NC0081931_Fact Sheet_20210122

Fact Sheet
NPDES Permit No. NCOO81931
Permit Writer/Email Contact: Cassidy Kurtz, [e-mail]
Date: January 22, 2021
Division/Branch: NC Division of Water Resources / NPDES Complex Permitting
Fact Sheet Template: Version 09Jan2017
Permitting Action:
❑X Renewal
❑ Renewal with Expansion
❑ New Discharge
❑ Modification (Fact Sheet should be tailored to mod request)
Note: A complete application should include the following:
• For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee
• For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET
tests.
• For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based
on industry category.
Complete applicable sections below. If not applicable, enter NA.
1. Basic Facility Information
Facility Information
Applicant/Facility Name:
Cube Yadkin Generation LLC / High Rock Powerhouse
Applicant Address:
PO Box 575, Badin, NC 28009
Facility Address:
3344 Bringle Ferry Road, Denton, NC 27239
Permitted Flow:
NA — Monthly Average = 61,840 gpd
Facility Type/Waste:
Industrial; SIC Code 4911 / Once -through cooling water
Facility Class:
Class I
Treatment Units:
Oil separator
Pretreatment Program (Y/N):
N
County:
Davidson
Region:
Mooresville
Briefly describe the proposed permitting action and facility background. -
Cube Yadkin Generation LLC has applied for an NPDES permit renewal for the High Rock Powerhouse
hydroelectric generation facility. This facility produces a yearly average of 151,503 MWhr, with a yearly
peak production of 310,980 MWhr. This facility has 5 outfalls.
Outfalls 001, 002, and 003: Thrust bearing cooling water
Outfalls 004: Stormwater from secondary containment for transformers
Page 1 of 7

Outfall 005: Wheelpits drainage, oil separator skimmer
The cooling water intake structure is described as follows:
Currently the facility withdraws cooling water from the Unit 1 & 2 scroll cases. Before the scroll cases
and the cooling water intakes, there are trash racks which are in front of the open head gates to prevent
debris from entering. The cooling water intakes are approximately 40 feet below the surface of the lake.
There is an 8-inch diameter, 1-inch mesh screen for each cooling water intake. Cooling water from the
Unit 1 and 2 scroll cases flows in a 12-inch diameter pipe and into 1/16-inch duplex manual strainers and
an automatic 1/16-inch strainer in parallel. From there two pumps are used to distribute the cooling water
through 6-inch diameter pipes for the thrust bearing cooling coils for each unit. The thrust bearing coiling
coils water discharge outfalls are as follows: Unit 1 — Outfall 001, Unit 2 — Outfall 002, and Unit 3 —
Outfall 003. The manual strainers are cleaned twice per week minimum. This facility discharges
approximately 54,840 gpd cooling water.
2. Receiving Waterbody Information
Receiving Waterbody Information
Outfalls/Receiving Stream(s):
Outfalls 001, 002, 003, 004, 005 — Yadkin River
Stream Segment:
12-(136.3)
Stream Classification:
WS-IV and B CA
Drainage Area (mi2):
--
Summer 7Q10 (cfs):
--
Winter 7Q10 (cfs):
--
30Q2 (cfs):
--
Average Flow (cfs):
--
IWC (% effluent):
--
303(d) listed/parameter:
Yes, the segment is listed in the 2018 303(d) for Fish
Consumption Advisory (PCB Fish Tissue Advisory)
Subject to TMDL/parameter:
Yes- State wide Mercury TMDL implementation. (Mercury
discharges not expected for industry)
Sub-basin/HUC:
03-07-08 / flUC 03040103
USGS Topo Quad:
E18SW
3. Effluent Data Summary
Effluent data for Outfalls 001, 002, 003 and 005 is summarized below for the period of April 2015
through October 2019.
Table 1. Effluent Data Summary Outfall 001
Parameter
Units
Average
Max
Min
Permit Limit
Flow
MGD
0.0173
0.0173
0.0173
pH
SU
7.53
7.9
6.9
6.0 < pH < 9.0
Page 2 of 7

