SW6230103_Design Calculations_20230131

APPENDIX A
Computations
Minor System
Grass Conveyance Swales
,WO911"If Erosion Control
69AL �.
O4f41f

Culvert Report
Hydraflow Express Extension forAutoCAD® Civil 31® 2009 byAutodesk, Inc.
FES 104
Invert Elev Dn (ft)
= 199.03
Pipe Length (ft)
= 20.00
Slope (%)
= 3.00
Invert Elev Up (ft)
= 199.63
Rise (in)
= 18.0
Shape
= Cir
Span (in)
= 18.0
No. Barrels
= 1
n-Value
= 0.012
Inlet Edge
= Projecting
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.5
Embankment
Top Elevation (ft)
= 202.50
Top Width (ft)
= 18.00
Crest Wdth (ft)
= 10.00
Elev (ft)
203.00
202.00
201.00
200.00
199.00
FES 104
Wednesday, Sep 21 2022
Calculations
Qmin (cfs)
= 6.71
Qmax (cfs)
= 6.71
Tailwater Elev (ft)
= Normal
Highlighted
Qtotal (cfs)
= 6.71
Qpipe (cfs)
= 6.71
Qovertop (cfs)
= 0.00
Veloc Dn (ft/s)
= 8.35
Veloc Up (ft/s)
= 5.32
HGL Dn (ft)
= 199.73
HGL Up (ft)
= 200.64
Hw Elev (ft)
= 201.14
Hw/D (ft)
= 1.01
Flow Regime
= Inlet Control
Hw Depth (ft)
3.37
--
lMetcuntrnI
2 4 6 8
Ca Cuh+eft -- HGL
2.37
1.37
0.37
-0,k3
-1.63
10 12 14 16 18 20 22 24 26 28
- Embank Reach (ft)

Culvert Report
Hydraflow Express Extension forAutoCAD® Civil 3D® 2009 byAutodesk, Inc.
FES 204
Invert Elev Dn (ft)
= 201.34
Pipe Length (ft)
= 20.00
Slope (%)
= 3.00
Invert Elev Up (ft)
= 201.94
Rise (in)
= 18.0
Shape
= Cir
Span (in)
= 18.0
No. Barrels
= 1
n-Value
= 0.012
Inlet Edge
= Projecting
Coeff. K,M,c,Y,k
= 0.0045, 2, 0.0317, 0.69, 0.5
Embankment
Top Elevation (ft)
= 204.84
Top Width (ft)
= 18.00
Crest Width (ft)
= 10.00
Efev fiti
205.00
204.00
203,00
202.00
201-00
200.00
0 2 4
Cir Culvert
FES 204
Wednesday, Sep 212022
Calculations
Qmin (cfs)
= 6.53
Qmax (cfs)
= 6.53
Tailwater Elev (ft)
= Normal
Highlighted
Qtotal (cfs)
= 6.53
Qpipe (cfs)
= 6.53
Qovertop (cfs)
= 0.00
Veloc Dn (ft/s)
= 8.29
Veloc Up (ft/s)
= 5.26
HGL Dn (ft)
= 202.03
HGL Up (ft)
= 202.93
Hw Elev (ft)
= 203.42
Hw/D (ft)
= 0.99
Flow Regime
= Inlet Control
Hw Depth (ft)
3.06
k
£k „ffi ffill;�
b 8 to 12 14
— -- HGL-•---,- Embank
2.06
1.06
ROG
-0.94
-1.94
1fi 18 20 22 24 26 28
Reach (ft)

