NC0027332_Draft Permit_20240430

•
ROY COOPER
Governor
i 1,
ELIZABETH BISER j t 1
Secretary !
RICHARD E. ROGERS, JR orgr,,,I
Director NORTH CAROLINA
Environmental Quality
April 30, 2024
Alan A. Clare, Senior VP, Power Operations
Tennessee Valley Authority(TVA)
1101 Market Street LP, 2K-C,
Chattanooga, Tennessee 37402
Subject: Your Review of Renewal DRAFT
NPDES Permit NC0027332
TVA Chatuge Hydro Plant
WPCS Class Physical/Chemical PCNC
Clay County
Mr. Clare:
The NC Division of Water Resources (DWR or the Division) received your application to renew the
subject NPDES permit on March 1, 2023, and we regret the delay in processing. Having reviewed
Tennessee Valley Authority's (TVAs) application,we hereby transmit this draft permit for your
review and comment.
Please review this draft carefully to ensure your understanding of its limits and monitoring conditions,
and to correct errors, if any. Concurrent with this notification, the Division will solicit public comment
on this draft by publishing a notice in newspapers having circulation in the general Graham County
area, as required by the NPDES Program. Please provide your written comments, if any, to me, Joe R.
Corporon, P.G. [[e-mail]] no later than May 31,2024 (approximately 30 days after
receiving this document). Your written comments are welcome,but they are not mandatory.
BIMS lists no compliance issues or permit violations for the past five(5)years(Jan2020-Apr2024).
DWR acknowledges TVA's continuing request to apply best management practices (BMPs) to
Outfall 002 in lieu of regular monitoring because of the consistently infrequent discharges.
Monitoring remains waivered-no changes recommended.
The Division understands that TVA has made no significant alterations to the treatment systems or
processes. We therefore have made only minimal permit updates for renewal.
RENEWAL SUMMARY:
• The Division has replaced footnotes regarding pH monitoring by including the details
within the effluent tables [see sections A. (1.) and A. (2.)].
• renewal has substituted the Oil & Grease test method,previously 00556 [soaps and
fats], changed to 00552 [hexane extraction method to better detect petroleum products.
• Monitoring remains unchanged for these outfalls. DWR has updated renewal text only.
North Carolina Department of Environmental Quality I Division of Water Resources
512 North Salisbury Street 11617 Mail Service Center I Raleigh,North Carolina 27699-1617--919.707.9000

Alan A. Clare, Senior VP,TVA
Renewal of Permit NC0027332
Draft Permit Review
Pg,2
Monitoring parameters for the above remain unchanged except renewal has substituted the test
method for Oil & Grease [previously 00556 for soaps and fats], now updated to EPA hexane
extraction method 00552 [to better detect petroleum products]. Otherwise, DWR has only updated
permit text for renewal.
The NPDES standard conditions (Parts II, III, and IV), are part of this permit but are not included in
this draft document(cover, map, and Part I). The latest version of Parts II, III, and IV are available
at https://bit.ly/3k5NFaL can be viewed online or downloaded as a PDF file.
Following the mandatory 45-day public comment period, the Division will review all pertinent
comments, if any, and take appropriate action prior to issuing an NPDES permit final. If you have
questions concerning this draft, please e-mail me at [[e-mail]].
Respectfully,
Joe R. Co r oron, .G.
Compliance and Expedited Permitting Unit
Enclosure: NPDES Permit NC0027332 (Renewal DRAFT)
ec: NPDES Program Files/Laserfiche
ARO,Andrew Moore[andrew.w.moore@a,deq.nc.gov]
ARO,Lauren E.Armeni[[e-mail]]
DWR/OCU,Jeffery Talbott[[e-mail]]

NPDES Permit NC0027332
STATE OF NORTH CAROLINA
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF WATER RESOURCES
PERMIT
TO DISCHARGE WASTEWATER UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
(NPDES)
In compliance with the provisions 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, the
Tennessee Valley Authority (TVA)
is herebyauthorized to discharge wastewater from a facilitylocated at
g
Chatuge Hydro Plant
Y
Chatuge Dam Road, Hayesville 28904
Clay County
to receiving waters designated as the Hiwassee River in the Hiwassee 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 2024.
This permit and authorization to discharge shall expire at midnight on August 31, 2028.
Signed this day 2024.
John E. Hennessy, Section Chief
Water Quality Regional Operations
Division of Water Resources
By Authority of the Environmental Management Commission
Page 1 of 7