Temperature ° C 1 18.9 23.9 9.8
Table 2. Effluent Data Summary Outfall 002
Parameter
Units
Average
Max
Min
Permit Limit
Flow
MGD
0.0173
0.0173
0.0173
pH
SU
7.42
7.8
6.9
6.0 < pH < 9.0
Temperature
° C
19.2
23.6
9.7
Table 3. Effluent Data Summary Outfall 003
Parameter
Units
Average
Max
Min
Permit Limit
Flow
MGD
0.0173
0.0173
0.0173
pH
SU
7.55
7.9
7.0
6.0 < pH < 9.0
Temperature
° C
19.4
24.5
10.9
Table 4. Effluent Data Summary Outfall 005
Parameter
Units
Average
Max
Min
Permit Limit
Flow
MGD
0.0173
(only 1 value reported)
pH
SU
7.8
(only 1 value reported)
Oil & Grease
mg/L
< 2.6
(only 1 value reported)
MA 15.0 mg/L
DM 20.0 mg/L
MA -Monthly Average, WA -Weekly Average, DM -Daily Maximum, DA-Daily Average
4. Instream Data Summary
Instream monitoring may be required in certain situations, for example: 1) to verify model predictions
when model results for instream DO are within 1 mg/1 of instream standard at full permitted flow; 2) to
verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other
instream concerns. Instream monitoring may be conducted by the Permittee, and there are also
Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in
which case instream monitoring is waived in the permit as long as coalition membership is maintained).
If applicable, summarize any instream data and what instream monitoring will be proposed for this
permit action: The current permit contains no instream monitoring requirements.
Is this facility a member of a Monitoring Coalition with waived instream monitoring (YIN): NO
Name of Monitoring Coalition: NA
5. Compliance Summary
Summarize the compliance record with permit effluent limits (past 5 years): The facility reported no limit
violations since March 2014.
Summarize the compliance record with aquatic toxicity test limits and any second species test results
(past 5 years): There are no toxicity testing requirements in the permit.
Page 3 of 7

Summarize the results from the most recent compliance inspection: The last facility inspection conducted
in May 2016 reported that the facility was observed to be well operated and maintained.
6. Water Quality -Based Effluent Limitations (WQBELs)
Dilution and Mixing Zones
In accordance with 15A NCAC 213.0206, the following streamflows are used for dilution considerations
for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic
Life; non -carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH).
If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results): NA
If applicable, describe any mixing zones established in accordance with I5A NCAC 2B. 0204(b): NA
Oxygen -Consuming Waste Limitations
Limitations for oxygen -consuming waste (e.g., BOD) are generally based on water quality modeling to
ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits
(e.g., BOD= 30 mg/1 for Municipals) may be appropriate if deemed more stringent based on dilution and
model results.
Ifpermit limits are more stringent than TBELs, describe how limits were developed: There are no limits
for BOD in the permit.
Ammonia and Total Residual Chlorine Limitations
Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of
1.0 mg/1(summer) and 1.8 mg/1(winter). Acute ammonia limits are derived from chronic criteria,
utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non -Municipals.
Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection
of aquatic life (17 ug/1) and capped at 28 ug/1(acute impacts). Due to analytical issues, all TRC values
reported below 50 ug/1 are considered compliant with their permit limit.
Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: There are no
limits for ammonia or TRC in the permit.
Reasonable Potential Analysis (RPA) for Toxicants
If applicable, conduct RPA analysis and complete information below. -- NA. A reasonable potential
analysis was not conducted because there is no available effluent toxicant data/ not applicable for these
waste streams.
Toxici , Testing Limitations
Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in
accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits
issued to Major facilities or any facility discharging "complex" wastewater (contains anything other than
domestic waste) will contain appropriate WET limits and monitoring requirements, with several
exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in
NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test
failure.
Describe proposed toxicity test requirement: There are no toxicity testing requirements in the permit.
Mercury Statewide TMDL Evaluation
Page 4of7

