NC0004961_Draft Permit_20150306

NCDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory
Governor
Mr Harry Sidens, Senior Vice President
Environmental, Health and Safety
Duke Energy Carolinas, LLC
Mail Code EC13K
P.O Box 1006
Charlotte, North Carolina 28201-1006
Dear Mr. Sideris-
Donald R. van der Vaart
Secretary
March 6, 2015
Subject. Draft NPDES Permit
Permit NC0004961
Riverbend Steam Station
Gaston County
Facility Class I
Enclosed with this letter is a copy of the draft permit for your facility Please review the draft
very carefully to ensure thorough understanding of the conditions and requirements it contains
The draft permit contains the following significant changes from your current permit:
• Monitoring requirements for Outfall 001 were adjusted due to the discontinuation of once -
through cooling water discharges.
• The Ash Pond Closure Special Condition was updated (Please see A (15 )).
• The Seep Outfall 010 (Please see A. (5.)) and Seep Pollutant Analysis Special Condition (Please
see A. (17 )) were added to the permit.
• The Appendix A and Appendix B were added to the permit
• A separate effluent page for the dewatering of the ash ponds (Outfall 002) was added to the
permit (Please see Special Condition A (3 )).
• The Boiler Cleaning Waste Special Condition was eliminated due to the discontinuation of the
power generation
• The Section 316(a) of CWA Thermal Variance Special Condition was eliminated due to the
discontinuation of the power generation.
• The Section 316(b) of CWA Special Condition was eliminated due to the discontinuation of the
power generation.
• The turbidity limit was added to the permit to meet the state turbidity standard per 15A NCAC
2B .0211(3) (k) (Outfall 002)
• The Technology Based Effluent Limits for Total Arsenic, Total Mercury, Total Selenium, and
Nitrate/mtnte as N were added to the permit and are based on the requirements of 40 CFR
125.3(a) , 40 CFR 122 44(a)(1); 40 CFR 125.3(c) and (d) (Outfall 002 and Outfall 010)
• The Interim Technology Based Effluent Limits (Outfall 002) for Total Arsenic, Total Selenium,
and Nitrate/nitrate as N were added to the permit and are based on the requirements of 40
CFR 125.3(a) , 40 CFR 122 44(a)(1), 125.3(c) and (d)
1617 Mall Service Center, Raleigh, North Carolina 27699-1617
Phone [phone] Internet www ncwaterquality org
An Equal Opportunity 1 Affirmative Action Employer— Made in part by recycled paper

• Proposed federal regulations require electronic submittal of all discharge monitoring reports
(DMRs) and specify that, if a state does not establish a system to receive such submittals, then
permittees must submit DMRs electronically to the Environmental Protection Agency (EPA)
The Division anticipates that these regulations will be adopted and is beginning
implementation.
The requirement to begin reporting discharge monitoring data electronically using the NC
DWR's Electronic Discharge Monitoring Report (eDMR) internet application has been added to
the permit. (Please see Special Condition A. (18.))
The Applicable State Law Special Condition was added to the permit to meet the requirements
of Senate Bill 729 (Coal Ash Management Act, Please see Special Condition A (19.)).
The Outfall 011 (former Stormwater Outfall 1) was added to the permit (Please see A. (20.)).
Please provide any comments you have regarding the draft permit to this office by April
6, 2015. At this time, the Division is also publishing a notice in the newspapers of general circulation
in Gaston County, inviting public comment on the draft permit. Following the 30 -day comment
period, we will review all pertinent comments received and take appropriate action on the permit
renewal.
If you have any questions about the NPDES permit process, please contact me at the following
e-mail address sergei chernikov(a,ncdenr.gov, or telephone number 919-807-6386.
Sincerely,
Sergei Chernikov, Ph.D
G/ Environmental Engineer II
Complex NPDES Permuting Unit
cc Central Files
NPDES Files
EPA Region IV
Mooresville Regional Office / Water Quality (e -copy)
Mooresville Regional Office / Public Water Supply Regional Engineer (e -copy)
WSS/Aquatic Toxicology Unit (e -copy)
1617 Mall Service Center, Raleigh, North Carolina 27699-1617
Phone. [phone] Internet www rimaterquallty org
An Equal Opportunity 1 AffirmatNe Acton Employer — Made in part by recycled paper

Permit NC0004961
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER RESOURCES
Draft PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
In compliance with the provision of North Carolina General Statute 143-215 1, other lawful
standards and regulations promulgated and adopted by the North Carolina Environmental
Management Commission, and the Federal Water Pollution Control Act, as amended,
Duke Energy Carolinas, LLC
is hereby authorized to discharge wastewater from a facility located at the
Riverbend Steam Station
Mount Holly
Gaston County
to receiving waters designated as the Catawba River in the Catawba River Basin
in accordance with effluent limitations, monitoring requirements, and other
applicable conditions set forth in Parts I, II, III and IV hereof.
This permit shall become effective
This permit and authorization to discharge shall expire at midnight on February 28, 2020.
Signed this day
DRAFT
S. Jay Zimmerman, Director
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 15

