NC0004961_Issuance of Permit_20110118

M1
NC® NR
North Carolina Department of Environment and Natura
Division of Water Quality
Beverly Eaves Perdue
Governor
Mr Allen Stowe
Water Management,
Duke Energy Corporation, P O Box 1006
Charlotte, North Carolina 28201
Dear Mr Stowe:
Coleen H Sullins
Director
January 18, 2011
6NJ & #11, t7.11
Resources
Subject NPDES Permit Issuance
Permit No NC0004961
Riverbend Steam Station
Gaston County
f
Dee Freeman
Secretary
The Division of Water Quality is forwarding herewith the Final NPDES permit for Riverbend Steam Station. This permit
renewal is issued pursuant to the requirements of North Carolina General Statute 143-215.1 and the Memorandum of
Agreement between North Carolina and the U S Environmental Protection Agency dated October 15, 2007 (or as
subsequently amended).
A public hearing was held on October 19, 2010 in Mooresville seeking comments on the Draft permit and proposed
continuation of the Clean Water Act Section 316(a) temperature variance This Final permit incorporates recommendations of
the DWQ Hearing Officer as well as other changes Listed below are all changes from the previous permit
• Structural integri , inspection of ash pond dam. Dam safety and design requirements per 15A NCAC 2K are
required.
• CWA Section 316(x) Thermal Variance. This condition requires the facility to submit a Balanced and Indigenous
Population (BIP) study plan that conforms to EPA study guidelines, and receives DWQ and EPA concurrence prior
to study implementation A BIP report must be submitted no later than 180 days prior to permit expiration, should
the permittee request continuation of the CWA Section 316(a) thermal variance
• Fish Tissue Monitoring Near Ash Pond Discharge The facility shall conduct fish tissue monitoring near the ash pond
discharge, once during the permit term, and analyze for arsenic, selenium, and mercury. The fish tissue monitoring
shall be in accordance with the Sampling Plan approved by the Division
• Instream Monitoring The facility shall conduct semiannual instream monitoring at two BIP monitoring stations
(located upstream and downstream of the ash pond discharge) Samples shall be analyzed for arsenic, selenium,
mercury, chromium, lead, cadmium, copper, zinc, and total dissolved solids (TDS)
• Quarterly effluent monitoring for mercury was added to Outfall 002
1617 Mail Service Center, Raleigh, North Carolina 27699-1617
Location 512 N Salisbury St Raleigh, North Carolina 27604 One
Phone [phone] FAX [phone] Customer Service 1-877-623-6748 NorthCarohna
Internet www ncwaterqualityprg � 1�N� //�
An Equal Opportunity 1 Affirmative Action Employer Nal ` l

• Ash Pond Closure The facility shall prepare an Ash Pond Closure Plan in anticipation of the facility closure This'
' ll
Plan shall be submitted to the Division one year prior to the closure of the facility n
• Monitoring frequency for Oil and Gr9ase has been reduced to annually based on DMR data and as,a response to yo4
request.
• Monitoring frequency for TSS has been reduced to monthly based on DMR data and as a response to your request
• Groundwater monitoring was added to the permit. Please see Special Condition A (11 )
If any parts, measurement frequencies, or samohng requirements contained in this permit are unacceptable to you, you have
the right to an adjudicatory hearing upon written request within thirty (30) days following receipt of this letter This request
must be in the form of a written petition, conforming to Chapter 150B of the North Carolina General Statutes, and filed with
the office of Administrative Hearings, 6714 Mail Service Center, Raleigh, North Carolina 27699-6714. Unless such a demand
is made, this permit shall be final and binding
Please take notice that this permit is not transferable except after notice to the Division of Water Quality. The Division may
require modification,or revocation and reissuance ofthe permit This permit does not affect the legal requirements to. obtain _ T
other permits which may be required by the D=vision of Water Quality, the Division of Land Resources, the Coastal Area
Management Act, or any other federal or local governmental permit
If you have any questions on this permit, please contact Sergei Chernikov at 919-807-6393.
Sincerely,
aeenulliris
Hardcopy Central Files, NPDES Files
Mooresville Regional Office, SWPS
NPDES files
Email US EPA, Region IV
Aquatic Toxicology Unit
Kay Bond, Southern Environmental Law Center [kbond@selcnc org]
David Merryman, Catawba Riverkeeper, [david@catawbariverkeeper org]
Hope Taylor, CWFNC [hope@cwfnc org]
1617 Mad Service Center, Raleigh, North Carolina 27699-1617
Location 512 N Salisbury St Raleigh, North Carolina 27604 One
Phone [phone] \ FAX [phone] \ Customer Service 1-877-623-6748 NorthCarolina
Internet www ncwaterquahty org N� //�
An Equal Opportunity 1 Affirmative Action Employer A��u` "

STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
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
conditions set forth in Parts I, II, III and IV hereof.
This permit shall become effective March 1, 2011.
This permit and authorization to discharge shall expire at midnight on February 28, 2015.
Signed this day January 18, 2011.
Co en H. Sullins, Ifirecior
Division of Water Quality
By Authority of the Environmental Management Commission

Permit NC000496.1
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 0
• 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,
ash transport water, general plant/trailer sanitary wastewater, metal
cleaning waste, chemical metal cleaning waste, combustion turbine -cooling
water discharges, turbine and boiler rooms sumps, vehicle rinse water,
and stormwater from pond areas and upgradient watershed
• Yard sump overflow (002A)
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.
• 2 1 1

Duke Energy Corporation
Riverbend Steam Station
State Grid/Ouad: 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):
350 21' 28" N
Longitude (0011:(0011:
8C° 58' 12" W
Latitude (002)•
350 22' 06" N
Longitude (0021:(0021:
80° 57' 31" W
Latitude (002A)•
350 21'51 " N
Longitude (002A): 80° 58' 11" W
Map not to scale
Facility
Location
t:"":ts.--
North
NPDES Permit No. NC0004961

Permit NC0004961
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
During the period beginning on the effective date of this permit and lasting until expiration, the Permittee is
authorized to discharge from outfall 002 Such discharges shall be limited and monitored by the Permittee as
specified below -
EFFLUENT CHARACTERISTICS
41
Monthly
Average
LIMITS
Daily
Maximum
MONITORING REQUIREMENTS
Measurement Sample Type Sample Location
Frequency 6
Flow
Weekly
Pump logs or
estimate
Influent or Effluent
Total Suspended Solids'
23 0 m /L
75 0 m /L
Month)
Grab
Effluent
Oil and Grease
110 m /L
15 0 m /L
Annual)
Grab
Effluent
Total Co ere
10 m /L
10 m /L
Quarterly
Grab
Effluent
Total Iron2
10 m /L
10 m /L
Quarterly
Grab
Effluent
Total Arsernc2
Quarterly
Grab
Effluent
Total Selemum2
Quarterly
Grab
Effluent
Total Mercury
Quarterly
Grab
Effluent
Total Phosphorus
Semi-annually
Grab
Effluent
Total Nitrogen NO2 + NO3 + TKN
Semi-annually
Grab
Effluent
H3
Monthly
Grab
Effluent
Chronic Toxnt 4
Quarterly
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. Total metals are defined by 40 CFR 136. Any method specified by 40 CFR 136 is considered
acceptable for analysis.
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 (Ceriodaphma) P/F at 10%. Tests
shall be conducted in January, April, July and October (see Part A.(4.) for details)
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.
0

Permit NC0004961
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
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 monitored by the Permittee as specified below
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily
Average Maximum
Measurement Sample Type 4 Sample Location'
Frequency
Flow
Daily
Pump Logs
Influent or Effluent
Temperature of
95 0 35-C)
Daily.
Grab
Effluent
Temperature (of)2
89 6 32-C
Daily
Grab
Downstream
Temperature (OF)3
Daily
Grab
Effluent
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 OOC) and is defined as the daily average downstream
water temperature When the Rrverbend Station effluent temperature is recorded below 89 60F (32 OoC), 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. This temperature requirement is in effect when only units with a shared control system are
operating.
1 If the daily average intake temperature is below 36.50F (2 50C), the daily average effluent temperature
shall not exceed 50 OoF (100C), and .
2. If the daily average intake temperature ranges from 36 5oF (2 50C) to 55 OoF (12 80C), the daily average
effluent temperature shall not exceed two times the intake temperature (OF) minus 23
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.
3

Permit NC0004961
A. (3.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
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
monitored by the Permittee as specified below
EFFLUENT
CHARACTERISTICS
LIMITS
MONITORING REQUIREMENTS
Monthly Daily Measurement Sample Type Sample Location
Average Maximum Frequency
Flow
Episodic
Estimate
Effluent'
H
Eisodic
Grab
Effluent
Total Suspended Solids2
23 0 m /L
75 0 m /L
Episodic
Grab
Effluent
Oil and Grease2
110 m /L
15 0 m /L
Eisodic
Grab
Effluent
Fecal Coliform
Eisodic
Grab
Effluent
Total Co era
10 m /L
10 m /L
Eisodic
Grab
Effluent
Total Iron3
10 M917
10 m /L
Eisodic
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.
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 WRITER 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.
5

Permit NC0004,961 "
A: (4.)` CHRONIC TOXICITY PASS/FAIL-PERMIT LIMIT (QUARTERLY)
The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant
mortality to Ceriodaphnta dubaa at an effluent concentration of 10%.
The permit holder shall perform at a minimum, quarterlmonitoring using test procedures outlined
in the "North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure," Revised February 1998,
or subsequent versions or "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure"
(Revised -February 1998) or subsequent versions. The tests will be performed during the months
of January, April, July and October. Effluent sampling for this testing 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 -February 1998) or subsequent versions.
The chronic value for multiple concentration tests will be determined using the geometric mean of the
highest concentration having no detectable impairment of reproduction or survival and the lowest
concentration that does have a detectable impairment of reproduction or survival. The definition of
"detectable impairment," collection methods, exposure regimes, and further statistical methods are
specified in the "North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised -
February 1998) 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 THP3B for the Chronic Value. Additionally, DWQ
Form AT -3 (original) is to be sent to the following address:
Attention:North Carolina Division of Water Quality
Environmental Sciences Section
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
Completed Aquatic Toxicity Test Forms shall be filed with the Environmental 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 Environmental 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. Should any test data from this monitoring requirement or tests
performed by the North Carolina Division of Water Quality indicate potential impacts to the receiving
stream, this permit may be re -opened and modified to include alternate monitoring requirements or
limits. If the Permittee monitors any pollutant more frequently then required by this permit, the
results of such monitoring shall be included in the calculation & reporting of the data submitted on
the DMR & all AT Forms submitted.
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
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.

Permit NIC0004961
A. (5.) 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 nay additional biocide used in cooling systems which may be toxic to aquatic life
other than those previously reported to the Division of Water Quality. 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 anew biocide
into an outfall currently being tested for toxicity.
A. (6.) 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 wasters
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. (7.) 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. (8.) 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
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
7

Permit NC0004.96,1
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. (9.) BOILER CLEANING WASTES
It has been demonstrated that unde- certain conditions it is possible to reduce the concentration of
metals in boiler cleaning wastes in the range of 92-99+ percent by treatment in ash ponds. Because
of dilution problems and the existence of boundary interface layers at the extremities of the plume, it
is difficult to prove beyond doubt that the quantity of iron and copper discharge will always be less
than one milligram per liter times the flow of metal cleaning when treated in this manner.
- The application of physical/ chemical methods of treating wastewater has also been demonstrated to
be effective in the treatment of metal cleaning wastes However, the effectiveness of ash pond
treatment should be considered in relation to the small differences in effluent quality realized
between the two methods
It has been demonstrated that the presence of ions of copper, iron, nickel and zinc in the ash pond
waters was not measurably increased during the ash pond equivalency demonstration oat the Duke
Energy's Riverbend Steam Station Therefore, when the following conditions are implemented during
metal cleaning procedures, effective treatment for metals can be obtained at this facility:
1 Large ash basin providing potential reaction volumes in the ratio of 100 to 1
2. Well-defined shallow ash delta near the ash basin influent
3. Ash pond pHs of no less than 6.5 prior to metal cleaning waste addition.
4. Four days retention time in ahs pond with effluent stopped.
5. Boiler volume less than 86,000 gallons.
6. Chemicals for cleaning to include only one or more of the following:
a Copper removal step- sodium bromate (NaBr02), ammonium carbonate ((NH4)2CO3-H20,
and ammonium hydroxide (NH40H)
b. Iron removal step — hydrochloric acid (HCl), ammonium bifluoride ((NH4)HF2 and
proprietary inhibitors
7. Maximum dilution of wastewater before entering ash pond: 6 to 1.
8. If monitoring of basin effluents (as required by the permit) after treatment of metal cleaning
wastes reveals discharges outside the limits of the permit, Permittee will:
1) re -close the basin discharge,
2) conduct such in -basin sampling as necessary to determine the cause of
nonconformance,
3) take appropriate correc=ive actions, and
4) file a report with EPA including all pertinent data.
A.(10.) SECTION 316 (B) OF CWA
The permittee shall comply with the Cooling Water Intake Structure Rule per 40 CFR 125 95.
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.) CWA SECTION 316(A) THERMAL VARIANCE
The thermal variance granted under Section 316(a) terminates on expiration of the NPDES permit Should the
permittee wish a continuation of its 316(a) thermal variance beyond the term of this permit, reapplication for
such continuation shall be submitted in accordance with 40 CFR Part 125, Subpart H and Section 122 21(1)(6)
not later than 180 days prior to permit expiration Reapplication shall include a basis for continuation such as
a) plant operating conditions and load factors are unchanged and are expected to remain so for the term of the
reissued permit, b) there are no changes to plant discharges or other discharges in the plant site area which
8 .. - — 11

