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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 Beaufort Gazette The Herald-Pock HIM �l Nue�,o Herald-Miami Sun NeWs-Myrtle Reach Belleville .. Harald Sur,-Dumam Modesto Bee The N�Tribure Tacoma Beffirigharn Herald Idaho Statesman Raleigh Nevv5&Ob5er,�r Tlh�Telegraph-Macon and Packet The Olympian San Lum Ohispo Tribune- :. Charlotte Obser,ver Leriangton I-Ituald-Leader Fot Worth Slar-T�rlag�rrt Wichita Eagle Fresno Bee, Mrami HemJd Sun Head-Biloxi 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 joyce.sanford@deq.nc.gov 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<Brianna.Young@deq.nc.gov> Sent: Wednesday,June 14, 2023 8:35 AM To: Guyer, Shawn <shawn.guyer@deq.nc.gov> 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) Brianna.Young@deq.nc.gov(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 <Lori.Tollie@duke-energy.com> 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: (336) 408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@deq.nc.gov> Sent: Friday,July 7, 2023 10:13 AM To:Tollie, Lori White<Lori.Tollie@duke-energy.com> Cc:Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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) Brianna.Young@deq.nc.gov(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<Lori.Tollie@duke-energy.com> Sent:Thursday,June 29, 2023 9:51 AM To:Young, Brianna A<Brianna.Young@deq.nc.gov> Cc:Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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: (336) 408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@deq.nc.gov> Sent:Wednesday,June 14, 2023 8:36 AM To: Bednarcik,Jessica L<Jessica.Bednarcik@duke-energy.com> Cc:Tollie, Lori White<Lori.Tollie@duke-enerRy.com>;Winston, Cynthia C<Cynthia.Winston@duke-energy.com>; Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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) Brianna.Young@deg.nc.gov(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) Brianna.Young@deq.nc.gov(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<Lori.Tollie@duke-energy.com> Sent:Thursday,June 29, 2023 9:51 AM To:Young, Brianna A<Brianna.Young@deq.nc.gov> Cc:Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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: (336)408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@deg.nc.gov> Sent:Wednesday,June 14, 2023 8:36 AM To: Bednarcik,Jessica L<Jessica.Bed narcik@duke-energy.com> Cc:Tollie, Lori White<Lori.Tollie@duke-energy.com>;Winston, Cynthia C<Cynthia.Winston@duke-energy.com>; Wilson, Leanne<Leanne.Wilson@duke-energy.com>;Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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) Brianna.Young@deg.nc.gov(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: 336-597-7307 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: (919) 707-3648 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<Brianna.Young@ncdenr.gov> Sent:Thursday, May 4, 2023 11:03 AM To:Valentine,Thad <thad.valentine@ncdenr.gov> Cc: Cook, Brittany<Brittany.Cook@ncdenr.gov> 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) Brianna.Young@ncdenr.gov(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 <thad.valentine@ncdenr.gov> Sent: Wednesday, May 3, 2023 2:21 PM To:Young, Brianna