Permit NC0004961
SUPPLEMENT TO PERMIT COVER SHEET
All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby
revoked. As of this permit issuance, any previously issued permit bearing this number is no longer
effective Therefore, the exclusive authority to operate and discharge from this facility arises under
the permit conditions, requirements, terms, and provisions included herein
Duke Energy Carolinas, LLC is hereby authorized to:
1. Continue to discharge:
Once through cooling water (outfall 00 1) consisting of intake screen
backwash and water from the plant chiller system, turbine lube oil coolers,
condensate coolers, main turbine steam condensers and the intake tunnel
dewatering sump
• Ash basin discharge (outfall 002) consisting of induced draft fan and
preheater bearing cooling water, stormwater from roof drains and paving,
treated groundwater, track hopper sump (groundwater), coal pile runoff,
laboratory drain and chemical makeup tanks and drums rinsate wastes,
general plant/ trailer sanitary wastewater, turbine and boiler rooms sumps,
vehicle rinse water, and stormwater from pond areas, upgradient
watershed, and miscellaneous stormwater flows.
Yard sump overflow (outfall 002A).
12 potentially contaminated groundwater seeps (outfall 010).
Wastewater, stormwater and groundwater (outfall 011).
From a facility located at Riverbend Steam Station, Mount Holly in Gaston
County, and
2. Discharge wastewater from said treatment works at the location specified on
the attached map into the Catawba River, which is classified WS -IV and B -CA
waters in the Catawba River Basin.
Page 2 of 15

Permit NC0004961
Part I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
001) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge once -through cooling water and intake screen backwash from
outfall 001 Such discharges shall be limited and monitored3 by the Permittee as specified below.
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
MonthlyDaily
Average
Maximum
Measurement
Fre uency
Sample Type
Sample
Location'
Flow
Monthly
Pump Logs
Influent or
Effluent
Temperature (OF)
Monthly
Grab
Effluent
Temperature (oF)2
89 6 (32oC)
Monthly
Grab
Downstream
Notes
1 Downstream sampling point downstream at Mountain Island Lake If samples are collected
below the water surface, the Permittee will record the sample depth on the DMR form
2 The ambient temperature shall not exceed 89 60F (32 0°C) and is defined as the daily average
downstream water temperature. When the Riverbend Station effluent temperature is recorded
below 89.60F (32 0°C), as a daily average, then monitoring and reporting of the downstream water
temperature is not required In cases where the Permittee experiences equipment problems and
is unable to obtain daily temperatures from the existing temperature monitoring system, the
temperature monitoring must be reestablished within five working days
3 No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system See Special
Condition A. (18 ).
Chlorination of the once through condenser cooling water, discharged through outfall 001, is
not allowed under this permit. Should Duke Energy wish to chlorinate its condenser cooling
water, a permit modification must be requested and received prior to commencing
chlorination.
There shall be no discharge of floating solids or visible foam in other than trace amounts
Page 3 of 15

Permit NC000496 T
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
002) [15A NCAC 02B.0400 et seq , 02B 0500 et seq ]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 002 — Ash Pond Discharge Such discharges shall be
limited and monitored? by the Permittee as specified below
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly v Daily Measurement Sample Type Sample Location
Average Maximum Frequency
Flow
Weekly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23 0 mg/L
75 0 mg/L
Monthly
Grab
Effluent
Oil and Grease
110 mg/L
15 0 mg/L
Annually
Grab
Effluent
Total Copper2
10 mg/L
10 mg/L
Quarterly
Grab
Effluent
Total Iron2
10 mg/L
10 mg/L
Quarterly
Grab
Effluent
Total Arsenic
52 5 tig/L
72 5 dig/L
Quarterly
Grab
Effluent
Total Selenium
68 0 fig/L
127 5 Ng/L
Quarterly
Grab
Effluent
Nitrate/nitrite as N
0 65 mg/L
0 85 mg/L
Quarterly
Grab
Effluent
Total Arsenic
10 5pg/L8
14 5 pg/L8
Quarterly
Grab
Effluent
Total Selenium
13 6 pg/L8
25 5 Ng/L8
Quarterly
Grab
Effluent
Total Mercury
47 0 ng/L6
47 0 ng/L6
Quarterly
Grab
Effluent
Nitrate/nitrite as N
013 mg/L8
017 mg/L8
Quarterly
Grab
Effluent
Total Phosphorus
Semi-annually
Grab
Effluent
Total Nitrogen (NO2 + NO3 + TKN)
Semi-annually
Grab
Effluent
pH3
Monthly
Grab
Effluent
Chronic Toxicity4
Quarterly
Grab
Effluent
Turbidity5
Monthly
Grab
Effluent
Notes -
1 Monthly average of 43 mg/ L is permitted provided that the Permittee can satisfactorily
demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the concentration of
total suspended solids in the intake water.
2. The limits for total copper and total iron only apply during a chemical metals cleaning.
3. The pH shall not be less than 6 0 standard units nor greater than 9.0 standard units
4 Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 10%. Tests
shall be conducted in January, April, July and October (see Part A (6.) for details).
5 The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50
NTU. If the instream turbidity exceeds 50 NTU due to natural background conditions, the
discharge cannot cause turbidity to increase in the receiving stream
NTU - Nephelometric Turbidity Unit.
6 The facility shall use EPA method 1631E
7 No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system. See Special
Condition A (18 ).
8 Facility is allowed 4.5 years from the effective date of the permit to comply with the TBELs
This time period is provided in order for the facility to budget, design, and construct the
treatment system Permit might be re -opened to implement the final EPA Effluent
Guidelines and more stringent limits might be added.
The metal cleaning waste, coal pile runoff, ash transport water, domestic wastewater,
and low volume waste shall be discharged into the ash settling pond.
No chemicals, cleaners, or other additives may be present in the vehicle wash water
to be discharged from this outfall.
There shall be no discharge of floating solids or visible foam in other than trace
amounts.
Page 4 of 15

