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Home My WebLink AboutNC0005088_04_CSS_CAP Update 2019_Tables_20191231Corrective Action Plan Update December 2019 Cliffside Steam Station TABLES (CAP Content Section 9) SynTerra Corrective Action Plan Update December 2019 Cliffside Steam Station SynTerra Table ES-1 Summary of CSS Assessment Documentation Included in Executive Summary text Corrective Action Plan Update December 2019 Cliffside Steam Station SynTerra Table ES-2 Summary of CSS Assessment Activities Included in Executive Summary text Corrective Action Plan Update December 2019 Cliffside Steam Station SynTerra Table ES-3 Components of Source Control, Active Remediation, and Monitoring Included in Executive Summary text TABLE 1-1 SUMMARY OF ONSITE INCIDENTS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Station Station DEQ Incident Occurrence Closure Release Proximity to Name Location Section Number Date Status Date Type Latitude Longitude Basins (ft) Notes Cliffside Mooresboro UST 3693 7/15/1988 Closed 6/23/1997 Petroleum 35.220833 -81.7575 400 Cliffside Mooresboro UST 28482 10/9/2006 Closed 2/5/2007 Petroleum 35.218611 -81.759722 496 Incident Name: Duke Dozer Diesel Cliffside Mooresboro UST 28594 12/17/2007 Closed 3/7/2008 Petroleum 35.208056 -81.770556 1,251 Incident Name: Duke Energy Parcel 6 Incident Name: Duke Energy Cliffside Mooresboro UST 28595 12/13/2007 Closed 3/7/2008 Petroleum 35.207778 -81.765556 548 Parcel 33 Incident Name: Duke Energy Cliffside Mooresboro UST 28596 12/21/2007 Closed 3/7/2008 Petroleum 35.208889 -81.77 1,019 Parcel 34 Cliffside Mooresboro UST 41322 11/5/2014 Open NA Petroleum 35.22 -81.76 560 Incident Name: #5 Fuel Oil Release Notes: Onsite incident records provided by Duke Energy DEQ - Department of Environmental Quality ft - feet UST - Underground Storage Tank NA - Not Available Prepared By: TJG Checked By: SAS Page 1 of 1 TABLE 3-1 SUMMARY OF ONSITE FACILITIES CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Evaluated Facility as Source CSA Operational Source Area or Name ArreAaP n Schedule Status Material Capacity Rationale for Evaluation Update Coal Active Ash Ash/NPDES Basin Yes NA Inactive Permitted 86 acres CAMA regulated unit waste streams Ash Adjacent to and within Storage Yes NA Inactive Coal Ash 7 acres same groundwater flow Area regime as AAB Unit 5 Inactive Yes NA Inactive Coal Ash 46 acres CAMA regulated unit Ash Basin Former Units 1-4 Yes NA Closed Coal Ash 14 acres CAMA regulated unit Ash Basin In separate groundwater flow regime from ash basins; select monitoring data included in CAP figures and modeling since certain CAMA wells monitor nearby Unit 6 groundwater. This area has Source No March Not Unknown Unknown been determined to be a Area 2020 Applicable separate source area from the AAB (groundwater is not underflowing Suck Creek at this location contributing to groundwater standard exceedances). Area will be assessed on a separate timeline. Coal Ash and Phase 1 - Not hydrologically CCP No NA Operational operational 23.3 acres connected to the ash basins Landfill waste Phase 2 - and with NCDEQ DWM 16.9 acres regulatory oversight Coal Pile No March Operational Coal 22 acres Upgradient of U1-4 AB 2020 Gypsum March Stack -out No 2020 Operational Gypsum 1 acre Upgradient of U1-4 AB Area Unit 5 March Not Not hydrologically Switchyard No 2020 Applicable Coal Ash Unknown connected to the ash basins (north of Broad River) Prepared by: SAS Checked by: TJG Notes CSA Schedule - applicable only for units identified in the letter "Final Comprehensive Site Assessment and Corrective Action Plans Approvals for Duke Energy Coal Ash Facilities" (April 5, 2019) CAMA - North Carolina Coal Ash Management Act of 2014 CAP - Corrective Action Plan DWM - Division of Waste Management NA - not applicable NCDEQ - North Carolina Department of Environmental Quality Page 1 of 1 TABLE 4-1 BACKGROUND SOIL SAMPLE SUMMARY CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Soil Boring Depth Range (ft bgs) Number of Sampled Intervals 13G-1D (3.5-10) 2 BG-2D (3.5-30) 4 MW-30D (3.5-30) 4 MW-32D (3.5-20) 3 M W-32S (22.5-24) 1 MW-42D (28.5-30) 1 GWA-25D (8.5-10) 1 BGSB-BG-01 (6-20) 3 BGSB-BG-02 (2-7) 2 BGSB-GWA-25 (6-15) 2 BGSB-MW-30 (6-25) 3 BGSB-MW-32 (2-15) 2 Note: ft bgs - feet below ground surface Prepared by: TJG Checked by: SAS Page 1 of 1 TABLE 4-2 BACKGROUND VALUES FOR SOIL CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Reporting Unit PSRG Protection of Groundwater 2018 Background Threshold Value' 2019 Updated Background 2 Threshold Value Piedmont Background Threshold Value Range pH* S.U. NE 4.0-6.8 4.0-6.8 2.3-9.8 Aluminum mg/kg 110,000 61,758 81,619 25,978 - 61,758 Antimony mg/kg 0.9 0.64 0.64 0.177 - 0.9 Arsenic mg/kg 5.8 7.8 10.26 1.2 - 43.13 Barium mg/kg 580 198.2 304 122.2 - 1,063 Beryllium mg/kg 63 1.8 1.769 1.2 - 4.52 Boron mg/kg 45 31 30 14.4 - 56.3 Cadmium mg/kg 3 0.03 0.49 0.03 -1 Calcium mg/kg NE 282 1,300 282 - 8,769 Chloride mg/kg NE 17 400 12 - 423 Chromium mg/kg 3.8 142.4 142 20 - 440 Cobalt mg/kg 0.9 48 47.53 27 - 81.68 Copper mg/kg 700 40 40 17.4 - 216 Iron mg/kg 150 74,362 74,362 24,500 - 85,345 Lead mg/kg 270 44 44.37 7.5 - 95.23 Magnesium mg/kg NE 8,225 17,119 760 - 51,829 Manganese mg/kg 65 672 1,078 370 - 3,388 Mercury mg/kg 1 0.1 0.10 0.04 - 0.113 Molybdenum mg/kg 7.1 7.7 4.1 1.83 - 12 Nickel mg/kg 130 72 72 9.2 - 237 Nitrate (as N) mg/kg NE 0.26 0.26 0.25 - 31.2 Nitrate mg/kg NE --- 49 40.3 - 43.7 Potassium mg/kg NE 13,697 13,697 427 - 35,600 Selenium mg/kg 2.1 3.8 6.857 1.58 - 5.348 Sodium mg/kg NE 198 1,200 198 - 1,500 Strontium mg/kg 1,500 9.9 9.9 7.1 - 200 Sulfate mg/kg 1,438^ 13 400 12 - 437 Thallium mg/kg 0.28 1.1 1 0.166 - 2.132 Total Organic Carbon mg/kg NE --- 4,960 742 - 4,070 Vanadium mg/kg 350 161 163.3 42 - 230.9 Zinc mg/kg 1 1,200 1 140 1 160 1 60.5 - 325.5 Prepared by: T]G Checked by: V3H Notes: 2018 Background threshold values were approved by North Carolina Department of Environmental Quality (NCDEQ) on May 14, 2018. ^ - PSRG Protection of Groundwater value was calculated using the equation shown in Section 6 * - Upper and lower threshold values calculated for parameter ' - Background threshold values were calculated using data from background unsaturated soil samples collected February 2015 to May 2015. 2 - Updated background threshold values were calculated using data from background unsaturated soil samples collected February 2015 to August 2017. The background threshold value updates retained extreme outlier concentrations in background unsaturated soil datasets (SynTerra, 2019). 3 - Piedmont background threshold value ranges include the Duke Energy calculated 20174 and 20195 background threshold values from 10 Duke Energy facilities located in the Piedmont physiographic region (Allen Steam Station 5, Belews Creek Steam Stations, Buck Steam Station, Cape Fear Steam Electric Plant4, Cliffside Steam Stations, Dan River Steam Station4, Marshall Steam Stations, Mayo Steam Electric Plants, Riverbend Steam Station 4, and Roxboro Steam Electric Plants). --- - 2018 background threshold value was not calculated for constituent. mg/kg - milligrams per kilogram NE - not established S.U. - standard unit PSRG - preliminary soil remediation goals Page 1 of 1 TABLE 4-3 BACKGROUND VALUES FOR GROUNDWATER CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Reporting Unit 15A NCAC 02L Standard 2017 Background Threshold Values' 2019 Updated Background Threshold ValueS2 Piedmont Background Threshold Values Range Shallow Flow Zone Deep Flow Zone Bedrock Flow Zone Shallow Flow Zone Deep Flow Zone Bedrock Flow Zone pH S.U. 6.5 - 8.5 4.4 - 6.1 4.8 - 6.1 5.4 - 7.4 4.0 - 6.0 4.9 - 7.2 4.5 - 7.5 3.6-9 Alkalinity mg-CaCO3/L NE 14 20 53 19 54 56 19-379 Aluminum pg/L NE 253 290 208 820 483 309 100-1,238 Antimony pg/L 1* 1 1 1 0.5 0.5 1 0.5-2.9 Arsenic pg/L 10 1 1 1 0.2 2 1 0.2 - 6.35 Barium pg/L 700 23 19 94 44 19 10.52-840 Beryllium pg/L 4* 0.2 0.2 1 0.2 0.2 0.2 0.0625-1 Bicarbonate m9-CaCO3/L NE 14 1 18 69 19 58 59 19-388 Boron pg/L 700 50 50 50 50 50 50 50 - 176.8 Cadmium pg/L 2 1 1 1 0.09 1 1 0.08 - 1 Calcium mg/L NE 3 11 16 4 1 13 17 4 - 111 Carbonate mg-CaCO3/L NE 5 5 5 5 5 5 5-10 Chloride mg/L 250 8 5 9 8 8 8 3.34 - 250 Chromium pg/L 10 4 2 4 26 2 3 43,491 Chromium (VI) pg/L NE 0.5 0.2 0.1 4 0.6 0.7 0.03 - 12 Cobalt pg/L 1* 11 5 1 21 5 2 0.088 - 88.85 Copper pg/L 1,000 7 10 5 9 8 5 0.5 - 17.15 Fluoride mg/L 2 --- --- --- 0.1 0.1 0.1 0.1 - 1.8 Iron pg/L 300 684 515 6,220 1,700 1,840 7,680 56.3 - 37,500 Lead pg/L 15 1 1 1 1 0.3 1 1 0-2 Lithium pg/L NE --- --- --- 3 12 it 2 - 95.39 Magnesium mg/L NE 2 2 2 2 2 2 1 -45 Manganese pg/L 50 169 78 89 969 260 113 2,655,496 Mercury pg/L 1 0.2 0.2 0.2 0.2 0.2 0.2 0.05 - 0.5 Methane pg/L NE 10 3 10 10 10 10 1 1 -2,505 Molybdenum pg/L NE 1 1 2 0.6 4 2 0.5-26.2 Nickel pg/L 100 1 6 13 5 12 13 7 0.87 - 48 Nitrate + Nitrite mg-N/L NE 9 3 1 4 3 1 0.02 - 6.3 Potassium mg/L NE 5 5 5 1 5 6 5 1.609-18.8 Selenium pg/L 20 1 1 1 0.5 1 1 0.5-2.4 Sodium mg/L NE 6 4 7 6 9 8 6- 190 Strontium pg/L NE 37 56 107 34 69 93 1 27 - 2,120 Sulfate mg/L 250 1 1 10 15 4 1 15 17 1.2 - 510 Sulfide mg/L NE 0.1 O.1 0.1 0.1 0.1 0.1 0.1 - 2 TDS mg/L 500 75 71 120 57 107 120 50 - 1,200 Thallium pg/L 0.2* 0.1 0.1 0.2 0.2 0.2 0.2 0.1-0.2 TOC mg/L NE 1 1 1 1 2 1 1 1- 12.3 Total Radium pCi/L NE 3 1 2 3 2 2 3 0.494-35 Total Uranium ug/mL NE 0.0005 0.0005 0.0005 1 0.0005 0.0005 0.0005 0.0002-0.864 Vanadium pg/L 0* 1 1 0.4 1 11 1 0.33-25.8 Zinc pg/L 1,0.300 15 15 1 10 1 26 14 15 5 - 140 Prepared by: HES Checked by: JHG Notes: 2017 background threshold values (BTVs) approved by North Carolina Department of Environmental Quality (NCDEQ) on September 1, 2017. Background threshold values (BTVs) have been rounded to similar levels of precision as 15A North Carolina Administrative Code (NCAC) 02L Standard or Interim Maximum Allowable Concentration (IMAC). --- - BTV was not calculated for constituent. * - IMAC of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. - BTVs were calculated using data from background groundwater samples collected ]une 2015 to September 2017 - Updated BTVs were calculated using data from background groundwater samples collected February 2010 to December 2018 - Piedmont background threshold value ranges include the Duke Energy calculated 2017' and 20192 background threshold values from 10 Duke Energy facilities located in the Piedmont physiographic region (Allen Steam Station 2, Belews Creek Steam Station, Buck Steam Station', Cape Fear Steam Electric Plant', Cliffside Steam Station, Dan River Steam Station', Marshall Steam Station, Mayo Steam Electric Plant, Riverbend Steam Station', and Roxboro Steam Electric Plant). pg/L - micrograms per liter pg/mL - micrograms per milliliter mg/L - milligrams per liter mg-CaCO3/L - milligrams calcium carbonate per liter mg-N/L - milligrams nitrogen per liter NE - not established pCi/L - picocuries per liter S.U. - standard units TDS - total dissolved solids TOC - total organic carbon Page 1 of 1 TABLE 4-4 BACKGROUND DATASET RANGES FOR SURFACE WATER CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Reporting Unit Comparison Criteria Background Range Constituents with 15A NCAC 02B (Class Water Supply: WS-IV) Standards pH S.U. 6.0-9.0 6.0 - 8.7 Dissolved Oxygen mg/L >_ 4 4.3 - 12.4 Temperature deg C <_ 32 5.5 -30.0 Turbidity NTU <_ 50 2.5 - 114.0 Arsenic pg/L 10 0.0002 j - <10 Arsenic (Dissolved) pg/L acute: 340, chronic: 150 0.077 j - <1 Barium pg/L 1000 <5 - 39 Beryllium (Dissolved) pg/L acute: 65, chronic: 6.5 <0.01 - <0.2 Cadmium (Dissolved)' pg/L acute: 0.82, chronic: 0.15 <0.05 - <1 Chloride mg/L 250 0.0043 j - 20.4 Chromium (III) (Dissolved)1,2 pg/L acute: 180, chronic: 24 NA Chromium (VI) (Dissolved) pg/L acute: 16, chronic: 11 NA Copper (Dissolved)' pg/L acute: 3.6, chronic: 2.7 <0.11 - 8.2 Fluoride mg/L 1.8 0.000064 j - <0.5 Lead (Dissolved)' pg/L acute: 14, chronic: 0.54 0.044 j - <1 Mercury pg/L chronic: 0.012 0.000532 B - <0.2 Nickel pg/L 25 0.2 j - <10 Nickel (Dissolved)' pg/L acute:140, chronic: 16 0.16 j - 2.7 Nitrate + Nitrite mg-N/L 10 <0.02 - 1 Selenium pg/L chronic: 5 0.133 j - <10 Silver (Dissolved)' pg/L acute: 0.3, chronic: 0.06 <0.07 - <1 Sulfate mg/L 250 0.62 j - 75 Thallium pg/L 2 <0.015 - <10 Total Dissolved Solids mg/L 500 <25 - 10,000 Total Hardness mg/L 100 10.7 - 18.8 Zinc (Dissolved)' I pg/L I acute: 36, chronic: 36 1 <2.5 - 18 j+ Constituents with USEPA National Recommended Water Quality Criteria Alkalinity mg/L chronic: 20 5.2 - 64.2 Aluminum pg/L acute: 620, chronic: 300 69.2 j - 1,760 M1 Antimony pg/L 5.6 <0.1 - <5 Iron pg/L 1000 225 - 3,630 Manganese I pg/L 1 50 1 17.8 - 160 Constituents without 02B or USEPA Criteria Bicarbonate mg-CaC0A NE 8.3 - 64.2 Boron pg/L NE 3.39 j - <50 Cadmium pg/L NE 0.035 j - <1 Calcium mg/L NE 2.12 - 44.3 Carbonate Alkalinity mg-CaC0A NE <1 - 11 Chromium pg/L NE 0.0008 j - <10 Chromium (VI) pg/L NE 0.021 j - <0.6 Cobalt pg/L NE 0.0013 j - 2.1 Copper pg/L NE <0.11 - 2.71 j Lead pg/L NE 0.083 j - <10 Lithium pg/L NE 0.45 j - 0.61 Magnesium I m /L I NE 1 1.06 - 5.67 Page 1 of 2 TABLE 4-4 BACKGROUND DATASET RANGES FOR SURFACE WATER CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Reporting Unit Comparison Criteria Background Range Constituents without 02B or USEPA Criteria (Continued) Methane pg/L NE 2.2 j - 344 Molybdenum pg/L NE <0.11 - 1.7 Potassium mg/L NE 1.56 - 11.2 Sodium mg/L NE 1.57 - 10 Strontium pg/L NE 16.3 - 59.3 Sulfide mg/L NE <0.1 Total Organic Carbon mg/L NE 0.51 j - 7.7 Total Radium pCi/L NE NA Total Uranium pg/mL NE NA Vanadium pg/L NE <0.3 - 5.5 Zinc L I NE 1.71 ' - 47.2 B Prepared by: LWD Checked by: GRK Notes• Background locations were approved by North Carolina Department of Environmental Quality (NCDEQ). All samples are subject to Class C water quality standards. 1 Standard value dependent on hardness. Calculated hardness dependent metal standards represent most conservative value. Standards are calculated using 25 mg/L hardness, regardless if actual instream hardness values are greater than 25 mg/L. z Chromium speciation is not performed for trivalent chromium (Cr(III)). Trivalent values are derived by subtracting hexavalent chromium values from dissolved chromium values. Where a dissolved chromium value is less than the detection limit ("<"), it is considered a whole number for purposes of deriving a trivalent chromium value. acute - "Compliance with acute instream metals standards shall only be evaluated using an average of two or more samples collected within one hour." Reference 15A NCAC 02B .0211 chronic - "Compliance with chronic instream metals standards shall only be evaluated using averages of a minimum of four samples taken on consecutive days, or as a 96-hour average" Reference 15A NCAC 02B .0211. < - concentration not detected at or above the adjusted reporting limit. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 1OX the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j+ - Estimated concentration, biased high. M1 - Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable. Deg C - Degrees Celsius mg/L - milligrams per liter pg/L - micrograms per liter Ng/mL - micrograms per milliliter mg-CaCO3/L - milligrams calcium carbonate per liter mg-N/L - milligram nitrogen per liter NA - not available NE - not established NTU - Nephelometric Turbidity Unit pCi/L - picocuries per liter S.U. - standard unit Page 2 of 2 TABLE 4-5 BACKGROUND DATASET RANGES FOR SEDIMENT CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Reporting Unit Background Range pH S.U. 6.2 - 6.7 Aluminum mg/kg 12,000 - 18,000 Antimony mg/kg <0.68 - <0.9 Arsenic mg/kg 1.4 - 1.5 Barium mg/kg 47 - 110 Beryllium mg/kg 0.48 - 1.1 Boron mg/kg <3.7 - <4.3 Cadmium mg/kg 0.052 j - 0.25 Calcium mg/kg 590 - 1,100 Chloride mg/kg 9.8 j - <19 Chromium mg/kg 16 - 26 Chromium (III) mg/kg NA Cobalt mg/kg 3.6 - 10 Copper mg/kg 5.2 - 13 Iron mg/kg 8,300 - 18,000 Lead mg/kg 7.4 - 12 Magnesium mg/kg 1,700 - 3,400 Manganese mg/kg 41 - 350 Mercury mg/kg <0.13 - <0.16 Molybdenum mg/kg <3 - <3.4 Nickel mg/kg 5.9 - 10 Nitrate (as N) mg/kg <0.35 - <0.41 M Nitrate mg/kg NA Potassium mg/kg 1,400 - 2,800 Selenium mg/kg <1.8 - <2.3 Silver mg/kg <0.74 - <0.86 Sodium mg/kg <370 - <430 Strontium mg/kg 3.5 - 6.9 Sulfate mg/kg <18 - <20 Sulfide mg/kg <39.8 - <42.9 Thallium mg/kg 0.22 j - 0.33 Total Organic Carbon mg/kg 10,300 - 26,900 Vanadium mg/kg 28 - 51 Zinc mg/kg 23 - 48 Notes• Background locations were approved by North Carolina Department of Environmental Quality (NCDEQ). < - concentration not detected at or above the adjusted reporting limit. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. mg/kg - milligrams per kilogram M - Matrix spike / matrix spike dup failure. NA - not available S.U. - standard unit Prepared by: LWD Checked by: GRK Page 1 of 1 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Elevation (ft. NAVD 88) April 2019Screen Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Flow AB-1BROR 773.58 647.39 597.89 61.10 712.48 - - Bedrock AB-11) 773.44 652.30 647.23 61.60 711.84 121.5 126.5 Deep AB-1S 773.19 719.80 704.80 39.65 733.54 54.0 69.0 Shallow AB-2BRO 773.47 694.53 624.53 30.66 742.81 - - Bedrock AB-21D 773.00 700.97 695.97 38.13 734.87 72.5 77.5 Deep AB-2S 772.92 729.53 724.53 30.62 742.30 44.0 49.0 Shallow AB-3-LA15 796.86 726.08 721.08 - - 67.5 72.5 Ash Pore Water AB-3-MA15 796.78 737.52 732.52 35.31 761.47 56.2 61.2 Ash Pore Water AB-3BR 796.55 617.91 607.91 36.86 759.69 175.5 185.5 Bedrock AB-3BRA 796.18 -- 646.35 74.86 721.32 - 147.5 Bedrock AB-3BRUA 796.02 668.26 663.26 83.92 712.10 125.0 130.0 Deep AB-3I 795.97 701.62 691.62 34.32 761.65 92.0 102.0 Shallow AB-3S 795.64 771.66 756.66 Below Pump - 22.0 37.0 Ash Pore Water AB-3SL 796.02 732.36 722.36 34.49 761.53 62.2 72.2 Ash Pore Water AB-3SLA 796.90 733.75 723.75 - - 60.0 70.0 Ash Pore Water AB-41-A15 771.10 735.68 730.68 10.53 760.57 32.4 37.4 Ash Pore Water AB-4UA15 771.62 753.32 748.32 11.38 760.24 14.9 19.9 Ash Pore Water AB-4BR 770.66 664.06 659.06 14.48 756.18 104.5 109.5 Bedrock AB-41D 770.59 713.54 708.54 9.67 760.92 55.0 60.0 Deep AB-4S 770.59 763.51 748.51 10.14 760.45 5.0 20.0 Ash Pore Water AB-4SL 770.61 739.71 729.71 9.98 760.63 28.7 38.7 Ash Pore Water AB-5BR 772.13 677.90 673.00 9.45 762.68 91.2 96.1 Bedrock AB-5BRU 771.81 709.31 704.31 7.32 764.49 60.5 65.5 Deep AB-5S 771.74 763.88 748.88 8.10 763.64 5.0 20.0 Ash Pore Water AB-6BR 770.61 672.76 667.76 10.61 760.00 96.0 101.0 Bedrock AB-61) 770.68 702.89 697.89 5.59 765.09 65.8 70.8 Deep AB-6S 770.56 763.38 748.38 6.20 764.36 5.0 20.0 Ash Pore Water AB-7BR 795.19 607.18 597.18 35.46 759.73 185.5 195.5 Bedrock AB-7BRU 795.90 646.15 636.15 48.00 747.90 147.0 157.0 Deep AB-7S 795.80 746.15 736.15 34.84 760.96 47.0 57.0 Ash Pore Water AB-8BR 774.93 655.11 650.11 13.41 761.52 117.0 122.0 Bedrock AB-8BRU 775.13 685.18 675.18 13.68 761.45 87.0 97.0 Deep AB-8I 774.99 715.21 705.21 13.31 761.68 57.0 67.0 Shallow AB-8S 774.91 759.69 749.69 13.01 761.90 12.5 22.5 Ash Pore Water AB-9BR 771.15 659.30 649.30 11.50 759.65 109.0 119.0 Bedrock AB-9 D 771.04 710.71 700.71 10.87 760.17 57.5 67.5 Deep AB-9S 770.81 754.12 744.12 10.52 760.29 14.0 24.0 Ash Pore Water AS-11) 809.41 701.52 696.52 77.20 732.21 106.0 111.0 Deep AS-1SB 809.20 723.83 708.83 75.81 733.39 83.0 98.0 Shallow AS-2BR 698.74 604.44 599.44 38.61 660.13 92.0 97.0 Bedrock AS-21D 697.26 640.43 635.43 28.92 668.34 55.0 60.0 Deep AS-2S 697.84 680.23 665.23 22.45 675.39 15.5 30.5 Shallow AS-3BRU 754.16 704.11 699.11 49.08 705.08 48.5 53.5 Deep AS-41) 837.71 740.59 735.59 90.29 747.42 95.0 100.0 1 Deep AS-4S 837.49 751.30 741.30 91.72 745.77 84.4 94.4 Shallow AS-5BR 739.77 664.80 659.80 34.16 705.61 75.1 80.1 Bedrock AS-5BRU 740.45 685.59 680.59 37.68 702.77 55.0 60.0 Deep AS-5S 739.72 710.70 695.70 34.82 704.90 29.3 44.3 Shallow AS-6BRA 822.29 665.36 660.36 97.25 725.04 153.5 158.5 Bedrock AS-61) 818.30 694.17 689.17 93.56 724.74 123.0 128.0 Deep AS-6S 817.74 729.13 714.13 92.70 725.04 86.0 101.0 Shallow AS-7BR 742.70 618.29 613.29 35.15 707.55 122.0 127.0 Bedrock AS-7BRA 737.25 614.37 604.37 46.55 690.70 120.0 130.0 Bedrock AS-7BRB 746.11 632.21 622.21 52.83 693.28 111.0 121.0 Bedrock AS-7BRL 733.79 -- -- 32.77 701.02 - - Bedrock AS-71) 742.90 658.27 653.27 34.06 708.84 82.5 87.5 Deep AS-7I 735.66 675.89 670.89 30.43 705.23 57.0 62.0 Shallow AS-7S 742.06 711.33 696.33 27.56 714.50 28.5 43.5 1 Ash Pore Water AS-8BR 725.18 635.51 625.51 94.86 630.32 90.0 100.0 Bedrock AS-81) 724.95 662.14 657.14 31.12 693.83 62.9 67.9 Deep AS-8S 724.79 702.09 1 687.09 20.14 704.65 23.0 38.0 Shallow AS-9BR 727.49 648.76 638.76 1 68.90 658.59 79.4 89.4 Bedrock AS-9 D 727.07 693.77 683.77 22.75 704.32 34.0 44.0 Dee Page 1 of 6 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Elevation (ft. NAVD 88) April 2019Screen Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Frin low BG-1BRA 806.00 709.84 704.84 24.16 781.84 93.0 98.0 Bedrock BG-11D 802.63 734.40 729.40 21.02 781.61 66.5 71.5 Deep BG-IS 802.67 780.71 765.71 20.74 781.93 20.0 35.0 Shallow BG-21D 846.51 795.65 790.65 42.56 803.95 49.0 54.0 Deep CCPMW-ID 875.89 824.19 819.19 30.56 845.33 49.0 54.0 Bedrock CCPMW-15 875.58 843.34 833.34 30.01 845.57 30.0 40.0 Shallow CCPMW-2D 842.38 774.91 769.91 35.33 807.05 65.0 70.0 Deep CCPMW-2S 842.24 808.17 798.17 34.29 807.95 32.0 42.0 Shallow CCPMW-3D 811.74 786.74 781.74 11.01 800.73 26.0 31.0 Deep CCPMW-3S 811.56 801.54 796.54 9.65 1 801.91 9.0 14.0 Shallow CCPMW-4 845.95 792.62 777.62 22.14 823.81 50.0 65.0 Bedrock CCPMW-5 858.63 793.23 783.23 38.40 820.23 62.5 72.5 Bedrock CCPMW-6D 854.35 801.27 791.27 31.86 