Plato Lee Retail Substation - Att_1_Stormwater_Calculations

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Plato Lee - East Channel Depth and Veloc
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.035
Channel Slope 0,01800 ft/ft
Left Side Slope 4.00 ft/ft (H:V)
Right Side Slope 4.00 ft/ft (H:V)
Bottom Width 2.00 ft
Discharge 3.37 ft3/s
Results
Normal Depth 4.75 in
Flow Area 1.42 ftz
Wetted Perimeter 5.27 ft
Hydraulic Radius 3.23 in
Top Width 5.17 ft
Critical Depth 0.35 ft
Critical Slope 0.02909 ft/ft
Velocity 2.37 ft/s
Velocity Head 0.09 ft
Specific Energy 0.48 ft
Froude Number 0.80
Flow Type Subcritical
GVF Input Data
Downstream Depth 0.00 in
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 in
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 4.75 in
Critical Depth 0.35 ft
Channel Slope 0,01800 ft/ft
Bentley
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Plato Lee - East Channel Depth and Velocity
GVF Output Data
Critical Slope
0.02909 ft/ft
Bentley Systems, Inc. Haestad Methods Soli5iea�fl�fitewMaster VSi (SELECTseries 1) [08.11.01.03]
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User Input Data
Calculated Value
Reference Data
Designed By: sDA Date: 5i2si2o�s
Checked By: SPD Date: 5/23/2018
Company: BMCD
Project Name: PLATO LEE
Project No.: 105658
Site Location (City/Town) SHELBY
ChannelMlaterway Id. 1 (EAST)
Step 1. Detenuiue the requued fio�s• capacit}�. Q, by estuuatiue pz•jk nuioff
rate for the design storm (dppenrlit- 5.0 ).
Design storm
Required NOW, U (cfs)
10-yr
3.37
Step 2. Determine the slope att<l select cltatvtet geotnetty and litung.
Slope (ft/ft) 0.018
Channel geometry: V, Parabolic, or
Trapezoidal Trapezoidal
Channel lining Tall Fescue
Step 3. Detenuute the pei•�tussible �•elocity for [Ite liuiae selected, or the
desired t elocit<, if pay ed. (see Table S.OSa, page S.OS.�)
Permissible velocity (ft/s)
4.5 Table 8.05a
Step 4. Make mt i�utial estimate of chaiutel size—cii�•ide the required Q by the
pemussible �•elocity to reach a �`fust t���' estimate of cha�uiel fto�e m�ea. Theo
select a geometiN, depth.. uid top width to fit site conditious.
Channel flow area (ft) "first try" 0.75
Y
a3 y' U
o ° a N o a > a ° m m M c'� a
m Eo ❑ `� y Q m E m> > v a N G v
a) x n o ° `oa 6 M; �N ca) o o mn. m0.
v O m O a> >. m m a� [Y a) as o d a) as .c m
Trapezoidal --Grass Lined co m � U M � LL = W F> >�> of U > > U U U U
Figure 8.05b (ft/ft) (ft) (ft) (ft) (ft2) (ft) (ft) (ft/s) (fus) (cfs)
D Lo
O O O O O O O O OLn
Ln
O O
co 00
m co co co w a) _ co m ro
LL LL LL LL LL LL LL LL > H > LL ll. LL
❑ ❑
W W
W W
U U
O O
Graded Channel, East of Substation Pad 4 2.0 0.4 5.2 1.44 5.30 0,27 2.4 0.65 B 0.035 2.4 a 3 a

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Plato Lee - West Channel Depth and Velocity
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient
0.035
Channel Slope
0.03200
ft/ft
Left Side Slope
4.00
ft/ft(H:V)
Right Side Slope
4.00
ft/ft (H:V)
Bottom Width
2.00
ft
Discharge
4.95
ft3/s
Results
Normal Depth
4.99
in
Flow Area
1.52
ft2
Wetted Perimeter
5.43
ft
Hydraulic Radius
3.36
in
Top Width
5.32
ft
Critical Depth
0.43
ft
Critical Slope
0,02752
ft/ft
Velocity
3.25
ft/s
Velocity Head
0.16
ft
Specific Energy
0.58
ft
Froude Number
1.07
Flow Type
Supercritical
GVF Input Data
Downstream Depth 0.00 in
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 in
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 4.99 in
Critical Depth 0.43 ft
Channel Slope 0,03200 ft/ft
Bentley
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Plato Lee - West Channel Depth and Velocity
GVF Output Data
Critical Slope
0.02752 ft/ft
Bentley
Systems, Inc. Haestad Methods Sol@emAl�FtewMaster V8i (SELECTseries 1) [08.11.01.03]
5123I2018 9:54:06 AM 27 Siemons Company
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of
2

