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HomeMy WebLinkAboutNC0000396_Ash basin piping - Inspection project_20150319DUKE ENERGY, PROGRESS March 19, 2015 Mr. Jeff Poupart North Carolina Division of Water Resources 1617 Mail Service Center Raleigh, NC 27699 -1617 Subject: Duke Energy Progress, Inc. Asheville Steam Electric Plant Ash basin piping — Inspection project NC0000396 Buncombe County Dear Mr. Poupart: Environmental Services Duke Energy 526 South Church Street Charlotte, NC 28202 Mailing Address EC13K / P.O. Box 1006 Charlotte, NC 28201 -1006 RECEIVEDlDENROWR MAR 2 0 2015 Water Quality Permitting Sectior As we discussed with you during a recent meeting, Duke Energy (Duke) needs to conduct a video inspection of a section of HDPE pipe leading from the small open water area of the 1964 ash basin (hereinafter referred to as the "Duck pond ") to the outlet piping leading to NPDES permitted outfall 001 at the subject facility. This section of pipe is approximately 50 feet in length and this video inspection is intended to be used as a tool to detect any structural concerns with the section of pipe. To facilitate this work, the water level in the "Duck pond" must be lowered by two feet so this section of pipe can be inspected. Recall that the water in the "Duck Pond" is released to outfall 001 as part of routine operations. Duke intends to use a floating intake on the pump and slowly lower the water in the "Duck pond" over a five day period of time to lessen the potential for re- entrainment of any settled solids. This change in water level equates to a short term increase of approximately 0.16 MGD. All flow will go through the final outfall point and be included in routine sampling. Daily wastewater flow from generation operations will be treated as normal in the rim ditch and routed from the rim ditch directly to the outlet pipe leading to outfall 001 during this temporary period of lowering the "Duck pond ". Upon lowering of the water level in the "Duck pond" a video camera will be inserted into the pipe to perform the inspection. We anticipate that the video inspection itself should be started and completed in one day. After the video inspection, the "Duck pond" will be allowed to return to its original level and the flow to outfall 001 will decrease for some time until the water returns to its original level. Chemical characterization of the water in the "Duck pond" was submitted to your office dated February 4, 2015. If there are additional questions about the characteristics of this water, we would refer you to the facility's submitted Discharge monitoring reports for outfall 001. For Mr. Jeff Poupart March 19, 2015 Asheville pipe inspection Page 2 of 3 additional information, an aerial map is enclosed that identifies the location of this proposed activity. As there is no change to the final release point of this water and no changes to the characteristics of this water, Duke Energy believes that this proposed short term activity will not require NPDES permit modification or other water permitting actions. If you concur, we would appreciate your written (email) acknowledgement of approval to proceed at your earliest opportunity. If you have any questions or concerns regarding our proposed course of action, please contact Mr. Shannon Langley at (919) 546 -2439 or by email at shannon.langley @duke- energy.com. Sincerely, q4 1/0/ Richard E. Baker, Jr., P.E., PMP Director, Environmental Programs, EHS CCP Enclosure RB /esl cc: Laurie Moorhead w /enclosure Shannon Langley w /enclosure— NCRH 14 Mr. Jeff Poupart March 19, 2015 Asheville pipe inspection Page 3 of 3 Attachment to Letter to Jeff Poupart Ash Basin HDPE piping — Inspection project Asheville Plant area of HDPE pipe to be inspected shown in RED