NC0003468_Final Permit_20161024

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• A UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
$ c ATLANTA FEDERAL CENTER
61 FORSYTH STREET
yr4( PR01'-C ATLANTA, GEORGIA 30303-8960
OCT Z 4 2016
Mr. S. Jay Zimmerman
Director, Division of Water Resources
North Carolina Department of Environmental Quality
Division of Water Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Re: Review of Draft Final Permit
Duke Energy Carolinas, LLC, Dan River Combined Cycle Station
National Pollutant Discharge Elimination System Permit NC0003468
Dear Mr. Zimmerman:
On July 26, 2016, a revised draft National Pollutant Discharge Elimination System (NPDES) permit and
supporting documents for the above referenced facility were received by the U.S. Environmental
Protection Agency from the North Carolina Department of Environment Quality (NC DEQ), Division of
Water Resources (DWR). The EPA completed its review of the draft permit and provided its comments
and recommendations with respect to the draft permit in a letter dated September 1, 2016.
The EPA received a draft final permit from NC DWR via email on October 5, 2016. On October 19,
2016, staff from our respective agencies participated in a teleconference to discuss the EPA's review of
the draft final permit. Following the teleconference, a revised draft final permit was transmitted to the
EPA from NC DWR via email. The majority of the EPA's comments were addressed. However, in
accordance with Section IV.13.6 of the NPDES Memorandum of Agreement between the EPA and NC
DEQ, the EPA reiterates these comments and recommendations, which have not been addressed:
Parts I. A. (3.) and I. A. (4.) of the permit state that wastewater from decanting and dewatering
operations shall be treated by physical -chemical treatment facilities. However, the permittee has
not yet determined which treatment technologies will be used. The permit should include a
requirement for submittal of plans for the proposed treatment technologies, as well as
notification of the re -direction of wastewater through the treatinent facilities and commencement
of discharges of that treated wastewater through Outfall 002.
• Parts I. A. (3.) and 1. A. (4.) of the permit should include weekly monitoring for total chromium,
total lead, total cadmium, total copper, total zinc and total dissolved solids. In addition, the
monitoring requirement for total iron should be amended"to a weekly basis, not only if
wastewater from boiler chemical cleaning is generated and discharged to the ash basin.
• The EPA does not currently have enough information to determine where the seeps emerge or
reach jurisdictional waters of the United States. We recommend that the United States Army
Corps of Engineers verify any jurisdictional determination before the permit is finalized. To the
Internet Address (URL) • http://www.epa.gov
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extent that any of the "effluent channels" meet the criteria for "waters of the United States"
under the Clean Water Act, DWR does not possess authority to change the jurisdictional status
by designating a jurisdictional feature to be an "effluent channel." Further, in any case where a
feature determined to be an "effluent channel" by DEQ meets the criteria of "waters of the
United States," the permit must include effluent limits stringent enough to ensure that the
discharge will not cause or contribute to a violation of water quality standards, as required by
Section 301(b)(1)(C) of the CWA and 40 CFR Section 122.44(d).
• Part I. A. (23.) references a "Plan for Identification of New Discharges" as Attachment 2, but the
Attachment was not provided with the draft final permit. The Plan should be included in the final
permit in order to clearly define enforceable minimum requirements for identifying unpermitted
discharges.
Finally, as we have discussed, the proposed final permit authorizes discharges from unengineered seeps
that are not discharged through an engineered outfall or collected and rerouted to an engineered
outfall. This creates challenges in permit -development and compliance monitoring as it is unclear how
such discharges can be accurately monitored for flow and discharge characterization. We note that an
enforcement mechanism providing for elimination or rerouting of these seeps is an alternative and
potentially preferable approach for addressing seeps of this nature. It has been North Carolina's election
to develop permits for these discharges rather than addressing them through an enforcement mechanism,
notwithstanding the difficulty of developing appropriate permit conditions and monitoring compliance.
The EPA has no further comments. If you have any questions, please do not hesitate to contact me at
(404) 562- 9470 or Ms. Denisse Diaz at [phone].
Sincerely,
AamesD.ttina, Director
Water Protection Division
cc: Mr. Harry Sideris, Senior Vice President
Duke Energy Carolinas, LLC