[External] RE_ U-5710A 60' RCP outlet protection

From:Steffens, Thomas A CIV USARMY CESAW (USA)
To:Sprinkle, Hannah H; Giles, Jon W
Cc:Jetton, Joseph C; Pratt, Joshua T; Gingrich, Sophia E; Dustin (LJB, Inc.), Christopher; Westphal, Anneliese;
Herndon, T. Mason
Subject:[External] RE: U-5710A 60" RCP outlet protection
Date:Monday, May 15, 2023 3:59:30 PM
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Jon,

Thank you for the detailed update and request for concurrence. I agree with
the proposed solution as detailed in your description below. I am also in
agreement with Hannah’s comments about documentation and observations
concerning the native soil deposition in the rip rap.

Tom Steffens

From: Sprinkle, Hannah H <[e-mail]>
Sent: Monday, May 15, 2023 7:37 AM
To: Giles, Jon W <[e-mail]>; Steffens, Thomas A CIV USARMY CESAW (USA)
<[e-mail]>
Cc: Jetton, Joseph C <[e-mail]>; Pratt, Joshua T <[e-mail]>; Gingrich, Sophia E
<[e-mail]>; Dustin (LJB, Inc.), Christopher <[e-mail]>; Westphal,
Anneliese <[e-mail]>; Herndon, T. Mason <[e-mail]>
Subject: [Non-DoD Source] RE: U-5710A 60' RCP outlet protection

Jon,

Thanks for keeping us in the loop and providing this detailed update. As we discussed in the field, I
agree with NCDOT’s proposal to install a 5’x10’x2’ riprap pad at the outlet of the 60”RCP.
The outlet can be covered with native material if you think the system will allow the soil to settle and
stay in place. Otherwise, I’m comfortable letting it silt in naturally. I don’t want the material to blow
out during the first major rain event.
Please document the conversation with Center Point, I want them fully prepared for the release of
water, it would also be helpful to have the staff on site to monitor the dike removal/water release.

Thank you,

Hannah

From: Giles, Jon W <[e-mail]>
Sent: Friday, May 12, 2023 8:27 AM
To: Sprinkle, Hannah H <[e-mail]>; Steffens, Thomas A CIV USARMY CESAW
(USA) <[e-mail]>
Cc: Jetton, Joseph C <[e-mail]>; Pratt, Joshua T <[e-mail]>; Gingrich, Sophia E
<[e-mail]>; Dustin (LJB, Inc.), Christopher <[e-mail]>; Westphal,
Anneliese <[e-mail]>; Herndon, T. Mason <[e-mail]>
Subject: U-5710A 60' RCP outlet protection
Importance: High

Hannah & Tom,

Happy Friday! Just a quick synopsis of the current situation on the project. NCDOT began
construction of the project prior to the adjacent landowner (Center Point) beginning their
development. Both entities are working in the same stream and both projects abut at this location.
Center Point is installing a bottomless culvert with the inlet approximately 20’ from the edge of
NCDOT PDE. Due to the need to work in the dry CenterPoint has taken over the bypass pumping and
has installed an earthen berm inside NCDOT’s PDE. Center Point has not been properly running their
bypass pumps and it is continually resulting in the NCDOT get flood around the outlet of the 60”
RCP. NCDOT needs to release this water and allow the stream to flow in orcer to complete their
work.

As discussed last week during the New Hanover ride thru, NCDOT’s perfered method to protect 60”
culvert from scour or undermining through potential head cutting from down stream construction.
NCDOT proposes install a 5’x10’x2’ riprap pad at the outlet of our 60”RCP. This would prevent any
unforeseen issues with head cutting that may occur due to Center Point’s contractor over excavating
their bottomless culvert located within 70’ of the 60”outlet. This lowered their invert which may
have a negative effect to our structure, leaving it perched. The top of proposed pad will be installed
at the same elevation as the outlet invert of 16.1’, at the outlet of the newly installed 60”culvert and
then either covered with native material of left uncovered to silt in naturally, please advise which is
your preference. I have attached a sketch of the proposed solution.

All work will be performed in the dry. The contractor shall notify the Resident Engineer prior to
completion of the work so the contractor for Center Point can be prepared for the temporary dike to
be removed and water released so the NCDOT contractor can complete their work without being
inundated with water.

If you have any questions, please feel free to contact me. The contracto would like to get moving on
the revision early next week. Please advise once you have had an opportunity to review and if you
are in concurrence with the proposed solution so I can le the resident engineer know and they can
release to contractor to complete the construction of the stream relocation and storm water
installation.

Sincerely,

Jon

Jon W. Giles Jr.
Division Environmental Officer – Division 3
North Carolina Department of Transportation

910 341 2040 Office
910-902-0244 Mobile
910 675 0143 Fax
[e-mail]

5501 Barbados Blvd.
Castle Hayne, NC 28429

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