HomeMy WebLinkAbout20030181 Ver 7_More Info Received_20100528 (2)k Duke
fWEnergy®
Carolinas
May 26, 2010
Mr. John Dorney
North Carolina Division of Water Quality
2321 Crabtree Boulevard, Suite 250
Raleigh, NC 27604
HYDRO LICENSING AND LAKE SERVICES
Duke Energy Carolinas, LLC
526 South Church St.
Charlotte, NC 28202
Mailing Address:
EC12K / PO Box 1006
Charlotte, NC 28201-1006
Re: Submittal of Section 401 Water Quality Certification Application Addendum No. 1
Mission Hydroelectric Project, FERC Project No. 2619
DWQ S@- U3 - 0 ? 8 ? U -1
Clay and Cherokee Counties, North Carolina
Dear Mr. Dorney:
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MAY ? ZCit?
DEN¢R- WER OJAUTY
WETLANDS AND ST ;;sir;!ER BRANCH
On June 16, 2009, Duke Energy Carolinas, LLC (Duke) withdrew the previous Mission Project 401
Water Quality Certification (401 WQC) Application and simultaneously submitted a new 401 WQC
Application to the North Carolina Division of Water Quality (NCDWQ). The one-year timeframe that the
Federal Energy Regulatory Commission (FERC) allows states to process 401 WQC applications for
relicensing of hydro projects expires on June 16, 2010 (i.e., one year following the date that Duke's 401
WQC Application was stamped accepted by NCDWQ) for the Mission Project.
As you are aware, Duke has been engaged in consultation with the United States Fish & Wildlife Service
(USFWS), NCDWQ, North Carolina Division of Water Resources (NCDWR) and the North Carolina
Wildlife Resources Commission (NCWRC) to prepare a Lake Level and Flow Management Plan, a
Maintenance and Emergency Protocol and a Sediment Management Plan to help further define how the
hydro project could operate under a New License from the FERC. This consultation has been productive
and Duke is very grateful for the time commitment provided by these agencies over the past several
weeks.
Attached to this letter you will find the Mission Project Lake Level and Flow Management Plan along
with the Nantahala Area Run-of-River Hydro Projects Maintenance and Emergency Protocol (as an
Appendix to the Mission Project Lake Level and Flow Management Plan). Duke has incorporated the
results of the agency consultation into the attached documents and we are hereby submitting them as
Addendum No. 1 to Duke's Mission Project 401 WQC Application.
By separate cover, Duke will also file a proposed Sediment Study Plan as Addendum No. 2 for the
Mission Project 401 WQC Application.
www.duke-energy.com
If there are any questions please call Steve Johnson at 704-382-4240.
Sincerely,
' ??' T)' ?e4
Steven D. Jester, Vice President
Hydro Strategy, Licensing and Lake Services
Duke Energy Carolinas, LLC
cc: Mr. Kevin Barnett, Asheville NCDWQ Regional office
Mr. Jim Mead, NCDWR
Mr. Chris Goudreau, NCWRC
Mr. Mark Cantrell, USFWS-Asheville
Secretary, FERC
Steve Johnson, Duke
Jeff Lineberger, Duke
Phil Fragapane, Duke
Attachment
Duke Energy Carolinas, LLC
Mission Project (P-2619)
Lake Level and Flow Management Plan
May 26, 2010
Background
The Mission Project (FERC # 2619) (the Project) is located on the Hiwassee River approximately 9 miles
downstream of the City of Hayesville, North Carolina, in Clay County and approximately 15 miles
downstream of the Tennessee Valley Authority's (TVA) Chatuge Dam, which regulates inflow into the
Mission Project. Mission Dam crosses the Hiwassee River at River Mile 106.1.
Constructed by the Town of Andrews, North Carolina to serve its citizens, the Project was considered
complete when the two original units were put on-line in December 1924. Nantahala Power and Light
Company (NP&L) purchased the Project from the Town 5 years later and installed a third unit in 1943 to
better utilize available flow in the river. The Project was licensed by the Federal Energy Regulatory
Commission (FERC) on August 4, 1980. Duke Power (now Duke Energy Carolinas, LLC) (Duke)
acquired NP&L in 1988. Duke's Hydro Central assumed operational control of NP&L's hydro stations in
August 2000.
The Mission Project consists of a reservoir, dam, and powerhouse plus a small amount of land
surrounding the dam, tailrace and reservoir. Mission Dam was originally designed as an Ambursen-type,
flat slab concrete structure. In 1999, due to continuing concrete deterioration, slab areas in Bay Nos. 1, 2,
3, 4, 8, 9, 10, 11, 19, 20, and 21 were filled, essentially changing the dam to a concrete gravity type
structure. The electricity from the generators is regulated by one transformer located adjacent to the
powerhouse. Duke owns approximately 102 acres within and adjacent to the Project and the Mission
Reservoir has approximately 3 miles of shoreline.
