SW3170402 (4)

(
YARBROUGH—WILLIAMS & HOULE, INC.
Planning • Surveying • Engineering
NCBELS C-0475
SC COA332
STORM DRAINAGE CALCULATIONS
AND
CORRUGATED METAL
PIPE DETENTION
AT
Henn Project
/2.;
.n� m
J m
1
41.1;i1SIEA:413.6.:11 006
14906 41, 9A
IGOo9astv�Pv3 ®t� •a,�
November 21, 2016
Rev. March 29. 2017
• Storm Drainage Calculations
• Erosion Control Calculations
• Detention Calculations (Hydrocad /
Detention Results)
r-�
® fax [phone]
� 730 Windsor Oak Court, Charlotte,NC 28273 • P.O. Box 1198,Pineville,NC 28134 • 704.556.1990 0

Skimmer Size Calculation
Skimmer Size Head on Orifice
_ 1.5 0 125
2 0 167
25 0208
3 0.25
4 0.333
5 0.333
6 0.417
8 0 5
Dewatering Dewatering _
Skimmer Head on Volume of water time in days Flow Rate Orifice Dia Orifice Dia
immer Basin# Size(in) Orifice(ft) V (cf) td(days) Qd(cf/day) Calc.D (in) Actual D(in)
1 15 013 6,201 3 2067 1.59 1.5
I '

P. O .BOX 7007 tjJ
c,
‘cz-
CHARLOTTE,N.C. 28241
Phone: [phone] YARBROUGH-WILLIAMS & HOULE, INC.
Fax: [phone] Planning • Surveying • Engineering
PROJECT NAME
Henn Project
DATE : Oct. 24, 2016
NEW YORK STANDARDS RIP RAP APRON NOMOGRAPH [ Tw < 0.5(Do) I
R.R.I.F.P = Rip Rap For Inlet Protection
RIP RAP APRON DESIGN
MINIMUM RIP RAP RIP RAP OUTLET
STRUCTURE VEL. APRON RIP RAP DEPTH(IN) FLOW
NO. FT/SEC DIMENSIONS D 50(IN) W/FABRIC CFS
WIDTH X LENGTH
202 134 40.5 X 35.0 12.0 18.0 251.9

YARBROUGH-WILLIAMS & HOULE, INC.
Planning • Surveying • Engineering
P O.BOX 1198
MATTHEWS,NC 28241
Phone: [phone]
Dry Pond Calculations Fax: [phone]
Date: Nov.21,2016 Rev. 3 27.17
PROJECT. Henn Project, Detention with Corrugated Metal Pipe
Results of Preliminary Hydrologic Calculations
(From Computer Model Results Using SCS Hydrologic Procedures)
Condition Runoff Q 1-year Q 2-year 010-year
cfs cfs cfs
Pre-development Flow 01111111111111111111111=
Post Development Detained 011111111MiVINMONEIVIIIII ird

(47S) I> 443\
Site Pipe Storage
4ubc Reach Pon Link Routing Diagram for Henn Project Underground Detention
Prepared by Microsoft, Printed 3/30/2017
HydroCAD®10 00 s/n 05047 ©2013 HydroCAD Software Solutions LLC
•

Henn Project Underground Detention Charlotte 6-hr 1 INCH linch Rainfall=1.00"
Prepared by Microsoft Printed 3/30/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 47S: Site
Runoff = 1.57 cfs @ 3.11 hrs, Volume= 0.060 af, Depth= 0.79"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 1 INCH 1inch Rainfall=1.00"
Area (ac) CN Description
* 0.910 98
0.910 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,Tc
-_ Subcatchment 475: Site
Hydrograph
' 1 57 cfs —Runoff
Charlotte 6-hr
1 INCH
1 inch Rainfall=1 MO"
Runoff Area®0.910 ac
Runoff Volume=0.060 af
LL
Runoff Depth=0.79"
Tc=5.0 min
CN=98
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)

