NCG500131_Regional Office Historical File Pre 2018

DIVISION OF WATER QUALITY
July 10,2012
To: Regional Office Personnel
From: Jeff Poupart 511W�
Point sourc-':ranch Supervisor
Subject: NCG 500000 Interpretation of Temperature Monitoring
For Hydroelectric Facilities
The need has arisen for clarification of Part A(2) of the General Permit 500000 regarding Hydroelectric
Facilities. The permit requires monitoring for Temperature at the Effluent,Upstream and Downstream.
Upstream location for the natural water temperature shall be interpreted as the influent to the penstock or
other appropriate location in the impounded waterbody. Effluent is the outflow from the powerhouse.
The temperature change between these two values is considered the heat added and judged for compliance
with Note 1 of the permit and 15A NCAC 2H.0211 (j).

46 4 •A.
1_
NCDENR
North Carolina Department of Environmpnt and Natural Resources iL
Division of Water Quality
Beverly Eaves Perdue Charles Wakild, P.E. Dee Freeman
Governor Director Secretary
June 27,2012
Mr.Allen Stowe, Water Management
Duke Energy
EC13K/Post Office Box 1006
Charlotte,North Carolina 28201-1006
Subject: Compliance Evaluation Inspection
Mt. Island Hydroelectric Station
NPDES Permit No. NCG500131
Gaston County
Dear Mr. Stowe:
Enclosed is a copy of the Compliance Evaluation Inspection Report for the inspection conducted at the subject
facility on June 15,2012 by Mr. Wes Bell of this Office. Please advise the facility's Operator-in-Responsible
Charge(ORC)of our findings by forwarding a copy of the enclosed report.
The report should be self-explanatory; however, should you have any questions concerning this report,please do not
hesitate to contact Mr. Bell at(704)235-2192, or at [e-mail].
Sincerely,
for Robert Krebs
Surface Water Protection Regional Supervisor
Enclosure:
Inspection Report
cc: Gaston County Health Department
WB
Mooresville Regional Office One
Location:610 East Center Ave.,Suite 301 Mooresville,NC 28115 NorthCarolina
Phone:[phone] Fax:[phone] Customer Service:1-877-623-6748 Naturally
www.ncwaterquality.org
An Equal Opportunity\Affirmative Action Employer—30%Recycled/10%Post Consumer paper

United States Environmental Protection Agency Form Approved.
EPA Washington,D.C.20460 OMB No.2040-0057
Approval expires 8-31-98
Water Compliance InspAntinn Report
Section A: National Data System Coding(i.e.3PCS)
Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type
1 I^'I 2 Li 31
NCG500131 111 121 12/06/15 117 1819I 19t e I 20l I
!- 1 Remarks U U U
21IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII66
Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA —— ------Reserved-------
671 1.0 169 70IJ 71 I N I 72I N I 731 I 174 751 I I I I I I 1 80
—! Section B: Facility Data J
Name and Location of Facility Inspected(For Industrial Users discharging to POTW,also include Entry Time/Date Permit Effective Date
POTW name and NPDES permit Number)
09:15 AM 12/06/15 07/08/01
Mountain Island Hydroelectric Station
439 Mountain Island Rd Exit Time/Date Permit Expiration Date
Mount Holly NC 28120 10:35 AM 12/06/15 12/07/31
Name(s)of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) Other Facility Data
///
Robert Steven Jones//704-263-3242/
Winford R Horton//704-382-0801 /
Name,Address of Responsible Official/Title/Phone and Fax Number
Contacted
Jimmie Allen Stowe,526 S Chruch St Charlotte NC 282011002//704-382-4309/7043829840
No
Section C: Areas Evaluated During Inspection (Check only those areas evaluated)
Permit Flow Measurement •Operations&Maintenance •Records/Reports
II Self-Monitoring Program Ill Facility Site Review •Effluent/Receiving Waters •Laboratory
Section D: Summary of Finding/Comments(Attach additional sheets of narrative and checklists as necessary)
(See attachment summary)
Names)and Signature(s)of Inspector(s) Agency/Office/Phone and Fax Numbers Date
Wesley N Bell >l %i, ir MRO WQ//704-663-1699 Ext.2192/ /'__
Signature of Management Q A Rev ewe Agency/Office/Phone and Fax Numbers Dat
M r a All)o co MRO WQ//704-663-1699 Ext.2204/
EPA Form 3560-3(Rev 9-94)Previous editions are obsolete.
Page# 1

NPDES yr/mo/day Inspection Type (cont.) 1
31
NCG500131 111 12I 12/06/15 117 18 1j
Section D: Summary of Finding/Comments(Attach additional sheets of narrative and checklists as necessary)
The facility staff currently collect one sample (outfall locations/base of the dam) as a representative of all
discharges. Effluent samples for temperature, pH, oil & grease, and a totalized flow measurement were
collected/measured on a quarterly basis. Please be advised that all future sampling events (including flow
measurments) must be performed at each discharge outfall. The subject permit requires effluent
temperature, pH, and flow and instream (upstream/downstream) temperature measurements for the
non-contact cooling water discharges. Note: The instream sampling requirements were consistent with the
Permit's requirements.
The effluent from the sump drainage system (with oil/water separation tank) should be sampled for flow, pH,
and oil & grease as required by the subject permit.
Page# 2

