SW1200501_Add Info_20200731

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
BRIAN WRENN
Acting Director
Scott Baldwin, PE
55 Broad Street
Asheville, NC 28801
NORTH CAROLINA
Environmental Quality
July 31, 2020
Subject: Request for Additional Information
Stormwater Permit No. SW1200501
Car Rider Improvements Fairview Elementary School
Buncombe County
Dear Mr. Baldwin:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on May 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:
Section II, 2 — Since all three parcels are owned by the Buncombe County Board of
Education, you do not need to consider the proposed SCMs as off -site facilities. The only
reason it would be beneficial to consider these proposed facilities as off -site facilities is if
the Board of Education plans on selling off either of the lots that the proposed SCMs are
located on in the near future. Please let me know if you would like to keep either
proposed SCM as an off -site facility as there is some legal paperwork that needs to be
completed to ensure the long-term functionality of the off -site facility.
2. Since there are two proposed SCMs for this project, the drainage area to each should be
reported in Section IV, 10 of the Application. Since the Limit of Disturbance (LOD) is
being used as the project area, any portion of the drainage area to these proposed SCMs
that is outside the LOD should be considered as off -site drainage.
3. No off -site areas are shown in Section IV, 10 of the Application. Either Section IV, 11 is
not needed or the off -site drainage areas should be shown in Section IV, 10 of the
Application.
4. Please provide a hard copy of the Supplement-EZ Form with an original signature
(Section V & Section VI, 3).
DNorth Carolina Department of Environmental Quality I Division of Energy, Mineral and Land Resources
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5. Please ensure that the entire O&M Agreement Form is included in the submission
(Section V & Section VI, 3). The O&M agreement form uses Macros to generate the
needed pages based on the information entered on the cover page. Please ensure that all
of the pages have loaded (Enable editing, enable Macros, click on the "Click to update
Manual" link about midway down the cover page). The form will need to be re -signed.
6. Please provide an additional copy of the Application Form (Section VI, 1). Only an
original hard copy was provided. The additional copy does not require an original
signature.
7. Please provide a USGS topographic map that clearly shows the project area (Section VI,
6).
8. The provided SCM design calculations are lacking (Section VI, 7). Please provide
calculations for the following:
a. The Design Volume — Using either the Simple Method (For the entire drainage
area to each proposed SCM) or the NRCS Discrete Curve Number Method (For
the pervious and impervious parts of the entire drainage area to each proposed
SCM) and the design storm of 1.0 inches (See later comment).
b. The actual depth of the Design Volume in each SCM — This value should be
calculated/interpolated from a stage -storage table (See later comment).
c. Peak Attenuation Volume — Provide calculations showing how the peak
attenuation volume is calculated.
d. The actual depth of the Peak Attenuation Volume in each SCM — This value
should be calculated/interpolated from a stage -storage table (See later comment).
e. Media Drawdown Rate — Calculations showing that a drawdown rate of at least 1
inch per hour can be maintained through the media and underdrains (Bioretention
MDC 9).
9. Please clearly show and dimension the project boundary being used for this project,
including bearings and distances (Section VI, 8i).
10. Please clearly identify and dimension the BUA for this project for both existing and
proposed conditions (Section VI, 8j). The information shown in the calculations,
Application, and Supplement-EZ Form should be verifiable on the plans.
11. 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).
12. Please show the drainage areas for the proposed SCMs on the main set of plans (Section
VI, 80).

13. Please provide a soils report showing the Seasonal High Water Table (SHWT) elevation
information for the two proposed SCMs (Section VI, 9). The Web Soil Survey should be
used in conjunction with, not as a replacement to actual on -site borings.
14. Since the Property Owner is the Applicant, Section IX should not be included. If Tony
Baldwin is a more appropriate person to be signing on behalf of the Board of Education,
he should be listed in Section III, 1 & should sign Section X (This would require a new,
original signature on the Application). If Clark Wyatt will remain the Applicant
signatory, I can, with your permission, cross out the provided signature in the original,
signed, hard -copy of the form in Section IX (The form would not need to be resigned, but
the electronic version of the form would need to have this section crossed out as well).
Please let me know how you would like to address this.
15. Please refer to the latest version of the Stormwater Design Manual for the latest design
requirements (The calculations appear to reference an old version of the Manual). The
Manual can be found at the following link: https://deq.nc.gov/about/divisions/energy-
mineral-land-resources/energ_y-mineral-land-permit- guidance/stormwater-bmp-manual
16. The design volumes do not appear to be calculated correctly (General MDC 1). Please
use either the Simple Method (For the entire drainage area to each proposed SCM) or the
NRCS Discrete Curve Number Method (For the pervious and impervious parts of the
entire drainage area to each proposed SCM). More information can be found in the
Design Manual, Part B.
17. Per plan sheet C-505, the side slopes of the proposed SCMs appear to be steeper than 3:1
(General MDC 3). Please revise.
18. Please ensure that there is at least a 2 foot separation between the lowest excavated point
of each proposed bioretention cell and the SHWT associated with these locations
(Bioretention MDC 1).
19. If the proposed SCMs are being used for peak attenuation, please show the peak
attenuation elevation on the plans (Bioretention MDC 3).
20. Please provide a stage -storage table for the proposed SCMs so that the temporary
ponding depth (Bioretention MDC 2), peak attenuation elevation (Bioretention MDC 3),
and design volume (General MDC 1) values can be verified.
21. Please provide a detailed plan view of the proposed SCMs (15A NCAC
02H .1042(2)(h)). This will, among other things, allow for verification of the locations
and quantities of the underdrains.
22. Please correct the following issues with the Supplement-EZ Form:
a. Cover Page:

i. Lines 7-10 — Since there are no surface waters located on -site, these items
should be "N/a"
b. Drainage Areas Page:
i. Please complete the Entire Site column. This is an accounting of the area
within the project area. Lines 4, 8, 9, & 17-19 do not need to be
completed.
ii. Lines 5, 7, 10, 13, 16, & 18 — Revise as needed in accordance with earlier
comment. This should be an accounting of the entire drainage area to each
proposed SCM, not just the impervious areas within the project area.
iii. Line 17 — The design storm depth for this project is 1.0 inches (Per 15A
NCAC 02H .1017(5)).
c. Bioretention Cell Page:
i. Line 9 — Please specify in the Additional Information box (Line 44).
ii. Line 18 — Please include this item.
iii. Line 19 — The bottom of the bioretention cell is the excavated bottom of
the SCM, not the top of the media layer.
iv. Line 20 — This should be based on the actual temporary ponding depth
associated with the design volume (Based on the design storm of 1.0
inches).
v. Line 27 — Plan sheet C-505 indicates that the underdrain diameter of
bioretention cell 1 is 6 inches whereas 8 inches is shown in the
Supplement-EZ Form. Please revise for consistency.
vi. Line 37 — This value should be "<50" since a specific value was not
specified.
vii. Lines 39, 42, & 43 are required, please complete these items.
23. Provide pdfs of all revisions, 2 hardcopies of revised plan sheets, and 1 hardcopy of other
documents. Pdfs must be uploaded using the form at:
https://edocs.deq.nc.gov/Forms/SW Project Submittal
While it is not required, it is recommended that pretreatment be provided for each proposed
bioretention cell.
It is further recommended that Buncombe County be contacted to ensure that they are unable
to review this project since Buncombe County is delegated to implement their own post -
construction stormwater program.
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 August 30, 2020, 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 SW1200501 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,
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Asheville Regional Office