Permit NC0004961
could interact with the thermal discharges; and c) there are no changes to the biotic community of the receiving
water body which would impact the previous variance determination -
i'
The next 316 (a) studies shall be performed in accordance with the Division of Water Quality approved plan The
temperature analysis and the balanced and indigenous study plan shall conform to the specifications outlined
in 40 CFR 125 Subpart H and the EPA's Draft 316a Guidance Manual, dated 1977 The EPA shall be provided
an opportunity to review the plan prior to the commencement of the study
A.(14.) 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.(15.) INSTREAM MONITORING
The facility shall conduct semiannual in stream monitoring (one upstream and one downstream of the ash pond
discharge) for arsenic, selenium, mercury, 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 The monitoring results shall be submitted with the NPDES permit renewal application
A.(16.) 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 year prior to the closure of the facility.
A.(17.) 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
9

,A]PM e�Nd Afe T4 "'A"
Aa; --
Beverly Eaves Perdue
Governor
Date:
To:
From:
Subject:
NC®ENR
North Carolina Department of Environment and
Division of Water Quality
Coleen H. Sullins
nirartnr
January 12, 2011
Coleen Sullins, Director
Division of Water Quality
Art Barnhardt, Hearing O*
Natural Resources
Duke Energy- Marshall, Riverbend & Allen Steam Stations
NPDES Permits NC0004987, NC0004961, NC0004979
Coal Fired Steam Power Generation Facilities
Catawba River Basin, Gaston & Catawba Counties
Dee Freeman ,
Secreta
140
�A rJ�^ rX tN= G
V
v'�C vtl.�.
Please find submitted with this transmittal memo, the report for the Public Hearing
associated with the subject 3 NPDES permit renewals. Please advise if any of the
information submitted needs clarification as you consider these permit actions.
Thank you for the opportunity to have served in this role for the State of North
Carolina and the citizens that rely on DWQ to protect the water quality
r+lX � p.l�af'� fNl &te MivzkAJA"�
/V Cn(7 yi $ /
AQUIFER PROTECTION SECTION
1636 Mail Service Center, Raleigh, North Carolina 27699-1636
Location 2728 Capital Boulevard, Raleigh, North Carolina 27604
Phone [phone] l FAX [phone], FAX [phone] V Customer Service 1-877-623-6748
Internet www ncvaatergualif orq
An Equal Opportunity 1 Affirmative Action Employer
NorthCarolEna
Aaturally

HEARING OFFICER REPORT
for
Renewal of NPDES Permits and Continuation of 316(a) Temperature
Variances
Duke Energy (Marshall, Riverbend, and Allen Steam Stations)
This report is presented to the Director of the North Carolina Division of the Water Quality
INTRODUCTION
On September 15, 2010 a notice of Public Hearing was published in the Charlotte Observer and
Hickory Daily Record, requesting public comment on Draft NPDES Permit renewals and proposed
Clean Water Act (CWA) Section 316 (a) temperature variance continuations for three Duke Energy
facilities (i.e., Marshall Steam Station, Riverbend Steam Station, and Allen Steam Station) located in
the Catawba River Basin. The public notice also provided information on a public hearing to be held
to solicit additional comment
A public hearing was held on October 19, 2010, at the Charles Mack Citizen Center in Mooresville,
NC. Oral and written comments became part of the public record, which was closed at the end of
the hearing. Art Barnhardt with the Division of Water Quality's Fayetteville Regional Office served
as the Hearing Officer.
This Hearing Officer Report summarizes the mayor issues raised through the public hearing process,
as well as the Hearing Officer recommendations for the NPDES permit renewals and CWA 316(a)
temperature variances The Director of the Division of Water Quality will take final action on these
recommendations
1

FACILITY BACKGROUNDS
Duke Energy/Marshall Steam Station (NPDES Permit# NC0004987)
Duke Energy's Marshall Steam Station is a coal fired steam electric plant in Catawba County This
facility discharges wastewater to Lake Norman (classified Water Supply) in the Catawba River Basin.
Lake Norman is not listed on the 2010 303(d) list of impaired waters. The facility discharges
wastewater via five permitted outfalls: Outfall 001 (Condenser Cooling Water); Outfall 002 (Ash
basin); Outfalls 002a&b (yard sump overflows); and Internal Outfall 004 (flue gas desulfurization
(FGD) treatment system discharge to ash basin). The facility has an FGD scrubber, dry fly ash
handling system, one active ash pond, one active landfill for FGD waste, and one inactive coal ash
landfill. The facility submitted a Balanced and Indigenous (BIP) report in support of its CWA 316 (a)
temperature variance continuation, and the BIP report was reviewed and approved by the Division's
Environmental Sciences Section (ESS).
Duke Enerev/Rlverbend Steam Station (NPDES Permit# NC0004961)
Duke Energy's Riverbend Steam Station is a coal fired steam electric plant in Gaston County. The
facility discharges wastewater to Mountain Island Lake (classified Water Supply) in the Catawba
River Basin. Mountain Island Lake is not listed on the 2010 303(d) list of impaired waters. The
facility discharges wastewater via three permitted outfalls: Outfall 001 (Condenser Cooling Water);
Outfall 002 (ash basin); and Outfall 002a (yard sump overflows). Duke Energy plans to close this
peak load facility down by 2015, therefore they have not installed an FGD scrubber system. The
facility currently operates two active ash ponds. The facility submitted a Balanced and Indigenous
(BIP) report in support of its CWA 316 (a) temperature variance continuation, and the BIP report was
reviewed and approved by the Division's Environmental Sciences Section (ESS).
Duke Energy/Allen Steam Station (NPDES Permit# N000049791
Duke Energy's Allen Steam Station is a coal fired steam electric plant in Gaston County. The facility
discharges wastewater to the Catawba River and South Fork Catawba River (both classified Water
Supply) in the Catawba River Basin. The Catawba River near the discharge point is listed on the 2010
303(d) list as impaired, while the South Fork Catawba River is not listed as impaired. The facility
discharges wastewater via seven permitted outfalls: Outfall 001 (Condenser Cooling Water); Outfall
002 (ash basin); Outfalls 002a&b [yard sump overflows); Outfalls 003 and 004 (miscellaneous non -
contact cooling water); and Internal Outfall 005 (flue gas desulfurization (FGD) treatment system
discharge to the ash pond). The facility has an FGD scrubber, a dry fly ash handling system, one
active and one inactive ash pond, and oneactive landfill for FGD waste and coal ash. The facility
submitted a Balanced and Indigenous (BIP) report in support of its CWA 316 (a) temperature
variance continuation, and the BIP report was reviewed and approved by the Division's
Environmental Sciences Section (ESS).
2

a
PUBLIC RECORD
The Division held a public hearing in Mooresville NC on October 19, 2010. Approximately 74 people
attended the public hearing and about 20 attendees provided oral comments. Attendees and
speakers included representatives from Duke Energy, Mecklenburg County, several environmental
interest groups and concerned citizens. Overall, the Division received 160 written comments.
Each facility discharges heated water via Outfall 001, and ash basin wastewater via Outfall 002.
Primary issues raised through the permit process include potential impacts to aquatic life due to the
heated water discharge, and potential impacts to aquatic life and human health due to the
discharge of ash pond wastewater.
Listed below is a summary of issues raised, and Division staff response to those comments.
1) Effluent Monitoring. There were several requests for more frequent and more expansive
effluent monitoring, particularly for metals from Outfall 002 (ash pond discharge).
Response: Frequency of monitoring and number of parameters that are being monitored
are based on results of the reasonable potential analysis (RPA). If a parameter shows
reasonable potential and requires a limit, monitoring is generally at a monthly or quarterly
frequency. If a parameter does not show reasonable potential, monitoring might drop to
quarterly or not be required. Monthly discharge monitoring reports (DMRs) and priority
pollutant scans (required with each permit renewal) are evaluated for RPA with each
renewal. The proposed monitoring frequencies will provide adequate information to
conduct RPAs for the next permit renewal. The contaminants that have received the most
attention with coal ash discharge include arsenic, mercury, and selenium. These core
parameters are in the Draft permit monitoring requirement for Outfall 002 (with the
exception of mercury at Duke Riverbend), and will be retained regardless of RPA results.
Based on public concern, DWQ staff recommends that quarterly effluent monitoring for
mercury be added to Outfall 002 (ash pond discharge) for the Duke Riverbend Final Permit,
which will result in all three facilities maintaining a core monitoring for arsenic, selenium,
and mercury in their effluent..
2) Effluent Limits. There were several requests for addition of effluent permit limits for all
metals at Outfall 002 (ash pond discharge).
Response: The need for water quality based effluent permit limits is determined according
to a reasonable potential analysis (RPA). The RPA procedure utilized by the Division is in
3

accordance with EPA's regulation at 40 CFR 122.44(d)(1). Permit limits are added only if the
results of the RPA suggest potential for exceeding the water quality standards, and are not
arbitrarily assigned. However, absence of permit limits does not allow the facility to violate
in stream water quality standards.
3) Fish tissue monitoring. There were several requests for the addition of fish tissue
monitoring requirements to the permits, particularly near Outfall 002 (ash pond discharge).
Response: Although the facilities are not currently required to conduct fish tissue
monitoring, Duke Energy has conducted fish tissue monitoring in the past in both Lake
Norman (near Duke Marshall) and Mountain Island Lake (near Duke Riverbend).
Selenium, arsenic, mercury, and zinc concentrations were measured in common carp,
sunfish, and bass collected by electrofishing in July (2004 — 2008) at four locations in
Mountain Island Lake. Trace element concentrations have been measured in Mountain
Island Lake common carp, sunfish, and bass since 1988. Trace element concentrations from
2004 to 2008 remained well below values of regulatory concern, where such values exist.
Limited fish sampling in Lake Norman was also conducted in 2009. Approximately 25 bass
were sampled for selenium and mercury. Concentrations were 0.55 mg/kg and 0.11 mg/kg,
and both were below the recommended NC DHHS criteria of 10 mg/kg (selenium) and 0.4
mg/kg (mercury). Based on public concern, DWQ staff recommends that a fish tissue
monitoring event (once/permit cycle) be added to all three permits. Fish tissue should be
analyzed for arsenic, selenium, and mercury, with details of the monitoring to be
established by ESS biologists.
4) Instream monitoring. There were several requests to add instream monitoring to the
permits.
Response: Facilities are required to conduct biological studies to support renewal of the
CWA 316(a) temperature variance. These BIP (balanced and indigenous population) studies
include instream monitoring as an integral part of evaluation. Each facility has 6-7
permanent instream monitoring stations, and a few additional temporary stations. DWQ
biologists establish monitoring plans for the biological studies and review the results. Based
on public concern, DWQ staff recommends the addition of semiannual instream monitoring
(upstream and downstream) for arsenic, selenium, mercury, 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.
4