Henn Project Underground Detention Charlotte 6-hr 1 INCH linch Rainfall=1.00"
Prepared by Microsoft Printed 3/30/2017
HydroCAD® 10 00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 3
Summary for Pond 48P: Pipe Storage
Inflow Area = 0.910 ac,100.00% Impervious, Inflow Depth = 0.79" for 1inch event
Inflow = 1.57 cfs @ 3.11 hrs, Volume= 0.060 of
Outflow = 0.10 cfs @ 2.65 hrs, Volume= 0.060 af, Atten= 94%, Lag= 0.0 min
Primary = 0.10 cfs @ 2.65 hrs, Volume= 0.060 af
-
Routing by Stor-Ind method, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs/3
Peak Elev= 599.99' @ 3.93 hrs Surf.Area= 0 sf Storage= 1,570 cf
Plug-Flow detention time= 147.6 min calculated for 0.060 af(100% of inflow)
Center-of-Mass det. time= 147.5 min ( 348.3-200.8)
Volume Invert Avail.Storage Storage Description
#1 598.00' 8,093 cf Custom Stage Data Listed below
Elevation Cum.Store
(feet) (cubic-feet)
598.00 0
599.00 584
600.00 1,582
601.00 2,772
602.00 4,046
603.00 5,321
604.00 6,511
605.00 7,509
606.00 8,093
Device Routing Invert Outlet Devices
#1 Primary 596.50' 15.0" Round Culvert L= 10.6' Ke= 0.500
Inlet/Outlet Invert= 596.50' /596.00' S= 0.0472'/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 598.00' 0.100 cfs Constant Flow/Skimmer
#3 Device 1 602.40' 4.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 604.20' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=0.10 cfs @ 2.65 hrs HW=598.08' (Free Discharge)
L1 Culvert (Passes 0.10 cfs of 5.79 cfs potential flow)
-2=Constant Flow/Skimmer (Constant Controls 0.10 cfs)
-3=Orifice/Grate ( Controls 0.00 cfs)
-4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)

Henn Project Underground Detention Charlotte 6-hr 1 INCH finch Rainfall=1.00"
Prepared by Microsoft Printed 3/30/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 4
Pond 48P: Pipe Storage
Hydrograph
1.57 cfs ( —Inflow II
—Pnma
ry
Inflow Area=0.910 ac
Peak Elev=599.99'
Storage=1 ,570 cf
• 1_
✓ 4
o• _
LL
I 0 10 cfs
0 I)
0 5 10 15 •20 25 • 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)

Henn Project Underground Detention Type 1124-hr 2 yr 24 hr Rainfall=3.12"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 1
Summary for Subcatchment 49S: Pre-Dev.
Runoff = 0.41 cfs @ 12.02 hrs, Volume= 0.028 af, Depth= 0.41"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Type II 24-hr 2 yr 24 hr Rainfall=3.12"
Area (ac) CN Description
0.810 61 >75% Grass cover, Good, HSG B
0.810 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.7 150 0.0200 0.44 Sheet Flow, Pre-Dev
Fallow n= 0.050 P2= 3.12"
1.8 130 0.0300 1.21 Shallow Concentrated Flow, Pre-Dev.
Short Grass Pasture Kv= 7.0 fps
7.5 280 Total
I

Henn Project Underground Detention Type 1124-hr 10 yr 24 hr Rainfall=4.80"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 49S: Pre-Dev.
Runoff = 1.61 cfs @ 12.00 hrs, Volume= 0.084 af, Depth= 1.25"
Runoff by SCS TR-20 method, UH=SCS,Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Type II 24-hr 10 yr 24 hr Rainfall=4.80"
Area (ac) CN Description
0.810 61 >75% Grass cover, Good, HSG B
0.810 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)_
5.7 150 0.0200 0.44 Sheet Flow, Pre-Dev
' Fallow n= 0.050 P2= 3.12"
1.8 130 0.0300 1.21 Shallow Concentrated Flow, Pre-Dev.
Short Grass Pasture Kv= 7.0 fps
7.5 280 Total

<47S>
N /4P
Site Pipe Storage
Subcat Reach Pon Link Routing Diagram for Henn Project Underground Detention
Prepared by Microsoft, Printed 3/29/2017
HydroCAD®10 00 s/n 05047 ©2013 HydroCAD Software Solutions LLC

