SW8021024_COMPLIANCE_20030110

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW_�v�./Do�'�-f
DOC TYPE
❑CURRENT PERMIT
❑ APPROVED PLANS
❑ HISTORICAL FILE
COMPLIANCE EVALUATION INSPECTION
DOC DATE
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DETENTION POND ANALYSIS FILE NAME: G:IDATAIWPDATAIWQSIPOND1021024-2.WK1
PROJECT #: SW8 021024-2 Pond 2 , REVIEWER: L. Lewis
PROJECT NAME: Farmstead Subdivision Section I
DATE: 10-Jan-03
Receiving Stream: Hickmans Branch Class: C Sw
Drainage Basin: Lumber Index No. LBR57 15-23-3
Site Area 312.25 acres
Drainage Area 3025; square feet Area = 6.96 acres
IMPERVIOUS AREAS
Lots
Street
TOTAL
SURFACE AREA CALCULATION
% IMPERVIOUS 42.28%
Des. Depth 6
TSS: 90
Rational C
91000.00 square feet
37248.00 square feet
square feet
square feet
square feet
square feet
28248 40 square feet
Rational Cc= 0,12
SAIDA Ratio 2.24%
Req. SA 6785 sf
Prov. SA 60'8 sf
VOLUME CALCULATION * place a "1" in the box if Rational is used
Rational ?*
Des. Storm
:1..:QO:<
in
Rv=
0.43
Bottom
25 msl
Perm. Poo!
31.0 msl
Design Pool
32.5 msl
Design SA
8634 sf
Req. Volume
::; 1088
cf
Prov. Volume
_ _ _ ..:::.<.;:1::1:69<
cf
ORIFICE CALCULATION
Avg. Head =
Flow Q2, cfs
Flow Q5, cfs
No. of Orifices
Diameter, inches
Drawdown =
•C 1
Perm. Pool Volume= 13457
Req. Forebay Volume= 2691.4
Provided Volume= 2641.00
Percent= 96°lfl
SA @ _
Elevation=
0.72
ft
Q2 Area =
0.063
cfs
Q5 Area =
0.025
cfs
Orifice Area
>'7<
Q=
weir H x W
days
COMMENTS
Surface Area , Volume and Orifice are within Design GuidelineE
in
2.22 sq. in.
0.89 sq. in.
1.77 sq. in.
0.050 cfs
x FFTT
in

DETENTION POND ANALYSIS FILE NAME: G:IDATAIWPDATAIWQSIPOND1021024-1.WK1
PROJECT #: SW8 021024-1 Pond 1 REVIEWER: L. Lewis
PROJECT NAME: Farmstead Subdivision Section I
DATE: 10-Jan-03
Receiving Stream: Hickmans Branch Class: C Sw
Drainage Basin: Lumber Index No. LBR57 15-23-3
Site Area 31 2. 25 acres
Drainage Area 1721 Q square feet Area = 3.94 acres
IMPERVIOUS AREAS
Rational C
Lots 56668.00 square feet
Street 38863.00 square feet
square feet
square feet
square feet
square feet
TOTAL 931< p0' square feet Rational Cc= 0.09
SURFACE AREA CALCULATION
IMPERVIOUS
55.63%
SA/DA Ratio
3.09%
Des. Depth
6
Req. SA
5313 sf
TSS:
90
Prov. SA
5622. sf
VOLUME CALCULATION
Rational ?"
Des. Storm
::<:>::>1':>4'':
---..........
inches
Rv=
0.55
Bottom
24 msl
Perm. Pool
........ 30 GG msl
Design Pool
31.4 msl
Design SA
7047 sf
Req. Volume
784
cf
Prov. Volume
cf
ORIFICE CALCULATION
Avg. Head =
Flow Q2, cfs
Flow Q5, cfs
No. of Orifices
Diameter, inches
Drawdown =
0.67 ft
0.046 cfs
0.018 cfs
weir HxW
days
* place a " T' in the box if Rational is used
FOREBAY
Perm. Pool Volume=
Req. Forebay Volume=
Provided Volume=
Percent=
SA @ _
Elevation=
9749
1949.8
1952,00
20-.0
Q2 Area =
1.66
sq. in.
Q5 Area =
0.66
sq. in.
Orifice Area
1.23
sq. in.
Q=
0.034
cfs
in
x
COMMENTS
Surface Area , Volume and Orifice are within Design Guideline:
in