Permit: NCG500131 Owner-Facility: Mountain Island Hydroelectric Station
Inspection Date: 06/15/2012 Inspection Type: Compliance Evaluation
Permit Yes No NA NE
(If the present permit expires in 6 months or less). Has the permittee submitted a new application? 0 0 • 0
Is the facility as described in the permit? • n n 0
#Are there any special conditions for the permit? ■ n n n
Is access to the plant site restricted to the general public? Norm
Is the inspector granted access to all areas for inspection? ■ n n n
Comment: The facility has four discharge outfalls that discharge non-contact cooling
water at the base of the dam from the four electric generation units/systems. No
biocides or corrosion inhibitors are added.
In addition, the facility discharges (near base of dam)from an oil/water separation tank
for the sump drainage system.
Record Keeping Yes No NA NE
Are records kept and maintained as required by the permit? ■ n n n
Is all required information readily available, complete and current? ■ n n n
Are all records maintained for 3 years(lab. reg. required 5 years)? ■ n n n
Are analytical results consistent with data reported on DMRs? 0 0 • n
Is the chain-of-custody complete? • 0 0 0
Dates, times and location of sampling •
Name of individual performing the sampling
Results of analysis and calibration •
Dates of analysis •
Name of person performing analyses •
Transported COCs U
Are DMRs complete: do they include all permit parameters? 0 0 • 0
Has the facility submitted its annual compliance report to users and DWQ? n n ■ n
(If the facility is=or>5 MGD permitted flow)Do they operate 24/7 with a certified operator on each shift? n n ■ n
Is the ORC visitation log available and current? n n U n
Is the ORC certified at grade equal to or higher than the facility classification? n n ■ n
Is the backup operator certified at one grade less or greater than the facility classification? 0 0 ■ 0
Is a copy of the current NPDES permit available on site? ■ n n n
Facility has copy of previous year's Annual Report on file for review? n n ■ n
Page# 3

Permit: NCG500131 Owner-Facility: Mountain Island Hydroelectric Station
Inspection Date: 06/15/2012 Inspection Type: Compliance Evaluation
Record Keeping Yet NO NA NE
Comment: The records reviewed during the inspection were organized and well
maintained. Effluent and instream monitoring data were reviewed for 2011 and 2012.
No effluent limit violations and/or instream temperature exceedances were reported.
Operations & Maintenance Yes No NA NE
Is the plant generally clean with acceptable housekeeping? • n n n
Does the facility analyze process control parameters,for ex: MLSS, MCRT, Settleable Solids, pH, DO, Sludge 0 0 ■ 0
Judge, and other that are applicable?
Comment:
Effluent Pipe Yes No NA NE
Is right of way to the outfall properly maintained? n n ■ n
Are the receiving water free of foam other than trace amounts and other debris? ■ n n n
If effluent (diffuser pipes are required) are they operating properly? n n ■ n
Comment: The facility was not generating power at the time of the inspection;
therefore, no discharges were observed. No oil sheens were observed downstream of
the base of the dam.
Page# 4

l L E
SOC PRIORITY PROJECT: No
To: NPDES Unit
Water Quality Section
Attention: Charles Weaver
Date: April 23, 2012
NPDES STAFF REPORT AND RECOMMENDATIONS
County: Gaston
NPDES Permit No.: NCG500131
PART I - GENERAL INFORMATION
1. Facility and address: Mountain Island Hydro Station
do Duke Energy Carolinas, LLC
526 South Church Street—EC13K
Charlotte,N.C. 28202
2. Date of investigation: March 29, 2012
3. Report prepared by: Michael L. Parker, Environmental Engineer II
4. Person contacted and telephone number: Allen Stowe, [phone],Dam- 827-2311.
5. Directions to site: From the jct. of Hwy. 273 and old Hwy. 16 north of the Town of Mount
Holly, travel south on Hwy. 273 miles and turn left on a gravel access road(no SR
number). The Dam is located at the end of this road.
6. Discharge point(s), list for all discharge points*:
Latitude: 35° 20' 03"
Longitude: 80° 59' 12" USGS Quad No.: F 15 SW
*Due to the fact that the four outfalls at this facility are in relative close proximity to each other,
this is an approximation of the latitude/longitude of all four outfalls.
7. Receiving stream or affected surface waters: Catawba River(Lake Wylie)
a. Classification: WS-IV, CA
b. River basin and Subbasin no.: Catawba 030833
c. Describe receiving stream features and pertinent downstream uses: The receiving
stream is the main channel of the Catawba River. The area is used for primary and
secondary recreation and receives bodily contact from various recreational activities.
Downstream users include private, municipal, and industrial WWTPs. There are no
municipal water intakes located for several miles below this facility.

PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. Volume of wastewater (based on maximum flow at each outfall):
Outfall 001 Outfall 002 Outfall 003 Outfall 004
0.1224 0.10656 0.1368 0.1512
The cooling water is made up of lube oil cooling water and thrust bearing cooling water that is
discharged into the tailrace area at the base of the dam.
2. Possible toxic impacts to surface waters: Biocidal additives are not used at this facility;
therefore, no toxic impacts are expected.
PART III - OTHER PERTINENT INFORMATION
1. Special monitoring or limitations (including toxicity) requests: None at this time.
3. Compliance history: This facility has a good compliance history.
PART IV-EVALUATION AND RECOMMENDATIONS
The applicant requests reissuance of the Certificate of Coverage for the discharge of
non-contact cooling water from a hydro electric dam. The dam has four(4) electrical generators which
discharge thrust bearing cooling water and lube oil cooling water through turbine shafts located at the
base of the dam (outfalls 001-004). Operation of the dam is intermittent depending on the electrical
power needs of Duke Energy's service area.
It is recommended that a Certificate of Coverage under the subject GP be reissued as requested.
Signature of Report Preparer D to
r7‘ r c//2.;k._
Water Quality Regional Supervisor Date
h:\dsr\dsr12\Mt Island Hydro.doc