5) Total Dissolved Solids (TDS). There were several requests for addition of a 500 mg/L
effluent limit for TDS
Response: There is a water quality standard for TDS (500 mg/I) for water supply waters,
which includes the subject receiving waterbodies. Duke Energy measured TDS in the ash
ponds for all three powers plants. The results are: Allen — 740 mg/L, Marshall — 730 mg/L,
Riverbend —100 mg/L. Based on the available dilution (instream waste concentrations are
10% at Riverbend, 17% at Marshall, and 20% at Allen), it is unlikely that the instream water
quality standard for TDS would be violated. Actual monitoring in the lakes conducted during
2000 through 2009 indicates that TDS values are well below 100 mg/L. Based on public
concern, DWQ staff recommends the addition of semiannual instream monitoring
(upstream and downstream) for TDS (refer to Response to Comment #4 above).
6) Total Suspended Solids (TSS) and Turbidity. There were several requests for increased
monitoring and/or more stringent permit limits for TSS. Additionally, the Catawba
Riverkeeper provided a picture of Lake Norman (near Marshall Steam Station) with a darker
color plume apparently emanating from the Outfall 001 cooling water discharge, contending
that this plume is a result of high TSS/turbidity in the discharge.
Response: US EPA sets Effluent Limitations Guidelines for TSS (per 40 CFR 423) for fly
ash/bottom ash; thus these permits incorporate TSS limits at the coal ash pond discharge
(Outfall 002). EPA requirements do not set TSS limitations for once through cooling water
(Outfall 001), and these permits are consistent with that decision. Monthly monitoring for
TSS at the ash pond discharges (Outfall 002) is considered adequate based on the historical
data. Long-term monitoring data indicates very low concentration of TSS in the discharge
from these power plants, usually within 5-10 mg/L.
During summer, Lake Norman is subject to thermal stratification. The Marshall Station
withdraws cooling water from a depth of approximately 60 feet, to ensure compliance with
the temperature limit and for greater power plant efficiency. This deep layer of water
contains reduced forms of iron and manganese, which are formed due to the lack of oxygen.
This phenomenon is similar to formation of dissolved iron and manganese in the
groundwater. When this water from the deep layer of Lake Norman is exposed to the
oxygen on the surface, iron and manganese are oxidized and water becomes discolored.
This plume cannot be attributed to the turbidity of the discharge or TSS concentration. The
maximum concentration of TSS in the cooling water discharge of the Marshall Steam Station
during the previous permit cycle was only 4 mg/L.
61,

7) Temperature Variance. There were several comments that the existing CWA 316(a)
temperature variances are not protective enough and DWQ should implement daily
maximum temperature limits instead of monthly average limits.
Response: Continuation of the CWA 316(a) temperature variance is predicated on a positive
demonstration of balanced and indigenous macro! nvertebrate and fish community in the
receiving waterbodies. The Division's Biological Assessment Unit reviewed the biological
reports and concurred with the BIP conclusions. Therefore, the alternative temperature
limits in the Draft Permit are considered to provide adequate protection for aquatic life.
8) Arsenic exceedences near Riverbend Outfall 002 (ash pond discharge). Both Mecklenburg
County and the Catawba Riverkeeper indicated that some surface water samples collected
near the Riverbend ash pond discharge showed concentrations of arsenic above the water
quality standard of 10 ug/L.
Response: The NC regulations (15A NCAC 2B.0206) allow for dilution provided by upstream
flow (either 7Q10, 30Q2, or mean annual flow) when establishing effluent permit
limitations. This approach is consistent with EPA guidance (US EPA 1991, Technical Support
Document for Water Quality -Based Toxics Control). Dilution may not occur instantaneously,
thus there is an implicit mixing zone near the point of discharge where water quality
standards might be exceeded. Surface water sampling indicates that these exceedences are
very infrequent. Surface water samples collected approximately 0.5 miles downstream from
the discharge in the main stem of the Catawba River show 32 out of 39 samples were below
the detection level for arsenic, and the maximum arsenic value was 3.6 ug/L, which is well
below the water quality standard of 10 ug/L. In addition, surface water sampling conducted
at the City of Charlotte's drinking water intake during the same time period showed all
samples (n= 22) below the arsenic detection level.
9) Mixing Zone. There were several comments submitted requesting delineation of mixing
zones in the permits.
Response: As indicated in Response to Comment 8 above, state regulations provide for an
implicit mixing zone based on consideration of upstream dilution, and this was incorporated
into development of metals limits. Evaluation of a mixing zone for temperature is a special
case subject to CWA Section 316(a) requirements. Since all three facilities have a CWA
316(a) temperature variance, they are required to conduct BIP studies. If these biological
studies demonstrate the existence of a positive BIP, then the temperature variance can be
continued and mixing zone delineations are not necessary.
M

10) Coal ash pond closure. There were several requests for a permit requirement to develop an
Ash Pond Closure Plan, including clean-up, lining, and closure of ash ponds.
Response: EPA is currently developing new regulations for coal ash disposal. Most of the
ash disposal requirements will fall under the purview of the Division of Waste Management,
and it is still uncertain at this time what final regulations will be adopted.
11) Implement proposed water quality standards from Triennial Review. There was one
request for the permits to reflect proposed water quality standa rd changes from the current
Triennial Review, including copper, zinc, and nickel.
Response: The Triennial Review has not been finalized and approved by the EMC and EPA.
The approval process might cause significant changes in the proposed standards.
Therefore, it is premature for DWQ to implement these standards into permit limits at this
time.
12) Technology/FGD wastewater treatment. There was one request for installation of a zero
discharge Flue Gas Desulfurization (FGD) treatment system for the Marshall Steam Station.
Response: An FGD treatment system is already installed at Duke Marshall, and it would be
extremely expensive to retrofit it with the new technology. It is also difficult to install a zero
discharge system on an existing plant. EPA is currently re-evaluating its Effluent Limitations
Guidelines for the Steam Electric Point Source Category (40 CFR 423), and the Division will
review and incorporate any new federal requirements for FGD discharges once EPA
completes its regulatory process.
13) Technoloev/Dry cooling system. There was one request for installation of dry cooling
systems to avoid hot temperature discharges.
Response: EPA reviewed dry cooling technologies and concluded that they are very
inefficient and expensive. They require more coal to generate the same amount of energy.
Therefore, they were not recommended for implementation in the 316(b) Phase II rule.
Even the cooling towers, which are less expensive and more efficient than dry cooling
systems, are not currently required by regulation. In addition, BIP studies indicate no
impact on the receiving lakes. Therefore, DWQ does not believe that there is a need for dry
cooling systems.
7

14) Miscellaneous wastes. There was one request for addition of a new permit requirement to
report volumes and types of miscellaneous wastes to be identified and reported by the
permittee.
Response: Federal anc state rules do not contain such a requirement. In addition, the
miscellaneous wastes that are discharged to the ash pond represent an extremely small
percentage of the overall discharge flow. The existing monitoring and reporting
requirements are considered sufficient.
15) Arsenic and mercury in water treatment residuals, There was one comment from the City
of Gastonia expressing concerns about the amount and source of arsenic and mercury found
in their water treatment plant sludge. They requested a scientific evaluation to determine
the source(s) of these elements in the sludge.
Response: Discharges from power plants contribute to the overall mercury and arsenic
loading. Monitoring of the ash pond discharge and surface water indicates that
concentrations of mercury and arsenic in the discharge and the lakes are within a safe
range.
16) Forced Evaporation/Surface Water Loss. There was one request that the permit process
should consider the impact of forced evaporation upon the State water supply.
Response: This request is outside the purview of the NPDES program.
17) Climate change. There was one request that the permits should take climate change into
account.
Response: This request is outside the purview of the NPDES Program.
N.

Findings and Observations of the Hearing Officer
After consideration of input from the public, Duke Energy, DWQ staff and results of past
environmental and water quality monitoring data generated it is quite evident that all the
participants in the hearing process have a high level of interest in maintaining the water quality
within this section of the Catawba River Basin. Duke Energy has good historical record of
compliance over the most recent NPDES permit cycle. Utilization of the water resources to help
meet the consumer energy demands, as is done at these three Duke Energy facilities, cannot be
achieved with zero impact. Therefore the permits and temperature variances being considered
through this hearing process are the means to control the impacts to the levels required by State
and Federal regulations. As a result, the public comment process did identify several permit
improvement issues where minor changes will be recommended for incorporation in the permits.
Effluent monitoring, effluent limits (including TDS & TSS):
Some public comment recommended additional effluent monitoring and lower effluent limits. The
inferred reasoning is to protect water quality to a higher standard due to the cumulative impact of
the Duke Energy Facilities along with the many other water quality impacting activities within the
basin. Additionally, one person at the public hearing testified as having some skepticism in allowing
the Duke Facilities to self -monitor effluent and in stream water quality indicators. The Hearing
Officer does not share this skepticism, but is interested in reporting to the Director of DWQ the
perceptions of the public that invested the time and effort to attend the forum.
Since self-monitoring is a standard practice at nearly all NPDES permitted facilities it is important for
all stakeholders to have a high level of confidence in the data being generated. Compliance
monitoring inspections are a part of the DWQ oversight effort and are geared to enhance the quality
control and quality assurance of this important environmental compliance activity. While not
proposing any changes to the draft NPDES permits to address this specific issue, it is a
recommendation to the Director that DWQ staff partner with stakeholders to obtain ideas on
possible ways to structure DWQ compliance sampling inspections that would build confidence in the
self-monitoring data output.
In the opinion of the Hearing Officer, the regulatory NPDES permitting processes by which effluent
monitoring and limits are established have been properly applied by the DWQ permitting staff. It is
also the Hearing Officer's opinion that the monitoring requirements for core parameters (mercury,
arsenic, selenium should be consistent for all 3 permits.
0

Fish Tissue Monitoring and In Stream Water Quality:
Tissue analysis for target indicators is one of many ways to measure overall water quality by
examination of the various fish aopulations within a water body. Some previous work has been
accomplished by Duke Energy (and others) where the results have Indicated generally acceptable
tissue conditions. While tissue monitoring is not required as part of the ongoing BIP studies, it is
information that can complement the BIP results and produce a more comprehensive view of the
resource status.
The same reasoning applies to in stream water quality monitoring. Conducting water quality
analyses at the BIP station locations for effluent related constituents may not be necessary to
evaluate the indigenous species populations and diversities but it would also be a good complement
to the long term water quality monitoring effort and likewise would provide a better view of the
resource condition. It is the Hearing Officer's opinion that collection of this additional
environmental data would be valuable and easy to accomplish by Duke Energy.
Discharge of Non -Contact Cooling Water
The thermal discharge was a topic discussed with the 2 main concerns; first, the NC Water Quality
Standard (15A NCAC 02B .0211(31(1)) should apply without allowing the variance under (15A NCAC
02B .0208 (b) m and second, the Impact that warmed water has on forced evaporation rates.
It is the opinion of the Hearing Officer that Duke Energy has made the demonstration through BIP
Studies, results of which have been evaluated by DWQ Biological Assessment Unit, that allow for the
continued CWA 316(a) temperature variance. In relation to forced evaporation, it is a fact that
there is higher evaporation potential with increased temperature. The scope of the NPDES
Permitting Program does not include regulatory authority to account for loss of water through
forced evaporation. However it is an important Catawba River Basin dynamic that the Hearing
Officer feels the Director or DWQ should be appraised of in order to factor into future resource
management decisions that will arise as our finite water resource use continues to rise.
Arsenic above Water Quality Standard of 10 ug/I near Riverbend Outfall 002 and Mixing tones
The zone of water in the area adjacent to an outfall, before effluent has the ability to mix with the
receiving waters, is known as the mixing zone which is defined in 15A NCAC 0213.0202 DEFINITIONS
(44). Although none of the mixing zones around any of the Duke Energy outfalls has been officially
delineated, the arsenic sample locations referred to in the Public Hearing were in such close
proximity to the outfall it is with little doubt within this zone. By rule, water quality standards do
not apply within a mixing zone except as defined in 15A NCAC 02B.0204 (b)1-4.Other water quality
data collected from locations (further from the outfall) in the water body such as the BIP Study
sample locations indicate acceptable arsenic concentrations. It is the Hearing Officer's opinion that
10

although established delineated mixing zones would create a precise boundary in which to measure
in stream water quality compliance, it would not be significantly different than the current
configuration of the BIP monitoring stations or alter the ability of the State to enforce water quality
regulations within the Catawba Basin adjacent to these 3 Duke Energy facilities.
Storage Structure (Dike) Inspections
The draft permits contain the requirement for Duke Energy to inspect the ash pond dikes.
Comments from the hearing indicated the need to specify an inspection schedule and record
keeping requirement. Many of the DWQ Permits (Non-NPDES) containing storage structures specify
inspection frequency and record keeping requirements. Similarly, it is the Hearing Officer's opinion
that outlining the inspection frequency and record keeping requirements would be a beneficial
addition to the permit language.
Groundwater Monitoring Comments
The draft permits contains new groundwater monitoring requirements. The comments made during
the open record were in support of the addition of these requirements. It is the Hearing Officer's
opinion that no changes to this proposed portion of the draft permit are in necessary.
Other Water Resource Related Comments
Several comment topics provided during the open record discussed issues of importance related to
protection of the water resource, but are beyond the regulatory oversight of these NPDES Permit
renewals. They consisted of coal ash pond closure, implementing water quality standards from
triennial review, requiring new technology for FDG wastewater treatment, requiring new cooling
technology, factoring in climate change and developing a drinking water contingency plan in case of
an ash pond failure. It is the Hearing Officer's opinion that these issues are not within the scope of
the NPDES Permitting process and have been given proper consideration.
Hearing Officer Recommendations
Based on review of the public record and written/oral comments received during the public hearing
process, I recommend to the Division Director that the three Duke Energy Draft NPDES Permits
(Duke Energy- Marshall, Riverbend, Allen) be revised and issued with the following minor changes
and continuation of 316(a) Temperature Variances:
11