Permit NC0004961
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
002) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 002 - Ash Pond Discharge (Dewatering) Such
discharges shall be limited and monitored' by the Permittee as specified below -
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily Measurement Sample Type Sample Location
Average Maximum Frequency
Flow
Weekly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23 0 mg/L
75 0 mg/L
Monthly
Grab
Effluent
Oil and Grease
110 m /L
15 0 mg/L
Annually
Grab
Effluent
Total Copper2
10 mg/L
10 mg/L
Quarterly
Grab
Effluent
Total Iron2
10 mg/L
10 mg/L
Quarterly
Grab
Effluent
Total Arsenic
10 5 pg/L
14 5 Ng/L
Quarterly
Grab
Effluent
Total Selenium
13 6 Ng/L
25 5 pg/L
Quarterly
Grab
Effluent
Total Aluminum
318 mg/L
318 mg/L
Quarterly
Grab
Effluent
Total Mercury
47 0 ng/L6
47 0 ng/Ls
Quarterly
Grab
Effluent
Nitrate/nitrate as N
013 mg/L
017 mg/L
Quarterly
Grab
Effluent
Total Phosphorus
Semi-annually
Grab
Effluent
Total Nitrogen (NO2 + NO3 + TKN)
Semi-annually
Grab
Effluent
pH3
Monthly
Grab
Effluent
Chronic ToxiCity4
Quarterly
Grab
Effluent
Turbidity5
Monthly
Grab
Effluent
Notes:
1 Monthly average of 43 mg/ L is permitted provided that the Permittee can satisfactorily
demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the
concentration of total suspended solids in the intake water
2. The limits for total copper and total .iron only apply during a chemical metals cleaning
3. The pH shall not be less than 6.0 standard units nor greater than 9 0 standard units.
4. Whole Effluent Toxicity shall be monitored by chronic toxicity (Ceriodaphnia) P/F at 10%
Tests shall be conducted in January, April, July and October (see Part A.(6.) for details).
5. The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50
NTU If the instream turbidity exceeds 56 NTU due to natural background conditions, the
discharge cannot cause turbidity to increase in the receiving stream.
NTU - Nephelometric Turbidity Unit.
6. The facility shall use EPA method 1631E
7. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system See
Special Condition A (18.).
The metal cleaning waste, coal pile runoff, ash transport water, domestic wastewater,
and low volume waste shall be discharged into the ash settling pond.
No chemicals, cleaners, or other additives may be present in the vehicle wash water
to be discharged from this outfall.
There shall be no discharge of floating solids or visible foam in other than trace
amounts.
Page 5 of 15