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FOR AGENCY USE ONLY
Date Received
7..4611ilr, Quality A Division of Water Quality Section Year Month Day
/Water
— —� NICIGI Certificate oflCoil �erage
NCDENR National Pollutant Discharge Elimination System Check u Amount
not
rHYkw r,rrT w NON Pr,a rs NCG500000 Permit Assigned to
NOTICE OF INTENT goo IN
National Pollutant Discharge Elimination System application for coverage under General Permit
NCG500000: Non-contact cooling water, boiler blowdown,cooling tower blowdown,condensate, and
similar point source discharges P.
(Please print or type)
1) Mailing address'of owner/operator: I �� 5 LO ?
Company Name Duke Energy Carolinas,LLC • _ r 'N
p y frLJt-:iL ;:=C;!ONAL
Owner Name Allen Stowe-Water Management
Street Address 526 South Church Street,Interoffice-EC13K
City Charlotte State N.C. ZIP Code 28202
Telephone No. (704) 382-4309 Fax: [phone]
*Address to which all permit correspondence will be mailed
2) Location of facility producing discharge:
Facility Name Mountain Island Hydroelectric Station
Facility Contact Randy Horton
Street Address 439 Mountain Island Road
City Mt.Holly State NC ZIP Code 28120
County Gaston
Telephone No. 704 382-9183 Fax: 704 382-0041
3) Physical location information:
Please provide a narrative description of how to get to the facility(use street names, state road numbers,
and distance and direction from a roadway intersection). Take 1-85 S to Hwy 273 going toward Mt.Holly. Pass
Freightliner truck plant on right. Go 1 3/4 miles,turn right on Mt Island Rd beside water tower. Station is at end of road.
(A copy of a county map or USGS quad sheet with facility clearly located on the map is required to be submitted with this application)
4) This NPDES permit application applies to which of the following :
❑ New or Proposed
❑ Modification
Please describe the modification:
• Renewal
Please specify existing permit number and original issue date:
5) Does this facility have any other NPDES permits?
• No
❑ Yes
If yes, list the permit numbers for all current NPDES permits for this facility:
6) What is the nature of the business applying for this permit? Electric Generation
Page 1 of 4 04/05

NCG500000 N.O.I.
7) Description of Discharge:
a) Is the discharge directly to the receiving water? B Yes ❑ No
If no, submit a site map with the pathway to the potential receiving waters clearly marked. This
includes tracing the pathway of the storm sewer to the discharge point, if the storm sewer is the only
viable means of discharge.
b) Number of discharge points(ditches, pipes, channels, etc. that convey wastewater from the
property): Four
c) What type of wastewater is discharged? Indicate which discharge points, if more than one.
8 Non-contact cooling water Discharge point(s)#: 001,002,003,004
❑ Boiler Blowdown Discharge point(s)#:
❑ Cooling Tower Blowdown Discharge point(s)#:
❑ Condensate Discharge point(s)#:
❑ Other Discharge point(s)#:
(Please describe"Other")
d) Volume of discharge per each discharge point(in GPD):
#1: 122,400 #2: 106,560 #3: 136,800 #4 151,200 M-rfil , n
e) Please describe the type of process (i.e., compressor,A/C unit, chiller, boiler, etc.)the wastewater is
being discharged from, per each separate discharge point(if applicable, use separate sheet):_
Hydroelectric generator
8) Please check the type of chemical added to the wastewater for treatment , per each separate discharge
point(if applicable, use separate sheet):
❑ Biocides Name: Manuf.:
❑ Corrosion inhibitors Name: Manuf.:
❑ Chlorine Name: Manuf.:
❑ Algaecide Name: Manuf.:
❑ Other Name: Manuf.:
B None
9) If any box in item (8)above, other than none, was checked, a completed Biocide 101 Form and
manufacturers'information on the additive is required to be submitted with the application for the
Division's review.
10) Is there any type of treatment being provided to the wastewater before discharge (i.e., retention ponds,
settling ponds, etc.)? 0 Yes B No
If yes, please include design specifics(i.e., design volume, retention time, surface area, etc.)with
submittal package. Existing treatment facilities should be described in detail. Design criteria and
operational data (including calculations)should be provided to ensure that the facility can comply with the
requirements of the General Permit. The treatment shall be sufficient to meet the limits set by the
general permits.
Note: Construction of any wastewater treatment facilities requires submission of three(3) sets
of plans and specifications along with the application. Design of treatment facilities
must comply with the requirements of 15A NCAC 2H .0138. If construction applies to
this discharge, include the three sets of plans and specifications with this application.
Page 2 of 4 04/05

NCG500000 N.O.I.
11) Discharge Frequency:
a) The discharge is: 8 Continuous 0 Intermittent ❑ Seasonalo
i) If the discharge is intermittent, describe when the discharge will occur:
ii) If seasonal check the month(s)the discharge occurs: ❑ Jan. 0 Feb. 0 Mar. ❑ Apr.
❑ May 0 Jun. ❑ Jul. ❑ Aug. ❑ Sept. 0 Oct. ❑ Nov. 0 Dec.
b) How many days per week is there a discharge? Seven
c) Please check the days discharge occurs:
Sat. B Sun. IE Mon. IR Tue. B Wed. B Thu. B Fri.
12) Pollutants:
Please list any known pollutants that are present in the discharge, per each separate discharge point(if
applicable, use separate sheet):
13) Receiving waters:
a) What is the name of the body or bodies of water(creek, stream, river, lake, etc.)that the facility
wastewater discharges end up in? If the site wastewater discharges to a separate storm sewer
system (4S), name the operator of the 4S (e.g. City of Raleigh). Catawba River
b) Stream Classification: wS-Ili
14) Alternatives to Direct Discharge:
Address the feasibility of implementing each of the following non-discharge alternatives
a) Connection to a Municipal or Regional Sewer Collection System Not Available
b) Subsurface disposal(including nitrification field, infiltration gallery, injection wells, etc.) Too much flow
c) Spray irrigation Not justifiable, no significant thermal gradient or pollutant load
The alternatives to discharge analysis should include boring logs and/or other information indicating that
a subsurface system is neither feasible nor practical as well as written confirmation indicating that
connection to a POTW is not an option. It should also include a present value of costs analysis as
outlined in the Division's"Guidance For the Evaluation of Wastewater Disposal Alternatives".
15) Additional Application Requirements:
For new or proposed discharges, the following information must be included in triplicate with this
application or it will be returned as incomplete.
a) 7.5 minute series USGS topographic map(or a photocopied portion thereof)with discharge location
clearly indicated.
b) Site map, if the discharge is not directly to a stream, the pathway to the receiving stream must be
clearly indicated. This includes tracing the pathway of a storm sewer to its discharge point.
c) If this application is being submitted by a consulting engineer(or engineering firm), include
documentation from the applicant showing that the engineer(Or firm)submitting the application has
been designated an authorized Representative of the applicant.
d) Final plans for the treatment system (if applicable). The plans must be signed and sealed by a North
Carolina registered Professional Engineer and stamped-"Final Design-Not released for construction".
Page 3 of 4 04/05

