SW3221001_Design Calculations_20230929

STORM CALCULATIONS
FOR
BRIGHTON PARK
MOUNT PLEASANT, CABARRUS COUNTY, NC
PREPARED BY:
LATHAM-WALTERS ENGINEERING, INC.
16507-A NORTHCROSS DRIVE
HUNTERSVILLE, N.C. 28078
Phone: [phone] Fax: [phone]
N.C. Corporate License C-1815
FOR
NIBLOCK HOMES,LLC
759 CONCORD PARKWAY NORTH SUITE 20
CONCORD,NC 28027
DATE: August 4, 2022
Quo oti-%
5 56
MO.
=,°° FNGINO-°°° ,
S L. \\\
REVISED: 2/9/2023
REVISED: 9/11/2023
REVISED: 9/26/2023

Carlos L. Ruano P.E.
Latham-Walters Engineer, Inc.
16507-A Northcross Drive
Huntersville, NC 28078
Brighton Park Stormwater System Design Summary
Stormwater system was designed in accordance with the latest version of the NCDOT's
Guidelines for Drainage Studies& Hydraulic Design, NCDOT Subdivision Manual, & Concord's Technical
Standards Manual.
Roadway inlet locations, capacities,gutter spread, and storm drain pipe system was analyzed
and designed using a ten-year discharge (Q10)with a minimum time of concentration of 5 minutes.An
intensity of 4 inches/hour was used for calculating spread and determination of appropriate locations
for inlet placement.Allowable gutter spread is limited to gutter width plus%travel lane (total of 7 feet
with valley gutter) per the latest version of the NCDOT Subdivision Manual. Per Concord UDO, may flow
may spread to crown of street for Local &Alley.
Concord's Rainfall Intensity Table 2-2 was utilized for hydraulic analysis. Coefficient of 0.50 was
determined by the average BUA per lot. Intensity storm of 7.26 in/hr was used for 10-year return period.
Storm pipes were design by Rational method.
Sediment basins&erosion control measures were based off NCDEQ's Erosion &Sediment
Control Planning& Design Manual.

SECTION 2
STORMWATER RUNOFF
20
10 -
8 -
-
0
r 46 Ref40,A
C 2 7o yeas
>+ s°
th a
a) 1 -
0.8 -
0.6 -(75
• 0.4 -
co
ci
02 -
I
0.1 I P , I I I , I ,
0.1 0.2 0.4 0.6 0.8 1 2 4 6 8 10 20
Duration-Hours
Figure 2-2 Intensity-Duration-Frequency Curves for Concord,NC
TABLE 2-3
ORDINATES OF THE IDF CURVES FOR CONCORD,NC
Duration Return Period (years)
Hours Minute 1 2 5 10 25 50 100
s
0 5 4.80 5.66 6.60 7.26 8.00 8.52 8.98
10 3.83 4.54 5.29 5.81 6.38 6.78 7.13
15 3.19 3.80 4.46 4.90 5.39 5.72 6.01 _
30 2.19 2.62 3.17 3.55 3.99 4.31 4.60
1 1.36 1.65 2.03 2.31 2.66 2.92 3.17
2 0.79 0.96 1.19 1.36 1.58 1.75 1.92
3 0.56 0.68 0.85 0.98 1.15 1.29 1.42
6 0.34 0.41 0.51 0.59 0.70 0.79 0.87
12 0.20 0.24 0.31 0.35 0.42 0.48 0.53
24 0.12 0.14 0.18 0.21 0.25 0.28 0.31
Adopted January 10, 2008 2-5 Technical Standards Manual

PRE-DEVELOPMENT ANALYSIS OFF HWY-73
INC-HWY 73
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' - - EXIST. STORM
POI#2 - PRE

Hydraflow Storm Sewers Extension for Autodesk® AutoCAD® Civil 3D® Plan
EX.DI-1
EX.DA-1 4
POI#1 EX.DI-2
PRE-DEVELOPMENT
3
EX.DI-3
2
EX.DI-4 1
OutfE
POI#2
PRE-DEVELOPMENT
Project File: 2020.17-EX.STORM Hwy73.stm Number of lines:5 Date:9/15/2023
Storm Sewers v2018.30

TR55 Tc Worksheet EX.DA-1
Hydraflow Storm Sewers Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc.v2018.30
Line No. 3
None
Description
A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.12 0.00 0.00
Land slope (%) = 4.30 0.00 0.00
Travel Time (min) = 10.64 + 0.00 + 0.00 = 10.64
Shallow Concentrated Flow
Flow length (ft) = 1117.00 0.00 0.00
Watercourse slope (%) = 3.68 0.00 0.00
Surface description = UnPaved Paved Paved
Average velocity (ft/s) =3.10 0.00 0.00
Travel Time (min) = 6.01 + 0.00 + 0.00 = 6.01
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc 16.66 min

TR55 Tc Worksheet EX.DI-1
Hydraflow Storm Sewers Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc.v2018.30
Line No. 4
4
Description
A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.12 0.00 0.00
Land slope (%) = 5.86 0.00 0.00
Travel Time (min) = 9.40 + 0.00 + 0.00 = 9.40
Shallow Concentrated Flow
Flow length (ft) = 629.00 0.00 0.00
Watercourse slope (%) = 4.82 0.00 0.00
Surface description = UnPaved Paved Paved
Average velocity (ft/s) =3.54 0.00 0.00
Travel Time (min) = 2.96 + 0.00 + 0.00 = 2.96
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc 12.36 min

TR55 Tc Worksheet EX.DI-3
Hydraflow Storm Sewers Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc.v2018.30
Line No. 2
3(2)
Description
A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 100.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.12 0.00 0.00
Land slope (%) = 2.00 0.00 0.00
Travel Time (min) = 14.45 + 0.00 + 0.00 = 14.45
Shallow Concentrated Flow
Flow length (ft) = 700.00 0.00 0.00
Watercourse slope (%) = 7.60 0.00 0.00
Surface description = UnPaved Paved Paved
Average velocity (ft/s) =4.45 0.00 0.00
Travel Time (min) = 2.62 + 0.00 + 0.00 = 2.62
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter(ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00 0.00 0.00
Flow length (ft) = 0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc 17.07 min

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 606.64 0.41 11.13 0.50 7.24 4.91 27.30 602.04 600.98 59.47 30 59.164 1.79 11.85 3 1.19 1.78"" 2.10
2 EX.DI-3 611.12 2.67 10.72 0.50 4.93 4.93 26.44 604.82 602.14 72.30 30 101.210 2.65 7.54 3(2) 1.68 1.75** 3.80
3 EX.DI-2 622.95 0.33 8.05 0.50 7.24 5.61 22.56 614.15 605.72 46.25 24 236.650 3.56 14.62 3(2) 0.99 1.69"" 6.80
4 EX.DI-1 625.15 7.72 7.72 0.50 5.61 5.61 21.67 621.97 616.05 86.05 24 48.000 12.33 22.79 4 0.68 1.66** 1.18
5 EX.DA-1 0.00 6.29 6.29 0.50 4.99 4.99 15.68 •E.mt4 ■ -2.5®■ 19.87 30 28.443 0.20 4.50 I •lief■ 1.67 n/a
A
_FOR CALCULATION
PURPOSES
Project File: 2020.17-EX.STORM Hwy73.stm Number of lines:5 Date: 9/15/2023
NOTES: Intensity=88.24/(Inlet time+ 15.50)A 0.83--Return period= 10 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 606.64 0.41 11.13 0.50 8.25 5.69 31.66 602.04 600.98 59.47 30 59.164 1.79 12.30 3 1.30 1.92"" 2.10
2 EX.DI-3 611.12 2.67 10.72 0.50 5.72 5.72 30.65 604.82 602.14 72.30 30 101.210 2.65 8.03 3(2) 1.82 1.89** 3.80
3 EX.DI-2 622.95 0.33 8.05 0.50 8.25 6.47 26.03 614.15 605.72 46.25 24 236.650 3.56 15.15 3(2) 1.07 1.79"" 6.80
4 EX.DI-1 625.15 7.72 7.72 0.50 6.48 6.48 24.99 621.97 616.05 86.05 24 48.000 12.33 23.73 4 0.74 1.76** 1.18
5 EX.DA-1 0.00 6.29 6.29 0.50 5.78 5.78 18.17 •-2.49. -2.5U • 1 89 30 28.411131 • UD.!a • 6.!10 • ■ • • sl.67m r 1.71 n/a
A
_FOR CALCULATION 1
PURPOSES
Project File: 2020.17-EX.STORM Hwy73.stm Number of lines:5 Date: 9/15/2023
NOTES: Intensity= 102.61 /(Inlet time+ 16.50)^0.82--Return period=25 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 606.64 0.41 11.13 0.50 9.04 6.30 35.07 602.04 600.98 59.47 30 59.164 1.79 12.61 3 1.38 2.01"" 2.10
2 EX.DI-3 611.12 2.67 10.72 0.50 6.33 6.33 33.94 604.82 602.14 72.30 30 101.210 2.65 8.44 3(2) 1.91 1.98** 3.80
3 EX.DI-2 622.95 0.33 8.05 0.50 9.04 7.14 28.74 614.15 605.72 46.25 24 236.650 3.56 15.51 3(2) 1.14 1.84"" 6.80
4 EX.DI-1 625.15 7.72 7.72 0.50 7.15 7.15 27.60 621.97 616.05 86.05 24 48.000 12.33 24.37 4 0.78 1.82** 1.18
5 EX.DA-1 0.00 6.29 6.29 0.50 6.40 6.40 20.11 r2,44 -2.50. 19.87 30 28.443• ■ O.I ■ 16.47 1.67 1.76 n/a
A
-FOR CALCULATION
PURPOSES
Project File: 2020.17-EX.STORM Hwy73.stm Number of lines:5 Date: 9/15/2023
NOTES: Intensity= 114.82/(Inlet time+ 17.20)^0.82--Return period=50 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 606.64 0.41 11.13 0.50 9.83 6.91 38.47 602.04 600.98 59.47 30 59.164 1.79 12.88 3 1.46 2.09"" 2.10
2 EX.DI-3 611.12 2.67 10.72 0.50 6.94 6.94 37.22 604.82 602.14 72.30 30 101.210 2.65 8.87 3(2) 1.99 2.06** 3.80
3 EX.DI-2 622.95 0.33 8.05 0.50 9.83 7.81 31.44 614.15 605.72 46.25 24 236.650 3.56 15.82 3(2) 1.21 1.88"" 6.80
4 EX.DI-1 625.15 7.72 7.72 0.50 7.82 7.82 30.19 621.97 616.05 86.05 24 48.000 12.33 24.96 4 0.82 1.86** 1.18
5 EX.DA-1 0.00 6.29 6.29 0.50 7.01 7.01 22.05 t2•444 -2.50■ 19.87 30 ■ 1281443 *II ■ 6.63s • 1.67 1.82 n/a
A
_FOR CALCULATION 1
PURPOSES
Project File: 2020.17-EX.STORM Hwy73.stm Number of lines:5 Date: 9/15/2023
NOTES: Intensity= 127.16/(Inlet time+17.80)^0.82--Return period= 100 Yrs. ; ""Critical depth
Storm Sewers

POST DEVELOPMENT ANALYSIS OFF HWY-73
0 ‘
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r OQ �0 � u_R m® O ® Q 0
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- 21*00
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55
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BRENNAN STREET
70'PUBLIC!VW

Hydraflow Storm Sewers Extension for Autodesk® AutoCAD® Civil 3D® Plan
5 SDMH-2
6 CB-2
7 8 DGI-4
CB-3
BRENNAN
ENTRANCE
DGI-8
3
DI-5
2
OLEANDER
ENTRANCE EX.DI-2
1
4
Out
4
Riser-2
SEE WQ CALCS
Project File: 2020.17-Prop.STORM Hwy73.stm Number of lines:8 Date:2/9/2023
Storm Sewers v2018.30

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 614.08 0.41 3.16 0.50 7.26 6.64 13.62 602.04 600.98 40.55 30 127.240 0.83 7.45 3 1.00 1.24"" 9.54
2 EX.DI-3 617.04 1.18 2.75 0.50 7.26 6.73 12.38 604.82 602.14 72.30 30 101.210 2.65 5.68 3(2) 1.14 1.18** 9.72
3 EX.DI-2 622.95 0.38 1.57 0.50 7.26 6.87 8.53 614.15 605.72 46.25 24 236.650 3.56 11.22 3(2) 0.58 1.04"" 6.80
4 DI-5 627.92 0.57 1.18 0.50 7.26 6.96 4.53 620.99 616.05 21.76 18 135.000 3.66 9.72 4 0.46 0.82** 5.43
5 DGI-8 635.53 0.61 0.61 0.60 7.26 7.26 2.66 632.00 621.24 24.61 18 229.890 4.68 4.35 0.57 0.62"" 2.03
6 Riser-2 638.00 0.01 0.01 0.01 7.26 7.26 2.75 630.39 617.77 35.98 18 126.170 10.00 12.01 0.28 0.63"" 6.11
7 SDMH-2 631.55 0.01 1.39 0.01 7.26 7.10 4.90 627.09 627.00 8.04 18 18.000 0.50 4.77 0.85 0.85** 2.96
8 CB-2 632.87 0.21 1.38 0.50 7.26 7.13 4.92 627.42 627.29 8.20 18 25.000 0.52 4.85 0.84 0.85"" 3.95
9 CB-3 632.87 0.11 1.17 0.50 7.26 7.18 4.20 627.80 627.62 8.04 18 36.000 0.50 4.60 0.77 0.78** 3.57
10 DGI-4 631.00 1.06 1.06 0.50 7.26 7.26 3.85 628.33 628.00 7.99 18 67.000 0.49 4.48 0.73 0.75"" 1.17
11 VCD-1 0.00 2.68 2.68 0.50 7.26 7.26 9.73 01,78 •200■ ■17.331 • ■2a■ ■141J8F40 •0.90■ ■M80• • T.33• 1.!1•"• n/a
T
FOR CALCULATION
PURPOSES
Project File: 2020.17-Prop.STORM Hwy73.stm Number of lines: 11 Date: 9/15/2023
NOTES: Intensity=71.97/(Inlet time+ 12.40)A 0.80--Return period= 10 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 614.08 0.41 3.16 0.50 7.99 7.37 22.39 602.04 600.98 40.55 30 127.240 0.83 4.91 3 2.19 1.61"" 9.54
2 EX.DI-3 617.04 1.18 2.75 0.50 7.99 7.45 21.00 604.82 602.14 72.30 30 101.210 2.65 6.78 3(2) 1.51 1.56** 9.72
3 EX.DI-2 622.95 0.38 1.57 0.50 7.99 7.57 16.71 614.15 605.72 46.25 24 236.650 3.56 13.52 3(2) 0.83 1.47"" 6.80
4 DI-5 627.92 0.57 1.18 0.50 7.99 7.67 4.99 620.99 616.05 21.76 18 135.000 3.66 9.99 4 0.49 0.86** 5.43
5 DGI-8 635.53 0.61 0.61 0.60 7.99 7.99 2.93 632.00 621.24 24.61 18 229.890 4.68 4.35 0.61 0.65"" 2.03
6 Riser-2 638.00 0.01 0.01 0.01 7.99 7.99 10.34 630.39 617.77 35.98 18 126.170 10.00 17.57 0.55 1.24"" 6.11
7 SDMH-2 631.55 0.01 1.39 0.01 7.99 7.83 5.40 627.09 627.00 8.04 18 18.000 0.50 4.58 0.95 0.90** 2.96
8 CB-2 632.87 0.21 1.38 0.50 7.99 7.86 5.42 627.42 627.29 8.20 18 25.000 0.52 4.70 0.93 0.90"" 3.95
9 CB-3 632.87 0.11 1.17 0.50 7.99 7.90 4.62 627.80 627.62 8.04 18 36.000 0.50 4.71 0.82 0.83** 3.57
10 DGI-4 631.00 1.06 1.06 0.50 7.99 7.99 4.24 628.33 628.00 7.99 18 67.000 0.49 4.58 0.78 0.79"" 1.17
11 VCD-1 0.00 2.68 2.68 0.50 7.99 7.99 10.71 a1_7$ •4.Q1O• • j7.3j • • i4m • •I49i4 • 1.10. ■ i.39• . + 111.l3* 1.17"" n/a
T
FOR CALCULATION
PURPOSES
Project File: 2020.17-Prop.STORM Hwy73.stm Number of lines: 11 Date: 9/15/2023
NOTES: Intensity=61.92/(Inlet time+ 11.00)A 0.74--Return period=25 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 614.08 0.41 3.16 0.50 8.51 7.90 37.10 602.04 600.98 40.55 30 127.240 0.83 8.14 3 2.19 2.06"" 9.54
2 EX.DI-3 617.04 1.18 2.75 0.50 8.51 7.97 35.57 604.82 602.14 72.30 30 101.210 2.65 8.61 3(2) 1.96 2.02** 9.72
3 EX.DI-2 622.95 0.38 1.57 0.50 8.51 8.07 30.96 614.15 605.72 46.25 24 236.650 3.56 15.77 3(2) 1.20 1.88"" 6.80
4 DI-5 627.92 0.57 1.18 0.50 8.51 8.17 5.32 620.99 616.05 21.76 18 135.000 3.66 10.17 4 0.51 0.89** 5.43
5 DGI-8 635.53 0.61 0.61 0.60 8.51 8.51 3.12 632.00 621.24 24.61 18 229.890 4.68 4.35 0.64 0.67"" 2.03
6 Riser-2 638.00 0.01 0.01 0.01 8.51 8.51 24.17 630.39 617.77 35.98 18 126.170 10.00 21.83 0.90 1.48"" 6.11
7 SDMH-2 631.55 0.01 1.39 0.01 8.51 8.33 5.75 627.09 627.00 8.04 18 18.000 0.50 4.87 0.95 0.93** 2.96
8 CB-2 632.87 0.21 1.38 0.50 8.51 8.37 5.77 627.42 627.29 8.20 18 25.000 0.52 4.75 0.98 0.93"" 3.95
9 CB-3 632.87 0.11 1.17 0.50 8.51 8.42 4.93 627.80 627.62 8.04 18 36.000 0.50 3.54 1.10 0.85** 3.57
10 DGI-4 631.00 1.06 1.06 0.50 8.51 8.51 4.51 628.33 628.00 7.99 18 67.000 0.49 4.66 0.81 0.81"" 1.17
11 VCD-1 0.00 2.68 2.68 0.50 8.51 8.51 11.41 •T7115 • •-.SO• • I733 241 ■ 44.98! ■ MACE ■ 6.a3• ■ ■ ■ ■ ■ ■ ■ N.i3+ ■1i24"l` n/a
T
FOR CALCULATION
PURPOSES
Project File: 2020.17-Prop.STORM Hwy73.stm Number of lines: 11 Date: 9/15/2023
NOTES: Intensity=56.49/(Inlet time+ 10.10)A 0.70--Return period=50 Yrs. ; ""Critical depth
Storm Sewers

Dschedule Page
Line Inlet Gnd/Rim Drng Total Runoff i i Flow Invert Invert Capac Line Line Line Vel Line Depth Depth Cover
No. ID El Up Area Area Coeff Inlet Sys Rate Up Dn Full Size Length Slope Dn ID Dn Up Up
(ft) (ac) (ac) (C) (in/hr) (in/hr) (cfs) (ft) (ft) (cfs) (in) (ft) (%) (ft/s) (ft) (ft) (ft)
1 EX.DI-4 614.08 0.41 3.16 0.50 8.98 8.33 43.28 602.04 600.98 40.55 30 127.240 0.83 9.48 3 2.19 2.29 9.54
2 EX.DI-3 617.04 1.18 2.75 0.50 8.98 8.40 41.67 604.82 602.14 72.30 30 101.210 2.65 8.49 3(2) 2.50 2.16** 9.72
3 EX.DI-2 622.95 0.38 1.57 0.50 8.98 8.51 32.06 614.15 605.72 46.25 24 236.650 3.56 15.34 3(2) 1.26 1.89"" 6.80
4 DI-5 627.92 0.57 1.18 0.50 8.98 8.62 5.61 620.99 616.05 21.76 18 135.000 3.66 10.32 4 0.52 0.91** 5.43
5 DGI-8 635.53 0.61 0.61 0.60 8.98 8.98 3.29 632.00 621.24 24.61 18 229.890 4.68 4.36 0.66 0.69"" 2.03
6 Riser-2 638.00 0.01 0.01 0.01 8.98 8.98 24.90 630.39 617.77 35.98 18 126.170 10.00 21.98 0.92 1.49"" 6.11
7 SDMH-2 631.55 0.01 1.39 0.01 8.98 8.77 6.06 627.09 627.00 8.04 18 18.000 0.50 5.13 0.95 0.98 2.96
8 CB-2 632.87 0.21 1.38 0.50 8.98 8.81 6.08 627.42 627.29 8.20 18 25.000 0.52 4.74 1.02 0.96"" 3.95
9 CB-3 632.87 0.11 1.17 0.50 8.98 8.87 5.19 627.80 627.62 8.04 18 36.000 0.50 3.59 1.14 1.00 3.57
10 DGI-4 631.00 1.06 1.06 0.50 8.98 8.98 4.76 628.33 628.00 7.99 18 67.000 0.49 3.94 0.97 0.84"" 1.17
11 VCD-1 0.00 2.68 2.68 0.50 8.98 8.98 12.03 .-y.fi• • •2I4 • ili.13■ • NU • •4t.fi8ii • ■050 ■ m5r1D4 1.23 1.25** n/a
T
FOR CALCULATION
PURPOSES
Project File: 2020.17-Prop.STORM Hwy73.stm Number of lines: 11 Date: 9/15/2023
NOTES: Intensity=50.24/(Inlet time+9.00)A 0.65--Return period= 100 Yrs. ; ""Critical depth
Storm Sewers

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Monday, Sep 11 2023
CB-2 DA: 0.21ac I: 4.0in/hr C: 0.6
Combination Inlet Calculations
Location = On grade Compute by: Known Q
Curb Length (ft) = 3.00 Q (cfs) = 0.50
Throat Height (in) = 5.00
Grate Area (sgft) = -0- Highlighted
Grate Width (ft) = 2.00 Q Total (cfs) = 0.50
Grate Length (ft) = 3.00 Q Capt (cfs) = 0.46
Q Bypass (cfs) = 0.04
Gutter Depth at Inlet (in) = 2.23
Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 92
Slope, Sx (ft/ft) = 0.042 Gutter Spread (ft) = 3.48
Local Depr (in) = 1.00 Gutter Vel (ft/s) = 2.38
Gutter Width (ft) = 2.00 Bypass Spread (ft) = 1.92
Gutter Slope (%) = 1.00 Bypass Depth (in) = 0.46
Gutter n-value = 0.011
All dimensions in feet
2.0 1.48 �—
1

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Monday, Sep 11 2023
CB-3 DA: 0.11ac I: 4.0in/hr C: 0.6
Combination Inlet Calculations
Location = On grade Compute by: Known Q
Curb Length (ft) = 3.00 Q (cfs) = 0.26
Throat Height (in) = 5.00
Grate Area (sgft) = -0- Highlighted
Grate Width (ft) = 2.00 Q Total (cfs) = 0.26
Grate Length (ft) = 3.00 Q Capt (cfs) = 0.25
Q Bypass (cfs) = 0.01
Gutter Depth at Inlet (in) = 1.93
Slope, Sw (ft/ft) = 0.020 Efficiency (%) = 96
Slope, Sx (ft/ft) = 0.042 Gutter Spread (ft) = 2.90
Local Depr (in) = 1.00 Gutter Vel (ft/s) = 1.96
Gutter Width (ft) = 2.00 Bypass Spread (ft) = 1.10
Gutter Slope (%) = 1.00 Bypass Depth (in) = 0.26
Gutter n-value = 0.011
All dimensions in feet
01
0.16
2.0 0.9
l

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
DGI-4 DA: 1.06ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 2.12
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 2.12
Grate Length (ft) = 2.00 Q Capt (cfs) = 2.12
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 1.81
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 5.01
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
All dimensions in feet
0.15
• • • •
0.50 4.00 •
0.50

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
DGI-5 DA: 0.57ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 1.14
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 1.14
Grate Length (ft) = 2.00 Q Capt (cfs) = 1.14
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 1.20
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 4.67
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
All dimensions in feet
-------------
• • • •
0.33 4.00 0.33

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
DGI-8 DA: 0.61 ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 1.22
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 1.22
Grate Length (ft) = 2.00 Q Capt (cfs) = 1.22
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 1.26
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 4.70
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
All dimensions in feet
0.1
• • •
0.35 4.00 0.35

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
EX. DGI-2 DA: 0.38ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 0.76
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 0.76
Grate Length (ft) = 2.00 Q Capt (cfs) = 0.76
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 0.92
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 4.51
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
All dimensions in feet
-------------
• 1{
• •
0.25 4.00 0.25

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
EX.DGI-3 DA:1.18ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 2.36
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 2.36
Grate Length (ft) = 2.00 Q Capt (cfs) = 2.36
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 1.95
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 5.08
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
=.II dimensions in feet
0.54 4.00 0.54

Inlet Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Friday,Sep 15 2023
EX.DGI-4 DA:0.41ac C:0.5 I:4.0in/hr
Drop Grate Inlet Calculations
Location = Sag Compute by: Known Q
Curb Length (ft) = -0- Q (cfs) = 0.82
Throat Height (in) = -0-
Grate Area (sgft) = 4.51 Highlighted
Grate Width (ft) = 4.00 Q Total (cfs) = 0.82
Grate Length (ft) = 2.00 Q Capt (cfs) = 0.82
Q Bypass (cfs) = -0-
Gutter Depth at Inlet (in) = 0.96
Slope, Sw (ft/ft) = 0.300 Efficiency (%) = 100
Slope, Sx (ft/ft) = 0.300 Gutter Spread (ft) = 4.54
Local Depr (in) = -0- Gutter Vel (ft/s) = -0-
Gutter Width (ft) = 4.00 Bypass Spread (ft) = -0-
Gutter Slope (%) = -0- Bypass Depth (in) = -0-
Gutter n-value = -0-
.III dimensions in feet
0.27 4.00 27

Channel Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Sep 26 2023
VCD-1 DA:2.68ac C:0.6 I:7.26in/hr
Trapezoidal Highlighted
Bottom Width (ft) = 2.00 Depth (ft) = 0.79
Side Slopes (z:1) = 3.00, 2.00 Q (cfs) = 11.67
Total Depth (ft) = 2.00 Area (sqft) = 3.14
Invert Elev (ft) = 600.00 Velocity (ft/s) = 3.72
Slope (%) = 2.00 Wetted Perim (ft) = 6.26
N-Value = 0.035 Crit Depth, Yc (ft) = 0.75
Top Width (ft) = 5.95
Calculations EGL (ft) = 1.00
Compute by: Known Q
Known Q (cfs) = 11.67
Elev (ft) Section Depth (ft)
603.00 3.00
602.50 2.50
602.00 2.00
601.50 1.50
601.00 1.00
v
600.50 0.50
600.00 0.00
599.50 -0.50
0 2 4 6 8 10 12 14 16
Reach (ft)

741 NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
>>>VCD-1
Name VCD-1
Discharge 11.67
Channel Slope 0.02
Channel Bottom Width 2
Left Side Slope 3
Right Side Slope 2
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Good 65-79%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 11.67 cfs 3.77 ft/s 0.78 ft 0.035 1.6 Ibs/ft2 0.98 Ibs/ft2 1.64 STABLE D
Underlying Straight 11.67 cfs 3.77 ft/s 0.78 ft 0.035 1.74 Ibs/ft2 0.62 Ibs/ft2 2.81 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 11.67 cfs 3.77 ft/s 0.78 ft 0.035 4 Ibs/ft2 0.98 lbs/ft2 4.1 STABLE --
Vegetation
Underlying Straight 11.67 cfs 3.77 ft/s 0.78 ft 0.035 2.3 Ibs/ft2 0.62 lbs/ft2 3.7 STABLE --
Substrate

Channel Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Sep 26 2023
VCD-2 DA:1.06ac C:0.6 I:7.26in/hr
Trapezoidal Highlighted
Bottom Width (ft) = 2.00 Depth (ft) = 0.49
Side Slopes (z:1) = 3.00, 2.00 Q (cfs) = 4.620
Total Depth (ft) = 2.00 Area (sqft) = 1.58
Invert Elev (ft) = 600.00 Velocity (ft/s) = 2.92
Slope (%) = 2.00 Wetted Perim (ft) = 4.65
N-Value = 0.035 Crit Depth, Yc (ft) = 0.46
Top Width (ft) = 4.45
Calculations EGL (ft) = 0.62
Compute by: Known Q
Known Q (cfs) = 4.62
Elev (ft) Section Depth (ft)
603.00 3.00
602.50 2.50
602.00 2.00
601.50 1.50
601.00 1.00
600.50 0.50
600.00 0.00
599.50 -0.50
0 2 4 6 8 10 12 14 16
Reach (ft)

741 NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> >VCD-2
Name VCD-2
Discharge 4.62
Channel Slope 0.02
Channel Bottom Width 2
Left Side Slope 3
Right Side Slope 2
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Good 65-79%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 4.62 cfs 2.93 ft/s 0.49 ft 0.035 1.6 Ibs/ft2 0.61 Ibs/ft2 2.62 STABLE D
Underlying Straight 4.62 cfs 2.93 ft/s 0.49 ft 0.035 1.74 Ibs/ft2 0.42 lbs/ft2 4.11 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 4.62 cfs 2.93 ft/s 0.49 ft 0.035 4 Ibs/ft2 0.61 lbs/ft2 6.54 STABLE --
Vegetation
Underlying Straight 4.62 cfs 2.93 ft/s 0.49 ft 0.035 2.3 Ibs/ft2 0.42 lbs/ft2 5.41 STABLE --
Substrate

Channel Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Sep 26 2023
VCD-3 DA:0.61 ac C:0.6 I:7.26in/hr
Trapezoidal Highlighted
Bottom Width (ft) = 2.00 Depth (ft) = 0.37
Side Slopes (z:1) = 3.00, 2.00 Q (cfs) = 2.660
Total Depth (ft) = 2.00 Area (sqft) = 1.08
Invert Elev (ft) = 600.00 Velocity (ft/s) = 2.46
Slope (%) = 2.00 Wetted Perim (ft) = 4.00
N-Value = 0.035 Crit Depth, Yc (ft) = 0.33
Top Width (ft) = 3.85
Calculations EGL (ft) = 0.46
Compute by: Known Q
Known Q (cfs) = 2.66
Elev (ft) Section Depth (ft)
603.00 3.00
602.50 2.50
602.00 2.00
601.50 1.50
601.00 1.00
600.50 0 0.50
600.00 0.00
599.50 -0.50
0 2 4 6 8 10 12 14 16
Reach (ft)

