SW6221202_Add Info_20230306

Ft`STATE.
o.o>s O
ROY COOPER A
Governor
ELIZABETH S.BISER
Secretary
DOUGLAS R.ANSEL NORTH CAROLINA
Interim Director Environmental Quality
March 6, 2023
CSD Engineering
Attn: John F. Oglesby, PE
PO BOX 1250
Wendell, NC 27591
AND
Turtle Run, LLC
Attn: Guy Lampe, Jr., Manager/Vice President
PO BOX 608
Smithfield, NC 27577
Subject: Request for Additional Information
Stormwater Permit No. SW6221201
Ample Storage
Harnett County
Dear Mr. Oglesby and Mr. Lampe:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on December 6, 2023. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
1. The following items were noted with the Wet Pond design:
a. Please include the top elevation for the sediment storage zone for the main pool and
forebay in the cross-sectional view of the wet pond. Per the information provided in
the other submittal items, the top of the sediment storage zone in the main pool
appears to be 185.0' (per Line 21 of the Wet Pond Page of the Supplement-EZ Form),
but it is not shown. NOTE: A minimum of 6" of sediment storage must be provided
in the main pool and forebay. NOTE: Storage volume provided in the sediment
storage zone does not contribute to the provided volume of the main pool or forebay.
Please revise the main pool and forebay volume calculations as needed.
b. Please ensure that the forebay entrance is deeper than the forebay exit (Wet Pond
MDC 5b). The entrance and exit elevations should be indicated on the cross-sectional
view. NOTE: A minimum of 6" of sediment storage must be provided for the
entrance and exit of the forebay,please refer to Figure 5 in Part C-3 of the Manual.
D E Q�� North Carolina Department of Environmental Quality I Division of Energy,Mineral and Land Resources
512 North Salisbury Street 1 1612 Mail Service Center I Raleigh,North Carolina 27699-1612
NORTH CAROLINA _
uepn ,t 0 B,im m W a.ar\ r 919.707.9200

c. The average depth calculation for the main pool appears to be off. If using Equation 3
to calculate the average depth, the volume of the shelf would be calculated as follows:
Depth—max— 1.0' (the depth of permanent pool over the deepest part of the vegetated
shelf), Perimeter= 549.5' (from Line 30 of the Wet Pond Page of the Supplement-EZ
Form), Width_submerged= 6.0' (based on pond geometry). This results in a shelf
volume of 1,648.5 cf(V_shelf=0.5 * Depth max * Perimeter * Width submerged).
This value is different than the value used in the calculations (6,390 cf, which
includes the permanent pool volume over both the vegetated shelf and main pool, not
just the volume over the vegetated shelf). Please revise the average depth calculation
as needed.
d. The drawdown calculation for the temporary ponding volume appears to be off.
Typically, when determining the average driving head on the orifice, a head of one
third of the starting head is used (the calculations appear to use half of the starting
head) and when selecting an orifice coefficient for this type of outlet structure, a
value of 0.6 is used. Non-typical values can be used in the drawdown equation
provided that you provide justification for doing so.
e. The design volume of a wet pond is the volume that can be stored above the
permanent pool surface elevation (192.0') and below the lowest bypass elevation
(193.7', the rim elevation of the outlet structure). Based on the provided stage-storage
table, the design volume of this wet pond would be approximately 21,700 cf(which
would not draw down within the required 2-5 day window). Please either revise the
orifice size so that the design volume draws down within the 2-5 day window or
revise the bypass invert so it corresponds to the design volume.
2. The following items were noted with the O&M Agreement Form:
a. Please revise the permanent pool elevations (187.0' for the forebay and 183.0' for the
main pool shown in the form, 192.0' per the plans).
b. Please revise the temporary pool surface elevations (the permanent pool surface
elevation of 192.0' is shown in the form).
3. The following items were noted with the Supplement-EZ Form:
a. Cover Page:
i. Lines 7-10—Please answer these items. It is noted that there are no surface waters
located on-site, however, we ask that the vegetated setback width be provided
(Line 7). The other items may be answered as "N/a".
b. Drainage Areas Page:
i. Entire Site Column—The entire site column is an accounting of the entire site
(similar to how the drainage area column is an accounting of the entire drainage
area to the SCM). Please include all BUA within the project area in this column,
whether or not it drains to the SCM. When an item asks for the "Drainage Area" of
the entire site, please use the project area. Please complete Lines 5, 6, & 18 for this
column. NOTE: Since this site has existing BUA, the density calculation method