Permit NC0004961'
A. (4.) EFFLUENT LIMITATIONS. AND MONITORING REQUIREMENTS (Outfall
002A) [15A NCAC 02B .0400 et seq , 02B .0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 002A - Yard Sump Overflows Such discharges
shall be limited and monrtored4 by the Permittee as specified below:
EFFLUENT �
CHARACTERISTICS
LIMITS ,
MONITORING REQUIREMENTS
Monthly Daily
Average Maximum
Measurement Sample Type Sample Location'
Frequency
Flow
Episodic
Estimate
Effluent
Total Suspended Solids2
23.0 mg/L
75 0 m /L
Episodic
Grab
Effluent
Oil and Grease2
110 mg/L
15 0 mg/L
Episodic
Grab
Effluent
Fecal Coliform
Episodic
Grab
Effluent
Total Copper3
10 mg/L
10 mg/L
Episodic
Grab
Effluent
Total Iron3
10 mg/L
10 mg/L
Episodic
Grab
Effluent
pH5
Episodic
Grab
Effluent
Notes:
1. Effluent sampling shall be conducted at a point upstream of discharge to the receiving
stream.
2. The monthly average limits for total suspended solids and oil and grease are applicable only if
the overflow occurs for more than 24 hours
3. The limits for total copper and total iron only apply during a chemical metals cleaning
4. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system. See Special
Condition A. (18.).
5. The pH shall not be less than 6 0 standard units nor greater than 9.0 standard units.
THERE SHALL BE NO DISCHARGE OF FLOATING SOLIDS OR VISIBLE FOAM IN OTHER THAN
TRACE AMOUNTS
ALL FLOWS SHALL BE REPORTED ON MONTHLY DMRS. SHOULD NO FLOW OCCUR DURING A
GIVEN MONTH, THE WORDS "NO FLOW" SHOULD BE CLEARLY WRITEN ON THE FRONT OF
THE DMR. EPISODIC SAMPLING IS REQUIRED PER OCCURRANCE WHEN SUMP OVERFLOWS
OCCUR FOR LONGER THAN ONE HOUR. ALL SAMPLES SHALL BE OF A REPRESENTATIVE
DISCHARGE.
Page 6 of 15

Permit NC0004961
A. (5.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
010) [15A NCAC 02B 0400 et seq , 02B 0500 et seq.]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from Outfall 010 (combined seep outfall). Such discharges
shall be limited and monitored' by the Permittee as specified below
EFFLUENT CHARACTERISTICS
DISCHARGE LIMITATIONS
MONITORING REQUIREMENTS
Monthly
Average
Weekly
Average
Daily
Maximum
Measurement
Frequency2
Sample
Type
Sample Location
Total Suspended Solids
30 0 mg/L
100 0 mg/L
Monthly
Grab
Effluent
Total Arsenic
10 5 pg/L4
14 5 pg/L4
Monthly
Grab
Effluent
Total Mercury3
47 0 ng/L4
47 0 ng/L4
Monthly
Grab
Effluent
Total Selenium
13 6 pg/L4
25 5 pg/L4
Monthly
Grab
Effluent
Nitrate/nitrite as N
013 mg/L4
017 mg/L4
Monthly
Grab
Effluent
Flow
Monitor & Report
Monthly
Grab
Effluent
TDS
Monitor & Report
Monthly
Grab
Effluent
Chlorides
Monitor & Report
Monthly
Grab
Effluent
Fluoride
Monitor & Report
Monthly
Grab
Effluent
Total Barium
Monitor & Report
Monthly
Grab
Effluent
Total Iron
Monitor & Report
Monthly
Grab
Effluent
Total Manganese
Monitor & Report
Monthly
Grab
Effluent
Total Zinc
Monitor & Report
Monthly
Grab
Effluent
Total Cadmium
Monitor & Report
Monthly
Grab
Effluent
Total Chromium
Monitor & Report
Monthly
Grab
Effluent
Total Copper
Monitor & Report
Monthly
Grab
Effluent
Total Lead
Monitor & Report
Monthly
Grab
Effluent
Total Nickel
Monitor & Report
Monthly
Grab
Effluent
Temperature
Monitor & Report
Monthly
Grab
Effluent
Specific Conductance
Monitor & Report
Monthly
Grab
Effluent
pH
Between 6 0 and 9 0 standard units
Monthly
Grab
Effluent
NOTES:
1. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system See Special
Condition A (18.)
2. After the first year, the monitoring frequency will be reduced to a semi-annual basis.
3 The facility shall use EPA method 1631E
4. The limits can be met by installation of the treatment system, re-routing the discharge to the
existing treatment system, or discontinuing the discharge
There shall be no discharge of floating solids or visible foam in other than trace amounts.
Page 7 of 15