Major components of the Mission Dam (also referred to herein as the Project Dam) are listed below,
beginning at the left abutment (facing downstream). Unless stated otherwise, all elevations are referenced
in U.S. Geological Survey (USGS) datum and are expressed in feet above mean sea level (AMSL).
• Three bulkhead sections with crest elevation 1665.17 ft AMSL.
• Seven ogee spillway sections surmounted by 14-foot-high, 16-foot-wide gates with the top of the
gates at Elevation 1658.17 ft AMSL (i.e. the Normal Full Pond Elevation) and an opening deck at
Elevation 1665.17 ft AMSL.
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• Four bulkhead sections with crest elevation 1665.17 ft AMSL.
• A powerhouse intake structure with crest elevation 1665.17 ft AMSL.
• Four bulkhead sections with crest elevation 1665.17 ft AMSL.
The buttresses for each bulkhead and spillway bay are spaced 18 feet on-center. Including the
powerhouse intake structure and a 12-foot long access section at each abutment, the dam has a total crest
length of 397 feet and a maximum height of 50 feet. Three of the seven Tainter gates are operated
automatically by an independent control center located in a metal building on the deck above the gates.
Gate No. 7, located nearest the left abutment, opens automatically when the reservoir reaches Normal Full
Pond Elevation (Elevation 1,658.17 ft AMSL). Gate No. 5 raises automatically after Gate No. 7,
followed in turn by Gate No. 6. The remaining gates are operated manually by a movable hoist on rails
on the deck above the spillway.
The powerhouse is separate from the dam and consists of a reinforced concrete substructure and a brick
superstructure of conventional architecture of the period in which the Project was built. Inside the
powerhouse are three generating units. Each one consists of an S. Morgan Smith vertical Francis-type
turbine directly connected to a 750-kilovolt-ampere (kVa) General Electric generator at 0.80 power factor
and a DC exciter. The turbines of Unit Nos. 1 and 2 (left and center bays facing downstream), installed in
1924, are each rated at 930 horsepower (hp) under 38-foot head and 225 revolutions per minute (rpm),
while the Unit No. 3 turbine is rated at 1,040 hp at 40-foot head and 225 rpm. Each unit has a 34.9 foot-
long, 8-foot diameter steel cased penstock. Unit Nos. 1 and 2 each have a steel cased draft tube and Unit
No. 3 has a concrete Al-5 cased draft tube.
Normally, the plant is capable of producing 2,200 kilowatts (kW) under an average net head of 41.2 feet.
The rated hydraulic capacities of the turbines are 216 cfs for Unit Nos. 1 and 2 and 247 cfs for Unit No. 3.
The maximum hydraulic capacities of Units 1 & 2 and Unit 3 are 247 cfs and 292 cfs respectively. The
minimum hydraulic capacities of Unit Nos. 1 & 2 and Unit 3 are 141 cfs and 165 cfs respectively. The
average annual generation for the Mission Project over the period of 1941 to 2002 was 8,134,370 kWh.
Total maximum hydraulic capacity of the 3 units combined at the Mission Project is 786 cfs.
The Mission reservoir has a surface area of approximately 47 acres at Normal Full Pond Elevation
1,658.17 ft AMSL. The drainage area upstream of the dam encompasses 292 square miles of which 189
square miles are impounded by the TVA Chatuge Dam. The drainage area is mountainous and extends
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into both western North Carolina and north Georgia. The average annual runoff into the Project reservoir
is 661 cfs.
There are three intakes at the Mission Project. Each intake system is an 8-foot diameter steel-cased
penstock with a 25 foot by 16 foot grated trash rack mounted at a sloping angle in front of the intake pipe.
The intake trash rack is located 20 feet 3 inches in front of the bottom of the penstock pipe. The steel
grating bars are 3/16-inch diameter thick and the center to center spacing between the bars varies from
2.25 inches to 2.5 inches. Horizontal support bars are spaced 3 feet apart. These bars are round and have
a diameter of 1.5 inches. Reservoir level is approximately 1 foot below the top of the grating during
periods of maximum generation. Under the current license for the Mission Project, Duke releases a
minimum flow of 280 cfs or inflow, whichever is lower.
Flows downstream of the Project reservoir have been measured in the past at the U.S. Geological Survey
(USGS) Gage Hiwassee River upstream of Murphy, NC (Gage #03548500) and can be found at the
USGS web site address: http://waterdata.usgs.gov/nc/nwis/uv?slte_no=03548500. This gage has been
inactive since September 2004.
Under the current license, the Mission Project operates in approximate run-of-river mode (ROR) with an
ordinary available drawdown of approximately 6 inches. Project generation is dependent upon the
availability of stream flow in the Hiwassee River, which is regulated by TVA's Chatuge Dam. The
Project operates semi-automatically; a float controls the wicket gates automatically, but the units must be
put on-line or taken off-line manually. The float makes the units responsive to headwater pool levels,
which are determined by variations in stream flow. Through a series of relays, the float controls the
governor and opens or closes the wicket gates as necessary to utilize available flow while typically
maintaining reservoir level within a band from approximately 6 inches below Full Pond Elevation to Full
Pond Elevation.