•
Henn Project Underground Detention Charlotte 24-hr 1-yr 1 yr 24 hr Rainfall=2.58"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 47S: Site
Runoff = 2.81 cfs @ 11.98 hrs, Volume= 0.178 af, Depth= 2.35"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs •
Charlotte 24-hr 1-yr 1 yr 24 hr Rainfall=2.58"
Area (ac) CN Description
* 0.910 98
0.910 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Tc
Subcatchment 47S: Site
Hydrograph
3-
2.81 cfs —Runoff
Charlotte - 1-yr
1 yr 24 hr Rainfall24hr=2.58"
2- Runoff Area=0.910 ac
Runoff Volume=0.178 of
LL _ Runoff Depth=2.35"
Tc=5.0 min
1- CN=98
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)
� 1

Henn Project Underground Detention Charlotte 24-hr 1-yr 1 yr 24 hr Rainfall=2.58"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 3
Summary for Pond 48P: Pipe Storage
Inflow Area = 0.910 ac,100.00% Impervious, Inflow Depth = 2.35" for 1 yr 24 hr event
Inflow = 2.81 cfs @ 11.98 hrs, Volume= 0.178 of
Outflow = 0.10 cfs @ 10.55 hrs, Volume= 0.178 af, Atten= 96%, Lag= 0.0 min
Primary = 0.10 cfs @ 10.55 hrs, Volume= 0.178 af
Routing by Stor-Ind method, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs/3
Peak Elev= 601.89' @ 13.85 hrs Surf.Area= 0 sf Storage= 3,910 cf
Plug-Flow detention time= 335.6 min calculated for 0.178 af(100% of inflow)
Center-of-Mass det. time= 335.6 min ( 1,094.6- 759.0 )
Volume Invert Avail.Storage Storage Description
#1 598.00' 8,093 cf Custom Stage Data Listed below
Elevation Cum.Store
(feet) (cubic-feet)
598.00 0
599.00 584
600.00 1,582
601.00 2,772
602.00 4,046
603.00 5,321
604.00 6,511
605.00 7,509
606.00 8,093
Device Routing Invert Outlet Devices
#1 Primary 596.50' 15.0" Round Culvert L= 10.6' Ke= 0.500
Inlet/Outlet Invert= 596.50'/596.00' S= 0.0472'/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 598.00' 0.100 cfs Constant Flow/Skimmer
#3 Device 1 602.40' 4.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 604.20' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=0.10 cfs @ 10.55 hrs HW=598.08' (Free Discharge)
L.=Culvert (Passes 0.10 cfs of 5.78 cfs potential flow)
-2=Constant Flow/Skimmer (Constant Controls 0.10 cfs)
-3=Orifice/Grate ( Controls 0.00 cfs)
-4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)

Henn Project Underground Detention Charlotte 24-hr, 1-yr 1 yr 24 hr Rainfall=2.58"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 4
Pond 48P: Pipe Storage
Hydrograph
3-
2 81 cfs
Inflow
—Pnmary
Inflow Area=0.910 ac
Peak Elev=601.89'
2- Storage=3,910 cf
a
O _
LL
I -
•
I _
0 10 cfs
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)
I

Henn Project Underground Detention Type 11 24-hr 2 yr 24 hr Rainfall=3.12"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment 47S: Site
Runoff = 4.05 cfs @ 11.95 hrs, Volume= 0.219 af, Depth= 2.89"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Type II 24-hr 2 yr 24 hr Rainfall=3.12"
Area (ac) CN Description
* 0.910 98
0.910 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,Tc
Subcatchment 47S: Site
Hydrograph
4 05 cfs —Runoff
4-
Type 1124-h r
2 yr 24 hr Rainfall=3.12"
3-- Runoff Area=0.310 ac
Runoff Volume=0.219 af
- Runoff De th=2.89"
u. 2- M1
Tc=5.Q min
CN=98
1-
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 65 90 95 100
Time (hours)
1
i _

