Loading...
HomeMy WebLinkAboutNC0000396_SOC_20200317 James Wells DUKE Vice President ENERGY.. Environmental, Health and Safety Programs&Environmental Sciences 526 South Church Street Charlotte,NC 28202 980-373-9646 January 20, 2020 Via Overnight Mail RECEIVED Linda Culpepper, Director MAR 1 7 1020 Division of Water Resources North Carolina Department of Environmental Qualit DDEQ,DWRINPDES 1617 Mail Services Center Raleigh, NC 27699-1617 Subject: Report Under Special Order By Consent (SOC) - EMC SOC WQ S17-010 Duke Energy Progress, LLC - Asheville Steam Electric Plant NPDES Permit NC0000396 Seeps E-01 and F-01 Re-Assessment Report Submittal Dear Ms. Culpepper: On behalf of Duke Energy Progress, LLC (DEP), I am submitting the enclosed report containing the results of a re-assessment of seeps E-01 and F-01 at the Asheville Plant, as required by Section 2(c)(1) of the Asheville Plant SOC No. S17-010. Since the issuance of the SOC, and until the fourth quarter of 2019, these seeps have consistently complied with the SOC's Interim Action Levels (IAL). Following the receipt of the fourth quarter sampling results for E-01 and F-01, a consultant (SynTerra) was contracted to conduct the re-assessment. SynTerra conducted a thorough evaluation including review of groundwater data, surface water data, monitoring of multiple on-site locations, and previous assessments to understand groundwater hydraulics. This effort began in November and is continuing as additional data is obtained. SynTerra's evaluation concluded that there has been an increase in groundwater flow after rock blasting was conducted in order to construct the combined cycle station. The results indicate that the source that lowered the pH is not related to the ash basin operation or coal combustion residual impacts but rather due to either the coal pile and/or naturally occurring pyrites that have been noted in the bedrock. The follow-up sample results in December 2019 resulted in a return to compliance with the IALs for E-01 and F-01. There are several options recommended in the report to improve the groundwater and prevent recurrence. Duke Energy plans to implement several of the recommended options in the very near future. The plan to pump out water from a sediment basin that was determined to contain the lower pH groundwater is ready to proceed once conditions are sufficiently dry. Also, with the recent closing of the coal Ms. Culpepper January 20, 2020 power plant operations the coal pile is scheduled for removal, and subsequent coal yard cleanup is currently planned to be completed in the second quarter of 2020. As required by the SOC, I certify under penalty of law that this document and all attachments were prepared under mydirection or supervision p in accordance with a system designed y es gned 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. Please direct any questions concerning the Asheville Plant NPDES Permit NC0000396 or SOC No. S17-010 to either Robert Wylie at 704 382-4669 or Chris Hallman at 980 373- 7892. Sincerely, Jame Wells { Vice P sident, Environment, Health and Safety Programs and Environmental Sciences Duke Energy Attachment 7t t � synTerra EMC SOC WQ S17-010 RE-ASSESSMENT AT ASHEVILLE STEAM ELECTRIC PLANT 52 NEW ROCKwooD ROAD ARDENT NORTH CAROLINA 28704 JANUARY 2020 PREPARED FOR 4DUKE ENERGY PROGRESS DUKE ENERGY PROGRESS, LLC Chuck Cranford O %NSF .%i'": for Scientist zi SEAL 2 • r ,s o 'lacing, C LG #2410 ,v0`.�9!. 9.'� ���• Project Manager v"',� D. PLP.0``� r SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra TABLE OF CONTENTS SECTION PAGE EXECUTIVE SUMMARY ES-1 1.0 INTRODUCTION 1-1 2.0 RE-ASSESSMENT APPROACH 2-1 3.0 RE-ASSESSMENT ACTIVITIES AND FINDINGS 3-1 3.1 Surface Water Sampling and Data Evaluation 3-1 3.2 Groundwater Sampling and Data Evaluation 3-2 3.3 Precipitation Data 3-4 4.0 INITIAL CONCLUSIONS 4-1 5.0 PROPOSED SHORT-TERM REMEDIAL ACTIONS 5-1 5.1 pH Adjustment 5-1 5.2 pH Adjustment with Supplementary Treatment 5-1 5.3 Groundwater Collection and Treatment 5-2 5.4 Coal Pile Removal 5-2 6.0 REMEDIAL EFFECTIVENESS MONITORING AND REPORTING 6-1 7.0 REFERENCES 7-1 LIST OF TABLES Table 1-1 Monitored Locations and Interim Action Levels Table 3-1 Summary of Analytical Monitoring Results Table 3-2 Low pH Groundwater Wells and Select Constituent Summary Table 3-3 Asheville Airport Rainfall Data LIST OF FIGURES Figure 1-1 Site Layout Figure 1-2 Water Quality Monitoring Locations Figure 3-1 SOC Re-Assessment Sampling Location Map Figure 3-2 Asheville Combined Cycle Station Stormwater System Inspection Figure 3-3 E-01 and F-01 Time Series Plots—pH, Copper, and Nickel Figure 3-4 Coal Pile Area Figure 3-5 E-01 and F-01 Time Series Plots—Boron, Copper, and Nickel Page ii • SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra EXECUTIVE SUMMARY Duke Energy Progress,LLC (Duke Energy) and the North Carolina Environmental Management Commission entered into Special Order By Consent SOC No. S17-010 for the Asheville Steam Electric Plant (Asheville Plant) which was approved on October 10, 2018. Quarterly monitoring results reported on November 22,2019 indicated one analyte (copper) occurred at a concentration 20% greater than the Interim Action Level (IAL) at one monitoring location (F01). Nickel concentrations at E-01 and reduced pH at both E-01 and F-01 were greater than IALs,but less than the 20% threshold that triggers additional assessment. Re-assessment of the contributing seep(s) and an evaluation of proposed remedial actions for treatment and/or control of the seep were promptly initiated upon receipt of the final analytical laboratoryreport. Y Conclusions from the re-assessment include: • Increased concentrations of nickel and copper in recently collected surface water samples from SOC monitoring locations E-01 and F-01 are not related to migration of groundwater affected by ash basin operations to surface water. • Reduced pH and increased nickel and copper concentrations are influenced by the increased groundwater flow that became apparent within the footprint of the former 1982 ash basin after rock blasting related to construction of the combined cycle facility. • Information collected and evaluated to date indicates two possible sources for reduced pH and elevated nickel and copper concentrations: (1) naturally occurring low pH induced by weathering processes of the mineral pyrite contained in bedrock, or (2) downgradient transport of groundwater from