SW5120201_401 Certification Application_20120315

Permit Number:.sW.S7Zo�l
(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 tilled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
I. , PROJECT. INFORMATION'_...::.,..,
e
Project name
Dollar General - Spring Hope
Contact name
Matt Lowder - Triangle Site Design, PLLC
Phone number
919-553-6570
Date
January 26,2012
Drainage area number
Bio-Retention Pond
II. DESIGN.INFORMATION
5a
Site Characteristics
Drainage area
45,740 ftz
Impervious area
32,230 ft'
Percent impervious
70,5% %
Design rainfall depth
1.0 inch
Peak Flow Calculations
Is preipost control of the 1-yr, 24-hr peak flow required?
1-yr, 24-hr runoff depth
1-yr, 24-hr intensity
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak control
Storage Volume: Non -SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre -development 1-yr, 24-hr runoff
Post -development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Cell Dimensions
Ponding depth of water
Podding depth of water
Surface area of the top of the bioretention cell
Length:
Width:
-or- Radius
Media and Soils Summary
Drawdown time, ponded volume
Drawdown time, to 24 inches below surface
Drawdown time, total:
In -situ soil:
Soil permeability
Planting media soil:
Soil permeability
Soil composition
% Sand (by volume)
% Fines (by volume)
% Organic (by volume)
Y (Y or N)
2.74 in
3.97 inihr
0.608 ft3/sec
2,934 ft'/sec
2.326 ft'/sec
2,608.0 ft3
2,650.0 ft3 OK
ft3
ft3
f13
0 ft3
ff3
12 inches
1.00 fl
2,650.0 ff2
130 ft
20 ft
ft
OK
OK
OK
OK
6 hr OK
20 hr OK
26 hr
0.25 in/hr
2.00 in/hr
87%
8%
i
rr��S!,EAL B
t 24434 n
0
/ gi�til i�ir �5 y • �
//� �.It7�T�CLJ . S •�`
Insufficient. Increase infiltration rate or include underdrains.
OK
OK
OK
OK
Total: 100%
Phosphorus Index (P-Index) of media 10 (unitless) OK
Form SW401-Bioretention-Rev.8
June 25. 2010
Parts I and II. Design Summary, Page 1 of 2

Permit Number:
(to be provided by DwQ)
Basin Elevations
Temporary pool elevation
251.00 fmsl
Type of bioretention cell (answer "Y" to only one of the two
following questions):
Is this a grassed cell?
Y (Y or N) OK
Is this a cell with trees/shrubs?
N (Y or N)
Planting elevation (top of the mulch or grass sod layer)
250 fmsl
Depth of mulch
0 inches Insufficient mulch depth, unless installing grassed cell.
Bottom of the planting media soil
248 fmsl
Planting media depth
2 It
Depth of washed sand below planting media soil
0 ft
Are underdrains being installed?
Y (Y or N)
How many clean out pipes are being installed?
5
What factor of safety is used for sizing the underdrains? (See
2
BMP Manual Section 12.3.6)
Additional distance between the bottom of the planting media and
1 ft
the bottom of the cell to account for underdrains
Bottom of the cell required
247 fmsl
SHWT elevation
245 fmsl
Distance from bottom to SHWT
2 ft
Internal Water Storage Zone (IWS)
Does the design include IWS
N
(Y or N)
Elevation of the top of the upturned elbow
fmsl
Separation of IWS and Surface
250 ft
Planting Plan
Number of tree species
0
Number of shrub species
Number of herbaceous groundcover species
Additional Information
Does volume in excess of the design volume bypass the
Y
(Y or N)
bioretention cell?
Does volume in excess of the design volume flow evenly distributed
7(Y or N)
through a vegetated filter?
What is the length of the vegetated filter?
ft
Does the design use a level spreader to evenly distribute flow?
N
(Y or N)
Is the BMP located at least 30 feet from surface waters (50 feet if
Y
(Y or N)
SA waters)?
is the BMP located at least 100 feet from water supply wells?
Y
(Y or N)
Are the vegetated side slopes equal to or less than 3:1?
Y
(Y or N)
Is the BMP located in a proposed drainage easement with access
Y
(Y or N)
to a public Right of Way (ROW)?
Inlet velocity (from treatment system)
2 ftlsoc
Is the area surrounding the cell likely to undergo development in
N
(Y or N)
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
OK
OK
a
OK
0KNa, �3�� oK ^2��
Show how flow is evenly distributed.
OK
OK
OK
OK
Insufficient inlet velocity unless energy dissipating devices are
being used.
OK
N (Y or N) OK
Y (Y or N) OK
X
OK
x
Form SW401-Bioretention-Rev.8
June 25, 2010 Parts I and II. Design Summary, Page 2 of 2

Permit No,
(to be assigned by DWQ)
IIL' REQUIRED ITEI& CHECKLIST
Please indicate the page or plan sheet numbers where the supporting docurmentatron 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.
Pagel Plan
Initials Sheet No.
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.
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2. Plan details (1" = 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
iYffC C-1 a
3. Section view of the bioretention cell (1" = 20' or larger) showing:
Side slopes, 3:1 or lower
Underdrain system (if applicable), and
Bioretention cell layers {ground level and slope, pre-treatment, pending 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]
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 DWO, 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
P-index.
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5. Adetailed planting plan (1" = 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.
✓ U C� C-10
6. A construction sequence that shows how the bioretention cell will be protected from sediment until the
entire drainage area is stabilized.
My- WC
7. The supporting calculations (including underdrain calculations, if applicable).
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8. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
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9. A copy of the deed restriction.
Form SW401-Bioretention-Rev.7 Part III, Page 1 of 1