Unit No. 3, then No. 2, takes available stream flow up to a combined generator output of 1,500 kilowatts.
Unit No. 1 then takes any flows in excess of this capacity. When stream flow decreases, Unit No. I
reduces its load but maintains synchronous speed by motoring. If stream flow continues to decrease, Unit
2 and 3 will also change mode to synchronous speed motoring.
3
Duke submitted an application for New License for the Project on July 17, 2003. In this License
Application Duke proposed to operate the Project in a run-of-river (ROR) manner such that outflow from
the Project is approximately equal to inflow into it at any given time. In a subsequent Environmental
Assessment (EA) issued on July 12, 2006, the FERC recommended that in order to meet the intent of
ROR operations Duke should operate the Project so that Project reservoir levels are within 0.1 ft of full
pond for 99 percent of the time and within 0.3 ft of full pond the remaining 1 percent of the time on a
annual basis. In addition, the FERC recommended (i.e., Nantahala West Project Final Environmental
Assessment-July 12, 2006) that Duke consult with the appropriate resource agencies to develop a Lake
Level and Flow Management Plan (LLFMP) for the Project to ensure compliance with ROR operations,
as well as a Sediment Management Plan for the Project.
In 2004, Duke filed the initial Application for a Section 401 Water Quality Certification (401 WQC) with
the North Carolina Division of Water Quality (NCDWQ). Since that time, Duke has withdrawn and
resubmitted its application for a 401 WQC each year. The 401 WQC Application is currently under
review by the NCDWQ.
Purpose
The purpose of the Mission Project LUMP is to provide a framework for appropriate management and
monitoring of reservoir levels and flows downstream of the Project during normal operations, and
maintenance and emergency situations under the New License.
Objectives
The objectives of the LUMP are as follows:
1. Describe lake level and flow management during normal Project operations
2. Describe potential operational problems and solutions
3. Describe compliance monitoring and reporting procedures
4. Describe procedures for maintenance and emergency operations.
Normal Project Operations
The definition of ROR operations for a hydro project is that outflow is approximately equal to inflow at
any given point in time. This can be achieved by maintaining Project reservoir levels at a constant
elevation called the Normal Target Elevation. For this LUMP, Normal Target Elevation is defined as the
level of a ROR Project reservoir (measured in ft above Mean Sea Level (AMSL) or feet relative to the full
pond contour with 100.0 ft corresponding to full pond) that the Licensee will endeavor in good faith to
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achieve, unless operation in the Maintenance and Emergency Protocol allows otherwise. For this Mission
Project LUMP, Normal Target Elevation will be 99.5 ft. local datum which equates to Elevation
1,657.67 ft AMSL. In order to achieve a consistent reservoir level, control must be maintained through
operation of the Project's hydro units, Tainter gates, or both. The operating philosophy for normal
operations of Tainter gates and hydro units at the Project is described in the following:
Hydro Unit Operation
• A Programmable Logic Controller (PLC) will control each hydro unit.
• The operation of the hydro unit will be determined by lake level, electrical grid system conditions,
and amount of debris build up on trash racks.
• Lake levels will be managed to maintain the Normal Target Elevation (99.5 ft.), with 100.0 ft
representing the Normal Full Pond Elevation of 1,658.17 ft AMSL.
• The lake level set point for hydro unit control must be at a lower elevation than the lake level set
point for Tainter gate control such that the hydro units will operate prior to Tainter gate operation.
Tainter Gate Operation
• For the Tainter gates with automatic controls, PLCs compare actual lake level to a lake level set point.
• The PLC will control the Tainter gate position based on the lake level set point value.
• When reservoir levels continue to rise during hydro unit operation, the Tainter gates open as water
levels rise in order to maintain reservoir levels at Normal Target Elevation.
• A permanent back-up generator that will provide a redundant power source to the Project (i.e., Tainter
gates) during emergency situations (e.g., power loss) will be provided.
Based on the operations philosophy described above, the Project reservoir level control will consist of the
following components:
• A 5 psi pressure transducer secured in a stilling well and calibrated to measure lake level based on
Normal Full Pond Elevation of 100.0 ft local datum. The transducer is accurate to within 0.01 feet.
A back-up transducer is also installed.
• A gate position transducer with a stainless steel tape connected to the top of each automatically
controlled Tainter gate. The transducer measures gate opening from fully closed to fully open with an
accuracy of 0.02 feet.
• Each automatic gate hoist has an encoder on the shaft that gives a relative position of the Tainter gate
to the position of the hoist shaft.
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• Each hoist has a low limit and a high limit switch on the hoist shaft.
• A PLC is used to control Tainter gate movement through either a (1) variable frequency drive or (2)
motor contactors. Manual control is also available.