CURB AND GUTTER ANALYSIS
PROJECT NUMBER:
PROJECT NAME:
RECEIVING STREAM
DRAINAGE BASIN:
021024
Farmstead Section I
Hickmans Branch
Lumber
A= BY+MY
P= B + 2Y (1 + MA2)A&5
R= A/P
FILE: G:IDATAIWPDATAIWQSIC&G1021024
DATE: 10-Jan-03
CLASS: C Sw
INDEX: LBR5715-23-3
i, in/hr= 7
n= 0.027
M= 5
FLOWRATE I VELOCITY COMPUTATION
Q=CiA
<=.05
V=Q/A
Swale #
DA
BUA
C
Q
Slope
Velocity
acres
acres
cfs I
Lft/�
(fps)
1
1.02
0.42
0.52
3.72
0.005
1.63
2
0.55
0.46
0.85
3.28
0.005
1.63
3
0.87
0.67
0.80
4.88
0.01
2.22
4
1.15
0.69
0.67
5.38
0.01
2.36
5
#DIV/O!
#DIV/O!
#DIV/01
6
#DIV101
#DIV/01
#DIV/O!
7
#DIV/O!
#DIV/01
#DIV/O!
8
#DIV/O!
#DIV/O!
#DIV/O!
9
#DIV/O!
#DIV/O!
#DIV/O!
10
`
#DIV/O!
#DIV/O!
#DIV/O!
NORMAL DEPTH COMPUTATION
SWALE #
B
Y
A
P
R
Zav
Zreq
1
5
0.34
2.28
8.47
0.27
0.95
0.95
2
4
0.35
2.01
7.57
0.27
0.83
0.84
3
5.
0.33
2.19
8.37
0.26
0.90
0.88
4
5
0.34
2.28
8.47
0.27
0.95
0.97
5
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
6
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
7
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
8
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
9
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
10
0.00
0.00
#DIV/O!
#DIV/O!
#DIV/O!
GRASS COVER SPECIFIED ON PLANS:
Bermuda and Bahia
ALLOWABLE VELOCITY, fps, for slopes 0%-5%, easily erodible soil:
Bermuda 5 Bluegrass 4.5
Fescue 4.5 Legume 3.5
Bahia 4.5
COMMENTS

FARMSTEAD
SECTION I
BRUNSWICK COUNTY, NC
STOR.MWATER & EROSION CONTROL
CALCULATIONS
FOR
SITE DEVELOPMENT
September 2002 RECEIVED
2.2 2002
DWQ
PROJ # SG f 02100 4-
Prepared by:
East Coast
Engineering Company, P.A.
Consulting Engineers
Shallotte, North Carolina 28459
Post Office Box 2469 1918 Main Street
Office: 910.7 i4.8029