I- Quarterly effluent monitoring for mercury should be added to Outfall 002 (ash pond
discharge) for the Duke Riverbend Final Permit.
2 -Fish tissue monitoring event (once/permit cycle) be added to all three permits. Fish tissue
should be analyzed for arsenic, selenium, and mercury, with details of the monitoring to be
established by ESS biologists.
3 -Addition of semiannual in stream monitoring (upstream and downstream) for arsenic,
selenium, mercury, chromium, lead, cadmium, copper, zinc, and total dissolved solids (TDS). In
stream monitoring should be conducted at the stations that have already been established
through the BIP monitoring program.
4 -Addition of a specified storage structure (dikes) inspection frequency consisting of weekly and
after any 1 inch or greater rainfall events. A record of the inspection shall also be kept on file
and should consist of :late, time and person that conducted the inspection.
Steph A. Barnhardt, Hearing Of -icer Date
12

APPENDICES
A. Draft Permits and Fact Sheets
B Announcement of the Public Hearing
C. Presentation from the Public Hearing
D. Hearing Registration Sheets
13

APPENDICES
A. Draft Permits and Fact Sheets
B. Announcement of the Public Hearing
C. Presentation from the Public Hearing
D. Hearing Registration Sheets
13

Chernikov, Sergei
From: Stowe, Allen [Allen Stowe@duke-energy com]
Sent: Friday, July 23, 2010 12 43 PM
To: Chernikov, Sergei, Belnick, Tom, Vmzani, Gil
Subject: RE request for further info for NPDES review
Sergei,
Here are our comments regarding this certification request by EPA:
At your request, which we understand comes from EPA's inquiry, we have provided estimates of
the composition of sump overflows derived from predictive calculations, using assumptions as
to the degree of dilution afforded by storm flows and constituents from potential sources of
stormwater contamination.
We would like to point out that sump overflows have been very rare, and would be even more
rare since improvements have been made to the sumps. As the sumps are now configured, an
overflow would occur only as a result of extreme precipitation events during which there was
multiple failures of pumps or motors. Even when sump overflows have occurred in the past,
they have been of very brief duration and a low flow, such that it has not been feasible to
collect a representative sample of such overflows, especially in light of the varied sampling
requirements for the Form 2C parameters.
Because a sump overflow could occur only during a period of extreme precipitation and the
resulting storm flow, there is no way to project with confidence the concentrations of
constituents in the flow, and, therefore, no way to certify the accuracy of the projection.
In fact, a sump overflow would be a "bypass" subject to the provisions of 40 CFR 122.44(m).
The outlets provided for sump overflows were installed to prevent severe damage to motors
which power the pumps within the sump. If these outlets were not provided, the motors would
be inundated, requiring replacement or substantial repair, and thus resulting in potentially
long periods during which the sumps would cease to properly operate. This is no different
than any variety of relief mechanisms for POTWs and other treatment systems which may be used
to avoid comparable damage to treatment or collection systems that would require extended
periods to replace or repair, resulting in environmental damage far more significant than the
bypass would cause. There is no requirement in NC or EPA rules for certification of
predictions of constituent concentrations or loads in hypothetical bypasses. Duke Energy
would, of course, comply with the provisions of 40 CFR 122.41(m) in the event of a sump
overflow.
If you have any comments or concerns, please let me know.
Thanks
Allen Stowe
EHS Water Management
Duke Energy Carolinas
704-382-4309 (Office)
704-516-5548 (Cell)
[e-mail]
-----Original Message -----
From: Chernikov, Sergei[mailto:[e-mail]]
Sent: Friday, July 09, 2010 3:30 PM
To: Stowe, Allen; Belnick, Tom; Vinzani, Gil
1

Ja�Seo srtT�s
UNITED STATES ENVIRONMENTAL. PROTECTION AGENCY
y -P yw REGION 4
o Q ATLANTA FEDERAL CENTER
F o= 61 FORSYTH STREET
~114 PROS,G1 ATLANTA, GEORGIA 30303-8960
JUL 2 8 7010
Ms. Coleen H Sullins
Director, Division of Water Quality
North Carolina Department of Environment
and Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Re: Draft Permit Review
Duke Energy Corporation -- Rrverbend Power Plant
NPDES Permit No. NC0004961
Dear Ms. Sullins:
On June 3, 2010, the Environmental Protection Agency (EPA) Region 4 sent a letter to
the North Carolina Department of Environment and Natural Resources (NCDENR) stating we
had an interim objection to the issuance of the National Pollutant Discharge Elimination System
permit for Duke Energy's Riverbend Power Plant. The facility's permit application did not
include a Form 2C for outfalls 002A and 002B for yard sump overflows. On July 7, 2010,
NCDENR transmitted the required Form 2C application to Ms. Karrie-Jo Shell of my staff via
email. We have completed our review and have no further comments on the draft permit. EPA
requests that we be afforded an additional review opportunity only if significant changes are
made to the permit prior to issuance, or if significant public comments objecting to the issuance
of this permit are received. Otherwise, please send us one copy of the final permit.
If you have any questions, please call me at [phone] or contact Ms. Shell at
[phone].
Sincerely,
James D Giattnia
Director
Water Protection Division
cc: Mr Allen Stowe
Manager, Duke Power Company
Internet Address (URL) • http //www epa.gov
Recycled/Recyclable • Pnnted with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)
� �
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1 JUL 30 2010 ,
F'C}Rt•� i 4n�;F.,E. Sl�..�+i�!t,Fi
Internet Address (URL) • http //www epa.gov
Recycled/Recyclable • Pnnted with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)

JED s'%,S
A UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 4
o Q ATLANTA FEDERAL CENTER
ZyF �o= 61 FORSYTH STREET
+,,4 PRO1,7 ATLANTA, GEORGIA 30303-8960
JUL 282010
Ms. Coleen H. Sullins
Director, Division of Water Quality
North Carolina Department of Environment
and Natural Resources
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Re: Draft Permit Review
Duke Energy Corporation — Riverbend Power Plant
NPDES Permit No. NC0004961
Dear Ms. Sullins:
On June 3, 2010, the Environmental Protection Agency (EPA) Region 4 sent a letter to
the North Carolina Department of Environment and Natural Resources (NCDENR) stating we
had an interim objection to the issuance of the National Pollutant Discharge Elimination System
permit for Duke Energy's Riverbend Power Plant. The facility's permit application did not
include a Form 2C for outfalls 002A and 002B for yard sump overflows. On July 7, 2010,
NCDENR transmitted the required Form 2C application to Ms. Karrie-Jo Shell of my staff via
email. We have completed our review and have no further comments on the draft permit. EPA
requests that we be afforded an additional review opportunity only if significant changes are
made to the permit prior to issuance, or if significant public comments objecting to the issuance
of this permit are received. Otherwise, please send us one copy of the final permit.
If you have any questions, please call me at [phone] or contact Ms. Shell at
[phone].
Sincerely,
James D. Giattina
Director
Water Protection Division
cc: Mr. Allen Stowe
Manager, Duke Power Company
Internet Address (URL) • http Hwww.epa.gov
Recycled/Recyclable . Pnnted with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)

North Carolina SS
Mecklenburg County)
The Charlotte Observer Publishing Co.
Charlotte, NC
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Delaware, and publishing a newspaper known as The
Charlotte Observer in the city of Charlotte,
County of Mecklenburg, and State of North Carolina)
and that as such he/she is familiar with the
books, records, files, and business of said
Corporation and by reference to the files of said
publication, the attached advertisement was
inserted. The following is correctly copied from
the books and files of the aforesaid Corporation
and Publication.
PUBLISHED ON: 09/17
ZJECTPUBLIC NOTICE
The North Carolina Environmental Management
Dommission proposes to issue the following NPDES wastewater
iischarge permits, and is inviting public comment on the draft
oermits Additionally, a public hearing has been scheduled to
orovide additional opportunity for comments
Duke Energy Corpp Riverbend Steam Station (Gaston County),
NPDES Permit #N00004961
Duke Energgy Corp. Allen Steam Station (Gaston County), NPDES
Permit #NC0004979
Duke Energy Corp , Marshall Steam Station (Catawba County),
NPDES Permit #NC0004987 ,
PURPOSE On the basis of preliminary staff review and
application of Article 21 of Chapter 143, General Statutes of North
Carolina, and other lawful standards and regulations, the North
Carolina Environmental Management Commission proposes to
reissue NPDES permits for these facilities subject to specific
pollutant limitations and special conditions and to continue the
316(a) temperature variances The Director of the Division of
Water Quality pursuant to NCGS 143 215 1(c)(3) and Regulation
15 NCAC 2H, Section 0100 has determined that it is in the public
i interest that a hearing be held to receive all pertinent public
i comment on whether to issue, modify, or deny the permits
PROCEDURE Written comments on the draft permits will be
accepted until the date of the Public Hearing Any person or
organization desiring to make oral comments should register to
do,so at the hearing The time available for oral comments may be
limited by the Hearing Officer Oral presentations that exceed
three minutes should be accompanied by three written copies
The hearing record may be closed at the conclusion of
'jthe hearing
WHEN Tuesday, October 19, 2010 at 7 00 p m
(Registration begins at 6 00 p m)
WHERE Charles Mack Citizen Center
215 North Main Street
Mooresville, North Carolina 28115
INFORMATION A copy of the draft NPDES permits can be
downloaded from the following link
htto //notal ncdenroro/web/wa/swo/os/nodes/calendar
The draft permits are also available by writing or calling
Ms bora Sprinkle
NO Division of Water Quality/
NPDES Unit
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
Telephone number [phone]'„
The application and other Information are on file at the Division of
( Water Quality, 512 North Salisbury Street, Room 925 of the
Building
Northart15
MooesviReCona OffiRaleigh,610 Et CenterAvenue, Suite 301
Mooresville, N
28115) They may be inspected during normal
office hours Copies of the information on file are available upon
request and payment of the costs of reproduction All such
j comments and requests regarding this matter should make
reference to the permit numbers NC0004961, NC0004979, and
r NC0004987
LP6503249 °
AD SPACE: 130 LINE
FILED ON: 09/23/10
di I ------------
NAME: TITLE:
DATE: 3 2-010
In Testimony Whereof I have hereunto set my hand and affixed my seal, the
day and 17ear aforesaid.
Notary: mission Expires:
My Commission EA(pires May 27 2011

WDEON
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen FI Sullins Dee Freeman
Governor Directoi Secretary
Alt
Memorandum � 1
To. Coleen Sullins
Thru: Matt Matthews ✓1"�
Thru• Jeff Poupart�j� ('6
From. Tom Belnic 'TG__
Date. June 23, 2010
Re- Request for NPDES Public Hearing, Duke Coal Plants
NPDES received requests for public hearing for three draft permits for Duke Energy coal plants (Allen.
Marshall, Riverbend) in the Catawba River Basin. All three NPDES permits were public noticed on the same
date, and we received similar public comments. There were 19 requests for public hearing for Riverbend/Allen,
and 16 requests for Marshall. Public hearing requests were received from three environmental groups (Clean
Water for NC, Upper Watauga R>verkeeper, Catawba Riverkeeper) as well as 16 individuals. We also received
comments requesting permit changes (but no public hearing request) from Southern Environmental Law Center,
Charlotte -Mecklenburg Storm Water Services, Lake James Environmental Association, and Sierra Club A
summary of comments for Duke Allen is attached. The primary concerns are the 316(a) temperature variance,
as well as coal ash pond issues (metals, structural integrity, pond liner/closure). All three receiving waterbodies
(Lake Norman, Lake Wylie, Mountain Island Lake) are classified as Water Supply.
There are no outstanding NPDES compliance issues related to the current permits, but the public comments
reflect current local and nationwide attention on coal ash. Given the high profile of this issue, NPDES
recommends that a public hearing be held, and the permits be grouped for a single hearing Please let us know
whether to proceed to public hearing
161 / Mad Service Cerate Raleigh, North Caroh )a 2760J9 ?617
LocK tion 512 i! Sall bury Ct Raie;gn Hort; Carohna 2760 0110 n 1
Phone [phone] `t FA7 J19 507-6197_' CuStcrrer Srwicr 1-517-623 6745 Nort l Carol iia
In,ernet my v n waterquality ory J 3all
8 f )a i gy
,.r f ,t I cpp, rt u,d, i irm ha' ,chcl, E'.4 1"" r �/ 1 41

