20140694 Ver 1_More Info Received_20140915

� DUKE
�, ENERGY,
Sep 12, 2014
Mr David E Bailey
Project Manager
US Army Corps of Engineers
CE- SAW -RG -R
3331 Heritage Trade Drive, Suite 105
Wake Forest, North Carolina 27587
RECEIVED
N C Dept of ENR
SEP 15 2014
Winston -Salem
Regional Office
RE- Response to Request for Additional Information
Duke Energy Dan River Steam Station, Eden, Rockingham Co., NC
36 -inch Culvert Plug Project
Pre - Construction Notification — Nationwide Permit 18
U S Army Corps of Engineers File SAW- 2014 -01477
Dear Mr Bailey.
410 S Wilmington St
Raleigh NC 27601
Duke Energy in consultation with AMEC Environment & Infrastructure,_lnc (AMEC) recently
submitted a Pre - Construction Notification (PCN) to your office for issuance of U S Army Corps
of Engineers (USAGE) Nationwide Permit (NWP) 18 for the above - referenced project You
responded in August 13, 20014 email correspondence to Mr Steve Cahoon, Duke Energy,
stating that you had reviewed the information in the PCN and attached plans, but additional
information /revision would need to be provided to the USACE for the application to be
considered complete You provided three bulleted comments /queries in your email
correspondence These comments are repeated below and are accompanied by a response
Comment No 1
Your current proposal results In inundation of Waters of the US, including both wetlands and
streams, occurring as indirect impacts to the proposed regulated activity However, we do not
consider dewatering via indefinite pumping sufficient reason to consider the impacts temporary
As such, as currently proposed, the project would result in permanent impacts to wetlands and
streams subject to Inundation (I e permanent conversion of Waters type - wetland and stream
to open water) One possible way to avoid permanent Impacts to Waters of the US and show
avoidance and minimization would be to route flow from the wetland /stream area via gravity
pipe or ditch to another Water of the US
Response
The dewatering activities (I e , pumping) would not be conducted indefinitely It Is anticipated
that the dewatering activities would be conducted between one to three years, but not likely
longer than five years The time period required for pumping provides for removal of the ash and
closure and restoration of the pond area following ash removal Furthermore, the total amount
of time that the pump would be operational would be approximately two weeks per year,
presuming average climatological conditions In the local region The pump may need to be run
a week more, or a week less, per year If local precipitation Is atypically higher or lower,
respectively It is anticipated that pumping would be conducted for a period of 30 total minutes

per day (base flow pumping) and less than 48 hours following a 25 -year recurrence interval rain
event under average climatological conditions The type of pump would be a CD150 by
Godwin, which is capable of pumping 2290 gallons of water per minute Quality control would
be provided by on -site Duke Energy personnel to provide assurances that the mechanical pump
is kept in good operating condition and that repairs are completed in a timely manner, if
required Pumping during rain events will be float controlled
The option, or alternative, to reroute flow from the wetland /stream area via gravity pipe or ditch
to another Water of the US was explored However, this option was determined to be
problematic based on the existing topography surrounding the wetland /stream area The
elevation increases from 510 to 528 feet or higher on both sides (range of 18 feet) in the
landscape surrounding the wetland /stream area Furthermore the distance to adjacent grade
that would drain by gravity is in excess of 1,500 feet horizontally As such, large amounts of cut
and /or fill would need to be completed to reconfigure topographic grades that would be suitable
to allow for gravity flow to be successful. Gravity flow via pipe or open channel would be a
desirable alternative to dewater the over - flooded wetland /stream area, however, the amount of
time, labor, and monetary expense that would be required to implement this plan would be
excessive, to the extent practicable
Comment No 2
Your current proposal would pump /re -route inundated water in the impact area to the secondary
ash basin, which is not a Water of the US It is possible that this action, if permanent, would
render the wetland /stream area in question as non - jurisdictional by severing its nexus with the
Dan River If this is the case, we would consider the entire wetland /stream complex in question
a loss of Waters of the US
Response
In the PCN package submitted to the USACE, it was stated that the "pumped flows will be
discharged to the active secondary ash basin and ultimately outfall to the Dan River through the
outfall structure at NPDES outfall 002" and "any water that is impounded will be removed within
72 hours via pumping to the secondary ash pond" A clarification of the proposed action is
presented as follows in response to this comment The inundated water (over - flooding) from the
wetland /stream area would be routed via mechanical pumping to a draw Just outside of the ash
basin dike which leads to a stream feature located on the northeast side of the secondary ash
basin This stream feature is a direct tributary to the Dan River, thereby providing a direct
hydrological connection between the wetland /stream area at the 36 -inch culvert structure and
the Dan River The inundated water would not be pumped into the secondary ash basin at all,
rather, it would be discharged into the aforementioned draw Just outside of the ash basin dike
The draw enters the stream feature located on the northeast side of the secondary ash basin
The original plan view in the PCN submittal package has been revised to depict the location of
the stream feature located on the northeast side of the secondary ash basin and the proposed
action to pump the inundated water from the wetland /stream area to the draw /stream A revised
description of the proposed action has been added to the revised PCN application as
Attachment A, as further clarification of the details of the project The revised PCN, plan view
and detail drawings are attached herein