• There is a communication system between the Tainter gate controller and the plant controller. These
controllers communicate either by radio, fiber link, modem, or RS485.
• The Tainter gate PLC communicates the status of the gate position, lake level, and alarm points to the
plant PLC.
• The plant PLC communicates via wireless modem to the work station node at the Nantahala Hydro
Station (FERC Project 2692).
• The information from the Nantahala Hydro Station is sent to Hydro Central in Charlotte, North
Carolina through a secure network.
Potential Operational Issues:
There are a number of factors that can affect the Project reservoir level control. These factors include
equipment failures, high inflow conditions, and debris build up in front of trash racks and Tainter gates.
• A PLC response to rapid changes in these reservoir level factors may result in reservoir level
variations greater than 0.1 feet.
• Since the Tainter gates at the Mission Project are large (14 ft high x 16 ft wide), control of gate
position by the PLC to a tolerance of 0.02 feet allows for flow variances of 10 cfs or more through
each automatically controlled gate.
• There are occasional conditions, such as when there is trash or debris accumulations on the trash
racks which may create situations when one of the units cannot maintain the lake level set point. At
these times, an automated Tainter gate will begin pond control when the lake level is 0.05 feet above
the lake level set point for hydro unit operation.
Compliance Monitoring and Reporting
Run-of-River Compliance
Provided the Project is not operating in the Nantahala Area ROR Projects Maintenance and Emergency
Protocol (see Appendix), the Mission Project will be considered in compliance with ROR operations
under the following conditions:
• Reservoir elevations maintained at f0.3 ft of Normal Target Elevation (99.5 ft.) when less than 2
hydro units are operable
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• Reservoir elevations maintained t0.1 ft of Normal Target Elevation (99.5 ft.) for 99% of year and
f0.3 ft of Normal Target Elevation (99.5 ft.) for I% of year when 2 or more hydro units are operable
• If the Licensee determines that the Project will have less than 2 hydro units operable for a period of
more than 60 consecutive days, the Licensee will consult with the agencies identified in the MEP
within 30 days of making such a determination, to develop a plan and schedule for complying with
ROR operations.
Reporting
• Reservoir elevation data will be collected no less frequently than every 15 minutes. Real-time
reservoir elevation information will be available for the Project at URL http://www.duke-
energy.com/lakes/nantahala/nantahala-lake-levels.asp
• The Licensee will provide 7-day reservoir history on its website. Any other history or period of
record is available from the Licensee upon written request.
• The Licensee will archive the 15-minute reservoir elevation data for the term of the New License.
• No later than March 31 of each calendar year beginning the first full calendar year after the calendar
year in which the New License is issued, the Licensee will provide to the NCDWQ, NCDWR, the
NCWRC, and the USFWS and file with the FERC a report containing a table of the elevation of the
reservoir on a daily basis (including midnight, daily minimum and maximum elevations) during the
previous calendar year, a certification by the Licensee that the lake level requirements were met
during the previous calendar year, and a discussion of each incident during the previous calendar year
where the elevation of the reservoir was above or below the normally required levels.
• After five full calendar years of operation under the New License, the Licensee will confer with the
NCDWR, NCDWQ, NCWRC, USFWS, and the FERC to consider holding an informational meeting,
to review the operational history of the LUMP and to determine if any operational changes are
needed and agreeable to all the parties. Any such meeting will be scheduled and held no later than
October 31 of the appropriate year.
Emergency and Other Non-Routine Operations
• The Licensee will enhance remote monitoring of the Mission Project by implementing an
expanded alert system concerning gate control failures, hydro unit trips, power failures, low
inflows, and other situations where downstream flows could be temporarily interrupted.
• Alerts will be directed to the Licensee where appropriate technical staff will be called out as
needed to respond to such situations.
• In addition the Licensee will provide a key contact individual that will be available during normal
business hours for the agencies to contact should significant Project-related issues arise.
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APPENDIX
NANTAHALA AREA RUN-OF-RIVER PROJECTS MAINTENANCE AND EMERGENCY PROTOCOL (MEP)
Introduction
Under some emergency, equipment failure, maintenance or other abnormal situations, certain license
conditions may be impractical or even impossible to meet and may need to be suspended or modified
temporarily to avoid taking unnecessary risks. The objectives of this protocol are:
1) to define the most likely abnormal situations for the Nantahala Area Run of River (ROR)
Projects (i.e., Mission, Bryson and Franklin Projects),
2) describe the operations protocol for certain abnormal situations,
3) identify the potentially impacted license conditions,
4) outline the general approach that the Licensee will take to mitigate the impacts to license
conditions, and
5) describe how these situations will be communicated to resource agencies and others.
Note: Due to the potential variability of these abnormal situations, this Maintenance and Emergency
Protocol (MEP) is not intended to give an exact step-by-step solution path. It will, however, provide
basic expectations for the Licensee's approach to dealing with the situation. Specific details will vary
and will be determined on a case-by-case basis as the protocol is being enacted.