822.49 50.0 60.0 Bedrock CCPMW-6S 854.38 817.65 807.65 31.88 822.50 33.5 43.5 Shallow CCPTW-ID 838.53 775.30 770.30 23.72 814.81 61.0 66.0 Deep CCPTW-1S 838.92 812.14 802.14 22.21 816.71 25.0 35.0 Shallow CCPTW-2 842.18 804.55 794.55 38.05 804.13 35.0 45.0 Shallow CCR-7S 790.54 753.30 738.30 38.90 751.64 34.5 49.5 Shallow CCR-71) 790.40 701.22 696.22 37.33 753.07 86.0 91.0 Deep CCR-11D 736.83 709.40 704.40 5.62 731.21 24.5 29.5 Deep CCR-11S 737.07 729.27 714.27 6.56 730.51 4.5 20.0 Shallow CCR-12S 770.82 734.57 719.57 31.90 738.92 33.0 48.0 Shallow CCR-12D 770.10 707.61 702.61 31.25 738.85 59.0 64.0 Deep CCR-12BR 770.85 668.00 663.00 34.64 736.21 100.0 105.0 Bedrock CCR-13D 787.75 757.37 752.37 25.21 762.54 27.0 32.0 Deep CCR-14D 805.14 754.70 749.70 45.83 759.31 47.0 52.0 Deep CCR-15D 780.40 763.56 758.56 15.69 764.71 15.0 20.0 Deep CCR-16D 780.13 716.90 711.90 13.82 766.31 63.0 68.0 Deep CCR-16S 780.00 762.48 747.48 13.48 766.52 18.0 33.0 Shallow CCR-17BR 789.52 716.88 711.88 42.72 746.80 75.2 77.0 Bedrock CCR-3BR 763.00 620.69 615.69 39.19 723.81 51.5 56.5 Bedrock CCR-41D 781.43 761.12 756.12 23.98 757.45 17.5 22.5 Deep CCR-51) 784.10 753.75 748.75 25.14 758.96 29.5 34.5 Deep CCR-61D 793.86 732.21 727.21 34.90 758.96 58.5 63.5 Deep CCR-6S 793.69 765.34 750.34 34.40 759.29 29.0 44.0 Shallow CCR-8BR 801.98 718.87 713.87 41.62 760.36 80.4 85.4 Bedrock CCR-81) 798.99 751.13 746.13 38.34 760.65 44.5 49.5 Deep CCR-91D 752.89 727.19 722.19 17.10 735.79 22.5 27.5 Deep CCR-CCP-10DA 853.09 783.12 778.12 30.06 823.03 66.7 71.7 Bedrock CCR-CCP-10S 853.67 820.17 805.17 30.58 823.09 30.2 45.2 Shallow CCR-CCP-I1BR 862.61 793.01 788.01 40.38 822.23 71.0 76.0 Bedrock CCR-CCP-12D 859.70 791.42 786.42 38.33 821.37 68.0 73.0 Deep CCR-CCP-12S 859.59 822.57 807.57 37.45 822.14 37.0 52.0 Shallow CCR-CCP-13D 857.00 820.53 815.53 30.45 826.55 33.0 38.0 Deep CCR-CCP-14D 859.86 816.18 811.18 36.74 823.12 39.0 44.0 Deep CCR-CCP-15D 880.12 815.00 810.00 47.22 832.90 66.1 71.1 Bedrock CCR-CCP-15S 880.10 838.41 828.41 44.60 835.50 44.0 54.0 Shallow CCR-CCP-16BR 814.21 699.35 689.35 34.38 779.83 112.1 122.1 Bedrock CCR-CCP-16S 913.90 771.16 761.16 28.19 885.71 40.0 50.0 Shallow CCR-CCP-1D 878.84 820.59 815.59 45.79 833.05 55.0 60.0 Bedrock CCR-CCP-2D 870.51 815.20 810.20 44.11 826.40 51.0 56.0 Deep CCR-CCP-3DA 858.41 791.03 786.03 49.71 808.70 64.6 69.6 Bedrock CCR-CCP-3S 862.17 810.01 795.01 50.24 811.93 50.0 65.0 Shallow CCR-CCP-4D 855.36 798.88 793.88 47.58 807.78 53.0 58.0 Deep CCR-CCP-5D 847.09 773.51 768.51 41.64 805.45 70.0 75.0 Deep CCR-CCP-5S 847.46 794.88 779.88 42.40 805.06 49.0 64.0 Shallow CCR-CCP-6D 834.50 744.09 739.09 24.31 810.19 90.0 95.0 Deep CCR-CCP-6S 834.19 788.68 773.68 18.90 815.29 45.0 60.0 Shallow CCR-CCP-7D 841.56 818.53 808.53 22.81 818.75 23.0 33.0 Deep CCR-CCP-8D 845.48 829.08 819.08 24.20 821.28 17.0 27.0 Deep CCR-CCP-9D 842.30 777.37 772.37 21.78 820.52 61.8 66.8 Bedrock CCR-CCP-9S 841.97 805.88 790.88 23.02 818.95 30.3 45.3 Shallow CCR-IB-1S 668.91 663.22 653.22 7.81 661.10 6.0 16.0 Shallow CCR-IB-1D 668.76 648.62 643.62 7.37 661.39 20.0 25.0 Dee Page 2 of 6 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Elevation (ft. NAVD 88) April 2019Screen Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Frin low CCR-IB-3S 678.74 666.63 651.63 16.68 662.06 12.0 27.0 Shallow CCR-IB-3D 678.92 640.67 635.67 17.85 661.07 38.0 43.0 Deep CCR-U5-3S 695.90 686.91 676.91 6.21 689.69 7.0 17.0 Shallow CCR-U5-3D 694.88 670.63 665.63 10.54 684.34 22.0 27.0 Deep CCR-IB-3BR 682.56 609.34 604.34 20.91 661.65 69.9 74.9 Bedrock CCR-U5-10D 785.63 745.25 740.25 22.54 763.09 36.0 41.0 Deep CCR-U5_10S 784.93 763.83 753.83 21.79 763.14 18.0 28.0 Shallow CCR-U5-ID 782.01 737.58 732.58 36.68 745.33 41.0 46.0 Deep CCR-1.15-213 775.22 710.40 705.40 63.37 711.85 60.5 65.5 Deep CCR-U5-4BR 696.27 616.98 611.98 8.48 1 687.79 79.8 84.8 1 Bedrock CCR-1.15-413 699.62 664.07 659.07 18.17 681.45 31.0 36.0 Deep CCR-U5-4S 698.27 684.92 669.92 16.85 681.42 10.0 25.0 Shallow CCR-1.15-513 768.89 698.49 693.49 57.76 711.13 66.0 71.0 Deep CCR-U5-6DA 719.04 697.59 692.59 8.97 710.07 21.5 26.5 Deep CCR-U5-6S 717.69 708.29 698.29 7.80 709.89 6.0 16.0 Shallow CCR-U5-8D 759.63 700.73 695.73 6.00 753.63 58.5 62.5 Deep CCR-U5-8S 760.48 745.96 730.96 7.10 753.38 11.0 26.0 Shallow CCR-U5-9S 763.11 754.08 739.08 6.45 756.66 6.0 21.0 Shallow CLMW-1 789.08 738.28 728.28 36.84 752.24 47.5 57.5 Shallow CLMW-2 728.92 683.84 673.84 36.85 692.07 43.0 53.0 Shallow CLMW-3D 774.92 679.47 669.47 44.70 730.22 93.0 103.0 Deep CLMW-3S 775.07 723.62 713.62 44.80 730.27 49.0 59.0 Shallow CLMW-5D 775.39 681.39 671.39 - - 94.0 104.0 Deep CLMW-5S 773.78 723.97 713.97 35.88 737.90 50.0 60.0 Shallow CLMW-6 770.86 747.77 737.77 3.50 767.36 20.0 30.0 Shallow CLP-1 730.78 700.90 690.90 24.00 706.78 25.0 35.0 Shallow CLP-2 672.66 662.39 652.39 15.38 657.28 8.0 18.0 Shallow CLP-3 789.33 753.91 743.91 ABD - 30.0 40.0 Shallow CLP-4 794.45 758.81 718.81 36.50 757.95 33.0 73.0 Shallow GWA-10D 679.74 632.44 627.44 18.12 661.62 47.6 52.6 Deep GWA-10S 679.55 667.85 652.85 18.32 661.23 12.0 27.0 Shallow GWA-11BR 679.48 607.02 602.02 18.96 660.52 69.1 74.1 Bedrock GWA-11BRL 678.87 504.90 494.90 14.52 664.35 171.0 181.0 Bedrock GWA-11BRU 674.99 638.20 633.20 13.95 661.04 37.0 42.0 Deep GWA-11S 674.98 663.24 648.24 13.78 661.20 12.0 27.0 Shallow GWA-12BRU 719.66 669.95 664.95 35.74 683.92 48.0 53.0 Deep GWA-12S 719.40 698.59 683.59 26.64 692.76 19.0 34.0 Shallow GWA-13BR 724.12 643.88 638.88 22.26 701.86 80.5 85.5 Bedrock GWA-14BR 712.55 593.73 583.73 30.23 682.32 118.5 128.5 Bedrock GWA-14D 712.52 664.85 659.85 29.86 682.66 48.0 53.0 Deep GWA-14S 712.41 691.41 676.41 DRY - 21.3 36.3 Shallow GWA-1BRU 781.29 756.51 751.51 12.25 769.04 22.8 27.8 Deep GWA-20BR 736.61 679.26 675.26 7.09 729.52 54.0 59.0 Bedrock GWA-20D 736.24 709.31 704.31 12.21 724.03 25.0 30.0 Deep GWA-20S 736.13 729.68 714.68 8.30 727.83 4.5 19.5 Shallow GWA-21BR 672.98 609.66 604.66 0.00 672.98 60.6 65.6 Bedrock GWA-21BRL 673.22 546.50 536.50 0.00 673.22 125.0 135.0 Bedrock GWA-21BRU 672.91 650.72 645.72 10.99 661.92 20.0 25.0 Deep GWA-21S 673.32 665.87 655.87 10.50 662.82 5.5 15.5 Shallow GWA-22BRU 665.19 646.26 641.26 9.52 655.67 17.0 22.0 Deep GWA-22S 665.19 660.64 650.64 7.40 657.79 2.6 12.6 Shallow GWA-23D 786.80 761.34 756.34 27.07 759.73 23.5 28.5 Deep GWA-24BR 798.92 730.95 725.95 13.12 785.80 65.0 70.0 Bedrock GWA-24D 794.94 765.02 760.02 14.52 780.42 28.0 33.0 Deep GWA-24S 794.47 778.52 768.52 15.68 778.79 14.0 24.0 Shallow GWA-25D 792.01 753.49 748.49 21.35 770.66 36.5 41.5 Deep GWA-25S 791.81 779.64 764.64 21.18 770.63 10.0 25.0 Shallow GWA-26D 782.98 712.58 707.38 14.62 768.36 68.6 73.8 Deep GWA-26S 783.36 771.23 756.23 15.35 768.01 10.2 25.2 Shallow GWA-27BR 805.50 699.21 694.21 48.65 756.85 103.9 108.9 Bedrock GWA-27DA 805.48 751.95 746.95 49.70 755.78 51.0 56.0 Deep GWA-28BR 757.90 670.91 665.91 44.05 713.85 85.0 90.0 Bedrock GWA-28BRU 758.35 702.39 697.39 38.80 719.55 53.9 58.9 Deep GWA-28S 757.74 733.48 718.48 31.28 726.46 22.5 37.5 Shallow Page 3 of 6 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Elevation (ft. NAVD 88) April 2019Screen Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Frin low GWA-29BRA 679.76 638.04 633.04 15.68 664.08 48.4 58.4 Bedrock GWA-29D 679.56 628.54 618.54 20.63 658.93 20.5 25.5 Deep GWA-2BR 685.43 619.22 614.22 12.43 673.00 63.0 68.0 Bedrock GWA-2BRA 685.64 625.54 615.54 12.80 672.84 58.0 68.0 Bedrock GWA-2BRU 685.35 650.86 645.86 12.37 672.98 32.4 37.4 Deep GWA-2S 685.56 677.34 662.34 10.55 675.01 6.0 21.0 Shallow GWA-30BR 806.90 740.01 735.01 34.46 772.44 65.0 70.0 Bedrock GWA-30BRU 806.72 766.88 761.88 25.47 781.25 38.0 43.0 Deep GWA-30S 806.89 787.49 777.49 21.77 785.12 17.5 27.5 Shallow GWA-31BRA 757.13 637.16 627.16 45.62 1 711.51 116.5 126.5 1 Bedrock GWA-31D 754.89 742.54 737.54 16.46 738.43 10.4 15.4 Deep GWA-32BR 698.56 636.58 631.58 27.07 671.49 60.0 65.0 Bedrock GWA-32D 698.53 661.67 656.67 27.20 671.33 35.0 40.0 Deep GWA-33BR 722.94 636.10 631.10 20.83 702.11 85.0 90.0 Bedrock GWA-33D 722.88 695.11 690.11 4.18 718.70 26.0 31.0 Deep GWA-33S 722.71 715.81 705.81 3.12 719.59 5.0 15.0 Shallow GWA-34S 715.88 698.25 683.25 4.50 711.38 14.3 29.3 Shallow GWA-34BR 715.38 661.48 651.48 0.00 715.38 51.0 61.0 Bedrock GWA-35D 697.74 633.25 628.25 23.69 674.05 62.0 67.0 Deep GWA-35S 698.04 675.69 660.69 23.31 674.73 20.0 35.0 Shallow GWA-36D 710.53 624.52 619.52 6.33 704.20 83.0 88.0 Deep GWA-36S 710.53 700.80 685.80 7.40 703.13 7.0 22.0 Shallow GWA-37D 710.47 612.67 607.67 35.99 674.48 95.0 100.0 Deep GWA-37S 710.56 667.59 652.59 40.02 670.54 40.0 55.0 Shallow GWA-38D 760.01 704.28 699.28 52.99 707.02 53.0 58.0 Deep GWA-38S 760.01 721.85 706.85 53.44 706.57 35.0 50.0 Shallow GWA-39S 723.41 717.17 715.17 3.08 720.33 3.0 5.0 Shallow GWA-31D 757.53 694.08 689.08 56.51 701.02 62.0 67.0 Deep GWA-40S 723.09 716.07 713.07 6.53 716.56 4.0 7.0 Shallow GWA-42S 724.65 717.94 712.94 8.76 715.89 4.0 9.0 Shallow GWA-43D 725.10 679.85 674.85 15.64 709.46 42.5 47.5 Deep GWA-43S 725.19 716.05 701.05 7.08 718.11 6.0 21.0 Shallow GWA-44BR 769.03 671.86 666.86 30.82 738.21 94.1 99.1 Bedrock GWA-44D 769.07 696.02 691.02 39.62 729.45 70.0 75.0 Deep GWA-44S 768.88 729.71 714.71 41.45 727.43 36.0 51.0 Shallow GWA-45D 816.59 730.11 725.11 62.12 754.47 84.0 89.0 Deep GWA-45S 816.55 769.93 759.93 53.02 763.53 45.5 55.5 Shallow GWA-46D 788.60 767.55 762.55 25.01 763.59 18.0 23.0 Deep GWA-47D 805.18 752.53 747.53 43.81 761.37 50.0 55.0 Deep GWA-48BR 808.89 723.53 718.53 19.41 789.48 82.0 87.0 Bedrock GWA-41D 711.64 677.84 672.84 4.06 707.58 32.0 37.0 Deep GWA-4S 711.61 704.83 689.83 2.58 709.03 5.0 20.0 Shallow GWA-51D 792.99 734.79 729.79 52.74 740.25 55.5 60.5 Deep GWA-54D 765.03 655.31 650.31 41.51 723.52 107.0 112.0 Deep GWA-54-BRO 764.65 640.01 576.51 41.57 723.08 112.0 175.0 Bedrock GWA-54S 763.76 723.81 708.81 42.19 721.57 37.0 52.0 Shallow GWA-56D 708.70 641.99 636.99 29.78 678.92 67.0 72.0 Deep GWA-56S 708.58 683.82 668.82 27.05 681.53 25.0 40.0 Shallow GWA-57BR 730.26 651.42 641.42 32.27 697.99 76.0 86.0 Bedrock GWA-57BRU 729.66 691.09 681.09 25.60 704.06 36.0 46.0 Deep GWA-57S 729.43 713.28 708.28 11.24 718.19 14.0 19.0 Shallow GWA-58BR 732.56 654.03 644.03 27.30 705.26 76.0 86.0 Bedrock GWA-58BRU 731.83 698.60 693.60 16.46 715.37 31.0 36.0 Deep GWA-58S 731.74 724.20 714.20 14.39 717.35 4.8 14.8 Shallow GWA-59BR 756.06 679.82 674.82 27.98 728.08 73.9 78.9 Bedrock GWA-59D 756.53 717.42 707.42 28.65 727.88 36.2 46.2 Deep GWA-5BRU 776.73 734.69 729.69 21.38 755.35 40.0 45.0 Deep GWA-5S 777.01 760.93 745.93 20.81 756.20 14.0 29.0 Shallow GWA-60BR 763.87 706.40 696.40 23.75 740.12 55.5 65.5 Bedrock GWA-60BRU 763.99 739.67 729.67 18.17 745.82 22.0 32.0 Deep GWA-61BR 1 763.74 1 672.84 1 667.84 33.04 730.70 88.4 93.4 Bedrock GWA-61BRU 764.08 715.35 705.35 37.62 726.46 46.4 56.4 Deep GWA-62BR 735.10 679.30 669.30 62.56 672.54 1 56.0 66.0 Bedrock Page 4 of 6 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Elevation (ft. NAVD 88) April 2019Screen Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Frin low GWA-62BRU 734.65 713.08 708.08 7.89 726.76 22.0 27.0 Deep GWA-63BRU 815.37 746.86 736.86 51.80 763.57 66.0 76.0 Deep GWA-63S 815.08 767.29 762.29 50.29 764.79 46.0 51.0 Shallow GWA-64BRL 762.45 534.46 524.46 44.91 717.54 225.0 235.0 Bedrock GWA-65BR 754.33 685.12 675.12 23.73 730.60 66.1 76.1 Bedrock GWA-65BRL 754.07 401.23 391.23 15.22 738.85 350.0 360.0 Bedrock GWA-66BRL 771.11 513.29 493.29 22.93 748.18 254.0 274.0 Bedrock GWA-67BR 696.23 586.70 571.70 1.92 694.31 106.5 121.5 Bedrock GWA-67BRL 692.88 521.06 511.06 0.00 692.88 169.6 179.6 Bedrock GWA-68BRL 699.30 346.25 336.25 4.97 1 694.33 350.0 360.0 1 Bedrock GWA-61D 809.97 766.30 761.30 30.33 779.64 42.0 47.0 Deep GWA-6S 810.00 777.33 767.33 29.03 780.97 31.0 41.0 Shallow IB-61D 675.76 621.41 616.41 17.06 658.70 51.2 56.2 Deep IB-65 676.14 652.55 642.55 17.43 658.71 20.5 30.5 Shallow IB-7S 681.44 658.79 648.79 18.72 662.72 39.8 44.8 Shallow IB-71D 681.43 638.73 633.73 19.03 662.40 19.6 29.6 Deep MW-10D 785.50 750.06 745.06 27.41 758.09 32.8 37.8 Deep MW-105 785.81 763.70 748.70 27.63 758.18 19.7 34.7 Shallow MW-11BRL 767.462 469.05 459.05 60.79 706.67 295.2 305.2 Bedrock MW-11BRO 764.96 709.05 589.05 12.36 752.60 - - Bedrock MW-11D 763.67 723.45 718.45 - - 37.9 42.9 Deep MW-11DA 765.02 717.43 712.43 30.76 734.26 45.0 50.0 Deep MW-11S 764.51 747.10 732.10 28.45 736.06 15.0 30.0 Shallow MW-20D 665.20 656.13 641.13 6.25 658.95 6.5 21.5 Deep MW-20DR 665.38 650.26 600.26 0.00 665.38 12.5 62.5 Bedrock MW-21BR 777.56 694.40 689.40 14.35 763.21 81.1 86.1 Bedrock MW-21D 777.51 768.83 754.23 3.80 773.71 6.6 21.2 Deep MW-22BR 821.11 732.66 727.66 25.24 795.87 86.0 91.0 Bedrock MW-22DR 821.81 778.19 728.39 25.65 796.16 40.4 90.2 Bedrock MW-23D 734.08 695.09 685.09 16.61 717.47 36.0 46.0 Deep MW-23DR 733.80 685.69 635.69 15.63 718.17 45.0 95.0 Bedrock MW-23S 733.62 720.94 705.94 15.51 718.11 10.0 25.0 Shallow MW-24D 816.36 779.93 760.13 12.90 803.46 33.2 53.0 Deep MW-24DR 816.28 753.01 708.21 8.80 807.48 60.3 105.1 Bedrock MW-25DR 667.05 627.23 577.53 9.18 657.87 37.3 87.0 Bedrock MW-21DA 730.62 656.45 651.45 34.08 696.54 71.0 76.0 Bedrock MW-30D 833.26 745.02 740.02 40.05 793.21 86.1 91.1 Deep MW-30DA 835.05 741.64 736.64 43.57 791.48 87.0 92.0 Deep MW-30S 833.73 798.79 783.79 39.46 794.27 32.7 47.7 Shallow MW-32BR 839.40 769.42 764.42 24.30 815.10 62.5 72.5 Bedrock MW-32D 839.28 788.65 783.65 25.01 814.27 48.5 53.5 Deep MW-325 839.71 817.64 802.64 26.46 813.25 20.0 35.0 Shallow MW-34BRU 751.66 705.94 700.94 28.40 723.26 43.7 48.7 Deep MW-345 751.87 735.49 720.49 25.08 726.79 14.4 29.4 Shallow MW-36BRU 678.40 598.35 593.35 8.58 669.82 77.6 82.6 Deep MW-365 678.87 672.93 657.93 7.73 671.14 4.0 19.0 Shallow MW-38BR 707.70 610.47 605.47 38.68 669.02 97.5 102.5 Bedrock MW-38D 707.68 638.90 633.90 37.18 670.50 69.0 74.0 Deep MW-38S 707.60 670.17 655.17 38.43 669.17 37.7 52.7 Shallow MW-40BRU 709.56 679.69 674.69 4.09 705.47 30.4 35.4 Deep MW-40S 709.38 704.64 689.64 5.29 704.09 5.0 20.0 Shallow MW-42DA 812.02 759.44 754.44 34.26 777.76 49.3 54.3 Deep MW-42S 811.47 781.47 771.47 32.73 778.74 28.0 38.0 Shallow MW-81D 736.64 704.11 699.11 9.37 727.27 29.8 34.8 Deep MW-8S 736.27 730.88 715.88 6.13 730.14 2.9 17.9 Shallow MW-71D 807.35 771.09 766.09 40.74 766.61 33.5 38.5 Deep 1-15-11) 802.94 746.00 741.00 41.11 761.83 55.0 60.0 Deep U5-15 802.71 761.82 746.82 40.26 762.45 39.0 54.0 Shallow U5-2BR 795.06 700.06 695.06 59.44 735.62 100.3 105.3 Bedrock 1-15-21D 793.73 719.99 714.99 56.34 737.39 72.0 77.0 Deep U5-2S-SLA 795.42 742.39 727.39 50.97 744.45 50.0 65.0 Ash Pore Water U5-25-SLB 795.56 742.09 727.09 52.21 743.35 51.0 66.0 Ash Pore Water U5-4BR 765.06 639.90 634.90 75.85 689.21 125.1 130.1 Bedrock Page 5 of 6 TABLE 5-1 APRIL 2019 WATER LEVEL MEASUREMENTS AND ELEVATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Top of Casing Elevation (ft. NAVD 88) Top of Screen Elevation (ft. NAVD 88) Bottom of Screen Elevation (ft. NAVD 88) April 2019 Measured Water Level (ft. BOTC) April 2019 Water Elevation (ft. NAVD 88) Screened Interval (Ft-BGS) Monitoring Zone Flow U5-4BRA 765.11 636.34 626.34 17.80 747.31 129.0 139.0 Bedrock US-41) 764.99 661.23 656.23 53.83 711.16 104.2 109.2 Deep U5-4S 764.82 705.59 690.59 50.60 714.22 59.8 74.8 Shallow U5-5BR 765.66 660.12 655.12 62.35 703.31 105.5 110.5 Bedrock U5-5D 765.40 700.98 695.98 57.69 707.71 65.5 69.5 Deep US-61) 765.19 708.93 703.93 46.36 718.83 56.5 61.5 Deep U5-6S 765.28 728.64 713.64 46.92 718.36 37.0 52.0 Shallow U5-8BR 770.31 649.64 644.64 3.28 767.03 120.9 125.9 Bedrock U5-8D 770.25 699.57 694.57 7.40 762.85 71.0 76.0 Deep U5-85 1 770.29 1 765.63 1 750.63 5.54 764.75 1 5.0 20.0 Shallow Notes: -- not measured or not available BGS - below ground surface Ft - Feet NAVD 88 - North American Vertical Datum 1988 Prepared by: AKM Checked by: VJH Page 6 of 6 TABLE 5-2 GROUNDWATER BALANCE SUMMARY CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Modeling Scenario Pre- Closure -in- Closure -by - Decanting Place Excavation c E 3 o c E 3 o c E 3 o f Water Balance Components n 00 3 0 a oo, 3 a a oa, 3 a oa, orn orn Recharge from capped areas 10 Flow removed by Unit 5 10 56 18 Leakage from AAB to GW 65 Flow removed by streams or drains in AAB and ASA 114 54 Recharge from Suck Creek to groundwater system 4 17 9 Flow removed by surface water and private wells 337 251 287 Recharge from watershed 562 567 511 Flow removed by General Head Edge of model 24 24 26 Prepared by: SAS Checked by: TJG Notes: 1) Drainage includes streams, seeps, ditch, channel, canal, etc. Drainage streams included are depending on the scenario, where the pre -decanting scenario includes streams present prior to closure and closure -by excavation includes streams that form within the excavated ash basin footprint after closure. 2) Other refers to groundwater flow in/out the watershed that are not accounted in the above categories Flow in refers to recharge to the groundwater system Flow out refers to discharge from the groundwater system gpm - gallons per minute Page 1 of 1 TABLE 5-3 SURFACE WATER CLASSIFICATIONS CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Adjacent Surface Water Body Surface Water Classification (15A NCAC 02B .0300) Broad River Class WS-IV Suck Creek Class WS-IV Unnamed Tributary west of U5 AB Class WS-IV Prepared by: SAS Checked by: TJG Notes• 1. Class C waters are protected for uses such as secondary recreation, fishing, wildlife, fish consumption, aquatic life including propagation, and survival. 2. Class WS-IV waters are protected as water supplies that are generally in moderately to highly developed watersheds. WS-IV waters are also subject to Class C water quality standards. Page 1 of 1 Corrective Action Plan Update December 2019 Cliffside Steam Station Source Area 1 SynTerra (Active Ash Basin and Ash Storage Area) TABLE 6-1 BORON CONCENTRATIONS IN GROUNDWATER BELOW SOURCE AREA ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Boron Boron Well Beneath Number Time Period Concentration Concentration Range in Ash of Sample of Record Range in Overlying Pore (Flow Zone) Events Groundwater Water (pg/L) (pg/L) AB-3BRA (Bedrock) 3 11/2018 - 04/2019 <501 <50 - 4,990 AB-3BRU/BRUA 17 06/2015 - 04/2019 <50 - 72.5 (Deep) (-30' saturated ash) AB-3I (Shallow) 16 06/2015 - 04/2019 <50 - 94.4 AB-4BR 15 06/2015-04/2019 <50 - 70 (Bedrock) 449 - 3,000 (-25' saturated ash) AB-4D (Deep) 16 06/2015 - 04/2019 <501 AB-5BR 12 03/2016 - 01/2019 <501 (Bedrock) 2,940 - 6,150 (-45' saturated ash) AB-5BRU 14 06/2015 - 01/2019 <501 AB-6BR (Bedrock) 15 06/2015 - 01/2019 <501 1,960 - 11,300 <50 (-35' saturated ash) AB-6D 15 06/2015 - 01/2019 (one anomalous (Deep) concentration of 114) AB-7BR 2 04/2019 - 06/2019 90 - 93 (Bedrock) 1,630 - 1,890 (-25' saturated ash) AB-7BRU 3 04/2019 - 07/2019 89.7 - 100 (Deep) AB-8BR 2 03/2019 - 06/2019 331 - 341 (Bedrock) 4,330 - 4,390 AB-8BRU 2 03/2019 - 06/2019 417 - 459 (Deep) (-35' saturated ash) AB-8I 2 03/2019 - 06/2019 807 - 811 (Shallow) AB-9BR 2 03/2019 - 06/2019 <501 (Bedrock) 5,600 - 6,220 (-15' saturated ash) AB-9D 2 03/2019 - 06/2019 73 - 81 (Deep) Prepared by: TJG Checked by: SAS Notes: < - Concentration not detected at or above the adjusted reporting limit 1 - Concentrations have not been detected at or above the adjusted reporting limit across all sampling events Page 1 of 1 TABLE 6-2 SOIL PSRG POG STANDARD EQUATION PARAMETERS AND VALUES CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Csoii = Cgw [Kd + (G. + 6aH')/Pb]df Inorganic Parameter Definition Default Values Units Parameters Csoil Calculated source concentrations for soil NA mg/kg C9'"' Applicable groundwater target 15A NCAC 02L mg/L concentration: 15A NCAC 02L Standard Standard df Dilution factor' 20 unitless Kd Soil -water partition coefficient for Constituent Specific4 L/kg inorganics (range) OW Effective porosity - water filled soil porosity 0.3 Lwater/Lsoii vadose soils 9a Total porosity - Air filled soil porosity - 0.13 Lair/Lso;i vadose soils Pb dry bulk density2 1.6 kg/L Henry's law constant -dimensionless where: H' H' = Henry's law constant (atm - m3/mole) Constituent Specific3-5 unitless x conversion factor of 41 Prepared by: SAS Checked by: TJG Notes: ' - Default value from Soil Screening Guidance: Technical Background Document (USEPA, 1996) z - Site specific value (Falta et al., 2019). Effective porosity represents unconsolidated material. 