SW3220304_Response To Comments_20220629

(Z)
Colelenest&Stone
BOLTON & MENK,INC.
June 28, 2022
Mr. Jim Farkas
NCDEQ Division of Energy, Mineral & Land Resources
512 N. Salisbury Street, Office 640E
Raleigh, NC 27604
RE: 4773 —Aldi East Spencer In -bound Traffic Improvements
Stormwater Permit No. SW3220304
Dear Jim:
South Tryon Street, Suite 1400
Charlotte, NC 28202
Office: 704-376-1555
colejeneststone.com
The following responses are offered in connection with the permit review comment letter dated June 8, 2022, for the
referenced project:
Comment 1.a.i — Overland flow from parking area
The subject parking area has been re -graded to reduce the overland flow path to <150 LF.
Comment Lb — Pipe network around the proposed dispatch building
The pipe network has been eliminated in favor of a graded swale with culverts under the sidewalk areas and the roof
drain leaders are indicated to outlet to the swale where possible or tie to the sidewalk culvert where they directly
intersect.
Comment 1.c — Pipe network crossing the inbound traffic lanes
Additional side swales at the driveway fill slope have been added to direct as much flow away from the pipe network as
possible. The pipe network at the driveway low point is retained to convey drainage under the pavement and down the
adjacent fill slope to a stabilized outlet at the base of slope (Drainage Structures STCB-2 to HW-1). This drainage system
will collect approximately 4.2 acres of drainage area with an associated 10-year discharge of approximately 26.9 cfs.
Accordingly, a pipe is used to control the drainage and maintain stable slope conditions. Approximately 500 LF of
vegetated outfall swale exists beyond the toe of slope to the downstream discharge point at the property line.
Comment 1.d —Trench drain at loading dock
Comment acknowledged. The trench drain is retained.
Comment 2 —Surface water areas
Surface water areas and associated buffers have been noted on Sheet C-403. The surface water areas have been
deducted from the property area total for purposes of density calculations on the permit application and Supplement-
EZ form. Note that the pond area indicated on the USGS map no longer exists so has not been included in the surface
water deduction.
Comment 3 — Drainage areas
The drainage areas in Section IV 10 of the permit application have been converted to square feet.

Comment 4 — Manning s n-values
The Manning's n-value for all ditch calculations has been adjusted to 0.045, representative of a short grass lining.
Comment 5 — Supplement-EZ Form
Corrections to the Supplement-EZ Form have been made as indicated.
Respectfully submitted,
R. Todd Fisher, PE
Director of Civil Engineering
00000.00 1 June 28, 2022