20151008 Ver 4_401 Application_20180618

Geosptecl�l1300 S. Mint Street. Suite 300
Charlotte, North Carolina 28203
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VIA ELECTRONIC MAIL r.
Anthony Scarbraugh��'
Environmental Senior Specialist J(fN D
41
Washington Regional Office - Division of Water Resources 2�r1�
R'ohCarolina
Department
of Environment and Natural Resources Is TOM EQUat/N WashingtonSq R ERMITT/N
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Washington, NC 27889
Subject: Permit Modification: DWR EXP # 2015-1008 V3
Inactive Basin 2 Perimeter Dike Slope Stabilization
State Dam ID: WAYNE-032 (Exempt from NCDEQ Dam Safety Program)
H.F. Lee Energy Complex
Goldsboro, North Carolina
Wayne County
Dear Mr. Scarbraugh:
Geosyntec Consultants of North Carolina, PC (Geosyntec) is pleased to submit the following letter
and Pre -Construction Notification (PCN) form (Appendix A) to the U.S. Army Corps of Engineers
(USACE) and the North Carolina Department of Environmental Quality (NCDEQ) Division of
Water Resources (DWR) on behalf of our client Duke Energy Progress, LLC (Duke Energy) to
request modification of permit authorization 2015-1008 V3 issued on 15 August 2017. The
modification being requested by Duke Energy is to replace the Geosyntec permitted design (2015-
1008 V3) with the emergency and preventative stabilization construction measures implemented
by Duke Energy's Operations and Maintenance (O&M) construction group at the Inactive Basin
2 Perimeter Dike Stabilization Project ("HFLEE 125" or "Project") at the H.F. Lee Energy
Complex (H.F. Lee) in Wayne County, North Carolina (NC).
This letter is provided to DWR to provide written documentation of the following:
(1) A brief project and permit history for H.F. Lee's Inactive Basin 2 perimeter dike slope;
(2) A description of the as -built condition and deviations from the permitted design; and
(3) Supporting information for the emergency and preventative stabilization measure.
The O&M stabilization measures placed 680 linear feet (LF) of riprap along the northern
streambank of Halfmile Branch, which adds 70 LF of additional stabilization material than
included within the approved permit. The additional stabilization increases the total permanent
GC6204/Duke HFLEE 125—NCDEQ 401_Permit Mod_Cover.docx
engineers I scientists I innovators

Mr. Anthony Scarbraugh
18 May 2018
Page 2
bank stabilization for the Inactive Basin 2 dike slope to 855 LF. This total includes the following:
175 LF of permitted and constructed stabilization (Areas 1, 2, and 3) completed in 2015 (Appendix
B, Figure B 1), 610 LF of emergency riprap stabilization of Areas 4 through 10 completed in
September 2017 (Appendix B, Figure B 1), and 70 LF of emergency riprap stabilization (Area 11)
completed in September 2017 that was not authorized in the prior permit (Appendix B, Figure B 1).
The emergency and preventative stabilization was constructed with verbal approval from USACE
and NCDEQ prior to Hurricane Irma as an emergency and preventative slope stabilization
measure.
PROJECT AND PERMIT HISTORY
HFLEE-125 is adjacent to and associated with a prior Nationwide Permit (NWP) 13 bank
stabilization project (HFLEE-2) authorized by the USACE on 19 October 2015 (SAW -2015-
02107) and by NCDEQ on 29 September 2015 (DWR-15-1008). The 2015 project was initiated
to repair three areas (Areas 1, 2, and 3) along the exterior dike slope of Inactive Basin 2 where
erosional scarps and/or sloughing were observed (Appendix B, Figure BI). The project included
the placement of 175 LF of boulder toe protection below the ordinary high water mark (OHWM)
along the northern streambank of Halfmile Branch. In addition, riprap was placed upstream and
downstream of the boulder toe protection at the toe of slope for tie-in to the natural bank. Dike
slopes located above the boulder toe protection were cleared of vegetation, regraded, and stabilized
with riprap.
In late September and early October 2016 the HFLEE 125 project area experienced extensive
flooding and related damage as a result of Hurricane Matthew. Subsequent to the flooding, Duke
Energy personnel observed additional localized areas (Areas 4, 5, 6, 7, and 8) of erosional scarps
and/or sloughing along the exterior dike slope of Inactive Basin 2 (outside of the areas previously
repaired in 2015, which remain stable) (Appendix B, Figure B 1). Therefore, to repair the erosional
scarps and/or sloughs at five additional areas along the exterior dike slope of Inactive Basin 2, on
21 February 2017, Duke Energy submitted to the USACE a PCN for a NWP 13 for 408 LF of
additional boulder toe protection (Appendix B. Figure B 1).
On 27 April 2017, the USACE issued NWP 13 (SAW -2015-02107) for the proposed Project.
Additionally, on 20 March 2017, NCDEQ issued a 401 Water Quality Certification (WQC) and
riparian buffer variance exemption (DWR 2015-1008 V2). Subsequent to permit authorization and
prior to the start of construction, Duke Energy personnel observed erosional scarps and/or
sloughing at two additional areas (Areas 9 and 10) outside of the three areas repaired in 2015 and
the five areas authorized in April 2017 (Appendix B, Figure B 1). As such, to repair the observed
erosional scarps and/or sloughs, Duke Energy submitted to USACE and NCDEQ a permit
modification for 202 LF of additional boulder toe protection (Appendix B, Figure B 1).
GC6204/Duke HFLEE 125—NCDEQ 401_Permit_Mod_Cover.docx
engineers I scientists I innovators

Mr. Anthony Scarbraugh
18 May 2018
Page 3
On 15 August 2017, NCDEQ issued a 401 WQC and riparian buffer variance exemption (DWR
2015-1008-V3). Subsequently, the USACE issued NWP 13 (SAW -2015-02107) for the permit
modification on 07 September 2017.
EMERGENCY AND PREVENTATIVE SLOPE STABILIZATION MEASURE
In September 2017, following permit authorization and prior to construction, Hurricane Irma
approached the U.S. mainland and Duke Energy anticipated heavy rains and flooding at H.F. Lee.
In response, Duke Energy O&M installed an emergency and preventative slope stabilization
measure on the Inactive Basin 2 exterior southern dike slope to repair the observed scarps, reduce
erosion, and mitigate other potential flood impacts from Hurricane Irma.
The emergency and preventative slope stabilization measure included placement of riprap (Class
B) below the OHWM along 680 LF of the northern streambank of Halfmile Branch (Appendix B,
Figure BI). The 2017 issued USACE and NCDEQ permits authorized placement of up to 1.0 cubic
yards per running foot (cy/ft) of boulder toe protection below the OHWM along 610 LF (Areas 4
through 10) of the northern streambank of Halfmile Branch (Appendix B, Figure BI). The
emergency and preventative stabilization measure resulted in the following deviations from the
approved NCDEQ permit:
(1) Stabilization material installed below the OHWM along 680 LF of the northern
streambank of Halfmile Branch resulting in an additional 70 LF of streambank stabilization
than previously permitted;
(2) The stabilization measure was installed at shallower slopes than the permitted design and
replaced the boulder toe protection of permitted design with Class B riprap below the
OHWM; and
(3) An average of 1.04 cy/ft of riprap was placed below the OHWM.
CONCLUSION
As an emergency and preventative slope stabilization measure prior to Hurricane Irma, Duke
Energy, with verbal approval from the USACE and NCDEQ, implemented an emergency and
preventative stabilization measure along the Halfmile Branch dike and streambank. Duke Energy
O&M placed 680 LF of Class B riprap below the OHWM of Halfmile Branch for streambank
stabilization. Of the 680 LF of stabilization, 610 LF was in areas permitted in 2017, but not
constructed, and 70 LF was in an area not included in the 2017 permit authorizations. The
emergency and preventative stabilization measure resulted in deviations from the NCDEQ
authorized design including replacement of the boulder toe protection with riprap and the
GC6204/Duke HFLEE 125—NCDEQ 401_Permit_Mod_Covendocx
engineers I scientists I innovators

Mr. Anthony Scarbraugh
18 May 2018
Page 4
stabilization of an additional 70 LF (Area 11) of the northern streambank of Halfmile Branch. This
work brings the total permanent bank stabilization for the project to 855 LF, including 175 LF of
stabilization permitted and constructed in 2015.
Please see the attached supporting documentation for further details of the Project. If you have
any questions or need clarification regarding the information provided, feel free to contact Robert
Dunn at rdunn ,geosyntec.com or 678-202-9613 or David Vance at dvance2geosyntec.com or
678-202-9612 at your convenience.
Respectfully su�bmmiitt'ed,
Zz
David J. Vance, P.G. (GA)
Senior Scientist
mes D. McNash, P.E. (NC)
Project Engineer
Appendices: A. PCN Form for Emergency and Preventative Stabilization
B. Inactive Basin 2 Perimeter Dike Slope Stabilization Project (As -Built
Condition)
C. 13 July 2017 Permit Modification Package (Cover Letter and
Attachment A Only)
Copies to: USACE: Samantha Dailey
Duke Energy: Steve Cahoon, Issa Zarzar, Austin Mack
GC6204/Duke HFLEE 125_NCDEQ 401_ Permit_Mod_Cover.docx
engineers I scientists I innovators