3 - DEQ default value appropriate for North Carolina 4 - Constituent Specific- Soil water partition coefficients (Kd) were obtained from the Groundwater Quality Signatures for Assessing Potential Impacts from Coal Combustion Product Leachate (EPRI, 2012). Sulfate Kd ranges from 0.1 to 2.1, based on sands/sediments and a pH range of 4.6 to 7.2 5 - a value of 0 is used for sulfate NA - Not applicable NCAC - North Carolina Administrative Code mg/kg - milligrams per kilogram mg/L - milligrams per liter L/kg - liters per kilogram Lwater/Lson - volume of water filled spaces per volume of soil Lair/LSo;i - volume of air filled spaces per volume of soil kg/L - kilogram per liter Page 1 of 1 TABLE 6-3 SUMMARY OF UNSATURATED SOIL ANALYTICAL RESULTS ACTIVE ASH BASIN CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameters pH Arsenic Boron Cobalt Iron Manganese Strontium Sulfate Thallium Vanadium Reporting Units S.U. mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater NE 5.8 45 0.9 150 65 1,500 1,438 0.28 350 Background Threshold Values 4.0-6.8 7.8 31 48 74,362 672 9.9 13 1.1 161 Sample ID Sample Collection Date Analytical Results Background BGSB-BG-1 (6-7) 10/19/2017 5.0 1.2 <5.1 23 40,000 B 260 1.5 13 0.64 84 BGSB-BG-1 (13-14) 10/19/2017 4.8 0.49 <5.2 6 16,000 B 130 lj <11 0.4 42 BGSB-BG-1 (19-20) 10/19/2017 4.6 3 <25 5.2 38,000 B 48 <9.9 <12 0.33 40 BGSB-BG-2 (2-3) 10/19/2017 5.1 6.8 <11 4.1 47,000 B 100 1.2 47 0.29 110 BGSB-BG-2 (6-7) 10/19/2017 5.2 1.3 <12 13 49,000 B 200 <4.7 <13 0.19 120 BGSB-GWA-25 (6-7) 10/19/2017 4.9 1.5 <13 15 52,000 B,M 93 3.7 j <12 0.65 120 BGSB-GWA-25 (14-15) 10/19/2017 5.2 2.8 <5.1 23 15,000 B 850 1.7 j <12 M 0.3 44 GWA-25D (8.5 - 10) 05/11/2015 5.1 j <5.6 <14 11.8 23,500 254 <2.8 <268 <5.6 51.4 Beyond Ash Basin Waste Boundary AS-1D (3.5 - 5) 05/13/2015 5.3 j <7.1 9 j 8.6 12,800 357 <3.5 <347 <7.1 15.8 AS-1D (28.5 - 30) 05/13/2015 6.1 j <7 16.6 j 10.4 22,800 300 3 j <356 <7 32.4 AS-1D (58.5 - 60) 05/13/2015 7.2 j <6.9 <17.2 <6.9 3,120 22.4 8.2 <338 <6.9 <6.9 AS-1D (68.5 - 70) 05/13/2015 5.5 j <7 <17.4 <7 4,310 30 4.3 <350 <7 <7 AS-4D (63.5 - 65) 05/05/2015 5.63 <6.6 <16.6 <6.6 6,690 148 2.1 j <323 <6.6 <6.6 AS-5BRU (33.5 - 35) 04/10/2015 6.5 j <6.1 <15.3 <6.1 3,280 95.7 <3.1 <295 <6.1 <6.1 AS-6D (48.5 - 50) 04/30/2015 5.3 j 5.7 j 12.4 j 22.1 14,700 944 <3.1 <323 <6.3 20.9 AS-7D (3.5 - 5) 05/18/2015 5.1 j <7.7 14.5 j 6.5 j 20,900 168 <3.9 <374 <7.7 24.6 BG-1D (3.5 - 5) 02/23/2015 5.4 j <3 <3 7.5 1 35,900 75.2 4.4 <314 <1.2 59.7 BG-1D (8.5 - 10) 02/23/2015 5.7 j 1.4 <13.3 8.1 17,400 64.7 7.6 <267 0.7 j 31 GWA-20D (3 - 5) 04/23/2015 7.8 j <5 <12.6 2.9 j 5,150 225 2.1 j <264 <5 10.2 GWA-21BRU (5 - 5) 05/08/2015 7.8 j 2.9 j <14 7.1 19,200 242 5.4 224 j- <5.6 22.7 GWA-21BRU (10 - 10) 05/08/2015 5.5 j 3.6 j <14.8 31.3 23,600 243 3.9 239 j- <5.9 26.7 GWA-22S (3 - 5) 05/04/2015 9.2 j <8.1 <20.2 6.6 j 27,900 256 3.9 j <407 <8.1 50.4 GWA-23D (15.8 - 15.8) 05/08/2015 4.2 j <5.1 <12.7 21.2 36,800 170 <2.5 <256 <5.1 22.4 GWA-26D (13.5 - 15) 05/07/2015 5.9 j <6.3 <15.7 5.9 j 16,200 189 <3.1 <322 <6.3 17.8 GWA-27D (13.5 - 15) 03/03/2015 5.5 j 0.95 j 16.1 73.3 17,600 1,240 0.39 j <292 0.74 j 23.8 GWA-27D (24.9 - 24.9) 06/08/2015 5.6 j 4.8 j <12.7 73.8 24,900 1,190 <2.5 <252 <5.1 30.3 Prepared by: TJG Checked by: VJH Notes• 0 - Bold highlighted concentration indicates exceedance of the Inactive Hazardous Sites Branch PSRG Table (May 2019) for Protection of Groundwater or the Background Threshold Value (BTV), whichever is higher. < - Concentration not detected at or above the adjusted reporting limit. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 10X the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j- Estimated concentration, biased low. M - Matrix spike / matrix spike dup failure. mg/kg - milligrams per kilogram NE - not established PSRG - preliminary soil remediation goals S.U. - standard units Page 1 of 1 TABLE 6-4 SOURCE AREA INTERIM ACTIONS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Groundwater Remedy Component Rationale Active source remediation by removing ponded water in the AAB. Decanting will lower the hydraulic head within the coal ash basin Active Ash Basin and reduce hydraulic gradients, reducing groundwater seepage Decanting velocities and COI transport potential. Decanting will return the groundwater flow system to its approximate condition, prior to construction of the ash basin, with the re-establishment of the former Suck Creek stream channel. Source Area AAB downstream dam modifications including spillway and riser Stabilization repair and the installation of a new spillway. Notes: COI - Constituent of Interest Prepared by: SAS Checked by: TJG Page 1 of 1 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 ACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L mg/L Ng/L mg/L pCi/L Ng/L Ng/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 - 6.1 1 50 0.5 4 1 11 684 NE 1 169 37 1 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone )2 4.0 - 6.0 0.2 50 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range Shallow Flow Zone z 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7 - 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 10700 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 - 6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone )2 4.9 - 7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range (Deep Flow Zone z 3.8 - 7.3 <0.1 -2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4- 7.4 1 50 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone )2 4.5 - 7.5 1 50 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range Bedrock Flow Zone)2 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 S - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID Flow Zone Mean, Geomean, or Median Result3 Background Locations BG-01S Shallow 4.9 < 0.1 < 50 0.230 0.9 1.7 171 1.6 39 21 1 < 0.1 41 0.538 < 0.0005 < 0.3 GWA-24S Shallow 5.1 0.1 < 50 0.134 1.4 5.2 113 2.0 52 10 2 < 0.1 30 < 0.732 - 0.5 GWA-25S Shallow 5.2 < 0.1 < 50 0.094 < 0.5 2.7 88 1.7 26 36 < 1 < 0.1 38 - - < 0.3 BG-01D Deep 5.7 0.1 < 50 0.045 < 0.5 0.6 < 50 1.7 12 30 2 < 0.1 56 0.772 < 0.0005 < 0.3 GWA-24D Deep 5.5 < 0.1 < 50 0.032 < 0.5 0.2 < 50 1.7 5 24 3 < 0.1 45 < 0.443 - < 0.3 BG-0113RA Bedrock 11.5 - < 50 - - - - - - - - - - - - GWA-24BR Bedrock 6.0 < 0.1 < 50 0.038 < 0.5 0.1 54 2.8 < 5 29 7 < 0.1 52 - < 0.3 MW-22BR Bedrock 6.4 0.1 < 50 0.084 < 0.5 1.0 369 2.7 49 43 8 < 0.1 67 - 0.3 MW-22DR Bedrock 5.8 < 0.1 < 50 0.036 < 0.5 1.2 511 2.3 52 24 5 < 0.1 39 < 0.3 MW-24DR Bedrock 7.2 < 0.1 < 50 0.033 0.5 < 0.1 1297 6.9 58 80 11 < 0.1 108 2.134 < 0.0005 < 0.3 Within the Waste Boundary Locations AB-03MAIS Ash Pore Water 9.6 282 1708 < 0.025 0.7 < 0.1 < 50 210 < 5 1358 112 < 0.1 327 < 0.0939 0.0003 109 AB-03S Ash Pore Water 7.4 372 2970 < 0.025 1.0 1.0 4268 119 1185 3007 386 0.7 975 0.564 0.0027 5.1 AB-03SL Ash Pore Water 9.6 851 1138 < 0.025 1.1 0.1 128 198 32 897 66 < 0.1 191 1.207 0.0001 75.8 AB-04LAIS Ash Pore Water 5.6 184 606 0.051 0.6 5.4 4108 14.5 686 354 1 0.3 77 1.420 0.0001 1.4 AB-04S Ash Pore Water 9.4 92.6 2513 < 0.025 < 0.5 0.1 < 50 119 < 5 2207 127 < 0.1 471 0.784 0.0006 41.8 AB-04SL Ash Pore Water 9.0 1692 1506 0.051 0.7 0.1 97 56.5 9 1640 31 < 0.1 172 0.415 0.0056 45.9 AB-04UA15 Ash Pore Water 10.0 92.3 2913 < 0.025 0.8 < 0.1 < 50 141 < 5 2270 126 < 0.1 470 1.190 0.0001 38.9 AB-05S Ash Pore Water 8.0 1782 5242 < 0.025 < 0.5 0.1 1728 92.4 211 3540 88 < 0.1 423 1.146 0.1167 1.6 AB-06S Ash Pore Water 8.6 323 8380 0.058 < 0.5 < 0.1 161 103 46 2510 111 < 0.1 377 0.946 0.0010 8.9 AB-07S Ash Pore Water 9.2 157 1760 0.048 0.7 0.1 < 50 133 11 1430 97 0.1 352 < 0.695 0.0017 52.0 AB-08S Ash Pore Water 7.9 65.1 4360 0.033 < 0.5 0.4 120 151 73 2775 842 1.0 1605 < 0.851 0.0725 52.5 AB-09S Ash Pore Water 8.6 1965 5910 0.071 < 0.5 < 0.1 119 106 43 2335 139 < 0.1 415 0.329 0.0019 0.7 AB-01S Shallow 5.2 0.3 50 < 0.025 < 0.5 68.6 1478 2.5 6045 32 4 0.5 110 - 0.0001 0.4 AB-02S Shallow 5.5 0.8 330 < 0.025 1.9 39.7 9102 2.8 17598 76 24 0.3 124 - 0.5 AB-03I Shallow 6.6 3.1 50 0.447 1.1 0.2 156 5.8 127 131 3 0.4 70 - - 2.4 AB-08I Shallow 6.4 3.1 809 < 0.025 < 0.5 11.8 24250 1.8 10570 109 24 0.1 201 0.750 0.0004 < 0.3 CLMW-05S Shallow 5.2 0.2 < 50 < 0.025 0.4 56.6 294 0.9 4790 25 4 0.4 65 - - < 0.3 AB-01D Deep 6.6 0.2 804 < 0.025 1.3 1.1 9187 4.5 2317 256 36 < 0.1 302 - 0.4 AB-02D Deep 6.7 0.1 291 0.027 2.5 2.6 17746 15.3 2524 345 50 < 0.1 259 - < 0.3 AB-03BRUA Deep 11.4 - 60 - - - - - - - - - - - - AB-04D Deep 4.6 0.1 < 50 0.095 < 0.5 5.3 55 1.9 180 8 < 1 < 0.1 30 < 0.0005 < 0.3 A13-0513RU Deep 5.4 0.4 < 50 0.031 < 0.5 3.5 104 2.3 171 38 5 0.1 43 - 0.3 AB-06D Deep 5.2 0.1 < 50 0.027 < 0.5 0.6 < 50 1.6 38 29 < 1 < 0.1 34 - < 0.0005 < 0.3 AB-07BRU Deep 7.4 - 94 - - - - - - - - - - - - - AB-08BRU Deep 6.6 0.5 438 < 0.025 1.5 1.4 1357 14.4 245 172 9 < 0.1 237 1.164 0.0015 0.4 AB-09D Deep 5.9 0.2 77 0.039 0.6 12.0 580 3.4 254 42 3 0.1 48 0.777 0.0001 0.3 AB-01BROR Bedrock 7.0 0.2 397 0.034 15.1 3.8 1550 6.9 1555 268 11 < 0.1 364 - - AB-02BRO Bedrock 6.9 0.9 476 < 0.025 2.1 8.7 12352 1.8 2188 517 53 < 0.1 292 0.4 AB-03BR Bedrock 12.4 - 46 - - - - - - - - - - - AB-03BRA Bedrock 12.5 33 - - - - - - - - - - - - - AB-04BR Bedrock 6.3 < 0.1 < 50 < 0.025 < 0.5 < 0.1 11847 5.8 155 105 4 < 0.1 120 2.037 < 0.0005 < 0.3 AB-05BR Bedrock 5.5 0.1 < 50 0.029 0.4 1.7 49 1.6 109 23 6 < 0.1 47 - - < 0.3 AB-06BR Bedrock 6.3 < 0.1 < 50 1 0.026 1 0.5 < 0.1 4214 9.1 69 SOS 5 < 0.1 1 89 1 - < 0.0005 < 0.3 AB-07BR Bedrock 7.8 0.4 92 1 < 0.025 1 2.5 0.2 1018 10.6 168 168 5 < 0.1 1 163 1 3.285 1 0.0003 1 0.3 Page 1 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 ACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L pg/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 - 6.1 1 So 0.5 4 1 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone )2 4.0 - 6.0 0.2 So 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range Shallow Flow Zone z 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7 - 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 10700 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 - 6.1 1 So 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone)z 4.9 - 7.2 2 So 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range Dee Flow Zone Z 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4 - 7.4 1 So 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone )2 4.5 - 7.5 1 So 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range Bedrock Flow Zone z 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID I Flow Zone Mean, Geomean, or Median Result3 Within the Waste Boundary Locations (Continued) AB-08BR Bedrock 6.4 0.8 336 < 0.025 0.9 1.3 2095 8.0 577 164 13 < 0.1 246 1.101 0.0010 0.2 AB-09BR Bedrock 7.4 0.3 < 50 < 0.025 0.6 0.2 2035 8.3 91 93 15 < 0.1 117 0.661 0.0001 0.3 Between Waste Boundary and Compliance Boundary Upgradient of the Ash Basin GWA-23D Deep 5.2 < 0.1 < 50 0.062 < 0.5 0.8 < 50 1.7 9 16 < 1 < 0.1 61 - - < 0.3 MW-21D Deep 5.1 0.1 < 50 0.077 < 0.5 0.9 178 1.5 12 22 2 < 0.1 33 - - < 0.3 MW-24D Deep 5.2 0.2 < 50 0.059 < 0.5 0.1 < 50 1.6 < 5 26 < 1 < 0.1 41 0.427 < 0.0005 < 0.3 CCR-17BR Bedrock 6.0 < 0.1 < 50 < 0.025 2.0 2.0 143 2.1 47 33 6 < 0.1 68 0.906 < 0.0005 0.3 GWA-48BR Bedrock 6.7 < 0.1 < 50 < 0.025 0.6 < 0.1 2300 6.3 49 66 11 < 0.1 91 - - < 0.3 MW-21BR Bedrock 6.9 0.2 < 50 0.029 < 0.5 < 0.1 < 50 4.0 55 53 8 < 0.1 99 0.3 Downgradient of the Ash Basin CCR-06S Shallow 4.3 7.0 1317 - 2.5 97.6 - 9.1 - - 508 0.5 867 3.664 - CCR-07S Shallow 6.6 0.2 2714 0.042 0.6 3.0 70 0.9 5496 2648 495 0.5 1153 0.776 < 0.3 CCR-11S Shallow 7.1 0.1 1207 - < 0.5 0.5 - 0.8 - - 125 < 0.1 476 0.624 - CCR-12S Shallow 5.0 0.4 1144 3.475 4.7 16.5 300 3.7 3512 74 47 0.2 177 2.310 < 0.3 CCR-16S Shallow 4.4 0.9 2580 - 1.1 77.5 - 2.8 - - 76 0.2 174 1.493 - - CLMW-01 Shallow 4.7 0.8 1420 0.203 3.1 2.4 224 1.2 213 895 111 0.5 318 1.446 < 0.0005 < 0.3 CLMW-06 Shallow 5.0 < 0.1 < 50 0.123 < 0.5 11.5 144 1.1 165 17 < 1 < 0.1 34 - - < 0.3 GWA-20S Shallow 6.4 0.2 283 0.104 0.6 13.3 968 < 0.5 6013 149 92 < 0.1 349 0.487 < 0.0005 < 0.3 GWA-26S Shallow 4.8 0.1 < 50 0.032 0.6 0.8 243 1.1 22 < 5 < 1 < 0.1 < 25 - - < 0.3 GWA-28S Shallow 4.8 0.2 < 50 0.109 1.1 2.3 244 1.8 35 5 2 0.1 30 0.3 GWA-42S Shallow 5.3 < 0.1 29 0.120 < 0.5 0.7 41 - 14 87 49 < 0.1 81 < 0.3 GWA-43S Shallow 5.1 0.1 79 0.464 0.9 1.3 174 0.9 21 167 44 < 0.1 92 - - < 0.3 GWA-57S Shallow 5.5 0.1 < 50 < 0.025 < 0.5 14.5 246 2.9 1855 132 99 < 0.1 207 0.518 0.0004 0.3 GWA-58S Shallow 5.6 0.1 < 50 1.700 1.4 4.2 40 2.2 1890 175 245 0.1 510 < 1.14 < 0.0005 0.3 GWA-63S Shallow 5.8 < 0.1 < 50 0.290 31.6 2.8 188 2.4 485 13 1 0.1 32 < 0.855 < 0.0005 < 0.3 MW-08S Shallow 7.0 0.3 206 0.025 1.0 3.6 1123 < 0.5 2910 134 57 < 0.1 310 0.976 0.0002 0.4 MW-10S Shallow 5.1 0.5 216 0.552 1.0 1.6 334 2.1 197 56 60 0.1 189 0.652 - 0.3 MW-11S Shallow 5.3 0.2 766 1.617 6.0 1 1.2 235 2.1 1754 47 40 < 0.1 230 0.672 < 0.0005 < 0.3 CCR-04D Deep 5.4 0.1 56 - 0.5 0.8 - 1.0 - - 22 0.1 84 0.753 - - CCR-05D Deep 5.2 0.2 55 < 0.5 10.7 1.7 12 0.1 88 0.570 CCR-06D Deep 5.0 1.4 1464 - 2.6 5.9 - 4.0 - - 196 0.4 361 1.077 - CCR-07D Deep 5.6 < 0.1 616 0.139 < 0.5 < 0.1 < 50 1.1 99 155 35 0.3 146 1.247 - < 0.3 CCR-08D Deep 5.2 7.2 1991 0.051 < 0.5 294 < 50 4.4 8995 1350 328 1.5 673 1.355 < 0.0005 < 0.3 CCR-09D Deep 4.7 2.1 838 - 0.7 83.0 - 2.1 - - 321 0.1 461 0.716 - - CCR-11D Deep 6.8 0.1 1210 - < 0.5 2.1 - < 0.5 - - 94 0.2 379 0.837 - CCR-12D Deep 6.2 0.2 373 0.028 1.2 9.4 13800 6.6 1037 76 25 < 0.1 173 1.540 < 0.3 CCR-13D Deep 5.0 < 0.1 54 0.028 < 0.5 1.5 82 2.0 35 14 3 < 0.1 41 < 0.646 < 0.3 CCR-14D Deep 4.7 0.3 1095 - < 0.5 1.6 - 3.5 - - 65 0.2 259 1.260 - CCR-15D Deep 4.8 < 0.1 117 < 0.025 1.0 3.6 < 50 0.9 102 10 < 1 < 0.1 39 < 0.626 < 0.3 CCR-16D Deep 6.2 0.1 30 - < 0.5 0.2 - 4.4 - - 3 < 0.1 68 0.716 - - GWA-20D Deep 5.7 0.2 921 0.041 < 0.5 100 1664 2.0 6015 549 178 0.7 433 1.551 < 0.0005 < 0.3 GWA-27DA Deep 5.1 0.2 980 0.127 0.7 0.8 97 1.5 1296 107 65 0.2 261 0.510 < 0.0005 < 0.3 GWA-28BRU Deep 6.3 0.3 < 50 0.029 0.5 5.5 7330 9.6 53 50 11 < 0.1 98 - - < 0.3 GWA-43D Deep 6.3 0.1 < 50 0.128 0.7 0.3 < 50 21.5 < 5 165 81 < 0.1 253 - - 0.7 GWA-51D Deep 5.1 1.2 796 0.526 1.9 71.3 141 3.4 8184 237 229 0.3 486 5.815 < 0.0005 0.3 Page 2 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 ACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. pg/L Ng/L pg/L pg/L pg/L pg/L Ng/L pg/L Ng/L mg/L pg/L mg/L pCi/L pg/L pg/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 -6.1 1 50 0.5 4 1 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone )2 4.0 - 6.0 0.2 50 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range Shallow Flow Zone z 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7- 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 10700 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 -6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone)z 4.9-7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range Dee Flow Zone Z 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4- 7.4 1 50 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone )2 4.5 - 7.5 1 50 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range Bedrock Flow Zone z 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID I Flow Zone Mean, Geomean, or Median Result3 Downgradient of the Ash Basin (Continued) GWA-57BRU Deep 6.9 1.3 78 < 0.025 < 0.5 3.3 1330 15.1 286 293 167 < 0.1 492 15.405 0.0083 0.9 GWA-58BRU Deep 5.9 0.3 < 50 < 0.025 < 0.5 11.7 3140 5.0 720 274 260 0.1 507 1.769 0.0006 < 0.3 GWA-59D Deep 5.5 0.7 597 0.166 1.2 118 1210 7.4 9850 200 187 0.3 379 1.933 0.0001 0.4 GWA-63BRU Deep 6.6 0.4 115 < 0.025 1.6 2.3 643 10.3 390 91 8 < 0.1 153 0.558 0.0002 0.3 MW-08D Deep 6.0 < 0.1 130 0.034 < 0.5 4.8 35460 6.7 5356 106 52 < 0.1 212 4.600 < 0.0005 < 0.3 MW-10D Deep 5.1 < 0.1 153 0.120 0.9 2.0 193 2.6 92 51 16 0.1 69 0.858 - 0.3 MW-11DA Deep 6.9 0.5 79 0.048 2.2 51.0 5012 9.4 252 145 38 < 0.1 327 2.833 0.3 CCR-03BR Bedrock 6.1 0.5 12 - 3.7 0.8 - 2.9 - - 7 < 0.1 110 1.124 - - CCR-08BR Bedrock 5.4 0.2 901 < 0.025 1.2 4.7 541 1.4 2265 306 65 0.4 243 1.332 < 0.0005 < 0.3 CCR-12BR Bedrock 6.3 0.3 38 < 0.025 1.7 0.6 1001 6.4 278 115 17 < 0.1 179 0.725 < 0.0005 < 0.3 GWA-20BR Bedrock 8.3 0.7 258 0.027 < 0.5 0.3 8625 27.7 489 524 82 < 0.1 283 3.673 0.0002 < 0.3 GWA-27BR Bedrock 6.5 0.3 258 0.029 1.4 0.1 997 19.0 29 206 5 < 0.1 198 1.255 0.0019 < 0.3 GWA-28BR Bedrock 6.6 0.1 < 50 0.031 0.4 0.4 5662 5.3 83 80 7 < 0.1 119 - - < 0.3 GWA-57BR Bedrock 7.2 0.1 231 < 0.025 2.6 0.6 305 3.2 965 199 64 < 0.1 324 5.715 0.0009 0.6 GWA-58BR Bedrock 6.7 < 0.1 366 < 0.025 0.6 0.3 19350 11.0 1034 241 124 < 0.1 342 10.370 0.0004 < 0.3 GWA-59BR Bedrock 5.8 0.2 593 < 0.025 0.7 2.1 4760 15.9 922 304 144 < 0.1 366 3.221 0.0001 < 0.3 GWA-64BRL Bedrock 7.8 0.6 236 < 0.025 < 0.5 0.1 5675 43.5 576 436 21 < 0.1 348 3.220 0.0011 < 0.3 GWA-65BR Bedrock 10.9 - 381 - - - - - - - - - - - - - GWA-65BRL Bedrock 12.8 - 83 - - - - - - - - - - - - GWA-66BRL Bedrock 7.5 0.1 403 < 0.025 < 0.5 0.2 1480 28.8 299 395 17 < 0.1 292 7.135 0.0001 < 0.3 MW-11BRL Bedrock 10.8 - 38 - - - - - - - - - - - - - MW-11BRO Bedrock 6.6 < 0.1 108 < 0.025 1 0.9 0.3 11700 6.5 1497 129 8 < 0.1 1 279 4.270 0.3 Near or Beyond Compliance Boundary Downgradient of the Ash Basin AS-07S Ash Pore Water 7.2 83.7 1447 < 0.025 1.6 3.5 14176 85.9 12196 2828 497 1.3 1078 0.650 0.0051 1.8 AS-08S Ash Pore Water 6.7 58.2 147 0.067 0.7 2.4 4414 6.4 2923 1318 28 0.2 247 - - 0.5 AS-01SB Shallow 4.3 6.1 1596 0.158 1.4 14.5 222 8.3 913 113 273 0.6 537 - 0.0011 < 0.3 AS-02S Shallow 4.5 5.6 1003 0.609 1.6 16.8 < 50 2.4 9650 202 315 0.4 594 0.823 < 0.0005 < 0.3 AS-04S Shallow 5.9 0.3 < 50 0.255 14.8 2.0 336 3.4 107 45 3 0.1 76 - - 0.5 AS-05S Shallow 5.3 0.3 < 50 0.057 1.0 0.2 215 2.9 19 7 < 1 < 0.1 28 - < 0.0005 < 0.3 AS-06S Shallow 5.4 < 0.1 < 50 0.150 2.5 0.3 219 1.7 100 12 < 1 < 0.1 33 0.474 - < 0.3 AS-07I Shallow 5.5 3.9 645 0.029 < 0.5 15.5 3913 4.9 6477 177 209 0.7 447 < 1.27 0.0002 < 0.3 CLMW-02 Shallow 4.1 1.1 538 0.105 0.8 18.5 88 5.6 1530 92 226 0.4 451 - - < 0.3 CLMW-03S Shallow 4.2 3.9 911 0.091 0.7 37.1 127 9.3 3425 36 253 0.3 498 < 0.833 < 0.0005 0.4 CLP-01 Shallow 5.2 0.3 204 0.110 0.6 2.2 326 - 101 36 14 0.2 58 - - 0.5 CLP-02 Shallow 5.7 0.1 47 < 0.025 5.9 2.5 368 - 123 27 18 < 0.1 70 - - 0.3 GWA-21S Shallow 9.4 10.4 158 0.453 1.5 0.6 72 3.0 23 204 96 0.3 259 0.507 0.0006 6.2 GWA-22S Shallow 5.5 0.1 264 0.032 1.3 1.6 468 1.2 43 67 3 < 0.1 103 0.797 < 0.0005 1.1 GWA-33S Shallow 4.9 0.2 < 50 0.030 1.1 14.6 6566 6.2 546 142 97 < 0.1 179 - 0.0000 0.4 GWA-54S Shallow 4.9 < 0.1 75 0.044 1.0 6.9 137 2.8 219 21 < 1 0.2 58 1.219 < 0.0005 < 0.3 MW-23S Shallow 4.9 0.1 < 50 2.360 3.0 1.1 150 2.2 64 120 121 0.1 219 - - < 0.3 AS-01D Deep 5.5 0.1 672 0.444 2.1 0.4 157 2.5 291 186 56 0.3 167 - < 0.0005 0.3 AS-02D Deep 7.3 1.3 343 0.072 1.5 0.5 286 28.5 471 533 217 < 0.1 463 1.367 < 0.0005 0.7 AS-03BRU Deep 5.2 < 0.1 < 50 < 0.025 0.9 0.1 229 1.8 13 19 < 1 < 0.1 36 - - < 0.3 AS-04D Deep 5.4 0.1 < 50 1 0.333 1.3 0.7 107 6.2 39 29 1 < 0.1 62 0.710 - 0.4 AS-05BRU Deep 5.8 0.2 < 50 0.068 1.8 0.2 271 0.8 12 22 < 1 < 0.1 41 - < 0.0005 0.3 AS-06D Deep 5.6 < 0.1 < 50 0.068 0.9 0.2 126 0.9 11 29 < 1 < 0.1 50 0.747 - < 0.3 Page 3 of 4 TABLE 6-5 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 ACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. pg/L Ng/L pg/L pg/L pg/L pg/L Ng/L pg/L Ng/L mg/L pg/L mg/L pCi/L pg/L pg/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 -6.1 1 50 0.5 4 1 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone )2 4.0 - 6.0 0.2 50 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range Shallow Flow Zone z 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7 - 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 10700 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 -6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone)z 4.9 - 7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range Dee Flow Zone 2 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4 - 7.4 1 50 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone )2 4.5 - 7.5 1 50 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range Bedrock Flow Zone z 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID I Flow Zone Mean, Geomean, or Median Result3 Downgradient of the Ash Basin (Continued) AS-07D Deep 5.5 0.2 836 0.266 1.5 0.3 122 7.7 1950 259 129 0.1 305 - - < 0.3 AS-08D Deep 6.1 0.5 798 < 0.025 2.0 8.2 4310 3.8 4968 280 185 < 0.1 429 - - < 0.3 AS-09D Deep 5.9 0.4 138 0.107 4.2 30.8 265 1.6 470 34 4 0.1 73 < 0.866 < 0.0002 0.5 CLMW-03D Deep 5.2 0.2 912 0.135 1.1 0.2 283 4.2 43 295 280 < 0.1 529 1.351 < 0.0005 0.3 GWA-21BRU Deep 6.5 < 0.1 156 < 0.025 < 0.5 1.0 516 1.9 168 174 23 0.1 200 1.184 < 0.0005 < 0.3 GWA-22BRU Deep 8.0 0.3 < 50 0.069 0.7 < 0.1 174 11.7 11 128 4 < 0.1 146 0.536 - 0.8 GWA-33D Deep 6.1 0.2 < 50 0.044 0.4 0.4 709 24.2 89 169 106 < 0.1 278 - 0.4 GWA-47D Deep 5.3 0.1 333 0.064 0.9 1.1 161 2.8 140 70 < 1 0.1 88 1.063 - 0.6 GWA-54D Deep 7.3 0.5 74 0.047 1.0 0.1 851 4.9 210 230 48 < 0.1 292 0.552 < 0.0005 < 0.3 GWA-62BRU Deep 6.5 0.6 72 0.361 2.1 3.8 959 36.0 573 160 146 < 0.1 353 < 1.4 0.0003 0.7 MW-20D Deep 6.5 0.2 442 < 0.025 1.5 1.1 3723 2.8 282 148 15 < 0.1 189 < 1.53 - 0.4 MW-23D Deep 6.9 0.8 < 50 0.026 0.8 0.7 1028 19.6 632 323 335 < 0.1 649 - - < 0.3 AS-02BR Bedrock 8.0 2.0 418 0.050 1.3 0.1 176 12.4 363 222 97 < 0.1 289 0.0016 < 0.3 AS-05BR Bedrock 6.9 0.7 < 50 0.928 1.8 < 0.1 99 6.1 9 47 7 < 0.1 79 - 0.0001 1.6 AS-06BRA Bedrock 6.6 0.3 < 50 0.044 0.8 0.1 84 2.8 26 60 4 < 0.1 96 0.955 - 0.8 AS-07BRB Bedrock 7.6 1.6 72 0.127 2.4 0.3 148 3.8 24 78 40 < 0.1 166 0.601 0.0040 0.8 AS-07BRL Bedrock 12.0 - < 50 - - - - - - - AS-08BR Bedrock 7.3 0.6 43 0.310 1.7 0.2 63 1.3 44 133 71 < 0.1 268 0.760 0.0044 1.0 AS-09BR Bedrock 8.1 6.5 < 50 0.057 1.8 0.2 202 4.8 40 49 7 < 0.1 124 < 0.464 0.0035 0.7 GWA-21BR Bedrock 7.2 < 0.1 133 < 0.025 < 0.5 0.4 3630 7.0 410 271 < 1 < 0.1 237 6.116 < 0.0005 < 0.3 GWA-21BRL Bedrock 7.2 0.4 213 < 0.025 < 0.5 0.2 3520 9.8 662 267 2 < 0.1 268 3.440 < 0.0002 0.3 GWA-33BR Bedrock 8.2 < 0.1 160 < 0.025 < 0.5 < 0.1 1304 31.1 334 204 79 < 0.1 282 - - < 0.3 GWA-54BRO Bedrock 6.6 0.9 92 0.042 4.1 0.2 965 13.9 54 165 109 < 0.1 310 0.878 0.0021 < 0.3 GWA-62BR Bedrock 9.2 - 307 - - - - - - - - - - - - - MW-02DA Bedrock 6.6 0.8 < 50 0.066 1.4 1.6 1609 21.7 801 140 21 < 0.1 143 - < 0.3 MW-20DR Bedrock 7.1 < 0.1 175 < 0.025 < 0.5 < 0.1 301 8.3 577 344 < 1 < 0.1 283 1.247 < 0.3 MW-23DR Bedrock 7.1 0.3 < 50 < 0.025 < 0.5 < 0.1 992 7.3 53 106 25 < 0.1 152 - < 0.3 MW 25DR Bedrock 6.4 0.6 < 50 0.196 0.6 1.0 53 2.1 10 51 2 < 0.1 70 0.3 Prepared by: TJG Checked by: TAW Notes: ' - Background threshold values were calculated using data from background groundwater samples collected June 2015 to September 2017. z - Background threshold values were calculated using data from background groundwater samples collected March 2011 to December 2018. 