NPDES Permit NC0027332
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.
Tennessee Valley Authority
is hereby authorized to:
1. continue to discharge waters from sumps, drains, and other miscellaneous wastewaters
associated with hydroelectric facilities consisting of, but not limited to:
• a station sump, which receives flow from wheel pit leakage,penstock
envelope leakage, and powerhouse floor drains (Outfall 001)
• sump water from draft tube unwatering operations (Outfall 002)
continue to discharge once-through cooling waters and similar wastewaters
associated with hydroelectric facilities consisting of:
• generator air-cooling water(Outfall 003A)
• generator thrust bearing cooling water(Outfall 003B)
these facilities located at Chatuge Hydro Plant, Chatuge Dam Road, Hayesville, Clay County; and
2. discharge from said treatment works via Outfalls 001, 002, 003A & 003B, at a location specified
on the attached map, into the Hiwassee River [Stream Segment 1-(15)], a waterbody currently
Classified C within hydrological unit 04-05-01 [HUC 060200020203] of the Hiwassee River
Basin.
Page 2 of 7

NPDES Permit NC0027332
PART I
A. (1.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B .0400 et seq.,02B .0500 et seq.] [15A NCAC 08G .0302 -WPCS Class PCNC]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee is
authorized to discharge once-through cooling waters (generator cooling water, generator thrust bearing
cooling water) and similar wastewaters associated with hydroelectric facilities from Outfalls 001 & 002.
Such discharges shall be limited, monitored, and reported 1 by the Permittee as specified below:
EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS
[parameter codes] Monthly Daily Measurement Sample Sample
Average Maximum Frequency Type Location 2
Flow(MGD) 50050 Monitor&Report Quarterly Estimate E
Free Oil Visual Sheen (yes=1 no=0)3'4'5 51689 Monitor&Report Quarterly Estimate E
pH(Standard Units)4'5 00400 Not <6.0 or>9.0 s.u. Footnotes 4,5 Grab E
Oil& Grease(O&G)(mg/L) 4'5 00552 15 mg/L 20 mg/L Footnotes 4,5 Grab E
[EPA hexane extraction method
Footnotes:
1. Electronic Reporting of Discharge Monitoring Reports(eDMRs):
a. The Permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application
system. See Condition A. (4.).
b. Monitoring results for a given Calendar Quarter shall be reported in eDMR no later than the 30th day of the
month following the monitoring of said quarter.The first eDMR is due one month after the first calendar quarter,
i.e.,four(4)months after the permit Effective date. [Quarterly reporting for this permit is an exception to NPDES
Standard Conditions found in Part I,A. (6.)and Part II,D. (2.).wherein monthly reporting is prescribed.]
2. Sample locations: E—Effluent
3. Free Oil-Visual Sheen:
a. The tailrace for this hydroelectric facility shall be visually inspected for oil sheens at least once per calendar quarter.
b. Cleaning of the Chemical wheel pit is permitted Monthly.When cleaning this pit,the Permittee shall visually
inspect the tailrace for foam and oil.The Permittee shall use pre-approved cleaning solvents only. Should the
Permittee wish to change solvents,a written request shall be submitted to the Division no later than 90 days
prior to use,to include the MSDS for the proposed solvent. See Use of Biocides—Special Condition A. (3.).
c. Free Oil Visual Sheen shall be reported by entry of the following codes into eDMR:
Yes= 1 (Oil Sheen Visible)
No=0(Oil Sheen Not Visible).
4. If oil sheen or foam is visible(other than trace amounts),monitoring of pH and O&G is required until oil and/or foam
is abated,except as mitigated by BMPS.
5. Best Management Practices(BMPs): In lieu of monitoring pH and O&G,the Permittee may employ BMPs to
mitigate pollutant discharges to surface waters of the State. These practices shall include,at minimum,changing oil
absorbent pads Quarterly and routinely cleaning accumulated sediment from the bottom of the sump.After
implementing BMPs,the Permittee shall clearly document cleaning activities in the comments section of eDMR.
Page 3 of 7

