SW1190801_Add Info_20200116

ROY COOPER
Governor
MICHAEL S. REGAN
Secretary
S. DANIEL SMITH
Director
Jacob D. Grieb, PE
403 E. Market Street
Johnson City, TN 37601
NORTH CAROLINA
Environmental Quality
January 16, 2020
Subject: Request for Additional Information
Stormwater Permit No. SW1190801
Leicester Volunteer Fire Department
Buncombe County
Dear Mr. Grieb:
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater
Management Permit Application for the subject project on December 15, 2019. A review of that
information has determined that the application is not complete. The following information is
needed to continue the stormwater review:
November 22, 2019 Comment 12 —
a. For bioretention cell 1, the bottom surface elevation is 2,167 ft, the depth of the
bioretention cell is 3.5 ft and the minimum required separation from the SHWT is
2 ft which means that the SHWT must be at or below 2,161.5 ft at this location.
The closest boring to this bioretention cell is boring B-03 which terminates at
2,169 ft (7.5 feet short of the maximum allowable SHWT elevation). The second
closest boring is B-04 which terminates at 2,168 ft (6.5 feet short of the maximum
allowable SHWT elevation).
b. For bioretention cell 2, the bottom surface elevation is 2,155 ft, the depth of the
bioretention cell is 3.5 ft and the minimum required separation from the SHWT is
2 ft which means that the SHWT must be at or below 2,149.5 ft at this location.
The closest boring to this bioretention cell is boring B-12 which terminates at
2,162.5 ft (13 feet short of the maximum allowable SHWT elevation). The second
closest boring is B-11 which terminates at 2,174 ft (24.5 feet short of the
maximum allowable SHWT elevation).
c. Please provide location specific soil borings that show that the SHWT is at least 2
ft lower than the lowest excavated point of each bioretention cell (Bioretention
MDC 1).
2. November 22, 2019 Comment 19 — Per the Manual, Part C-0, the maintenance easement
is,
D EQ 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 _
o.PaWnamofEnvironmental Quality /� 919.707.9200

"The entire footprint of the SCM system..., plus an additional ten or more feet
around the SCM to provide enough room to complete maintenance tasks. This
SCM system includes the side slopes, forebay, riser structure, SCM device, and
basin outlet, dam embankment, outlet, and emergency spillway. "
Please ensure that the requisite areas are included in the maintenance access and is shown
on the plans (General MDC 8).
3. Please correct the following issues with the Supplement-EZ Form:
a. Drainage Areas Sheet:
i. Please fill out the "Entire Site" column with information for the entire site
(Everything within the property boundaries).
ii. Please include information for Line 5. This is the total amount of BUA in
proposed conditions within the entire site/drainage area.
iii. Please include information for Line 7. This is the new (net increase)
amount of BUA that will be added to the entire site/drainage area. Line 7
should be the sum of the items on Line 10 and should not take into
account any existing BUA on the site in existing conditions (For this
project, existing BUA should be reported on line 13).
iv. Please include information for Line 16. The percent BUA is the total
amount of BUA in proposed conditions (Line 5) divided by the total area
of the entire site/drainage area, expressed as a percent.
v. Please include information for Line 20. Drainage Area 1 contains a BUA
of type "Other" please elaborate on line 20 what this other type of BUA is.
vi. For Drainage Area 2, the off -site information (Lines 8 & 9) does not
match the table in Section IV, 10 of the Application. Line 8 of the
Supplement-EZ Form should include the total (pervious and impervious)
off -site portion of the drainage area whereas line 9 should only include the
BUA located within the off -site portion of the drainage area.
b. Bioretention Cell Sheet:
i. Line 9 — Sheet C401 does not appear to show a drawdown orifice for
dewatering. Please revise for consistency.
ii. Line 18 — This item is applicable as it is required for Bioretention MDC 1.
If a boring is conducted to a depth of 2 ft below the lowest point of the
proposed facility and the SHWT is not encountered, the SHWT depth may
be expressed as "< ####" where #### is the lowest elevation of the boring.
iii. Line 19 — This elevation should be the elevation of the excavated bottom
of the facility This depth should be 42 in lower than the planting surface
elevation (30 in of media mix, 4 in of washed sand, and 8 in of #57 stone).
iv. Line 26 — Since IWS is proposed for the bioretention cells, the in situ soil
infiltration rate is not needed.
4. 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:
hgps://edocs.deq.nc.gov/Forms/SW Project Submittal

While it is not required, it is recommended that:
- Off -site drainage from the upstream property be diverted around bioretention #2 since the
applicant cannot maintain control over the development of property that they do not own.
If, in the future, additional BUA is built outside of the property boundary, but within the
drainage area to bioretention #2, the facility may become undersized and non -compliant
with the regulations.
- Some form of pretreatment and flow dispersion be provided for the inflow to the
bioretention facilities. A forebay can provide both of these functions.
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 15, 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 SW1190801 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,
V` vl
Jim Farkas
Environmental Engineer
Stormwater Program
cc: Asheville Regional Office