3 - Statistical mean, geomean, or median calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. Mean or geomean results were used based on the central tendency of the data set. For wells with datasets containing fewer than four valid results, the most recent valid sample data was used. Means were calculated for wells with four or more valid sample results. Sample results were excluded from calculations: 1) if turbidity >10 NTU (for COIs other than boron) 2) for unusable data (RO qualified) 3) if a result was non -detect at a reporting limit (RL) greater than the normal laboratory RL Bold text - Constituent concentration exceeds applicable comparison criteria. - bold highlighted concentration indicates value is greater than the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202 Standard and IMAC is April 1, 2013) - bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard - highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. < - concentration not detected at or above the adjusted reporting limit. - - value not available NE - not established mg/L - milligrams per liter pCi/L - picocuries per liter pg/L - micrograms per liter S.U. standard unit Page 4 of 4 TABLE 6-6 COI MANAGEMENT MATRIX ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC I Constituent Standards and Values - 02L Criterion - Lines of Evidence (LOE) - 02L Criterion Rationale - 02L Criterion Shall- 1 0.2 10.40 1.04 1 GWA-215 1 1 1 y One mean greater than 02L standard, GWA-21S exhibits fluctuating pH and highly variable arsenic concentrations igore 6-17 Arsenic 10 (Pg/Q <0.1 - 2 0.1- 6.35 i1mm 0 N Non -Conservative -tive Transition Zone 1 2 1.30 0.13 0 0 0 - No means gLe T beyond compliance boundary rester than 02L standard Bedrock 1 1 6.50 0.65 0 0 0 0 1 N No means preatir than 02L standard near or beyond compliance boundary Shallow 50 50 1596 2.28 3 AS-158, A5-2S, CU,ll 3 3 3 y Multiple means greater than 02L standardnear or beyond compliance "-na i adiscernabledl exhibits discernable plume at upstream dam and ash storage area (lboundary g6�',, Transition Zone 50 50 912 1.30 3 AS-7D, AS-8D, CLMW-3D 3 3 Multiple means greater than 02L near orb'c"piumcuh yand =tsdi;cemable plume at upstream d,ash =. and =s u,ofps=dsm,.ab Boron 700 (pg/L) <50 - 150 49.09 - 176.8 y 3 y Conservative Bedrock 50 50 418 0.60 0 0 0 No means greater than 02L standard, however boron background value is mapped as an indicator of potential ash 'i (;i=6_18 0 N Shallow 4 26 14.8 0.57 0 0 0 0 N No means greater than background value near or beyond compliance boundary Transition Zonal 2 1 2 42 042 0 1 0 0 No means greater than 02L standard near or beyond compliance boundary Chromium (Total) 10 (Pg/Q <0.5 - 26.2 1 - 26 N 0 1 N Non -Conservative Bedrock 4 1 3 4�1 O�41 0 0 0 N No means great r than 02L standard near or be and corn pi lance boundary Shallow 684 1 1700 6566 3.86 2 AS-71, GWA-33S 1 0 0 y g re r than Multiple means ate background value near or beyond a boundary, although isolated in nature compliance Transition Zone sis 1840 4310 2.34 2 AS -SD, MW-20D 2 0 round value near � MeuyTend6c alience boundary exhibits discemable plume near Multiple means greater than background M u upstream and downstream dams (Figune 6_20 ) Iron 300 (pg/L) �50 - 11000 56.3 - 37500 y 0 y Bedrock 6220 7680 3630 0.47 0 0 0 No means greater than background value near or beyond compliance boundary, exhibits discernable plume near upstream dam (F leu, 0 N Shallow 169 969 9650 9.96 4 AS-2s, AS -]I, CLMV/ 2, Cl_Ml 4 4 1 y Multiple means greater than background isplue near dambebnd1=ancee boundary and exhibits discernable plume at o.ns e.m d. , stream a ra "g. _ downstream AS -ID, AS-2D, AS-7D, � bD, AS-9D, GWA-62BRU, Multiple means greater than near or beyond compliance boundary and exhibits discernable plume at Manganese 50 (pg/L) Transition Zone 78 260 5 - 1000 7 - 9170 4911 19,11 1 Ml MW-23D y 2 0 y Variable nibackground,value -22b) downstream dam upstream dam, and ash storage area (Figure 6 Bedrock 89 13 01 9.00 6 AS-2BR, GWA-21BR, GWA-21BRL GWA-33BR, MW-2DA, MW-20DR 6 0 Multiple mean, greater than background value near or beyond compliance boundary and exhibits discernable plume at downstream dam, upstream dam, and ash storage area (Figure 6-22c) 0 y Shallow 1 4 15 1.26 3 AS-1SB, AS-2S, CLMW-3S 3 0 y multiple means greater than 02L standard near or beyond compliance boundary and exhibits discernable plume in ash storage are go Transition Zone 10 is 335 1.34 2 Cl_Ml MW-23D 2 2 Multiple means greater than 02L standard ear r 'anlod complianceace a boundaryand exhibits discernable plume at upstream den and es ..or. 62rvora Sulfate 25 mg �1 - 18.5 1.2- 510 y 0 y Conservative Bedrock 15 1 109 0.44 0 0 0 0 0 0 0 N y No means reater than 02L standard, sulfate oreat,rrthan back round value manced (Fi.ur. 6-240 _ greater Multiple means ter than 02L standard near or beyond compliance boundary and exhibits discernable plume in ash storage 2"a Shallow 75 57 594 1.19 2 AS-10, AS-2S Transition Zone 71 107 649 1.30 2 CUAW-3D, MW-23D 2 0 multiple means greater than 02L standard near or beyond Mpha!=dary and exhibits discernable plume in ash storage area III-. 625b) Total Dissolved Solids 500 (mg/') <25 - 10700 50 - 1200 y 0 y Conservative Bedrock 120 120 1 310 1 0.62 0 1 lines of Evidence 1 0 (LOE) 0 - IMAC Criterion N No means greater than 02L standard, TDS greater than background value mapped (Figure 6-25c) Rationale - IMAC Criterion Constituent Standards and Values IMAC Criterion Shallow 11 21 37.1 1.77 1 CLl 1 1 o y Only one mean greater than background value ,=do= compliance boundary, means greater than background value is_1, Transition Zone 5 5 30.8 6.16 2 AS-8C, AS-9D 2 1 multiple means greater than 11c==d 11 bllcirnadca=,in��ie boundary exhibits discernable plume at ash store ur. Cobalt I (pg/L) <0.1 - 22.9 0.2 - 88.85 y 0 y Variable Bedrock 1 2 1.6 0.80 0 0 4 0 2 0 6 N y n be, round value n e "' a ' d retert a _a eirori��" Multiple means greater 7ni��7ear_.ib_e a2boundary d exhibits discernable bounds rid mph: c at downstream dam Shallow 0.1 0.2 0.7 3.50 6 AS-158, A5-2S, AS-71, CLl CLMW-35, GWA-21S upstream dam, and ash storage area (Figure 6-26a) Thallium 0,2 ('g/L) <0.1 - 0.5 0.1-0.2 y Variable r Only one mean greater than IMAC near or beyond compliance arracebourridery constituent exhibit, discernable plume at prt Transition Zone 0.1 0.2 0.3 1.50 1 AS -ID 1 0 1 y earn dam nd ash _26 ups m a s ea F,l Bedrock 0.2 0.2 < 0.1 NA 0 0 0 0 0 0 N y No means � r n99%an, greater than ter "R IMAC near Multiple means greater than backg 777 orbeyondc."MML background background value iisolated irinituml�flgul 6-2 Shall.. I I 1 1 6.2 1 6.20 1 2 1 GWA-215, GWA-228 I Transition Zonal I 1 11 0.8 k 1 0.07 1 0 1 No means greater Than be n. r d iu. or beyond compliance boundary ckgmun value Vanadium 0.3 (Pg/Q <0.3 - 12.2 0.38-26 y 0 N Non -Conservative Non -Con Bedrock 1 0.4 1 1 1.6 1 1.60 1 2 1 1 I 0 0 y value, -5BR Two locations with means greater background va ., c.nstihtu�eimdnit=,tta, andiscern Is plume. Locations AS nd _ B, a t r itue t, l a=.roliv EL'o not hav nt Constituent Standardsand Values - Background Criterion Lines of Evidence CLOE) - Background Criterion Rationale - Background Criterion Q o o N No means greater than background value near or beyond compliance boundary Shallow 0.5 4 2.360 0.59 0 Transition Zone 0.2 0.6 0.444 0.74 0 a No means greater than background value near or beyond compliance boundary Chromium (Hex -lent) NE (Pg/L) <0.025 - 4.8 0.03 - 12 N a N Variable Bedrock 0.1 0.7 0.928 1.33 1 AS5BR 1 0 0 y Only one location me=ds=uned Constituenta�lue..notreigaerrt�hannslbackgmunil -.1be in ash pore water. IA n have nd of nc value. "t ' '=ig to btuel ese Shallow - 3 9.3 3.14 7 AS1SB, AS4S, AS-71, Cl-2, CLMl GWA-215, GWA-33S 5 0 0 y Multiple means greater than background value near or beyond compliance boundary and exhibits discernable plume in ash storage area (Figure 6-211 Transition Zone 12 36.0 3.00 4 AS-2D, GWA-33D, GWA-62BRU, MW-23D 4 4 Multiple means greater than background value near or beyond compliance boundary and exhibits discernable plume at upstream dam (Figure 6-21b) Lithium NE (pg/L) <0.5 - 13.4 2 - 95.39 y 0 y Conservative Bedrock 11 31.1 2.83 4 AS-2BR, Gl GWA-54BRO, Ml 4 3 Multiple means greater than background value near or beyond compliance boundary and exhibits discernable plume in ash re storage area (Figu6_2lit 0 y Shallow 37 34 204 6.00 9 AS-10, AS-2S, �S, A5-71, CLMW-2, Cil 6 5 0 y Multiple means greater than backgroundvaluenearorbeyond compliance boundary and exhibits discernable plume at GWA-225, GWA-335, MW-235 w stream dam upstream dam, m, and ash storage area (Figure 6-23a) AS-1D, AS-2D, AS-7D, AS-8D, CLMl GWA-21BRU, Cil GWA-33D, GWA47C, GWA Multiple means greater than background value near or beyond compliance boundary and exhibits discernable plume at c strontium NI (P11L) 6.3- 116 27 - 2272 y Non -Conservative Transition Zone 56 69 533 7.72 13 54D, GWA-62BRU, MMW-23D l 12 12 0 y stream dam, upstream dam, and ash storage area (Figure 6-23b) nstream down Bedrock 107 93 344 3.70 8 AS-2BR, AS-8BR, GWA-21BR, GWA-21BRL, GWA-33BR, GWA-54BRO, MW-2DA, MW-20DR 8 8 0 -1 Multiple means greater than background value near dar.belondd=argc�e ar.d exhibits discernable plume at upstre a store abm1unda downstream dam go Shallow 3 2 1 1 1.2 0.61 0 0 0 0 N No means greater than background value near or beyond compliance boundary Transition Zone 2 3 1.4 0.68 0 0 0 0 N re No means greater than background value near or beyond compliance boundary Total Radium NE (pCi/Q 0-3.46 1 - 35 N Variable Bedrock 3 3 6.1 2.04 2 GWA-21BR, GWA-21BRL 1 1 0 y Constituent greater thanvalue in two at'um: well =� not detected greater than comparative criteria I n no ase a a d sc a . no in 'low d _ ' n�� Shallow 0.0005 0.0005 1 0.0011 2.20 2 AS-15B, GWA-215 2 2 0 y nd 0 multiple means greater than background value neard,= cilgp.r1rarce boundary,) means greater thb'�Mlck� value so ate ig _27.) Transition Zone 0.0005 0.00059 <0.0005 N/A 0 0 0 an - No greater b round near an thany*n c il bounds Lvaluebev'lue -1 Uranium NE (pg/L) < .0005 0.0002 - 0.0167 Non -Conservative Bedrock 0.0005 0.00 5 0.0044 5 AS-26R, AS-7BRB, AS-SBR, AS-99R, GWA-54B 5 5 0 y ,or a2'p Multiple means greater than background ian un ry and exhibits discernable plume in ash t compliance beyond c; boundary store area (Figure 627b) Metals Reference CrIter- `Z' :�Pp e-l- ,,t . = "", C-i- Ill ren the Cm lil i-b- i. th, 2018 - Ul - tv, i or Ill. J d1ld backgrountl 11-111tl - are in 11 1hil column - were -111111d 11i's tlala from backgrountl urixii-1, samples colle .-r 1010 to clo-111 lals - --t- . bCrEiQ 1- 2 51 - me c mean was used for COI with --arbu., range 1ess than or 1 to one order of magnitude. Ge.rietft rie.. was used far COI with concentration range gire.t., than one order of magnitude. is th, ,, of - m- constituent --tin- di- by - comparative criterion. -ignirent of --tNe, -r-r-o-, or -ble beh-l., Is based an ge.ch-c.1 modeling results. reater Man le s than cl, - `, , csA pnih �Iw, Site rt IMAC-interim b ft maximum -ttrAi- ,91L "l per Ill 11- - milligrams per Ill 1A - - Applic.ble ,e Not -1 -d S U S. .1l d.m u y - y, N N. TABLE 6-7 SUMMARY TREND ANALYSIS RESULTS FOR MONITORING WELLS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC I(852) ®©� I (3)9)-� 1 (118D) 1(22s) 1 (744) �amo© I(293) �a000 I ©© 1 1(169D) ® 1(239) . I(420) ©®�r I (424) Imo©© I (359) ©©© Wen, Downgradlent of the Sour« Area Near or Beyond Compliance Boundary Well ID TOWI Boron Lithium Sulfate Di„od. Bona, Bedrock Flow Zone Cont. As-OSBR ND D D As-O6BRA ND s D s ccR-16D SWA-33BR MW-20DR D s S ND NT MW-218R ND s s NI MW-23DR ND s Mann-Kentlall trend analysis antl results prepared by Arcadls D.S. Inc. Prepared by: MAF Checked by: H Notes, 1. Summary of results and trends are presented for samples collected from 2008 - 2019. 2. Trend results are presented when at least four samples were available and frequency of detection was >50%. Statistically significant trends are reported at the 90 % confidence level. 3. Variability Index (VI) is calculated as the (maximum - minimum) / median concentration and is calculated using detected concentrations only. Values less than 1 indicate low variability in the dataset. 4. For pH, statistically significant, increasing trend with a maximum recent result (2018 - 2019) less than the lower end of the standard range or greater than the upper end of the standard range. Maximum detected result for 2018 and 2019 time period shown in parentheses. S. Wells that had insufficient samples collected (n<4) for all four cansitituents were removed from table. See designation 'NE'. ND = Greater than 50 percent of constituent concentrations were non -detect = Statistically significant, decreasing concentration trend = Stable. No significant trend and variability is low (VI < 1) = No significant trend and variability is high (VI > 1) = Statistically significant, increasing concentration trend. NE = Insufficient number of samples to evaluate trend (n < 4) TABLE 6-8 SEEP CORRECTIVE ACTION STRATEGY ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Regulatory Approximate Seep ID Program General Location Average Present Anticipated Seep Corrective Action Strategy Flow (cfs) S-04 NPDES Channel flow north of 0.05 This location is to be covered by the NPDES permit and ash storage area designated as Outfall #104. S-06 NPDES Channel flow north of toe of AAB 0.1 This location is to be covered by the NPDES permit and downstream dam designated as Outfall #106. As decanting continues, the portion of flow from the AAB to this seep location is expected to be reduced or eliminated. If seep S-07 SOC Northeast of AAB 0.001 S-7 sustains near its average flow rate after AAB decanting is downstream dam complete, it is expected that the COI concentrations are reduced. Under these circumstances, the current proposed action for this area is continued monitoring. Location is associated with the AAB upstream dam. Decanting has been effective in reducing visible standing water at the seep location. Further decanting and groundwater corrective Toe of AAB upstream action might cause the volume of water at the toe of the AAB S-14 SOC dam <0.001 upstream dam to reduce more or be eliminated. If the seep continues to have low flow conditions, and is not dispositioned after decanting is complete, phytoremediation technology could be implemented to capture and extract shallow groundwater to reduce or eliminate flow at this seep location. Location is associated with the AAB upstream dam. Decanting has been effective in reducing visible standing water at the seep location. Further decanting and groundwater corrective Toe of AAB upstream action might cause the volume of water at the toe of the AAB S-15 SOC dam <0.001 upstream dam to reduce more or be eliminated. If the seep continues to have low flow conditions, and is not dispositioned after decanting is complete, phytoremediation technology could be implemented to capture and extract shallow groundwater to reduce or eliminate flow at this seep location. Page 1 of 2 TABLE 6-8 SEEP CORRECTIVE ACTION STRATEGY ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Seep ID Regulatory Program General Location Approximate Average Present Flow (cfs) Anticipated Seep Corrective Action Strategy Location is associated with the AAB upstream dam. Decanting has been effective in reducing visible standing water at the seep location. Further decanting and groundwater corrective Toe of AAB upstream action might cause the volume of water at the toe of the AAB S-16 SOC dam <0.001 upstream dam to reduce more or be eliminated. If the seep continues to have low flow conditions, and is not dispositioned after decanting is complete, phytoremediation technology could be implemented to capture and extract shallow groundwater to reduce or eliminate flow at this seep location. Location is associated with the AAB upstream dam. Decanting has been effective in reducing visible standing water at the seep location. Further decanting and groundwater corrective Toe of AAB upstream action might cause the volume of water at the toe of the AAB S-21 SOC dam <0.001 upstream dam to reduce more or be eliminated. If the seep continues to have low flow conditions, and is not dispositioned after decanting is complete, phytoremediation technology could be implemented to capture and extract shallow groundwater to reduce or eliminate flow at this seep location. Notes• cfs- cubic feet per second NPDES - National Pollution Discharge Elimination System SOC - Special Order by Consent Prepared by: SAS Checked by: TJG Page 2 of 2 TABLE 6-9 WATER SUPPLY WELL ANALYTICAL RESULTS SUMMARY CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Turbidity Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Impacted by coal ash? Alternative Water Supplied? Water Type Reporting Units S.U. NTUs pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L pg/L mg/L pg/L mg/L pCi/L pg/L pg/L 15A NCAC 02L Standard 6.5 - 8.5 NE 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Values (Bedrock Flow Zone)' 5.4-7.4 NE 1 50 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Values (Bedrock Flow Zone)z 4.5 - 7.5 NE 1 50 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 Cliffside Background Dataset Range (Bedrock Flow Zone)z 4.8 - 7.6 NE <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Piedmont Background Value Range (Bedrock Flow Zone) 4.5-9.0 NE 1.0 - 6.0 49.1 - 50 0.03 - 8 2.8 - 11 0.2 - 18 147 - 7680 NE 7 - 1773 93 - 2272 2 - 130 0.1 - 0.2 120 - 675 1.0 - 6.0 0.0005 - 0.006 0.38 - 26 Sample ID Sample Date Analytical Results Cl Well 2 02/04/2015 7.5 <1 2.6 <25 <20 <5 <5 540 NA 7.6 26 13 NA 42 NA NA <5 No Yes -municipal water supply connection Calcium Bicarbonate Cl Well 2 05/27/2015 6.2 1.4 <0.5 <5 <0.6 3.2 <0.5 218 NA 13.1 50.1 9 NA 53 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate Cl Well 3 02/04/2015 6.7 <1 <1 <25 <20 <5 <5 210 NA 11 48 8.5 NA 60 NA NA <5 No Yes -municipal water supply connection Calcium Bicarbonate C10 02/04/2015 8.0 <1 1.6 <25 <20 <5 <5 650 NA 42 39 8.1 NA 54 NA NA <5 No Yes -municipal water supply connection Calcium Bicarbonate C10 05/27/2015 7.0 2.2 1.3 <5 <0.6 2.3 <0.5 <50 NA 49.6 38.2 7.6 NA 79 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C-1001: C2801 Riverfront 05/07/2014 NM NM <2 <50 NA <10 NA 78 NA NA 33 2 NA NA NA NA NA No Yes -municipal water supply connection Calcium Bicarbonate C-1001: C2801 Riverfront 10/18/2016 6.4 2.2 0.44 <25 <0.03 <0.5 0.18 289 NA 47.3 36.3 5.9 NA 62 NA NA <0.3 No Yes -municipal water supply connection ND C-1002: 2901 Fox Place 10/18/2016 6.2 6.4 0.19 <25 <0.03 <0.5 0.46 2970 NA 27.6 30.1 15.3 NA 63 NA NA <0.3 No Yes -municipal water supply connection ND C-1003 10/18/2016 7.6 <1 0.98 <25 <0.03 <0.5 <0.1 <50 NA 8.3 65.1 6.1 NA 108 NA NA <0.3 No Yes -municipal water supply connection Calcium Bicarbonate C-1004: C2800 Riverfront 05/07/2014 NM NM <2 <50 NA <10 NA <50 NA NA 20 NA NA NA NA NA NA No Yes -municipal water supply connection ND C-1004: C2800 Riverfront 10/18/2016 4.9 <1 <0.1 <25 0.63 1.2 <0.1 <50 NA 1.5 20.4 <2 NA 27 NA NA <0.3 No Yes -municipal water supply connection ND C-1005 SS 10/17/2016 6.8 1.1 0.3 <25 <0.03 <0.5 0.15 311 NA 23.5 41.1 2.9 NA 108 NA NA 0.64 No Yes -municipal water supply connection Calcium Bicarbonate C-1005 S2 10/17/2016 6.1 5.2 0.17 <25 0.32 0.79 <0.1 161 NA 5.4 20.5 <2 NA 36 NA NA No Yes -municipal water supply connection Calcium Bicarbonate C-1005 S4 10/17/2016 7.0 10.8 0.73 <25 0.17 <0.5 0.41 1670 NA 110 26.4 2.4 NA 43 NA NA No Yes -municipal water supply connection ND C-1005 SS 10/18/2016 6.9 4.1 <0.1 82 <0.15 <0.5 0.41 483 NA 56.9 26.4 <2 NA 34 NA NA 0.41 No Yes -municipal water supply connection Calcium Sulfate C-1005 Wl 10/17/2016 5.3 <1 <0.1 <25 0.13 <0.5 <0.1 <50 NA 1.5 15.6 2.3 NA 31 NA NA <0.3 No Yes -municipal water supply connection Calcium Bicarbonate C-1005 W2 10/17/2016 6.1 <1 0.56 <25 <0.03 <0.5 0.41 392 NA 59.1 54 5.8 NA 65 NA NA 1.1 No Yes -municipal water supply connection Calcium Bicarbonate C-1005 W3 10/17/2016 7.0 <1 <0.1 <25 <0.03 <0.5 <0.1 754 NA 34.9 54.5 5.9 NA 92 NA NA <0.3 No Yes -municipal water supply connection Calcium Bicarbonate C-1006: 2910 Fox Place 11/03/2016 7.3 <1 0.28 <25 0.026 <0.5 <0.1 81.6 NA 14.3 50.9 10.3 NA 104 NA NA <0.3 No Yes -municipal water supply connection Calcium Bicarbonate C-1007: 433 Dysart Place 11/03/2016 7.4 <1 0.23 <25 <0.12 <0.5 <0.1 455 NA 166 59.3 12.7 NA 98 NA NA <0.3 No Not eligible, outside 1/2 mile radius Calcium Bicarbonate C-1007: 433 Dysart Place 03/31/2017 7.4 1.2 0.25 <25 <0.025 0.88 <0.1 453 NA 173 61.5 12 <0.1 115 NA NA <0.3 No Not eligible, outside 1/2 mile radius Calcium Bicarbonate C-1008 11/03/2016 5.2 <1 <0.1 <25 <0.025 <0.5 0.65 <50 NA 12.3 18.4 <2 NA <25 NA NA <0.3 No Not eligible, outside 1/2 mile radius ND C105 Downriver 04/09/2014 5.4 1 <2 <50 NA <10 NA 320 NA NA NA 6.8 NA 99 NA NA NA No Yes -municipal water supply connection ND CS1 05/O1/2015 6.6 4.2 <0.5 <5 0.096 <0.5 <0.5 <50 NA 3 39.3 <2 NA <25 NA NA <1 No Yes -municipal water supply connection Calcium Sulfate c15 02/04/2015 8.0 2.3 1 <25 <20 <5 <5 2200 NA 230 140 11 NA 190 NA NA <5 No Yes -municipal water supply connection Calcium Bicarbonate C16 02/04/2015 6.6 4.9 <1 <25 <20 <5 <5 380 NA <5 30 2.6 NA 38 NA NA <5 No Yes -municipal water supply connection ND C17 02/04/2015 7.6 11 <25 20 3200 NA 630 81 1.2 NA 330 NA <5 No Yes -municipal water supply connection