outlined in 15A NCAC 02H .1003(1)(b) may be used to calculate the project
density.
ii. Lines 10 & 11 —It appears that the values from Line 10 were entered onto Line 11.
Please revise.
iii. Drainage Area 1 Column, Line 20—See earlier comment with regard to the design
volume.
c. Wet Pond Page:
i. Line 8—This item is required per General MDC 5 (the outlet structure and
emergency spillway would meet this requirement).
ii. Line 25 —See earlier comment with regard to the temporary pool/design volume.
iii. Line 26—Per the provided stage-storage table, the provided main pool surface area
at the permanent pool surface elevation is 7,810 sf(The surface area of the forebay
is not included in this item).
iv. Line 27—See earlier comment with regard to the sediment storage volume not
contributing to the volume of the main pool.
v. Line 28—See earlier comment about the average depth calculation.
vi. Line 31 —The width of the submerged portion of the vegetated shelf is measured
perpendicularly from the contour lines/permanent pool edge.
vii. Line 32—See earlier comment with regard to the sediment storage volume not
contributing to the volume of the main pool.
viii. Line 34—The cleanout depth of the forebay is the distance from the permanent
pool surface elevation to the top of the sediment storage zone in the forebay,
expressed in inches.
ix. Line 35 —See earlier comment with regard to the design volume.
x. Line 40—See earlier comment with regard to the drawdown calculations.
xi. Line 42—For berms and baffles to count for this item, they must extend above the
temporary poll surface elevation.
xii. Lines 43 &44—The depth to the forebay is measured form the permanent pool
surface elevation to the excavated bottom of the forebay near the entrance (Line
43) or near the exit (Line 44), expressed in inches. NOTE: Line 44 >Line 43 >=
[Line 34 + 6"].
4. Provide PDFs of all revisions, 2 hardcopies of revised plan sheets, 1 hardcopy of other
documents, and a response to comments letter briefly describing how the comments have
been addressed.
a. PDFs must be uploaded using the form at:
https:,I ledocs.deq.nc.g_ov/Forms/SW-Supplemental-Upload
b. Hard copies must be mailed or delivered to the following address:
i. For FedEx/UPS:
Jim Farkas
512 N. Salisbury Street, Office 640M
Raleigh, NC 27604
ii. For USPS:
Jim Farkas

1612 Mail Service Center
Raleigh, NC 27699-1612
iii. Hand Delivery:
Please reach out to me prior to hand delivering a submission to make sure that I
(or someone else in my group) will be able to receive the submission. Do not
leave the package in the foyer with the security guard.
NOTE: Hard copies should not be sent to a Regional Office. Doing so will delay
the review process and the submission package may be lost while being sent from
the Regional Office to me in the Central Office.
Please note that this request for additional information is in response to a preliminary review.
The requested information should be received by this Office prior to April 5, 2023, or the
application will be returned as incomplete. The return of a project will necessitate resubmittal
of all required items, including the application fee. Please reference the State assigned project
number SW6221201 on all correspondence.
If you need additional time to submit the information, please submit your request for a time
extension to the Division at the contact below. The request must indicate the date by which you
expect to submit the required information. The Division is allowed 90 days from the receipt of
a completed application to issue the permit.
The construction of any impervious surfaces, other than a construction entrance under an
approved Sedimentation Erosion Control Plan, is a violation of NCGS 143-215.1 and is subject
to enforcement action pursuant to NCGS 143-215.6A.
If you have any questions concerning this matter please feel free to contact me at
[e-mail] or(919) 707-3646.
Sincerely,
Jim Farkas
State Stormwater Engineer
DEMLR Post-Construction Stormwater Program
cc: Fayetteville Regional Office