user input Data
Calculated Value
Reference Data
Designed By: sDA Date: 5i23i2018
Checked By: SPD Date: 5/23/2018
Company: BMCD
Project Name: PLATO LEE
Project No.: 105658
Site Location (City/Town) SHELBY
Channel/Waterway Id. 2 (WEST)
Step 1. Determine the requued How capacity. Q, Uy estiumtiue pznl: nmoff
rate for the design stoiYn (dppMdix S.03).
Design storm
Required Flow, Q (cfs)
10-yr
4.95
Step 2. Determine the slope and select chatuiel geometiS� and titan°.
Slope (ft/ft) 0.032
Channel geometry: V, Parabolic, or
Trapezoidal Trapezoidal
Channel lining Tall Fescue
Step 3. Detentutte the peruissiUle velocity for the lining selected, or the
desired velocity, if paved. (see Table S.OSn, page 3.05.�)
Permissible velocity (ft/s)
4.5 Table 8.05a
Step 4. Make au ittitiml estimate of chmiutel size —divide the requu-ed Q Uy the
perttissiUle velocity to reach a -first h}''estimate of cha�mel flow u�ea. Then
select a geometry. depth. mud top width to fit site conditions.
Channel flow area (ftz) "first try" 1.10
C
v o w a) c> K o C C N c > U O U
o p a NQ as > u :°v �a �� �' C c
ro X o C ° E m`o � m m C d o o �a n °
Trapezoidal --Grass Lined n Co 9 � 0 >> L `° °' ° > ° -° ° ° °' 0 @ 0 `°
Figure 8.05b (fuft) (ft) (ft) (ft) (ft) (ft) (ft) (ft/s) (fus) (cfs)
9
� to N N
O O O O O I
OOOO L LL LL LL LL > > LL IL LL
� � O
W W
W W
U U
O O
Graded Channel, East of Substation Pad 4 2.0 0.4 5.2 1.44 5.30 0.27 3.7 1.01 B 0,03 3.7 W 5 a

G DrRPAP TIMUfV NILDIMU, LFILL LM V I©N�) PUR "WJ1 I VMLL LJ�ZP

Hydrograph Report WTFAU- lb-G�
2
Hydraflow Hydrographs Extension for AutoCADO Civil 3D0 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
Storm frequency
Time interval
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
Q (cfs)
14.00
12.00
10.00
8.00
6.00
4.00
2.00
0.00
= SCS Runoff
= 25 yrs
= 2 min
= 1.630 ac
= 0.0 %
= User
= 6.46 in
= 24 h rs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
SPCC
Hyd, No. 1 -- 25 Year
0 120 240 360 480 600 720 840 960
Hyd No. 1
Wednesday, 05 / 23 / 2018
= 12.45 cfs
= 716 min
= 26,282 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
1080
Q (cfs)
14.00
12.00
10.00
8.00
6.00
4.00
2.00
1200
Time (min)

Outfall D=5
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.013
Channel Slope 0.01820 ft/ft
Diameter 18.00 in
Discharge 12.45 ft'/s
Results
Normal Depth 13.09 in
Flow Area 1.38 ft2
Wetted Perimeter 3.06 ft
Hydraulic Radius 5.39 in
Top Width 1.34 ft
Critical Depth 1.33 ft
Percent Full 72.7 %
Critical Slope 0,01252 ft/ft
Velocity 9.05 ft/s
Velocity Head 1.27 ft
Specific Energy 2.36 ft
Froude Number 1.57
Maximum Discharge 15.24 ft'/s
Discharge Full 14.17 W/s
Slope Full 0,01405 ft/ft
Flow Type SuperCritical
GVF Input Data
Downstream Depth 0.00 in
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 in
Profile Description
Profile Headloss 0.00 ft
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 72•71 %
Downstream Velocity Infinity ft/s
Bentley
Systems, Inc. Haestad Methods SoliS®rtl6fi51eiavMaster V8i (SELECTseries 1) [08.11.01.03]
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Outfall D=5
GVF Output Data
Upstream Velocity Infinity ft/s
Normal Depth 13.09 in
Critical Depth 1.33 ft
Channel Slope 0.01820 ft/ft
Critical Slope 0.01252 ft/ft
Bentley
Systems, Inc. Haestad Methods Soli6®rtl�fiteiovMaster V8i (SELECTseries 1) [08.11.01.03]
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f
�uTFAzL� ` >-5s
�c 'Fo2 PIPE f!j `t AQ-71A L
a p �ee-c.J , un
v +1 , A/s
(� m q�s
3 5 10 20 50 100 200 500
Discharge (ft3/sec)
Appendices
loon
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (T�,, < 0.5 diameter).
use 13 ;.\
d= , oS� -� UsE 9 tps
Use, 13
6�5-Di
Rev. l2/93
8.06.3