Appendix A
PCN Form for Emergency and Preventative
Stabilization

0
�0F W ATF9OG
rRECEIVED
JUN 012018
DENR-LAND QUALITY
STORMWATER PERMITTING
Office Use Only:
Corps action ID no.
DWQ project no.
Form Version 1.4 January 2009
Page 1 of 10
PCN Form — Version 1.4 January 2009
Pre -Construction Notification (PCN) Form
A.
Applicant Information
1.
Processing
1 a.
Type(s) of approval sought from the Corps:
Q Section 404 Permit ❑ Section 10 Permit
1 b.
Specify Nationwide Permit (NWP) number: 13 or General Permit (GP) number:
1c.
Has the NWP or GP number been verified by the Corps?
0 Yes ❑ No
1 d.
Type(s) of approval sought from the DWQ (check all that apply):
❑ 401 Water Quality Certification — Regular ❑ Non -404 Jurisdictional General Permit
Q 401 Water Quality Certification — Express ❑ Riparian Buffer Authorization
1 e.
NO.
Is this notification solely for the record
because written approval is not required?
For the record only for DWQ
401 Certification:
® Yes ❑ No
For the record only for Corps Permit:
❑ Yes ® No
1f.
Is payment into a mitigation bank or in -lieu fee program proposed for
mitigation of impacts? If so, attach the acceptance letter from mitigation bank
or in -lieu fee program.
❑ Yes ® No
1 g.
Is the project located in any of NC's twenty coastal counties. If yes, answer 1 h
below.
❑ Yes ®No
1 h.
Is the project located within a NC DCM Area of Environmental Concern (AEC)?
❑ Yes ® No
2.
Project Information
2a.
Name of project:
H.F. Lee Inactive Basin 2 Perimeter Dike Slope Stabilization
2b.
County:
Wayne
2c.
Nearest municipality / town:
Goldsboro
2d.
Subdivision name:
N/A
2e.
NCDOT only, T.I.P. or state project no:
3.
Owner Information
3a.
Name(s) on Recorded Deed:
Duke Energy Progress, LLC
3b.
Deed Book and Page No.
DB 912 & PG 178; DB 939 & PG 3; DB 1024 & PG 565; DB 2819 & PG 766
3c.
Responsible Party (for LLC if
applicable):
Sharat C. Gollamudi, P.E.
3d.
Street address:
1677 Old Smithfield Road
3e.
City, state, zip:
Goldsboro, North Carolina, 27530
3f.
Telephone no.:
[phone]
3g.
Fax no.:
3h.
Email address:
[e-mail]
Page 1 of 10
PCN Form — Version 1.4 January 2009

4.
Applicant Information (if different from owner)
4a.
Applicant is:
❑ Agent ❑X Other, specify: Duke Energy Employee
4b.
Name:
Steve Cahoon, Lead Environmental Specialist
4c.
Business name
(if applicable):
Duke Energy Progress, LLC
4d.
Street address:
411 Fayetteville Street
4e.
City, state, zip:
Raleigh, NC 27601
4f.
Telephone no.:
919-546-7457 (office) & 919-632-0129 (cell)
4g.
Fax no.:
919-546-3669
4h.
Email address:
[e-mail]
5.
Agent/Consultant Information (if applicable)
5a.
Name:
David J. Vance, P.G.
5b.
Business name
(if applicable):
Geosyntec Consultants, Inc.
5c.
Street address:
1255 Roberts Blvd NW, Suite 200
5d.
City, state, zip:
Kennesaw, GA 30144
5e.
Telephone no.:
678-202-9612
5f.
Fax no.:
678-202-9501
5g.
Email address:
[e-mail]
Page 2 of 10

B.
Project Information and Prior Project History
1.
Property Identification
1a.
Property identification no. (tax PIN or parcel ID):
12579364163;2579551995;2579654670;2579754933
1 b.
Site coordinates (in decimal degrees):
Latitude: 35.383644 Longitude: -78.074003
1 c.
Property size:
233 acres
2.
Surface Waters
2a.
Name of nearest body of water to proposed project:
Halfmile Branch
2b.
Water Quality Classification of nearest receiving water:
WS -IV; NSW
2c.
River basin:
Neuse River
3.
Project Description
3a.
Describe the existing conditions on the site and the general land use in the vicinity of the project at the time of this
application:
Please Refer to PCN Cover Letter and permit modification package (previously submitted on 13 July 2017). Copy of the referenced
Cover Letter and permit modification package are attached.
3b.
List the total estimated acreage of all existing wetlands on the property: 36.42
3c.
List the total estimated linear feet of all existing streams (intermittent and perennial) on the property: 7,604
3d.
Explain the purpose of the proposed project:
Performed emergency streambank stabilization activities along 680 linear feet (previously authorized 610 linear feet) of Halfmile Branch prior to
Hurrican Irma resulting in an additional 70 LF of stabilization. Stabilization included placement of non -woven geotextile overlain by Class B riprap.
3e.
Describe the overall project in detail, including the type of equipment to be used:
Please Refer to PCN Cover Letter and permit modification package (previously submitted on 13 July 2017). Copy of the referenced
Cover Letter and permit modification package are attached.
4.
Jurisdictional Determinations
4a.
Have jurisdictional wetland or stream determinations by the
® Yes ❑ No ❑ Unknown
Corps or State been requested or obtained for this property /
project (includingall prior phases)in the past?
Comments:
4b.
If the Corps made the jurisdictional determination, what type
El Preliminary E] Final
of determination was made?
4c.
If yes, who delineated the jurisdictional areas?
Agency/Consultant Company:
Name (If known): Mr. Dicky Harmon
Other: AMEC - Foster Wheeler
4d.
If yes, list the dates of the Corps jurisdictional determinations or State determinations and attach documentation.
USACE site inspection 04/01/2015, follow up USACE inspection 04/21/2015, 3/22/16, 7/20/16 and 9/20/16
5.
Project History
5a.
Have permits or certifications been requested or obtained for
®Yes ❑ No ❑ Unknown
this project (including all prior phases) in the past?
5b.
If yes, explain in detail according to "help file" Instructions. Please refer to current PCN Cover Letter for NWP 13 modification.
USACE
NWP 13; Action Id: SAW -2015-02107; issued 10/19/2015, 04/27/2017, and 09!7/2017 NCDEQ ESCP; ESCP # Wayne 2016-014, issued 10/02/2015
NCDEQ
401 WQC'DWR EXP # 15-1008; issued 9/29/2015 NCDEQ ESCP; ESCP # Wayne 2017-021, issued 05/24/2017
NCDEQ
401 WQC', DWR EXP # 15-1008 V2; issued 03/20/2017 NCDEQ ESCP; ESCP # Wayne 2017-021, issued 08/16/2017
NCDEQ
401 WQC; DWR EXP # 15-1008 V3; issued 08/15/2017
6.
Future Project Plans
6a.
Is this a phased project?
❑ Yes ❑X No
6b.
If yes, explain.
Page 3 of 10
PCN Form — Version 1.4 January 2009

C. Proposed Impacts Inventory
1. Impacts Summary
1 a. Which sections were completed below for your project (check all that apply):
❑ Wetlands ❑X Streams — tributaries ❑X Buffers ❑ Open Waters ❑ Pond Construction
2. Wetland Impacts
If there are wetland impacts proposed on the site, then complete this question for each wetland area impacted.
2a.
Wetland impact
number
Permanent (P) or
Temporary T
2b.
Type of impact
2c.
Type of wetland
2d.
Forested
2e.
Type of jurisdiction
Corps (404,10) or
DWQ (401, other)
2f.
Area of
impact
(acres)
W1
Choose one
Choose one
Yes/No
-
W2
Choose one
Choose one
Yes/No
W3
Choose one
Choose one
Yes/No
W4
Choose one
Choose one
Yes/No
W5
Choose one
Choose one
Yes/No
-
W6 -
Choose one
Choose one
Yes/No
2g. Total Wetland Impacts:
2h. Comments:
3. Stream Impacts
If there are perennial or intermittent stream impacts (including temporary impacts) proposed on the site, then complete this
question for all stream sites impacted.
3a.
Stream impact
number
Permanent (P) or
Temporary (T)
3b.
Type of impact
3c.
Stream name
3d.
Perennial (PER) or
intermittent (INT)?
3e.
Type of
jurisdiction
3f.
Average
stream
width
(feet)
3g.
Impact
length
(linear
feet)
S1 P
Stabilization
Halfmile Branch
PER
CORPS
5
S2 P
Stabilization
Halfmile Branch
PER
CORPS
100
S3 P
Stabilization
Halfmile Branch
PER
CORPS
100
S4 P
Stabilization
Halfmile Branch
PER
CORPS
90
S5 P
Stabilization
Halfmile Branch
PER
CORPS
113
S6 P
Stabilization
Halfmile Branch
PER
CORPS
142
3h. Total stream and tributary impacts
see next page
3i. Comments:
See Appendix B for Figure depicting areas. (S1 -S6 Previously Permitted Areas) S1: Area 4 - 5 LF of streambank stabilization using rip -rap; S2 - Area 5 - 100 LF of
streambank stabilization using rip -rap; S3- Area 6- 100 LF of streambank stabilization using rip -rap; S4- Area 7- 90 LF of streambank stabilization using rip -rap; S5- Area 8 -
113 LF of streambank stabilization using rip -rap; S6 -Area 9 - 142 LF of streambank stabilization using rip -rap; (SEE NEXT PAGE FOR ADDITIONAL AREAS)
Page 4 of 10
PCN Form — Version 1.4 January 2009

