Project Infinity BMP ASBUILT Supporting Calculations January 2019

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1 " WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 1
Summary for Subcatchment OS: PRE - DEVELOPMENT
Runoff = 0.29 cfs @ 3.65 hrs, Volume= 0.037 af, Depth= 0.06"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 1-Inch 1" WQ Rainfall=1.25"
Area (ac) CN Description
7.200 73.0 Woods, Fair, HSG C
7.200 100.00% Pervious Area
Tc Length
Slope
Velocity
Capacity Description
(min) (feet)
(ft/ft)
(ft/sec)
(cfs)
12.2 200
0.0335
0.27
Sheet Flow,
Range n= 0.130 P2= 3.32"
13.6 716
0.0310
0.88
Shallow Concentrated Flow,
Woodland Kv= 5.0 fos
25.8 916 Total
Subcatchment OS: PRE - DEVELOPMENT
Hydrograph
— — —I I— T—I — — —
—I— l — —I — —
0.32—I
— _ —
1—
—I — � � — 1—
4
—1 — 4- —1 — 1— -4 — 1— 4 —1 — —
■Runoff
0.3
ors I
1 1 1 1 1 1 1
0.29
0.28
1
1 1
1
1 Charlotte 6-hr 1-Inch
0.26
1 � /nII IC�.
-Ro' IH
0.24
li "ioI
7
0.22
I
I T
I 14
I-k I 1 4 I 4- 1 -4
0.2
-1-
1 —1
_ - - _
1_
_1 _ _1 _ 1_
Runoff
1Valume=9.0 7 af_
018
1
1
11 li 11
Kttl� "'f" h 0,06i1'
0.16
o
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th
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0.12
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_
I_ _I
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1 1
1
1
—1— 1 _I — I— — 1— ON413—
1 1 1 1 1 1'
0.08
0.06
—1-7-1-77—I—T-1-7--1—-1
1 1
1
—1-7-1—F7-
0.04
0.02
1
1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 40 45 160 165 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1 " WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 1S: POST TO SAND FILTER
[49] Hint: Tc<2dt may require smaller dt
Runoff = 13.52 cfs @ 3.12 hrs, Volume= 0.487 af, Depth= 0.54"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 1-Inch 1" WQ Rainfall=1.25"
Area (ac) CN Description
10.770 91.0 Urban industrial, 72% imp, HSG C
3.016 28.00% Pervious Area
7.754 72.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 1S: POST TO SAND FILTER
Hydrograph
15
I. _I_ L _1 _ L
14 13.52
cfs
I I I 1 1
CrlarFofte 6-fir fi-rnchi
13
12
11
-11��111U�(�1�lainf�ll1�56
11
1
_ 1
1
RuAoff Ar6& M.7-7-0 -ati
10
1 1
1 1 1
-
1 1
1
1 1
1
1 1 1 1 1 1 1 1 1 1 1
1Ruirioffl VorunYe�0.4$7 of
9
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- _
_11_
_�_
0 7
-1
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LL
6
—7-1—F7-1—T—I—T
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1 1
1 1 1 1 1 1 1 1+ 1 1 11
--1—F7—FT Cr91-.V
5
1- -4 —
1— 4 —1—
4-
—1— —1—k--4-1——1-4--1—�
4
3
2
1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1" WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 7
Summary for Pond 2P: FOREBAY
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 0.54" for 1" WQ event
Inflow = 13.52 cfs @ 3.12 hrs, Volume= 0.487 of
Outflow = 3.47 cfs @ 3.24 hrs, Volume= 0.487 af, Atten= 74%, Lag= 7.1 min
Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of
Secondary = 3.47 cfs @ 3.24 hrs, Volume= 0.487 of
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 767.27' @ 6.02 hrs Surf.Area= 14,419 sf Storage= 11,526 cf
Plug -Flow detention time= 524.6 min calculated for 0.487 of (100% of inflow)
Center -of -Mass det. time= 525.4 min ( 739.8 - 214.4 )
Volume Invert Avail.Storage Storage Description
#1 766.00' 75,720 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
766.00 1,854 0 0
767.00 13,657 7,756 7,756
768.00 16,496 15,077 22,832
769.00 19,407 17,952 40,784
770.00 22,459 20,933 61,717
770.60 24,218 14,003 75,720
Device Routing Invert Outlet Devices
#1 Primary 765.05' 24.00" Round RCP -Round 24"
L= 36.7' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 765.05' / 764.53' S= 0.0142'/' Cc= 0.900
n= 0.012, Flow Area= 3.14 sf
#2 Device 1 767.29' 24.00" W x 4.00" H Vert. 10 YR. ORIFICE C= 0.600
#3 Device 1 769.86' 48.00" x 48.00" Horiz. TOP OF OUTLET STRUCTURE C= 0.600
Limited to weir flow at low heads
#4 Secondary 765.34' FLOW THROUGH RIPRAP BERM (Q=KIA) X 2.00
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00
Disch. (cfs) 0.000 0.003 0.005 0.008 0.011 0.013
#5 Device 1 769.34' 36.00" W x 6.00" H Vert. 25 YR. ORIFICE C= 0.600
#6 Secondary 765.87' 6.00" Round Culvert X 4.00 L= 28.9' Ke= 0.500
Inlet / Outlet Invert= 765.87' / 765.59' S= 0.0097'/' Cc= 0.900
n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf
Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=766.00' TW=0.00' (Dynamic Tailwater)
L1=RCP_Round 24" (Passes 0.00 cfs of 4.88 cfs potential flow)
2=10 YR. ORIFICE ( Controls 0.00 cfs)
3=TOP OF OUTLET STRUCTURE( Controls 0.00 cfs)