Comment No 3
Please review the above information with respect to your PCN and offer a permanent solution to
handling the flow from Waters of the US resulting from plugging the 36 inch pipe If you instead
propose to fill in the wetland /stream complex, please note that you must justify these actions in
terms of avoidance and minimization as well as practicability of alternatives Note also that
wetland impacts > 01 acre will require compensatory mitigation per Nationwide Permit
Condition 23.
Response
Duke Energy proposes to route, via mechanical pumping, the inundated water (over - flooding)
from the wetland /stream area to a draw /stream feature located on the northeast side of the
secondary ash basin This stream discharges at NPDES outfall 002 at the Dan River No
dredging and /or filling of the wetland /stream area at the 36 -inch culvert location are proposed
under the proposed action Alternatives to the proposed action were explored, but all
determined to be impracticable due to engineering constraints and /or time, labor, and monetary
limitations The proposed action will include temporary impacts to a jurisdictional wetland of
0 0973 acre due to over - flooding and 0 001 acre from placement of a cofferdam The total
amount of temporary impacts to the wetland will be 0 0983 acre This impact area does not
exceed 01 acre, therefore, compensatory mitigation should not be required under NWP
Condition 23
Please do not hesitate to contact me if you have any questions regarding the above responses
to your request for additional information
Respectfully,
'110�
Steve Cahoon
Sr Environmental Specialist
Duke Energy Environmental Services Department
Enclosures
Cc Sue Homewood (NCDENR — DWR)

' oc�Lfo"F�vi�n rF�RO�
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
la
Type(s) of approval sought from the Corps
❑X Section 404 Permit ❑ Section 10 Permit
lb Specify Nationwide Permit (NWP) number NWP 18 or General Permit (GP) number
1 c
Has the NWP or GP number been verified by the Corps?
❑X Yes ❑ No
1 d
Type(s) of approval sought from the DWQ (check all that apply)
FX_1 401 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 ❑X No
For the record only for Corps Permit
❑ Yes 'NX 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 ❑X No
1g
Is the project located in any of NC's twenty coastal counties If yes, answer 1 h
below
❑ Yes X❑ No
1h
Is the project located within a NC DCM Area of Environmental Concern (AEC)?
❑ Yes X❑ No
2
Project Information
2a
Name of project
Duke Energy Carolinas, LLC - Dan River Steam Station 36 -inch Culvert Plug
2b
County
Rockingham
2c
Nearest municipality / town
Eden
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 Carolinas, LLC
3b
Deed Book and Page No
Deed Book 1411, Page Number 2100
3c
Responsible Party (for LLC if
applicable)
3d
Street address
900 S Edgewood Road
3e
City, state, zip
Eden, NC 27288
3f
Telephone no
(919) 546 -7457
3g
Fax no
(919) 546 -4409
3h
Email address
steve cahoon @duke- energy com
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
4c
Business name
(if applicable)
Duke Energy
4d
Street address
410 S Wilmington Street
4e
City, state, zip
Raleigh, NC 27601
4f
Telephone no
(919) 546 -7457
4g
Fax no
(919) 546 -4409
4h
Email address
steve cahoon @duke- energy corn
5
Agent/Consultant Information (if applicable)
5a
Name
Joshua Bell, PE (Senior Water Resources Engineer)
5b
Business name
(if applicable)
AMEC Environment & Infrastructure, Inc
5c
Street address
2801 Yorkmont Road, Suite 100
5d
City, state, zip
Charlotte, North Carolina 28208
5e
Telephone no
(704) 517 -2618
5f
Fax no
(704) 357 -8638
5g
Email address
bosh bell @amec com
Page 2 of 10

