NCG500657_NOV-2019-FK-0002 Response_20190813

f�KE
ENERGY.
August 19, 2019
Mr. Tim Heim
North Carolina Department of Environmental Quality
Division of Water Resources
Asheville Regional Office
2090 U.S. Highway 70
Swannanoa, North Carolina 28778
Randy Herrin
VP FHO Regulated Renewables
Duke Energy
Cowans Ford
257 Duke Lane
Stanley NC 28464
[phone]
Randy Herrin@duke-energy com
RE: Nantahala River Fish Kill — Nantahala Hydro Project Spillway Release
(NOV-2019-FK-0002)
Dear Mr. Heim:
Duke Energy Carolinas, LLC ("Duke Energy") writes in response to the above -referenced
Notice of Violation ("NOV") dated August 6, 2019 regarding the Nantahala Hydroelectric Project
(FERC Project No. 2692) (the "Project").' The Federal Energy Regulatory Commission ("FERC")
issued the Project license on February 8, 2012, which incorporates the Hydro Project Maintenance
and Emergency Protocol ("HPMEP"), the 401 Water Quality Certification issued by the North
Carolina Department of Environmental Quality, Division of Water Resources ("DWR"), and
requirements to manage lake levels and release recreational flows. FERC has the authority to
enforce the license terms, and Duke Energy sent a notification about the forced outage of the
Nantahala Hydro Station which led to this event to FERC on July 29, 2019. A copy of this
notification is attached as Appendix A.
1. Conditions Under Which the Warm Water Flow Release Occurred
On July 23, 2019 at 08:46, failure of electrical components in the Project's switchyard
resulted in a forced station outage. Although Duke Energy worked diligently to repair the failed
electrical components, since the outage was affected by two simultaneous failures, it took longer
to define the total scope of the repair and locate the additional spare parts. After the Nantahala
hydro unit failed to start, Duke Energy was required to enact the HPMEPz to provide whitewater
recreation flow releases. Specifically, for the next five days, from July 24-28, 2019, Duke Energy
The NOV subject line refers to the Franklin Project, but this event occurred at the Nantahala Project.
Specifically, HPMEP's General Approach to Abnormal Situations, Forced Hydro Unit Outages (Sections A.l .b.
(Mitigating Actions) and A.2.b (Communication with Resource Agencies and Affected Parties).

Mr. Tim Heim
August 19, 2019
Page 2
periodically opened a spillway gate at the Nantahala Dam. This resulted in warmer water being
released to the Nantahala River than is released through the hydro unit.
2. Response. Monitoring,and HPMEP
The HPMEP requires a good -faith endeavor by Duke Energy to provide a portion of the
scheduled recreation flow releases using a spillway gate if the hydro unit is unavailable during a
Critical Commercial Whitewater Recreation Period (defined in the HPMEP and including among
other periods, any period between 9 AM and 5 PM from July I through August 15). Because
releases from a spillway gate are wanner than releases from the Nantahala hydro unit and can
potentially lower dissolved oxygen ("DO") levels, from Friday, July 26 to Sunday, July 28, Duke
Energy dispatched fisheries scientists and water quality experts to monitor water quality and the
fishery in the Nantahala River and Bypassed Reach. Data collected during the monitoring effort
indicated DO levels did not drop below the 5.0 mg/I level, which, when combined with water
temperatures above 20' C, would have required cessation of the whitewater flow releases from the
spillway gate per the HPMEP. As information, the maximum water temperature observed from a
continuous recorder located at Nantahala Dam Rd. along the left bank ascending side of the
channel where the road crosses the bypassed reach was 25.4° C. The lowest DO level measured
throughout the reach was 6.71 mg/L at the same location.
On Saturday evening, July 27, Duke Energy staff consulted with our on -site scientists to
determine the potential impacts of a planned whitewater recreational flow release for the morning
of July 28. Based on all available information, Duke Energy decided to make the scheduled flow
release on Sunday morning. Duke Energy began the whitewater recreational flow release at 05:00
as planned and was scheduled to close the spillway gate at 13:00. At approximately 10:30,
however, our fisheries scientists observed impacts to the fishery and reported a fish kill. Duke
Energy promptly dispatched a hydro technician, who closed the spillway gate at approximately
1 1:15. Based on an analysis of the data, it was determined the fish mortalities were not from
depressed DO levels but from thermally -induced stress. Also, beginning on July 28 at
approximately 11:00, Duke Energy increased flow to the Nantahala River by both operating the
Queens Creek Project (FERC Project No. 2694) hydro unit as well as opening the Queens Creek
spill valve to provide cooler water.
Historically, the Nantahala hydro unit has been very reliable, and prior to the July 23-28
outage, Duke Energy has never had to invoke Section A of the HPMEP since FERC issued the
license in February2012. In the July 23-28 outage, however, two aspects of the HPMEP were not
strictly followed. First, the HPMEP requires environmental monitoring to occur during the
spillway gate flow release with temperatures above 20' C at the gate sill, but Duke Energy did not
have environmental personnel in the Bypassed Reach monitoring until the third day of the gate
releases. Second, gate releases occurred on five consecutive days, whereas the HPMEP states to
avoid spillway releases occurring on more than two consecutive days. Duke Energy has evaluated
these two aspects and has developed a corrective action plan, which is described in more detail in
Section 4, below.