5=25 YR. ORIFICE ( Controls 0.00 cfs)
Secondary OutFlow Max=3.20 cfs @ 3.24 hrs HW=766.96' TW=766.23' (Dynamic Tailwater)
�__:Culvert
FLOW THROUGH RIPRAP BERM (Q=KIA)(Custom Controls 0.01 cfs)
(Outlet Controls 3.19 cfs @ 4.06 fps)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1" WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 8
Pond 2P: FOREBAY
Hydrograph
/ t -1 - - F -t -1 - I- 1- t -1 - F t -i - I- r t -1 - I- t -t -I - I
i I-++LOIlow
13.52cfs tflowInffow Area .770 ac imary15 ' _I t condary
14 ' -1 -1- Peak Elev=767.27'
13 Storage=11,526 cf
12
11 t F I
10 t I- -t-1 1--t 1 I
H 9/ 4� + � 1 � 4 1 �
w
8
_0 7 - - - - - - - - -1- - -
LL
g
3.47 cfs
5 I - - - - - - - - -
4
I I I I I I I I I I I I I I I I I
1
m
d
w
c
0
d
w
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105110 115 120
Time (hours)
Pond 2P: FOREBAY
Stage -Discharge
0 5 10 15 20 25 30 35 40
Discharge (cfs)
❑ Total
❑ Primary
❑ Secondary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1" WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 13
Summary for Pond 3P: SAND FILTER
[78] Warning: Submerged Pond 2P Secondary device # 4 by 1.93'
Inflow = 3.47 cfs @ 3.24 hrs, Volume= 0.487 of
Outflow = 0.21 cfs @ 6.03 hrs, Volume= 0.463 af, Atten= 94%, Lag= 167.8 min
Primary = 0.21 cfs @ 6.03 hrs, Volume= 0.463 of
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 767.27' @ 6.03 hrs Surf.Area= 4,855 sf Storage= 7,704 cf
Plug -Flow detention time= 609.1 min calculated for 0.463 of (95% of inflow)
Center -of -Mass det. time= 527.8 min ( 1,267.5 - 739.8 )
Volume
Invert Avail.Storage Storage
Description
#1
765.34'
24,571 cf SAND FILTER STORAGE (Prismaticyisted below (Recalc)
Elevation
Surf.Area
Inc.Store
Cum.Store
(feet)
(sq-ft)
(cubic -feet)
(cubic -feet)
765.34
3,093
0
0
766.00
3,756
2,260
2,260
767.00
4,610
4,183
6,443
768.00
5,529
5,070
11,513
769.00
6,513
6,021
17,534
770.00
7,561
7,037
24,571
Device Routing Invert Outlet Devices
#1 Primary 765.66' FILTER MEDIA
Head (feet) 0.00 2.50 5.00
Disch. (cfs) 0.000 0.327 0.532
Primary OutFlow Max=0.21 cfs @ 6.03 hrs HW=767.27' TW=0.00' (Dynamic Tailwater)
L1=FILTER MEDIA (Custom Controls 0.21 cfs)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1 " WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 14
3
0
d
0
c
0
d
w
Pond 3P: SAND FILTER
Hydrograph
Time (hours)
Pond 3P: SAND FILTER
Stage -Discharge
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Discharge (cfs)
■ Inflow
❑ Primary
■ Primary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 1-Inch 1 " WQ Rainfall=1.25"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 19
Summary for Pond 4P: TOTAL
[40] Hint: Not Described (Outflow=Inflow)
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 0.52" for 1" WQ event
Inflow = 0.21 cfs @ 6.03 hrs, Volume= 0.463 of
Primary = 0.21 cfs @ 6.03 hrs, Volume= 0.463 af, Atten= 0%, Lag= 0.0 min
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 4P: TOTAL
Hydrograph
+
t
t t
■ Inflow
0.23
i 0.zI cfs 1
T T
T J
T 1
T
1 T 7 I
T J
1- TT T T
Primary
0.21
o.z its
-II
0.21
-1-
I -I - 1-
I -1
_ 1_ 1
_I�1fI�iW_IAre
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0.2
- 1
1
1 1
T
1-4 I
I T� I T
0.19
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t -1 -I-
t -1-
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-1- -t - I
- t -1
-I- t t -I- t -
0.18
T -I-
T J -I-
T
T
- I - T 7 - I
- T J
-I- T T -I- T-
0.17
0.16
_I_
L J -I-
1 -1-
I_ 1
-1- J 1 - I
- L J
-I- 1 J -I- 1-
0.15
A 1
T 1
T
1 4 I
A
I T I T
0.14
-T .-
fi I I
-r I
T
I L rt I
fi I
I t I T
0.13
0.12
T
T
T
c 0.11
L 1
L
-1 1-
1 1
1
1 L 1 I
L -1I
L -1I 1
LL 0.1
4 - I
- 4-
-I-
T -I-
I- T
-I- 4 - I
- -4
-1- T -4 -I- T -
0.09
-T I
r 1
rt
T
L-1 I
t- I
I tI T
0.08
1
I
1
1 1
1 T 1
0.07
- -
- - - -
-
- - -
- - - - -
- - -
- - - - - - - -
0.06
L I
LL I
1
1 L-1 I
L-1
I 1-1 11
0.05
-+ - I
- i- � - I
- +- -
- I- +
-1 - 4 - I
- I
- I- t - I- + -
0.04
T- I
- TT - I
-T
-1- T-1-T-T-I
-I-TT-I-T-
0.03
0.02
0.01
0
0
5 10 15
20 25 30
35 40 45
50 55
60 65
70 75 80 85
90 95
100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 22
Summary for Subcatchment OS: PRE - DEVELOPMENT
Runoff = 8.97 cfs @ 3.46 hrs, Volume= 0.668 af, Depth= 1.11"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Area (ac) CN Description
7.200 73.0 Woods, Fair, HSG C
7.200 100.00% Pervious Area
Tc Length
Slope
Velocity
Capacity Description
(min) (feet)
(ft/ft)
(ft/sec)
(cfs)
12.2 200
0.0335
0.27
Sheet Flow,
Range n= 0.130 P2= 3.32"
13.6 716
0.0310
0.88
Shallow Concentrated Flow,
Woodland Kv= 5.0 fos
25.8 916 Total
Subcatchment OS: PRE - DEVELOPMENT
Hydrograph
10
f'."
