISIONS °f 1
1 2 3-}- 4 S 6 -{- 7 Mare wrr.ra 9P i �1G o.ou 'r 11 12

Attachment 2
Analytical Monitoring Results

Summary of Analytical Monitoring Data 2017-2020
Mayo Steam Electric Plant
NPDES Permit No. NCS000580
Stormwater
Outfall Sw 010
Date
Sampled 3/31/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 9/17/2020
Rainfall 0.94 0.95 0.75 1.75 1.21 1.89 2.03 0.8 0.54 0.49 2.61
pH 6.02 6.02 6.15 6.2 6.09 6.18 6.33 6.46 6.39 6.03 6.52
copper 0.0023 0.0056 0.0056 0.0035 0.00492 0.00511 0.0153 0.00514 0.0046 0.0037 0.00601
selenium 0.00039 0.00082 0.00028 <.00031 <.001 <.001 <.001 <.001 <.001 <.001 <.001
mercury 0.00000803 8.13 0.00000831 0.0000134 0.0000291 0.000021 0.0000416 0.00000464 550 0.0000142 0.00000999
zinc 0.0089 0.0081 0.0177 0.0082 0.019 0.016 0.028 0.005 0.008 0.009 <.005
tss 10.6 4.1 50.5 17.9 150 89 324 4 15 4.1 6.9
oil &grease <5.0 <1.1 <1.1 <1.1 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
Sulfate 6.4
COD 26
Ca 6600
Additonal Priority Pollutant Metals
Stormwater
Outfall Sw 010
Date
Sampled 3/31/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 9/17/2020
Ag <.00007 <.00007 <.00017 <.00007 <.0002 <.0002 <.0002 <.0002 <.0002 0.0002 <.0002
As 0.00044 0.00025 0.00054 0.00042 <.001 <.001 0.00129 <.001 <.001 <.001 <.001
Be 0.000035 0.000014 0.000083 0.000082 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cd <.0005 <.0005 0.000045 <.00005 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cr 0.0017 0.00084 0.0051 0.0028 0.00761 0.00534 0.0221 <.001 0.00236 0.00226 0.0017
Ni 0.0017 0.00076 0.0024 0.0019 0.0031 0.00259 0.0113 0.00164 0.00196 0.00154 0.00204
Pb 0.00053 0.00034 0.002 0.0013 0.00316 0.00207 0.00838 <.001 <.001 <.001 <.001
Sb <.0001 0.00011 0.00015 <.0001 <.0001 <.001 <.005 <.001 <.001 <.001 <.001
TI 1 <.000015 <.000015 1 <.000028 <.000015 1 <.0002 1 <.0002 1 <.0002 1 <.0002 1 <.0002 1 <.0002 1 <.0002
B 1 0.0222 1 0.0058 1 0.0117 1 <.05 1 <.05 1 <.05 1 <.05 1 <.05 1 <.05 1 <.05

Stormwater
Outfall SW 006A
Date
Sampled 5/22/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 7/23/2019 1/14/2020 9/17/2020
Rainfall 0.79 0.95 0.75 1.75 1.21 2.03 0.49 2.61
pH 6.21 6.02 6.15 6.43 6.15 6.47 6.41 6.39
copper 0.01 0.0056 0.0081 0.0041 0.00446 0.00459 0.00706 0.00272
selenium 0.056 0.00082 0.00026 <.00031 <.001 <.001 <.001 <.001
mercury 0.00000328 5.45 0.00000471 0.0000099 0.0000181 0.00000855 0.0000136 0.00000276
zinc 0.126 0.0049 0.0237 0.0134 0.02 0.007 0.011 0.007
tss 100 4.3 82.5 10 62 5 <2.5 <2.5
oil &grease 3.5 <1.1 <1.1 <1.1 <.5.0 <5.0 <5.0 <5.0
Sulfate
COD
Ca
Stormwater
Outfall SWO06A
Date
Sampled 5/22/2017 11/9/2017 2/4/2018 11/5/2018 3/21/2019 7/23/2019 1/14/2020 9/17/2020
Ag <.00007 <.0007 <.00017 <.00007 <.0002 <.0002 0.0002 <.0002
As 0.00027 0.00023 0.00038 0.00029 <.001 <.001 <.001 <.001
Be <.000010 0.000011 0.000085 0.000048 <.001 <.001 <.001 <.001
Cd <.00005 <.00005 0.000045 <.00005 <.001 <.001 <.001 <.001
Cr 0.00038 0.00045 0.0058 0.0016 0.00313 <.001 <.001 <.001
Ni 0.00063 0.00093 0.0029 0.0015 0.00194 0.00138 0.00211 <.001
Pb 0.00015 0.00021 0.0024 0.00078 0.00142 <.001 <.001 <.001
Sb 0.00014 <.0001 <.00012 <.0001 <.001 <.001 <.001 <.001
TI <.000015 <.000015 <.000028 <.000015 <.0002 1 <.0002 <.0002 <.0002
B <.05 1 <.05 <.05 1 <.05