NPDES Permit NC0027332
Other Conditions:
• This permit does not limit mechanical cleaning operations that do not contribute wastewater to the discharge.
Non-discharging cleaning operations may be conducted as often as necessary to ensure safety and proper
facility operation.
• The Permittee shall discharge no floating solids or foam visible in other than trace amounts.
• All samples collected shall accurately represent the physical and/or chemical character of each event discharging
to an outfall.
A. (2.) EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS
[15A NCAC 02B .0400 et seq.,02B.0500 et seq.] [15A NCAC 08G.0302-WPCS Class PCNC]
During the period beginning on the effective date of the permit and lasting until expiration, the Permittee
is authorized to discharge waters for sumps &drains (including powerhouse sumps& drains,wheel pit
drains, and gallery sumps & drains from Outfalls 003A & 003B. Such discharges shall be limited,
monitored and reportedl by the Permittee as specified below:
EFFLUENT CHARACTERISTICS LIMITS MONITORING REQUIREMENTS 1
[parameter codes] Monthly Daily Measurement Sample Sample
Average Maximum Frequency Type Location 2
Flow (MGD) 50050 Monitor& Report Semi-annually Estimate E
Temperate(°C)3 00010 Monitor&Report 3 Semi-annually Grab E
pH(Standard Units) 00400 Not<6.0 or>9.0 s.u. Semi-annually Grab E
Footnotes:
1. Electronic Reporting of Discharge Monitoring Reports(eDMRs):
a. The Permittee shall submit Discharge Monitoring Reports electronically using NC DWR's eDMR application system.
See Condition A.(4.).
b. Monitoring results obtained during the previous six(6)calendar months(semi-annual)shall be recorded
and reported in eDMR no later than the 30th day following the completed reporting period.The first DMR
is due on the 301 day of the month following the six(6)calendar months in which the permit was issued.
[Semi-annual reporting for these permitted outfalls is an exception to NPDES standard conditions found in
Part I,A.(6.)and Part II,D.(2.).wherein monthly reporting is indicated.]
2. Sample locations:E—Effluent
3. Effluent Temperature shall not increase receiving waters more than 2.8°C above natural ambient water
temperature.Facility discharge shall not cause receiving water temperatures to exceed a maximum of 29°C
[15A NCAC 02B.0211 (18)].
Conditions:
• All non-contact cooling water sample locations shall provide representative samples of the discharge and
require sampling prior to discharge commingling with any other waters or substances,such as stormwater or
surface water to enable characterization of a pollutant of concern.
• There shall be no discharge of floating solids or visible foam(other than trace amounts)in the effluent.
• All samples collected should be from a representative discharge event,a measurable discharge event that results in an
actual discharge from the permitted discharge outfall.
Page 4 of 7

NPDES Permit NC0027332
A. (3.) USE OF BIOCIDES - SPECIAL CONDITION
[G.S. 143-215, 143-215.1]
The Permittee shall obtain authorization from the Division prior to using any biocide that may be toxic to
aquatic life. The Permittee shall notify the Director in writing no later than 90 days prior to using any biocide
not already approved for this facility. The Permittee shall provide such notification by completing a Biocide
Worksheet, Form 101 to include a map indicating the receiving stream and the effluent discharge point.
Concentrations of additives to biocides such as chromium, copper,or zinc shall not exceed applicable water
quality standards or action levels in the receiving stream,as determined by calculations using the Biocide Work
Sheet, Form 101 and the Supplemental Analysis Worksheet.
A. (4.) ELECTRONIC REPORTING OF DISCHARGE MONITORING REPORTS
[G.S. 143-215.1(b)]
Federal regulations require electronic submittal of all discharge monitoring reports(DMRs)and
program reports. The final NPDES Electronic Reporting Rule was adopted and became effective on
December 21,2015.
NOTE: This special condition supplements or supersedes the following sections within Part II of this
permit(Standard Conditions for NPDES Permits):
• Section B. (11.)Signatory Requirements
• Section D. (2.)Reporting
• Section D.(6.)Records Retention
• Section E.(5.) Monitoring Reports
1. Reporting Requirements [Supersedes Section D.(2.) and Section E.(5.)(a)]
The permittee shall report discharge monitoring data electronically using the NC DWR's Electronic
Discharge Monitoring Report(eDMR) internet application.
Monitoring results obtained during the previous month(s) shall be summarized for each month and
submitted electronically using eDMR. The eDMR system allows permitted facilities to enter
monitoring data and submit DMRs electronically using the internet. The eDMR system may be
accessed at: https://deq.nc.gov/about/divisions/water-resources/edmr.
If a permittee is unable to use the eDMR system due to a demonstrated hardship or due to the facility being
physically located in an area where less than 10 percent of the households have broadband access,then a
temporary waiver from the NPDES electronic reporting requirements may be granted and discharge monitoring
data may be submitted on paper DMR forms(MR 1, 1.1,2, 3)or alternative forms approved by the Director.
Duplicate signed copies shall be submitted to the following address:
NC DEQ/Division of Water Resources/Water Quality Permitting Section
ATTENTION: Central Files
1617 Mail Service Center
Raleigh,North Carolina 27699-1617
See"How to Request a Waiver from Electronic Reporting"section below.
Regardless of the submission method,the first DMR is due on the last day of the month following the
issuance of the permit or in the case of a new facility,on the last day of the month following the
commencement of discharge.
Starting on December 21,2025, the permittee must electronically report the following compliance
monitoring data and reports,when applicable:
NPDES Permit NC0043583, Page 6 of 7
• Sewer Overflow/Bypass Event Reports
• Pretreatment Program Annual Reports,and
• Clean Water Act(CWA) Section 316(b)Annual Reports
Page 5 of 7