cfs91 1 1 1 1 1 1Charrlottel 6ohr 10-yrr
1 1 1 1 1 10 1r ohr R1,ainfall 3.1AA01"
8 1
I II I I I I I I I I Y- I I T �T I
7
1 1 1 1 1 Runbff Ater=7.200 at
I I I I I I I I I I I I I I I I I I I I
6 1 1 1 1Run0ff1 V-0[ume=;Q.668 a#
w 11 `ff 1 D q pr7h 1.111-1 �.
5
q I I I I I I I I I I I I I I I I I I LL
I I I
Tc=25.18 min
3
2
I 1 I L J 1 1 1 L I L 1 L- 1 1 L 1 L
1 I I I I I I I I I I I I I I I I
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 25
Summary for Subcatchment 1S: POST TO SAND FILTER
[49] Hint: Tc<2dt may require smaller dt
Runoff = 51.11 cfs @ 3.15 hrs, Volume= 2.196 af, Depth= 2.45"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Area (ac) CN Description
10.770 91.0 Urban industrial, 72% imp, HSG C
3.016 28.00% Pervious Area
7.754 72.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 1S: POST TO SAND FILTER
Hydrograph
55
50
ii
1 1 1 1 1 1 1 1 1 1 1■Runoff
1 1 1 1 Charrlotte 6hr 10-yrr
45/
fi-1-1�Oyr- I hr, Rainfall-73.;401'
I I I I I I I
40 ,
1 1 ' ' 1 1 Ruhoff Arda:�:10.770 at
35
_I_ I _I I I I I _I_ � _I I
- 1 1 1 1offl Volume-P2.196 of
Ruin
1 - 1
11
30
1 1 1 1 1 1 1 04ff nO'1DaOh72.�451'
R.M 25
l l l l l l
Tc$3 friii h
20
C1 J1.0
I -k 1 1 -4 1 4- 1 � 1 �
15
1 1 1 1
10
F--1-1-7-1—T-1—T-1 —T- —I —F-
I I I
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 29
Primary OutFlow Max=4.69 cfs @ 3.59 hrs HW=769.42' TW=0.00' (Dynamic Tailwater)
L1=RCP_Round 24" (Passes 4.69 cfs of 27.75 cfs potential flow)
P3=TOP
=10 YR. ORIFICE (Orifice Controls 4.49 cfs @ 6.74 fps)
OF OUTLET STRUCTURE( Controls 0.00 cfs)
=25 YR. ORIFICE (Orifice Controls 0.20 cfs @ 0.89 fps)
Secondary OutFlow Max=4.56 cfs @ 3.28 hrs HW=769.13' TW=767.65' (Dynamic Tailwater)
�--6=Cullvert
4=FLOW THROUGH RIPRAP BERM (Q=KIA)(Custom Controls 0.02 cfs)
(Outlet Controls 4.54 cfs @ 5.78 fps)
Pond 2P: FOREBAY
Hydrograph
■Inflow
51.11
cfs
Arep=,1 7
■ouOOutflow
Ia�
■ Secondary aod
55
Ilnflgw,
I Pdak Ele'v::1769142'
50
1 — 1— t —1 — 1— r rt —1 — I— t- rt —I — I— fi
'
_ Storage 49,1144 d
45
40-'
fi
35
N
II III II II
I I I I I I I I I I I I I
w
—"-30-
IIfi-1Ir-rtIIt-rtIIfi
3
25
_
20rt��rt�rtII�
9.07 ors
15 i
I I I I I I I
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hrRainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 30
m
d
w
c
0
d
w
Pond 2P: FOREBAY
Stage -Discharge
0 5 10 15 20 25 30 35 40
Discharge (cfs)
❑ Total
❑ Primary
❑ Secondary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hr Rainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 36
Pond 3P: SAND FILTER
Hydrograph
4.81 cfs I I I I I I I I I
5 1 1 1 1 1 1 Peak E llev=769.19"
-------------------------------
1 1 1 1 1 1 1 1 1 1 1 1
" t rya -'1 gAT g0'3'd
4 T
I I I I I I I I I I I I I I I I I I I I I
( I I I I I I I I I I I I I I I I I I I I I
F 3
c
LL
2
I I I I I I I I I I I I I I I I I I I
I— t —I-
1I I I I I I I I I I I I I I
1
I I I I I I I I I I I I
0 41 cfs_
d
0
c
0
d
w
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Pond 3P: SAND FILTER
Stage -Discharge
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Discharge (cfs)
■ Inflow
❑ Primary
■ Primary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 10-yr 10yr-6hrRainfall=3.40"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 41
Summary for Pond 4P: TOTAL
