NC0004774_Request for Concurrence of Essential Maintenance_20160314

jeit DUKEEHS-CCP
� 410 South Wilmington Street
ENERGY,E RGY�
Mail Code NC 15
Raleigh, NC 27601
March 14, 2016
Mr. Jeffrey Poupart, Section Chief
NC Division of Water Resources
1617 Mail Service Center
Raleigh, NC 27699-1617 RECE��IEDINC°E��VV
Subject: Request for concurrence of o\
essential maintenance �1uallty
Buck Steam Station vy \ti Sectio''
Permit Number: NC0004774 Pe�mt��n9
Rowan County
Dear Mr. Poupart,
In accordance with guidance received from you on November 18th, 2015, Duke Energy hereby
requests concurrence that lowering the ash basin at the subject facility to install an alternative
ash basin dam spillway is considered essential maintenance under the terms of the subject
permit. While there is no immediate threat, the alternate spillway is proposed to be installed to
mitigate potential impacts to the existing outlet that could result from a seismic event. The
engineering plans were submitted to NC DEQ Dam Safety staff for approval on February 29,
2016.
In order to install the alternate spillway, the ash basin water level must be lowered by
approximately 2.5 feet. Duke intends to lower the water level through the removal of stoplogs.
Flows from the basin will be continue to be released through the existing outfall location where
they will be sampled and measured in accordance with the terms of the subject NPDES permit.
Notification will be provided to the DEQ DWR regional office at least 48 hours prior to
commencement of lowering the water level.
Duke Energy requests your concurrence with this activity. If you have any questions regarding
this activity, please contact me at [phone] or [e-mail].
Sincerely,
E. Shannon Langley
Lead Environmental Specialist
Cc. Corey Basinger - DEQ Regional Office Supervisor
Dale Wooten - Plant Environmental Coordinator
Buck System Owner -
Ross Hartfield - SME
Shannon Langley — NCRH 15th floor