RIPRAP APR®IV SIZING CALCULATI®RI� VLYhA VU 0 r LL L�/.

Hydrograph Report OUTFItt'G E —z
2
Hydraflow Hydrographs Extension for AutoCADO Civil 3DO 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type = SCS Runoff Peak discharge
Storm frequency = 25 yrs Time to peak
Time interval = 2 min Hyd. volume
Drainage area = 1.190 ac Curve number
Basin Slope = 0.0 % Hydraulic length
Tc method = User Time of conc. (Tc)
Total precip. = 6.46 in Distribution
Storm duration = 24 hrs Shape factor
5.00
4.00
3.00
2.00
1
Wednesday, 05 / 23 / 2018
= 5.068 cfs
= 718 min
= 101139 cuft
= 63
= 0 ft
= 5.00 min
= Type II
= 484
120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 1
5.00
4.00
3.00
2.00
1560
Time (min)

OUlTall E-2
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.013
Channel Slope 0,01000 ft/ft
Diameter 15.00 in
Discharge 5.07 ft3/s
Results
Normal Depth
10.00
in
Flow Area
0.87
ftz
Wetted Perimeter
2.39
ft
Hydraulic Radius
4.37
in
Top Width
1.18
ft
Critical Depth
0.91
ft
Percent Full
66.7
%
Critical Slope
0,00789
ft/ft
Velocity
5.83
ft/s
Velocity Head
0.53
ft
Specific Energy
1.36
ft
Froude Number
1.20
Maximum Discharge
6.95
ft3/s
Discharge Full
6.46
ft3/s
Slope Full
0,00616
ft/ft
Flow Type
SuperCritical
GVF Input Data
Downstream Depth 0.00 in
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 in
Profile Description
Profile Headloss 0.00 ft
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 66.69 %
Downstream Velocity Infinity ft/s
Bentley
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OWall E=2
GVF Output Data
Upstream Velocity
Infinity
ft/s
Normal Depth
10.00
in
Critical Depth
0.91
ft
Channel Slope
0.01000
ft/ft
Critical Slope
0,00789
ft/ft
Bentley
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CCU TPA LL E`Z
t SEE� MOTE$ ON OOTF I-! 1:- S WMrt SHEGT
3 5 10 20 50 100 200 500
Discharge (ft3/sec)
Appendices
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from around pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
OV TFArLL E - 2_
(;� ( 0 • a-U n USE ►2 i n t21 P2RP USA
Rev. 12/93 8.06.3

I V6A V IAVRUIV M40IM" LIALLUIL 0 HUIW5 MR UM U IMLL [��Z

Hydrograph Report
�U TF=Ar LL F � nz�
z
Hydraflow Hydrographs Extension for AutoCADO Civil 3D0 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
Storm frequency
Time interval
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
Q (cfs)
5.00
4.00
3.00
2.00
0.00
= SCS Runoff
= 25 yrs
= 2 min
= 0.530 ac
= 0.0 %
= User
= 6.46 in
= 24 h rs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
SPCC
Hyd. No. 1 -- 25 Year
Wednesday, 05 / 23 / 2018
= 4.047 cfs
= 716 min
= 8,546 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
0 120 240 360 480 600 720 840 960
Hyd No. 1
1080
1200
Q (cfs)
5.00
4.00
3.00
2.00
1.00
Time (min)

