M-0540A_MinorModRequest_20221011

STATE OF NORTH CAROLINA
DEPARTMENT OF TRANSPORTATION
ROY COOPER J.ERIC BOYETTE
GOVERNOR SECRETARY
Mailing Address:
NC DEPARTMENT OF TRANSPORTATION
DIVISION OF HIGHWAYS
5501 BARBADOS BOULEVARD
CASTLE HAYNE, NC 28429-5647
Telephone: [phone]
Fax: [phone]
Customer Service: 1-877-368-4968
Website: ncdot.gov
Location:
5501 BARBADOS BOULEVARD
CASTLE HAYNE, NC 28429-5647
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October 12, 2022
Mr. Stephen Lane
Coastal Management Representative, Transportation Projects
Division of Coastal Management
400 Commerce Ave.
Morehead City, NC 28557
Subject: Minor Modification Request for Alternate Work Trestle Design CAMA Major
Permit No. 78-22, TIP No. M-0540A NC 24 Resiliency and Living Shoreline Project
WBS No. 49083.3.1
Dear Mr. Lane,
The N.C. Department of Transportation, Division 3 Highway Unit is requesting a minor
modification for an alternate temporary work trestle design as proposed by the contractor in
the enclosed submittal for the construction of the M-0540A NC 24 Living Shoreline. The
proposed alternate trestle design would be constructed within the same footprint as the
existing approved trestle and would not exceed the currently authorized permanent impact
area.
The alternate trestle design would eliminate the use of piles at the trestle bents and instead
proposes the use of 4’ x 20’ logging mats to be stacked as the supporting trestle bents to
maintain the minimum low chord 2’ above normal high water. Eliminating the use of pipe
piles from the from the trestle design eliminates the approx.1 cu. yd. of substrate per pile
that is typically displaced during pile extraction. Approximately 70 piles would be required
for the construction of the trestle as currently authorized. The proposed alternate design
would prevent the need to fill in voids in the substrate typically left by pipe piles. The
elimination of the piles also eliminates the vibration associated with pile driving and
reduces the heavy equipment required for construction by eliminating the need for a crane
and vibratory hammer.
An additional benefit of the proposed alternate trestle design is that it would reduce the
overall in-water work construction timeline from approx. 18 weeks with a pile drive trestle

2

Mailing Address:
NC DEPARTMENT OF TRANSPORTATION
DIVISION OF HIGHWAYS
5501 BARBADOS BOULEVARD
CASTLE HAYNE, NC 28429-5647
Telephone: [phone]
Fax: [phone]
Customer Service: 1-877-368-4968

Website: ncdot.gov
Location:
5501 BARBADOS BOULEVARD
CASTLE HAYNE, NC 28429-5647

to approx. 12 weeks. The quicker construction and increased mobility of the proposed
system would allow for faster deconstruction in the event of severe weather forecasts.

Using the logging mats as trestle bents would not significantly increase the weight per
square foot that is currently proposed by the authorized marine sand backfill. As noted on
the enclosed work trestle plan submitted by the contractor, the sills will be constructed in
their entirety prior to placing any of the proposed backfill in an effort to minimize losses of
material.

Included in this submittal is information and photos provided by the project contractor,
T.A. Loving Co., on their previous used of a logging mat system in constructing the Living
Shoreline for Carteret Community College (CCC) in Morehead City, N.C.. The system was
utilized from October 2021 to May 2021 and did not suffer any failures due to tides or
weather and resulted in no observable impacts to the environment. The N.C. Coastal
Federation has also acknowledged the success of this system in constructing the CCC
project and has vocalized their support for the proposed alternate trestle design.

The Division understands that a minor modification processing fee of $100.00 will be
applied the subject WBS. Please let me know if I can provide any additional information.

Sincerely,

Sean Farrell
NCDOT Division 3 Environmental Officer
[phone]
[e-mail]

ec:
Tom Steffens, USACE
Hannah Sprinkle, NCDWR