NCS000548_Modification Request (stamped)_20200804

Steam
all
DUKE 320IEastt NC Hwy 1`50
ENERGY: Terrell, NC 28682
828.478.7700
July 8, 2020
North Carolina Dept. of Environmental Quality Attention: Annette Lucas RECEIVED
Division of Water Resources
1617 Mail Service Center AUG 0 4 2020
Raleigh, NC 27699-1617
QENR-LAND QUALITY
ST4RMWATER PERMITTING
Subject: Duke Energy Carolinas, LLC.
New Industrial Stormwater Outfall
Marshall Steam Station (NCS000548) - Catawba County
Dear Ms. Lucas:
Duke Energy plans to add a new industrial stormwater outfall (SW026) at Marshall
Steam Station in order to redirect approximately 200 acres of drainage area from
entering the ash basin. This new outfall is necessary to re-route stormwater away from
the ash basin and to assist in the closure of the ash basin. SW026 will discharge to a
cove of Lake Norman northeast of the ash basin. The stormwater will be re-routed by
clean closing portions of the ash basin and backfilling with soil to establish grades to
construct a stormwater diversion channel and lined stormwater pond. The diversion
channel will be partially grass lined and partially riprap lined. The stormwater pond will
be lined with a 40-mil linear low-density polyethylene geomembrane. The discharge
pipe will be a 48-inch diameter reinforced concrete pipe with a reinforced concrete
energy dissipator structure at the proposed outfall. Attached is a figure that shows the
drainage area for this outfall. It is requested that this outfall be included in stormwater
permit NCS000548 as it is currently being renewed.
If you have questions or need additional information, please contact Robert Wylie at
[phone].
Sincerely,
r
Rick er
General Manager III SCANNED
Marshall Steam Station
Aug a 6 Zaxa
cc: Bethany Georgoulias - Via Email
Zahid Khan - Via Email
Attachment: Figure of SW026 Drainage Area

2 3 4 5 6 7 8 1 REV. q
Y
T SEE 40TE1 LEGEND
PROPOSED MAJOR TOPOGRAPHIC CONTOUR
ma PROPOSED MINOR TOPOGRAPHIC CONTOUR
MAR-152 DRAINAGE AREA
y+mot 199.1 ACRES PROPERTY BOUNDARY
-INDUSTRIAL��+r,
LANDFILL
ILEPHASEI DEMOLITIONLANDFI ASH BASIN WASTE BOUNDARY(APPROXIMATE)
Y,
----------- EXISTING SITE FEATURE BOUNDARY(APPROXIMATE)
i 0ED DRAINAGE AREA BOUNDARY -A-
PRO POSED -
'1. PHASE II
..... ''. PROPOSED MAR-152 STORMWATER DISCHARGE PIPE
ILF 1 PROPOSED MAR-152 STORMWATER BASIN
PROPOSED ' , AND DIVERSION CHANNEL
PHASE III ':r �/� FUTURE SOIL
BORROWAREA
• ILF
PROPOSED PHASE IV NOTES
• �'�•'• • •
PROPOSED MAR-152
t , r STORMWATER DISCHARGE PIPE
1. DURING LANDFILL OPERATIONS,CONTACT WATER IN THE EXPOSED
ILF
• PROPOSED ► CCR WORKING FACE IS CONTAINED AND CONVEYED TO THE
PHASE V "•�,:, ! LEACHATE COLLECTION SYSTEM AND LINED RETENTION BASIN
(NPDES NC0004987)WHILE STORMWATER ON SOIL COVERED AND
�►` `' f FUTURE SOIL VEGETATED SIDE SLOPES WILL BE CONVEYED TO THE PROPOSED
1804 LANDFILL PROPOSED INDUSTRIAL BORROW AREA
I � .,i STORMWATER OUTFACE.
8 FUTURE SOIL (PHASE II) - STORMWATER OUTFALL B—
STRUCTURAL FILL',. -� BORROW AREA ASBESTOS LANDFILL 35'36'53.48"
.. - 41.57 15
� a
+ l' +wwni t- .'~, orr... 1•'F' PHASE 1 SOIL
BORROW AREA'.
q'S1' FUTURE SOIL
;.+80RROVJ AREA
�' ACTIVE ASH BASIN - •�
FUTURE SOIL '
BORROW AREA .. _(, _' .�yr•-III
f�
A=COM
% N MAR-152 DRAINAGE MAP
-- '• -' MARSHALL STEAM STATION
•• + CLOSURE BY EXCAVATION CLOSURE PLAN
CATAWBA COUNTY,NORTH CAROLINA
Z FOR ISSUED FOR APPROVAL
• • \ I r SOALE:AS SHOWN DES: JW
DUKE
DING TYPE: DFTR: MW
ENERGY JOB NO:60572849 CMKO: RJB
•� •1~ DATE:O6/17I2020 ENGR: RJB
"'-�; --,'M c t ♦' FILENAME: MAR-152 Drainage Map.dwg APPD: JB
0 500 1000 15W DWG SIZE DRAWING NO. REVISION
k �.. ANSID FIGURE 1 q
GRAPHIC SCALE (IN FEET) 22.0"xo+.0"
2 3 4 5 6 7 8