20120683 Ver 1_401 Application_20120712

C21 Progress Energy
July 10 2012
20120683
Mr Ian McMillan 401 Coordinator a
NC DWQ, 401 /Wetlands Unit
1650 Mail Service Center'
Raleigh NC 27699 1650
Subject Proposed Progress Energy Carolinas Milburme Person 230kV Overhead Electric
Transmission Line
Streambank Stabilization Project to Protect Tower
Dear Mr McMillan
Progress Energy Carolinas (PEC) is proposing to stabilize structure 268, a double circuit steel
lattice tower supporting the Milburme — Person & Falls — Milburme 230kV lines, located in
Raleigh, NC off of Wallingford Drive (See attachment 3— Engineenng Drawings) The adjacent
stream channel has moved eroding the bank and exposing one of the tower leg foundations The
purpose of this project is to develop a permanent solution to prevent any further erosion at the
structure and stabilize its foundation as well as stabilizing the streambank
PEC plans to mitiate work in mid September of 2012 and complete construction in
approximately 30 days
As proposed the project will impact 173 linear feet of stream bank and result in 0 24 acre of
land disturbance There are no wetlands impacted by this project
PEC intends to permit this protect under Nationwide Permit 13 and General Certification 3885
for the 401 Water Quality Certification
The bank stabilization will take place in the Neuse River Basin and thus Neuse Buffer rules
apply Bank stabilization is an allowable practice (as defined by 15A NCAC 02B 0233(7)(b))
thus it requires a no practical alternatives analysis The bank stabilization described herein has
no practical alternatives as described in the attached PCN (See attachment 2)
Overview U
►UL 1 2 2012 I
The proposed stream bank stabilization consists of three parts First gablon b sl � a
container filled with stone) will be used to harden the stream bank around the existing ran erai e
line Structure 268 The design includes approximately 63 linear feet of gabion wall The typical wall
section includes one (1) 4 5 x 3' x 9' basket and one (1) 3' x 3' x 9' basket (rows stacked two
Progress Energy Carolinas Inc
P 0 Box 1551
Raleigh NC 27602

baskets high) The base elevation of the baskets will be 252 5 (approximately 1 below the bottom of
the stream bed)
A preliminary geotechnical investigation was performed prior to design The geotechnical
investigation indicated material below the stream bed is not suitable for a base underneath the gabion
baskets Therefore removal (undercutting) of the in situ material will be required and bridging will
be added to provide a suitable base for the baskets The undercut will be to 2 feet below the bottom
of the basket approximate elevation of 250 5 The undercut shall also extend horizontally beyond
the basket width one foot for every one foot of depth Therefore the total undercut shall be
approximately 8 5 feet wide
The proposed bridging material includes lining the undercut area with 4 5 ounce non woven
separation geotextile fabric then Tensar BX 1200 Biaxial Geogrid then ABC stone (2 feet deep
placed in 12 inch lifts) The stone shall be compacted to 98% Maximum Standard Proctor (ASTM
698) The remaining areas shall be filled with suitable backfll and compacted to 95% Maximum
Standard Proctor (ASTM 698)
Second there is a large root mass on the stream bank opposite of Structure 268 that is blocking
stream flow and causing turbulent water conditions This impeded stream flow is the most likely
cause of the erosion For this reason the root mass will be removed and the area will be re graded and
stabilized with Class B rip rap The rip rap will be placed on geotextile fabric plus a six inch layer of
crushed stone below the rip rap Special care will be taken to smooth the rip rap into the stream bank
at the edges to ensure there is no undercutting from the flow in the stream
Third a permanent stormwater diversion channel has been designed to divert upland stormwater
runoff around the existing structure to prevent future erosion at the base of the tower Permanent
check dams will be included in the construction to reduce water velocity in the channel The last 15
of the channel will be lined with Class B rip rap and constructed to provide a smooth transition to the
rip rap bank stabilization to avoid undercutting All Class B rip rap will be a minimum of 18 inches
thick This work is entirely in an upland area
This work will require dewatering the stream segment temporarily for construction operations The
work area will be limited to a length which can be completed in one day Pump around details have
been provided The pump will discharge to a stable velocity dissipater made of rip rap or sandbags
General Erosion Control Measures
While the extent of the project does not require approval of an erosion control plan PEC will limit
impacts to the extent possible
Work crews will take all necessary precautions to prevent any erosion of the banks or adjacent land
or access into the right of way Permanent groundcover shall be provided where soil is exposed
during the construction process within 14 days of disturbance