Comments from MRO regarding new draft permits for Allen, Marshall, and Riverbend
Comments from Wes and Donna following inspections at Allen and Marshall Steam stations
on 6/7 and 6/8 (clarification given by Marcia):
They need a stormwater permit. (None of the Duke facilities have individual stormwater
permits Since stormwater is mentioned in two of the permits already should the permit
become a combined wastewater/stormwater permit for all discharges of stormwater?)
o Marshall — no mention of stormwater discharges in NC0004987
o Allen — Stormwater is mentioned as a discharge through Outfall 002 in
NC0004979)
o Riverbend — Stormwater is mentioned as a discharge through Outfall 002 in
NC0004961
Sampling should be more than quarterly, ideally weekly.
o (This is sampling at Outfall 002 [final effluent] and applies to both facilities that
were inspected)
Sampling should be composite, if it can't be flow proportional, then at least time based.
o (This is sampling at Outfall 002 [final effluent] and applies to both facilities that
were inspected- this comment would also apply to Riverbend (M Allocco
comment) From inception of permit (1977 copy available at MRO) until 1989
samples except for Oil & grease were composite samples No information in
permit files (fact sheets, staff reports, etc.) detailing why the change was made.
In the 2001 version of the permit all parameters except Oil & Grease and TSS,
and sulfate are composite samples 2002 permit notes that the monitoring has
been changed from composite to grab due to the large size and consistent
effluent out of the ash basin, grab sampling is considered to be equally
representative of the discharge (how was this determination made?)
Sumps outfalls (2a/b) should be sealed off, but if not they should be sampled regardless
of the length of the discharge event (no hour limitation) and, yes, they can be easily
sampled. (Sampling was conducted using the telescoping sampling pole owned by
MRO)
o Depending on the analysis results for samples collected by MRO staff there may
be a need to add more analytes to the sampling requirements MRO will forward
to permitting the results of the analyses at Marshall and Allen
Facilities should have dual classification.
o Marshall is currently classified as PC -1, should be PC -1 and WW -1 as per D.
Hood communication to M Allocco
o Allen is currently classified as PC -1; should be PC -2 and WW -2 as per D Hood
communication to M. Allocco
o Classification of Riverbend was not reviewed, currently PC -1
Use TPH, not oil and grease, if petroleum is a cause of concern
Comments from Marcia
Riverbend
Section A (5) Biocide Condition — Line 3 "any" is misspelled as "nay"
Section A (5) Biocide Condition - This section states that a biocide worksheet is not
needed when introducing a new biocide to an outfall being currently tested for toxicity Is
this an adequate test of toxicity? The quarterly toxicity testing is a grab sample once a

quarter and would not correspond to the detailed review by DWQ personnel a biocide
sheet submission would afford
Section (6 ) Special Conditions bullet #1 states, "There shall be no discharge of
polychlonnated bi phenyl compounds " From a compliance standpoint how do we
assure this? Is it through the one analysis completed for permit renewal? What is the
inspector to review?
Section (6.) Special Conditions bullet #3 states, "If the permittee, after monitoring for at
least six months, determines that he/she is consistently meeting the effluent limits
contained herein, the permittee may request of the Director that the monitoring
requirement be reduced to a lesser frequency " While this text has appeared in the
permit since 1977 (oldest permit at MRO) I question whether 6 months of data is enough
to determine if a constituent is absent from a discharge Is this the timeframe given to all
permittees or something special tc power plants? If it is not consistent with DWQ
procedures and other permits then it should be changed Should there be a caveat that
any changes to a treatment system or chemicals used in a treatment system the
frequency will be increased
Section (6 ) Special Conditions bullet #5 "waters" is misspelled as "wasters"
Section (6 ) Special Conditions bullet #5 states, "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 " At what level is the chlorine discharge authorized? We are making all other
permittees meet a 50 µg/L TRC compliance level with permit limits of either 17 µg/l- or
28 µg/L This includes Water Treatment Plants that chlorinate the water they provide
and then dechlonnate or otherwise strip chlorine before discharge
Section (6 ) Special Conditions bullet #5 states, "Use of restricted use pesticides for lake
management purposes by applicators licensed by the NC Pesticide Board is allowed."
The EPA has dust promulgated regulations that require a permit when pesticides are
applied to waters of the US I assume this requirement may be permitted by DWQ but it
might also be given to the NC Pesticide Board Need to ensure we are not providing
conflicting authorizations and we may not know for —2 years
Section (7.) Permit Terms bullet #2 states, "Chemical metal cleaning will be conducted
according to Duke Power approved equivalency demonstration " The Duke Power
approved equivalency demonstration was submitted at some point in the past and is
stored in the permit files This does not give the inspector anything to verify when
inspecting the plant
Section (7 ) Permit Terms bullet #3 states, "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." What does this statement refer to? Somewhere between
1980 and 1984 the following caveat was removed from the permit general text and may
be what this statement refers to If so, the language in this bullet needs to be tightened
to require the plans and procedure be updated on a specific schedule and available for
review by DWQ inspectors or is this something that is more appropriate in a stormwater
permit? To me it implies that this is currently a wastewater/stormwater permit "The
Permittee shall develop and implement a Best management practices (BMP) Plan to
identify and control the discharge of oils and the Hazardous and toxic substances listed
in 40 CFR, part 117 and Tables II and II of Appendix D to 40 CFR, Part 122. The plan
shall include a listing of all potential sources of spills or leaks of these materials, a
method for containment, a description of training, inspection and security procedures,
and emergency response measures to be taken in the event of a discharge to surface
waters Sources of such discharges may include but are not limited to, materials storage

areas, in -plant transfer, process and material handling areas, loading and unloading
operations, plant site runoff, and sludge and waste disposal areas The BMP plan shall
be developed in accordance with good engineering practices, shall be documented in
narrative form, and shall include any necessary plot, plans, drawings, and maps The
BMP Plan shall be developed no later than six months after issuance of the final permit
(or modification), and shall be implemented no later than one year after issuance of the
final permit (or modifications) The BMP Plan shall be maintained at the plant site and
shall be available for inspection by EPA and DEM personnel."
Section (8 ) Special Condition for Discharge of Wastewater discusses the need for Duke
to ensure there is adequate room in the ash basin for the solids and associated water
generated at the plant along with stormwater runoff It requires annual reporting to DWQ
unless Duke can certify before issuance of the permit they have adequate room for the
life of the permit However, the following statement in this section is unclear or
confusing "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." Does this statement
mean that Duke needs to clear out 86 2 acre-feet before the permit is issued; need to
clarify language? They must notify us within 5 days of what, first knowledge of the
change in the plant operations? Since the ash basins are now high -hazard dams
inspected by DLR does DLR have a say in how much solids and water are maintained in
the pond
Section (9.) Special Condition — Boiler Cleaning Wastes third paragraph "at" is
misspelled as "oat" and in Item #4 "has" has been misspelled as "ahs".
Section A. (2 ) Effluent Limitations and Monitoring Requirements for Outfall 001 — Note
#1 states, "Downstream sampling point down stream at Mountain Island lake." This
does not describe where in Mountain Island Lake the downstream sample should be
collected Should this be worded "downstream at Mountain Island Lake dam"
Section A. (2 ) Effluent Limitations and Monitoring Requirements for Outfall 002 - Note
#2 under the table states, "Total metals are defined by 40 CFR 136 Any method
specified by 40 CFR is considered acceptable for analysis." This is too vague of a
statement 40 CFR 136 allows for atomic absorption analysis of metals that will only
obtain a detection limit in the mg/L range Although Duke is analyzing via ICP -MS this
statement allows them to backtrack and use a method with a lower detection limit
Although I doubt this will happen we should tighten up our requirements; either require a
specific method such as ICP -MS or require that they detect below the applicable water
quality standard.
Section A (2.) Effluent Limitations and Monitoring Requirements for Outfall 002 - there is
no monitoring for mercury at Outfall 002 Since all waters within North Carolina are
impaired for mercury due to fish tissue concentrations (not noted in the fact sheet) Duke
should have to monitor for mercury especially since coal-fired power plants are a mayor
source of mercury in the environment They should be required to use Method 1631 E
with a detection limit of 12 ng/L
Due to the recent release of monitoring data for Mountain Island Lake from the Catawba
Riverkeeper the permit should not be released until the data has been reviewed It is
unclear whether the Duke data collected during the 316(a) variance request can be
compared to the Riverkeeper's data Duke is only performing sediment analyses on
sediment fines and it appears the Riverkeepr's results are for all sediment within a
sediment core We need to be able to compare The 2004 study by Duke appears to
show an increase in arsenic in sediment directly down stream of the cove where Outfall
002 discharges (their statement) No data in MRO files regarding 316(a) data since

h
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
�� YW REGION 4
o Q ATLANTA FEDERAL CENTER
Z3F �o= 61 FORSYTH STREET
74 PROSEG� ATLANTA, GEORGIA 30303-8960
rJUti 0 3 2010
Collen H. Sullins 1E C E � V E pT(,-Zg%9 D
Director, Division of Water QuaR
North Carolina Department of E enlrid ���� SUN ®� 2010
Natural Resources LL��II
1617 Mail Service Center OF Wp,TES OFFICE
Raleigh, North Carolina 27699 16 7 DENR - WATER QUALITY oN. OFCTOR'
URFACE WATER PROTECTION SECTION
Dear Ms. Sullins:
EPA, Region 4 is in receipt of the draft National Pollutant Discharge Elimination System
(NPDES) permit for the Riverbend Power Plant. The permit application information did not
include a Form 2C for outfall 002A — yard sump overflows, which has an intermittent discharge
to waters of the US. The information regarding the effluent characteristics for this outfall is
required by 40 Code of Federal Regulations (C.F.R.) Section 122.21(a) — Duty to apply.
Because the information provided is inadequate to determine whether the draft permit meets the
guidelines and requirements of the Clean Water Act (CWA), I request that a complete permit
application for this facility be submitted that meets the requirements of 40 C.F.R. § 122.21(a).
Pursuant to federal regulatory requirements and language of Section VII.A. of the North Carolina
EPA National Pollutant Discharge Elimination System Memorandum of Agreement (MOA), this
letter constitutes an interim objection to the issuance of this permit. In accordance with the
MOA and federal regulations, the full period of time for review of this draft permit will
recommence when the requested information is received by this Office.
Additionally, we have completed our review of the facility's CWA Section 316(a) Report
entitled, Assessment of Balanced and Indigenous Populations in Mountain Island Lake near
Riverbend Steam Station, (dated August 2009) which was received via e-mail on May 13, 2010.
Our comments on this report are outlined below.
Section 316(a) Report and the Study Plan for the Subsequent Permit
The report lacks detail and did not generate information sufficient to support a Section
316(a) variance determination for the next permit cycle. The Environmental Protection
Agency's (EPA) comments are submitted in order to ensure that the study plan to be developed
during the next permit cycle will generate information sufficient to support a determination of
whether the power plant's thermal variance under Section 316(a) of the CWA can be approved.
EPA recognizes that, under 40 C.F.R. § 125.73(c), existing sources seeking variance
renewal are not typically required to conduct the same detailed, comprehensive studies required
under §§ 125.72(a) and (b). Also, under § 125.73, existing sources can base their demonstration
Internet Address (URL) • http.//www.apa gov
Recycled/Recyclable • Pdnled with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)

on a lack of appreciable harm instead of completing predictive studies. However, under §
125.72(c), the type of detailed studies contemplated under §§ 125.72(a) and (b) can be required
whenever determined to be necessary. After examining the record of prior 316(a) variance
determinations for the Riverbend Station, EPA has concerns regarding the need for a more
thorough examination and definition of the Balanced and Indigenous Population (BIP), the
identification of Representative Important Species (RISs), and a closer examination of whether
the variance is protective. Given the thinness of the available record for prior variance
determinations, EPA believes a more focused study is needed. EPA acknowledges that Duke
Energy has in the past collected a substantial amount of data in support of its variance. Duke
Energy may use existing data in completing its study and may incorporate the existence of such
data into the monitoring program plan design; however, the existing data needs to be evaluated
and presented in the context of a BIP definition that the existing record does not adequately
provide.
Section 316(a) of the CWA contains the term "BIP" but does not define it. However, 40
CY R. § 125.71(c) defines the term "balanced, indigenous community"i as:
"A biotic community typically characterized by diversity, the capacity to sustain itself
through cyclic seasonal changes, presence of necessary food chain species and by a lack
of domination by pollution tolerant species. Such a community may include historically
non-native species introduced in connection with a program of wildlife management and
species whose presence or abundance results from substantial, irreversible environmental
modifications. Normally, however, such a community will not include species whose
presence is attributable to the introduction of pollutants that will be eliminated by
compliance by all sources with section 301(b)(2) of the Act: and may not include species
whose presence or abundance is attributable to alternative effluent limitations imposed
pursuant to section 316(a)."
The Environmental Appeals Board stated in its decision in In Re Dominion Energy
Brayton Point, LLC, 12 Environmental Appeals Decision (E.A.D.) 490 (2006)(`Brayton Point"),
"this definition clearly envisions a consideration of more than the population of organisms
currently inhabiting the water body. In this vein, although it permits inclusion of certain
`historically non-native species' that are currently present, it explicitly excludes certain currently
present species whose presence or abundance is attributable to avoidable pollution or previously -
granted section 316(a) variances."
Page 557 of the Brayton Point E.A.D goes on to further state that a BIP "can be the
indigenous population that existed prior to the impacts of pollutants, not solely the current
populations of organisms."
To the question of how a permittee should identify a BIP in an area that has been altered
by impacts from an existing thermal discharge, the Brayton Point E.A.D. points out that it may
be appropriate to use a nearby water body unaffected by the existing thermal discharge as a
reference area. Examination of an appropriate reference area may be applicable in this case.
"Balanced, indigenous community" and BIP are equivalent terms
2