Stormwater
Outfall SW 002
Date
Sampled 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 4/20/2020 9/17/2020 10/29/2020
Rainfall 1.89 2.03 0.8 0.54 0.49 0.52 2.61 0.84
pH 7.05 6.53 7.26 7.38 6.97 6.8 6.51 6.74
copper 0.0568 0.0144 0.0057 0.00342 0.00356 0.00357 0.00242 0.00305
selenium 0.00117 <.001 <.001 <.001 <.001 <.001 <.001 <.001
mercury 0.0000699 0.0000143 0.00000149 0.00000322 0.0000035 0.0000176 0.00000844 0.00000375
zinc 0.137 0.018 0.012 0.013 0.008 0.006 0.026 <.005
tss 1300 237 <2.7 9.13 15 24 4.5 <2.5
oil &grease <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0
Sulfate
COD
Ca
Stormwater
Outfall SW002
Date
Sampled 6/18/2019 7/23/2019 10/16/2019 11/12/2019 1/14/2020 4/20/2020 9/17/2020 10/29/2020
Ag <.0002 <.0002 <.0002 <.0002 0.0002 <0.0002 <.0002 <.0002
As <.005 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Be 0.00101 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cd 0.001 <.001 <.001 <.001 <.001 <.001 <.001 <.001
Cr 0.0602 0.0155 0.00261 0.00168 0,00245 0.00208 0.00105 <.001
Ni 0.0301 0.00718 0.00136 <.001 0.0027 0.00362 0.00174 0.00146
Pb 0.0191 0.0038 <.001 <.001 <.001 <.001 <.001 <.00146
Sb <.005 <.001 <.001 <.001 <.001 <.001 <.001 <.001
TI <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002 <.0002
B <.05 <.05 <.05 <.05 <.05 <.05 <.05 <.05

Attachment 3
Summary of Visual Monitoring Data

Summary of Visual Qualitative Monitoring Data 2017-2020
Mayo Steam Electric Plant
NPDES Permit No. NCS000580
Stormwater Outfall SW 010
Date Sampled 5/22/2017 11/9/2017 1/29/2018 4/24/2018 9/17/2018 11/5/2018 3/21/2019 6/18/2019 7/23/2019 10/16/2019
Color light tan light tan light tan light tan tan light tan tan tan tan light brown
Odor none none none none none none none none none none
Clarity 2 2 2 2 3 3 3 4 3 2
Suspended Solids 1 1 1 1 2 1 2 2 2 1
Floating Solids 1 1 1 1 3 1 3 3 3 1
Visable Foam none none none none none none none none none none
Visable Oil Sheen none none none none none none none none none none
Indication of
Erosion/Depostion none none none none none none none yes yes none
Rain Event
Accumulation 0.53 0.95 0.85 1.02 4.79 1.57 1.21 1.89 2.03 0.8
Outfall Status active active active active active active active active active active
Stormwater Outfall SW010
Date Sampled 11/12/2019 1/14/2020 4/20/2020
Color pale tan light tan light tan
Odor none none none
Clarity 2 2 2
Suspended Solids 1 1 1
Floating Solids 1 1 1
Visable Foam none none none
Visable Oil Sheen none none none
Indication of
Erosion/Depostion none none none
Rain Event
Accumulation 0.54 0.49 0.52
Outfall Status active active active

Stormwater Outfall SW 006A
Date Sampled 2/15/2017 5/22/2017 11/9/2017 1/29/2018 4/24/2018 9/17/2018 11/5/2018 3/21/2019 1/14/2020 4/20/2020
Color light tan light tan light tan light tan light tan tan light tan tan light tan clear
Odor none none none none none none none none none none
Clarity 1 1 2 1 2 3 3 2 2 1
Suspended Solids 1 1 1 1 1 2 1 2 1 1
Floating Solids 1 1 1 1 1 3 1 2 1 1
Visable Foam none none none none none none none none none none
Visable Oil Sheen none none none none none none none none none none
Indication of
Erosion/Depostion none none none none none none none none none none
Rain Event
Accumulation 0.19 0.53 0.95 0.85 1.02 4.79 1.57 1.21 0.49 0.52
Outfall Status active active active active active I active active active active active
Stormwater
Outfall SW 002
Date Sampled 10/16/2019 11/12/2019 1/14/2020 4/20/2020
Color clear pale tan pale tan light tan
Odor none none none none
Clarity 1 1 2 2
Suspended Solids 1 1 1 1
Floating Solids 1 1 1 1
Visable Foam none none none none
Visable Oil Sheen none none none none
Indication of
Erosion/Depostion none none none none
Rain Event
Accumulation 0.8 0.54 0.49 0.52
Outfall Status active active active active Notes: Outfall 002 added to permit effective March 21, 2019

