SW6140302_Supplement_20140424

N17nr�rrr Permit No.
it w'e _r4. (ro be provided by D WD)
�\ 11
0Q=�2�(7V�J�452
dji'•Pjo2pF WA7cROC
NCDENR
0..0....
STORMWATER MANAGEMENT PEQT'APPr QJION ORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This tom must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted skmg with all ofthe required information.
I!. PROJECT INFORMATION
Project name
West Hampton Phase II
Contact person
Scott Brown
Phone number
910-426-6777 ext. 102 _
Date
2J3I2014 -
Drainage area number
1
III DESIGNIINFORMATION'.
Site Characteristics
Drainage area 1,157,130 ii
Impervious area, post -development 356,178 ft2
%impervious 30.78 %
Design rainfall depth 1.0 in
Storage Volume: Non -SA Waters
Minimum volume required 31,768 fts
Volume provided
51,950 ftr
OK, volume provided is equal to or in excess of volume required.
Storage Volume: SAWaters
1.5'runoff volume
fts
-- - ---- - -
Pre -development 1-yr, 24-hr runoff
it
Post -development 1-yr, 24-hr runoff
ft3
Minimum volume required
it
I
I OCT 16 2014 �
Volume provided
fts
Peak Flow Calculations
Is the pre/post control of the 1 yr 24hr storm peak flow required?
Y (Y or N)
1-yr, 24-hr rainfall depth
3.0 in
_ ' _GE _ 1
Rational C, pre -development
0.30 (unidess)
-
Rational C, post -development
0.52 (unitess)
/-� Z _U
Rainfall intensity: l-yr, 24-hr storm
Pre -development 1-yr,224hr peak bow
0.13 inthr
.ftslsec
OK U
Post -development 1-yr, 224hr peak flow
0 .3939 ft'Isec
Pre/Post 1-yr, 24-hr peak flow control
-0.65 ftslsec
(]
Elevations
Temporary pool elevation -
101.20 fmsl
Permanent pool elevation
99.10 fmsl
SHWT elevation (approx. at the pen. pool elevation)
99.57 fmsl
Top of 10ft vegetated shelf elevation
99.60 fmsl
Bottom of 10ft vegetated shelf elevation
98.60 fmsl
Data not needed for calculation option #1, but OK if provided.
Sediment deanout, top elevation (bottom of pond)
94.10 fmsl
Sediment Geanout, bottom elevation
93.10 fmsl
Data not needed for calculation option #1, but OK if provided.
Sediment storage provided
1.00 it
Is there additional volume stored above the state -required temp. pool?
Y (Y or N)
Elevation of the top of the additional volume
101.2 fmsl
OK
Form SW401-Wet Detention Basir,Rev.9-4/18/12
Parts I. S II. Design Summary, Page 1 of 2