3. Stream Impacts
If there are perennial or intermittent stream impacts (including temporary impacts) proposed on the site, then complete this
question for all stream sites impacted.
3a.
3b.
3c.
3d.
3e.
3f.
3g.
Stream impact
Type of impact
Stream name
Perennial (PER) or
Type of
Average
Impact
number
intermittent (INT)?
jurisdiction
stream
length
Permanent (P) or
width
(linear
Temporary (T)
(feet)
feet)
S7 P
Stabilization
Halfmile Branch
PER
CORPS
60
S8 P
Stabilization
Halfmile Branch
PER
CORPS
70
S9
Choose one
S4 -
Choose one
-
S5
Choose one
S6
Choose one-
-
3h. Total stream and tributary impacts
680
3i. Comments:
(Previously Permitted Area) S7- Area 10 - 60 LF of streambank stabilization using rip -rap; (THIS REQUEST) S8 - Area 11 (currently not permitted) - 70 LF of streambank
protection using rip -rap. WAIVER REQUEST: The project initially permanently stabilized 175 LF of streambank in 2015 (Areas 1, 2 and 3) and the USACE recently
authorized the permanent stabilization of Areas 4-8 (408 LF) and Area 9-10 (202) for a total of 785 LF. This modification requests an additional 70 LF of permanent
stabilization for Area 11 for a total of 855 LF. Therefore, this modification requests additional LF of bank stabilization beyond the NWP 13 500 LF limit.

4. Open Water Impacts
If there are proposed impacts to lakes, ponds, estuaries, tributaries, sounds, the Atlantic Ocean, or any other open water of
the U.S. then indivi ually list all open water impacts below.
4a.
Open water
impact number
Permanent (P) or
Temporary T
4b.
Name of waterbody
(if applicable)
4c.
Type of impact
4d.
Waterbody
type
4e.
Area of impact (acres)
01
Choose one
Choose
O2
Choose one
Choose
03
Choose one
Choose
04 -
Choose one
Choose
4f. Total open water impacts
4g. Comments:
5. Pond or Lake Construction
If pond or lake construction proposed, the complete the chart below.
5a.
Pond ID number
5b.
Proposed use or
purpose of pond
5c.
Wetland Impacts (acres)
5d.
Stream Impacts (feet)
5e.
Upland
(acres)
Flooded
Filled
Excavated
Flooded
Filled
Excavated
P1 PER
Choose one
P2 PER
Choose one
5f. Total:
5g. Comments:
5h. Is a dam high hazard permit required?
❑ Yes ❑ No If yes, permit ID no:
5i. Expected pond surface area (acres).-
acres):5j.
5j.Size of pond watershed (acres):
5k. Method of construction.-
onstruction:6.
6.Buffer Impacts (for DWQ)
If project will impact a protected riparian buffer, then complete the chart below. If yes, then individually list all buffer impacts
below. If any impacts require mitigation, then vou MUST fill out Section D of this form.
6a. Project is in which protected basin?
X❑ Neuse ❑ Tar -Pamlico ❑ Catawba ❑ Randleman ❑ Other:
6b.
Buffer Impact
number —
Permanent (P) or
Temporary T
6c.
Reason for impact
6d.
Stream name
6e.
Buffer
mitigation
required?
6f.
Zone 1
impact
(square
feet)
6g.
Zone 2
impact
(square
feet
61 T
Dam Slope Stabilization
Halfmile Branch
No
B2
Yes/No
B3
Yes/No
B4
Yes/No
B5
Yes/No
B6
Yes/No
6h. Total Buffer Impacts:
6i. Comments: Buffer permitting and mitigation is not required based on the dam stabilization project being required to provide stability for continued
safety and compliance with the NCDEQ Dam Safety Program
Page 5 of 10

D.
Impact Justification and Mitigation
1.
Avoidance and Minimization
1 a. Specifically describe measures taken to avoid or minimize the proposed impacts in designing project.
Please Refer to Page 7 and 8 (Avoidance and Minimization Section) of Appendix A of the Permit Modification Package (previously submitted on 13
July 2017). Copy of the referenced Permit Modification Package is attached.
1 b. Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques.
Please Refer to Page 7 and 8 (Avoidance and Minimization Section) of Appendix A of the Permit Modification Package (previously submitted on 13
July 2017). Copy of the referenced Permit Modification Package is attached.
2.
Compensatory Mitigation for Impacts to Waters of the U.S. or Waters of the State
2a.
Does the project require Compensatory Mitigation for
impacts to Waters of the U.S. or Waters of the State?
❑ Yes X❑ No
2b.
If yes, mitigation is required by (check all that apply):
❑ DWQ ❑ Corps
2c.
If yes, which mitigation option will be used for this
project?
❑ Mitigation bank
❑Payment to in -lieu fee program
❑ Permittee Responsible Mitigation
3.
Complete if Using a Mitigation Bank
3a.
Name of Mitigation Bank:
3b. Credits Purchased (attach receipt and letter)
Type: Choose one
Type: Choose one
Type: Choose one
Quantity:
Quantity:
Quantity:
3c.
Comments:
4.
Complete if Making a Payment to In -lieu Fee Program
4a.
Approval letter from in -lieu fee program is attached.
❑ Yes
4b.
Stream mitigation requested:
linear feet
4c.
If using stream mitigation, stream temperature:
Choose one
4d.
Buffer mitigation requested (DWQ only):
square feet
4e.
Riparian wetland mitigation requested:
acres
4f.
Non -riparian wetland mitigation requested:
acres
4g.
Coastal (tidal) wetland mitigation requested:
acres
4h.
Comments:
5.
Complete if Using a Permittee Responsible Mitigation Plan
5a.
If using a permittee responsible mitigation plan, provide a description of the proposed mitigation plan.
Page 6 of 10
PCN Form — Version 1.4 January 2009

6. Buffer Mitigation (State Regulated Riparian Buffer Rules) — required by DWQ
6a. Will the project result in an impact within a protected riparian buffer that requires
❑ Yes ❑X No
buffer mitigation?
6b. If yes, then identify the square feet of impact to each zone of the riparian buffer that requires mitigation. Calculate the
amount of mitigation required.
6c.
6d.
6e.
Zone
Reason for impact
Total impact
Multiplier
Required mitigation
(square feet)
(square feet)
Zone 1
3 (2 for Catawba)
Zone 2
1.5
6f. Total buffer mitigation required:
6g. If buffer mitigation is required, discuss what type of mitigation is proposed (e.g., payment to private mitigation bank,
permittee responsible riparian buffer restoration, payment into an approved in -lieu fee fund).
6h. Comments:
Buffer permitting and mitigation is not required based on the dam stabilization project being required to provide stability for continued
safety and compliance with the NCDEQ Dam Safety Program
Page 7 of 10

