SW6100601_401 Certification Application_20100625

Permit No. SW 6100&0
(to be pmvidetl by CUD)
®'\VY WA 9
i e
O� �G
NCDENR QU1Q
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
Project name Lot 2 Airport Commerce Park
Contact person
Phone number - Chris Millis, PE -
910.791-6707
Date 611012010
Drainage area number 1
II IOESIGN'INF0RMAT10Na';. ;'Y„ a:.«1,Ja+"!n'.
Site Characteristics
Drainage area 101.1710 e 1,r�
Impervious area, post -development - . 48,350 ft2 Su• M
%impervious 4779 % tp $
Design rainfall depth 1.0 in - }
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
Peak Flow Calculations
Is the Pre/post control of the 1yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre -development
Rational C, post -development
Rainfall intensity: 1-yr, 24-hr storm
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
PfelPost 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 10ft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
SedimenCcleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state -required temp. pool?
Elevation of the top of the additional volume
1 y��,
4,051 ft3 /OK '
7,873 ff3
It
ff3
fl3
ff3
ft3
N (Y or N)
rda in
nla limitless)
rda (uni0ess)
Na irdhr
nla ft3/sec
nla ff3/sec
#VALUE! ft3/sec
181.41 first
180.50 first
first
181..00 fmsl
180.00 fmsl
176.50 fmsl
175.50 fmsl
1.00 it
OK, volume provided is equal to or in excess of volume required.
y (Y or N)
-182.0 trust 4Bsnffi ' YaWered--
IV 0 =� 215e2 f�u�v�ri�rJ
Form SW401-Wet Detention Baaln-Rev.e-9117/09
Parts 1. 8 II. Design Summary. Page 1 or 2

Permit No.Slg) % 1 00 G 01
n0 beprovided by WO)
Surface Areast5'o-rr„4� t"r, rkd=
Area, temporary pool
Area REQUIRED, permanent pool
SAIDA ratio
Area PROVIDED, permanent pool, Ap,,,.
Area, bottom of 10ft vegetated shelf, Ate, ,,s,,
Area, sediment cleanout, top elevation (bottom of pond), A,_.
Volumes
Volume, temporary pool
Volume, permanent pool, Vn _,,
Volume, forebay (sum of forebays if more than one forebay)
Forebay %of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, Vim,,, via
Area provided, permanent pool, A._p,
Average depth calculated
Average depth used in SAIDA, d„, (Round to nearest 0,5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, A._,,
Area, bottom of 1Oft vegetated shelf, Ax(_wrn
Area, sediment cleanout, top elevation (bottom of pond), A,,.
"Depth" (distance bAv bottom of 100 shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, it., (Round to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if -non -circular)
Coefficient of discharge (Co)
Driving head (Ho)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre -development 1-yr. 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of Oowpath to width ratio
Length to width ratio
Trash rack for overflow 8 orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
5,544 ft2
2,924 ft2 ✓
2.89 (unilless)
✓
3,770 ft` ✓
OK
2,309 ft`
357 k2
7,873 ft3
OK
5,847 ft3
1,202 ft3
20.6% %
OK
90 %
N (Y or N)
Y (Y or N)
2.89 (unilless)
n (Y or N)
5,847 ft'
3,770 kr
ft --_46W44�
it
y (Y or N)
3,770 ft`
2,309 k2
357 ft2
3.50 It
k
3.0ft ✓
y (Y or N)
1.00 in
in
0.60 (unitless)
0.50 it
N (Y or N)
limitless)
limitless)
R
it
0.02 ft3/sec
1.36 ft3/sec
0.02 ft3/sec /
OK, draws down in 2-5 days.
2.50 days
3 :1- •-'
OK
10 :1
OK
10.0 ft
OK
3:1
OK
3.0 :1
OK
y (Y or N)
OK .
2.5ft
OK
n (Y or N)
OK
y. (Y or N)
OK
y (Y or N)
OK
Pump Out
Form S W401-Wet Detention Basin -Rev B-9117/09
Pans I. S 11. Design Summary. Page 2 of 2

Permit No. �AA(o100(001
(to be provided by DWQ)
III'.REQUIRED:ITEMS;CHECKLISTi�',Atttk
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.
66A—
G_3,0
1. Plans (1" - 50' or larger) of the entire site showing:
6-3• IDA-
✓ Design at ultimate build -out,
✓- Off -site drainage (if applicable),
✓- Delineated drainage basins (include&atienetGeaeffreientper basin), USLD _ J)(tLS ( � AA
✓- Basin dimensions, ( AI W SGF#nI�)
✓- Pretreatment system,
High flow bypass system,
-
✓Maintenance access,
✓- Proposed drainage easement and public right of way (ROW),
✓- Overflow device, and
Boundaries of drainage easement.
C-3 D
2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
C_ 3. 0/1
✓- Outlet structure with trash rack or similar,
C_ S. 0 _
✓- Maintenance access,
J �
✓- Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
✓- Basin cross-section,
✓- Vegetation specification for planting shelf, and
Filter strip.
C� h
C—S• 1
3. Section view of the wet detention basin (1" = 20' or larger) showing:
✓Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
✓Inlet and outlet structures.
4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
CW
G/a 1 C S
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
C NH
C' j 0
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
C y
CR1G
7. The supporting calculations.
CH ✓ 1
8. A copy of the signed and notarized operation and maintenance (08M) agreement.
C ✓YV
9. A copy of the deed restrictions (if required).
01A 0�4 10. A soils report that is based upon an actual field investigation, soil borings, and inf Itradon tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Part III. Required Items Checklist, Paget of 1