Permit
(fo be povided by DM)
II!, DESIGMINFORMATION
Surface Areas
Area, temporary pool
25,593 ftr
Area REQUIRED, permanent pod
20,018 It
SAIDA ratio
1.73 (unithm)
Area PROVIDED, permanent pool, A�,,,y d
20,065 ft`
OK
Area, bottom of 1 OR vegetated shelf, A a, �,�
16,839 ft`
Area, sediment deanout, top elevation (bottom of pond), A,.,e
8,936 fe
Volumes
Volume, temporary pool
51,950 fta
OK
Volume, permanent pool, Vpa _,a,,
79,625 ft'
Volume, forebay, (sum of forebays if more than one fombay)
14,354 ft"
Forebay % of permanent pool volume
18.0% %
OK
SAIDA Table Data
Design TSS removal
90 %
Coastal SAIDA Table Used?
Y (Y or N)
Mountain/Piedmont SAIDA Table Used?
N (Y or N)
SAIDA ratio
1.73 (unifiess)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Y (Y or N)
Volume, permanent pod, Vp _,,y
79,625 ft'
Area provided, permanent pool, A _,d
20,065 ft
Average depth calculated
3.00 If
OK
Average depth used in SAIDA, d., (Round to nearest 0.5ft)
3.0 ft
OK
Calculation option 2 used? (See Figure 10-2b)
N (Y or N)
Area provided, permanent pod, Ap,.
20,065 ft/
Area, bottom of tOft vegetated shelf, Ae mer
16,839 ft'
Area, sediment deanout, top elevation (bottom of pond), Abya.4
8,936 ft'
'Depth' (distance btw bottom of 1 Oft shelf and top of sediment)
4.50 ft
Average depth calculated
ft
Average depth used in SAIDA, d,V, (Round to down to nearest 0.511)
It
Drawdown Calculations
Drawdown through orifice?
Y (Y or N)
Diameter of orifice (if circular)
3.25 in
Area of orifice (ff-non-circular)
in'
Coefficient of discharge (Cc)
0.60 (unit ess)
Driving head (Hj
0.00 it
Drawdown through weir!
N (Y or N)
Weirtype
(unifless)
Coefficient of discharge (C„)
(unittess)
Length of weir (L)
it
Driving head (H)
ft
Pre -development 1-yr, 24-hr peak flow
1.04 ftalsec
Post -development 1-yr, 24-hr peak flow
0.39 ft'/sec
Stooge volume discharge rate (through discharge orifice or weir)
0.23 fl3lsac
Storage volume drawdown fire
2.60 days
OK, draws down in 25 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 it
OK
Length of towpath to width ratio
3 :1
OK
Length to width ratio
3.0 :1
OK
Trash rack for overflow & orifice?
Y (Y or N)
OK
Freeboard provided
1.2 ft
OK
Vegetated filter provided?
N (Y or N)
OK
Recorded drainage easement provided?
Y (Y or N)
OK
Captives all runoff at ultimate build -out?
Y (Y or N)
OK
Drain mechanism for maintenance or emergencies is:
PUMP OUT
Fonn SW401-Wet Detention Basin-Rev.9-4/18/12 Parts I. & II. Design summary, Page 2 of 2

Permit No.
(to be Provided by DWQ)
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.
C 3.0 4 >
1. Plans (1"- 50' or larger) of the entire site showing:
3•q
Design at ultimate build -out,
Off -site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW),
- Overflow device, and
- Boundaries of drainage easement.
S R
C 3�- 3.9
2. Partial plan (1" = 30' or larger) and details for the wet detention basin shoving:
(LS't�-S 17
- Outlet structure with trash rack or similar,
- Maintenance access,
- Permanent pool dimensions,
- Forebay and main pond with hardened emergency spillway,
- Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
513
^^
l` S. 14
3. Section view of the wet detention basin (1" = 20' or larger) showing:
S / 7
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
S13—J•$�
3.9
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.
513
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
5 r3
3. D
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
5 t3
0AU S
7. The supporting calculations.
Si3
f U05
&, A copy of the signed and notarized operation and maintenance (O&M) agreement.
S IS
MC CS
g A copy of the deed restrictions (if required).
SL7 Q Q� PS 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.9-4/19/12 Part III. Required Items Checklist, Page 1 of 1

Permit No.
/to ee provided by Dw0)
SEAL
027452
0
NCDENR
b / I
`01
STORM WATER MANAGEMENT PERMIT APPLICATION FORM i' o
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
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.
Project name
Contact person
Phone number
Dale
Drainage area number
Scatt Brown
910426-6777 ext. 102
II. DESIGN INFORMATION
Site Characteristics
Drainage area 441,212 if
Impervious area, post -development 134,087 f?
%impervious 30.39 %
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-hp runoff
Post -development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1 yr 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
Pre.IPost 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 deanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state -required temp. pool?
Elevation of the lop of the additional volume
o2�F 10ATEg0G
y T
O T
11,732 ft3
12,368 ft3
OK, volume provided is equal to or in excess of volume required.
ft3
it,
ft3-
ft3 ,
It
Y (Y or N)
3.0 in
0.30 (unidess)
0.50 (unidess)
0.13 inmr OK
0.39 ft3lsec
0.09 ft3/sec
-0.30 ft3/sac
112.71 fmsl
111.50 fmsl
111.94 lnisl
112.00 first
111.00 fmsl
106.50 fmsl
105.50 Irnsl
1.00 It
(Y or N)
112.7 fmsl
OCT 16 ?C.•:
Data not needed for calculation option #1, but OK if provided.
Data not needed for calculation option #1, but OK if provided.
OK
Forth SW401-Wet Detention Basin-Rev.g-4/18A2 Pans 1. S 11. Design Summary, Page 1 of 2