[40] Hint: Not Described (Outflow=Inflow)
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 2.42" for 10yr-6hr event
Inflow = 5.05 cfs @ 3.60 hrs, Volume= 2.172 of
Primary = 5.05 cfs @ 3.60 hrs, Volume= 2.172 af, Atten= 0%, Lag= 0.0 min
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 4P: TOTAL
Hydrograph
❑ Inflow
❑ Primary
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01 "
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 44
Summary for Subcatchment OS: PRE - DEVELOPMENT
Runoff = 12.47 cfs @ 3.45 hrs, Volume= 0.921 af, Depth= 1.53"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01"
Area (ac) CN Description
7.200 73.0 Woods, Fair, HSG C
7.200 100.00% Pervious Area
Tc Length
Slope
Velocity
Capacity Description
(min) (feet)
(ft/ft)
(ft/sec)
(cfs)
12.2 200
0.0335
0.27
Sheet Flow,
Range n= 0.130 P2= 3.32"
13.6 716
0.0310
0.88
Shallow Concentrated Flow,
Woodland Kv= 5.0 fos
25.8 916 Total
Subcatchment OS: PRE - DEVELOPMENT
Hydrograph
1- - —
1— 4 —1—
4-
i
—1— —1 — -4 — I — —I— —1 —
■Runoff
13 12.47
12
cfs
-1-
-1-
—1—-1�Marrloffel ��hn 25=yrr
11
2L5Yr-hrRainfallz4.101
10
—
— — — — — — — — — —
— — —
— —
— — nbff Ate=T- ND a�
9
I
——+——
I I I I I I I
——�A-1-4-1-4-—iRunoffNotume=4.92-1-a#
I I
I I
II Iw�' I `, I I I I I
-11-
— — — —
11 -�- - -11- 11 -
—
�- 11 -11-
—
—
-�- 11 4f11�ppth 11.1 -3 •
3 7
o
LL 6 ,
1 7 I F 1 F-
1 7
I T
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I r 1 Fldw 1L6n { -9t
5
I_I_L_I_LJ_I_L_I_L_I_L_I_L�_I_L__L_I_L
Tc=25.18 min
4
3.0
1--4—I—
—I-4--1—+-1—
-4—I—+—— 1—•
3
2
1
I- -I —
I— rt —I-
— r —I — r-
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01 "
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 47
Summary for Subcatchment 1S: POST TO SAND FILTER
[49] Hint: Tc<2dt may require smaller dt
Runoff = 61.44 cfs @ 3.15 hrs, Volume= 2.717 af, Depth= 3.03"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01"
Area (ac) CN Description
10.770 91.0 Urban industrial, 72% imp, HSG C
3.016 28.00% Pervious Area
7.754 72.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 1S: POST TO SAND FILTER
Hydrograph
I - I - � -I - � ■Runoff
65 61.44 ds 1 1 L 1 L 1 L- 1 1 1 L 1 L
60 I I I I 1 1 1 Charlotte 6ohr 26mr
--------------------
1 1 11 1 2 Ir-�hr Rainf 1 14.1 11"
55 ' �/ a
45 1 1 1 1 1 11 1 1
`, 1 1 1 11 1 1
IRunoffVohi rne--m2.701-7 af
w 40 _1- -1- -1- �'-nC?'ffllDepth 1 -03',
35
M 30
Tc$-5h i h
--1-4-1-4--1-�-1-�- 1-1-�-1-�
25 1 1 1 1 ' 1 1 ' ' 1 CN=91.0
20
15
10
r—I_F-
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01 "
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 51
Primary OutFlow Max=9.24 cfs @ 3.46 hrs HW=769.90' TW=0.00' (Dynamic Tailwater)
L1=RCP_Round 24" (Passes 9.24 cfs of 29.67 cfs potential flow)
P3=TOP
=10 YR. ORIFICE (Orifice Controls 5.01 cfs @ 7.52 fps)
OF OUTLET STRUCTURE (Weir Controls 0.36 cfs @ 0.62 fps)
=25 YR. ORIFICE (Orifice Controls 3.87 cfs @ 2.58 fps)
Secondary OutFlow Max=4.99 cfs @ 3.28 hrs HW=769.69' TW=767.91' (Dynamic Tailwater)
�--6=Cullvert
4=FLOW THROUGH RIPRAP BERM (Q=KIA)(Custom Controls 0.02 cfs)
(Outlet Controls 4.97 cfs @ 6.33 fps)
Pond 2P: FOREBAY
Hydrograph
T T
I I I I I I I I I I
T T T T 1 T T T
■ Inflow
614 cfs
—I—
t-
t �Q t
-I
outflow
PrimaryInfc�wA-_10.
a
—
■ Secondary
65
_
1_ -1-1-
-1 -1- PdA-E1&::i7-$9190!