Henn Project Underground Detention Type 11 24-hr 2 yr 24 hr Rainfall=3.12"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 6
Summary for Pond 48P: Pipe Storage
Inflow Area = 0.910 ac,100.00% Impervious, Inflow Depth = 2.89" for 2 yr 24 hr event
Inflow = 4.05 cfs @ 11.95 hrs, Volume= 0.219 af
Outflow = 0.18 cfs @ 13.07 hrs, Volume= 0.219 af, Atten= 96%, Lag= 67.1 min
Primary = 0.18 cfs @ 13.07 hrs, Volume= 0.219 af
'Routing by Stor-Ind method, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs/3
Peak Elev= 602.59' @ 13.07 hrs Surf.Area= 0 sf Storage=4,796 cf
( Plug-Flow detention time= 388.1 min calculated for 0.219 af(100% of inflow)
Center-of-Mass det. time= 388.0 min ( 1,140.1 -752.1 )
Volume Invert Avail.Storage Storage Description
#1 598.00' 8,093 cf Custom Stage Data Listed below
Elevation Cum.Store
(feet) (cubic-feet)
598.00 0
599.00 584
600.00 1,582
601.00 2,772
602.00 4,046
603.00 5,321
604.00 6,511
605.00 7,509
606.00 8,093
Device Routing Invert Outlet Devices
#1 Primary 596.50' 15.0" Round Culvert L= 10.6' Ke= 0.500
Inlet/Outlet Invert= 596.50'/596.00' S= 0.0472 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 598.00' 0.100 cfs Constant Flow/Skimmer
#3 Device 1 602.40' 4.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 604.20' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=0.17 cfs @ 13.07 hrs HW=602.59' (Free Discharge)
t-1=Culvert (Passes 0.17 cfs of 13.81 cfs potential flow)
2=Constant Flow/Skimmer (Constant Controls 0.10 cfs)
3=Orifice/Grate (Orifice Controls 0.07 cfs @ 1.48 fps)
-4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)

Herm Project Underground Detention Type 1124-hr 2 yr 24 hr Rainfall=3.92"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 7
Pond 48P: Pape Storage
Hydrograph
4 05 cfs —Inflow II
—Pnmary
4
Inflow Area=0.910 ac
Peak Elev=602.59'
3
Storage=4,796 Cf
✓ 3
E• 2
_ A
018cfs
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)
I

Henn Project Underground Detention Type 1124-hr 10 yr 24 hr Rainfall=4.80"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 8
Summary for Subcatchment 47S: Site
Runoff = 6.28 cfs @ 11.95 hrs, Volume= 0.346 af, Depth= 4.56"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Type II 24-hr 10 yr 24 hr Rainfall=4.80"
Area (ac) CN Description
* 0.910 98
0.910 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry, Tc
Subcatchment 47S: Site
Hydrograph
7- - -
g 28 cfs —Runoff
6- Type 1124-hr
5- 10 yr 24
hr Rainfall=4.80"
4- - Runoff Area=0.910 ac
x Runoff Volume=0.346 af
3- Runoff Depth=4.56"
2- Tc=5.0 min
CN=98
0- r ,,, ,, ., .,, ,, ,, ,,, ,, ,,, , ,,
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)
1