There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply
with EPA's mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a
wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and
industrial facilities with known mercury discharges. Given the small contribution of mercury from point
sources (-2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source
control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/1) will
receive an MMP requirement. Industrials are evaluated on a case -by -case basis, depending if mercury is a
pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed
the WQBEL value (based on the NC WQS of 12 ng/1) and/or if any individual value exceeds a TBEL
value of 47 ng/l.
Describe proposed permit actions based on mercury evaluation: NA. This industry does not have known
mercury discharges.
Other TMDL/Nutrient Management Strategy Considerations
If applicable, describe any other TNDDLs/Nutrient Management Strategies and their implementation
within this permit: NA
Other WOBEL Considerations
If applicable, describe any other parameters of concern evaluated for WQBELs: NA
If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall
comply with in order to protect the designated waterbody: NA
If applicable, describe any compliance schedules proposed for this permit renewal in accordance with
15A NCAC 2H 0107(c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: NA
If applicable, describe any water quality standards variances proposed in accordance with NCGS 143-
215.3(e) and 15A NCAC 2B. 0226 for this permit renewal: NA
7. Technology -Based Effluent Limitations (TBELs)
Industrials
Describe what this facility produces: Hydroelectric power
List the federal effluent limitations guideline (ELG) for this facility: NA
If the ELG is based on production or flow, document how the average production/flow value was
calculated. NA
For ELG limits, document the calculations used to develop TBEL limits: NA
If any limits are based on best professional judgement (BPJ), describe development: Oil and Grease
limits for Outfall 005 have been in the permit since 2018 and are based on BPJ.
Document any TBELs that are more stringent than WQBELs: NA
Document any TBELs that are less stringent than previous permit: NA
8. Antidegradation Review (New/Expanding Discharge)
The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not
degrade water quality. Permitting actions for new or expanding discharges require an antidegradation
review in accordance with 15A NCAC 213.0201. Each applicant for a new/expanding NPDES permit
Page 5 of 7

must document an effort to consider non -discharge alternatives per 15A NCAC 2H.0105(c)(2). In all
cases, existing instream water uses and the level of water quality necessary to protect the existing use is
maintained and protected.
If applicable, describe the results of the antidegradation review, including the Engineering Alternatives
Analysis (EAA) and any water quality modeling results: NA
9. Antibacksliding Review
Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(1) prohibit
backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a
reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations
may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL
limits, or WQBELs may be less stringent based on updated RPA or dilution).
Are any effluent limitations less stringent than previous permit (YESINO): NO
If YES, confirm that antibacksliding provisions are not violated: NA
10. Monitoring Requirements
Monitoring frequencies for NPDES permitting are established in accordance with the following
regulations and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 213.0500; 2)
NPDES Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance,
Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best
Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not
considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti -
backsliding prohibitions would not be triggered by reductions in monitoring frequencies.
For instream monitoring, refer to Section 4.
11. Electronic Reporting Requirements
The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective
December 21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports
(DMRs) electronically. While NPDES regulated facilities would initially be required to submit additional
NPDES reports electronically effective December 21, 2020, EPA extended this deadline from December
21, 2020, to December 21, 2025. The current compliance date, effective January 4, 2021, was extended as
a final regulation change published in the November 2, 2020 Federal Register. This permit contains the
requirements for electronic reporting, consistent with Federal requirements.
12. Summary of Proposed Permitting Actions
Table. Current Permit Conditions and Proposed Changes: Outfalls 001, 002, 003
Parameter
Current Permit
Proposed Change
Basis for
Condition/Change
Flow
Monitor Annually
No change
15A NCAC 2B .0505
Temperature
Monitor Annually
No change
WQBEL. State WQ
standard, 15A NCAC
2B .0200
pH
6.0 — 9.0 SU
No change
WQBEL. State WQ
standard, 15A NCAC
2B .0200
Page 6 of 7

Electronic Reporting
Required
No change
In accordance with
EPA Electronic
Reporting Rule 2015.
MGD — Million gallons per day, MA — Monthly Average, WA — Weekly Average, DM — Daily Max
Table. Conditions and Proposed Changes: Outfall 005
Parameter
Current Permit
Proposed Change
Basis for
Condition/Change
Flow
Monitor Annually
No change
15A NCAC 2B .0505
Oil and Grease
MA 15.0 mg/L
No change
State WQ standard,
DM 20.0 mg/L
15A NCAC 2B .0200;
BPJ
pH
6.0 - 9.0 SU
No change
WQBEL. State WQ
standard, 15A NCAC
2B .0200
Electronic Reporting
Required
No change
In accordance with
EPA Electronic
Reporting Rule 2015.
MGD — Million gallons per day, MA — Monthly Average, WA — Weekly Average, DM — Daily Max
13. Public Notice Schedule
Permit to Public Notice: 6/25/2020
Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following
the publication date of the public notice. Any request for a public hearing shall be submitted to the
Director within the 30 days comment period indicating the interest of the party filing such request and the
reasons why a hearing is warranted.
14. NPDES Division Contact
If you have questions regarding any of the above information or on the attached permit, please contact
Cassidy Kurtz at [phone] or via email at [e-mail].
15. Fact Sheet Addendum (if applicable)
Were there any changes made since the Draft Permit was public noticed (Yes/No): YES
If Yes, list changes and their basis below:
The permittee noted that TSS monitoring for Outfall 005 was removed during a modification in
2018. Special Condition A. (4.) was corrected to remove the TSS monitoring requirement.
A notation was made concerning the Electronic Reporting Rule — Phase 2 Extension.
extended the Phase 2 deadline from December 21, 2020, to December 21, 2025, effective
January 4, 2021. The current compliance date has been extended to reflect this change
[See A.(5.)].
16. Fact Sheet Attachments (if applicable)
NA
Page 7 of 7