Attachment 4
Summary of Best Management Practices

3.2.3.1 Nonstructural
Best Management Practices (BMP's) are methods,procedures,processes, prohibitions of
practices and other management controls which serve to eliminate,mitigate, or reduce
pollutant loadings in storm water discharges. Examples of BMP's for the Mayo Electric
Generating Plant include:
• Source Reduction
• Good Housekeeping
• Preventive Maintenance
• Visual Inspections
• Spill Prevention and Response
• Erosion and Sediment Control
• Storm Water Runoff Management
• Employee Training
• Recordkeeping and Reporting
• Recycling
• Treatment
3.2.3.2 Source Reduction
Source reduction measures reduced storm water pollution by reducing the quantity of
materials,which may contact storm water. The source reductions measures to be
implemented may require modifications in present work habits and practices. Example
components of source reduction are:
• Good Housekeeping
• Preventive Maintenance
• Visual Inspections
• Spill Prevention and Response
• Erosion and Sediment Control
Many of the components of source reduction are addressed as main components of the
BMP, therefore, source reduction should be considered under each of the other BMP
components.
ERM NC,INC. 3-4 398458

3.2.3.3 Good Housekeeping
Good housekeeping practices are designed to maintain a clean and orderly work
environment. Good housekeeping practices should be incorporated in the day-to-day
conduct of operations and maintenance. A clean and orderly work area reduces the
possibility of accidental spills caused by the mishandling of chemicals and equipment.
Well-maintained material and chemical storage areas reduce the possibility of storm
water mixing with pollutants. The following practices shall be performed on a regular
basis:
• Maintain clean and dry floors, ground surfaces,work,and process areas through
the use of brooms, shovels,vacuum cleaners,mops and cleaning equipment.
• Regular pickup and disposal of waste materials.
• Proper operation of equipment.
• Routine visual inspections by qualified personnel for leaks or spills, and for
conditions which may lead to a leak or spill (such as the hazardous waste
inspections being performed at various areas throughout the Mayo Plant).
• Training of employees in spill prevention and cleanup procedures.
• Bags storing dry chemicals shall be raised off the floor, preferably by pallet, to
prevent any unwanted interaction of the chemical with water.
• Walkways shall be maintained free of obstructions to facilitate inspection for
leaks or spills.
The Fossil Chemistry Technician assigned the ORC duties routinely inspects work and
storage areas for best housekeeping practices. Corrections are handled by work orders
tracked through Maximo, the Company work order management system, on an as
needed basis.
3.2.3.4 Preventive Maintenance
Mayo Plant has various inspections and site assessment practices in place to assist with
detection of potential problems. Preventive maintenance schedules vary based on the
potential risk by the source. In general, the Mayo Plant is well manned in order to
ensure the facility is a reliable and efficient source of electricity.
Preventive maintenance will be performed to ensure that storm water management
facilities and controls operate correctly and effectively and to reduce their breakdowns
and failure. Specific activities include:
• Periodic inspection, cleanout and maintenance of catch basins,containment
areas, ditches,and conveyance equipment.
• Periodic scheduled inspection and testing of equipment and systems,including
pumps,valves, pipes, storage tanks, and controls.
• Proper scheduled maintenance of equipment and facilities.
Additional preventive maintenance information will be provided as a separate section
of the SPPP. r�
ERM NC,INC. 3-5 398458

3.2.3.5 Visual Inspections
Visual inspections will be performed in conjunction with other BMP's, such as
housekeeping and preventive maintenance,and also as a separate activity (see section
3.5"Facility Inspection").
3.2.3.6 Spill Prevention and Response
Spill prevention will be achieved by good housekeeping,visual inspection, and
preventive maintenance, and through training of personnel in material handling and
storage procedures, and the use of equipment. Training in proper spill identification
and cleanup procedures, including the use of equipment and the notification and
documentation procedures,will be the main components of spill response. Specific
spill preventative measures will include:
• Piping protection, such as routing, coatings and wrappings, and cathodic protection
where appropriate.
• Adherence to current unloading procedures and practices, including monitoring
and verification of all connections and seals.
• Proper valve and control settings, and adequate labels,markings, and
communications, to ensure that accidental closures or openings do not occur.
• Adequate securities to prevent non-authorized access to facilities.
• Appropriate documentation of actions taken.
Spill response will be in accordance with existing Plant Procedures, including the Spill
Prevention, Control and Countermeasure (SPCC) Plan and the Hazardous Substance
Notification Procedure. Training is essential to a well-executed spill response.
Personnel will be trained to identify potential storm water pollution occurrences as may
occur during a spill event, and respond in the appropriate manner.
3.2.3.7 Erosion and Sediment Control
Areas under construction, or where accelerated erosion or sedimentation is occurring,
will be monitored and corrective measures will be implemented as necessary. A
Sediment Erosion Control Plan may be needed. The Environmental Site Coordinator
will decide. Vegetation or equivalent stabilization of the ground will be performed to
reduce/eliminate accelerated erosion.
3.2.3.8 Storm Water Runoff Management
Uncontaminated storm water will be diverted away from potential sources of
contamination, and discharged to a stabilized conveyance structure. Contaminated
waters will be directed to the appropriate treatment facilities prior to discharge.
Diversion efforts should be made to reduce the quantity of contaminated storm water
ERM NC,INC. 3-6 399458