Henri Project Underground Detention Type 1124-hr 10 yr 24 hr Rainfall=4.80"
' Prepared by Microsoft Printed 3/29/2017
HydroCADO 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 9
Summary for Pond 48P: Pipe Storage
Inflow Area = 0.910 ac,100.00% Impervious, Inflow Depth = 4.56" for 10 yr 24 hr event
Inflow = 6.28 cfs @ 11.95 hrs, Volume= 0.346 af
Outflow = 1.09 cfs @ 12.13 hrs, Volume= 0.346 af, Atten= 83%, Lag= 11.0 min
Primary = 1.09 cfs @ 12.1,3 hrs, Volume= 0.346 af
Routing by Stor-Ind method, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs/3
Peak Elev= 604.30' @ 12.13 hrs Surf.Area= 0 sf Storage= 6,811 cf
Plug-Flow detention time= 307.0 min calculated for 0.346 af(100% of inflow)
Center-of-Mass det. time= 308.0 min ( 1,051.7-743.7)
Volume Invert Avail.Storage Storage Description
' #1 598.00' 8,093 cf Custom Stage Data Listed below
Elevation Cum.Store
(feet) (cubic-feet)
598.00 0
599.00 584
600.00 1,582
601.00 2,772
602.00 4,046
603.00 5,321
604.00 6,511
605.00 7,509
606.00 8,093
Device Routing Invert Outlet Devices
#1 Primary 596.50' 15.0" Round Culvert L= 10.6' Ke= 0.500
Inlet/Outlet Invert= 596.50'/596.00' S= 0.0472 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 598.00' 0.100 cfs Constant Flow/Skimmer
#3 Device 1 602.40' 4.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 604.20' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=1.04 cfs @ 12.13 hrs HW=604.30' (Free Discharge)
t-1 Culvert (Passes 1.04 cfs of 15.82 cfs potential flow)
2=Constant Flow/Skimmer (Constant Controls 0.10 cfs)
-3=Orifice/Grate (Orifice Controls 0.55 cfs @ 6.33 fps)
-4=Sharp-Crested Rectangular Weir (Weir Controls 0.39 cfs @ 1.02 fps)

Henn Project Underground Detention Type 11 24-hr 10 yr 24 hr Rainfall=4.80"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 10
Pond 48P: Pipe Storage
Hydrograph
628 cfs - —Inflow
—Primary
Inflow Area=0.910 ac
5 Peak Elegy=60-4.30'
= F Storage=6,811 cf
4-
u
-
0
LL 3-
2 z'
_ a
1 09 cfs I
1-
,—r, ...� �. .moi ,�,-. � .. ,�.. ,. . .. .�.r�T
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)

Herm Project Underground Detention Charlotte 6-hr 50-yr 50 yr 24 hr Rainfall=6.48"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 11
Summary for Subcatchment 47S: Site
Runoff = 9.43 cfs @ 3.10 hrs, Volume= 0.473 af, Depth= 6.24"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 50-yr 50 yr 24 hr Rainfall=6.48"
Area (ac) CN Description
* 0.910 98
0.910 100.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,Tc
Subcatchment 47S: Site
Hydrocrap@1
119 43 cfs - - - —Runoff
9 Charlotte 6-hr
8- 50-yr
7- 50 yr 24 hr Rainfall=6.48"
N 6- Runoff Area=0.910 ac
Runoff Volume=0.473 af
c 5_
= Runoff Depth=6024®e
4.
Tc=5.0 min
3- CN=98
2-
- -
0 5 10 15 20 25 3.0 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)

Henn Project Underground Detention Charlotte 6-hr 50-yr 50 yr 24 hr Rainfall=6.48"
Prepared by Microsoft Printed 3/29/2017
HydroCAD® 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 12
Summary for Pond 48P: Pipe Storage
Inflow Area = 0.910 ac,100.00% Impervious, Inflow Depth = 6.24" for 50 yr 24 hr event
Inflow = 9.43 cfs @ 3.10 hrs, Volume= 0.473 af
Outflow = 9.20 cfs @ 3.12 hrs, Volume= 0.475 af, Atten=2%, Lag= 1.3 min
Primary = 9.20 cfs @ 3.12 hrs, Volume= 0.475 af
Routing by Stor-Ind method, Time Span= 0.00-101.00 hrs, dt= 0.05 hrs/3
Peak Elev= 604.97' @ 3.12 hrs Surf.Area= 0 sf Storage= 7,479 cf
Plug-Flow detention time= 162.6 min calculated for 0.473 af(100% of inflow)
Center-of-Mass det. time= 165.5 min ( 355.5- 190.0 )
Volume Invert Avail.Storage Storage Description
#1 598.00' 8,093 cf Custom Stage Data Listed below
Elevation Cum.Store
(feet) (cubic-feet)
598.00 0
599.00 584
600.00 1,582
601.00 2,772
602.00 4,046
603.00 5,321
604.00 6,511
605.00 7,509
606.00 8,093
Device Routing Invert Outlet Devices
#1 Primary 596.50' 15.0" Round Culvert L= 10.6' Ke= 0.500
Inlet/Outlet Invert= 596.50'/596.00' S= 0.0472 '/' Cc= 0.900
n= 0.012, Flow Area= 1.23 sf
#2 Device 1 598.00' 0.100 cfs Constant Flow/Skimmer
#3 Device 1 602.40' 4.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 604.20' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
Primary OutFlow Max=8.66 cfs @ 3.12 hrs HW=604.93' (Free Discharge)
L1=Culvert (Passes 8.66 cfs of 16.51 cfs potential flow)
-2=Constant Flow/Skimmer (Constant Controls 0.10 cfs)
3=Orifice/Grate (Orifice Controls 0.65 cfs @ 7.41 fps)
-4=Sharp-Crested Rectangular Weir (Weir Controls 7.91 cfs @ 2.80 fps)

