R-3300B Northern Interchange Drainage Revision

From:Herndon, T. Mason
To:Shaver, Brad ; Sprinkle, Hannah H; Lane, Stephen
Cc:Farrell, Sean C; Westphal, Anneliese
Subject:R-3300B Northern Interchange Drainage Revision
Date:Thursday, June 16, 2022 3:41:02 PM
Attachments:image001.png
R3300B_Permit Drawing 119 &120_20220511.pdf
Good Afternoon,

Due to concerns raised by the owner of Parcels 89 & 91 (Andrews Mortuary), drainage at the northern interchange has been reevaluated and revised
by our hydraulic engineers. The proposed 36” RCP and outfall ditch at -Y32_SRS Sta21+59/-Y32 RPB1_PCC- Sta. 20+65 has been removed from the
plans. A 30” RCP has been added at Sta. -L1_Northern- Sta. 856+00. The screen shot below provides a visual of the revision. Essentially, this revision
will convey more drainage to the dry detention pond (inside the interchange loop on west side of US-17), thus reducing the amount of proposed
drainage that would drain directly into the Andrews Pond during a storm event. The drainage from the detention pond would exit a riser, then drain
to the Andrews pond. This revision does not increase impacts to jurisdictional resources and actually provides better treatment of stormwater runoff.

Removal of the outfall ditch RT of Y32 RPB1_PCC- Sta. 20+65 does eliminate the permitted impacts for the ditch and potentially eliminates the
anticipated drainage effect on the 0.37 acre wetland remanent. This wetland was hatched out on the previous permit drawings as a total take but in
discussions with Brad and review of merger notes and etc., there is no record that the agencies requested this 0.37 acre wetland remnant to be
permitted or shown as a total take. In the attached revised permit drawings, the impact hatching has been removed from this remanent wetland and
it is has now been labeled as “Potential Impact 0.37 Acres”. The Department is proposing to preserve this wetland and to visually monitor it with the
agencies during and post construction to determine if it retains jurisdictional status. Safety fence has already bee installed around this wetland to
prevent incidental impacts. If it does retain jurisdictional status the Department would like for the permitting agencies to consider offsetting the
mitigation requirements for the A-section with the mitigation that has already been obtained for impacts to this site.

Attached for your records are revised permit drawings 119 of 162 and 120 of 162 dated 5/11/2022. Please review the attached drawing and the
information above and let me know if you have any questions or if any additional correspondence is required from you agency for approval of this
revision.

Thank you!

Mason Herndon
Project Development Environmental Engineer
Division 3
NCDOT- Division of Highways

910-341-2036 office
910-604-0050 mobile
[e-mail]

5501 Barbados Blvd
Castle Hayne, NC 28429

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