Outfall F=2
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.013
Channel Slope 0.01000 ft/ft
Diameter 15.00 in
Discharge 4.05 ft3/s
Results
Normal Depth
8.61
in
Flow Area
0.73
ft2
Wetted Perimeter
2.15
ft
Hydraulic Radius
4.07
in
Top Width
1.24
ft
Critical Depth
0.81
ft
Percent Full
57.4
%
Critical Slope
0.00682
ft/ft
Velocity
5.56
ft/s
Velocity Head
0.48
ft
Specific Energy
1.20
ft
Froude Number
1.28
Maximum Discharge
6.95
ft/s
Discharge Full
6.46
ft/s
Slope Full
0.00393
ft/ft
Flow Type
SuperCritical
GVF Input Data
Downstream Depth 0.00 in
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 in
Profile Description
Profile Headloss 0.00 ft
Average End Depth Over Rise 0.00 %
Normal Depth Over Rise 57.37 %
Downstream Velocity Infinity ft/s
Bentley
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of 2

OWall F-2
GVF Output Data
Upstream Velocity Infinity ft/s
Normal Depth 8.61 in
Critical Depth 0.81 ft
Channel Slope 0,01000 ft/ft
Critical Slope 0,00682 fUft
Bentley
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2

Appendices
r StVS7 No7;E5 oN o%J-r"tf\. D-Sm WoRt�SK�ET
3 5 10 20 50 100 200 500
Discharge (ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
ovTFAI�L
10s� g,
c
Rev. ]2/93 8.06.3

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Plato Lee Retail Substation
Area Drain Sizing Calculations
Orifice Equation: Q = C*A*SQRT(2*32.2*h)
Area drain inflows are per the attached 25 yr/24-hr storm event hydrographs.
Pre-cast5quare Area Drains
Inlet
No.
Area (AC)
Inflow Q
(cfs)
Inlet ID
Inlet Area
(SF)
Drain Clog
Head (ft)
Inlet
Coefficient
Drain Q
(cfs)
Total Drain Q
(cfs)
Drain Q > Inflow
Q
Notes
A-1
0.28
2.14
24NMI'
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
A-2
0.22
1.68
2411x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
B-1
0.19
1.45
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
B-2
0.18
1.37
24"x24"
1.86
25%
0.16
0.7
1 3.13
1 3.33
YES
(1)
C-1
0.36
2.75
241N24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
C-2
0.40
3.05
2411x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
E-1
1.17
7.93
24"x24"
1.86
25%
1.08
0.7
8.14
8.14
YES
(2)
(1)
Includes total drain
capacity with (8)
2" Weep Holes, 6" Below
Grade, per the below table.
(2)
Area Drain is placed
with 1.59 feet of
freeboard to the nearest
edge of pavement, maintaining 0.5 feet of freeboard during storm event.
Area Drain Weep Holes
Inlet Area
Inlet
Drain Q
Total Drain Q
Drain Q > Inflow
Weep Holes
nlet ID
Drain Clog
Head (ft)
Notes
I
(SF)
Coefficient
(cfs)
(cfs)
I Q
Typical
1 2" Dia.
0.005454
0%
0.66
1 0.7
0.025
0.20
1 YES
(3)
(3) Each weep hole will be covered with filter fabric and drain from the yard stone area to minimize clogging. Head includes 6" depth of yard stone plus 2"
head above rim of inlet.

Hydrograph Report INLET" A-
2
Hyd raflow Hydrographs Extension for AutoCADO Civil 3DO 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type = SCS Runoff Peak discharge = 2.138 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 4,515 cuft
Drainage area = 0.280 ac Curve number = 85
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.46 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
SPCC
Q (cfs) Hyd. No. 1 -- 25 Year
3.00
2.00
0.00
0 120 240 360 480 600 720 840 960
Hyd No. 1
1080
Q (cfs)
3.00
2.00
1200
Time (min)

Hydrograph Report INL-ST A�Z
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D®2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
Storm frequency
Time interval
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
Q (cfs)
2.00
0.00
= SCS Runoff
= 25 yrs
= 2 min
= 0.220 ac
= 0.0 %
= User
= 6.46 in
= 24 h rs
Peak discharge = 1.680 cfs
Time to peak = 716 min
Hyd. volume = 3,547 cuft
Curve number = 85
Hydraulic length = 0 ft
Time of conc. (Tc) = 5.00 min
Distribution = Type II
Shape factor = 484
SPCC
Hyd. No. 1 -- 25 Year
0 120 240 360 480 600 720 840 960
H
yd No. 1
Q (cfs)
2.00
1200
Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCADO Civil 3DO 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type = SCS Runoff Peak discharge = 1.451 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 3,064 cuft
Drainage area = 0.190 ac Curve number = 85
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.46 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Q (cfs)
2.00
SPCC
Hyd. No. 1 -- 25 YearW L
120 240 360 480 600 720 840 960 1080
Hyd
No. 1
Q (cfs)
2.00
1.00
1200
Time (min)

