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Home My WebLink AboutNC0000396_Report_20200630 etas DUKE James Wells ENERGY, Vice President Environmental, Health and Safety Programs&Environmental Sciences 526 South Church Street Charlotte, NC 28202 (980)373-9646 June 30, 2020 Via Overnight Mail S. Daniel Smith RECEIVED Director of Water Resources North Carolina Department of Environmental Quality JUL 0 9 2020 1617 Mail Service Center r Raleigh,NC 27699-1617 NQIDWRINPDES Bob Sledge North Carolina Department of Environmental Quality Water Quality Permitting Program Division of Water Resources 1617 Mail Service Center Raleigh,NC 27699-1617 Subject: Report Under Special Order by Consent—EMC SOC WQ S 17-010 Duke Energy Progress, LLC—Asheville Steam Electric Plant NPDES Permit NC0000396 Seep Characterization Report Dear Messrs. Smith and Sledge: On behalf of Duke Energy Progress, LLC (DEP), I am submitting to you the Asheville Steam Electric Plant Seep Characterization Report summarizing the findings of the post decant sampling event and recommendations relative to seep dispositions and the upcoming CAP Amendment as required by the Asheville Steam Electric Plant NPDES Permit NC0000396 Special Order by Consent(SOC), SOC No. S 17-010 Sections 2.b.2) and 2.b.3). As required by the SOC, I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Messrs. Smith and Sledge June 30, 2020 Page 2 Please direct any questions concerning the Asheville Steam Electric Plant NPDES Permit NC0000396 SOC No. S17-010 to Robert Wylie at(704) 382-4669 and to Chris Hallman at(980) 373-7892 relative to the Seep Characterization Report. Sincerely, C 6&— - L James Wells Vice President, Environment, Health& Safety- Programs and Environmental Sciences Duke Energy Attachment: Asheville Steam Electric Plant Seep Characterization Report cc: Richard Baker, Duke Energy Shannon Langley, Duke Energy Robert Wylie, Duke Energy Chris Hallman, Duke Energy Teresa Williams, Duke Energy Paul Draovitch, Duke Energy Matt Hanchey, Duke Energy RECEIVED synTerra JUL. 0 9 2020 NCDEQIDWRINPDES SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT EMC SOC WQ S17-010 26 DUKE ENERGY LANE ARDEN, NC 28704 JUNE 2020 PREPARED FOR jT DUKE ENERGY. PROGRESS DUKE ENERGY PROGRESS, LLC Grant Barrier P ject pager To lati , L #2410 Site Technical Lead Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra EXECUTIVE SUMMARY SynTerra has prepared a Seep Characterization Report pertaining to the Asheville Steam Electric Plant (Asheville or Site) to evaluate whether historical storage of coal ash has affected surface waters downgradient of the 1964 Ash Basin and the former 1982 Ash Basin. This report was prepared on behalf of Duke Energy Progress, LLC (Duke Energy). ES.1 Introduction A Special Order by Consent (SOC) SOC WQ S17-010, approved on October 10, 2018, addresses management of seeps from Duke Energy's coal ash basins during the process of basin closure under the Coal Ash Management Act of 2014 (CAMA), G.S. 130A- 309.200 through 130A-309.231 and the federal Coal Combustion Residuals (CCR) rule, 40 CFR Parts 257 and 261. In addition to monitoring requirements, the SOC contains requirements for identifying new seeps and documenting the physical characteristics of previously identified seeps. Compliance requirements specified in the SOC include: • Within 90 days after the Asheville coal-fired electricity generation ceases, and no later than April 30, 2020, remaining seeps, if not dispositioned in accordance with the SOC, will be characterized and Duke Energy will be required to submit an Interim Seep Report identifying new seeps and documenting the physical characteristics of previously documented seeps. (This was report was submitted to DEQ on April 24, 2020.) • Additional characterization of seeps not dispositioned in the Interim Seep Report will be necessary, and a summary of findings provided within a Seep Characterization Report must be submitted no later than June 30, 2020. • If deemed necessary, an amendment to the Corrective Action Plan or Closure Plan describing future seep management must be submitted no later than August 31, 2020. A physical inspection was completed in March 2020 to identify new seeps and document the physical characteristics of previously documented seeps. No new seeps were identified during this inspection. The findings of the March 2020 inspection are documented in the Interim Seep Report (SynTerra, April 2020). Observations during the March 2020 physical inspection were evaluated to determine whether any remaining seeps identified during the inspection are candidates for dispositioning in accordance with the SOC. Page ES-1 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Samples were collected in April 2020 from remaining seeps identified downgradient of the ash basins to facilitate additional characterization of those seeps. The sampling data were evaluated to determine whether any constituents are present in the remaining seeps that have the potential to be considered for corrective action based on comparison to applicable North Carolina Administrative Code, Title 15A, Subchapter 02B Surface Water and Wetland Standards (02B). In addition, a review and determination of the jurisdictional status of remaining seeps is included in this report for further characterization. ES.2 Key Findings Key findings regarding the seep characterization presented in this report include: • The March 2020 physical inspection identified three seeps (C-03, C-05, and 64E0- 03) that are candidates for dispositioning based on dry or non-flowing conditions observed at these locations for at least three consecutive quarters. • Constructed seeps 64E0-01 and 02 are now covered via the station's National Pollution Discharge Elimination System (NPDES) permit. • A preliminary comparison of April 2020 analytical results to 02B surface water standards identified only two (2) out of 20 sampled locations that had constituent concentrations greater than background or calculated hardness dependent 02B surface water standards (N-01 and Ponded Water F). • N-01 should be considered for dispositioning based on analytical results that do not indicate the presence of CCRs. Concurrence with the North Carolina Department of Environmental Quality (NCDEQ) Division of Water Resources (DWR) would be required to confirm this consideration. • Ponded Water F is non-jurisdictional and has not been observed to flow to waters of the State (WOS) or Waters of the United States (WOTUS) during annual inspections and three previous quarterly SOC sampling events and should be considered for dispositioning. • With concurrence from the DWR on the status of seeps proposed to be dispositioned, data from remaining seeps indicate that corrective action will not be necessary. Page ES-2 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress, LLC SynTerra TABLE OF CONTENTS SECTION PAGE EXECUTIVE SUMMARY ES-1 1.0 INTRODUCTION 1-1 1.1 Decanting (Dewatering) Summary 1-2 1.2 Seep Characterization Evaluation 1-2 2.0 FINDINGS 2-1 2.1 Physical Inspection 2-1 2.2 Seep Sampling 2-2 2.3 Jurisdictional Status of Seeps 2-4 2.4 Dispositional Status of Seeps 2-5 2.4.1 Dispositioned 2-5 2.4.2 Non-Dispositioned 2-5 2.4.3 Changes of Status 2-6 2.5 Decanting/Dewatering/Ash Basin(s) Status 2-6 2.6 Ash Basin Closure Status/Corrective Action Plan 2-7 3.0 SEEPS TO BE ADDRESSED 3-1 4.0 CONCLUSION 4-1 5.0 REFERENCES 5-1 LIST OF FIGURES Figure 1 Seep Locations and Inspection Areas LIST OF TABLES Table 1 Seep Locations and Descriptions Table 2 Seep Sampling Results Table 3 Comparison of 02B Hardness Dependant Standards LIST OF APPENDICES Appendix A Photographs Appendix B N-01 Historical Analytical Results Appendix C Groundwater Elevation and Topography Figures Page i Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra LIST OF ACRONYMS 02B North Carolina Administrative Code, Title 15A, Subchapter 02B, Surface Water and Wetland Standards BTV Background Threshold