ND C19 02/04/2015 7.7 2.4 <1 <25 <20 <5 <5 240 NA <5 33 2.5 NA 25 NA NA <5 No Yes -municipal water supply connection ND C23 05/27/2015 6.9 1.1 <0.5 <5 0.83 1.5 <0.5 110 NA 3.1 15.7 <2 NA 44 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C24 05/27/2015 6.4 <1 <0.5 <5 <0.6 0.91 1.9 <50 NA 40.3 71.4 2.2 NA 106 NA NA <1 No Yes -municipal water supply connection ND C24 08/18/2015 6.3 1 <0.5 <50 0.44 <5 <0.5 <50 NA NA 60.8 2 NA 101 NA NA <1 No Yes -municipal water supply connection ND C24-1 05/27/2015 6.7 <1 <0.5 <5 0.63 0.88 <0.5 <50 NA 2.7 58.2 2.9 NA 90 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C25 05/27/2015 6.5 3.9 <0.5 <5 <0.6 14.1 <0.5 540 NA 3.6 28 5.6 NA 53 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C25 08/17/2015 6.4 1.2 <0.5 <50 0.11 <0.5 <0.5 <50 NA NA 28.2 4.8 NA 54 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C26 05/27/2015 6.1 <1 <0.5 5.6 <0.6 0.81 <0.5 188 NA 2.7 26 3.5 NA 41 NA NA <1 No Not eligible -outside 1/2 mile radius ND C26 08/17/2015 6.2 1.5 <0.5 <50 0.15 <0.5 <0.5 52.5 NA NA 27.1 3 NA 61 NA NA <1 No Not eligible -outside 1/2 mile radius ND C2968 Riverfront 04/09/2014 NM 5.6 NA <50 NA <10 NA 790 NA 33 NA 2 NA 101 NA NA NA No Yes -municipal water supply connection ND C3 02/04/2015 7.2 <1 <1 <25 <20 <5 <5 360 NA 20 51 4.8 NA 48 NA NA <5 No Yes -municipal water supply connection Calcium Bicarbonate C3 05/27/2015 6.5 <1 <0.5 5 <0.6 0.56 1.2 <50 NA 25.5 44 4.4 NA 36 NA NA <1 No Yes -municipal water supply connection Calcium Bicarbonate C4 Well 2 02/04/2015 7.0 1.2 <10 <25 <20 <50 <50 290 NA <50 <100 2.3 NA <10 NA NA <50 No Not eligible-business/church/school ND C4 Well 3 02/04/2015 7.0 210 20 6.7 <5 3200 NA 11 24 NA 160 NA No Not eligible-business/church/school ND C5 05/O1/2015 6.6 <1 <0.5 6.2 2.2 2.2 <0.5 <50 NA 1 20.2 2.3 NA 80 NA NA <1 No Yes -municipal water supply connection ND C7 05/O1/2015 7.6 <1 1.3 <5 <0.03 <0.5 <0.5 <50 NA 7.9 60.6 6.5 NA 94 NA NA <1 No Yes -municipal water supply connection ND C8 05/O1/2015 6.2 <1 <0.5 <5 0.74 0.86 0.72 57.3 NA 11 16 <2 NA 59 NA NA <1 No Yes -municipal water supply connection ND C8 Spring 05/O1/2015 5.6 34.8 <0.5 6.5 <0.03 2.2 1.6 <50 NA 16.8 14.9 5.9 NA 45 NA NA 3 No Yes -municipal water supply connection ND C9A O5/O1/2015 5.7 <1 <0.5 6.2 0.01 <0.5 <0.5 <50 NA 2.3 14.1 2.6 NA 32 NA NA <1 No Yes -municipal water supply connection ND C9B O5/O1/2015 7.1 <1 <0.5 1 <5 <0.03 <0.5 <0.5 1 749 NA 32.4 48.9 6.2 NA 97 NA NA 1 <1 No Yes -municipal water supply connection ND NNotg, - Background threshold values were calculated using data from background groundwater samples collected June 2015 to September 2017. mg/L - milligrams per liter - Background threshold values were calculated using data from background groundwater samples collected March 2011 to December 2018. pCi/L - picocuries per liter Turbidity of Sample z 10 NTUs pg/L - micrograms per liter Bold text - Constituent concentration exceeds applicable comparison criteria. S.U. standard unit * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. * - concentration not detected at or above the adjusted reporting limit. NA - not analyzed ND - water type of sample not determined due to charge balance >10 or 10 NM - not measured NE - not established NTU - Nephelometric Turbidity Unit epared by: TJG Checked by: SAS Page 1 of 1 TABLE 6-10 NPDES PERMIT LIMITS AND ANTICIPATED GROUNDWATER REMEDIATION PARAMETER LEVELS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC NPDES Outfalls Outfall 0021 Outfall 005 Maximum Detected Concentrations by Flow Zone Effluent Limitations and Monitoring Requirements Parameter Monthly Average Daily Maximum Monthly Average Daily Maximum Saprolite Transition Zone Bedrock Flow (MGD) NS 1 MGD NS NS NA NA NA Oil & Grease 15.0 mg/L 20.0 mg/L 15.0 mg/L 20.0 mg/L NA NA NA TSS 30.0 mg/L 50.0 mg/L 30.0 mg/L 50.0 mg/L 23.2 mg/L 14.7 mg/L 15.8 mg/L Total Chromium 0.2 mg/L 0.20 mg/L 0.2 mg/L 0.2 mg/L 0.008 mg/L 0.02 mg/L 0.02 mg/L Total Zinc 1.0 mg/L 1.0 mg/L 1.0 mg/L 1.0 mg/L 0.07 mg/L 0.04 mg/L 0.04 mg/L pH From 6.0 to 9.0 S.U. From 6.0 to 9.0 S.U. 4.1 - 5.8 S.U. 4.4 - 9.7 S.U. 6.4 - 8.3 S.U. Total Copper NA NA 251 Ng/L 272 Ng/L 3.6 Ng/L 5.3 Ng/L 4.9 Ng/L Chronic Toxicity NA NA Note 4 NA NA NA Total Iron NA NA 1.0 mg/L 1.0 mg/L 4.58 mg/L 9.37 mg/L 2.55 mg/L Total Residual Chlorine NA NA NS 28 Ng/L NA NA NA 5-day BOD; 20' C NA NA 30.0 mg/L 45.0 mg/L NA NA NA Fecal Coliform (geo. Mean) NA NA 200/100 mL 400/100 mL NA NA NA Temperature NA NA NS 100' F NA NA NA Notes: 1 - Effective beginning on the commencement of the dewatering operation and lasting until permit expiration. 2 - Downgradient groundwater monitoring wells in area of groundwater remediation; Q1 2018 through Q2 2019 data. 3 - Monitoring shall be per occurrence of chemical metal cleaning and sample from a representative discharge. 4 - Chronic Toxicity (Ceriodaphnia) P/F at 3.14%; March, June, September, and December. MGD - million gallons per day NS - not specified NA - not analyzed TSS - total suspended solids S.U. - standard units BOD - biological oxygen demand mg/L - milligrams per liter ug - micrograms per liter mL - milliliters Prepared by: VTV Checked by TJG Page 1 of 1 TABLE 6-11 FEATURE IRRIGATION SYSTEM SETBACK CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Feature Irrigation System Setback (feet) Spray Drip Private residence 400 100 Place of assembly owned by permittee 200 15 Surface waters 100 100 Property line 150 50 Prepared by: VTV Checked by: TJG Page 1 of 1 TABLE 6-12 REMEDIAL TECHNOLOGY SCREENING SUMMARY ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale COIs pose no unacceptable risk to Monitored Natural Attenuation human health or the environment under (MNA) Yes conservative exposure scenarios. MNA could be implemented in conjunction with source control measures. In -Situ Technologies Low Permeability Barriers (LPB) No Technically challenging and costly. Possible application to enhance capture Groundwater Flushing Yes of mobile COIs (e.g., boron) or to add amendments to immobilize certain COIs. Encapsulation No No area where COIs are concentrated. Permeable Reactive Barrier (PRB) No Boron is not amenable to treatment in a PRB. Groundwater Extraction Technologies Vertical Extraction Wells Yes Commonly used technology for groundwater extraction. Horizontal or Angular Extraction NO Modeling indicates that vertical Wells extraction wells are sufficient. Extraction Trenches No Modeling indicates that vertical extraction wells are sufficient. Hydraulic Fracturing No Not warranted based upon the limited extent of COIs in bedrock. Phytoremediation No Limited additional mass removal. Groundwater Treatment Technologies pH Adjustment Yes Retained for remedial alternatives that include groundwater extraction. Precipitation Yes Part of the treatment in the WWTP associated with Outfall 005. Ion Exchange No Expensive and not expected to be needed to meet discharge requirements. Membrane Filtration No Expensive and not expected to be needed to meet discharge requirements. Page 1 of 2 TABLE 6-12 REMEDIAL TECHNOLOGY SCREENING SUMMARY ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale Management of Extracted Groundwater Potential to discharge at Outfall 002 or NPDES Permitted Discharge Yes 005; must modify permit to include discharge of extracted groundwater Publicly Owned Treatment Works No Would require installation of (POTW) infrastructure; NPDES is a better option. Non -Discharge Permit/Infiltration NO Site soils have limited capacity to Gallery transmit water. Non -Discharge Permit/Land Will not be considered as long as disposal Application No via NPDES permitted outfall is a viable option. Beneficial Reuse Fire Protection No Limited application. Storage is problematic Non -Contact Cooling Water No Limited application. Dust Suppression and Truck Wash No Limited application. Prepared by:JEC Checked by: TJG Page 2 of 2 TABLE 6-13 REMEDIAL ALTERNATIVE 2 GROUNDWATER EXTRACTION AND CLEAN WATER INFILTRATION WELL SUMMARY ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Groundwater Extraction Well System Number of Wells Flow Zone Total Depth (ft bgs) 3 Saprolite 54 - 60 4 Saprolite/Transition Zone 92 - 112 16 Saprolite/Transition Zone/Bedrock 69 - 153 Total Extraction Well Count: 23 Groundwater extraction system flow and operation assumptions: Modeled groundwater extraction rate: 0.4 to 7.8 gpm per well; average 5.3 gpm per well. Estimated total system groundwater extraction rate: 122 gpm. Groundwater extraction wells operate to maintain water level near top of the submersible pump. Groundwater Infiltration Well S stem Number of Wells Flow Zone Total Depth (ft bgs) 21 Saprolite 30 - 79 17 Saprolite/Transition Zone 70 - 108 8 Saprolite/Transition Zone/Bedrock 87 - 134 1 Horizontal Well Saprolite 5 Total Infiltration Well Count: 47 Groundwater infiltration system flow and operation assumptions: Modeled groundwater extraction rate: 1.6 to 5.7 gpm per well; average 3 gpm per well. Modeled horizontal well groundwater infiltration rate: 44.7 gpm per well. Estimated total system groundwater infiltration rate: 184 gpm. Notes• ft bgs - feet below ground surface gpm - gallons per minute Prepared by: RAG Checked by: GTC Page 1 of 1 TABLE 6-14 ENVIRONMENTAL SUSTAINABILITY COMPARISONS FOR REMEDIATION ALTERNATIVES ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS LLC, MOORESBORO, NC Remedial Alternative Remedial Alternative 1 — Groundwater Remediation by MNA Remedial Alternative 2 — Groundwater Remediation by Extraction and Clean Water Infiltration Remedial Alternative 3 — Groundwater Remediation by Extraction and Clean Water Infiltration Wells and Galleries Emissions Units CO2 Emissions metric ton 2.07E+01 4.57E+03 3.31 E+04 Onsite NO, emissions metric ton 2.43E-02 1.26E+01 1.39E+00 Onsite SOX Emissions metric ton 2.48E-03 1.29E+00 1.42E-01 Onsite PM10 Emissions metric ton 2.19E-03 1.14E+00 1.25E-01 Total NOx emissions metric ton 4.25E-02 2.21E+01 6.81E+01 Total SOx Emissions metric ton 1.34E-02 8.84E+00 8.74E+01 Total PMjo Emissions metric ton 3.88E-03 5.85E+00 1.25E+01 Total Energy Used MMBTU 3.88E+03 7.50E+05 4.32E+06 Total Emissions metric ton 2.08E+01 4.62E+03 3.33E+04 Notes: COZ - Airborne emissions of carbon dioxide MMBTU - Million British Thermal Units NOx - Airborne emissions of nitrogen oxides (combination of nitrogen monoxide and nitrogen dioxide) SOx - Airborne emissions of sulfur oxides (combination of sulfur monoxide, sulfur dioxide, sulfur trioxide, and others) PMlo - Airborne emissions of particulate matter that is 10 micrometers or less in diameter Prepared by: GTC Checked by: SJB Page 1 of 1 TABLE 6-15 MODELED CLEAN WATER INFILTRATION WELL DETAILS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Easting Northing Approximate Ground Surface Elevation (feet) Pressure at Well Head (ft of Head Above Ground Surface) Well Depth (ft BGS) Targeted Flow Zones Total Simulated Flow (gpm) Vertical Clean Water Infiltration Wells IW-1 1177609.77 544864.72 776 10 129 Saprolite/Transition Zone/Bedrock 5.4 IW-2 1177669.80 544866.70 770 10 125 Saprolite/Transition Zone/Bedrock 5.4 IW-3 1177844.15 544863.18 745 10 103 Saprolite/Transition Zone/Bedrock 5.4 IW-4 1177961.75 544866.28 732 10 87 Saprolite/Transition Zone/Bedrock 5.4 IW-5 1178072.26 544864.91 747 10 98 Saprolite/Transition Zone/Bedrock 5.4 IW-6 1178183.46 544866.51 792 10 133 Saprolite/Transition Zone/Bedrock 5.4 IW-7 1178279.21 544863.41 799 10 128 Saprolite/Transition Zone/Bedrock 5.4 IW-8 1178368.50 544864.30 815 10 134 Saprolite/Transition Zone/Bedrock 5.7 IW-9 1178187.90 545042.20 758 10 101 Saprolite/Transition Zone 4.3 IW-10 1178125.00 545045.70 729 10 83 Saprolite/Transition Zone 4.3 IW-11 1178187.40 545163.00 736 10 86 Saprolite/Transition Zone 4.3 IW-12 1178243.25 545157.33 754 10 98 Saprolite/Transition Zone 4.3 IW-13 1178188.54 545270.10 721 10 65 Saprolite/Transition Zone 4.3 IW-14 1178240.34 545272.30 734 10 75 Saprolite/Transition Zone 4.3 IW-15 1177802.60 545097.50 730 10 70 Saprolite 1.9 IW-16 1177849.10 545097.50 720 10 61 Saprolite 1.9 IW-17 1177782.00 545044.50 744 10 79 Saprolite 1.9 IW-18 1177850.40 545040.60 731 10 65 Saprolite 1.9 IW-19 1177785.10 544939.30 750 10 78 Saprolite 1.9 IW-20 1177844.90 544938.30 739 10 66 Saprolite 1.9 IW-21 1178237.57 545099.15 759 10 60 Saprolite 1.9 IW-22 1178180.00 545242.80 725 10 33 Saprolite 1.6 IW-23 1178233.30 545244.60 734 10 37 Saprolite 1.6 IW-24 1178135.60 545185.10 721 10 34 Saprolite 1.6 IW-25 1178186.20 545187.80 733 10 39 Saprolite 1.6 IW-26 1178239.50 545187.80 746 10 44 Saprolite 1.6 IW-27 1178134.70 545130.00 726 10 37 Saprolite 1.6 IW-28 1178188.00 545132.70 740 10 43 Saprolite 1.6 IW-29 1178232.40 545127.40 753 10 49 Saprolite 1.6 IW-30 1178142.70 545076.80 737 10 43 Saprolite 1.6 IW-31 1178188.00 545075.90 752 10 50 Saprolite 1.6 IW-32 1178236.00 545072.30 766 10 56 Saprolite 1.6 IW-33 1177845.50 545126.88 719 10 70 Saprolite/Transition Zone 3.1 IW-34 1177776.10 545370.60 714 10 79 Saprolite/Transition Zone 3.1 IW-35 1177733.70 545332.40 728 10 91 Saprolite/Transition Zone 3.1 IW-36 1177715.30 545299.80 740 10 99 Saprolite/Transition Zone 3.1 IW-37 1177677.10 545270.10 745 10 103 Saprolite/Transition Zone 3.1 IW-38 1177664.40 545244.70 753 10 108 Saprolite/Transition Zone 3.1 IW-39 1177653.10 545192.30 757 10 107 Saprolite/Transition Zone 3.1 IW-40 1177603.60 545130.10 760 10 104 Saprolite/Transition Zone 3.1 IW-41 1177565.40 545074.90 764 10 102 Saprolite/Transition Zone 3.1 IW-42 1177798.80 545401.10 702 10 70 Saprolite/Transition Zone 3.1 IW-43 1177832.60 545447.30 696 10 66 Saprolite/Transition Zone 3.1 IW-44 1178182.70 545300.50 721 10 30 Saprolite 1.6 IW-45 1178237.70 1 545300.50 729 10 35 Saprolite 1.6 IW-46 1 1178136.501 545242.801 715 10 30 Saprolite 1.6 Horizontal Clean Water Infiltration Wells HW-1 NA NA 752-765 1 10 1 10-15 1 Saprolite 44.7 Notes: All depths are approximated and may change depending on site conditions. Flowrates are approximate and may change depending on site conditions. DTW - depth to water ft - feet ft BGS - feet below ground surface gpm - gallons per minute NA - Not applicable Prepared by: GTC Checked by: RAG Page 1 of 1 TABLE 6-16 MODELED GROUNDWATER EXTRACTION WELL DETAILS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Easting Northing Approximate Ground Surface Elevation (feet) OperationalTotal DTW Maintained In Well (ft BGS) Well Depth (ft BGS) Targeted Flow Zones Simulated Flow (gpm) Vertical Extraction Wells EX-1 1177675.17 544940.59 766 25 127 Saprolite/Transition Zone/Bedrock 5.6 EX-2 1177792.42 544977.73 747 15 115 Saprolite/Transition Zone/Bedrock 5.6 EX-3 1177908.52 544976.93 725 5 95 Saprolite/Transition Zone/Bedrock 5.6 EX-4 1178026.12 544980.03 726 5 91 Saprolite/Transition Zone/Bedrock 5.6 EX-5 1178136.63 544978.66 749 18 105 Saprolite/Transition Zone/Bedrock 5.6 EX-6 1178247.83 544980.26 780 39 126 Saprolite/Transition Zone/Bedrock 5.6 EX-7 1178343.59 544977.16 793 43 133 Saprolite/Transition Zone/Bedrock 5.6 EX-8 1178432.87 544978.05 819 69 153 Saprolite/Transition Zone/Bedrock 5.6 EX-9 1178135.50 545099.80 731 15 97 Saprolite/Transition Zone/Bedrock 5.6 EX-10 1178188.50 545104.30 748 27 109 Saprolite/Transition Zone/Bedrock 5.6 EX-11 1178138.90 545219.30 718 15 83 Saprolite/Transition Zone/Bedrock 5.6 EX-12 1178182.90 545215.90 728 18 89 Saprolite/Transition Zone/Bedrock 5.6 EX-13 1178244.90 545217.10 746 26 102 Saprolite/Transition Zone/Bedrock 5.6 EX-14 1178129.90 545332.00 710 13 69 Saprolite/Transition Zone/Bedrock 5.6 EX-15 1178185.10 545329.80 716 15 70 Saprolite/Transition Zone/Bedrock 5.6 EX-16 1178243.70 545328.70 730 20 83 Saprolite/Transition Zone/Bedrock 5.6 EX-17 1177798.90 545070.60 733 13 97 Saprolite/Transition Zone 7.8 EX-18 1177857.40 545158.40 718 12 92 Saprolite/Transition Zone 7.8 EX-19 1177690.74 544972.35 758 18 112 Saprolite/Transition Zone 7.8 EX-20 1177750.80 545007.50 755 24 109 Saprolite/Transition Zone 7.8 EX-21 1177846.70 545520.40 682 12 54 Saprolite 0.4 EX-22 1177788.80 545520.40 685 14 60 Saprolite 0.4 EX-23 1 1177729.90 1 545521.301 683 1 14 1 58 1 Saprolite 0.4 Notes: All depths are approximated and may change depending on site conditions. Flowrates are approximate and may change depending on site conditions. DTW - depth to water ft - feet ft BGS - feet below ground surface gpm - gallons per minute NA - Not applicable Prepared by: GTC Checked by: RAG Page 1 of 1 V C d 3 d L U. ,13 M rn a� 0 E R R IL 0+ C_ a E M U) i TABLE 6-17 EFFECTIVENESS MONITORING PLAN ELEMENTS ACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Effectiveness Monitoring Plan (EMP) Implemented 30 days after CAP Approval EMP Groundwater Well Monitoring Network (background, downgradient of source areas) Performance Monitoring Network AS-2S PMW-1BR PMW-4D AS-2D PMW-2S PMW-4BR AS-2BR PMW-2D PMW-5S CCR-7S PMW-2BR PMW-5D CCR-7D PMW-3S PMW-5BR CCR-7BR* PMW-3D PMW-6S PMW-1S PMW-3BR PMW-6D PMW-1D PMW-4S PMW-6BR Continued Monitoring Network GWA-20S GWA-28BR GWA-59BR GWA-20D GWA-33S GWA-62BRU GWA-20BR GWA-33D GWA-62BR GWA-21S GWA-33BR MW-11S GWA-21BRU GWA-43S MW-11DA GWA-21BR GWA-43D MW-11BRO GWA-21BRL GWA-43BR* MW-20D GWA-22S GWA-57S MW-20DR GWA-22BRU GWA-57BRU MW-23S GWA-22BR* GWA-57BR MW-23D GWA-28S GWA-59D MW-23DR GWA-28BRU Background Monitoring Wells' BG-1S GWA-24D MW-22DR BG-1D GWA-24BR MW-22BR GWA-24S GWA-25S MW-24DR EMP Groundwater Quality3, 4 (Semi -Annual Sampling Frequency) Alkalinity Iron Z Stro n ti u mZ Aluminum Lithiumz Sulfate 2 ArseniC2 Magnesium ThalliUM2 Bicarbonate Alkalinity Manganese Total Dissolved Solidsz Boron Nitrate + Nitrite Total Organic Carbon Calcium Potassium Total UraniuM2 Cobalt2 Sodium VanadiumZ Ferrous Iron Post -Closure Monitoring Plan (PCMP) Implemented after completion of ash basin closure activities PCMP Groundwater Well Monitoring Network (background, downgradient of source areas) A PCMP will be implemented at the Site in accordance with G.S. 130A-309.214(a)(4)k.2 after completion of ash basin closure activities. I PCMP Groundwater Quality I (Sampling frequency to be determined) Parameters and sampling frequency to be included in the PCMP in accordance with G.S. 130A-309.214(a)(4)k.2 when submitted. I CMP and PCMP Groundwater Field Parameters I Water Level Specific Conductivity Temperature pH Oxidation Reduction Potential Dissolved Oxygen EMP Review Annual Effectiveness Monitoring Evaluation and Reporting 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation of compliance with applicable Standards 4) Evaluation of system performance and effectiveness 4) Recommend plan adjustments, if applicable, to optimize the remedial action 5-Year Performance Review Reporting 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Re-evaluate effectiveness of technology 4) Verify modeling results, update model if needed 5) Modify corrective action approach, as needed, to achieve compliance goal established EMP Duration 30 days after CAP approval, the EMP will be implemented at the Site and will continue until there is a total of three years of data confirming COIs are below applicable Standards at or beyond the compliance boundary, at which time a request for completion of active remediation will be filed with NCDEQ. If applicable standards are not met, the EMP will continue and transition to post -closure monitoring if necessary. PCMP Review Annual Evaluation and Reporting_ 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation 02L compliance 4) Recommend plan adjustments, if applicable At a frequency no greater than 5 years: 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Verify model results, update if needed PCMP Duration After ash basin closure and following ash basin closure certification, a PCMP will be implemented at the Site for a minimum of 30 years in accordance with G. S. 130A-309.214(4)(k)(2). Early termination: If groundwater monitoring results are below applicable Standards at the compliance boundary for three years, Duke Energy will request completion of corrective action in accordance with G.S. 130A- 309.214(a)(3)b. If groundwater monitoring results are above applicable Standards, the PCMP will continue. Prepared by: TJG Checked by: SAS ' Approved background groundwater monitoring locations 2 Corrective action COIs to monitor plume stability and physical attenuation either from active remedy or natural dilution/dispersion ' The number of monitoring wells and parameters may be adjusted based on additional data and the effects of corrective action. ° Groundwater standards may be modified over time in accordance with 02L .0106(k) * Proposed new well Proposed performance monitoring well clusters PMW-1 through PMW-6 are considered replacement wells for well clusters AS-1, AS-7, AS-8, AS-9, CLMW-3, and VW-2, which will be abandoned prior to excavation of the ash storage area. The location of the replacement well clusters has been optimized for performance monitoring. Italicized parameters - parameters for general water quality to evaluate monitoring data quality Wells indicated in red will have geochemical sondes placed to monitor geochemical conditions Page 1 of 1 Corrective Action Plan Update December 2019 Cliffside Steam Station Source Area 2 (Former Units 1-4 Ash Basin) SynTerra TABLE 6-18 BORON CONCENTRATIONS IN GROUNDWATER BELOW SOURCE AREA FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Boron Boron Well Beneath Number Time Period Concentration Concentration Ash of Sam Sample P of Record Range in Range in (Flow Zone) Events Groundwater Overlying Pore (Ng/L) Water(Ng/L) IB-1D 5 06/2015 - 04/2016 <501 165 - 241 (Deep) (-5' saturated ash) IB-2AL (Shallow - 2 06/2015 - 09/2015 480 - 490 Alluvial) 220 - 240 IB-2BRU (Deep) 2 06/2015 - 09/2015 <501 (-12' saturated ash) IB-2I 2 06/2015 - 09/2015 99 (Shallow) IB-4BR (Bedrock) 3 06/2015 - 09/2015 52 - 57 320 - 390 IB-4D (-13' saturated ash) 2 06/2015 - 09/2015 <501 (Deep) Prepared by: TJG Checked by: SAS Notes: < - concentration not detected at or above the adjusted reporting limit 1 - Concentrations have not been detected at or above the adjusted reporting limit across all sampling events Page 1 of 1 TABLE 6-19 SUMMARY OF UNSATURATED SOIL ANALYTICAL RESULTS FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameters pH Arsenic Boron Cobalt Iron Manganese Strontium Sulfate Thallium Vanadium Reporting Units S.U. mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater NE 5.8 45 0.9 150 65 1,500 1,438 0.28 350 Background Threshold Values 4.0-6.8 7.8 31 48 74,362 672 9.9 13 1.1 161 Sample ID Sample Collection Date Analytical Results Background BGSB-MW-30 (6-7) 10/17/2017 5.2 4.3 B <9.6 M 6.2 73,000 M 160 16 <13 0.39 180 B BGSB-MW-30 (14-15) 10/17/2017 5.2 2.7 B <5.9 30 49,000 190 0.89 j <13 0.32 130 B BGSB-MW-30 (24-25) 10/17/2017 5.6 0.73 B <15 12 38,000 390 <6.2 <13 M 0.41 83 B BGSB-MW-32 (2-3) 10/19/2017 4.8 12 <14 2.4 44,000 B 40 6.9 35 0.31 89 BGSB-MW-32 (14-15) 10/19/2017 4.4 6.4 <4.8 2.6 40,000 B 130 0.6 j <12 0.15 71 MW-30D (3.5 - 5.5) 02/23/2015 5.9 j 3.2 j <3.9 7.3 48,500 145 1.1 <394 <1.6 97.8 MW-30D (8.5 - 10) 02/23/2015 6.0 j 2.4 j <4.1 3.3 j 27,300 89 1.6 <396 <4.1 70.3 MW-30D (18.5 - 20) 02/23/2015 5.0 j 3.5 j <4.7 2.4 j 60,600 215 <0.94 <488 <1.9 125 MW-30D (28.5 - 30) 02/23/2015 6.1 j 3.6 j 27.3 j 36.1 38,700 979 <7.7 <380 1 j 93.8 MW-32D (3.5 - 5) 02/23/2015 5.2 j 3.8 <30.1 5.7 48,700 148 1.4 204 j <1.2 96.7 MW-32D (8.5 - 10) 02/25/2015 6 j 1.9 j <30.6 6.7 44,800 107 2 <309 <1.2 74.5 MW-32D (18.5 - 20) 02/25/2015 5.9 j 1.7 <3.3 3.2 2,760 62 13.3 1 <321 <1.3 3 MW-32S (22.5 - 24) 03/12/2015 6.3 j 7.9 <38.9 33.8 46,400 910 1.4 j+ <387 <3.9 90.1 Beyond Ash Basin Waste Boundary GWA-10D (13.5 - 15) 04/21/2015 7.6 j 10.3 11.1 j 5.4 j+ 11,100 208 4.2 228 j <6.8 20.2 GWA-12BRU (20 - 23.5) 03/31/2015 6.5 j <2.7 6.8 j 3 7,640 152 <2.7 <266 <2.7 5 GWA-13BR (13 - 14.5) 03/04/2015 5.9 j 2.2 24.8 j 22.9 34,700 624 <7.7 <377 0.85 j 73.7 GWA-29D (16.2 - 16.2) 05/07/2015 6.6 j <5 <12.4 9.2 20,000 174 <2.5 <258 <5 17.3 Prepared by: TJG Checked by: VJH Notes: 0 . Bold highlighted concentration indicates exceedance of the Inactive Hazardous Sites Branch PSRG Table (May 2019) for Protection of Groundwater or the Background Threshold Value (BTV), whichever is higher. < - Concentration not detected at or above the adjusted reporting limit. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 1OX the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j+ - Estimated concentration, biased high. M - Matrix spike / matrix spike dup failure. mg/kg - milligrams per kilogram NE - not established PSRG - preliminary soil remediation goals S.U. - standard units Page 1 of 1 TABLE 6-20 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L mg/L Ng/L mg/L pCi/L Ng/L Ng/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 - 6.1 1 50 0.5 4 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone )2 4.0 - 6.0 0.2 50 4 26 1 21 1700 3 969 34 1 4 0.2 57 2 0.0005 1 2019 Background Dataset Range (Shallow Flow Zone )2 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7- 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 10700 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 - 6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone )2 4.9 - 7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range (Deep Flow Zone )2 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4 - 7.4 1 50 0.1 4 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone )2 4.5 - 7.51 1 50 1 0.7 1 3 1 2 1 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range (Bedrock Flow Zone )2 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID Flow Zone Mean, Geomean, or Median Result3 Background Locations GWA-30S Shallow 5.7 0.1 < 50 0.041 1.3 5.0 264 1.1 269 24 < 1 0.2 43 - - < 0.3 MW-30S Shallow 5.3 0.1 < 50 3.12 3.0 0.4 159 1.2 8 10 < 1 < 0.1 33 0.490 < 0.0005 < 0.3 MW-32S Shallow 5.0 0.1 < 50 0.177 0.6 1.1 73 2.5 37 27 < 1 0.1 59 1.107 < 0.0005 < 0.3 MW-30D Deep 8.3 1.6 < 50 0.076 < 0.5 < 0.1 53 11.1 8 61 16 < 0.1 107 1.333 0.0003 10.0 MW-30DA Deep 6.7 0.2 < 50 < 0.025 0.6 0.8 241 10.2 219 65 10 < 0.1 116 0.536 < 0.0005 0.3 MW-32D Deep 5.9 0.1 < 50 0.034 < 0.5 1.8 < 50 2.8 11 40 7 < 0.1 73 0.533 < 0.0005 < 0.3 GWA-30BR Bedrock 6.3 0.2 < 50 < 0.025 0.7 < 0.1 7198 3.6 70 52 14 < 0.1 90 - - 0.2 MW-32BR Bedrock 7.0 0.1 < 50 < 0.025 0.8 < 0.1 5305 6.1 33 57 16 < 0.1 103 0.386 < 0.0005 < 0.3 Between Waste Boundary and Compliance Boundary Upgradient of the Ash Basin GWA-14S Shallow 6.0 0.2 63 1.300 2.1 0.4 392 19 95 85 0.1 217 - 1.1 GWA-14D Deep 5.9 0.1 101 0.986 1.3 0.2 79 0.7 6 228 186 < 0.1 413 0.5 GWA-13BR Bedrock 6.5 0.2 84 < 0.025 1.0 < 0.1 5674 17.7 249 157 91 < 0.1 321 0.4 GWA-14BR Bedrock 8.5 1.3 < 50 0.162 1.4 0.2 227 17.9 52 123 54 1 < 0.1 184 - 1.4 Downgradient of the Ash Basin GWA-10S Shallow 5.2 0.6 97 0.043 < 0.5 5.9 182 5.0 1038 227 131 0.2 259 1.347 < 0.3 GWA-12S Shallow 5.6 0.1 < 50 0.042 1.0 0.2 117 0.6 6 18 13 < 0.1 86 - < 0.3 GWA-10D Deep 5.9 < 0.1 < 50 0.780 1.1 3.1 < 50 6.2 174 139 24 < 0.1 125 < 0.573 0.4 GWA-12BRU Deep 6.0 0.1 < 50 < 0.025 < 0.5 2.3 503 2.7 43 49 9 < 0.1 101 - < 0.3 Near Compliance Boundary Downgradient of the Ash Basin CCR-IB-01S Shallow 5.8 0.2 151 0.028 0.6 2.8 858 < 0.5 1706 395 79 < 0.1 196 < 1.14 < 0.3 CCR-IB-03S Shallow 6.3 109 270 0.027 0.9 16.6 4740 15.7 2068 898 200 0.1 471 < 1.09 < 0.3 GWA-11S Shallow 5.9 1.2 398 < 0.025 0.6 1.6 621 2.6 1970 554 105 < 0.1 299 0.456 < 0.0005 1.2 IB-06S Shallow 5.5 0.1 590 0.028 1.5 18.3 606 3.3 7333 369 258 0.1 457 1.620 < 0.0005 < 0.3 IB-07S Shallow 5.7 12.6 268 < 0.025 1.4 10.5 1613 10.0 1627 305 109 0.2 307 1.240 < 0.0005 0.5 CCR-IB-01D Deep 5.8 0.2 < 50 0.027 0.7 0.3 3328 3.8 110 60 14 0.1 97 < 0.711 - < 0.3 CCR-IB-03D Deep 9.6 0.8 65 2.543 2.5 < 0.1 < 50 28.1 < 5 229 86 < 0.1 321 - - 1.7 GWA-11BRU Deep 6.5 0.3 350 0.120 0.7 0.7 421 16.2 740 285 103 < 0.1 319 2.947 < 0.0005 0.6 GWA-29D Deep 5.7 < 0.1 < 50 0.167 0.9 0.3 150 1.6 9 35 8 < 0.1 66 1.368 < 0.0005 < 0.3 GWA-32D Deep 6.0 0.1 < 50 0.097 < 0.5 0.1 124 0.6 10 11 2 < 0.1 27 - 0.0002 < 0.3 IB-06D Deep 7.0 0.1 128 < 0.025 1.6 0.1 2090 12.2 289 209 51 < 0.1 253 4.930 0.0001 < 0.3 IB-07D Deep 6.7 0.7 < 50 0.028 2.0 1.3 350 5.7 196 126 30 < 0.1 221 - 0.0002 0.5 CCR-IB-03BR Bedrock 6.6 0.4 < 50 < 0.025 0.7 4.6 25750 21.6 9570 813 1395 < 0.1 2298 37.833 0.0002 0.4 GWA-11BR Bedrock 7.5 1.3 207 < 0.025 < 0.5 0.8 46 7.2 84 299 67 1 < 0.1 322 1.980 0.0016 0.9 GWA-11BRL Bedrock 8.3 < 50 - - GWA-29BRA Bedrock 7.7 1.8 < 50 0.067 0.7 0.2 1 153 0.4 29 213 11 1 < 0.1 146 1.2 Notes: ' - Background threshold values were calculated using data from background groundwater samples collected June 2015 to September 2017. NE - not established z - Background threshold values were calculated using data from background groundwater samples collected March 2011 to December 2018. mg/L - milligrams per liter 3 - Statistical mean, geomean, or median calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. pCi/L - picocuries per liter Mean or geomean results were used based on the central tendency of the data set. pg/L - micrograms per liter For wells with datasets containing fewer than four valid results, the most recent valid sample data was used. S.U. standard unit Means were calculated for wells with four or more valid sample results. Sample results were excluded from calculations: 1) if turbidity >10 NTU (for COIs other than boron) 2) for unusable data (RO qualified) 3) if a result was non -detect at a reporting limit (RL) greater than the normal laboratory RL Bold text - Constituent concentration exceeds applicable comparison criteria. - bold highlighted concentration indicates value is greater than the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202 Standard and IMAC is April 1, 2013) bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard - highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. < - concentration not detected at or above the adjusted reporting limit. - - value not available Prepared by: TJG Checked by: TAW Page 1 of 1 TABLE 6-21 COI MANAGEMENT MATRIX FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Constituent Standards and Values - 02L Criterion Lines of Evidence (LOE) - 02L Criterion Ratlonale - 02L Criterion Arsenic 30 (pg/L) Shallow 1 0.2 <0.1 - 2 0A - 6.35 108.90 10.89 2 CCR-IB-35, 1EI V 2 2 2 y Non -Conservative Multiple means greater than 02L standard near Compliance bountlary and exhibits discernable plume (Figure 6-46) T2nsition Zone 1 2 0.80 0.08 0 - 0 0 0 N No means greater than 02L standard near compliance boundary Bedrock 1 1 1.80 0.18 0 - 0 0 0 N No means greater than 02L standard near compliance boundary Boron 700 (pg/L) Shallow 50 50 <50 - 150 49.09 - 176.8 590 0.84 0 - V 0 0 0 N Conservative No means greater than 02L standard, however boron greater than background value is mapped as an indicator of potential ash basin influence (Figure 6-47a T2nsition Zone 50 50 350 0.50 0 - 0 0 0 N No means greater than 02L standard, however boron greater than background value is mapped as an indicator of potential ash basin influence Fi ure "7b Bedrock 50 50 207 0.30 0 - 0 0 0 IN means greater than 02L standard, however boron greater than background value is mapped as an indicator of potential ash basin influence Fi ure 6-470 chromium (Total) 10 (pg/L) Shallow 4 26 <0.5 - 26.2 1 - 26 1.5 0.06 0 - N 0 0 0 N Non -Conservative No means greater than background value near compliance bountlary T2nsition Zone 2 2 2.5 0.25 0 - 0 0 0 N No means greater than 02L standard near compliance boundary Bedrock 4 3 0.7 0.07 0 - 0 0 0 N No means greater than 02L standard near compliance boundary iron 300 (pg/L) Shallow 684 1700 SO- 11000 56.3 - 37500 4740 2.79 1 CCR-IB-3S V 0 0 0 V Variable One mean greater than background value near compliance boundary, isolated occurrence (Figure "9a) T2nsition Zone 515 1840 3328 1.81 2 CCR-IB-SD, I13-613 1 0 0 V Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure "9b) Bedrock 6220 7680 25750 3.35 1 CCR-IB-3BR 1 1 0 V One mean greater than background value near compliance boundary, isolated occurrence (Figure 6-49c) Manganese 50 (pg/L) Shallow 169 969 5 - 1000 7 - 9170 7333 7.57 5 CCR-IB-SS, CCR-IB-3S, GWA-I1S, IB-6S, IB-7S V 5 5 0 V Variable Multiple means greater than background value near compliance boundary and exhibits discernable plume (119ure 5-51a) T2nsition Zone 78 260 740 2.85 2 GWA-11BRU, I13-61) 1 0 0 V Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure 6-51b) Bedrock 89 113 9570 107.53 1 CCR-IB-3BR 1 1 1 V One mean greater than background value near compliance boundary, isolated occurrence (Figure 6-51c) Sulfate 250 (mg/1) Shallow 1 4 <1 - 18.5 1.2 - 510 258 1.03 1 IB-6S V 1 1 0 V Conservative One mean greater than 02L standard ,or compliance boundary, isolated occurrence (Figure 6-53a) T2nsition Zone le 15 103 0.41 0 - 0 0 0 N NO means greater than 02L standard near compliance boundary Bedrock 15 17 1395 5.58 1 CCR-IB-3BR 1 1 1 V One mean greater than 02L standard near compliance boundary, isolated occurrence (Figure 6-53b) Total Dissolved solids 500 (mg/I) Shallow 75 57 <25 - 10700 50 - 1200 471 0.94 0 - y 0 0 0 N Conservative No means greater than 02L standard near compliance boundary T2nsition Zone 71 107 121 0.64 0 - 0 0 0 N NO means greater than 02L standard near compliance boundary Bedrock 120 120 2298 4.60 1 CCR-IB-3BR 1 0 1 y One ,an greater than 02L standard near compliance boundary, isolated occurrence (Figure 6-54) Constituent Standards and Values - IMAC Criterion Lines Of Evidence (LOE) - IMAC Criterion Rationale - IMAC Criterion Cobalt 1 (pg/L) Shallow 11 21 <0.1 - 22.9 0.2 - 88.85 13.3 0.87 0 - y 0 0 0 N Variable No means greater than background value near compliance bountlary Transition Zone 5 5 1.3 0.26 0 - 0 0 0 N No means greater than background value near compliance boundary Bedrock 1 2 4.6 2.30 1 CCR-IB-3BR 1 0 0 V One mean greater than background value near compliance boundary, isolated occurrence (Figure 6-46) Thallium 0.2 (pg/L) Shallow 0.1 0.2 <0.1 - 0.5 0.1 - 0.2 0.2 1.00 0 - y 0 0 0 N Variable No means greater than IMAC near compliance boundary Transition Zone 0.1 0.2 0.1 0.50 0 - 0 0 0 N No means greater than IMAC near compliance boundary Bedrock 0.2 0.2 < 0A NA 0 - 0 0 0 N No means greater than IMAC near compliance boundary Vanadium 0.3 (pq/L) Shallow 1 1 <0.3 - 12.2 0.38 1.2 1.20 1 GWA-115 y 0 0 0 V Non -Conservative One mean greater than background value near compliance boundary, isolated occurrence (Figure 6-56a) Transition Zone 1 11 1.7 0.15 0 - 0 0 0 N No means greater than background value near compliance boundary Bedrock 0.4 1 1.2 1.20 1 GWA-29BRA 0 0 0 V One mean greater than background value near <omphance boundary, isolated occurrence (Figure 6-56b) Constituent Standards and Values - Background Criterion Lines of Evidence (LOE) - Background Criterion Rationale - Background Criterion Chromium (Hexavalent) NE (pg/L) Shallow 0.5 4 <0.025 - aS 0.03 - 12 0.028 0.01 0 - N 0 0 0 N Variable No means greater than background value near compliance boundary Transition Zone 0.2 0.6 2.543 4.24 1 CCR-IB-3D 1 0 0 V One mean exceeds comparstive criteria, constituent not present greater than comparative criteria in ash pore water, probably not related to ash basin Bedrock 0.1 0.7 0.067 0.10 0 - 0 0 0 N No means greater than background value near compliance boundary Lithium NE (pg/L) Shallow - 3 <0.5 - 13.4 2 - 95.39 15.7 5.30 3 CCR-IB-3S, IB-6S, IB-7S V 2 1 0 V Conservative Multiple means greater than background value near campliance boundary antl exhibits discernable plume (Figure 6-50a) T2nsition Zone - 12 28.1 2.34 3 CCR-IB-3D, GWA-S1BRU, IB-6D 2 2 0 V Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure 6-50b) Bedrock - 11 21.6 1.96 1 CCR-IB-3BR 1 1 0 V One mean greater than background value near compliance boundary, isolated occurrence (Figure 5-50c) Strontium NE (pg/L) Shallow 37 34 6.3 - 116 27 - 2272 898 26.41 5 CCR-IB-15, CCR-IB-3S, GWA-11S, IB-6S, IB-75 y 5 5 0 V Non -Conservative Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure 6-52a) T2nsition Zone 56 69 285 4.13 4 CCR-IB-3D, GWA-11BRU, IB-613, IB-7D 4 4 0 V Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure 6-52b) Bedrock 107 93 813 8.74 3 CCR-IB-3BR, GWA-SIBR, GWA-29BRA 3 3 0 V Multiple means greater than background value near compliance boundary and exhibits discernable plume (Figure 6-52c) Total Radium NE (pCi/L) Shallow 3 2 0 - 3.46 1 - 35 1.6 0.81 0 - N 0 0 0 N Variable No means greater than background value near compliance boundary T2nsition Zone 2 2 4.9 2.47 2 GWA-11BRU, I13-61) 2 1 0 V Multiple means greater than background value near compliance boundary antl exhibits discemable plume, constituent not present in ash pore water rester than back round value Fi ure 6-55a Bedrock 3 3 37.8 12.61 1 CCR-IB-3BR 1 1 1 y One mean greater than background value near compliance boundary, isolated occurrence, constituent not present in ash pore water greater than back round value Fi ure 6-SSb Total Uranium NE (pg/L) Shallow 0.0005 <000050.0002 - 0.0167 <0.0005 N/A 0 - V 0 0 0 N Non -Conservative No means greater than background value near compliance boundary T2nsition Zone 0.0005 10.1 <0.0005 N/A 0 - 0 0 0 N No means greater than background value near compliance boundaryBetlrock 0.0005 0.0016 3.20 1 GWA-I1BR 1 1 0 y One mean greater than background value, first sampling event concentration was greater than background value, but has since been less than back round value Prepared bv: T]G Checked bv: SAS o-aa ana�nt.non o e,an<a rap p a n<papn .e - noon[ Io ns a the wr hn Manpnea lI the = u cs. un ota, wnh the aaaIdan bl 111- Al, a- anshIld 11111,1111 ha N, apanan waaarva p. aarpa a< rap apn wataraa aa<p a aaoaabar 11111, a m r1111 an anm m aI 1111Q111,1011 1. IMA9/L aaadaas rr`lb-11,cb-nta- nr rag/L -m psInspar III NA hat4 a ble TABLE 6-22 SUMMARY TREND ANALYSIS RESULTS FOR MONITORING WELLS FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Wells Between Waste Boundary and Compliance Boundary Well ID Boron Lithium Sulfate Total Dissolved Solids Shallow Flow Zone GWA-10S D NT D D GWA-12S ND NT S Deep Flow Zone GWA-10D I ND D D GWA-12BRUI ND I S I S Wells Downgradient of the Source Area Near Compliance Boundary Well ID Boron Lithium Sulfate Total Dissolved Solids Deep Flow Zone CCR-IB-01S D NT NT CCR-IB-03S NT NT S GWA-11S S NT D D Deep Flow Zone CCR-IB-01D ND S S CCR-IB-03D D NT D S GWA-11BRU S D D GWA-29D ND hrr D S Bedrock Flow Zone CCR-IB-03BR S S S S GWA-29BRA ND D D S Mann -Kendall trend analysis and results prepared by Arcadis U.S. Inc. Prepared by: MAF Checked by: HES Notes: 1. Summary of results and trends are presented for samples collected from 2015 - 2019. 2. Trend results are presented when at least four samples were available and frequency of detection was >50%. Statistically significant trends are reported at the 90% confidence level. 3. Variability Index (VI) is calculated as the (maximum - minimum) / median concentration and is calculated using detected concentrations only. Values less than 1 indicate low variability in the dataset. 4. For pH, statistically significant, increasing trend with a maximum recent result (2018 - 2019) less than the lower end of the standard range or greater than the upper end of the standard range. Maximum detected result for 2018 and 2019 time period shown in parentheses. 5. Wells that had insufficient samples collected (n<4) for all four consitituents were removed from table. See designation 'NE'. 0NE = Greater than 50 percent of constituent concentrations were non -detect = Statistically significant, decreasing concentration trend = Stable. No significant trend and variability is low (VI <_ 1) = No significant trend and variability is high (VI > 1) = Statistically significant, increasing concentration trend. = Insufficient number of samples to evaluate trend (n < 4) Page 1 of 1 TABLE 6-23 SEEP CORRECTIVE ACTION STRATEGY FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Seep ID Regulatory Program General Location Approximate Average present Flow (cfs) Anticipated Seep Corrective Action Strategy Corrective action at this location may consist of capturing and treating the seep or other remedial actions. Final S-03 SOC North of U1-4 AB 0.1 corrective action plans for seeps that are not dispositioned after completion of decanting will be proposed in an amendment to the CAP Update and submitted based on the schedule outlined in the SOC. Notes: cfs- cubic feet per second NPDES - National Pollution Discharge Elimination System SOC - Special Order by Consent Prepared by: SAS Checked by: TJG Page 1 of 1 TABLE 6-24 REMEDIAL TECHNOLOGY SCREENING SUMMARY FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale COIs pose no unacceptable risk to Monitored Natural Attenuation human health or the environment under (MNA) Yes conservative exposure scenarios. MNA could be implemented in conjunction with source control measures. In -Situ Technologies Low Permeability Barriers (LPB) No Technically challenging and costly. The source of COIs has been excavated Groundwater Flushing No and the concentrations of COIs appear to be stable. Encapsulation No No area where COIs are concentrated. Permeable Reactive Barrier (PRB) No Boron is not amenable to treatment in a PRB. Groundwater Extraction Technologies The source of COIs has been excavated Vertical Extraction Wells No and the concentrations of COIs appear to be stable. Horizontal or Angular Extraction The source of COIs has been excavated Wells No and the concentrations of COIs appear to be stable. The source of COIs has been excavated Extraction Trenches No and the concentrations of COIs appear to be stable. Hydraulic Fracturing No Not warranted based upon the limited extent of COIs in bedrock. Groundwater extraction by TreeWelISTM Phytoremediation Yes could act as a barrier to mitigate COIs to the Broad River. Groundwater Treatment Technologies No extraction of groundwater is pH Adjustment No anticipated for Former Units 1-4 Ash Basin. No extraction of groundwater is Precipitation No anticipated for Former Units 1-4 Ash Basin. Page 1 of 2 TABLE 6-24 REMEDIAL TECHNOLOGY SCREENING SUMMARY FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale No extraction of groundwater is Ion Exchange No anticipated for Former Units 1-4 Ash Basin. No extraction of groundwater is Membrane Filtration No anticipated for Former Units 1-4 Ash Basin. Management of Extracted Groundwater NPDES Permitted Discharge No Groundwater extraction is not retained Publicly Owned Treatment Works No Groundwater extraction is not retained (POTW) Non -Discharge Permit/Infiltration No Groundwater extraction is not retained Gallery Non -Discharge Permit/Land No Groundwater extraction is not retained Application Beneficial Reuse Fire Protection No Groundwater extraction is not retained Non -Contact Cooling Water No Groundwater extraction is not retained Dust Suppression and Truck Wash No Groundwater extraction is not retained Prepared by: TJG Checked by: JEC Page 2 of 2 TABLE 6-25 REMEDIAL ALTERNATIVE 2 TREEWELL SUMMARY FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Phytoremediation and TreeWell Technology System Number of TreeWells Flow Zone Total Depth (ft bgs) 286 Saprolite/Transition Zone 30-40 Groundwater removal projections for TreeWell system: Groundwater removal rate of the system will be approximately 3.1 