A<Brianna.Young@ncdenr.gov> Cc: Cook, Brittany<Brittany.Cook@ncdenr.gov> 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<Brianna.Young@ncdenr.gov> Sent:Thursday, May 4, 2023 11:01 AM To:Valentine,Thad <thad.valentine@ncdenr.gov> Cc: Lawyer, Mike <mike.lawyer@ncdenr.gov>; Cook, Brittany<Brittany.Cook@ncdenr.gov> 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) Brlanna.Young@ncdenr.gov(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 <thad.valentine@ncdenr.gov> Sent:Thursday, May 4, 2023 10:49 AM To:Young, Brianna A<Brianna.Young@ncdenr.gov> Cc: Lawyer, Mike <mike.lawyer@ncdenr.gov>; Cook, Brittany<Brittany.Cook@ncdenr.gov> 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 <Lori.Tollie@duke-energy.com> 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: (336) 408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@ncdenr.gov> Sent: Friday,August 5, 2022 8:51 AM To: Bednarcik,Jessica L<Jessica.Bed narcik@duke-energy.com> Cc:Tollie, Lori White<Lori.Tollie@duke-energy.com> 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) Brianna.Young@ncdenr.gov(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 <Lori.Tollie@duke-energy.com> 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: (336) 408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@ncdenr.gov> Sent:Wednesday,August 10, 2022 3:12 PM To:Tollie, Lori White<Lori.Tollie@duke-energy.com>; Bednarcik,Jessica L<Jessica.Bed narcik@duke-energy.com> Cc:Winston, Cynthia C<Cynthia.Winston@duke-energy.com>; Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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) Brianna.Young@ncdenr.gov(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<Lori.Tollie@duke-energy.com> Sent: Wednesday,August 10, 2022 1:48 PM To:Young, Brianna A<Brianna.Young@ncdenr.gov>; Bednarcik,Jessica L<Jessica.Bednarcik@duke-energy.com> Cc:Winston, Cynthia C<Cynthia.Winston@duke-energy.com>; Wilson, Leanne<Leanne.Wilson@duke-energy.com>; Slade,Joseph Heath <Joseph.Slade@duke-energy.com> 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: (336) 408-2591 Office: (336) 854-4916 From:Young, Brianna A<Brianna.Young@ncdenr.gov> Sent: Friday,August 5, 2022 8:51 AM To: Bednarcik,Jessica L<Jessica.Bednarcik@duke-energy.com> Cc:Tollie, Lori White<Lori.Tollie@duke-energy.com> 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) Brianna.Young@ncdenr.gov(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. Draovitch@duke-energy.com 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: Tom.Copolo@duke-energy.com Permit Information Permit Contact: Lori Tollie Mailing Address: 2500 Fairfax Road Greensboro, NC 27407 Phone Number: 336-854-4916 Fax Number: E-mail address: Lori.Tollie@duke-energy.com 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 X p'!- ty Location f (Ma not to scale) � � 5 K;tuccW �• _ IRGINIA Latitud6e:36i31'361N _. -_ y N _ ARUi R?FI' C `.CIA 1 LonglWde:79°�63 7"W 0 _ a J EE ''ff t, r �� >r Pervious=5>73 Acres `? 'ten Impervious=2.01 Acres EM 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 0 75 150 N�co McePN a e®doaGa�uo mn lgammo pep mw ERM Duke Energy Progress 9 4 1ym.NC 911 Board Mayro Steam Electnc Plant ®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 10660 Boston Road _wa = Roxboro,Person County.North Carolina a � Facility Location (Map not to scale) 3p T c 50 Np4 "�R s a M1 a fi ,r a i a C.lustM 532 r .'