that must be collected and treated depending on conditions. Vehicle washing should be
performed in areas away from storm water drains.
3.2.3.9 Employee Training
General training of employees will emphasize good housekeeping, and preventive
methods,procedures, and practices. Responsibilities will be clearly communicated to
personnel, including notification procedures for preventive and corrective measures.
Maintenance and inspection personnel will have the authority to follow-up on areas
requiring improvement. Plant personnel will trained to in safety and cleanup
operations, and recognize spill which may contribute to storm water pollution.
3.2.3.10 Recordkeeping and Reports
Training documentation will utilize the current training documentation tool.
Maintenance activities will be documented in the current Maximo work management
tool. Reports will be sent to the plant file 12520R located in the Environmental
Coordinator's Office.
3.2.3.11 Recycling
No recycling of contaminated storm water occurs at the Mayo Plant. Recycling of some
solid and universal wastes occurs at the Mayo Plant.
3.2.3.12 Treatment
Treatment measures will be the last step prior to the discharge of contaminated storm
water. Treatment is employed at the plant for those areas where, due to site constraints,
other BMP's have been found to be infeasible or too costly to implement. Periodic
vacuuming of storm drain catch basins will be conducted in high risk areas as needed.
ERM NC,INC. 3-7 39M58

Attachment 5
Narrative of Significant Site Changes
The most significant industrial changes at the site since permit
issuance on January 17, 2017 include the following:
Completion of all process water redirect work including
grading to remove all process flows from the ash basin to a
newly constructed lined retention basin. This project included
the rerouting and demolition of former SW outfalls 004 and
005 completed in May of 2019. These two outfalls were
included in the NPDES Industrial Stormwater permit issued
January 17, 2017 but were later placed in the August 1, 2018
NPDES Wastewater permit due to the constituents in the
discharge.

Attachment 6
Certification of Development and Implementation of
Stormwater Pollution Prevention Plan

STORMWATER POLLUTION PREVENTION PLAN
DEVELOPMENT AND IMPLEMENTATION
CERTIFICATION
North Carolina Division of Energy, Mineral, and Land Resources-Stormwater Permitting
Facility Name: Mayo Steam Electric Plant
Permit Number: NCS000580
Location Address: 10660 Boston Road
Roxboro,NC 27573
County: Person
"I certify, under penalty of law, that the Stormwater Pollution Prevention Plan (SPPP) document and all
attachments were developed and implemented under my direction or supervision in accordance with a system
designed to assure that qualified personnel properly gather and evaluate the information required by the SPPP.
Based on my inquiry of the person or persons who manage the system, or those persons directly responsible
for gathering the information, the information gathered is, to the best of my knowledge and belief, true,
accurate and complete."
And
"I certify that the SPPP has been developed, signed and retained at the named facility location, and the SPPP
has been fully implemented at this facility location in accordance with the terms and conditions of the
stormwater discharge permit."
And
"I am aware that there are significant penalties for falsifying information, including the possibility of fines and
imprisonment for knowing violations."
Sign (according to permit signatory requirements) and return this Certification. DO NOT
SEND STORMWATER POLLUTION PREVENTION PLAN WITH THIS CERTIFICATION.
Signature Date 0411712e
—t,nA `--OPol-e 6-M111t - QEIs S-r&-T,aaS
Print or type name of person signing above Title
SPPP Certification 10/13

Attachment 7
Fish Tissue Monitoring Results

Reference for Tissue Monitoring Species Composition Changes
Prior to 2019, the Mayo Reservoir Trace Element fish sampling program focused on plant operations in respect to
sustainable fish populations. With the implementation of flue gas desulfurization,zero liquid discharge system and
ash basin modifications,water column and fish tissue concentration for various metals have declined since 2014.
Prior to 2019, catfish species were included as part of the monitoring program to evaluate metals concentrations
across multiple trophic levels. Catfish were removed from the Mayo monitoring program in starting in 2019 due
to continued low metals(As, Hg,Se) concentrations in Mayo surface waters and fish tissues. Species collected
from 2019 on include Largemouth Bass (Micropterus solmoides), and sunfish (Lepomis spp.) based on
annual Fish Tissue Monitoring Plans approved by the Water Sciences Section of the North Carolina
Division of Water Resources.

