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HomeMy WebLinkAboutNCS000572_Dan River Application Add Info Letter_20140826NCDENR North Carolina Department of Environment and Natural Resources Pat McCrory John E. Skvarla, III Governor Secretary August 26, 2014 Mr. Harry Sideris, Senior Vice President, Environmental Health & Safety Duke Energy 526 South Street Charlotte, NC 28202 Subject: NPDES Stormwater Permit Application Additional Information Request Dan River Combined Cycle Station Rockingham County Dear Mr. Sideris: The Division of Energy, Mineral, and Land Resources' Stormwater Permitting Program (SPP) received an application for an NPDES stormwater permit for this facility on August 1, 2014. We need additional information from Duke Energy Carolinas, LLC ("Duke") to continue processing that application and developing a draft permit. Analytical sampling results were provided for stormwater discharges from a July 15, 2014 rain event. The ten sample locations included eight stormwater discharge points (SW001, 003, 004, 005, 006, 007, 008, and 010), plus roof drainage from the powerhouse building (apparently not a stormwater discharge location), plus a discharge point characterized as the former NPDES outfall 009 (wastewater outfall). Please clarify for us why the former wastewater outfall was submitted as part of the stormwater sampling effort. We note that the site map drawing identifies Future Outfall SWO09, but that no sampling data is presented for that outfall. We interpret the narrative description of the outfall to indicate that there is no discharge from SWO09 presently. Please confirm our understanding of the narrative description, or provide sampling data for that outfall. Our understanding was that Duke would follow the same format as the Riverbend application in subsequent application submittals, including sample results from all stormwater discharge outfalls. Please provide the missing sampling results for outfall SWO09, or provide a schedule for sampling it, or provide a clarification of the circumstances that indicate that sampling it is not appropriate at this time. Please provide details (dates, locations on site, drainage areas impacted, etc.) about the presence or any past storage and/or releases of polychlorinated biphenyl compounds (PCBs) on site. If there were any known releases, please discuss actions taken to remediate any areas affected. Include information about which drainage areas might have been impacted by PCBs. The graphic presentation of the site subdrainage areas is visually confusing as submitted. Understanding the extent of the subdrainage areas feeding each stormwater discharge point is a key element in our review of the permit application. Please revise the site map drawing to more clearly delineate the subdrainage areas feeding each stormwater discharge point. The graphic presentation needs to be readily understandable so that our review can proceed. Drawing C-002 should require only minimal graphic changes to help us easily understand the site subdrainage areas. In accordance with item V of the EPA Form 2F application, please confirm that Duke has observed all stormwater outfall conveyances on the site, and that Duke is reporting that only outfall SW005 contains non - Division of Energy, Mineral, and Land Resources Energy Section • Geological Survey Section • Land Quality Section 1612 Mail Service Center, Raleigh, North Carolina 27699-1612.919-707-9200 / FAX: 919-715-8801 512 North Salisbury Street, Raleigh, North Carolina 27604 • Internet: http://portal.ncdenr.org/web/Ir/ An Equal Opportunity 1 Affirmative Action Employer— 50% Recycled 110% Post Consumer Paper Mr. Harry Sideris Dan River - Add. Info. August 25, 2014 Page 2 of 2 stormwater flows, and that Duke has reason to conclude that the observed additional flow is groundwater only. For future reference on other stormwater applications for this facility or for other Duke facilities, if any other outfalls were not observed, or they included non-stormwater flows, please detail those conditions in the EPA Form 2F. Also, if any other discharges have occurred during dry periods please indicate how those discharges are currently permitted, or will be permitted. We understand that the site is undergoing demolition of the coal-fired plant. Please provide a schedule and narrative description of the demolition activities that could impact stormwater discharges. Our concern is that the conditions of the stormwater permit should anticipate changing site conditions during the demolition period. We want to check whether conditional provisions addressing the demolition should be written into the permit, and whether the provisions might be structured so as to lapse when the demolition is accomplished. Perhaps related to the demolition and anticipated future conditions, some outfalls are labeled on the site plan as "Former" and some as "Future". Please clarify for us the conditions that pertain at each outfall so characterized. (Some limited explanation is already contained in the application for Future SW009 and Future SW010.) Again, our concern is to assess how to construct the permit conditions to account for discharges that may change over the term of the permit, or that might in the recent past have constituted a permitted outfall. Similarly, we anticipate that the closure of the site's ash ponds may soon be underway, and that the activity may be begun and completed within the term of the stormwater permit. We would expect that some aspects of the ash pond closure activity may present the potential for stormwater pollution (for example, activities such as transport of ash along on-site haul roads.) In so far as is possible at this point in time, please provide information on the ash pond closure that could inform our drafting of the stormwater permit. Aspects such as the location of haul roads, time schedules, and site modifications necessary to accomplish the undertaking would help us assess how the permit should address the stormwater risks from the activity. We are asking that Duke provide this information by September 22, 2014. Otherwise we will return the application as incomplete. Also, please provide an electronic copy of all application materials, including this additional information, along with the submittal. If you have any questions about this matter, please contact me at (919) 807-6378 or bradley.bennett@ncdenr.gov. or Ken Pickle at (919) 807-6376 or ken.pickle(@ncdenr.gov. Sincerely Original signed by Bradley Bennett Bradley Bennett, Supervisor Stormwater Permitting Program cc: John Velte, Duke Energy Progress, Inc. Allen Stowe, Duke Energy Progress, Inc. Winston-Salem Regional Office. DEMLR DEMLR Stormwater Permitting Program Files DWR Central Files