Mr. Tim Heim
August 19, 2019
Page 3
All monitoring data from this period is attached as Appendix B.
3. Fish Mortality Estimate
Fish mortality estimates were generated from protocols and methods detailed in the
American Fisheries Society Publication Investigation and valuation of Fish Kills, Special
Publication 24 (1992). These are the same protocols and methods used by DWR and the North
Carolina Wildlife Resources Commission ("WRC") for fish kill investigations.
Complete enumeration was impractical given the linear extent of the affected area and the
presence of recreational flows throughout much of the day. Approximately 16 river miles of the
Nantahala River and major adjacent tributaries, stretching from the Nantahala Dam to Lake
Fontana, were evaluated during this investigation. The best opportunity to look for stressed and
dead fish was in the morning hours prior to the arrival of recreational flows. During recreational
flows, water depths and velocities made it difficult to see fish in the water column and virtually
eliminated slack water areas where stressed and dead fish could accumulate and be
observed. These conditions also made it unsafe for wading and instream monitoring. Because of
these limitations, a modified area sampling approach was employed.
Based on this methodology, the estimated number of fish killed is 246.
4. Corrective Action Plan
Duke Energy consulted with resource agencies and other stakeholders listed in the
applicable section of the HPMEP on August 1 to evaluate the impacts of the fish kill and begin
discussing potential options to lessen impacts from this and future outages. WRC indicated they
planned to stock the Nantahala River with surplus hatchery fish in species ratios and numbers
consistent with previous 2019 stocking events. In support of this effort, on August 15, 2019, Duke
Energy contributed $7,5003 to more than equal the expenses of rearing, incidentals, and stocking
5,000 trout that were released in the Nantahala River after the fish kill.` The lake level management
and whitewater flow releases resulted in an estimated 246 fish deaths, so this contribution
sufficiently replaced the impacted fish.
Duke Energy has determined the approach for mitigative actions and communication as
outlined in the HPMEP for a forced outage of the Nantahala hydro unit is directionally correct and
does not require revision. However, implementation of the HPMEP could be improved by
providing additional guidance to Duke Energy staff for interpreting requirements and coordinating
with on -site crews. The following plan provides this additional guidance:
a. To ensure awareness and accelerate mobilization, a notification email will be sent by
License Compliance staff to all supporting Duke Energy departments on the same day the
' The actual cost of the restocked fish provided by the WRC was $6,400.
Based on an email from the WRC, about half of the stocking occurred on August 6 and half on August 12.

Mr. Tim Heim
August 19, 2019
Page 4
HPMEP is enacted for a forced outage of the Nantahala hydro unit during the Peak
Recreation Season (April through October).
b. To enhance effectiveness of real-time field considerations, if temperatures at the spillway
gate sill exceed 20' C, Duke Energy will:
1) Coordinate with the WRC to:
i. Determine when trout were last stocked or if stocking is planned to occur in the
Nantahala River during the time of the forced outage
ii. Pursue opportunities for joint monitoring of the Nantahala River and Bypassed
Reach by WRC crews and Duke Energy crews
iii. Ensure effective communications between WRC staff and Duke Energy staff (e.g.,
establish a schedule for regular conference calls to share information on water
quality and observations of the trout fishery condition during the event)
2) Incorporate the following decisional parameters for making spillway gate releases in
response to Nantahala hydro unit outages:
i. Make spillway gate releases as needed regardless of temperature, DO or other
conditions, to protect the integrity of the dam and public safety, including but not
limited to making spillway gate releases to prepare for a forecasted high inflow
event, to respond to an actual high inflow event or to prevent lake levels from
exceeding the Normal Maximum Elevation
ii. Allow lake levels to trend up if needed above the Normal Target Elevation but not
above the Normal Maximum Elevation
iii. Do not make a spillway gate release for whitewater recreation on the day the forced
outage of the hydro unit begins
iv. Do not make a spillway gate release for whitewater recreation until temperature, DO,
and fisheries monitoring in the field has been implemented by Duke Energy crews
v. Do not make a spillway gate release for whitewater recreation if less than two
calendar days have passed since the WRC last stocked trout in the Nantahala River
or the Bypassed Reach
vi. Consider reducing the duration of spillway gate releases for whitewater recreation
after consulting with the stakeholders listed in the applicable section of the HPMEP.'
vii. Do not make spillway gate releases for whitewater recreation for more than two
consecutive days
HPMEP's General Approach to Abnormal Situations, Forced Hydro Unit Outages (Section A.2.b (Communication
with Resource Agencies and Affected Parties)).

Mr. Tim Heim
August 19, 2019
Page 5
viii. If spillway gate releases for whitewater recreation are made for two consecutive
days, have at least one day without spillway gate releases before restarting gate
releases for Whitewater recreation releases.
3) Incorporate the following decisional parameters for augmenting cool water flow:
i. If the Whiteoak Creek Pond has significant levels of accumulated sediment, rather
than opening its sluice gate, close its penstock head gate to allow water to overflow
its diversion dam.
ii. Fully open the Minimum Flow Valves on the Nantahala and Whiteoak Creek
Penstocks.
iii. Operate Queens Creek Hydro Station (FERC Project No. P-2694) at maximum gate
setting if available, but do not draw the lake down below its Normal Operating
Range.
iv. Consider opening the spill valve at Queens Creek Dam.
5. Additional Information
Throughout the spillway gate flow release period, Duke Energy stayed in close contact
with stakeholders through daily emails from our community relations liaison to provide updates
on flow releases and progress toward restoring the hydro station to service.
Additionally, most of the affected fish were stocked brook trout, which may have been
unusually susceptible to high water temperatures. Just before the outage, on July 23, the WRC
stocked 4,500 trout in the Nantahala Bypassed Reach and River. The stocked trout may not have
had time to acclimate from hatchery to actual river conditions. No non -trout fish species
mortalities were documented.
Further, although it was not the driving factor in Duke Energy's decisions, rescheduling
the recreational flow releases would have had a significant negative economic impact on the area,
as rafting and tourism are the main contributors to the economy during the summer months.
Because vacation season is coming to an end, rescheduling the recreational flow releases would
not have provided the same economic benefit to the region.
Finally, any non-compliance on the part of Duke Energy was wholly unintentional, and
Duke Energy in no way profited financially from the subject spillway gate flow releases. In fact,
Duke Energy loses power generation opportunities when it releases water without passing it
through the hydro station.
If you have additional questions concerning this event or the information provided in this
letter, please contact Alan Stuart at 980-373-2079 or [e-mail].