NCG500000 N.O.I.
e) Final specifications for all major treatment components (if applicable). The specifications must be
signed and sealed by a North Carolina registered Professional Engineer and shall include a narrative
description of the treatment system to be constructed.
I certify that I am familiar with the information contained in this application and that to the best of my
knowledge and belief such information is true, complete, and accurate.
Printed Name of Person Signing: Carol S.Goolsby
Title: Vice President, Hydro Fleet
(Signatu of Applica t) (Date Signed)
North Carolina General Statute 143-215.6 b(i)provides that:
Any person who knowingly makes any false statement, representation, or certification in any
application, record, report, plan or other document filed or required to be maintained under Article 21
or regulations of the Environmental Management Commission implementing that Article, or who
falsifies, tampers with or knowingly renders inaccurate any recording or monitoring device or method
required to be operated or maintained under Article 21 or regulations of the Environmental
Management Commission implementing that Article, shall be guilty of a misdemeanor punishable by
a fine not to exceed $25,000, or by imprisonment not to exceed six months, or by both. (18 U.S.C.
Section 1001 provides a punishment by a fine of not more than $25,000 or imprisonment not more
than 5 years, or both,for a similar offense.)
Notice of Intent must be accompanied by a check or money order for$100.00 made payable to:
NCDENR
Mail three(3)copies of the entire package to:
NPDES Permits Unit
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Final Checklist
This application will be returned as incomplete unless all of the following items have been
included:
B Check for$100 made payable to NCDENR
B 3 copies of county map or USGS quad sheet with location of facility clearly marked on map
8 3 copies of this completed application and all supporting documents
❑ 3 sets of plans and specifications signed and sealed by a North Carolina P.E.
B Thorough responses to items 1-7 on this application
B Alternatives analysis including present value of costs for all alternatives
Note
The submission of this document does not guarantee the issuance of an NPDES permit
Page 4 of 4 04/05

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SOC PRIORITY PROJECT: No
To: NPDES and SW General Permits Unit
Water Quality Section
Attention: Charles Weaver
Date: April 11, 2007
NPDES STAFF REPORT AND RECOMMENDATIONS
County: Gaston
NPDES Permit No.: NCG500131
MRO No.: 07-05
PART I - GENERAL INFORMATION
1. Facility and address: Mountain Island Hydro Station
c/o Duke Energy Carolinas, LLC
526 South Church Street
Charlotte,N.C. 28202
2. Date of investigation: March 26, 2007
3. Report prepared by: Michael L. Parker, Environmental Engineer II
4. Person contacted and telephone number: Allen Stowe, [phone], Dam - 827-2311.
5. Directions to site: From the jct. of Hwy. 273 and old Hwy. 16 north of the Town of Mount
Holly, travel south on Hwy. 273 ,•2.1 miles and turn left on a gravel access road (no SR
number). The Dam is located at the end of this road.
6. Discharge point(s), list for all discharge points*:
Latitude: 35° 20' 03"
Longitude: 80° 59' 12"
*Due to the fact that the four outfalls at this facility are in relative close proximity to each
other, this is an approximation of the latitude/longitude of all four outfalls.
Attach a USGS Map Extract and indicate treatment plant site and discharge point on map.
USGS Quad No.: F 15 SW
7. Site size and expansion area consistent with application: There is basically no area available
for the construction of WWT facilities, if necessary.

Page Two
8. Topography (relationship to flood plain included): Hilly, 5-20% slopes.
9. Location of nearest dwelling: Approx. 1000+ feet from the site.
10. Receiving stream or affected surface waters: Catawba River(Lake Wylie)
a. Classification: WS-IV, CA
b. River basin and subbasin no.: Catawba 030833
c. Describe receiving stream features and pertinent downstream uses: The receiving
stream is the main channel of the Catawba River. The area is used for primary and
secondary recreation and receives bodily contact from various recreational activities.
Downstream users include private, municipal, and industrial WWTPs. There are no
municipal water intakes located for several miles below this facility.
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1. a. Volume of wastewater (based on maximum flow at each outfall):
Outfall 001 Outfall 002 Outfall 003 Outfall 004
0.1224 0.10656 0.1368 0.1512
b. What is the current permitted capacity: There is no capacity in the current permit.
c. Actual treatment capacity of current facility(current design capacity): N/A
d. Date(s) and construction activities allowed by previous ATCs issued in the previous
two years: There have been no ATCs issued to this facility in the past two years.
e. Description of existing or substantially constructed WWT facilities: There are no
existing WWT facilities nor are any proposed at this time.
f. Possible toxic impacts to surface waters: Biocidal additives are not used at this
facility, therefore, no toxic impacts are expected.
2. Residual handling and utilization/disposal scheme: No residuals are generated at this facility.
3. Treatment plant classification: This facility does not met the minimum criteria for a class I
rating.
4. SIC code(s): 4911 Wastewater code(s): 14 MTU code(s): 00000
PART III - OTHER PERTINENT INFORMATION
1. Is this facility being constructed with Construction Grant Funds or are any public monies
involved (municipals only)? Public monies were not used in the construction of this facility.