60
'
1
1
1 1 1 1 1 1 1 1 1 1 1 1
Storarge=F5,9,423-cf
55
-1 -1- 1- t -1 -
1- fi t -1
- 1- t -1 -1- r t -1 - 1- t rt -1 - 1- t
50
---T�---��--��---��-I-I-T
45
H 40
" 35
`L30
-1-T-4-1-1-
-1- 4-1-1- -4-1-1-4-
25
II
III II II
14.06 cfs
20
c
oa�
I I I I
I I I
I I I I I I I I I I I I I
I I I I I I I
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr25-yr 25yr-6hrRainfall=4.01"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 52
m
d
w
c
0
d
w
Pond 2P: FOREBAY
Stage -Discharge
0 5 10 15 20 25 30 35 40
Discharge (cfs)
❑ Total
❑ Primary
❑ Secondary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01 "
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 58
Pond 3P: SAND FILTER
Hydrograph
I I I I I I I I I I I I I I I I I I
■ Inflow
5 23 cfs 0 Primary
-1 Peak Et16v=-69:43"
5 1 1 1 1 1 1 1 1 1 1 1
_Rtbi`ago=�Q,8615 d
4
- fi� I rt I� rt I fi I I rt I� rt I L� I rt I
N
c I I I I I I I I I I I I I I I I I I I I
LL I I I I I-I-+-1- 4-1--1-I I
I I I I I I I I I I I I I I I
2
1 L-1 1 L-1 I L 1
I I I I I I I I I I I I I
1 I I I I I I I I I I I I I
n 44 cf, I I I I I I I I I I
d
0
c
0
d
w
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Pond 3P: SAND FILTER
Stage -Discharge
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Discharge (cfs)
■ Primary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 25-yr 25yr-6hr Rainfall=4.01 "
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 63
Summary for Pond 4P: TOTAL
[40] Hint: Not Described (Outflow=Inflow)
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 3.00" for 25yr-6hr event
Inflow = 9.61 cfs @ 3.46 hrs, Volume= 2.693 of
Primary = 9.61 cfs @ 3.46 hrs, Volume= 2.693 af, Atten= 0%, Lag= 0.0 min
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 4P: TOTAL
Hydrograph
I
4
I I I
1 1
I I I
1 4 1
I I
I
1
I I I I I I I I I I I I
14 1 1 4 1
■Inflow
9.61ds
I I I I I
10 Primary
9.61
10
ors
-Inf�oArea—ialMac-
-Inflow
g—
— — —
1I I
— — — —
I I I
— — — —
I I
— —
I I
— — — — — — — — — — — — — — — — —
I I I I I I I I I I I I
8
1_1_L_I_1_1_1_L-1_1_1_1_I_-1_1_1-J_I_1_I_LJ
7
I I I
1 1
I I I
1 4-1—{-4
I I
I I
1 +
I I I I I I I I I I I
1 4 —1— --1 1 4 —1-
4 6
I—T
7—I—F-7-1—T
7-1—T-1-1—T-1-1 1
05
a
I_I_I_I_I_I_I
I I I
I I I
_I_I_I_I_I_I_I_I_I_I_I_I
I I
I I
I I I I I I I I I 1 1
4
I L I
1 1 1
L 1
1 1
I A I L- 1 1 1 L 1
3
I I I
—fi—-1—fi—I—t-�—I—t-1——-t—I—t--1—t-1—
I I I
I I
I I
I I I I I I I I I I I
-1
2
I I I
1I
I I I
I I I
I I
I I
I I
I
I I I I I I I I I
—
I I I I I I
1
0 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 66
Summary for Subcatchment OS: PRE - DEVELOPMENT
Runoff = 15.22 cfs @ 3.41 hrs, Volume= 1.128 af, Depth= 1.88"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Area (ac) CN Description
7.200 73.0 Woods, Fair, HSG C
7.200 100.00% Pervious Area
Tc Length
Slope
Velocity
Capacity Description
(min) (feet)
(ft/ft)
(ft/sec)
(cfs)
12.2 200
0.0335
0.27
Sheet Flow,
Range n= 0.130 P2= 3.32"
13.6 716
0.0310
0.88
Shallow Concentrated Flow,
Woodland Kv= 5.0 fos
25.8 916 Total
Subcatchment OS: PRE - DEVELOPMENT
Hydrograph
17--t--t--��--t--t----��--t-I-1
_
_ -1-
I_ -1-
-I-_
-I-�
16 15.22dr
1 - 1 4- 1 L 1
15
1 1
1 L I L-1
1 1
1 L
I L Charlot#eL6ohr 50-yT
14
lir, Rllainfalll=W.481y"
13
40yr=
12
nbff Ateti= -200 s1L
11
I
11 7
I I I I I
1 F-
I I
1 7
I I
1 L
I I I I I I I I � I� Ip I
IRumoffAfolume�'1.i 28-af
a 19
1-
Q-11-
11
1-4-1-4-11-4--1-4-
-741-1-
_0 8
a
1
1 L-1
I 1-I-L-I-L
1 Rdw IL6nt i1=9 �
T
7
I_ 1
g
�II
TCi=25.Iy rn i n
5
1
�
4
T
1 1
1 T I -1
1 7
1
1 L
I I 1 1