Sample Date Location Fish Species Length Weight As Se Hg Dry-to fresh
(µg/g) W/O (µg/g) weight
ratio
4/26/2017 G 1 Largemouth Bass 295 342 0.2 4.3 1.04 0.21
4/26/2017 G 3 Largemouth Bass 320 500 0.2 5 1.05 0.21
4/26/2017 G 3 Largemouth Bass 331 498 0.2 4.7 1.02 0.20
4/26/2017 G 3 Largemouth Bass 294 340 0.3 4.2 0.73 0.22
4/26/2017 G 3 Largemouth Bass 323 460 0.2 4.4 0.89 0.21
4/26/2017 G 3 Largemouth Bass 320 438 0.2 5.1 0.89 0.20
4/27/2017 E 1 Bluegill 167 96 0.3 7.1 0.68 0.19
4/27/2017 E 1 Largemouth Bass 340 546 0.2 8.8 0.66 0.21
4/27/2017 E 1 Largemouth Bass 300 398 0.2 6.6 0.86 0.21
4/27/2017 E 1 Largemouth Bass 377 755 0.2 7.4 1.01 0.21
4/27/2017 E 1 Largemouth Bass 318 410 0.2 5.8 0.5 0.21
4/27/2017 E 1 Largemouth Bass 367 642 0.2 7 1.02 0.20
4/27/2017 E 1 Largemouth Bass 304 398 0.2 7.4 0.82 0.20
4/27/2017 E 3 Bluegill 166 81 0.2 6.1 0.47 0.20
4/27/2017 B 3 Largemouth Bass 320 420 0.2 7.9 0.67 0.21
4/27/2017 B 3 Largemouth Bass 383 684 0.4 10.3 1.23 0.21
4/27/2017 B 3 Largemouth Bass 405 842 0.2 8.5 1.14 0.21
4/27/2017 B 3 Largemouth Bass 369 684 0.2 10.4 0.91 0.21
4/27/2017 B 3 Largemouth Bass 400 954 0.2 10.2 1.09 0.21
4/27/2017 B 1 Largemouth Bass 411 848 0.2 14.4 1.25 0.19
5/25/2017 G 3 Bluegill 221 212 0.2 5 1.36 0.18
5/25/2017 B 1 Flat Bullhead 271 229 0.2 7.1 0.46 0.18
5/25/2017 B 1 Flat Bullhead 232 170 0.2 6.9 0.74 0.18
5/25/2017 B 1 Flat Bullhead 270 254 0.2 7.1 0.79 0.19
5/25/2017 B 1 Flat Bullhead 245 200 0.2 7.3 0.31 0.19
5/25/2017 B 1 Flat Bullhead 300 320 0.2 7.4 0.49 0.18
5/25/2017 B 1 Flat Bullhead 265 202 0.2 9.2 0.37 0.18
5/25/2017 G 1 Flat Bullhead 304 353 0.2 2 0.89 0.19
5/25/2017 G 1 Flat Bullhead 272 220 0.2 3.7 0.46 1 0.16
5/25/2017 G 1 Flat Bullhead 281 260 0.2 2.4 1.17 0.17
5/25/2017 G 1 White Catfish 411 856 0.2 2.3 1.07 0.19
5/25/2017 G 1 White Catfish 335 550 0.2 0.9 0.46 0.17
5/25/2017 G 1 White Catfish 415 946 0.2 2.2 0.39 0.18
5/25/2017 B 3 Largemouth Bass 403 934 0.2 11.6 1.86 0.20
5/25/2017 B 1 Bluegill 161 70 0.2 8 0.46 0.18
5/25/2017 B 1 Bluegill 142 47 0.2 7.9 0.66 0.19
5/26/2017 G 1 Bluegill 207 198 0.2 3 0.96 0.20
5/26/2017 E 1 Bluegill 170 93 0.2 5.3 0.48 0.19
5/26/2017 E 1 Brown Bullhead 340 592 0.2 1.6 0.27 0.18
5/26/2017 E 1 Brown Bullhead 315 457 0.2 1.1 0.37 1 0.19