Values CCRs coal combustion residuals CSA comprehensive site assessment CAP corrective action plan DWR Division of Water Resources EMC Environmental Management Commission IAL Interim Action Limit JD jurisdictional determination mg/L milligrams per liter NCAC North Carolina Administrative Code NCDEQ North Carolina Department of Environmental Quality NC L.G. North Carolina Licensed Geologist NPDES National Pollutant Discharge Elimination System Site Asheville Steam Electric Plant SOC Special Order by Consent SOP standard operating procedure USACE United States Army Corp of Engineers WOS Waters of the State WOTUS Waters of the United States Page ii Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 1.0 INTRODUCTION Coal-fired generation of electricity ceased at the Asheville Steam Electric Plant (Asheville or Site) in January 2020. On March 30, 2020, Todd Plating (NC L.G. #2410) of SynTerra inspected the Site property for existing and potential new seeps. After the seep inspection, SynTerra prepared an Interim Seep Report (SynTerra, April 2020) documenting the findings of the seep inspection as required by the North Carolina Environmental Management Commission (EMC) Special Order by Consent(SOC) WQ S17-010. This requirement can be found in the Compliance Schedule (Section 2.b.1) of that SOC. After submittal of the Interim Seep Report, the next step in the SOC Compliance Schedule (Section 2.b.2) is to conduct a characterization of those seeps identified during the seep inspection. That section of the SOC describes requirements for seep characterization as follows: "If any seeps (including both constructed and non-constructed seeps) have not been certified by the Director of DWR as dispositioned . . . , Duke Energy shall conduct a characterization of those seeps. Duke Energy shall submit a report on the findings of these characterizations ("Seep Characterization Report") to the Director of DWR no later than June 30, 2020. The Seep Characterization Report must include all sampling data for each remaining seep as well as Duke Energy's evaluation of the jurisdictional status of all seeps at the Asheville Facility. The determination regarding whether a surface water feature is a classified water of the State rests with DWR." In April 2020, SynTerra collected samples for analysis from each seep location identified in the Interim Seep Report (Table 1). Samples were collected in accordance with Duke Energy's Standard Operating Procedure (SOP) for Seep Sampling (Duke Energy, 2016). Several locations were not sampled due to dry or stagnant conditions, insufficient flow, or other observed conditions that would preclude the ability to collect a valid, representative sample as outlined in Duke Energy's 2016 SOP for seep sampling. This sampling was conducted to facilitate characterization of those seeps as required by the SOC. The April 2020 seep sampling results are provided in Table 2. This Seep Characterization Report documents the results of those findings and provides an evaluation of the jurisdictional status of all remaining seeps at the Site. Page 1-1 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 1.1 Decanting (Dewatering) Summary Dewatering of the 1982 Ash Basin began in 2007 and was completed in 2016 when the basin was decommissioned. Seep K-02 was dispositioned because of non-flowing conditions as a result of dewatering the 1982 Ash basin, as noted in the SOC. Dewatering of the 1964 Ash Basin began in 2017 and is ongoing. 1.2 Seep Characterization Evaluation The purpose of seep characterization is to evaluate whether historical storage of coal ash has affected surface waters downgradient of the ash basins. This includes evaluation of the physical characteristics, chemical composition, and jurisdictional determination of the seeps. The following methods were used in this evaluation: Physical Characteristics SynTerra conducted a comprehensive survey on March 30, 2020 of areas downgradient of the ash basins to identify new seeps, and to document the physical characteristics of previously documented seeps. This survey included identification of the seeps by approximate latitude and longitude and date-stamped photographs of their appearance (Appendix A). The seeps were evaluated based on appearance, current flow conditions, and comparison with historical physical conditions. A summary of the findings of the survey are included in the April 2020 Interim Seep Report. Chemical Composition In April 2020, SynTerra collected samples from each seep location to analyze for parameters required to be analyzed and reported in Attachment B of the SOC. Samples were not collected from locations where there were dry or stagnant conditions, insufficient flow, or other observed conditions that would preclude the ability to collect a valid, representative sample as outlined in Duke Energy's March 2016 SOP for seep sampling. These data were evaluated to determine whether any reported parameters are present in the remaining seeps that have the potential to be considered for corrective action based on preliminary comparison to applicable North Carolina Administrative Code, Title 15A, Subchapter 02B, Surface Water and Wetland Standards (02B). Page 1-2 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Jurisdictional Determination A jurisdictional determination (JD) (SAW-2014-0189) pertaining to the Site, identifying Waters of the United States (WOTUS), was approved by the U.S. Army Corps of Engineers (USACE) on May 19, 2016. SynTerra compared data from the remaining seep locations with the USACE-approved jurisdictional streams and wetlands data provided by the JD to satisfy requirements within the SOC. The final determination of jurisdictional status of a surface water feature as a classified WOS or WOTUS rests with the DWR. Page 1-3 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 2.0 FINDINGS 2.1 Physical Inspection On March 30, 2020, Todd Plating of SynTerra inspected the Site property for existing and potential new seeps. Inspection activities were performed in accordance with SOC requirements. All locations documented as a seep at issuance of the SOC, as listed in Table 1,with the exception of previously dispositioned seep P-01, were observed and documented with photographs during the inspection (Appendix A). P-01 was not accessible during the inspection due to new fencing and North Carolina Department of Transportation highway projects in the area. The inspection included observations in the following areas: • Along the toe of the 1964 Ash Basin dam • Along the toe of the former 1982 Ash Basin dam • Along the divider dike between the two ash basins • Areas along and downgradient of the 1964 Ash Basin and former 1982 Ash Basin • In the French Broad River floodplain west of Interstate 26. Seep Status Seep locations and inspection areas are shown on Figure 1. Observations noted during the March 2020 inspection are summarized on Table 1. Details of the physical seep inspection include: • No new seeps were observed during the inspection. • No previously unidentified or unreported pipes were observed during inspection. • A 90° V-notch weir was installed at the headwall of the 1964 Ash Basin Seep Collection System for 64E0-01 and 64E0-02, and National Pollutant Discharge Elimination System (NPDES) permitted flow is no longer contained. Head measured above lowest point of weir was recorded at 0.20 feet (approximately 21 gallons per minute) at time of inspection. • Flow was observed emanating from the base of the stormwater dissipation structure north of the former 1982 Ash Basin weirs. Page 2-1 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra • No flow from the pipes within the weirs at the former 1982 Ash Basin was observed. Flow from dissipation structures was at a sufficient volume to back up into the weir boxes. • DD-Pipe was observed flowing overland into adjacent parking lot storm drain. • An Interstate-26 (I-26) widening project is changing Site conditions adjacent to M-01, A-01, A-02, and B-01. • Most wet-weather ditches appeared dry and were not holding water. 