NC0004979_Supplemental cooling water pumping_20081113

7
FW: Allen Stean! Station - status of supplemental cooling water
t
Subject: Re: FW: Allen Steam Station - status of supplemental cooling water pumping system project -
Drought mitigation option
From: Tom Belnick <[e-mail]>
Date: Thu, 13 Nov 2008 16:18:52 -0500
To: "Lewis, Ron" <[e-mail]>
Ron- In response to your request, the Division authorizes Duke Energy to operate a permanent cooling
water pumping system, which replaces a temporary structure which was previously authorized by letter
dated May 22, 2008. This permanent structure will operate in accordance with the Duke supplement
titled "Installation and Operational Plans for the Permanent Supplemental Cooling Water System at
Allen Steam Station." These operating requirements include intake screens having slot size openings of
0.125 inches and pumps designed to withdraw at a through screen velocity. at, or below 0.5 fps. This
permanent system will have the capacity to pump at a maximum flow rate of 345.6 MGD to supplement
the existing cooling water system, and will operate on an as -needed basis from July through September.
The facility will continue to perform routine lake monitoring during the period of pumping to assess
limnological conditions in the Catawba River.
NPDES Permit File NC0004979
Duke Energy/Allen Steam Station
Gaston County
Lewis, Ron wrote:
Jackie and Tom,
Have you had a chance to review the permanent system description or have any questions
concerning authorization?
Thanks,
Ron
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
From: Lewis, Ron
Sent: Monday, October 13, 2008 9:25 AM
To: tom.belnick cpncmail.net
Cc: Jackie Nowell
Subject: FW: Allen Steam Station - status of supplemental cooling water pumping system project -
Drought mitigation option
1 of 3 11/13/2008 4:19 PM

Re: FW: Allen Steam Station - status of supplemental coolin� water ...
Tom,
Jackie may have already forwarded the fequest below. I received a response that Susan is no longer
with the NCDENR and you are now thel supervisor for Western NPDES program.
Congratulations on your new role. If
Thanks,
•i
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
From: Lewis, Ron
Sent: Monday, October 13, 2008 9:14
To: Jackie Nowell
Cc: Susan Wilson
Subject: Allen Steam Station - status of
Drought mitigation option
Jackie,
Per final FERC approval of the conveyai
pumping system at Allen Steam Station,
September of 2008. As noted in the attar
water system, the floating intake piping
with the permanent supplemental coolinj
of Allen Steam Station operation for con
months partly due to operation of the tem
generation availability. Based on operatii
specification to operate the permanent sys
rather than continuously is requested. Thi
September 2008, when milder weather pri
discontinue use of the temporary system I
is needed for inclusion in the conveyance
pumping system at Allen Steam Station tt
If any questions, please call.
or Jackie have any questions, please call
cooling water pumping system project -
;e application of the temporary supplemental cooling water
1e temporary system was operated during August and
ied authorization to operate the supplemental cooling
id pumps of the temporary system will now be replaced
water system (see attached description). No curtailment
)liance with thermal limits was necessary during these two
)orary system, as well as mild weather and electric
in of the temporary system, authorization to change the
tem on as needed basis from July through September
s request is based on operation of the temporary system in
vailed and approval was granted by NCDENR to
efore the end of September. Your approval of this request
pplication for the permanent supplemental cooling water
at will be submitted to FERC for approval.
r
2 of 3 1 11/13/2008 4:19 PM

Re: FW: Allen Steam Station - status of supplemental cooling water ...
a.
Thanks,
Ron
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
Tom Belnick
Supervisor, Western NPDES Program
N.C. Division of Water Quality
919-807-6390
919-807-6495 (fax)
[e-mail]
3 of 3 11/13/2008 4:19 PM

"I �:�

FW: Allen Steam Station - status of supplemental cooling water pump...
Subject: FW: Allen Steam Station - status of supplemental cooling water pumping system project -
Drought mitigation option
From: "Lewis, Ron" <[e-mail]>
Date: Mon, 13 Oct 2008 09:25:24 -0400 fJ
To: "[e-mail]" <[e-mail]>
CC: Jackie Nowell <[e-mail]>
Tom,
Jackie may have already forwarded the request below. I received a response that Susan is no longer with
the NCDENR and you are now the supervisor for Western NPDES program.
Congratulations on your new role. If you or Jackie have any questions, please call
Thanks,
Ron
Duke Energy
Mail Code: EC 13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
From: Lewis, Ron
Sent: Monday, October 13, 2008 9:14 AM
To: Jackie Nowell
Cc: Susan Wilson
Subject: Allen Steam Station - status of supplemental cooling water pumping system project - Drought
mitigation option
Jackie,
Per final FERC approval of the conveyance application of the temporary supplemental cooling water
pumping system at Allen Steam Station, the temporary system was operated during August and
September of 2008. As noted in the attached authorization to operate the supplemental cooling water
system, the floating intake piping and pumps of the temporary system will now be replaced with the
permanent supplemental cooling water system (see attached description). No curtailment of Allen Steam
Station operation for compliance with thermal limits was necessary during these two months partly due
to operation of the temporary system, as well as mild weather and electric generation availability. Based
on operation of the temporary system, authorization to change the specification to operate the permanent
system on as needed basis from July through September rather than continuously is requested. This
request is based on operation of the temporary system in September 2008, when milder weather
1 of 2 10/14/2008 1:56 PM