Permit NC000496I'
A. (6.) CHRONIC TOXICITY PASS/FAIL PERMIT LIMIT (QUARTERLY) (Outfall
002) [15A NCAC 02B 0200 et seq.]
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnia dubia at an effluent concentration of 2.7%
The permit holder shall perform at a minimum,guarterlmonitoring using test procedures outlined
in the "North Carolina Cenodaphnia Chronic Effluent Bioassay Procedure," Revised December 2010,
or subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure"
(Revised- December 2010) or subsequent versions The tests will be performed during the months of
January, April, July, and October These months signify the first month of each three-month
toxicity testing quarter assigned to the facility Effluent sampling for this testing must be obtained
during representative effluent discharge and shall be performed at the NPDES permitted final
effluent discharge below all treatment processes
If the test procedure performed as the first test of any single quarter results in a failure or
ChV below the permit limit, then multiple -concentration testing shall be performed at a
minimum, in each of the two following months as described in "North Carolina Phase II
Chronic Whole Effluent Toxicity Test Procedure" (Revised -December 2010) or subsequent
versions.
All toxicity testing results required as part of this permit condition will be entered on the Effluent
Discharge Monitoring Form (MR -1) for the months in which tests were performed, using the _
parameter code TGP313 for the pass/fail results and THP313 for the Chronic Value Additionally,
DWR Form AT -3 (original) is to be sent to the following address -
Attention North Carolina Division of Water Resources
Water Sciences Section/Aquatic Toxicology Branch
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Water Sciences Section no later than
30 days after the end of the reporting period for which the report is made.
Test data shall be complete, accurate, include all supporting chemical/ physical measurements and
all concentration/ response data, and be certified by laboratory supervisor and ORC or approved
designate signature Total residual chlorine of the effluent toxicity sample must be measured and
reported if chlorine is employed for disinfection of the waste stream.
Should there be no discharge of flow from the facility during a month in which toxicity monitoring is
required, the permittee will complete the information located at the top of the aquatic toxicity (AT)
test form indicating the facility name, permit number, pipe number, county, and the month/year of
the report with the notation of "No Flow" in the comment area of the form The report shall be
submitted to the Water Sciences Section at the address cited above.
Should the permittee fail to monitor during a month in which toxicity monitoring is required,
monitoring will be required during the following month. Assessment of toxicity compliance is based
on the toxicity testing quarter, which is the three month time interval that begins on the first day of
the month in which toxicity testing is required by this permit and continues until the final day of the
third month.
Should any test data from this monitoring requirement or tests performed by the North Carolina
Division of Water Resources indicate potential impacts to the receiving stream, this permit may be
re -opened and modified to include alternate monitor=ng requirements or limits.
NOTE Failure to achieve test conditions as specified in the cited document, such as minimum
control organism survival, minimum control organism reproduction, and appropriate environmental
Page 8of15

Permit NC0004961
controls, shall constitute an invalid test and will require immediate follow-up testing to be
completed no later than the last day of the month following the month of the initial monitoring
A. (7.) BIOCIDE CONDITION
The permittee shall not use any biocides except those approved in conjunction with the permit
application The permittee shall notify the Director in writing not later than ninety (90) days prior to
instituting use of any additional biocide used in cooling systems which may be toxic to aquatic life
other than those previously reported to the Division of Water Resources Such notification shall
include completion of Biocide Worksheet From 101 and a map locating the discharge point and
receiving stream Completion of a Biocide Worksheet 101 is not necessary for the introduction of a
new biocide into an outfall currently being tested for toxicity
A. (8.) SPECIAL CONDITIONS
The following special conditions are applicable to all outfalls regulated by NC0004961
• There shall be no discharge of polychlorinated biphenyl compounds
• The Permittee shall check the diked areas for leaks by a visual inspection and shall report any
leakage detected
• Nothing contained in this permit shall be construed as a waiver by the Permittee or any right to a
hearing it may have pursuant to State or Federal laws or regulations
• Discharge of any product registered under the Federal Insecticide, Fungicide, and Rodenticide Act
to any waste stream which may ultimately be released to lakes, rivers, streams or other waters of
the United States is prohibited unless specifically authorized elsewhere in this permit Discharge
of chlorine from the use of chlorine gas, sodium hypochlorite, or other similar chlorination
compounds for disinfection in the plant potable and service water systems and in sewage
treatment is authorized Use of restricted use pesticides for lake management purposes by
applicators licensed by the N C Pesticide Board is allowed
• The Permittee shall report all visible discharges of floating materials, such as an oil sheen, to the
Director when submitting DMRs
A. (9.) PERMIT TERMS
The following are applicable to all outfalls regulated by NC0004961
• The term "low volume waste sources" means, taken collectively as if from one source, wastewater
from all sources except those for which specific limitations are otherwise established in this part
Low volume wastewater sources include, but are not limited to wastewater from wet scrubber
air pollution control systems, ion exchange water treatment system, water treatment evaporator
blowdown, laboratory and sampling streams, boiler blowdown, floor drains, cooling tower basin
cleaning wastes, and recirculating service water systems. Sanitary and air conditioning wastes
are not included.
• The term "metal cleaning waste" means any wastewater resulting from cleaning (with or without
chemical cleaning compounds) any metal process equipment including, but not limited to, boiler
tube cleaning, boiler fireside cleaning, and air preheater cleaning Chemical metal cleaning will
be conducted according to Duke Energy approved equivalency demonstration
• It has been determined from information submitted that the plans and procedures in place at
Riverbend Steam Station are equivalent to that of a BMP
A. (10.) ASH SETTLING BASIN
Beginning on the effective date of this permit and lasting until expiration, there shall be no discharge
of plant wastewater to the ash pond unless the Permittee provides and maintains at all times a
minimum free water volume (between the top of the sediment level and the minimum discharge
elevation) equivalent to the sum of the maximum 24-hour plant discharges plus all direct rainfall and
all runoff flows to the pond resulting from a 10 -year, 24-hour rainfall event, when using a runoff
coefficient of 1 0. During the term of the permit, the Permittee shall remove settled material from the
ponds or otherwise enlarge the available storage capacities in order to maintain the required
Page 9 of 15