2.2 Seep Sampling On April 21-22 and April 28, 2020, SynTerra collected samples for analysis from each seep location identified in the Interim Seep Report (Table 1), except for locations where there were dry or stagnant conditions, insufficient flow, or other observed conditions that would preclude the ability to collect a valid, representative sample as outlined in Duke Energy's March 2016 SOP for seep sampling. Samples were collected in accordance with the March 2016 SOP. Seep sample locations are provided on Figure 1. Seep locations not sampled, along with observations that would preclude the ability to collect a valid, representative sample, are provided below: • 64E0-03—No flow in channel • A-02—Stagnant conditions/No discernible flow • C-03—Insufficient flow to collect representative sample (less than a quarter-inch of depth over PVC pipe barrier) • C-05—No flow in channel • K-02—Seep was dry • SD-01 —Insufficient flow to collect representative sample (less than a quarter- inch of depth over PVC pipe barrier) Individual sampling of seep locations 64E0-01 and 64E0-02 is no longer applicable since these two seeps are now permitted as outfall 101 per the NPDES Permit. It should also be noted that seep locations 82E0-01 and 82E0-02 receive intermittent flow from upgradient stormwater basins. In order to collect representative samples, discharge was suspended from the upgradient stormwater basins for 24 hours and the constructed seep vaults were purged of stored water prior to collecting the samples from those locations on April 28, 2020. Page 2-2 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra In addition, incorrect documentation of pH indicated an abnormally high result in the sample collected from F-02 on April 22, 2020. An additional sample was collected from F-02 on April 28, 2020, to confirm that the prior pH reading was erroneous. Data Results Seep samples collected at the Site in April 2020 were analyzed for parameters listed in Attachment B of the SOC. These data were collected in order to characterize the seep as required by SOC Section 2.b.2. The analytical results, along with a comparison to applicable 02B standards, are included in Table 2. Seep sample locations are provided on Figure 1. It is notable that the pH and mercury concentrations observed in 82E0-01 and 82E0-02 are within the range of groundwater background threshold values (BTVs) for the Site. These BTVs were approved by the Director of the North Carolina Department of Environmental Quality (NCDEQ) Division of Water Resources (DWR) via letter (Zimmerman to Draovitch, October 2017). As such, those concentrations are considered to be naturally occurring rather than effects from CCR material. In addition, acute and chronic 02B standards for select dissolved constituents are hardness-dependent and are calculated based on actual in-stream values as developed and approved by the North Carolina Environmental Management Commission and approved by the United States Environmental Protection Agency (EPA). 15A NCAC 02B .0211 (11)(d) states: "Hardness-dependent freshwater metals standards shall be derived using the equations specified in Table A: Dissolved Freshwater Standards for Hardness- Dependent Metals. If the actual instream hardness (expressed as CaCO3 or Ca+Mg) is less than 400 mg/L, standards shall be calculated based upon the actual instream hardness. If the instream hardness is greater than 400 mg/L, the maximum applicable hardness shall be 400 mg/L." Calculations from Table A in 15A NCAC 02B .0211 (11) (d) were conducted to determine acute and chronic hardness dependent 02B values based on actual in-stream hardness values detected during the April 2020 seep sampling event (Table 3). With the exception of dissolved cadmium in seep N-01, the concentrations of dissolved constituents observed during the April 2020 seep sampling event indicate results less than the applicable 02B standards calculated in Table 3. Page 2-3 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra A review of historical data for N-01 presented in Appendix B indicates that concentrations of constituents that may indicate the presence of CCRs, such as boron, have generally decreased since the seep was first sampled in 2014. These reductions can be attributed to ongoing dewatering of the 1964 Ash Basin that began in 2017, which has reduced the ash basin's effects on seeps in the area. Concentrations of CCR indicator constituents in N-01, with the exception of cadmium, have been either less than the laboratory detection limit or within the approved groundwater BTV range for the Site since November 2018. Further, the most current figures depicting groundwater flow directions and topography in the area of N-01, presented in the Coal Ash Management Act(CAMA) Annual Interim Monitoring Report pertaining to 2018 (SynTerra, 2019) and the Site Study Report-Volume II Site Hydrogeologic Report (Geosyntec, 2019), indicate that N- 01 is side-gradient from the ash basins rather than downgradient. Those figures, presented in Appendix C for reference, do not support that N-01 would be affected by CCR from the ash basins. With the exception of the constituents in seeps mentioned above, and selenium detected in Ponded Water F, no seeps sampled in April 2020 exhibit constituent concentrations greater than applicable 02B standards presented in Table 2 and Table 3. 2.3 Jurisdictional Status of Seeps A jurisdictional determination (JD) (SAW-2014-0189) pertaining to the Site, identifying Waters of the United States (WOTUS), was approved by the U.S. Army Corps of Engineers (USACE) on May 19, 2016. Stream and wetland data derived from the JD are included on Figure 1. SynTerra compared remaining seep locations with the USACE-approved jurisdictional streams and wetlands. Based on this evaluation, all non-dispositioned seeps presented on Table 1 constitute, or flow to, waters of the State or WOTUS with the exception of seep locations C-03, C- 05, 64E0-03, and Ponded Water F. This determination is based on the following: • C-03, C-05, and 64E0-03-no observable flow to identified WOS or WOTUS has been documented during recent inspections. • Ponded Water F is intermittently present and no observable flow to identified WOS or WOTUS has been documented during inspections. Page 2-4 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 2.4 Dispositional Status of Seeps During the March 30, 2020, seep inspection, Mr. Plating inspected each seep to evaluate whether it met requirements to be dispositioned in accordance with the SOC. The requirements for dispositioning a seep are as follows: "For purposes of this Special Order, "dispositioned" includes the following: (1) the seep is dry for at least three consecutive quarters; (2) the seep does not constitute, and does not flow to, waters of the State or Waters of the United States for three consecutive quarters; (3) the seep is no longer impacted by flow from any coal ash basin as determined by the Director of DWR in accord with applicable law and best professional judgment; or (4) the seep has been otherwise eliminated (e.g., through an engineering solution). If a seep that has been dispositioned through drying up reappears in any subsequent survey, such a seep will no longer be deemed dispositioned and can be subsequently re-dispositioned as specified above. Non-constructed seeps described in paragraph 1(h) of this SOC cannot be dispositioned through option (2) above." A discussion of the dispositional status of each seep is provided in the following sections. 