B.
Project Information and Prior Project History
1.
Property Identification
1a
Property identification no (tax PIN or parcel ID)
PIN 798908886870
1 b
Site coordinates (in decimal degrees)
Latitude 36 491626 Longitude 79 715941
1 c
Property size
1 31 acres
2
Surface Waters
2a
Name of nearest body of water to proposed project
Dan River
2b
Water Quality Classification of nearest receiving water
Dan River = C
2c
River basin
Roanoke River Basin / HUC 03010103
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
A potentially jurisdictional scrub /shrub wetland with an herbaceous component and a perennial stream occur within the project site General land use
in the vicinity of the project site includes power generation facilities (buildings, parking lots, etc ), ash ponds and ash fill areas, a rail service line,
maintained grassed areas, and shrub and brushland
3b
List the total estimated acreage of all existing wetlands on the property 0 11
3c
List the total estimated linear feet of all existing streams (intermittent and perennial) on the property 64 9
3d Explain the purpose of the proposed project
The purpose of the project is to plug an existing 36 -inch diameter reinforced concrete culvert to prevent water from flowing under the ash fill basin
3e Describe the overall project in detail, including the type of equipment to be used
The culvert will be plugged and inflows piped to a draw /stream on the NE side of the Secondary Ash Basin (outfall at Dan River), see Attachment A
4
Jurisdictional Determinations
4a
Have jurisdictional wetland or stream determinations by the
Corps or State been requested or obtained for this property /
project (including all riot phases) in the past?
❑ Yes ❑X No ❑ Unknown
Comments
4b
If the Corps made the jurisdictional determination, what type
of determination was made?
El Preliminary El Final
4c
If yes, who delineated the jurisdictional areas?
Name (if known)
Agency /Consultant Company
Other
4d
The
of Engineers
If yes, list the dates of the Corps jurisdictional determinations or State determinations and attach documentation
discharge end of the 36 -inch pipe was dosed in February/March 2014 Please see the attached email from David Shaffer of the U S Army Corps
indicating that the discharge end was above the OHWM and no permit was required for closure
5
Project History
5a
Have permits or certifications been requested or obtained for
this project (including all prior phases) in the past?
❑ Yes ❑X No ❑ Unknown
5b
If yes, explain in detail according to "help file" instructions
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
la Which sections were completed below for your project (check all that apply)
❑X Wetlands ❑X 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 impact
Type of wetland
Forested
Type of jurisdiction
Area of
number
Corps (404,10) or
impact
Permanent (P) or
DWQ (401, other)
(acres)
Temporary T
W1 T
Flooding
Seep
No
Corps
00973
W2 T
Fill
Seep
No
Corps
0 001
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
00983
2h Comments
Wetland impacts are temporary due to stormwater impoundment (flooding) and cofferdam placement (temporary fill) Any water that is impounded will
be removed within 72 hours via pumping to a draw /stream located on the northeast side of the Secondary Ash Basin Outfall is at the Dan River The
stormwater diversion will result in a temporary impoundment, based on 25 -year event runoff storage See the attached Plan View and Cross - Section
drawings for details Also see Attachment A Note In the above table, W1 and W2 occur within the same wetland system
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)
S1 T
Flooding
Unnamed Tributary
INT
Corps
1 5
61
S2 T
Fill
Unnamed Tributary
INT
Corps
1 5
39
S3
Choose one
S4
Choose one
S5
Choose one
S6
Choose one
3h Total stream and tributary impacts
649
31 Comments
Stream impacts are temporary due to stormwater impoundment (flooding) and cofferdam placement (temporary fill) Any water that is impounded will
be removed within 72 hours via pumping to a draw /stream located on the northeast side of the Secondary Ash Basin Outfall is at the Dan River The
stormwater diversion will result in a temporary impoundment, based on 25 -year event runoff storage See the attached Plan View and Cross - Section
drawings for details Also see Attachment A Note in the above table, S1 and S2 occur within the same stream reach
Page 4 of 10
PCN Form — Version 1 4 January 2009

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 indiv ualiy 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
02
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, then 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
Choose one
P2
Choose one
5f Total -
5g Comments
5h Is a dam high hazard permit required?
❑ Yes ❑ No If yes, permit ID no
51 Expected pond surface area (acres)
5j Size of pond watershed (acres)
5k Method of construction
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 Project is in which protected basin?
❑ 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
B1
Yes /No
B2
Yes /No
B3
Yes /No
B4
Yes /No
B5
Yes /No
B6
Yes /No
6h Total Buffer Impacts:
61 Comments
Page 5 of 10