-j,"
.;
Permit
(to be Provided 0y DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool
11,855 ft3
Area REQUIRED, permanent pool
8,383 ft
SAIDA ratio
1.90 (unitless)
Area PROVIDED, permanent pool, A�
8,491 ft
OK
_pw
Area, bottom of 1 Oft vegetated shelf, A, uon
6,619 ft
Area, sediment cleanout, top elevation (bottom of pond), A. �a
2,359 ft
Volumes
Volume, temporary pool
12,368 ft3
OK
Volume, permanent pool, Va,,,,.
25,011 ft'
Volume, forebay (sum of forebays if more than one forebay)
4,520 ft'
forebay %of permanent pool volume
18.1% %
OK
SAIDA Table Data
Design TSS removal
90 %
Coastal SAIDA Table Used?
Y (Y or N)
MountairVPiedmont SAIDA Table Used?
N (Y or N)
SAIDA ratio
1.90 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Y (Y or N)
Volume, permanent pool, Vim,,, .
25,011 ft3
Area provided, permanent pool, A._.
8,491 ft
Average depth calculated
3.00 ft
OK
Average depth used in SAIDA, d., (Round to nearest 0.511)
3.0 it
OK
Calculation option 2 used? (See Figure 10-2b)
N (Y or N)
Area provided, permanent pool, Ate,,,,
8,491 ft'
Area, bottom of 10ft vegetated shelf, A,ua,
6,619 fh
Area, sediment cleanout, top elevation (bottom of pond), Ay,.
2,359 e
'Depth' (distance blw bottom of 1Oft shelf and top of sediment)
4.50 it
Average depth calculated
it
Average depth used in SAIDA, J., (Round to down to nearest 05ft)
It
Drawdown Calculations
Dmwdown through orifice?
Y (Y or N)
Diameter of orifice (d circular)
1.75 in
Area of orifice (if-noncircular)
in
Coefficient of discharge (CD)
0.60 (unitless)
Driving head (Ho)
0.40 ft
Dmwdown thmugh weir/
N (Y or N)
Weir type
(unitless)
Coefficient of discharge (C„)
(uni8ess)
Length of weir (L)
ft
Driving head (H)
ft
Pre -development 1-yr, 24-hr peak flow
0.39 ft3/sec
Post -development 1-yr, 24-hr peak flow
0.09 ft3/sec
Storage volume discharge rate (through discharge orifice or weir)
0.05 ft3ISec
Storage volume drawdown time
2.80 days
OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes
3 :1
OK
Vegetated shelf slope
10 :1
OK
Vegetated shelf width
10.0 ft
OK
Length of flowpath to width ratio
3 :1
OK
Length to width ratio
2.0 :1
OK
Trash rack for overflow & onfce?
Y
(Y or N)
OK
Freeboard provided
2.3 ft
OK
Vegetated filter provided?
N
(Y or N)
OK
Recorded drainage easement provided?
Y
(Y or N)
OK
Capures all runoff at ultimate build -out?
Y
(Y or N)
OK
Drain mechanism for maintenance or emergencies is:
PUMP OUT
Forth SW401-Wet Detention Basin-Rev.94/18/12
Parts I. & II. Design Summary, Page 2 of 2

Permit No.
(to be provided by DWQ)
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.
s�
(-3• D �0
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),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROM,
Overflow device, and
Boundaries of drainage easement.
S3
C 7,8 - 39
2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
- Vegetation specification for planting shelf, and
- Filter strip.
S" /6
3. Section view of the wet detention basin (1" = 20' or larger) showing:
Z 7
- Side slopes, 3:1 or lower,
- Pretreatment and treatment areas, and
- Inlet and outlet structures.
58
0-3.8-7.9
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.
S8
SAC e5
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for Forebay,
to verify volume provided.
S 3
(AL(s
6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
S B
"11e5
7. The supporting calculations.
5/3
(A/CS
8. A copy of the signed and notarized operation and maintenance (O&M) agreement.
53
U/es
9. A copy of the deed restrictions (if required).
Sf3 �4LCS 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.94/18/12 Pan III. Required Items Checklist, Page 1 of 1