The definition of "balanced, indigenous community" at 40 C.F.R. § 125.71(c) contains
several key elements. To be consistent with the regulations, each of these key elements should
be specifically addressed in the demonstration, and the facility's CWA Section 316a Monitoring
Plan should be designed to generate information relevant to these elements. Those elements
include: (1) "a population typically characterized by diversity at all tropic levels;" (2) "the
capacity to sustain itself through cyclic seasonal changes;" (3) "presence of necessary food chain
species;" (4) "non -domination of pollution -tolerant species;" and (5) "indigenous." Each of
these elements is discussed in more detail below:
1. "A population typically characterized by diversity at all tropic levels" means that all of the
major tropic levels present in the unaffected portion of the water body should be present in the
heat affected portions. EPA recognizes that community structure differences will occur,
however, the number of species represented in each tropic level in the unaffected portions should
be reasonably similar in the heat affected portions of the water body. Sampling and analysis of
fish and invertebrate communities should be done such that the major tropic levels are identified
and represented by reasonably similar species distributions. Also, the study plan should be
expanded to include some observations of wildlife (i.e., water fowl, mammals, amphibians, etc.)
both upstream and immediately downstream of the discharge point that may be impacted by the
thermal discharge.
2. "The capacity to sustain itself through cyclic seasonal changes" means that any additional
thermal stress will not cause significant community instability during times of natural extremes
in environmental conditions. Community data should be collected during normal seasonal
extremes as well as during optimal seasonal conditions. Data should be compared between heat
affected and unaffected portions of the receiving water body to account for normal community
changes corresponding with a change in season.
3. "Presence of necessary food chain species" means that the necessary food webs remain intact
so that communities will be sustaining. We believe that exhaustive food web studies are not
necessary provided that invertebrate, fish and wildlife communities are otherwise healthy, i.e.,
represented by sufficiently high species diversity and abundance (appropriate for that portion of
the receiving water body) for the identified tropic levels and sustaining through normal seasonal
changes.
4. "Non -domination of pollution -tolerant species" means that in the case of a thermal effluent,
community assemblages in heat affected portions of the lake dominated by heat tolerant species
do not constitute a BIP. EPA recognizes that because all species have varying levels of thermal
tolerance, communities in the heat affected portions of the water body may possess altered
assemblages in terms of species present and abundance. All community data should be
collected, analyzed and presented to clearly demonstrate that affected communities have not
shifted to primarily heat tolerant assemblages.
5. "Indigenous" has been further clarified in the regulations: "Such a community may include
historically non-native species introduced in connection with a program of wildlife management

and species whose presence or abundance results from substantial, irreversible environmental
modifications. Normally, however, such a community will not include species whose presence is
attributable to the introduction of pollutants that will be eliminated by compliance by all sources
with section 301(b)(2) of the Act: and may not include species whose presence or abundance is
attributable to alternative effluent limitations imposed pursuant to section 316(a). " EPA
recognizes that non -indigenous species are present in most aquatic systems in the United States.
All community data should be analyzed and presented to demonstrate that community
assemblages in the heat affected portions of the receiving water body are not significantly
different from non -affected communities with regard to the number of non -indigenous species in
the assemblages.
hi addition to the foregoing components of the BIP definition, the study plan should also
include provisions for the identification of RIS (e.g., a list of threatened, endangered, thermally
sensitive, or commercially or recreationally valuable species in up- and down -stream of the study
area), as contemplated in 40 C.F.R. § 125.72(b). 40 C.F.R. § 125.71(b) defines RIS as "species
which are representative, in terms of their biological needs, of a balanced, indigenous community
of shellfish, fish and wildlife in the body of water into which a discharge of heat is made."
The following EPA comments should be specifically addressed in the study plan prior to
Duke Energy commencing sampling during the term of the next NPDES permit. The plan
should:
a) include available information on wildlife in the receiving water body areas based on
communications with North Carolina's Wildlife Management Agency. See
item 1 above.
b) include a diagram depicting the thermal plume under the worst case scenario
and address the presence or absence of a zone of passage for which fish can
travel around the thermal plume.
e) provide information of which fish collected are either heat -sensitive or
nuisance species. See item 4 above.
d) provide a list of any lake species that are endangered or threatened in accordance with
federal and state regulations.
e) analyze and present data to clearly demonstrate that affected communities
have not shifted to primarily heat tolerant assemblages
f) include recent data or information on benthic macroinvertebrates. See item 1 above.
g) analyze and present all data to demonstrate that community assemblages in the heat
affected portions of the receiving water body are not significantly different from non-
affected communities with regard to the number of non -indigenous species in the
assemblages
4

To reiterate, in order to ensure that Duke Energy's future study plan for the receiving
water body is adequate to demonstrate that the power plant should get continuance of a Section
316(a) variance during the term of its next NPDES permit, EPA requests the opportunityto
review a draft 316(a) plan prior to Duke Energy commencing the study.
Lastly, the Riverbend plant has an ash pond. Due to the ash spill that occurred at the
TVA Kingston, EPA's Office of Water recommends NPDES permits for power plants with coal
combustion waste impoundments (i.e., ash ponds) include language regarding structural integrity
inspections. This language agrees with the requirements of 40 C.F.R. § 122.41(e), which
addresses proper operation and maintenance of wastewater treatment facilities. See the enclosed
model language addressing coal combustion waste impoundments, which should be incorporated
into the draft permit.
If you have any questions, please call me or have your staff contact Ms. Karrie-Jo Shell at
[phone].
Sincerely, -
4
Giattina
W&ex.-Protection Division
Enclosure
cc: Mr. Allen Stowe
Duke Energy

Model Permit Language
A. Impoundment Design, Construction, Operation, and Maintenance
(1) All impoundments used to hold or treat wastewater and other associated wastes shall be
designed, constructed, operated, and maintained to prevent the discharge of pollutants to
waters of the United States, except as authorized under this permit.
(2) Design, construction, operation, and maintenance of any impoundment shall be in
accordance with all relevant State and Federal regulations and shall be certified by a
qualified, State -registered professional engineer and permitted and inspected by the
appropriate agency prior to use. When practicable, piezometers or other instrumentation
shall be installed as a means to aid monitoring of impoundment integrity.
B. Impoundment Integrity Inspections
(1) All impoundments shall be inspected at least monthly by qualified personnel with
knowledge and training in impoundment integrity. The term qualified personnel means
personnel having successfully completed the Mine Safety and Health Administration
Qualification for Impoundment Inspection course in addition to the Annual Retraining for
Impoundment Qualification, or equivalent courses. In addition, impoundments shall be
inspected annually by a qualified, State -registered professional engineer. Additional
inspections by qualified personnel shall be done within 7 days after large or extended rain
events (i.e., 10 -year, 24 hour precipitation event).
(2) Inspections shall, at a minimum, include observations of dams, dikes and toe areas for
erosion, cracks or bulges, seepage, wet or soft soil, changes in geometry, the depth and
elevation of the impounded water, sediment or slurry, freeboard, changes in vegetation
such as overly lush, dead or unnaturally tilted vegetation, and any other changes which may
indicate a potential compromise to impoundment integrity. The findings of each inspection
shall be documented in a written inspection report.
(3) Remediation Measures. Within 24 hours of discovering changes that indicate a potential
compromise to the structural integrity of the impoundment, the permittee shall begin
procedures to remediate the problem. Changes such as significant increases in seepage or
seepage carrying sediment may be signs of imminent impoundment failure and should be
addressed immediately.
Other issues which may have long term impacts on integrity, such as trees growing on the
impoundment or vegetation blocking spillways, shall be cleared within thirty days of first
observation.
C. Reporting and Recordkeeping Requirements for Impoundments
(1) Within 5 days of discovering any changes in the impoundment that indicate a potential
compromise to the structural integrity, the permittee must notify the NPDES Permitting

Authority in writing describing the findings of the inspection, corrective measures taken,
and expected outcomes. Failure to do so will be a violation of this permit.
(2) The permittee shall submit an annual report to the NPDES Permitting Authority
summarizing findings of all monitoring activities, inspections, and remediation measures
pertaining to the structural integrity, design, construction, and operation and maintenance
of all impoundments.
(3) The permittee shall maintain records of all impoundment inspection and maintenance
activities, including corrective actions made in response to inspections and all other
activities undertaken to repair or maintain the impoundment. All records shall be kept on
site and made available to State or Federal inspectors upon request.
(4) All pertinent impoundment permits, design, construction, operation, and maintenance
information, including but not limited to- plans, geotechnical and structural integrity
studies, copies of permits, associated certifications by qualified, State -registered
professional engineer, and regulatory approvals, shall be kept on site and made available to
State or Federal inspectors upon request.
D. Permit Re -opener Requirement
The Director may re -open this permit to incorporate more stringent requirements or any
applicable standards pertaining to the operation and maintenance of coal combustion waste
impoundments.

Chernikov, Sergei
From: Stowe, Allen [Allen [e-mail]]
Sent: Tuesday, May 18, 2010 9 59 AM
To: Chernikov, Sergei
Cc: Jones, Steve
Subject: Riverbend Steam Station - Draft NPDES Permit
Sergei,
Duke Energy Carolinas, LLC has reviewed the draft NPDES permit for Riverbend Steam Station and offer the following
comments -
1 Note that we plan to transition our facilities to the NC DENR eDMR system in the future Therefore, some
revision of or interpretative guidance associated with boder plate language in the permit requiring written
signatures may be in order
2 Change "Duke Energy Corporation" to read "Duke Energy Carolinas, LLC' throughout the permit.
Please let me know if any additional information is required on our part Thanks
Allen Stowe
EHS Water Management
Duke Energy Carolinas
Allen.Stowe(@duke-eneriay.com
704-382-4309 (Office)
704-516-5548 (Cell)

06/0,7/2010 13:25 7046633772
MEMORANDUM
MRO PWSS
April 28, 7010
To Butt Setzer, Regional Engineer
NC DENR / DEH /Public Water Supply Scction
Nlooresville Regional Office
PAGE 01/01
FILM
r
From Seigci Chernikov, Envu onmcntal E- ngincer 1I, Complcx NPDI✓S Unit,
Division of Water Qualtry (fax -919-807-6495)
Subject Review of the discharge locauons fo+ the following
Review of Draft NFDES Pexmit NC0004961
Riiverbend Steam Station
Gaston County
Please indicate below by June 1, 2010 your agency's position or view -point on the facibty
Listed above We cannot issue tlic permit without your concurrence Please icturn chis foam
ac your earliest conN-eruencc
RESPONSE
his agency has reviewed the draft permit and detetmined that tlhc proposed
discharge will not be sufficiently close to any exi,qtuig or known proposed
t on
public water supply lrttauty
zn a of this1eermlt provided ethecfacllity tseopexlte
We concur with the iss , P
and maintained properly, the
contrati enc tl�ci designated water prior hty standards rgc
and the discharge docs not
itions
Concurs with issuance of t1 -ie above peirrut, provided the following cond
are met
Opposes the issuance of the above perrrnt, baecd on reasons stated below, of
atrachcd
SDate e;rw"r
igned ' -.
cc file JUN — 7 ZM