2.4.1 Dispositioned No seeps have been dispositioned since the SOC became effective in October 2018. However, several seeps were dispositioned prior to the effective date, as noted in the SOC and on Table 1. These seeps are as follows: • K-02—Evidence of former flow and/or runoff flow. Seep dispositioned because of non-flowing conditions as a result of dewatering the former 1982 Ash Basin. • P-01 —Location previously investigated as a seep. Monitoring has not indicated the presence of CCRs. • SD-01 —Location previously investigated as a seep. Monitoring has not indicated the presence of CCRs. 2.4.2 Non-Dispositioned No seeps have been dispositioned since the SOC became effective. With the exception of K-02, P-01, and SD-01 discussed in Section 2.4.1, all seeps listed on Table 1 are currently considered to be non-dispositioned. Page 2-5 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 2.4.3 Changes of Status An evaluation of seep status changes over time indicates that several seeps documented in Table 1 are considered eligible to be dispositioned based on the SOC requirements for dispositioning. These considerations are based on seep inspections performed on September 4, 2019 (Duke Dam Inspection), December 4, 2019 (Duke Dam Inspection), and March 30, 2020 (SynTerra Interim Seep Inspection). In the terms of the SOC, "dispositioned" includes the following: (1) The seep is dry for at least three consecutive quarters. (2) The seep does not constitute, and does not flow to waters of the State or WOTUS for three consecutive quarters. (3) The seep is no longer impacted by any coal ash basin as determined by the Director of DWR. (4) The seep has otherwise been eliminated (e.g. through an engineering solution). Those seeps requested for dispositioning, along with supporting evidence, are as follows: • C-03 is considered non-jurisdictional and has not flowed to WOS or WOTUS for at least three consecutive quarters-consider dispositioning based on (2) above. • C-05 has been dry for at least three consecutive quarters-consider dispositioning based on (1) above. • 64E0-03 has been dry for at least three consecutive quarters-consider dispositioning based on (1) above. • Ponded Water F is considered non-jurisdictional and has not flowed to WOS or WOTUS for at least three consecutive quarters-consider dispositioning based on (2) above. • Historical concentrations of constituents in N-01 (Appendix B) do not indicate effects of CCR. In addition, figures depicting groundwater flow directions and topography presented in Appendix C do not support that surface water near N-01 would be affected by CCR from the ash basins. 2.5 Decanting/Dewatering/Ash Basin(s) Status Dewatering of the 1982 Ash Basin began in 2007 and was completed in 2016 when the basin was decommissioned. Page 2-6 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Dewatering of the 1964 Ash Basin began in 2017 and is ongoing. Dewatering of the 1964 Ash Basin has produced several notable changes to seep status since the previous inspection: • The saturated area around C-03 appeared to be reduced in size relative to previous inspections, and the area of seepage has migrated approximately 15 feet downslope. • C-05 was dry. • 64E0-03 was dry. 2.6 Ash Basin Closure Status/Corrective Action Plan Excavation of the former 1982 Ash Basin began in 2007 and was completed in September 2016. The footprint of the former 1982 Basin has been re-graded and is now the location of a new combined cycle station. Dewatering and excavation of the 1964 Ash Basin is currently underway. Excavation of the 1964 Ash Basin is anticipated to be complete by 2022 in accordance with Senate Bill 716: Mountain Energy Act of 2015, Section 2 (S.L. 2015-110 §2). A comprehensive site assessment (CSA) of the Site is ongoing, with completion currently scheduled for December 2020. A proposed amendment to the existing corrective action plan (CAP) is planned for submittal by August 31, 2020. This proposed amendment will be prepared to meet the requirements of SOC section 2.b.3 and will be based on the results from this seep characterization report and on subsequent samples, as needed. An updated CAMA required CAP is planned to be prepared for the Site based on findings to be documented in the upcoming CSA. That CAP is anticipated to be completed in 2021 approximately six (6) months after NCDEQ's approval of the CSA pertaining to the Site. Due to select constituent concentrations detected during quarterly monitoring at seep locations E-01 and F-01, short-term remedial actions were undertaken at the Site. These actions include pH adjustment along with supplementary treatment using proprietary stormwater treatment products that are used upgradient of the affected seep locations, as described in the EMC SOC WQ S17-010 Re-Assessment Report (SynTerra, January 2020). Effectiveness monitoring of this short-term remedial action is ongoing. Interim Action Limits (IALs) at these two seep locations are currently being met as a result of these remedial actions. Page 2-7 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 3.0 SEEPS TO BE ADDRESSED Seeps were evaluated based on the physical status, chemical composition, and jurisdictional determination as described in previous sections of this report. In order to be considered for corrective action, a seep must: (1) Be non-dispositioned (2) constitute, or flow to WOS or WOTUS (3) Exhibit constituent concentrations that are greater than applicable 02B surface water standards The evaluation presented in this report indicates that no seep locations listed on Table 1 meet the criteria to be considered for corrective action presented above. • 64E0-01 and 64E0-02-do not exhibit constituent concentrations that are greater than applicable 02B surface water standards. These seeps are also covered as a permitted outfall under the Asheville Plant NPDES permit. • 64E0-03, C-03, C-05, and Ponded Water F-do not constitute, and do not flow to, WOS or WOTUS. • A-01, B-01, C-01, C-02, D-01, E-01, F-01, F-02, F-03, K-01, M-01, 82E0-01, 82E0-02, and DD-Pipe-do not exhibit constituent concentrations that are greater than applicable 02B surface water standards. • A-02-Although recent sample results are not available for A-02, A-02 intermittently flows directly into the A-01 location and would therefore not exhibit constituent concentrations that are greater than applicable 02B surface water standards based on analytical results for A-01. • N-01 -Historical concentrations of constituents in N-01 do not indicate effects of CCR. In addition, figures depicting groundwater flow directions and topography do not support that surface water near N-01 would be affected by CCR from the ash basins. Page 3-1 7 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 4.0 CONCLUSION In accordance with requirements set forth in the SOC, Duke Energy, through its consultant SynTerra, performed an evaluation of seeps downgradient of the ash basins at the Asheville Site for the purpose of characterization of those seeps. This evaluation included: • A physical inspection in March 2020 to identify any new seeps and to document the physical characteristics of previously documented seeps. • An evaluation of April 2020 seep sampling data to determine whether any parameters from Attachment B of the SOC are present in the remaining seeps that have the potential to be considered for corrective action based on comparison with applicable 02B surface water standards or approved Site BTVs. • Review of the USACE-approved jurisdictional streams and wetlands at the Site. Based on the findings from evaluations presented in this report, the following conclusions have been developed: • The March 2020 physical inspection identified three seeps (C-03, C-05, and 64E0-03) that are candidates for dispositioning based on dry or non-flowing conditions observed at these locations for at least three consecutive quarters. • Constructed seeps 64E0-1 and 64E0-2 are covered as a permitted outfall in the Asheville Plant NPDES permit. • A preliminary comparison of April 2020 analytical results with 02B surface water standards identified only two (2) out of 20 sampled locations that had constituent concentrations greater than approved BTV or calculated