Sample Date Location Fish Species Length Weight As Se Hg Dry-to fresh
(Pg/g) W/O (lig/g) weight
ratio
5/26/2017 E_3 Bluegill 166 92 0.2 5 0.86 0.17
5/26/2017 E 3 Bluegill 175 109 0.2 3.9 0.45 0.19
5/26/2017 -E-3 Bluegill 159 87 0.2 4.8 0.35 0.18
5/26/2017 E 3 Flat Bullhead 286 258 0.2 2.9 1 0.62 0.18
5/26/2017 E 3 Flat Bullhead 305 322 0.2 4.3 0.35 0.19
5/26/2017 E 3 Flat Bullhead 301 325 0.2 2.8 0.38 0.19
5/26/2017 E 3 Flat Bullhead 280 265 0.2 3.3 0.52 1 0.18
6/29/2017 G 1 Bluegill 198 143 0.2 3.6 1.07 0.19
6/29/2017 G_1 Bluegill 179 104 0.2 4.6 0.88 0.18
6/29/2017 G_1 Bluegill 199 133 0.2 4 0.54 0.17
6/29/2017 G 1 Bluegill 165 86 0.2 4.2 0.52 0.19
6/29/2017 B_3 Flat Bullhead 310 361 0.2 6.6 0.29 0.17
6/29/2017 B_3 White Catfish 365 660 0.2 3 0.39 0.16
6/29/2017 B_3 White Catfish 396 929 0.2 4 0.69 0.17
6/29/2017 B_3 White Catfish 439 1016 0.2 1.6 0.78 0.18
6/29/2017 B 3 Yellow Bullhead 289 312 0.2 5.1 0.75 0.18
8/22/2017 B_3 Bluegill 145 62 0.6 13.3 0.56 0.20
8/22/2017 B 3 Bluegill 192 130 0.2 5.5 0.44 0.17
8/22/2017 B_3 Bluegill 148 72 0.6 8.6 1 0.46 0.20
8/22/2017 B 3 Bluegill 158 76 0.9 9.1 0.41 0.23
8/22/2017 B_3 Bluegill 164 84 0.8 9.2 0.54 0.22
8/22/2017 B_3 Bluegill 153 60 0.5 8.2 0.52 0.21
8/22/2017 B 3 Brown Bullhead 181 76 0.2 3.1 0.27 1 0.19
8/22/2017 B 1 Bluegill 151 75 0.3 7.1 0.69 0.22
8/22/2017 B 1 Bluegill 148 56 0.4 6.7 0.82 0.19
8/22/2017 B 1 Bluegill 173 120 0.4 7.3 0.44 0.21
8/22/2017 B 1 Bluegill 168 91 0.2 8.4 0.27 0.20
8/22/2017 B 1 Largemouth Bass 290 352 0.2 5.9 0.45 0.22
8/22/2017 B 1 Largemouth Bass 228 157 0.2 6.9 0.43 0.21
8/22/2017 B 1 Largemouth Bass 322 476 0.2 8.1 0.92 0.21
8/22/2017 B 1 Largemouth Bass 1 225 142 0.2 6.7 0.72 1 0.21
8/22/2017 B 1 Largemouth Bass 177 78 0.2 4.7 0.71 0.20

