Cumberland Fossil Fossil Plant Plant CUMBERLAND CITY,CITY, TENNESSEETENNESSEE

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EPA CCR RULERule Groundwater GROUNDWATER Monitoring MONITORING Commissioning Date: 1973 This fact sheet summarizes groundwater monitoring conducted by Commissioning Date: 1973 This fact sheet summarizes groundwater monitoring conducted by TVA for the Output: 2,470 Megawatts TVACumberland as required Fossil Plant,by the as U.S. required Environmental by the U.S. Environmental Protection ProtectionAgency (EPA) Agency (16Output: billion 2,470 kilowatt-hours) Megawatts (16 billion (EPA) CoalCombustion Combustion Residuals Residuals (CCR)(CCR) Rule.Rule. The The EPA EPA published published the CCR the Rule kilowatt-hours) on April 17, 2015. It requires companies operating coal-fired power plants to study Number of homes powered: CCR Rule on April 17, 2015. It requires companies operating coal- 1.1 MillionNumber of homes powered: whether constituents in CCR have been released to groundwater from active, fired power plants to study whether constituents in CCR have been 1.1 Million inactive and new CCR impoundments, as well as active and new CCR landfills. Wet to Dry / Dewatered released to groundwater. This fact sheet addresses the EPA CCR ConversionWet to Dry /Program: Dewatered Activities RuleThe CCR groundwater Rule establishes monitoring multiple phasesonly. of protective groundwater monitoring underwayConversion Program: Complete including baseline sampling, Detection Monitoring and Assessment Monitoring. for fly ash and gypsum. Bottom ash InCorrective addition action to ongoing may be necessary groundwater at the monitoringcompletion of required this process. under For more TVAdewatering Wide CCR tank-based Conversion solution Program Total Spend: information on the CCR Rule Groundwater Monitoring requirements, go to scheduled for 2019 State regulations, TVA enhanced the monitoring well network at the Approximately $1.3 Billion www.tva.com/ccr. Cumberland Fossil Plant to comply with the CCR Rule requirements. TVA Wide CCR Conversion Additional wells were installed around the CCR management units Program Total Spend: Cumberland Plant CCR Rule Groundwater Monitoring Network as needed and TVA implemented a baseline sampling program. After Approximately $1.3 Billion In addition to ongoing groundwater monitoring required under State regulations, completionTVA installed additionalof the baseline wells around sampling, the CCR the management CCR Rule units, requires as needed, TVA toand begin TVA implemented monitoring a groundwater baseline sampling in a program. step that After is completioncalled “Detection of baseline Monitoring”.sampling, TVA beganThe constituents Detection Monitoring. specified The constituentsby the CCR specified Rule for byDetection the CCR Monitoring are boron, calcium, chloride,Rule for Detection fluoride, Monitoring pH, sulfate, are boron, and calcium, total dissolved chloride, fluoride,solids (TDS). pH, sulfate, These seven constituents occur naturally inand soils, total dissolvedrock, groundwater solids (TDS). andThese surface seven constituents water, and can they occur are naturally also present in coal and in CCR. They were in soils, rock, groundwater and surface water, and can also be present in coal selected by EPA because they can indicate groundwater conditions that may require further evaluation. and CCR. They were selected by EPA because they can indicate groundwater EPAconditions CCR that RULE may requireGROUNDWATER further evaluation. MONITORING NETWORK FOR THE CUMBERLAND FOSSIL PLANT TVA installed “background wells” in locations that are not expected to be affected by the management of CCR. Other wells were drilled around the edge of the areas where CCR is managed or were already existing and being monitored. These wells are sometimes referred to as “downgradient wells” and placed in locations to monitor for releases to groundwater. The locations of the wells are shown below.

TENNESSEE VALLEY AUTHORITY | FACT SHEET CCR GROUNDWATER MONITORING VALLEY AUTHORITY | FACT SHEET AUGUST 13, 2019 CCR GROUNDWATER MONITORING TVA installed “background”, or upgradient, wells in locations that are not expected to be affected by the management of CCR. Other wells were drilled around the edge of the areas where CCR is managed or already ($existed¯$ and were being monitored. These wells are sometimes referred to as “downgradient wells” and placed in locations to monitor for releases to groundwater. The locations of the wells are shown below.

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Stilling Pond (!CUF-208 Ash Pond (Retention Pond)

CUF-209 CUF-206 CUF-205 (! Dry Ash Stack (!