hardness-dependent 02B surface water standards (N-01 and Ponded Water F). • N-01 analytical data do not indicate that the seep is affected by CCRs from the ash basins and could be considered for dispositioning. • Ponded Water F is non-jurisdictional and has not been observed to flow to waters of the State or WOTUS during at least three consecutive calendar quarters and should be considered for dispositioning. • With concurrence from DWR on seep jurisdictional and dispositional status, it could be determined that corrective action will not be required for any of the remaining seeps identified downgradient of the ash basins at the Site. Page 4-1 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 5.0 REFERENCES Duke Energy (2016). Standard Operating Procedure for Seep Sampling. General Assemblyof North Carolina 2015 . Senate Bill 716:Mountain EnergyAct of2015, ( ) Sec.2:Modifications to Certain Requirements for Coal Ash Management at the Asheville Steam Electric Generating Plant. Geosyntec (2019). Site Study Report—Volume II Site Hydro geological Report, Asheville Steam Electric Plant On-Site CCR Landfill. North Carolina Department of Environmental Quality. (2018). Special Order by Consent EMC SOC WQ S18-005. SynTerra (2019). 2018 Coal Ash Management Act Annual Interim Monitoring Report. SynTerra (2020). 2020 Interim Seep Report. Asheville Steam Electric Plant. Zimmerman to Draovitch (October, 2017).Approval of Provisional Background Threshold Values for Allen Steam Station,Asheville Steam Electric Plant, Buck Combined Cycle Station, Cape Fear Steam Electric Plant, James E. Rogers Energy Complex, Dan River Combined Cycle Station, H.F. Lee Energy Complex, Marshall Steam Station, L.V. Sutton Energy Complex, and W.H. Weatherspoon Power Plant. Page 5-1 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra FIGURES ate,\ �,4.- - '.- ,. _. , ♦♦♦4* - /l .ter i. pptr. aabvv L. ♦ .V: • 1,1 p. • 1 I_s 1 /.{• t, 1 ti f t '•` `� 'l . . ', ,,. . •`-,._ .. • -f \ S` i J �. - R v • �C31 s S, t • a ,---� ,fir' • , iti. It �64E0 3f • 1964 . f __ PROVDED -.' - ASH BASIN r 1Vv47"ER F - ,r , • 1 as • ,. LEGEND 64E0-1/2 :. ir. :. C: ! t m. S - - ` - NHL/ES CONSTRUCTED SEEP(APPROXIMATE) J �. i • CONSTRUCTED SEEP(APPROXIMATE) �C 1 NON-CONSTRUCTED SEEP(APPROXIMATE) DD PIPE 'FORMER 1'• • DISPOSITIONED SEEP(APPROXIMATE) t ASH BASIN ' — G-1 , - 'a 1964ASH BASIN WASTE BOUNDARY ._, i ''« r _ ` ♦ FORMER 1982 ASH BASIN WASTE BOUNDARY \ �` `, �, �~ '� • ` —- DUKE ENERGY PROGRESS PROPERTY LINE ;�.4 `r�. J • . ~ ♦♦ SPECIAL ORDER BY CONSENT(SOC)INSPECTION AREA �1 E-1 r- .74''' ''��•�'! •/ h, " STREAM (TWT 2016) -.4"....+0••A r " - - • v'VETLAND(TWT 2016) ` • 4 ,. l •♦♦♦•♦44) t• '�' Egir ••••• • \ --00.SURFACE WATER FLOW DIRECTION G ��♦ .N.. ,`` ., r' r• NOTES: ': F 1 94 >s, 40♦♦�#44Villfi A '`ate' C! � b .� s 2:y I '^ -'s•-♦♦A•,�t .I'li' ,.:4440et44,- ` I 1.SEEP LOCATIONS ARE DESCRIBED IN EMC SOCWQ S17-010. . )j' "$,1 n R `� ' Ydh�Z -,;.♦®♦♦.�h.'P , /r • r QQQ ♦ r ' ,•,y, ,��♦♦•'¢:` • BFR.;,- - `r • 2.NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM(NPDES)LOCATIONS -' '•` i "" 4«* r"' •l-•�� ARE DESCRIBED IN PERMIT ` .- .. "tip. Gla - • \ „/ P� - ""' - > - . -;. Tf .. NC 0000396. ,. `' _ _ -�. - - � .x; I R�� - STREAMS AND WETLANDS DATA WERE APPROVED BY THE US C16 s ARMY CORPS OF ENGINEERS(USACE ON MAY 19.2016-JURISDICTIONAL ro ;Se " _ - ,y , ♦♦•#.# ♦r ` .. F M - DETERMINATION SAW-2014-00189.TAYLOR WISEMAN AND TAYLOR(TWT) gam• -. fr.'.: 44 \�'�*' .` PERFORMED THE SURVEY OF THE FEATURES - r,, e ®,a a S 4.ALL BOUNDARIES ARE APPROXIMATE. • ' t, t 5.PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY PROGRESS,LLC. 0 OU �.y� '..•.,... > '�^'� ',' ''♦ * _ • • •~ �,-`•.. 6 AERIAL PHOTOGRAPHY OBTAINED FROM NORTH CAROLINA ONE MAP ON -.A t . ; `'%:.,{ />� , "'• •p�. FEBRUARY 20.2020.AERIAL DATED JANUARY 1,2019. + VI •� M f '; - • • SF� 7.DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE '4',N ' - "1" . - o r 1, PLANE COORDINATE SYSTEM FIPS 3200( AD ) :a s _ t ` 7.. Y' ,,. , .. ,. ' - k ...' _�. ,. 300 0 300 600 '� :,. �. ,:, ...' DUKE - if �� a 4 ' �♦ ENERGY GRAPHIC SCALE IN FEET FIGURE 1 SEEP LOCATIONS AND INSPECTION AREAS 4 "+`;-, - - _^` \ ' ' - ,.L,- PROGRESS DRAWN BY:C.DAVIS DATE:03/24/2020 ,_ ,.,,, '.. ,a, h• - REVISED BY:A.ROBINSON DATE:04/14/2020 ROG . 2 SEEP CHARACTERIZATION REPORT VILLE STEAM ELECTRIC P 0 •'y�; S .� b APPROVEDB BY:0BBARRIER DATE:04/16/2020 ARRIER DATE:04/16/2020 ASH ARDEN, NORTH CAROL NALANT '�� syn Terra PROJECT MANAGER:G.BARRIER e Via.. 't:. . . .. f Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra TABLES TABLE 1 SEEP LOCATIONS AND DESCRIPTIONS-MARCH 2020 INSPECTION SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS,LLC,ARDEN,NC Seep ID Location Coordinates Receiving Receiving Facility Number Waterbody Waterbody Description'** SOC Monitoring Interim Action Levels Notes from Inspection Latitude Longitude Classification Easternmost of two engineered drain pipes from 1964 Ash Basin. Became permitted outfall during NPDES permit renewal.Combined NA-Monitoring Water exits from a caged pipe.Flow was observed discharging from UT to French seep flow from 64E0-01,64E0-02,and 64E0-03 is currently being Asheville 64E0-01 35.468319 -82.549104 B Established per Terms See C-01. containment system V-notch weir. Flow was measured at 0.2 feet Broad River monitored by containment system with 90°V-notch weir.Discharge of NPDES Permit above lowest point of weir at time of inspection. flows into UT,through culvert under I-26,into wetland area draining to C-01. Westernmost of two engineered drain pipes from 1964 Ash Basin. Became permitted outfall during NPDES permit renewal.Combined NA-Monitoring Water exits from a caged pipe.Flow was observed discharging from Asheville 64E0-02 35.468319 -82.549104 UT to French B seep flow from 64E0-containment 1, system2,and 64E0-03no is currently being Established per Terms See C-Il. containment system V-notch weir. Flow was measured at 0.2 feet Broad River monitored by containment system with 90°V-notch weir.Discharge of NPDES Permit above lowest point of weir at time of inspection. flows into UT,through culvert under 1-26,into wetland area draining to C-01. Engineered drain from 1964 Ash Basin at black corrugated culvert. Flow infiltrates downstream Into 64E0-01 and 64E0-02 containment UT to French system.Became permitted outfall during NPDES permit renewal. NA-Monitoring Asheville 64E0-03 35.466943 -82.548502 Broad River B Combined seep flow from 64E0-01,64E0-02,and 64E0-03 Is Established per Terms See C-01. No flow.Corrugated pipe to convey flow was dry. currently being monitored by containment system with 90°V-notch of NPDES Permit weir.Discharge flows Into UT,through culvert under 1-26,Into wetland area draining to C-01. Wetlands draining Monitoring at location pH 5-10 S.U. Drainage ditch for collection of seeps and runoff.Water runs under Point of drainage to French Broad River from wetland/braided flow the gravel road via culvert toward the French Broad River. Flow Asheville A-Ol 35.471253 -82.552914 to French B west of 1-26.Northernmost sample locations near river. A-01 prior to entering Mercury 50 ng/L similar to previous inspections.Flow re-enters ground prior to Broad RiverFrench Broad River Selenium 10 pg/L discharge to French Broad River. Wetlands draining Minor seep in wet area just upstream of A-01.Channeled flow drains Monitoring at location Low area that Is completely overgrown with vegetation.Saturated Asheville A-02 35.471155 -82.552596 to French Broad B toward A-al location. A-Ol See A-01 with visible iron staining,but no observable flow. Similar to previous River inspections. Wetlands draining Point of drainage to French Broad River from wetland/braided flow Monitoring at location Mercury 50 ng/L In a ditch that runs parallel to the gravel road,right before the water Asheville 8-01 35.468595 -82.551418 to French Broad B B-01 prior to entering Chlorides 600 mg/L flows into a culvert