Permit NC000496 Y
minimum volumes at all times The Permittee shall determine and report to the permit issuing
authority the following on an annual basis
1) the actual free water volume of the ash pond,
2) physical measurements of the dimensions of the free water volume in sufficient detail to allow
validation of the calculated volume, and
3) a certification that the required volume is available with adequate safety factor to include all
solids expected to be deposited in the pond for the following year.
Present information indicates a needed volume of 86.2 acre-feet in addition to solids that will be
deposited to the ash pond, any change to plant operations affecting such certification shall be
reported to the Director within five days
NOTE In the event that adequate volume has been certified to exist for the term of the permit,
periodic certification is not needed
A. (11.) GROUNDWATER MONITORING WELL CONSTRUCTION AND SAMPLING
The permittee shall conduct groundwater monitoring to determine the compliance of this NPDES
permitted facility with the current groundwater Standards found under 15A NCAC 2L 0200 The
monitoring shall be conducted in accordance with the Sampling Plan approved by the Division.
A.(12.) STRUCTURAL INTEGRITY INSPECTIONS OF ASH POND DAM
The facility shall meet the dam design and dam safety requirements per 15A NCAC 2K.
A.(13.) FISH TISSUE MONITORING NEAR ASH POND DISCHARGE
The facility shall conduct fish tissue monitoring once during the permit term and submit the results
with the NPDES permit renewal application The objective of the monitoring is to evaluate potential
uptake of pollutants by fish tissue near the Ash Pond discharge. The parameters analyzed in fish
tissue shall be arsenic, selenium, and mercury The monitoring shall be conducted in accordance
with the Sampling Plan approved by the Division.
A.(14.) INSTREAM MONITORING
The facility shall conduct semiannual in stream monitoring (one upstream and one downstream of
the ash pond discharge) for arsenic, selenium, mercury (method 1631E), chromium, lead, cadmium,
copper, zinc, and total dissolved solids (TDS) Instream monitoring should be conducted at the
stations that have already been established through the BIP monitoring program- B (upstream of the
Outfall 002) and C (downstream of the Outfall 002). The monitoring results shall be submitted with
the NPDES permit renewal application.
A.(15.) ASH POND CLOSURE
The facility shall prepare an Ash Pond Closure Plan in anticipation of the facility closure This Plan
shall be submitted to the Division one month prior to the decommissioning of the pond
A.(16.) PRIORITY POLLUTANT ANALYSIS
The Permittee shall conduct a priority pollutant analysis (in accordance with 40 CFR Part 136) once
per permit cycle at outfall 002 and submit the results with the application for permit renewal
A.(17.) SEEP POLLUTANT ANALYSIS
Seeps with locations identified in Appendix A are classified collectively as Outfall 010. The facility
shall continue to implement the Plan for Identification of New Discharges (see Appendix B) to
determine if new seeps have emerged
Seeps are ephemeral in nature and enter the river at various changing locations. Seeps entering the
river from the upstream edge of permittee's property to the downstream property boundary shall be
calculated as if entering at one location
Page 10 of 15