D. Impact Justification and Mitigation
1. Avoidance and Minimization
la Specifically describe measures taken to avoid or minimize the proposed impacts in designing project
The protect has been designed to avoid permanent impacts to jurisdictional surface waters Avoidance measures in inserting the grout (plug) into the
36 -inch culvert opening will entail the use of best management practices and approved construction techniques Any water that is impounded will be
removed within 72 hours via pumping to the draw /stream located on the northeast side of Secondary Ash Basin The proposed action at this location
will result in minor temporary impacts to potentially jurisdictional surface waters
lb Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques
Impacts to jurisdictional surface waters will be avoided during construction by traversing uplands to access the site with construction machinery, i e ,
access for construction equipment and materials will be provided via adjacent maintained roadways Silt fences and other sediment and erosion
control best management practices will be utilized to avoid impacts to wetlands and streams through erosion and sedimentation
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 ❑ 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
El 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
buffer mitigation?
El 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
15
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 7 of 10

E
Stormwater Management and Diffuse Flow Plan (required by DWQ)
1.
Diffuse Flow Plan
la
Does the project include or is it adjacent to protected riparian buffers Identified
❑ Yes ❑X 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
❑ Yes ❑ No
2.
Stormwater Management Plan
2a
What is the overall percent Imperviousness of this project?
1
2b
Does this project require a Stormwater Management Plan?
❑ Yes ❑X No
2c
If this project DOES NOT require a Stormwater Management Plan, explain why
The project site meets the low density criteria as specified under DWR Water Quality Certification No 3890, 1 e , the project has a built upon area of
less than 1 % BMPs have also been designed to meet the requirements of Water Quality Certification No
3890 for low density development The
proposed
action will not add impervious area to the project As specified by Water Quality Certification No
3890, two copies of the DWR Low Density
Supplement Form are attached to this PCN application
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?
DWR 401 Unit
3.
Certified Local Government Stormwater Review
3a
In which local government's jurisdiction is this project?
N/A
❑ 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 ❑X 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)
❑Session Law 2006 -246
❑Other Low Density (WQC 3890)
4b
Has the approved Stormwater Management Plan with proof of approval been
❑ Yes ❑X 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?
❑X Yes ❑ No
Page 8 of 10
PCN Form — Version 1 4 January 2009

F. Supplementary Information
1
Environmental Documentation (DWQ Requirement)
la
Does the protect Involve an expenditure of public (federal /state /local) funds or the
❑ Yes
X❑ No
use of public (federal /state) land?
lb
If you answered "yes" to the above, does the protect 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
❑X No
or Riparian Buffer Rules (15A NCAC 2B 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 protect (based on past and reasonably anticipated future impacts) result In
❑ Yes
Q 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 protect, or available capacity of the subject facility
Should wastewater be generated from the grouting of the plug of the 36 -inch culvert, the wastewater will be pumped to the Secondary Ash Basin The
proposed action of grouting the plug will not generate additional wastewater once the plug is in place
Page 9 of 10
PCN Form — Version 1 4 January 2009

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 X No
habitat?
5b Have you checked with the USFWS concerning Endangered Species Act
0 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?
USFWS Information, Planning, and Conservation System (IPaC) interactive website and the North Carolina Natural Heritage Program (NCNHP)
Natural Heritage Database Search interactive website A copy of the IPaC database query results for this project is attached herein
6. Essential Fish Habitat (Corps Requirement)
6a Will this project occur in or near an area designated as essential fish habitat?
❑ Yes ❑X No
6b What data sources did you use to determine whether your site would impact Essential Fish Habitat?
NOAA National Marine Fisheries Service — online interactive software "Essential Fish Habitat Mapper v3 0"
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 ❑X 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 Department of Cultural Resources, State Historic Preservation Office (SHPO) interactive web site ( HPOWEB) A graphic exhibit of the
HPOWEB map query for the protect vicinity is attached herein
8 Flood Zone Designation (Corps Requirement)
8a Will this project occur in a FEMA- designated 100 -year floodplain?
❑ Yes ❑x No
8b If yes, explain how project meets FEMA requirements
8c What source(s) did you use to make the floodplain determination?
A graphic exhibit of the 100 -year floodplain for the project vicinity is attached herein Source FEMA/FIRM map numbers 3710798900J, 3710799900J,
and 3710709000J, dated July 3, 2007
S4eP�ewt
C(/. ���
Applicant/Agent's Printed Name
Date
""Applicant/Agent's Signature
(Agent's signature is valid only if an authorization
letter from the applicant is provided
Page 10 of 10