an area near the coal pile that exhibits low pH and elevated inorganic constituents. • Analytical results from additional compliance monitoring conducted on December 27, 2019 indicated required monitoring locations identified in the SOC were in compliance with IALs. Potential remedial options identified during the evaluation of corrective actions include: • pH adjustment • pH adjustment with supplemental treatment • Groundwater collection and treatment Page ES-1 • SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra • Coal pile removal Coal power plant operations have recently terminated. Removal of the coal pile is scheduled to be completed during the second quarter of 2020. After source material associated with low pH near the coal pile is removed, natural processes should be effective at mitigating the acidity of the groundwater thereby reducing the mobilization of metals. Page ES-2 a SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 1.0 INTRODUCTION Duke Energy Progress, LLC (Duke Energy) and the North Carolina Environmental Management Commission entered into Special Order By Consent SOC No. S17-010 for the Asheville Steam Electric Plant (Asheville Plant) (Figure 1-1),which was approved on October 10, 2018. Classified waters of the State receiving flow from non-constructed seeps, found in Attachment A of the SOC, are actively monitored and analytical results reported as required at seven (7) seep locations. Interim Action Levels (IALs) were established for select constituents and pH at the monitoring locations. Two additional sample points in the French Broad River (upstream and downstream) are also monitored,but no IALs were established. The constituents that are monitored at each location and IALs are included in Table 1-1. The monitored locations are shown on Figure 1-2. As required by the SOC, 2019 fourth quarter monitoring was completed on November 7, 2019 at the seven required seep locations and the French Broad River locations. Both the Upstream and Downstream French Broad River monitoring locations and seep locations A-01, B-01, C-01, F-02, and N-01 were in compliance with the IALs established in the SOC. One sample at F-01 resulted in a concentration greater than 20% of the IAL (copper, 23.4 µg/L). Additional IAL exceedances: • E-01 nickel: 60.8 µg/L (IAL 60 µg/L) • E-01 pH: 4.1 S.U. (IAL 5-10 S.U.) • F-01 pH: 4.9 S.U. (IAL 5-10 S.U.) Per the SOC, sampling events that resulted in constituents detected at concentrations greater than 20% any interim action level in a single monitoring event, or for two consecutive monitoring events,Duke Energy shall increase to monthly monitoring and conduct a re-assessment of the seeps. This document fulfills the reporting requirement described in section 2. c. Additional Compliance Measures 1) of the SOC: If the monitoring of any classified water of the State receiving flow from seeps regulated by this Special Order indicates exceedance of any interim action level established by the Special Order, Duke Energy shall increase monitoring at that location from quarterly to monthly until concentrations of monitored characteristics return to those observed at the initiation of the Page 1-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra Special Order. If any interim action level established by the Special Order is exceeded by more than 20%in a single sampling event, or exceeded for two (2) consecutive monitoring events, in addition to paying the associated stipulated penalty, Duke Energy shall conduct a re-assessment of the contributing seep(s), including, but not limited to, evaluation of proposed remedial actions for treatment and/or control of the seep such that impacts to the receiving waters are quickly mitigated. A report compiling the findings of the re-assessment, including proposed remedial actions, shall be provided to the Director of DWR within 60 days of any applicable exceedance. Following its review, DWR shall notes Duke Energy of its concurrence or disapproval of Duke Energy's proposed remedial actions. The discharge channels identified as Seeps E-01 and F-01 are located in the floodplain of the French Broad River and convey surface water flows from a wetland/stream complex west of I-26 and the Asheville Plant. Activities for the re-assessment of E-01 and F-01, evaluation of interim remedial actions and proposed short-and long-term corrective actions in pursuit of mitigation are compiled in the remainder of this document. Information collected and evaluated to date indicates two possible sources for reduced pH and elevated nickel and copper concentrations: • Naturally occurring low pH induced by weathering processes of the mineral pyrite containing bedrock matrix after rock blasting related to CC construction. • Downgradient transport of groundwater from an area near the coal pile that exhibits low pH and elevated inorganic constituents. Groundwater from either source is interacting with the stormwater management system associated with the CC facility. Both groundwater and stormwater ultimately flow to the E-01 and F-01 SOC monitoring locations. Page 1-2. SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 2.0 RE-ASSESSMENT APPROACH Planning for the re-assessment of the E-01 and F-01 seeps began on November 22, 2019 after receipt of final laboratory analytical results from the fourth quarter SOC sampling event. Prior to receipt of the final lab report, field work was conducted to further assess the low pH identified in the seeps at E-01 and F-01. The following re-assessment approach was used to evaluate current E-01 and F-01 seep conditions and develop preliminary remedial options to quickly mitigate affects to receiving waters, as required by the SOC. • Conduct site reconnaissance to assess current conditions of the Asheville combined-cycle stormwater collection system, seepage areas and surface waters within the wetland complex downgradient of the former 1982 ash basin and west of Interstate 26 (I-26) • Perform sampling at seep and surface water locations between the combined- cycle stormwater conveyance system and the French Broad River • Review and evaluate historical and current surface water data collected from seeps E-01 and F-01 • Review and evaluate relevant groundwater analytical data • Review and evaluate current and historical, local precipitation data • Develop proposed short- and long-term remedial action strategies to treat and/or control impacted discharges