Farmstead Section 1
Catch Basin Curb Cut
Calculations
-Q to'CC-1 from DA-1
SWALE
Q to CB-2 from DA-3
Q to CB-4 from DA-5
DA S jr o
East Coast Engineering Company, PA
DAH
Drainage Area =
44,535
SF
Q to CB-1 from DA-2
Drainage Area =
42,795
SF
Drainage Area =
1,02
Acres
Drainage Area =
0.98
Acres
Design Storm =
25
YR storm
Design Storm =
25
-YR storm
Surface
Acres
C-Valuer'}
Surface
Acres
C-Value r11
AsphaiuRooftop
0.4151
0.95
�► }
Asphalt/Rooftop
0.5278
0.95
Grass
0.61
0.2
l/
Grass
0.45
0.2
Total A'
1.0224
�0�
Total 'A'
0.98
Weighted 'C'
0.504496
Weighted 'C'
0.602927
Tc Length
460
To Length
320
To High Elev.
38.8
Tc High Elev.
36.5
To Low Elev.
35.86
To Low Elev.
34.51
Slope
0,0064
Slope
0.0062
Tc
6.13
To
4.68
To Factor (2)
0.4
To Factor (2)
0.4
To w/ Factor
2.4509
Tc wl Factor
1.873
Intensity ' i ' (3)
8
Intensity ' i ' (3)
8
Q; = C iA
4.1263
cfs
Qi = CIA
4.7387
cfs
Drainage Area =
29,970
SF
Q to CB-3 from DA-4
Drainage Area =M25
SF
Drainage Area =
0.69
Acres
Drainage Area =
Acres
Design Storm =
25
-YR storm
Design Storm =-YR
storm
Surface
Acres
C- Value f}i
Surface
Acres
C-Value r1
Asphalt/Rooftop
0.5268
0.95
Asphalt/Rooftop
0,5742
0.95
Grass
0.16
0.2
1
Grass
0.83
0.2
Total 'A'
0.688
1
Tote A'
1.4025
Weighted 'C'
0.774249
[�
Weighted 'C'
0.507044
Tc Length
320
Tc Length
330
Tc High Elev.
36.5
Tc High Elev,
35.53
To Low Elev,
34,51
Tc Low Efev.
33,71
Slope
0.0062
Slope
0.0055
To
4.68
Tc
5,02
Tc Factor (2(
0.4
Tc Factor (2)
0.4
Tc w/ Factor
1.873
To wl Factor
2.0087
Intensity'i'(3)
7.1
Intensity ' i,(3)
8
Qi = C iA
3.7821
cfs.
Q; = CrA
5.6$9
cfs
Drainage Area =
Drainage Area =
37,863
0.87
SF
Acres
f _
C2,io.CC-2 from DA-B
SWALE
Drainage Area =
Drainage Area =
F2-3-,9-811
SF
Acres
1 0.55
Design Storm =
25
-YR storm
Design Storm =
L25
-YR storm
Surface
Acres
C-Value r11
Surface
Acres
C-Value r1i
Asphalt/Rooftop
0.5643
0.95
Asphalt/Rooftop
0.4601
0.95
Grass
0.30
0.2
Grass
0,09
0.2
Total A'
0.8692
Total 'A'
0.5505
Weighted 'C'
0.686927
Weighted 'C'
0.82684
To Length
330
Tc Length
250
Tc High Elev.
35.53
Tc High Elev.
35.53
Tc Low Elev.
33.71
To Low Elev,
33,77
Slope
0.0055
Slope
0.007
Tc
5,02
To
3,69
To Factor (2)
0.4
Tc Factor (z(
0.4
Tc wl Factor
2.0087
Tc w/ Factor
1.4766
Intensity ' i ' (3)
8
Intensity ' i ' (3)
8
Qi = C iA
4.7767
cfs
Qi = C to
3.6416
cfs
(1) Table 8.03a; (2) Figure 8.03a; (3) Figure 8.03b of the NCDENR Erosion and Sediment Control Planning and Design Manual. Ravi$ion Date: 9116102

