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Home My WebLink AboutNC0005088_Gypsum Stack-Out Area Assessment Tech Memo_20180719TECHNICAL MEMORANDUM P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\Gypsum Stack-Out Area Assessment Tech Memo - Cliffside.docx Date: June 29, 2018 File: 1026.21.06P To: Ryan Czop (Duke Energy) Cc: Kathy Webb (SynTerra) From: Scott Spinner Subject: Soil and Groundwater Assessment – Gypsum Stack-Out Area – Cliffside Steam Station Duke Energy Carolinas, LLC (Duke Energy) owns and operates the Rogers Energy Complex (henceforth referred to as the Cliffside Steam Station (CSS), or the site), which is located in Mooresboro, Rutherford and Cleveland Counties, North Carolina. CSS began operation in 1940 as a coal-fired generating station. Units 1 through 4 were retired in October 2011, and currently only Units 5 and 6 are in operation at CSS. Gypsum produced by the flue gas desulfurization (FGD) process at Units 5 and 6 is temporarily stored on approximately 5 acres northeast of the the Unit 6 power gerneration plant prior to disposal in the Cliffside CCP Landfill or for offsite beneficial reuse. Groundwater and soil assessment activities for the gypsum stack-out area are described herein. Regulatory Background In 2014, The North Carolina General Assembly passed the Coal Ash Management Act (CAMA). CAMA required owners of a coal combustion residuals (CCR) surface impoundment to conduct detailed assessment of site groundwater within and around the CCR surface impoundment. Groundwater monitoring wells were not installed to assess the gypsum stack-out area during CAMA-associated fieldwork. Duke Energy understands the soils beneath the gypsum stack-out area may be a potential “secondary source” of inorganic constituents that will be assessed apart from CAMA. Soil and Groundwater Assessment – Gypsum Stack-Out Area June 29, 2018 Cliffside Steam Station Page 2 of 3 P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\Gypsum Stack-Out Area Assessment Tech Memo - Cliffside.docx Station Description Coal-fired power generation operations began at CSS in 1940. Coal is transported on- site by rail and offloaded onto the coal pile area where it is stored until burned by the coal-powered energy generating units. Gypsum produced by the FGD process is temporarily stored on the gypsum stack-out area which is approximately 5 acres and is located northeast of the the Unit 6 power generation plant. The southern approximately 1.3 acres of the gypsum stack-out area is underlain by a liner system, and a majority of the stack-out area is covered with a shelter. The topography at CSS generally slopes downward from the south to the Broad River on the north. The site layout is shown on Figure 1. Gypsum Stack-Out Area Assessment Objectives Objectives of the gypsum stack-out area assessment include the following: Characterize inorganic constituents associated with gypsum stack-out area soils Characterize inorganic constituent concentrations in groundwater underlying the gypsum stack out area perimeter Compare inorganic constituent concentrations in gypsum stack-out area groundwater and site background groundwater Soil Assessment Gypsum stack-out area soils are proposed to be sampled and analyzed for inorganic parameters to determine if the soil may be a secondary source of gypsum stack-out area constituents that may leach into underlying groundwater. Soil samples are proposed to be collected at proposed monitoring well locations (GP-1 through GP-4) as part of well installation activities (Figure 1). Due to the gypsum stack-out area being active, soil samples directly beneath the footprint of the stack-out area will not be accessible. Soil samples will be collected at approximately 5-foot intervals to the top of the