Mr. Tim Heim
August 19, 2019
Page 6
Sincerely,
1411k'� �-
Randy C. Herrin, PE
VP, Regulated Renewables
Duke Energy
Enclosures
cc: Alan Stuart, Duke Energy (with enclosures)

Appendix A

A;'ENERGY,&DUKE
July 29, 2019
The Honorable Kimberly D. Bose, Secretary
Federal Energy Regulatory Commission
888 First Street, N.E.
Washington, DC 20426
WATER STRATEGY, HYDRO
LICENSING AND LAKE
SERVICES
Duke Energy Corporation
526 South Church Street/EC12Y
Charlotte NC 28202
RE Duke Energy Carolinas, LLC
Nantahala Hydroelectric Project No. P-2692
Notification of Forced Station Outage, Initiation of the Hydro Project Maintenance and Emergency Protocol
and Missed Recreational Whitewater Flow Release per License Article 405
Dear Secretary Bose:
Duke Energy Carolinas, LLC (Duke Energy) is notifying the Federal Energy Regulatory Commission (FERC) of a
forced station outage and initiation of the Hydro Project Maintenance and Emergency Protocol (HPMEP) for the
Nantahala Hydroelectric Project (FERC Project No. 2692) (Project). On July 23, 2019 at 08:46, failure of electrical
components in the Project's switchyard resulted in a forced station outage. Immediately after the hydro unit failed
to start, Duke Energy began enacting the HPMEP in accordance with the section entitled "General Approach to
Abnormal Situations; Section A- Hydro Unit Outages" to manage lake levels and to provide whitewater recreation
flow releases. Because of the forced outage, the whitewater recreation flow release required by Article 405 was not
made on July 23, 2019 and will be made up at another time this calendar year.
In accordance with the FERC license and the HPMEP, Duke Energy partially opened a spillway gate at the
Nantahala Dam periodically as required for lake level management and to provide whitewater recreation flow
releases for five days from July 24-28, 2019. Duke Energy communicated daily with the state and federal resource
agencies as well as recreation stakeholders on the progress of repairs to the failed equipment and plans to provide
whitewater recreation flow releases from the spillway gate throughout the forced outage (Enclosure 1).
Since flow releases from the spillway gate are warmer than flow releases from the hydro unit and potentially can
produce lower than normal dissolved oxygen (DO) levels beginning Friday July 26, Duke Energy dispatched
fisheries biologists and water quality experts to monitor water quality and the fishery in the Nantahala River and
Bypassed Reach. Data collected during the monitoring effort indicated DO levels did not drop below the 5.0 mg/I
level which would require cessation of the whitewater flow releases from the spillway gate. Further, the maximum
water temperature from a continuous recorder was 26.0° C Duke Energy made the decision not to adjust the
Whiteoak Creek Diversion Dam sluice gate to release additional flow to the Bypassed Reach due to high levels of
sediment in the impoundment resulting from run-off from heavy rains experienced in the region over the last nine
months. However, Duke Energy did increase flow to the Nantahala River by operating the hydro unit and opening
the spill valve at the Queens Creek Project (FERC Project No. 2694) to provide cooler water. In addition, Duke
Energy provided real-time messaging updates on its website and phone messaging systems
On Saturday evening, July 27''', Duke Energy staff consulted with our on -site scientists to determine the potential
impacts of a planned whitewater recreational flow release for the morning of July 28". Based on the data collected,
observations, and findings from monitoring on July 271 provided by the scientists, the information supported
making the scheduled flow release on Sunday morning. Duke Energy began the whitewater recreational flow release
at 5:00 as planned and was scheduled to close the spillway gate at 13:00. At approximately 10:30 our fisheries

The Honorable Kimberly D. Bose, Secretary
July 29, 2019
Page 2 of 2
biologists observed impacts not from depressed DO levels but from thermal stress (warmer temperatures) to the
fishery and reported a fish kill. Duke Energy began making necessary arrangements to close the spillway gate upon
hearing of the fish kill event. At approximately 11:15, a technician closed the spillway gate thus halting the
whitewater flow release for that day. Duke Energy has been in contact with state and federal resource agencies and
continues to monitor site conditions regarding the fish kill. Duke Energy will consult with resource agencies and
other stakeholders as stated in the HPMEP to develop and implement a fish restoration plan and consider options
suggested by the consulting parties which could lessen impacts this and future outages. Further, Duke Energy will
coordinate with agencies, rafting companies and organizations to schedule a make-up date for the missed
recreational flow release of July 23'
The Nantahala generating unit was returned to service on July 28, 2019 at 15:39 ending the need for Duke Energy
to implement the HPMEP.
Please direct questions to Alan Stuart (Alan,[e-mail]) at 980-373-2079 or Lynne Dunn
([e-mail]) at 980-701-7043
Sincerely,
J_// _717�
Jeffrey G. Lineberger, PE
Director, Water Strategy and Hydro Licensing
Duke Energy
Enclosure
cc w/enclosure:
Kevin Barnett, NC Division of Water Resources
Chris Goudreau, NC Wildlife Resources Commission
Fred Tarver, NC Division of Water Resources
Bryan Tompkins, US Fish and Wildlife Service
Kevin Colburn, American Whitewater
William Irving, Nantahala Gorges Association
Mike Wilkins, US Forest Service
Alan Stuart, Duke Energy
Phil Fragapane, Duke Energy
Lynne Dunn, Duke Energy
Eddie Duncan, Duke Energy
Alan Madewell, Duke Energy