Permanent Channel # 1 => DA # PD 1
Calculate Flow - Rational Method
25-Yr Storm
Q25 = CIA C= 0,35.
1= 5.92 in/hr CALC Tc
Q25=
38.12 A= 18AO ac
Channel Slope=
0.00
Channel Depth=
2.50
Channel Bottom Width=
4,00
Side Slopes=
3.00
Velocity--
2.31
Soil Type 6-D
Sondy loam Slopes= 0-10%
Channel lining
Shear Calculation
T=yds y= 62.4 Ibs
dmter= 1.86.ft
T= 0.58032 Ibs/ft2 s= 0.005 ft/ft
Temporary= NAGS758N -
Permanent-- Foscue
Permanent Channel # 2 => DA # PD 2
Calculate Flow - Rational Method
25-Yr Storm
025 = CIA
C= 030
I= 8.99 in/hr
Q25 =
5.87 A= 2.20 ac
Channel S►ope=
1.60,11
Channel Depth=
2,50
Channel Bottom Width=
4.00'
Side Slopes=
3.01Y
Velo i =
3.97
Soil Types
sandy loam Slopes= 0-10%
Channel Lining
Shear Calculation
T=yds y= 62.4lbs
dmter= 0.7:' ft
T= 0.69888 Ibs/ft2 s= ' , , D." ft/ft
Temporary= MAW `
Permanent= FesCVE

Permanent Channel # 3 " => DA # 204
Calculate Flow - Rational Method
25-Yr Storm
Q25 = CIA
Q25= 6.53
Channel Slope=
1.00
Channel Depth=
1.00
Channel Bottom Width=
0.00
Side Slopes=
3.00
Veloci =
3.49
Soil Type 9
sandy loam
Channel Linine
Shear Calculation
T=yds
C= ' 0.35
1= 8.89in/hr
A= 2.10 ac
Slopes 0-1U � N°
T= 0.246481bs/ft2
Temporary= NAG S75BN
Permanent= Fescue
CALC Tc
y= 62.4 lbs
dwater= 0•79 ft
s= 0.005 ft/ft

U.S. Department of Agriculture
Natural Resources Conservation Service
FL-ENG-21 B
06104
TR 55 Worksheet 3: Time of Concentration (TJ or Travel Time (TJ
Project: Carter Farms Subdivison
Location: Hoke County, NC
Check one: V Present Developed
Check one: V Tc Tt
Designed By: MTB Date:
Checked By: MDA
through subarea DA #104
Date:
NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic,
or description of flow segments.
Sheet Flow (Applicable to T, only)
1. Surface description (Table 3-1) __...............
2. Manning's roughness coeff., n (Table 3-1) ...
3. Flow length, L (total L < 100 ft) .....................
4. Two-year 24-hour rainfall, P2.........................
5. Land slope, s................................................
6. Tt = 0.007 (nL) Of Compute Tt ...
P20.5 s0.4
Shallow Concetrated Flow
Segment ID I 1
7. Surface description (paved or unpaved) .............. _...................
8. Flow length, L.............................. __......... ........................... ... ft
9. Watercourse slope, s........................................................... ft/ft
10. Average velocity, V (Figure 3-1).......................................... ft/s
11. Tt = L Compute Tt ......................... hr
3600 V
Channel Flow
12. Cross sectional flow area, a ......................
13. Wetted perimeter, P,N.................................
14. Hydraulic radius, r = a Compute r ..........
P,
GRASS
0.04
100
0.1
0.050
0.18
+
z
UNPAVED
557
0.013
1.9
0.08
+
Segment ID
..................... ftz 0.0
.................... ft 0.0
...... I ... I........ ft
15. Channel Slope, s............................................................ ft/ft
16. Manning's Roughness Coeff., n............................................
17. V = 1.49 /3 s1/2 Compute V ...................... ft!s
n
18. Flow length, L...................................................................... ft
19. Tt = L Compute Tt.................................... hr
3600 V
20. Watershed or subarea T, or Tt (add Tt in steps 6, 11, and 19
...................................................... hr 0.26
0.26= 15.6 mins

Chapter 3 Time of Concentration and Travel Time Technical Release 55
Urban Hydroloa for Small Watersheds
Figure 3-1 Average velocities for estimating travel time forshaltow concentrated flow
.20
10
0
as
06
0
.04
ON
.01
.005 L
I
2 4 6 10 20
1.9
Average veloolty (ft/sec)
.3--2 (210AVI-TR-55, Second FA, June 1986)

