NCS000548_SW003 Tier 3 completed_20241111

Eplin, Jerry W
From: La Sala, Joseph Scott <[e-mail]>
Sent: Monday, November 11, 2024 2:35 PM
To: Eplin, Jerry W
Subject: [External] DE Marshall Steam Station NCS000548 - SWO03 Tier 3 completed
Attachments: MSS.SW003.Tier3.complete.notification(1 1.1 1.24).pdf
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Mr. Eplin,
Please find the attached notification of compliance for completion of Tier 3 requirements for stormwater outfall
SWO03 as outlined in NPDES NCS000548. ATier 3 notification was provided to the agency on March 27,2024, and
a Tier 3 Action Plan was subsequently prepared and submitted on April 15,2024. Following completion of
installing the Action Plan BMPs in May 2024, Mercury has since been reported below the benchmark of 12
nanograms per liter(ng/L)for three consecutive monitoring events and Marshall Steam Station will resume
quarterly monitoring for this outfall.
A hard copy of this notification letter is being submitted to your attention for agency records. Please don't hesitate
to contact me if you have any questions about this notification.
Thanks,
Scott
scatt La sa iy Ply'
Lead EHS Consultant I Marshall Steam Station
Office 828.478.7820 1 Mobile [phone]
8320 East NC HWY 150
Terrell, NC 28682
joseph.lasalaa_duke-energy.com
f DUKE
ENERGY.
Society grows great when old men plant trees whose shade they know they shall never sit in.
Ancient Greek Proverb
1

Duke Energy
DUKE Marshall Steam Station
ENERGY 8320 East NC Highway 150
Terrell, NC 28682
CAROLINAS
November 11, 2024
Mr. Jerry Eplin, Regional Engineer
NC DEQ DEMLR— Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, North Carolina 28115
RE: Duke Energy Carolinas LLC, Marshall Steam Station
Industrial Stormwater NPDES Permit No. NCS000548
Tier 3 Monitoring Obligations
Catawba County, North Carolina
Dear Mr. Eplin,
Please accept this letter as notification of compliance with monthly stormwater sampling and our
return to quarterly sampling for Outfall SW003 in accordance with part D-7 ofNPDES Permit
NCS000548. The previous three (3) consecutive sampling events and results for Mercury are as
follows:
Sample Collection Date Result Benchmark
May 15,2024 8.3 ng/L 12 ng/L
June 2024 NO FLOW ---
July 2024 NO FLOW - -
August 13,2024 8.8 ng/L 12 ng/L
September 16,2024 10 ng/L 12 ng/L
We are pleased to report that Duke Energy has completed the obligations associated with the
Action Plan submitted to your office in May of 2024. Action Plan Best Management Plan
(BMP) action items included:
BMP Action Item Completion Date
* Installation of new sediment filter dikes May 2024
* Installation of new metals filter dikes May 2024
These actions conclude all actions of the Action Plan and this notification satisfied Part D-7 and
Part D Table 10 item vii. OfNPDES Permit NCS000548.
Please contact Scott La Sala, Environmental Field Support Professional at Marshall Steam
Station (828-478-7820, or ioseph.lasala i ,duke-energy .com) if you have any questions regarding
this notification submittal
Sincerely,
,Jeffrey Flan =
General Manager III
Marshall Steam Station
cc:J.Scott l.a Sala,Carolinas West Field Support
Don Safrit,Carolinas Permitting&Compliance
www.duke-energy.com