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Disc laimer: Stantec assumes no responsibility for data supplied in electo ronic format. The recipient acc epts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its of ficers, em ployees, c onsultants and agents, from any and all claim s arising in any way from the c ontent or provision of the data. U r IN ! 0 1,000 2,000 g ( Background Well Cumberland City Prepared by WSW on 2018-01-30 k IL WV c Feet

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i CCR Rule Detection Monitoring Results for Cumberland Fossil Plant Tennessee Independent Review by JK on 2018-01-30 KY 1:24,000 (At original document size of 8.5x11) n (! Downgradient Well U R MO Client/Project C VA Notes C Tennessee Valley Authority _ w !( 1. Coordinate System: NAD 1983 StatePlane Tennessee FIPS 4100 Feet 1 g i CCR Unit Subject to CCR Rule 2. Imagery Source: Tucker Mapping Solutions, INC (Flown April 8, 2017) Cumberland Fossil Plant

_ F TVA prepared its initial 2017 Annual Groundwater Monitoring and Corrective Action Reports for the Cumberland Fossil 1 F

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C Plant, which analyzed the Detection Monitoring results to determine if there were statistically significant increases (SSIs) over \ s 1 d x

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: www.tva.com/ccr. The initial comparison of downgradient wells to upgradient wells showed that concentrations of boron, Disc laimer: Stantec assumes no responsibility for data supplied in electronic format. The recipient acc epts full responsibility for verifying the accuracy and completeness of the data. The recipient releases Stantec, its of ficers, em ployees, c onsultants and agents, from any and all claim s arising in any way from the c ontent or provision of the data. U calcium, chloride, sulfate and TDS around the CCR management units may be greater than naturally occurring levels. Data does not reflect the quality of public drinking water supplies, which are regularly tested to confirm they are meeting safe drinking water standards.

2018 Groundwater Monitoring Activities Since the initial groundwater monitoring results identified SSIs, TVA conducted alternate source demonstrations to determine if the exceedances were the result of another source or the result of an error in the sampling or analytical method, or natural variability in groundwater quality. No alternate source was determined resulting in the facility moving into the Assessment Monitoring phase. The groundwater sampling for this phase is expanded to test for additional constituents, for which TVA has determined groundwater protection standards (GWPS), including , , barium, , , , , fluoride, , lithium, , molybdenum, radium, and .

TENNESSEE VALLEY AUTHORITY | FACT SHEET AUGUST 13, 2019 CCR GROUNDWATER MONITORING Cumberland Fossil Plant CCR Rule Assessment Monitoring Results

The Assessment Monitoring results are contained in the 2018 Annual Groundwater Monitoring and Corrective Action Reports. The reports can be found at www.tva.com/ccr. Below is the Cumberland Assessment Monitoring Results Matrix, which is based on comparative analysis of statistical analysis results versus GWPS. Refer to Appendix A – Statistical Analysis Report of the 2018 Annual Groundwater Monitoring and Corrective Actions Reports for more information.

GROUNDWATER QUALITY MONITORING WELL LOCATIONS Background Dry Ash Stack and Gypsum Storage Area Stilling and Retention Pond Wells GWPS CUF- CUF- CUF- CUF- CUF- CUF- CUF- CUF- CUF- 93-2R 93-3 Constituent mg/L 201 202 209 211 212 205 206 207 208 Antimony 0.006 Arsenic 0.01 Barium 2 Beryllium 0.004 Cadmium 0.005 Chromium 0.1 Cobalt 0.006 Fluoride 4 Lead 0.015 Lithium 0.04 Mercury 0.002 Molybdenum 0.1 Rad226+228 5 pCi/L Selenium 0.05 Thallium 0.002

Color Coding Key

Monitoring data results are below GWPS Monitoring data results are below GWPS, but results are 65% or more of the GWPS Monitoring data results exceed GWPS (TVA will initiate assessment of corrective measure)

Next Steps for Cumberland Fossil Plant CCR Rule Groundwater Monitoring TVA will continue to monitor and evaluate the groundwater at the Cumberland Fossil Plant site. In January 2019, TVA completed an evaluation of whether there were exceedances of GWPS detected at the Bottom Ash Pond, Dry Ash Stack, Gypsum Storage Area (which has a multi-unit groundwater monitoring well network) and the Stilling Pond (including Retention Pond). During assessment monitoring, three SSLs of Appendix IV constituents were reported above GWPS in downgradient monitoring wells. TVA has since completed an Assessment of Corrective Measures Report to analyze the potential effectiveness of potential corrective measures. This report will be posted to the CCR website on August 14, 2019. A semiannual report describing the progress in selecting and designing the final remedy will be completed in January 2020.

TENNESSEE VALLEY AUTHORITY | FACT SHEET AUGUST 13, 2019 CCR GROUNDWATER MONITORING