Permit NC0004961
Permittee shall conduct seep identification survey semi-annually to determine if new seeps have
started or that previously identified seeps have significantly changed in size or flow New seeps
identified through the seep survey or otherwise discovered or reported to the permittee shall have
their flow calculated, be sampled for parameters indicated with results and location(s) reported to
Division of Water Resources within 5 days of detection (location only, sampling results shall be
submitted within 30 days of sampling) for administrative inclusion in Appendix A
Newly identified seeps or seeps whose flow increases will not be considered as new outfalls or
wastestream requiring modification of the permit as long as total flow of all seeps does not exceed 0 5
million gallons per day (MGD) and pollutant characterization is similar to previously identified seeps
identified in Table 1 and formation of seep(s) or increase in flow was not caused by change in
operations by permittee If the pollutant sampling concentration of a new seep exceeds the
concentrations in Table 1 the Division will calculate reasonable potential and determine if either
administrative inclusion of the seep or formal modification of the permit is necessary Permittee will
be notified by the Division within 30 days of receiving the sampling results if permit modification is
necessary
The maximum allowable parameter concentration in Table 1 is determined by multiplying the highest
baseline seep concentration levels by 10
Table 1. Seep Monitoring Parameters and Screening Values
Parameter
Maximum allowable
parameter
concentration
Maximum allowable
total flow for all
existing and future
seeps
Chlorides
73 0 mg/L
0 5 MGD
Fluoride
10 0 mg/L
0 5 MGD
Total Mercury (Method
1631E) '
47 0 ng/L
0 5 MGD
Total Barium
1 0 mg/L
0 5 MGD
Total Iron
65 1 m /L
0 5 MGD
Total Manganese
12 3 mg/L
0 5 MGD
Total Zinc
190 0 pg/L
0 5 MGD
Arsenic'
14 5 µg/L
0 5 MGD
Total Cadmium
10 0 µ /L
0 5 MGD
Total Chromium
10 0 µ /L
0 5 MGD
Total Copper
15 8 µg/L
0 5 MGD
Total Lead
25 0 pg/L
0 5 MGD
Total Nickel
87 7 pg/L
0 5 MGD
Selenium'
25 5 µ /L
0 5 MGD
Nitrate/Nitrite as N'
0 17 mg/L
0 5 MGD
H
60-90
05MGD
TDS
500 0 m L
0 5 MGD
TSS
75 0 mg/L
0.5 MGD
Temperature
monitor
0 5 MGD
Specific Conductance
monitor
0 5 MGD
Notes
1 Technology Based Effluent Limits. The limits can be met by installation of the treatment
system, re-routing the discharge to the existing treatment system, or discontinuing the
discharge
A. (18.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
(State Enforceable Only) [G.S. 143-215 1(b)]
Proposed federal regulations require electronic submittal of all discharge monitoring reports (DMRs)
and specify that, if a state does not establish a system to receive such submittals, then permittees
must submit DMRs electronically to the Environmental Protection Agency (EPA). The Division
anticipates that these regulations will be adopted and is beginning implementation in late 2013.
Page 11 of 15

Permit NC000496 r
NOTE This special condition supplements or supersedes the following sections within Part II of this
permit (Standard Conditzons for NPDES Permits).
• Section B (11 ) Signatory Requirements
• Section D
(2.)
• Section D
(6 )
• Section E
(5.)
Reporting
Records Retention
Monitoring Reports
1. Reporting [Supersedes Section D. (2.) and Section E. 15.1 (a)l
Beginning no later than 270 days from the effective date of this permit, the permittee shall begin
reporting discharge monitoring data electronically using the NC DWR's Electronic Discharge
Monitoring Report (eDMR) internet application_
Monitoring results obtained during the previous month(s) shall be summarized for each month
and submitted electronically using eDMR The eDMR system allows permitted facilities to enter
monitoring data and submit DMRs electronica=ly using the internet Until such time that the
state's eDMR application is compliant with EPA's Cross -Media Electronic Reporting Regulation
(CROMERR), permittees will be required to submit all discharge monitoring data to the state
electronically using eDMR and will be required to complete the eDMR submission by printing,
signing, and submitting one signed original and a copy of the computer printed eDMR to the
following address:
NC DENR / DWR / Information Processing Un_t
ATTENTION: Central Files / eDMR
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the
facility being physically located in an area where less than 10 percent of the households have
broadband access, then a temporary waiver from the NPDES electronic reporting requirements
may be granted and discharge monitoring data may be submitted on paper DMR forms (MR 1,
1. 1, 2, 3) or alternative forms approved by the Director Duplicate signed copies shall be
submitted to the mailing address above.
Requests for temporary waivers from the NPDES electronic reporting requirements must be
submitted in writing to the Division for written approval at least sixty (60) days prior to the date
the facility would be required under this permit to begin using eDMR Temporary waivers shall
be valid for twelve (12) months and shall thereupon expire At such time, DMRs shall be
submitted electronically to the Division unless the permittee re -applies for and is granted a new
temporary waiver by the Division
Information on eDMR and application for a temporary waiver from the NPDES electronic
reporting requirements is found on the following web page
http: / /-portal.ncdenr.org/web/wq/admin/­bog/ipu/­edmr
Regardless of the submission method, the first DMR is due on the last day of the month following
the issuance of the permit or in the case of a new facility, on the last day of the month following
the commencement of discharge.
Page 12 of 15