Permit No.
• - (to be provided by DWQ)
o201C WA TF9OG
NCDENR o�<
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.
I. PROJECT INFORMATION'.
Project name
West Hampton Phase II
Contact person
Scott Broom
Phone number
910-426-6777 ext. 102
Date
2/3/2014
Drainage area number
1
II!. DESIGN; INFORMATIONI
- - - -
Site Characteristics
Drainage area
1,157,130 ft°
Impervious area, post -development
356,178 ft'
%impervious
30.78 %
Design rainfall depth
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 prelposl control of the tyr 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
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWr elevation (approx. at the perm. pool elevation)
Top of 1011 vegetated shelf elevation
Bottom of 10ft vegetated shelf elevation
Sediment deanout, top elevation (bottom of pond)
Sediment deanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state -required temp, pool?
Elevation of the top of the additional volume
1.0 in
31,768 ft3
52,135 ft3
OK, volume provided is equal to or in excess of volume required.
It
Y , (Y or N)
3.0 in
0.30 (unrtless)
0.52 (uniUess)
0.13 m/hr OK
1.04 ft3/sec
0.39 ft3/sec
-0.65 ft'/sec
OCT 1 6 C
101.18 fmsl
99.10 fmsl
99.57 fmsl
99.60 fmsl
98.60 Imsl Data not needed for calculation option #1, but OK if provided.
94.10 fmsl
93.10 trust Data not needed for calculation option 411, but OK 8 provided.
1.00 it
Y (Y or N)
101.2 hnsl OK
Feral SW401-Wet Detention Basin-Rev.9-4118112 Parts I. & It. Design Summary, Pape 1 of 2

Permit No.
(b be pmmW by DWD)
Il..DESIGN ..INFORMATIONL....
Surface Areas
Area, temporary pool 27,055 ft'
Area REQUIRED, permanent pool
17,820 ftz
SAIDA ratio
1.54 (unitless)
Area PROVIDED, permanent pool, Ap,,,, cad
21,032 ft`
OK
Area, bottom of 1 Oft vegetated shelf, A,,N.
18,195 ft`
Area, sediment cleanout, top elevation (bottom of pond), Aw,y
9,477 ft`
Volumes
Volume, temporary pool
52,135 ft'
OK
Volume, permanent pool, Vy,,,,ym
68,311 ft'
Volume, forebay (sum of forebays ff more than one forebay)
14,445 ft'
Forebay %of permanent pool volume
21.1% %
OK
SAIDA Table Data
Design TSS removal
90 %
Coastal SAIDA Table Used?
Y (Y or N)
Mountain/Piedmont SAIDA Table Used?
N (Y or N)
SAIDA redo
1.54 (unidess)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Y (Y or N)
Volume, permanent pool, Vp,, ,,
68,311 ft'
Area provided, permanent pool, Ap,.,r,"
21,032 ft`
Average depth calculated
4.40 it
OK
Average depth used in SAIDA, d„, (Round to nearest 0.5ft)
4.5 It
OK
Calculation option 2 used? (See Figure 10-21h)
N (Y or N)
Area provided, permanent pool, Ao _p,
21,032 ft`
Area, bottom of 1Oft vegetated shelf, A, -a
18,195 ft
Area, sediment cleanout, top elevation (bottom of pond), Ay_,,
9,477 ft
'Depth" (distance b/w bottom of 10ft shelf and lop of sediment)
4.50 ft
Average depth calculated
ft
Average depth used in SAIDA, it.., (Round to down to nearest 0.5ft)
It
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of office (if-non-arcular)
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 i-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 flowpath 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:
Y (Y or N)
3.25 in
in'
0.60 (unless)
0.00 ft
N (Y or N)
(unless)
(unitless)
ft
ft
1.04 ft'/sec
0.39 ft3/sec
0.23 ft'/sec
2.60 days
3 :1
10 :1
10.0 If
3a
3.0 :1
Y
(Y or N)
1.4 ft
N
(Y or N)
Y
(Y or N)
Y
(Y or N)
PUMP OUT
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
OK
OK
OK
Of
Form SW401-Wet Detention Basio-Rev.9-M78112
Paris I, a II. Design Summary, Page 2 of 2