Farmstead Section 1
East Coast Engineering Company, PA
Catch Basin Curb Cut
DAH
Calculations
rQ'to"CC-3-from �DA
Drainage Area =
37,895
SF
Q to CB-5 from DA-8
Drainage Area =
52,139 SF
SWALE��
Drainage Area =
0.87 1
Acres
Drainage Area =
1.20 Acres
Design Storm =
Surface
25
-YR storm
C-Value "t
Design Storm =
Surface
25 -YR storm
Acres C- Value lr1
Acres
Asphalt/Rocftop
0.6733
0.95
Asphalt/Rooftop
0.5724
0.95
Grass
0.20
0.2
Grass
0.62
0.2
Total 'A'
0.8699
P�(1
C
Total 'A'
1.1969
Weighted 'C'
0. 804461,
Weighted 'C'
0.558637
Tc Length
460
Tc Length
380
To High Elev.
36,87
Tc High Elev.
36.87
Tc Low Elev.
33.76
Tc Low Elev.
35.03
Slope
0.0068
Slope
0,0048
To
6,00
Tc
5.89
To Factor (2)
0.4
Tc Factor l2}
0.4
To wl Factor
2.3984
To wl Factor
2.3542
Intensity ' i' "I
8
Intensity ' i ' (3)
8
Qi = C/A
5,4316
cfs
Qi = C rA
5.3493
1 cfs
Q to CB-6 from m DA-9
Drainage Area =
101,435
SF
Q.to CB-7 from DA-10
Drainage Area =
36,584
SF
Drainage Area =
2.33
Acres
Drainage Area =
0.84
Acres
Design Storm =
25
-YR storm
Design Storm =
25
-YR storm
rr
Surface
Acres
C- Value f�1
Surface
Acres C-Valuef'1
AsphaltlRooftop
Grass
0,6234
0,95
0.2
4 v
Asphalt/Rooftop
Grass
0.371
0.95
1.71
0,47
0.2
(� �cY
Total A'
2.3286
1!Q
Total 'A'
0.8398
1'
Weighted 'C'
0.400168
1
Weighted 'C'
0.531277
Tc Length
383.63
Tc Length
344.44
Tc High Elev.
36,87
Tc High Elev.
36,92
Tc Low Elev,
35.03
Tc Low Elev.
34,21
Slope
0.0048
Slope
0.0079
Tc
5.95
Tc
4.53
Tc Factor {2)
0.4
To Factor (2)
0.4
Tc wl Factor
2.3802
To wl Factor
1,8106
Intensity ' i ' @1
8
Intensity ' i ' (31
8
Qi = C rA
7.4659
cfs
Qi = C rA
3.5695
cfs
,Q to CB-8 from DA-11
Drainage Area =
29,855
SF
Q to CB-9 from DA-12
Drainage Area =
43,194 SF
Drainage Area =
0.69
Acres
Drainage Area =
0.99 Acres
Design Storm =
25
-YR storm
��
Design Storm =
25 -YR storm
Surface
Acres
C-Valuel'1
�1
Surface
Acres C- Value f'1
Asphalt)Rooftop
0.443
0.95
Asphalt/Rooftop
0.4736
0.95
rt
Grass
0.24
0.2
/"�/
Grass
0.52
0,2
t/
Total A'
0.6854
`/
Total A
0.9916
Weighted 'C'
0.6847861
Weighted 'C'
0,558213
To Length
344.44
Tc Length
443,33
Tc High Elev.
36.92
Tc High Elev.
36.5
Tc Low Elev.
34.21
-
Tc Low Elev.
34.19
Slope
0.0079
Slope
0.0052
To
4.53
Tc
6.44
Tc Factor (2)
0.4
Tc Factor (2)
0.4
Tc wl Factor
1,8106
Tc wl Factor
-2.5771
Intensity's' (3)
8
Intensity'i' (31
8
Qi = C rA
3.7547
cfs
Qi = C rA
4.4282
cfs
(1) Table 8.03a; {2) Figure 8.03a; (3) Figure 8.03b of the NCDENR Erosion and Sediment Control Planning and Design Manual. Revision Date: 9116/02

Farmstead Section 1
East Coast Engineering Company, PA
Catch Basin Curb Cut
DAH
Calculations
Q to CB-10 from DA-13
Drainage Area =
40,118
SF
Q to CC-4 from DA-14 Drainage Area =
50,202 SF
Drainage Area =
0.92
Acres
Drainage Area =
1.15
1
Acres
Design Storm =
25
-YR storm
Design Storm =
25
-YR storm
Surface
Acres
C-Value rr1
Surface
Acres C-Value r1)
Asphalt/Rooftop
0.4609
0.95
Asphalt/Rooftop
0.6877
0.95
Grass
0.46
0.2
Grass
0.46
0.2
J
Total A'
0.921
Total 'A'
1.1525
n
Weighted 'C'
0.575314
Weighted 'C'
0.647561
vfln
Tc Length
443.33
Tc Length
278.05
`
Tc High Elev.
36.5
Tc High Elev.
37.38
Tc Low Elev.
34.19
Tc Low Elev.
35.88
Slope
0.0052
Slope
0.0054
Tc
6.44
Tc
4.44
Tc Factor (2)
0.4
Tc Factor (2t
0.4
Tc wf Factor
2.5771
To wl Factor
1.7755
Intensity'i' (3)
8
Intensity'i' t3)
8
Qi = CM
4.2388
cfs
Qi = C rA
5.9704
cfs
(1) Table 8.033; (2) Figure 8.03a; (3) Figure 8.03b of the NCDENR Erosion and Sediment Control Planning and Design Manual. Revision gate: 9116/02