2
Hydrograph Report �N g
Hydraflow Hydrographs Extension for AutoCADO Civil 3DO 2016 by Autodesk, Inc. 00.5
Hyd. No. 1
SPCC
Hydrograph type = SCS Runoff Peak discharge = 1.374 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 2,902 cuft
Drainage area = 0.180 ac Curve number = 85
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.46 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Q (cfs)
2.00
0.00
SPCC
Hyd. No. 1 -- 25 Year
0 120 240 360 480 600 720 840 960
Hyd No. 1
1080
Q (cfs)
2.00
1200
Time (min)

Hydrograph Report
y N LJE 1r C- 1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
Storm frequency
Time interval
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
Q (cfs)
3.00
2.00
0.00
i
= SCS Runoff
= 25 yrs
= 2 min
= 0.360 ac
= 0.0 %
= User
= 6.46 in
= 24 h rs
Peak discharge = 2.749 cfs
Time to peak = 716 min
Hyd. volume = 5,805 cuft
Curve number = 85
Hydraulic length = 0 ft
Time of conc. (Tc) = 5.00 min
Distribution = Type II
Shape factor = 484
SPCC
Hyd. No. 1 -- 25 Year
0 120 240 360 480 600 720 840 960
Hyd No. 1
1080
Q (cfs)
3.00
2.00
1200
Time (min)

Hydrograph Report
Ie�LEI (
E
Hydraflow Hydrographs Extension for AutocAD® civil 3D9 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type = SCS Runoff Peak discharge = 3.054 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 6,450 cuft
Drainage area = 0.400 ac Curve number = 85
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.46 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
SPCC
Q (cfs) Hyd. No. 1 -- 25 Year
4.00
3.00
2.00
0.00
0 120 240 360 480 600 720 840 960
Hyd No. 1
1080
Q (cfs)
4.00
3.00
2.00
1200
Time (min)

Hydrograph Report
INLET-�
Hydraflow Hydrographs Extension for AutoCADO Civil 31DO 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
Storm frequency
Time interval
Drainage area
Basin Slope
Tc method
Total precip.
Storm duration
Q (cfs)
8.00
6.00
4.00
2.00
0.00
Hyd No. 1
= SCS Runoff
= 25 yrs
= 2 min
= 1.170 ac
= 0.0 %
= User
= 6.46 in
= 24 hrs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 7.934 cfs
= 716 min
= 16,297 cuft
= 79
= 0 ft
= 5.00 min
= Type II
= 484
240 360 480 600 720 840 960 1080 1200
Q (cfs)
8.00
6.00
4.00
2.00
1320
Time (min)

Plato Lee Retail Substation
Area Drain Sizing Calculations
Orifice Equation: Q= C*A*SQRT(2*32.2*h)
Area drain inflows are per the attached 25-yr/24-hr storm event hydrographs.
Pre-castSquareArea Drains
Inlet
No
Area (AC)
Inflow Q
(cfs)
Inlet ID
Inlet Area
(SF)
Drain Clog
Head (ft)
Inlet
Coefficient
Drain Q
(cfs)
Total Drain Q
(cfs)
Drain Q > Inflow
Q
Notes
A-1
0.28
2.14
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
A-2
0.22
1.68
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
B-1
0.19
1.45
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
B-2
0.18
1.37
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
C-1
0.36
2.75
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
C-2
0.40
3.05
24"x24"
1.86
25%
0.16
0.7
3.13
3.33
YES
(1)
E-1
1.17
7.93
24"x24"
1.86
25%
1.08
0.7
8.14
8.14
YES
(2)
(1) Includes total drain capacity with (8) 2" Weep Holes, 6" Below Grade, per the below table.
(2) Area Drain is placed with 1.59 feet of freeboard to the nearest edge of pavement, maintaining 0.5 feet of freeboard during storm event.
Area Drain Weep Holes
Inlet Area
Inlet
Drain Q
Total Drain Q
Drain Q > Inflow
Weep Holes
Inlet ID
Drain Clog
Head (ft)
Notes
(SF)
Coefficient
(cfs)
(cfs)
Q
Typical
1 2" Dia.
I 0.005454
1 0%
0.66
0.7
0.025
1 0.20
YES
(3)
(3) Each weep hole will be covered with filter fabric and drain from the yard stone area to minimize clogging. Head includes 6" depth of yard stone plus 2"
head above rim of inlet.