1 r 1F -1 1 T IL 1F
3
t
I�1IfiILI�I��
LIB
2
1-�-1-4-1-4--1-4---1—
-4-1 —4--1—�
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
■ Runoff

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 69
Summary for Subcatchment 1S: POST TO SAND FILTER
[49] Hint: Tc<2dt may require smaller dt
Runoff = 69.28 cfs @ 3.10 hrs, Volume= 3.122 af, Depth= 3.48"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Area (ac) CN Description
10.770 91.0 Urban industrial, 72% imp, HSG C
3.016 28.00% Pervious Area
7.754 72.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 1S: POST TO SAND FILTER
Hydrograph
75
■ Runoff
70 69.28 cfs
I I I I
rt fi 1 r- I
I I
rt
I I
I fi
I I I �I w I I I c I I C 1 1
fi ICh �slat#er Vohr-JW�
65
_
�/I - � I-Rlai.�
-50
��r--�r nfall=4.,4'81
60
55
_
_ _ _ _ _ _
_ _ _
_
Ru LVff Arch# 1 0.770 -at
50 1
fi fi 1
fi
t
1 1 1 1 1 1 1 1 1 1
Ru �l/�i1{n e=;3.1CL a
w45
1��1��1�1�1�
n�111C� ��1 In
=40
1_1_
1
1
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`0 35
_1
I I 1 I I 1
_1_
1 I
11
_1_ _----111_�_p_�_�
11 1- 1 1 I Tc�k �19 tWi h
30
I I I I I I
t fi 1
I I
fi
I I
t
I I I I I I I � I+� I�� I I
t —C+ � 71.0
25
1 1-
1 1 - 1 1 4- 1 L
20
15
10
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 72
Summary for Pond 2P: FOREBAY
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 3.48" for 50yr-6hr event
Inflow = 69.28 cfs @ 3.10 hrs, Volume= 3.122 of
Outflow = 23.12 cfs @ 3.31 hrs, Volume= 3.122 af, Atten= 67%, Lag= 12.7 min
Primary = 17.90 cfs @ 3.32 hrs, Volume= 2.290 of
Secondary = 5.47 cfs @ 3.22 hrs, Volume= 0.833 of
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 770.13' @ 3.32 hrs Surf.Area= 22,844 sf Storage= 64,692 cf
Plug -Flow detention time= 214.0 min calculated for 3.121 of (100% of inflow)
Center -of -Mass det. time= 215.1 min ( 416.9 - 201.8 )
Volume Invert Avail.Storage Storage Description
#1 766.00' 75,720 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
766.00 1,854 0 0
767.00 13,657 7,756 7,756
768.00 16,496 15,077 22,832
769.00 19,407 17,952 40,784
770.00 22,459 20,933 61,717
770.60 24,218 14,003 75,720
Device Routing Invert Outlet Devices
#1 Primary 765.05' 24.00" Round RCP -Round 24"
L= 36.7' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 765.05' / 764.53' S= 0.0142'/' Cc= 0.900
n= 0.012, Flow Area= 3.14 sf
#2 Device 1 767.29' 24.00" W x 4.00" H Vert. 10 YR. ORIFICE C= 0.600
#3 Device 1 769.86' 48.00" x 48.00" Horiz. TOP OF OUTLET STRUCTURE C= 0.600
Limited to weir flow at low heads
#4 Secondary 765.34' FLOW THROUGH RIPRAP BERM (Q=KIA) X 2.00
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00
Disch. (cfs) 0.000 0.003 0.005 0.008 0.011 0.013
#5 Device 1 769.34' 36.00" W x 6.00" H Vert. 25 YR. ORIFICE C= 0.600
#6 Secondary 765.87' 6.00" Round Culvert X 4.00 L= 28.9' Ke= 0.500
Inlet / Outlet Invert= 765.87' / 765.59' S= 0.0097'/' Cc= 0.900
n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf
Primary OutFlow Max=17.58 cfs @ 3.32 hrs HW=770.12' TW=0.00' (Dynamic Tailwater)
L1=RCP_Round 24" (Passes 17.58 cfs of 30.53 cfs potential flow)
2=10 YR. ORIFICE (Orifice Controls 5.24 cfs @ 7.86 fps)
3=TOP OF OUTLET STRUCTURE (Weir Controls 7.11 cfs @ 1.68 fps)
5=25 YR. ORIFICE (Orifice Controls 5.23 cfs @ 3.49 fps)
Secondary OutFlow Max=5.23 cfs @ 3.22 hrs HW=769.99' TW=768.05' (Dynamic Tailwater)
�__:Culvert
FLOW THROUGH RIPRAP BERM (Q=KIA)(Custom Controls 0.02 cfs)
(Outlet Controls 5.20 cfs @ 6.62 fps)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 73
w
0
0
U.
