NC0004979_Report_20201118

From: Glenn, Elizabeth
To: Bell, Wes
Cc: Khan, Zahid; Tuvia, Ori A
Subject: [External] Allen FGD SW Pond 5Day Response Letter
Date: Wednesday, November 18, 2020 7:57:42 AM
Attachments: Allen FGD SW Pond 5Dav Letter SIGNED 111720.odf
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Mr. Bell —
Please accept the 5 day response letter concerning the Allen Station FGD Stormwater Pond overflow
event that occurred on 11/12/2020.
If you have any questions, please contact me at the information below.
Thank you,
J. Elizabeth Glenn
Permitting & Compliance
Duke Energy, Environmental Services
Office: [phone]
Cell: [phone]

DUKE
ENERGY,
CAROLINAS
November 17, 2020
Mr. Wes Bell
North Carolina Dept. of Environmental Quality
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Subject: Allen Steam Station
NPDES Permit #:N00004979
Gaston County
Dear Mr. Bell:
Allen Steam Station
253 Plant Allen Roao
Belmont, NC 28012
Duke Energy submits this written notification and status update, as required by NPDES permit
NC0004979 Part II Section E.9., of the Flue Gas Desulfurization area Stormwater Basin
(hereinafter "Stormwater Basin") overtopping that occurred at Allen Steam Station on November
12, 2020, and as verbally reported to the Agency on November 12, 2020,
The Flue Gas Desulfurization Stormwater Basin became inundated and started to overflow at
9:21 a.m. The overflow occurred until 11:19 a.m. It is estimated that 3,000 gallons of primary
stormwater left the basin and entered a tributary which flows into South Fork Catawba River.
Subsequent sample results of water in the FGD Stormwater Basin indicated a pH was 6.8 SU.
The receiving water body was inspected and no adverse impacts were observed.
Station personnel and environmental staff surveyed the areas, post storm event. Included in this
survey was a review of the nearest perennial stream that empties into the station's cooling water
discharge canal. No indication of environmental impacts from the overtopping were observed.
If you have any questions, please contact Ms. Elizabeth Glenn [phone] or
Elizabeth. lenn @duke-ener_qy.com.

I 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,
cVer
Ri
General Manager III
Allen Steam Station
Fossil/Hydro Operations - Carolinas Coal Generation
CC: Ori Tuvia —NCDEQ Mooresville Regional Office
Zahid Khan - NCDEQ Mooresville Regional Office