Enclosure Example of Daily Communication with resource agencies and stakeholders
From: Leatherman, wa A
To: Juliet Jdcot3sen Kastr2df; Bobbve Miller. t:ethv Kennedy; Chn5 LAey; Jack Wi a; Jeff Carter: John Griffin; K�1]
Kaslorff; t t I ni Mr II h• Sue Matz; LQhng heyy388C�3o1 com; colecoffernu gmail.com; nrnl krUireats Crim,;
(nark ThcmdsP�¢�e Inn l3aftin0 Comoanv; lhaastdwcu edu; Jeremiah Haas; Kay Tufts;
mominagddleirinrafting coin; raft _ Orolinacu ri t ters.comraftu1g(a)whne water." ;
r ❑i riv rkroniaQmaiLcQm; v II (ar Ili h n raver . m; Eli Fowler; Daniel Hales; D?w!}.uI L NdLh�+n f5;
Saviors, Tllgmas t F5; Yahoo; Njclipla5 McCullough; w1lltr1!-,ttnQQU11Ook r m Tanner
Giesey; $ryan Tompkins (bryan tomokmsiaftL.grLyl;Fred larver__ffred.ta�enu-Qov1; Barnett. Kevin
k vin.lr,Jrn2Cii�nsdenr.govi; Goudreau. Chris; DeWeese ]r.. Jerry Lpe; Tim Warr gnlblsy_Or_k_hik;�h�inc� l canal;
Urgm martin (alarkaexedi,tlyctmadsom}; David BreedQv_:; b' rr n a tv- r r nn r Willim
Irving [william.irvrng@n ranjj; Eric Neff (Grit oeffCia s com1; nantahala(anoc coin;
markLviamencana�h1tewater, pro; Kevin Colburn
Cc: Dunn. Lynne; 5iudrt. AID; Leatherman, Lisa A
Subject: RE: 7/23/19 Nantahala Failed Start
Date: Friday, July 26, 2019 5:05:11 PM
Good afternoon,
Good news, a defective piece of equipment in the switchyard has been found and work to replace It
is in progress. The newly installed equipment will be tested and if no issues are found following the
test, the Nantahala generator will return to service and be operable tomorrow morning. If test
indicates continued issues, Saturday, July 27, 2019 recreation flow will be provide from spillway gate
starting at 0500.
I will provide a definitive update later today to Nantahala generator's return to service
Sincerely,
Lisa
From: Leatherman, Lisa A
Sent: Thursday, July 25, 2019 5:10 PM
To: Juliet Jacobsen Kastorff<[e-mail]>; Bobbye Miller
<rafting@ rol lingthunderriverco.com>; Cathy Kennedy <cathy.ken [e-mail] Chris Lakey
<[e-mail]>; Jack Wise <[e-mail]>; Jeff Carter <[e-mail]>;
John Griffin <[e-mail]>; Ken Kastorff <[e-mail]>; Melanie McCullough
<[e-mail]>; Sue Matz <[e-mail]>;
[e-mail]; [e-mail]; [e-mail]; Mark Thomas - Paddle Inn
Rafting Company <[e-mail]>; [e-mail]; Jeremiah Haas
<[e-mail]>; Kay Tufts <[e-mail]>; [e-mail];
raft@caroll naoutfitters.com; [e-mail]; [e-mail];
[e-mail]; Eli Fowler <[e-mail]>; Daniel Hales
<[e-mail]>; Dewhurst, Nathan -FS <[e-mail]>; Wood, Joseph B -FS
<[e-mail]>; Saylors, Thomas C -FS <[e-mail]>; Yahoo
<[e-mail]>; Nicholas McCullough <[e-mail]>;
[e-mail]; Tanner Giesey <[e-mail]>; Bryan Tompkins
([e-mail]) <[e-mail]>; Fred Tarver ([e-mail])
<[e-mail]>; Barnett, Kevin ([e-mail])
<[e-mail]>; Goudreau, Chris<[e-mail]>; DeWeese Jr., Jerry
Lee <[e-mail]>; Tim Warren ([e-mail])
<[e-mail]>; brent martin ([e-mail])

<[e-mail]>; David Breedlove <[e-mail]>; Warren Cabe
([e-mail]) <[e-mail]>; William Irving ([e-mail])
<[e-mail]>; Eric Neff ([e-mail]) <[e-mail]>;
[e-mail]; [e-mail]; Kevin Colburn
<[e-mail]>
Cc: Dunn, Lynne <[e-mail]>; Stuart, Alan Witten <Alan.Stuart@duke-
energy.com>; Leatherman, Lisa A <[e-mail]>
Subject: RE: 7/23/19 Nantahala Failed Start
Good afternoon,
The spillway gate will be closed this evening, Thursday, July 25, 2019 and reopened Friday, July 26,
2019 at 0500 to provide recreation flows.
Inspection of the switchyard equipment continues. To explain at a very high level-, the crew has to
isolate sections of the switchyard to perform the inspections, it is detailed work, requiring de -
energizing sections to complete inspections.
As always, the general public and members of the rafting/outfitters community on the Nantahala
River are strongly encouraged to monitor the USGS Streamflow Gauge at Hewitt for the most
current flow information.
/nr /nvvr �juvr`?Sri �_,;r�_p );.a�3,0,, PARAme[er�r�l
Please remember that tributary flows from White Oak, Dicks Creek and other watersheds add flows
into the Nantahala River in addition to the regulated flow.
I will continue to provide updates on continued work at Nantahala Powerhouse and switchyard.
Thank you for your interest, patience and continued cooperation,
Lisa
From: Leatherman, Lisa A
Sent: Wednesday, July 24, 2019 3:55 PM
To: Juliet Jacobsen Kastorff <i ray - - :iv e(1(ures.con >; Bobbye Miller
<r�[1nPCNr.QIhnPlhunderr •, + >; Cathy Kennedy <�---1- 1,-- �Unoc.r�-)m>; Chris Lakey
<thris.l;akar,,anoc.cc)m>; Jack Wise < >; Jeff Carter <, ffPr k rr�-ukcam .com>;
John Griffin <aponversPaol.ce >; Ken Kastorff <-1rrvadv,cei cs corn>; Melanie McCullough
<mJ11OLfl r1iingth in--fernverr_o.ct >; Sue Matz < s-. frr rn3'L m>;
hQlingchev 8.@aol Com; - f f r om ll. m; �., sk+retreatr.rom; Mark Thomas -Paddle Inn
Rafting Company <inf adleinnr�fti .� m>; ihaas(@wr_u.edu; Jeremiah Haas
<�haas[�em,arl.wc . 1i>; Kay Tufts <ki uF @f ,maiil.wcu.e u>; rnomita!uaddleinnraf rng cQm;
r f cQ.1m fi t r . m; rafting(@white-water crm; r-einarivPr-r n a)m il.cipm;
vl II r I rn hrr-rriv-r ; m; Eli Fowler <eli.fowler(@noc.com>; Daniel Hales
<�i�hales5i90�gi��ail.r _m>; Dewhurst, Nathan -FS <n w r't(a�f .f �i. >; Wood, Joseph B -FS
.fP-!. ,,>; Saylors, Thomas C-FS <tsaylors(@fs.fed.us>; Yahoo
<rnbertwa;dvl,o.nvah:,a c _,,n>; Nicholas McCullough <wiccllough. (w-—n�il_cs�rrv;

