SW6080804_401 Certification Application_20081009

NCDENR
Permit Number: _SW601r0$04-t
(to be provided by DWQ)
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STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
Project name
Contact name
Phone number
Date
Drainage area number
BUb JPALUINU
704-227-9424. -
.SeOtember 11. 2008
I I.-j DESIGN?INF....,ORMAT10Nna , ,•*i rt tt'arfi k m ; 'Wzn kws n , g'
Site Characteristics
Drainage area 13,86300 ftZ
Impervious area .9,862.00 ftZ
Percent impervious 71.1% %
Design rainfall depth 1.00 inch
Peak Flow Calculations
1-yr, 24-hr runoff depth 3.04 in
1-yr, 24-hr intensity 0.13 in/hr
Pre -development 1-yr, 24-hr peak flow 0.80 ft3/sec
Post -development 1-yr, 24-hr peak flow 1.25 ft3/sec
Pre/Post 1-yr, 24-hr peak control 0.45 ft3/sec
Storage Volume: Non -SR Waters
Design volume 940.89 ft3 %
Storage Volume: SR Waters
Pre -development 1-yr, 24-hr runoff
ft3
Post -development 1-yr, 24-hr runoff
ft3
Minimum volume required
0.00 ft3
Volume provided
ft3
Cell Dimensions
Ponding depth of water
10.20 inches
OK
Ponding depth of water
0.85 ft
Surface area of the top of the bioretention cell
1332.00 ftZ
OK
Length:
90.00 ft
OK
Width:
10.00 ft
OK
-or- Radius
It
Soils Report Summary
Drawdown time, ponded volume
i 5.10 hr
OK
Drawdown time, to 24 inches below surface
1200 hr
OK
Drawdown time, total:
17.10 hr
In -situ soil:
Soil permeability
1.98 in/hr
OK
Planting media soil:
Soil permeability
1.00 in/hr
OK
Soil composition
% Sand (by weight)
85%
OK
% Fines (by weight)
12%
OK
% Organic (by weight)
3%
OK
Total: 100%
Form SW401-Bioretention-Rev.3
CIN t- 1 c. 4— or. T!L-1'ri2. s T(z
+l`s�
Parts I and II. Design Summary, Page 1 of 2

Permit Number. S" r"FOTOI
(to be provided by D WQ)
Ph6sphoruslhdF(P=Index) --- unitless -----
Basin Elevations
Temporary pool elevation
Planting elevation (top of the mulch)
Bottom of the cell
Planting depth
Depth of mulch
SHWT elevation
Are underdrains being installed?
How many clean out pipes are being installed?
What factor of safety is used for sizing the underdrains? (See
BMP Manual Section 12.3.6)
Additional distance between the bottom of the planting media and
the bottom of the cell to account for underdrains
Bottom of the cell required
Distance from bottom to SHWT
Type of bioretention cell (answer "Y" to only one of the two
following questions):
Is this a grassed cell?
Is this a cell with trees/shrubs?
Planting Plan
500.60 fmsl
499.75 fmsl
497.75 fmsl
2.00 It
0.00 inches
469.50 fmsl
Y (Y or N)
2
10.00
1 ft
496.75 fmsl
27.25 ft
Insufficient mulch depth. ?Cr Mr" R",)-JdnC--
OK Mulch. A .i- .+CLr Ico
b�+ui ceUS _
10
OK
OK
Y (Y or N) OK
(Y or N)
Number of tree species 0 More species are recommended.
Number of shrub species 0 More species are recommended. OK G v�A i S
Number of herbaceous groundcover species 0 More species are recommended. C I': L L
Additional Information
Does volume in excess of the design volume bypass the Y (Y or N) OK
bioretention cell?
Does volume in excess of the design volume flow evenly distributed
through a vegetated filter? N (Y or N) Excess volume must pass through filter. AaA;'1 �a�.
What is the length of the vegetated filter? 45-ft—
eJ cF.
Does the design use a level spreader to evenly distribute flow? N (Y or N) Show how Flow is evenly distributed.
Is the BMP located at least 30 feet from surface waters (50 feet if
SA waters)?
Is the BMP located at least 100 feet from water supply wells?
Are the, vegetated side slopes equal to or less than 3:1?
Is the BMP located in a recorded drainage easement with a
recorded access easement to a public Right of Way (ROW)?
Inlet velocity (from treatment system)
Is the area surrounding the cell likely to undergo development in
the future?
Are the slopes draining to the bioretention cell greater than 20%?
Is the drainage area permanently stabilized?
Pretreatment Used
(Indicate Type Used with an "X" in the shaded cell)
Gravel and grass
(8 inches gravel followed by 3-5 ft of grass)
Grassed swale
Forebay
Y
(YorN)
OK
Y
(Y or N)
OK
Y
(Y or N)
OK
N
(Y or N)
Insufficient ROW location. f-ASEff.,,* ZS PrdP�XcQ
1.00 ft/sec
OK
N
(Y or N)
OK
N
(Y or N)
OK
Y
(Y or N)
OK
Form SW401-Bioretenlion-Rev.3 Parts I and II. Design Summary, Page 2 of 2