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.280 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
0.00 ' 1'
0 120 240
Hyd No. 1
SPCC
Hyd. No. 1 -- 2 Year
Tuesday, 05 / 29 / 2018
= 1.025 cfs
= 716 min
= 2,088 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
360 480 600 720 840 960 1080 1200 1320
Q (cfs)
2.00
1.00
0.00
1440
Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.280 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
3.00
2.00
1.00
0.00 ' '
0 120
Hyd No. 1
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 2.138 cfs
= 716 min
= 4,515 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
240 360 480 600 720 840 960 1080
Q (cfs)
3.00
2.00
1.00
--1 0.00
1200
Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.220 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
Tuesday, 05 / 29 / 2018
= 0.805 cfs
= 716 min
= 1,641 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
1 1 �1 .1 �:/ .11 / :�1 •.1 1:1 11 1 ��1
Q (cfs)
1.00
0.90
0.80
0.70
1 .1
0.50
0.40
0.30
0.20

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.220 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
w1 11 '
1
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 1.680 cfs
= 716 min
= 3,547 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
120 240 360 480 600 720 840 960 1080
Hyd No. 1
Q (cfs)
2.00
1.00
— 0.00
1200
Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.190 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
SPCC
Hyd. No. 1 -- 2 Year
Tuesday, 05 / 29 / 2018
= 0.695 cfs
= 716 min
= 1,417 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
Q (cfs)
1.00
0.90
0.80
0.70
0.50
0.40
0.30
0.20
0.10
0 00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 1 Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.190 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
w1 11 '
1
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 1.451 cfs
= 716 min
= 3,064 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
120 240 360 480 600 720 840 960 1080
Hyd No. 1
Q (cfs)
2.00
1.00
--1 0.00
1200
Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.180 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
SPCC
Hyd. No. 1 -- 2 Year
Tuesday, 05 / 29 / 2018
= 0.659 cfs
= 716 min
= 1,342 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
Q (cfs)
1.00
0.90
0.80
0.70
0.50
0.40
0.30
0.20
0.10
0 00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 1 Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.180 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
w1 11 '
1
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 1.374 cfs
= 716 min
= 2,902 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
120 240 360 480 600 720 840 960 1080
Hyd No. 1
Q (cfs)
2.00
1.00
--* 0.00
1200
Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.360 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
0.00 ' 1'
0 120 240
Hyd No. 1
SPCC
Hyd. No. 1 -- 2 Year
Tuesday, 05 / 29 / 2018
= 1.317 cfs
= 716 min
= 2,685 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
360 480 600 720 840 960 1080 1200 1320
Q (cfs)
2.00
1.00
0.00
1440
Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.360 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
3.00
2.00
1.00
0.00 ' '
0 120
Hyd No. 1
SPCC
Hyd. No. 1 -- 25 Year
Tuesday, 05 / 29 / 2018
= 2.749 cfs
= 716 min
= 5,805 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
240 360 480 600 720 840 960 1080
Q (cfs)
3.00
2.00
1.00
— 0.00
1200
Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 0.400 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
2.00
1.00
0.00 ' 1'
0 120 240
Hyd No. 1
SPCC
Hyd. No. 1 -- 2 Year
Tuesday, 05 / 29 / 2018
= 1.464 cfs
= 716 min
= 2,983 cuft
= 85
= 0 ft
= 5.00 min
= Type II
= 484
360 480 600 720 840 960 1080 1200 1320
Q (cfs)
2.00
1.00
--* 0.00
1440
Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.E
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 0.400 ac
Basin Slope
= 0.0 %
Tc method
= User
Total precip.
= 6.46 in
Storm duration
= 24 hrs
SPCC
Tuesday, 05 / 29 / 2018
Peak discharge
= 3.054 cfs
Time to peak
= 716 min
Hyd. volume
= 6,450 cuft
Curve number
= 85
Hydraulic length
= 0 ft
Time of conc. (Tc)
= 5.00 min
Distribution
= Type II
Shape factor
= 484
Q (cfs) Hyd. No. 1 -- 25 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
LJ
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200
Hyd No. 1 Time (min)

