20080915 Ver 1_Bridgewater repairs complete report to FERC_20161216

-- DUKE
ENERGY.
December 15, 2016
The Honorable Kimberly D. Bose, Secretary
Federal Energy Regulatory Commission
888 First Street, N.E.
Washington, DC 20426
RE: Notification of Scheduled Hydro Unit Maintenance
Catawba-Wateree Hydro Project P-2232-656
Bridgewater Development
Dear Secretary Bose:
WATER STRATEGY, HYDRO
LICENSING AND LAKE
SERVICES
Duke Energy Corporation
526 South Church Street
Charlotte, NC 28202
On September 19, 2016, Duke Energy Carolinas, LLC (Duke Energy) provided advance
notification of scheduled hydro unit maintenance at the Catawba-Wateree Hydroelectric Project
No. P-2232 (Project) Bridgewater Development to the Federal Energy Regulatory Commission
(Commission), the NC Department of Environmental Quality, the NC Wildlife Resources
Commission, the US Fish and Wildlife Service, and the City of Morganton.
After confirming no resource agency comments were received on the maintenance plan and
mitigation measures proposed by Duke Energy, the Commission on December 5, 2016,
approved the maintenance plan and mitigation measures and further required Duke Energy to
file a report within 15 days after the maintenance activities are concluded or by December 23,
2016, whichever comes first, covering the following three items.
1. The report should summarize the daily flows throughout the duration of the maintenance
repairs and should specifically identify whether Critical Flows were compromised, and to
what extent.
Duke Energy's Report: The work began on December 5 and the required repairs
extended one additional day to December 12. All repairs are now complete and all hydro
units have been returned to service. The continuous minimum flow requirement from the
Bridgewater Powerhouse at the time the original notification was submitted on
September 19 was 145 cubic feet per second (cfs) and the continuous minimum flow
requirement at the Catawba Dam was 75 cfs. Prior to beginning the work, the Catawba-
Wateree Basin Low Inflow Protocol (LIP) was escalated to Stage 1 on November 1,
2016, requiring Duke Energy to reduce these required flow releases to 103 cfs and 45
cfs respectively. These flows are higher than Critical Flows. Flow releases from the
Bridgewater Powerhouse during these days are summarized in Enclosure 1, showing
drops below the Critical Flow of 75 cfs during hours of no generation. Flow releases from
the Catawba Dam remained constant for the duration of the work at 52 cfs with no drops
below the Critical Flow of 25 cfs.

Kimberly Bose
Page 2
December 15, 2016
2. This monitoring of the effects on the minimum flow should provide information, including
leakage flow rates that would be valuable for future similar flow modifications that would
be necessary for maintenance issues.
Duke Energy's Report: Enclosure 1 represents flow release data collected from
powerhouse instrumentation and shows leakage flows dropped to approximately 1 cfs
consistently during non -generation periods. This information is roughly corroborated by
USGS Gage 02138520 (CATAWBA R AT SR1223 BL LK JAMES NR BRIDGEWATER,
NC), located just downstream of the powerhouse, which recorded leakage flows of from
0.5 cfs to just under 1 cfs
(http://waterdata.usgs.gov/nc/nwis/uv?cb 00060=on&cb 00065=on&format=gif default&
site no=02138520&period=&begindate=2016-12-05&end date=2016-12-12 ).
3. If the 75 cfs Critical Flow limit is exceeded during the repair time, you should notify the
North Carolina Wildlife Resources Commission; North Carolina Division of Water
Resources; and the U.S. Fish and Wildlife Service to that extent.
Duke Energy's Report: Now that the work is complete, these agencies are being notified
via copy of this letter of all associated flow releases.
Please contact Mark Oakley (704-382-5778; [e-mail]) or Lynne Dunn
(980-373-1578; [e-mail]) if there are questions or if further information is
needed.
Sincerely,
Jeffrey G. Lineberger, PE
Director, Water Strategy & Hydro Licensing
Duke Energy
Enclosure
cc w./ enclosure: Karen Higgins, North Carolina Department of Environmental Quality
Fred Tarver, North Carolina Department of Environmental Quality
Chris Goudreau, North Carolina Wildlife Resources Commission
Bryan Tompkins, United States Fish and Wildlife Service
Brad Boris, City of Morganton
George Galleher, Duke Energy
Lynne Dunn, Duke Energy
Mark Oakley, Duke Energy
Keith Finley, Duke Energy
Phil Fragapane, Duke Energy
Shannon Todd, Duke Energy

Enclosure 1: Flow releases from the Bridgewater Powerhouse between December 5, 2016, and
December 12, 2016
Flow releases from the Bridgewater Powerhouse between December 5, 2016, and December 12, 2016
are summarized below. The flows shown in bold red font, are the days and times when the flow release
was below the required LIP Stage 1 minimum flow release of 103 cfs as well as the Critical Flow of 75 cfs.
On Wednesday, December 7, the majority of the work did not involve divers so minimum flow was only
below the requirement for two hours.
Flow releases from the Catawba Dam remained constant at 52 cfs for the duration of the work
with no drops below the Critical Flow of 25 cfs.
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Monday
Time
12/5/
2016
12/6/
2016
12/7/
2016
12/8/
2016
12/9/
2016
12/10/
2016
12/11/
2016
12/12/
2016
0:00
115
113
161
142
148
155
110
110
1:00
115
113
161
142
148
155
110
110
2:00
115
113
161
142
148
155
110
110
3:00
115
113
161
142
148
155
110
110
4:00
115
113
161
142
148
155
110
110
5:00
113
113
161
142
148
158
110
110
6:00
115
113
161
142
148
155
110
110
7:00
115
113
17
142
27
1570
1510
110
8:00
1590
3
2
142
2
1610
1550
3
9:00
3
2
110
2
1
1610
1550
1
10:00
1
2
142
1
1
158
107
1
11:00
1
2
145
1
1
155
107
1
12:00
1
2
145
1
1
158
107
1
13:00
1
1
145
1
1
158
110
1
14:00
1
1
145
1
1
158
110
110
15:00
1
1
145
1
1
110
110
110
16:00
1
1
145
1
1
110
110
110
17:00
105
1
142
1
1
110
110
110
18:00
1560
1620
145
145
158
110
110
110
19:00
1570
1630
142
148
158
110
110
107
20:00
1570
1620
142
148
158
110
110
110
21:00
113
1640
142
148
158
110
110
110
22:00
113
161
142
148
155
110
110
107
23:00
113
161
142
148
158
110
110
107
0:00
113
161
142
148
155
110
110
107
Flow releases from the Catawba Dam remained constant at 52 cfs for the duration of the work
with no drops below the Critical Flow of 25 cfs.