A temporary construction entrance is included as well as temporary silt fence around grading
operations Some clearing will be required on the eastern bank to properly remove the root mass and
re grade the bank
Should you or others have any questions or wish to visit this project please contact Mr Dalton Cook
in the Environmental Services and Strategy Unit at 919 546 4396 (office) or
dalton cook @pgnmail com (e mail)
Thank you for your consideration
Sincerely
-2�eli
Richard A Brown
General Manager —
Transmission Construction and Engineering
CA/cdc
Enclosures
1 $570 Check for Permit Review Fee
2 Preconstruction Notification
3 Engineering Drawings
4 Engineering Calculations
5 Images of Bank Erosion and Structure
Cc USACOE — Raleigh Regulatory Field Office
Mr Dalton Cook
Ms Jada Whitley

q�ot W ATE19
o <
20120683
Office Use Only
Corps action ID no
DWQ project no
Form Version 1 3 Dec 10 2008
- -'~w,"waiv finch
Page 1 of 12
PCN Form — Version 1 3 December 10 2008 Version
Pre - Construction Notification PC Form
A Applicant Information
1
Processing
1a
Type(s) of approval sought from the
Corps
Section 404 Permit ❑Section 10 Permit
1 b Specify Nationwide Permit (NWP) number 13 or General Permit (GP) number
1 c
Has the NWP or GP number been verified by the Corpse
® 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
❑ 401 Water Quality Certification — Express ® Riparian Buffer Authorization
1 e
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
1g
Is the project located in any of NC s twenty coastal counties If yes answer 1h
below
❑ Yes ® No
1h
Is the project located within a NC DCM Area of Environmental Concern (AEC)?
❑ Yes ® No
2
Project Information
2a
Name of project
Progress Energy Carolinas Mdburne Person 230 kV Transmission Line
2b
County
Wake
2c
Nearest municipality / town
Raleigh
2d
Subdivision name
2e
NCDOT only T I P or state
project no
3
Owner Information
3a
Name(s) on Recorded Deed
Carolina Power & Light Co d /b /a Progress Energy Carolinas
3b
Deed Book and Page No
Linear electric utility with perpetual easements from underlying property owners
3c
Responsible Party (for LLC if
applicable)
Richard A Brown General Manager Transmission Construction & Engineering
3d
Street address
410 S Wilmington St D
3e
City state zip
Raleigh NC 27601
3f
Telephone no
919 546 3122
3g
Fax no
919 546 7552
3h
Email address
richard brown @pgnmad com Wye -d WA7.ER
- -'~w,"waiv finch
Page 1 of 12
PCN Form — Version 1 3 December 10 2008 Version

4
Applicant Information (if different from owner)
4a
Applicant is
❑ Agent ❑ Other specify
4b
Name
4c
Business name
(if applicable)
4d
Street address
4e
City state zip
4f
Telephone no
4g
Fax no
4h
Email address
5
AgentlConsultant Information (if applicable)
5a
Name
Dalton Cook
5b
Business name
(if applicable)
Progress Energy Carolinas Environmental Permitting and Compliance
5c
Street address
410 S Wilmington St
5d
City state zip
Raleigh NC 27601
5e
Telephone no
919 546 4396
5f
Fax no
919 546 6386
5g
Email address
dalton cook @pgnmad com
Page 2 of 12
PCN Form — Version 1 3 December 10 2008 Version

B
Project Information and Prior Project History
1
Property Identification
1a
Property identification no (tax PIN or parcel ID)
1726747706
lb
Site coordinates (in decimal degrees)
Latitude 35 85007 Longitude 7856898
(DD DDDDDD) (DD DDDDDD)
1c
Property size
2 62 acres
2
Surface Waters
2a
Name of nearest body of water (stream river etc) to
proposed project
Unnamed Tributary to Beaverdam Creek
2b
Water Quality Classification of nearest receiving water
Class C NSW
2c
River basin
Neuse River
Page 3 of 12
PCN Form — Version 1 3 December 10 2008 Version