that runs under the road toward the French Broad west of 1-26.and south of A-01. RiverFrench Broad River TDS 2100 mg/L River.Flow less than previous inspections. Monitoring at location Molybdenum 300 mg/L This seep is located at the end of the gravel road in the floodplain Asheville C-Ol 35.466042 -82.549701 UT to French B Point of drainage to French Broad River from wetland/braided flow C-al prior to entering TDS 1500 mg/L area,adjacent to the wooden footbridge.This area receives water Broad River west of 1-26 and south of B-01. French Broad River Nickel 50 pg/L from D-01 and from a culvert that runs under 1-26 from C-02.Flow similar to previous inspections. Located downstream of the concrete structure at the toe of the 1964 Monitoring location of UT below 1964 Ash Basin for effects of general ash basin dike before entering a culvert under 1-26.This location is Asheville C-02 35.466891 -82.548651 UT to French Monitoring at location B area seepage;site is located just east of culvert under 1-26.Stream See C-Bl now receiving combined flow from 64E0-1,2,&3 as per updated Broad River flow is conveyed into wetland area draining toward C-01 location. C-01 NPDES permit.Flow is more channelized with less algae. Wetlands area very saturated and flowing into C-02. Wetlands area appears to have greater volume of standing water than previous Inspections. Seep near base of northwest side of 1964 Ash Basin.Any flow drains Seep initially collected at Located at the northwest side of the 1964 ash basin between the NA-Monitoring gravel access road and the dike.Seepage noted in toe of slope UT to French to 64E0-3,the 1964 engineered outfall collection system.This non- engineered outfall and Asheville C-03 35.469383 -82.549293 B Established per Terms behind rip rap approximately 10 yards upslope from sign.Seepage Broad River constructed seep flows to a portion of an NPDES wastewater pumped back into basin; of NPDES Permit contained in rip rap lined drainage and conveyed to 64E0-01 and treatment system. afterward,see C-01. 64E0-02. No change since previous inspection. Page 1 of 3 TABLE 1 SEEP LOCATIONS AND DESCRIPTIONS-MARCH 2020 INSPECTION SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS,LLC,ARDEN,NC SeepID Location Coordinates Receiving Receiving Facility Number Waterbody Waterbody Description*** SOC Monitoring Interim Action Levels Notes from Inspection Latitude Longitude Classification AOW near base of northwest side of 1964 Ash Basin.Any flow drains Seep initially collected at Located on the north end of the downstream slope of the 1964 ash NA-Monitoring UT to French to 64E0-3,the 1964 engineered outfall collection system.This non- Established per Terms engineered outfall and basin dam,between C-03 and 64E0-3.Area near C-I5 was dry. Asheville C-05 35.46887 -82.54915 B Broad River constructed seep flows to a portion of an NPDES wastewater pumped back into basin; Minimal water observed in drainage downslope of C-05 sign.Water treatment system. of NPDES Permit afterward,see C-01. within rip rap conveyance from C-03 location. Wetlands draining Located at the end of the gravel road in the floodplain area,near the Seep to established channel within wetlands west of 1-26. Monitoring at location wooden footbridge.This stream Is In a deeply incised ditch and is a Asheville D-Ol 35.465061 -8254944 to French B See C-Ol Channel flows to C-Il location. C-01 tributary to the channel that contains C-Il. Substantial iron staining Broad River visible. Wetlands drainingPoint of drainage to French Broad Monitoringat locationLocated in the floodplain area,about 350 feet down the path south of g pH 5-10 S.U. the footbridge and about 40 feet from the French Broad River. Asheville E-Ol 35.465061 -82.54944 to French B River from wetland/braided flow west E-01 prior to entering Nickel 60 pg/L Channelized flow through low lying area. No standing water Broad River of 1-26 and south of C Il drainage. French Broad River TDS 600 mg/L observed. pH 5-10 S.U. Wetlands draining Point of drainage to French Broad Monitoring at location Copper 15 pg/L Located in the floodplain area,about 950 feet south of the footbridge Asheville F-01 35.463581 -82.54854 to French B River from wetland/braided flow west F-ol prior to entering Mercury 50 ng/L and about 40 feet from the French Broad River.Flow similar to Broad River of I-26 and south of E-01 drainage. French Broad River Nickel 100 pg/L previous inspections. TDS 1000 mg/L Located in the floodplain area,about 1400 feet south of the Wetlands draining Point of drainage to French Broad Monitoring at location footbridge near the right-of-way that crosses the floodplain area.An Asheville F-02 35.462533 -82.547499 to French B River from wetland/braided flow west F-02 pH 5-10 S.U. area of ponded water("Impounded wetland")drains into a channel Broad River of 1-26 and south of F-01 drainage. near the AOW sign and flows through the right-of-way toward the French Broad River.Minimal flow noted exiting the ponded area. Wetlands draining Monitoring location within wetland area west of I-26,at outlet of at location Located about 200 feet northeast of F-02.Flow spreads into wetlands Asheville F-03 35.463114 -82.547177 to French B Monitoring culvert under I-26.May be remnant beaver pond.flows toward F-OS See F-Ol area immediately downgradient from culvert.Flow similar to previous Broad River location,then to French Broad River. F-Ol Inspections. UT to wetlands Monitoring location of UT below the 1982 Ash Basin dam,just east of Located in the ditch adjacent to 1-26,east side,and downgradient of Asheville K-01 35.463051 -82.545751 drainage to B culvert under 1-26,conveying flow to wetlands west of 1-26.Flows Monitoring at location See F-ol AOW 82E0-1&2.Flow Is clear with similar volume to previous French Broad drain through wetlands past locations F-01 Inspections. River F-03 and F-01 before entering French Broad River. Wetlands draining Seep emerging southeast of 1982 basin dam.Any flow would drain NA-Seep Asheville K-02** 35.463581 -82.544577 to French B through wetlands to sampling location F-01 before entering French Dispositioned NA-Seep Dispositioned Evidence of former flow and/or runoff flow.Area is completely dry. Broad River Broad River. Located In the ditch adjacent to I-26,east side,about 500 feet Wetlands draining Monitoring location for coalescence of seep flows prior to entering Monitoring at location farther northwest on I-26.Construction along 1-26 directly adjacent Asheville M-01 35.464266 -82.546712 to French a culvert under 1-26.Flow drains through wetlands to sampling location F-Ol See F-01 to M-01. Ditch to south appears to have been excavated. Check Broad River F-Il before entering French Broad River. dams and other BMPs installed north along I-26 adjacent to M-01. Flow appears similar to previous inspections. Monitoring of UT prior pg/L Located in the low area in the woods east of the gravel road that UT to Powell Cadmium 5 Asheville N-01 35.474088 -82.551532 Creek C Seep to small channel upstream of Its confluence with Powell Creek. to confluence with Mercury 50 ng/L leads to Powell Creek and SD-Il.Monitoring of UT prior to Powell Creek confluence with Powell Creek.No changes since previous Inspection. Page 2 of 3 TABLE 1 SEEP LOCATIONS AND DESCRIPTIONS-MARCH 2020 INSPECTION SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS,LLC,ARDEN,NC Location Coordinates Receiving Facilit Seep ID Number Receiving Waterbody Waterbody Description*** SOC Monitoring Interim Action Levels Notes from Inspection y iving Latitude Longitude Classification UT to the French Monitoring site of small drainage channel south of 1982 ash basin NA-Seep Natural stream cut with sandy and cobble substrate.Could not Asheville P-Ol* 35.46185 -82.544625 Broad River B prior to entering culvert beneath I-26. Dispositioned NA-Seep Dispositloned access P-01 during inspection due to new fencing and highway From sampling-No CCR Impacts. projects. Located in the floodplain area,between B-Ol and A-01,on the west Wetlands draining Asheville Ponded Water F 35.467232 -82.550521 to French B Ponded water near dry channel between locations B-01 and C-01 Monitoring at locations See 8-al and C-OS side of the gravel road.Monitoring at locations B-Ol and C-01. Broad River B-Ol and C-01 Water present in depression similar to previous inspections. 