A It n e- guI k - .-; Tanner Giesey <taiir)er giesey�@ntac.corii>; Bryan Tompkins
(bryaneton1okina Nfwsgnv) <��ryan„[umpkiu@fw5.2>; Fred Tarver (fr - i rvarr@n am r? v)
<L!e .r rvPru)n r v>; Barnett, Kevin (kevin barnetrCa) nr.g�)
<kevrn.barn=LCcbn; fanr e: >; Gaudreau, Chris <chr� ,iu�;rea_rLa�n,_wrldlifDeWeese Jr., Jerry
Lee < srr We - a)rf ke-energy m>; Tim Warren ( t ri:h k c)hnrrn. )
<btworkhike. Rvh - aI_cm>; brent martin (,itarK��axoer�itlons �gmail.com)
«larkayx;;ediuun; faL m il.c , >; David Breedlove <dYLrrf PswalricQQn+ynr_.guv>; Warren Cabe
nL orZ>; William Irving (will 4,m.rrvirrg�an; ac-cum)
<wrllia -L---LTLnDnrc.com>; Eric Neff (-, ic n ffOc noc.com) <enc.neff(arnoc on
n-antahalaC-nr)c.com
Cc: Dunn, Lynne <��nne.Cr inn a cif •en r .ccn»; Stuart, Alan Witten <dlan Swart( duke-
erier y.com>; Leatherman, Lisa A <Liaa-e.aiiierrnan;cr,ikp onere,.c,,m>
Subject: RE: 7/23/19 Nantahala Failed Start
Good afternoon,
The spillway gate will remain open discharging - 500 cfs until Thursday evening for lake level
management and to provide recreation flows for July 25, 2019. Work continues on equipment in the
switchyard to resolve yesterday's failed start.
Please remember that tributary flows from White Oak, Dicks Creek and other watersheds add flows
into the Nantahala River in addition to the regulated flow.
As always, the general public and members of the rafting/outfitters community on the Nantahala
River are strongly encouraged to monitor the USGS Streamflow Gauge at Hewitt for the most
current flow information.
Duke Energy appreciates your continued patience and cooperation during this unplanned outage. I
will continue to provide updates.
Sincerely,
Lisa
From: Leatherman, Lisa A
Sent: Tuesday, July 23, 2019 5-02 PM
To: Juliet Jacobsen Kastorff <iuliptP ?n tC 125;nyeradventures.corn>; Bobbye Miller
<r;,fjin,ftroll irsgLhunsieltrverc oTc:>; Cathy Kennedy < sh-v;kpnnedy(@nor coni>; Chris Lakey
< hn-.lakc-an .r m>; Jack Wise <iwisef@nuvr x.r:. >; Jeff Carter <--ff[a�_r_ockL�rrokcam cr n>;
John Griffin <aonrwersrd�aoLcc :-,>; Ken Kastorff <endnvadvtScs.com>; Melanie McCullough
<n irnLrull()Lip h r@ roll i nh nder nverco.}om>; Sue Matz <sue.afrr(cDgmail.com>;
7,Qvy3-3-8yaoLcom; r I ff r U mall m; rl-ngsk r�;rea:t corn; Mark Thomas - Paddle Inn
Rafting Company ihaasPwcu.edu; Jeremiah Haas
<,a�,_;;�rl.wcr.edu>; Kay Tufts <ki[uf[s(�email�vcu.edu>; m rn� a: : I rnnr f , LCJR�;

raft car I n-aoutfitters.com; ralting(@whrte-water.c1); ro in2rrvPr>rr;n(oi m
v! I� Ior0)J-.J �,r•derriver - ,. rt ; Eli Fowler <=Ji fC,,vI(-I m>; Daniel Hales
<_d�La c. cI nc �,�r r�rn3il.corn>; Dewhurst, Nathan -FS <ndewllurstrlfs.fecl.u5>; Wood, Joseph B -FS
Saylors, Thomas C -FS <tsavlors(wfs.fed.us>; Yahoo
<rohertA.Qi I,IGfa)y hr,- cLLrn>; Nicholas McCullough <nrn i!I- h @din rl.= m>;
wJdLrugtt(,D out look.com; Tanner Giesey < Wnn� csev,�ilt,oc.cr,rn>; Bryan Tompkins
(hryan tonrpkins(@fws Fes) <hrvan onipkrns(@fws.cov>; Fred Tarver (fr rver a ncdenr.gov)
<fP�+.�a_vPr� n�,denrv>; Barnett, Kevin (ki�yin,.h-.r)
<irE_v_iniarnQL(f@nr nr.eQ >; Goudreau, Chris <chr�s.Qotr drr ;an�wri_dlrfe.o >; DeWeese Jr., Jerry
Lee < err,,,.DP ,Ffd�duk. r, >; Tim Warren ( tworkhhi;k [e-mail])
<btworkhikes(c-uh_olina;l.cc, >; brent martin (aiarkaexped;tionsnagn) ri. rTr)
< I r i.n - �I�t�r�n,ra� David Breedlove <rl v; : (�Jswa.ncour,tvnc.gov>; Warren Cabe
(wcah �L [�rn rnrnc orr;) <wrifj = n� m r.:lnrs ->; William Irving (willi� m.;rving(a r1m)
<wrll;am.irvmU noc.corn>; Eric Neff (enc.neffra noc.rom) <-n .n f _[arnQ t m>;
nantaha3lRL noc.com
Cc: Dunn, Lynne <Lynne.Dun(uduke-energy oni>; Stuart, Alan Witten <Alan Starr (@duk
enemy -corn>; Leatherman, Lisa A <visa. Lea therrnanftQtj!Qrnergy.co T1>
Subject: RE: 7/23/19 Nantahala Failed Start
Good afternoon,
Investigation work continues to determine what caused the failed start of the Nantahala generator
this morning. The positive news is, the generating unit itself is fine, the issue lies between the
generator and outside equipment in the switchyard.
Given that it is not known if the problem will be found and resolved today, Duke Energy will open a
spillway gate at Nantahala Dam to release 500 cfs starting at 0500, Wednesday, July 24, 2019- The
spillway flow will reach the Nantahala Powerhouse and access areas by 0900. The spillway gate will
remain open until 1500 or later to accommodate recreation flow. Please remember that tributary
flows from White Oak, Dicks Creek and other watersheds add flows into the Nantahala River in
addition to the regulated flow.
As always, the general public and members of the rafting/outfitters community on the Nantahala
River are strongly encouraged to monitor the USGS Streamflow Gauge at Hewitt for the most
current flow information.
http:/Lw,trrrita u5 ov/nc/nwrs \,1?: r-'�'==C}i� -55 &PARAmzer cd=00065 00060
Duke Energy appreciates your patience and cooperation during this unplanned outage. I will
continue to provide updates.
Sincerely,
Lisa
From: Leatherman, Lisa A