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
The site is an existing grassed electric utility right of way in a residential neighborhood in North Raleigh The right of way
is used by work crews to access pole towers for periodic maintenance and to control vegetative growth to ensure electric
reliability
3b
List the total estimated acreage of all existing wetlands on the property
0 acres
3c
List the total estimated linear feet of all existing streams (intermittent and perennial) on the property
240 feet
3d
Explain the purpose of the proposed project
The purpose of the project is to stabilize a transmission line steel lattice tower footing that has been eroded by an
adjacent stream
3e
Describe the overall project in detail including the type of equipment to be used
The proposed stream bank stabilization consists of three parts First gabion baskets (wire fabric container filled with
stone) will be used to harden the stream bank around the existing transmission line Structure 268 The design includes
approximately 63 linear feet of gabion wall The typical wall section includes one (1) 4 5 x 3 x 9 basket and one (1) 3 x
3 x 9 basket (rows stacked two baskets high) The base elevation of the baskets will be 252 5 (approximately 1 below
the bottom of the stream bed)
A preliminary geotechnical investigation was performed prior to design The geotechnical investigation indicated material
below the stream bed is not suitable for a base underneath the gabion baskets Therefore removal (undercutting) of the
in situ material will be required and bridging will be added to provide a suitable base for the baskets The undercut will be
to 2 feet below the bottom of the basket approximate elevation of 250 5 The undercut shall also extend horizontally
beyond the basket width one foot for every one foot of depth Therefore the total undercut shall be approximately 8 5 feet
wide
The proposed bridging material includes lining the undercut area with 4 5 ounce non woven separation geotextde fabric
then Tensar BX 1200 Biaxial Geogrd then ABC stone (2 feet deep placed in 12 inch lifts) The stone shall be compacted
to 98% Maximum Standard Proctor (ASTM 698) The remaining areas shall be filled with suitable backfill and compacted
to 95% Maximum Standard Proctor (ASTM 698)
Second there is a large root mass on the stream bank opposite of Structure 268 that is blocking stream flow and causing
turbulent water conditions This impeded stream flow is the most likely cause of the erosion For this reason the root
mass will be removed and the area will be re graded and stabilized with Class B rip rap The rip rap will be placed on
geotextde fabric plus a six inch layer of crushed stone below the rip rap Special care will be taken to smooth the rip rap
into the stream bank at the edges to ensure there is no undercutting from the flow in the stream
Third a permanent stormwater diversion channel has been designed to divert upland stormwater runoff around the
existing structure to prevent future erosion at the base of the tower Permanent check dams will be included in the
construction to reduce water velocity in the channel The last 15 of the channel will be lined with Class B np rap and
constructed to provide a smooth transition to the rip rap bank stabilization to avoid undercutting All Class B rip rap will be
a minimum of 18 inches thick This work is entirely in an upland area
This work will require dewatering the stream segment temporarily for construction operations The work area will be
limited to a length which can be completed in one day Pump around details have been provided The pump will
discharge to a stable velocity dissipater made of rip rap or sandbags
Page 4 of 12
PCN Form —Version 1 3 December 10 2008 Version

4
Jurisdictional Determinations
4a
Have jurisdictional wetland or stream determinations by the
Corps or State been requested or obtained for this property /
El Yes ® No El Unknown
project (including all prior phases) in the past '
Comments
4b
If the Corps made the jurisdictional determination what type
❑ preliminary ❑ Final
of determination was made?
4c
If yes who delineated the jurisdictional areas?
Agency /Consultant Company
Name (if known)
Other
4d
If yes list the dates of the Corps jurisdictional determinations or State determinations and attach documentation
6
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
6
Future Project Plans
6a
Is this a phased project?
❑ Yes ® No
6b
If yes explain
Page 5 of 12
PCN Form — Version 1 3 December 10 2008 Version

C Proposed Impacts Inventory
1 Impacts Summary
la Which sections were completed below for your project (check all that apply)
❑ Wetlands ® Streams tributaries ® 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
2b
2c
2d
2e
2f
Wetland impact
Type of jurisdiction
number —
Type of impact
Type of wetland
Forested
(Corps 404 10
Area of impact
Permanent (P) or
(if known)
DWQ — non -404 other)
(acres)
Temporary
W1 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W2 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W3 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W4 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W5 ❑ P ❑ T
❑ Yes
❑ Corps
❑ No
❑ DWQ
W6 ❑ P [:IT
❑ Yes
❑ Corps
❑ No
❑ DWQ
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
3b
3c
3d
3e
3f
3g
Stream impact
Type of impact
Stream name
Perennial
Type of jurisdiction
Average
Impact
number
(PER) or
(Corps 404 10
stream
length
Permanent (P) or
intermittent
DWQ — non -404
width
(linear
Temporary (T)
(INT)?
other)
(feet)
feet)
S1 ®P ❑ T
Streambank
Unnamed
tributary to
® PER
❑ Corps
9
173
stabdiation
Beaverdam Creek
❑INT
®DWQ
S2 ❑ P [IT
❑ PER
❑ Corps
❑ INT
❑ DWQ
S3 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
S4 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
S5 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
S6 ❑ P ❑ T
❑ PER
❑ Corps
❑ INT
❑ DWQ
3h Total stream and tributary impacts
173
31 Comments Proposed project would utilize a minimal amount of nprap and gabion baskets in the streambanks to prevent
erosion around the tower base and to stabdze the streambank itself
Page 6 of 12
PCN Form — Version 1 3 December 10 2008 Version

