SW3120102_401 Ceritification Application_20120208

Permit Number,
(to be provided by DWO)
ATOM
y r
HCDEHR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
This form must be titled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
!:'PROJECTINFORMATION°
Project name AutoZone - Indian Trail, NC
Contact name Matt Lowder - Triangle Site Desgn, PLLC
Phone number 919-553-6570
Date January 23, 2012
Drainage area number Bio-Retention Pond
II. DESIGN INFORMATION ,,_'
Site Characteristics
Drainage area
37,900 ft2
Impervious area
30,042 ft2
Percent impervious
79.3% %
Design rainfall depth
1.0 inch
Peak Flow Calculations
Is prelpost control of the 1-yr, 24-hr peak flow required?
Y (Y or N)
1-yr, 24-hr runoff depth
2-92 in
1-yr, 24-hr intensity
3.97 in/hr
Pre -development 1-yr, 24-hr peak flow
1.040 ft'/sec
Post -development 1-yr, 24-hr peak flow
3.550 f<31sec
Pre/Post 1-yr, 24-hr peak control
2,510 ft3lsec
Storage Volume; Non -SA Waters
Minimum volume required
2,412.0 ft'
Volume provided
2,475.0 ft'
Storage Volume: SA Waters
1.5' runoff volume
tt3
Pre -development 1-yr, 24-hr runoff
ff3
Post -development 1-yr, 24-hr runoff
ft3
Minimum volume required
0 ft3
Volume provided
It
Cell Dimensions
Ponding depth of water
12 inches
Ponding depth of water
1.00 ft
Surface area of the top of the bioretention cell
2,475.0 ft2
Length:
130 ft
Width:
10 ft
-or- Radius
ft
Media and Soils Summary
Drawdown time, ponded volume
6 hr
Drawdown time, to 24 inches below surface
20 hr
Drawdown time, total:
26 hr
In -situ soil:
Solt permeability
0.16 in/hr
Planting media soit:
Soil permeability
2.00 in/hr
Soil composition
% Sand (by volume)
87%
% Fines (by volume)
8%
% Organic (by volume)
5%
Total:
100%
OK
OK
OK
OK
OK
OK
OK
o+>•uoc a �jb'
fi
t" SEAL
r!!-riiti tit' %y
Insufficient. Increase infiltration rate or include underdrains.
OK
OK
OK
OK
Phosphorus Index (P-Index) of media 10 (unitless) OK
Form SW401-Bioretention-Rev.8
June 25, 2010
Parts I and $1 Design Summary, Page 1 of 2

1
Basin Elevations
Temporary pool elevation
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 elevation (top of the mulch or grass sod layer)
Depth of mulch
Bottom of the planting media soil
Planting media depth
Depth of washed sand below planting media soil
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
SHWT elevation
Distance from bottom to SHWT
Internal Water Storage Zone (IWS)
Does the design include IWS
Elevation of the top of the upturned elbow
Separation of IWS and Surface
Planting Plan
Number of tree species
Number of shrub species
Number of herbaceous groundcover species
Additional Information
Does volume in excess of the design voiume bypass the
bioretention cell?
Does volume in excess of the design volume flow evenly distributed
through a vegetated filter?
What is the length of the vegetated filter?
Does the design use a level spreader to evenly distribute flow?
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 proposed drainage easement with access
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
(flinches gravel followed by 3-5 ft of grass)
Grassed Swale
Forebay
Other
Permit Number:
(to be provided by DWQJ
630.00 fmsl
Y (Y or N) OK
N (Y or N)
629 fmsl
0 inches Insufficient mulch depth, unless installing grassed cell.
627 fmsl
2 ft
0 ft
Y (Y or N)
6 OK
2 OK
1ft
626 fmsl
597 fmsl
29 ft OK
Y (Y or N)
627 fmsl
2 ft OK
0
Y (Y or N) OK
y (Y or N) OK
ft
N (Y or N) Show how flow is evenly distributed.
Y (Y or N)
OK
Y (Y or N)
OK
Y (Y or N)
OK
Y (Y or N)
OK
2 ftlsec
Insufficient inlet velocity unless energy dissipating devices are
being used.
N (Y or N)
OK
N (Y or N) OK
Y (Y or N) OK
X
OK
x
Form SW401-Bioretention-Rev.6
June 25, 2010
in
Parts I and ll. Design Summary, Page 2 of 2

Permit No:
(to be assigned by Dvt/O)
III. REQUIRED ITEMS CHECKLIST
Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package
will result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided
to indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a
requirement has not been met, attach justification.
Page/ Plan
Initials Sheet No,
/i't£L-• 0-1) el. 5
1. Plans (1" - 50' or larger) of the entire site showing:
Design at ultimate build -out,
Off -site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Cell dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Recorded drainage easement and public right of way (ROW),
Clean out pipe locations,
Overflow device, and
Boundaries of drainage easement.
2. Plan details (V = 30' or larger) for the bioretention cell showing:
Cell dimensions
Pretreatment system,
High flow bypass system,
Maintenance access,
Recorded drainage easement and public right of way (ROW),
Design at ultimate build -out,
Off -site drainage (if applicable),
Clean out pipe locations,
Overflow device, and
Boundaries of drainage easement.
Indicate the P-Index between 10 and 30
l4 e S
3. Section view of the bioretention cell W = 20' or larger) showing:
Side slopes, 3:1 or lower
Underdrain system (if applicable), and
Bioretention cell layers [ground level and slope, pre-treatment, ponding depth, mulch depth, fill media
depth, washed sand, filter fabric (or choking stone if applicable), #57 stone, underdrains (if applicable),
SHWT level(s), and overflow structure]
1 L i!V05
4. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. The
results of the soils report must be verified in the field by DWQ, by completing & submitting the soils
investigation request form. County soil maps are not an acceptable source of soils information. All
elevations shall be in feet mean sea level (fmsl). Results of soils tests of both the planting soil and the in
situ soil must include:
Soil permeability,
Soil composition (% sand, % fines, % organic), and
/Nit- el. 5
P-index.
5. A detailed planting plan (V = 20' or larger) prepared by a qualified individual showing:
A variety of suitable species,
Sizes, spacing and locations of plantings,
Total quantity of each type of plant specified,
A planting detail,
The source nursery for the plants, and
Fertilizer and watering requirements to establish vegetation.
IW4 el-3, ciS
6. A construction sequence that shows how the bioretention cell will be protected from sediment until the
entire drainage area is stabilized.
mit- L4^ S
7, The supporting calculations (including underdrain calculations, if applicable),
IhfLr -S! 94 TTj
8. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
14f i L N
9. A copy of the deed restriction.
Form SW401-13ioretention-Revl Part III, Page 1 of 1