Attachment A
This project is to provide for the grouting of the existing 36 inch reinforced concrete pipe that
drains a 6 acre drainage area Just upstream of the existing Secondary Ash Basin at Dan River
Steam Station in Eden, North Carolina The impacts to the stream include the installation of the
cofferdam for the grout installation, and the temporary inundation of the wetlands following
storm events Calculations indicate that the wetland area can store the 25 -year storm event up
to elevation 515 9 feet without discharge Pumping capacity currently provided allows for the
temporarily impounded water to be drawn back down within 72 hours of the storm event
Pumped flows will be discharged to a draw Just outside of the ash basin dike The draw enters
a stream feature located on the northeast side of the Secondary Ash Basin The stream feature
enters the Dan River through the outfall structure at NPDES outfall 002
r

PROPOSED EXTENTS OF
TEMPORARY
COFFER DAM , 1 �• IMPOUNDMENT BASED ONfff AREA = 43 SF ! % - ;1 2SVEAR EVENT RUNOFF
STORAGE (EL. 518)
/i�•• I. /� \ ✓,. I (DEWATER BY PUMPING
WITHIN 72 HOURS OF RAIN
EXISTING 38 4NCH ` \ \ \_ /// r \ 1 • 1I I \ \ ' J / / �' _ / '!\
REINFORCED CONCRETE
.. /I // /� l ,/• .' DREDGCPRAAINING ASH
/ EXISTING STREAM
(APPROX 6 FT.)
_ EXISTING 36 -INCH
REINFORCED CONCRETE
EXISTING WETLANDS ��—
PIPE (RCP) CULVERT TO BE
(APPROX. 4,867 SO.FT.) J _ -
GROUTED. INFLOWS WILL BE
- - -- A PUMPED TO SECONDARY
PROJECT BOUNDARY
� L - -� ASH BASIN SHORT -TERM
�[ Dal C�lli—
11
JPROPOSED BYPASS PIPE
6 -INCH DIA LINE
SECONDARY ASH BASIN
/PRIMARY ASH BASIN
PROPOSED OUTFALL
�3
LOCATION- APRON '
/ / I
SIZED FOR STABILIZATION
J
LEGEND
EXTENTS OF TEMPORARY
IMPOUNDMENT
EXISTING STREAM
— —
WETLANDS
- --------
PROJECT BOUNDARY
DUKE
IMPACTED WETLAND
AREA
36 -INCH CULVERT PLUG
TEMPORARY COFFER
DAM
PROJECT NO:
6226 -14 -0004
. -:. ;.
UT I
TRB \ \ DAN RWER,\
� \\ � \\
\ \ 100 0 100 200 FT
CLIENT.
DNM BY:
JMB
PROJECT
DAN RIVER STEAM STATION
DATE:
SEPT. 11,2014
DUKE
DUKE ENERGY - CAROLINAS
36 -INCH CULVERT PLUG
CHICDBY:
xxx
PROJECT NO:
6226 -14 -0004
DATUM:
NAD99
ENERGY.
AMEC Environment &Infrastructure
2801 YORKMOT ROAD, SUITE 100
CHARLOTTE, NC 28208
amec'�
TITLE
DIVERSION ROUTE -PLAN VIEW
REV. NO.:
A
PROJECTION:
uTM Zone o
FIGURE No.
PHONE [phone], FAX [phone]
LICENSURE: NC ENG: F -1253 NC GEOLOGY: C -247
FIGURE 03
SCALE:
1" = 50'
C �Uw��(o�h EM�Doeumni��DanRlwr\ fip - C-O01 (2) - Sp. 12, 2014 1 27am - *hbM