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 individually list all open water impacts below
4a
Open water
impact number
— Permanent
(P) or
Temporary
4b
Name of waterbody
(if applicable)
4c
Type of impact
4d
Waterbody type
4e
Area of impact (acres)
01 ❑P ❑T
02 ❑P ❑T
03 ❑P ❑T
04 ❑P ❑T
4f Total open water impacts
4g Comments
5 Pond or Lake Construction
If pond or lake construction proposed then com lete 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
Flooded
P1
P2
5f Total
5g Comments
5h Is a dam high hazard permit required
❑ Yes 0 N If yes permit ID no
51 Expected pond surface area (acres)
5j Size of pond watershed (acres)
5k Method of construction
Page 7 of 12
PCN Form — Version 1 3 December 10 2008 Version

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 you MUST fill out Section D of this form
6a
® Neuse ❑ Tar Pamlico ❑ Other
Project is in which protected basin?
❑ Catawba ❑ Randleman
6b
6c
6d
6e
6f
6g
Buffer impact
number —
Reason for
Buffer
Zone 1 impact
Zone 2 impact
Permanent (P)
impact
Stream name
mitigation
(square feet)
(square feet)
or Temporary
required?
131 ®P ❑ T
Streambank
Unnamed tributary to the
❑ Yes
225
stablization
Beaverdam Creek
® No
B2 ❑ P ❑ T
❑ Yes
❑ No
63 ❑P ❑T
❑Yes
El No
6h Total buffer impacts
61 Comments Proposed project would utilize a minimal amount of riprap in the buffer zone to stabilze the lower portion of the
diversion channel to prevent erosion of the tower base and the channel itself
D Impact Justification and Mitigation
7 Avoidance and Minimization
1 a Specifically describe measures taken to avoid or minimize the proposed impacts in designing project
The project was designed to disturb the minimal amount of streambank in order to achieve the desired amount of bank
reinforcement and erosion prevention
1 b Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques
While the extent of the project does not require approval of an erosion control plan PEC will limit impacts to the extent
possible Work crews will take all necessary precautions to prevent any erosion of the banks or adjacent land or access into
the right of way Permanent groundcover shall be provided where sod is exposed during the construction process within 14
days of disturbance A temporary construction entrance is included as well as temporary silt fence around grading operations
2 Compensatory Mitigation for Impacts to Waters of the U S or Waters of the State
2a Does the project require Compensatory Mitigation for
❑ Yes ® No
impacts to Waters of the U S or Waters of the State?
2b If yes mitigation is required by (check all that apply)
❑ DWQ ❑ Corps
❑ Mitigation bank
2c If yes which mitigation option will be used for this project?
❑ 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)
TType
Quantity
Page 8 of 12
PCN Form — Version 1 3 December 10 2008 Version

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
❑ warm ❑ cool ❑cold
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
6 Complete if Using a Permittee Responsible Mitigation Plan
5a If using a permittee responsible mitigation plan provide a description of the proposed mitigation plan
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
buffer mitigation?
❑ Yes ® No
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
Zone
6c
Reason for impact
6d
Total impact
(square feet)
Multiplier
6e
Required mitigation
(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
Page 9 of 12
PCN Form — Version 1 3 December 10 2008 Version

E
Stormwater Management and Diffuse Flow Plan (required by DWQ)
1
Diffuse Flow Plan
1 a
Does the project include or is it adjacent to protected riparian buffers identified
® Yes ❑ No
within one of the NC Riparian Buffer Protection Rules?
lb
If yes then is a diffuse flow plan included? If no explain why
®Yes No
❑
Comments
2
Stormwater Management Plan
2a
What is the overall percent imperviousness of this project?
0 197 %
2b
Does this project require a Stormwater Management Plan?
❑ Yes ® No
2c
If this project DOES NOT require a Stormwater Management Plan explain why Proposed project adds a negligible
amount of impervious surface
2d
If this project DOES require a Stormwater Management Plan then provide a brief narrative description of the plan
❑ Certified Local Government
2e
Who will be responsible for the review of the Stormwater Management Plan?
❑ DWQ Stormwater Program
❑ DWQ 401 Unit
3
Certified Local Government Stormwater Review
3a
In which local government s jurisdiction is this project?
Wake County
❑ Phase II
3b
Which of the following locally implemented stormwater management programs
® NSW
❑ USMP
apply (check all that apply)
❑ Water Supply Watershed
❑ Other
3c
Has the approved Stormwater Management Plan with proof of approval been
❑ Yes ® No
attached
4
DWQ Stormwater Program Review
❑ Coastal counties
4a
Which of the following state implemented stormwater management programs apply
❑ HQW
❑ ORW
(check all that apply)
❑ Session Law 2006 246
® Other N/A
4b
Has the approved Stormwater Management Plan with proof of approval been
attached?
❑ Yes ® No
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 10 of 12
PCN Form — Version 1 3 December 10 2008 Version