million gallons per year upon reaching maturity Notes• ft bgs - feet below ground surface gpm - gallons per minute Prepared by: VTV Checked by: GTC Page 1 of 1 TABLE 6-26 ENVIRONMENTAL SUSTAINABILITY COMPARISONS FOR REMEDIATION ALTERNATIVES FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS LLC, MOORESBORO, NC Remedial Alternative Remedial Alternative 1 — Groundwater Remediation by MNA Remedial Alternative 2 — Groundwater Remediation by TreeWellsTM Emissions Units CO2 Emissions metric ton 2.07E+01 -1.74E+02 Onsite NO, emissions metric ton 2.43E-02 1.54E-01 Onsite SOX Emissions metric ton 2.48E-03 1.58E-02 Onsite PM,() Emissions metric ton 2.19E-03 1.39E-02 Total NOx emissions metric ton 4.25E-02 1.81 E-01 Total SOx Emissions metric ton 1.34E-02 3.27E-02 Total PM,() Emissions metric ton 3.88E-03 1.70E-02 Total Energy Used MMBTU 3.88E+03 4.06E+03 Total Emissions metric ton 2.08E+01 -1.73E+02 Prepared by: GTC Checked by: SJB Notes: CO2 - Airborne emissions of carbon dioxide MMBTU - Million British Thermal Units NOX - Airborne emissions of nitrogen oxides (combination of nitrogen monoxide and nitrogen dioxide) SOX - Airborne emissions of sulfur oxides (combination of sulfur monoxide, sulfur dioxide, sulfur trioxide, and others) PM10 - Airborne emissions of particulate matter that is 10 micrometers or less in diameter Page 1 of 1 TABLE 6-27 EFFECTIVENESS MONITORING PLAN ELEMENTS FORMER UNITS 1-4 ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Effectiveness Monitoring Plan (EMP) Post -Closure Monitoring Plan (PCMP) Implemented 30 days after CAP Approval Implemented after completion of ash basin closure activities EMP Groundwater Well Monitoring Network (background, downgradient of source areas) Performance Monitoring Network CCR-I13-1S GWA-10S IB-6S CCR-IB-11D GWA-IOD IB-6D CCR-IB-3S GWA-11S IB-6BR* CCR-IB-3D GWA-11BRU I13-7S CCR-IB-3BR GWA-11BR I13-7D Background Monitoring Wells' GWA-30S MW-30DA MW-32D GWA-30BR MW-32S MW-32BR MW-30S EMP Groundwater Quality3• ° (Semi -Annual Sampling Frequency) Alkalinity Ferrous Iron Sodium Aluminum Iron Strontium' Arsenic' Lithium' Sulfate Bicarbonate Alkalinity Magnesium Total Dissolved Solids' Boron' Manganese' Total Organic Carbon Calcium Nitrate + Nitrite Total Radium' Cobalt' Potassium Vanadium' PCMP Groundwater Well Monitoring Network (background, downgradient of source areas) A PCMP will be implemented at the Site in accordance with G.S. 130A-309.214(a)(4)k.2 after completion of ash basin closure activities. PCMP Groundwater Quality (Sampling frequency to be determined) Parameters and sampling frequency to be included in the PCMP in accordance with G.S. 130A-309.214(a)(4)k.2 when submitted. CMP and PCMP Groundwater Field Parameters Water Level Specific Conductivity Temperature pH Oxidation Reduction Potential Dissolved Oxygen EMP Review Annual Effectiveness Monitoring Evaluation and Reporting 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation of compliance with applicable Standards 4) Evaluation of system performance and effectiveness 4) Recommend plan adjustments, if applicable, to optimize the remedial action 5-Year Performance Review Reporting 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Re-evaluate effectiveness of technology 4) Verify modeling results, update model if needed 5) Modify corrective action approach, as needed, to achieve compliance goal established 30 days after CAP approval, the EMP will be implemented at the Site and will continue until there is a total of three years of data confirming COIs are below applicable Standards at or beyond the compliance boundary, at which time a request for completion of active remediation will be filed with NCDEQ. If applicable standards are not met, the EMP will continue and transition to post -closure monitoring if necessary. PCMP Review Annual Evaluation and Reporting 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation 02L compliance 4) Recommend plan adjustments, if applicable At a frequency no greater than 5 years: 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Verify model results, update if needed After ash basin closure and following ash basin closure certification, a PCMP will be implemented at the Site for a minimum of 30 years in accordance with G. S. 130A-309.214(4)(k)(2). Early termination: If groundwater monitoring results are below applicable Standards at the compliance boundary for three years, Duke Energy will request completion of corrective action in accordance with G.S. 130A- 309.214(a)(3)b. If groundwater monitoring results are above applicable Standards, the PCMP will continue. ' Approved background groundwater monitoring locations 2 Corrective action COIs to monitor plume stability and physical attenuation either from active remedy or natural dilution/dispersion 3 The number of monitoring wells and parameters may be adjusted based on additional data and the effects of corrective action. " Groundwater standards may be modified over time in accordance with 02L .0106(k) * Proposed new well Italicized parameters - parameters for general water quality to evaluate monitoring data quality wells indicated in red will have geochemical sondes placed to monitor geochemical condition: Prepared by: TJG Checked by: SAS Page 1 of 1 Corrective Action Plan Update December 2019 Cliffside Steam Station Source Area 3 (Unit 5 Inactive Ash Basin) SynTerra TABLE 6-28 BORON CONCENTRATIONS IN GROUNDWATER BELOW SOURCE AREA UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Boron Boron Well Beneath Number Concentration Concentration Ash of Time Period Range Range in (Flow Zone) Sample of Record Groundwater Overlying Pore Events Water (Ng/1) (pg/1) U5-2BR (Bedrock) 13 03/2016 - 01/2019 58.3 - 140 192 - 470 (-10' saturated U5-2D 16 06/2015 - 01/2019 109 - 286 ash) (Deep) U5-7D 170 - 190 (Deep) 6 06/2015 - 06/2016 103 - 160 (-50' saturated ash) Prepared by: TJG Checked by: SAS Page 1 of 1 TABLE 6-29 SUMMARY OF UNSATURATED SOIL ANALYTICAL RESULTS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameters pH Arsenic Boron Chromium Cobalt Iron Manganese Strontium Sulfate Thallium Vanadium Reporting Units S.U. mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg PSRG Protection of Groundwater NE 5.8 45 3.8 0.9 ISO 65 1,500 1,438 0.28 350 Background Threshold Values 4.0-6.8 7.8 31 142 48 74,362 672 9.9 13 1.1 161 Sample ID Sample Collection Date Analytical Results Background BG-02D (3.5 - 5) 02/23/2015 5.5 j <3.5 <69.4 84 15.2 61,500 234 1.1 <353 <1.4 110 BG-02D (8.5 - 10) 02/23/2015 5.2 j 3.3 j 18.4 j- 85.5 22 39,100 591 j <3.2 <310 <3.2 75.7 BG-02D (18.5 -20) 02/23/2015 5.5j 3.4j 21.7 109 19.3 22,000 415 <0.83 <400 <4.2 60.1 BG-02D (28.5 - 30) 02/23/2015 5.7j 3.5 <16.9 71.2 25.6 16,600 517 0.9 <330 <1.4 52.9 BGSB-MW-30(6-7) 10/17/2017 5.2 4.3 B <9.6 M 120 6.2 73,000 M 160 16 <13 0.39 180 B BGSB-MW-30(14-15) 10/17/2017 5.2 2.7 B <5.9 91 30 49,000 190 0.89j <13 0.32 130 B BGSB-MW-30(24-25) 10/17/2017 5.6 0.73 B <15 94 12 38,000 390 <6.2 <13 M 0.41 83 B BGSB-MW-32(2-3) 10/19/2017 4.8 12 <14 69 2.4 44,000 B 40 6.9 35 0.31 89 BGSB-MW-32 (14-15) 10/19/2017 4.4 6.4 <4.8 41 2.6 40,000 B 130 0.6j <12 0.15 71 MW-30D (3.5 - 5.5) 02/23/2015 5.9 j 3.2 j <3.9 79.9 7.3 48,500 145 1.1 <394 <1.6 97.8 MW-30D (8.5 - 10) 02/23/2015 6.0 j 2.4 j <4.1 48.1 3.3 j 27,300 89 1.6 <396 <4.1 70.3 MW-30D (18.5 - 20) 02/23/2015 5.0 j 3.5 j <4.7 80.6 2.4 j 60,600 215 <0.94 <488 <1.9 125 MW-30D (28.5 - 30) 02/23/2015 6.1 j 3.6 j 27.3 j 88.6 36.1 38,700 979 <7.7 <380 1 j 93.8 MW-32D (3.5 - 5) 02/23/2015 5.2 j 3.8 <30.1 79.8 5.7 48,700 148 1.4 204 j <1.2 96.7 MW-32D (8.5 - 10) 02/25/2015 6 j 1.9 j <30.6 50.5 6.7 44,800 107 2 <309 <1.2 74.5 MW-32D (18.5 - 20) 02/25/2015 5.9 j 1.7 <3.3 3.7 3.2 2,760 62 13.3 <321 <1.3 3 MW-32S (22.5 - 24) 03/12/2015 6.3 j <38.9 116 33.8 46,400 910 1.4 j+ <387 <3.9 90.1 MW-42D (28.5 - 30) 1 02/23/2015 1 6.6j 1.8 <4 85.4 13.1 21,600 321 7.1 1 <423 0.89j 50.9 Beyond Ash Basin Waste Boundary GWA-03D (48.5 - 50) 04/16/2015 6.5 j 3.9 j- <17.9 17.9 42,800 463 4.5 <355 <7.2 105 GWA-05BRU (13.5 - 15) 02/23/2015 5.7 j 2.6 j <19.7 129 25.2 26,700 498 2.7 <386 0.84 j 85.8 GWA-05S (13.5 - 15) 03/06/2015 NA NA NA NA NA NA NA NA NA NA NA GWA-06D (28.5 - 30) 05/08/2015 6.0 j <9.7 <24.2 130 20.7 32,800 601 10.1 <466 <9.7 78.8 GWA-31BR (4 - 4) 04/21/2015 7.1 j 1 7.7 31.3 98.8 17.5 35,200 401 5.5 <317 1 <6.6 79.9 GWA-31D (7 - 7) 04/23/2015 10.7 j <5 20.9 69.2 5.8 22,900 266 2 j 135 j <5 61.5 GWA-31D (8.7 - 8.7) 04/23/2015 11.5 j 4.5 j 41.6 43 7.1 15,500 403 115 162 j <5.3 37.1 GWA-32D (11.7 - 11.7) 06/05/2015 5.8 j <5.3 <13.2 <1.3 <5.3 1,720 13.2 <2.6 <264 <5.3 <5.3 MW-38D (33.5 - 35) 03/02/2015 6.0 j 3 <3 16.3 43.7 15,100 317 4.1 <298 <1.2 31.7 MW-38S (33.5 - 35) 03/04/2015 NA NA NA NA NA NA NA NA NA NA NA MW-40BRU (3.5 - 5) 03/30/2015 <6.1 <15.2 89.2 22.2 31,100 411 3.9 <295 <6.1 71.6 Prepared by: TJG Checked by: VJH Notes: 0 - Bold highlighted concentration indicates exceedance of the Inactive Hazardous Sites Branch PSRG Table (May 2019) for Protection of Groundwater or the Background Threshold Value (BTV), whichever is higher. < - Concentration not detected at or above the adjusted reporting limit. B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than SOX the concentration in the method blank. Analyte concentration in sample could be due to blank contamination. j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit. j- - Estimated concentration, biased low. j+ - Estimated concentration, biased high. M - Matrix spike / matrix spike dup failure. mg/kg - milligrams per kilogram NA - not analyzed NE - not established PSRG - preliminary soil remediation goals S.U. - standard units Page 1 of 1 TABLE 6-30 SOURCE AREA INTERIM ACTIONS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Groundwater Remedy Rationale Component Source Area U5 AB main dam modifications including the installation of a new Stabilization spillway. Prepared by: SAS Checked by: TJG Page 1 of 1 TABLE 6-31 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L mg/L Ng/L mg/L pCi/L Ng/L Ng/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 - 6.1 1 50 0.5 4 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone)2 4.0 - 6.0 0.2 50 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range (Shallow Flow Zone)2 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7 - 1000 6.8- 103 <1 - 5.5 <0.1 - 0.3 <25 - 1070C 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 - 6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone)2 4.9 - 7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range (Deep Flow Zone)2 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4- 7.41 1 50 1 0.1 1 4 1 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone)2 4.5 - 7.51 1 1 50 1 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range (Bedrock Flow Zone)2 4.8 - 7.6 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID Flow Zone Mean, Geomean, or Median Result3 Background Locations GWA-30S Shallow 5.7 0.1 < 50 0.041 1.3 5.0 264 1.1 269 24 < 1 0.2 43 - - < 0.3 MW-30S Shallow 5.3 0.1 < 50 3.120 3.0 0.4 159 1.2 8 10 < 1 < 0.1 33 0.490 < 0.0005 < 0.3 MW-32S Shallow 5.0 0.1 < 50 0.177 0.6 1.1 73 2.5 37 27 < 1 0.1 59 1.206 < 0.0005 < 0.3 CCPMW-01S Deep 5.3 < 0.1 < 50 0.324 0.8 2.2 53 2.0 42 < 5 < 1 < 0.1 < 25 0.138 < 0.0005 0.3 MW-30D Deep 8.3 1.6 < 50 0.076 < 0.5 < 0.1 53 11.1 8 61 16 < 0.1 107 2.13 0.0003 10.0 MW-30DA Deep 6.7 0.2 < 50 < 0.025 0.6 0.8 241 10.2 219 65 10 < 0.1 116 0.420 < 0.0005 0.3 MW-32D Deep 5.9 0.1 < 50 0.034 < 0.5 1.8 < 50 2.8 11 40 7 < 0.1 73 0.526 < 0.0005 < 0.3 CCPMW-01D Bedrock 5.2 < 0.1 < 50 0.056 < 0.5 0.3 < 50 1.1 8 22 1 < 0.1 40 0.693 < 0.0005 < 0.3 GWA-30BR Bedrock 6I 0.2 < 50 < 0.025 0.7 < 0.1 7198 3.6 70 52 14 < 0.1 90 0.2 MW-32BR Bedrock 7.0 0.1 < 50 < 0.025 0.8 < 0.1 5305 6.1 33 57 16 < 0.1 103 < 0.249 < 0.0005 < 0.3 Within the Waste Boundary Locations U5-02S-SLB Ash Pore Water 6.6 5175.0 267 < 0.025 0.6 11.9 67850 54.9 643 1865 145 1.3 429 0.145 0.0110 0.6 U5-01S Shallow 6.2 4.2 < 50 < 0.025 0.7 7.5 54348 < 0.5 4504 138 5 < 0.1 217 - - 0.5 U5-04S Shallow 5.4 0.2 135 2.640 3.8 1.5 353 1.2 23 14 22 < 0.1 77 0.4 U5-06S Shallow 4.2 0.6 158 < 0.025 21 107 4010 8.8 5480 374 167 0.5 301 1.0 U5-08S Shallow 6.5 12.0 < 50 < 0.025 < 0.5 1.1 6580 < 0.5 2980 150 27 < 0.1 211 < 0.3 U5-01D Deep 6.5 0.5 < 50 0.094 < 0.5 1.0 232 20.7 221 68 3 0.1 129 - - 1.6 U5-02D Deep 6.7 4170 125 0.034 0.6 3.1 36740 16.7 872 1440 86 < 0.1 338 1.5 < 0.0005 < 0.3 U5-04D Deep 7.3 1.4 < 50 0.105 1.7 0.3 456 9.6 28 113 65 < 0.1 183 - - 1.3 U5-05D Deep 6.3 1.4 331 0.035 3.1 19.2 11632 28.7 3222 186 194 < 0.1 422 3.3 0.0019 0.5 U5-06D Deep 5.7 1.0 162 0.029 1.1 28.0 14182 21.4 1442 408 163 0.1 319 - 1.2 U5-08D Deep 10.1 0.1 < 50 1.068 1.3 0.2 < 50 1.6 8 39 2 < 0.1 72 - 0.7 U5-02BR Bedrock 6.0 164 120 < 0.025 1.2 25.1 6266 1.3 5910 396 22 0.3 195 0.0011 0.4 U5-046RA Bedrock 10.6 2.0 < 50 0.580 0.5 0.3 113 9 57 18 < 0.1 108 - 1.4 U5-0513R Bedrock 1 8.9 11.7 447 0.057 2.0 2.1 59 67.1 31 1342 555 < 0.1 1424 9.6 U5-08BR Bedrock 10.0 3.9 < 50 0.690 1.4 0.6 47 11.3 < 5 33 13 < 0.1 124 - 2.6 Between Waste Boundary and Compliance Boundary Sidegradient of the Ash Basin CCR-U5-10S Shallow 5.0 < 0.1 4 2.5 1.7 - 1.2 - - < 1 < 0.1 52 0.642 - GWA-05S Shallow 5.2 0.4 < 50 1.320 3.2 2.8 122 1.9 410 113 532 0.4 793 - 0.3 CCR-U5-10D Deep 5.5 < 0.1 10 1.3 0.8 - 0.9 15 0.1 88 0.277 - GWA-05BRU Dee 7.3 0.4 < 50 0.073 0.6 < 0.1 172 8.4 195 207 53 < 0.1 433 - 0.4 Downgradient of the Ash Basin CCR-U5-03S Shallow 5.9 < 0.1 94 0.579 1.5 0.2 102 0.4 290 165 50 < 0.1 169 - 0.3 CCR-U5-04S Shallow 5.4 1.2 563 1.200 1.9 83.7 683 5.2 1830 550 182 0.5 338 0.366 0.6 CCR-U5-06S Shallow 4.0 0.3 139 - < 0.5 33.3 - 8.0 - 150 0.6 289 1.4 - - CCR-U5-08S Shallow 5.6 0.4 17 2.6 25.1 1.0 218 0.2 372 0.459 CCR-U5-09S Shallow 5.2 < 0.1 324 - 0.6 5.2 1.4 - - 12 0.1 61 0.827 - GWA-02S Shallow 5.5 < 0.1 129 0.202 < 0.5 0.2 203 0.5 206 129 65 0.1 181 0.331 < 0.0005 < 0.3 GWA-04S Shallow 4.3 0.8 159 < 0.025 < 0.5 59.4 18260 5.8 2014 537 194 1.3 343 1.5 < 0.0005 < 0.3 GWA-36S Shallow 5.3 1.2 79 < 0.025 0.5 51.6 1851 7.5 1028 234 109 0.6 206 0.613 < 0.0005 < 0.3 CCR-U5-01D Deep 5.9 < 0.1 7 - 0.7 1.4 - 1.1 - - 53 < 0.1 195 1.3 - - CCR-U5-02D Deep 5.3 0.1 80 - 4.3 0.7 - 0.9 - 43 0.1 116 < 0.28 - CCR-U5-03D Deep 5.8 0.1 127 0.153 0.6 2.8 297 0.4 2033 253 72 0.2 212 1.3 0.3 CCR-U5-04D Deep 5.2 0.6 800 < 0.025 < 0.5 61.3 IF 1605 6.8 3620 555 341 0.9 529 1.6 0.4 CCR-U5-06DA Deep 4.6 0.1 173 - < 0.5 107 - 1.0 - - 219 0.2 401 0.521 - CCR-U5-08D Deep 4.6 1.1 189 - 1.8 179 17.8 - - 463 2.4 981 1.7 - - GWA-02BRU Deep 6.2 0.2 127 < 0.025 < 0.5 0.5 431 10.7 115 158 69 < 0.1 269 1.2 0.0005 < 0.3 GWA-03D Deep 5.7 0.2 400 0.362 2.0 3.3 174 4.7 1464 233 184 0.1 362 1.6 < 0.0005 0.6 GWA-04D Deep 5.4 0.4 165 < 0.025 < 0.5 93.9 16200 7.4 4320 449 232 < 0.1 433 4.3 0.0007 < 0.3 GWA-31D Deep 6.7 0.4 46 0.214 0.7 0.3 91 4.4 6 461 381 < 0.1 874 7.5 - 0.4 GWA-36D Deep 5.6 0.4 165 < 0.025 0.5 37.4 1368 5.6 4436 323 308 < 0.1 572 0.707 < 0.0005 0.4 CCR-U5-04BR Bedrock 6.8 0.5 1 414 < 0.025 0.9 0.1 7120 9.0 598 281 258 < 0.1 577 2.7 0.0003 0.4 Page 1 of 2 TABLE 6-31 MEANS OF GROUNDWATER COIs - JANUARY 2018 TO JUNE 2019 UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTIVE PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Analytical Parameter pH Arsenic Boron Chromium (VI) Chromium Cobalt Iron Lithium Manganese Strontium Sulfate Thallium Total Dissolved Solids Total Radium Total Uranium Vanadium Reporting Units S.U. Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L Ng/L mg/L Ng/L mg/L pCi/L Ng/L Ng/L 15A NCAC 02L Standard 6.5 - 8.5 10 700 NE 10 1* 300 NE 50 NE 250 0.2* 500 NE NE 0.3* 2017 Background Threshold Values (Shallow Flow Zone)' 4.4 - 6.1 1 50 0.5 4 11 684 NE 169 37 1 0.1 75 3 0.0005 1 2019 Background Threshold Values (Shallow Flow Zone)2 4.0 - 6.0 0.2 50 4 26 21 1700 3 969 34 4 0.2 57 2 0.0005 1 2019 Background Dataset Range (Shallow Flow Zone)2 3.3 - 6.1 <0.1 - 0.73 <50 <0.025 - 4.8 <0.5 - 26.2 0.16 - 22.9 <50 - 5750 <0.5 - 4.6 6.7 - 1000 6.8 - 103 <1 - 5.5 <0.1 - 0.3 <25 - 1070C 0.0976 - 1.961 <0.0002 - <0.0005 <0.3 - 1.9 2017 Background Threshold Values (Deep Flow Zone)' 4.8 - 6.1 1 50 0.2 2 5 515 NE 78 56 10 0.1 71 2 0.0005 1 2019 Background Threshold Values (Deep Flow Zone)2 4.9 - 7.2 2 50 0.6 2 5 1840 12 260 69 15 0.2 107 2 0.0005 11 2019 Background Dataset Range (Deep Flow Zone)2 3.8 - 7.3 <0.1 - 2 <50 - 150 <0.025 - 1.2 <0.5 - 9.9 <0.1 - 6.1 <50 - 3200 1.5 - 13.4 5.2 - 408 6.3 - 70.5 <1 - 18.5 <0.1 - <0.2 <25 - 407 0.017 - 2.323 <0.0005 <0.3 - 12.2 2017 Background Threshold Values (Bedrock Flow Zone)' 5.4- 7.41 1 50 1 0.1 1 4 1 1 6220 NE 89 107 15 0.2 120 3 0.0005 0.4 2019 Background Threshold Values (Bedrock Flow Zone)2 4.5 - 7.51 1 50 1 0.7 3 2 7680 11 113 93 17 0.2 120 3 0.0005 1 2019 Background Dataset Range (Bedrock Flow Zone)2 4.8 - 7.61 <0.1 - 1.2 <50 - 83 <0.025 - 0.8 <0.5 - 10.5 <0.1 - 2.6 <50 - 11000 1.1 - 7.3 5 - 134 16.6 - 116 <1 - 17.6 <0.1 - 0.5 <25 - 330 0 - 3.46 <0.0005 <0.3 - 1.5 Sample ID Flow Zone Mean, Geomean, or Median Result3 CCR-U5-05D Bedrock 6.9 1.1 384 - 0.7 5.4 4.5 - - 151 < 0.1 452 < 0.599 - - GWA-02BRA Bedrock 8.2 0.6 85 < 0.025 1.0 0.1 852 5.4 125 117 48 < 0.1 209 1.7 0.0004 0.7 GWA-31BRA Bedrock 7.8 1.7 < 50 0.031 1.0 < 0.1 278 35.3 55 52 112 < 0.1 302 < 0.518 - 0.5 GWA-67BR Bedrock 11.8 - < 50 - - - - - - - - - - - GWA-67BRL Bedrock 7.4 0.2 133 < 0.025 < 0.5 0.1 1825 8.8 197 174 76 < 0.1 241 3.7 0.0004 0.4 GWA-68BRL Bedrock 7.7 0.3 68 0.060 < 0.5 0.1 276 9.0 116 306 95 < 0.1 302 1.5 0.0019 0.6 Near or Beyond Compliance Boundary Upgradient of the Ash Basin IF MW-42S Shallow 5.6 0.2 < 50 0.850 2.6 0.3 178 0.5 11 45 7 < 0.1 67 - < 0.0005 < 0.3 GWA-45D Deep 8.2 0.9 < 50 < 0.025 1.2 0.1 118 - 24 136 27 < 0.1 201 - 2.6 MW-42DA Deep 7.2 0.7 < 50 0.079 0.8 0.3 152 36.5 43 112 105 < 0.1 302 0.0019 1.0 Downgradient of the Ash Basin GWA-34S Shallow 5.9 0.1 < 50 0.047 < 0.5 0.3 385 0.7 65 19 2 < 0.1 53 < 0.0005 < 0.3 GWA-35S Shallow 5.8 0.7 110 < 0.025 < 0.5 16.9 16040 < 0.5 1692 50 41 0.1 131 - < 0.3 GWA-37S Shallow 5.8 0.9 80 < 0.025 1.3 92.7 15860 0.6 7866 74 71 0.1 182 - 0.3 GWA-56S Shallow 6.1 0.2 < 50 0.383 1.8 2.1 820 1.3 146 66 138 < 0.1 314 0.435 < 0.0005 0.4 MW-34S Shallow 5.2 < 0.1 < 50 0.063 < 0.5 1.2 130 1.2 25 5 < 1 < 0.1 < 25 - < 0.0005 < 0.3 MW-36S Shallow 5.7 0.1 57 0.200 0.6 < 0.1 261 0.4 15 41 10 < 0.1 57 - - 0.4 MW-38S Shallow 5.3 0.1 126 0.540 1.5 3.7 377 1.1 366 81 153 < 0.1 276 0.655 < 0.0005 0.3 MW-40S Shallow 5.5 < 0.1 < 50 0.694 1.2 0.6 356 0.6 28 158 113 < 0.1 247 - - 0.6 GWA-01BRU Deep 7.1 0.1 < 50 0.067 0.6 0.2 795 3.0 59 45 8 < 0.1 95 - < 0.3 GWA-32D Deep 6.0 0.1 < 50 0.097 < 0.5 0.1 124 0.6 10 11 2 < 0.1 27 0.0002 < 0.3 GWA-35D Deep 6.4 0.1 128 < 0.025 < 0.5 0.5 4578 10.5 119 112 63 < 0.1 189 - < 0.3 GWA-37D Deep 5.3 0.2 62 0.685 11.1 1.3 925 11.6 48 587 289 < 0.1 541 - - 1.5 GWA-56D Deep 6.5 0.2 < 50 < 0.025 1.4 0.6 1547 16.5 290 169 114 < 0.1 312 3.0 < 0.0005 0.3 MW-34BRU Deep 7.4 0.1 < 50 0.028 < 0.5 < 0.1 783 1.3 40 64 12 < 0.1 118 - - < 0.3 MW-36BRU Deep 6.9 < 0.1 < 50 0.026 < 0.5 < 0.1 216 2.9 67 71 7 < 0.1 121 - - < 0.3 MW-38D Deep 5.8 0.2 233 0.109 1.1 2.6 196 7.8 398 211 232 < 0.1 424 1.2 < 0.0005 0.5 MW-40BRU Deep 7.7 i 0.5 < 50 0.082 < 0.5 < 0.1 159 2.9 196 201 98 < 0.1 298 4.6 - 0.5 GWA-34BR Bedrock 8.0 0.1 < 50 < 0.025 < 0.5 0.1 1057 1.5 80 66 28 < 0.1 163 - < 0.0005 < 0.3 MW-38BR Bedrock 6.6 1 0.8 - < I 1.0 0.9 2358 16.1 252 378 254 < 0.1 509 3.3 < 0.0005 < 0.3 Notes: 1 - Background threshold values were calculated using data from background groundwater samples collected June 2015 to September 2017. z - Background threshold values were calculated using data from background groundwater samples collected March 2011 to December 2018. 3 - Statistical mean, geomean, or median calculated from data ranging from January 2018 to June 2019. Ash pore water results are not compared to groundwater standards or criteria. Mean or geomean results were used based on the central tendency of the data set. For wells with datasets containing fewer than four valid results, the most recent valid sample data was used. Means were calculated for wells with four or more valid sample results. Sample results were excluded from calculations: 1) if turbidity >10 NTU (for COIs other than boron) 2) for unusable data (RO qualified) 3) if a result was non -detect at a reporting limit (RL) greater than the normal laboratory RL Bold text - Constituent concentration exceeds applicable comparison criteria. 0 - bold highlighted concentration indicates value is greater than the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202 Standard and IMAC is April 1, 2013) bold highlighted concentration indicates value is greater than greatest background threshold value where there is no regulatory standard, or background threshold values are greater than regulatory standard 0 - highlighted concentration indicates value is either within range of background threshold values for constituents where there is no regulatory standard/background threshold values are greater than regulatory standard, or within range of background threshold value and the regulatory standard * - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013. < - concentration not detected at or above the adjusted reporting limit. - - value not available NE - not established mg/L - milligrams per liter pCi/L - picocuries per liter Pg/L - micrograms per liter S.U. standard unit Prepared by: TJG Checked by: TAW Page 2 of 2 TABLE 6-32 COI MANAGEMENT MATRIX UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Sm.a.d.—I Maximum Mean Number of Wall.