ge Three
2. Special monitoring or limitations (including toxicity) requests: None at this time.
3. Important SOC/JOC or Compliance Schedule dates: This facility is neither under an SOC
nor is one being proposed at this time
4. Alternative analysis evaluation: There are no known alternatives other than to discharge.
PART IV- EVALUATION AND RECOMMENDATIONS
The applicant requests reissuance of the Certificate of Coverage for the discharge of non-
contact cooling water from a hydro electric dam. The dam has four(4) electrical generators which
discharge thrust bearing cooling water through turbine shafts located at the base of the dam (outfalls
001-004). Operation of the dam is intermittent depending on the electrical power needs of Duke
Energy's service area.
It is recommended that a Certificate of Coverage under the subject GP be reissued as
requested.
Signature of Report Preparer Date
0/49
Water Quality Regional Supervisor Date
h:\dsr\dsr07\mtisldam.dsr

7110 A 4/91TirAii
lr
NCDENR
North Carolina Department of Environment and Natural Resources
s
Division of Water Quality
Michael F. Easley, Governor William G. Ross,Jr.,Secretary
Alan W. Klimek, P.E., Director
NOTICE OF RENEWAL INTENT
Application for renewal of existing coverage under General Permit NCG500000
Existing Certificate of Coverage (CoC): NCG500131
(Please print or type)
1) Mailing address* of facility owner/operator:
Company Name Duke Energy Carolinas, LLC
Owner Name Allen Stowe, Scientist—Water Management
Street Address 526 South Church Street, EC13K
City Charlotte StateNC ZIP Code 28202 je 1.01-4QI1WOURCES
Telephone Number(704) 382-4309 Fax: [phone] gip D'1\, '-°_```oNAL OFFICE
Email address iastoweaduke-energv.com 000W -71
*Address to which all permit correspondence should be mailed
2) Location of facility producing discharge: FEB 1 52007
Facility Name Mountain Island Hydroelectric Station
Facility Contact Randy Horton
Street Address 439 Mountain Island Road TER ��� ��`j`�OIt
City Mt. Holly State ZIP Code 28120
County Gaston WA ,.�
Telephone Number(704) 827-2311 Fax: [phone]
Email address wrhorton@,duke-energv.com
3) Description of Discharge:
a) Is the discharge directly to the receiving stream? (0 Yes ❑ No
(If no,submit a site map with the pathway to the potential receiving waters clearly marked.This includes tracing the pathway of the
storm sewer to the discharge point, if the storm sewer is the only viable means of discharge.)
b) Number of discharge outfalls (ditches, pipes, channels, etc. that convey wastewater from the
property): Four
c) What type of wastewater is discharged? Indicate which discharge points, if more than one.
® Non-contact cooling water Outfall(s) #: 001,002,003,004
❑ Boiler Blowdown Outfall (s) #:
Page 1 of 3

NCG500000 renewal application
❑ Cooling Tower Blowdown Outfall(s)#:
❑ Condensate Outfall(s)#:
❑ Other Outfall(s)#:
(Please describe"Other")
d) Volume of discharge per each discharge point(in GPD):
#001: 122,400 #002: 106,560#003: 136,800 #004 151,200
4) Please check the type of chemical [s] added to the wastewater for treatment, per each separate discharge
point(if applicable, use separate sheet):
❑ Chlorine ❑ Biocides 0 Corrosion inhibitors 0 Algaecide 0 Other
®None
5) If any box in item(4)above [other than None] was checked, a completed Biocide 101 Form and
manufacturers'information on the additive must be submitted to the following address for approval:
NC DENR/DWQ/Environmental Sciences Section
Aquatic Toxicology Unit
1621 Mail Service Center
Raleigh,NC 27699-1621
6) Is there any type of treatment being provided to the wastewater before discharge(i.e., retention ponds,
settling ponds, etc.)? 0 Yes ® No
(If yes, please include design specifics(i.e..design volume, retention time,surface area,etc.)with submittal package. Existing
treatment facilities should be described in detail. )
7) Discharge Frequency:
a) The discharge is: ®Continuous ❑Intermittent 0 Seasonal*
i) If the discharge is intermittent, describe when the discharge will occur:
ii) *Check the month(s)the discharge occurs: 0 Jan 0 Feb 0 Mar. 0 Apr 0 May 0 Jun 0 Jul 0
Aug. ❑ Sept. ❑ Oct. ❑ Nov. ❑Dec.
b) How many days per week is there a discharge?Seven
c) Please check the days discharge occurs: ® Sat. ® Sun. (83 Mon. ® Tue. ® Wed. ®Thu. ® Fri.
8) Receiving stream[s]:
a) To what body or bodies of water(creek, stream, river, lake, etc.)does the facility discharge wastewater?
If the site discharges wastewater to a separate storm sewer system(4S), name the operator of the 4S
(e.g. City of Raleigh). Catawba River
b) Stream Classification: WS-III
Additional Application Requirements:
Page 2 of 3