to the seeps • Perform stable isotope evaluation of waters within the Asheville combined-cycle stormwater conveyance system to evaluate water sources within the stormwater conveyance Page 2-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 3.0 RE-ASSESSMENT ACTIVITIES AND FINDINGS Duke Energy and SynTerra staff completed multiple site visits to evaluate current conditions affecting the water quality at E-01 and F-01 and to begin development of remedial options for mitigating the low pH and elevated levels of constituents at the sample locations. Surface water and groundwater samples were collected, visual reconnaissance of the streams and wetlands draining to the subject seep locations was conducted and the newly-constructed, combined-cycle (CC) station's stormwater collection system was evaluated. Stormwater collected within the CC stormwater system flows to the head of the stream channel conveying water to the I-26 culvert. Groundwater emerges at the rip-rap channel along the eastern boundary of the former 1982 ash basin and near the toe of the former 1982 ash basin dam contributing to seep flow (Figure 3-1). These upstream sources of surface water provide the flow at seeps E-01 and F-01. A dry-weather, visual inspection of the stormwater collection system did not reveal any non-stormwater flows associated with the CC station or construction activities. Groundwater infiltration was noted at several manhole locations, identified as MH-021 and MH-022 on Figure 3-2, where the stormwater system discharges to the east stormwater basin(EB) downstream of MH-026. Although identified as a contributing source of groundwater, the approximate one-half gallons per minute flow was considered de minimis. Additional apparent groundwater inputs were identified in two other locations: • The Upper East Channel (UE Channel) - a perimeter, rip-rap-lined ditch bordering the eastern extent of combined-cycle project footprint • Seepage into the EB at a northwestern slope face Construction personnel for the CC station communicated that following the 2017 rock drilling and blasting, associated with construction of the combined-cycle station, groundwater emerged at the surface and was directed to the EB. 3.1 Surface Water Sampling and Data Evaluation A review of the historical AOW and SOC monitoring data indicates the elevated concentrations of nickel and copper under discussion and low pH are recent and isolated. Out of 18 samples collected at E-01 from April 4, 2016 to December 27, 2019, only one sample resulted in a constituent concentration exceeding an IAL: November 7, 2019 result of 60.8 µg/L nickel (nickel IAL 60 µg/L). At F-01, out of 19 samples collected Page 3-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra during the same time period above, only one sample resulted in a concentration of copper exceeding an IAL: November 7,2019 result of 23.4 µg/L copper(copper IAL 15 µg/L). Low pH (<5 S.U.) were measured at E-01 and F-01 in April 2016. The cause of the low pH is unknown. However, it is notable that concentrations of nickel and copper were not substantially elevated during that event. Surface water samples were collected at multiple locations within the stormwater collection system, receiving waters below the former 1982 ash basin, and on the west side of I-26 upstream of seep locations E-01 and F-01. (Figure 3-1). Field parameters were collected during each sampling event at each sample location, and from numerous additional locations to provide data on current conditions of the water features being investigated. Table 3-1 summarizes field parameters and analytical results and Figure 3-1 includes locations and analytical results. Surface water analytical results indicate the following: • Low pH (<5.0)was detected at UE Channel (upstream of the EB) and MH-026 P • Elevated copper and nickel concentrations were identified in samples within the CC stormwater system at the UE Channel, EB Channel, MH-026, and EB Influent and Effluent • Low pH (2.9) was detected in the EB • Low pH (<5.0) and elevated concentrations of copper and nickel were not detected at the west stormwater basin(WB) Historical analytical results show trends of increasing nickel and copper concentrations and lower pH in samples collected from E-01 and F-01 in early 2018 after rock blasting was completed to construct the new CC generating facility. Time series data to visually compare the relationship between pH,nickel and copper are provided in Figure 3-3. 3.2 Groundwater Sampling and Data Evaluation Blasting of bedrock was performed in mid to late 2017 to achieve base grades for the new facility. During the blasting effort,new groundwater flow to the surface within the footprint of the former 1982 ash basin was noted and provides a flow path of groundwater to surface water. Groundwater sampling has been conducted during re-assessment activities and the analytical results are included in Table 3-1. Groundwater analytical results from wells with recent routine low pH (less than 4) are summarized in Table 3-2, and five wells are identified with recent pH values of less than 4 S.U. Page 3-2 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra These wells include: • CB-06 (pH: 3.8-3.9 S.U., n=3) • CPA-04D (pH: 3.3 S.U., n=3) • CPA-04BR (pH: 3.6-3.7 S.U., n=4) • MW-03D (pH: 3.9 S.U., n=1) • MW-05D (pH: 3.6-3.8 S.U., n=5) Hydraulically all five of these wells are considered upgradient of SOC monitoring locations E-01 and F-01 with groundwater flow direction from east to west, toward the French Broad River. However, only the CPA-04D/BR cluster is considered hydraulically upgradient of the groundwater seepage observed within the CC stormwater system (Figure 3-4). Concentrations of nickel and copper measured at the CPA-04 cluster are greater than those observed at E-01, F-01 and the point where groundwater enters the stormwater system (UE Channel). Boron concentrations near the coal pile are less than the 02L standards and generally estimated between 100 and 400 µg/L. Based on hydraulic information and groundwater geochemistry, migration of inorganic constituents downgradient through the fractured bedrock flow system is plausible. However, boron is notably absent from the UE Channel sample and since considered a non-reactive (conservative) constituent that is mobile, the lack of boron at the UE channel may indicate natural processes rather than constituent migration are the primary cause of low