E.
Stormwater Management and Diffuse Flow Plan (required by DWQ)
1.
Diffuse Flow Plan
1a.
Does the project include or is it adjacent to protected riparian buffers identified
® Yes ❑ No
within one of the NC Riparian Buffer Protection Rules?
1 b.
If yes, then is a diffuse flow plan included? If no, explain why.
The
proposed work will not change diffuse flow characteristics of the existing ground beyond the toe of
❑ Yes ® No
the proposed dike slope stabilization.
2.
Stormwater Manage ent Plan
2a.
What is the overall percent imperviousness of this project?
0
2b.
Does this project require a Stormwater Management Plan?
❑ Yes ® No
2c.
If this project DOES NOT require a Stormwater Management Plan, explain why:
The
project does not trigger regulatory requirements for stormwater management beyond submittal of an erosion and sediment control plan and
issuance of a General Construction Stormwater Permit from NCDEQ.
2d.
If this project DOES require a Stormwater Management Plan, then provide a brief, narrative description of the plan:
2e.
Who will be responsible for the review of the Stormwater Management Plan?
3.
Certified Local Government Stormwater Review
3a.
In which localgovernment's jurisdiction is thisproject?
❑ Phase II
❑X NSW
3b.
Which of the following locally -implemented stormwater management programs
❑ USMP
apply (check all that apply):
0 Water Supply Watershed
❑ Other:
3c.
Has the approved Stormwater Management Plan with proof of approval been
EI Yes ® No
attached?
4.
DWQ Stormwater Program Review
❑Coastal counties
❑HQW
4a.
Which of the following state -implemented stormwater management programs apply
❑ORW
(check all that apply):
❑X Session Law 2006-246
❑ Other:
4b.
Has the approved Stormwater Management Plan with proof of approval been
❑ Yes ® No
attached?
5.
DWQ 401 Unit Stormwater Review
5a.
Does the Stormwater Management Plan meet the appropriate requirements?
® Yes ❑ No
5b.
Have all of the 401 Unit submittal requirements been met?
® Yes ❑ No
Page 8 of 10
PCN Form — Version 1.4 January 2009

F.
Supplementary Information
1.
Environmental Documentation (DWQ Requirement)
1 a.
Does the project involve an expenditure of public (federal/state/local) funds or the
❑ Yes ® No
use of public (federal/state) land?
1 b.
If you answered "yes" to the above, does the project require preparation of an
environmental document pursuant to the requirements of the National or State
❑ Yes ❑ No
(North Carolina) Environmental Policy Act (NEPA/SEPA)?
1 c.
If you answered "yes" to the above, has the document review been finalized by the
State Clearing House? (If so, attach a copy of the NEPA or SEPA final approval
letter.)
❑ Yes ❑ No
Comments:
2.
Violations (DWQ Requirement)
2a.
Is the site in violation of DWQ Wetland Rules (15A NCAC 2H .0500), Isolated
Wetland Rules (15A NCAC 2H .1300), DWQ Surface Water or Wetland Standards,
❑Yes ® No
or Riparian Buffer Rules (15A NCAC 2B .0200)?
2b.
Is this an after -the -fact permit application?
El Yes ® No
2c.
If you answered "yes" to one or both of the above questions, provide an explanation of the violation(s):
3.
Cumulative Impacts (DWQ Requirement)
3a.
Will this project (based on past and reasonably anticipated future impacts) result in
❑ Yes ® No
additional development, which could impact nearby downstream water quality?
3b.
If you answered "yes" to the above, submit a qualitative or quantitative cumulative impact analysis in accordance with the
most recent DWQ policy. If you answered "no," provide a short narrative description.
4.
Sewage Disposal (DWQ Requirement)
4a.
Clearly detail the ultimate treatment methods and disposition (non -discharge or discharge)
of wastewater generated from
the proposed project, or available capacity of the subject facility.
There is no sewage disposal involvement in this project.
Page 9 of 10
PCN Form — Version 1.4 January 2009

S. Endangered Species and Designated Critical Habitat (Corps Requirement)
5a. Will this project occur in or near an area with federally protected species or
❑ Yes No
habitat?
5b. Have you checked with the USFWS concerning Endangered Species Act
© Yes ❑ No
impacts?
5c. If yes, indicate the USFWS Field Office you have contacted.
=Raleigh
5d. What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical
Habitat?
U.S Fish and Wildlife Service - IPAC and NC Wayne County List, North Carolina Natural Heritage Program
6. Essential Fish Habitat (Corps Requirement)
6a. Will this project occur in or near an area designated as essential fish habitat?
❑ Yes ® No
6b. What data sources did you use to determine whether your site would impact Essential Fish Habitat?
National Marine Fisheries Service, South Atlantic Fishery Management Council - Essential Fish Habitat Mapper
7. Historic or Prehistoric Cultural Resources (Corps Requirement)
7a. Will this project occur in or near an area that the state, federal or tribal
governments have designated as having historic or cultural preservation
❑ Yes ® No
status (e.g., National Historic Trust designation or properties significant in
North Carolina history and archaeology)?
7b. What data sources did you use to determine whether your site would impact historic or archeological resources?
North Carolina State Historic Preservation Office
8. Flood Zone Designation (Corps Requirement)
8a. Will this project occur in a FEMA -designated 100 -year floodplain?
® Yes ❑ No
8b. If yes, explain how project meets FEMA requirements:
The Project will be performed in compliance with federal and local FEMA 100 -year floodplain requirements. The proposed Project will not introduce
any fig Into the floodplain.
8c. What source(s) did you use to make the floodplain determination?
FEMA Digital Flood Insurance Rate Map and FEMA data
Applicant/Agenfs Printed Name
Applicant/Agent's Signature
Date
(Agent's signature is valid only If an authorization
letter from the applicant Isprovided.)
Page 10 of 10

Appendix B
Inactive Basin 2 Perimeter Dike Slope
Stabilization Project (As -Built Condition)

zlw
Y L
Area 11 (70LF)
�♦♦♦♦♦
�� tl17♦♦'
������! _ �♦�♦��♦„�♦,♦rirr��t, ♦ !♦♦Ti'♦��♦����r..♦yam♦��Fi��a��i� .:..r-�-- -
�
Y Y
No Riprap from
- r _.� - emergency repair is
placed below the
OHWM in Areas 1, 2,
and 3 even though the
green hatch extends
"�-- beyond the boulder toe
into the channel
bottom.
LEGEND
EXISTING GROUND ELEVATION (FEET) (NOTES 1 AND 2)
70 DESIGN GRADE ELEVATION (FEET)
FLOW DIRECTION
EXISTING DIKE CREST
ORDINARY HIGH WATER MARK (PLAN VIEW)
50 -FT STREAM BUFFER
EXISTING BOULDER TOE
PROPOSED BOULDER TOE
AS -BUILT LOCATION OF RIP RAP (NOTE 3)
NOTES:
1. TOPOGRAPHIC AND STREAM INFORMATION OBTAINED FROM WSP
GROUP USA SURVEY PREPARED FOR DUKE ENERGY PROGRESS,
LLC OF THE H.F. LEE PLANT INACTIVE BASIN, REVISION 4, DATED
25 OCTOBER 2013. TOPOGRAPHIC INFORMATION IS BASED ON
AERIAL PHOTOGRAPHY AND LIMITED GROUND SURVEY
INFORMATION. TOPOGRAPHIC INFORMATION IS APPROXIMATE
AND MAY NOT REFLECT ACTUAL FIELD CONDITIONS OF THE
EXISTING GROUND SURFACE DUE TO HEAVY VEGETATIVE COVER
DURING AERIAL SURVEY. LIMITED TOPOGRAPHIC INFORMATION
OF REPAIRED AREAS 1, 2, AND 3 WAS COLLECTED BY SURVEYING
SOLUTIONS, P.C. AND PROVIDED ON 21 DECEMBER 2015.
2. AS -BUILT INFORMATION OBTAINED FROM A SURVEY PREPARED
BY WSP USA, INC AND DATED 25 SEPTEMBER 2017.
3. COORDINATES ARE BASED ON NORTH CAROLINA STATE PLANE
GRID SYSTEM, NORTH AMERICAN DATUM OF 1983 (NAD83).
ELEVATIONS ARE BASED ON NORTH AMERICAN DATUM OF 1988
(NAVD88).
N
0 60' 120'
SCALE IN FEET