06/07/2010 13:25 7046633772 MRO PWSS
c
f 3
April 28, 2010
MEMORANDUM
To Btitt Setzer, Regional Engineer
NC DENR / DEH /Public Water Supply Sectson
Mooresville Regional Office
From. Seigci Chcrn,kov, Enviionmcrimi Engineer JI, Complex NPDES Unit,
Division of Water Quallry (fax -919-807-6495)
Subject Review of the discharge locarions fo+ the following
Review of Draft NFDE,S Permit NC0004961
Riveirbend Steam Station
Gaston County
Please indicate below by June 1, 2010 your agency's position or view -point on the facility
listed above We cannot Issue the permit wirhout your concurrence Please return this form
at your earliest com-cruence.
RESPONSE -
L/ This agency has reviewed the djaft permit and determined that the proposed
discharge will not be sufficiently close to any existing or known proposed
public water supply Intake so as to c+cate an adverse effect on water quality
We concur with the issuance of this permit provided the facility is operated
and maintained properly, the stated effluent hints arc met poor to discharge,
and the discharge docs not contravene the designated water quahty standards
Concuis with Issuance of the above peirnir, Provided the followmg conditions
sue met
S
C
Opposes the issuance of the above permit l�ascd on reasons stated below, or
attached
PAGE 01/01
N

The Charlotte Observer Publishing Co.
Charlotte, NC
North Carolina ss Affidavit of Publication
Mecklenburg County)
THE CHARLOTTE OBSERVER
--------------------------------------------------+------------------------
I
DINA SPRINKLE
NCDENR/DWQ/POINT SOURCE BRANCH
1617 MAIL SERVICE CENTER
RALEIGH NC 27699
I
REFERENCE: 30063432
6503249 Public Notice
Before the undersigned, a Notary Public of said
County and State, duly authorized to administerI
PUBLIC NOTICE
�,UBJECT 'The
North Carolina Environmental Management
oaths affirmations, etc., personally appeared, I
Commission proposes to issue the following NPDES wastewater
is Inviting comment on the draft
being duly sworn or affirmed according t0 Law,
Discharge permits, and public
cermits Additionally, a public hearing has been scheduled to
doth depose and say that he/she is a I
brovide additional opportunity for comments
puke Energy Corp Rwerbend Steam Station (Gaston County),
representative of The Charlotte Observer I
NPDES Permit #NC0004961
Duke Energy Corp Allen Steam Station (Gaston County), NPDES
Publishing Company, a corporation organized and I
Permit #N000049pp79
NPDES PerDuke m #NC000498711 Steam Station (Catawba County),
doing business under the laws of the State of I
appcaaton ofOArticle 2lhe bof Chapter 1asis of 413 General Statff utes of Norteview h
Delaware, dpublishing kThe
r ana newspaper p per nown as I
Carolina, and other lawful standards and regulations, the North
Carohna Environmental Management Commission proposes to
fprthese subjecto
Charlotte Observer in the city of Charlotte , I
reissue NPDES ns andmits
dittoes and nue the
pollutant limitations and special conditions and to continue the
County of Mecklenburg, and State of North Carolina)
316(a) temperature variances The Director of the Division of
Water Quality pursuant to NCGS 143-2151(c)(3) and Regulation
15 NCAC 2H, Section 0100 has determined that it is i0 the public
and that as such he/she is familiar with the I
I interest that a hearing be held to receive all pertinent public
comment on whether to issue, modify, or deny the permits
books, records, files, and business of said I
PROCEDURE Written comments on the draft permits will be
accepted until the date of the Public Hearing Any person or
Corporation and by reference to the files of said I
organization desiring to make oral comments should register to
do So at the hearing The time available for oral comments may be
publication, the attached advertisement was I
limited by the Hearing Officer Oral presentations that exceed
by three written copies
inserted. The following is correctly copied from I
three minutes should be accompanied
The hearing record may be closed at the conclusion of
)the hearing
the books and files of the aforesaid Corporation I
WHEN Tuesday-October19,2010at700pin
begins 6 00 m)
and Publication.
FI' (Registration at p
f WHERE Charles Mack Citizen Center
215 North Main Street
Mooresville, North Carolina 28115
INFORMATION A copy of the draft NPDES permits can be
,downloaded from the following link
htto /loorl-I ncdenPorghv b/wol los/nodes/calendar
,The draft permits are also available by writing or calling
Ms Dma Sprinkle
NC Division of Water Quality/
-
NPDES Unit
1617 Mail Service Center
l
' Raleigh North Carolina 27699.1617
•�
Telephone number [phone]
PUBLISHED ON 09 17 I
/
The application and other mlormation are on file at the Division of
I Water Quality, 512 North -Salisbury Street, Room '925 of the
i Archdale Building in Raleigh, North Carolina and at the Division's
Mooresville Regional Office (610 East Center Avenue Suite 301
be duringg normal
Mooresville, NC 28115) They may inspected
V hle are availal]to upon
office hours Copies of the information on
-request and payment of the costs of reproduction All such
comments and requests regarding this matter should make
reference to the permit numbers NC0004961, NCDOD4979, and
i NC0004987
LP6503249
1
AD SPACE: 130 LINE
FILED ON: 09/23/10
-------/ d - -nX
-+
NAME: / TITLE:
DATE: _ V2 3 �nln
In Testimony Whereof I have hereunto set my hand and affixed my seal, the
day Jandear aforesaid�05���Y�omnission
NotaExpires:
My Commission Expires May 27, 2011

DENR/DWQ
. ' FACT SHEET FOR NPDES PERMIT DEVELOPMENT
NPDES No NC0004961
Facility Information
Applicant/Facility Name.
Duke Energy Corporation — Riverbend Steam Station
Applicant Address:
13339 Hagers Ferry Road, Huntersville, North Carolina 28078
Facility Address.
P O Box 367, Mount Holly, North Carolina 28120
Permitted Flow
No limit
Type of Waste-
100% industrial
Prim SIC Code 4911 — Electric Services
Facility/Permit Status:
Class I/Achve, Renewal
County
I Gaston County
Miscellaneous
Receiving Stream
Catawba River
(Mt. Island Lake)
Regional Office-
Mooresville
Stream Classification-
WS -IV and B
State Grid / USGS Quad:
F15Sw
303(d) Listed?
No
Permit Writer.
Sergei Chernikov
Subbasm:
03-08-33
Date
I April 2, 2010
Drainage Area (miz)
1800
001 Lat 35'21'28"N Long 80° 58' 12" W
002 Lat 350 22' 06" N Long 80'57'31"W
002B Lat 35021'51"N Long 80'58' 11" W
Summer 7Q10 (cfs)
80
Winter 7Q10 (cfs)
30Q2 (cfs)
Average Flow (cfs):
2700
IWC (%):
10%
' effoUil WKo
Duke Energy's Riverbend Steam Station is a coal fired steam electric plant in Gaston County.
The facility has three permitted outfalls in the current NPDES discharge permit. The sources of
wastewater for these outfalls include non -contact cooling water, ash basin discharge, sanitary
waste, stormwater from process areas, and sump overflows. The facility has no FGD scrubber.
In addition to NPDES Permit NC0004961, the facility also holds 0388R20 (air permit) and
NCD024717423 (Hazardous wastes). The facility is typical of most fossil power plants and is
subject to 40 CFR 423 — Steam Electric Power Generation. Guidelines require that the NPDES
permit limit Fe, Cu and oil and grease.
The following descriptions of the wastes at each outfall are offered:
001 — once -through condenser cooling water and intake screen backwash
002 — ash basin discharge; includes wastewater from the yard drain sump, groundwater
remediation, turbine room sumps, stormwater runoff, cooling water, reverse osmosis unit,
misc. seal and lab test waters, boiler blowdown, track hopper sump, boiler room sump,
turbine non-destructive testing and other misc. process wastewaters
002A- yard drain sump overflow
This facility discharges to the Catawba Riverjust above Lake Wylie in sub -basin 03-08-33. The
receiving stream is not listed as impaired, though dischargers upstream of Lake Wylie are subject
to the nutrient management strategy developed for that watershed.
Fact Sheet
NPDES N00004961 Rene",a(
Page I

[b 1
REASONABLE POTENTIAL ANALYSIS (RPA)
The Division conducted EPA -recommended analyses to determine the reasonable potential for
toxicants to be discharged by this facility from outfall 002. Calculations included- arsemc,
selenium, copper, and iron (please see attached). The renewal application listed 4.9 MGD as a
current flow. However, this flow can fluctuate. Therefore, the flow of 5.74 MGD was used in
calculations to assure protection of the wate- quality in the receiving stream. This flow was used
previously in RPA.
TEMPERATURE VARIANCE ,
The facility has a temperature variance In order to maintain the variance the facility has to
conduct annual biological and chemical monitoring of the receiving stream to demonstrate that it
has a balanced and indigenous macroinvertebrate and fish community. The latest BIP (balanced
and indigenous population) report was submitted to DWQ in August of 2009. The ESS has
reviewed the report and concluded that Mountain Island Lake near Riverbend Station has a
balanced and indigenous macroinvertebrate and fish community.
Requested Modifications/Additions
With the permit application for renewal, Duke Power has requested the following modifications:
Monitoring Frequencies
Parameter
Present
Proposed
Oil & Grease
2/year
1/year
TSS
2/month
1/month
Total Nitrogen
2/year
1/year
Total Phosphorus
2/year
1/year
Total Copper
Quarterly
none
Total Iron
Quarterly
I none
Request by the permittee to reduce monitoring from 2/month to monthly for TSS and to reduce
monitoring for Oil and Grease from 2/year to annually was granted. Request to eliminate
monitoring for Cu and Fe was declined because the Division needs the metals data to conduct
RPA. Request to reduce monitoring for Nitrogen and Phosphorus was also declined because the
Division needs sufficient data to evaluate impact of the discharge on the receiving stream.
Toxicity Testing:
Current Requirement: 24hr Chronic P/F @ 10%
Recommended Requirement: 24hr Chronic P/F @ 10%
Monitoring Schedule: January, April, July, October
This facility has passed all chrome toxicity tests during the previous permit cycle.
Compliance Summary:
This facility has been compliant with all parameters during the period from 01/01/2006 through
12/31/2009. The latest compliance evaluation inspection conducted on 02/19/2008 concluded
that the facility is in compliance.
Proposed Changes:
Limits No changes are proposed.
Fact Sheet
NPUES NC0004961 Renewal
Page 2

Y, • ' Monitoring Frequencies: Request by the permittee to reduce monitoring from 2/month to
monthly for TSS and to reduce monitoring for Oil and Grease from 2/year to annually was
• granted. Groundwater monitoring was added to the permit.
Proposed Schedule for Permit Issuance:
Draft Permit to Public Notice- April 28, 2010 (est.)
Permit Scheduled to Issue. June 21, 2010 (est.)
STATE CONTACT -
If you have any questions on any of the above information or on the attached permit, please
contact Sergei Chermkov at [phone].
CHANGES TO THE FINAL PERMIT:
• The Special Condition entitled "Structural Integrity Inspections of Ash Pond
Dams" was added to the permit, please see Special Condition A (12.).
• The Special Condition entitled "CWA Section 316(A) Thermal Variance" was
added to the permit, please see Special Condition A.(13.).
• The Special Condition entitled "Fish Tissue Monitoring near Ash Pond
Discharge" was added to the permit, please see Special Condition A.(14.).
• The Special Condition entitled "Instream Monitoring" was added to the permit,
please see Special Condition A.(15.).
• The Special Condition entitled "Ash Pond Closure" was added to the permit,
please see Special Condition A.(16.).
• Quarterly effluent monitoring for mercury was added to Outfall 002
Fact Sheet
NPDES N00004961 Renewal
Page 3

