20201908 Ver 1_PreFiling Email 30-Day Clock Reached Email_20210108

Strickland, Bev
From: [e-mail]
Sent: Friday, January 8, 2021 12:00 AM
To: [e-mail]
Cc: Goss, Stephanie
Subject: Pre -Filing Time Clock has been reached for Buckhorn Dam Modifications - 20201908
Ver 1
Attachments: DWR Pre -Filing Meeting Request Form.pdf
The North Carolina Division of Water Resources has received the Pre -Filing Meeting Request Form for Buckhorn Dam
Modifications that you submitted on 12/8/2020. The ID number for that project is 20201908, Version 1.
Your Pre -Filing Meeting Request has now reached the 30 calendar days' requirement and your application can now be
accepted.
When you submit your application please upload a copy of the attached document in this email.
This email was automatically generated by Laserfiche workflow. Please do not respond to this email address, as
responses are not monitored

ID#* 20201908 Version* 1
Regional Office* Raleigh Regional Office - [phone]
Reviewer List* Stephanie Goss
Pre -Filing Meeting Request submitted 12/8/2020
Contact Name *
Contact Email Address*
Project Name*
Project Owner*
Project County*
Owner Address:
Richard Harmon
[e-mail]
Buckhorn Dam Modifications
Duke Energy
Chatham
Street Address
864 South Edgewood Road
Address Line 2
aty
Eden
Fbstal / Zip Code
27288
Is this a transportation project?* r Yes r No
Type(s) of approval sought from the DWR:
W 401 Water Quality Certification - F 401 Water Quality Certification -
Regular Express
r- Individual Permit r- Modification
r- Shoreline Stabilization
Does this project have an existing project ID#?*
r Yes r No
State / Province / Region
NC
Country
United States
Do you know the name of the staff member you would like to request a meeting with?
Please give a brief project description below. *

On behalf of Duke Energy, Wood Environment & Infrastructure
Solutions, Inc. (Wood) is requesting your review of proposed dam
repairs (modifications) at the Buckhorn Lake Dam (State ID CHATH-
022), Cape Fear Steam Station, Chatham County, North CBased on
a 2017 evaluation performed by Wood (then Amec Foster Wheeler)
there were several conditions where the earthen embankment section
of the Buckhorn Lake Dam and the related East Abutment Wall failed
to meet the minimum criteria set forth in the Duke Energy Master
Programmatic Document. In response, in February 2020, Duke
Energy requested that Wood develop recommendations and a design
to improve the factor of safety (FOS) on the downstream slopes of
the embankment, as well as to lessen the lateral forces on the
Eastern Abutment Wall.
Based on the results of Wood's analyses, the crest of the dam
adjacent to the ogee is proposed to be lowered by approximately 3 to
4 feet from elevation 170 to 171 feet National Geodetic Vertical
Datum (NGVD) 88 to an elevation of 167 feet NGVD88. Wood notes
that this elevation is approximately 1 foot above the calculated 100-
year flood elevation of the Cape Fear River.
To achieve the proposed grades, the existing observation platform
(flat concrete platform with handrails adjacent to ogee section) will be
removed, along with the ashlar pavement. As the observation
platform appears to be founded on the ashlar surfacing, and extends
below the proposed crest elevation of 167 feet NGVD88 in the
immediate vicinity of the Eastern Abutment Wall, the crest of the dam
will need to be re-established after the demolition of the platform and
the ashlar surface is complete. Therefore, several rows of gabion
baskets filled with aggregate will be utilized to reach the proposed
crest elevation of 167 feet.
The lowered crest will extend northeast for a distance of
approximately 85 feet, at which point the grades will slope upward at
a grade of approximately 11 horizontal to 1 vertical (11 HA V) where it
will meet the existing crest near the toe access roadway at
approximately elevation 172 feet NGVD88. By lowering the crest to
the proposed elevation, the upstream slope of the affected area will
be flattened from 1.91-1:1V to 3.31-1:1V, while the downstream slopes
will be flattened from 1.91-1:1V to approximately 2.4H:1V. As the ashlar
surface will be removed in order to allow for the regrading to take
place, the regraded portion of the earthen embankment will be
resurfaced with North Carolina Department of Transportation
(NCDOT) Class 1 rip rap.
Temporary wetland impacts are expected on the upstream slope of
the dam where replacement of the ashlar surface with NCDOT Class
1 rip rap will be in close proximity to the wetlands at the toe of the
slope. The area of the temporary wetland impacts is expected to be
less than 100 square feet and is necessary to provide for access to
the work area and the installation of erosion and sediment control
measures.
arolina. The proposed work activities will entail a temporary impact of
less than 100 square feet to waters of the U.S. (WoTUS).
Please give a couple of dates you are available for a meeting.
1 /8/2021

Please attach the documentation you would like to have the meeting about.
USACE Ltr Request - signed w graphics
597.36KB
Buckhorn - 12072020 5.pdf
pdf only
By digitally signing below, I certify that I have read and understood that per the Federal Clean Water Act Section
401 Certification Rule the following statements:
• This form completes the requirement of the Pre -Filing Meeting Request in the Clean Water Act Section 401 Certification
Rule.
• I understand by signing this form that I cannot submit my application until 30 calendar days after this pre -filing
meeting request.
• I also understand that DWR is not required to respond or grant the meeting request.
Your project's thirty -day clock started upon receipt of this application. You will receive notification regarding meeting location
and time if a meeting is necessary. You will receive notification when the thirty -day clock has expired, and you can submit an
application.
Signature
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Submittal Date 12/8/2020