Permit NC0004961
2. Signatory Requirements [Supplements Section B. (11.) (b) and supersedes Section B. (11.)
All eDMRs submitted to the permit issuing authority shall be signed by a person described in
Part II, Section B (11 )(a) or by a duly authorized representative of that person as described in
Part II, Section B (11 )(b) A person, and not a position, must be delegated signatory authority
for eDMR reporting purposes.
For eDMR submissions, the person signing and submitting the DMR must obtain an eDMR user
account and login credentials to access the eDMR system For more information on North
Carolina's eDMR system, registering for eDMR and obtaining an eDMR user account, please visit
the following web page.
http //-portal ncdenr.org/web/wq/admin/bog/ipu/edmr
Certification Any person submitting an electronic DMR using the state's eDMR system shall
make the following certification 140 CFR 122.22] NO OTHER STATEMENTS OF CERTIFICATION
WILL BE ACCEPTED
'7 certify, under penalty of law, that this document and all attachments were prepared under my
direction or supervision in accordance with a system designed to assure that qualified personnel
properly gather and evaluate the information submitted Based on my inquiry of the person or
persons who manage the system, or those persons directly responsible for gathering the
information, the information submitted is, to the best of my knowledge and belief, true, accurate,
and complete I am aware that there are significant penalties for submitting false information,
including the possibility of fines and imprisonment for knowing violations. "
3. Records Retention [Supplements Section D. (6.)1
The permittee shall retain records of all Discharge Monitoring Reports, including eDMR
submissions These records or copies shall be maintained for a period of at least 3 years from
the date of the report This period may be extended by request of the Director at any time [40
CFR 122 41]
A. (19.) APPLICABLE STATE LAW (State Enforceable Only)
This facility shall meet the requirements of Senate Bill 729 (Coal Ash Management Act) This permit
may be reopened to include new requirements imposed by Senate Bill 729.
Page 13 of 15

Permit NC000496I-
A. (20.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS (Outfall
011) [15A NCAC 02B 0400 et seq , 02B 0500 et seq ]
During the period beginning on the effective date of this permit and lasting until expiration, the
Permittee is authorized to discharge from outfall 011 — Former Stormwater Outfall 1 Such
discharges shall be limited and momtored5 by the Permittee as specified below:
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily
Average Maximun
Measurement Sample Type Sample Location
Frequency
Flow
Monthly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23 0 mg/L
75 0 mg/L
Monthly
Grab
Effluent
Oil and Grease
110 mg/L
15 0 mg/L
Annually
Grab
Effluent
Total Arsenic
Quarterly
Grab
Effluent
Total Selenium
Quarterly
Grab
Effluent
Total Mercur 6
Quarterly
Grab
Effluent
Nitrate/nitrate as N
Quarterly
Grab
Effluent
Total Phosphorus
Semi-annually
Grab
Effluent
Total Nitrogen (NO2 + NO3 + TKN)
Semi-annually
Grab
Effluent
pH3
Monthly
Grab
Effluent
Turbidity4
Monthly
Grab
Effluent
Notes
1 Monthly average of 43 mg/L is permitted provided that the Permittee can satisfactorily
demonstrate that the difference between 23 mg/L and 43 mg/L is a result of the
concentration of total suspended solids in the intake water
2. The limits for total copper and total iron only apply during a chemical metals cleaning.
3 The pH shall not be less than 6 0 standard units nor greater than 9 0 standard units.
4 The discharge from this facility shall not cause turbidity in the receiving stream to exceed 50
NTU. If the instream turbidity exceeds 50 NTU due to natural background conditions, the
discharge cannot cause turbidity to increase in the receiving stream.
NTU - Nephelometric Turbidity Unit
5. No later than 270 days from the effective date of this permit, begin submitting discharge
monitoring reports electronically using NC DWR's eDMR application system. See
Special Condition A (18 )
6 The facility shall use EPA method 1631E.
There shall be no discharge of floating solids or visible foam in other than trace
amounts.
Page 14 of 15

Permit NC0004961
Appendix A
The permittee has identified 12 potentially contaminated seeps in the areas adjacent to the Mountain
Island Lake The locations of the seeps are identified on the map attached to the permit Existing and
newly identified seeps shall be sampled on a monthly basis for the first 12 months After the first
year the monitoring frequency will be reduced to a semi-annual basis
Seep Coordinates and Assigned Outfall Numbers
Seep ID
Latitude
Longitude
Outfall number
S-1
35.365
-80.967
101
S-2
35.365
-80.966
102
S-3
36 369
-80.965
103
S-4
35.371
-80.963
104
S-5
35.370
-80.963
105
S-6
35.367
-80.958
106
S-7
35 367
-80957
107
S-8
35 365
-80956
108
S-9
1 35 371
-80963
109
5-10
35 369
-80960
110
5-11
35 369
-80960
111
5-12
35 368
-80959
112
Plan for Identification of New Discharges
Appendix B
Page 15 of 15

Duke Energy Corporation
Riverbend Steam Station
State Grid/Quad:
F15SW/Mt. Island Lake, NC
Receiving Streams:Catawba River Sub -Basin: 03-08-33
Stream Class:
WS -IV & B -CA Permitted Flow: Not limited
Drainage Basin:
Catawba River Basin
Latitude (001):
35021'28" N Longitude (001): 80° 58' 12" W
Latitude (002):
350 22'06" N Longitude (002): 80° 57'31" W
Latitude (002A):
35'21'51" N Longitude (002A): 80° 58' 11" W
Latitude (011):
35° 21'38" N Longitude (011): 80° 58' 38" W
Map not to scale
Facility
Location
North NPDES Permit No. NC0004961
Gaston Coup