• Zone Statistically Clinside Steam c Constituents of St' pi.d...t Concentration Near E.o.—mo. Above Criterion Near Regulatory Sit d Groundwater Monitoring Wall, With COI Concentration .1. 't"" 'ad"m""d a.kgr ... d Beyond B,y,, Criterion (2028 CSA Updal.) Derivad Ba.kg...d V, Ista,mt Nan.. All Greater Than Comparative Criteria Flow Zone,) Value Range Compiler-• compliance B ... daW 1*"nd.ry Flo —me Constituent Stericlairds and Values - 02L Criterion 6�, 'e 01 , moo 0, 41 F as P, 'e' 101 ".111 '44111h. sp, Lines of Evidence (LOE) - 02L Criterion Rationale for Selection of COI, for Corrective Action Evaluation (for constituents where no means are gre,1,rt1,n=.p.r=cri ana in all flow zones nd/ormul 1e lines of evidence support that con rimm..s are not related P hit to the source area, no corrective action is warranted) Rationale - 02L Criterion No means greater than 02L standard near or beyond compliance bo,nda,, No means greater than 02L standard near or beyond compliance bo,nda,y No means greater than 02L standard rear or beyond compliance No means greater than 02L standard, ho—er bono. greater than the backly—nd value is a potential indicator of ash basin infl,ence (Figure 6-75a) No means greater than 02L standard, ho.eaer b—n greater than the background aalue is a potential indicator of ash basin influence (Figure6-75b) No means greater than 02L standard, ho.eaer boom greater than the background aalue is a Potential ind[cator of ash basin influence (FiI No. --ti- No nnaams greater the, background value n,,r,r beyond compliance b ... dary One son greater than D21- standard, i,ol.md c.—mo, c—stit.rnt mut pr ... ntgr,,t,rth,.,,.p,r,ti,,,riteria in ash pone -ter (Fig-6-76) No means greater than 02L standard near or beyond compliance I ..�tip�e-.ans�-a-rlhanba�k�m�.d-al..n.aror�-nd--�'ian�.bo,nda�andi,.hibitsdiscernablepl,,e (FigumG-79a) One son greater than backgro—ol a,1 .. ... r.rb.y..d,,�plian�bo,nda�,e.hbi�di,��,bi,pi,�e (FigumG-79b) No means greater than ba,kgro,nd �al- near,r beyond compliance boundary Multiple means ii-aterhan ba�lkgrau.d-l.e n—orb-nd —,liam- mmd.- and ..hibits dismmabi. (FigumG-81a) Multiple means greater than backii—nd value near or beyond compliance lb—da,, and e.hrits discernable pl,nne (Figure681b) gym® ®moo 0000 One son greater than background �al,e near or beyond em,pliance no,ndary, e.hibits discernable plunae (Figure681c) moo ®moo 000© No means gr aterrana. .21- -ends- near or be,ond compliance bourdar,, s-1, g-utcrtha. b.ckg-.nd value roapped (Figur.6-83.) One son greater than 02L standard near or beyond coropli,rco b-nd a.hibit, discernable plunne (FigumG-83b) One son greater than 02L standard near or beyond compliance boundary, e.hibits discernable plunne (Figure 6-83c) Totsl ti,sol—d Solid, No means gr ater the. .21- -ends- near or be,ond compliance bounce-, TDS greater than background aalue -upped (Figure 6-8") One son greater than 02L standard near or beyond compliance boundary, e.hibits discernable plunne (Figure 6-84b) On,,,angr,,�rth,nO2L�nd,rdn,ar,rb,y,,d��plianc.b..nd.�,..hibit�di�c.rnabl�pi..e (Fig-6-84c) Constituent Standards and Values - IMAC Criterion Lines of Evidence (LOE) - IMAC Criterion Rationale - IMAC Criterion Cma -.an greater than background value na—r beyond compliance bound.-, a.hibi- dis-mal,I. plunne (FIgurall-1111) No h:n b kg�:und n::r b ad an b: und:ry "P v:�u c: b IN gre: n b:c no :� bd �i nc und . :" " ::r:h ck u u: n ':n rY ��®��mo No boundary yondd c..phance No re: MA p an' bound:ry 'means 000©� No IMAC greater than AC near or beyond c.'p�i n bound greater than backgra near or beyond compliance boundary m::n: NN: greater than backgr.undd :�ue u n b ad an b: u nd:ry mmeans r:�b a tam c: greater than backg—nd valu: n::r :yy.nd oamp�i.nc und rY b No Constituent Standards and Values - Background Criterion Lines of Evidence (LOE) - Background Criterio�� Rationale - Background Criterion Chromium (H ... -lent) means greater than back.—nd value near or beyond campliance boundary Cm, mcon greater than lackground .,,,No C—ti— bact out p—ort gromerthen ruckgrourd ml., in ash p., —or, mean is also ithin mage ofosel, flo—oaa kgr ... d ccrcantratl— detected at Oftid, (Figure 6-77) Imo 000©n No means greater than background value near or beyond camplilmc, boundary On. mean greater than background value near or beyond compliance bo ndI location probably not influenced by ash baein, dist—able plume -ists ithin the -ste aboundan, (Figure 6,110b) One —an greater than background �alue near or beyond coropli—, bourdury (Figure 6-80c) -W-g-1 —1 6S, MW-38S, Msa-40S Multiple means greater than backgmand value near or bayand compliance b-indI a.hibits discarnable pl.me (filters I :nd Munti'le means greater than background va us near or beyond compliance bounds, d e.hrits discernable plunne (Figure 6-112b) one mean greater than background c,r.r baymnd compliance b—d,ry, u.1-ints an ... mable plurae (Figure 6-82,) No means greater the. background alu, near or beyond wroplia... houncery ©©�®��© ©000 T.. me n. greater than background v,lu indicatwe of a�sh cbZsrratinlac ticas GWA-S61) and HW-40BRU, hich am outside the dI b,rn plum, and therefore probably not :mm. Constituent not present in ash om �mterqmatertham background �albua ©a ®moo 0000 One mean greater than background value naaror beyond compharc. bound.-, is. led ccurn-. Constituent not present in ash pare -.-rgmat.rthan Is backumurd al- (Figure 6-85 No means greater than b , near or n '.'.p�ii:n�: No means greater than b r: �:�u: nearer bb:yy.ndd ::kk,,r undd bb:und:', No mc__mc, than unckar—d mluu maerm- bcy..d compliance b—cm, u -d:n. r, 1,1 1, rio arld In - —a — upaut, .11, ur, eaakpn p1 Inhl— d—b1ld 11111, 1111 t'Irahl.11 de, -1 111ple, <m eaea 11—r 1111 t, I 1111Q I ... 1111 _nn.em.r i. g—r sae per ner 11c ble Y-1 Wells Within the Waste Boundary Well ID Boron Lithium Sulfate Total Dissolved Solids Shallow Flow Zone US-01S ND ND D U5-08S S S D D Deep Flow Zone U5-01D ND D D U5-0213 D I S I S D US-08D D I S I D r NT Bedrock Flow Zone US-02BR S U5-08BR I S I NE I NE I NE TABLE6-33 SUMMARY TREND ANALYSIS RESULTS FOR MONITORING WELLS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Wells Between Waste Boundary and Compliance Boundary Well ID Boron Lithium Sulfate Total Dissolved Solids Shallow Flow Zone CCR-US-03S S D D D CCR-US-04S 5 NT S S CCR-US-06S D D D S CCR-U5-OSS T D NT S CCR-US-095 S NT NT NT CCR-US-IGS ND NT ND NT GWA-02S S S D S GWA-04S D S S GWA-OSS ND S r S GWA-36S T I NT D S U5-04S NT S NT NT U5-08S S S D D Deep Flow Zone CCR-US-01D ND NT NT CCR-U5-02D S D 5 NT CCR-US-03D S T D S CCR-U5-04D S S S S CCR-US-05D D S S CCR-US-06DA S D D D CCR-US-08D D D S CCR-US-10D ND D S GWA-02BRU S S GWA-03D S NE S S GWA-04D S S S S GWA-OSBRU S S D D GWA-31D S NT t GWA-36D D S S S US-04D ND NE US-05D S S D D US-O6D D S S S Wells Between Waste Boundary and Compliance Boundary Total Well ID Boron Lithium Sulfate Dissolved Solids Bedrock Flow Zone CCR-U5-04BR NE S S GWA-3113RAFSD D D U5-05BRD S S U5-08BRNE NE NE Wells Downgradient of the Source Area Near or Beyond Compliance Boundary Well ID or.. Lithium Sulfate Total Dissolved Solids Shallow Flow Zone GWA-34S ND NE GWA-35S S NE S S GWA-37S S S D S GWA-56S S JrWNT" S S MW-34S ND NE ND ND MW-36S S NE N D MW-38S S NT S S MW-40S S S Deep Flow Zone GWA-01BRU ND NT S S GWA-35D S NE D D GWA-37D S D GWA-56D ND S S S MW-34BRU ND NE S NT MW-36BRU ND NE D S MW-38D S S D D MW-40BRU I ND D Bedrock Flow Zone MW-38BR L S I S I D D Notes, 1. Summary of results and trends are presented for samples collected from 2015 - 2019. 2. Trend results are presented when at least four samples were available and frequency of detection was >50%. Statistically significant trends are reported at the 90% confidence level. 3. Variability Index (VI) is calculated as the (maximum - minimum) / median concentration and is calculated using detected concentrations only. Values less than 1 indicate low variability in the dataset. 4. For ph, statistically significant, increasing trend with a maximum recent result (2018 - 2019) less than the lower end of the standard range or greater than the upper end of the standard range. Maximum detected result for 2018 and 2019 time period shown in parentheses. 5. Wells that had insufficient samples collected (n<4) for all four consitituents were removed from table. See designation 'NE'. 4NE ND = Greater than 50 percent of constituent concentrations were non -detect p = Statistically significant, decreasing concentration trend 5 = Stable. No significant trend and variability is low (VI 5 1) = No significant trend and variability Is high (VI > 1) = Statistically significant, increasing concentration trend. = Insufficient number of samples to evaluate trend (n < 4) rep—d by: 1— Checked by: 1s TABLE 6-34 SEEP CORRECTIVE ACTION STRATEGY UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Seep ID Regulatory program General Location Approximate Average present Flow (cfs) Seep Corrective Action Strategy Corrective action at this location may consist of capturing and treating the seep or other remedial actions. Final corrective action plans for seeps that S-02 SOC North of U5 AB 0.1 are not dispositioned after completion of decanting will be proposed in an amendment to the CAP Update and submitted based on the schedule outlined in the SOC. Notes: cfs- cubic feet per second NPDES - National Pollution Discharge Elimination System SOC - Special Order by Consent Prepared by: SAS Checked by: TJG Page 1 of 1 TABLE 6-35 NPDES PERMIT LIMITS AND ANTICIPATED GROUNDWATER REMEDIATION PARAMETER LEVELS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC NPDES Outfalls Outfall 0021 Outfall 005 Maximum Detected Concentrations by Flow Zone Effluent Limitations and Monitoring Requirements Parameter Monthly Average Daily Maximum Monthly Average Daily Maximum Saprolite Transition Zone Bedrock Flow (MGD) INS 1 MGD INS INS NA NA NA Oil & Grease 15.0 mg/L 20.0 mg/L 15.0 mg/L 20.0 mg/L NA NA NA TSS 30.0 mg/L 50.0 mg/L 30.0 mg/L 50.0 mg/L 9.2 mg/L 12.7 mg/L 6 mg/L Total Chromium 0.2 mg/L 0.20 mg/L 0.2 mg/L 0.2 mg/L 0.003 mg/L 0.02 mg/L 0.002 mg/L Total Zinc 1.0 mg/L 1.0 mg/L 1.0 mg/L 1.0 mg/L 0.05 mg/L 0.25 mg/L 0.008 mg/L pH From 6.0 to 9.0 S.U. From 6.0 to 9.0 S.U. 3.7 - 6.4 S.U. 3.0 - 6.1 S.U. 6.4 - 6.9 S.U. Total Copper NA NA 251 ug/L 272 pg/L 9.6 pg/L 2.8 pg/L 0.72 Ng/L Chronic Toxicity NA NA Note 4 NA NA NA Total Iron3 NA NA 1.0 mg/L 1.0 mg/L 20.9 mg/L 23.4 mg/L 2.95 mg/L Total Residual Chlorine NA NA INS 28 pg/L NA NA NA 5-day BOD; 20' C NA NA 30.0 mg/L 45.0 mg/L NA NA NA Fecal Coliform (geo. Mean) NA NA 200/100 mL 400/100 mL NA NA NA Temperature NA NA INS 100° F NA NA NA Prepared by: VTV Checked by TJG Notes: 1 - Effective beginning on the commencement of the dewatering operation and lasting until permit expiration. 2 - Downgradient groundwater monitoring wells in area of groundwater remediation; Q1 2018 through Q2 2019 data. 3 - Monitoring shall be per occurrence of chemical metal cleaning and sample from a representative discharge. 4 - Chronic Toxicity (Ceriodaphnia) P/F at 3.14%; March, June, September, and December. MGD - million gallons per day NS - not specified NA - not analyzed TSS - total suspended solids S.U. - standard units BOD - biological oxygen demand mg/L - milligrams per liter pg - micrograms per liter mL - milliliters Page 1 of 1 TABLE 6-36 REMEDIAL TECHNOLOGY SCREENING SUMMARY UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale COIs pose no unacceptable risk to Monitored Natural Attenuation human health or the environment under (MNA) Yes conservative exposure scenarios. MNA could be implemented in conjunction with source control measures. In -Situ Technologies Low Permeability Barriers (LPB) No Technically challenging and costly. Mobile COIs are not the major concern. Groundwater Flushing No Modeling indicates that extraction will exert hydraulic control. Encapsulation No No area where COIs are concentrated. Permeable Reactive Barrier (PRB) Yes Potentially applicable for mitigation of low pH water. Groundwater Extraction Technologies Vertical Extraction Wells Yes Commonly used technology for groundwater extraction. Horizontal or Angular Extraction NO Modeling indicates that vertical Wells extraction wells are sufficient. A shallow trench could capture and Extraction Trenches Yes control of the acidic groundwater near the saddle dam. Hydraulic Fracturing No Not warranted based upon the limited extent of COIs in bedrock. Phytoremediation No Limited additional mass removal. Groundwater Treatment Technologies pH Adjustment Yes Retained for remedial alternatives that include groundwater extraction. Precipitation Yes Part of the treatment in the WWTP associated with Outfall 005. Ion Exchange No Expensive and not expected to be needed to meet discharge requirements. Membrane Filtration No Expensive and not expected to be needed to meet discharge requirements. Page 1 of 2 TABLE 6-36 REMEDIAL TECHNOLOGY SCREENING SUMMARY UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Summary of Remedial Retain Technology for Further Technology Screening Consideration Technology Yes/No Rationale Management of Extracted Groundwater Potential to discharge at Outfall 002 or NPDES Permitted Discharge Yes 005; must modify permit to include discharge of extracted groundwater Publicly Owned Treatment Works No Would require installation of (POTW) infrastructure; NPDES is a better option. Non -Discharge Permit/Infiltration NO Site soils have limited capacity to Gallery transmit water. Non -Discharge Permit/Land Will not be considered as long as disposal Application No via NPDES permitted outfall is a viable option. Beneficial Reuse Fire Protection No Limited application. Storage is problematic Non -Contact Cooling Water No Limited application. Dust Suppression and Truck Wash No Limited application. Prepared by: TJG Checked by:JEC Page 2 of 2 TABLE 6-37 REMEDIAL ALTERNATIVE 3 EXTRACTION WELL AND SOURCE CONTROL TRENCH SUMMARY UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Groundwater Extraction System Number of Wells Flow Zone Total Depth (ft bgs) 12 Saprolite/Transition Zone 98 - 122 1 (Source Control Trench) Saprolite 17 - 19 Total Extraction Well Count: 13 Groundwater extraction system flow and operation assumptions: Modeled groundwater extraction rate: 0.6 to 2.7 gpm per well; average 1.8 gpm per well. Estimated total system groundwater extraction rate: 21.6 gpm. Groundwater extraction wells operate to maintain water level near top of the submersible pump. Notes: ft bgs - feet below ground surface gpm - gallons per minute Prepared by: VTV Checked by: RAG Page 1 of 1 TABLE 6-38 ENVIRONMENTAL SUSTAINABILITY COMPARISONS FOR REMEDIATION ALTERNATIVES UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS LLC, MOORESBORO, NC Remedial Alternative Remedial Alternative 1 — Groundwater Remediation by MNA Remedial Alternative 2 — Groundwater Remediation by pH Adjustment Gallery Remedial Alternative 3 — Groundwater Remediation by Extraction Wells and Source Control Trench Emissions Units CO2 Emissions metric ton 1.14E+00 1.51 E+03 5.09E+02 Onsite NO, emissions metric ton 0.00E+00 2.50E-01 4.02E-01 Onsite SOx Emissions metric ton 0.00E+00 1.61 E-02 2.04E-02 Onsite PM10 Emissions metric ton 0.00E+00 1.25E-02 1.43E-02 Total NOx emissions metric ton 4.23E-04 3.78E+00 1.89E+00 Total SOx Emissions metric ton 1.49E-05 5.29E+00 1.18E+00 Total PM10 Emissions metric ton 8.58E-05 1.07E+00 2.47E-01 Total Energy Used MMBTU 1.44E+01 4.55E+05 4.48E+05 Total Emissions metric ton 1.14E+00 1.52E+03 5.12E+02 Notes: CO2 - Airborne emissions of carbon dioxide MMBTU - Million British Thermal Units NOx - Airborne emissions of nitrogen oxides (combination of nitrogen monoxide and nitrogen dioxide) SOx - Airborne emissions of sulfur oxides (combination of sulfur monoxide, sulfur dioxide, sulfur trioxide, and others) PMlo - Airborne emissions of particulate matter that is 10 micrometers or less in diameter Prepared by: GTC Checked by: SJB Page 1 of 1 TABLE 6-39 MODELED GROUNDWATER EXTRACTION WELL DETAILS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Well ID Easting Northing Approximate Ground Surface Elevation (feet) Operational DTW Maintained In Well (ft BGS) Well Depth (ft BGS) Targeted Flow Zones Total Simulated Flow (gpm) Vertical Extraction Wells EX-U5-1 1174126.90 545805.10 709 14 98 Saprolite/Transition Zone 2.5 EX-U5-2 1174180.80 545752.90 711 17 98 Saprolite/Transition Zone 2.5 EX-U5-3 1174241.40 545707.50 711 17 106 Saprolite/Transition Zone 2.7 EX-U5-4 1174000.70 545764.70 710 13 98 Saprolite/Transition Zone 2.4 EX-U5-5 1173854.20 545720.90 707 12 106 Saprolite/Transition Zone 2.4 EX-U5-6 1173945.10 545512.20 714 19 90 Saprolite/Transition Zone 0.6 EX-U5-7 1174014.10 545517.20 714 21 98 Saprolite/Transition Zone 1.1 EX-U5-8 1174093.30 545524.00 715 23 114 Saprolite/Transition Zone 1.8 EX-U5-9 1174201.00 545547.50 711 22 114 Saprolite/Transition Zone 2.0 EX-U5-10 1174148.80 545466.70 715 24 122 Saprolite/Transition Zone 0.7 EX-U5-11 1174249.80 545401.00 708 29 122 Saprolite/Transition Zone 1.4 EX-U5-12 1174259.90 545337.10 709 27 122 Saprolite/Transition Zone 1.4 Prepared by: GTC Checked by: RAG Notes: All depths are approximated and may change depending on site conditions. Flowrates are approximate and may change depending on site conditions. DTW - depth to water ft - feet ft BGS - feet below ground surface gpm - gallons per minute NA - Not applicable O TABLE 6-40 EFFECTIVENESS MONITORING PLAN ELEMENTS UNIT 5 INACTIVE ASH BASIN CORRECTIVE ACTION PLAN UPDATE CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Effectiveness Monitoring Plan (EMP) Post -Closure Monitoring Plan (PCMP) Implemented 30 days after CAP Approval Implemented after completion of ash basin closure activities EMP Groundwater Well Monitoring Network (background, downgradient of source areas) Performance Monitoring Network CCR-U5-6S GWA-36S GWA-3713R* CCR-U5-6DA GWA-36D MW-38S GWA-4S GWA-36BR* MW-38D GWA-4D GWA-37S MW-38BR GWA-4BR* GWA-37D Continued Monitoring Network CCR-U5-3S GWA-2S GWA-35D CCR-U5-3D GWA-26RU GWA-35BR* CCR-U5-4S GWA-2BRA GWA-67BR CCR-U5-4D GWA-3D MW-36S CCR-U5-4BR GWA-3BR* MW-36BRU CCR-U5-5D GWA-35S MW-36BR* Background Monitoring Wells' GWA-30S MW-30DA MW-32D GWA-30BR MW-32S MW-32BR MW-30S PCMP Groundwater Well Monitoring Network (background, downgradient of source areas) A PCMP will be implemented at the Site in accordance with G.S. 130A-309.214(a)(4)k.2 after completion of ash basin closure activities. EMP Groundwater Quality"' PCMP Groundwater Quality (Semi -Annual Sampling Frequency) (Sampling frequency to be determined) Alkalinity Cobalt2 Potassium Aluminum Ferrous Iron Sodium Bicarbonate Alkalinity Iron Strontium2 z z 2 Parameters and sampling frequency to be included in the PCMP in Boron Lithium Sulfate accordance with G.S. 130A-309.214(a)(4)k.2 when submitted. Calcium Magnesium Total Dissolved Solids2 Chromium (Total)2 Manganese2 Total Organic Carbon Chromium (VI)2 Nitrate + Nitrite Total Radium2 CMP and PCMP Groundwater Field Parameters Water Level Specific Conductivity Temperature pH Oxidation Reduction Potential Dissolved Oxygen EMP Review 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation of compliance with applicable Standards 4) Evaluation of system performance and effectiveness 4) Recommend plan adjustments, if applicable, to optimize the remedial action 5-Year Performance Review Reporting 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Re-evaluate effectiveness of technology 4) Verify modeling results, update model if needed 5) Modify corrective action approach, as needed, to achieve 30 days after CAP approval, the EMP will be implemented at the Site and will continue until there is a total of three years of data confirming COIs are below applicable Standards at or beyond the compliance boundary, at which time a request for completion of active remediation will be filed with NCDEQ. If applicable standards are not met, the EMP will continue and transition to post -closure monitoring if necessary. PCMP Review Annual Evaluation and Reporting_ 1) Summary of annual groundwater monitoring results 2) Evaluate statistical concentration trends 2) Comparison of observed concentrations to model predictions 3) Evaluation 02L compliance 4) Recommend plan adjustments, if applicable At a frequency no greater than 5 years: 1) Update background analysis 2) Confirm Risk Assessment assumptions remain valid 3) Verify model results, update if needed PCMP Duration After ash basin closure and following ash basin closure certification, a PCMP will be implemented at the Site for a minimum of 30 years in accordance with G. S. 130A-309.214(4)(k)(2). Early termination: If groundwater monitoring results are below applicable Standards at the compliance boundary for three years, Duke Energy will request completion of corrective action in accordance with G.S. 130A- 309.214(a)(3)b. If groundwater monitoring results are above applicable Standards, the PCMP will continue. Prepared by: TJG Checked by: SAS ' Approved background groundwater monitoring locations ' Corrective action COIs to monitor plume stability and physical attenuation either from active remedy or natural dilution/dispersion 3 The number of monitoring wells and parameters may be adjusted based on additional data and the effects of corrective action. 4 Groundwater standards may be modified over time in accordance with 02L .0106(k) * Proposed new well Italicized parameters - parameters for general water quality to evaluate monitoring data quality Wells indicated in red will have geochemical sondes placed to monitor geochemical conditions 05M