SW3201201_Add Info_20210107

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Director
Marc Momsen, PE
223 N. Graham Street
Charlotte, NC 28202
NORTH CAROLINA
Environmental Quality
January 7, 2021
Subject: Request for Additional Information
Stormwater Permit No. SW3201201
Union County Sheriffs Office
Union County
Dear Mr. Momsen:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on December 4, 2020. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
Please provide a name for the point of contact for Union County building inspections
(Section III, 4 of the Application). This is required since this individual will be Cc'd a
copy of the permit once it is issued.
2. The checkbox next to "Ph II — Post construction" should not be checked since this project
is not claiming vested rights (Section IV, 2b).
3. Rays Fork appears to go through the southern portion of the property. Please include the
on -site surface water area in Section IV, 6 of the Application and recalculate Section IV,
7 & 8 and any other portion of the submission as needed.
4. There is a mismatch between the project area shown in the Application (33.44 acres,
Section IV, 7) and the Supplement-EZ Form (11.71 acres, Cover Page, Line 2). Please
revise for consistency. You may use either the property area or some other defined area
(such as the Limit of Disturbance, LOD) as the project area, just be consistent throughout
the submission.
5. Please show the area of Drainage Area 1 in square feet instead of acres (Section IV, 10).
6. The "off -site" portion of a drainage area is any portion of the drainage area to the SCM
that is located outside of the project area. Based on the provided information, it does not
DNorth Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
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_ 512 North Salisbury Street 11612 Mail Service Center I Raleigh, North Carolina 27699-1612
NORTH CAROLINA
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appear that there are any off -site portions of Drainage Area 1, please revie as needed
(Section IV, 10). If there are off -site portions of this drainage area, they should be
reported in the same column.
7. Please initial, in pen, the items that have been included in the Application submission
(Section VI). For items that are not required, please indicate "N/a" or something similar.
8. Please provide an additional copy of the Application as only one was provided in the
submission (Section VI, 1).
9. Please show the scale on plan sheet GO-02 (Section VI, 8f). Please ensure that all
applicable sheets have scales shown.
10. Please show the surface area of the on -site surface waters on the plans (Section VI, 8h).
11. Please dimension the project area with bearings and distances (Section VI, 8i).
12. Please dimension all of the BUA in the main set of plans (Section VI, 8j). The
information shown in the Application and Supplement-EZ Form should be verifiable on
the plans, similar to how it is shown in the impervious area exhibits in the calculations. It
is noted that the plans do have dimensions such as width, length, and radius for the BUA,
but we cannot accurately verify the areas on the paper copy of the plans (We could if we
had the CAD files, but we don't do that).
13. Please delineate the wetlands on the plans or provide a note stating that no wetlands exist.
Provide documentation of the qualifications and identity of the individual who made this
determination (Section VI, 8m).
14. Please delineate the drainage area to the proposed SCM in the main set of plans (Section
VI, 80).
15. Please show the required vegetated buffers from surface waters in the main set of plans
Section VI, 8p).
16. Please provide the property deed for this property (Section VI, 10).
17. Please provide some form of official documentation showing Gordon Vincent's position
within Union County (Section VI, 11).
18. As currently designed, the project does not meet the definition of Runoff Treatment (15A
NCAC 02H .1002(43)). In order to meet runoff treatment, the net increase in BUA must
be treated in one or more primary SCMs. Currently, there are only 189,356 sf of BUA
being treated in the sand filter whereas the net increase in BUA is larger than that. Please
revise as needed.
NOTE: Existing BUA may be treated in addition to part of the new BUA, so long as an
area equal to the net increase in BUA is treated in one or more primary SCMs.

19. The net increase in BUA from existing to proposed conditions for this project is unclear.
Per the plans, the project will have a total of 448,757 sf (10.3 ac) of BUA in proposed
conditions (plan sheet C3-00) whereas the calculations show that there will be a total of
11.185 acres of BUA in proposed conditions. Please revise as needed for consistency.
20. Please determine if you would like the base design or the alternative design permitted. I
can't permit two possible designs. If you are unsure of which design will ultimately be
constructed, you can seek approval for the more restrictive design (i.e. the one with more
BUA) and modify the permit if needed.
21. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:
i. Line 2 — Please earlier comment.
ii. Lines 27-32 — Please use the contact information for the licensed designer
that is signing & sealing this form. It's OK to have an EIT do the actual
design work so long as the licensed individual directs/supervises the work
and is willing to sign off on the work as "correct" (See the "certification
statement" on the cover page for more information).
b. Drainage Areas Page:
i. Entire Site Column:
1. Line 5 — See earlier comment. This value should be the total
amount of BUA that will exist on -site after construction has
finished. For this project, Line 5 = Line 13 + Line 7.
2. Lines 8 & 9 — See earlier comment. There should not be an off -site
component to the entire site since, by definition, everything within
the entire site is on -site.
ii. Drainage Area 1:
1. Line 17 — Based on this project's location, the design storm is 1.0
inches. You may elect to design the SCM for larger storms (Since
some local jurisdictions require quantity management), but since
this is a State reviewed project, you will only need to design for the
1.0 inch storm.
2. Line 18 — The design volume should be based on the design storm
(See prior comment). Since this SCM is a sand filter you may
reduce the design volume by 25% (In accordance with Sand Filter
MDC 3).
3. Line 19 — Please use either the Simple Method or the Discrete
NRCS Method to calculate the design volume. More information
can be found in Part B of the Stormwater Design Manual.
c. Sand Filter Page:
i. Line 2 — See earlier comment.
ii. Line 18 — Per the provided SHWT information, the closest boring to the
proposed sand filter is B-15. The ground surface elevation at boring B-15

is 538 and the boring was done to a depth of 9.4'. This means that the
SHWT is at or below 528.6. Please use this value, "< 528.6", for the
SHWT elevation.
iii. Lines 23 & 30 — These volumes should only take into consideration the
provided storage below the invert of the lowest filter bypass (Y orifice)
elevation.
iv. Lines 26 & 32 — Please separate the stage -storage table for the sand filter
into sediment chamber and sand chamber so that this information and
Lines 23 & 30 can be verified.
v. Lines 28 & 34 — The ponding depth is the distance from the bottom of the
chamber to the invert of the lowest filter bypass elevation.
vi. Line 35 — The elevation of the bypass device is the invert of the lowest
filter bypass.
vii. Line 38 — Please specify ASTM C33 or equivalent (per Sand filter MDC
6).
viii. Line 39 — Plan sheet C3-04 shows the depth of sand above the underdrain
pipe as a minimum of 1.5'.
22. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, and 1 hardcopy of other
documents.
a. Pdfs must be uploaded using the form at:
hgps://edocs.deq.nc.gov/Forms/SW Project Submittal
b. Hard copies must be mailed or delivered to the following address:
Jim Farkas
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
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 February 6, 2021, 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 SW3201201 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 [phone].

Sincerely,
)6W4�
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Mooresville Regional Office