DEFINITION
APRON
LABEL
DISCHARGE
PIPE LOCATION
A STRUCTURE DESIGNED TO CONTROL EROSION AT THE INLET OR OUTLET OF A CHANNEL OR
LA
(FT)
WP
(FT)
CONDUIT.
FL
C50
(IN)
[SAX.
(IN)
SECTI(
PURPOSE
0.5
20
TO PREVENT EROSION AT THE OUTLET OF A CHANNEL OR CONDUIT BY REDUCING THE VELOCITY
15
18
OF FLOW AND DISSIPATING THE ENERGY.
12
CONSTRUCTION SPECIFICATIONS
1.
ENSURE THAT THE SUBGRADE FOR THE FILTER AND RIPRAP FOLLOWS THE REQUIRED LINES AND
DID
GRADES SHOWN IN THE PLAN. COMPACT ANY FILL REQUIRED IN THE SUBGRADE TO THE
T
DENSITY OF THE SURROUNDING DISTURBED MATERIAL. LOW AREAS IN THE SUBGRADE ON
UNDISTURBED SOIL MAY ALSO BE FILLED BY INCREASING THE RIPRAP THICKNESS.
T`
2.
THE RIPRAP AND GRAVEL FILTER MUST CONFORM TO THE SPECIFIED GRADING LIMITS SHOWN ON
THE PLANS.
3.
FILTER CLOTH, WHEN USED, MUST MEET DESIGN REQUIREMENTS AND BE PROPERLY PROTECTED
FROM PUNCHING OR TEARING DURING INSTALLATION. REPAIR ANY DAMAGE BY REMOVING THE
RIPRAP AND PLACING ANOTHER PIECE OF FILTER CLOTH OVER THE DAMAGED AREA. ALL
CONNECTING JOINTS SHOULD OVERLAP A MINIMUM OF 1 FT. IF THE DAMAGE IS EXTENSIVE,
REPLACE THE ENTIRE FILTER CLOTH.
4.
RIPRAP MAY BE PLACED BY EQUIPMENT, BUT TAKE CARE TO AVOID DAMAGING THE FILTER.
5.
THE MINIMUM THICKNESS OF THE RIPRAP SHOULD BE 1.5 TIMES THE MAXIMUM STONE DIAMETER.
6.
RIPRAP MAY BE FIELD STONE OR ROUGH QUARRY STONE. IT SHOULD BE HARD, ANGULAR,
DID
HIGHLY WEATHER— RESISTANT AND WELL GRADED.
7.
CONSTRUCT THE APRON ON ZERO GRADE WITH NO OVERFALL AT THE END. MAKE THE TOP OF
THE RIPRAP AT THE DOWNSTREAM END LEVEL WITH THE RECEIVING AREA OR SLIGHTLY BELOW
IT.
8.
ENSURE THAT THE APRON IS PROPERLY ALIGNED WITH THE RECEIVING STEAM AND PREFERABLY
STRAIGHT THROUGHOUT ITS LENGTH. IF A CURVE IS NEEDED TO FIT SITE CONDITIONS, PLACE IN
THE UPPER SECTION OF THE APRON.
9.
IMMEDIATELY AFTER CONSTRUCTION, STABILIZE ALL DISTURBED AREAS WITH VEGETATION.
MAINTENANCE
INSPECT RIPRAP OUTLET STRUCTURES AFTER HEAVY RAINS TO SEE IF ANY EROSION AROUND OR
BELOW THE RIPRAP HAS TAKEN PLACE OR IF STONES HAVE BEEN DISLODGED. IMMEDIATELY
MAKE ALL NEEDED REPAIRS TO PREVENT FURTHER DAMAGE.
�•� DUKE
ENERGY
CLIENT
ROCK RIPRAP
d50 = VARIES
8 OZ /SY NON —WOVEN GEOTEXTILE
WA
-T
SUMMARY OF PROTECTION APRONS
APRON
LABEL
DISCHARGE
PIPE LOCATION
DP
(FT)
LA
(FT)
WP
(FT)
WA
(FT)
T
(IN)
C50
(IN)
[SAX.
(IN)
Al
36 —INCH BYPASS
0.5
20
4
15
18
8
12
DUKE ENERGY - CAROLINAS
AMEC Environment & Infrastructure
2801 YORKMONT ROAD, SUITE 100
CHARLOTTE, NC 28208
PHONE [phone]. FAX [phone]
LICENSURE: NC ENG: F -1253 NC GEOLOGY: C -247
C: \U— e\jo��\DonRlvr\ dwq – C-001 (5) – Sp. 12. 2014 1:25mn – *AbW
BY. PROJECT
JMB
BY:
XXX
DATUM:
NAD99
amec PROJECTION.
UTM Zone 0
SCALE:
DAN RIVER STEAM STATION
36 -INCH CULVERT PLUG
DETAILS
T
SEPT. 11, 2014
PROJECT NO:
6226 -14 -0004
REV. NO.
A
FIGURE No.
FIGURE 04