SW6221007_Response To Comments_20230124

HILLIARD
E.NGIN EI ING
PO Box 249, Sanford, NC 27331
[phone]
To: TRANSMITTAL
Division of Energy, Mineral & Land Resources
Stormwater Program
Att: Jim Farkas
1612 Mail Service Center
512 N. Salisbury Street
Raleigh, NC 27699-1612
Date: 01/24/23
Project: Spout Springs Self Storage and Miracle Movers Warehouse
HE#: HC2215
Please find enclosed the following:
One (1)
Original
Updated Supplement EZ form
One (1)
Copy
Updated. Sealed, signed and dated calculations sheets to include stage -storage and area/volume calcE
Two (2)
Copies
Updated Sheet C4.4
The enclosed revisions are submitted for approval pursuant to your January 23, 2023 letter with comments.
1. a. A stage -storage table has been provided for the main pool and the forebay.
1.b. Calculations showing how MDF 1 & 2 are being met are enclosed: The Stage -Storage calcs & Surface Area and Depth Required
2.a. See revised supplement EZ with adjustments to surface area and volumes. Sediment storage is 1' deep from 380 to 381 and is not
part of the computed volume.
2.b. The elevation of the Gabion walls 1' above the permanent pool elevation has been noted on the plans for the baffle section
so that the pond will not short circuit.
3.a. A table reflecting pond elevations has been added to Sheet C4.4. A note regarding the forebay entrance being 6" lower than the
forebay exit has also been added.
3.b. The forebay entrance and exit elevation has been added to Sheet C4.4 in the cross section.
3.c. The 10:1 slope of vegetation shelf was a typo and has been revised to be 6:1.
4.a. The closest surface waters are off site and the total length of the vegetation setback has been revised on the Supplement.
`4.b.i.1 The drainage area item was addressed in the administrative review from comments received 10/21/22; resubmitted 10/21/23.
4.b.1.2 The percent impervious has been revised in the Supplement. Revised Supplement is attached.
14.b.i.3. These items were deleted from the column
4.b.1_4 The entire site column has been revised to reflect existing on site buildings and drainage area for entire property.
4.b.ii.1 The drainage area should be 563,231 sf and has been revised on the enclosed supplement.
4.b.ii.2 The value in the WQv has been revised to match the Drainage Area column
5. PDFS were uploaded to the website. Hard copies are enclosed with the mailed submittal of this transmittal.
Thank you for your review of this project.
Please let me know if you have any questions or need any additional information.
Jarrod E. Hilliard, PE, CFM
Hilliard Engineering, PLLC