Sample Date Location Fish Species Length Weight As Se Hg Dry-to fresh
(Pg/g) (µg/g) (Pg/g) weight
ratio
4/3/2018 B 1 Largemouth Bass 373 814 0.23 4.3 0.98 0.19
4/3/2018 B 1 Largemouth Bass 342 644 0.27 6.3 1.2 0.18
4/3/2018 B_1 Largemouth Bass 367 762 0.22 5.5 1.1 0.19
4/3/2018 B_1 Largemouth Bass 410 983 0.5 7.3 1 0.87 0.18
4/3/2018 B_1 Largemouth Bass 374 744 0.23 4.7 0.72 0.20
4/3/2018 B_1 Yellow Bullhead 266 264 0.5 4.8 0.19 0.18
4/3/2018 B 3 White Catfish 341 550 0.67 7.1 0.17 0.16
4/3/2018 B 3 White Catfish 316 458 0.59 6.6 0.21 0.17
4/3/2018 B 3 White Catfish 301 408 0.52 9.4 0.14 0.20
4/3/2018 B 3 White Catfish 316 460 0.74 6.7 0.39 0.19
4/3/2018 G 3 Flat Bullhead 282 295 0.5 1.9 0.44 0.19
4/3/2018 G 3 Flat Bullhead 281 275 0.5 2 0.33 0.16
4/3/2018 G_3 Flat Bullhead 285 302 0.49 2.2 0.28 0.19
4/3/2018 G 3 Flat Bullhead 260 217 0.5 1.4 0.61 0.19
4/3/2018 G 3 Flat Bullhead 276 282 0.5 1.8 0.31 0.17
4/3/2018 G 3 Flat Bullhead 280 278 0.49 1.8 0.38 0.17
4/3/2018 G 3 Largemouth Bass 363 765 0.16 3.4 1.1 0.20
4/3/2018 G 3 Largemouth Bass 347 694 0.21 3 0.89 0.19
4/3/2018 B 1 Largemouth Bass 343 600 0.3 5.7 0.61 0.21
4/4/2018 B 1 Flat Bullhead 313 400 0.5 3.8 0.32 0.18
4/4/2018 B 3 Largemouth Bass 385 827 0.24 5.5 0.96 0.20
4/4/2018 B 3 Largemouth Bass 388 905 0.32 8 2.2 0.17
4/4/2018 B 3 White Catfish 333 510 0.43 7.5 0.27 0.19
4/4/2018 B 3 White Catfish 283 380 0.69 6.8 0.16 0.18
4/4/2018 G 1 Largemouth Bass 333 540 0.5 3.4 1.2 0.20
4/4/2018 G 1 Largemouth Bass 375 832 0.16 3.5 1.2 0.20
4/4/2018 G 1 Largemouth Bass 301 394 0.49 3.1 0.95 0.20
4/4/2018 G 1 Largemouth Bass 341 604 0.5 3.4 1.4 0.20
4/4/2018 G 3 Bluegill 164 87 0.5 2.1 0.34 0.18
4/4/2018 G 3 Bluegill 170 80 0.37 3.6 0.19 0.18
4/5/2018 B 3 Largemouth Bass 370 745 0.22 6.7 0.56 0.20
4/5,/2018 B 3 Largemouth Bass 388 940 0.26 4.3 0.59 0.22
5/22/2018 B 3 Bluegill 214 214 0.25 5 0.42 0.16
5/22/2018 B 3 Largemouth Bass 405 770 0.3 6.8 1.8 0.19
5/22/2018 B 3 Largemouth Bass 400 948 0.27 6.9 0.96 0.19
10/29/2018 B 1 Bluegill 186 119 0.45 5.9 0.19 0.18
10/30/2018 G 3 Bluegill 183 109 0.36 2.8 0.29 0.19
10/30/2018 G 3 Bluegill 186 112 0.26 2.8 0.47 0.18
10/30/2018 G 3 Bluegill 167 77 0.5 2.5 0.35 0.19

Sample Date Location Fish Species Length Weight As Se Hg Dry-to fresh
(µg/g) (ig/g) (Pg/g) eigh
rati
10/30/2018 G 3 Bluegill 181 95 0.5 2.3 0.23 0.19
10/30/2018 B_1 Bluegill 205 154 0.51 6 0.32 0.19
10/30/2018 B 3 Bluegill 182 100 0.48 4.2 0.18 0.19
10/30/2018 B 3 Bluegill 177 95 0.58 6.2 1 0.15 0.20
10/30/2018 B 3 Bluegill 177 95 0.35 5.4 0.4 0.18
10/30/2018 B_3 Bluegill 179 99 0.54 4.8 0.22 0.19
10/30/2018 B 3 Bluegill 164 75 0.55 6.2 0.19 0.20
11/19/2018 B 1 Bluegill 214 180 0.4 5.4 0.51 0.18
11/19/2018 B_1 Bluegill 188 103 0.56 6.6 0.28 0.18
11/19/2018 B_1 Bluegill 201 138 0.5 4.2 0.18 0.20
11/19/2018 B 1 Bluegill 179 91 0.63 6.2 0.18 0.19
11/19/2018 B 1 Flat Bullhead 242 155 0.33 4.2 0.14 0.18
11/19/2018 B 1 Flat Bullhead 283 288 0.23 4.3 0.32 0.19
11/19/2018 B 1 Flat Bullhead 253 212 0.16 1 3.3 0.28 0.17
11/19/2018 B 1 Flat Bullhead 249 188 0.32 1 3 0.3 0.17