42008346
J000663148
AFFIDAVIT OF PUBLICATION
STATE OF NORTH CAROLINA LEXINGTON, NC June 25, 2020
DAVIDSON COUNTY
I, Lynn Bowers OF THE DISPATCH, A NEWSPAPER PUBLISHED IN THE CITY OF LEXINGTON, COUNTYAND STATE
AFORESAID, BEING DULY SWORN, SAYS THE FOREGOING LEGAL OF WHICH THE ATTACHED IS A TRUE COPY,
WAS PUBLISHED IN SAID NEWSPAPER ONCE, BEGINNING THE 25th DAY OF June, 2020.
PUBLICATION FEE: $ 101.43
(SEAL)
SWORN TO AND SUBSCRIBED BEFORE ME,
MY COMMISSION EXPIRES ' d
Ad Copy:
Public Notice
North Carolina
Environmental Management
Commission/NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of Intent to Issue a
NPDES Wastewater Permit
NCO081931 High Rock
Powerhouse
The North Carolina
Environmental Management
Commission proposes to issue
a NPDES wastewater
discharge permit to the
person(s) listed below. Written
comments regarding the
proposed permit will be
accepted until 30 days after the
publish date of this notice. The
Director of the NC Division of
Water Resources (DWR) may
hold a public hearing should
there be a significant degree of
public interest. Please mail
comments and/or information
requests to DWR at the above
address. Interested persons
may visit the DWR at 512 N.
Salisbury Street, Raleigh, NC
to review information on file.
Additional information on
NPDES permits and this notice
may be found on our website:
http://deg.nc.gov/about/division
s/water-resources/wate r-
THIS�DAY OF �l7lMQ- `a,6aD
resources- ermits/wastewater-
branch/npdes-
wastewater/ ublic-notices or by
calling [phone].
Cube Yadkin Generation LLC
requested renewal of permit
NCO081931 for High Rock
Powerhouse in Davidson
County; this facility discharge is
once -through cooling water
and stormwater to Yadkin
River, Yadkin River Basin.
June 25, 2020
tt I CI IWoex,��%',,
Notary Public
Rowan County My CCornissi n ExpTres_

42008346
J000663148
AFFIDAVIT OF PUBLICATION
STATE OF NORTH CAROLINA LEXINGTON, NC June 25, 2020
DAVIDSON COUNTY
I, Lynn Bowers OF THE DISPATCH, A NEWSPAPER PUBLISHED IN THE CITY OF LEXINGTON, COUNTY AND STATE
AFORESAID, BEING DULY SWORN, SAYS THE FOREGOING LEGAL OF WHICH THE ATTACHED IS A TRUE COPY,
WAS PUBLISHED IN SAID NEWSPAPER ONCE, BEGINNING THE 25th DAY OF June, 2020.
PUBLICATION FEE: $ 101.43
ty, Ihn
f . G1e�_' L (SEAL)
SWORN TO AND SUBSCRIBED, BEFORE ME,
MY COMMISSION EXPIRES
Ad Copy
Public Notice
North Carolina
Environmental Management
Commission/NPDES Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Notice of Intent to Issue a
NPDES Wastewater Permit
NCO081931 High Rock
Powerhouse
The North Carolina
Environmental Management
Commission proposes to issue
a NPDES wastewater
discharge permit to the
person(s) listed below. Written
comments regarding the
proposed permit will be
accepted until 30 days after the
publish date of this notice. The
Director of the NC Division of
Water Resources (DWR) may
hold a public hearing should
there be a significant degree of
public interest. Please mail
comments and/or information
requests to DWR at the above
address. Interested persons
may visit the DWR at 512 N.
Salisbury Street, Raleigh, NC
to review information on file.
Additional information on
NPDES permits and this notice
may be found on our website:
http://deg.nc.gov/about/division
s/water-resources/water-
THIS � DAY OF � ) lkA-0— Oi6`aO
resources -perm its/wastewater-
branch/ngdes-
wastewater/public-notices,or by
calling [phone].
Cube Yadkin Generation LLC
requested renewal of permit
NCO081931 for High Rock
Powerhouse in Davidson
County; this facility discharge is
once -through cooling water
and stormwater to Yadkin
River, Yadkin River Basin.
June 25, 2020
\\\\\\\O\PMI ICI I! /��//'i
CD
Notary Public
Rowan County —
=My Conimissrpn Expires=
,�//Njj I I I I j I ON