1-26 road construction upstream with substantial clearing noted. HDPE pipe that outfalls onto riprap and drains to Powell Creek.Flow Asheville SD-Ol* 35.474121 -82.552079 Powell Creek C Storm Drain location at north end of site near Powell Creek.From NA-Seep NA-Seep Dispositioned present from corrugated pipe,similar to previous inspections. New sampling-No CCR impacts. Dispositioned stormwater BMPs installed upslope since last inspection,near laydown area. UT to wetlands Western drain(Drain 1)from 1982 ash basin.Basin has been Located in a concrete box outfall structure at the toe of the 1982 ash Asheville 82E0-01 35.464058 -82.544848 .drainage to B excavated and repurposed Any flow would drain to K-Ol and F-Ol Monitoring at location See F-01 basin dike.No flow observed from the pipe.Flow observed emanating French Broad locations. F-01 from the base of the stormwater dissipation structure north of the River 1982 ash basin weirs. UT to wetlands Eastern drain(Drain 2)from 1982 ash basin;east weir.Basin has Located in a concrete box outfall structure at the toe of the 1982 ash Asheville 82 EO-02 35.464058 -82.544848 drainage to B been excavated and repurposed.Any flow would drain to K-Ol and F- Monitoring at location See F-0l basin dike.No flow observed from the pipe.Flow observed emanating, French Broad 01 locations. F-OS from the base of the stormwater dissipation structure north of the River 1982 ash basin weirs. UT to wetlands French drain below divider dike between'64 and past'82 basin.Flow Water flows from 4"PVC pipe located at divider dike. Toe of slope Asheville DD-Pipe 35.466724 -82.544403 drainage to B is into former 1982 basin footprint which was recently removed from Monitoring at location See F-01 saturated with standing water. Seepage drains into parking lot and French Broad the NPDES permit.Flow would drain toward M-Ol location and then to F-Ol stormwater drain just east of seep location. River sample point at F-Ol. Prepared by:060 Checked by:IDP Reim *-Location previously investigated as a seep.Monitonng has not Indicated the presence of coal combustion residuals. **-Seep dispositioned via repair and/or non-flowing condition to potentially reach Waters of the U.S.,or other,as noted. ***-Some descriptions have been updated from the original text found in the SOC Attachment A table for accuracy and currency. UT-Unnamed Tributary pull-micrograms per liter 2B-15A NCAC 02L.0202 Standard CCR-Coal Combustion Residuals mg/L-milligrams per liter NA-Not Applicable ng/L-nanograms per liter NPDES-National Pollutant Discharge Elimination System S.U.-Standard Units SOC-Special Order by Consent TIC-Total Dissolved Solids Page 3 of 3 , 1 i : fl " - - ' . v . , „ , =,, .? ; 11111111121! ;• 11111 111111111111111111111 - - - - - All 111111111111111111111 - - - - -1 inia mommimanion 1 , , , , , ION 1111111111111111111a 1 MI IMEMININE i ' 111111 1111111111111111111111 " - - M0 iiiiiiiiiiiiiiii - 111 - 1 - Mi iiiiiiiiiiiiiiiiiiiii - - - - - OM ' 111111111111111111111 : WIWI " 11111 2EIEEffii El 111111111111111111111 : 111 " E ; ili 11111 111111111111111111111 ,, g11111 1111111111111111111112 " 1 " 1 " E " z " !fli Ali IIIIIIIIIIIIIIIIIIII1 riiiiiigEEE ig 11 111111111111111111111i " Elif " " i 111! II IIIIIIIIIIIIIIIIIIIII " ii1E12iii g 1 i It 1 II 11 111111111111111111111 11111111111 . 1 . 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MI 111111111111111111111 11111111111 11111112111 2 ; . i 11 1 55 ,1irWEE5 RilgiiRRRRR 1 I 1111111111111111111 I IIIIENUMUUMNII 1 - - 1 - EMOMMONNEMEMBE i i i i i i i i i i i , h 1111111111111111111111 ' ' ' ' ' ' ' ' ' ' i ' , . ; i !i UMMODOSHOMOOMO I ' ' ' ' ' ' ' •' ' ' 0 ! i i g! , 1 B i 1 • i i a 1 Oil filD] 0 1 ii 1 , - ,- i .. i i P;:•P ! i i iial ViPiin; W4 I r" . " ' " ' " ' 11 " ! 71 ig ! Onlii ; IM!d1 Hilupo ix ± Irl H101C1Wiflil , fq!AW:ila;:i TABLE 3 COMPARISON OF 02B HARDNESS DEPENDENT STANDARDS SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC,ARDEN, NC Cadmium(Dissolved) Chromium(Dissolved) In-Stream Hardness Value Calculated 02B Calculated 02B Cadmium In-Stream Hardness Value Calculated 02B Calculated 02B Chromium Location ID Hardness Used for 028 Acute Standard Chronic Standard (Dissolved) Location ID Hardness Used for 02B Acute Standard Chronic Standard Calculation Calculation (Dissolved) (mg/L)3 (m9/L)x (p9/L)' (p9/1-)' (p9/L)' (m9/L)3 (m9/L): (p9/L)' (p9/L)' (p9/L)' 64E0-01+02 565 400 9.15 1.20 0.389 64E0-01+02 565 400 1773.30 230.67 <1 82E0-01 114 114 3.07 0.47 <0.1 82E0-01 114 114 634.31 82.51 1.04 82E0-02 94 94 2.60 0.40 <0.1 82E0-02 94 94 541.61 70.45 <1 A-01 78.8 78.8 2.23 0.35 <0.1 A-01 78.8 78.8 468.76 60.98 <1 B-Il 247 247 6.02 0.84 <0.1 8-01 247 247 1194.85 155.43 <1 C-01 555 400 9.15 1.20 0.315 C-01 555 400 1773.30 230.67 <1 C-02 604 400 9.15 1.20 0.546 C-02 604 400 1773.30 230.67 <1 0-01 304 304 7.21 0.98 <0.1 0-01 304 304 1416.34 184.24 <1 E-01 109 109 2.95 0.45 <0.1 E-01 109 109 611.43 79.53 <1 . F-01 116 116 3.12 0.47 <0.1 F-01 116 116 643.41 83.69 <1 F-02 217 217 5.38 0.76 <0.1 F-02 217 217 1074.62 139.79 <1 F-02 226 226 5.57 0.78 <0.1 F-02 226 226 1110.99 144.52 <1 F-03 104 104 2.84 0.44 <0.1 F-03 104 104 588.36 76.53 <1 French Broad Downstream 9.4 9.4 0.35 0.07 <0.1 French Broad Downstream 9.4 9.4 82.16 10.69 <1 French Broad Upstream 9.23 9.23 0.34 0.07 <0.1 French Broad Upstream 9.23 9.23 80.95 10.53 <1 K-01 107 107 2.91 0.45 <0.1 K-01 107 107 602.23 78.34 <1 r M-01 139 139 3.65 0.54 <0.1 M-01 139 139 746.15 97.06 <1 N-01 Downstream* 60.7 60.7 1.77 0.29 `.0.965 N-01 Downstream* 60.7 60.7 378.55 49.24 <1 P-01 28 28 0.90 0.16 <0.1 P-01 28 28 200.87 26.13 <1 Ponded Water F 56.6 56.6 1.67 0.28 <0.1 Ponded Water F 56.6 56.6 357.48 46.50 <1 Separator Dike(DD Pipe) 195 195 4.90 0.70 <0.1 Separator Dike(DD Pipe) 195 195 984.54 128.07 <1 Page 1 of 3 TABLE 3 COMPARISON OF 02B HARDNESS DEPENDENT STANDARDS SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC Copper(Dissolved) Lead(Dissolved) Hardness Value Hardness Value In-Stream Calculated 02B Calculated 02B Copper In-Stream Calculated 02B Calculated 02B Used for 02B Used for 02B Lead(Dissolved) Location ID Hardness Acute Standard Chronic Standard (Dissolved) Location ID Hardness Acute Standard Chronic Standard L(p9/ ) Calculation Calculation ° (m9/L)' (m9/L): (N9/L)' (p9/L)' (N9/L)° (m9/L)' (mg/L)x (N9/L)' (V9/L)' 64E0-01+02 565 400 49.62 29.28 <1 64E0-01+02 565 400 280.85 10.94 <0.2 82E0-01 114 114 15.20 10.02 <1 82E0-01 114 114 74.46 2.90 <0.2 82E0-02 94 94 12.68 8.49 <1 82E0-02 94 94 60.37 2.35 <0.2 A-01 78.8 78.8 10.74 7.31 <1 A-01 78.8 78.8 49.78 1.94 <0.2 B-01 247 247 31.50 19.39 <1 B-01 247 247 170.17 6.63 <0.2 C-01 555 400 49.62 29.28 <1 C-01 555 400 280.85 10.94 <0.2 C-02 604 400 49.62 29.28 <1 C-02 604 400 280.85 10.94 <0.2 D-01 304 304 38.31 23.16 <1 D-01 304 304 211.48 8.24 <0.2 E-01 109 109 14.58 9.64 <1 E-01 109 109 70.93 2.76 <0.2 F-01 116 116 15.46 10.17 <1 F-01 116 116 75.88 2.96 <0.2 F-02 217 217 27.89 17.36 <1 F-02 217 217 148.44 5.78 <0.2 F-02 226 226 28.97 17.98 <1 F-02 226 226 154.95 6.04 <0.2 F-03 104 104 13.95 9.26 <1 F-03 104 104 67.40 2.63 <0.2 French Broad Downstream 9.4 9.4 1.45 1.19 <1 French Broad Downstream 9.4 9.4 4.57 0.18 <0.2 French Broad Upstream 9.23 9.23 1.42 1.17 <1 French Broad Upstream 9.23 9.23 4.48 0.17 <0.2 K-01 107 107 14.32 9.49 <1 K-01 107 107 69.51 2.71 <0.2 M-01 139 139 18.33 11.87 <1 M-01 139 139 92.25 3.60 <0.2 N-01 Downstream* 60.7 60.7 8.40 5.85 <1 N-01 Downstream* 60.7 60.7 37.35 1.46 <0.2 P-Il 28 28 4.05 3.02 <1 P-01 28 28 15.77 0.61 <0.2 Ponded Water F 56.6 56.6 7.86 5.51 1.25 Ponded Water F 56.6 