741 NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> >VCD-3
Name VCD-3
Discharge 2.66
Channel Slope 0.02
Channel Bottom Width 2
Left Side Slope 3
Right Side Slope 2
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Good 65-79%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 2.66 cfs 2.5 ft/s 0.37 ft 0.035 1.6 Ibs/ft2 0.46 Ibs/ft2 3.51 STABLE D
Underlying Straight 2.66 cfs 2.5 ft/s 0.37 ft 0.035 1.74 Ibs/ft2 0.33 Ibs/ft2 5.21 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 2.66 cfs 2.5 ft/s 0.37 ft 0.035 4 Ibs/ft2 0.46 lbs/ft2 8.77 STABLE --
Vegetation
Underlying Straight 2.66 cfs 2.5 ft/s 0.37 ft 0.035 2.3 Ibs/ft2 0.33 lbs/ft2 6.87 STABLE --
Substrate

Channel Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Sep 26 2023
VCD-4 DA:0.57ac C:0.6 I:7.26in/hr
Trapezoidal Highlighted
Bottom Width (ft) = 2.00 Depth (ft) = 0.36
Side Slopes (z:1) = 3.00, 2.00 Q (cfs) = 2.480
Total Depth (ft) = 2.00 Area (sqft) = 1.04
Invert Elev (ft) = 600.00 Velocity (ft/s) = 2.38
Slope (%) = 2.00 Wetted Perim (ft) = 3.94
N-Value = 0.035 Crit Depth, Yc (ft) = 0.32
Top Width (ft) = 3.80
Calculations EGL (ft) = 0.45
Compute by: Known Q
Known Q (cfs) = 2.48
Elev (ft) Section Depth (ft)
603.00 3.00
602.50 2.50
602.00 2.00
601.50 1.50
601.00 1.00
600.50 v 0.50
600.00 0.00
599.50 -0.50
0 2 4 6 8 10 12 14 16
Reach (ft)

741 NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> >VCD-4
Name VCD-4
Discharge 2.48
Channel Slope 0.02
Channel Bottom Width 2
Left Side Slope 3
Right Side Slope 2
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Good 65-79%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 2.48 cfs 2.45 ft/s 0.35 ft 0.035 1.6 Ibs/ft2 0.44 Ibs/ft2 3.64 STABLE D
Underlying Straight 2.48 cfs 2.45 ft/s 0.35 ft 0.035 1.74 Ibs/ft2 0.32 lbs/ft2 5.37 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 2.48 cfs 2.45 ft/s 0.35 ft 0.035 4 Ibs/ft2 0.44 lbs/ft2 9.11 STABLE --
Vegetation
Underlying Straight 2.48 cfs 2.45 ft/s 0.35 ft 0.035 2.3 Ibs/ft2 0.32 lbs/ft2 7.08 STABLE --
Substrate

Channel Report
Hydraflow Express Extension for Autodesk®AutoCAD®Civil 3D®by Autodesk, Inc. Tuesday,Sep 26 2023
VCD-5 DA:0.38ac C:0.6 I:7.26in/hr
Trapezoidal Highlighted
Bottom Width (ft) = 2.00 Depth (ft) = 0.29
Side Slopes (z:1) = 3.00, 2.00 Q (cfs) = 1.660
Total Depth (ft) = 2.00 Area (sqft) = 0.79
Invert Elev (ft) = 600.00 Velocity (ft/s) = 2.10
Slope (%) = 2.00 Wetted Perim (ft) = 3.57
N-Value = 0.035 Crit Depth, Yc (ft) = 0.25
Top Width (ft) = 3.45
Calculations EGL (ft) = 0.36
Compute by: Known Q
Known Q (cfs) = 1.66
Elev (ft) Section Depth (ft)
603.00 3.00
602.50 2.50
602.00 2.00
601.50 1.50
601.00 1.00
600.50 0.50
v
600.00 0.00
599.50 -0.50
0 2 4 6 8 10 12 14 16
Reach (ft)

741 NORTH North American Green
AMERICAN 5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
GREEN Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> >VCD-5
Name VCD-5
Discharge 1.66
Channel Slope 0.02
Channel Bottom Width 2
Left Side Slope 3
Right Side Slope 2
Low Flow Liner
Retardence Class C 6-12 in
Vegetation Type Mix(Sod and Bunch)
Vegetation Density Good 65-79%
Soil Type Clay Loam(CL)
S75
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Remarks
Depth Mannings N Shear Stress Shear Stress Factor Pattern
S75 Unvegetated Straight 1.66 cfs 2.17 ft/s 0.28 ft 0.035 1.6 Ibs/ft2 0.35 Ibs/ft2 4.53 STABLE D
Underlying Straight 1.66 cfs 2.17 ft/s 0.28 ft 0.035 1.74 Ibs/ft2 0.27 lbs/ft2 6.44 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 1.66 cfs 2.17 ft/s 0.28 ft 0.035 4 Ibs/ft2 0.35 lbs/ft2 11.34 STABLE --
Vegetation
Underlying Straight 1.66 cfs 2.17 ft/s 0.28 ft 0.035 2.3 Ibs/ft2 0.27 lbs/ft2 8.48 STABLE --
Substrate

WATER QUALITY CALCULATIONS
FOR
BRIGHTON PARK
MOUNT PLEASANT, CABARRUS COUNTY, NC
PREPARED BY:
LATHAM-WALTERS ENGINEERING, INC.
16507-A NORTHCROSS DRIVE
HUNTERSVILLE, N.C. 28078
Phone: [phone] Fax: [phone]
N.C. Corporate License C-1815
FOR
NIBLOCK HOMES,LLC
759 CONCORD PARKWAY NORTH SUITE 20
CONCORD,NC 28027
DATE: FEBRUARY 14, 2022
`o.�\F°E S/°
o Quo 04,°
SE L o
356 g _
FNGINE�JQ'
OS L.
REVISED: 6/4/2022
REVISED: 8/5/2022
REVISED: 2/9/2023
REVISED: 6/1/2023

Carlos L. Ruano P.E.
Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Huntersville, NC 28078
Brighton Park BMP Design Summary
Brighton Park, located in Mt. Pleasant off Hwy-73, is a residential consisting of 178 single-family
lots. Sand Filters were computed & design according to the latest edition of NCDEQ Stormwater BMP
Manual, Mt. Pleasant Development Ordinance. Rainfall data came from the City of Concord Technical
Standards Manual as it was the nearest city close to Mt. Pleasant with recorded values. Post stormwater
run-off will be less or equal to pre-development values. BMPs were designed to the first one inch, 1 &
10-year storms; and spillways were designed for the 50-year storm.The first% inch of runoff and release
the stored volume in not less than 18 hours and not more than 36 hours.
Soil identity& aerial maps were inserted from Cabarrus County GIS. Curve Numbers (CN) will be
weighted per Mt. Pleasant Zoning & Hydrologic soil groups were computed from the Soil Survey of
Cabarrus County, NC. 5 min time of concentration was used for post-development.

Environmental
NCDEQ Stormwater Design Manual Quarry
Table of Contents
Guidance on the MDC
MDC 1: SHWT Separation
MDC 2: Two Chamber System
MDC 3: Sediment/Sand Chamber Sizing
MDC 4: Maximum Pondinq Depth
MDC 5: Flow Distribution
MDC 6: Sand Media Specification
MDC 7: Media Depth
MDC 8: Maintenance of Media
MDC 9: Clean-out Pipes
Recommendations
Recommendation 1: Drainage Area
Recommendation 2: Access to Underground Sand Filters
Maintenance
Old Versus New Design Standards
Figure 1: Open Bottom Sand Filter Example: Cross-Section
OPTIONAL FLOW DIVERSION TEMPORARY WATER SURFACE GRAVEL/STONE SURFACE
STRUCTURE
CLEANOUT— SAND FILTER MEDIA PROPOSED GRADE
SEDIMENT (PROVIDE AT (ASTM C 33 SAND OR
INFLOW CHAMBER LEAST ONE) EQUIVALENT) OVERFLOW
—� -----` (FOREBAY)
�•iiiiiiiii Piisi 0•iiiii 0i �
3: ,.......................4........................ Q
SLOPE °:�3:: %3:�:�.�:�.:�:�.�:�:; ::::
o.❖.•.O❖.O❖.O❖.•O.❖.�..� Fo
PERFORATED STANDPIPE Z 3:1
DETENTION STRUCTURE co? - g .; ..!J SLOPE
IN-SITU SOIL d OUTFLOW
PERFORATED PIPE—l/ \—SOLID PIPE
SEASONAL HIGH `V
WATER TABLE
NOTES: —
THE MINIMUM COMBINED VOLUME OF SEDIMENT CHAMBER AND STORAGE ABOVE SAND
FILTER MEDIA IS 0.75 TIMES THE TREATMENT VOLUME.
MAINTAIN SAND FILTER MEDIA SUCH THAT THE INFILTRATION RATE IS GREATER THAN OR
EQUAL TO 2 INCHES PER HOUR(2"/HR).
C-6. Sand Filter 2 Revised: 11/20/2020

0
Environmental
NCDEQ Stormwater Design Manual Quarry
Guidance on the MDC
SAND FILTER MDC 1. SHWT SEPARATION.
The minimum separation between the lowest point of the sand filter system and the SHWT
shall be:
(a) two feet for open-bottom designs; and
(b) one foot for closed bottom designs. Exceptions to the one-foot SHWT separation may
be made if the applicant provides documentation that the design will neither float nor
drain the water table.
In order to demonstrate that a closed system did not require a one-foot separation from the
SHWT, the designer will typically provide flotation calculations and specify an enclosure that will
not allow seepage from the groundwater into the sand filter system.
SAND FILTER MDC 2. TWO CHAMBER SYSTEM.
The sand filter shall include a sediment chamber and a sand chamber. Storage volume in
each chamber shall be equivalent.
The term "sand filter" is used to refer to the entire SCM, which comprises a sediment chamber
and a sand chamber. The sediment chamber serves as a forebay for the sand chamber, which
is the main treatment area of the sand filter system. The sediment chamber may be designed to
have a permanent pool of water or with orifices that allow it to drain between storm events. If
the sediment chamber has a permanent pool, then the volume contained by the permanent pool
shall not be considered to be storage volume. The sediment chamber can be oversized to
provide detention when peak flow mitigation is required for a site. The sand chamber will
typically be equipped with an underdrain surrounded by aggregate to drain the sand chamber
between storm events.
Figure 5: Two Cross-Sections of Closed-Bottom Sediment and Sand Chambers
INLET GRATE INLET SURFACE GRADE
GRATE
TEMPORARY
TEMPORARY PONDING
UI
PONDING
-. SAND FILTER SAND FILTER
` FILTR-, FILTER FABRIC�� MEDIUM; ! AGGRIGATE o 0 0 2AGGRIGATE�� OUTLET PIPE
0 OUTLET PIPE
CONCRETE CONCRETE
C-6. Sand Filter 5 Revised: 11/20/2020

NCDEQ Stormwater Design Manual Environmental
SAND FILTER MDC 3. SEDIMENT/SAND CHAMBER SIZING.
The volume of water that can be stored in the sediment chamber and the sand chamber
above the sand surface combined shall be 0.75 times the treatment volume. The elevation
of bypass devices shall be set above the ponding depth associated with this volume. The
bypass device may be designed to attenuate peak flows.
The area required for a sand filter device is calculated similarly to many other SCMs:
1. Calculate the design volume.
2. Multiply the design volume by 0.75, a "discount" that is allowed because stormwater
infiltrates so rapidly through the sand media that the stormwater is treated throughout
the storm event. By the end of the storm, the runoff from the beginning of the storm has
already been treated and has exited the sand filter.
3. Divide the discounted design volume by the ponding depth, this will be the minimum
surface area of the sand filter.
4. If the sand filter is designed to attenuate peak flows, additional surface area may be
added in the sediment chamber only. The sand filter must be designed so that 50% of
the treatment volume can be stored in the sand chamber below the first bypass device.
There are no MDC related to the shape of the sand filter. One of the biggest advantages of
sand filters is how easily they can be fit to the site. Open-bottom sand filters can be rectangular,
square, circular or irregular. Closed bottom sand filters are usually rectangular.
SAND FILTER MDC 4. MAXIMUM PONDING DEPTH.
The maximum ponding depth from the top of the sand to the bypass device shall be six feet.
The ponding depth is limited to six feet in order to avoid overloading the sand chamber. The
designer is allowed to design the sand filter for peak flow attenuation as long as the six-foot
ponding depth is not exceeded.
SAND FILTER MDC 5. FLOW DISTRIBUTION.
Incoming stormwater shall be evenly distributed over the surface of the sand chamber.
Stormwater flow may be distributed over the surface of the sand chamber via a level spreader, a
pipe distribution system, or a series of weirs.
SAND FILTER MDC 6. SAND MEDIA SPECIFICATION.
Sand media shall meet ASTM C33 or the equivalent.
The media in the sand filter shall be cleaned, washed, course masonry sand such as ASTM
C33 or the equivalent. The sand particles shall be less than 2 mm average diameter. The
entire surface area of the sand chamber must contain sand.
C-6. Sand Filter 6 Revised: 11/20/2020

Environmental
NCDEQ Stormwater Design Manual Quality
SAND FILTER MDC 7. MEDIA DEPTH.
The filter bed shall have a minimum depth of 18 inches. The minimum depth of sand above
the underdrain pipe shall be 12 inches.
The filter bed shall have a minimum depth of 18 inches, with a minimum depth of sand above
the drainage pipe of 12 inches.
SAND FILTER MDC 8. MAINTENANCE OF MEDIA.
The sand filter shall be maintained in a manner that results in a drawdown of at least two
inches per hour at the sand surface.
The easiest way to determine if the sand media is infiltrating adequately is to divide the depth of
sand by two inches per hour (the minimum allowed infiltration rate) to determine the maximum
number of hours that stormwater should take to drain through the sand chamber. For example,
if the sand is 18 inches deep, the sand chamber should drain in 9 hours or less. When the
filtering capacity has diminished below this level, then remedial actions shall be taken. The first
step is to remove the top few inches of media replace it with fresh media. The removed
sediments should be disposed of in an acceptable manner (e.g., landfill). If the problem still
persists, then all of the sand media may need to be replaced.
SAND FILTER MDC 9. CLEAN-OUT PIPES.
At least one clean-out pipe shall be provided at the low point of each underdrain line. Clean
out pipes shall be capped.
For the clean-out, it is recommended to specify a PVC pipe that has glued clean-out fittings
with screw type caps. It is crucial that the cap be secure so that the stormwater will not leave
the sand filter via the pipe rather than passing through the sand media as intended. In
addition, the ends of each underdrain pipe should be capped to prevent clogging of the
underdrain system.
Recommendations
SAND FILTER RECOMMENDATION 1. DRAINAGE AREA.
It is recommended to grade pervious areas to drain away from sand filters and to limit the
drainage area of a sand filter to five acres or less.
Sand filters will function much better when the drainage area is highly built-upon because this
will greatly reduce the amount of fines that reach the sand filter and potentially cause clogging.
It is particularly important to grade pervious surfaces to drain away from the sand filter in areas
with C and D soils. There is no maximum drainage area for sand filters; however, sand filters
with smaller drainage areas (less than five acres) usually have fewer maintenance issues.
Multiple sand filters can be used throughout a development to provide treatment for larger sites.
C-6. Sand Filter 7 Revised: 11/20/2020

NC Environmental
NCDEQ Stormwater Design Manual QaarirY
B. Stormwater Calculations
Stormwater programs in North Carolina require high density projects to treat the design storm
depth in a stormwater control measure (SCM). To size the SCM, the designer must calculate
the volume of runoff that will drain to it. Additional calculations are needed to design the outlet
structures of SCMs.
The stormwater rules do not reference any calculation methods. This chapter provides
technical guidance for stormwater calculation methods that are typically used in North Carolina.
Table of Contents
• Rational Method for Peak Flow
• Simple Method for Runoff Volume
• Discrete NRCS Curve Number Method for Runoff Depth
• Stage-Storage Tables for Storage Volume of Ponds
• Weir Equations for Outlet Flow
• Orifice Equation for Outlet Flow
• Chainsaw Routing for Stage-Storage-Discharge
• Other Models for Staqe-Storage-Discharge
• Manning Equation for Channel Flow
Rational Method for Peak Flow
Qp = C * I * A
Where: Qp = Peak flow for the storm of interest (cfs)
C = Composite runoff coefficient (unitless)
I = Rainfall intensity for the storm of interest (in/hr)
A = Drainage area (ac)
The peak flow is often calculated using the Rational Method. Calculating the peak flow is an
important design step in designing a flow-based device such as a level spreader-filter strip. It is
also important to meet SA waters requirements per 15A NCAC 02H .1019.
The composite runoff coefficient, C, reflects the runoff potential of the drainage area. The range
of runoff coefficients varies from 0.35 to 0.95, with higher values corresponding to greater runoff
potential. The composite runoff coefficient is the weighted average of all of the land uses within
the drainage area. Table 1 presents values of runoff coefficients for various surfaces. The
Rational Method is most applicable to drainage areas that are 20 acres or less.
B. Stormwater Calculations 1 Revised: 3-15-2017

NC Environmental
NCDEQ Stormwater Design Manual QaarirY
Table 1: Rational Runoff Coefficients by Land Use
(ASCE 1975, Viessman, et al. 1996, and Malcom 1999)
Description of Surface Rational Runoff Coefficient, C
Unimproved Areas 0.35
Asphalt 0.95
Concrete 0.95
Brick 0.85
Roofs, inclined 1.00
Roofs, flat 0.90
Lawns, sandy soil, flat (<2%) 0.10
Lawns, sandy soil, average (2-7%) 0.15
Lawns, sandy soil, steep (>7%) 0.20
Lawns, heavy soil, flat (<2%) 0.15
Lawns, heavy soil, average (2-5%) 0.20
Lawns, heavy soil, steep (>7%) 0.30
Wooded areas 0.15
The rainfall intensity in inches per hour, I, can be obtained from the NOAA web site. From this
web site, select from one of NOAA's numerous data stations throughout the state and select
"precipitation intensity." This will open a table that displays precipitation intensity estimates for
various annual return intervals (ARIs) (one year through 1,000 years) and various storm
durations (5 minutes through 60 days). The requirements of the applicable stormwater
program will determine the appropriate values for ARI and storm duration. If the design is for a
level spreader that is receiving runoff directly from the drainage area, then the value for I should
simply be one inch per hour (more information on level spreader design in Chapter 8).
Simple Method for Runoff Volume
Rv = 0.05 + 0.9 * IA
Where: Rv = Runoff coefficient (unitless)
IA = Impervious fraction (unitless)
DV = 3630 * RD * Rv * A
Where: DV = Design volume (cu ft)
RD = Design storm depth (in)
A = Drainage area (ac)
B. Stormwater Calculations 2 Revised: 3-15-2017

NCDEQ Stormwater BMP Manual
Environmental
Quality
soils if the applicant provides a soils report that demonstrates that the modified
soil profile allows for infiltration of the design volume within 72 hours or less.
The drawdown time requirement, in combination with the field-determined soil
infiltration rate, determines the minimum surface area for an infiltration system.
See Equation 1 below.
Equation 2: Minimum Surface Area for an Infiltration System
DV *12
SA = FS * K * T
where: SA = required minimum surface area of infiltration system (ft2)
FS = factor of safety (minimum of 2 is recommended)
DV = design volume (ft3)
K = hydraulic conductivity of soil (in/hr)
T = maximum dewatering time (72 hours)
Although some infiltration will likely occur from the sides of an infiltration system,
the DEQ recommends sizing the infiltration system's bottom surface area per this
equation and considering infiltration from the sides as a factor of safety.
A factor of safety is crucial in infiltration system design due to the following:
• The inherent uncertainty in soil testing;
• The likelihood that the soil will be compacted during construction, which can
reduce soil infiltration rates by more than an order of magnitude; and
• The likelihood that sediment will enter the infiltration system after it is
constructed and diminish the infiltration rate. If the system does not drain
within 72 hours throughout its operational life, then it will be out of
compliance with this MDC.
INFILTRATION MDC 6: OBSERVATION PORT.
For infiltration devices located under the ground surface, a minimum of one
inspection port shall be provided.
In order to monitor performance of the infiltration device, observations should be
conducted to determine how long it takes retained water to infiltrate into the soil
after a storm event
Recommendations
INFILTRATION RECOMMENDATION 1: TRENCH MEDIA. =I=
C-1. Infiltration System 7 Revised: 11-20-2020

MOUNT PLEASANT DEVELOPMENT ORDINANCE Article 10
involved,and approved by town Public Works Director or their designee will be considered. Any concrete pipe
laid between the concrete curbs shall be reinforced. All pipe shall be laid with the bell or groove upgrade and
joint entirely interlocking.
M. Catch basins shall be built as shown on the standard drawings. Improvised grates will not be acceptable. Catch
basins walls shall be built straight with inside joints struck smooth.Precast catch basins may be acceptable with
the approval of the town Public Works Director or their designee.
10.3.5. DETENTION FACILITY DESIGN STANDARDS
A. The detention facility must limit the 1-year and 10-year developed discharge rates to pre-developed peak
discharge rates. Emergency spillways shall be designed to accommodate 50-year frequency storms or as may be
required by the North Carolina Dam Safety Law.In areas specifically designated as sensitive water quality areas,
[for example, within watershed protection overlay districts and the River/Stream Overlay District (RSOD) or
other applicable Overlay Districts the more stringent design criteria applies.
B. Design and installation of all storm water detention or other impoundment facilities shall comply with applicable
federal,state and local laws.
C. In no case,shall a habitable structure be located within the impoundment area of any storm water detention facility
or over a storm water drainage line.
D. No utilities (sanitary sewer lines, underground power lines, water lines, etc.) shall be located within any
impoundment facility.
E. No structures may be located over storm drain lines not associated with the detention system.
F. Impoundment facilities located within automobile parking areas shall not exceed a maximum water depth of ten
(10)inches.
G. All impoundment facilities will be considered permanent.
H. Maintenance of all impoundment or detention facilities will be the responsibility of the property owner.Adequate
provisions for such private maintenance shall be included in a declaration of covenants for subdivisions which
shall be approved by the Town Board and recorded by the Cabarrus County Register of Deeds. Stormwater
management plans shall be developed for site developments not associated with a subdivision development and
shall be approved by the Public Works Director and recorded by the Cabarrus County Register of Deeds.Failure
to maintain a storm water detention or impoundment facility shall be considered a violation of this ordinance and
shall be subject to penalties as set forth in Article 1.6 of this Ordinance.
I. Impoundment or detention facilities which may impact existing storm drainage systems may be required to be
protected by a"drainage detention easement"recorded by the Cabarrus County Register of Deeds.
J. Impoundment facilities which may impact existing storm drainage systems may be required to be protected by a
"drainage detention easement"recorded by the Cabarrus County Register of Deeds.
K. Detention facilities within areas specifically designated as sensitive water quality areas, (for example, within
protected water supply watersheds or stream riparian buffers)shall comply with the regulations and design criteria
for those areas.
L. Vegetated and rip-rap protected embankments shall have side slopes no steeper than 3:1 (h:v)within open spaces
10-22

MOUNT PLEASANT DEVELOPMENT ORDINANCE Article 10
and no steeper than 2:2(h:v)elsewhere,and shall meet requirements of the Dam Safety Act when necessary.
M. Impoundment facilities located within automobile parking areas shall not exceed a maximum water depth of six
(6)inches in code-required parking areas, 10 inches in additional parking area,and 15 inches in truck storage and
loading areas.
N. The stormwater detention facilities in High Quality Water(HQW) or source water protection areas shall detain
the first Y2 inch of runoff and release the stored volume in not less than 18 hours and not more than 36 hours.
O. The following hydrologic soil groups shall apply for Cabarrus County,North Carolina:
Series Name Hydrologic Group
Altavista C
Appling B
Armenia D
Badin C
Cecil B
Chewacla C
Coronaca B
Cullen C
Enon C
Georgeville B
Goldston C
Herndon B
Hewassee B
Iredell C/D
Kirksey C
Mecklenburg C
Misenheimer C
Pacolet B
Poindexter B
Sedgefield C
Tatum C
Vance C
Wehadkee D
Source:United States Department of Agriculture, Soil Conservation Service,Soil Survey of Cabarrus
County,North Carolina,Table 16.Page 86 and pages 124-126 of the Soil Survey of Cabarrus County,
North Carolina shows permeability ratings by depth and type for each soil type.
P. Stormwater detention or impoundment facilities shall be located on the site from which the run-off to be
controlled is generated;provided,however,that off-site impoundment facilities are acceptable provided the
land area involved within the facility is delineated on an acceptable map and officially recorded by the
Cabarrus County Register of Deeds as a permanent "drainage detention easement." Regional detention
facilities are allowed if approved by the Public Works Director or their designee and if the development plans
provide for the proper operation, inspection, and maintenance of the facilities in perpetuity through a
restrictive covenant or other legal,enforceable mechanism.
Q. Stormwater facilities to be located in designated open space areas shall be regulated in accordance with
Article 6 of this Ordinance.
10-23

Cabarrus County, North Carolina 127
TABLE 16.--SOIL AND WATER FEATURES
["Flooding" and "water table" and terms such as "rare," "brief," "apparent," and "perched" are explained in the
text. The symbol < means less than; > means more than. Absence of an entry indicates that the feature is
not a concern or that data were not estimated]
Flooding High water table Bedrock Risk of corrosion
Map symbol and Hydro-
soil name logic Frequency Duration Months Depth Kind !Months Depth Hard- Uncoated Concrete
group f ness steel
Ft In
AaB C Rare --- --- 1.5-2.5 Apparent Dec-Mar >60 --- Moderate Moderate.
Altavista
ApB B None --- --- >6.0 --- --- >60 --- Moderate Moderate.
Appling
Ar D Rare --- --- 0.5-1.5 Apparent Dec-Apr >60 --- High Low.
Armenia
BaB, BaD, BaF C None --- --- >6.0 --- --- 20-40 Soft High High.
Badin 40-60 Hard
CcB2, CcD2 B None --- --- >6.0 --- --- >60 --- Moderate Moderate.
Cecil
CeB:
Cecil B None --- --- >6.0 --- --- >60 --- Moderate Moderate.
Urban land.
Ch C Frequent---- Brief Nov-Apr 0.5-1.5 Apparent Nov-Apr >60 --- High Moderate.
Chewacla
CoB, CoD B None --- --- >6.0 --- --- >60 --- High Moderate.
Coronaca
CuB2, CuD2 C None --- --- >6.0 --- --- >60 --- High Moderate.
Cullen
EnB, EnD C None --- --- >6.0 --- --- >60 --- High Moderate.
Enon
EoB:
Enon C None --- --- >6.0 --- --- >60 --- High Moderate.
Urban land.
GeB2 B None --- --- >6.0 --- --- >60 --- High High.
Georgeville
GoC, GoF C None --- --- >6.0 --- --- 10-20 Soft Moderate High.
Goldston 20-40 Hard
HeB B None --- --- >6.0 --- --- >60 --- High High.
Herndon
1wB, HwD B None --- --- >6.0 --- --- >60 --- Moderate Moderate.
Hiwassee
IdA, IdB C/D None --- --- 1.0-2.0 Perched Dec-Apr >40 Soft High Low.
Iredell
(kB C None --- --- 1.5-3.0 Perched Dec-Mar 40-60 Soft Moderate High.
Kirksey

128 Soil Survey
TABLE 16.--SOIL AND WATER FEATURES--Continued
Flooding High water table Bedrock Risk of corrosion
Map symbol and Hydro-
soil name logic Frequency Duration Months Depth Kind Months Depth Hard- Uncoated Concrete
group ness steel
Ft In
MeB, MeD C None --- --- >6.0 --- --- 48-60 Soft High Moderate.
Mecklenburg
MkB:
Mecklenburg C None --- --- >6.0 --- --- 48-60 Soft High Moderate.
Urban land.
MsA C None --- --- 1.0-1.5 Perched Dec-May 10-20 Soft High High.
Misenheimer 20-40 Hard
PaF B None --- --- >6.0 --- --- >60 --- High High.
Pacolet
PcE3:
Pacolet B None --- --- >6.0 --- --- >60 --- High High.
Udorthents.
PoB, PoD, PoF B None --- --- >6.0 --- --- 20-40 Soft Moderate Moderate.
Poindexter 40-60 Hard
SfB C None --- --- 1.0-1.5 Perched Jan-Mar >48 Hard High Moderate.
Sedgefield
TaB, TaD, TbB2,
TbD2 C None --- --- >6.0 --- --- 40-60 Soft High High.
Tatum
Ud.
Udorthents
Ur.
Urban land
VaB, VaD C None --- --- >6.0 --- --- >60 Soft High High.
Vance
We D Frequent---- Brief Nov-Jun 0-2.5 Apparent Dec-May >60 --- High Moderate.
Wehadkee

SECTION 2
STORMWATER RUNOFF
TABLE 2-1
APPROXIMATE 24-HOUR RAINFALL
VOLUMES FOR CONCORD,NC
Return Interval 24-hour Volume(inches)
1-year 2.9
2-year 3.5
5-year 4.4
10-year 5.1
25-year 6.0
50-year 6.8
100-year 7.6
2.2.2 Intensity-Duration-Frequency Curves
Intensity-duration-frequency (IDF) curves have been developed for the area and are shown in
Figure 2-2, on page 2-5. The curves for 1-, 2-, 5-, 10-, 25-, 50-, and 100-year storm events with
durations from 5 minutes to 24 hours. Ordinates from the Figure 2-2 have been provided in
Table 2-3, on page 2-5.
2.2.3 Design Storm Recurrence Intervals
The selection of the recurrence interval to be used for the design storm shall be in accordance with
Section 1.3,Design Policy.
Adopted January 10, 2008 2-2 Technical Standards Manual