pH and elevated constituents. Concentrations of nickel and copper over time do not correlate with the boron, as presented on Figure 3-5. Boron is generally accepted as an indicator of ash basin affected groundwater, and the lack of boron at the UE channel indicates that recently observed elevated constituent concentrations and low pH are not associated with groundwater affected by ash basin operation. Boron concentrations at these surface water locations are decreasing over time with more rapid reduction in concentration after the completion of the 1982 ash basin excavation (end of 2017). Correlation analysis between nickel and boron demonstrate no statistical positive correlation (Spearman correlation—0.6816,n=15; Pearson correlation-0.7345, n=15, P value=0.0018) indicating migration of groundwater affected by ash basin operations is not likely causing the recent and isolated increase observed. Statistical analysis for copper is not possible due to the number of non-detect values in the data set. Page 3-3 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant S nTerra gY Evaluation of oxygen and deuterium isotope results indicated a depleted isotopic signature, similar to the isotopic signature measured in groundwater near the coal pile. 3.3 Precipitation Data Approximately 4 years of regional and local precipitation data from April 2016 through December 2019 was reviewed as part of this re-assessment. Precipitation data collected at the Asheville Regional Airport, approximately 2 miles from the Asheville Station, was acquired from the North Carolina Climate Office (http://climate.ncsu.edu/cronos/?station=KAVL) for evaluation. Normal precipitation records from the National Weather Service (NWS) (https://www.weather.gov/media/ gsp/Climate/AVL/newAVLmonthlyPobs_htm.pdf), were compared to the local data for the time period being considered and indicated below-normal rainfall for the year 2016 —a 26% decrease. The remaining years experienced above-normal precipitation amounts, where increases ranged from 17% in 2017 to 73% in 2018 (Table 3-3). A more detailed review of daily precipitation event records published by the NWS was also completed, particularly of weeks immediately preceding required SOC sampling events. According to data available from the U.S. Drought Monitor (https://droughtmonitor.unl.edu/Maps/MapArchive.aspx), a product produced by the National Drought Mitigation Center, National Oceanic and Atmospheric Administration and United States Department of Agriculture, the Asheville Plant area was not characterized by drought conditions during the time period under review. Precipitation can affect constituent concentrations in surface waters, such as the discharge at E-01 and F-01 through surface runoff and shallow sub-surface flows, particularly during and immediately after precipitation events, due to dilution. As per established protocols, the samples collected for SOC compliance and as part of this re- assessment were collected at times considered representative of normal conditions (e.g., normal flows and low turbidity). Evaluation of sample data and precipitation records did not provide a clear, consistent correlation between the variability of rainfall and changes in concentrations of copper and nickel or pH. The November 7, 2019 and December 27, 2019 sampling events were preceded by similar weekly rain totals: • October 31, 2019 through November 6, 2019—0.76 inches • December 20, 2019 through December 26, 2019— 1.05 inches Page 3-4 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra The rain event prior to the November 7 sample collection occurred on day one of the preceding week and prior to the December 27 sample collection, the rain event occurred on days three and four of the preceding week. The closer proximity and greater total of precipitation to the December sample event could have contributed to the comparatively lower constituent concentrations and slightly increased pH levels to the November sample. Page 3-5 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 4.0 INITIAL CONCLUSIONS Based on the information presented in this report, increased concentrations of nickel and copper and low pH in recently collected surface water samples from SOC monitoring locations E-01 and F-01 do not appear to be related to migration of groundwater affected by ash basin operations to surface water. Elevated concentrations of nickel and copper at E-01 and F-01 are isolated and transient, as indicated by the historical sampling record at these locations. Most recent sampling results collected on December 27, 2019 indicate nickel and copper concentrations less than the IALs and pH values are within an acceptable range. Information collected and evaluated to date indicates two possible sources for reduced pH and elevated nickel and copper concentrations: • Naturally occurring low pH induced by weathering processes of the pyrite containing bedrock matrix after rock blasting related to CC construction. • Downgradient transport of groundwater from the coal pile area that exhibits low pH and elevated inorganic constituents. Groundwater from either source is interacting with the stormwater management system associated with the CC facility. Both groundwater and stormwater ultimately flow to the E-01 and F-01 SOC monitoring locations. Should pH and constituent concentration levels greater than IALs persist, additional evaluation of dynamic geochemical conditions through a PHREEQC model is recommended prior to proceeding with implementation of corrective action strategies. Page 4-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 5.0 PROPOSED SHORT-TERM REMEDIAL ACTIONS Re-assessment activities conducted in accordance with the SOC requirements included evaluation of options for treatment and/or control of the groundwater that is discharging to the CC stormwater system affecting constituent concentrations at E-01 and F-01. Should constituent concentration continue to exceed IALs, the options presented in the following section should be selected and implemented. The following short-term actions were developed to quickly mitigate possible affects to receiving waters. Once the short-term remediation option is selected it will be implemented. Some options may require agency approval. Upon receipt of this approval the selected option will then be implemented. 