NPDES Permit NC0027332
The permittee may seek an electronic reporting waiver from the Division(see"How to Request a
Waiver from Electronic Reporting"section below).
2. Electronic Submissions
In accordance with 40 CFR 122.41(1)(9),the permittee must identify the initial recipient at the time of
each electronic submission. The permittee should use the EPA's website resources to identify the
initial recipient for the electronic submission.
Initial recipient of electronic NPDES information from NPDES-regulated facilities means the entity(EPA
or the state authorized by EPA to implement the NPDES program)that is the designated entity for
receiving electronic NPDES data [see 40 CFR 127.2(b)].
EPA plans to establish a website that will also link to the appropriate electronic reporting tool for each
type of electronic submission and for each state. Instructions on how to access and use the appropriate
electronic reporting tool will be available as well. Information on EPA's NPDES Electronic Reporting
Rule is found at:
https://www.federalregister.gov/documents/2015/10/22/2015-24954/nationalpollutant-discharge-
elimination-system-npdes-electronic-reporting-rule
Electronic submissions must start by the dates listed in the"Reporting Requirements"section above.
3.How to Request a Waiver from Electronic Reporting
The permittee may seek a temporary electronic reporting waiver from the Division. To obtain an
electronic reporting waiver,a permittee must first submit an electronic reporting waiver request to the
Division. Requests for temporary electronic reporting waivers must be submitted in writing to the
Division for written approval at least sixty(60)days prior to the date the facility would be required
under this permit to begin submitting monitoring data and reports. The duration of a temporary waiver
shall not exceed 5 years and shall thereupon expire. At such time,monitoring data and reports shall be
submitted electronically to the Division unless the permittee re-applies for and is granted a new
temporary electronic reporting waiver by the Division. Approved electronic reporting waivers are not
transferrable. Only permittees with an approved reporting waiver request may submit monitoring data
and reports on paper to the Division for the period that the approved reporting waiver request is
effective.
Information on eDMR and the application for a temporary electronic reporting waiver are found on the
following web page:
http://deq.nc.gov/about/divisions/water-resources/edmr
4. Signatory Requirements [Sup. To Section B. (11.)(b) and Supersedes Section B. (11.)(d)]
All eDMRs submitted to the permit issuing authority shall be signed by a person described in Part II,
Section B.(11.)(a)or by a duly authorized representative of that person as described in Part II, Section
B. (11.)(b). A person,and not a position,must be delegated signatory authority for eDMR reporting
purposes.
For eDMR submissions,the person signing and submitting the DMR must obtain an eDMR user
account and login credentials to access the eDMR system. For more information on North Carolina's
eDMR system,registering for eDMR and obtaining an eDMR user account,please visit the following
web page:
http://deq.nc.gov/about/divisions/water-resources/edmr
Page 6 of 7