B
REASONABLE POTENTIAL ANALYSIS
Duke River Bend Steam Stati®n-
NC0004961
Time Penod 2005-2010
Qw (MGD)
574
7Q10S (cfs)
80
7Q10W (cfs)
0
3002 (cfs)
0
Avg Stream Flow, QA (cfs)
2700
Rec'wng Stream Catawba River
WWTP Class
IWC (%) @ 7Q10S 10 008
@ 7Q10W N/A
@ 30Q2 N/A
@ QA 0.3284
Stream Class WS -IV B -CA
Outfall 001
Qw=5.74 MGD
'Legend
C = Carcinogenic
NC = Non -carcinogenic
A = Aesthetic
Freshwater Discharge
4961 -RPA -2010 xls, rpa
4/20/2010
STANDARDS &
PARAMETER
TYPE
CRITERIA (2)
PQL
Units
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
NCWQS/ %FAV/
n #Det MaxPredCw AllowahleCw
(t)
Chronic Acute
Acute N/A
no limit
Arsenic
C
10
ug/L
22 22
3531
...........................................
Chronic 3,045
Acute N/A
no limit
Iron
C
10000
ug/L
24 24
5974
_ _
Chronic 304,473
Acute N/A
no limit
Arsenic
NC
50 15
ug/L
22 22
3531
----------------------------
Chronic 500
Acute 7
no limit, Action level standard
Copper
NC
7 AL 73
ug/L
24 12
1149
_ --- _
----------------------------
Chronic 70
Acute 56no
limit
Selenium
NC
50 56
ug/L
22 16
79
_ _ _ -----------------------------
-
Chronic 50
'Legend
C = Carcinogenic
NC = Non -carcinogenic
A = Aesthetic
Freshwater Discharge
4961 -RPA -2010 xls, rpa
4/20/2010

REASONABLE POTENTIAL ANALYSIS
4961 -RPA -2010 xls, data
- 1 - 4/7/2010
-
Arsenic
-
Iron
Date
Data
BDL=1/2DL
Results
Date
Data
BDL=1/2DL
Results
1
form 2C
690
690
Std Dev
379081
1�f
130
1300
Std Dev
688992
2
�,
198
198
Mean
485000
2
30
300
Mean
1241667
3
"F
497
497
C V
07816
3
100
1000
C V
05549
4
j
626
626
n
22
4
60
600
n
24
5
31 9
31 9
5
90
900
6
450
450
Mult Factor =
27100
6
Gr
60
600
Mult Factor =
20600
7
i y
272
272
Max Value
1303 ug/L
7'
70
700
Max Value
290 0 ug/L
8
r
327
327
Max Pred Cw
3531 ug/L
8
120
1200
Max Pred Cw
597 4 ug/L
9
198
198
9
120
1200
10 -
66
66
10
70
700
11
@
53
53
11
250
2500
12
123
123
12
170
1700
13
127
127
13
r,
200
2000
14,
k
309
309
14.,
°
130
1300
15
Oct -2006
787
787
15
;
60,
600
16
Jul -2006
.
1160
1160
16, ,
90
goo
17
Apr -2006
106'2
1062
17
'w
270
2700
18
41 6—
416
18
170
1700
19
Oct -2005
1303
1303
19F*
, 110
1100
20
Jul -2005•
r `
1120
1120
20
290
2900
21
257
257
21
900
900
22 `
310,
310
22`
80
800
23
23 `
�
130
1300
24
24
�
90
900
25
YZ
25'
26
26
27
27{+
8
28,
2
29
30
*
30
31
31
32
32,
Ct
33
_ ,
33
34
34
35,
35 ;
36
36
37"
37
38"
38
39
39
40
40,
41
41
42
42,
43
43
44
44
45
45
46
46
47
47
48
48
tK
49
49
50
50
51
51
,
52
1
52�
53
53C
54
54
55
55
is
56,
56
57
57
58
58
.
59
59
60
60
199
199
200�
200
r
4961 -RPA -2010 xls, data
- 1 - 4/7/2010

REASONABLE POTENTIAL ANALYSIS
4961 -RPA -2010 As, data
-2- 4/7/2010
Arsenic
Copper
Date
Data
BDL=1/2DL
Results
Date
Data
BDL=1/2DL
Results
1
C-71
A= c
69 0
69 0
Std Dev
37 9081
1
5
50
Std Dev
72049
2w'5
19 8
198
Mean
485000
2
�'<
5
25
Mean
67083
3
y �!
497
497
C V
07816
3
v<
5
25
C V
1 0740
4
626
626
n
22
4
1<;
5
25
n
24
5
31 9
31 9
5
5
25
6
s"
450
450
Mult Factor =
27100
6
<„
5
25
Mult Factor=
33800
7
1�.
272
272
Max Value
130.3 ug/L
7
�2
5
25
Max Value
34 0 ug/L
8
327
327
Max Fred Cw
353 1 ug/L
83
5
50
Max Fred Cw
114 9 ug/L
9
=
198
1980
9<
5
25
10
66
660
10
34
340
11
53
530
11
19
190
12
123
1230
12
9
90
13
127
1270
13
$<
5
25
1414
3090
14
'<
5
25
15
�'
787
7870
15
5
50
16
1160
11600
16
'
11
11 0
17
18
1062
416
10620
4160
17
18
6
60
6
60
19
;4
1303
13030
19
5
25
20
{
1120
11200
20
<
5
25
21
257
2570
21
5
25
22
�"
310
3100
22
13
130
23
t
23
10
100
24
Y
24
8
80
25
w
25
26
26
N
27
27
28
Vx{,
28
2929
y
30
30
3131
�'
`
32
32
33
33
34
�n
34
35
35
36
..
36
37
37.
38
38r
39
i4
39
a'
40
eP
40
41
41
42
42
43
43
44
44
45�
4
46
I
t
46
47
c;
47
48
48
49
49
50
50^
51
51
52
52
53
53
54
54
5
3
55
57
57
58
58�
59
59IS
60
199
E
16099
200
200
4961 -RPA -2010 As, data
-2- 4/7/2010

■
REASONABLE POTENTIAL ANALYSIS
4961 -RPA -2010 As, data
-3- 4f71201 0
Selenium
Date
Data
BDL=1/2DL
Results
I form 2C
35
35
Std Dev
„&2
2
12
12
Mean
23864
3
,a
,a
C V
04627
4
26
26
n
22
5
24
24
6
3
30
Mult Factor
18900
7
32
32
Max Value
4 2 ug/L
8
35
35
Max Pred Cw
79u L
9
2
10
10
Q'2
10
11
2
10
12,
3
27
1 3
T
25,
25
14
2
1 0
1 5
29
29
16
4
42
17
3
33
18
2-
10
19
4
35
20
4
41
21;
IN
2
21
22,
2
10
23
24
25'
26
27
28,
29-
30,
31
32
33
34
35
36
37;
38:
39
40
41
42
43
44
45
46
47
48
49
50
Jf
51
52
53
54
55
56 -
`\]
57
58
59
60
199
00
4961 -RPA -2010 As, data
-3- 4f71201 0

REASONABLE POTENTIAL ANALYSIS
Duke Riven- Bend Steam Station
NC0004961
Time Period 2005-2010
Qw (MGD)
574
7Q10S (c/s)
80
7Q10W (cts)
0
30Q2 (c(s)
0
Avg Stream Flow, QA (cts)
2700
Rec'ving Stream Catawba River
WWTP Class
IWC (%) @ 7Q 10S 10 008
@ 7Q10W NIA
@ 30Q2 N/A
@ QA 0.3284
Stream Class WS -IV B -CA
Outfall 001
Qw=5.74 MGD
'Legend
C = Carcinogenic
NC = Non -carcinogenic
A = Aesthetic
Freshwater Discharge
4961 -RPA -2010 xis, rpa
4/2012010
STANDARDS&
PARAMETER
TYPE
CRITERIA (2)
PQL
Units
REASONABLE POTENTIAL RESULTS
RECOMMENDED ACTION
NCWQSI %FAV/
n #Det. Max PredCw AllowableCw
(1)
Chronic Acute
Acute N/A
no limit
Arsenic
C
10
ug/L
22 22
3531
............
___-_-_-_-___-_-_________-_
Chronic 3,045
Acute N/A
no limit
Iron
C
10000
ug/L
24 24
5974
...........................................
Chronic 304,473
Acute NIA
no limit
Arsenic
NC
50 15
ug/L
22 22
3531
_ _ _ _ _
_-_-_-_-___________-_______
Chronic 500
Acute 7
no limit, Action level standard
Copper
NC
7 AL 73
ug/L
24 12
1149
-_-_ _-
_-___-_-_-_-_-_-_ ________-
Chronic 70
Acute 56no
limit
Selenium
NC
50 56
ug/L
22 16
79
_ _ _-_ _
Chronic 50
'Legend
C = Carcinogenic
NC = Non -carcinogenic
A = Aesthetic
Freshwater Discharge
4961 -RPA -2010 xis, rpa
4/2012010

REASONABLE POTENTIAL ANALYSIS
-1-
4961-RPA-2010 xls, data
4/7/2010
Arsenic
Iron
Date
Data
BDL=1/2DL
Results
Date
Data
BDL=1/2DL
Results
1
form_ 2C
690
690
Std Dev
379081
1
130
1300
Std Dev
688992
2
198
198
Mean
485000
2
30
300
Mean
124 1667
3
497
497
C V
07816
3
;
100
1000
C V
05549
4
626
626
n
22
4
60
600
n
24
5
31 9
31 9
5
90
900
6
450
450
Mult Factor =
27100
6
60
600
Mult Factor=
20600
7
r
27,2
272
Max Value
1303 ug/L
7
70
700
Max Value
290 0 ug/L
8
327
327
Max Fred Cw
353.1 ug/L
8
120
1200
Max Pred Cw
597 4 ug/L
9
198
198
9
120
1200
10
66
66
10
70
700
11
53
53
11
250
2500
12
!
123
123
12
170
1700
13
i
127
127
13
200
2000
14
309
309
14
130
130,0
15
Oct -2006
787
7871
5
f
60
600
16
Jul -2006
1160
1160
16
90
900
17
Apr -2006
I
1062
1062
17
p
270
2700
18
41 6
41 6
18
170
1700
19
Oct -2005
1303
1303
19
110
1100
20
Jul -2005
(
1120
1120
20
290
2900
21
kf,'
257
257
21,
900
900
22
31 0
310
22
80
800
23?
.
23
130
1300
24
24
5
90
900
25
25
t
26
26
27
27t
28
28.'
29
29
y"
30
30
31
31
32
32
33
33
34
34
35
;
35
36
36
37
v
37
38
38
39
x;,
39
40
40
41
41
42
42
43
43
44
44
45
45
46
46
47
r
47
48
48
49
P
49
50
50'
51
51
52
52
5353
k
54
54
55
55
56
r
56
57
¢
57
58
t
58
59
59
60
!
60
199
199
200
200
"
-1-
4961-RPA-2010 xls, data
4/7/2010

1
REASONABLE POTENTIAL ANALYSIS
-3-
4961-RPA-2010 xis, data
4/7/2010
Selenium
Date
Data
BDL=1/2DL
Results
1
form 2C
35
35
Std Dev
1 1042
2
1 2
1,2
Mean
23864
3
1 8
1 8
C V
04627
4
26
26
n
22
5
24
24
6
n
3
30
Mult Factor =
1 8900
7
¢,
32
32
Max Value
4 2 ug/L
8
C
35
35
Max Pred Cw
7 9 ug/L
9
<
2
1 0
10
<
2
1 0
11
2
1 0
12
3
27
13
25
25
14
<
2
1 0
15
29
29
16
4
42
17
3
33
18
<
2
1 0
19
4
35
20
4
41
21
2
21
22
<
2
1 0
23
24
n•
25
26
27Y
28
29
30
31
32
�.
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
r
52
53
54
1
55
56
57
58
&t
59
i
60
199
4
200
b
-3-
4961-RPA-2010 xis, data
4/7/2010

Recommended Surface Water Monitoring Within Compliance Boundary of Coal Ash Ponds
w� 1
po FGD
11/12/2009
Recommended Surface Water Monitoring
Parameter Description Frequency
Antimony* January, May, September
Arsenic January, May, September
Barium January, May, September
Beryllium January, May, September
Boron** January, May, September
Cadmium January, May, September
Chloride January, May, September
Chromium January, May, September
Copper January, May, September
Iron January, May, September
Lead January, May, September
Manganese January, May, September
Mercury January, May, September
Nickel January, May, September
Nitrate January, May, September
pH January, May, September
Selenium January, May, September
Silver January, May, September
Sulfate January, May, September
Total Dissolved Solids January, May, September
Thallium* January, May, September
Zinc January, May, September
* Priority pollutant monitored in groundwater Specific federal and effluent limitations in NPDES p
apply to priority pollutants.
** Frequently detected parameter in groundwater at ash pond sites.
w� 1
po FGD
11/12/2009

rmits may
Recommended Surface Water Monitoring Within Compliance Boundary of Coal Ash Ponds
11/12/2009