j, Permit No.
. (b be provided by DWD)
o2pf W AT -;
S
NCDENR
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 (Pad 111) must be printed, filled out and submitted along with ell of the required information.
I. PROJECT INFORMATIONi
Project name
West Hampton Phase II
Contact person
Scoft Bro m
Phone number
910-426-6777 ext. 102
Date
2/3/2014
Drainage area number
1
11 DESIGN INFORMATION
Site Characteristics
Drainage area
441,212 ft'
Impervious area, post -development
134,087 g2
%impervious
30.39 %
Design rainfall depth
1.0 in
Storage Volume: Non-SAWaters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5' mnog volume
Pre -development l-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
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SH WT elevation (approx. at the perm. pool elevation)
Top of 1011 vegetated shelf elevation
Bottom of 1011 vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment deanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state -required temp. pool?
Elevation of the top of the additional volume
11,732 ft3
12,368 it'
OK, volume provided is equal to or in excess of volume required,
ft3
it
ft3
ft3
ft3
OCT 16
Y (Y or N)
3.0 in
0.30 (unitless)
0.50 (unifless)
0.13 in/hr OK
0.39 ft3/sec
0.09 ft3/sec
-0.30 ff3kcr.
112.71 hnsl
111.50 first
111.94 mist
112.00 first
111.00 fmsl Data not needed for calculation option Ill, but OK if provided.
106.50 fmsl
105.50 fmsl Data not needed for calculation option 1t1, but OK if provided.
1.00 it
Y (Y or N)
112.7 bnsl OK
Form SW401-Wet Detention Basin-Rev.9-4/1e/12 Pans I. 311. Design Summary, Page 1 of 2

Permit No.
fro be provided by DWD)
Ib, DESIGN!JNFORMATIONI
Surface Areas
Area, temporary pool
Area REQUIRED, permanent pod
SAIDA ratio
Area PROVIDED, permanent pool, Ap,, w
Area, bottom of 10ft vegetated shelf, A..,,,,
Area, sediment deanout, top elevation (bottom of pond), A,.,
Volumes
11,855 ft
8,383 ft
1.90 (unitless)
8,491 ft OK
6,619 ft
2,359 ft
Volume, temporary pod 12,368 ft3
Volume, permanent pod, Vp,,,, cm 25,011 fts
Volume, fombay (sum of forebays 8 more than one tomboy) 4,520 ft3
Forebay % of permanent pool volume 18.1 % %
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
MountairvPiedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-21h)
Volume, permanent pool, V._P,
Area provided, permanent pool, Ap,,,, w
Average depth calculated
Average depth used in SAIDA, dn., (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, Ap,,,,y
Area, bottom of 1Oft vegetated shelf, A,,ran
90 %
Y (Y or N)
N (Y or N)
1.90 (unidess)
OK
OK
Y (Y or N)
25,011 ft3
B,491 f?
3.00 If OK
3.Oft OK
N (Y or N)
8,491 fe
6,619 ft
Area, sediment deari top elevation (bottom of pond), A,. 2,359 fe
'Depth' (distance btw bottom of 1 Oft shelf and top of sediment) 4.50 ft
Average depth calculated It
Average depth used in SAIDA, d,., (Round to down to nearest 0.5ft) It
Drawdown Calculations
Drawdown through orfice?
Diameter of orifice (if circular)
Area of orifice (if -non -circular)
Coefficient of discharge (CD)
Driving head (Ha)
Drawdown through weir?
Weirtype
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 towpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated fifer provided?
Recorded drainage easement provided?
Capures all runoff at ultimate buildout?
Drain mechanism for maintenance or emergencies is:
Y (Y or N)
1.75 in
in7
0.60 (unidess)
0.40 It
N (Y or N)
(unidess)
limitless)
It
It
0.39 ft3/sec
0.09 ft3/sec
0.05 fts/sec
2.80 days
3 :1
10 :1
10.0 It
3a
2.0 a
Y
(Y or N)
2.3 It
N
(Y or N)
Y
(Y or N)
Y
(Y or N)
PUMP OUT
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Form SW401-Wet Detention Basir-Ray.9-4/1B/f2 Pans 1. & It. Design Summary, Page 2 of 2