groundwater table. An additional shallow soil sample will be collected below the water table within the new well screened intervals. Samples of bedrock will not be collected for analysis. Soil samples will be analyzed for inorganic parameters as listed on Table 1. Soil samples will also be collected approximately 5-feet below ground surface and the interval immediately above the water table and analyzed for leachable inorganics using Synthetic Precipitation Leaching Procedures (SPLP) at each well cluster location. Groundwater Assessment Ten gypsum stack-out area assessment (GP) groundwater monitoring wells are proposed to be installed to characterize groundwater. Four shallow (“S”), four deep Soil and Groundwater Assessment – Gypsum Stack-Out Area June 29, 2018 Cliffside Steam Station Page 3 of 3 P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\Gypsum Stack-Out Area Assessment Tech Memo - Cliffside.docx (“D”), and two bedrock (“BR”) groundwater monitoring wells (GP-1S/D, GP-2S/D/BR, GP-3S/D, and CP-4S/D/BR) are proposed to be installed. Proposed approximate GP well installation locations are shown on Figure 1 and proposed well details are provided as Table 2. Shallow groundwater monitoring wells will be installed approximately 5 feet below the water table. Specific well locations may be shifted depending upon access and field conditions at the time of installation. Groundwater samples will be analyzed for inorganic constituents as listed on Table 3. Groundwater samples from monitoring wells GP-1S/D and GP-2S/D/BR will also be analyzed for total uranium, radium-226, and radium-228. Gypsum Stack-Out Area Assessment Report A gypsum stack-out area assessment report will be prepared once all soil and groundwater sample analytical data is received following two rounds of groundwater data collection. Additional existing site data will be used in characterizing gypsum stack-out area soils and groundwater, including CAMA and CCR program data. The report will include the following components: 1) Site History and Source Characterization 2) Site Geology and Hydrogeology 3) Sampling Results 4) Site Conceptual Model 5) Conclusions and Recommendations ATTACHMENTS: Table 1: Soil Analytical Methods Table 2: Proposed Gypsum Stack-Out Area Assessment Soil Samples and Monitoring Wells Table 3: Groundwater Analytical Methods Figure 1: Proposed Gypsum Stack-Out Area Assessment Monitoring Well Locations Soil and Groundwater Assessment – Gypsum Stack-Out Area June 1, 2018 Cliffside Steam Station P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\Gypsum Stack-Out Area Assessment Tech Memo - Cliffside.docx ATTACHMENTS TABLE 1 SOIL ANALYTICAL METHODS CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC INORGANIC COMPOUNDS UNITS METHOD Aluminum mg/kg EPA 6010D Antimony mg/kg EPA 6020B Arsenic mg/kg EPA 6020A Barium mg/kg EPA 6010C Beryllium mg/kg EPA 6020B Boron mg/kg EPA 6010C Cadmium mg/kg EPA 6020A Calcium mg/kg EPA 6010C Chloride mg/kg EPA 9056A Chromium mg/kg EPA 6010C Cobalt mg/kg EPA 6020A Copper mg/kg EPA 6010C Iron mg/kg EPA 6010C Lead mg/kg EPA 6020A Magnesium mg/kg EPA 6010C Manganese mg/kg EPA 6010C Mercury mg/kg EPA Method 7471B Molybdenum mg/kg EPA 6010C Nickel mg/kg EPA 6010C Nitrate as Nitrogen mg/kg EPA 9056A pH SU EPA 9045D Potassium mg/kg EPA 6010C Selenium mg/kg EPA 6020A Sodium mg/kg EPA 6010C Strontium mg/kg EPA 6010C Sulfate mg/kg EPA 9056A Thallium (low level) (SPLP Extract only)mg/kg EPA 6020A Total Organic Carbon mg/kg EPA 9060 Vanadium mg/kg EPA 6020A Zinc mg/kg EPA 6010C Notes: meq/100g - millequivalents per 100 grams mg/kg - Milligrams per kilogram mV - Millivolts S.U. - Standard Unit Prepared by: RBI Checked by: SRW/TCP 1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045; select soil samples will also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods 6010/6020. 