Kurtz, Cassidy
From: Cook, Clinton
Sent: Wednesday, July 22, 2020 5:01 PM
To: Kurtz, Cassidy
Subject: FW: Cube Yadkin Generation Draft NPDES Permits
Attachments: 76775 Draft package.pdf, 81931 Draft package.pdf, 81949 Draft package.pdf; 81957 -
Draft package.pdf
Hello Cassidy,
I appreciate the opportunity to review the subject draft NPDES permits and have included my response below in bold to
satisfy the new paperless standards.
I concur with issuance of the above permits as I have no appreciable expertise in implementation of the Clean Water
Act requirements and have minimal understanding of the information provided. As a result, I have no basis for
opposing the permits.
Please note the following:
For NPDES Permit NCO076775 — Falls Powerhouse, the nearest downstream raw water intake for a public water system
is associated with the Town of Norwood and is located approximately 12.6 miles downstream.
For NPDES Permit NCO081931— High Rock Powerhouse, the nearest downstream raw water intake for a public water
system is associated with the Town of Denton and is located approximately 500 feet downstream.
For NPDES Permit NCO081949 —Tuckertown Powerhouse, the nearest downstream raw water intake for a public water
system is associated with the City of Albemarle and is located approximately 2.1 miles downstream.
For NPDES Permit NCO081957 — Narrows Powerhouse, the nearest downstream raw water intake for a public water
system is associated with the Town of Norwood and is located approximately 15 miles downstream.)
Please also note that because the Town of Denton's water system is located within the Winston Salem Region and the
intake for Denton is downstream of the outfalls associated with NPDES Permit NCO081931 (High Rock Powerhouse), I've
asked Jeff Bryan, PE, Assistant Regional Engineer, Public Water Supply Section, Winston Salem Regional Office to review
and comment on the draft permit. Mr. Bryan's comments are below in bold:
The Public Water Supply Section concurs with issuing the permit provided the permittee properly operates and
maintains the facilities, the stated effluent limits are met, and the discharge does not contravene the designated
water quality standards.
If you have any questions or need any additional information, please let me know.
Thanks,
Clint
Clinton O. Cook, PE
Regional Engineer
Division of Water Resources — Public Water Supply Section
North Carolina Department of Environmental Quality

704 663 1699 office
704 663 6040 fax
cIinto n.coo kC�ncdenr.gov
Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, NC 28115
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Kurtz, Cassidy
Sent: Friday, June 26, 2020 3:02 PM
To: Cook, Clinton <[e-mail]>
Subject: Cube Yadkin Generation Draft NPDES Permits
Hi Clinton,
Please find attached the draft NPDES permits for Cube Yadkin Generation LLC's four hydroelectric facilities:
- NC0076775 — Falls Powerhouse
- NC0081931 — High Rock Powerhouse
- NC0081949 —Tuckertown Powerhouse
- NC0081957 — Narrows Powerhouse
These facilities all discharge to the Yadkin River. Please review and respond with any comments within 30 days. Thank
you!
Best,
Cassidy Kurtz
Engineer
NC DEQ / Division of Water Resources / Water Quality Permitting
NPDES Complex Permitting / Wastewater Branch
[phone] office
[phone] main office
cassidv.kurtz(d)ncdenr.aov
Physical Address: 512 North Salisbury St., Raleigh, NC 27604
Mailing Address: 1617 Mail Service Center, Raleigh, NC 27699-1617
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.