I 's'
Permit
(to be provided by
NCDENR
SEAC f
027452 -
%C "'-AfG,INEE 0, 'I� I o2�F WA7EAo
*Q ,f� 0
STORMWA EC CERTIFICATION APPLICATION f'ORM' ' �M
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Pad 111) most be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name West Hampton Phase II
Contact person Scott Brown
Phone number 910-426-6777 ext. 102
Date 2/3/2014
Drainage area number 1
II. DESIGN INFORMATION
Site Characteristics
- - --
Drainagearea
1,157,130 e -
Impervious area, post development
356,178 112 - r
%impervious
30.78 %
Design rainfall depth
1.0 in -
OCT 16
Storage Volume: Non -SA Waters
Minimum volume required
31,768 ft3
Volume provided
52,135 Its
Of, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5' mnoff 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-hrstorm
Pre -development 1-yr, 24-hr peak flow
Post -development 1-yr, 24-hr peak flow
Pre/Post 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 10ft vegetated shelf elevation
Sediment deanout, top elevation (bottom of pond)
Sediment cleanoul, bottom elevation
Sediment storage provided
Is there additional volume stored above the state -required temp. pool?
Elevation of the top of the additional volume
ft3
ft3
Y (Y or N)
3.0 in
0.30 (unitless)
0.52 (unitless)
0.13 inRu OK
1.04 ft3lsec
0.39 ft3lsec
-0.65 ft3lsec
101.18 fmsl
99.10 fmsl
99.57 fmsl
99.60 fmsl
98.60 fmsl
94.10 tryst
93.10 fmsl
1.00 It
APR 2 1 2014
Data not needed for calculation option #1, but OK if provided.
Data not needed for calculation option #1, but OK if provided.
Y (Y or N)
101.2 fmsl OK
Forth SW401-Wet Detention Basin -Rev 9-4118/12 Parts I. S 11. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWO)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool
Area REQUIRED, permanent pool
SAIDA ratio
Area PROVIDED, permanent pool, An, .
Area, bottom of 1 Oft vegetated shelf, A. vie,
Area, sediment cleanout, top elevation (bottom of pond), A.y re„
Volumes
27,055 it'
17,820 fl
1.54 (unitless)
21,032 ft? OK
18,195 ftz
9,477 It'
Volume, temporary pool
52,135 ft'
Volume, permanent pool, Vo,,,, r,
68,311 ft3
Volume, forebay (sum of forebays if more than one forebay)
14,445 ft3
Forebay %of permanent pool volume
21.1% %
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
MountairVPiedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, Vim,,, ,
Area provided, permanent pool, A._,,
Average depth calculated
Average depth used in SAIDA, da,., (Round to nearest 0.511
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, A.-.
Area, bottom of 1 Oft vegetated shelf, Aw g�
90 %
Y (Y or N)
N (Y or N)
1.54 (unitless)
Y (Y or N)
68,311 ft3
21,032 Ile
4.40 it
4.5 it
N (Y or N)
21,032 ft
18,195 ft
Area, sediment deanout, top elevation (bottom of pond), A,., 9,477 11
'Depth' (distance btw bottom of 1Oft shelf and top of sediment) 4.50 it
Average depth calculated it
Average depth used in SAIDA, d., (Round to down to nearest 0.511) ft
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if -non -circular)
Coefficient of discharge (Cu)
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 Impart to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build -out?
Drain mechanism for maintenance or emergencies is:
Y (Y or N)
3.25 in
in
0.60 (unitless)
0.00 It
N (Y or N)
(unitless)
(unitless)
it
ft
1.04 ft3/sec
0.39 ft3/sec
0.23 ft3/sec
2.60 days
3 :1
10 :1
10.0 it
3 :1
3.0 :1
Y
(Y or N)
1.4 It
N
(Y or N)
Y
(Y or N)
Y
(Y or N)
PUMP OUT
OK
OK
OK
OK
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
Form SW401-Wel Detention Basin -Rev 9-4/ia/12 Parts I. & ll. Design Summary, Page 2 of 2