NC0001422_Other_20180927

f
41EDUKE L. V. Sutton Energy Complex
5 801 Sutton Steam Plant Rd
ENERGY® Wilmington, NC 28401
o:910.341.4750
f•910.341.4790
•
September 25, 2018 .
Ms. Morella Sanchez-King
State of North Carolina RECEIVED/DENR/DWR
Department of Environmental Quality (DEQ) •
Water Quality Regional Operations . SEP 2 7 2018
127 Cardinal Drive Extension Water Resources,
Wilmington, NC 28405 Permitting Section
Subject: Sutton Energy Complex
NPDES Permit No. N00001422
Written follow up to verbal notification ,
Cooling pond flow into the 1971 ash basin , .fY' ,e r - . '
Dear Ms. Sanchez-King:
On September 20, 2018 at approximately 9:11 pm, staff from Duke Energy made a
verbal notification to Jeff Poupart, DWR permitting Section Chief, that flooding of the
subject facilities cooling pond had caused water to enter the 1971 ash basin at the site.
As has been previously communicated, the site received over 30 inches of rainfall
associated with Hurricane Florence. In days following the Hurricane, flood waters from
the Cape Fear river rose to unprecedented levels and overtopped the Sutton cooling
lake berms on the north end of the structure. This in turn caused the cooling•pond to
rise to levels that led to the overtopping of the steel divider wall between the cooling
pond and the 1971 ash basin. The 1971 ash basin was observed to be filled with water
prior to this overtopping event. At the time of the initial notification, Duke staff reported
that it was unlikely that settled ash from the 1971 basin would be displaced by this
condition. Duke staff have observed the conditions since that time and have not
observed any ash material being displaced, however some cenospheres were observed
to have left the basin and were transported by a mixture of flood waters and waters from
the 1971 basin. Cenospheres are hollow, buoyant, inert spheres made of silica and
alumina. They are filled with inert gas or air. Because of their structural nature,
cenospheres float on the water surface. Booms were deployed in an effort to retain the
cenospheres to the extent possible given site conditions.
Ongoing daily water sampling in the Cape Fear river has been underway upstream and
downstream of our facility since September 18, 2018. The results of these samples
have been shared with your agency staff on an ongoing basis. We will continue to
share our sampling data with you as long as the samples are obtained.

If you have any questions associated with this submittal please contact Steve Cahoon
at 919 546-7457 or [e-mail]. '
/certify, under penalty of law, that this document and all attachments were prepared under
my direction or supervision in accordance with a system designed to assure that qualified
personnel properly gather and evaluate the information submitted. Based on my inquiry of the ,
person or persons who manage the system, or those persons directly responsible for
gathering the information, the information submitted is, to the best of my knowledge and
belief, true, accurate, and complete. I am aware that there are significant penalties for '
submitting false information, including the possibility of fines and imprisonment for knowing ,
violations. , ,
Sin erely i
IiIlir
Jas n Talbott I 1 - ; : ,
General Manager II, Sutton Energy Complex
Fossil/Hydro,Generation -,Carolinas East
Cc: Kent Tyndall } , , .
Steve Cahoon - via email
Shannon Langley.,via email ' ,
Jeff Poupart—DW . , , ,
.1617 Mail Service Center , ,
Raleigh, NC 27699-1617, -