Hydrograph Report
1
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.170 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 3.70 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
4.00
3.00
2.00
1.00
SPCC
Hyd. No. 1 -- 2 Year
0.00 ' 1 1'
0 120 240 360 480 600 720 840
— Hyd No. 1
Tuesday, 05 / 29 / 2018
= 3.402 cfs
= 718 min
= 6,860 cuft
= 79
= 0 ft
= 5.00 min
= Type II
= 484
Q (cfs)
4.00
3.00
2.00
1.00
1 0.00
960 1080 1200 1320 1440 1560
Time (min)

Hydrograph Report
2
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v10.5
Hyd. No. 1
SPCC
Hydrograph type
= SCS Runoff
Peak discharge
Storm frequency
= 25 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Drainage area
= 1.170 ac
Curve number
Basin Slope
= 0.0 %
Hydraulic length
Tc method
= User
Time of conc. (Tc)
Total precip.
= 6.46 in
Distribution
Storm duration
= 24 hrs
Shape factor
Q (cfs)
8.00
4.00
2.00
0.00
0 120 240
Hyd No. 1
SPCC
Hyd. No. 1 -- 25 Year
360 480 600 720 840 960
Tuesday, 05 / 29 / 2018
= 7.934 cfs
= 716 min
= 16,297 cuft
= 79
= 0 ft
= 5.00 min
= Type II
= 484
Q (cfs)
8.00
4.00
2.00
0.00
1080 1200 1320
Time (min)

�ulvilvil�Ry Ul= UK11MI-A"t KtAN
�VKK�/p©�) I ®UL LLUVOViLCOv d Uu)Lui K"E I [I=I I aui�� MU I RAL"Uuuilcu)

Pre -Development Drainage Area Calculations
Drainage Area =
Total Drainage Area:
Area Type
Open Space (Appling)
Open Space (Cecil)
Impervious Area, Existing pvmt
Offsite Existing Residential
Area Type
Open Space
11 •�.
Weighted C =
Impervious Area
Impervious Area
Residential District, 1-acre lots
Runoff
Storm 1 (2-yr/24-hr)
Storm 2 (2-yr/24-hr)
Storm 3 (25-yr/24-hr)
212,397 SF
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
= 4.88 AC
Area Area
SF Ac. CN
177,043 4.06 61
28,683 0.66 61
0 0.00 98
61671 0.15 68
61.22 Use 62
TR-55
CN Notes
61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
98 Asphalt or Concrete Pavement
85 Gravel
68 Cecil Sand clav loam (HSG B)
3.70 6.13 0.71
5.41 6.13 1.70
6.46 6.13 2.41

Pre -Development Drainage Area Calculations
Drainage Area =
Total Drainage Area:
Area Type
Open Space (Appling)
Open Space (Cecil)
Impervious Area, Existing Road
Offsite Existing Residential
Wooded
Notes on CN Values
Area Type
Open Space
Weighted C =
Impervious Area
Impervious Area
Residential District, 1-acre lots
Runoff
Storm 1 (2-yr/24-hr)
Storm 2 (2my, /24-hr)
Storm 3 (25-yr/24-hr)
DA-EX-B
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
202,844 SF = 4.66 AC
Area Area
SF Ac. CN
1561607 3.60 61
6,125 0.14 61
4,315 0.10 98
14,430 0.33 68
211367 0.49 55
61.65 Use 62
TR-55
CN Notes
61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
98 Asphalt or Concrete Pavement
85 Gravel
68 Cecil Sand clay loam (HSG B)
3.70 6.13 0.71
5.41 6.13 1.70
6.46 6.13 2.41

Pre -Development Drainage Area Calculations
Drainage Area =
Total Drainage Area.
DA-EX-C
271567 SF
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
Area Area
Area Type SF Ac. CN
Open Space 20,950 0.48 61
Impervious Area, Existing Road 6,617 0.15 98
rMwATMP
Weighted C =
Notes on CN Values
69.88 Use 70
TR-55
Area Type CN Notes
Open Space 61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
Woods 55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
Impervious Area 98 Asphalt or Concrete Pavement
Impervious Area 85 Gravel
Residential District, 1-acre lots 68 Cecil Sand clay loam (HSG B)
Runoff P (in) S (in) Q (in)
Storm 1 (2-yr/24-hr) 3.70 4.29 1.13
Storm 2 (2-yr/24-hr) 5.41 4.29 2.35
Storm 3 (25-yr/24-hr) 6.46 4.29 3.17