."' 32 2 v GiNIA h ,t CAROL 528 w cn a 534 ✓' a�" SSB 512 Ci" Pervious=28.91 Acres 516 524 52e ) ' m518 w 4 59 --v S s Sos Impervious=0.61 Acres a-r 600 a -- ._. 552 1522 b Ory b on b� S�-()10 Aga ,' "<+y O - -' Longitude 3d�31 17"N ` ngitude. 79'53 39'NJ sop 596 _ 43b 92486 .` h e 'a S ,x S r 568 Legend -ego S9a 598 k Storm Water Outfall Location ` rain Area }r,• D age 526 Reza a' L Impervious Surfaces d:3o 'w 49 Pervious Surfaces S ! (.� DUKE ago oa Storm Waterer Outfutfall Location Or"k �'rC ENERGYe ERM NPDES PermitEnergy 0.gCS000580 ON o A � tj B v'wr-9m,ezal9N m tG 9�nnK soc y �mm Duke Ener Progress 0 150 300 'Nco MgNCC erlaGco9revn t11—t* eNelyss,NG911Board Ma roSteamElectricPlant ®Feet dko"- _ NCG Mp NCC R r Gao9r�hic to ameron me McNss.NC DOT.Mull. s—.ry y { -: Ncvwoevls�sMsvv�sevroarem. sx•». aFW�ywP w.. miwmn 10660 ersonC Countyton.North - o-wm s�n,kee��waa^=s.swxmeo.eoows�srva_swmsmm Roxboro.Person Count.North Carolina 9 t0 11 12 y i t t DRAINAGE /� � � � � 1 AREA#3CUTFALL `71ii f J SKIMMER BASIN{ B /\✓/ `V % _ DRAINAGE � I R � AREA#1 I, Mill i D ���I �, __-_ I;I B %y• � II'�' PERMANENT E 1 SEDIMENT L i I,t BASIN#1 ` 1s, ouTfAufn 1 p � AREA#�2 DRAINAGE PERMANENT SED ENT ._ o GExEaNL srDRNVAFER PERNIr-att svrrtNl c7F crF ca a7-13 �nKrolAocw �* PROGRESS ENERGY CAROL INAS, INC. y //1'R^�VI POWER OPERATIONS GROUP o pw�a'EJy IT WYO nK. Assodates MONOFILL GENSIITE ST DIAGRAM pTER PERMIT GDLDER ASSOCIATES NC.INC. GREE 190R0, C srz_AIM10 1'NNF IN WYO OOP MONOflLL 1 ° 7 u 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 Mayo Creak Mayo Laka Rd. N A outlay 63 002 + �► B 0 0.5 1 2 Miles > , l,telt. 0 0.75 1.5 3 Kilometers ftuft" �a Sampling Locations: Electroflshing Transacts J Public Boat Ramp aG 00 G 01 G C�cp Rd Mayo Swam Electric Plant 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 Lori.Tollie@duke-energy.com or at 1-336-8544916. Sincerely, Lori To]lie E ry N a x w \ o 0 0 0 o N E o 0 0 0 0 V -v 6v � E �g E a mo g m � ry F JE o. o 0 'o 0 0 0 0 o d E o 6 ov v ov v f E o c c x E o 0 0 0 0 0 0 0 0 0 v m o m co a o a H N O O p p O O G O 0 0 0 O 0 0 0 O 0 0 0 0 0 0 0 0 .i 6 6 v T v v E o O O 0 0 0 U O O O n N ti x q m m 9 m m � � �6 a6 6 J ti m n «Q n n � oo �c �6 �u o n ad �c n o o n . m ^ g c 4 e n n N m o c $ ^ I m m ry m n n oI o ap o o •' m m o 0 0 E o 0 0 0 o o `° O o $ ry o o o .� o o o o 0 0 0 0 0 0 0 0 0 0 0 0 0 o v o 0 0 0 0 0 0 0 o J v o E o 0 0 0 0 ov 'J o o " o 0 0 0 0 0 �o' m m o 0 0 `" " " o o ^o 0 0 0 0 0 0 $ o I'll$ o `, o0aE 0 0 0 0 0 0 0 0 0 0 0 6 0 0 o o 0 0 0 0 0 00g �' 6o006 0 0 o 6 0 o 0 o v v 6 6 6 6 6 6 6 6 o 0 o v o ry o o O o 0 0 0 0 11.9 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 o o C m J o p O o 0 0 a E o 0 0 00 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 00 00 0 0 o E o 00 0 0 0 1 o v .. v ,-. e ro m m E o o o 0 µ o 0 0 0 0 C m o 0 0 '^ o o m y .+ ry o m o o ry m ry ry .5 o 0 0 0 0 0 O E ri ni o `-; m a .-� ry ry E o 0 0 0 0 0 v m w m m o •• •• •-� °c °c c m m m m m 6 m ry m m m o 0 0 oo N ^ �v n w t`E c o o 0 o I v � o o - '� "avv `i - c ° m o ry ry rv \o 0 o ry ry ry C ry ry ry � m m m ry n`..° d o.m\. m �+ �' ry ry ry .rvi o m m m„^ �c m m m.`-; - .ry uaw .- - v a a- —- m—m 0 E TF ° o o z21 cl -1-1 d E m 9 Z C A C A � � 7 O u .