m
d
w
c
0
d
w
23.12 cfs
15L10
Pond 2P: FOREBAY
Hydrograph
I —I —I —I I —I —I
—I I—I—i—IJ—I—i
I —I —I —I I —I —I —I
❑ Inflow
r
-
- Inflow Area=10.770
❑ Outflow
❑Primary
ac
❑ Secondary
1 Peak Elev=770.13'
Storage=64,692 cf
t-1
+-11 fi 1 1— �--1 1 1
+� I +— —1—
+ I I—
+� I + 1 I + 4 1 I
4� I -4 1
I �� 1 1
+� I 4 1 I 4 1 —
4� 1 L-L 1
1 1--J 1 1
+� 1 -L 1 1 L-4 1—
L
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105110 115 120
Time (hours)
Pond 2P: FOREBAY
Stage -Discharge
0 5 10 15 20 25 30 35 40
Discharge (cfs)
❑ Total
❑ Primary
❑ Secondary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 78
Summary for Pond 3P: SAND FILTER
[78] Warning: Submerged Pond 2P Secondary device # 4 by 4.26'
[80] Warning: Exceeded Pond 2P by 1.10' @ 8.75 hrs (3.93 cfs 2.531 af)
Inflow = 5.47 cfs @ 3.22 hrs, Volume= 0.833 of
Outflow = 0.44 cfs @ 4.21 hrs, Volume= 0.809 af, Atten= 92%, Lag= 59.0 min
Primary = 0.44 cfs @ 4.21 hrs, Volume= 0.809 of
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 769.60' @ 4.21 hrs Surf.Area= 7,140 sf Storage= 21,619 cf
Plug -Flow detention time= 649.1 min calculated for 0.809 of (97% of inflow)
Center -of -Mass det. time= 582.8 min ( 1,303.8 - 721.0 )
Volume Invert Avail.Storage Storage Description
#1 765.34' 24,571 cf SAND FILTER STORAGE (Prismaticyisted below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
765.34 3,093 0 0
766.00 3,756 2,260 2,260
767.00 4,610 4,183 6,443
768.00 5,529 5,070 11,513
769.00 6,513 6,021 17,534
770.00 7,561 7,037 24,571
Device Routinq Invert Outlet Devices
#1 Primary 765.66' FILTER MEDIA
Head (feet) 0.00 2.50 5.00
Disch. (cfs) 0.000 0.327 0.532
Primary Outflow Max=0.44 cfs @ 4.21 hrs HW=769.60' TW=0.00' (Dynamic Tailwater)
L1=FILTER MEDIA (Custom Controls 0.44 cfs)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 79
Pond 3P: SAND FILTER
Hydrograph
■ Inflow
6 crs D �I .� 14 IC'II� 'J n Primary
I I I I I I I I I I I I I I I I I I I I I I
5 I I I I I I I I I I I �tpea �
I I I I I I I I I I I I I I I I I I I I
4
N
3 3
0
LL
I I I I I I I I I
2
I I I I l i l l l l l l l l
1 I I I I I I I I I I I I
Iff, I I I I I I I I I I
d
0
c
0
d
w
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Pond 3P: SAND FILTER
Stage -Discharge
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Discharge (cfs)
■ Primary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 50-yr 50yr-6hr Rainfall=4.48"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 84
Summary for Pond 4P: TOTAL
[40] Hint: Not Described (Outflow=Inflow)
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 3.45" for 50yr-6hr event
Inflow = 18.24 cfs @ 3.32 hrs, Volume= 3.098 of
Primary = 18.24 cfs @ 3.32 hrs, Volume= 3.098 af, Atten= 0%, Lag= 0.0 min
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 4P: TOTAL
Hydrograph
4 1
1 1
4 1
-4
1 T I
4 1
1 4 1 1
■Inflow
20 18.24 1
t 1 1-+
I-j
I+ 1-f
—I—
I-1'�n� I
❑Primary
19 18.24crs —1
fi 1 1
rt 1
� rt
1 t 1 -Inflow Aroma=101/V�ac
18
—I—
T —I — I—
7 —I—
l- -7
—I— T —I — I—
7 —I—
T -1
— I— T —I— F- 7 —I-
17
16 —
— — — —
— — —
— — —
— — — — —
— — —
— — —
— — — — — — — — —
15 —
— — — —
— — —
— — —
— — — — —
— — —
— — —
— — — — — — — — —
14
13
12
N
1_I_L
v 11 1
1 1
- I
-
I I
- I
L-
I -L I L T
3 10
� 1 1
4 I
-4
I + 1
4 I
A
1 4 1
LL 9 ——
—1-1-4—I—}
-4—I—+-1——
—I—+--1-1—+-1—
�
8——t-1-1—-t
I-1-�—I—t-1——-—I—t--1—t-1—
1
7——
-r —I —I—
-r I-1--—I—T—I——-t
1-71-1—T—I—
--I
6
1r
1 1
71F
-11+
1 1
11r-1171r
I
5
4-
- — —
— — —
— — —
— — — — —
— — —
— — —
— — —
3I-
2
1
0
0 5 10 15
20 25 30
35 40
45 50
55 60 65 70
75 80
85 90
95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 87
Summary for Subcatchment OS: PRE - DEVELOPMENT
Runoff = 18.50 cfs @ 3.40 hrs, Volume= 1.349 af, Depth= 2.25"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Area (ac) CN Description
7.200 73.0 Woods, Fair, HSG C
7.200 100.00% Pervious Area
Tc Length
Slope
Velocity
Capacity Description
(min) (feet)
(ft/ft)
(ft/sec)
(cfs)
12.2 200
0.0335
0.27
Sheet Flow,
Range n= 0.130 P2= 3.32"
13.6 716
0.0310
0.88
Shallow Concentrated Flow,
Woodland Kv= 5.0 fos
25.8 916 Total
Subcatchment OS: PRE - DEVELOPMENT
Hydrograph
20
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Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 90
Summary for Subcatchment 1S: POST TO SAND FILTER
[49] Hint: Tc<2dt may require smaller dt
Runoff = 79.41 cfs @ 3.10 hrs, Volume= 3.539 af, Depth= 3.94"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Area (ac) CN Description