F
Supplementary Information
1
Environmental Documentation (DWQ Requirement)
la
Does the project involve an expenditure of public (federal /state/local) funds or the
❑ Yes
® No
use of public (federal /state) land?
lb
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 213 0200)?
2b
Is this an after the fact permit application?
❑ 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
No wastewater will be generated
Page 11 of 12
PCN Form — Version 1 3 December 10 2008 Version

5 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?
❑ Raleigh
5c If yes indicate the USFWS Field Office you have contacted
❑ Asheville
5d What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical
Habitat?
Environmental Services Inc of Raleigh NC
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?
Environmental Services Inc of Raleigh NC
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?
Environmental Services Inc of Raleigh NC
8 Flood Zone Designation (Corps Requirement)
8a Will this project occur in a FEMA designated 100 year floodplain?
F[-s ® No
8b If yes explain how project meets FEMA requirements
8c What source(s) did you use to make the floodplain determination? FEMA Flood Map Viewer
Richard A Brown
7 10 12
Applicant/Agents Printed Name
Date
Applic nt/A n ignature
(Agents signature is valid only if an authorization letter from the applicant
is provided
Page 12 of 12
PCN Form — Version 1 3 December 10 2008 Version

Permanent Channel 1
Project Progress Energy Wallingford
Location Wake County North Carolina
Objective Design channel to convey flow generated from the 10 year storm event in anon erosive manner
Ensure channel does not over top in the 100 year storm event
References (1) North Carolina Erosion and Sediment Control Planning and Design Manual
(2) Elements of Urban Stormwater Design H R Malcom
Procedure Use procedures outlined in the above reference Rational Method will be used
to calculate flows Normal depth will be calculated using Mammngs Equation and
water velocity will be calculated using the principle of continuity (Q = VA)
Channels will be designed to carry flow generated by the 10 Year storm event using maximum slope
Channels will be checked to ensure no overtopping using the 100 year storm event and minimum slope
Calculations
Rational Method Q = C I A
Where
Q = Flow (cfs)
C = Runoff Coefficient
I = Rainfall Intensity (in/hr)
A = Drainage Area (ac)
Find C value in Reference 2
Find Intensity for 10 year event in Reference 2
C= 041
1 0= 644 Use min allowed t = 10 min
Drainage area (A) (ac) = 0 50
Q (cfs) = 13202
Check channel for adequate depth and for need for armoring
ime 2 5 tt/s as maximum allowable velocity for bare e+
4 5 ft/s as maximum allowable velocity for grass lined
Design channel lining using tractive force procedure
Calculations will be done using Manning s Equation to find normal depth
and Continuity (Q =V A) to find velocity
Q (cfs) = 13
S .(fttft) = 015
B (ft) = 3
Calculate normal depth and velocity with bare earth as lining
From Ref 2 n — 0 02
Flow (cfs) = 1 32
normal depth (ft) = 0 08
velocity 1t1s = 5 09
Calculate normal depth and velocity with temp excelsior matting
until vegetation is established
From Ref 2 n = 0 028
Flow (cfs) = 14
normal depth (R) = 01
velocity R/s = 4 00
Calculate normal depth and velocity with grass
From Ref 2 n = 0 03
Flow (cfs) = 1 4
normal depth (R) = 0 1
velocity (ft 1s) = 3 79
Channel cross section

Install check dams (spaced 25 apart)
Check channel for adequate depth for the 100 year storm event
C= 041
1 uu = 7 28 Use mm allowed t = 5 min
Drainage area (A) (ac) = 0 50
0 (cfs) = 1 5
S.h Pit) = 015
Calculate normal depth with grass
From Ref 2 n = 0 03
Flow (cfs) = 1 5
normal depth (ft) = 0 11
velocity (f 1s) = 3 60
Since the normal depth is less than 1 foot the channel will contain
the flow
T =yds
y= 624
d =01
s =015
T = 0 9828
permissible shear
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