Farmstead Section 1
Wet Detention Basin Calculations
Pond 1
East Coast Engineering Company, PA
DAH
Drainage Area (DA) =
171,721 sf
or 3.94 ac
!m ervious Area (IA)=
95531 sf
2.19 ac
Percent Impervious (1)
IAIDA
0.56
or 56%
SAIDA; 90% TSS
(no vegetative filter req'd)
Pond Depth = 6.0
0.0312
or 3.12%
Min. re 'd SA @ PP
(SAIDA)x(DA)
5,357.70 sf
Min. req'd storage volume
Rv = 0.05 + (0.009 x I) = 0.551
Volume = 1 in x 1 ft 112 in x Rv x DA
7,880.33 cf
SA provided 2 PP
Oval Pond Elev = 30
5,622 sf
Enough SAprovided?
YES
Min. storage depth req'd
Min. storage volume / SA rovided PP
1.40 ft
Storage depth set at
1 A ft
Elevation of temporaty pool
31.4 ft
SA @ TemporaryPoo/
7,047 sf
Storage volume provided
Average of SA @ temp. pool & PP x storage depth
8,867.91 cf
Outlet Siziri
Q - 2 day drawdown time
Min. req'd storage volume x (1 in. 12 days)
0.046 cfs
Q - 5 daZ drawdown time
Min. req'd storage volume x 1 in. 15 days)
0.018 cfs
Height
h (1f2 Min. Storage Depth)
0.70 ft
C ,
Constant
0.6
Required Area for 0-2
A = Qf(C x (2gh)11)
1.63 in
Required Area for Q-5
A = Qf(C x (2gh)17 )
0.65 in
Orifice Choosen
1.25 in
CHECK
Area Provided by Orifice Choosen
A = n
1.23 in
Area Provided by Orifice Choosen
0.009 ft
The Average head
h = 1/2(Temporary Pool depth - 112(orifice diameter))
8.0875 in
The Average head
0.674 ft
Q provided
Q = Ca(2gh) 112
0.034 cfs OK
Emergency Spillway
25 YEAR DISCHARGE:
23.73 CFS
FREEBOARD HEIGHT:
1.15 FT
FREEBOARD ELEVATION:
32.55 FT
RISER:
30 IN
OUTLET PIPE:
24 IN
(Figure 8, 07b of NCDENR Erosion and Sediment Control Planning and Design Manual)
Revision Date: 9I16/02