s
• 77.0
� ...... • 78.5
L 'al 1--, • 77.6
77
1. BASIS OF BEARINGS.' NCGS GRID COORDINATES, NAD 83/11 DATUM.
2. VERTICAL DATUM NAVD88.
3. CONTOUR INTERVAL IS ONE FOOT, MAJOR (5 FOOT CONTOURS] LABELED.
4. FIELD SURVEYS COMPLETED ON SEPTEMBER 19TH TO SEPTEMBER 21ST.
5. ALL DISTANCES ARE HORIZONTAL GROUND DISTANCES IN U.S. SURVEY FEET UNLESS
OTHERWISE NOTED.
6. THE AREA SHOWN HEREON WAS COMPUTED USING THE COORDINATE COMPUTATION METHOD.
7. LINES NOT SURVEYED ARE SHOWN AS BROKEN LINES FROM INFORMATION REFERENCED ON
THE FACE OF THIS PLAT.
B. THE ENTRE SURVEYED AREA IS LOCATED WITHIN ZONE AE (FLOODWAY) FLOOD HAZARD
AREA ACCORDING TO FLOOD INSURANCE RATE MAPS: MAP/3720256800J PANEL 2568 LAST
REVISED 12/02/05
9. LOCATION OF UTILITIES, WHETHER PUBLIC OR PRIVATE, IS BASED UPON FIELD LOCATION OF
VISIBLE APPURTENANCES N CONJUNCTION WITH INFORMATION PROVIDED BY THE OWNERS OF
SAID UTILITIES AND ARE APPROAMATE ONLY. IT IS THE CONTRACTOR'S RESPONSOUTY TO
VERIFY LOCATION PRIOR TO COMMENCEMENT OF ANY CONSTRUCTION. WSP CANNOT ASSUME
RESPONSIBILITY FOR MISIDENTIFICATION OR OMISSION OF UNDERGROUND UTILITIES. DUE TO
OSHA REQUIREMENTS PERTAINING TO CONFINED SPACE ENTRY, PIPE SIZES. INVERT
ELEVATIONS, ETC., WILL ONLY BE PROVIDED IF FIELD PERSONNEL ARE ABLE TO OBTAIN
WITHOUT BREAKING THE PLANE OF THE TOP OF THE STRUCTURE.
10. PROPERTY SUBJECT TO ALL EASEMENTS AND RESTRICTIONS OF RECORD.
11. STUMP SIZES IN CHART ARE DIAMETER IN INCHES. STUMPS WITH MULTIPLE MEASUREMENTS
ARE SPUT/MULTIPLE STUMPS
GRAPHIC SCALE
b 0 30 00 120 240
( IN FEET )
1 inch - 60 11.
1 LINES PROVIDED FROM FLOOD
MAP 3720256800) PANEL 2568
P NUMBER
STUMP SZE
1
11"
2
10"
3
7" 8"
4
10", 13"
5
11% 12'
6
10'
7
11'
�J • 77.4
STUMP NUMBER
STUMP SIZE
8
16"
9
13"
10
16"
11
16"
12
17'
13
13'
14
15'
15
6". 8'. 8"
16
16"
17
16'
18
17"
19
12"
20
14", 16', 17"
21
11"
22
11', 14"
23
10'
24
17'
25
IV
26
7', 13"
27
9"
28
10"
29
6" 8"
• 76.4
STUMP NUMBER
STUMP SIZE
30
10"
31
8', 12". 12"
32
16", 18-
33
15"
34
23'
35
15"
36
20"
37
7'
38
15"
39
17'
40
17"
41
8-
42
22"
43
8", 12"
44
V. 17", 17"
45
6"
46
17"
47
8"
48
12", 16"
49
10"
50
8"
51
17'
STUMP NUMBER
STUMP SIZE
52
19"
53
1V
54
17"
55
21"
56
20"
57
6-
58
17-
59
5'
60
4-
61
7-
62
7-
63
2", 3-
64
10'
65
20"
66
12-
67
3-
68
5", 10", 14"
69
11"
70
7", 16-
71
10'
72
20"
73
5", 6"
. 73.88
1621 Y
STUMP
CONTROL POINT / BENCHMARK
PIEZOMETER
SPOT SHOT
MAJOR CONTOUR
MINOR CONTOUR
FLOOD ZONE LINE
TOPO LIMITS
CENTERUNE OF CREEK
RIP RAP AREA
POINT NUMBER
NORTHING
EASTING
ELEVATION
2041
$94067.26
2266313.90
78.62
2238
593901.35
2266595.02
78.91
2491
593682.79
2266903.77
78.30
2594
593656.15
2266963.07
79.44
� \ REVISION
... ...
w, DATE DESCRIPTION
.� •75.8
DUKE ENERGY H.F. LEE SITE
•72.4\."'°M..,..,.80.0 1677 OLD SMITHFIELD ROAD
�111'° GOLDSBORO, NORTH CAROLINA
rOpo �� PREPARED FOR
•73.2..,: :.,. •;. .80.7 I spr i
.74.7
GEOSYNTEIC CONSULTANTS OF NC, PC
TOPOGRAPHIC SURVEY CERTIFICATION 2T� ("74.8
✓
1, BARRY W. CREED, CERTIFY THAT THIS PROJECT WAS COMPLETED UNDER. ahlQ WSP USA Inc.
MY DIRECT AND RESPONSIBLE CHARGE FROM AND ACTUAL SURVEY MADE �'Rly 128 TALBERT ROAD
UNDER MY SUPERVISION; THAT THIS GROUND SURVEY WAS PERFORMED AT*
\\ NNSUA
THE 95 PERCENT CONFIDENCE INTERVAL TO MEET FEDERAL GEOGRAPHIC ,pIp11U11//l,� r'sc % I ) TEL, S
DATA COMMITTEE STANDARDS; THAT THIS SURVEY WAS PERFORMED TO p``1 CAq 'fl, � • 78.2 LAOORESIILLE, NC 28117
MEET THE REQUIREMENTS FOR A TOPOGRAPHIC/PLANIMETRIC SURVEY TO 'tf• %'• �, 3.7 ® \yW,NrSp,CpM 1�
THE ACCURACY OF CLASS A AND VERTICAL ACCURACY WHEN APPUCABLE �tis.Z,
TO THE CLASS A STANDARD, AND THAT THE ORIGINAL DATA WAS OBTAINED - Z{ t� _ 21
ON 9-19-17; THAT THE SURVEY WAS COMPLETED ON 9-21-17; THAT
CONTOURS SHOWN AS BROKEN LINES MAY NOT MEET THE STATED
STANDARD, AND ALL COORDINATES ARE BASED ON NAD 83 (2011) AND ALL
ELEVATI ARE BA ON NADV �,• • .,, �� • 74.3' _- Drawn By TCB Date Job No.
g/Z /��� W. 1�.�` Surveyed By JC,C , SEPTEMBER 28, 2017
E/ UIII1111111111`
ARRY .. CREED DA Chocked BY BWC 1MSc=a BO S OF O.1
Book No. -

Appendix C
13 July 2017 Permit Modification
Package (Cover Letter and
Attachment A Only)

Geosptecc:l
consultants
13 July 2017
VIA ELECTRONIC MAIL
Samantha Dailey
Regulatory Specialist
U.S. Army Corps of Engineers
Wilmington District - Regulatory Division
3331 Heritage Trade Drive, Suite 105
Wake Forest, NC 27587
1300 S. Mint Street. Suite 300
Charlotte, North Carolina 28203
PH 704.227.0855
FAX [phone]
N"".geosyntec.com
Subject: Permit Modification — SAW -2015-02107
Inactive Basin 2 Perimeter Dike Slope Stabilization
State Dam ID: WAYNE-032 (Exempt from NCDEQ Dam Safety Program)
H.F. Lee Energy Complex
Goldsboro, North Carolina
Wayne County
Dear Ms. Dailey:
Geosyntec Consultants of North Carolina, PC (Geosyntec) is pleased to submit the following letter
to the U.S. Army Corps of Engineers (USACE) and the North Carolina Department of
Environmental Quality (NCDEQ) Division of Water Resources (DWR) on behalf of our client
Duke Energy Progress, LLC (Duke Energy) to request modification of respective permit
authorizations (SAW -2015-02107 issued on 27 April 2017 and 2015-1008 V2 issued on 20 March
2017) for the proposed construction activities associated with the Inactive Basin 2 Perimeter Dike
Stabilization Project ("HFLEE 125 Project" or "Project") at the H.F. Lee Energy Complex (H.F.
Lee) located in Wayne County, North Carolina near the town of Goldsboro.
This letter is provided to the USACE to provide written documentation of the following:
(1) A brief project and permit history for H.F. Lee's Inactive Basin 2 perimeter dike slope;
(2) A description of the proposed project modification; and
(3) Supporting information for the proposed modification.
The proposed modification would add 202 linear feet (LF) of additional boulder toe protection on
Halfmile Branch and stabilization along the perimeter dike slope of Inactive Basin 2 at H.F. Lee.
This proposed work would bring the total requested permanent bank stabilization for the project
from 583 linear feet (LF) to 785 LF. No project work has commenced under SAW -2015-02107.
GC6204/Duke HFLEE 125—USACE—Permit—Mod—Cover Letter July 13 2017.docx
engineers I scientists I innovators