Sent: Tuesday, July 23, 2019 10:34 AM
To: Juliet Jacobsen Kastorff < sit IveraCJv�nture .c�n�>; Bobbye Miller
<raftineProllingthundernverco com>; Cathy Kennedy <cathy.kennedy(@noc.corn>; Chris Lakey
< b)n-jc.cu n>; Jack Wise <iwit,e[&,nuvQx.n.-i>; Jeff Carter <1aff r rkr)rQ ,- iiT rp >;
John Griffin < .;.;�riyerss rani arm>; Ken Kastorff <_n Jrivgdv�L�.corr>; Melanie McCullough
<:,, ;,ii . an cz)r }Ilrn i h in'+Ari-iv rco.coni>; Sue Matz <sue.afrr(ragmaii.c(, >;
QI.CUrn; tole i - gmai! com; danOskiretreata Mark Thomas - Paddle Inn
Rafting Company <infQ(a7 arileinnro,ftiilg.rom>; 0aas(@wcu.edu; Jeremiah Haas
<iha.asPema+l.w ii.ed ,>; Kay Tufts <kitufts(�emaa.wcu.edu>; i. r•_L,
r f Pcarolinaoytfitter;.com; ra 'in whit?- : f eta--- i; r.i-ani; ragingriversr n w rn + l.r r m;
vlal; a r2 liina ii index rivar'_o.cnni; Eli Fowler <eli fowleriSnQc con»; Daniel Hales
< lesr,-19r}[c7i gma l-cam>; Dewhurst, Nathan -FS <ndewhurst(@f fed.us>; Wood. Joseph B -FS
< ,ter •h v. ci... >; Saylors, Thomas C -FS <tsavlors(@fs.fed.us>; Yahoo
<rQbertworrJNicholas McCullough <nmcculloughsOcgmail.com>;
w'iltrr, tt(-c,)outlook.com; Tanner Giesey <<� nner.eie �„�} �[++s:.m>; Bryan Tompkins
(brvanctomr)kinsnfws.gov) <bryan�tornnkins a fw rv>; Fred Tarver (fr rvar(JncdPnr.gQv)
<Fred.tarver(@ncdPnr eov>; Barnett, Kevin (kevin.bar netLLncd nr.>3 w)
<kevifi,barnetL(@ncdenr gynv>; Goudreau, Chris <chris.goudreauZi)n w-I_ iif _Qfg>; DeWeese Jr-, Jerry
Lee <,rerr t�Wa�-n»; Tim Warren (blwurkl-4-es_t?3hoLmail )
<jtwork�ii�e a(lhatrnail,s >; brent martin(alarkaexraec'rtions(cilgn-iail.com)
<alarkae -" li jons(�gmail.cQni>; David Breedlove <cl i- a) w inr , n n= - y>; Warren Cabe
(wc-abenrnacorinc. r) <wcabe(@rnac nn r-g>; William Irving (will'anr.irving(@rQc.corn)
<william.irvingOnor.cor i>; Eric Neff (enc.neff(Lior.com)
iiantaliala(@noc.com
Cc: Dunn, Lynne <LNy n- jkt,-r:nercv.c!Zm>; Leatherman, Lisa A <Lisa.lu_th-QrMaa(@duke
ena gy.corn>; Stuart, Alan Witten < rtn
Subject: RE: 7/23/19 Nantahala Failed Start
Good morning,
Cause of failed start identified and requires technicians outside of hydro generation to investigate
additional equipment, this team of technicians is based in Franklin and are in route to Nantahala
Plant. Return to service unknown at this time.
I will continue to provide updates.
Thank you,
Lisa
From: Leatherman, Lisa A
Sent: Tuesday, July 23, 2019 9:06 AM
To: Juliet Jacobsen Kastorff <;Qlie _ 0)F ndlessrivera& nth;. >; Bobbye Miller
<r f ,n air Ilia n rnv r m>; Cathy Kennedy <r a .kQr etyCo-inoc,�4n >; Chris Lakey
<cnris.Eaknyra�.nDy;_c;orn>; Jack Wise <iwise2nuv-Qx nr r.>; Jeff Carter <jPffPraQki ioOkc:ai1iQ. cjw>;
John Griffin <aR nv r (@aol com>; Ken Kastorff < i:adnvadv,,a cs corn>; Melanie McCullough