Farmstead Section 1
Wet Detention Basin Calculations
Pond 2
East Coast Engineering Company, PA
DAH
Drainage Area (DA) =
303,324 sf
or 6.96 ac
Im ervious Area (!A)=
128248 sf
2.94 ac
Percent Impervious (I)
IAIDA
0.42
or 42%
SAIDA; 90% TSS
no vegetative filter re 'd
Pond Depth = 6.0
0.0222
or 2.22%
Min. re 'd SA @ PP
(SA/DA)x(DA)
6,733.80 sf
Min. req'd storage volume
Rv = 0.05 + (0.009 x 1) = 0.431
Volume = 1 in x(1 ft 1 12 in) x Rv x DA
10.882.45 cf
SA provided PP
Oval Pond Elev = 31
6,964 sf
Enough SAprovided?
YES
Min, storage depth re 'd
Min. storage volume 1 SA provided @ PP
1.56 ft
Storage depth set at
1.5 ft
Elevation of temporary pool
32.5 ft
SA @ TemporaT pool
8,634 sf
Storage volume rovided
Average of SA @ temp. pool & PP x storage depth
11,698.10 cf
OK
Outlet Sizing
Q - 2 day drawdown time
Min. req'd stora e volume x (1 in. 12 days)
0.063 cfs
Q - 5 day drawdown time
Min. re 'd storage volume x 1 in. 1 5 days)
0.025 cfs
Height
h 112 Min. Storage Depth)
0.75 ft
Co
Constant
0.6
Required Area for Q-2
A = QI(C x (2gh)12)
2.17 in
Required Area for 0-5
A = QI(C x (2gh)1!)
0.87 in
Orifice Choosen
1.50 in
CHECK
Area Provided by Orifice Choosen
A = nr
1.77 in
Area Provided by Orifice Choosen
0.012 ft'
The Average head
h = 1/2(Temporary Pool depth - 112(orifice diameter))
8.625 in
The Average head
0.719 ft
Q provided
❑ = Ca(2gh) r
0.050 cfs OK
Emergency Spillway
25 YEAR DISCHARGE:
28.81 CFS
FREEBOARD HEIGHT:
1.33 FT
FREEBOARD ELEVATION:
33.83 FT
RISER:
30 IN
OUTLET PIPE:
24 IN
(Figure 8.07b of NCDENR Erosion and Sediment Control Planning and Design Manual)
Revision Date: 9116/02

Farmstead Section 1
POND VS. FOREBAY
POND 1 VOLUME TO FOREBAY COMPARIS0�1
FOREBAY
2:1 SLOPE
BOTTOM SF
1 361.06
SURFACE SF
940.14
DEPTH
3
VOLUME
1952
East Coast Engineering Co., PA
DAFT
POND 2 VOLUME TO FOREBAY COMPARISON
FOREBAY
2:1 SLOPE
BOTTOM SF
1 529,08
SURFACE SF
L1231,75
DEPTH
3
VOLUME
2641
POND
POND
DEPTH
©
DEPTH
61
3:1 SLOPE
3:1 SLOPE
BOTTOM SF
1 88.191
BOTTOM SF
881
TOP SF
1914.43
TOP SF
2729.31
DEPTH
4.33
DEPTH
4.33
VOLUME
4336
VOLUME
6517
6:1 SLOPE
6:1 SLOPE
BOTTOM SF
1914.43
BOTTOM SF
2729.31
SURFACE SF
4568
SURFACE SF
5581.75
DEPTH
1.67
DEPTH
1.67
VOLUME
5413
VOLUME
6940
TOTAL POND VOLUME
9749
TOTAL POND VOLUME
13457
FOREBAY % OF POND
20%
FOREBAY % OF POND
20%

Farmstead Section 1
Pipe Sizing, Inverts
East Coast Engineering Company, PA
DAH
Catch Basin I
Contributing DAs
I Total Q
I Pipe Size
I Slope
I Q MAX
Top
CB-1
1
4.74
15
0.005
4.95
34.80
CB-2
1,2
8.52
18
0,006
8.81
34.80
CB-3
3
5.69
15
0.023
10.56
34.00
CB-4
1,2,3,4
23.73
24
0.010
24.50
34.00
Pipe
From
To
Pipe Size
Inv In
I Slope
Pipe Length
Inv Out
SD-1
CB-1
CB-2
15
31.8
0.005
45
31.58
SD-2
CB-2
JB-1
18
31,48
0.006
211
30.21
SD-3
JB-1
CB-4
18
30.11
0.006
213
28.83
SD-4
CB-3
CB-4
15
31
0.023
95
28.83
SD-5
CB-4
JB-2
24
28.73
0.003
207
28.13
SD-6
JB-2
POND
24
28.03
0.003
1 219
1 27.39
Catch Basin
Contributing DAs
Total Q
Pipe Size
Slope
Q MAX
Top
CB-5
8
5.35
15
0.0060
5.42
35.26
CB-6 ._
8,9
12.82
24
0.0076
21.32
35.26
CB-7
10
3.57
12
0.0100
3.86
34.39
CB-8
10,11
7.32
18
0.0050
8.04
34.39
CB-9
8,9,12
17.24
24
0.0050
17.32
34.37
CB-10
8,9,10,11,12,13
28.81
24
0.0140
28.98
34.37
Pie
From
To
Pipe Size
Inv In
Slope
Pipe Length
Inv Out
SD-7
CB-5
CB-6
15
32.26
0.0060
25
32.11
SD-8
CB-6
CB-9
24
32.01
0.0076
256
30.07
SD-9
CB-9
CB-10
24
29.97
0.0050
21
29.87
SD-10
CB-7
CB-8
12
31.39
0,0100
21
31.18
SD-11
CB-8
CB-10
18
31.08
0.0050
242
29.87
SD-12
CB-10
JB-3
24
29.77
0.0042
274
28.62
SD-13
JB-3
POND
36
28.52
0.0042
93
28.13
Revision Date: 9116/02