5.1 pH Adjustment This approach incorporates an in-situ treatment strategy to adjust the pH of the waters present in the east stormwater basin components of the CC stormwater system. Limestone, a basic material,would be added as rip-rap to the existing rock in the conveyance channels (UE Channel and EB Channel) leading to the EB and as#57 gravel at one rock-baffle location within the stormwater basin. These additions would be intended to increase the pH to levels between 5 and 9 and precipitate the copper and nickel as hydroxides, which would settle in the basin. Use of this method could cause iron to precipitate on the surface of the alkaline material and reduce its effectiveness, requiring significant, on-going maintenance. 5.2 pH Adjustment with Supplementary Treatment This approach utilizes the identical option described above with the incorporation of NC DEQ approved PAM/Flocculant products or other proprietary devices, such as sock products for stormwater treatment. The subject products have been utilized across North Carolina, including at Duke Energy sites, to improve stormwater quality. The sock filter media can capture metals and the PAM can improve flocculation of suspended particles and assist with settling and potential removal of metals. Application of these materials can be accomplished by various methods. Additional evaluation and consultation with vendors will be required to determine the applicability of the products and, if considered beneficial, to select the specific product and application method. Page 5-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 5.3 Groundwater Collection and Treatment This approach would utilize either the existing east stormwater basin, a newly constructed sump, or new impounding structure in the UE Channel and installation of pumps to capture and treat the targeted groundwater flow to the CC stormwater system. Options under consideration include: • EB at or near the outlet structure o The existing Faircloth skimmer would be deactivated (i.e., placed above impounded water elevation) to retain normal groundwater base flow in the EB and an electric pump would be installed to deliver water to a temporary holding tank. o Water within the holding tank would periodically be removed and discharged to the lined retention basin for treatment. o During rainfall events, the Faircloth skimmer would be reactivated and pumping would be suspended. o Once the water level in the EB returned to an operational,base flow level, pumping, capture and treatment would resume. • UE Channel above the 60-inch pipe o Either a sump or impounding structure would be constructed to capture normal base flow of groundwater and an electric pump would be installed to deliver water to a temporary holding tank. o Water within the holding tank would periodically be removed and discharged to the lined retention basin for treatment. o During rainfall events, pumping would be suspended and stormflow would bypass the sump or impounding structure. o Once conditions returned to base flow, pumping, capture and treatment would resume. 5.4 Coal Pile Removal Coal operations are scheduled to terminate by January 31, 2020. Following this date, the coal pile, which is thought to be one of the probable sources of the acidic groundwater that mobilizes metals,will no longer be in use. With the recent closing of the coal power plant operations the coal pile is scheduled for removal and subsequent coal yard cleanup is currently planned to be completed in the second quarter of 2020. Page 5-2 • SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra Coal pile removal should be effective in reducing the acidity of the groundwater in that area. After pyritic material associated with the coal pile is removed,natural processes will mitigate the acidity of the groundwater and reduce the mobilization of metals. Page 5-3 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 6.0 REMEDIAL EFFECTIVENESS MONITORING AND REPORTING Following remedy selection and implementation, remedial effectiveness updates will be provided to NCDEQ. Monitoring for effectiveness would vary depending upon the remedy selected. Plans are for the East Sediment Basin's water will be periodically evaluated in comparison to the results of the monitoring at E-01 and F-01. If remedial performance is determined not to be adequate, optimization of existing components and utilization of additional methods would be considered. Modifications or additions to treatment would be implemented and reported in a timely manner. Page 6-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra 7.0 REFERENCES SynTerra (2015). Comprehensive Site Assessment Report—Asheville Steam Electric Pant— August, 2015. Arden, NC. Page 7-1 SOC WQ S17-010 Re-Assessment January 2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra TABLES TABLE 1-1 MONITORED LOCATIONS AND INTERIM ACTION LEVELS SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC Seep ID Number Interim Action Level pH 5-10 S.U. A-01 Mercury 50 ng/L Selenium 10 pg/L Mercury 50 ng/L B-01 Chlorides 600 mg/L TDS 2100 mg/L TDS 1500 mg/L C-01 9/ Nickel 50 pg/L pH 5-10 S.U. E-01 Nickel 60 pg/L TDS 600 mg/L pH 5-10 S.U. Copper 15 pg/L F-01 Mercury 50 ng/L Nickel 100 pg/L TDS 1000 mg/L F-02 pH 5-10 S.U. Cadmium 5 pg/L N-01 Mercury 50 ng/L Upstream and Downstream Monitoring of N/A - 2B Standards Apply the French Broad River Prepared by: CBC Checked by: JPC Notes: pg/L- micrograms per liter mg/L- milligrams per liter ng/L- nanograms per liter S.U.- Standard units TDS -Total Dissolved Solids Page 1 of 1 TABLE 3-1 SUMMARY OF ANALYTICAL MONITORING RESULTS SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC,ARDEN, NC FIELD PARAMETERS SELECTED 40CFR257 APPENDIX III CONSTITUENTS INORGANIC PARAMETERS(TOTAL CONCENTRATION) Specific Dissolved Oxidation Total pH Temp Reduction Eh Turbidity Flow Boron Calcium Chloride Sulfate Dissolved Arsenic Barium Cadmium Chromium Copper Conductance Oxygen Potential Solids Reporting Units S.U. Deg C pmhos/cm mg/L mV mV NTUs GPM pg/L mg/L mg/L mg/L mg/L pg/L pg/L pg/L pg/L pg/L Sample ID Sample Collection Date Analytical Results Analytical Results A-01 11/07/2019 6.2 13 229 5.89 200 405 2.3 9 492 17.9 28 42 135 <1 83 <0,1 <1 <1 B-01 11/07/2019 6.4 14 814 5.30 185 390 5.3 1.5 3410 102 120 180 577 <1 63 0.103 <1 <1 C-01 11/07/2019 6.0 13 1151 5.10 223 428 2.2 NM 3260 163 86 420 910 <1 46 0.458 <1 <1 CB-04 01/02/2020 5.0 14 164 NM NM NM NM NM 207 12.3 NA NA NA <2 69 <2 <2 <2 CB-05 01/02/2020 5.1 11 217 NM NM NM NM NM 212 9.51 