NCG500000 renewal application
Additional Application Requirements:
The following information must be included in triplicate [original + 2 copies] with this application or
it will be returned as incomplete.
➢ Site map. If the discharge is not directly to a stream, the pathway to the receiving stream
must be clearly indicated. This includes tracing the pathway of a storm sewer to its
discharge point.
➢ Authorization for representatives. If this application will be submitted by a consulting
engineer (or engineering firm), include documentation from the Permittee showing that the
consultant submitting the application has been designated an Authorized Representative of
the applicant.
Certification
I certify that I am familiar with the information contained in this application and that to the best of
my knowledge and belief such information is true, complete, and accurate.
Printed Name of Person Signing: Carol S. Goolsby
Title: General Manager, Hydro Fleet
1/29/07
(Signature of Appli nt) (Date Signed)
North Carolina General Statute 143-215.6 b (i) provides that:
Any person who knowingly makes any false statement, representation,or certification in any application,record, report,plan or other document
filed or required to be maintained under Article 21 or regulations of the Environmental Management Commission implementing that Article,or who
falsifies,tampers with or knowingly renders inaccurate any recording or monitoring device or method required to be operated or maintained under
Article 21 or regulations of the Environmental Management Commission implementing that Article,shall be guilty of a misdemeanor punishable by
a fine not to exceed$25,000,or by imprisonment not to exceed six months,or by both.(18 U.S.C.Section 1001 provides a punishment by a fine
of not more than$25,000 or imprisonment not more than 5 years,or both,for a similar offense.)
a rzasasasasasasasasacasa
This Notice of Renewal Intent does NOT require a separate fee.
The permitted facility already pays an annual fee for coverage under NCG500000.
aEaEaEasacacacacacaEaEa
Mail the original and two copies of the entire package to:
Mr. Charles H. Weaver
NC DENR / DWQ / NPDES
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Page 3 of 3

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MAP OF THE AREA AROUND •
MT. ISLAND HYDRO STATION
SCALE 1:24000
1 rAE ,h o 'mu
1000 0 1000 2000 3000 4000 5000 6000 7000 FEET
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001 - Unit 1 Lube Oil Cooler Cooling Water Discharge To
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Guide Bearing Reservoir Tub.
002 - Unit 2 Lube Oil Cooler Cooling Water Discharge To
Tailwater Through Turbine Shaft Water Cooled Wood
Guide Bearing Reservoir Tub.
003- Unit 3 Lube Oil Cooler Cooling Water Discharge To
Tailwater Through Turbine Shaft Water Cooled Wood — DUKE POWER COMPANY
MOUNTAIN ISLAND HYDRO STATION
Guide Bearing Reservoir Tub. ___" .
004 - Unit 4 Lube Oil Cooler Cooling Water Discharge To NATIONAL POLLUTANT DISCHARGE
ELIMINATION SYSTEM (NPOES)
Tailwater Through Turbine Shaft Water Cooled Wood POINT SOURCE DISCHARGES
Guide Bearing Reservoir Tub. —
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Tailwater Through Turbine Shaft Water Cooled Wood
Guide Bearing Reservoir Tub. SCALE' 1"•Iee'
003 - Unit 3 Lube Oil Cooler Cooling Water Discharge To
Tailwater Through Turbine Shaft Water Cooled Wood
Guide Bearing Reservoir Tub. DUKE POWER CDhPANY
MOUNTAIN ISLAND HYDRO STATION
004 - Unit 4 Lube Oil Cooler Cooling Water Discharge To NATIONAL POLLUTANT DISCHARGE
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INAPECTEO DWG. NO. MI-NPOES-1 e

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To: Permits and Engineering Unit SOC PRIORITY PROJECT: No
Water Quality Section
Attention: Susan Robson
"r` Date: September 17 , 1993
NPDES STAFF REPORT AND RECOMMENDATIONS
County : Gaston
NPDES Permit No. : NCG500131
MRO No . : 93-182
PART I - GENERAL INFORMATION
1 . Facility and Address : Mountain Island Hydro Station
c/o Duke Power Company
13339 Hagers Ferry Road
Huntersville, N.C. 28078-7929
2 . Date of Investigation: September 14 , 1993
3 . Report Prepared By: Michael L . Parker, Environ. Engr . II
4 . Person Contacted and Telephone Number: Jennifer Rudisill ,
(704) 875-4610 , Dam - 827-2311 .
5 . Directions to Site: From the jct . of hwy. 273 and old hwy .
16 north of the Town of Mount Holly, travel south on hwy.
273 t2 . 1 miles and turn left on a gravel access road (no SR
number) . The Dam is located at the end of this road .
6 . Discharge Point(s) , List for all discharge Points : -
Latitude: 35° 20 ' 03"
Longitude: 80° 59' 12"
Attach a USGS Map Extract and indicate treatment plant site
and discharge point on map.
USGS Quad No. : F 15 SW
7 . Site size and expansion area consistent with application:
There is basically no area available for the construction of
WWT facilities, if necessary.
8 . Topography (relationship to flood plain included) : Hilly,
5-20% slopes .
9 . Location of Nearest Dwelling: Approx . 1000+ feet from the
site.

Page Two
10 . Receiving Stream or Affected Surface Waters : Catawba River
(Lake Wylie)
a. Classification: WS-IV CA
b. River Basin and Subbasin No . : Catawba 030833
c . Describe receiving stream features and pertinent
downstream uses : The receiving stream is the main
channel of the Catawba River . The area is used for
primary and secondary recreation and receives bodily
contact from various recreational activities .
Downstream users include municipal and industrial
WWTPs . There are no municipal water intakes located
within several miles below (downstream) this facility .
PART II - DESCRIPTION OF DISCHARGE AND TREATMENT WORKS
1 . a . Volume of Wastewater: 0 . 1728 MGD (Total flow for all
discharges)
b. What is the current permitted capacity: N/A
c . Actual treatment capacity of current facility (current
design capacity) : N/A
d. Date(s) and construction activities allowed by previous
ATCs issued in the previous two years : N/A
e. Description of existing or substantially constructed
WWT facilities : There are no existing WWT facilities
nor are any proposed .
f . Description of proposed WWT facilities : N/A
g . Possible toxic impacts to surface waters : None
expected.
h. Pretreatment Program (POTWs only) : N/A
2 . Residual handling and utilization/disposal scheme: No
residuals will be generated at this facility.
3 . Treatment Plant Classification: Less than 5 points; no
rating (include rating sheet) . Facility does not met the
minimum criteria for a class I rating .
4. SIC Code(s) : 4911
Wastewater Code(s) :
Primary: 14
Secondary: N/A
5 . MTU Code(s) : OG000
PART III - OTHER PERTINENT INFORMATION
1 . Is this facility being constructed with Construction Grant
Funds or are any public monies involved (municipals only)?
No