Pre POI #01
POI#01 Pre
Developmemt
SCM01
SCM 1 DA
SCM #01
C,9ucat Reach on LIreIC

Carter Farm Subdivision
PC01 Type 1124-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment Pre POI #01: POI#01 Pre Developmemt
Runoff = 2.96 cfs @ 12.02 hrs, Volume= 0.489 af, Depth= 0.32"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-Year Rainfall=5.52"
Area (ac) CN Description
0.000
39
Woods
18.400
39
Grass
0.000
90
Pavement
0.000
90
Sidewalk
0.080
90
Buidling
18.480
39
Weighted Average
18.480
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: POI#01 Pre Developmemt
Hydrograph
2.96 cfs -
3--Type 1124-h r
10-Year rainfall=5.52"
3 Runoff Area=18.480 ac
2
Runoff Volume=-0.489 of
Runoff Depth=0.32"
Tc=5.0 min
- DN=39
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 16.66 cfs @ 11.99 hrs, Volume= 1.035 af, Depth= 0.67"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 10-Year Rainfall=5.52"
Area (ac) CN Description
2.390 90 Impervious
16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
_ Runoff
1s
1 6.6 6 cfs - -
'
16 r Type 1124-h r =
15: - - -14-Year Rainfall=5-;52"
14 -
13- _ - _------ --'- Runoff area=18.400 aG
12: Runoff ilolume=1.035 of
r
- 11- - T T -
- Runoff Depth=0.67" -
9 r-, - - -.- -,- --
T r LLTc 5.0 min
8 - -
7-
-r - - -, CN=46
6 -T +4--1-
5: — +
2-
1
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 4
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 0.67" for 10-Year event
Inflow - 16.66 cfs @ 11.99 hrs, Volume= 1.035 of
Outflow = 1.43 cfs @ 13.95 hrs, Volume= 1.034 af, Atten= 91 %, Lag= 117.5 min
Primary = 0.47 cfs @ 13.95 hrs, Volume= 0.894 of
Secondary = 0.96 cfs @ 13.95 hrs, Volume= 0.140 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,269 cf
Peak Elev= 199.03' @ 13.95 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug -Flow detention time= 591.6 min calculated for 0.983 of (95% of inflow)
Center -of -Mass det. time= 530.0 min ( 1,451.4 - 921.4)
Volume Invert Avail.Stora-ge Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) M (cubic -feet) (cubic -feet)
194.00 3,765 0.0 0 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.500 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation=190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.47 cfs @ 13.95 hrs HW=199.03' (Free Discharge)
'L1=Exfiltration ( Controls 0.47 cfs)
Secondary OutFlow Max=0.74 cfs @ 13.95 hrs HW=199.03' (Free Discharge)
2=Broad-Crested Rectangular Weir (Weir Controls 0.74 cfs @ 0.44 fps)

Carter Farm Subdivision
PC01 Type 11 24-hr 10-Year Rainfall=5.52"
Prepared by Toshiba Printed 9/21/2022
HydroCAD® 10.00-20 s/n 07811 0 2017 HydroCAD Software Solutions LLC Page 5
Pond 01 P: SCM #01
Hydrograph
16.66 Cfs
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)
D Inflow
;� Outflow
Primary
0 Secondary