FW: Allen Steam Station - status of supplemental cooling wat6r pump...
prevailed and approval was granted by NCDENR to discontinue use of the temporary system before the
end of September. Your approval of this riquest is needed for inclusion in the conveyance application
for the permanent supplemental cooling w ter pumping system at Allen Steam Station that will be
submitted to FERC for approval.
If any questions, please call.
Thanks,
Ron
Duke Energy
Mail Code: EC13K
526 S. Church Street
Charlotte, NC 28202
Office 980-373-5710
Mobile [phone]
hQ
Content -Description:
Authorization D 05222008.p df
NCDENR DWQ Authorization 0522200 .pdf Content -Type: application/pdf
Content -Encoding: base64
. .. . ......
system
2 of 2
t -Description: Permanent system description.pdf
t -Type: application/pdf
t -Encoding: base64
10/14/2008 1:56 PM

Ronald E. Lewis'
Duke Energy Company
Water Management.
EC13K P.O. Box 1006
Charlotte, North Carolina
Michael,F..Easley, Governor
State of`North Carolina
William G. Ross; Jr., Secretary
Department of Environment and Natural Resources
- Coleen H. Sullins,Director
Divlslon'ofWater Quality
*Y,22,2008
28201 -1006 -
Subject Authorization to.t,;, e.
Temporary Cooling Water.Intake Structure.
NPDES Permit NC0004079'
Duke Power/ Allen Steam Station
Gaston County
Dear,Mr. Lewis:
This letter authorizes the operation of a temporary, supplemental cooling water pumping system atthe existing
Allen Steam`Station electric plant. The system will consist -of nine floating ,:intake :pipes with screened.open ngs
(3/8 'inch square mesh) and pumps designed to(withdraw at a`through screen velocity at or below•'0.5 feet per
second (fps). The intake pipes will pump water from.the.Catawba River 'to ,the station's condenser cooling water
(CCW)` discharge canal, which flows to the South Fork Catawba River. The temporary supplemental cooling
water pumping system will initially pump at the rate of 60, 000 gallons per minute y(gpm) and will be an 11%
increase of the current pumping capacity. .(This temporary intake system will be replaced by :a permanent
pumping system of submerged wedge wire screened piping and pumps designed to Mthdraw-a total of240 000
gpm into four manifolds and four pipes that will discharge into the CCW canal in July 2009.)
This temporary pumping plan has been proposed to -ensure unintenvpted power' production' at this, base load
facility, while mitigating effects on the aquatic community and downstream users. The current proposal has been
reviewed by staff of the NC Division of Water Quality (DWQ).-
The.temporarypumping-plan is authorized to be implemented with the following operational,and design measures
to mmimiZe water quality and biological impacts:
The°temporary supplemental cooling water pumpingsystem will operate. continuously from July 2008
through September 2008 in- conjunction with the operation -of the Allen Steam Station's electrical
generating units.
The Catawba River intake pumps will be positioned , above the river bottom and have an' approach
Velocity less than or equal to 0.5 feet per. ;second across screening wiih '3/8 inch mesh openings to.
minimize fish entrainment and impingement.
➢ The temporary supplemental cooling water pumping 'system "will initially pump at the rate of 60, : 000
gallons per minute (gpm) and will be an 11% increase of the'currenf pumping capacity..
➢ The withdrawal Iocation will be downstream of the existing intake structure and pump the water from the
Catawba River to the condenser cooling water' discharge canal, which #lows, to the South Fork Catawba
River.
➢ The facility will perform routine monthly lake monitoring during the„period of pumping to assess .
hmnological conditions in the Catawba River During July, August and 'September, thermal and DO
profiles will be in the vertical water column at designated downstream sampling; locations, r
161.7 MAIL SERVICE CENTER, RALEIGH NORTH CAROLINA 27699-1617 - TELEPHONE [phone]/FAX 919-733=0719
VISIT us'ON THE WEB AT hitp://62o.e6r.state.nc.u5/NPDES -

NC0004979
Page 2 of 2
May 22, 2008
Please note that this authorization does not IM4ct the legal requirements to obtain other permits which may be
required by the Division of Water Quality, the Division of Land Resources, the Coastal Area Management Act, or
any other federal or local governmental permi .
If you have any questions or need,additional i1brmation, please do not hesitate to contact Jacquelyn M. Nowell of
my stair at [phone], extension 512.
cc: Central Files
NPDES File/NC0004979
Mooresville Regional Office — Surface
Bryn Tracy/Environmental Sciences S,
Protection
SIfICCIPya:
Sof b ts+Dr, W-cestern NPDES Program