<mm cullg hrrcrl�in2`h inc rYrr v r rim>; Sue Matz <St,e.afcR (a�ail rciri>;
!rn2chevy3°${a .rZl �r�rn; r IF off=r 7a ain I, m; �+an�k�relrt a r_or:; Mark Thomas -Paddle Inn
Rafting Company <inf a-)paddleinnraftine.com>; fi iaas(@wcu.edu; Jeremiah Haas
<ii'vWed i?II, 1= i.� (i >; Kay Tufts <kitufts(u1)email.w r. du>; momlft3j i innrafting.corn;
- -v L PL'-` it:- SQL,
w_
' r • rdgingr iversr i gmail corn;
�Ifo(�rplljri�i n �r;+ver•,r,,; Eli Fowler<[e-mail]>; Daniel Hales
<r1_ ahall sU •(@gmarl.conv; Dewhurst, Nathan -FS <ndewhurstCufs.fed us>; Wood, Joseph B -FS
<iosechbwood(�fs.fed.us>; Saylors, Thomas C -FS <tsavlorsQFs.fe . , >; Yahoo
<rQf�rw of I cif - m>; Nicholas McCullough <nmrr- rlloh- (CUP[ 71-1 v;
wilt r r tt(cDoutfook.com; Tanner Giesey < nna�roiie- rla ncr.;cocn>; Bryan Tompkins
(i)ryar1 tom kins(@`ws.e44) <laryan torn pkins(@fws.gov>; Fred Tarver (fr i.-rverrr�ncdenr.ew)
<fred.tar-ver(�nco v->; Barnett, Kevin (kevin Barnett caP nr. v) ,
<k vin Barnet ��n_ri nr. v>; Goudreau, Chris <-nn .gouclreau na DeWeese Jr., Jerry
Lee < p-rr •. eWecseCcDd , enerP}y_ m>; Tim Warren(' W-rkh'kas(a)hotrr,aif.r_om)
<btworkhrkes; t Iic�,tmaiL.corn>; brent martin(alarkaexnedihonsPgmai1.corr,)
..larkaf-xhgsirtronsra;mail.com>; David Breedlove < avid b(@s,rjaincountvnc PQy>; Warren Cabe
(rvtaLie�rmae;;ni,r .•irk) <wcabe(-Omaconnc.orp; William Irving (will;am.irvi g(a7nc� .r r �)
<wilfi m,lrv�n _(a�nc-c.c�rr>; Eric Neff (eric.neff(rvnoc.corn) < ri- neff(l)noc.ci)m>;
nantahala()noc.com
Cc: Leatherman, Lisa A <Lisa.Lea herrr:an� du cP-energy.com>; Dunn, Lynne <Lynne.Qunn(u)duke-
Subject: 7/23/19 Nantahala Failed Start
Good morning all,
The Nantahala generating unit failed to start this morning. The cause for the failed start is unknown
at this time, technicians are in route to the powerhouse to investigate.
I will provide an update as information is received.
Thank you,
Lisa
Lisa Leatherman
Local Government and Community Relations Manager
Cherokee, Clay, Graham, Jackson, Macon and Swain Counties
w: 828.369.4534 1 c: 828.421,4534

Appendix B

APPENDIX B: Monitorina Data
Figure 1. Continuous temperature and DO measurements recorded in the Nantahala Bypassed Reach at
Nantahala Dam Rd. Due to the shorter spillway gate release on July 28, the logger recorded data for one
hour and are not presented, although measurements were similar to the two previous days during this
time.
Dissolved Oxygen and Temperature at Nantahala Dam Dr. (7/26/19)
+F Cont—s00 A Hydmlab DDSWCheck — Ccrtou—Temptnyht ms A HWmbb Temo5oot Ched(n`hta.rl
ip
28
26
24
8
22
m
E
❑
V
20
7
0
e
a
u
a
18 E
o
`
6
16
14
5
12
4
10
8 24
9:07 5:50 10.33 I1:16 1200 12:43 13 26 14:09 14.52
15:36
Time
Dissolved Oxygen and Temperature at Nantahala Dam Dr. (7/27/19)
—0-Cmhnuotn
DO A Hydroiab DO Spot Check — Ccritrimus Temp (right am 6 Hydrotab Temp Spot Check (right
am%
10
28
76
a
24
s
❑ ° e
22
E
u
a
20
7
0
o
o
18 a
0 6
16
IA
5
12
4
10
7 12
7.55 8 38 9 21 1004 1048 11:31 12-14 12:57 1340 14.24 15:07
Time

Table 1. Discrete temperature and DO measurements in the Nantahala Bypassed Reach and other
strategic locations downstream of the Bvoassed Reach.
Hydrolab Discrete Measurements
Site
Date
Time
Temp
DO
DO
Notes
Nantahala Dam Dr.
7/26/2019
9:12
24.5
7.53
92.5
12:33
24.9
7.56
93.7
15:00
25.3
7.47
93.0
7/27/2019
7:57
24.3
8.03
98.4
10:34
24.6
8.12
99.6
14:06
25.3
8.08
100.6
7/28/2019
10:27
24.8
7.50
96.5
15:15
24.6
6.71
86.0
Upstream Whiteoak
7/26/2019
9:45
22.3
8.01
94.0
13:00
23.8
7.87
95.2
15:58
24.5
7.77
95.2
7/27/2019
8:20
19.4
9.10
101.2
10:57
23.2
8.46
101.4
14:31
24.9
8.25
102.5
7/28/2019
10:50
23.5
7.85
99.0
12:14
24.2
7.74
98.8
16:15
25.0
7.41
95.8
Wishon's
7/26/2019
10:21
19.5
8.55
95.1
13:20
22.8
7.98
95.0
16:15
23.7
7.85
94.8
7/27/2019
7.29
17.5
9.25
98.6
Pre-Rec Flows
8:37
17.0
9.53
100.7
Pre-Rec Flows
11:11
21.7
8.71
101.4
14:45
24.1
8.37
102.0
7/28/2019
7:59
18.0
8.63
97.4
Pre-Rec Flows
11:05
22.2 j
8.08
99.1
17:36
23.7 1
7.79
98.4
NOC
7/26/2019
16:36
23.4
7.86
94.4
7/28/2019
13:37
19.7
8.82
103.0
18:20
24.1
7.71
97.9
Queens Creek
7/28/2019
11:31
21.4
8.00
96.2
White Oak Creek
7/28/2019
12:02
16.9 j
8.91
78.0
Pre-Rec Flows
16:15
18.0
8.56
96.5
Pre-Rec Flows
Nantahala Power Canal
7/28/2019
17:50
10.9
7.43
71.2
Hydro Operational
Rafting Put -in Loc 1
7/28/2019
17:53
10.9
7.65
73.7
Hydro Operational