Carter Farm Subdivision
PC01 Type /l 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 6
Summary for Subcatchment Pre POI #01: POI#01 Pre Developmemt
Runoff = 13.80 cfs @ 12.00 hrs, Volume= 1.007 af, Depth= 0.65"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type 11 24-hr 25-Year Rainfall=6.67"
Area (ac) CN Description
0.000
39
Woods
18.400
39
Grass
0.000
90
Pavement
0.000
90
Sidewalk
0.080
90
Buidling
18.480
39
Weighted Average
18.480
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: POI#01 Pre Developmemt
Hydrograph
',
13.80 cfs - - - - - -
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 33.74 cfs @ 11.98 hrs, Volume= 1.783 af, Depth= 1.16"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 25-Year Rainfall=6.67"
Area (ac) CN Description
2.390 90 Impervious
16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
33.74 Cfs Runoff
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 02017 HydroCAD Software Solutions LLC Page 8
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 1.16" for 25-Year event
Inflow = 33.74 cfs @ 11.98 hrs, Volume= 1.783 of
Outflow = 15.52 cfs @ 12.10 hrs, Volume= 1.783 af, Atten= 54%, Lag= 7.3 min
Primary = 0.48 cfs @ 12.10 hrs, Volume= 0.914 of
Secondary = 15.03 cfs @ 12.10 hrs, Volume= 0.869 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,259 cf
Peak Elev= 199.23' @ 12.11 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug -Flow detention time= 345.0 min calculated for 1.730 of (97% of inflow)
Center -of -Mass det. time= 316.1 min ( 1,213.0 - 896.8 )
Volume Invert Avail.Storage Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) (%) (cubic -feet) (cubic -feet)
194.00 3,765 0.0 0 - 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.500 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation = 190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
rimary OutFlow Max=0.48 cfs @ 12.10 hrs HW=199.23' (Free Discharge)
1=Exfiltration ( Controls 0.48 cfs)
Secondary OutFlow Max=14.54 cfs @ 12.10 hrs HW=199.22' (Free Discharge)
2=113road-Crested Rectangular Weir (Weir Controls 14.54 cfs @ 1.18 fps)

Carter Farm Subdivision
PC01 Type 11 24-hr 25-Year Rainfall=6.67"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 9
Pond 01 P: SCM #01
Hydrograph
33.74 cfs -
outflow
- -- /�Prima
Inflow Area- A
aCi,
- -' - 18.400 _
iSecondary
36
Elev=199.23' - -
Pea
34k
- -1 + r i- - -i -4 1-
32
--Storage=21-,549 cf, -
30-
28_'F
t i i- 7 ,- -! _ » - -
26 :
_ r
- - - -: -r - - - . - -
24- '
- - - -
! i a t
z2
15.52 cfs
20-
0 1 s �15,03
cfsAL
LL 16
- 1
14 -
12�
10
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type 1124-hr 100-Year Rainfall=8.60°
Prepared by Toshiba Printed 9/21/2022
HydroCAD® 10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 10
Summary for Subcatchment Pre POI #01: POI#01 Pre Developmemt
Runoff - 40.53 cfs @ 11.98 hrs, Volume= 2.184 af, Depth= 1.42"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type 11 24-hr 100-Year Rainfall=8.60"
Area (ac) CN Description
0.000
39
Woods
18.400
39
Grass
0.000
90
Pavement
0.000
90
Sidewalk
* _ 0.080
90
Buidling
18.480
39
Weighted Average
18.480
100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment Pre POI #01: POI#01 Pre Developmemt
Hydrograph
40.53 cfs
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 11
Summary for Subcatchment SCM01: SCM 01 DA
Runoff = 68.81 cfs @ 11.97 hrs, Volume= 3.331 af, Depth= 2.17"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-Year Rainfall=8.60"
Area (ac) CN Description
2.390 90 Impervious
" 16.010 39 Pervious
18.400 46 Weighted Average
18.400 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment SCM01: SCM 01 DA
Hydrograph
75 — - Runoff
68.81 cfs _ -
70
- - Type it 24-hr
65-
60= 100 Year Rainfali=$:60"
55-_'
Runoff Area=18.400 ac --
50 .
45
Runoff-Volume=3.331 of -
,.. _ -
w
40 RunoffDepth=2.17'"
LL 35 Tc=5.0 min
30
C N-46
25=
20
15
10
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Carter Farm Subdivision
PC01 Type/1 24-hr 100-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCADO 10.00-20 s/n 07811 © 2017 HydroCAD Software Solutions LLC Page 12
Summary for Pond 01 P: SCM #01
Inflow Area = 18.400 ac, 0.00% Impervious, Inflow Depth = 2.17" for 100-Year event
Inflow - 68.81 cfs @ 11.97 hrs, Volume= 3.331 of
Outflow = 81.44 cfs @ 11.99 hrs, Volume= 3.331 af, Atten= 0%, Lag= 1.3 min
Primary = 0.50 cfs @ 11.99 hrs, Volume= 0.921 of
Secondary = 80.94 cfs @ 11.99 hrs, Volume= 2.410 of
Routing by Stor-Ind method, Time Span= 1.00-72.00 hrs, dt= 0.05 hrs
Starting Elev= 197.00' Surf.Area= 3,765 sf Storage= 2,259 cf
Peak Elev= 199.67' @ 11.99 hrs Surf.Area= 15,748 sf Storage= 21,549 cf (19,290 cf above start)
Plug -Flow detention time= 184.6 min calculated for 3.279 of (98% of inflow)
Center -of -Mass det. time= 170.3 min ( 1,043.4 - 873.2)
Volume Invert Avail.Storage Storage Description
#1 194.00' 21,549 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Voids Inc.Store Cum.Store
(feet) (sq-ft) (%) (cubic -feet) (cubic -feet)
194.00 3,765 0.0 0 0
195.00 3,765 20.0 753 753
196.00 3,765 20.0 753 1,506
197.00 3,765 20.0 753 2,259
198.00 9,533 100.0 6,649 8,908
199.00 15,748 100.0 12,641 21,549
Device Routing Invert Outlet Devices
#1 Primary 197.00' 1.600 in/hr Exfiltration over Surface area above 197.00'
Conductivity to Groundwater Elevation = 190.00'
Excluded Surface area = 3,765 sf
#2 Secondary 199.00' 55.0' long x 10.0' breadth Broad -Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64
Primary OutFlow Max=0.50 cfs @ 11.99 hrs HW=199.63' (Free Discharge)
L1=Exfiltration ( Controls 0.50 cfs)
$econdary OutFlow Max=74.67 cfs @ 11.99 hrs HW=199.63' (Free Discharge)
2=Broad-Crested Rectangular Weir (Weir Controls 74.67 cfs @ 2.15 fps)