SECTION 2
STORMWATER RUNOFF
TABLE 2-10
RUNOFF CURVE NUMBER FOR URBAN AREAS AND OTHER
AGRICULTURAL LANDS'
Average Percent Curve Numbers for
Cover Description Hydrologic Soil Group
Cover Type and Hydrologic Condition Impervious
Area2 A BC D
Fully developed urban areas(vegetation established)
Open space(lawns,parks,golf courses,cemeteries,etc.)3
Poor Condition(grass cover<50 percent) 68 79 86 89
Fair Condition(grass cover 50 to 75 percent) 49 69 79 84
Good Condition(grass cover>75 percent) 39 61 74 80
Impervious areas:
Paved parking lots,roofs,driveways,etc.,(excluding
right-of-ways) 98 98 98 98
Streets and roads:
Paved;curbs and storm sewers(excluding right-of-
ways) 98 98 98 98
Paved;open ditches(including right-of-ways) 83 89 92 93
Gravel(including right-of-ways) 76 85 89 91
Dirt(including right-of-ways) 72 82 87 89
Urban districts:
Commercial and business 85 89 92 94 95
Industrialf 72 81 88 91 93
Residential districts by average lot size:
RE-maximum of 1 dwelling per acre 20 51 68 79 84
RL-maximum of 2 dwellings per acre 25 54 70 80 85
RM-1 -maximum of 3 dwellings per acre 30 57 72 81 86
RM-2-maximum of 4 dwellings per acre 38 61 75 83 87
RV-maximum of 8 dwelling/acre 65 77 85 90 92
RC-maximum of 15 dwelling/acre 80 86 90 93 96
Developing urban areas and agricultural land
Newly graded areas(pervious areas only,no vegetation)4 77 86 91 94
Pasture,grassland,or range—continuous forage for grazing5 Poor 68 79 86 89
Fair 49 69 79 84
Good 39 61 74 80
Meadow-continuous grass,protected from grazing and - 30 58 71 78
generally mowed for hay
Brush-brush,weed,grass mixture with brush the major Poor 48 67 77 83
elements6 Fair 35 56 70 77
Good 730 48 65 73
Woods-grass combination(orchard or tree farm)8 Poor 57 73 82 86
Fair 43 65 76 82
Good 32 58 72 79
Woods9 Poor 45 66 77 83
Fair 36 60 73 79
Good 430 55 70 77
Farmsteads-buildings,lanes,driveways,and surrounding lots. - 59 74 82 86
Source: SCS,Urban Hydrology for Small Watersheds,Technical Release No.55.
Adopted January 10, 2008 2-25 Technical Standards Manual

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Brighton Park Subdivision Appendices
Rip Rap Apron Design
30 .. 1 I ,
im
Outlet W = Do + La 90i
m iii a 1ii'ii I�k
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Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Tw<0.5 diameter).
SEE SPREADSHEET
Rev. 12i93 8.06.3

Brighton Park Subdivision
Rip Rap Apron Design
Diameter Diameter d50(in) d50 d50(in) Thickness Class
Structure Q(cfs) (in) (ft) La(ft) W(ft) 3Do(ft) MIN (in) MAX (in) Riprap
FES-53 8 15 1.25 10 11 4 5 8 12 18 B
FES-26 6 18 1.5 10 12 5 5 8 12 18 B
FES-130 21 24 2 12 14 6 5 8 12 18 B
FES-30 39 30 2.5 16 19 8 5 8 12 18 B
FES-128 9 15 1.25 10 11 4 5 8 12 18 B
FES-106 16 24 2 12 14 6 5 8 12 18 B
FES-68 3 18 1.5 10 12 5 5 8 12 18 B
HW-1 7 18 1.5 10 12 5 5 8 12 18 B
FES-79 22 24 2 12 14 6 5 8 12 18 B
HW-5 3 15 1.25 10 11 4 5 8 12 18 B
FES-104 3 15 1.25 10 11 4 5 8 12 18 B
FES-88 25 30 2.5 16 19 8 5 8 12 18 B
FES-8 21 30 2.5 16 19 8 5 8 12 18 B
Pipe(in)
15 18 24 30
IF Q<8cfs Q<10cfs Q<20cfs Q<35cfs
Min La(ft) 10 10 12 16
Min d50(ir 8 8 8 8
Min T(in) 18 18 18 18

Brighton Park Subdivision Appendices
BMP Rip Rap Apron Design
30
Outlet W = Do 4- La 90 • `:i IIII
pipe
diameter (Do) I. Cii■u Ii a•
i ` . �,,,.1 .1,
La -.1 80 _ •■■1■ • I,,filllr
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3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(Ty.,<0.5 diameter).
BMP 1 BMP2 BMP3 BMP4 BMP5 BMP6
Q:21 cfs Q: 3 cfs Q: 7.7 cfs Q: 6.6 cfs Q: 16 cfs Q: 8.7 cfs
Do: 36" Do: 18" Do: 18" Do: 18" Do: 18" Do: 18"
3Do: 9' 3Do:4.5' 3Do:4.5' 3Do:4.5' 3Do:4.5' 3Do:4.5'
La:20' La: 10' La: 10' La: 10' La: 10' La: 10'
W: 23' W: 11.5' W: 11.5' W: 11.5' W: 11.5' W: 11.5'
d50: 0.6' d50: 0.5' d50: 0.5 d50: 0.5 d50: 0.5 d50:0.5
Rev. 12r93 8.06.3

SAND FILTER-1
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Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 1
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 18.23 ac
Impervious area to filter forebay= 8.89 ac.
Impervious percentage= 48.76%
Rv=0.05+0.9(la) = 0.4888457
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 32349 cf (used to size Af)
WQV= 0.7426 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
611 15196 0 0
612 18261 16728.5 16728.5
613 19907 19084 35812.5
614 21553 20730 56542.5
615 23311 22432 78974.5
616 25068 24189.5 103164
617 26940 26004 129168
618 28812 27876 157044
Calculate Depth for WQ Volume:
612 16728.5
612.78 32349
614 56542.5
Elevation of WQ Volume= 612.78
3. Discount WQv:
0.75 x WQv 24261.99 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 72.0
Cn Post= 83.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 12.63 42.60 56.44 69.25
Post. Dev. 46.3 107.38 132.94 155.68
Routed 1.32 21.14 60.54 95.84
Peak Stage 613.92 616.16 616.78 617.19
Disch.Time 100 hours 0.81 Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
4044 SA(ft2) Dv"12
2 FS SA = FS" K"T
24262 DV(FT3) where: SA =required minimum surface area of infiltration system(fK)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(ft3)
K =hydraulic conductivity of soil(in/hr)
72 T(hours) T =maximum dewatering time(72 hours)
6.Sediment Sand Sizing(req'd)
24262 Design Volume(ft3)
12131 Sediment Chamber(ft3)
12131 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 673.9441 cf/hour 0.187 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
264 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 4224 holes
50%of perforations= 2112 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 17.5296 cfs which is 93.6 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
Dimensions of Riser
7.7 Height of Riser,ft. 4 ft L
16 Area of Riser,s.f. 4 ft W
123.2 Volume of Riser,c.f. 0.5 ft
7687.68 Weight of Water @ 62.4 pcf
8456.448 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
3.79 Volume of Concrete Req'd in c.y.
102.38 Volume of Concrete Req'd in c.f.
69.3 Volume of Concrete in Structure(cf)
33.08 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
0.5 ft thick
5.8 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 4044 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 26957.76 0.312
2 37740.87, 0.437
3 48523.97 0.562
4 59307.08 0.686
5 70090.18' 0.811
6 80873.29 0.936
7 91656.39 1.061
8 102439.5 1.186
9 113222.6' _1.310
10 124005.7 1.435
11 134788.8 _1.560
12 145571.9, 1.685
13 156355 1.810

11,
(Predeveloped)
AND
(Post Developed) (BMP1 )
(Subca) Reach Pon MI Drainage Diagram for 2020.17-BMP1
Prepared by{enter your company name here} 2/7/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP1
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
3.600 60 Woods, Fair, HSG B (1S)
9.340 69 50-75% Grass cover, Fair, HSG B (2S)
3.870 69 Pasture/grassland/range, Fair, HSG B (1S)
3.200 73 Woods, Fair, HSG C (1S)
7.560 79 Pasture/grassland/range, Fair, HSG C (1S)
8.890 98 Paved parking & roofs (2S)
36.460

2020.17-BMP1 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=18.230 ac Runoff Depth=0.75"
Flow Length=1,107' Tc=22.5 min CN=72 Runoff=12.63 cfs 1.138 af
Subcatchment 2S: (Post Developed) Runoff Area=18.230 ac Runoff Depth=1.37"
Tc=5.0 min CN=83 Runoff=46.30 cfs 2.076 af
Pond 3P: (BMP1) Peak Elev=613.92' Storage=54,727 cf Inflow=46.30 cfs 2.076 af
Primary=1.32 cfs 2.076 af Secondary=0.00 cfs 0.000 af Outflow=1.32 cfs 2.076 af
Total Runoff Area = 36.460 ac Runoff Volume = 3.214 af Average Runoff Depth = 1.06"
75.62% Pervious Area = 27.570 ac 24.38% Impervious Area = 8.890 ac

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 12.63 cfs @ 12.18 hrs, Volume= 1.138 af, Depth= 0.75"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
3.200 73 Woods, Fair, HSG C
3.600 60 Woods, Fair, HSG B
3.870 69 Pasture/grassland/range, Fair, HSG B
7.560 79 Pasture/grassland/range, Fair, HSG C
18.230 72 Weighted Average
18.230 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.7 100 0.0371 0.16 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.6 719 0.0672 1.81 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
5.2 288 0.0347 0.93 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
22.5 1,107 Total

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.75 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.75 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.75 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.75 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.75 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.75 0.00
12.00 1.92 0.26 5.57 116.00 2.90 0.75 0.00
14.00 2.38 0.47 1.15 118.00 2.90 0.75 0.00
16.00 2.55 0.56 0.71 120.00 2.90 0.75 0.00
18.00 2.67 0.62 0.55 122.00 2.90 0.75 0.00
20.00 2.76 0.67 0.41 124.00 2.90 0.75 0.00
22.00 2.83 0.71 0.37 126.00 2.90 0.75 0.00
24.00 2.90 0.75 0.35 128.00 2.90 0.75 0.00
26.00 2.90 0.75 0.00 130.00 2.90 0.75 0.00
28.00 2.90 0.75 0.00 132.00 2.90 0.75 0.00
30.00 2.90 0.75 0.00 134.00 2.90 0.75 0.00
32.00 2.90 0.75 0.00 136.00 2.90 0.75 0.00
34.00 2.90 0.75 0.00 138.00 2.90 0.75 0.00
36.00 2.90 0.75 0.00 140.00 2.90 0.75 0.00
38.00 2.90 0.75 0.00 142.00 2.90 0.75 0.00
40.00 2.90 0.75 0.00 144.00 2.90 0.75 0.00
42.00 2.90 0.75 0.00 146.00 2.90 0.75 0.00
44.00 2.90 0.75 0.00 148.00 2.90 0.75 0.00
46.00 2.90 0.75 0.00 150.00 2.90 0.75 0.00
48.00 2.90 0.75 0.00 152.00 2.90 0.75 0.00
50.00 2.90 0.75 0.00 154.00 2.90 0.75 0.00
52.00 2.90 0.75 0.00 156.00 2.90 0.75 0.00
54.00 2.90 0.75 0.00 158.00 2.90 0.75 0.00
56.00 2.90 0.75 0.00 160.00 2.90 0.75 0.00
58.00 2.90 0.75 0.00 162.00 2.90 0.75 0.00
60.00 2.90 0.75 0.00 164.00 2.90 0.75 0.00
62.00 2.90 0.75 0.00 166.00 2.90 0.75 0.00
64.00 2.90 0.75 0.00 168.00 2.90 0.75 0.00
66.00 2.90 0.75 0.00 170.00 2.90 0.75 0.00
68.00 2.90 0.75 0.00 172.00 2.90 0.75 0.00
70.00 2.90 0.75 0.00 174.00 2.90 0.75 0.00
72.00 2.90 0.75 0.00 176.00 2.90 0.75 0.00
74.00 2.90 0.75 0.00 178.00 2.90 0.75 0.00
76.00 2.90 0.75 0.00 180.00 2.90 0.75 0.00
78.00 2.90 0.75 0.00 182.00 2.90 0.75 0.00
80.00 2.90 0.75 0.00 184.00 2.90 0.75 0.00
82.00 2.90 0.75 0.00 186.00 2.90 0.75 0.00
84.00 2.90 0.75 0.00 188.00 2.90 0.75 0.00
86.00 2.90 0.75 0.00 190.00 2.90 0.75 0.00
88.00 2.90 0.75 0.00 192.00 2.90 0.75 0.00
90.00 2.90 0.75 0.00 194.00 2.90 0.75 0.00
92.00 2.90 0.75 0.00 196.00 2.90 0.75 0.00
94.00 2.90 0.75 0.00 198.00 2.90 0.75 0.00
96.00 2.90 0.75 0.00 200.00 2.90 0.75 0.00
98.00 2.90 0.75 0.00
100.00 2.90 0.75 0.00
102.00 2.90 0.75 0.00

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 46.30 cfs @ 11.96 hrs, Volume= 2.076 af, Depth= 1.37"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
8.890 98 Paved parking & roofs
9.340 69 50-75% Grass cover, Fair, HSG B
18.230 83 Weighted Average
9.340 Pervious Area
8.890 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.37 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.37 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.37 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.37 0.00
8.00 0.35 0.00 0.00 112.00 2.90 1.37 0.00
10.00 0.52 0.01 0.20 114.00 2.90 1.37 0.00
12.00 1.92 0.64 40.14 116.00 2.90 1.37 0.00
14.00 2.38 0.96 1.52 118.00 2.90 1.37 0.00
16.00 2.55 1.10 0.95 120.00 2.90 1.37 0.00
18.00 2.67 1.19 0.75 122.00 2.90 1.37 0.00
20.00 2.76 1.26 0.55 124.00 2.90 1.37 0.00
22.00 2.83 1.31 0.51 126.00 2.90 1.37 0.00
24.00 2.90 1.37 0.47 128.00 2.90 1.37 0.00
26.00 2.90 1.37 0.00 130.00 2.90 1.37 0.00
28.00 2.90 1.37 0.00 132.00 2.90 1.37 0.00
30.00 2.90 1.37 0.00 134.00 2.90 1.37 0.00
32.00 2.90 1.37 0.00 136.00 2.90 1.37 0.00
34.00 2.90 1.37 0.00 138.00 2.90 1.37 0.00
36.00 2.90 1.37 0.00 140.00 2.90 1.37 0.00
38.00 2.90 1.37 0.00 142.00 2.90 1.37 0.00
40.00 2.90 1.37 0.00 144.00 2.90 1.37 0.00
42.00 2.90 1.37 0.00 146.00 2.90 1.37 0.00
44.00 2.90 1.37 0.00 148.00 2.90 1.37 0.00
46.00 2.90 1.37 0.00 150.00 2.90 1.37 0.00
48.00 2.90 1.37 0.00 152.00 2.90 1.37 0.00
50.00 2.90 1.37 0.00 154.00 2.90 1.37 0.00
52.00 2.90 1.37 0.00 156.00 2.90 1.37 0.00
54.00 2.90 1.37 0.00 158.00 2.90 1.37 0.00
56.00 2.90 1.37 0.00 160.00 2.90 1.37 0.00
58.00 2.90 1.37 0.00 162.00 2.90 1.37 0.00
60.00 2.90 1.37 0.00 164.00 2.90 1.37 0.00
62.00 2.90 1.37 0.00 166.00 2.90 1.37 0.00
64.00 2.90 1.37 0.00 168.00 2.90 1.37 0.00
66.00 2.90 1.37 0.00 170.00 2.90 1.37 0.00
68.00 2.90 1.37 0.00 172.00 2.90 1.37 0.00
70.00 2.90 1.37 0.00 174.00 2.90 1.37 0.00
72.00 2.90 1.37 0.00 176.00 2.90 1.37 0.00
74.00 2.90 1.37 0.00 178.00 2.90 1.37 0.00
76.00 2.90 1.37 0.00 180.00 2.90 1.37 0.00
78.00 2.90 1.37 0.00 182.00 2.90 1.37 0.00
80.00 2.90 1.37 0.00 184.00 2.90 1.37 0.00
82.00 2.90 1.37 0.00 186.00 2.90 1.37 0.00
84.00 2.90 1.37 0.00 188.00 2.90 1.37 0.00
86.00 2.90 1.37 0.00 190.00 2.90 1.37 0.00
88.00 2.90 1.37 0.00 192.00 2.90 1.37 0.00
90.00 2.90 1.37 0.00 194.00 2.90 1.37 0.00
92.00 2.90 1.37 0.00 196.00 2.90 1.37 0.00
94.00 2.90 1.37 0.00 198.00 2.90 1.37 0.00
96.00 2.90 1.37 0.00 200.00 2.90 1.37 0.00
98.00 2.90 1.37 0.00
100.00 2.90 1.37 0.00
102.00 2.90 1.37 0.00

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP1)
Inflow Area = 18.230 ac, Inflow Depth = 1.37" for 1-yr Concord event
Inflow = 46.30 cfs @ 11.96 hrs, Volume= 2.076 af
Outflow = 1.32 cfs @ 14.62 hrs, Volume= 2.076 af, Atten= 97%, Lag= 159.3 min
Primary = 1.32 cfs @ 14.62 hrs, Volume= 2.076 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 613.92' @ 14.62 hrs Surf.Area= 21,414 sf Storage= 54,727 cf
Plug-Flow detention time= 885.6 min calculated for 2.076 af(100% of inflow)
Center-of-Mass det. time= 885.9 min ( 1,719.5 - 833.5 )
Volume Invert Avail.Storage Storage Description
#1 611.00' 157,044 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
611.00 15,196 0 0
612.00 18,261 16,729 16,729
614.00 21,553 39,814 56,543
616.00 25,068 46,621 103,164
618.00 28,812 53,880 157,044
Device Routing Invert Outlet Devices
#1 Primary 608.00' 36.0" x 60.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 607.70' S= 0.0050 '/' Cc= 0.900 n= 0.012
#2 Device 1 611.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.312 0.437 0.562 0.686 0.811 0.936
#3 Device 1 613.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 615.00' 4.00'W x 1.00' H Vert.Weir C= 0.600
#5 Device 1 616.00' 4.00'x 4.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#6 Secondary 617.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=1.32 cfs @ 14.62 hrs HW=613.92' (Free Discharge)
Lam=Culvert (Passes 1.32 cfs of 71.52 cfs potential flow)
-2=Exfiltration (Custom Controls 0.55 cfs)
-3=Orifice/Grate (Orifice Controls 0.77 cfs @ 3.93 fps)
-4=Weir ( Controls 0.00 cfs)
-5=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=611.00' (Free Discharge)
t-6=Spillway ( Controls 0.00 cfs)

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP1)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 611.00 0.00 0.00 0.00
5.00 0.00 0 611.00 0.00 0.00 0.00
10.00 0.20 340 611.02 0.01 0.01 0.00
15.00 1.22 54,661 613.91 1.32 1.32 0.00
20.00 0.55 47,592 613.58 1.05 1.05 0.00
25.00 0.00 39,945 613.21 0.58 0.58 0.00
30.00 0.00 31,762 612.79 0.41 0.41 0.00
35.00 0.00 24,772 612.43 0.37 0.37 0.00
40.00 0.00 18,563 612.10 0.32 0.32 0.00
45.00 0.00 13,288 611.81 0.25 0.25 0.00
50.00 0.00 9,407 611.58 0.18 0.18 0.00
55.00 0.00 6,616 611.42 0.13 0.13 0.00
60.00 0.00 4,631 611.30 0.09 0.09 0.00
65.00 0.00 3,230 611.21 0.06 0.06 0.00
70.00 0.00 2,247 611.15 0.05 0.05 0.00
75.00 0.00 1,560 611.10 0.03 0.03 0.00
80.00 0.00 1,082 611.07 0.02 0.02 0.00
85.00 0.00 749 611.05 0.02 0.02 0.00
90.00 0.00 519 611.03 0.01 0.01 0.00
95.00 0.00 360 611.02 0.01 0.01 0.00
100.00 0.00 249 611.02 0.01 0.01 0.00
105.00 0.00 173 611.01 0.00 0.00 0.00
110.00 0.00 120 611.01 0.00 0.00 0.00
115.00 0.00 83 611.01 0.00 0.00 0.00
120.00 0.00 57 611.00 0.00 0.00 0.00
125.00 0.00 40 611.00 0.00 0.00 0.00
130.00 0.00 28 611.00 0.00 0.00 0.00
135.00 0.00 19 611.00 0.00 0.00 0.00
140.00 0.00 13 611.00 0.00 0.00 0.00
145.00 0.00 9 611.00 0.00 0.00 0.00
150.00 0.00 6 611.00 0.00 0.00 0.00
155.00 0.00 4 611.00 0.00 0.00 0.00
160.00 0.00 3 611.00 0.00 0.00 0.00
165.00 0.00 2 611.00 0.00 0.00 0.00
170.00 0.00 1 611.00 0.00 0.00 0.00
175.00 0.00 1 611.00 0.00 0.00 0.00
180.00 0.00 1 611.00 0.00 0.00 0.00
185.00 0.00 0 611.00 0.00 0.00 0.00
190.00 0.00 0 611.00 0.00 0.00 0.00
195.00 0.00 0 611.00 0.00 0.00 0.00
200.00 0.00 0 611.00 0.00 0.00 0.00

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP1)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
611.00 0.00 0.00 0.00 616.20 22.87 22.87 0.00
611.10 0.03 0.03 0.00 616.30 28.02 28.02 0.00
611.20 0.06 0.06 0.00 616.40 33.80 33.80 0.00
611.30 0.09 0.09 0.00 616.50 40.12 40.12 0.00
611.40 0.12 0.12 0.00 616.60 46.95 46.95 0.00
611.50 0.16 0.16 0.00 616.70 54.24 54.24 0.00
611.60 0.19 0.19 0.00 616.80 61.95 61.95 0.00
611.70 0.22 0.22 0.00 616.90 70.07 70.07 0.00
611.80 0.25 0.25 0.00 617.00 78.56 78.56 0.00
611.90 0.28 0.28 0.00 617.10 88.26 87.41 0.85
612.00 0.31 0.31 0.00 617.20 96.84 94.44 2.40
612.10 0.32 0.32 0.00 617.30 99.47 95.05 4.42
612.20 0.34 0.34 0.00 617.40 102.49 95.66 6.83
612.30 0.35 0.35 0.00 617.50 105.81 96.27 9.55
612.40 0.36 0.36 0.00 617.60 109.41 96.87 12.55
612.50 0.37 0.37 0.00 617.70 113.10 97.46 15.64
612.60 0.39 0.39 0.00 617.80 116.94 98.05 18.89
612.70 0.40 0.40 0.00 617.90 121.14 98.64 22.50
612.80 0.41 0.41 0.00 618.00 125.53 99.23 26.30
612.90 0.42 0.42 0.00
613.00 0.44 0.44 0.00
613.10 0.48 0.48 0.00
613.20 0.57 0.57 0.00
613.30 0.70 0.70 0.00
613.40 0.85 0.85 0.00
613.50 0.97 0.97 0.00
613.60 1.07 1.07 0.00
613.70 1.16 1.16 0.00
613.80 1.24 1.24 0.00
613.90 1.31 1.31 0.00
614.00 1.38 1.38 0.00
614.10 1.45 1.45 0.00
614.20 1.51 1.51 0.00
614.30 1.57 1.57 0.00
614.40 1.63 1.63 0.00
614.50 1.68 1.68 0.00
614.60 1.73 1.73 0.00
614.70 1.79 1.79 0.00
614.80 1.84 1.84 0.00
614.90 1.89 1.89 0.00
615.00 1.94 1.94 0.00
615.10 2.39 2.39 0.00
615.20 3.18 3.18 0.00
615.30 4.19 4.19 0.00
615.40 5.37 5.37 0.00
615.50 6.71 6.71 0.00
615.60 8.18 8.18 0.00
615.70 9.77 9.77 0.00
615.80 11.48 11.48 0.00
615.90 13.30 13.30 0.00
616.00 15.22 15.22 0.00
616.10 18.48 18.48 0.00

2020.17-BMP1 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP1)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
611.00 15,196 0 616.20 25,442 108,215
611.10 15,503 1,535 616.30 25,630 110,768
611.20 15,809 3,101 ' 616.40 25,817 113,340
611.30 16,115 4,697 616.50 26,004 115,932
611.40 16,422 6,324 616.60 26,191 118,541
611.50 16,729 7,981 616.70 26,378 121,170
611.60 17,035 9,669 616.80 26,566 123,817
611.70 17,342 11,388 616.90 26,753 126,483
611.80 17,648 13,138 617.00 26,940 129,168
611.90 17,954 14,918 ' 617.10 27,127 131,871
612.00 18,261 16,729 617.20 27,314 134,593
612.10 18,426 18,563 , 617.30 27,502 137,334
612.20 18,590 20,414 617.40 27,689 140,093
612.30 18,755 22,281 617.50 27,876 142,872
612.40 18,919 24,165 617.60 28,063 145,668
612.50 19,084 26,065 617.70 28,250 148,484
612.60 19,249 27,981 617.80 28,438 151,319
612.70 19,413 29,914 617.90 28,625 154,172
612.80 19,578 31,864 618.00 28,812 157,044
612.90 19,742 33,830
613.00 19,907 35,813
613.10 20,072 37,811
613.20 20,236 39,827
613.30 20,401 41,859
613.40 20,565 43,907
613.50 20,730 45,972
613.60 20,895 48,053
613.70 21,059 50,151
613.80 21,224 52,265
613.90 21,388 54,395
614.00 21,553 56,543
614.10 21,729 58,707
614.20 21,905 60,888
614.30 22,080 63,087
614.40 22,256 65,304
614.50 22,432 67,539
614.60 22,608 69,791
614.70 22,783 72,060
614.80 22,959 74,347
614.90 23,135 76,652
615.00 23,311 78,974
615.10 23,486 81,314
615.20 23,662 83,672
615.30 23,838 86,046
615.40 24,013 88,439
615.50 24,189 90,849
615.60 24,365 93,277
615.70 24,541 95,722
615.80 24,716 98,185
615.90 24,892 100,665
616.00 25,068 103,164
616.10 25,255 105,680

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=18.230 ac Runoff Depth=2.28"
Flow Length=1,107' Tc=22.5 min CN=72 Runoff=42.60 cfs 3.456 af
Subcatchment 2S: (Post Developed) Runoff Area=18.230 ac Runoff Depth=3.26"
Tc=5.0 min CN=83 Runoff=107.38 cfs 4.960 af
Pond 3P: (BMP1) Peak Elev=616.16' Storage=107,246 cf Inflow=107.38 cfs 4.960 af
Primary=21.14 cfs 4.960 af Secondary=0.00 cfs 0.000 af Outflow=21.14 cfs 4.960 af
Total Runoff Area = 36.460 ac Runoff Volume = 8.416 af Average Runoff Depth = 2.77"
75.62% Pervious Area = 27.570 ac 24.38% Impervious Area = 8.890 ac

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 42.60 cfs @ 12.17 hrs, Volume= 3.456 af, Depth= 2.28"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
3.200 73 Woods, Fair, HSG C
3.600 60 Woods, Fair, HSG B
3.870 69 Pasture/grassland/range, Fair, HSG B
7.560 79 Pasture/grassland/range, Fair, HSG C
18.230 72 Weighted Average
18.230 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.7 100 0.0371 0.16 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.6 719 0.0672 1.81 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
5.2 288 0.0347 0.93 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
22.5 1,107 Total

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 2.28 0.00
2.00 0.11 0.00 0.00 106.00 5.10 2.28 0.00
4.00 0.24 0.00 0.00 108.00 5.10 2.28 0.00
6.00 0.41 0.00 0.00 110.00 5.10 2.28 0.00
8.00 0.61 0.00 0.00 112.00 5.10 2.28 0.00
10.00 0.92 0.01 0.13 114.00 5.10 2.28 0.00
12.00 3.38 1.04 24.29 116.00 5.10 2.28 0.00
14.00 4.18 1.59 2.93 118.00 5.10 2.28 0.00
16.00 4.49 1.81 1.75 120.00 5.10 2.28 0.00
18.00 4.70 1.97 1.33 122.00 5.10 2.28 0.00
20.00 4.86 2.09 0.99 124.00 5.10 2.28 0.00
22.00 4.98 2.18 0.88 126.00 5.10 2.28 0.00
24.00 5.10 2.28 0.81 128.00 5.10 2.28 0.00
26.00 5.10 2.28 0.00 130.00 5.10 2.28 0.00
28.00 5.10 2.28 0.00 132.00 5.10 2.28 0.00
30.00 5.10 2.28 0.00 134.00 5.10 2.28 0.00
32.00 5.10 2.28 0.00 136.00 5.10 2.28 0.00
34.00 5.10 2.28 0.00 138.00 5.10 2.28 0.00
36.00 5.10 2.28 0.00 140.00 5.10 2.28 0.00
38.00 5.10 2.28 0.00 142.00 5.10 2.28 0.00
40.00 5.10 2.28 0.00 144.00 5.10 2.28 0.00
42.00 5.10 2.28 0.00 146.00 5.10 2.28 0.00
44.00 5.10 2.28 0.00 148.00 5.10 2.28 0.00
46.00 5.10 2.28 0.00 150.00 5.10 2.28 0.00
48.00 5.10 2.28 0.00 152.00 5.10 2.28 0.00
50.00 5.10 2.28 0.00 154.00 5.10 2.28 0.00
52.00 5.10 2.28 0.00 156.00 5.10 2.28 0.00
54.00 5.10 2.28 0.00 158.00 5.10 2.28 0.00
56.00 5.10 2.28 0.00 160.00 5.10 2.28 0.00
58.00 5.10 2.28 0.00 162.00 5.10 2.28 0.00
60.00 5.10 2.28 0.00 164.00 5.10 2.28 0.00
62.00 5.10 2.28 0.00 166.00 5.10 2.28 0.00
64.00 5.10 2.28 0.00 168.00 5.10 2.28 0.00
66.00 5.10 2.28 0.00 170.00 5.10 2.28 0.00
68.00 5.10 2.28 0.00 172.00 5.10 2.28 0.00
70.00 5.10 2.28 0.00 174.00 5.10 2.28 0.00
72.00 5.10 2.28 0.00 176.00 5.10 2.28 0.00
74.00 5.10 2.28 0.00 178.00 5.10 2.28 0.00
76.00 5.10 2.28 0.00 180.00 5.10 2.28 0.00
78.00 5.10 2.28 0.00 182.00 5.10 2.28 0.00
80.00 5.10 2.28 0.00 184.00 5.10 2.28 0.00
82.00 5.10 2.28 0.00 186.00 5.10 2.28 0.00
84.00 5.10 2.28 0.00 188.00 5.10 2.28 0.00
86.00 5.10 2.28 0.00 190.00 5.10 2.28 0.00
88.00 5.10 2.28 0.00 192.00 5.10 2.28 0.00
90.00 5.10 2.28 0.00 194.00 5.10 2.28 0.00
92.00 5.10 2.28 0.00 196.00 5.10 2.28 0.00
94.00 5.10 2.28 0.00 198.00 5.10 2.28 0.00
96.00 5.10 2.28 0.00 200.00 5.10 2.28 0.00
98.00 5.10 2.28 0.00
100.00 5.10 2.28 0.00
102.00 5.10 2.28 0.00