The Licensee will review the requirements of this protocol each time it is used and may revise the MEP
from time to time as noted below.
Key Facts and Definitions
1. Human Health and Safety and the Integrity of the Public Water Supply and Electric Systems are
of Utmost Importance - Nothing in this protocol will limit the Licensee's ability to take any and
all lawful actions necessary at the Project to protect human health and safety, protect its
equipment from major damage, and ensure the stability of the regional electric grid and public
water supply systems. It is recognized that the Licensee may take the steps that are necessary to
protect these things without prior consultation or notification. Likewise, nothing in this MEP will
limit the State of North Carolina from taking any and all lawful actions necessary in its
jurisdiction to protect human health and safety. It is recognized that North Carolina may also
take the steps necessary to protect these things without prior consultation or notification.
2. Normal Full Pond Elevation - Also referred to simply as "full pond," this is the level of a reservoir
that corresponds to the point at which water would first begin to spill from the reservoir's
dam(s) if the Licensee took no action. This level corresponds to the lowest point along the top
of the spillway (including flashboards) for reservoirs without floodgates and to the lowest point
along the top of the floodgates for reservoirs that have floodgates. To avoid confusion among
the many reservoirs the Licensee operates; it has adopted the practice of referring to the
Normal Full Pond Elevation for all of its reservoirs as equal to 100.0 ft. relative. The following
are the Normal Full Pond Elevations for the Nantahala Area ROR Projects expressed in terms of
USGS datum (ft above Mean Sea Level (AMSL)) rather than relative or local datum:
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• Franklin Project - 2,000.22 ft AMSL
• Bryson Project - 1,828.41 ft AMSL
• Mission Project - 1,658.17 ft AMSL
3. Normal Target Elevation - The level of a ROR Project reservoir (measured in ft above Mean Sea
Level (AMSL) or feet relative to the full pond contour with 100.0 ft corresponding to full pond)
that the Licensee will endeavor in good faith to achieve, unless operation in this MEP allows
otherwise. The Normal Target Elevation for the Franklin and Mission Projects is 99.5 ft and it is
99.95 ft local datum for the Bryson Project. These Normal Target Elevations correspond to the
following USGS elevations at each ROR Project:
• Franklin Project -1,999.72 ft AMSL
• Bryson Project - 1,828.36 ft AMSL
• Mission Project - 1,657.67 ft AMSL
4. Returning to Normal - Some of the abnormal situations noted in this MEP can impact the
Licensee's ability to operate the hydro project in the most efficient and safest manner for power
production. The Licensee will therefore endeavor in good faith to repair existing hydro project
equipment and facilities and return them to service within a reasonable period of time,
commensurate with the severity of the equipment / facility repair requirements and availability
of budgeted funding. If the Licensee determines that the Project will have less than 2 hydro
units operable for a period of more than 60 consecutive days, the Licensee will consult with the
agencies identified in this MEP, within 30 days of making such a determination, to develop a
plan and schedule for complying with ROR operations.
5. Incidental Maintenance -These are maintenance activities at Project works that are very brief in
nature or that require minimal if any deviation from normal license conditions. For the purposes
of this protocol, maintenance of Project works that does not require deviation from any license
conditions related to prescribed flow releases from Project structures that is less than 24 hours
in duration and will not require any excursions below the Minimum Flow (as identified in this
MEP) is considered Incidental Maintenance and, except for the notification steps identified in
the tables below for communication with resource agencies and affected parties for conditions
that impact prescribed flow releases, Incidental Maintenance is exempt from the requirements
of this protocol.
6. Notification - Typically includes informing or providing information concerning a Project activity
or situation (e.g., scheduled maintenance drawdown) to interested parties. Notification is an
important aspect of the communication protocol for the Projects and can be used under both
scheduled and emergency situations.
7. Consultation - Typically includes meetings and/or correspondence regarding agency
deliberation, decision, or guidance concerning a Project activity (e.g., review operational
changes, review plan modifications). Consultation is also an important aspect of the
communication protocol for the Projects.
8. Notification Guidance
a. Scheduled Maintenance that Affects License Conditions - Typically, scheduled maintenance
is planned months in advance. Once a likely maintenance schedule has been established,
9
the Licensee will endeavor to provide as much advance notice as possible to the affected
parties identified in this protocol.
b. Unscheduled Maintenance and Emergencies that Affect License Conditions - It is not
possible for the Licensee to assure any level of advance notice. For these situations, the
Licensee will endeavor to inform the affected parties identified in this protocol within some
reasonable amount of time after the situation has been identified.
9. Minimum Flow-The minimum flow releases from the Nantahala Area ROR Projects that may be
necessary to:
a. prevent long-term or irreversible damage to aquatic communities consistent with the
resource management goals and objectives for the affected stream reaches;
b. provide some basic level of water quality maintenance in the affected stream reaches.