2. Analytical methods and reporting limits as presented were applicable at time of CSA field implementation in 2015. Analytical methods and reporting limits are updated periodically and applied as appropriate. P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\ Table 1 Soil Analytical Methods Page 1 of 1 TABLE 2 PROPOSED GYPSUM STACK-OUT AREA SOIL SAMPLES AND MONITORING WELLS CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC Monitoring Well ID Estimated Well Depth (feet bgs) Soil Sample ID (Estimated Depth Interval in feet bgs) Comments ----GP-1SB (3.5-5)Near-surface unsaturated soil sample (water table ~25 feet bgs) ----GP-1SB (8.5-10)Unsaturated soil sample ----GP-1SB (13.5-15)Unsaturated soil sample ----GP-1SB (18.5-20)Unsaturated soil sample ----GP-1SB (23.5-25)Unsaturated soil sample GP-1S 40 GP-1SB (33.5-35)Soil sample from shallow well screened interval GP-1D 60 GP-1SB (53.5-55)Soil sample from deep well screened interval ----GP-2SB (3.5-5)Near-surface unsaturated soil sample (water table ~25 feet bgs) ----GP-2SB (8.5-10)Unsaturated soil sample ----GP-2SB (13.5-15)Unsaturated soil sample ----GP-2SB (18.5-20)Unsaturated soil sample ----GP-2SB (23.5-25)Unsaturated soil sample CP-2S 40 GP-2SB (33.5-35)Soil sample from shallow well screened interval CP-2D 60 GP-2SB (53.5-55)Soil sample from deep well screened interval CP-2BR 130 -No soil samples from this well ----GP-3SB (3.5-5)Near-surface unsaturated soil sample (water table ~25 feet bgs) ----GP-3SB (8.5-10)Unsaturated soil sample ----GP-SB (13.5-15)Unsaturated soil sample ----GP-3SB (18.5-20)Unsaturated soil sample ----GP-3SB (23.5-25)Unsaturated soil sample CP-3S 40 GP-3SB (33.5-35)Soil sample from shallow well screened interval CP-3D 60 GP-3SB (53.5-55)Soil sample from deep well screened interval ----GP-4SB (3.5-5)Near-surface unsaturated soil sample (water table ~25 feet bgs) ----GP-4SB (8.5-10)Unsaturated soil sample ----GP-4SB (13.5-15)Unsaturated soil sample ----GP-4SB (18.5-20)Unsaturated soil sample ----GP-4SB (23.5-25)Unsaturated soil sample CP-4S 40 GP-4SB (33.5-35)Soil sample from shallow well screened interval CP-4D 60 GP-4SB (53.5-55)Soil sample from deep well screened interval CP-4BR 130 -No soil samples from this well Prepared by: SAS Checked by: DMY Notes: bgs = below ground surface ~ = Approximately SynTerra recommends hollow stem auger and air rotary drilling methods for boring and well installation. Continuous cores from air rotary drilling provide sufficient material for soil sampling and lithologic description. Estimated well and soil sample depths based on data from the GWA-14 and GWA-38 well clusters. Number of soil samples shown is approximate. A shallower water table will result in fewer samples, and a deeper water table will result in additional samples. SynTerra recommends each shallow well screen be installed approximately 5 feet beneath the water table and have a length of at least 10 feet. P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\Table 2 - CSS Proposed Gypsum Assessment Boring & Well Depths Page 1 of 1 TABLE 3 GROUNDWATER ANALYTICAL METHODS CLIFFSIDE STEAM STATION DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC PARAMETER RL UNITS METHOD pH NA SU Field Water Quality Meter Specific Conductance NA µS/cm Field Water Quality Meter Temperature NA ºC Field Water Quality Meter Dissolved Oxygen NA mg/L Field Water Quality Meter Oxidation Reduction Potential NA mV Field Water Quality Meter Eh NA mV Field Water Quality Meter Turbidity NA NTU Field Water Quality Meter Aluminum 0.005 mg/L EPA 200.7 or 6010D Antimony 0.001 mg/L EPA 200.8 or 6020B Arsenic 0.001 mg/L EPA 200.8 or 6020B Barium 0.005 mg/L EPA 200.7 or 6010D Beryllium 0.001 mg/L EPA 