10.770 91.0 Urban industrial, 72% imp, HSG C
3.016 28.00% Pervious Area
7.754 72.00% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 1S: POST TO SAND FILTER
Hydrograph
■Runoff
85
79.41
80
cfs
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0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCAD® 10.00-17 s/n 03513 ©2016 HydroCAD Software Solutions LLC Page 93
Summary for Pond 2P: FOREBAY
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 3.94" for 100yr-6hr event
Inflow = 79.41 cfs @ 3.10 hrs, Volume= 3.539 of
Outflow = 34.58 cfs @ 3.27 hrs, Volume= 3.539 af, Atten= 56%, Lag= 9.8 min
Primary = 29.06 cfs @ 3.27 hrs, Volume= 2.693 of
Secondary = 5.69 cfs @ 3.21 hrs, Volume= 0.846 of
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Peak Elev= 770.34' @ 3.27 hrs Surf.Area= 23,457 sf Storage= 69,528 cf
Plug -Flow detention time=194.1 min calculated for 3.538 of (100% of inflow)
Center -of -Mass det. time= 195.2 min ( 396.3 - 201.1 )
Volume Invert Avail.Storage Storage Description
#1 766.00' 75,720 cf Custom Stage Data (Prismatic)Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic -feet) (cubic -feet)
766.00 1,854 0 0
767.00 13,657 7,756 7,756
768.00 16,496 15,077 22,832
769.00 19,407 17,952 40,784
770.00 22,459 20,933 61,717
770.60 24,218 14,003 75,720
Device Routing Invert Outlet Devices
#1 Primary 765.05' 24.00" Round RCP -Round 24"
L= 36.7' RCP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 765.05' / 764.53' S= 0.0142'/' Cc= 0.900
n= 0.012, Flow Area= 3.14 sf
#2 Device 1 767.29' 24.00" W x 4.00" H Vert. 10 YR. ORIFICE C= 0.600
#3 Device 1 769.86' 48.00" x 48.00" Horiz. TOP OF OUTLET STRUCTURE C= 0.600
Limited to weir flow at low heads
#4 Secondary 765.34' FLOW THROUGH RIPRAP BERM (Q=KIA) X 2.00
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00
Disch. (cfs) 0.000 0.003 0.005 0.008 0.011 0.013
#5 Device 1 769.34' 36.00" W x 6.00" H Vert. 25 YR. ORIFICE C= 0.600
#6 Secondary 765.87' 6.00" Round Culvert X 4.00 L= 28.9' Ke= 0.500
Inlet / Outlet Invert= 765.87' / 765.59' S= 0.0097'/' Cc= 0.900
n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf
Primary OutFlow Max=28.39 cfs @ 3.27 hrs HW=770.33' TW=0.00' (Dynamic Tailwater)
L1=RCP_Round 24" (Passes 28.39 cfs of 31.29 cfs potential flow)
2=10 YR. ORIFICE (Orifice Controls 5.44 cfs @ 8.16 fps)
3=TOP OF OUTLET STRUCTURE (Weir Controls 16.77 cfs @ 2.24 fps)
5=25 YR. ORIFICE (Orifice Controls 6.18 cfs @ 4.12 fps)
Secondary OutFlow Max=5.46 cfs @ 3.21 hrs HW=770.25' TW=768.13' (Dynamic Tailwater)
�__:Culvert
FLOW THROUGH RIPRAP BERM (Q=KIA)(Custom Controls 0.03 cfs)
(Outlet Controls 5.44 cfs @ 6.92 fps)

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 94
i
50
45 34.56 I pis
� 40
LL 35 29.06 cfs
30
25
20
15
10 s Po'f� e
d
d
c
0
d
w
Pond 2P: FOREBAY
Hydrograph
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Time (hours)
Pond 2P: FOREBAY
Stage -Discharge
0 5 10 15 20 25 30 35 40
Discharge (cfs)
LInflow
wrydary
❑ Total
■ Primary
■ Secondary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 100
Pond 3P: SAND FILTER
Hydrograph
■Inflow
5 69 cfs 0 Primary
I I
Peak ElIevr� 769.67"
I I I I I I I I I I
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4
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F I I T I I I I
0 3
LL
I I I I I I I I I I I I I I I I I I I
2 l l l l l l l
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1 I I I I I I I I I I I I I
0.45 cfs /%�..
d
0
c
0
d
w
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)
Pond 3P: SAND FILTER
Stage -Discharge
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
Discharge (cfs)
■ Primary

Infinity Sand Filter As Built Jan 2019 Charlotte 6-hr 100-yr 100yr-6hr Rainfall=4.96"
Prepared by Burton Engineering Printed 1/24/2019
HydroCADO 10.00-17 s/n 03513 © 2016 HydroCAD Software Solutions LLC Page 105
Summary for Pond 4P: TOTAL
[40] Hint: Not Described (Outflow=Inflow)
Inflow Area = 10.770 ac, 72.00% Impervious, Inflow Depth = 3.92" for 100yr-6hr event
Inflow = 29.41 cfs @ 3.27 hrs, Volume= 3.515 of
Primary = 29.41 cfs @ 3.27 hrs, Volume= 3.515 af, Atten= 0%, Lag= 0.0 min
Routing by Dyn-Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.05 hrs
Pond 4P: TOTAL
Hydrograph
1
I L
I
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1
1 7 I L-1 1 1 L 1
■ Inflow
29.4
❑Primar
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5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120
Time (hours)