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 107.38 cfs @ 11.96 hrs, Volume= 4.960 af, Depth= 3.26"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
8.890 98 Paved parking & roofs
9.340 69 50-75% Grass cover, Fair, HSG B
18.230 83 Weighted Average
9.340 Pervious Area
8.890 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.26 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.26 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.26 0.00
6.00 0.41 0.00 0.00 110.00 5.10 3.26 0.00
8.00 0.61 0.02 0.34 112.00 5.10 3.26 0.00
10.00 0.92 0.10 1.28 114.00 5.10 3.26 0.00
12.00 3.38 1.76 90.99 116.00 5.10 3.26 0.00
14.00 4.18 2.44 3.16 118.00 5.10 3.26 0.00
16.00 4.49 2.71 1.96 120.00 5.10 3.26 0.00
18.00 4.70 2.90 1.53 122.00 5.10 3.26 0.00
20.00 4.86 3.04 1.11 124.00 5.10 3.26 0.00
22.00 4.98 3.16 1.02 126.00 5.10 3.26 0.00
24.00 5.10 3.26 0.94 128.00 5.10 3.26 0.00
26.00 5.10 3.26 0.00 130.00 5.10 3.26 0.00
28.00 5.10 3.26 0.00 132.00 5.10 3.26 0.00
30.00 5.10 3.26 0.00 134.00 5.10 3.26 0.00
32.00 5.10 3.26 0.00 136.00 5.10 3.26 0.00
34.00 5.10 3.26 0.00 138.00 5.10 3.26 0.00
36.00 5.10 3.26 0.00 140.00 5.10 3.26 0.00
38.00 5.10 3.26 0.00 142.00 5.10 3.26 0.00
40.00 5.10 3.26 0.00 144.00 5.10 3.26 0.00
42.00 5.10 3.26 0.00 146.00 5.10 3.26 0.00
44.00 5.10 3.26 0.00 148.00 5.10 3.26 0.00
46.00 5.10 3.26 0.00 150.00 5.10 3.26 0.00
48.00 5.10 3.26 0.00 152.00 5.10 3.26 0.00
50.00 5.10 3.26 0.00 154.00 5.10 3.26 0.00
52.00 5.10 3.26 0.00 156.00 5.10 3.26 0.00
54.00 5.10 3.26 0.00 158.00 5.10 3.26 0.00
56.00 5.10 3.26 0.00 160.00 5.10 3.26 0.00
58.00 5.10 3.26 0.00 162.00 5.10 3.26 0.00
60.00 5.10 3.26 0.00 164.00 5.10 3.26 0.00
62.00 5.10 3.26 0.00 166.00 5.10 3.26 0.00
64.00 5.10 3.26 0.00 168.00 5.10 3.26 0.00
66.00 5.10 3.26 0.00 170.00 5.10 3.26 0.00
68.00 5.10 3.26 0.00 172.00 5.10 3.26 0.00
70.00 5.10 3.26 0.00 174.00 5.10 3.26 0.00
72.00 5.10 3.26 0.00 176.00 5.10 3.26 0.00
74.00 5.10 3.26 0.00 178.00 5.10 3.26 0.00
76.00 5.10 3.26 0.00 180.00 5.10 3.26 0.00
78.00 5.10 3.26 0.00 182.00 5.10 3.26 0.00
80.00 5.10 3.26 0.00 184.00 5.10 3.26 0.00
82.00 5.10 3.26 0.00 186.00 5.10 3.26 0.00
84.00 5.10 3.26 0.00 188.00 5.10 3.26 0.00
86.00 5.10 3.26 0.00 190.00 5.10 3.26 0.00
88.00 5.10 3.26 0.00 192.00 5.10 3.26 0.00
90.00 5.10 3.26 0.00 194.00 5.10 3.26 0.00
92.00 5.10 3.26 0.00 196.00 5.10 3.26 0.00
94.00 5.10 3.26 0.00 198.00 5.10 3.26 0.00
96.00 5.10 3.26 0.00 200.00 5.10 3.26 0.00
98.00 5.10 3.26 0.00
100.00 5.10 3.26 0.00
102.00 5.10 3.26 0.00

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP1)
Inflow Area = 18.230 ac, Inflow Depth = 3.26" for 10-yr Concord event
Inflow = 107.38 cfs @ 11.96 hrs, Volume= 4.960 af
Outflow = 21.14 cfs @ 12.11 hrs, Volume= 4.960 af, Atten= 80%, Lag= 8.9 min
Primary = 21.14 cfs @ 12.11 hrs, Volume= 4.960 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 616.16' @ 12.11 hrs Surf.Area= 25,371 sf Storage= 107,246 cf
Plug-Flow detention time= 554.6 min calculated for 4.959 af(100% of inflow)
Center-of-Mass det. time= 554.9 min ( 1,363.6 - 808.6 )
Volume Invert Avail.Storage Storage Description
#1 611.00' 157,044 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
611.00 15,196 0 0
612.00 18,261 16,729 16,729
614.00 21,553 39,814 56,543
616.00 25,068 46,621 103,164
618.00 28,812 53,880 157,044
Device Routing Invert Outlet Devices
#1 Primary 608.00' 36.0" x 60.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 607.70' S= 0.0050 '/' Cc= 0.900 n= 0.012
#2 Device 1 611.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.312 0.437 0.562 0.686 0.811 0.936
#3 Device 1 613.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 615.00' 4.00'W x 1.00' H Vert.Weir C= 0.600
#5 Device 1 616.00' 4.00'x 4.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#6 Secondary 617.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=21.09 cfs @ 12.11 hrs HW=616.16' (Free Discharge)
Lam=Culvert (Passes 21.09 cfs of 87.85 cfs potential flow)
-2=Exfiltration (Custom Controls 0.83 cfs)
-3=Orifice/Grate (Orifice Controls 1.61 cfs @ 8.22 fps)
-4=Weir (Orifice Controls 15.24 cfs @ 3.81 fps)
-5=Top of Riser (Weir Controls 3.40 cfs @ 1.32 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=611.00' (Free Discharge)
t-6=Spillway ( Controls 0.00 cfs)

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP1)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 611.00 0.00 0.00 0.00
5.00 0.00 0 611.00 0.00 0.00 0.00
10.00 1.28 5,959 611.38 0.12 0.12 0.00
15.00 2.53 83,493 615.19 3.12 3.12 0.00
20.00 1.11 74,582 614.81 1.84 1.84 0.00
25.00 0.00 59,180 614.12 1.46 1.46 0.00
30.00 0.00 40,365 613.23 0.61 0.61 0.00
35.00 0.00 32,053 612.81 0.41 0.41 0.00
40.00 0.00 25,031 612.45 0.37 0.37 0.00
45.00 0.00 18,793 612.11 0.33 0.33 0.00
50.00 0.00 13,467 611.82 0.26 0.26 0.00
55.00 0.00 9,536 611.59 0.18 0.18 0.00
60.00 0.00 6,709 611.42 0.13 0.13 0.00
65.00 0.00 4,696 611.30 0.09 0.09 0.00
70.00 0.00 3,276 611.21 0.07 0.07 0.00
75.00 0.00 2,279 611.15 0.05 0.05 0.00
80.00 0.00 1,582 611.10 0.03 0.03 0.00
85.00 0.00 1,097 611.07 0.02 0.02 0.00
90.00 0.00 760 611.05 0.02 0.02 0.00
95.00 0.00 527 611.03 0.01 0.01 0.00
100.00 0.00 365 611.02 0.01 0.01 0.00
105.00 0.00 253 611.02 0.01 0.01 0.00
110.00 0.00 175 611.01 0.00 0.00 0.00
115.00 0.00 121 611.01 0.00 0.00 0.00
120.00 0.00 84 611.01 0.00 0.00 0.00
125.00 0.00 58 611.00 0.00 0.00 0.00
130.00 0.00 40 611.00 0.00 0.00 0.00
135.00 0.00 28 611.00 0.00 0.00 0.00
140.00 0.00 19 611.00 0.00 0.00 0.00
145.00 0.00 13 611.00 0.00 0.00 0.00
150.00 0.00 9 611.00 0.00 0.00 0.00
155.00 0.00 6 611.00 0.00 0.00 0.00
160.00 0.00 4 611.00 0.00 0.00 0.00
165.00 0.00 3 611.00 0.00 0.00 0.00
170.00 0.00 2 611.00 0.00 0.00 0.00
175.00 0.00 1 611.00 0.00 0.00 0.00
180.00 0.00 1 611.00 0.00 0.00 0.00
185.00 0.00 1 611.00 0.00 0.00 0.00
190.00 0.00 0 611.00 0.00 0.00 0.00
195.00 0.00 0 611.00 0.00 0.00 0.00
200.00 0.00 0 611.00 0.00 0.00 0.00

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP1)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
611.00 0.00 0.00 0.00 616.20 22.87 22.87 0.00
611.10 0.03 0.03 0.00 616.30 28.02 28.02 0.00
611.20 0.06 0.06 0.00 616.40 33.80 33.80 0.00
611.30 0.09 0.09 0.00 616.50 40.12 40.12 0.00
611.40 0.12 0.12 0.00 616.60 46.95 46.95 0.00
611.50 0.16 0.16 0.00 616.70 54.24 54.24 0.00
611.60 0.19 0.19 0.00 616.80 61.95 61.95 0.00
611.70 0.22 0.22 0.00 616.90 70.07 70.07 0.00
611.80 0.25 0.25 0.00 617.00 78.56 78.56 0.00
611.90 0.28 0.28 0.00 617.10 88.26 87.41 0.85
612.00 0.31 0.31 0.00 617.20 96.84 94.44 2.40
612.10 0.32 0.32 0.00 617.30 99.47 95.05 4.42
612.20 0.34 0.34 0.00 617.40 102.49 95.66 6.83
612.30 0.35 0.35 0.00 617.50 105.81 96.27 9.55
612.40 0.36 0.36 0.00 617.60 109.41 96.87 12.55
612.50 0.37 0.37 0.00 617.70 113.10 97.46 15.64
612.60 0.39 0.39 0.00 617.80 116.94 98.05 18.89
612.70 0.40 0.40 0.00 617.90 121.14 98.64 22.50
612.80 0.41 0.41 0.00 618.00 125.53 99.23 26.30
612.90 0.42 0.42 0.00
613.00 0.44 0.44 0.00
613.10 0.48 0.48 0.00
613.20 0.57 0.57 0.00
613.30 0.70 0.70 0.00
613.40 0.85 0.85 0.00
613.50 0.97 0.97 0.00
613.60 1.07 1.07 0.00
613.70 1.16 1.16 0.00
613.80 1.24 1.24 0.00
613.90 1.31 1.31 0.00
614.00 1.38 1.38 0.00
614.10 1.45 1.45 0.00
614.20 1.51 1.51 0.00
614.30 1.57 1.57 0.00
614.40 1.63 1.63 0.00
614.50 1.68 1.68 0.00
614.60 1.73 1.73 0.00
614.70 1.79 1.79 0.00
614.80 1.84 1.84 0.00
614.90 1.89 1.89 0.00
615.00 1.94 1.94 0.00
615.10 2.39 2.39 0.00
615.20 3.18 3.18 0.00
615.30 4.19 4.19 0.00
615.40 5.37 5.37 0.00
615.50 6.71 6.71 0.00
615.60 8.18 8.18 0.00
615.70 9.77 9.77 0.00
615.80 11.48 11.48 0.00
615.90 13.30 13.30 0.00
616.00 15.22 15.22 0.00
616.10 18.48 18.48 0.00

2020.17-BMP1 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP1)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
611.00 15,196 0 616.20 25,442 108,215
611.10 15,503 1,535 616.30 25,630 110,768
611.20 15,809 3,101 ' 616.40 25,817 113,340
611.30 16,115 4,697 616.50 26,004 115,932
611.40 16,422 6,324 616.60 26,191 118,541
611.50 16,729 7,981 616.70 26,378 121,170
611.60 17,035 9,669 616.80 26,566 123,817
611.70 17,342 11,388 616.90 26,753 126,483
611.80 17,648 13,138 617.00 26,940 129,168
611.90 17,954 14,918 ' 617.10 27,127 131,871
612.00 18,261 16,729 617.20 27,314 134,593
612.10 18,426 18,563 , 617.30 27,502 137,334
612.20 18,590 20,414 617.40 27,689 140,093
612.30 18,755 22,281 617.50 27,876 142,872
612.40 18,919 24,165 617.60 28,063 145,668
612.50 19,084 26,065 617.70 28,250 148,484
612.60 19,249 27,981 617.80 28,438 151,319
612.70 19,413 29,914 617.90 28,625 154,172
612.80 19,578 31,864 618.00 28,812 157,044
612.90 19,742 33,830
613.00 19,907 35,813
613.10 20,072 37,811
613.20 20,236 39,827
613.30 20,401 41,859
613.40 20,565 43,907
613.50 20,730 45,972
613.60 20,895 48,053
613.70 21,059 50,151
613.80 21,224 52,265
613.90 21,388 54,395
614.00 21,553 56,543
614.10 21,729 58,707
614.20 21,905 60,888
614.30 22,080 63,087
614.40 22,256 65,304
614.50 22,432 67,539
614.60 22,608 69,791
614.70 22,783 72,060
614.80 22,959 74,347
614.90 23,135 76,652
615.00 23,311 78,974
615.10 23,486 81,314
615.20 23,662 83,672
615.30 23,838 86,046
615.40 24,013 88,439
615.50 24,189 90,849
615.60 24,365 93,277
615.70 24,541 95,722
615.80 24,716 98,185
615.90 24,892 100,665
616.00 25,068 103,164
616.10 25,255 105,680

2020.17-BMP1 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=18.230 ac Runoff Depth=2.99"
Flow Length=1,107' Tc=22.5 min CN=72 Runoff=56.44 cfs 4.547 af
Subcatchment 2S: (Post Developed) Runoff Area=18.230 ac Runoff Depth=4.09"
Tc=5.0 min CN=83 Runoff=132.94 cfs 6.215 af
Pond 3P: (BMP1) Peak Elev=616.78' Storage=123,332 cf Inflow=132.94 cfs 6.215 af
Primary=60.54 cfs 6.215 af Secondary=0.00 cfs 0.000 af Outflow=60.54 cfs 6.215 af
Total Runoff Area = 36.460 ac Runoff Volume = 10.763 af Average Runoff Depth = 3.54"
75.62% Pervious Area = 27.570 ac 24.38% Impervious Area = 8.890 ac

2020.17-BMP1 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 56.44 cfs @ 12.16 hrs, Volume= 4.547 af, Depth= 2.99"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
3.200 73 Woods, Fair, HSG C
3.600 60 Woods, Fair, HSG B
3.870 69 Pasture/grassland/range, Fair, HSG B
7.560 79 Pasture/grassland/range, Fair, HSG C
18.230 72 Weighted Average
18.230 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.7 100 0.0371 0.16 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.6 719 0.0672 1.81 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
5.2 288 0.0347 0.93 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
22.5 1,107 Total

2020.17-BMP1 Type /I 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 2.99 0.00
2.00 0.13 0.00 0.00 106.00 6.00 2.99 0.00
4.00 0.29 0.00 0.00 108.00 6.00 2.99 0.00
6.00 0.48 0.00 0.00 110.00 6.00 2.99 0.00
8.00 0.72 0.00 0.00 112.00 6.00 2.99 0.00
10.00 1.09 0.02 0.42 114.00 6.00 2.99 0.00
12.00 3.98 1.44 33.33 116.00 6.00 2.99 0.00
14.00 4.92 2.14 3.70 118.00 6.00 2.99 0.00
16.00 5.28 2.42 2.19 120.00 6.00 2.99 0.00
18.00 5.53 2.61 1.65 122.00 6.00 2.99 0.00
20.00 5.71 2.76 1.23 124.00 6.00 2.99 0.00
22.00 5.86 2.88 1.09 126.00 6.00 2.99 0.00
24.00 6.00 2.99 1.01 128.00 6.00 2.99 0.00
26.00 6.00 2.99 0.00 130.00 6.00 2.99 0.00
28.00 6.00 2.99 0.00 132.00 6.00 2.99 0.00
30.00 6.00 2.99 0.00 134.00 6.00 2.99 0.00
32.00 6.00 2.99 0.00 136.00 6.00 2.99 0.00
34.00 6.00 2.99 0.00 138.00 6.00 2.99 0.00
36.00 6.00 2.99 0.00 140.00 6.00 2.99 0.00
38.00 6.00 2.99 0.00 142.00 6.00 2.99 0.00
40.00 6.00 2.99 0.00 144.00 6.00 2.99 0.00
42.00 6.00 2.99 0.00 146.00 6.00 2.99 0.00
44.00 6.00 2.99 0.00 148.00 6.00 2.99 0.00
46.00 6.00 2.99 0.00 150.00 6.00 2.99 0.00
48.00 6.00 2.99 0.00 152.00 6.00 2.99 0.00
50.00 6.00 2.99 0.00 154.00 6.00 2.99 0.00
52.00 6.00 2.99 0.00 156.00 6.00 2.99 0.00
54.00 6.00 2.99 0.00 158.00 6.00 2.99 0.00
56.00 6.00 2.99 0.00 160.00 6.00 2.99 0.00
58.00 6.00 2.99 0.00 162.00 6.00 2.99 0.00
60.00 6.00 2.99 0.00 164.00 6.00 2.99 0.00
62.00 6.00 2.99 0.00 166.00 6.00 2.99 0.00
64.00 6.00 2.99 0.00 168.00 6.00 2.99 0.00
66.00 6.00 2.99 0.00 170.00 6.00 2.99 0.00
68.00 6.00 2.99 0.00 172.00 6.00 2.99 0.00
70.00 6.00 2.99 0.00 174.00 6.00 2.99 0.00
72.00 6.00 2.99 0.00 176.00 6.00 2.99 0.00
74.00 6.00 2.99 0.00 178.00 6.00 2.99 0.00
76.00 6.00 2.99 0.00 180.00 6.00 2.99 0.00
78.00 6.00 2.99 0.00 182.00 6.00 2.99 0.00
80.00 6.00 2.99 0.00 184.00 6.00 2.99 0.00
82.00 6.00 2.99 0.00 186.00 6.00 2.99 0.00
84.00 6.00 2.99 0.00 188.00 6.00 2.99 0.00
86.00 6.00 2.99 0.00 190.00 6.00 2.99 0.00
88.00 6.00 2.99 0.00 192.00 6.00 2.99 0.00
90.00 6.00 2.99 0.00 194.00 6.00 2.99 0.00
92.00 6.00 2.99 0.00 196.00 6.00 2.99 0.00
94.00 6.00 2.99 0.00 198.00 6.00 2.99 0.00
96.00 6.00 2.99 0.00 200.00 6.00 2.99 0.00
98.00 6.00 2.99 0.00
100.00 6.00 2.99 0.00
102.00 6.00 2.99 0.00

2020.17-BMP1 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 132.94 cfs @ 11.96 hrs, Volume= 6.215 af, Depth= 4.09"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
8.890 98 Paved parking & roofs
9.340 69 50-75% Grass cover, Fair, HSG B
18.230 83 Weighted Average
9.340 Pervious Area
8.890 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP1 Type /I 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 4.09 0.00
2.00 0.13 0.00 0.00 106.00 6.00 4.09 0.00
4.00 0.29 0.00 0.00 108.00 6.00 4.09 0.00
6.00 0.48 0.00 0.11 110.00 6.00 4.09 0.00
8.00 0.72 0.04 0.58 112.00 6.00 4.09 0.00
10.00 1.09 0.17 1.83 114.00 6.00 4.09 0.00
12.00 3.98 2.27 112.11 116.00 6.00 4.09 0.00
14.00 4.92 3.10 3.83 118.00 6.00 4.09 0.00
16.00 5.28 3.43 2.37 120.00 6.00 4.09 0.00
18.00 5.53 3.65 1.84 122.00 6.00 4.09 0.00
20.00 5.71 3.82 1.34 124.00 6.00 4.09 0.00
22.00 5.86 3.96 1.23 126.00 6.00 4.09 0.00
24.00 6.00 4.09 1.13 128.00 6.00 4.09 0.00
26.00 6.00 4.09 0.00 130.00 6.00 4.09 0.00
28.00 6.00 4.09 0.00 132.00 6.00 4.09 0.00
30.00 6.00 4.09 0.00 134.00 6.00 4.09 0.00
32.00 6.00 4.09 0.00 136.00 6.00 4.09 0.00
34.00 6.00 4.09 0.00 138.00 6.00 4.09 0.00
36.00 6.00 4.09 0.00 140.00 6.00 4.09 0.00
38.00 6.00 4.09 0.00 142.00 6.00 4.09 0.00
40.00 6.00 4.09 0.00 144.00 6.00 4.09 0.00
42.00 6.00 4.09 0.00 146.00 6.00 4.09 0.00
44.00 6.00 4.09 0.00 148.00 6.00 4.09 0.00
46.00 6.00 4.09 0.00 150.00 6.00 4.09 0.00
48.00 6.00 4.09 0.00 152.00 6.00 4.09 0.00
50.00 6.00 4.09 0.00 154.00 6.00 4.09 0.00
52.00 6.00 4.09 0.00 156.00 6.00 4.09 0.00
54.00 6.00 4.09 0.00 158.00 6.00 4.09 0.00
56.00 6.00 4.09 0.00 160.00 6.00 4.09 0.00
58.00 6.00 4.09 0.00 162.00 6.00 4.09 0.00
60.00 6.00 4.09 0.00 164.00 6.00 4.09 0.00
62.00 6.00 4.09 0.00 166.00 6.00 4.09 0.00
64.00 6.00 4.09 0.00 168.00 6.00 4.09 0.00
66.00 6.00 4.09 0.00 170.00 6.00 4.09 0.00
68.00 6.00 4.09 0.00 172.00 6.00 4.09 0.00
70.00 6.00 4.09 0.00 174.00 6.00 4.09 0.00
72.00 6.00 4.09 0.00 176.00 6.00 4.09 0.00
74.00 6.00 4.09 0.00 178.00 6.00 4.09 0.00
76.00 6.00 4.09 0.00 180.00 6.00 4.09 0.00
78.00 6.00 4.09 0.00 182.00 6.00 4.09 0.00
80.00 6.00 4.09 0.00 184.00 6.00 4.09 0.00
82.00 6.00 4.09 0.00 186.00 6.00 4.09 0.00
84.00 6.00 4.09 0.00 188.00 6.00 4.09 0.00
86.00 6.00 4.09 0.00 190.00 6.00 4.09 0.00
88.00 6.00 4.09 0.00 192.00 6.00 4.09 0.00
90.00 6.00 4.09 0.00 194.00 6.00 4.09 0.00
92.00 6.00 4.09 0.00 196.00 6.00 4.09 0.00
94.00 6.00 4.09 0.00 198.00 6.00 4.09 0.00
96.00 6.00 4.09 0.00 200.00 6.00 4.09 0.00
98.00 6.00 4.09 0.00
100.00 6.00 4.09 0.00
102.00 6.00 4.09 0.00

2020.17-BMP1 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP1)
Inflow Area = 18.230 ac, Inflow Depth = 4.09" for 25-yr Concord event
Inflow = 132.94 cfs @ 11.96 hrs, Volume= 6.215 af
Outflow = 60.54 cfs @ 12.05 hrs, Volume= 6.215 af, Atten= 54%, Lag= 5.4 min
Primary = 60.54 cfs @ 12.05 hrs, Volume= 6.215 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 616.78' @ 12.05 hrs Surf.Area= 26,531 sf Storage= 123,332 cf
Plug-Flow detention time= 466.3 min calculated for 6.215 af(100% of inflow)
Center-of-Mass det. time= 466.2 min ( 1,268.5 - 802.2 )
Volume Invert Avail.Storage Storage Description
#1 611.00' 157,044 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
611.00 15,196 0 0
612.00 18,261 16,729 16,729
614.00 21,553 39,814 56,543
616.00 25,068 46,621 103,164
618.00 28,812 53,880 157,044
Device Routing Invert Outlet Devices
#1 Primary 608.00' 36.0" x 60.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 607.70' S= 0.0050 '/' Cc= 0.900 n= 0.012
#2 Device 1 611.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.312 0.437 0.562 0.686 0.811 0.936
#3 Device 1 613.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 615.00' 4.00'W x 1.00' H Vert.Weir C= 0.600
#5 Device 1 616.00' 4.00'x 4.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#6 Secondary 617.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=60.44 cfs @ 12.05 hrs HW=616.78' (Free Discharge)
Lam=Culvert (Passes 60.44 cfs of 91.84 cfs potential flow)
-2=Exfiltration (Custom Controls 0.91 cfs)
-3=Orifice/Grate (Orifice Controls 1.78 cfs @ 9.05 fps)
-4=Weir (Orifice Controls 21.66 cfs @ 5.41 fps)
-5=Top of Riser (Weir Controls 36.10 cfs @ 2.89 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=611.00' (Free Discharge)
t-6=Spillway ( Controls 0.00 cfs)

2020.17-BMP1 Type /I 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP1)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 611.00 0.00 0.00 0.00
5.00 0.00 0 611.00 0.00 0.00 0.00
10.00 1.83 9,674 611.60 0.19 0.19 0.00
15.00 3.06 84,871 615.25 3.67 3.67 0.00
20.00 1.34 77,440 614.93 1.90 1.90 0.00
25.00 0.00 63,401 614.31 1.58 1.58 0.00
30.00 0.00 42,212 613.32 0.73 0.73 0.00
35.00 0.00 33,213 612.87 0.42 0.42 0.00
40.00 0.00 26,063 612.50 0.37 0.37 0.00
45.00 0.00 19,708 612.16 0.33 0.33 0.00
50.00 0.00 14,195 611.86 0.27 0.27 0.00
55.00 0.00 10,063 611.62 0.19 0.19 0.00
60.00 0.00 7,086 611.45 0.14 0.14 0.00
65.00 0.00 4,964 611.32 0.10 0.10 0.00
70.00 0.00 3,464 611.22 0.07 0.07 0.00
75.00 0.00 2,411 611.16 0.05 0.05 0.00
80.00 0.00 1,674 611.11 0.03 0.03 0.00
85.00 0.00 1,161 611.08 0.02 0.02 0.00
90.00 0.00 805 611.05 0.02 0.02 0.00
95.00 0.00 557 611.04 0.01 0.01 0.00
100.00 0.00 386 611.03 0.01 0.01 0.00
105.00 0.00 268 611.02 0.01 0.01 0.00
110.00 0.00 185 611.01 0.00 0.00 0.00
115.00 0.00 128 611.01 0.00 0.00 0.00
120.00 0.00 89 611.01 0.00 0.00 0.00
125.00 0.00 62 611.00 0.00 0.00 0.00
130.00 0.00 43 611.00 0.00 0.00 0.00
135.00 0.00 30 611.00 0.00 0.00 0.00
140.00 0.00 21 611.00 0.00 0.00 0.00
145.00 0.00 14 611.00 0.00 0.00 0.00
150.00 0.00 10 611.00 0.00 0.00 0.00
155.00 0.00 7 611.00 0.00 0.00 0.00
160.00 0.00 5 611.00 0.00 0.00 0.00
165.00 0.00 3 611.00 0.00 0.00 0.00
170.00 0.00 2 611.00 0.00 0.00 0.00
175.00 0.00 2 611.00 0.00 0.00 0.00
180.00 0.00 1 611.00 0.00 0.00 0.00
185.00 0.00 1 611.00 0.00 0.00 0.00
190.00 0.00 1 611.00 0.00 0.00 0.00
195.00 0.00 0 611.00 0.00 0.00 0.00
200.00 0.00 0 611.00 0.00 0.00 0.00

2020.17-BMP1 Type /I 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP1)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
611.00 0.00 0.00 0.00 616.20 22.87 22.87 0.00
611.10 0.03 0.03 0.00 616.30 28.02 28.02 0.00
611.20 0.06 0.06 0.00 616.40 33.80 33.80 0.00
611.30 0.09 0.09 0.00 616.50 40.12 40.12 0.00
611.40 0.12 0.12 0.00 616.60 46.95 46.95 0.00
611.50 0.16 0.16 0.00 616.70 54.24 54.24 0.00
611.60 0.19 0.19 0.00 616.80 61.95 61.95 0.00
611.70 0.22 0.22 0.00 616.90 70.07 70.07 0.00
611.80 0.25 0.25 0.00 617.00 78.56 78.56 0.00
611.90 0.28 0.28 0.00 617.10 88.26 87.41 0.85
612.00 0.31 0.31 0.00 617.20 96.84 94.44 2.40
612.10 0.32 0.32 0.00 617.30 99.47 95.05 4.42
612.20 0.34 0.34 0.00 617.40 102.49 95.66 6.83
612.30 0.35 0.35 0.00 617.50 105.81 96.27 9.55
612.40 0.36 0.36 0.00 617.60 109.41 96.87 12.55
612.50 0.37 0.37 0.00 617.70 113.10 97.46 15.64
612.60 0.39 0.39 0.00 617.80 116.94 98.05 18.89
612.70 0.40 0.40 0.00 617.90 121.14 98.64 22.50
612.80 0.41 0.41 0.00 618.00 125.53 99.23 26.30
612.90 0.42 0.42 0.00
613.00 0.44 0.44 0.00
613.10 0.48 0.48 0.00
613.20 0.57 0.57 0.00
613.30 0.70 0.70 0.00
613.40 0.85 0.85 0.00
613.50 0.97 0.97 0.00
613.60 1.07 1.07 0.00
613.70 1.16 1.16 0.00
613.80 1.24 1.24 0.00
613.90 1.31 1.31 0.00
614.00 1.38 1.38 0.00
614.10 1.45 1.45 0.00
614.20 1.51 1.51 0.00
614.30 1.57 1.57 0.00
614.40 1.63 1.63 0.00
614.50 1.68 1.68 0.00
614.60 1.73 1.73 0.00
614.70 1.79 1.79 0.00
614.80 1.84 1.84 0.00
614.90 1.89 1.89 0.00
615.00 1.94 1.94 0.00
615.10 2.39 2.39 0.00
615.20 3.18 3.18 0.00
615.30 4.19 4.19 0.00
615.40 5.37 5.37 0.00
615.50 6.71 6.71 0.00
615.60 8.18 8.18 0.00
615.70 9.77 9.77 0.00
615.80 11.48 11.48 0.00
615.90 13.30 13.30 0.00
616.00 15.22 15.22 0.00
616.10 18.48 18.48 0.00

