NCS000572_Dan River Application Add Info Letter_20140826

NCDENR
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 -
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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 [phone] or [e-mail]. or Ken Pickle at [phone] 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