SWA000209_Design Calculations_20230614

2S
1S
POST DEVEVELOPED
PREDEVELOPED
3P
POND
Routing Diagram for UNION WEST BLVD_STORMCAD CALCS
Reach
SubcatPond
Link
Prepared by Odom Engineering, Printed 3/29/2023
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 2
Project Notes
Copied 10 events from NC-MONROE 24-hr S1 storm

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 3
Rainfall Events Listing (selected events)
Event#EventStorm TypeCurveModeDurationB/BDepthAMC
Name(hours)(inches)
11-yrNC-MONROE 24-hr S11-yrDefault24.0012.922
22-yrNC-MONROE 24-hr S12-yrDefault24.0013.522
310-yrNC-MONROE 24-hr S110-yrDefault24.0015.142
425-yrNC-MONROE 24-hr S125-yrDefault24.0016.122
5100-yrNC-MONROE 24-hr S1100-yrDefault24.0017.712

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 4
Area Listing (all nodes)
AreaCNDescription
(acres)(subcatchment-numbers)
1.19461>75% Grass cover, Good, HSG B (2S)
0.64098Paved parking, HSG B (2S)
0.25098Roofs, HSG B (2S)
2.08066Woods, Poor, HSG B (1S)
4.16471TOTAL AREA

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 5
Soil Listing (all nodes)
AreaSoilSubcatchment
(acres)GroupNumbers
0.000HSG A
4.164HSG B1S, 2S
0.000HSG C
0.000HSG D
0.000Other
4.164TOTAL AREA

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 6
Ground Covers (all nodes)
HSG-AHSG-BHSG-CHSG-DOtherTotalGroundSubcatchment
(acres)(acres)(acres)(acres)(acres)(acres)CoverNumbers
0.0001.1940.0000.0000.0001.194>75% Grass cover, Good2S
0.0000.6400.0000.0000.0000.640Paved parking2S
0.0000.2500.0000.0000.0000.250Roofs2S
0.0002.0800.0000.0000.0002.080Woods, Poor1S
0.0004.1640.0000.0000.0004.164TOTAL AREA

UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 7
Pipe Listing (all nodes)
Line#NodeIn-InvertOut-InvertLengthSlopenWidthDiam/HeightInside-Fill
Number(feet)(feet)(feet)(ft/ft)(inches)(inches)(inches)
13P680.00679.7540.00.00630.0120.015.00.0

NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 8
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=2.080 ac 0.00% Impervious Runoff Depth>0.45"
Subcatchment 1S: PREDEVELOPED
Tc=5.0 min CN=66 Runoff=1.19 cfs 0.078 af
Runoff Area=2.084 ac 42.71% Impervious Runoff Depth>0.93"
Subcatchment 2S: POST DEVEVELOPED
Tc=5.0 min CN=77 Runoff=3.16 cfs 0.161 af
Peak Elev=681.96' Storage=7,884 cf Inflow=3.16 cfs 0.161 af
Pond 3P: POND
Outflow=0.34 cfs 0.076 af
Total Runoff Area = 4.164 ac Runoff Volume = 0.239 af Average Runoff Depth = 0.69"
78.63% Pervious = 3.274 ac 21.37% Impervious = 0.890 ac

NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 9
Summary for Subcatchment 1S: PREDEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=1.19 cfs @ 12.06 hrs, Volume=0.078 af, Depth>0.45"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
Area (ac)CNDescription
2.08066Woods, Poor, HSG B
2.080100.00% Pervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 1S: PREDEVELOPED
Hydrograph
Runoff
1.19 cfs
NC-MONROE 24-hr S1 1-yr
Rainfall=2.92"
1
Runoff Area=2.080 ac
Runoff Volume=0.078 af
Runoff Depth>0.45"
Tc=5.0 min
Flow (cfs)
CN=66
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 10
Summary for Subcatchment 2S: POST DEVEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=3.16 cfs @ 12.04 hrs, Volume=0.161 af, Depth>0.93"
Routed to Pond 3P : POND
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
Area (ac)CNDescription
0.25098Roofs, HSG B
0.64098Paved parking, HSG B
1.19461>75% Grass cover, Good, HSG B
2.08477Weighted Average
1.19457.29% Pervious Area
0.89042.71% Impervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 2S: POST DEVEVELOPED
Hydrograph
Runoff
3.16 cfs
NC-MONROE 24-hr S1 1-yr
3
Rainfall=2.92"
Runoff Area=2.084 ac
Runoff Volume=0.161 af
2
Runoff Depth>0.93"
Tc=5.0 min
Flow (cfs)
CN=77
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 11
Summary for Pond 3P: POND
Inflow Area =2.084 ac,42.71% Impervious, Inflow Depth > 0.93" for 1-yr event
Inflow=3.16 cfs @ 12.04 hrs, Volume=0.161 af
Outflow=0.34 cfs @ 12.68 hrs, Volume=0.076 af, Atten= 89%, Lag= 38.8 min
Primary=0.34 cfs @ 12.68 hrs, Volume=0.076 af
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Starting Elev= 680.10' Surf.Area= 1,819 sf Storage= 3,906 cf
Peak Elev= 681.96' @ 12.68 hrs Surf.Area= 2,484 sf Storage= 7,884 cf (3,978 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 98.5 min ( 903.1 - 804.6 )
VolumeInvertAvail.StorageStorage Description
#1677.00'14,525 cf Listed below
Custom Stage Data (Prismatic)
ElevationSurf.AreaInc.StoreCum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
677.0065300
678.001,029841841
679.001,4631,2462,087
680.001,7841,6243,711
681.002,1301,9575,668
682.002,5002,3157,983
683.002,8962,69810,681
684.004,7923,84414,525
DeviceRouting InvertOutlet Devices
#1Primary680.00'
15.0" Round Culvert
L= 40.0' CPP, projecting, no headwall, Ke= 0.900
Inlet / Outlet Invert= 680.00' / 679.75' S= 0.0063 '/' Cc= 0.900
n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf
#2Device 1680.10' C= 0.600 Limited to weir flow at low heads
1.0" Vert. Orifice/Grate
#3Device 1681.81' C= 0.600
10.0" W x 18.0" H Vert. Orifice/Grate X 2.00
Limited to weir flow at low heads
#4Device 1683.00' C= 0.600
36.0" x 36.0" Horiz. Orifice/Grate
Limited to weir flow at low heads
#5Primary683.65'
10.0' long + 3.0 '/' SideZ (Profile 1) Broad-Crested Rectangular Weir
Head (feet) 0.49 0.98 1.48
Coef. (English) 2.92 3.37 3.59
Max=0.34 cfs @ 12.68 hrs HW=681.96' (Free Discharge)
Primary OutFlow
(Passes 0.34 cfs of 5.38 cfs potential flow)
1=Culvert
(Orifice Controls 0.04 cfs @ 6.49 fps)
2=Orifice/Grate
(Orifice Controls 0.30 cfs @ 1.23 fps)
3=Orifice/Grate
( Controls 0.00 cfs)
4=Orifice/Grate
( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir

NC-MONROE 24-hr S1 1-yr Rainfall=2.92"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 12
Pond 3P: POND
Hydrograph
Inflow
Primary
3.16 cfs
Inflow Area=2.084 ac
3
Peak Elev=681.96'
Storage=7,884 cf
2
Flow (cfs)
1
0.34 cfs
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 13
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=2.080 ac 0.00% Impervious Runoff Depth>0.73"
Subcatchment 1S: PREDEVELOPED
Tc=5.0 min CN=66 Runoff=2.19 cfs 0.126 af
Runoff Area=2.084 ac 42.71% Impervious Runoff Depth>1.33"
Subcatchment 2S: POST DEVEVELOPED
Tc=5.0 min CN=77 Runoff=4.56 cfs 0.231 af
Peak Elev=682.18' Storage=8,482 cf Inflow=4.56 cfs 0.231 af
Pond 3P: POND
Outflow=1.27 cfs 0.146 af
Total Runoff Area = 4.164 ac Runoff Volume = 0.357 af Average Runoff Depth = 1.03"
78.63% Pervious = 3.274 ac 21.37% Impervious = 0.890 ac

NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 14
Summary for Subcatchment 1S: PREDEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=2.19 cfs @ 12.05 hrs, Volume=0.126 af, Depth>0.73"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
Area (ac)CNDescription
2.08066Woods, Poor, HSG B
2.080100.00% Pervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 1S: PREDEVELOPED
Hydrograph
Runoff
2.19 cfs
NC-MONROE 24-hr S1 2-yr
2
Rainfall=3.52"
Runoff Area=2.080 ac
Runoff Volume=0.126 af
Runoff Depth>0.73"
Tc=5.0 min
Flow (cfs)
1
CN=66
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 15
Summary for Subcatchment 2S: POST DEVEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=4.56 cfs @ 12.04 hrs, Volume=0.231 af, Depth>1.33"
Routed to Pond 3P : POND
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
Area (ac)CNDescription
0.25098Roofs, HSG B
0.64098Paved parking, HSG B
1.19461>75% Grass cover, Good, HSG B
2.08477Weighted Average
1.19457.29% Pervious Area
0.89042.71% Impervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 2S: POST DEVEVELOPED
Hydrograph
5Runoff
4.56 cfs
NC-MONROE 24-hr S1 2-yr
Rainfall=3.52"
4
Runoff Area=2.084 ac
Runoff Volume=0.231 af
3
Runoff Depth>1.33"
Tc=5.0 min
Flow (cfs)
CN=77
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 16
Summary for Pond 3P: POND
Inflow Area =2.084 ac,42.71% Impervious, Inflow Depth > 1.33" for 2-yr event
Inflow=4.56 cfs @ 12.04 hrs, Volume=0.231 af
Outflow=1.27 cfs @ 12.47 hrs, Volume=0.146 af, Atten= 72%, Lag= 25.8 min
Primary=1.27 cfs @ 12.47 hrs, Volume=0.146 af
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Starting Elev= 680.10' Surf.Area= 1,819 sf Storage= 3,906 cf
Peak Elev= 682.18' @ 12.47 hrs Surf.Area= 2,573 sf Storage= 8,482 cf (4,575 cf above start)
Plug-Flow detention time= 282.6 min calculated for 0.056 af (24% of inflow)
Center-of-Mass det. time= 57.9 min ( 855.2 - 797.3 )
VolumeInvertAvail.StorageStorage Description
#1677.00'14,525 cf Listed below
Custom Stage Data (Prismatic)
ElevationSurf.AreaInc.StoreCum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
677.0065300
678.001,029841841
679.001,4631,2462,087
680.001,7841,6243,711
681.002,1301,9575,668
682.002,5002,3157,983
683.002,8962,69810,681
684.004,7923,84414,525
DeviceRouting InvertOutlet Devices
#1Primary680.00'
15.0" Round Culvert
L= 40.0' CPP, projecting, no headwall, Ke= 0.900
Inlet / Outlet Invert= 680.00' / 679.75' S= 0.0063 '/' Cc= 0.900
n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf
#2Device 1680.10' C= 0.600 Limited to weir flow at low heads
1.0" Vert. Orifice/Grate
#3Device 1681.81' C= 0.600
10.0" W x 18.0" H Vert. Orifice/Grate X 2.00
Limited to weir flow at low heads
#4Device 1683.00' C= 0.600
36.0" x 36.0" Horiz. Orifice/Grate
Limited to weir flow at low heads
#5Primary683.65'
10.0' long + 3.0 '/' SideZ (Profile 1) Broad-Crested Rectangular Weir
Head (feet) 0.49 0.98 1.48
Coef. (English) 2.92 3.37 3.59
Max=1.26 cfs @ 12.47 hrs HW=682.18' (Free Discharge)
Primary OutFlow
(Passes 1.26 cfs of 5.83 cfs potential flow)
1=Culvert
(Orifice Controls 0.04 cfs @ 6.88 fps)
2=Orifice/Grate
(Orifice Controls 1.23 cfs @ 1.96 fps)
3=Orifice/Grate
( Controls 0.00 cfs)
4=Orifice/Grate
( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir

NC-MONROE 24-hr S1 2-yr Rainfall=3.52"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 17
Pond 3P: POND
Hydrograph
Inflow
Primary
4.56 cfs
5
Inflow Area=2.084 ac
Peak Elev=682.18'
4
Storage=8,482 cf
3
Flow (cfs)
2
1.27 cfs
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 18
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=2.080 ac 0.00% Impervious Runoff Depth>1.66"
Subcatchment 1S: PREDEVELOPED
Tc=5.0 min CN=66 Runoff=4.98 cfs 0.287 af
Runoff Area=2.084 ac 42.71% Impervious Runoff Depth>2.54"
Subcatchment 2S: POST DEVEVELOPED
Tc=5.0 min CN=77 Runoff=7.88 cfs 0.441 af
Peak Elev=682.73' Storage=9,948 cf Inflow=7.88 cfs 0.441 af
Pond 3P: POND
Outflow=4.75 cfs 0.354 af
Total Runoff Area = 4.164 ac Runoff Volume = 0.728 af Average Runoff Depth = 2.10"
78.63% Pervious = 3.274 ac 21.37% Impervious = 0.890 ac

NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 19
Summary for Subcatchment 1S: PREDEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=4.98 cfs @ 12.04 hrs, Volume=0.287 af, Depth>1.66"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
Area (ac)CNDescription
2.08066Woods, Poor, HSG B
2.080100.00% Pervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 1S: PREDEVELOPED
Hydrograph
Runoff
4.98 cfs
5
NC-MONROE 24-hr S1 10-yr
Rainfall=5.14"
Runoff Area=2.080 ac
4
Runoff Volume=0.287 af
Runoff Depth>1.66"
3
Tc=5.0 min
Flow (cfs)
CN=66
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 20
Summary for Subcatchment 2S: POST DEVEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=7.88 cfs @ 12.03 hrs, Volume=0.441 af, Depth>2.54"
Routed to Pond 3P : POND
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
Area (ac)CNDescription
0.25098Roofs, HSG B
0.64098Paved parking, HSG B
1.19461>75% Grass cover, Good, HSG B
2.08477Weighted Average
1.19457.29% Pervious Area
0.89042.71% Impervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 2S: POST DEVEVELOPED
Hydrograph
Runoff
7.88 cfs
8
NC-MONROE 24-hr S1 10-yr
Rainfall=5.14"
7
Runoff Area=2.084 ac
6
Runoff Volume=0.441 af
Runoff Depth>2.54"
5
Tc=5.0 min
4
Flow (cfs)
CN=77
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 21
Summary for Pond 3P: POND
Inflow Area =2.084 ac,42.71% Impervious, Inflow Depth > 2.54" for 10-yr event
Inflow=7.88 cfs @ 12.03 hrs, Volume=0.441 af
Outflow=4.75 cfs @ 12.14 hrs, Volume=0.354 af, Atten= 40%, Lag= 6.7 min
Primary=4.75 cfs @ 12.14 hrs, Volume=0.354 af
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Starting Elev= 680.10' Surf.Area= 1,819 sf Storage= 3,906 cf
Peak Elev= 682.73' @ 12.14 hrs Surf.Area= 2,789 sf Storage= 9,948 cf (6,042 cf above start)
Plug-Flow detention time= 135.5 min calculated for 0.264 af (60% of inflow)
Center-of-Mass det. time= 32.2 min ( 819.1 - 786.9 )
VolumeInvertAvail.StorageStorage Description
#1677.00'14,525 cf Listed below
Custom Stage Data (Prismatic)
ElevationSurf.AreaInc.StoreCum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
677.0065300
678.001,029841841
679.001,4631,2462,087
680.001,7841,6243,711
681.002,1301,9575,668
682.002,5002,3157,983
683.002,8962,69810,681
684.004,7923,84414,525
DeviceRouting InvertOutlet Devices
#1Primary680.00'
15.0" Round Culvert
L= 40.0' CPP, projecting, no headwall, Ke= 0.900
Inlet / Outlet Invert= 680.00' / 679.75' S= 0.0063 '/' Cc= 0.900
n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf
#2Device 1680.10' C= 0.600 Limited to weir flow at low heads
1.0" Vert. Orifice/Grate
#3Device 1681.81' C= 0.600
10.0" W x 18.0" H Vert. Orifice/Grate X 2.00
Limited to weir flow at low heads
#4Device 1683.00' C= 0.600
36.0" x 36.0" Horiz. Orifice/Grate
Limited to weir flow at low heads
#5Primary683.65'
10.0' long + 3.0 '/' SideZ (Profile 1) Broad-Crested Rectangular Weir
Head (feet) 0.49 0.98 1.48
Coef. (English) 2.92 3.37 3.59
Max=4.72 cfs @ 12.14 hrs HW=682.72' (Free Discharge)
Primary OutFlow
(Passes 4.72 cfs of 6.76 cfs potential flow)
1=Culvert
(Orifice Controls 0.04 cfs @ 7.74 fps)
2=Orifice/Grate
(Orifice Controls 4.68 cfs @ 3.07 fps)
3=Orifice/Grate
( Controls 0.00 cfs)
4=Orifice/Grate
( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir

NC-MONROE 24-hr S1 10-yr Rainfall=5.14"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 22
Pond 3P: POND
Hydrograph
Inflow
Primary
7.88 cfs
8
Inflow Area=2.084 ac
Peak Elev=682.73'
7
Storage=9,948 cf
6
4.75 cfs
5
4
Flow (cfs)
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 23
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=2.080 ac 0.00% Impervious Runoff Depth>2.31"
Subcatchment 1S: PREDEVELOPED
Tc=5.0 min CN=66 Runoff=6.62 cfs 0.400 af
Runoff Area=2.084 ac 42.71% Impervious Runoff Depth>3.32"
Subcatchment 2S: POST DEVEVELOPED
Tc=5.0 min CN=77 Runoff=9.65 cfs 0.577 af
Peak Elev=683.01' Storage=10,703 cf Inflow=9.65 cfs 0.577 af
Pond 3P: POND
Outflow=7.05 cfs 0.489 af
Total Runoff Area = 4.164 ac Runoff Volume = 0.977 af Average Runoff Depth = 2.81"
78.63% Pervious = 3.274 ac 21.37% Impervious = 0.890 ac

NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 24
Summary for Subcatchment 1S: PREDEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=6.62 cfs @ 12.04 hrs, Volume=0.400 af, Depth>2.31"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
Area (ac)CNDescription
2.08066Woods, Poor, HSG B
2.080100.00% Pervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 1S: PREDEVELOPED
Hydrograph
Runoff
7
6.62 cfs
NC-MONROE 24-hr S1 25-yr
6
Rainfall=6.12"
Runoff Area=2.080 ac
5
Runoff Volume=0.400 af
Runoff Depth>2.31"
4
Tc=5.0 min
Flow (cfs)
CN=66
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 25
Summary for Subcatchment 2S: POST DEVEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=9.65 cfs @ 12.03 hrs, Volume=0.577 af, Depth>3.32"
Routed to Pond 3P : POND
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
Area (ac)CNDescription
0.25098Roofs, HSG B
0.64098Paved parking, HSG B
1.19461>75% Grass cover, Good, HSG B
2.08477Weighted Average
1.19457.29% Pervious Area
0.89042.71% Impervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 2S: POST DEVEVELOPED
Hydrograph
Runoff
9.65 cfs
10
NC-MONROE 24-hr S1 25-yr
9
Rainfall=6.12"
8
Runoff Area=2.084 ac
7
Runoff Volume=0.577 af
Runoff Depth>3.32"
6
Tc=5.0 min
5
Flow (cfs)
CN=77
4
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 26
Summary for Pond 3P: POND
Inflow Area =2.084 ac,42.71% Impervious, Inflow Depth > 3.32" for 25-yr event
Inflow=9.65 cfs @ 12.03 hrs, Volume=0.577 af
Outflow=7.05 cfs @ 12.11 hrs, Volume=0.489 af, Atten= 27%, Lag= 4.8 min
Primary=7.05 cfs @ 12.11 hrs, Volume=0.489 af
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Starting Elev= 680.10' Surf.Area= 1,819 sf Storage= 3,906 cf
Peak Elev= 683.01' @ 12.11 hrs Surf.Area= 2,907 sf Storage= 10,703 cf (6,796 cf above start)
Plug-Flow detention time= 116.3 min calculated for 0.399 af (69% of inflow)
Center-of-Mass det. time= 28.6 min ( 811.0 - 782.3 )
VolumeInvertAvail.StorageStorage Description
#1677.00'14,525 cf Listed below
Custom Stage Data (Prismatic)
ElevationSurf.AreaInc.StoreCum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
677.0065300
678.001,029841841
679.001,4631,2462,087
680.001,7841,6243,711
681.002,1301,9575,668
682.002,5002,3157,983
683.002,8962,69810,681
684.004,7923,84414,525
DeviceRouting InvertOutlet Devices
#1Primary680.00'
15.0" Round Culvert
L= 40.0' CPP, projecting, no headwall, Ke= 0.900
Inlet / Outlet Invert= 680.00' / 679.75' S= 0.0063 '/' Cc= 0.900
n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf
#2Device 1680.10' C= 0.600 Limited to weir flow at low heads
1.0" Vert. Orifice/Grate
#3Device 1681.81' C= 0.600
10.0" W x 18.0" H Vert. Orifice/Grate X 2.00
Limited to weir flow at low heads
#4Device 1683.00' C= 0.600
36.0" x 36.0" Horiz. Orifice/Grate
Limited to weir flow at low heads
#5Primary683.65'
10.0' long + 3.0 '/' SideZ (Profile 1) Broad-Crested Rectangular Weir
Head (feet) 0.49 0.98 1.48
Coef. (English) 2.92 3.37 3.59
Max=6.94 cfs @ 12.11 hrs HW=682.99' (Free Discharge)
Primary OutFlow
(Passes 6.94 cfs of 7.18 cfs potential flow)
1=Culvert
(Orifice Controls 0.04 cfs @ 8.13 fps)
2=Orifice/Grate
(Orifice Controls 6.90 cfs @ 3.49 fps)
3=Orifice/Grate
( Controls 0.00 cfs)
4=Orifice/Grate
( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir

NC-MONROE 24-hr S1 25-yr Rainfall=6.12"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 27
Pond 3P: POND
Hydrograph
Inflow
Primary
9.65 cfs
10
Inflow Area=2.084 ac
9
Peak Elev=683.01'
8
Storage=10,703 cf
7.05 cfs
7
6
5
Flow (cfs)
4
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 28
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=2.080 ac 0.00% Impervious Runoff Depth>3.45"
Subcatchment 1S: PREDEVELOPED
Tc=5.0 min CN=66 Runoff=9.07 cfs 0.598 af
Runoff Area=2.084 ac 42.71% Impervious Runoff Depth>4.64"
Subcatchment 2S: POST DEVEVELOPED
Tc=5.0 min CN=77 Runoff=12.12 cfs 0.806 af
Peak Elev=683.32' Storage=11,923 cf Inflow=12.12 cfs 0.806 af
Pond 3P: POND
Outflow=7.66 cfs 0.717 af
Total Runoff Area = 4.164 ac Runoff Volume = 1.404 af Average Runoff Depth = 4.05"
78.63% Pervious = 3.274 ac 21.37% Impervious = 0.890 ac

NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 29
Summary for Subcatchment 1S: PREDEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=9.07 cfs @ 12.03 hrs, Volume=0.598 af, Depth>3.45"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
Area (ac)CNDescription
2.08066Woods, Poor, HSG B
2.080100.00% Pervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 1S: PREDEVELOPED
Hydrograph
10
Runoff
9.07 cfs
9
NC-MONROE 24-hr S1 100-yr
Rainfall=7.71"
8
Runoff Area=2.080 ac
7
Runoff Volume=0.598 af
Runoff Depth>3.45"
6
Tc=5.0 min
5
CN=66
Flow (cfs)
4
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 30
Summary for Subcatchment 2S: POST DEVEVELOPED
\[49\] Hint: Tc<2dt may require smaller dt
Runoff=12.12 cfs @ 12.03 hrs, Volume=0.806 af, Depth>4.64"
Routed to Pond 3P : POND
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
Area (ac)CNDescription
0.25098Roofs, HSG B
0.64098Paved parking, HSG B
1.19461>75% Grass cover, Good, HSG B
2.08477Weighted Average
1.19457.29% Pervious Area
0.89042.71% Impervious Area
TcLengthSlopeVelocityCapacityDescription
(min)(feet)(ft/ft)(ft/sec)(cfs)
5.0
Direct Entry,
Subcatchment 2S: POST DEVEVELOPED
Hydrograph
Runoff
13
12.12 cfs
12
NC-MONROE 24-hr S1 100-yr
11
Rainfall=7.71"
Runoff Area=2.084 ac
10
Runoff Volume=0.806 af
9
Runoff Depth>4.64"
8
Tc=5.0 min
7
CN=77
6
Flow (cfs)
5
4
3
2
1
0
567891011121314151617181920
Time (hours)

NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 31
Summary for Pond 3P: POND
Inflow Area =2.084 ac,42.71% Impervious, Inflow Depth > 4.64" for 100-yr event
Inflow=12.12 cfs @ 12.03 hrs, Volume=0.806 af
Outflow=7.66 cfs @ 12.13 hrs, Volume=0.717 af, Atten= 37%, Lag= 6.3 min
Primary=7.66 cfs @ 12.13 hrs, Volume=0.717 af
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Starting Elev= 680.10' Surf.Area= 1,819 sf Storage= 3,906 cf
Peak Elev= 683.32' @ 12.13 hrs Surf.Area= 3,509 sf Storage= 11,923 cf (8,016 cf above start)
Plug-Flow detention time= 100.3 min calculated for 0.626 af (78% of inflow)
Center-of-Mass det. time= 27.6 min ( 803.4 - 775.8 )
VolumeInvertAvail.StorageStorage Description
#1677.00'14,525 cf Listed below
Custom Stage Data (Prismatic)
ElevationSurf.AreaInc.StoreCum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
677.0065300
678.001,029841841
679.001,4631,2462,087
680.001,7841,6243,711
681.002,1301,9575,668
682.002,5002,3157,983
683.002,8962,69810,681
684.004,7923,84414,525
DeviceRouting InvertOutlet Devices
#1Primary680.00'
15.0" Round Culvert
L= 40.0' CPP, projecting, no headwall, Ke= 0.900
Inlet / Outlet Invert= 680.00' / 679.75' S= 0.0063 '/' Cc= 0.900
n= 0.012 Corrugated PP, smooth interior, Flow Area= 1.23 sf
#2Device 1680.10' C= 0.600 Limited to weir flow at low heads
1.0" Vert. Orifice/Grate
#3Device 1681.81' C= 0.600
10.0" W x 18.0" H Vert. Orifice/Grate X 2.00
Limited to weir flow at low heads
#4Device 1683.00' C= 0.600
36.0" x 36.0" Horiz. Orifice/Grate
Limited to weir flow at low heads
#5Primary683.65'
10.0' long + 3.0 '/' SideZ (Profile 1) Broad-Crested Rectangular Weir
Head (feet) 0.49 0.98 1.48
Coef. (English) 2.92 3.37 3.59
Max=7.65 cfs @ 12.13 hrs HW=683.32' (Free Discharge)
Primary OutFlow
(Inlet Controls 7.65 cfs @ 6.24 fps)
1=Culvert
(Passes < 0.05 cfs potential flow)
2=Orifice/Grate
(Passes < 9.88 cfs potential flow)
3=Orifice/Grate
(Passes < 6.95 cfs potential flow)
4=Orifice/Grate
( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir

NC-MONROE 24-hr S1 100-yr Rainfall=7.71"
UNION WEST BLVD_STORMCAD CALCS
Printed 3/29/2023
Prepared by Odom Engineering
HydroCAD® 10.20-2g s/n 08562 © 2022 HydroCAD Software Solutions LLC
Page 32
Pond 3P: POND
Hydrograph
Inflow
Primary
12.12 cfs
13
Inflow Area=2.084 ac
12
11
Peak Elev=683.32'
10
Storage=11,923 cf
9
7.66 cfs
8
7
6
Flow (cfs)
5
4
3
2
1
0
567891011121314151617181920
Time (hours)