56.6 34.57 1.35 <0.2 Separator Dike(DD Pipe) 195 195 25.21 15.85 <1 Separator Dike(DD Pipe) 195 195 132.53 5.16 <0.2 Page 2 of 3 TABLE 3 COMPARISON OF 02B HARDNESS DEPENDENT STANDARDS SEEP CHARACTERIZATION REPORT ASHEVILLE STEAM ELECTRIC PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC Nickel(Dissolved) Zinc(Dissolved) Hard Value Hardness Value In-Stream Calculated 02B Calculated 02B Nickel In-Stream Calculated 02B Calculated 02B Used for 02B Used for 02B Zinc(Dissolved) Location ID Hardness Acute Standard Chronic Standard (Dissolved) Location ID Hardness Acute Standard Chronic Standard Calculation a i Calculation x (non) (m9/L)' (m0/L)x (119/L) (p9/L)' (pg/L) (m9/L) (my/L): (p9/L)' (p9/L) I 64E0-01+02 565 400 1512.89 168.04 12.5 64E0-01+02 565 400 379.30 382.40 <5 82E0-01 114 114 523.13 58.10 1.51 82E0-01 114 114 130.94 132.01 <5 - 82E0-02 94 94 444.36 49.35 3.12 82E0-02 94 94 111.20 112.10 5.29 A-01 78.8 78.8 382.76 42.51 <1 A-01 78.8 78.8 95.76 96.54 <5 8-01 247 247 1006.20 111.76 1.52 8-01 247 247 252.11 254.17 <5 C-01 555 400 1512.89 168.04 15.8 C-01 555 400 379.30 382.40 8.48 C-02 604 400 1512.89 168.04 21 C-02 604 400 379.30 382.40 6.44 D-01 304 304 1199.43 133.22 <1 0-01 304 304 300.60 303.06 <5 E-01 109 109 503.65 55.94 19.1 E-01 109 109 126.06 127.09 35.4 F-01 116 116 530.88 58.96 22.9 F-01 116 116 132.88 133.97 44.6 F-02 217 217 901.80 100.16 <1 F-02 217 217 225.91 227.76 <5 F-02 226 226 933.34 103.67 <1 F-02 226 226 233.83 235.74 <5 F-03 104 104 484.03 53.76 31 F-03 104 104 121.14 122.13 63.7 French Broad Downstream 9.4 9.4 63.35 7.04 <1 French Broad Downstream 9.4 9.4 15.80 15.93 <5 French Broad Upstream 9.23 9.23 62.38 6.93 <1 French Broad Upstream 9.23 9.23 15.56 15.69 <5 K-01 107 107 495.82 55.07 32.8 K-01 107 107 124.09 125.11 68.2 M-01 139 139 618.66 68.71 1.91 M-01 139 139 154.89 156.16 <5 N-01 Downstream• 60.7 60.7 306.93 34.09 <1 N-01 Downstream* 60.7 60.7 76.76 77.39 5.07 P-01 28 28 159.50 17.72 <1 P-01 28 28 39.85 40.18 <5 Ponded Water F 56.6 56.6 289.30 32.13 1./8 Ponded Water F 56.6 56.6 72.35 72.94 <5 Separator Dike(DD Pipe) 195 195 823.82 91.50 1.4/ Separator Dike(DD Pipe) 195 195 206.35 208.04 <5 Prepared by:GAB Checked by:CUC Notes• ( LBlue highlighted cells indicate April 2020 sample data greater than applicable calculated acute or chronic 02B standard. '-Actual in-stream hardness analytical result from April 2020 sampling event 2-Hardness value used for calculation based on regulation in 15A NCAC 02B.0211(11)(d) '-Calculations for 028 acute and chronic hardness dependent standards were performed in accordance with calculations presented in Table A of 15A NCAC 02B.0211(11)(d) '-Analytical result from April 2020 sampling event *-N-01 nomenclature changed to"N-01 Downstream.'in November 2018. Sample location remains the same as N-01 presented in the SOC. mg/L-milligrams per liter pg/L-micrograms per liter 02B-North Carolina Administrative Code Title 15A,Subchapter 0213-Surface Water and Wetland Standards Page 3 of 3 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra APPENDIX A PHOTOGRAPHS Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Abr • ♦ fi r` AC ;:14•"4:441*-14., '►d_ sz•f*eTS j.; , 1 Ashev 202o 64E0-01 View of the NPDES permitted seep location(facing northeast)looking down. • 5°2R 1 N P. i. • 64 E Asheville 2020 SOC 1 -nark-See,Settings , ••• 30 Mar 2020,11:31:15 64E0-02 View of the NPDES permitted seep location(facing northeast)looking down_ Page 1 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra . __ . 'W(T) • 35'28'6'N,82°32':>5"'W,ie 4ft ♦2088tt z- x 4 i _ . 1 64E0-03 View of NPDES permitted seep location facing southwest. ®86°E(T) `7 35°28'16"N,82°33'10"W±98.4ft ♦2124ft R � far ;' \ Nyr ' —T. I01��.. ' _'. s.-., t e ' r M, ,, -, .. °,,A, ' l' ..i' I r ., E f. •p-trrea 3- .t •V.V.I. )le' 'k% t. F`* Akkte_.,0 -See.. •.,,.c,, A , ,,, & .441.e, A-01 View of SOC sample location facing east. Page 2 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 0 101'E(T) .• 35°2t, ;;fir; F 1 4 t1 • .. , 4010, t 3 Yo,0 W ,,.y 1 `rry iac lttfhgs 30 iar2020, 14.13 2 A-02 View of seep location facing east. O 39°NE(T) *35°28'6"N,82°33'5"W±16.4ft •2034ft w,, AOW s Y . ,::i-_c . 'r. — B-01 View of SOC sample location facing northeast. Page 3 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 0 '. :f- c116. i4` ''W 1•.4f d• I r.,. z; / alc1ni rk Seeale•-Pt:1ys 'r' , ''t't Mar.2G2J,1o:00.58 C-01 View of SOC sample location facing south. 0 176°S(T) •35°28'0"N,.8�-2T°32'54"W±16.4ft •2102ft moo'._ .ram.;. ;,,,,,, - , i _ gj 1 •� w w Y Y Y _�.s lit, 1' C-02 I View of seep location facing south. Page 4 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra • : -)9"N,82°32.57"W t16.4ft ♦2119ft L: LiNSW jr _ s"' 1_;ys, ..arm, !, • Ste. �` ? * 4 ar ' ` IA e is • C-03 View of NPDES permitted seep location facing northeast. 0 66°NE In 4 35°28'7"N,82°32'56"W*16.4ft ♦2116ft � w slk hY } C-05 View of NPDES permitted seep location facing northeast_ Page 5 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra O 23°NE(T) • 35°2/37 N,81'32'58 W w16.4tt ♦2037tt • OATv • D-01 View of seep location facing northeast. c)134°SE(T) *35°27'54"N,82°32'57"W±16.4ft •2027ft eel _ f [.' - — E-01 View of SOC sample location facing southeast. Page 6 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra O 252°W(T) C*35°27'48"N,82°32'54"W±32.8ft •2027ft • yy ti ';09— °x`�!*; • • f Asheville 2020 SOC ti ark- etuny.. 020,15:12:15 View of SOC sample location,facing west.SOC sign in F-01 background. )3°E(T) 11,35°27'45 A 2004tt r 1� A ,J ti � 5�' 42 � �te ' 4 F-02 View of SOC sample location facing east. Page 7 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Yn • -16.4ft ♦2039ft 4 a_' as av, .03 F-0 Ache, le 2020'. Your tt r��Y:�Zi iesti t. F-03 View of seep location facing north. 0 24°NE(T) *35°27'47°N,82°32.44"W±32.8ft A 2049ft * - v. f Via. y : .. .'+ - • 'N( I .'" V.. ,. ; ` `� ' tee.. - 1 "\ Nc_� ►Sala. i ,.j1vo.:.t',,;mark 'ce SetU2, , Q i 1 t,1,:.rc K-01 View of seep location facing northeast. I Page 8 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra • 35°27'48"N,82°32.40"W±16.4ft ♦2051ft w. ; Pam". . . y"' , FO,W, K-02 • ,a .-� � ;�y,. �°t.••..�. - l + � lr '', f1j� yn �.I kA iki, Rl Sl.ti1�i3Yrl't"L`+• - -- --- K-02 View of dispositioned seep location facing east. 080°E(T) #35°27'51"N,82°32'47"W±16.4ft •2052ft ' t ti+ j vp J , - ; . - ,for , . f gvdle t"r L,, M-01 View of seep location facing east. Page 9 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 0 37°NE(T) S 35°28'26"N,82°33'5"W t16.4ft •2042ft • 4`b t 9 -d. i r. - v MX� `'` �µid ,., : !�.-�� ._;t • p i h1_(" N-01 View of SOC sample location facing northeast. I S sw W 0 233°SW(T) •35°2742"N,82.32'40"W±16.4ft •2082ft 14 I, Previous photo(Spring 2019 inspection)of dispositioned seep P-01 location facing southwest.Limited access to seep location due to Plant activities during Spring 2020 inspection. Page 10 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra 0 268°W(T) 35°28'2"N,82°33'1"W±16.4ft ♦2010ft ;(1_, ? •,.0 ".- - . H v mow*, 4. ''. e. \.'r ! Mar'2O _ ,. Cie Ponded Water F View of seep location facing west. 0360°N • 6„N,8 • 554 sy , 4 1 9/ i t t , Ix • Ilk SD-01 View of dispositioned seep location facing north. Page 11 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra e 2ua ��`,`�y, `±am,+'.# ili 1 tv%%I.4,4%4#,,,,,, - ik.c,A. 0„,.. ,4111,.kiti6,444,414414,,A...82 E ti:,,o, 74�«�a vR^ �d1 ' ' a U om« n' S d 1 i ermark §ee '-- rya 82E0-01 View of seep location facing south.% 4 249°W(T) :•35°27'50"N,82°32'41"W±16.4ft ♦2043ft -ar, . • , • .){0 lkik Al -APR '' $ *. II i. ,,ark �'%;» � 4t417 1f''. r S 'R,R.. 82E0-02 Viekv of Seep loiati,,n i_zti.,r; v,t:,; Page 12 of 13 Seep Characterization Report June 2020 Asheville Steam Electric Plant-Duke Energy Progress,LLC SynTerra Q 277°W(T) *35°27'59"N,82°32'38"W±16.4ft A 2140ft 41, Y A, ,' '-#4,,,i, —7 -',"-f-1 '''. , -9'-it ry ? DD-Pipe View of seep location t,u ing xvre-t. Page 13 of 13