Post -Development Drainage Area Calculations
Drainage Area =
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
Total Drainage Area: 253,275 SF = 5.81 AC
Area Area
Area Type SF Ac. CN
Open Space (Appling) 181,650 4.17 61
Open Space (Cecil) 27,872 0.64 61
Impervious Area, existing road 4,459 0.10 98
Impervious Area, new road/drive 11,256 0.26 85
Offsite Existing Residential 28,038 0.64 68
Weighted C = 63.49 Use 64
Notes on CN Values
TR-55
Area Type CN Notes
Open Space 61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
Woods 55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
Impervious Area 98 Asphalt or Concrete Pavement
Impervious Area 85 Gravel
Residential District, 1-acre lots 68 Cecil Sand clay loam (HSG B)
Runoff P (in) S (in) Q (cfs)
Storm 1 (2-yr/24-hr) 3.70 5.63 0.81
Storm 2 (2-yr/24-hr) 5.41 5.63 1.85
Storm 3 (25-yr/24-hr) 6.46 5.63 2.60

Post -Development Drainage Area Calculations
Drainage Area =
Total Drainage Area:
Area Type
Open Space
Impervious Area, Existing pvmt
Impervious area, new road/drive
Wooded
Notes on CN Values
Area Type
Open Space
Weighted C =
Impervious Area
Impervious Area
Residential District, 1-acre lots
Runoff
Storm 1 (2-yr/24-hr)
Storm 2 (2-yr/24-hr)
Storm 3 (25-yr/24-hr)
105,207 SF
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
= 2.42 AC
Area Area
SF(Ace) CN
711665 1.65 61
1,468 0.03 98
101707 0.25 85
211367 0.49 55
62.74 Use 63
TR-55
CN Notes
61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
98 Asphalt or Concrete Pavement
85 Gravel
68 Cecil Sand clay loam (HSG B)
3.70 5.87 0.76
5.41 5.87 1.77
6.46 5.87 2.50

Post -Development Drainage Area Calculations
Drainage Area =
otal Drainage Area:
Area Type
Impervious area, substation pad
Notes on CN Values
Area Type
Open Space
Woods
Weighted C =
Impervious Area
Impervious Area
Residential District, 1-acre lots
Runoff
Storm 1 (2-yr/24-hr)
Storm 2 (2-yr/24-hr)
Storm 3 (25-yr/24-hr)
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
70,924 SF = 1.63 AC
Area Area
SF Ac. CN
701924 1.63 I 85
0.00 55
85.00 Use 85
TR-55
CN Notes
61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
98 Asphalt or Concrete Pavement
85 Gravel
68 Cecil Sand clay loam (HSG B)
3.70 1.76 2.19
5.41 1.76 3.75
6.46 1.76 4.74

Post -Development Drainage Area Calculations
Drainage Area =
DA-C
Project: Plato Lee Civil
Calcs by: S. Adams
Date: 5/18/2018
Total Drainage Area: 131407 SF = 0.31 AC
Area Area
Area Type SF Ac. CN
Open Space 91026 0.21 61
Impervious Area, Existing pvmt 41350 0.10 98
Impervious Area, new pvmt 31 0.001 98
Weighted C = 73.09 Use 74
Notes on CN Values
TR-55
Area Type CN Notes
Open Space 61 Appling Sand loam (HSG B) - good condition
61 Cecil Sand clay loam (HSG B) - good condition
Woods 55 Appling Sand loam (HSG B) - good condition
55 Pacolet-Bethleham complex (HSG B) - good condition
Impervious Area 98 Asphalt or Concrete Pavement
Impervious Area 85 Gravel
Residential District, 1-acre lots 68 Cecil Sand clay loam (HSG B)
Runoff P (in) S (in) Q (cfs)
Storm 1 (2-yr/24-hr) 3.70 3.51 1.38
Storm 2 (2-yr/24-hr) 5.41 3.51 2.70
Storm 3 (25-yr/24-hr) 6.46 3.51 3.58

TEMPORARY SEDIMENT TRAP DESIGN

Temporary Sediment Trap Capacity Requirements
Drainage Basin
Required
Provided
Required
Drainage
Area AC
Surface
Surface
Storage*
Provided
Basin
Phase
Phase
Phase
Area* (SF)
Area (SF)
(CF)
Storage (CF)
I
II
III
Temporary
East
4.83
3.90
n/a
5,655
7,900
17,280
25,700
Temporary
1.90
2.83
n/a
3,698
4X0
115304
15,800
West
*Minimum storage and surface area is provided for largest temporary drainage area during all
phases of erosion control when the temporary sediment traps will be in used.