NA NA NA <2 32 <2 <2 <2 CB-06 01/02/2020 4.6 10 498 NM NM NM NM NM 410 40.6 NA NA NA <2 45 <2 <2 <2 CB-07 01/02/2020 5.9 11 169 NM NM NM NM NM <50 8.04 NA NA NA <2 11 <2 <2 <2 Confluence 11/20/2019 4.0 11 442 5.99 419 624 4.3 89 193 34.7 8 210 277 5.06 47 0.147 <1 4.92 E-01 11/07/2019 4.1 10 392 7.85 274 479 1.2 39 243 38.1 8.8 150 266 1.66 68 0.311 <1 8.37 E-01 12/27/2019 5.0 8 365 NM NM NM NM 12 310 35 15 140 249 <1 49 0.155 <1 1.47 i E-01 In Process 01/02/2020 4.2 6 378 9.94 147 352 NM NM 333 31.9 NA NA NA <5 44 <5 <5 <5 EB Influent(East Basin) 11/20/2019 3.3 13 679 6.06 568 773 5.6 NM <50 32.1 6.5 280 354 4.92 33 0.179 <1 3.14 EB Channel 12/12/2019 5.8 7 906 NM NM NM NM 5 <50 25.9 NA NA 201 <1 34 <0.1 <1 10.2 EB Effluent 12/12/2019 4.4 8 669 NM NM NM NM NM 76 31.6 NA NA 287 2.79 40 0.111 <1 6.75 EB Effluent 01/02/2020 4.1 7 472 NM NM NM NM NM 107 37.2 NA NA NA <5 39 <5 <5 8.3 EB Seep 01/02/2020 6.0 8 592 NM NM NM NM NM 653 95.8 NA NA NA <5 66 <5 <5 <5 F-01 11/07/2019 4.9 10 367 8.29 221 426 6.3 92 234 35.4 7.2 150 271 6.25 90 0.195 2.35 23.4 F-01 12/27/2019 5.2 8 380 NM NM NM NM NM 323 37.3 11 160 267 2.93 52 0.112 <1 4.39 French Broad Downstream 11/07/2019 6.5 13 47 6.65 185 390 7.0 NM <50 2.91 2.2 2.1 25 <1 14 <0.1 <1 <1 French Broad Upstream 11/07/2019 5.9 11 36 9.00 174 379 7.0 NM <50 2.87 2.2 1.8 31 <1 14 <0.1 <1 <1 I-26 Culvert 11/20/2019 4.7 11 410 6.40 387 592 3.1 90 355 35.3 8.2 190 278 3.92 58 0.143 <1 3.56 MH-026 12/12/2019 4.9 11 873 NM NM NM NM 0.5 <50 25.1 NA NA 308 3.02 40 0.19 <1 4.93 Page 1 of 4 • TABLE 3-1 SUMMARY OF ANALYTICAL MONITORING RESULTS SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS,LLC,ARDEN, NC INORGANIC PARAMETERS(TOTAL CONCENTRATION) INORGANIC PARAMETERS(DISSOLVED CONCENTRATION WITH FILTER SIZE) OTHER PARAMETERS Nitrate+ Arsenic Cadmium Chromium Copper Lead Nickel Zinc Lead Magnesium Mercury Nickel Nitrite Selenium Thallium Zinc Bromide Fluoride Hardness (0.45u) (0.45u) (0.45u) (0.45u) (O.45u) (O.45u) (0.45u) Reporting Units pg/L mg/L pg/L pg/L mg-N/l pg/L pg/L pg/L Ng/L pg/L Ng/L pg/L WI pg/L pg/L pg/L mg/L mg/L Sample ID Sample Collection Date Analytical Results A-Ol 11/07/2019 <0.2 7.94 0.00695 <1 0.74 1.43 <0.2 <5 <1 <0.1 <1 <1 <0.2 <1 <5 120 <0.1 77.4 B-01 11/07/2019 <0.2 30.2 0.00386 4.77 0.33 <1 <0.2 9.78 <1 0.108 <1 <1 <0.2 4.43 8.93 780 <0.5 380 C-al 11/07/2019 <0.2 53 0.00285 23.6 0.44 <1 <0.2 14.4 <1 0.443 <1 <1 <0.2 23.3 13.8 1100 <1 626 CB-04 01/02/2020 <0.4 2.67 NA <2 NA 3.02 <0.4 <10 NA NA NA NA NA NA NA NA NA 41.6 CB-05 01/02/2020 <0.4 5.59 NA <2 NA <2 <0.4 <10 NA NA NA NA NA NA NA NA NA 46.7 CB-06 01/02/2020 <0.4 7.36 NA 12.6 NA <2 <0.4 <10 NA NA NA NA NA NA NA NA NA 132 CB-07 01/02/2020 <0.4 2.13 NA <2 NA 9.07 <0.4 <10 NA NA NA NA NA NA NA NA NA 28.9 Confluence 11/20/2019 1.37 11.8 0.00634 71.3 0.54 <1 <0.2 153 5.07 0.14 <1 5.03 1.27 72 150 130 0.5 135 E-01 11/07/2019 <0.2 11 <0.0005 60.8 0.29 <1 <0.2 146 1.68 0.352 <1 8.67 <0.2 61 147 <100 0.38 141 E-01 12/27/2019 <0.2 10.6 <0.0005 33.6 0.39 <1 <0.2 75.1 <1 0.176 <1 1.46 <0.2 33.5 74.8 <200 0.3 131 E-01 In Process 01/02/2020 <1 10.6 NA 27.5 NA <5 <1 65.8 NA NA NA NA NA NA NA NA NA 123 EB Influent(East Basin) 11/20/2019 2.23 12.7 0.0029 103 0.5 1.15 <0.2 196 5.03 0.157 <1 3.51 2.18 105 200 <100 0.65 132 EB Channel 12/12/2019 <0.2 7.28 NA 31.2 NA <1 <0.2 26.9 NA NA NA NA NA NA NA NA NA 94.6 EB Effluent 12/12/2019 0.991 9.36 NA 67.8 NA <1 <0.2 141 NA NA NA NA NA NA NA NA NA 117 EB Effluent 01/02/2020 1.27 12.4 NA 102 NA <5 <1 188 NA NA NA NA NA NA NA NA NA 144 EB Seep 01/02/2020 1.93 15.3 NA <5 NA <5 <1 32 NA NA NA NA NA NA NA NA NA 302 F-01 11/07/2019 2.92 11.7 0.000973 70.6 0.36 3.15 <0.2 159 3.99 0.214 <1 17.2 0.267 67.9 152 <500 <0.5 137 F-01 12/27/2019 0.266 12.3 0.000804 39.1 0.63 1.19 <0.2 75.4 2.62 0.106 <1 2.58 <0.2 38.3 73.5 <500 <0.5 144 French Broad Downstream 11/07/2019 0.258 0.99 0.00224 <1 0.32 <1 <0.2 <5 <1 <0.1 <1 <1 <0.2 <1 <5 <100 <0.1 11.3 French Broad Upstream 11/07/2019 0.279 0.981 0.00207 <1 0.31 <1 <0.2 <5 <1 <0.1 <1 <1 <0.2 <1 <5 <100 <0.1 11.2 1-26 Culvert 11/20/2019 0.717 12 0.00237 47.9 0.49 <1 <0.2 105 3.1 0.229 <1 3.5 0.51 48.9 104 160 0.35 138 1 MH-026 12/12/2019 0.713 9.46 NA 98.6 NA <1 <0.2 199 NA NA NA NA NA NA NA I NA NA 102 Page 2 of 4 TABLE 3-1 SUMMARY OF ANALYTICAL MONITORING RESULTS SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC,ARDEN, NC FIELD PARAMETERS SELECTED 4OCFR257 APPENDIX III CONSTITUENTS INORGANIC PARAMETERS(TOTAL CONCENTRATION) Specific Dissolved Oxidation Total • pH Temp Reduction Eh Turbidity Flow Boron Calcium Chloride Sulfate Dissolved Arsenic Barium Cadmium Chromium Copper Conductance Oxygen Potential Solids - Reporting Units S.U. Deg C pmhos/cm mg/L mV mV NTUs GPM pg/L mg/L mg/L mg/L mg/L pg/L pg/L pg/L pg/L pg/L Sample ID Sample Analytical Results Analytical Results Collection Date MH-026 01/02/2020 3.6 12 770 NM NM NM NM NM <50 36.1 NA NA NA 9.36 37 <5 <5 9.63 I N-01 Downstream 11/07/2019 6.8 10 158 7.90 143 348 5.8 75 <50 15.4 5 38 104 <1 27 1.5 <1 <1 Ponded Water F 11/07/2019 6.6 9 222 2.11 200 405 4.8 NM 281 20.3 25 34 160 4 64 0.168 <1 3.02 UE Channel 01/02/2020 2.9 7 1137 NM NM NM NM NM <50 20.3 NA NA NA <5 21 <5 13.3 428 WB Effluent(West Basin) 11/20/2019 8.9 9 198 8.67 228 433 60.1 NM 56 19.4 16 31 92 <1 17 <0.1 2.04 2.21 Maus: ----Not applicable <-Concentration not detected at or above the adjusted reporting limit. pg/L-Micrograms per liter pmhos/cm pmhos/cm-Mico mhos per centimeter Deg C-Degrees Celsius Dup-Duplicate EB-East Basin ft-feet GPM-Gallons per minute Hg-Mercury mg/L-milligrams per liter mg-N/L-milligrams Nitrogen per liter MH-Manhole mV-millivolts NA-Not analyzed NE-Not established NM-Not measured NTUs-Nephelometric Turbidity Units S.U.