For the purpose of this MEP, the Minimum Flow will be equal to the September median flow for
the given Project. The Minimum Flows for the Nantahala Area ROR Projects are as follows:
• Little Tennessee River at Franklin Dam is 309 cfs.
• Oconaluftee River at Bryson Dam is 204 cfs.
• Hiwassee River at the Mission Dam is 341 cfs.
10. Organizational abbreviations include the Eastern Band of Cherokee Indians (EBCI), United States
Fish and Wildlife Service (USFWS), Federal Energy Regulatory Commission (FERC), United States
Geological Survey (USGS), North Carolina Department of Environment and Natural Resources
(NCDENR), North Carolina Division of Water Resources (NCDWR), North Carolina Division of
Water Quality (NCDWQ), North Carolina State Historic Preservation Office (NCSHPO), North
Carolina Wildlife Resources Commission (NCWRC), Duke System Operating Center (SOC) and
Duke Transmission Control Center (TCC).
11. Voltage and Capacity Emergencies - The electric transmission system serving the Nantahala
Area is part of the Licensee's main transmission system. The Licensee's system is connected to
other large transmission systems located in the southeast. If the Licensee's system reliability is
at risk due to Voltage and Capacity Emergencies, the ability to provide secure and continuous
electric service to the Licensee's electric customers becomes compromised. The Licensee's
System Operating Center (SOC) and Transmission Control Center (TCC) continuously monitor the
electric transmission system. Therefore, for the purposes of this protocol, a Voltage or Capacity
Emergency will exist when declared by the Licensee's SOC or TCC.
12. Large Extended Drawdown - Any drawdown of a Nantahala Area ROR Project reservoir that will
expose substantial lakebed areas for an extended period of time that are not normally exposed
during the year. For the purposes of this ROR Project MEP document, a Large Extended
Drawdown is any drawdown that is expected to maintain a ROR Project's reservoir level greater
than 1.0 foot below the Normal Target Elevation for at least 30 consecutive days.
13. Revising the MEP - The Licensee will review the requirements of this MEP each time it is used
and will consult with the pertinent agencies if the Licensee determines that revisions are
warranted. The Licensee will file any revised MEP with the FERC, including filing a license
amendment request if the Licensee determines that the amendment is needed.
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Assumptions
Run-of-River Operation - The Subsequent or New Licenses for the Nantahala Area ROR Projects
are expected to require the Projects to be operated in such a manner that outflow is
approximately equal to inflow at any given time while allowing variations during maintenance,
emergencies, and equipment failures.
Guidance for Responding to Abnormal Situations
The table below identifies the most likely abnormal situations when this protocol will be enacted and
the license requirements that would most likely be impacted.
Potentially Impacted
Abnormal Situation License Requirements
Situation Situation Name Indications Run-of-River
Letter Operations
A Hydro Unit Maintenance Maintenance will require Yes
hydro unit shutdown.
Maintenance will require
B Maintenance of Floodgates interruption of scheduled Yes
releases from normal
locations (e.g., gates)
Condition A or B (i.e. dam
failure has occurred, is
imminent or a potentially
C Dam Safety Concerns hazardous situation exists) is Yes
declared per Emergency
Action Plan or other dam
safety concern is identified.
Voltage or capacity conditions
on the electric grid in the
Licensee's system or the
larger regional electric grid
Voltage or Capacity cause the Licensee's system
D reliability and safety to be at Yes
Emergency risk and a voltage or capacity
emergency is declared by
Licensee's System Operating
Center (SOC) or Transmission
Control Center (TCC).
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Reservoir Drawdown Below The reservoir level is below
Normal Target Elevation due
Normal Target Elevation by
E to maintenance, emergency
more than is allowable for Yes
or other reasons (not due to normal operation
low or high inflow)
Safe access to regulated river
River Access Special reaches requires interruption
Ye
F
Circumstances
of releases from normal s
locations
Communication with Resource Agencies and Affected Parties
General Notification
As soon as possible after the Licensee determines that the response to an abnormal situation will
potentially impact license conditions, the Licensee will add appropriate messages to its public
information Web site and/or its reservoir level toll-free phone system to inform the general public.
Specific consultation is discussed below for each identified abnormal situation.
Notification and Consultation
Notification and consultation requirements are specified for each abnormal situation. The Licensee will
consider options suggested by the identified agencies and organizations that could lessen the impact of
the abnormal situation on the environmental, cultural and human needs relative to the Project.
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Abnormal Situation A.1- Scheduled Hydro Unit Maintenance
Mitigating Actions
1. Scheduling -To the extent practical, the Licensee will avoid scheduling hydro unit maintenance that
would impact flow requirements for aquatic habitat or water quality unless it is likely that the
equipment condition will cause damage or unscheduled unit maintenance if repairs are delayed.
2. Drawing Down the Affected Reservoir -To minimize the impacts to its electric customers, the
Licensee may choose to draw down a reservoir using its hydro units to minimize spillage from the
dam during maintenance operations.
3. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with the
resource agencies to (a) monitor any potential aquatic species impacts in the affected stream
segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation A.1- Scheduled Hydro Unit Maintenance
Notification Consultation Comments
Provide notification, initiate consultation and provide
NCDENR agencies 30 days to comment on drawdown plan as soon as
FERC NCWRC approximate dates are determined (typically months in
USFWS advance).
Consult at least 10 days prior to beginning the hydro unit
outage or any reservoir drawdown if maintenance will affect
NCSHPO Historic Properties (NCSHPO) and include consultation with
EBCI the EBCI if the maintenance will result in a Large Extended
Drawdown.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels).
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its reservoir
level toll-free phone system to inform the general public.
13
Abnormal Situations A.2 - Unscheduled Hydro Unit Maintenance
Mitigating Actions
1. Drawing Down the Reservoir -To minimize the impacts to its electric customers, the Licensee may
choose to draw down a reservoir using its hydro units to minimize spillage from the dam during
maintenance operations.
2. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with the
resource agencies to (a) monitor any potential aquatic species impacts in the affected stream
segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation A.2 - Unscheduled Hydro Unit Maintenance
Notification Consultation Comments
If the maintenance will affect run-of-river operations,
FERC NCDENR perform notification as soon as possible after the
NCD
NC NCWRC unscheduled hydro unit outage begins, but no longer than 5
NCWRC RC
USFWS
days afterwards. Begin consultation within 10 days after the
USFWS unscheduled hydro unit outage begins.
Notify (within 5 days) and consult (within 10 days) after the
hydro unit outage or drawdown begins with NCSHPO if
NCSHPO NCSHPO maintenance will affect Historic Properties and include
EBCI EBCI consultation with EBCI if the maintenance will result in a
Large Extended Drawdown.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels).
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its reservoir
level toll-free phone system to inform the general public.
14
Abnormal Situation B.1- Scheduled Maintenance of the Normal Means of Providing Minimum Flows
Mitigating Actions
1. Scheduling - To the extent practical, the Licensee will avoid scheduling maintenance (e.g.,
floodgate maintenance requiring drawdown; hydro unit outage) that would impact the ability of
the Licensee to release flows for aquatic habitat or water quality unless it is likely that the
equipment condition will cause damage or an unscheduled maintenance situation if repairs are
delayed.
2. Drawing Down the Reservoir -To minimize the impacts to its electric customers, the Licensee
may choose to draw down a reservoir using its hydro units to minimize spillage from the dam
during maintenance operations.
3. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with
the resource agencies to (a) monitor any potential aquatic species impacts in the affected
stream segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation B.1- Scheduled Maintenance of the Normal Means of Providing Minimum
Flows
Notification Consultation Comments
Provide notification, initiate consultation and provide
NCDENR
FERC NCWRC agencies 30 days to comment on drawdown plan as soon as
USFWS approximate dates are determined (typically months in
advance).
Notify (within 5 days) and consult (within 10 days) after the
NCSHPO NCSHPO hydro unit outage or drawdown begins with NCSHPO if
EBCI EBCI maintenance will affect Historic Properties and include
consultation with EBCI if the maintenance will result in a
Large Extended Drawdown.
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and/or its
reservoir level toll-free phone system to inform the general
public.
15
Abnormal Situation 6.2 - Unscheduled Maintenance of the Normal Means of Providing Minimum
Flows
Mitigating Actions
1. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with
the resource agencies to (a) monitor any potential aquatic species impacts in the affected
stream segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation 6.2 - Unscheduled Maintenance of the Normal Means of Providing Minimum
Flows
Notification Consultation Comments
If the maintenance cannot avoid impacting run-of-river
FERC
NCDENR NCDENR operations, perform notification as soon as possible after the
NCWRC NCWRC unscheduled maintenance begins, but no longer than 5 days
USFWS USFWS afterwards. Begin consultation within 10 days after the
unscheduled maintenance begins.
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and/or its
reservoir level toll-free phone system to inform the general
public.
16
Abnormal Situation C - Dam Safety Emergency
Mitigating Actions
Safety Must Come First - If a Condition A or B is declared per the Licensee's Emergency
Action Plan, or other dam safety concerns arise, the Licensee may modify or suspend any
license conditions immediately and for as long as necessary to restore the dam to a safe
condition.
Communication with Resource Agencies and Affected Parties
Abnormal Situation C - Dam Safety Emergency
Notification Consultation Comments
Conducted strictly in accordance with the Licensee's
Emergency Action Plan. In cases where dam safety
During EAP Condition A or B or concerns arise that are not a Condition A or B per the
Other Dam Safety Concerns Licensee's Emergency Action Plan, consultation with
resource agencies and affected parties will occur as soon as
possible, after the dam safety concern arises.