Page Three
2 . Special monitoring or limitations (including toxicity)
requests : None at this time .
3 . Important SOC/JOC or Compliance Schedule dates : N/A
4 . Alternative Analysis Evaluation: N/A
PART IV - EVALUATION AND RECOMMENDATIONS
The applicant requests issuance of an NPDES GP Permit for
the discharge of non-contact cooling water from a hydro electric
dam. The dam has four (4) electricity generators which discharge
thrust bearing cooling water through turbine shafts located at
the base of the dam (outfalls 001-004) . Each turbine can
discharge up to 0 . 04320 MGD for a total discharge flow of 0 . 1728
MGD. Operation of the dam is intermittent depending on the power
needs of Duke Power's electrical system.
It is recommended that a GP be issued as requested.
� 1-ef t /� 93
Si nature o4 eport Preparer Date
/-1- G - Zo -73
Water Qua ty Region Supervisor Date

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Pre of North Carolina
partment of Environment, -i if a lc TA
Health and Natural Rpcnv ir.. yA • •
�, Division ,nn�� y/2/�7 ment /� A
w, James E ��� " �
�,1 Jonathal ''''_
1�� A. Presto h,e,� �. .r
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A. C. DEFT. OF NATURAL
r \ ly 28, 1993 RESOURCES AND
COMMUNITY DEVELOPMENT
t U Timothy L. Huffman, P.E. JUL 3 p 1993
Duke Power Company
a 13339 Hagers Ferry Road
VP
AHuntersville, NC 28078-7929 QF EN9IAONMENiAI MANAGEMENT
Y60RESVILIE RE610ah:1 OFFICE
Subject: NOI Application
nn NPDES: NCG500131
11- ` Mountain Island Hydro.
C6l'( LAt Gaston County
Dear Mr. Huffman:
This letter is to acknowledge receipt of your application dated June 21, 1993 for
coverage under General Permit for non-contact cooling water and similar discharges. The
permit number highlighted above has been assigned to the subject facility. By copy of this
letter, we are requesting that our Regional Office Supervisor prepare a staff report and
recommendations regarding this discharge.
If you have questions regarding this matter, please contact Susan Robson at(919)
733-5083.
Sincerely,
4 4 c4-
Coleen Sullins, P.E.
Supervisor, NPDES Group
cc: )
Permits and Engineering Unit
Central Files
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
An Equal Opportunity Affirmative Action Employer 50% recycled/ 10% post-consumer paper

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State of North Carolina
Department of Environment, Health and Natural Resources
Division of Environmental Management
512 North Salisbury Street• Raleigh,North Carolina 27611
James G. Martin,Governor A.Preston Howard,Jr.,P.E.
William W. Cobey,Jr., Secretary Acting Director
NOTICE OF INTENT
National Pollutant Discharge Elimination System
Application for Coverage under General Permit NCG500000;Non-contact cooling water,boiler blowdown,
cooling tower blowdown,condensate,and similar point source discharges.
1. Name,Address,'^cation,and telephone number of facility requesting Permit.
A. Official Name: Duke Power Co. , Mountain Island Hydroelectric Station
B. Mailing Address: c/o GM) water Protection Group
(1)StreetAddress; 13339 Hagers Ferry Road
(2)City; Huntersvi l l e
(3)State; N C
(4)Zip; 2807 8-7 92 q
(5)County; Met kl anhurcgg
C. Location.(Attach map delineating general
facility location) Mtn. Island Rd.
(1)Street Address; RouteBOX
(2)City; Mount Holly
(3)State; N.C.
(4)County; r.a s t n n
D. Telephone Number; ( 704 ) 827 - 2311
2. Facility Contact:
A. Name; Howard M Lane
B. Title; Supervisor
C. Company Name; Du P Power Company
D. Phone Number, ( 704 ) 8 27 - 2311
3. Application type(check appropriate selection):
A. New or Proposed; x
B. o;
ET.ustExisting; Lf previously JivuSl,permitted,provide iiue permit number
and issue date .
C. Modification;
(Describe the nature of the modification):
4. Description of discharge
A.Please state the number of separate discharge points.
1,[] ; 2,[] ; 3,[] ; 44; _.�].
*
B.Please describe the amount of wastewater being discharged per each separate discharge point 1:
gallons per day(gpd) 2` (gpd) 3; * (gpd) 4; * (gpd)
*Each can discharge 43,200 gpd for a combined total maximum possible discharge of
172,800 Gpd
Page 1