Farmstead Section 1
Catch Basin Calculations
Neenah Foundry Curb Inlet
Perimeter Provided (ft)
Open Area Provided (ft)
R-3501-R
5.50
2.64
Catch Basin ID
Q (cfs)
Min.
Permimeter
Required (ft)
Min. Open
Area Required
(ft)
CB-1
4.74
7.63
1.66
CB-2
3.78
6.09
1.33
CB-3
5.69
9.16
2.00
CB-4
4.78
7.69
1.68
CB-5
5.35
8.61
1.88
C13-6
7.47
12.02
2.62
CB-7
3.57
5.75
1.25
CB-8
3.75
6.05
1.32
CB-9 _
4.43
7.13
1.55
CB-10
4.24
6.82
1.49
Minimum Permeter = Q /(CH12) where C = 3.0, H = 0.35
Minimum Open Area = Q 1 C x (2gH)1/2 where C = 0.6, H = 0.36, G = 32.2
East Coast Engineering Company, PA
DAH
Revision Date: 9/26102

NARRATIVE RECEIVED
for
Farmstead Section 1 OCT 2 2 2002
Brunswick County, NC DWQ
DESCRIPTION PROM # C�%�' p2 /0 z
The project area is a 38.96-acre tract of the total 470-acre Farmstead Golf Course
development located in Brunswick County, NC, near Calabash. It is located off McLamb
Road (SR 1301) adjacent to the head of Hickmans Branch (C:Sw waters). The proposed
development on the site is a residential development consisting of sixty (60) home sites.
The site is cleared with sandy topsoil and grades ranging from 0.5% to 2.0%. The site
will be graded to accommodate the purposed plans. Construction is scheduled to begin as
soon as all permits and approvals are obtained.
STORMWATER MEASURES
The stormwater will be treated with a mixture of high -density and low -density
stormwater features, but as such, will be classified as a high -density project. The total
proposed impervious percentage is 29.98%. The stormwater runoff from the site is
estimated using the rational method for a 25-year event using published historical rainfall
data for the area. The proposed grading for the lots is such that only a portion will drain
toward the roadway curb and gutter. The stormwater run-off from the lots will be
directed to the roadway curb and gutter by overland flow. The stormwater will collect
into ten (10) catch basins and four (4) curb cuts located along the curbed roadway. The
catch basins will route the stormwater to two (2) independent wet detention basins
through two (2) independent series of storm drainage pipes, and the curb cuts will direct
the stormwater to four (4) independent vegetated swales. The rear of the lots will drain
by overland flow with the existing topography of the site away from the roadways.
EROSION CONTROL MEASURES
The perimeter of the project boundary will be protected from erosion with silt
fencing. Vegetation will be established quickly in the swales and around the wet
detention basins. Excelsior erosion protection will be used temporarily in the swales to
eliminate soil crosion and check dams will be located at the end of the swales. Gravel
inlet protection will be used around the catch basins until the roadway curb and gutter is
installed and the roadway is paved. The grading contractor and the developer will
provide the maintenance for the erosion control measures.
CONSTRUCTION SEQUENCE
The Contractor will install silt fence prior to beginning any clearing and. grading
operations. The wet detention basins will be constructed and runoff will be directed to
the basins during grading operation of the lots and the swales. The roadway will be
rough graded. The swales will be established and protected with excelsior and check
dams. The water and sewer utilities will be installed. The storm drainage features will be
installed and inlet protection will be established. The curb and gutter and the roadway
will be installed. The disturbed areas will be landscaped and seeded upon completion,
and as soon as possible. The wet detention basins will be restored to design
specifications after completion of all other construction.