Ms. Samantha Dailey
13 July 2017
Page 2
PROJECT AND PERMIT HISTORY
The Project is adjacent to and associated with a prior Nationwide Permit (NWP) 13 bank
stabilization project authorized by the USACE on 19 October 2015 (SAW -2015-02107) and by
North Carolina Department of Environmental Quality (NCDEQ) on 29 September 2015 (DWR-
15-1008). The 2015 project was initiated to repair three areas along the exterior dike slope of
Inactive Basin 2 where erosional scarps and/or sloughing were observed. The project included the
placement of 175 LF of boulder toe protection below the ordinary high water mark (OHWM) along
the northern streambank of Halfmile Branch. Additionally, riprap was placed upstream and
downstream at the toe, adjacent to the boulder toe protection for tie-in to the natural bank. Dike
slopes located above the boulder toe protection were cleared of vegetation, regraded, and stabilized
with riprap.
In late September and early October 2016 the H.F. Lee 125 project area experienced extensive
flooding and related damage as a result of Hurricane Matthew. Subsequent to the flooding, Duke
Energy personnel observed additional localized areas of erosional scarps and/or sloughing along
the exterior dike slope of Inactive Basin 2 (outside of the areas previously repaired in 2015, which
remain stable). Therefore, to repair the erosional scarps and/or sloughing at five additional areas
along the exterior dike slope of Inactive Basin 2, on 21 February 2017, Duke Energy submitted to
the USACE a Pre -Construction Notification (PCN) for a NWP 13 for 408 LF of additional boulder
toe protection (Attachment A — Cover Letter only).
On 27 April 2017, the USACE issued NWP 13 (SAW -2015-02107) for the proposed Project.
Additionally, on 20 March 2017, North Carolina Department of Environmental Quality (NCDEQ)
issued a 401 Water Quality Certification and riparian buffer variance exemption (DWR 2015-1008
V2). Subsequent to permit authorization and prior to construction commencing, Duke Energy
personnel observed erosional scarps and/or sloughing at two additional areas outside of the three
areas repaired in 2015 and the five areas authorized in April 2017. Therefore, to repair the observed
erosional scarps and/or sloughing, Duke Energy is requesting a modification (described below) to
the issued authorizations from USACE and NCDEQ to include the two additional areas into the
proposed Project.
PROPOSED PROJECT MODIFICATION
The proposed Project modification includes placement of additional boulder toe protection along
202 LF of the northern streambank of Halfmile Branch to address two new areas of instability
(Attachment B for PCN Form; Attachment C: Areas 9 and 10 on Drawings 4, 5 and 7). Area 9
(142 LF, 0.00068 ac) and Area 10 (60 LF, 0.0016 ac) are located immediately adjacent to each
other, downstream of previously repaired Area 2 and upstream of previously repaired Area 3
(Attachment C: Drawings 3 through 5) and work in these areas is designed as one continuous
GC6204/Duke HFLEE 125_USAC E_Permit_Mod_Cover Letter July 13 2017.doca
engineers I scientists I innovators

Ms. Samantha Dailey
13 July 2017
Page 3
streambank repair along 202 LF of Halfmile Branch. Terminal riprap protection on Areas 2
(downstream end of boulder toe protection) and 3 (upstream end of boulder protection) from the
2015 repairs is currently in place, therefore this material would be removed to allow for tie-in of
proposed boulder toe to existing boulder toe. The total discharge of material placed below the
OHWM would be less than the maximum cubic yard per running foot.
The current design includes the placement of riprap for upper dike slope stabilization at all areas
as opposed to the use of fabric formed articulating block mat proposed previously. A Temporary
Bypass Plan (Attachment C: Drawing 9) would be utilized to temporarily dewater the stream
channel of Halfmile Branch. The Temporary Bypass Plan would be implemented using the same
methods and materials proposed in the existing permitted design.
CONCLUSION
Duke Energy proposes to modify the existing permit authorization (SAW -2015-02107) to include
boulder toe protection along an additional 202 LF of the northern streambank of Halfmile Branch
at two areas, Area 9 (142 LF) and Area 10 (60 LF) in addition to the previously authorized areas
(408 LF and 175 LF) for a total of 785 LF.
Please see the attached supporting documentation for further details of the Project. If you have
any questions or need clarification regarding the information provided, feel free to contact Robert
Dunn at rdunnAgeosyntec.com or 678-202-9613 or David Vance, P.G. at dvance(a, eosyntec.com
or 678-202-9612 at your convenience.
Respectfully submitted,
David J. Vance, P.G.
Senior Scientist
Attachment: A. 21 February 2017 PCN Cover Letter for Recently Permitted Project
B. PCN Form for Proposed Modification
C. Inactive Basin 2 Perimeter Dike Slope Stabilization Project Design
Drawings (Current Design)
Copies to: NCDEQ: Anthony Scarbraugh
Duke Energy: Steve Cahoon, Cedric Fairbanks, Issa Zarzar, Henry Hardy, Jr.,
Austin Mack
GC6204/Duke HFLEE 125_USACE_Permit_Mod—Cover—Letter—July 13 2017.docx
engineers I scientists I innovators

Appendix A
21 February 2017 PCN Cover Letter for Recently
Permitted Proj ect

Geosynteccl'
consultants
VIA ELECTRONIC MAIL
Samantha Dailey, Regulatory Specialist
U.S. Army Corps of Engineers
Wilmington District - Regulatory Division
3331 Heritage Trade Drive, Suite 105
Wake Forest, NC 27587
1300 S. Mint Street. Suite 300
Charlotte. North Carolina 28203
PH 704.2220855
FAX [phone]
N ww.geosyntec.com
21 February 2017
Subject: Pre -Construction Notification — Nationwide Permit 13
Inactive Basin 2 Perimeter Dike Slope Stabilization
State Dam ID: WAYNE-032 (Exempt from NCDEQ Dam Safety Program)
H.F. Lee Energy Complex
Goldsboro, North Carolina
Wayne County
Dear Ms. Dailey:
Geosyntec Consultants of North Carolina, PC (Geosyntec) is pleased to submit the enclosed Pre -
Construction Notification (PCN) application (Attachment A) to the U.S. Army Corps of Engineers
(USACE) on behalf of our client, Duke Energy Progress, LLC (Duke Energy). This PCN
application is for authorization of the proposed construction activities associated with Inactive
Basin 2 Perimeter Dike Stabilization Project ("HFLEE 125 Project" or "Project") at the H.F. Lee
Energy Complex (H.F. Lee) located in Wayne County, North Carolina near the town of Goldsboro
(Figure 1). The Project is adjacent to and associated with a prior bank stabilization project
authorized by the USACE on 19 October 2015 (SAW -2015-02107).
The proposed Project has been designed to repair five areas of observed erosional scarps and/or
sloughing of the exterior dike slope of Inactive Basin 2, which is also the northern bank of Halfmile
Branch (Figures 2 and 3) a perennial tributary to the Neuse River. The purpose of the proposed
Project is to stabilize the perimeter dike slope of Inactive Basin 2 through the installation of boulder
toe protection (from ordinary high water mark (OHWM) to toe of bank) and fabric formed
articulating block mat (above OHWM for dike slope protection). Attachment B contains the design
drawings for the Project that illustrate the limits of each stabilization method. Cumulative impacts
of the previous stabilization work in 2015 and the proposed Project exceed 500 linear feet (LF),
therefore Duke Energy is requesting a waiver of the 500 LF criterion and authorization of the
proposed Project under a Nationwide Permit (NWP) 13 for bank stabilization. Additionally, Duke
GC6204/Duke HFLEE 125—PCN—Cover Letter .docx
engineers I scientists I innovators

