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Home My WebLink AboutMRO Technical Direction and Action Items 9-1-17Water Resources Environmental Quality September 1, 2017 Ed Sullivan Duke Energy 526 South Church Street Mail Code EC 13K Charlotte, North Carolina 28202 ROY COOPER Governor MICHAEL S. REGAN Secretary S. JAY ZIMMERMAN Director Subject: Technical Direction and Action Items, Mooresville Regional Office Meeting - June 15,2017 Dear Mr. Sullivan: On July 13, 2017, the North Carolina Department of Environmental Quality's Division of Water Resources (Division) received the meeting minutes from the June 15, 2017 Mooresville Regional Office (MRO) Meeting. As part of the process agreed upon to facilitate completion of the site assessments and corrective action plans, the Division provides the following summary of technical direction and action items discussed during the meeting: Program -wide Issues o As monitoring wells are installed, reinstalled or abandoned, the interim groundwater monitoring plan for each facility should immediately incorporate those additions, deletions or replacements. Any well installation or abandonment should be communicated to the appropriate regional staff. o Porewater wells should continue to be sampled as part of the interim groundwater monitoring plan until communicated otherwise by the Division. o If monitored natural attenuation (MNA) is proposed for use at a coal ash facility subject to CAMA ruling, it will need to be demonstrated that natural attenuation will NOT affect future groundwater users (i.e., specifically downgradient vacant properties that currently do not have well or water connection). This is not stated in CAMA, but is required as defined in the 15A NCAC 02L .0106 (1)(4). Background Statistics o For chromium in soils, Duke Energy should use the hexavalent chromium IHSB PSRG for Protection of Groundwater for compliance (3.8 mg/kg). o Soil samples collected within fill material are not acceptable for use in background determinations. o Soil samples collected within approximately 1 foot of the water table are not acceptable for use in background determinations. State of North Carolina I Environmental Quality I Division of Water Resources Water Quality Regional operations Section 1636 Mail Service Center I Raleigh, North Carolina 27699-1636 919-707-9129 • Action Items o Plant Allen ■ Wells to be redeveloped prior to next sampling event: BG-4D, AB-12S, AB-14D, AB-22S, AB-2213R, A13-27D, A13-30S, AB-33D, GWA-3D, GWA-21BF, GWA-22S, GWA-26D, and GWA-9 ■ Wells to be monitored for potential redevelopment (due to fluctuating pH or other water quality issues): GWA-18D, GWA-26D, AB-21BRL, and AB-27BR ■ Wells to be installed or replaced (as soon as possible): GWA-6BRA, GWA-24SA, and AB-24BRL ■ As part of the interim groundwater monitoring plan for the facility, only boron, sulfate, and water levels should be monitored at the following locations: AB-21D, A13-24D, AB-25BRU, AB-2513R, A13-35D, GWA- 19D, and GWA-23D ■ Duke Energy should confirm pond elevation used for comparison to water levels observed at the AB-4 well cluster. Additional justification is needed before approving location suitable as background location. • BG-ID, 13G-213R, and GWA-21D were replaced in May 2017 and analytical data will need to be reevaluated (approximately 3 to 4 rounds of data) for use in background determinations at the site. ■ Two additional surface water samples collected from edge of bank are needed upgradient and downgradient of the site (beyond site activities). ■ Details regarding review of background soil and groundwater statistical methodology was documented in a letter to Duke Energy on July 7, 2017. Please refer to this document for all comments regarding background determinations. o Buck Steam Station ■ Wells to be redeveloped prior to next sampling event: AB-4SL, A13-9S, GWA-1D, GWA-10D, GWA-13D, GWA-19D, MW-11D, and MW- 613R ■ Well(s) to be monitored for potential redevelopment (due to fluctuating pH or other water quality issues): A134BRL ■ Wells to be installed or replaced (as soon as possible): AB-IOBRL, GWA-613RL, GWA-1513R, and MW-1113RL ■ As part of the interim groundwater monitoring plan for the facility, only boron, sulfate, and water levels should be monitored at the following locations: AB-213R and GWA-14D ■ BG-ID, BG-113R, and MW-813R were replaced in April/May 2017 and analytical data will need to be reevaluated (approximately 3 to 4 rounds of data) for use in background determinations at the site. ■ GWA-16S/D/BR was recently installed and analytical data will need to be further evaluated (approximately 3-4 rounds of data) for use in background determinations at the site. ■ Surface water samples currently being collected from mid -stream of the Yadkin River should be taken from approximately the same location along the edge of bank. Duke Energy should confirm the upgradient location is beyond site activities. Details regarding review of background soil and groundwater statistical methodology was documented in a letter to Duke Energy on July 7, 2017. Please refer to this document for all comments regarding background determinations. o Marshall Steam Station ■ Wells to be redeveloped prior to the next sampling event: AB-20D, BG- 3S, and GWA-13DA ■ Wells to be monitored for potential redevelopment (due to fluctuating pH or other water quality issues): AL-2BRL, BG-3S, and BG-3D ■ Wells to be installed (as soon as possible): AB- 1BRL, AL-2BRLL, and AL-4BRL ■ As part of the interim groundwater monitoring plan for the facility, only boron, sulfate, and water levels should be monitored at the following locations: GWA-12D and GWA-13DA ■ BG-1BRA was recently replaced and analytical data will need to be further evaluated (approximately 3 to 4 rounds of data) for use in background determinations at the site. ■ One additional surface water sample should be collected immediately downgradient of GWA-11 and GWA-15 to evaluate boron exceedances observed at these locations. ■ Details regarding review of background soil and groundwater statistical methodology was documented in a letter to Duke Energy on July 7, 2017. Please refer to this document for all comments regarding background determinations. If you have any questions, please feel free to contact Brandy Costner (Mooresville Regional Office) at (704)-663-1699 or Steve Lanter (Central Office) at (919) 807-6444. Sincerely, a,j, Jon Risgaard, Section Chief Water Quality Regional Operations Section Division of Water Resources cc: MRO WQROS Regional Office Supervisor WQROS Central Office Copy