2020.17-BMP1 Type /I 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP1)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
611.00 15,196 0 616.20 25,442 108,215
611.10 15,503 1,535 616.30 25,630 110,768
611.20 15,809 3,101 ' 616.40 25,817 113,340
611.30 16,115 4,697 616.50 26,004 115,932
611.40 16,422 6,324 616.60 26,191 118,541
611.50 16,729 7,981 616.70 26,378 121,170
611.60 17,035 9,669 616.80 26,566 123,817
611.70 17,342 11,388 616.90 26,753 126,483
611.80 17,648 13,138 617.00 26,940 129,168
611.90 17,954 14,918 ' 617.10 27,127 131,871
612.00 18,261 16,729 617.20 27,314 134,593
612.10 18,426 18,563 , 617.30 27,502 137,334
612.20 18,590 20,414 617.40 27,689 140,093
612.30 18,755 22,281 617.50 27,876 142,872
612.40 18,919 24,165 617.60 28,063 145,668
612.50 19,084 26,065 617.70 28,250 148,484
612.60 19,249 27,981 617.80 28,438 151,319
612.70 19,413 29,914 617.90 28,625 154,172
612.80 19,578 31,864 618.00 28,812 157,044
612.90 19,742 33,830
613.00 19,907 35,813
613.10 20,072 37,811
613.20 20,236 39,827
613.30 20,401 41,859
613.40 20,565 43,907
613.50 20,730 45,972
613.60 20,895 48,053
613.70 21,059 50,151
613.80 21,224 52,265
613.90 21,388 54,395
614.00 21,553 56,543
614.10 21,729 58,707
614.20 21,905 60,888
614.30 22,080 63,087
614.40 22,256 65,304
614.50 22,432 67,539
614.60 22,608 69,791
614.70 22,783 72,060
614.80 22,959 74,347
614.90 23,135 76,652
615.00 23,311 78,974
615.10 23,486 81,314
615.20 23,662 83,672
615.30 23,838 86,046
615.40 24,013 88,439
615.50 24,189 90,849
615.60 24,365 93,277
615.70 24,541 95,722
615.80 24,716 98,185
615.90 24,892 100,665
616.00 25,068 103,164
616.10 25,255 105,680

2020.17-BMP1 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=18.230 ac Runoff Depth=3.66"
Flow Length=1,107' Tc=22.5 min CN=72 Runoff=69.25 cfs 5.559 af
Subcatchment 2S: (Post Developed) Runoff Area=18.230 ac Runoff Depth=4.84"
Tc=5.0 min CN=83 Runoff=155.68 cfs 7.352 af
Pond 3P: (BMP1) Peak Elev=617.19' Storage=134,290 cf Inflow=155.68 cfs 7.352 af
Primary=93.61 cfs 7.341 af Secondary=2.23 cfs 0.011 af Outflow=95.84 cfs 7.352 af
Total Runoff Area = 36.460 ac Runoff Volume = 12.911 af Average Runoff Depth =4.25"
75.62% Pervious Area = 27.570 ac 24.38% Impervious Area = 8.890 ac

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 69.25 cfs @ 12.15 hrs, Volume= 5.559 af, Depth= 3.66"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
3.200 73 Woods, Fair, HSG C
3.600 60 Woods, Fair, HSG B
3.870 69 Pasture/grassland/range, Fair, HSG B
7.560 79 Pasture/grassland/range, Fair, HSG C
18.230 72 Weighted Average
18.230 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.7 100 0.0371 0.16 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.6 719 0.0672 1.81 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
5.2 288 0.0347 0.93 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
22.5 1,107 Total

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 3.66 0.00
2.00 0.15 0.00 0.00 106.00 6.80 3.66 0.00
4.00 0.33 0.00 0.00 108.00 6.80 3.66 0.00
6.00 0.54 0.00 0.00 110.00 6.80 3.66 0.00
8.00 0.82 0.00 0.00 112.00 6.80 3.66 0.00
10.00 1.23 0.05 0.72 114.00 6.80 3.66 0.00
12.00 4.51 1.83 41.74 116.00 6.80 3.66 0.00
14.00 5.58 2.65 4.38 118.00 6.80 3.66 0.00
16.00 5.98 2.98 2.59 120.00 6.80 3.66 0.00
18.00 6.26 3.21 1.95 122.00 6.80 3.66 0.00
20.00 6.47 3.38 1.45 124.00 6.80 3.66 0.00
22.00 6.64 3.53 1.28 126.00 6.80 3.66 0.00
24.00 6.80 3.66 1.18 128.00 6.80 3.66 0.00
26.00 6.80 3.66 0.00 130.00 6.80 3.66 0.00
28.00 6.80 3.66 0.00 132.00 6.80 3.66 0.00
30.00 6.80 3.66 0.00 134.00 6.80 3.66 0.00
32.00 6.80 3.66 0.00 136.00 6.80 3.66 0.00
34.00 6.80 3.66 0.00 138.00 6.80 3.66 0.00
36.00 6.80 3.66 0.00 140.00 6.80 3.66 0.00
38.00 6.80 3.66 0.00 142.00 6.80 3.66 0.00
40.00 6.80 3.66 0.00 144.00 6.80 3.66 0.00
42.00 6.80 3.66 0.00 146.00 6.80 3.66 0.00
44.00 6.80 3.66 0.00 148.00 6.80 3.66 0.00
46.00 6.80 3.66 0.00 150.00 6.80 3.66 0.00
48.00 6.80 3.66 0.00 152.00 6.80 3.66 0.00
50.00 6.80 3.66 0.00 154.00 6.80 3.66 0.00
52.00 6.80 3.66 0.00 156.00 6.80 3.66 0.00
54.00 6.80 3.66 0.00 158.00 6.80 3.66 0.00
56.00 6.80 3.66 0.00 160.00 6.80 3.66 0.00
58.00 6.80 3.66 0.00 162.00 6.80 3.66 0.00
60.00 6.80 3.66 0.00 164.00 6.80 3.66 0.00
62.00 6.80 3.66 0.00 166.00 6.80 3.66 0.00
64.00 6.80 3.66 0.00 168.00 6.80 3.66 0.00
66.00 6.80 3.66 0.00 170.00 6.80 3.66 0.00
68.00 6.80 3.66 0.00 172.00 6.80 3.66 0.00
70.00 6.80 3.66 0.00 174.00 6.80 3.66 0.00
72.00 6.80 3.66 0.00 176.00 6.80 3.66 0.00
74.00 6.80 3.66 0.00 178.00 6.80 3.66 0.00
76.00 6.80 3.66 0.00 180.00 6.80 3.66 0.00
78.00 6.80 3.66 0.00 182.00 6.80 3.66 0.00
80.00 6.80 3.66 0.00 184.00 6.80 3.66 0.00
82.00 6.80 3.66 0.00 186.00 6.80 3.66 0.00
84.00 6.80 3.66 0.00 188.00 6.80 3.66 0.00
86.00 6.80 3.66 0.00 190.00 6.80 3.66 0.00
88.00 6.80 3.66 0.00 192.00 6.80 3.66 0.00
90.00 6.80 3.66 0.00 194.00 6.80 3.66 0.00
92.00 6.80 3.66 0.00 196.00 6.80 3.66 0.00
94.00 6.80 3.66 0.00 198.00 6.80 3.66 0.00
96.00 6.80 3.66 0.00 200.00 6.80 3.66 0.00
98.00 6.80 3.66 0.00
100.00 6.80 3.66 0.00
102.00 6.80 3.66 0.00

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 155.68 cfs @ 11.96 hrs, Volume= 7.352 af, Depth= 4.84"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
8.890 98 Paved parking & roofs
9.340 69 50-75% Grass cover, Fair, HSG B
18.230 83 Weighted Average
9.340 Pervious Area
8.890 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 4.84 0.00
2.00 0.15 0.00 0.00 106.00 6.80 4.84 0.00
4.00 0.33 0.00 0.00 108.00 6.80 4.84 0.00
6.00 0.54 0.01 0.25 110.00 6.80 4.84 0.00
8.00 0.82 0.07 0.81 112.00 6.80 4.84 0.00
10.00 1.23 0.24 2.34 114.00 6.80 4.84 0.00
12.00 4.51 2.73 130.87 116.00 6.80 4.84 0.00
14.00 5.58 3.70 4.43 118.00 6.80 4.84 0.00
16.00 5.98 4.08 2.73 120.00 6.80 4.84 0.00
18.00 6.26 4.34 2.12 122.00 6.80 4.84 0.00
20.00 6.47 4.53 1.54 124.00 6.80 4.84 0.00
22.00 6.64 4.69 1.41 126.00 6.80 4.84 0.00
24.00 6.80 4.84 1.30 128.00 6.80 4.84 0.00
26.00 6.80 4.84 0.00 130.00 6.80 4.84 0.00
28.00 6.80 4.84 0.00 132.00 6.80 4.84 0.00
30.00 6.80 4.84 0.00 134.00 6.80 4.84 0.00
32.00 6.80 4.84 0.00 136.00 6.80 4.84 0.00
34.00 6.80 4.84 0.00 138.00 6.80 4.84 0.00
36.00 6.80 4.84 0.00 140.00 6.80 4.84 0.00
38.00 6.80 4.84 0.00 142.00 6.80 4.84 0.00
40.00 6.80 4.84 0.00 144.00 6.80 4.84 0.00
42.00 6.80 4.84 0.00 146.00 6.80 4.84 0.00
44.00 6.80 4.84 0.00 148.00 6.80 4.84 0.00
46.00 6.80 4.84 0.00 150.00 6.80 4.84 0.00
48.00 6.80 4.84 0.00 152.00 6.80 4.84 0.00
50.00 6.80 4.84 0.00 154.00 6.80 4.84 0.00
52.00 6.80 4.84 0.00 156.00 6.80 4.84 0.00
54.00 6.80 4.84 0.00 158.00 6.80 4.84 0.00
56.00 6.80 4.84 0.00 160.00 6.80 4.84 0.00
58.00 6.80 4.84 0.00 162.00 6.80 4.84 0.00
60.00 6.80 4.84 0.00 164.00 6.80 4.84 0.00
62.00 6.80 4.84 0.00 166.00 6.80 4.84 0.00
64.00 6.80 4.84 0.00 168.00 6.80 4.84 0.00
66.00 6.80 4.84 0.00 170.00 6.80 4.84 0.00
68.00 6.80 4.84 0.00 172.00 6.80 4.84 0.00
70.00 6.80 4.84 0.00 174.00 6.80 4.84 0.00
72.00 6.80 4.84 0.00 176.00 6.80 4.84 0.00
74.00 6.80 4.84 0.00 178.00 6.80 4.84 0.00
76.00 6.80 4.84 0.00 180.00 6.80 4.84 0.00
78.00 6.80 4.84 0.00 182.00 6.80 4.84 0.00
80.00 6.80 4.84 0.00 184.00 6.80 4.84 0.00
82.00 6.80 4.84 0.00 186.00 6.80 4.84 0.00
84.00 6.80 4.84 0.00 188.00 6.80 4.84 0.00
86.00 6.80 4.84 0.00 190.00 6.80 4.84 0.00
88.00 6.80 4.84 0.00 192.00 6.80 4.84 0.00
90.00 6.80 4.84 0.00 194.00 6.80 4.84 0.00
92.00 6.80 4.84 0.00 196.00 6.80 4.84 0.00
94.00 6.80 4.84 0.00 198.00 6.80 4.84 0.00
96.00 6.80 4.84 0.00 200.00 6.80 4.84 0.00
98.00 6.80 4.84 0.00
100.00 6.80 4.84 0.00
102.00 6.80 4.84 0.00

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP1)
Inflow Area = 18.230 ac, Inflow Depth = 4.84" for 50-yr Concord event
Inflow = 155.68 cfs @ 11.96 hrs, Volume= 7.352 af
Outflow = 95.84 cfs @ 12.03 hrs, Volume= 7.352 af, Atten= 38%, Lag= 4.2 min
Primary = 93.61 cfs @ 12.03 hrs, Volume= 7.341 af
Secondary= 2.23 cfs @ 12.03 hrs, Volume= 0.011 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 617.19' @ 12.03 hrs Surf.Area= 27,294 sf Storage= 134,290 cf
Plug-Flow detention time= 409.1 min calculated for 7.351 af(100% of inflow)
Center-of-Mass det. time= 409.4 min ( 1,206.9 - 797.5 )
Volume Invert Avail.Storage Storage Description
#1 611.00' 157,044 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
611.00 15,196 0 0
612.00 18,261 16,729 16,729
614.00 21,553 39,814 56,543
616.00 25,068 46,621 103,164
618.00 28,812 53,880 157,044
Device Routing Invert Outlet Devices
#1 Primary 608.00' 36.0" x 60.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 607.70' S= 0.0050 '/' Cc= 0.900 n= 0.012
#2 Device 1 611.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.312 0.437 0.562 0.686 0.811 0.936
#3 Device 1 613.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 615.00' 4.00'W x 1.00' H Vert.Weir C= 0.600
#5 Device 1 616.00' 4.00'x 4.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#6 Secondary 617.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=94.37 cfs @ 12.03 hrs HW=617.19' (Free Discharge)
Lam=Culvert (Inlet Controls 94.37 cfs @ 13.35 fps)
-2=Exfiltration (Passes < 0.94 cfs potential flow)
-3=Orifice/Grate (Passes < 1.88 cfs potential flow)
-4=Weir (Passes < 24.93 cfs potential flow)
-5=Top of Riser (Passes < 67.72 cfs potential flow)
Secondary OutFlow Max=2.18 cfs @ 12.03 hrs HW=617.19' (Free Discharge)
t-6=Spillway (Weir Controls 2.18 cfs @ 1.16 fps)

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP1)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 611.00 0.00 0.00 0.00
5.00 0.02 4 611.00 0.00 0.00 0.00
10.00 2.34 13,484 611.82 0.26 0.26 0.00
15.00 3.53 85,980 615.30 4.17 4.17 0.00
20.00 1.54 78,996 615.00 1.94 1.94 0.00
25.00 0.00 66,551 614.46 1.66 1.66 0.00
30.00 0.00 43,736 613.39 0.84 0.84 0.00
35.00 0.00 34,037 612.91 0.43 0.43 0.00
40.00 0.00 26,797 612.54 0.38 0.38 0.00
45.00 0.00 20,360 612.20 0.34 0.34 0.00
50.00 0.00 14,727 611.89 0.28 0.28 0.00
55.00 0.00 10,449 611.65 0.20 0.20 0.00
60.00 0.00 7,362 611.46 0.14 0.14 0.00
65.00 0.00 5,160 611.33 0.10 0.10 0.00
70.00 0.00 3,602 611.23 0.07 0.07 0.00
75.00 0.00 2,507 611.16 0.05 0.05 0.00
80.00 0.00 1,742 611.11 0.04 0.04 0.00
85.00 0.00 1,208 611.08 0.02 0.02 0.00
90.00 0.00 837 611.05 0.02 0.02 0.00
95.00 0.00 580 611.04 0.01 0.01 0.00
100.00 0.00 402 611.03 0.01 0.01 0.00
105.00 0.00 278 611.02 0.01 0.01 0.00
110.00 0.00 193 611.01 0.00 0.00 0.00
115.00 0.00 134 611.01 0.00 0.00 0.00
120.00 0.00 93 611.01 0.00 0.00 0.00
125.00 0.00 64 611.00 0.00 0.00 0.00
130.00 0.00 44 611.00 0.00 0.00 0.00
135.00 0.00 31 611.00 0.00 0.00 0.00
140.00 0.00 21 611.00 0.00 0.00 0.00
145.00 0.00 15 611.00 0.00 0.00 0.00
150.00 0.00 10 611.00 0.00 0.00 0.00
155.00 0.00 7 611.00 0.00 0.00 0.00
160.00 0.00 5 611.00 0.00 0.00 0.00
165.00 0.00 3 611.00 0.00 0.00 0.00
170.00 0.00 2 611.00 0.00 0.00 0.00
175.00 0.00 2 611.00 0.00 0.00 0.00
180.00 0.00 1 611.00 0.00 0.00 0.00
185.00 0.00 1 611.00 0.00 0.00 0.00
190.00 0.00 1 611.00 0.00 0.00 0.00
195.00 0.00 0 611.00 0.00 0.00 0.00
200.00 0.00 0 611.00 0.00 0.00 0.00

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP1)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
611.00 0.00 0.00 0.00 616.20 22.87 22.87 0.00
611.10 0.03 0.03 0.00 616.30 28.02 28.02 0.00
611.20 0.06 0.06 0.00 616.40 33.80 33.80 0.00
611.30 0.09 0.09 0.00 616.50 40.12 40.12 0.00
611.40 0.12 0.12 0.00 616.60 46.95 46.95 0.00
611.50 0.16 0.16 0.00 616.70 54.24 54.24 0.00
611.60 0.19 0.19 0.00 616.80 61.95 61.95 0.00
611.70 0.22 0.22 0.00 616.90 70.07 70.07 0.00
611.80 0.25 0.25 0.00 617.00 78.56 78.56 0.00
611.90 0.28 0.28 0.00 617.10 88.26 87.41 0.85
612.00 0.31 0.31 0.00 617.20 96.84 94.44 2.40
612.10 0.32 0.32 0.00 617.30 99.47 95.05 4.42
612.20 0.34 0.34 0.00 617.40 102.49 95.66 6.83
612.30 0.35 0.35 0.00 617.50 105.81 96.27 9.55
612.40 0.36 0.36 0.00 617.60 109.41 96.87 12.55
612.50 0.37 0.37 0.00 617.70 113.10 97.46 15.64
612.60 0.39 0.39 0.00 617.80 116.94 98.05 18.89
612.70 0.40 0.40 0.00 617.90 121.14 98.64 22.50
612.80 0.41 0.41 0.00 618.00 125.53 99.23 26.30
612.90 0.42 0.42 0.00
613.00 0.44 0.44 0.00
613.10 0.48 0.48 0.00
613.20 0.57 0.57 0.00
613.30 0.70 0.70 0.00
613.40 0.85 0.85 0.00
613.50 0.97 0.97 0.00
613.60 1.07 1.07 0.00
613.70 1.16 1.16 0.00
613.80 1.24 1.24 0.00
613.90 1.31 1.31 0.00
614.00 1.38 1.38 0.00
614.10 1.45 1.45 0.00
614.20 1.51 1.51 0.00
614.30 1.57 1.57 0.00
614.40 1.63 1.63 0.00
614.50 1.68 1.68 0.00
614.60 1.73 1.73 0.00
614.70 1.79 1.79 0.00
614.80 1.84 1.84 0.00
614.90 1.89 1.89 0.00
615.00 1.94 1.94 0.00
615.10 2.39 2.39 0.00
615.20 3.18 3.18 0.00
615.30 4.19 4.19 0.00
615.40 5.37 5.37 0.00
615.50 6.71 6.71 0.00
615.60 8.18 8.18 0.00
615.70 9.77 9.77 0.00
615.80 11.48 11.48 0.00
615.90 13.30 13.30 0.00
616.00 15.22 15.22 0.00
616.10 18.48 18.48 0.00

2020.17-BMP1 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP1)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
611.00 15,196 0 616.20 25,442 108,215
611.10 15,503 1,535 616.30 25,630 110,768
611.20 15,809 3,101 ' 616.40 25,817 113,340
611.30 16,115 4,697 616.50 26,004 115,932
611.40 16,422 6,324 616.60 26,191 118,541
611.50 16,729 7,981 616.70 26,378 121,170
611.60 17,035 9,669 616.80 26,566 123,817
611.70 17,342 11,388 616.90 26,753 126,483
611.80 17,648 13,138 617.00 26,940 129,168
611.90 17,954 14,918 ' 617.10 27,127 131,871
612.00 18,261 16,729 617.20 27,314 134,593
612.10 18,426 18,563 , 617.30 27,502 137,334
612.20 18,590 20,414 617.40 27,689 140,093
612.30 18,755 22,281 617.50 27,876 142,872
612.40 18,919 24,165 617.60 28,063 145,668
612.50 19,084 26,065 617.70 28,250 148,484
612.60 19,249 27,981 617.80 28,438 151,319
612.70 19,413 29,914 617.90 28,625 154,172
612.80 19,578 31,864 618.00 28,812 157,044
612.90 19,742 33,830
613.00 19,907 35,813
613.10 20,072 37,811
613.20 20,236 39,827
613.30 20,401 41,859
613.40 20,565 43,907
613.50 20,730 45,972
613.60 20,895 48,053
613.70 21,059 50,151
613.80 21,224 52,265
613.90 21,388 54,395
614.00 21,553 56,543
614.10 21,729 58,707
614.20 21,905 60,888
614.30 22,080 63,087
614.40 22,256 65,304
614.50 22,432 67,539
614.60 22,608 69,791
614.70 22,783 72,060
614.80 22,959 74,347
614.90 23,135 76,652
615.00 23,311 78,974
615.10 23,486 81,314
615.20 23,662 83,672
615.30 23,838 86,046
615.40 24,013 88,439
615.50 24,189 90,849
615.60 24,365 93,277
615.70 24,541 95,722
615.80 24,716 98,185
615.90 24,892 100,665
616.00 25,068 103,164
616.10 25,255 105,680

SAND FILTER-2
____ H. 1. 1,71......
i
17 oamorner, maw
!4' > Apt,,;'_
� r1 ,1a.; 4ora°.r„.i...,
.,
1! I-1: [ -,
•` •�•w_f�
- '5A:�.'11
\ • /lµ:I.' . • 1
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Ilk I,
-n--,MV, '-A' iili? 1Y\;!\'u'\!'i-I\ I , U

Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 2
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 10.33 ac
Impervious area to filter forebay= 4.43 ac.
Impervious percentage= 42.86%
Rv=0.05+0.9(la) = 0.43569888
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 16338 cf (used to size Af)
WQV= 0.3751 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
632.5 15777 0 0
633 16783 8140 8140
634 18796 17789.5 25929.5
635 20418 19607 45536.5
636 22040 21229 66765.5
637 23776 22908 89673.5
638 25511 24643.5 114317
Calculate Depth for WQ Volume:
632.5 0
633.45 16338
634 25929.5
Elevation of WQ Volume= 633.45
3. Discount WQv:
0.75 x WQv 12253.34 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 68.0
Cn Post= 81.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 6.28 25.11 34.11 42.44
Post. Dev. 23.81 57.82 72.24 85.12
Routed 0.46 2.75 10.34 25.88
Peak Stage 634.32 636.11 636.41 636.81
Disch.Time 140 hours 1.2' Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
2042 SA(ft2) DV"12
2 FS SA = FS" K"T
12253 DV(FT3) where: SA =required minimum surface area of infiltration system(fK)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(ft3)
K =hydraulic conductivity of soil(in/hr)
72 T(hours) T =maximum dewatering time(72 hours)
6.Sediment Sand Sizing
12253 Design Volume(ft3)
6127 Sediment Chamber(ft3)
6127 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 340.3707 cf/hour 0.095 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
150 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 2400 holes
50%of perforations= 1200 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 9.96 cfs which is 105.3 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
7.5 Height of Riser,ft.
6 Area of Riser,s.f.
45 Volume of Riser,c.f.
2808 Weight of Water©62.4 pcf
3088.8 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
1.38 Volume of Concrete Req'd in c.y.
37.39 Volume of Concrete Req'd in c.f.
45 Volume of Concrete in Structure(cf)
-7.61 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
0.5 ft thick
2.8 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 2042 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 13614.83 0.158
2 19060.76 0.221
3 24506.69' 0.284
4 29952.62 0.347
5 35398.55 0.410
6 40844.48 0.473
7 46290.41 0.536
8 51736.34 0.599
9 57182.28 0.662
10 62628.21 0.725

(Predeveloped)
41/ 3P
(Post Developed) (BMP2)
(Subcat Reach on Drainage Diagram for 2020.17-BMP2
Prepared by{enter your company name here} 2/7/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP2
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
4.220 60 Woods, Fair, HSG B (1S)
5.900 69 50-75% Grass cover, Fair, HSG B (2S)
2.710 69 Pasture/grassland/range, Fair, HSG B (1S)
0.210 73 Woods, Fair, HSG C (1S)
3.190 79 Pasture/grassland/range, Fair, HSG C (1S)
4.430 98 Paved parking & roofs (2S)
20.660

2020.17-BMP2 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=10.330 ac Runoff Depth=0.58"
Flow Length=729' Tc=15.7 min CN=68 Runoff=6.28 cfs 0.496 af
Subcatchment 2S: (Post Developed) Runoff Area=10.330 ac Runoff Depth=1.24"
Tc=5.0 min CN=81 Runoff=23.81 cfs 1.065 af
Pond 3P: (BMP2) Peak Elev=634.32' Storage=31,937 cf Inflow=23.81 cfs 1.065 af
Primary=0.46 cfs 1.063 af Secondary=0.00 cfs 0.000 af Outflow=0.46 cfs 1.063 af
Total Runoff Area = 20.660 ac Runoff Volume = 1.561 af Average Runoff Depth = 0.91"
78.56% Pervious Area = 16.230 ac 21.44% Impervious Area = 4.430 ac

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 6.28 cfs @ 12.10 hrs, Volume= 0.496 af, Depth= 0.58"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.220 60 Woods, Fair, HSG B
0.210 73 Woods, Fair, HSG C
3.190 79 Pasture/grassland/range, Fair, HSG C
2.710 69 Pasture/grassland/range, Fair, HSG B
10.330 68 Weighted Average
10.330 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.9 100 0.0586 0.19 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.8 629 0.0482 1.54 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
15.7 729 Total

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.58 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.58 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.58 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.58 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.58 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.58 0.00
12.00 1.92 0.17 3.82 116.00 2.90 0.58 0.00
14.00 2.38 0.34 0.52 118.00 2.90 0.58 0.00
16.00 2.55 0.41 0.33 120.00 2.90 0.58 0.00
18.00 2.67 0.46 0.26 122.00 2.90 0.58 0.00
20.00 2.76 0.51 0.20 124.00 2.90 0.58 0.00
22.00 2.83 0.54 0.18 126.00 2.90 0.58 0.00
24.00 2.90 0.58 0.17 128.00 2.90 0.58 0.00
26.00 2.90 0.58 0.00 130.00 2.90 0.58 0.00
28.00 2.90 0.58 0.00 132.00 2.90 0.58 0.00
30.00 2.90 0.58 0.00 134.00 2.90 0.58 0.00
32.00 2.90 0.58 0.00 136.00 2.90 0.58 0.00
34.00 2.90 0.58 0.00 138.00 2.90 0.58 0.00
36.00 2.90 0.58 0.00 140.00 2.90 0.58 0.00
38.00 2.90 0.58 0.00 142.00 2.90 0.58 0.00
40.00 2.90 0.58 0.00 144.00 2.90 0.58 0.00
42.00 2.90 0.58 0.00 146.00 2.90 0.58 0.00
44.00 2.90 0.58 0.00 148.00 2.90 0.58 0.00
46.00 2.90 0.58 0.00 150.00 2.90 0.58 0.00
48.00 2.90 0.58 0.00 152.00 2.90 0.58 0.00
50.00 2.90 0.58 0.00 154.00 2.90 0.58 0.00
52.00 2.90 0.58 0.00 156.00 2.90 0.58 0.00
54.00 2.90 0.58 0.00 158.00 2.90 0.58 0.00
56.00 2.90 0.58 0.00 160.00 2.90 0.58 0.00
58.00 2.90 0.58 0.00 162.00 2.90 0.58 0.00
60.00 2.90 0.58 0.00 164.00 2.90 0.58 0.00
62.00 2.90 0.58 0.00 166.00 2.90 0.58 0.00
64.00 2.90 0.58 0.00 168.00 2.90 0.58 0.00
66.00 2.90 0.58 0.00 170.00 2.90 0.58 0.00
68.00 2.90 0.58 0.00 172.00 2.90 0.58 0.00
70.00 2.90 0.58 0.00 174.00 2.90 0.58 0.00
72.00 2.90 0.58 0.00 176.00 2.90 0.58 0.00
74.00 2.90 0.58 0.00 178.00 2.90 0.58 0.00
76.00 2.90 0.58 0.00 180.00 2.90 0.58 0.00
78.00 2.90 0.58 0.00 182.00 2.90 0.58 0.00
80.00 2.90 0.58 0.00 184.00 2.90 0.58 0.00
82.00 2.90 0.58 0.00 186.00 2.90 0.58 0.00
84.00 2.90 0.58 0.00 188.00 2.90 0.58 0.00
86.00 2.90 0.58 0.00 190.00 2.90 0.58 0.00
88.00 2.90 0.58 0.00 192.00 2.90 0.58 0.00
90.00 2.90 0.58 0.00 194.00 2.90 0.58 0.00
92.00 2.90 0.58 0.00 196.00 2.90 0.58 0.00
94.00 2.90 0.58 0.00 198.00 2.90 0.58 0.00
96.00 2.90 0.58 0.00 200.00 2.90 0.58 0.00
98.00 2.90 0.58 0.00
100.00 2.90 0.58 0.00
102.00 2.90 0.58 0.00

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 23.81 cfs @ 11.96 hrs, Volume= 1.065 af, Depth= 1.24"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.430 98 Paved parking & roofs
5.900 69 50-75% Grass cover, Fair, HSG B
10.330 81 Weighted Average
5.900 Pervious Area
4.430 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.24 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.24 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.24 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.24 0.00
8.00 0.35 0.00 0.00 112.00 2.90 1.24 0.00
10.00 0.52 0.00 0.05 114.00 2.90 1.24 0.00
12.00 1.92 0.56 20.79 116.00 2.90 1.24 0.00
14.00 2.38 0.86 0.81 118.00 2.90 1.24 0.00
16.00 2.55 0.98 0.51 120.00 2.90 1.24 0.00
18.00 2.67 1.07 0.40 122.00 2.90 1.24 0.00
20.00 2.76 1.13 0.30 124.00 2.90 1.24 0.00
22.00 2.83 1.19 0.27 126.00 2.90 1.24 0.00
24.00 2.90 1.24 0.25 128.00 2.90 1.24 0.00
26.00 2.90 1.24 0.00 130.00 2.90 1.24 0.00
28.00 2.90 1.24 0.00 132.00 2.90 1.24 0.00
30.00 2.90 1.24 0.00 134.00 2.90 1.24 0.00
32.00 2.90 1.24 0.00 136.00 2.90 1.24 0.00
34.00 2.90 1.24 0.00 138.00 2.90 1.24 0.00
36.00 2.90 1.24 0.00 140.00 2.90 1.24 0.00
38.00 2.90 1.24 0.00 142.00 2.90 1.24 0.00
40.00 2.90 1.24 0.00 144.00 2.90 1.24 0.00
42.00 2.90 1.24 0.00 146.00 2.90 1.24 0.00
44.00 2.90 1.24 0.00 148.00 2.90 1.24 0.00
46.00 2.90 1.24 0.00 150.00 2.90 1.24 0.00
48.00 2.90 1.24 0.00 152.00 2.90 1.24 0.00
50.00 2.90 1.24 0.00 154.00 2.90 1.24 0.00
52.00 2.90 1.24 0.00 156.00 2.90 1.24 0.00
54.00 2.90 1.24 0.00 158.00 2.90 1.24 0.00
56.00 2.90 1.24 0.00 160.00 2.90 1.24 0.00
58.00 2.90 1.24 0.00 162.00 2.90 1.24 0.00
60.00 2.90 1.24 0.00 164.00 2.90 1.24 0.00
62.00 2.90 1.24 0.00 166.00 2.90 1.24 0.00
64.00 2.90 1.24 0.00 168.00 2.90 1.24 0.00
66.00 2.90 1.24 0.00 170.00 2.90 1.24 0.00
68.00 2.90 1.24 0.00 172.00 2.90 1.24 0.00
70.00 2.90 1.24 0.00 174.00 2.90 1.24 0.00
72.00 2.90 1.24 0.00 176.00 2.90 1.24 0.00
74.00 2.90 1.24 0.00 178.00 2.90 1.24 0.00
76.00 2.90 1.24 0.00 180.00 2.90 1.24 0.00
78.00 2.90 1.24 0.00 182.00 2.90 1.24 0.00
80.00 2.90 1.24 0.00 184.00 2.90 1.24 0.00
82.00 2.90 1.24 0.00 186.00 2.90 1.24 0.00
84.00 2.90 1.24 0.00 188.00 2.90 1.24 0.00
86.00 2.90 1.24 0.00 190.00 2.90 1.24 0.00
88.00 2.90 1.24 0.00 192.00 2.90 1.24 0.00
90.00 2.90 1.24 0.00 194.00 2.90 1.24 0.00
92.00 2.90 1.24 0.00 196.00 2.90 1.24 0.00
94.00 2.90 1.24 0.00 198.00 2.90 1.24 0.00
96.00 2.90 1.24 0.00 200.00 2.90 1.24 0.00
98.00 2.90 1.24 0.00
100.00 2.90 1.24 0.00
102.00 2.90 1.24 0.00