C.Check the duration and frequency of the discharge,per each separate discharge point:
Continuous:_
•
2. Intermittent (please describe): When unit is running
. Seasonal(check month(s)the discharge occurs):January[];February[];March[];April[],
May[];June[];July[];,August[];September[];October[];November[];December[].
4. How many days per week is there a discharge?(check the days the discharge occurs)
Monday[], Tuesday[], Wednesday[], Thursday[],Friday[], Saturday[], Sunday[].
Discharge can occur any day
5. How much of the volume discharged is treated?(state in percent) 0 %
D. What type of wastewater is discharged,per separate discharge point.(place check next to correct type):
1. Non-contact cooling water, x
2. Boiler blowdown;
3. Cooling tower blowdown;
4. Condensate;
5. Other(please describe);
Please list any known pollutants that are present in the discharge, per each separate discharge point(if
applicable):
E. Please describe the type of process the cooling water is being discharged from,per separate discharge point
(i.e.compressor,boiler blowdown,cooling tower blowdown,air conditioning unit,etc.):
Non-contact cooling water
F. Please check the type of chemical added to the wastewater for treatment or other,per separate discharge
point:
1. Biocides;
2. Corrosion inhibitors;
3. Chlorine;
4. Algae control;
5. Other(please describe);
6. None; x
If 1,2,3,4,or 5 was checked,please state the name and manufacturer of the chemical additive. Also include
a completed Biocide 101 form,and manufacturers'information on the additive with the application for the
Division's review.
G. Is there any type of treatment being provided to the wastewater before discharge (i.e. retention ponds,
settling ponds, etc.); if yes, please describe. Give design specifics (i.e. design volume, retention time,
surface area, etc.). Existing treatment facilities should be described in detail and design criteria or
operational data should be provided(including calculations) to ensure that the facility can comply with
requirements of the General Peunit.
NOTE: Construction of any wastewater treatment facilities require submission of three (3) sets of plans and
specifications along with their application. Design of treatment facilities must comply with requirement
15A NCAC 2H .0138. If construction applies to the discharge, include the three sets of plans and
specifications with the application.
5. What is the nature of the business applying for this permit? Public Utility, Electric Power
Generating Station
6. Name of receiving water. Cat a w ha R i v a r Classification: W S I I I
(Attach a USGS topographical map with all discharge point(s)clearly marked)
Page 2

barge directly to the receiving water?(Y,N) Y
o, state specifically the discharge point. Mark clearly the pathway to the potential receiving waters on the
ite map. (This includes tracing the pathway of the storm sewer to its discharge point,if a storm sewer is the
only viable means of discharge.)
8. Please address possible non-discharge alternatives for the following options:
A.Connection to a Regional Sewer Collection System; Not a v a i l able
B.Subsurface Disposal; Too much flow
C.Spray Irrigation; Not justifiable, water carries no pollutants
9. I certify that I am familiar with the information contained in the application and that to the best of my knowledge
and belief such information is true.complete,and accurate.
Printed Name of Person Signing M.D. McIntosh
Title V.P. Fossil & Hydro Production Dept.
' Date Application Signed4(''' /9 9.3
Signature of Applicant < ��„"e-X.U
NORTH CAROLINA GENERAL STATUTE 143-215.6B (i) PROVIDES THAT:
Any person who knowingly makes any false statement,representation, or certification in any application,record,
report,plan or other document filed or required to be maintained under Article 21 or regulations of the Environmental
Management Commission implementing that Article,or who falsifies,tampers with or knowingly renders inaccurate
any recording or monitoring device or method required to be operated or maintained under Article 21 or regulations of
the Environmental Management Commission implementing that Article, shall be guilty of a misdemeanor
punishable by a fine not to exceed$10,000,or by imprisonment not to exceed six months,or by both. (18 U.S.C.
Section 1001 provides a punishment by a fine of not more than$10,000 or imprisonment not more than 5 years,or
both,for a similar offense.)
Notice of Intent must be accompanied by a check or money order for$400.00 made payable to the North Carolina
Department of Environment,Health,and Natural Resources. Mail three(3)copies of entire package to:
Division of Environmental Management .
NPDES Permits Group
Post Office Box 29535
Raleigh, North Carolina 27626-0535
Page 3

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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB.
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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB.
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WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB. MOUNTAIN ISLAND HYDRO STATION
NATIONAL POLLUTANT DISCHARGE
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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT POINT SOURCE DISCHARGES
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB. -
DESIGNER DATE INSP. DATE
DRAWNE• H CADDELL DATE 6/01/93 INSP. DATE
DR D. RELEASED FOR NPDES APPLICATION EHC 6931 CHECKED DATE APPR. DATE
CIVIL ELEC. HECK. REV.
NO. REVISIONS DRN DATE CHKD DATE APPR DATE DWG. NO. MI-NPDES-2
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WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB. _ POINT SOURCE DISCHARGES
DESIGNER DATE INSP. DATE
6-01 DRAWNE. H. CADDELL DATE 6'0l/93 INSP. DATE
ORIG. RELEASED FOR NPDES APPLICATION EHC _93 CHECKED DATE APPR. DATE
ERN: NO. REVISIONS DRN DATE CHKD DATE APPR DATE CIVIL
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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT DUKE POWER COMPANY
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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT ELIMINATION SYSTEM ( NPDES)
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB. POINT SOURCE DISCHARGES
DESIGNER DATE INSP. DATE
DRAWNE. H. CADDELL DATE 6/01/93 INSP. DATE
ORI0. RELEASED FOR NPDES APPLICATION EHC MI CHECKED DATE APPR. DATE
ERN: NO. REVISIONS N DATE CHKD DATE APPR DATE CIVIL ELEC. MECH.
INSPECTED DWG. NO. MI-NPDES-1 REV.
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April 18 1994
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WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB.
002 --- UNIT 2 GENERATOR THRUST BEARING OIL COOLER COOLING
WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB.
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WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT DUKE POWER COMPANY
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB. MOUNTAIN ISLAND HYDRO STATION
NATIONAL POLLUTANT DISCHARGE
004 --- UNIT 4 GENERATOR THRUST BEARING OIL COOLER COOLING ELIMINATION SYSTEM ( NPDES)
WATER DISCHARGE TO TAILWATER THRU TURBINE SHAFT PAINT SOURCE DISCHARGES
WATER COOLED WOOD GUIDE BEARING RESERVOIR TUB.
DESIGNER DATE INSP. DATE
DRAWS. H. CAODELL DATE S/0I/93 INSP. DATE
ORID. RELEASED FOR NPDES APPLICATION EHC 693I CHECKED DATE APPR. DATE
CIVIL ELEC. MECH. REV.
NO. REVISIONS ORN DATE CHKD DATE APPR DATE - DWG. NO. MI-NPDES-2
ERN: INSPECTED 0

April 18 1994