-Standard units Temp-temperature UE-Upper East Page 3 of 4 TABLE 3-1 SUMMARY OF ANALYTICAL MONITORING RESULTS SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC INORGANIC PARAMETERS(TOTAL CONCENTRATION) INORGANIC PARAMETERS(DISSOLVED CONCENTRATION WITH FILTER SIZE) OTHER PARAMETERS Nitrate+ Arsenic Cadmium Chromium Copper Lead Nickel Zinc Lead Magnesium Mercury Nickel Nitrite Selenium Thallium Zinc Bromide Fluoride Hardness (0.45u) (0.45u) (0.45u) (0.45u) (0.45u) (0.45u) (0.45u) Reporting Units pg/L mg/L pg/L pg/L mg-N/L pg/L P9/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L mg/L Sample ID Sample Collection Date Analytical Results MH-026 01/02/2020 1.46 19 NA 235 NA <5 <1 465 NA NA NA NA NA NA NA NA NA 169 • N-01 Downstream 11/07/2019 <0.2 5.85 0.00248 <1 0.33 <1 <0.2 10.5 <1 0.957 <1 <1 <0.2 <1 10.9 <100 <0.1 62.7 Ponded Water F 11/07/2019 <0.2 5.94 <0.005 3.28 0.79 30.2 0.266 13 3.69 0.156 <1 1.96 <0.2 2.98 11.4 <100 <0.1 75 UE Channel 01/02/2020 <1 17 NA 308 NA <5 <1 291 NA NA NA NA NA NA NA NA NA 121 WB Effluent(West Basin) 11/20/2019 0.386 4.34 0.00101 1.23 0.13 <1 <0.2 18.2 <1 <0.1 1.7 1.24 <0.2 <1 <5 120 0 23 66.3 Prepared by:$gR Checked by:IE Notes ----Not applicable <-Concentration not detected at or above the adjusted reporting limit. pg/L-Micrograms per liter pmhos/cm pmhos/cm-Mico mhos per centimeter Deg C-Degrees Celsius Dup-Duplicate EB-East Basin ft-feet GPM-Gallons per minute Mg-Mercury mg/L-milligrams per liter mg-N/L-milligrams Nitrogen per liter MI-I-Manhole mV-millivolts NA-Not analyzed NE-Not established NM-Not measured NTUs-Nephelometric Turbidity Units S.U.-Standard units Temp-temperature UE-Upper East Page 4 of 4 TABLE 3-2 LOW pH GROUNDWATER WELLS AND SELECT CONSTITUENT SUMMARY SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC Analytical Parameter pH Boron Copper Nickel Reporting Units S.U. pg/L pg/L pg/L • 1SA NCAC 02L Standard 6.5-8.5 700 1000 100 Provisional Background(Alluvial Unit) 4.6-5.1 50 5 5 Provisional Background(Saprolite Unit) 4.3-5.8 50 5 10 Provisional Background(Transition Unit) 3.9-7.0 50 2.08 9.825 Provisional Background(Bedrock Unit) 4.1-8.1 50 1 1.77 Sample Sample ID Analytical Results Collection Date ABMW-025 09/01/2015 3.9 NA Na B-01 CCR 06/14/2017 3.1 _ NIX NA CB-06 11/04/2015 3.4 802 75 CB-06 12/08/2015 3.5 700 38.5 CB-06 01/21/2016 3.6 599 <1 18.7 CB-06 04/06/2016 3.7 576 <5 18 CB-06 01/31/2017 3.9 667 1.26 78.9 CB-06 04/06/2017 3.7 628 <5 72 CB-06 07/07/2017 3.9 710 <5 54 CB-06 11/01/2017 3.8 632 <5 23 CB-06 11/29/2017 3.7 NA NA NA CB-06 CAMA 04/06/2017 3.7 670 1.08 41.4 CB-06 IMP 07/07/2017 3.9 741 <1 42.6 CB-06 IMP 11/01/2017 3.8 624 <1 22.6 CB-06 02/08/2018 3.9 444 <1 14 CB-06 04/17/2018 3.8 451 <5 17 CB-06 IMP 04/17/2018 3.8 477 1.2 14 CPA-04BR 01/29/2019 3.6 198.76j 378 8580 CPA-048R 04/16/2019 3.7 179.061j 211 9720 CPA-04BR I 07/23/2019 3.7 176.2 j 417 8590 CPA-0489 10/17/2019 3.7 148.786j 325 9800 CPA-040 01/29/2019 3.3 375.946j 921 6000 CPA-040 04/16/2019 3.3 354.857j 941 6010 CPA-040 07/23/2019 3.3 370.3 j 1320 7160 GW-01 04/21/2008 3.8 <10 <5 GW-01 05/11/2010 3.1 <50 <5 5 MW-03D 10/26/2017 3.9 NA NA N= MW-03D CCR _ 01/24/2019 3.9 346 NA NA MW-05D 09/02/2015 3.6 NA NA NA. MW-05D 01/27/2017 3.8 634 13.3 34.% MW-050 04/04/2017 3.7 627 13.3 21.9 MW-050 07/18/2017 3.7 640 13.9 18.1 'IW-05D 10/26/2017 3.9 706 13.2 18 MW-050 04/18/2018 3.7 661 12.4 13.7 MW-050 07/11/2018 3.6 672 9.55 11.3 MW-050 11/07/2018 3.8 694 5.66 17.2 MW-05D 04/17/2019 3.7 602 NA 13.3 MW-050 07/24/2019 3.6 652 NA 16.9 MW-050 10/18/2019 3.8 670 NA 24.2 PZ-17S CCR 5</14/2017 3-8 <50 t." '." I Prepared by:CBC Checked by:)PC TEXT:Indicates samples collected prior to January 1,2018 I I -Bold highlighted concentration indicates exceedance of the 15A NCAC 02L.0202 Standard or the IMAC. (Effective date for 15A NCAC 02L.0202 Standard and IMAC Is April 1,2013) <-concentration not detected at or above the adjusted reporting limit. pg/L-micrograms per liter CAMA-Coal Ash Management Act CCR-Coal combustion residuals CPA-Coal Pile Area IMP-Interim Monitoring Program j-Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. NA-not applicable S.U.-Standard units SOC-Special Order by Consent Page lof1 I TABLE 3-3 ASHEVILLE AIRPORT RAINFALL DATA SOC WQ S17-010 RE-ASSESSMENT ASHEVILLE PLANT DUKE ENERGY PROGRESS, LLC, ARDEN, NC Total Year Normal Percentage Annual Inches Annual Inches Difference 2016 33.45 45.47 -26% • 2017 53.20 45.47 17% 2018 78.46 45.47 73% 2019 56.77 45.47 25% Prepared by: CBC Checked by: JPC Notes: - percent Sources: https://www.weather.govigsp/avIcli http://climate.ncsu.edu/cronos/?station=KAVL Page 1of1 SOC WQS17-010 Re-Assessment January2020 Duke Energy Progress,LLC,Asheville Steam Electric Plant SynTerra FIGURES "\ �..fr_ ,.r � LAKE , A.: _ ' r7.. - ULIAN , ,� r •I I } ,, emu` ,` `' L, a . s J f �'y,� $ . r y J- r f \ v.,,,,teri,:. -, '' -.-,,,,,z...,..,,,„4,A,),,,,,,,,,,,„,,,, r' „JAL- COAL PILE '4', . 12, - LAKE JULIAN \ , ,, \ • r2. l i--'---- 11964 ASH BASK \ , „ ... i N FORMER 1982 ASH BASIN � �, � \ , -I. _4* , _ ASHEVILLE COMBINED CYCLE STATION "\ / .t141:' -\ 40 'WEST STORM WATER BASIN;n, ' s, / „� S' LAST STORM WATER BASIN] . �� \.. , . 0 < \ .... 13.. • ‘• -- 7 , - \ . \ ..,. ., .... ... , ....___ ,..„,...., ... N. _ LEGEND DUKE ENERGY PROGRESS PROPERTY LINE - WETLAND AREAS(APPROXIMATE) SOURCE: MARCH 6,2019 AERIAL Ph0'OGRAPH OBTAINED FROM NC ONE MAP GEOSPATIAL PORTAL AT' SURFACE WATER FLOW(APPROXIMATE) http://0ata.monemap.com/geoportal/catalogiraster/00wnloacIpage ' GRAPHIC SCALE �ENERGY DUKE 250 0 250 500 IN FEET FIGURE 1-1 PROGRESS DRAWN BY:J.CHASTAIN DATE:1/17/2020 SITE LAYOUT REVISED BY:- DATE:- CHECKED BY:C.CRANFORDAPPROV DATE1/17/2020 ASHEVILLE PLANT PROJECT MANAGER: T.PLATING DATE:1/17/2020 ARDEN, NORTH CAROLINA PROJECT MANAGER:T.PLATING synTerra www.synterracorp.com \ �, ) \ , �N�, r Ni❑FRENCH BROAD-DOWNSTREAM .; 1 -_�. \ s \0 , \ \ \ .,".,'' -MANE JUIIAN \ (' �� \ \ \ \ .+ - ' S. - 14 4 \\ \ _ ' 1 i o '1964 ASH BASIN - S -.�. ._ \ HEVILLE COMBINED` i` .CYCLE STATION �^ i ' '' a T ' r- • . INtt o FORMER 198 ASH BASIN \ /7'. \ 1....../.--. \ \ \ \ \:),,, F 0:1j , .•...- \ -F Q2' \, \ 1---........ LEGEND \ i OH C,. SOC ROUTINE SAMPLE LOCATION ®upsTRE / FRENCe AM BROAD.FRENCH BROAD RIVER SAMPLE LOCATION(APPROXIMATE) ❑FRENCH BROAD-UPSTREAM r /+,�� at ——— DUKE ENERGY PROGRESS PROPERTY LINE (�DUKE „r<ar,_r 5 63 600 `C ENERGY Nrfl FIGURE 1-2 PROGRESS °,,WNW, r. CM._L17/aom WATER QUALITY MONITORING LOCATIONS DM 0 `eS`a o w oNo EWE.v„aozo ASHEVILLE PLANT APPROVEDen PROXOt GER-7 RATING TI wrz.v-n2. ARDEN,NORTH CAROLINA - - synTena Y/WN,.synterracorp.corn • • � ` r - � ' 11 r am '- f + ' _ � _ \ - if-,-, •.-- .. ‘, - .yam _ if .. t .Rv� \ ,.. tl- , r . A 200 12.1 • *- - F I ` CB-7 B 1 J • ': TOTALCOPPER.{.93Vp1L 0 7 % -I '�,� .. DATE 2020-01-02 �� r—! TOTAL NICKEL•00 620/L s pH•5.9 S.U. DATE B 20-01-03 •'A•?TOTA L COPPER.<219A - TOTAL COPPER•9.6]YpOL / f 1 1± TOTAL NICKEL=<2V9/L I •` pA-1020� TOTAL MICKEL.2]NWL ,.. }. `. f I pR�,� � TOTAL coPPER-<spyL UE CHANNEL �yArm �+TOTAL NICKEL•OS , /% DATE 3020-01-03 \ A,74P. 9 S U \ ' P4 3�AR+Y �,y,�y, ( • 1/ TOTAL COPPER•126V9/... # /y. T i•! f { z OTAL NICKEL•306Vo L CB-6 _) WEST BASINIWS EFFLUENT ys.X INFLUENT ±+T_-.