PROPOSED
DEED RESTRICTIONS
AND PROTECTIVE COVENTANTS
For
FARMSTEAD SECTION 1
LOTS 1-60
L The following covenants are intended to ensure ongoing compliance with State
Stormwater Management Permit Number SW8 as issued by the Division of Water
Quality under NCAC 214.1000.
2. The State of North Carolina is made a beneficiary of these covenants to the extent
necessary to maintain compliance with the stormwater management permit.
3. These covenants are to run with the land and be binding on all persons and parties
-claiming under them.
4. The covenants pertaining to stormwater may not be altered or rescinded without the
express written consent of the State of North Carolina, Division of Water Quality.
5. Alteration of the drainage as shown on the approved plan may not take place without the
concurrence of the Division of Water Quality.
6. The maximum allowable built -upon area per lot is 6500 square feet for Lots 1 — 60. This
allotted amount includes any built -upon area constructed within the lot property
boundaries, and that portion of the right-of-way between the front lot line and the edge of
the pavement. Built upon area includes, but is not limited to, structures, asphalt,
concrete, gravel, brick, stone, slate, and coquina, built does not include raised, open wood
decking, or the water surface of swimming pools.
7. Filling in or piping of any vegetative conveyances (ditches, swales, etc.) associated with
the development except for average driveway crossing, is strictly prohibited by any
persons.
8. Each lot will maintain a 30' wide vegetated buffer between all impervious areas and
surface waters.
9. All roof drains shall terminate at least 30' from the mean high water mark of surface
waters.
10. "Lots within CAMA's Area of Environmental Concern may have the permitted
maximum built -upon area reduced due to CAMA jurisdiction with the AEC."

DRAINAGE AREA TABLE
for
Farmstead Golf Course
Brunswick County, NC
Bassin Information
Drainage Area
Drainage Area
Overall Site -
Brunswick County,
NC
Section 1 - Total
Project Area
Receiving Stream Name i
Hickmans Branch
Hickmans Branch
Receiving Stream Class
C: Sw
C: Sw
Drainage Area
13,601,520
SF
1,738,336
SF
Existing Impervious Area
116,211
SF
15,685
SF
,Proposed Impervious Area
521,165
SF
505,480
SF
Impervious Area
1 4.69%
1 29.98%
Impervious Surface Area
Drainage Area 1
Drainage Area 2
On -Site Buildings
402,350
SF
390,350
SF
On -Site Streets
159,324
SF
127,818
SF
On -Site Parking
50,104
SF
0
SF
On -Site Sidewalks
2,448
SF
0
SF
Other On -Site (Cartpaths)
325,074
JSFJ
2,997
SF
Off -Site
0
SF
0
SF
Total: 1 561,674 JSFJ 521,165 SF
Basin Information
Drainage Area
Drainage Area
Drainage Area
within Section 1 to
Pond #1
Drainage Area
within Section 1 to
Pond #2
Receivinq Stream Name
Hickmans Branch
Hickmans Branch
Receiving Stream Class
C: Sw
C: Sw
Drainage Area
171721
SF
303325
SF
Existing Impervious Area
0
SF
0
SF
.Proposed Impervious Area
95531
SF
128248
SF
Impervious Area
56%
42%
Impervious Surface Area
Drainage Area 3
Drainage Area 4
On -Site Buildings
36668
SF
66000
SF
On -Site Streets
38863
SF
37248
SF
On -Site Parking
0
SF
0
SF
On -Site Sidewalks
0
SF
0
SF
Other On -Site (Driveway52
20000
SFJ
25000
SF
Off -Site
0
JSFJ
0
SF
Total: 95531 1 SF 128248 1 SF

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