200.8 or 6020B Boron 0.05 mg/L EPA 200.7 or 6010D Cadmium 0.001 mg/L EPA 200.8 or 6020B Chromium 0.001 mg/L EPA 200.8 or 6020B Cobalt 0.001 mg/L EPA 200.8 or 6020B Copper 0.001 mg/L EPA 200.8 or 6020B Hexavalent Chromium 0.000025 mg/L EPA 218.7 Iron 0.01 mg/L EPA 200.7 or 6010D Lithium 1 mg/L EPA 200.7 or 6010D Lead 0.001 mg/L EPA 200.8 or 6020B Manganese 0.005 mg/L EPA 200.7 or 6010D Mercury 0.00005 mg/L EPA 245.1 or 7470A Molybdenum 0.001 mg/L EPA 200.8 or 6020B Nickel 0.001 mg/L EPA 200.8 or 6020B Selenium 0.001 mg/L EPA 200.8 or 6020B Strontium 0.005 mg/L EPA 200.7 or 6010D Thallium (low level)0.0002 mg/L EPA 200.8 or 6020B Vanadium (low level)0.0003 mg/L EPA 200.8 or 6020B Zinc 0.005 mg/L EPA 200.7 or 6010D Radium 226 1 pCi/L EPA 903.1 Modified Radium 228 1 pCi/L EPA 904.0/SW846 9320 Modified Uranium (233, 234, 236, 238)Varies by isotope µg/mL SW846 3010A/6020A Alkalinity (as CaCO3)5 mg/L SM 2320B Bicarbonate 5 mg/L SM 2320B Calcium 0.01 mg/L EPA 200.7 Carbonate 5 mg/L SM 2320B Chloride 0.1 mg/L EPA 300.0 or 9056A Fluoride 0.1 mg/L EPA 300.0 or 9056A Magnesium 0.005 mg/L EPA 200.7 or 6010D Potassium 0.1 mg/L EPA 200.7 Sodium 0.05 mg/L EPA 200.7 Sulfate 0.1 mg/L EPA 300.0 or 9056A Sulfide 0.1 mg/L SM 4500 S2 D Total Dissolved Solids 25 mg/L SM 2540C Total Phosphorus 0.05 mg/L EPA 365.1 Total Organic Carbon 0.1 mg/L SM5310C/EPA9060A Total Suspended Solids 5 mg/L SM 2450D Prepared by: HHS Checked by: RHJ Notes: NA indicates not applicable. °C - Degrees Celsius mg/L - Milligrams per liter mV - Millivolts NTU - Nephelometric turbidity unit pCi/L - picocuries per liter RL = reporting limit S.U. - Standard Unit ug/mL - micrograms per milliliter µS/cm = micro-Siemens per centimeter Dissolved and total metals analysis FIELD PARAMETERS INORGANICS RADIONUCLIDES ANIONS/CATIONS/OTHER P:\Duke Energy Carolinas\21. CLIFFSIDE\06.EHS-CAMA Compliance Support and Corrective Action\Assessment\Gypsum Stack-Out Area Assessment\Gypsum Stack-Out Area Assessment Workplan\ Table 3 - Groundwater Analytical Methods Page 1 of 1 &<&< &< &<&< &<&< &<&< &<&< &< &<&< &< &<&<&< &<&< &<&< &< &< &<&< &<&<&< &<&< &<&<&<&<&< &<&< &<&< &< &<&< !( !( !( !( !( GWA-31BRA GWA-14BR IB-4S-SL GWA-20BR AB-2BRO GWA-20D GWA-20S GWA-31D AB-2D AB-2S GWA-4D GWA-4S GWA-5BRU GWA-5S GWA-13BR GWA-14D GWA-14S GWA-31BR GWA-33BR GWA-33D GWA-33S GWA-36D GWA-36S GWA-38D GWA-38S GWA-39S GWA-42S GWA-43DGWA-43S GWA-44BR GWA-44D GWA-44S IB-4BR IB-4D MW-8D MW-8S MW-23D MW-23DR MW-23S MW-40BRU MW-40S U5-6D U5-6S GP-1S/D GP-2S/D/BR GP-3S/D GP-4S/D/BR FIGURE 1PROPOSED ADDITIONAL ASSESSMENTMONITORING WELLS - GYPSUM STACK-OUT AREACLIFFSIDE STEAM STATIONDUKE ENERGY CAROLINAS, LLCMOORESBORO, NORTH CAROLINADRAWN BY: A. ROBINSONPROJECT MANAGER: S. SPINNERCHECKED BY: M. YOUNGBLOOD DATE: 03/05/2018 148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE 864-421-9999www.synterracorp.com P:\Duke Energy Progress.1026\00 GIS BASE DATA\Cliffside\Mapdocs\MISC\CLIFFSIDE_Proposed_Assessment_Gypsum Stack.mxd 100 0 100 20050 GRAPHIC SCALE IN FEET UNITS 1-4INACTIVEASH BASIN LEGEND !(PROPOSED GYPSUM STACK-OUT AREAASSESSMENT MONITORING WELL LOCATION &<EXISTING MONITORING WELL LOCATION &<EXISTING MONITORING WELL LOCATION(ABANDONED) WETLAND FROM AMEC NRTR T&E SPECIES FROM AMEC NRTR TRANSMISSION LINES FROM WSP SURVEY RAILROAD TRACKS FROM WSP SURVEY ASH BASIN WASTE BOUNDARY INACTIVE ASH BASIN WASTE BOUNDARY ASH BASIN COMPLIANCE BOUNDARY NOTES: 1) IT IS HEREIN NOTED THAT DUKE ENERGY IS NOT WAIVING THE RIGHT TO A COMPLIANCE BOUNDARY(S) TO THE FULL EXTENT SET OUT IN THE LAW OR ATTEMPT TO IMPAIR THE DEPARTMENT'S ABILITY TO CHANGE THE COMPLIANCE BOUNDARY(S) IN THE FUTURE, IF CIRCUMSTANCES W ARRANT. 2) AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO AND IS DATED OCTOBER 8, 2016. UNIT 6 GYPSUM STACK-OUTAREA