Carter Farm Subdivision
PC01 Type 11 24-hr 900-Year Rainfall=8.60"
Prepared by Toshiba Printed 9/21/2022
HydroCAD®10.00-20 s/n 07811 OO 2017 HydroCAD Software Solutions LLC Page 13
Pond 01 P: SCM #01
Hydrograph
_, r r
®Inflow
---
81.44 CfS
.-
- - A
Inflow aC;
D Outflow
® Primary
90
85
80.94
Cfs Cfs
,Area=1.8.400
-Peak E1ev=199.67'
® Secondary
60
-
_
75m
,
-Storage=21_,549 cf ..
70
-
65R.
.r
60-
55'
50
U
"
,`
-
-' -' -
3 45
-
0
u. 40
35
30
;.
25
-,
15
-,
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
Time (hours)

Sediment Basin # 1
Calculate Flow - Rational Method
10-Yr Storm
Qla = CIA
2-Yr Storm
Q2 = CIA
Qlo = 30.88
Q2 = 23.92
Calculate Reauired Surface Area
SA=Qlo x 435 sf/cfs
SA= 13433.93 ft2
Side Slopes = 3.00 :1
Pond Depth= 4.00 ft
Basin Dims (Per SA)
C= 0.30
1= 7.98
A= 12.90
C= 0.30
1= 6.18
A= 12.90
Q10 = 30.88
25-Yr Storm
Q25 = CIA
Q25 —
Top =
79.00 x
213.00 =
Weir =
67.00 x
201.00 =
Bottom =
43.00 x
177.00 =
Volume Required
VR=Ax1800 cf/ac
VR= 23220.00 ft3
Volume Proposed
Vp=((Top Area + Bottom Area)/2)xD
VP= 48876.00 ft3
Skimmer Sizing
Calculate Dewater Time
A= 12.90 ac
Top= 16827.00 sf
Bottom= 7611.00 sf
D= 4.00 ft
34.40
16827 ft2
13467 ft2
7611 ft2
C= 0.30
1= 8.89
A= 12.90