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP2)
Inflow Area = 10.330 ac, Inflow Depth = 1.24" for 1-yr Concord event
Inflow = 23.81 cfs @ 11.96 hrs, Volume= 1.065 af
Outflow = 0.46 cfs @ 16.90 hrs, Volume= 1.063 af, Atten= 98%, Lag= 296.3 min
Primary = 0.46 cfs @ 16.90 hrs, Volume= 1.063 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 634.32' @ 16.90 hrs Surf.Area= 19,307 sf Storage= 31,937 cf
Plug-Flow detention time= 1,657.5 min calculated for 1.063 af(100% of inflow)
Center-of-Mass det. time= 1,657.1 min ( 2,497.4 - 840.3 )
Volume Invert Avail.Storage Storage Description _
#1 632.50' 114,317 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
632.50 15,777 0 0
634.00 18,796 25,930 25,930
636.00 22,040 40,836 66,766
638.00 25,511 47,551 114,317
Device Routing Invert Outlet Devices
#1 Primary 628.00' 18.0" x 106.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 617.77' S= 0.0965 '/' Cc= 0.900 n= 0.012
#2 Device 1 632.50' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.158 0.221 0.284 0.347 0.410 0.473
#3 Device 1 634.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=0.46 cfs @ 16.90 hrs HW=634.32' (Free Discharge)
t-1=Culvert (Passes 0.46 cfs of 20.07 cfs potential flow)
2=Exfiltration (Custom Controls 0.21 cfs)
3=Orifice/Grate (Orifice Controls 0.25 cfs @ 1.91 fps)
4=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=632.50' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP2)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 632.50 0.00 0.00 0.00
5.00 0.00 0 632.50 0.00 0.00 0.00
10.00 0.05 35 632.50 0.00 0.00 0.00
15.00 0.65 31,338 634.28 0.42 0.42 0.00
20.00 0.30 31,236 634.28 0.41 0.41 0.00
25.00 0.00 28,919 634.16 0.27 0.27 0.00
30.00 0.00 25,119 633.96 0.19 0.19 0.00
35.00 0.00 21,857 633.78 0.18 0.18 0.00
40.00 0.00 18,791 633.61 0.17 0.17 0.00
45.00 0.00 15,925 633.45 0.15 0.15 0.00
50.00 0.00 13,426 633.31 0.13 0.13 0.00
55.00 0.00 11,304 633.19 0.11 0.11 0.00
60.00 0.00 9,505 633.08 0.09 0.09 0.00
65.00 0.00 7,985 632.99 0.08 0.08 0.00
70.00 0.00 6,702 632.91 0.07 0.07 0.00
75.00 0.00 5,620 632.85 0.06 0.06 0.00
80.00 0.00 4,710 632.79 0.05 0.05 0.00
85.00 0.00 3,945 632.75 0.04 0.04 0.00
90.00 0.00 3,303 632.71 0.03 0.03 0.00
95.00 0.00 2,764 632.67 0.03 0.03 0.00
100.00 0.00 2,313 632.65 0.02 0.02 0.00
105.00 0.00 1,934 632.62 0.02 0.02 0.00
110.00 0.00 1,617 632.60 0.02 0.02 0.00
115.00 0.00 1,352 632.59 0.01 0.01 0.00
120.00 0.00 1,130 632.57 0.01 0.01 0.00
125.00 0.00 945 632.56 0.01 0.01 0.00
130.00 0.00 789 632.55 0.01 0.01 0.00
135.00 0.00 660 632.54 0.01 0.01 0.00
140.00 0.00 551 632.53 0.01 0.01 0.00
145.00 0.00 461 632.53 0.00 0.00 0.00
150.00 0.00 385 632.52 0.00 0.00 0.00
155.00 0.00 322 632.52 0.00 0.00 0.00
160.00 0.00 269 632.52 0.00 0.00 0.00
165.00 0.00 225 632.51 0.00 0.00 0.00
170.00 0.00 188 632.51 0.00 0.00 0.00
175.00 0.00 157 632.51 0.00 0.00 0.00
180.00 0.00 131 632.51 0.00 0.00 0.00
185.00 0.00 109 632.51 0.00 0.00 0.00
190.00 0.00 91 632.51 0.00 0.00 0.00
195.00 0.00 76 632.50 0.00 0.00 0.00
200.00 0.00 64 632.50 0.00 0.00 0.00

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP2)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
632.50 0.00 0.00 0.00 637.70 41.09 25.46 15.64
632.60 0.02 0.02 0.00 637.80 44.49 25.60 18.89
632.70 0.03 0.03 0.00 637.90 48.24 25.74 22.50
632.80 0.05 0.05 0.00 638.00 52.18 25.88 26.30
632.90 0.06 0.06 0.00 638.10 56.42 26.02 30.40
633.00 0.08 0.08 0.00 638.20 60.86 26.16 34.70
633.10 0.09 0.09 0.00 638.30 65.43 26.29 39.13
633.20 0.11 0.11 0.00 638.40 70.16 26.43 43.73
633.30 0.13 0.13 0.00 638.50 74.98 26.57 48.41
633.40 0.14 0.14 0.00
633.50 0.16 0.16 0.00
633.60 0.16 0.16 0.00
633.70 0.17 0.17 0.00
633.80 0.18 0.18 0.00
633.90 0.18 0.18 0.00
634.00 0.19 0.19 0.00
634.10 0.23 0.23 0.00
634.20 0.31 0.31 0.00
634.30 0.44 0.44 0.00
634.40 0.58 0.58 0.00
634.50 0.69 0.69 0.00
634.60 0.79 0.79 0.00
634.70 0.87 0.87 0.00
634.80 0.94 0.94 0.00
634.90 1.01 1.01 0.00
635.00 1.07 1.07 0.00
635.10 1.13 1.13 0.00
635.20 1.19 1.19 0.00
635.30 1.24 1.24 0.00
635.40 1.29 1.29 0.00
635.50 1.34 1.34 0.00
635.60 1.39 1.39 0.00
635.70 1.44 1.44 0.00
635.80 1.48 1.48 0.00
635.90 1.52 1.52 0.00
636.00 1.57 1.57 0.00
636.10 2.64 2.64 0.00
636.20 4.57 4.57 0.00
636.30 7.06 7.06 0.00
636.40 10.00 10.00 0.00
636.50 13.33 13.33 0.00
636.60 17.00 17.00 0.00
636.70 20.99 20.99 0.00
636.80 24.14 24.14 0.00
636.90 24.29 24.29 0.00
637.00 24.44 24.44 0.00
637.10 25.43 24.59 0.85
637.20 27.13 24.73 2.40
637.30 29.30 24.88 4.42
637.40 31.86 25.03 6.83
637.50 34.72 25.17 9.55
637.60 37.86 25.31 12.55

2020.17-BMP2 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP2)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
632.50 15,777 0 637.70 24,990 106,742
632.60 15,978 1,588 637.80 25,164 109,249
632.70 16,180 3,196 637.90 25,337 111,774
632.80 16,381 4,824 638.00 25,511 114,317
632.90 16,582 6,472 638.10 25,511 114,317
633.00 16,783 8,140 638.20 25,511 114,317
633.10 16,985 9,828 638.30 25,511 114,317
633.20 17,186 11,537 638.40 25,511 114,317
633.30 17,387 13,266 638.50 25,511 114,317
633.40 17,588 15,014
633.50 17,790 16,783
633.60 17,991 18,572
633.70 18,192 20,382
633.80 18,393 22,211
633.90 18,595 24,060
634.00 18,796 25,930
634.10 18,958 27,817
634.20 19,120 29,721
634.30 19,283 31,642
634.40 19,445 33,578
634.50 19,607 35,531
634.60 19,769 37,499
634.70 19,931 39,484
634.80 20,094 41,486
634.90 20,256 43,503
635.00 20,418 45,537
635.10 20,580 47,587
635.20 20,742 49,653
635.30 20,905 51,735
635.40 21,067 53,834
635.50 21,229 55,949
635.60 21,391 58,080
635.70 21,553 60,227
635.80 21,716 62,390
635.90 21,878 64,570
636.00 22,040 66,766
636.10 22,214 68,978
636.20 22,387 71,208
636.30 22,561 73,456
636.40 22,734 75,721
636.50 22,908 78,003
636.60 23,081 80,302
636.70 23,255 82,619
636.80 23,428 84,953
636.90 23,602 87,305
637.00 23,776 89,674
637.10 23,949 92,060
637.20 24,123 94,463
637.30 24,296 96,884
637.40 24,470 99,323
637.50 24,643 101,778
637.60 24,817 104,251

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=10.330 ac Runoff Depth=1.95"
Flow Length=729' Tc=15.7 min CN=68 Runoff=25.11 cfs 1.680 af
Subcatchment 2S: (Post Developed) Runoff Area=10.330 ac Runoff Depth=3.07"
Tc=5.0 min CN=81 Runoff=57.82 cfs 2.646 af
Pond 3P: (BMP2) Peak Elev=636.11' Storage=69,110 cf Inflow=57.82 cfs 2.646 af
Primary=2.75 cfs 2.644 af Secondary=0.00 cfs 0.000 af Outflow=2.75 cfs 2.644 af
Total Runoff Area = 20.660 ac Runoff Volume = 4.326 af Average Runoff Depth = 2.51"
78.56% Pervious Area = 16.230 ac 21.44% Impervious Area = 4.430 ac

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 25.11 cfs @ 12.09 hrs, Volume= 1.680 af, Depth= 1.95"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description _
4.220 60 Woods, Fair, HSG B
0.210 73 Woods, Fair, HSG C
3.190 79 Pasture/grassland/range, Fair, HSG C
2.710 69 Pasture/grassland/range, Fair, HSG B
10.330 68 Weighted Average
10.330 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.9 100 0.0586 0.19 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.8 629 0.0482 1.54 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
15.7 729 Total

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 1.95 0.00
2.00 0.11 0.00 0.00 106.00 5.10 1.95 0.00
4.00 0.24 0.00 0.00 108.00 5.10 1.95 0.00
6.00 0.41 0.00 0.00 110.00 5.10 1.95 0.00
8.00 0.61 0.00 0.00 112.00 5.10 1.95 0.00
10.00 0.92 0.00 0.00 114.00 5.10 1.95 0.00
12.00 3.38 0.83 19.06 116.00 5.10 1.95 0.00
14.00 4.18 1.32 1.43 118.00 5.10 1.95 0.00
16.00 4.49 1.52 0.88 120.00 5.10 1.95 0.00
18.00 4.70 1.67 0.68 122.00 5.10 1.95 0.00
20.00 4.86 1.78 0.51 124.00 5.10 1.95 0.00
22.00 4.98 1.87 0.46 126.00 5.10 1.95 0.00
24.00 5.10 1.95 0.42 128.00 5.10 1.95 0.00
26.00 5.10 1.95 0.00 130.00 5.10 1.95 0.00
28.00 5.10 1.95 0.00 132.00 5.10 1.95 0.00
30.00 5.10 1.95 0.00 134.00 5.10 1.95 0.00
32.00 5.10 1.95 0.00 136.00 5.10 1.95 0.00
34.00 5.10 1.95 0.00 138.00 5.10 1.95 0.00
36.00 5.10 1.95 0.00 140.00 5.10 1.95 0.00
38.00 5.10 1.95 0.00 142.00 5.10 1.95 0.00
40.00 5.10 1.95 0.00 144.00 5.10 1.95 0.00
42.00 5.10 1.95 0.00 146.00 5.10 1.95 0.00
44.00 5.10 1.95 0.00 148.00 5.10 1.95 0.00
46.00 5.10 1.95 0.00 150.00 5.10 1.95 0.00
48.00 5.10 1.95 0.00 152.00 5.10 1.95 0.00
50.00 5.10 1.95 0.00 154.00 5.10 1.95 0.00
52.00 5.10 1.95 0.00 156.00 5.10 1.95 0.00
54.00 5.10 1.95 0.00 158.00 5.10 1.95 0.00
56.00 5.10 1.95 0.00 160.00 5.10 1.95 0.00
58.00 5.10 1.95 0.00 162.00 5.10 1.95 0.00
60.00 5.10 1.95 0.00 164.00 5.10 1.95 0.00
62.00 5.10 1.95 0.00 166.00 5.10 1.95 0.00
64.00 5.10 1.95 0.00 168.00 5.10 1.95 0.00
66.00 5.10 1.95 0.00 170.00 5.10 1.95 0.00
68.00 5.10 1.95 0.00 172.00 5.10 1.95 0.00
70.00 5.10 1.95 0.00 174.00 5.10 1.95 0.00
72.00 5.10 1.95 0.00 176.00 5.10 1.95 0.00
74.00 5.10 1.95 0.00 178.00 5.10 1.95 0.00
76.00 5.10 1.95 0.00 180.00 5.10 1.95 0.00
78.00 5.10 1.95 0.00 182.00 5.10 1.95 0.00
80.00 5.10 1.95 0.00 184.00 5.10 1.95 0.00
82.00 5.10 1.95 0.00 186.00 5.10 1.95 0.00
84.00 5.10 1.95 0.00 188.00 5.10 1.95 0.00
86.00 5.10 1.95 0.00 190.00 5.10 1.95 0.00
88.00 5.10 1.95 0.00 192.00 5.10 1.95 0.00
90.00 5.10 1.95 0.00 194.00 5.10 1.95 0.00
92.00 5.10 1.95 0.00 196.00 5.10 1.95 0.00
94.00 5.10 1.95 0.00 198.00 5.10 1.95 0.00
96.00 5.10 1.95 0.00 200.00 5.10 1.95 0.00
98.00 5.10 1.95 0.00
100.00 5.10 1.95 0.00
102.00 5.10 1.95 0.00

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 57.82 cfs @ 11.96 hrs, Volume= 2.646 af, Depth= 3.07"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
4.430 98 Paved parking & roofs
5.900 69 50-75% Grass cover, Fair, HSG B
10.330 81 Weighted Average
5.900 Pervious Area
4.430 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.07 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.07 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.07 0.00
6.00 0.41 0.00 0.00 110.00 5.10 3.07 0.00
8.00 0.61 0.01 0.12 112.00 5.10 3.07 0.00
10.00 0.92 0.07 0.60 114.00 5.10 3.07 0.00
12.00 3.38 1.61 49.22 116.00 5.10 3.07 0.00
14.00 4.18 2.28 1.74 118.00 5.10 3.07 0.00
16.00 4.49 2.54 1.08 120.00 5.10 3.07 0.00
18.00 4.70 2.72 0.84 122.00 5.10 3.07 0.00
20.00 4.86 2.86 0.62 124.00 5.10 3.07 0.00
22.00 4.98 2.97 0.56 126.00 5.10 3.07 0.00
24.00 5.10 3.07 0.52 128.00 5.10 3.07 0.00
26.00 5.10 3.07 0.00 130.00 5.10 3.07 0.00
28.00 5.10 3.07 0.00 132.00 5.10 3.07 0.00
30.00 5.10 3.07 0.00 134.00 5.10 3.07 0.00
32.00 5.10 3.07 0.00 136.00 5.10 3.07 0.00
34.00 5.10 3.07 0.00 138.00 5.10 3.07 0.00
36.00 5.10 3.07 0.00 140.00 5.10 3.07 0.00
38.00 5.10 3.07 0.00 142.00 5.10 3.07 0.00
40.00 5.10 3.07 0.00 144.00 5.10 3.07 0.00
42.00 5.10 3.07 0.00 146.00 5.10 3.07 0.00
44.00 5.10 3.07 0.00 148.00 5.10 3.07 0.00
46.00 5.10 3.07 0.00 150.00 5.10 3.07 0.00
48.00 5.10 3.07 0.00 152.00 5.10 3.07 0.00
50.00 5.10 3.07 0.00 154.00 5.10 3.07 0.00
52.00 5.10 3.07 0.00 156.00 5.10 3.07 0.00
54.00 5.10 3.07 0.00 158.00 5.10 3.07 0.00
56.00 5.10 3.07 0.00 160.00 5.10 3.07 0.00
58.00 5.10 3.07 0.00 162.00 5.10 3.07 0.00
60.00 5.10 3.07 0.00 164.00 5.10 3.07 0.00
62.00 5.10 3.07 0.00 166.00 5.10 3.07 0.00
64.00 5.10 3.07 0.00 168.00 5.10 3.07 0.00
66.00 5.10 3.07 0.00 170.00 5.10 3.07 0.00
68.00 5.10 3.07 0.00 172.00 5.10 3.07 0.00
70.00 5.10 3.07 0.00 174.00 5.10 3.07 0.00
72.00 5.10 3.07 0.00 176.00 5.10 3.07 0.00
74.00 5.10 3.07 0.00 178.00 5.10 3.07 0.00
76.00 5.10 3.07 0.00 180.00 5.10 3.07 0.00
78.00 5.10 3.07 0.00 182.00 5.10 3.07 0.00
80.00 5.10 3.07 0.00 184.00 5.10 3.07 0.00
82.00 5.10 3.07 0.00 186.00 5.10 3.07 0.00
84.00 5.10 3.07 0.00 188.00 5.10 3.07 0.00
86.00 5.10 3.07 0.00 190.00 5.10 3.07 0.00
88.00 5.10 3.07 0.00 192.00 5.10 3.07 0.00
90.00 5.10 3.07 0.00 194.00 5.10 3.07 0.00
92.00 5.10 3.07 0.00 196.00 5.10 3.07 0.00
94.00 5.10 3.07 0.00 198.00 5.10 3.07 0.00
96.00 5.10 3.07 0.00 200.00 5.10 3.07 0.00
98.00 5.10 3.07 0.00
100.00 5.10 3.07 0.00
102.00 5.10 3.07 0.00

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP2)
Inflow Area = 10.330 ac, Inflow Depth = 3.07" for 10-yr Concord event
Inflow = 57.82 cfs @ 11.96 hrs, Volume= 2.646 af
Outflow = 2.75 cfs @ 13.07 hrs, Volume= 2.644 af, Atten= 95%, Lag= 66.3 min
Primary = 2.75 cfs @ 13.07 hrs, Volume= 2.644 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 636.11' @ 13.07 hrs Surf.Area= 22,224 sf Storage= 69,110 cf
Plug-Flow detention time= 988.7 min calculated for 2.644 af(100% of inflow)
Center-of-Mass det. time= 988.7 min ( 1,802.9 - 814.2 )
Volume Invert Avail.Storage Storage Description
#1 632.50' 114,317 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
632.50 15,777 0 0
634.00 18,796 25,930 25,930
636.00 22,040 40,836 66,766
638.00 25,511 47,551 114,317
Device Routing Invert Outlet Devices
#1 Primary 628.00' 18.0" x 106.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 617.77' S= 0.0965 '/' Cc= 0.900 n= 0.012
#2 Device 1 632.50' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.158 0.221 0.284 0.347 0.410 0.473
#3 Device 1 634.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=2.74 cfs @ 13.07 hrs HW=636.11' (Free Discharge)
t-1=Culvert (Passes 2.74 cfs of 23.08 cfs potential flow)
2=Exfiltration (Custom Controls 0.32 cfs)
3=Orifice/Grate (Orifice Controls 1.29 cfs @ 6.56 fps)
4=Top of Riser (Weir Controls 1.13 cfs @ 1.06 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=632.50' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP2)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 632.50 0.00 0.00 0.00
5.00 0.00 0 632.50 0.00 0.00 0.00
10.00 0.60 2,505 632.66 0.02 0.02 0.00
15.00 1.39 67,063 636.01 1.66 1.66 0.00
20.00 0.62 56,888 635.54 1.36 1.36 0.00
25.00 0.00 43,469 634.90 1.01 1.01 0.00
30.00 0.00 30,904 634.26 0.39 0.39 0.00
35.00 0.00 26,279 634.02 0.19 0.19 0.00
40.00 0.00 22,946 633.84 0.18 0.18 0.00
45.00 0.00 19,814 633.67 0.17 0.17 0.00
50.00 0.00 16,872 633.50 0.16 0.16 0.00
55.00 0.00 14,232 633.36 0.14 0.14 0.00
60.00 0.00 11,988 633.23 0.11 0.11 0.00
65.00 0.00 10,085 633.12 0.10 0.10 0.00
70.00 0.00 8,474 633.02 0.08 0.08 0.00
75.00 0.00 7,114 632.94 0.07 0.07 0.00
80.00 0.00 5,968 632.87 0.06 0.06 0.00
85.00 0.00 5,003 632.81 0.05 0.05 0.00
90.00 0.00 4,191 632.76 0.04 0.04 0.00
95.00 0.00 3,509 632.72 0.03 0.03 0.00
100.00 0.00 2,937 632.68 0.03 0.03 0.00
105.00 0.00 2,458 632.65 0.02 0.02 0.00
110.00 0.00 2,056 632.63 0.02 0.02 0.00
115.00 0.00 1,719 632.61 0.02 0.02 0.00
120.00 0.00 1,437 632.59 0.01 0.01 0.00
125.00 0.00 1,201 632.58 0.01 0.01 0.00
130.00 0.00 1,004 632.56 0.01 0.01 0.00
135.00 0.00 839 632.55 0.01 0.01 0.00
140.00 0.00 701 632.54 0.01 0.01 0.00
145.00 0.00 586 632.54 0.01 0.01 0.00
150.00 0.00 490 632.53 0.00 0.00 0.00
155.00 0.00 409 632.53 0.00 0.00 0.00
160.00 0.00 342 632.52 0.00 0.00 0.00
165.00 0.00 286 632.52 0.00 0.00 0.00
170.00 0.00 239 632.52 0.00 0.00 0.00
175.00 0.00 199 632.51 0.00 0.00 0.00
180.00 0.00 167 632.51 0.00 0.00 0.00
185.00 0.00 139 632.51 0.00 0.00 0.00
190.00 0.00 116 632.51 0.00 0.00 0.00
195.00 0.00 97 632.51 0.00 0.00 0.00
200.00 0.00 81 632.51 0.00 0.00 0.00

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP2)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
632.50 0.00 0.00 0.00 637.70 41.09 25.46 15.64
632.60 0.02 0.02 0.00 637.80 44.49 25.60 18.89
632.70 0.03 0.03 0.00 637.90 48.24 25.74 22.50
632.80 0.05 0.05 0.00 638.00 52.18 25.88 26.30
632.90 0.06 0.06 0.00 638.10 56.42 26.02 30.40
633.00 0.08 0.08 0.00 638.20 60.86 26.16 34.70
633.10 0.09 0.09 0.00 638.30 65.43 26.29 39.13
633.20 0.11 0.11 0.00 638.40 70.16 26.43 43.73
633.30 0.13 0.13 0.00 638.50 74.98 26.57 48.41
633.40 0.14 0.14 0.00
633.50 0.16 0.16 0.00
633.60 0.16 0.16 0.00
633.70 0.17 0.17 0.00
633.80 0.18 0.18 0.00
633.90 0.18 0.18 0.00
634.00 0.19 0.19 0.00
634.10 0.23 0.23 0.00
634.20 0.31 0.31 0.00
634.30 0.44 0.44 0.00
634.40 0.58 0.58 0.00
634.50 0.69 0.69 0.00
634.60 0.79 0.79 0.00
634.70 0.87 0.87 0.00
634.80 0.94 0.94 0.00
634.90 1.01 1.01 0.00
635.00 1.07 1.07 0.00
635.10 1.13 1.13 0.00
635.20 1.19 1.19 0.00
635.30 1.24 1.24 0.00
635.40 1.29 1.29 0.00
635.50 1.34 1.34 0.00
635.60 1.39 1.39 0.00
635.70 1.44 1.44 0.00
635.80 1.48 1.48 0.00
635.90 1.52 1.52 0.00
636.00 1.57 1.57 0.00
636.10 2.64 2.64 0.00
636.20 4.57 4.57 0.00
636.30 7.06 7.06 0.00
636.40 10.00 10.00 0.00
636.50 13.33 13.33 0.00
636.60 17.00 17.00 0.00
636.70 20.99 20.99 0.00
636.80 24.14 24.14 0.00
636.90 24.29 24.29 0.00
637.00 24.44 24.44 0.00
637.10 25.43 24.59 0.85
637.20 27.13 24.73 2.40
637.30 29.30 24.88 4.42
637.40 31.86 25.03 6.83
637.50 34.72 25.17 9.55
637.60 37.86 25.31 12.55

2020.17-BMP2 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP2)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
632.50 15,777 0 637.70 24,990 106,742
632.60 15,978 1,588 637.80 25,164 109,249
632.70 16,180 3,196 637.90 25,337 111,774
632.80 16,381 4,824 638.00 25,511 114,317
632.90 16,582 6,472 638.10 25,511 114,317
633.00 16,783 8,140 638.20 25,511 114,317
633.10 16,985 9,828 638.30 25,511 114,317
633.20 17,186 11,537 638.40 25,511 114,317
633.30 17,387 13,266 638.50 25,511 114,317
633.40 17,588 15,014
633.50 17,790 16,783
633.60 17,991 18,572
633.70 18,192 20,382
633.80 18,393 22,211
633.90 18,595 24,060
634.00 18,796 25,930
634.10 18,958 27,817
634.20 19,120 29,721
634.30 19,283 31,642
634.40 19,445 33,578
634.50 19,607 35,531
634.60 19,769 37,499
634.70 19,931 39,484
634.80 20,094 41,486
634.90 20,256 43,503
635.00 20,418 45,537
635.10 20,580 47,587
635.20 20,742 49,653
635.30 20,905 51,735
635.40 21,067 53,834
635.50 21,229 55,949
635.60 21,391 58,080
635.70 21,553 60,227
635.80 21,716 62,390
635.90 21,878 64,570
636.00 22,040 66,766
636.10 22,214 68,978
636.20 22,387 71,208
636.30 22,561 73,456
636.40 22,734 75,721
636.50 22,908 78,003
636.60 23,081 80,302
636.70 23,255 82,619
636.80 23,428 84,953
636.90 23,602 87,305
637.00 23,776 89,674
637.10 23,949 92,060
637.20 24,123 94,463
637.30 24,296 96,884
637.40 24,470 99,323
637.50 24,643 101,778
637.60 24,817 104,251

2020.17-BMP2 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=10.330 ac Runoff Depth=2.62"
Flow Length=729' Tc=15.7 min CN=68 Runoff=34.11 cfs 2.256 af
Subcatchment 2S: (Post Developed) Runoff Area=10.330 ac Runoff Depth=3.88"
Tc=5.0 min CN=81 Runoff=72.24 cfs 3.343 af
Pond 3P: (BMP2) Peak Elev=636.41' Storage=75,959 cf Inflow=72.24 cfs 3.343 af
Primary=10.34 cfs 3.341 af Secondary=0.00 cfs 0.000 af Outflow=10.34 cfs 3.341 af
Total Runoff Area = 20.660 ac Runoff Volume = 5.599 af Average Runoff Depth = 3.25"
78.56% Pervious Area = 16.230 ac 21.44% Impervious Area = 4.430 ac

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 34.11 cfs @ 12.09 hrs, Volume= 2.256 af, Depth= 2.62"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description _
4.220 60 Woods, Fair, HSG B
0.210 73 Woods, Fair, HSG C
3.190 79 Pasture/grassland/range, Fair, HSG C
2.710 69 Pasture/grassland/range, Fair, HSG B
10.330 68 Weighted Average
10.330 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.9 100 0.0586 0.19 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.8 629 0.0482 1.54 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
15.7 729 Total