INSTALLATION AND OPERATIONAL PLANS FOR THE
PERMANENT SUPPLEMENTAL COOLING WATER SYSTEM
AT ALLEN STEAM STATION
As a part of drought mitigation options approved by the NCDENR Division of Water
Quality, Duke Energy Carolinas, LLC, owner of the Allen Steam Station electric power
generating facility, plans to replace the temporary supplemental cooling water system
with the permanent system. Construction of the permanent system will be in the same
area as the temporary system that lies within the existing industrial power generation
complex (see reference map below). Water will be withdrawn and discharged within the
FERC boundary of Lake Wylie.
MAP OF BELMOM NC—SC HORtH CARpL�NA
M;
MAP OF CHAROLEt7E *m �C 18937-
74 Ok*RANGLE i&xnON-
t! .
Last Edit Mar. 14, 2008 DUKE ENERGY
ALLEN, STATION
TOPOGRAPHIC MAP ONc C' Y
_� �BELMONT �NG`
SCALE 0001,1%. WATER TEMPERATURE; OOPIiROL; SYS(E]A
TEMPORARY ,PIPE'
EROSION AND SEDIMENT =NfROL PLAN
0 2000. 4000 6000` FEEL FILENAME 9933-SK1

The permanent pumping system will consist of four 5-ft diameter water transfer lines
with two intake screens at the end hof each line having slot size openings of 0.125 inches
and pum s esigned o wrtdraw N F-Zt r ug_ sc�een vThe
temporary water transfer line used in 2008 will be buried and become one of four water
transfer lines that will be used t, manage the station's discharge water temperature
between July and September of ea6 year. The pumping capacity through each transfer
line will be 60,000 gpm (86.4 MG). The permanent system will have the capacity to
pump at a maximum flow rate of 2140,000 gpm (345.6 MGD) to supplement the existing
cooling water system and enable Allen Steam Station to extend power production, as well
as continued compliance with thermal limits to assure protection of the aquatic
community and downstream users.
1
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As part of the overall intake screen system, an air backwash system will enable debris
removal from the screen surface by delivering a suitable volume of compressed air to the
inside of the screen body. The exiting air will scour the screen surface to maintain
adequate design flow and through slot velocity characteristics.
bR.-EDGE `IN
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Only minimal disturbance of the shoreline buffer will be required for installation of the
water transfer lines, as directional boring will be used to tunnel under the shoreline.
Dredging of the lake bottom adjacent to the shoreline will be required for installation of
the intake screens a minimum of 20 ft below the full pool level of Lake Wylie, as well as
a temporary sheet pile coffer dam to prevent water from entering the transfer lines during
installation under the shoreline. A hydraulic cutterhead suction dredge will, be used to
transfer approximately 30,000 cy of material to an existing permitted 180 acre
wastewater treatment pond (NPDES Permit No. NC0004979). Dredging will be
conducted per approval of the Army Corps of Engineers.
A portion of the previously cleared area for installation of the temporary system will be
excavated for installation of the pump station and routing of the water transfer lines
underground. From the pumping station, water transfer lines will be routed west from the
pump station, jacked under the railroad tracks, and then proceed northwest around the
south side of the coal pile. The pipes will then turn north-northwest and be jacked under
Plant Allen Road and continue north-northeast to the south end of the cooling water
discharge canal. Approximately 1,300 feet of the proposed construction will be through

the coal storage area south of i
cleared wooded area west of the
grassy area west of the parking
activities will be per approval of
For protection of public recre
installed for the temporary sysi
permanent system as prescribed
Warning signage at the condem
is already installed. Boating tr
impacted, as intake lines will be
No changes in hydro project ope
utilization of the proposed supple
July, August, and September. A
system from Lake Wylie will be
operation of the permanent syster
or 1 % of the maximum withdrx
occur from operation of the temf
response plans. Since the intake 1
elevation of the existing intake
capacity of the system will not be
elevation required for full hydroel
coal pile, 700 feet will be through the previously
al pile and approximately 700 feet will be through a
and switchyard. All land clearing and excavating
NCDENR Division of Land Resources.
:)n within Lake Wylie, warning buoys and signage
i will remain in the area near the intake area of the
the North Carolina Wildlife Resources Commission.
cooling water discharge canal of Allen Steam Station
is along the main channel of Lake Wylie will not be
least 20 ft. below the full pool level.
•ation will be required as a result of construction and
nental cooling water system within Lake Wylie during
1 water withdrawn by the supplemental cooling water
eturned to the lake. Consumptive use associated with
i for three months' is estimated to be less than 1 MGD
val flow. No impact to water conservation plans will
Crary cooling water system, as well as water shortage
nes of the permanent system will be placed at the same
of Allen Steam Station, the maximum withdrawal
limited due to lake level elevation or the critical intake
operation of Lake Wylie Hydro Station.