Qd=V/Td
Qd= 4644.00 cf/day
Calculate Orifice Diameter
D=sgrt((Qd/(2310sgrt(h)))
D= 1.87
Use 4
Principle Spillway Sizing_
L=Q2/(cH"')
L= 4.20 ft
Riser Sizing
V= 23220.00 ft3
Td= 5 3-5 days typ
Qd= 4644.00
h= 0.33
" Skimmer w/ 1.87 " Orifice
L= ? ft
H= 1.50 ft
c= 3.10
C=pi X D
C=
4.20 ft
pi=
3.14
D=
16.05 in
D=
? ft
Material=
CMP.
Use
24.00 "CMP Riser
Barrel Sizing
Q2= CA X sgrt(2gh)
C=
0.60
A= ?
sf
A=
2.12
Q2=
23.92 cfs
h=
5.50 ft
A=pi X r2
g=
32.20 ft/s
A= 19.71 in
Material= CMP
Use M00 "CMP Barrel
Size Riser/Barrel Base
Calculate Bouyance Force on Riser

Cross -sectional area
A=(pi x r2) x 2
A= 6.28 sf
Riser Volume
V=A x L
V= 25.12
Bouyance Force
FB=qV
FB= 1567.49lbs/cf
r= 1.00
A= 6.28
L= 4.00
q= 62.40lbs
V= 25.12 ft3
Concrete Base Sizing
(Concrete = 120 Ibs/cf) - (weight of water = 62.4 Ibs/cf) = 57.6 Ibs/cf x 1.1 SAFETY FACTOR
Base Volume 29.93 cf
Base Dims = 5.47 ft
x 5.47 ft x 1.00 ft
Weir Sizing
Per AutoCad Hydraflow Software
L=
10.00 ft
D=
2.00 ft
dwater=
1.00 ft
Q25=
34.40 cfs
Velocity=
3.37 ft/s
Weir Lining
Shear Calculation
T=yds y= 62.4lbs
dwater= 1 ft
T= 0.624 Ibs/ft2 s= 0.01 ft/ft
Required Liner= Class A Rip Rap
Proposed Liner= Class A Rip Rap

Temporary Diversion/Berm #
1 => DA # EC401
Calculate Flow - Rational Method
25-YrStorm
Q25 = CIA
C= 0,40
1*= 5.92 in/hr *Intensity perTc
Q25 = 23.68
A= 10.00 ac
Channel Slope = 0.20
Channel Depth = 2.50
Bottom Width = 4.00
Side Slopes = 3.00
Velocity = 3A2
Soil Type @ Loamy Sand Slopes = 040%
Channel Linin¢
Shear Calculation
T=yds
y= 62.4 Ibs
d-., 1.3: ft
T= 0.4056 Ibs/ft2 S= 0.005 ft/ft
Temporary= NAG S7$BN
Permanent= NAG MON
Temporary Diversion/Berm #.- 2 => DA # EC402
Calculate Flow - Rational Method
25-Yr Storm
Q25 = CIA
C= 0.40
I*= 6.38 in/hr *Intensity per Tc
Q25=
4.59 A= 1.80 a
Channel Slope =
0.00
Channel Depth=
2.OD
Bottom Width=
4.00
Side Slopes =
3,00
Veloci =
1.40
Soil Type kD Loamy Sand Slopes= 0-10%
Channel Linine
Shear Calculation
T=yds y= 62.4lbs
dwater= 1.05ft
T= 0.3276 1bS/ft2 S= 0.005 ft/ft
Temporary= NAG S75iN
Permanent= NAGS758N

Barrel Outlet Protection #1
New York Method 8.06.5 Manual
Diameter of Barrel =
Velocity=
Zone=
18.001, La= 8 ft
5.5ft/s W= 6ft
1 Stone Diameter= Class a
Stone d= 12 in