SW5120203_Supplement_20120207

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STORMWATER MANAGEMENT PERMIT APPLICATI
401 CERTIFICATION APPLICATION EORN
E C E� U E
2of w a rF,�p
MAY 2 4 2012
.MRM NC OENR
Raleigh Regional Office
WETLAND SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part Ill) must be printed, filled out and submitted along with all the required information.
I. PROJECT INFORMATION
Project name State Employees' Credit Union - Siler City
Contact name Jon Aldridge
Phone number 919-361-5000
Date February 7, 2011
Drainage area number 1A - To SWMF
II. DESIGN INFORMATION
Site Characteristics
Drainage area 97,359,00 ftZ
Impervious area 67,935.00 ftZ
Percent impervious 69.8% %
Design rainfall depth 1.00 inch C R
Peak Flow Calculations �0 4� Vrk1-yr, 24-hr rainfall depth 2.99 in�y
1-yr, 24-hr intensity 0.12 inlhr Q SFAi. �r
Pre -development 1-yr, 24-hr runoff 0.37 ft3lsec 9—
Post -development 1-yr, 24-hr runoff 0.32 ft Isec y
_
44
Pre/Post 1 •yr, 24-hr peak control 0.05 ft3lsec 4,N �4
Storage Volume: Non -SA Waters �N A.
Minimum required volume 5,503.00 ft3
Volume provided (temporary pool volume) 5,563.00 ft3 OK of fe$ ZP17-
Storage Volume: SA Waters Parameters
1.5" runoff volume
ft3
Pre -development 1-yr, 24-hr runoff volume
ft3
Post -development 1-yr, 24-hr runoff volume
ft3
Minimum volume required
ft3
Volume provided
ft3
Outlet Design
Depth of temporary poollponding depth (DPIa,t,)
12.00 in OK
Drawdown time
2.32 days OK
Diameter of orifice
1.25 in OK
Coefficient of discharge (Ca) used in orifice diameter
0.60 (uniiless)
calculation
Driving head (Ho) used in the orifice diameter calculation
0.44 ft OK
Form SW401-Wetland-Rev.6-11116109 Parts I and 11, Project Design Summary, Page 1 or 3

Surface Areas of Wetland Zones
Surface Area of Entire Welland
5,563,00 ft'
OK
Shallow Land
2,247.00 ft'
Insufficient shallow land area.
The shallow land percentage is:
40% %
40 J ID
Shallow Water
2,187.00 ft2
OK
The shallow water percentage is:
39% %
Deep Pool
Forebay portion of deep pool (pretreatment)
541.00 ft'
Insufficient forebay area.
The forebay surface area percentage is:
10% %
Non-forebay portion of deep pool
588.00 ft2
OK
The non-forebay deep pool surface area percentage is:
11% %
Total of wetland zone areas
5,563.00 ft'
OK
Add or subtract the following area from the zones
0,00 ftZ
Topographic Zone Elevations
Temporary Pool Elevation (TPE)
Shallow Land (top)
680.00 ft amsl
Permanent Pool Elevation (PPE)
Shallow Water/Deep Pool (top)
680,00 ft amsl
Shallow Water bottom
679.50 ft amsl
Most shallow point of deep pool's bottom
678.00 ft amsl
Deepest point of deep pool's bottom
677.00 ft amsl
Design must meet one of the following two options:
This design meets Option #1,
(Y or N)
Top of PPE is within 6" of SHWT, If yes:
SHWT (Seasonally High Water Table)
it amsl
OK
This design meets Option #2,
Y' - (Y or N)
Wetland has liner with permeability < 0.01 in/hr, If yes:
Depth of topsoil above impermeable liner
12,00 in
OK
Topographic Zone Depths
Temporary Pool
Shallow Land
0.00 in
Permanent Pool
Shallow Water
6.00 in
OK
Deep Pool (shallowest)
24.00 in
OK
Deep Pool (deepest)
36.00 in
OK
Planting Plan
Are cattails included in the planting plan?
N (Y or N)
OK
Number of Plants recommended in Shallow Water Area:
Herbaceous (Ccubiinch container)
550
Number of Plants recommended in Shallow Land Area:
Herbaceous Wcubic-inch container), OR
600
Shrubs (1 gallon or larger), OR
96
Trees (3 gallon or larger) and Herbaceous (4+ cubic -inch)
12 and
480
Number of Plants provided in Shallow Water Area:
Herbaceous (4'cubic-inch container)
622
OK
Number of Plants provided in Shallow Land Area:
Herbaceous (4'cubic-inch container)
171
More required if not planting shrubs or trees.
Shrubs (1 gallon or larger)
61
More required if not planting herb. and/or trees.
Trees (3 gallon or larger) and
6
More required if not planting herb. and/or shrubs.
Grass -like Herbaceous (4+ cubic -inch)
Form SW401-Wetland-Rev.6-11116/09 Parts I and II. Project Design Summary, Page 2 of 3

Additional Information
Can the design volume be contained?
Y
(Y or N)
OK
Does project drain to SA waters? If yes,
N
(Y or N)
Excess volume must pass through filter.
What is the length of the vegetated filter?
ft
Are calculations for supporting the design volume provided in the
Y
(Y or N)
OK
application?
Is BMP sized to handle all runoff from ultimate build -out?
Y
(Y or N)
OK
Is the BMP located in a recorded drainage easement with a
Y
(Y or N)
OK
recorded access easement to a public Right of Way (ROW)?
The length to width ratio is:
1.58 :1
OK
Approximate wetland length
95,00 ft
Approximate wetland width
60.00 ft
Approximate surface area using length and width provided
5,700.00
ft'
This approx. surface area is within this number of square feet
of the entire wetland surface area reported above:
Will the wetland be stabilized within 14 days of construction?
Y
(Y or N)
OK
Form SW401-Wetland-Rev.6-11116109 Parts I and II. Project Design Summary, Page 3 of 3