Henn Project Underground Detention Charlotte 6-hr 50-yr 50 yr 24 hr Rainfall=6.48II
Prepared by Microsoft Printed 3/29/2017
-_, HydroCADO 10.00 s/n 05047 ©2013 HydroCAD Software Solutions LLC Page 13
Pond 48P: Pipe Storage
Hydrograph
1Qn Iva f —Inflow
920 cfs —Pnmary II
t Inflow Area=0.910 ac
$_ Peak EIev=604.97'
7-
Storage=7,479 cf
6-
N -
C1
c 5- y -
lL
4- -
3-
2-
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Time (hours)
IL
i �,

Determining Number of
as®� Cartridges for Volume-Based
ENGINEERED SOLUTIONS Design in NC
Design Engineer: JDP Blue Cells= Input
Date 3/27/2017 Black Cells= Calculation
Site Information
Project Name Henn Automotive
Project State North Carolina
Project Location Waxhaw
Drainage Area,Ad 0.91 ac
Impervious Area,Ai 0.91 ac
Pervious Area,Ap 0.00
% Impervious 100%
Runoff Coefficient, Rv 0.95 =0.05+0.9*(Al/Ad)
Water Quality Volume Calculations
Design storm rainfall depth,Rd 1.0 in
Water quality volume,WQV 3138.1 ft3 =Ad*Rv*Rd*(43560/12)
Storage Component Calculations
Capture 75%of WQV 2353.6 ft3 =0.75*WQV
Pretreatment credit(estimated or calculated), %pre 30%
Mass loading calculations
Mean Annual Rainfall, P 45 in
Agency required%removal 85%
Percent Runoff Capture(%capture) 90%
Mean Annual Runoff,Vt 127,094 fe =P*Ad*Rv*(43560/12)*%capture
Event Mean Concentration of Pollutant, EMC 70.0 mg/I (Typically 60-Residential/Office,70-Commercial,100-Industrial)
Annual Mass Load, Kota! 555.06 lbs =EMC*Vt*(28.3)*(0.000001)*(2.2046)
Filter System
Filtration brand StormFilter
Cartridge height 27 in
Cartridge Quantity Calculation
Mass removed by pretreatment system, Mpfe 167 lbs =Mtotal*%removal
Mass load to filters after pretreatment,Mpassl 389 lbs =Mtotal-Mpre
Estimate the required filter efficiency, Efilter 79% =1+(%removal-1)/(1 -%pre)
Mass to be captured by filters, Mfilter 305 lbs =Mpassl *Efilter
Maximum Cartridge Flow rate,Qcart 7.5 gpm =q*(7.5 ft2/cartridge)
Mass load per cartridge,M,,a,t(lbs) 54 lbs =lookup mass load per cartridge
Number of Cartridges required,Nmass 6 =ROUNDUP(Mfilter/Mcart,0)
Maximum Treatment Capacity 0.10 =Nmass*(Qcart/449)
SUMMARY
Maximum Treatment Flow Rate,cfs 0.10
Cartridge Flow Rate,gpm 7 5
Number of Cartridges 6
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