Ms. Samantha Dailey
21 February 2017
Page 2
Energy is requesting authorization from the North Carolina Department of Environmental Quality
(NCDEQ) Division of Water Resources (DWR) for the proposed work as an "allowable" activity
for dike maintenance within the 50 -foot (ft) riparian buffer of Halfmile Branch.
PROJECT BACKGROUND
The 2015 bank stabilization project was authorized under a USACE NWP 13 SAW -2015-02107
and NCDEQ 401 Water Quality Certification DWR-15-1008 (Attachment C). The 2015 project
(Attachment D) was initiated to address three areas along the exterior dike slope of Inactive Basin
2 where erosional scarps and/or sloughing were observed. To repair the erosional scarps and/or
sloughing, the 2015 project included the placement of 175 LF of boulder toe protection below the
OHWM along the northern streambank of Halfmile Branch. Additionally, riprap was placed
upstream and downstream at the toe, adjacent to the boulder toe protection for tie-in to the natural
bank. Dike slopes located above the boulder toe protection were cleared of vegetation, regraded,
and stabilized with riprap at a 1.5 horizontal to 1 vertical (1.5H:IV) slope angle and tied into the
top of the existing dike slope.
In late September and early October 2016, Hurricane Matthew, a Category 1 storm, caused severe
weather including heavy rainfall to eastern North Carolina. As a result, H.F. Lee experienced
extensive flooding and damage in October 2016. Subsequent to the severe weather, Duke Energy
personnel observed additional localized areas of erosional scarps and/or sloughing along the
exterior dike slope of Inactive Basin 2 (outside of the areas previously repaired in 2015, which
remain stable). Therefore, Duke Energy is proposing to repair erosional scarps and/or sloughing
at five additional areas along the exterior dike slope of Inactive Basin 2.
PROJECT DESCRIPTION
The proposed Project design (Attachment B) addresses stabilization needs for five areas of the
south -facing perimeter dike slope of Inactive Basin 2 abutting Halfmile Branch, a perennial
tributary to the Neuse River. The Project is comprised of three components:
• Permanent in -channel dike slope/streambank stabilization (boulder toe) of Halfmile
Branch below the OHWM;
GC6204/Duke HFLEE 125—PCN—Cover Letter .docx
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Ms. Samantha Dailey
21 February 2017
Page 3
• Permanent upper dike slope stabilization above the OHWM but within the northern (left
bank) 50 -foot (ft) riparian buffer of Halfmile Branch will include removal of vegetation
and large debris and installation of a fabric formed articulating block mat; and
• Temporary dewatering and bypass plan involving temporary, hand -placed materials and
pump equipment within the southern (right bank) 50 -ft riparian buffer of Halfmile Branch
along with the placement of sand bags for instream work.
Halfmile Branch Streambank Stabilization
The proposed Project will require placement of permanent stabilization material along 408 LF of
the northern streambank of Halfmile Branch (Attachment B, Drawings 4 through 7). The
permanent stabilization material will be placed at five areas: Area 4 (5 LF), Area 5 (100 LF), Area
6 (100 LF), Area 7 (90 LF), and Area 8 (113 LF). Area 4, Area 5, Area 6, and Area 7 are located
immediately adjacent to each other, upstream of previously repaired Area 1 (Attachment B,
Drawing 3 and 5) and work in these areas is designed as one continuous streambank repair along
295 LF of Halfmile Branch. Area 8 is located at the downstream end of the Project area,
immediately upstream and adjacent to previously repaired Area 3 (Attachment B, Drawing 3 and
5).
The primary permanent stabilization material proposed below the OHWM for bank toe protection
is boulders. To transition the stream between native soil streambank and the boulder toe wall, two
(2) feet or greater diameter riprap (underlain by a non -woven geotextile) for streambank transition
protection is proposed along 6 LF upstream and downstream at the toe, adjacent to the boulder
protection. This approach provides greater streambank stability by minimizing the transition
between vegetated slopes and boulder toe protection.
The riprap protection will be placed upstream of Area 4 and downstream of Area 8. The riprap
protection upstream of Area 4 is located entirely within uplands, while the riprap protection
downstream of Area 8 will be placed below the OHWM. Riprap protection from the 2015 repairs
is currently in place downstream of Area 7 and upstream of Area 8, therefore this material will be
removed to allow for tie-in of proposed boulder toe to existing boulder toe. This riprap has been
sized per the USACE Wilmington District Regional Conditions. The total discharge of boulders
and riprap will also be less than the maximum cubic yard per running foot.
GC6204/Duke HFLEE 125—PCN—Cover Letter .docx
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Ms. Samantha Dailey
21 February 2017
Page 4
All construction activities will be performed according to the HFLEE 125 Project's Erosion and
Sediment Control Plan (as shown in Attachment B, Drawings 4 through 8 and 10), which was
developed in accordance with the Sedimentation and Pollution Control Act of 1973. No fill is
proposed within the channel for construction access, and no clearing or disturbance of the right
bank and associated riparian buffer of Halfmile Branch is proposed. Construction is anticipated
to require up to 15 days for each Area for final stabilization, for a total of up to 75 days of total
construction (including the components described below).
Upper Dike Slope Stabilization
The upper dike slope above the OHWM will require vegetation, debris, and failed soil mass
removal at each stabilization area, re -grading the slopes to 2H:1 V, and placement of fabric formed
articulating block mat for final dike slope stabilization (Attachment B, Drawings 4 through 7).
Mechanical removal of vegetation (i.e. excavator or feller-buncher) is proposed along the dike
slopes of Inactive Basin 2 to facilitate site access and stabilization activities. Clearing of vegetation
will be limited to above ground and will include stump removal as necessary for installation of
boulder toe protection and fabric formed articulating block mat.
Dike slopes located above the boulder toe (408 LF) and 38 LF of dike slopes upstream of the
boulder toe in Area 4 will be regraded (to design grades), stabilized with fabric -formed articulating
block mats at a 2H:1 V slopes, and anchored into the dike crest via an anchor trench (Attachment
B, Drawings 4 through 7). The proposed use of fabric formed articulating block mats for slope
stabilization rather than use of riprap as in the 2015 is selected to provide a stabilization method
with less routine maintenance over the remaining life of the basin. Additionally, the 2017 design
applies less load per square foot and still protects the slope from erosion.
To achieve a 2H:1 V grades of the dike slope, the dike crest/access road will be relocated north by
no greater than 15 feet to the interior of Inactive Basin 2. In areas not undergoing upper dike slope
stabilization, existing trees will be cut with stumps left in place and treated with AnchorSeal"-- (as
shown in Attachment B, Drawing 9). Mechanically cleared areas of the exterior dike not receiving
fabric formed articulating block mat will be stabilized with a mix of native herbaceous plant
species (as detailed in Attachment B, Drawing 10). Streambank stabilization activities will take
place on the northern (left bank) 50 -foot riparian buffer of Halfmile Branch, which is also the
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exterior dike slope of Inactive Basin 2. Therefore, the activities proposed are "allowable" under
Neuse River riparian buffer rules.
Dewatering and Bypass Plan
The stream channel of Halfmile Branch will be temporarily dewatered according to the Temporary
Bypass Plan (Attachment B, Drawing 8). The purpose of the Temporary Bypass Plan is to
temporarily dewater the active construction area to minimize potential erosion and construction
complications, and to facilitate construction access, placement of boulder toe protection, and
streambank protection installation. The Temporary Bypass Plan will pump stream flow around
the construction areas, and will be facilitated by temporary placement of coffer dams (hand -placed
sand bags) and sump pits, pumps and bypass discharge lines. Temporary bypass equipment will
be placed at two locations during construction (Attachment B, Drawing 8). First, temporary bypass
equipment will be placed immediately upstream of Area 8 to facilitate construction of the repair.
Upon completion of construction of Area 8, temporary bypass equipment will be placed upstream
of Area 4 to facilitate construction of Areas 4 through 7.
Four (4) temporary coffer dams for stream flow bypass will be installed at the upstream and
downstream limits of both work areas (Areas 4 through 7 and Area 8). These coffer dams will
provide three functions: (i) restrict upstream inflows to the construction area; (ii) contain sediment -
laden water generated during placement of the boulder toe and streambank protection, and (iii)
prevent potential inflow of backwater from the Neuse River should the river stage up due to flood
waters. Any water accumulated within the construction area, and contained by the coffer dams
(anticipated to be a small volume of water, less than or equal to a typical precipitation event) will
be actively pumped (as needed) into Inactive Basin 2 during and at completion of stabilization
activities.
EXISTING CONDITIONS
Geosyntec performed multiple field visits in 2014 and 2015 prior to the repair of Areas 1, 2, and
3. Field visits have also been conducted in 2016 to assess the condition of eroded Areas 4, 5, 6, 7,
and 8. Over the course of the field visits, Geosyntec has observed Halfmile Branch in no flow,
low -flow, high-flow, and back -water conditions. Attachment E contains relevant photographs of
Halfmile Branch within the Project Area, proceeding from the upstream end of the Project Area to
the downstream end. The photographs illustrate evidence of incision and erosion of the dike
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embankment toe by Halfmile Branch, which has contributed to some of the localized sloughing at
Areas 4, 5, 6, 7, and 8.
It is important to note that the Inactive Basins are presently forested (Figure 2) and do not contain
impounded surface water. Native soils within the HFLEE-125 Project Area consist of Kalmia
loamy sand, 0-2% slopes (KaA), and Leaf loam (Le) according to the Natural Resources
Conservation Service (MRCS) Wayne County soils data (Figure 4). The Inactive Basins at HF Lee
also contain coal combustion residuals (CCR).
The vegetative community within the proposed Project boundary is predominantly bottomland
hardwood forest dominated by overstory species such as red maple (Acer rubrum), sweetgum
(Liquidambar styraciflua), bald cypress (Taxodium distichum), willow oak (Quercus phellos) and
river birch (Betula nigra). Midstory and shrub layers consist of ironwood (Carpinus caroliniana),