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 2.62 0.00
2.00 0.13 0.00 0.00 106.00 6.00 2.62 0.00
4.00 0.29 0.00 0.00 108.00 6.00 2.62 0.00
6.00 0.48 0.00 0.00 110.00 6.00 2.62 0.00
8.00 0.72 0.00 0.00 112.00 6.00 2.62 0.00
10.00 1.09 0.00 0.09 114.00 6.00 2.62 0.00
12.00 3.98 1.19 26.55 116.00 6.00 2.62 0.00
14.00 4.92 1.82 1.84 118.00 6.00 2.62 0.00
16.00 5.28 2.08 1.12 120.00 6.00 2.62 0.00
18.00 5.53 2.26 0.86 122.00 6.00 2.62 0.00
20.00 5.71 2.40 0.64 124.00 6.00 2.62 0.00
22.00 5.86 2.52 0.58 126.00 6.00 2.62 0.00
24.00 6.00 2.62 0.53 128.00 6.00 2.62 0.00
26.00 6.00 2.62 0.00 130.00 6.00 2.62 0.00
28.00 6.00 2.62 0.00 132.00 6.00 2.62 0.00
30.00 6.00 2.62 0.00 134.00 6.00 2.62 0.00
32.00 6.00 2.62 0.00 136.00 6.00 2.62 0.00
34.00 6.00 2.62 0.00 138.00 6.00 2.62 0.00
36.00 6.00 2.62 0.00 140.00 6.00 2.62 0.00
38.00 6.00 2.62 0.00 142.00 6.00 2.62 0.00
40.00 6.00 2.62 0.00 144.00 6.00 2.62 0.00
42.00 6.00 2.62 0.00 146.00 6.00 2.62 0.00
44.00 6.00 2.62 0.00 148.00 6.00 2.62 0.00
46.00 6.00 2.62 0.00 150.00 6.00 2.62 0.00
48.00 6.00 2.62 0.00 152.00 6.00 2.62 0.00
50.00 6.00 2.62 0.00 154.00 6.00 2.62 0.00
52.00 6.00 2.62 0.00 156.00 6.00 2.62 0.00
54.00 6.00 2.62 0.00 158.00 6.00 2.62 0.00
56.00 6.00 2.62 0.00 160.00 6.00 2.62 0.00
58.00 6.00 2.62 0.00 162.00 6.00 2.62 0.00
60.00 6.00 2.62 0.00 164.00 6.00 2.62 0.00
62.00 6.00 2.62 0.00 166.00 6.00 2.62 0.00
64.00 6.00 2.62 0.00 168.00 6.00 2.62 0.00
66.00 6.00 2.62 0.00 170.00 6.00 2.62 0.00
68.00 6.00 2.62 0.00 172.00 6.00 2.62 0.00
70.00 6.00 2.62 0.00 174.00 6.00 2.62 0.00
72.00 6.00 2.62 0.00 176.00 6.00 2.62 0.00
74.00 6.00 2.62 0.00 178.00 6.00 2.62 0.00
76.00 6.00 2.62 0.00 180.00 6.00 2.62 0.00
78.00 6.00 2.62 0.00 182.00 6.00 2.62 0.00
80.00 6.00 2.62 0.00 184.00 6.00 2.62 0.00
82.00 6.00 2.62 0.00 186.00 6.00 2.62 0.00
84.00 6.00 2.62 0.00 188.00 6.00 2.62 0.00
86.00 6.00 2.62 0.00 190.00 6.00 2.62 0.00
88.00 6.00 2.62 0.00 192.00 6.00 2.62 0.00
90.00 6.00 2.62 0.00 194.00 6.00 2.62 0.00
92.00 6.00 2.62 0.00 196.00 6.00 2.62 0.00
94.00 6.00 2.62 0.00 198.00 6.00 2.62 0.00
96.00 6.00 2.62 0.00 200.00 6.00 2.62 0.00
98.00 6.00 2.62 0.00
100.00 6.00 2.62 0.00
102.00 6.00 2.62 0.00

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 72.24 cfs @ 11.96 hrs, Volume= 3.343 af, Depth= 3.88"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
4.430 98 Paved parking & roofs
5.900 69 50-75% Grass cover, Fair, HSG B
10.330 81 Weighted Average
5.900 Pervious Area
4.430 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 3.88 0.00
2.00 0.13 0.00 0.00 106.00 6.00 3.88 0.00
4.00 0.29 0.00 0.00 108.00 6.00 3.88 0.00
6.00 0.48 0.00 0.00 110.00 6.00 3.88 0.00
8.00 0.72 0.02 0.24 112.00 6.00 3.88 0.00
10.00 1.09 0.13 0.89 114.00 6.00 3.88 0.00
12.00 3.98 2.10 61.17 116.00 6.00 3.88 0.00
14.00 4.92 2.91 2.12 118.00 6.00 3.88 0.00
16.00 5.28 3.23 1.31 120.00 6.00 3.88 0.00
18.00 5.53 3.45 1.02 122.00 6.00 3.88 0.00
20.00 5.71 3.62 0.75 124.00 6.00 3.88 0.00
22.00 5.86 3.76 0.68 126.00 6.00 3.88 0.00
24.00 6.00 3.88 0.63 128.00 6.00 3.88 0.00
26.00 6.00 3.88 0.00 130.00 6.00 3.88 0.00
28.00 6.00 3.88 0.00 132.00 6.00 3.88 0.00
30.00 6.00 3.88 0.00 134.00 6.00 3.88 0.00
32.00 6.00 3.88 0.00 136.00 6.00 3.88 0.00
34.00 6.00 3.88 0.00 138.00 6.00 3.88 0.00
36.00 6.00 3.88 0.00 140.00 6.00 3.88 0.00
38.00 6.00 3.88 0.00 142.00 6.00 3.88 0.00
40.00 6.00 3.88 0.00 144.00 6.00 3.88 0.00
42.00 6.00 3.88 0.00 146.00 6.00 3.88 0.00
44.00 6.00 3.88 0.00 148.00 6.00 3.88 0.00
46.00 6.00 3.88 0.00 150.00 6.00 3.88 0.00
48.00 6.00 3.88 0.00 152.00 6.00 3.88 0.00
50.00 6.00 3.88 0.00 154.00 6.00 3.88 0.00
52.00 6.00 3.88 0.00 156.00 6.00 3.88 0.00
54.00 6.00 3.88 0.00 158.00 6.00 3.88 0.00
56.00 6.00 3.88 0.00 160.00 6.00 3.88 0.00
58.00 6.00 3.88 0.00 162.00 6.00 3.88 0.00
60.00 6.00 3.88 0.00 164.00 6.00 3.88 0.00
62.00 6.00 3.88 0.00 166.00 6.00 3.88 0.00
64.00 6.00 3.88 0.00 168.00 6.00 3.88 0.00
66.00 6.00 3.88 0.00 170.00 6.00 3.88 0.00
68.00 6.00 3.88 0.00 172.00 6.00 3.88 0.00
70.00 6.00 3.88 0.00 174.00 6.00 3.88 0.00
72.00 6.00 3.88 0.00 176.00 6.00 3.88 0.00
74.00 6.00 3.88 0.00 178.00 6.00 3.88 0.00
76.00 6.00 3.88 0.00 180.00 6.00 3.88 0.00
78.00 6.00 3.88 0.00 182.00 6.00 3.88 0.00
80.00 6.00 3.88 0.00 184.00 6.00 3.88 0.00
82.00 6.00 3.88 0.00 186.00 6.00 3.88 0.00
84.00 6.00 3.88 0.00 188.00 6.00 3.88 0.00
86.00 6.00 3.88 0.00 190.00 6.00 3.88 0.00
88.00 6.00 3.88 0.00 192.00 6.00 3.88 0.00
90.00 6.00 3.88 0.00 194.00 6.00 3.88 0.00
92.00 6.00 3.88 0.00 196.00 6.00 3.88 0.00
94.00 6.00 3.88 0.00 198.00 6.00 3.88 0.00
96.00 6.00 3.88 0.00 200.00 6.00 3.88 0.00
98.00 6.00 3.88 0.00
100.00 6.00 3.88 0.00
102.00 6.00 3.88 0.00

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP2)
Inflow Area = 10.330 ac, Inflow Depth = 3.88" for 25-yr Concord event
Inflow = 72.24 cfs @ 11.96 hrs, Volume= 3.343 af
Outflow = 10.34 cfs @ 12.16 hrs, Volume= 3.341 af, Atten= 86%, Lag= 12.2 min
Primary = 10.34 cfs @ 12.16 hrs, Volume= 3.341 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 636.41' @ 12.16 hrs Surf.Area= 22,752 sf Storage= 75,959 cf
Plug-Flow detention time= 817.1 min calculated for 3.341 af(100% of inflow)
Center-of-Mass det. time= 817.3 min ( 1,624.8 - 807.6 )
Volume Invert Avail.Storage Storage Description
#1 632.50' 114,317 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
632.50 15,777 0 0
634.00 18,796 25,930 25,930
636.00 22,040 40,836 66,766
638.00 25,511 47,551 114,317
Device Routing Invert Outlet Devices
#1 Primary 628.00' 18.0" x 106.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 617.77' S= 0.0965 'I' Cc= 0.900 n= 0.012
#2 Device 1 632.50' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.158 0.221 0.284 0.347 0.410 0.473
#3 Device 1 634.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=10.33 cfs @ 12.16 hrs HW=636.41' (Free Discharge)
t-1=Culvert (Passes 10.33 cfs of 23.55 cfs potential flow)
2=Exfiltration (Custom Controls 0.34 cfs)
3=Orifice/Grate (Orifice Controls 1.39 cfs @ 7.08 fps)
4=Top of Riser (Weir Controls 8.60 cfs @ 2.09 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=632.50' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP2)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 632.50 0.00 0.00 0.00
5.00 0.00 0 632.50 0.00 0.00 0.00
10.00 0.89 4,384 632.77 0.04 0.04 0.00
15.00 1.69 67,751 636.04 1.91 1.91 0.00
20.00 0.75 59,853 635.68 1.43 1.43 0.00
25.00 0.00 46,670 635.06 1.10 1.10 0.00
30.00 0.00 32,211 634.33 0.48 0.48 0.00
35.00 0.00 26,879 634.05 0.20 0.20 0.00
40.00 0.00 23,492 633.87 0.18 0.18 0.00
45.00 0.00 20,328 633.70 0.17 0.17 0.00
50.00 0.00 17,355 633.53 0.16 0.16 0.00
55.00 0.00 14,647 633.38 0.14 0.14 0.00
60.00 0.00 12,340 633.25 0.12 0.12 0.00
65.00 0.00 10,383 633.13 0.10 0.10 0.00
70.00 0.00 8,727 633.03 0.08 0.08 0.00
75.00 0.00 7,328 632.95 0.07 0.07 0.00
80.00 0.00 6,147 632.88 0.06 0.06 0.00
85.00 0.00 5,154 632.82 0.05 0.05 0.00
90.00 0.00 4,318 632.77 0.04 0.04 0.00
95.00 0.00 3,616 632.73 0.04 0.04 0.00
100.00 0.00 3,027 632.69 0.03 0.03 0.00
105.00 0.00 2,533 632.66 0.03 0.03 0.00
110.00 0.00 2,118 632.63 0.02 0.02 0.00
115.00 0.00 1,772 632.61 0.02 0.02 0.00
120.00 0.00 1,481 632.59 0.01 0.01 0.00
125.00 0.00 1,238 632.58 0.01 0.01 0.00
130.00 0.00 1,035 632.57 0.01 0.01 0.00
135.00 0.00 865 632.55 0.01 0.01 0.00
140.00 0.00 723 632.55 0.01 0.01 0.00
145.00 0.00 604 632.54 0.01 0.01 0.00
150.00 0.00 505 632.53 0.01 0.01 0.00
155.00 0.00 422 632.53 0.00 0.00 0.00
160.00 0.00 352 632.52 0.00 0.00 0.00
165.00 0.00 294 632.52 0.00 0.00 0.00
170.00 0.00 246 632.52 0.00 0.00 0.00
175.00 0.00 206 632.51 0.00 0.00 0.00
180.00 0.00 172 632.51 0.00 0.00 0.00
185.00 0.00 144 632.51 0.00 0.00 0.00
190.00 0.00 120 632.51 0.00 0.00 0.00
195.00 0.00 100 632.51 0.00 0.00 0.00
200.00 0.00 84 632.51 0.00 0.00 0.00

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP2)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
632.50 0.00 0.00 0.00 637.70 41.09 25.46 15.64
632.60 0.02 0.02 0.00 637.80 44.49 25.60 18.89
632.70 0.03 0.03 0.00 637.90 48.24 25.74 22.50
632.80 0.05 0.05 0.00 638.00 52.18 25.88 26.30
632.90 0.06 0.06 0.00 638.10 56.42 26.02 30.40
633.00 0.08 0.08 0.00 638.20 60.86 26.16 34.70
633.10 0.09 0.09 0.00 638.30 65.43 26.29 39.13
633.20 0.11 0.11 0.00 638.40 70.16 26.43 43.73
633.30 0.13 0.13 0.00 638.50 74.98 26.57 48.41
633.40 0.14 0.14 0.00
633.50 0.16 0.16 0.00
633.60 0.16 0.16 0.00
633.70 0.17 0.17 0.00
633.80 0.18 0.18 0.00
633.90 0.18 0.18 0.00
634.00 0.19 0.19 0.00
634.10 0.23 0.23 0.00
634.20 0.31 0.31 0.00
634.30 0.44 0.44 0.00
634.40 0.58 0.58 0.00
634.50 0.69 0.69 0.00
634.60 0.79 0.79 0.00
634.70 0.87 0.87 0.00
634.80 0.94 0.94 0.00
634.90 1.01 1.01 0.00
635.00 1.07 1.07 0.00
635.10 1.13 1.13 0.00
635.20 1.19 1.19 0.00
635.30 1.24 1.24 0.00
635.40 1.29 1.29 0.00
635.50 1.34 1.34 0.00
635.60 1.39 1.39 0.00
635.70 1.44 1.44 0.00
635.80 1.48 1.48 0.00
635.90 1.52 1.52 0.00
636.00 1.57 1.57 0.00
636.10 2.64 2.64 0.00
636.20 4.57 4.57 0.00
636.30 7.06 7.06 0.00
636.40 10.00 10.00 0.00
636.50 13.33 13.33 0.00
636.60 17.00 17.00 0.00
636.70 20.99 20.99 0.00
636.80 24.14 24.14 0.00
636.90 24.29 24.29 0.00
637.00 24.44 24.44 0.00
637.10 25.43 24.59 0.85
637.20 27.13 24.73 2.40
637.30 29.30 24.88 4.42
637.40 31.86 25.03 6.83
637.50 34.72 25.17 9.55
637.60 37.86 25.31 12.55

2020.17-BMP2 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP2)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
632.50 15,777 0 637.70 24,990 106,742
632.60 15,978 1,588 637.80 25,164 109,249
632.70 16,180 3,196 637.90 25,337 111,774
632.80 16,381 4,824 638.00 25,511 114,317
632.90 16,582 6,472 638.10 25,511 114,317
633.00 16,783 8,140 638.20 25,511 114,317
633.10 16,985 9,828 638.30 25,511 114,317
633.20 17,186 11,537 638.40 25,511 114,317
633.30 17,387 13,266 638.50 25,511 114,317
633.40 17,588 15,014
633.50 17,790 16,783
633.60 17,991 18,572
633.70 18,192 20,382
633.80 18,393 22,211
633.90 18,595 24,060
634.00 18,796 25,930
634.10 18,958 27,817
634.20 19,120 29,721
634.30 19,283 31,642
634.40 19,445 33,578
634.50 19,607 35,531
634.60 19,769 37,499
634.70 19,931 39,484
634.80 20,094 41,486
634.90 20,256 43,503
635.00 20,418 45,537
635.10 20,580 47,587
635.20 20,742 49,653
635.30 20,905 51,735
635.40 21,067 53,834
635.50 21,229 55,949
635.60 21,391 58,080
635.70 21,553 60,227
635.80 21,716 62,390
635.90 21,878 64,570
636.00 22,040 66,766
636.10 22,214 68,978
636.20 22,387 71,208
636.30 22,561 73,456
636.40 22,734 75,721
636.50 22,908 78,003
636.60 23,081 80,302
636.70 23,255 82,619
636.80 23,428 84,953
636.90 23,602 87,305
637.00 23,776 89,674
637.10 23,949 92,060
637.20 24,123 94,463
637.30 24,296 96,884
637.40 24,470 99,323
637.50 24,643 101,778
637.60 24,817 104,251

2020.17-BMP2 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=10.330 ac Runoff Depth=3.25"
Flow Length=729' Tc=15.7 min CN=68 Runoff=42.44 cfs 2.797 af
Subcatchment 2S: (Post Developed) Runoff Area=10.330 ac Runoff Depth=4.62"
Tc=5.0 min CN=81 Runoff=85.12 cfs 3.976 af
Pond 3P: (BMP2) Peak Elev=636.82' Storage=85,431 cf Inflow=85.12 cfs 3.976 af
Primary=24.17 cfs 3.975 af Secondary=0.00 cfs 0.000 af Outflow=24.17 cfs 3.975 af
Total Runoff Area = 20.660 ac Runoff Volume = 6.773 af Average Runoff Depth = 3.93"
78.56% Pervious Area = 16.230 ac 21.44% Impervious Area = 4.430 ac

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 42.44 cfs @ 12.08 hrs, Volume= 2.797 af, Depth= 3.25"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description _
4.220 60 Woods, Fair, HSG B
0.210 73 Woods, Fair, HSG C
3.190 79 Pasture/grassland/range, Fair, HSG C
2.710 69 Pasture/grassland/range, Fair, HSG B
10.330 68 Weighted Average
10.330 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
8.9 100 0.0586 0.19 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
6.8 629 0.0482 1.54 Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
15.7 729 Total

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 3.25 0.00
2.00 0.15 0.00 0.00 106.00 6.80 3.25 0.00
4.00 0.33 0.00 0.00 108.00 6.80 3.25 0.00
6.00 0.54 0.00 0.00 110.00 6.80 3.25 0.00
8.00 0.82 0.00 0.00 112.00 6.80 3.25 0.00
10.00 1.23 0.02 0.23 114.00 6.80 3.25 0.00
12.00 4.51 1.54 33.57 116.00 6.80 3.25 0.00
14.00 5.58 2.30 2.20 118.00 6.80 3.25 0.00
16.00 5.98 2.61 1.34 120.00 6.80 3.25 0.00
18.00 6.26 2.82 1.03 122.00 6.80 3.25 0.00
20.00 6.47 2.99 0.76 124.00 6.80 3.25 0.00
22.00 6.64 3.12 0.68 126.00 6.80 3.25 0.00
24.00 6.80 3.25 0.63 128.00 6.80 3.25 0.00
26.00 6.80 3.25 0.00 130.00 6.80 3.25 0.00
28.00 6.80 3.25 0.00 132.00 6.80 3.25 0.00
30.00 6.80 3.25 0.00 134.00 6.80 3.25 0.00
32.00 6.80 3.25 0.00 136.00 6.80 3.25 0.00
34.00 6.80 3.25 0.00 138.00 6.80 3.25 0.00
36.00 6.80 3.25 0.00 140.00 6.80 3.25 0.00
38.00 6.80 3.25 0.00 142.00 6.80 3.25 0.00
40.00 6.80 3.25 0.00 144.00 6.80 3.25 0.00
42.00 6.80 3.25 0.00 146.00 6.80 3.25 0.00
44.00 6.80 3.25 0.00 148.00 6.80 3.25 0.00
46.00 6.80 3.25 0.00 150.00 6.80 3.25 0.00
48.00 6.80 3.25 0.00 152.00 6.80 3.25 0.00
50.00 6.80 3.25 0.00 154.00 6.80 3.25 0.00
52.00 6.80 3.25 0.00 156.00 6.80 3.25 0.00
54.00 6.80 3.25 0.00 158.00 6.80 3.25 0.00
56.00 6.80 3.25 0.00 160.00 6.80 3.25 0.00
58.00 6.80 3.25 0.00 162.00 6.80 3.25 0.00
60.00 6.80 3.25 0.00 164.00 6.80 3.25 0.00
62.00 6.80 3.25 0.00 166.00 6.80 3.25 0.00
64.00 6.80 3.25 0.00 168.00 6.80 3.25 0.00
66.00 6.80 3.25 0.00 170.00 6.80 3.25 0.00
68.00 6.80 3.25 0.00 172.00 6.80 3.25 0.00
70.00 6.80 3.25 0.00 174.00 6.80 3.25 0.00
72.00 6.80 3.25 0.00 176.00 6.80 3.25 0.00
74.00 6.80 3.25 0.00 178.00 6.80 3.25 0.00
76.00 6.80 3.25 0.00 180.00 6.80 3.25 0.00
78.00 6.80 3.25 0.00 182.00 6.80 3.25 0.00
80.00 6.80 3.25 0.00 184.00 6.80 3.25 0.00
82.00 6.80 3.25 0.00 186.00 6.80 3.25 0.00
84.00 6.80 3.25 0.00 188.00 6.80 3.25 0.00
86.00 6.80 3.25 0.00 190.00 6.80 3.25 0.00
88.00 6.80 3.25 0.00 192.00 6.80 3.25 0.00
90.00 6.80 3.25 0.00 194.00 6.80 3.25 0.00
92.00 6.80 3.25 0.00 196.00 6.80 3.25 0.00
94.00 6.80 3.25 0.00 198.00 6.80 3.25 0.00
96.00 6.80 3.25 0.00 200.00 6.80 3.25 0.00
98.00 6.80 3.25 0.00
100.00 6.80 3.25 0.00
102.00 6.80 3.25 0.00

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Subcatchment 2S: (Post Developed)
Runoff = 85.12 cfs @ 11.96 hrs, Volume= 3.976 af, Depth= 4.62"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
4.430 98 Paved parking & roofs
5.900 69 50-75% Grass cover, Fair, HSG B
10.330 81 Weighted Average
5.900 Pervious Area
4.430 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 4.62 0.00
2.00 0.15 0.00 0.00 106.00 6.80 4.62 0.00
4.00 0.33 0.00 0.00 108.00 6.80 4.62 0.00
6.00 0.54 0.00 0.07 110.00 6.80 4.62 0.00
8.00 0.82 0.04 0.36 112.00 6.80 4.62 0.00
10.00 1.23 0.19 1.16 114.00 6.80 4.62 0.00
12.00 4.51 2.56 71.80 116.00 6.80 4.62 0.00
14.00 5.58 3.50 2.46 118.00 6.80 4.62 0.00
16.00 5.98 3.87 1.52 120.00 6.80 4.62 0.00
18.00 6.26 4.12 1.18 122.00 6.80 4.62 0.00
20.00 6.47 4.32 0.86 124.00 6.80 4.62 0.00
22.00 6.64 4.47 0.79 126.00 6.80 4.62 0.00
24.00 6.80 4.62 0.72 128.00 6.80 4.62 0.00
26.00 6.80 4.62 0.00 130.00 6.80 4.62 0.00
28.00 6.80 4.62 0.00 132.00 6.80 4.62 0.00
30.00 6.80 4.62 0.00 134.00 6.80 4.62 0.00
32.00 6.80 4.62 0.00 136.00 6.80 4.62 0.00
34.00 6.80 4.62 0.00 138.00 6.80 4.62 0.00
36.00 6.80 4.62 0.00 140.00 6.80 4.62 0.00
38.00 6.80 4.62 0.00 142.00 6.80 4.62 0.00
40.00 6.80 4.62 0.00 144.00 6.80 4.62 0.00
42.00 6.80 4.62 0.00 146.00 6.80 4.62 0.00
44.00 6.80 4.62 0.00 148.00 6.80 4.62 0.00
46.00 6.80 4.62 0.00 150.00 6.80 4.62 0.00
48.00 6.80 4.62 0.00 152.00 6.80 4.62 0.00
50.00 6.80 4.62 0.00 154.00 6.80 4.62 0.00
52.00 6.80 4.62 0.00 156.00 6.80 4.62 0.00
54.00 6.80 4.62 0.00 158.00 6.80 4.62 0.00
56.00 6.80 4.62 0.00 160.00 6.80 4.62 0.00
58.00 6.80 4.62 0.00 162.00 6.80 4.62 0.00
60.00 6.80 4.62 0.00 164.00 6.80 4.62 0.00
62.00 6.80 4.62 0.00 166.00 6.80 4.62 0.00
64.00 6.80 4.62 0.00 168.00 6.80 4.62 0.00
66.00 6.80 4.62 0.00 170.00 6.80 4.62 0.00
68.00 6.80 4.62 0.00 172.00 6.80 4.62 0.00
70.00 6.80 4.62 0.00 174.00 6.80 4.62 0.00
72.00 6.80 4.62 0.00 176.00 6.80 4.62 0.00
74.00 6.80 4.62 0.00 178.00 6.80 4.62 0.00
76.00 6.80 4.62 0.00 180.00 6.80 4.62 0.00
78.00 6.80 4.62 0.00 182.00 6.80 4.62 0.00
80.00 6.80 4.62 0.00 184.00 6.80 4.62 0.00
82.00 6.80 4.62 0.00 186.00 6.80 4.62 0.00
84.00 6.80 4.62 0.00 188.00 6.80 4.62 0.00
86.00 6.80 4.62 0.00 190.00 6.80 4.62 0.00
88.00 6.80 4.62 0.00 192.00 6.80 4.62 0.00
90.00 6.80 4.62 0.00 194.00 6.80 4.62 0.00
92.00 6.80 4.62 0.00 196.00 6.80 4.62 0.00
94.00 6.80 4.62 0.00 198.00 6.80 4.62 0.00
96.00 6.80 4.62 0.00 200.00 6.80 4.62 0.00
98.00 6.80 4.62 0.00
100.00 6.80 4.62 0.00
102.00 6.80 4.62 0.00

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Pond 3P: (BMP2)
Inflow Area = 10.330 ac, Inflow Depth = 4.62" for 50-yr Concord event
Inflow = 85.12 cfs @ 11.96 hrs, Volume= 3.976 af
Outflow = 24.17 cfs @ 12.08 hrs, Volume= 3.975 af, Atten= 72%, Lag= 7.1 min
Primary = 24.17 cfs @ 12.08 hrs, Volume= 3.975 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 636.82' @ 12.08 hrs Surf.Area= 23,464 sf Storage= 85,431 cf
Plug-Flow detention time= 710.0 min calculated for 3.975 af(100% of inflow)
Center-of-Mass det. time= 709.7 min ( 1,512.3 - 802.6 )
Volume Invert Avail.Storage Storage Description
#1 632.50' 114,317 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
632.50 15,777 0 0
634.00 18,796 25,930 25,930
636.00 22,040 40,836 66,766
638.00 25,511 47,551 114,317
Device Routing Invert Outlet Devices
#1 Primary 628.00' 18.0" x 106.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 617.77' S= 0.0965 '/' Cc= 0.900 n= 0.012
#2 Device 1 632.50' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.158 0.221 0.284 0.347 0.410 0.473
#3 Device 1 634.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=24.17 cfs @ 12.08 hrs HW=636.82' (Free Discharge)
t-1=Culvert (Inlet Controls 24.17 cfs @ 13.68 fps)
2=Exfiltration (Passes < 0.37 cfs potential flow)
3=Orifice/Grate (Passes < 1.52 cfs potential flow)
4=Top of Riser (Passes < 24.27 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=632.50' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Hydrograph for Pond 3P: (BMP2)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 632.50 0.00 0.00 0.00
5.00 0.00 0 632.50 0.00 0.00 0.00
10.00 1.16 6,375 632.89 0.06 0.06 0.00
15.00 1.96 68,228 636.07 2.19 2.19 0.00
20.00 0.86 62,034 635.78 1.47 1.47 0.00
25.00 0.00 49,284 635.18 1.18 1.18 0.00
30.00 0.00 33,404 634.39 0.56 0.56 0.00
35.00 0.00 27,353 634.08 0.21 0.21 0.00
40.00 0.00 23,910 633.89 0.18 0.18 0.00
45.00 0.00 20,720 633.72 0.17 0.17 0.00
50.00 0.00 17,723 633.55 0.16 0.16 0.00
55.00 0.00 14,969 633.40 0.14 0.14 0.00
60.00 0.00 12,614 633.26 0.12 0.12 0.00
65.00 0.00 10,615 633.15 0.10 0.10 0.00
70.00 0.00 8,923 633.05 0.09 0.09 0.00
75.00 0.00 7,493 632.96 0.07 0.07 0.00
80.00 0.00 6,287 632.89 0.06 0.06 0.00
85.00 0.00 5,271 632.83 0.05 0.05 0.00
90.00 0.00 4,417 632.78 0.04 0.04 0.00
95.00 0.00 3,699 632.73 0.04 0.04 0.00
100.00 0.00 3,096 632.69 0.03 0.03 0.00
105.00 0.00 2,591 632.66 0.03 0.03 0.00
110.00 0.00 2,167 632.64 0.02 0.02 0.00
115.00 0.00 1,812 632.61 0.02 0.02 0.00
120.00 0.00 1,515 632.60 0.02 0.02 0.00
125.00 0.00 1,267 632.58 0.01 0.01 0.00
130.00 0.00 1,059 632.57 0.01 0.01 0.00
135.00 0.00 885 632.56 0.01 0.01 0.00
140.00 0.00 739 632.55 0.01 0.01 0.00
145.00 0.00 618 632.54 0.01 0.01 0.00
150.00 0.00 516 632.53 0.01 0.01 0.00
155.00 0.00 431 632.53 0.00 0.00 0.00
160.00 0.00 361 632.52 0.00 0.00 0.00
165.00 0.00 301 632.52 0.00 0.00 0.00
170.00 0.00 252 632.52 0.00 0.00 0.00
175.00 0.00 210 632.51 0.00 0.00 0.00
180.00 0.00 176 632.51 0.00 0.00 0.00
185.00 0.00 147 632.51 0.00 0.00 0.00
190.00 0.00 123 632.51 0.00 0.00 0.00
195.00 0.00 103 632.51 0.00 0.00 0.00
200.00 0.00 86 632.51 0.00 0.00 0.00

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Discharge for Pond 3P: (BMP2)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
632.50 0.00 0.00 0.00 637.70 41.09 25.46 15.64
632.60 0.02 0.02 0.00 637.80 44.49 25.60 18.89
632.70 0.03 0.03 0.00 637.90 48.24 25.74 22.50
632.80 0.05 0.05 0.00 638.00 52.18 25.88 26.30
632.90 0.06 0.06 0.00 638.10 56.42 26.02 30.40
633.00 0.08 0.08 0.00 638.20 60.86 26.16 34.70
633.10 0.09 0.09 0.00 638.30 65.43 26.29 39.13
633.20 0.11 0.11 0.00 638.40 70.16 26.43 43.73
633.30 0.13 0.13 0.00 638.50 74.98 26.57 48.41
633.40 0.14 0.14 0.00
633.50 0.16 0.16 0.00
633.60 0.16 0.16 0.00
633.70 0.17 0.17 0.00
633.80 0.18 0.18 0.00
633.90 0.18 0.18 0.00
634.00 0.19 0.19 0.00
634.10 0.23 0.23 0.00
634.20 0.31 0.31 0.00
634.30 0.44 0.44 0.00
634.40 0.58 0.58 0.00
634.50 0.69 0.69 0.00
634.60 0.79 0.79 0.00
634.70 0.87 0.87 0.00
634.80 0.94 0.94 0.00
634.90 1.01 1.01 0.00
635.00 1.07 1.07 0.00
635.10 1.13 1.13 0.00
635.20 1.19 1.19 0.00
635.30 1.24 1.24 0.00
635.40 1.29 1.29 0.00
635.50 1.34 1.34 0.00
635.60 1.39 1.39 0.00
635.70 1.44 1.44 0.00
635.80 1.48 1.48 0.00
635.90 1.52 1.52 0.00
636.00 1.57 1.57 0.00
636.10 2.64 2.64 0.00
636.20 4.57 4.57 0.00
636.30 7.06 7.06 0.00
636.40 10.00 10.00 0.00
636.50 13.33 13.33 0.00
636.60 17.00 17.00 0.00
636.70 20.99 20.99 0.00
636.80 24.14 24.14 0.00
636.90 24.29 24.29 0.00
637.00 24.44 24.44 0.00
637.10 25.43 24.59 0.85
637.20 27.13 24.73 2.40
637.30 29.30 24.88 4.42
637.40 31.86 25.03 6.83
637.50 34.72 25.17 9.55
637.60 37.86 25.31 12.55