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
Once Dam Safety Conditions Have license conditions, the Licensee will add appropriate
Stabilized messages to its public information Web site and/or its
reservoir level toll-free phone system to inform the general
public.
Access Area Closure The Licensee will conduct notification procedures for any
Notification temporary recreation facility/Access Area closures (e.g.,
closure due to extended low reservoir levels).
17
Abnormal Situation D - Voltage and Capacity Emergencies
Mitigating Actions
1. Suspension of the Normal Run-of-River Project Operation - If a voltage or capacity emergency
(as defined above) occurs, the Licensee may modify or suspend reservoir level operating
limitations immediately and for as long as necessary if doing so would allow additional hydro
station operation that is needed to restore the electric grid to a stable condition.
2. Conserving Water for Power Generation - If a voltage or capacity emergency (as defined above)
occurs and if it is expected to continue for an extended period of time (e.g. two weeks or more),
the Licensee may reduce minimum flows to the applicable Minimum Flow (as defined above).
During a Voltage or Capacity Emergency, the Licensee will not deviate from the normal license
conditions to conserve water for power generation strictly as a cost avoidance measure, but
only to assist in addressing the emergency.
munication with Resource Aeencies and Affected Parties
Abnormal Situation D - Voltage and Capacity Emergencies
Notification Consultation Comments
FERC Perform notification as soon as possible, but no longer than 5
NCDENR NCDENR days following the deviation from a license condition for
NCWRC NCWRC Voltage or Capacity Emergency reasons. Initiate consultation
USFWS USFWS as soon as possible.
Notify (within 5 days) and consult as soon as possible with
NCSHPO NCSHPO if a Voltage or Capacity Emergency will affect
NCSHPO EBCI Historic Properties and include consultation with EBCI if the
emergency will result in a Large Extended Drawdown.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels).
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its reservoir
level toll-free phone system to inform the general public.
18
Abnormal Situation E.1- Scheduled Reservoir Drawdown
Mitigating Actions
Scheduling - To the extent practical, the Licensee will avoid scheduling reservoir drawdowns that
would impact the ability of the Licensee to release the Minimum Flow for aquatic habitat and water
quality.
Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with the
resource agencies to (a) monitor any potential aquatic species impacts in the affected stream
segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation E.1- Scheduled Reservoir Drawdown
Notification Consultation Comments
Provide notification, initiate consultation and provide
NCDENR
FERC NCWRC agencies 30 days to comment on drawdown plan as soon as
USFWS approximate dates are determined (typically months in
advance).
Consult at least 10 days prior to beginning the reservoir
NCSHPO NCSHPO drawdown if the drawdown will affect Historic Properties
EBCI EBCI (NCSHPO) and include consultation with the EBCI if the
maintenance will result in a Large Extended Drawdown.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels).
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its reservoir
level toll-free phone system to inform the general public.
19
Abnormal Situation E.2 - Unscheduled Reservoir Drawdown
Mitigating Actions
1. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with the
resource agencies to (a) monitor any potential aquatic species impacts in the affected stream
segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation E.2 - Unscheduled Reservoir Drawdown
Notification Consultation Comments
If the drawdown cannot avoid impacting run-of-river
FERC NCDENR operations, perform notification as soon as possible, but no
NCDENR NCWRC longer than 5 days after the drawdown begins. Begin
NCWRC USFWS, NCSHPO, consultation within 10 days after the drawdown begins.
USFWS EBCI Include consultation with the NCSHPO if the drawdown will
affect Historic Properties and include consultation with the
EBCI if the drawdown will be a Large Extended Drawdown.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels).
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its
reservoir level toll-free phone system to inform the general
public.
20
Abnormal Situation F - Special River Access Circumstances
Mitigating Actions
1. Avoid Falling Below the Minimum Flow - To the extent practical, the Licensee will avoid falling
below the applicable Minimum Flow as noted above. If it is determined that 100 percent
exceedance of the Minimum Flow cannot reasonably be achieved, the Licensee will work with the
resource agencies to (a) monitor any potential aquatic species impacts in the affected stream
segments and (b) replace any aquatic species mortalities that are identified.
Communication with Resource Agencies and Affected Parties
Abnormal Situation F - Special River Access Circumstances
Notification Consultation Comments
If the Licensee must alter outflow from the Project such
that the stream flow will be reduced to a level that is below
NCDENR the Minimum Flow, then the Licensee will initiate
FERC NCWRC consultation as soon as possible after the dates are known,
USFWS but at least 10 days prior to beginning the temporary flow
alteration. Initiate consultation for unplanned river access
within 5 days after the temporary flow alteration begins.
Access Area The Licensee will conduct notification procedures for any
Closure temporary recreation facility/Access Area closures (e.g.,
Notification closure due to extended low reservoir levels.
As soon as possible after the Licensee determines that the
response to an abnormal situation will potentially impact
General license conditions, the Licensee will add appropriate
messages to its public information Web site and its
reservoir level toll-free phone system to inform the general
public.
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