wax myrtle (Myrica cerifera), and invasive Chinese privet (Ligustrum sinense); while the
herbaceous understory exhibits a predominance of rivercane (Arundinaria gigantea), greenbriers
(Smilax spp.), soft rush (Juncus effusus), and invasive Japanese stiltgrass (Microstegium
vimeneum). Additional information on existing conditions within the proposed Project boundary
is provided in AMEC Foster Wheeler (AMEC) Natural Resources Technical Report (Attachment
F).
JURISDICTIONAL FEATURES
At the request of Duke Energy, AMEC performed a wetlands and waters delineation within the
property boundary of the entire H.F. Lee Energy Complex in September — December 2014,
excluding the area within each basin. The complete delineation report and supporting
documentation, including illustration of jurisdictional features located within the H.F. Lee property
boundary, are provided in AMEC's report (Attachment F). The AMEC delineation identified
Halfmile Branch as a perennial stream and tributary to the Neuse River (Class WS -IV and NSW).
Within the Project Area, Halfmile Branch is located between the southern dike slope of Inactive
Basins 1 and 2 and Inactive Basin 3 (Figure 3). The AMEC delineation also identified a
bottomland forested fringe wetland between Halfmile Branch and its ephemeral side channel south
to the northern dike slope of Inactive Basin 3 (See Attachment B, Drawings 2 and 3 and
Attachment D within AMEC's report, Attachment F).
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During a site visit on 15 July 2014, Mr. David Vance (Geosyntec) performed a visual assessment
and delineation of the OHWM along the segment of Halfmile Branch located within the project
boundary. The delineated OHWM line was flagged and surveyed by a registered land surveyor
(Attachment B, Drawing 3). The design drawings depict the extent of streams and wetland features
identified within the boundary of the proposed HFLEE 125 Project by both Geosyntec (Halfmile
Branch OHWM only in Project Area) and AMEC (wetlands and streams around inactive basins).
The USACE conducted site visits on 03 March 2016, 07 July 2016, and 09 September 2016 to
verify the wetland and waters delineation.
PROPOSED JURISDICTIONAL IMPACTS
The proposed Project will require placement of new permanent stabilization material (boulder toe
and riprap protection) below the OHWM along 408 LF of the northern streambank of Halfmile
Branch (Attachment B, Drawings 6 and 7). The permanent stabilization material will be placed
below the OHWM at five areas: Area 4 (5 LF), Area 5 (100 LF), Area 6 (100 LF), Area 7 (90 LF),
and Area 8 (113 LF).
The Temporary Bypass Plan requires the temporary installation of four coffer dams, one upstream
of Area 4 (6 LF), one downstream stream of Area 7 (6 LF), one upstream of Area 8 (6 LF), and
one downstream of Area 8 (6 LF). All cofferdams will be hand -placed within Halfmile Branch.
The temporary impact associated with coffer dam placement is 24 LF.
Additionally, bank stabilization and embankment repairs (which constitute "protection of existing
structures" under NCDEQ riparian buffer protection rules) proposed for the south facing dike of
Inactive Basin 2 are considered "allowable" buffer encroachments [15A NCAC 02B .0233,
paragraph (6)] and do not require a NCDEQ Riparian Buffer Variance. The characterization of
the Project as an "allowable" use requires written authorization from DWR prior to conducting the
work. Written authorization is being requested from DWR through the USACE PCN submittal
and review process for both riparian buffer protection and Section 401 Water Quality Certification.
AVOIDANCE AND MINIMIZATION
Due to the observed bank failures (i.e., sloughing) along the perimeter dike of Inactive Basin 2,
avoidance of impacts to Halfmile Branch to stabilize the dike slope is not practicable. The repair
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of the dike slope is imperative to maintain the integrity of Inactive Basin 2 and to protect the water
quality of Halfmile Branch and the Neuse River. The proposed Project minimizes the permanent
dike slope/streambank stabilization -related footprint along Halfmile Branch to no more than
necessary for dike repair, totaling 408 LF of streambank. The proposed Project avoids permanent
impacts to an abutting bottomland hardwood forested wetland and south stream buffer
encroachment (Attachment B, Drawing 3; Referred to as Wetland HBG in AMEC report,
Attachment F). Duke Energy proposes to continue to monitor the remaining dike
slope/streambank of Halfmile Branch not included in this proposed stabilization project. Should
additional dike/streambank repairs be needed, these will be coordinated with the USACE and
NCDEQ at that time.
The Erosion and Sediment Control Plan (as shown in Attachment B, Drawings 4 through 8 and
10) is intended to minimize the risk of erosion and sediment related complications from proposed
stabilization activities. To further minimize the risk of erosion, work within the stream channel
will be conducted in the dry. Additional avoidance and minimization measures include the use of
coffer dams for prevention of sediment contact with stream flow during dewatering and
construction activities. Water collected within the construction area will be actively pumped (as
needed) into Inactive Basin 2 (no outlet) during and at completion of stabilization activities to
avoid introduction of sediment into natural channel flow. Due to the potential for the Neuse River
to backwater into Halfmile Branch and the chance of storms in the Halfmile Branch watershed, all
construction equipment will be removed from the work areas at the end of each day. Additionally,
boulders and fabric formed articulating block mats will be installed immediately after the failed
soil mass has been removed and the area regraded to reduce potential erosion issues. Finally, all
areas affected by the proposed Project will be stabilized immediately following the completion of
work activities.
FLOODPLAIN COMPLIANCE
The proposed HFLEE 125 Project is located within the Federal Emergency Management Agency
(FEMA) -designated 100 -year floodplain (Figure 5; Attachment B, Drawing 2). Activities
associated with the proposed Project will be performed in compliance with federal and local
FEMA 100 -year floodplain requirements. The proposed Project does not include plans to
introduce above grade fill material into the floodplain.
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THREATENED AND ENDANGERED SPECIES
Geosyntec performed a desktop review of federally -listed species that are known to occur in
Wayne County, North Carolina. An official species list was obtained from the USFWS ECOS-
IPaC system on January 19, 2017. Geosyntec also evaluated the state rare species list provided by
the North Carolina Natural Heritage Program. Based on the desktop review, impacts to state- and
federal threatened and endangered species or critical habitat are not expected.
A review of the National Marine Fisheries Service (NMFS) Habitat Conservation website
indicated the proposed Project is not located in an area designated as Essential Fish Habitat. In
previous consultation with the Anadromous Fish Coordinator for North Carolina Wildlife
Resources Commission, Mr. Jeremy McCargo, was made in July 2015 for previous
dike/streambank repair. Mr. McCargo then stated the proposed Project has potential to impact
aquatic resources, but the impacts should be minimal if the project begins in August and is
concluded before the following February (documentation provided in Attachment G).
Postponing the repair work until this time frame poses undue risk on the integrity of the
streambank/dike repair. The Project has been designed to minimize impacts to the greatest extent
practicable, including reducing pump -around areas and bank repair to the minimum areas
necessary. Impacts to aquatic resources are not expected from this Project.
CULTURAL RESOURCES
Geosyntec performed a desktop review of the National Register of Historic Places database. Based
on this review and information from the North Carolina State Historic Preservation Office, the
proposed Project would not adversely affect any known historic properties included in or eligible
for inclusion in the National Register of Historic Places. The proposed Project does not occur in
or near an area with known cultural preservation status. Further, the proposed Project is located
at an existing facility and does not involve new development.
COMPENSATORY MITIGATION
The proposed streambank stabilization involves maintenance and protection of an existing dike
structure to maintain the integrity of the Inactive Basin 2 dike and the total permanent stabilization
footprint is less than an average of one (1) cubic yard per running foot along the bank below the
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OHWM. Additionally, the proposed work will not result in a loss of aquatic function and will
reduce downstream sedimentation of Halfmile Branch and the Neuse River. Therefore, Duke
Energy proposes that no compensatory mitigation is required.
CONCLUSION
Duke Energy proposes to perform vegetation management and dike slope and streambank
stabilization activities at the Inactive Basin 2's southern dike slope at H.F. Lee Energy Complex.
The proposed Project also includes removal of vegetation within the riparian buffer of each
stabilization area. Proposed stabilization activities include the permanent placement of boulder
toe protection (below OHWM) and fabric formed articulating block mats (stabilized dike slope
above OHWM) along 408 LF of the south -facing dike/streambank slope of Inactive Basin 2, which
is also the northern streambank of Halfmile Branch (a jurisdictional, perennial tributary to the
Neuse River). The Project will require stream buffer encroachment (exempt) to provide temporary
construction access to the dewatered channel (temporary) of Halfmile Branch during stabilization
activities. Additional construction measures will include the temporary placement of coffer dams
along a total length of 24 LF of Halfmile Branch.
Please see the attached PCN Form and supporting documentation for further details of the Project.
If you have any questions or need clarification regarding the information provided, feel free to
contact Robert Dunn at rdunnkgeosyntec.com or 678-202-9613 or David Vance, P.G. at
dvancena eosyntec.com or 678-202-9612 at your convenience.
Respectfully submitted,
Robert M. Dunn
Senior Staff Scientist
David J. Vance, P.G.
Senior Scientist
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Attachments: Figures
A. PCN Form
B. Inactive Basin 2 Perimeter Dike Slope Stabilization Project Design
Drawings
C. 2015 Bank Stabilization Project Authorizations
D. 2015 Bank Stabilization Project Design Drawings
E. Site Photographs
F. Natural Resources Technical Report by AMEC Foster Wheeler
G. Agency Consultation for Protected Species
Copies to: NCDEQ: Anthony Scarbraugh
Duke Energy: Steve Cahoon, Keith Gifford, Henry Hardy, Jr., Austin Mack,
Scott Updike, Don Gibbs, and Ken Karably
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