NCS000572_Dan River Application Modification_20141218

DUKE
ENERGY -
December 17, 2014
Mr. Bradley Bennett
State of North Carolina
Department of Environment and Natural Resources
Division of Energy, Mineral & Land Resources
Stormwater Permitting Program
1612 Mail Service Center
Raleigh, NC 27699-1612
Subject: NPDES Industrial Stormwater Permit Application
Dan River Station
Dear Mr. Bennett:
Environmental Services
Duke Energy
410 S. Wilmington Street
Raleigh, NC 27601
Mailing Address:
Mail Code NCRH 141 P.O. Box 1551
Raleigh, NC 27602
RECEIVED
DEC 18 2014
DENR-LAND QUALITY
STORMINATER PERMITTING
Duke Energy submits the following information as an update to the industrial stormwater permit
application for your consideration; during the development of an industrial stormwater permit for
the Dan River Station. Specifically, the information below addresses decommissioning work
that has the potential to involve the disturbance of coal or coal combustion residuals during
decommissioning activities at the steam station.
The following outfalls are identified as having this potential:
SW003. SW004. SWO05 and SWO06:
These four outfalls convey stormwater from small drainage areas west of the powerhouse.
Their combined drainage area is approximately 3.8 acres. Coal ash residuals may also be
encountered during grading activities and during demolition activities involving the dismantling
of coal or ash handling equipment around the powerhouse area.
Future SWO09:
We request this outfall be added into the permit to address future decommissioning activities.
This outfall conveys stormwater from a 45 acre area including the decommissioned powerhouse
area, coal yard, and the 48 inch pipe area. Coal ash material may be transported through this
area during future removal of coal ash from the site. Coal ash residuals may also be
encountered during grading activities and during demolition activities involving the dismantling
of coal or ash handling equipment around the powerhouse area and removal of railroad and
ballasts. For some period of time the stormwater discharged through this outfall from the
removal of the railroad and ballast will be directed through an in line treatment package before
discharging through the outfall. In the future, as decommissioning of the site progresses, the
yard sumps that are currently used to divert stormwater from the coal pile area and the
breezeway; under the precipitator to the ash basin, will be diverted to the in line treatment
package. This stormwater has the potential of containing coal residuals and coal ash.

Future SW010:
We request this outfall be added into the permit to address future decommissioning activities.
This outfall conveys stormwater from a 77 acre area including the ash stack area, the 36 inch
inlet pipe area and the ash stack perimeter. Coal ash residuals may be drained from the ash
stack and other areas during storm events to future Outfall 010. Coal ash material may be
transported through this area on haul roads during future removal of coal ash from the site.
Coal ash residuals may also be encountered during grading activities and during demolition
activities involving the removal of ash from the ash stack and ash basins, removal of railroad
and ballasts, including a small area of petroleum remediation. Coal ash residuals may also be
taken offsite by rail.
During a site walk down in October Duke Energy identified a stormwater outfall at the Dan River
Steam Station that was inadvertently omitted from the original stormwater permit application
submitted in July 2014. Duke Energy requests the outfall be added to the permit. This outfall is
identified as SW011 and is located adjacent to and west of SW003. This outfall conveys
stormwater from an approximately 1 acre drainage area that contains sections of a railroad track
that Duke Energy plans to remove. Coal residuals are present in the rail bed beneath these
tracks, and coal and coal ash residuals may be encountered during grading activities and during
demolition activities involving the dismantling of coal or ash handling equipment around the
powerhouse area.
Should you have any questions regarding this submittal or require additional information, please
contact Steve Cahoon at 919-546-7457 or email [e-mail].
Since
Steve Cahoon
Sr. Environmental Specialist
Duke Energy Environmental Services Department