Table 2. Hourly temperature measurements recorded at the spillway gate sill from 7/23 - 7/29.
Date Time
Temp ('C)
Date Time
Temp ('C)
Date Time
Temp ('C)
Date Time
Temp ('C)
7/23/19 000
26.3
7/25/19 0:00
24.7
7/27/19 0.00
25.2
7/29/19 0:00
25.3
7/23/19100
26.3
7/25/191:00
24.7
7/271191:00
252
7/29/191:00
25.3
7/23/19 2:00
26.2
7/25/19 2:00
24.7
7/27/19 2:00
25.2
7/29/19 2:00
25.3
7/23/19 3:00
26.1
7/25/19 3:00
24.8
7127/19 3:00
25.1
7/29/19 3:00
25.3
7/23/19 4:00
26.1
7/25/19 4:00
24.8
7127/19 4:00
25.1
7/29/19 4:00
25.3
7/23/19 5:00
26.1
7/25/19 5:00
24.9
7/27/19 5:00
25.1
7/29/19 5:00
25.3
7/23/19 6:00
26.1
7/25/19 6:00
24.9
7/27/19 6:00
25.1
7/29/19 6:00
25.3
7/23/19 7:00
26.0
7/25/19 7:00
25.0
7127/19 TOO
25.1
7/29/19 7:00
25.3
7/23/19 8:00
26.0
7/25/19 8:00
25.0
7/27/19 8 00
25.1
7/29/19 8:00
25.3
7/23/19 9:00
26.0
7/25/19 9:00
25.0
7/27/19 9 00
25.1
7/29/19 9:00
25.3
7/23/1910:00
26.0
7/25/1910:00
25.1
7/27/1910:00
25.2
7/29/1910:00
25.3
7/23/1911:00
26.0
7/25/1911:00
25.1
7/27/1911:00
25.2
7/29/1911:00
25.3
7/23/1912:00
26.0
7/25/1912.00
25.2
7/27/1912:00
252
7/29/1912:00
25.3
7/23/19 13:00
26.0
7/25/19 13:00
25.2
7/27/19 13:00
252
7/29/19 13:00
25.3
7/23/19 14:00
26.0
7/25/19 14:00
25.2
7/27/19 14:00
252
7/29/19 14:00
25.3
7/23/19 15:00
25.8
7/25/19 15:00
25.3
7/27/19 15:00
25.2
7/29/19 15:00
25.3
7/23/19 16:00
25.6
7/25/19 16:00
25.3
7/27/19 16:00
25.2
7/29/19 16:00
25.3
7/23/19 17:00
25.4
7/25/19 17:00
25.2
7/27/19 17:00
25.2
7/29/19 17:00
25.3
7/23/19 18:00
25.3
7/25/19 18:OD
25.2
7/27/19 18:00
25.3
7/29/19 18:00
25.3
7/23/19 19:00
25.1
7/25/19 19:OD
25.2
7/27/19 19:00
25.3
7/29/19 19:00
25.3
7/23/19 20:00
24.9
7/25/19 20:00
25.2
7/27/19 20:00
25.3
7/29/19 20:00
25.3
7/23/19 21.00
24.9
7/25/19 21:00
25.2
7/27/19 21:00
25.3
7/29/19 21:00
25.2
7/23/19 22 00
25.0
7/25/19 22:00
25.1
7/27/19 22:00
253
7129119 22:00
252
7/23/19 2300
25.3
7/25/19 23:00
25.1
7/27/19 23:00
25.4
7/29/19 23:00
25.2
7/24/19 0 00
25.3
7/26/19 0:00
25.1
7128/19 0:00
25.3
7/24/19 1-00
25.2
7/26/191:00
25.1
7/28/191:00
252
7/24/19 2 00
25.0
7/26/19 2:00
252
7/28/19 2:00
25.2
7/24/19 3-00
24.9
7/26/19 3:00
252
7/28/19 3:00
25.1
7/24/19 4 00
24.7
7/26/19 4:00
25.2
7128/19 4:00
25.1
7/24/19 5 00
25.0
7/26/19 5:00
25.2
7/28/19 5:00
25.0
7/24/19 6 00
24.4
7/26/19 6:00
25.2
7/28/19 6:00
24.9
7/24/19 7 00
24.5
7/26/19 7:00
252
7/28/19 7:00
249
7/24/19 8,00
24.6
7/26/19 8:00
25.2
7/28/19 8:00
24.9
7/24/19 9:00
24.8
7/26/19 9:00
252
7/28/19 9:00
250
7/24/19 10,00
25.0
7/26/1910:00
25.2
7/28/1910:00
25.0
7/24/1911.00
25.1
7/26/1911:00
25.2
7/28/1911:00
25.1
7/24/1912 00
25.0
7/26/1912:00
25.2
7/2811912:00
25..2
7/24/19 13:00
24.8
7126/1913:00
252
7/28/1913:00
25.2
7/24/19 14:00
24.6
7/26/19 14:00
252
7/2811914:00
25.3
7/24/19 15:00
24.5
7/26/19 15:00
252
7/28/19 15:00
25.3
7/24/19 16:00
24.5
7/2611916:00
25.2
7/28/19 16:00
25.3
7/24/19 17:00
24.5
7/26/1917:0D
25.2
7/28/19 17:00
25.3
7/24/19 18:00
24.5
7/26/19 18:00
25.2
7/28/19 18:00
25.3
7/24/19 19:00
24.6
7/26/19 19:00
25.2
7/28/19 19:00
25.3
7/24/19 20:00
24.6
7/26/19 20:00
25.2
7/28/19 20:00
25.3
7/24/19 21:00
24.6
7/26/19 21:00
252
7/28/19 21:00
25.3
7/24/19 22:00
24.6
7/26/19 22:00
252
7/28/19 22:00
25.3
7/24/19 23:00 1
24.6
7/26/19 23:00 1
252
7/28/19 23:00 1
25.3