- _ i-02 DATE2M9-11-20 9 -+ "`'i '/ .{.BSU PH.6J6.U. r� �]BU.ER•].t{yyl $ OTAL COPPER•t]1Pyl < { E-01 TOTAL COPPER•<2V9/L ';d} TOTAL NICKEL a 1.23VyL ,, h TOTAL NICKEL•10]VyL .^•..a. 15Kit-20191147 -"- TOTAL NICKEL.126Y9,L 1y.1 .L_,. pH...1 S.0 \O . TOTAL COPPER•9.37V07L ? T - P, .h'it, y s.1+yf --t • B �` .... hc1 LNICKEL•90.WpIL ` `N NUNCE /� A2 `^ , ■aIt6yp/L ‘ TOTAL COPPER•{921NPL `' \ • 'A,,,,,, tA, - N\ • .. - TOTAL NICKEL•),]yplL ■ ,,�`'.c yt .. I \ pH s8U . vim < � - ITOTAL COPPER.102VpM1 "' F-01 NICKEL 31 DATE 1019.1147 '`' TOTAL COPPER.23App&E - I N. •' y, ' - '1 TOTAL NMIEFI•70 DAOL/ EAST BASIN/EB EFFLUENT" - J,/ • DATE 2019-12-27 DATE 2019-11-20 i oD-T '' 11 - pH.52SU. ^pN.{A B.U. TOTAL COPPER•4.29,0E ' TOTAL COPPER.6.15000E p� N••�_ _ TOTAL NICKEL•1p LM TOTAL NICKEL•67.809/L % + � A .} pb \ DATE 3020-01-1e -, .,, I \ •TOTALICOPPER.e.]V9R ' TOTAL NICKEL•1021�9/L t`\ ` r i QQ11 CB-4 ` , � GATE 3020-01-02 \ — 5 `\\\ `yTOTAL COPPER•O04L v I TOTAL NICKEL•<LyyL . �T LEGEND \ t \�� ■(EB CHANNEL]SOC RE-ASSESSMENT SAMPLE LOCATION(APPROXIMATE) - 1 O® SOC ROUTINE SAMPLE LOCATION J@flCD 4) MONITORING WELL . / --- DUKE ENERGY PROGRESS PROPERTY LINE DATE 3010-0 N. TN• P. \ WETLAND AREAS(APPROXIMATE) TOTALL COOPPER.2pg/L c 1 TOTAL MCKEE.. 2p9A *. I. c(.DUKE 20o— —SURFACE WATER FLOW(APPROXIMATE) •RAPHIC SCAI _-;o N`zoo aoo i ENERGY FIGURE 3-1 ,.. PROGRESS DRAWN BY ,,°H ABN DATE 1/1772020 SOC RE-ASSESSMENT SAMPLING DATA REVI0E0 CHECKED BY C.CRANFORD DATE TE :1/17/2020 ASHEVILLE PLANT a 0 APPROVED EA C.ORAPPORD PROJECTMANAGER,, G. °i Y1 0 0 ARDEN,NORTH CAROLINA �S'OURCE: NAP;I9•I: mapPHOTOGRAPH E�:bBv:,;:.°70"=�E.E:DED oA. PORTAL AT synTena v u www.s nterracor .com Asheville Combined Cycle .i ____7_ Stormwater System Inspection W O16 w-ct2 MN-016 December 12,2019 MH-017 �� • Minimal standing water I ORME YID • Minimal standing water S.Q v 1 • No seepage evident 153, • No seepage evident__ Hoar autM SEE owAt NOW 3 __ " / ipmare , SEE NOW 3 'a - MH-018 � MY ORM -`T • Minimal standing water SEE unit 3 _ 7 ...1 No seepage evident lid } Nf106.00 1 ,' fir � f 11lt.00 MH-022 MH-020 • Minimal flow through manhole \ /- Mom RIzrer,--` �'`- 1 • Minimal standing water • Seepage evident around inlet pipe , sEE NotE }1 OF No seepage evident w-ein MH 023 RO ROTE YI-Cd2 MH-021 • Minimal flow through manhole • Minimal flow through manhole \\ • Seepage evident around inlet pipe • No seepage evident i w-es ,� MH-024 i MH-025 • Minimal flow through manhole • Minimal flow through manhole 4 • No seepage evident I • No seepage evident 4 SU aM15 AOCOa-Cr-C-CR-PL-M a-06 �� .1 i ���' ,AAH-026 / 1 a i Samples were collected for East ' isotopes,metals and TDS(Sample Stormwater ' ID:MH-026) Basin '� pH-4.925U % pH-3.31 SU ' - • P Temperature-10.8`C e/�; �' ''Q- Specific conductance-873 µ5/cm '`=z�r ' Turbidity-5,57 NTU Rv-OF 1 ; - %'y Flow-0.5 gpm(measured via a 7-- or'r container and stopwatch) ,, LEGEND 410., DUKE DRAWN BY C CRANFORDDATE 1/8/2020 C-Degrees Celsius ENERGY REVISED BY: K.SHECK FIGURE 3-2 pS/cm-micro-Siemens per centimeter CHECKED BY:T.PLATING ASHEVILLE COMBINED CYCLE STATION gpm-gallons per minute PROGRESS APPROVED BY: T.PLATING STORMWATER SYSTEM INSPECTION MN-Manhole PROJECT MANAGER:G.BARRIER NTU-Nephelometric Turbidity Units SOC WQ S17-010 RE-ASSESSMENT SU-Standard Units `' ASHEVILLE PLANT TDS-TotalDissolvedSolids ARDEN, NORTH CAROLINA SylnTerra www.synterracorp.com Source:CB&I Drawing No.ACCOO-CV-C-SO.PL-202 E-01 70 . 7.0 60 I :: 6.0 v C 5.0 "2 —0—Nickel o c c30 --*—Copper a) _ V.,• 20 a pH 4.0 0 U T 10 0 ,_ _ .f ,_ _ _. - 3.0 1 �O/�3/�01 i1�i�016 6�1/�0�, �10/�OT� �i70 J�/�019 9��6/.-30 S F-01 70 -____ ________j___ __ __ _ 7.0 "...—a60 —_� _1 II __._ y c - 6.0 a) 40 _ i - -a —0—Nickel o - v - m v 30 = Copper PH c 20 ._ 5.0 0 v 10 0 116 t _ i 4.0 zOi biz --- /T 7/A j�/ 9/, �Si�01S 8��016 i20r, 0��0TS /�019 djvIO 6�T020 LEGEND DUKE DRAWN BY:T.PLATING DATE:1/2020 pg/L-micrograms .� rams per EN ERGY REVISED BY: K.SHECK FIGURE l `-C,RESS TIME SERIES liter CHECKED BY: E-01 AND F-01 PLOTS—pH, COPPER, AND NICKEL APPROVED BY: PROJECT MANAGER:G.BARRIER SOC WQ S17-010 RE-ASSESSMENT ' ASHEVILLE PLANT SyClI u id www.synterracorp.com ARDEN, NORTH CAROLINA P F ' l rV• 4-" ar ..�. r Ad fdd F rt IO iri " .mod �- , r • '� P X �: ,` - I \ r n . r 7** (( r ' - '"0"1` CPA 1DI — F' , CPA-1BRI y .1 7 P:-.71 'u,. A P i ru i 1 1.7 ''' Mir ' --.+zy w am -' ' '' '� ., ,•, p`; .- 1 '� , i ,' ; rv' ��{CPA 2Df CPA-2BR1 fjY l aI f, ii liO�ICPA-4BRI i• 4 CPA-4DI CPA-38RI ' , CPA 3D� ,' \ < ' ,, --*"'"14: -'r----__ . , :� ' 2 , • 1 ' � � i, y " ' j 1, 044 �- . , 'rI _7l «# r. ' f i�. a -. "� E • PPER EAST CHANNEL cite .1 �� �tvl x" F. F j ` f —i° '� i r 1 • r,^ a ,. .,,,t• 14. .„,,, .i.„,,,,,,..,. . ,,,,,,/,..4, ' 27-' ....' :or...7, .. �n'••i_.. yy,,+� ' �. `�.f�.40..k,y!lLg,±�y ,111P ` VIAL,W:_ ,,r / •'' 7e„) f4, r it,!•��Fp�9 II,t �/ /// T ` r,`s: • lKf' of ,.� - Y, s 4. R (! tii f :1 / ' F � $ ! 4.Fvia .. r / ab, 4 - ' - t' y '''e:'..'f'1'1 ' . /I�\\ , V ey 1`& t1„ ,' \ v•' s 1 , SOURCE: - - - __ -- -- - ... 1 .+® /g•aAr ,g ,, , MARCH 6,2019 AERIAL PHOTOGRAPH OBTAINED FROM NC ONE MAP GEOSPATIAL PORTAL AT 4 http://data.nconemap.corn/Reoporta l/catalop/raster/download.page 6� GRAPHIC SCALE DUKE 200 0 200 400 ENERGY IN FEET FIGURE 3-4 PROGRESS DRAWN BY:J.CHASTAIN DATE:1/17/2020 COAL PILE AREA CHECKED H ISEDECKE BY:- DATE:- CHECKEDBY:C.CRANFORD DATE:1/17/2020 ASHEVILLE ELECTRIC PLANT PROJECT N:G.RRTNFORD DATE:1/17/2020 ARDEN, NORTH CAROLINA PROJECT MANAGER:T.PLATTING synTerra www.synterracorp.com r E-01 70 - — 800 60 --- — = 'LT700 ,. CO 600 50 m 500 0 c40 0 a) _ c _ 400 v --411-Nickel u 30 - I c o -•-Copper c — 300 U v '` 20 0 - Boron ,^ - L c 200 pip o _ U - 10 - - 100 t - 11111 0 t._-..+___r...--+.—r----r r , — ♦ I t I 1--- 0 �1 6 JO/�S<-)0 /J�<30 GJ<)01. %JO/v-0 -'eOJ`9 J%OJS 9/-SOLO S F-01 80 - I ! - 800 - 70 - 700 J - 00 - 60 _ 600 .tsoli 50 + 500 0 a) - L 0 40 400 v - Nickel U .. u ac, 30 - 300 o -4-Copper uo o Boron v 20 r 200 co It 10 1 100 0 'PO 6� 6�% r �� ja 9���S J8 J O� 9 i� 1v/�O /O O � /O7 i) b JS J6 JT 9 LEGEND DRAWN BY:T.PLATING DATE 1/2020 ug/L-micrograms per liter `f�'►j DUKE REVISED BY: K.SHECK FIGURE 3-5 t ENERGY CHECKED BY: E-01 AND F-01 TIME SERIES PLOTS— APPROVED BY: BORON, COPPER, AND NICKEL PROJECT MANAGER:G.BARRIER SOC WQ S17-010 RE-ASSESSMENT , ASHEVILLE PLANT synTerra www.synterracorp.com ARDEN, NORTH CAROLINA