Sample Date Location Fish Species Length Weight As Se Hg Dry-to fresh
(µg/g) (µg/g) (µg/g) weight
ratio
4/3/2019 B_3 Redear Sunfish 227 181 0.83 9.22 0.3 0.21
4/3/2019 B 3 Redear Sunfish 212 139 0.9 7.45 0.3 0.20
4/3/2019 B_3 Redear Sunfish 220 150 0.85 5.93 0.3 0.20
4/3/2019 B 3 Redear Sunfish 240 215 0.8 5.47 0.31 0.21
4/3/2019 B 3 Redear Sunfish 236 200 0.93 6.63 0.37 0.19
4/3/2019 B 3 Redear Sunfish 246 225 0.79 7.64 0.3 0.19
4/3/2019 B 1 Largemouth Bass 377 774 0.92 7.05 0.71 0.20
4/3/2019 B 1 Largemouth Bass 361 728 0.87 5.91 0.86 0.21
4/3/2019 B 1 Redear Sunfish 237 190 0.95 9.21 0.5 0.20
4/3/2019 B 1 Redear Sunfish 233 175 1.12 7.55 0.41 0.19
4/3/2019 B 1 Redear Sunfish 249 218 0.82 12.23 0.3 0.19
4/3/2019 B 1 Redear Sunfish 231 171 1.07 7.19 0.59 0.17
4/4/2019 G_1 Largemouth Bass 346 684 0.84 4.15 1.02 0.20
4/4/2019 G 1 Redear Sunfish 195 105 0.86 3.99 1.27 0.18
4/4/2019 G 1 Redear Sunfish 205 123 0.81 4.37 1.34 0.18
4/4/2019 G i Redear Sunfish 226 151 0.87 4.78 0.91 0.17
4/4/2019 G 3 Largemouth Bass 320 424 0.9 3.54 0.7 0.21
4/4/2019 G_3 Largemouth Bass 336 556 0.86 3.41 0.68 0.22
4/4/2019 G 3 Largemouth Bass 354 665 1.11 3.46 0.91 0.21
4/4/2019 G 3 Largemouth Bass 379 814 0.93 3.47 0.93 0.20
4/4/2019 G 3 Largemouth Bass 341 629 0.96 3.4 0.73 0.21
4/4/2019 G 3 Redear Sunfish 210 146 0.89 4.73 0.32 0.19
4/4/2019 G 3 Redear Sunfish 225 181 1.02 4.2 0.4 0.19
4/4/2019 G_3 Redear Sunfish 208 137 0.85 4.6 0.3 0.20
5/8/2019 B_1 Redear Sunfish 245 233 0.95 11.66 0.8 0.20
5/8/2019 B_1 Redear Sunfish 195 111 0.98 8.77 0.36 0.20
5/9/2019 B_3 Largemouth Bass 405 758 1.06 9.17 1.79 0.21
5/9/2019 B_3 Largemouth Bass 381 739 1.01 6.68 0.79 0.17
5/9/2019 B 3 Largemouth Bass 370 702 0.89 7.24 0.66 0.19
5/9/2019 B 3 Largemouth Bass 305 391 0.99 6.37 0.55 0.21
5/9/2019 B 3 Largemouth Bass 354 518 0.85 6.84 0.65 0.21
5/9/2019 B 3 Largemouth Bass 355 636 0.97 4.8 0.63 0.20
5/9/2019 BT1 Largemouth Bass 368 613 0.91 5.14 0.71 0.21
5/9/2019 B 1 Largemouth Bass 290 333 1.02 4.94 0.42 0.21
5/9/2019 B 1 Largemouth Bass 415 1120 0.88 6.36 0.94 0.20
5/9/2019 B 1 I Largemouth Bass 1 390 849 0.91 7.87 0.88 0.21

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NORTH CAROLINA -

Attachment 8
NPDES General Permit Renewal Guidance Letter
with updated NCG120101 results

DUKE 2500 Duke Energy
Fairfax Road
ENERGY, Greensboro,NC 27407
File: Mayo12520-R September 6,2018
Ms. Bethany Georgoulias
North Carolina Division of Environmental Qual ity
1628 Mail Service Center
Raleigh,NC 27699-1628
Subject: Duke Energy Progress, LLC.
Mayo Electric Generating Plant
NPDES General Permit Renewal Guidance
NCG 120101
Dear Ms.Georgoulias:
As recently discussed, Duke Energy requests guidance and clarification on the renewal of the
NCG120101 general stormwater permit for the Mayo Steam Plant Monofill.The initial certificate of
coverage was issued to Duke Energy on January 6,2014.Coverage under this general permit was issued
with amended conditions requiring additional sampling. Please advise if the renewal of the general permit
will continue to require this augmented sampling schedule.
The NCG120101 has been problematic with the requirement to monitor fecal coliform due to the
abundant wildlife around the monofill. Duke Energy sought and received tier relief from monthly
monitoring of fecal coliform from DEQ in December of 2017. Unlike the sanitary landfills the
NCG12000 permit was developed for,the Mayo Monofill receives only coal combustion residuals with
wildlife being the only possible source of fecal contamination.
Duke Energy plans to request a modification of NPDES Industrial Stormwater Permit NCS060580 in the
near future to include the three stormwater outfalls at the Mayo Monofill currently covered by permit
NCG120101.The industrial activity at the monofill,transport of materials, is similar in nature to the
activity at the Station's stormwater outfall 010.
As you requested, included with this correspondence is all stormwater sampling data gathered under
permit NCG 120101 to date from the Mayo Monofill for your review.Should you have any questions
please contact me at [e-mail] or at 1-336-8544916.
Sincerely,
Lori To]lie

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