Q Mart - Supplement_Bioretention_Rev.9_Locked

Permit Number:__________________
(to be provided by DWQ)
I. PROJECT INFORMATION
Project name
Contact name
Phone number 910-574-0278
Date
Drainage area number
Site Characteristics
Drainage area 130,782 ft2
Impervious area 34,640 ft2
Percent impervious 26.5%%
Design rainfall depth 1.0 inch
Peak Flow Calculations
Is pre/post control of the 1-yr, 24-hr peak flow required? Yes (Y or N)
1-yr, 24-hr runoff depth 3.04 in
1-yr, 24-hr intensity 5.22 in/hr
Pre-development 1-yr, 24-hr peak flow 0.000 ft3/sec
Post-development 1-yr, 24-hr peak flow 0.000 ft3/sec
Pre/Post 1-yr, 24-hr peak control 0.000 ft3/sec
Storage Volume: Non-SA Waters
Minimum volume required 2,542.0 ft3
Volume provided 10,969.0 ft3 OK
Storage Volume: SA Waters
1.5" runoff volume ft3
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required 0 ft3
Volume provided ft3
Cell Dimensions
Ponding depth of water 9 inches OK
Ponding depth of water 0.75 ft
Surface area of the top of the bioretention cell 4,833.0 ft2 OK
Length:112 ft OK
Width:45 ft OK
-or- Radius ft
Media and Soils Summary
Drawdown time, ponded volume 9 hr OK
Drawdown time, to 24 inches below surface 24 hr OK
Drawdown time, total:33 hr
In-situ soil:
Soil permeability 0.27 in/hr Insufficient. Increase infiltration rate or include underdrains.
Planting media soil:
Soil permeability 1.00 in/hr OK
Soil composition
% Sand (by volume)85%OK
% Fines (by volume)10%OK
% Organic (by volume)5%OK
Total:100%
Phosphorus Index (P-Index) of media 10 (unitless)OK
II. DESIGN INFORMATION
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.
May 12, 2018
Q Mart Convenience Store
Biju George
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
BIORETENTION CELL SUPPLEMENT
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 86.45 fmsl
Type of bioretention cell (answer "Y" to only one of the two
following questions):
Is this a grassed cell?Yes (Y or N)
Is this a cell with trees/shrubs?No (Y or N)
Planting elevation (top of the mulch or grass sod layer)230.5 fmsl
Depth of mulch 0 inches Insufficient mulch depth, unless installing grassed cell.
Bottom of the planting media soil 228 fmsl
Planting media depth 2.5 ft
Depth of washed sand below planting media soil 0.33 ft
Are underdrains being installed?Yes (Y or N)
How many clean out pipes are being installed?5 OK
What factor of safety is used for sizing the underdrains? (See
BMP Manual Section 12.3.6)10 OK
Additional distance between the bottom of the planting media and
the bottom of the cell to account for underdrains 0 ft
Bottom of the cell required 227.67 fmsl
SHWT elevation 224.7 fmsl
Distance from bottom to SHWT 2.97 ft OK
Internal Water Storage Zone (IWS)
Does the design include IWS Yes (Y or N)
Elevation of the top of the upturned elbow 229 fmsl
Separation of IWS and Surface 1.5 ft OK
Planting Plan
Number of tree species
Number of shrub species
Number of herbaceous groundcover species
Additional Information
Does volume in excess of the design volume bypass the
bioretention cell?No (Y or N)Enter Data
Does volume in excess of the design volume flow evenly
distributed through a vegetated filter?No (Y or N)Enter Data
What is the length of the vegetated filter?ft
Does the design use a level spreader to evenly distribute flow?No (Y or N)Enter Data
Is the BMP located at least 30 feet from surface waters (50 feet if
SA waters)?Yes (Y or N)Enter Data
Is the BMP localed at least 100 feet from water supply wells?Yes (Y or N)Enter Data
Are the vegetated side slopes equal to or less than 3:1?Yes (Y or N)Insufficient vegetated side slopes.
Is the BMP located in a proposed drainage easement with access
to a public Right of Way (ROW)?No (Y or N)Insufficient ROW location.
Inlet velocity (from treatment system)ft/sec
Is the area surrounding the cell likely to undergo development in
the future?No (Y or N)Enter Data
Are the slopes draining to the bioretention cell greater than 20%?No (Y or N)Insufficient slopes for design.
Is the drainage area permanently stabilized?Yes (Y or N)Insufficient stabilization.
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)x
Grassed swale
Forebay
Other
OK
Form SW401-Bioretention-Rev.8
June 25, 2010 Parts I and II. Design Summary, Page 2 of 2