NC0024406_Tempoary Construction Dewatering_20171215

DUKE
ENERGY®
December 15, 2017
Mr Jeff Poupart, Section Chief
NC DWR Permitting Section
1617 Mail Service Center
Raleigh, NC 27699-1617
Subject: Temporary Construction Dewatering
Belews Steam Station
NCO024406
Stokes County
Dear Mr. Poupart:
RECEIVE®/®EWRI®WR
1EC 212017
peter Resources
'permitting Section
This letter is intended to follow up on recent conversations we have had regarding construction projects at
the subject facility. In accordance with requirements found in state and federal laws, Duke Energy is re-
routing certain wastewaters from ash basins, To continue to treat these wastewaters, new lined wastewater
treatment basins will be constructed. This change was communicated to your office as part of an update to
the pending NPDES permit application for the Belews Steam Station dated August 29, 2016
For the lined wastewater treatment basins to be constructed, groundwater dewatering activities will be
necessary so that construction activities can occur "in the dry." As we discussed, extracted groundwater
in support of construction activities is deemed to be permitted in accordance with 15a NCAC 2H
.0106(f)(7) " . provided that no water quality standards are contravened, or expected to be
contravened " Duke Energy staff have evaluated this activity and determined that it will not lead to
contravention of standards in the receiving waters. Samples of the groundwater have been obtained and
evaluation has occurred based on chemical characteristics of the groundwater, expected maximum
extraction rates, volume of the ash basin treatment system and the receiving waters flow characteristics.
Duke Energy intends to direct this extracted groundwater flow to the station's ash basin where NPDES
compliance sampling occurs to provide additional assurance that the receiving waters are protected. It is
anticipated that the dewatering activities will be necessary for a period of approximately six months.
Longer term groundwater flows from this area will be sent to the Lined Retention Basin as described in the
NPDES permit application amendment dated December 5, 2017.
In conclusion, this temporary project will not significantly change the characteristics of the ash basin
discharge. The construction dewatering will not cause the flow volumes to exceed previous flow volumes
used for determining permit limits. This dewatering project will not result in the contravention of any
water quality standards. As discussed, the construction dewatering operation will begin in the near future.
It is our understanding that DEQ concurs that this operation is deemed permitted and can begin
If there are any questions about this matter, please contact me at [phone] or Joyce Dishmon at
[phone].
Sincerely,
E. Shannon Langley
Lead Environmental Specialist
cc: Sherri Knight — WSRO, 450 West Hanes Mill Road, Suite 300, Winston-Salem, NC 27105
Joyce Dishmon/Filenet - via email
Richard Baker - via email
Julie Grzyb — NC DWR 1617 Mail Service Center Raleigh, NC 27699-1617