2020.17-BMP2 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 2/7/2023
Stage-Area-Storage for Pond 3P: (BMP2)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
632.50 15,777 0 637.70 24,990 106,742
632.60 15,978 1,588 637.80 25,164 109,249
632.70 16,180 3,196 637.90 25,337 111,774
632.80 16,381 4,824 638.00 25,511 114,317
632.90 16,582 6,472 638.10 25,511 114,317
633.00 16,783 8,140 638.20 25,511 114,317
633.10 16,985 9,828 638.30 25,511 114,317
633.20 17,186 11,537 638.40 25,511 114,317
633.30 17,387 13,266 638.50 25,511 114,317
633.40 17,588 15,014
633.50 17,790 16,783
633.60 17,991 18,572
633.70 18,192 20,382
633.80 18,393 22,211
633.90 18,595 24,060
634.00 18,796 25,930
634.10 18,958 27,817
634.20 19,120 29,721
634.30 19,283 31,642
634.40 19,445 33,578
634.50 19,607 35,531
634.60 19,769 37,499
634.70 19,931 39,484
634.80 20,094 41,486
634.90 20,256 43,503
635.00 20,418 45,537
635.10 20,580 47,587
635.20 20,742 49,653
635.30 20,905 51,735
635.40 21,067 53,834
635.50 21,229 55,949
635.60 21,391 58,080
635.70 21,553 60,227
635.80 21,716 62,390
635.90 21,878 64,570
636.00 22,040 66,766
636.10 22,214 68,978
636.20 22,387 71,208
636.30 22,561 73,456
636.40 22,734 75,721
636.50 22,908 78,003
636.60 23,081 80,302
636.70 23,255 82,619
636.80 23,428 84,953
636.90 23,602 87,305
637.00 23,776 89,674
637.10 23,949 92,060
637.20 24,123 94,463
637.30 24,296 96,884
637.40 24,470 99,323
637.50 24,643 101,778
637.60 24,817 104,251

SAND FILTER-3
7-/- ..
1 __ '.. - / .3 A-1-1‘
((::: "\-:-.
ll
I .1
I/ k �._-
T628
��
)
Iy, / 1 *• =`� �r�,
/( �O C (O r a.t4 n5 en')
,—.- -1- ,2 l'' .02" , • • 03
--s
�I r j e � J i
I/ / !r. �.. ' - )
i
- /
/1 ‘ r 4 NV.OW?424.42
•
:(12 .o.^'.'''''7'7, -1:77//:/-7-.". #:'
•
a wv-NY Ph�t1.10 111
Off INLr+ -
)/ P 7'
4' ''''..:7

Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 3
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 8.87 ac
Impervious area to filter forebay= 3.94 ac.
Impervious percentage= 44.41%
Rv=0.05+0.9(la) = 0.44971657
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 14480 cf (used to size Af)
WQV= 0.3324 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
628 9379 0 0
629 10574 9976.5 9976.5
630 11768 11171 21147.5
631 13075 12421.5 33569
632 14381 13728 47297
633 15802 15091.5 62388.5
634 17222 16512 78900.5
Calculate Depth for WQ Volume:
628 0
629.37 14480
630 21147.5
Elevation of WQ Volume= 629.37
3. Discount WQv:
0.75 x WQv 10860.01 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 72.0
Cn Post= 83.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 4.12 18.73 25.90 69.25
Post. Dev. 21.48 50.96 63.37 155.68
Routed 0.60 7.70 26.51 93.04
Peak Stage 630.23 632.32 632.83 615.27
Disch.Time 95 hours 0.73' Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
1810 SA(ft2) Dv"12
2 FS SA = FS" K"T
10860 DV(FT3) where: SA =required minimum surface area of infiltration system(fK)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(10)
K =hydraulic conductivity of soil(in/hr)
72 T(hours) T =maximum dewatering time(72 hours)
6.Sediment Sand Sizing
10860 Design Volume(ft3)
5430 Sediment Chamber(ft3)
5430 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 301.6671 cf/hour 0.084 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
100 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 1600 holes
50%of perforations= 800 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 6.64 cfs which is 79.2 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
Dimensions of Riser
7.4 Height of Riser,ft. 2 ft L
6 Area of Riser,s.f. 3 ft W
44.4 Volume of Riser,c.f. 0.5 ft
2770.56 Weight of Water @ 62.4 pcf
3047.616 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
1.37 Volume of Concrete Req'd in c.y.
36.90 Volume of Concrete Req'd in c.f.
44.4 Volume of Concrete in Structure(cf)
-7.50 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
1 ft thick
1.9 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 1810 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 12066.68 0.140
2 16893.36 0.196
3 21720.03 0.251
4 26546.7 0.307
5 31373.37 0.363
6 36200.05 0.419
7 41026.72 0.475
8 45853.39 0.531
9 50680.07 0.587
10 55506.74 0.642

41,
(Predeveloped)
e > 3P
(Post Developed) (BMP3)
(Subcat Reach 'On. MI Drainage Diagram for 2020.17-BMP3
Prepared by{enter your company name here} 1/23/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP3
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
4.340 60 Woods, Fair, HSG B (1S)
4.930 69 50-75% Grass cover, Fair, HSG B (2S)
2.540 69 Pasture/grassland/range, Fair, HSG B (1S)
0.900 73 Woods, Fair, HSG C (1S)
1.090 79 Pasture/grassland/range, Fair, HSG C (1S)
3.940 98 Paved parking & roofs (2S)
17.740

2020.17-BMP3 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.870 ac Runoff Depth=0.50"
Flow Length=568' Tc=17.1 min CN=66 Runoff=4.12 cfs 0.368 af
Subcatchment 2S: (Post Developed) Runoff Area=8.870 ac Runoff Depth=1.30"
Tc=5.0 min CN=82 Runoff=21.48 cfs 0.961 af
Pond 3P: (BMP3) Peak Elev=630.42' Storage=26,178 cf Inflow=21.48 cfs 0.961 af
Primary=0.60 cfs 0.961 af Secondary=0.00 cfs 0.000 af Outflow=0.60 cfs 0.961 af
Total Runoff Area = 17.740 ac Runoff Volume = 1.329 af Average Runoff Depth = 0.90"
77.79% Pervious Area = 13.800 ac 22.21% Impervious Area = 3.940 ac

2020.17-BMP3 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 4.12 cfs @ 12.13 hrs, Volume= 0.368 af, Depth= 0.50"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.340 60 Woods, Fair, HSG B
0.900 73 Woods, Fair, HSG C
1.090 79 Pasture/grassland/range, Fair, HSG C
2.540 69 Pasture/grassland/range, Fair, HSG B
8.870 66 Weighted Average
8.870 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.8 100 0.0288 0.14 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
5.3 468 0.0880 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
17.1 568 Total

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.50 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.50 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.50 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.50 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.50 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.50 0.00
12.00 1.92 0.13 2.00 116.00 2.90 0.50 0.00
14.00 2.38 0.28 0.40 118.00 2.90 0.50 0.00
16.00 2.55 0.35 0.26 120.00 2.90 0.50 0.00
18.00 2.67 0.40 0.20 122.00 2.90 0.50 0.00
20.00 2.76 0.44 0.16 124.00 2.90 0.50 0.00
22.00 2.83 0.47 0.14 126.00 2.90 0.50 0.00
24.00 2.90 0.50 0.13 128.00 2.90 0.50 0.00
26.00 2.90 0.50 0.00 130.00 2.90 0.50 0.00
28.00 2.90 0.50 0.00 132.00 2.90 0.50 0.00
30.00 2.90 0.50 0.00 134.00 2.90 0.50 0.00
32.00 2.90 0.50 0.00 136.00 2.90 0.50 0.00
34.00 2.90 0.50 0.00 138.00 2.90 0.50 0.00
36.00 2.90 0.50 0.00 140.00 2.90 0.50 0.00
38.00 2.90 0.50 0.00 142.00 2.90 0.50 0.00
40.00 2.90 0.50 0.00 144.00 2.90 0.50 0.00
42.00 2.90 0.50 0.00 146.00 2.90 0.50 0.00
44.00 2.90 0.50 0.00 148.00 2.90 0.50 0.00
46.00 2.90 0.50 0.00 150.00 2.90 0.50 0.00
48.00 2.90 0.50 0.00 152.00 2.90 0.50 0.00
50.00 2.90 0.50 0.00 154.00 2.90 0.50 0.00
52.00 2.90 0.50 0.00 156.00 2.90 0.50 0.00
54.00 2.90 0.50 0.00 158.00 2.90 0.50 0.00
56.00 2.90 0.50 0.00 160.00 2.90 0.50 0.00
58.00 2.90 0.50 0.00 162.00 2.90 0.50 0.00
60.00 2.90 0.50 0.00 164.00 2.90 0.50 0.00
62.00 2.90 0.50 0.00 166.00 2.90 0.50 0.00
64.00 2.90 0.50 0.00 168.00 2.90 0.50 0.00
66.00 2.90 0.50 0.00 170.00 2.90 0.50 0.00
68.00 2.90 0.50 0.00 172.00 2.90 0.50 0.00
70.00 2.90 0.50 0.00 174.00 2.90 0.50 0.00
72.00 2.90 0.50 0.00 176.00 2.90 0.50 0.00
74.00 2.90 0.50 0.00 178.00 2.90 0.50 0.00
76.00 2.90 0.50 0.00 180.00 2.90 0.50 0.00
78.00 2.90 0.50 0.00 182.00 2.90 0.50 0.00
80.00 2.90 0.50 0.00 184.00 2.90 0.50 0.00
82.00 2.90 0.50 0.00 186.00 2.90 0.50 0.00
84.00 2.90 0.50 0.00 188.00 2.90 0.50 0.00
86.00 2.90 0.50 0.00 190.00 2.90 0.50 0.00
88.00 2.90 0.50 0.00 192.00 2.90 0.50 0.00
90.00 2.90 0.50 0.00 194.00 2.90 0.50 0.00
92.00 2.90 0.50 0.00 196.00 2.90 0.50 0.00
94.00 2.90 0.50 0.00 198.00 2.90 0.50 0.00
96.00 2.90 0.50 0.00 200.00 2.90 0.50 0.00
98.00 2.90 0.50 0.00
100.00 2.90 0.50 0.00
102.00 2.90 0.50 0.00

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 21.48 cfs @ 11.96 hrs, Volume= 0.961 af, Depth= 1.30"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
3.940 98 Paved parking & roofs
4.930 69 50-75% Grass cover, Fair, HSG B
8.870 82 Weighted Average
4.930 Pervious Area
3.940 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.30 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.30 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.30 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.30 0.00
8.00 0.35 0.00 0.00 112.00 2.90 1.30 0.00
10.00 0.52 0.00 0.07 114.00 2.90 1.30 0.00
12.00 1.92 0.60 18.69 116.00 2.90 1.30 0.00
14.00 2.38 0.91 0.72 118.00 2.90 1.30 0.00
16.00 2.55 1.04 0.45 120.00 2.90 1.30 0.00
18.00 2.67 1.13 0.36 122.00 2.90 1.30 0.00
20.00 2.76 1.19 0.26 124.00 2.90 1.30 0.00
22.00 2.83 1.25 0.24 126.00 2.90 1.30 0.00
24.00 2.90 1.30 0.22 128.00 2.90 1.30 0.00
26.00 2.90 1.30 0.00 130.00 2.90 1.30 0.00
28.00 2.90 1.30 0.00 132.00 2.90 1.30 0.00
30.00 2.90 1.30 0.00 134.00 2.90 1.30 0.00
32.00 2.90 1.30 0.00 136.00 2.90 1.30 0.00
34.00 2.90 1.30 0.00 138.00 2.90 1.30 0.00
36.00 2.90 1.30 0.00 140.00 2.90 1.30 0.00
38.00 2.90 1.30 0.00 142.00 2.90 1.30 0.00
40.00 2.90 1.30 0.00 144.00 2.90 1.30 0.00
42.00 2.90 1.30 0.00 146.00 2.90 1.30 0.00
44.00 2.90 1.30 0.00 148.00 2.90 1.30 0.00
46.00 2.90 1.30 0.00 150.00 2.90 1.30 0.00
48.00 2.90 1.30 0.00 152.00 2.90 1.30 0.00
50.00 2.90 1.30 0.00 154.00 2.90 1.30 0.00
52.00 2.90 1.30 0.00 156.00 2.90 1.30 0.00
54.00 2.90 1.30 0.00 158.00 2.90 1.30 0.00
56.00 2.90 1.30 0.00 160.00 2.90 1.30 0.00
58.00 2.90 1.30 0.00 162.00 2.90 1.30 0.00
60.00 2.90 1.30 0.00 164.00 2.90 1.30 0.00
62.00 2.90 1.30 0.00 166.00 2.90 1.30 0.00
64.00 2.90 1.30 0.00 168.00 2.90 1.30 0.00
66.00 2.90 1.30 0.00 170.00 2.90 1.30 0.00
68.00 2.90 1.30 0.00 172.00 2.90 1.30 0.00
70.00 2.90 1.30 0.00 174.00 2.90 1.30 0.00
72.00 2.90 1.30 0.00 176.00 2.90 1.30 0.00
74.00 2.90 1.30 0.00 178.00 2.90 1.30 0.00
76.00 2.90 1.30 0.00 180.00 2.90 1.30 0.00
78.00 2.90 1.30 0.00 182.00 2.90 1.30 0.00
80.00 2.90 1.30 0.00 184.00 2.90 1.30 0.00
82.00 2.90 1.30 0.00 186.00 2.90 1.30 0.00
84.00 2.90 1.30 0.00 188.00 2.90 1.30 0.00
86.00 2.90 1.30 0.00 190.00 2.90 1.30 0.00
88.00 2.90 1.30 0.00 192.00 2.90 1.30 0.00
90.00 2.90 1.30 0.00 194.00 2.90 1.30 0.00
92.00 2.90 1.30 0.00 196.00 2.90 1.30 0.00
94.00 2.90 1.30 0.00 198.00 2.90 1.30 0.00
96.00 2.90 1.30 0.00 200.00 2.90 1.30 0.00
98.00 2.90 1.30 0.00
100.00 2.90 1.30 0.00
102.00 2.90 1.30 0.00

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP3)
Inflow Area = 8.870 ac, Inflow Depth = 1.30" for 1-yr Concord event
Inflow = 21.48 cfs @ 11.96 hrs, Volume= 0.961 af
Outflow = 0.60 cfs @ 14.79 hrs, Volume= 0.961 af, Atten= 97%, Lag= 169.8 min
Primary = 0.60 cfs @ 14.79 hrs, Volume= 0.961 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 630.42' @ 14.79 hrs Surf.Area= 12,314 sf Storage= 26,178 cf
Plug-Flow detention time= 1,181.1 min calculated for 0.961 of(100% of inflow)
Center-of-Mass det. time= 1,181.5 min ( 2,018.5 - 836.9 )
Volume Invert Avail.Storage Storage Description _
#1 628.00' 78,899 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
628.00 9,379 0 0
630.00 11,768 21,147 21,147
632.00 14,381 26,149 47,296
634.00 17,222 31,603 78,899
Device Routing Invert Outlet Devices
#1 Primary 614.18' 18.0" x 30.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 614.00' S= 0.0060 '/' Cc= 0.900 n= 0.013
#2 Device 1 628.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.140 0.196 0.251 0.307 0.363 0.419
#3 Device 1 630.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 632.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 633.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=0.60 cfs @ 14.79 hrs HW=630.42' (Free Discharge)
t-1=Culvert (Passes 0.60 cfs of 33.49 cfs potential flow)
2=Exfiltration (Custom Controls 0.22 cfs)
3=Orifice/Grate (Orifice Controls 0.39 cfs @ 2.20 fps)
4=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=628.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP3)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 628.00 0.00 0.00 0.00
5.00 0.00 0 628.00 0.00 0.00 0.00
10.00 0.07 83 628.01 0.00 0.00 0.00
15.00 0.58 26,169 630.42 0.60 0.60 0.00
20.00 0.26 24,167 630.25 0.38 0.38 0.00
25.00 0.00 22,183 630.09 0.23 0.23 0.00
30.00 0.00 18,676 629.79 0.18 0.18 0.00
35.00 0.00 15,504 629.51 0.17 0.17 0.00
40.00 0.00 12,606 629.25 0.15 0.15 0.00
45.00 0.00 9,964 629.00 0.14 0.14 0.00
50.00 0.00 7,727 628.78 0.11 0.11 0.00
55.00 0.00 5,974 628.61 0.09 0.09 0.00
60.00 0.00 4,608 628.48 0.07 0.07 0.00
65.00 0.00 3,547 628.37 0.05 0.05 0.00
70.00 0.00 2,726 628.29 0.04 0.04 0.00
75.00 0.00 2,093 628.22 0.03 0.03 0.00
80.00 0.00 1,605 628.17 0.02 0.02 0.00
85.00 0.00 1,230 628.13 0.02 0.02 0.00
90.00 0.00 942 628.10 0.01 0.01 0.00
95.00 0.00 721 628.08 0.01 0.01 0.00
100.00 0.00 552 628.06 0.01 0.01 0.00
105.00 0.00 422 628.04 0.01 0.01 0.00
110.00 0.00 323 628.03 0.00 0.00 0.00
115.00 0.00 247 628.03 0.00 0.00 0.00
120.00 0.00 189 628.02 0.00 0.00 0.00
125.00 0.00 145 628.02 0.00 0.00 0.00
130.00 0.00 111 628.01 0.00 0.00 0.00
135.00 0.00 85 628.01 0.00 0.00 0.00
140.00 0.00 65 628.01 0.00 0.00 0.00
145.00 0.00 50 628.01 0.00 0.00 0.00
150.00 0.00 38 628.00 0.00 0.00 0.00
155.00 0.00 29 628.00 0.00 0.00 0.00
160.00 0.00 22 628.00 0.00 0.00 0.00
165.00 0.00 17 628.00 0.00 0.00 0.00
170.00 0.00 13 628.00 0.00 0.00 0.00
175.00 0.00 10 628.00 0.00 0.00 0.00
180.00 0.00 8 628.00 0.00 0.00 0.00
185.00 0.00 6 628.00 0.00 0.00 0.00
190.00 0.00 4 628.00 0.00 0.00 0.00
195.00 0.00 3 628.00 0.00 0.00 0.00
200.00 0.00 3 628.00 0.00 0.00 0.00

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP3)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
628.00 0.00 0.00 0.00 633.20 36.04 33.65 2.40
628.10 0.01 0.01 0.00 633.30 39.39 34.97 4.42
628.20 0.03 0.03 0.00 633.40 43.08 36.25 6.83
628.30 0.04 0.04 0.00 633.50 46.21 36.67 9.55
628.40 0.06 0.06 0.00 633.60 49.31 36.77 12.55
628.50 0.07 0.07 0.00 633.70 52.50 36.86 15.64
628.60 0.08 0.08 0.00 633.80 55.85 36.96 18.89
628.70 0.10 0.10 0.00 633.90 59.56 37.06 22.50
628.80 0.11 0.11 0.00 634.00 63.46 37.16 26.30
628.90 0.13 0.13 0.00
629.00 0.14 0.14 0.00
629.10 0.15 0.15 0.00
629.20 0.15 0.15 0.00
629.30 0.16 0.16 0.00
629.40 0.16 0.16 0.00
629.50 0.17 0.17 0.00
629.60 0.17 0.17 0.00
629.70 0.18 0.18 0.00
629.80 0.18 0.18 0.00
629.90 0.19 0.19 0.00
630.00 0.20 0.20 0.00
630.10 0.23 0.23 0.00
630.20 0.32 0.32 0.00
630.30 0.44 0.44 0.00
630.40 0.58 0.58 0.00
630.50 0.70 0.70 0.00
630.60 0.79 0.79 0.00
630.70 0.87 0.87 0.00
630.80 0.94 0.94 0.00
630.90 1.01 1.01 0.00
631.00 1.07 1.07 0.00
631.10 1.13 1.13 0.00
631.20 1.18 1.18 0.00
631.30 1.24 1.24 0.00
631.40 1.29 1.29 0.00
631.50 1.34 1.34 0.00
631.60 1.38 1.38 0.00
631.70 1.43 1.43 0.00
631.80 1.47 1.47 0.00
631.90 1.52 1.52 0.00
632.00 1.56 1.56 0.00
632.10 2.63 2.63 0.00
632.20 4.56 4.56 0.00
632.30 7.05 7.05 0.00
632.40 9.99 9.99 0.00
632.50 13.31 13.31 0.00
632.60 16.99 16.99 0.00
632.70 20.98 20.98 0.00
632.80 25.26 25.26 0.00
632.90 29.30 29.30 0.00
633.00 30.82 30.82 0.00
633.10 33.11 32.26 0.85

2020.17-BMP3 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP3)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
628.00 9,379 0 633.20 16,086 65,576
628.10 9,498 944 633.30 16,228 67,192
628.20 9,618 1,900 633.40 16,370 68,821
628.30 9,737 2,867 633.50 16,512 70,466
628.40 9,857 3,847 633.60 16,654 72,124
628.50 9,976 4,839 633.70 16,796 73,796
628.60 10,096 5,842 633.80 16,938 75,483
628.70 10,215 6,858 633.90 17,080 77,184
628.80 10,335 7,885 634.00 17,222 78,899
628.90 10,454 8,925
629.00 10,574 9,976
629.10 10,693 11,040
629.20 10,812 12,115
629.30 10,932 13,202
629.40 11,051 14,301
629.50 11,171 15,412
629.60 11,290 16,535
629.70 11,410 17,670
629.80 11,529 18,817
629.90 11,649 19,976
630.00 11,768 21,147
630.10 11,899 22,330
630.20 12,029 23,527
630.30 12,160 24,736
630.40 12,291 25,959
630.50 12,421 27,194
630.60 12,552 28,443
630.70 12,683 29,705
630.80 12,813 30,979
630.90 12,944 32,267
631.00 13,075 33,568
631.10 13,205 34,882
631.20 13,336 36,209
631.30 13,466 37,549
631.40 13,597 38,903
631.50 13,728 40,269
631.60 13,858 41,648
631.70 13,989 43,040
631.80 14,120 44,446
631.90 14,250 45,864
632.00 14,381 47,296
632.10 14,523 48,741
632.20 14,665 50,201
632.30 14,807 51,674
632.40 14,949 53,162
632.50 15,091 54,664
632.60 15,233 56,180
632.70 15,375 57,711
632.80 15,517 59,255
632.90 15,659 60,814
633.00 15,802 62,387
633.10 15,944 63,975

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.870 ac Runoff Depth=1.80"
Flow Length=568' Tc=17.1 min CN=66 Runoff=18.73 cfs 1.328 af
Subcatchment 2S: (Post Developed) Runoff Area=8.870 ac Runoff Depth=3.17"
Tc=5.0 min CN=82 Runoff=50.96 cfs 2.342 af
Pond 3P: (BMP3) Peak Elev=632.32' Storage=51,994 cf Inflow=50.96 cfs 2.342 af
Primary=7.65 cfs 2.342 af Secondary=0.00 cfs 0.000 af Outflow=7.65 cfs 2.342 af
Total Runoff Area = 17.740 ac Runoff Volume = 3.670 af Average Runoff Depth = 2.48"
77.79% Pervious Area = 13.800 ac 22.21% Impervious Area = 3.940 ac

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 18.73 cfs @ 12.10 hrs, Volume= 1.328 af, Depth= 1.80"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
4.340 60 Woods, Fair, HSG B
0.900 73 Woods, Fair, HSG C
1.090 79 Pasture/grassland/range, Fair, HSG C
2.540 69 Pasture/grassland/range, Fair, HSG B
8.870 66 Weighted Average
8.870 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.8 100 0.0288 0.14 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
5.3 468 0.0880 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
17.1 568 Total

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 1.80 0.00
2.00 0.11 0.00 0.00 106.00 5.10 1.80 0.00
4.00 0.24 0.00 0.00 108.00 5.10 1.80 0.00
6.00 0.41 0.00 0.00 110.00 5.10 1.80 0.00
8.00 0.61 0.00 0.00 112.00 5.10 1.80 0.00
10.00 0.92 0.00 0.00 114.00 5.10 1.80 0.00
12.00 3.38 0.74 12.99 116.00 5.10 1.80 0.00
14.00 4.18 1.20 1.18 118.00 5.10 1.80 0.00
16.00 4.49 1.39 0.72 120.00 5.10 1.80 0.00
18.00 4.70 1.52 0.56 122.00 5.10 1.80 0.00
20.00 4.86 1.63 0.42 124.00 5.10 1.80 0.00
22.00 4.98 1.72 0.38 126.00 5.10 1.80 0.00
24.00 5.10 1.80 0.35 128.00 5.10 1.80 0.00
26.00 5.10 1.80 0.00 130.00 5.10 1.80 0.00
28.00 5.10 1.80 0.00 132.00 5.10 1.80 0.00
30.00 5.10 1.80 0.00 134.00 5.10 1.80 0.00
32.00 5.10 1.80 0.00 136.00 5.10 1.80 0.00
34.00 5.10 1.80 0.00 138.00 5.10 1.80 0.00
36.00 5.10 1.80 0.00 140.00 5.10 1.80 0.00
38.00 5.10 1.80 0.00 142.00 5.10 1.80 0.00
40.00 5.10 1.80 0.00 144.00 5.10 1.80 0.00
42.00 5.10 1.80 0.00 146.00 5.10 1.80 0.00
44.00 5.10 1.80 0.00 148.00 5.10 1.80 0.00
46.00 5.10 1.80 0.00 150.00 5.10 1.80 0.00
48.00 5.10 1.80 0.00 152.00 5.10 1.80 0.00
50.00 5.10 1.80 0.00 154.00 5.10 1.80 0.00
52.00 5.10 1.80 0.00 156.00 5.10 1.80 0.00
54.00 5.10 1.80 0.00 158.00 5.10 1.80 0.00
56.00 5.10 1.80 0.00 160.00 5.10 1.80 0.00
58.00 5.10 1.80 0.00 162.00 5.10 1.80 0.00
60.00 5.10 1.80 0.00 164.00 5.10 1.80 0.00
62.00 5.10 1.80 0.00 166.00 5.10 1.80 0.00
64.00 5.10 1.80 0.00 168.00 5.10 1.80 0.00
66.00 5.10 1.80 0.00 170.00 5.10 1.80 0.00
68.00 5.10 1.80 0.00 172.00 5.10 1.80 0.00
70.00 5.10 1.80 0.00 174.00 5.10 1.80 0.00
72.00 5.10 1.80 0.00 176.00 5.10 1.80 0.00
74.00 5.10 1.80 0.00 178.00 5.10 1.80 0.00
76.00 5.10 1.80 0.00 180.00 5.10 1.80 0.00
78.00 5.10 1.80 0.00 182.00 5.10 1.80 0.00
80.00 5.10 1.80 0.00 184.00 5.10 1.80 0.00
82.00 5.10 1.80 0.00 186.00 5.10 1.80 0.00
84.00 5.10 1.80 0.00 188.00 5.10 1.80 0.00
86.00 5.10 1.80 0.00 190.00 5.10 1.80 0.00
88.00 5.10 1.80 0.00 192.00 5.10 1.80 0.00
90.00 5.10 1.80 0.00 194.00 5.10 1.80 0.00
92.00 5.10 1.80 0.00 196.00 5.10 1.80 0.00
94.00 5.10 1.80 0.00 198.00 5.10 1.80 0.00
96.00 5.10 1.80 0.00 200.00 5.10 1.80 0.00
98.00 5.10 1.80 0.00
100.00 5.10 1.80 0.00
102.00 5.10 1.80 0.00

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 50.96 cfs @ 11.96 hrs, Volume= 2.342 af, Depth= 3.17"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
3.940 98 Paved parking & roofs
4.930 69 50-75% Grass cover, Fair, HSG B
8.870 82 Weighted Average
4.930 Pervious Area
3.940 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.17 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.17 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.17 0.00
6.00 0.41 0.00 0.00 110.00 5.10 3.17 0.00
8.00 0.61 0.01 0.13 112.00 5.10 3.17 0.00
10.00 0.92 0.09 0.57 114.00 5.10 3.17 0.00
12.00 3.38 1.69 43.28 116.00 5.10 3.17 0.00
14.00 4.18 2.36 1.52 118.00 5.10 3.17 0.00
16.00 4.49 2.63 0.94 120.00 5.10 3.17 0.00
18.00 4.70 2.81 0.73 122.00 5.10 3.17 0.00
20.00 4.86 2.95 0.54 124.00 5.10 3.17 0.00
22.00 4.98 3.06 0.49 126.00 5.10 3.17 0.00
24.00 5.10 3.17 0.45 128.00 5.10 3.17 0.00
26.00 5.10 3.17 0.00 130.00 5.10 3.17 0.00
28.00 5.10 3.17 0.00 132.00 5.10 3.17 0.00
30.00 5.10 3.17 0.00 134.00 5.10 3.17 0.00
32.00 5.10 3.17 0.00 136.00 5.10 3.17 0.00
34.00 5.10 3.17 0.00 138.00 5.10 3.17 0.00
36.00 5.10 3.17 0.00 140.00 5.10 3.17 0.00
38.00 5.10 3.17 0.00 142.00 5.10 3.17 0.00
40.00 5.10 3.17 0.00 144.00 5.10 3.17 0.00
42.00 5.10 3.17 0.00 146.00 5.10 3.17 0.00
44.00 5.10 3.17 0.00 148.00 5.10 3.17 0.00
46.00 5.10 3.17 0.00 150.00 5.10 3.17 0.00
48.00 5.10 3.17 0.00 152.00 5.10 3.17 0.00
50.00 5.10 3.17 0.00 154.00 5.10 3.17 0.00
52.00 5.10 3.17 0.00 156.00 5.10 3.17 0.00
54.00 5.10 3.17 0.00 158.00 5.10 3.17 0.00
56.00 5.10 3.17 0.00 160.00 5.10 3.17 0.00
58.00 5.10 3.17 0.00 162.00 5.10 3.17 0.00
60.00 5.10 3.17 0.00 164.00 5.10 3.17 0.00
62.00 5.10 3.17 0.00 166.00 5.10 3.17 0.00
64.00 5.10 3.17 0.00 168.00 5.10 3.17 0.00
66.00 5.10 3.17 0.00 170.00 5.10 3.17 0.00
68.00 5.10 3.17 0.00 172.00 5.10 3.17 0.00
70.00 5.10 3.17 0.00 174.00 5.10 3.17 0.00
72.00 5.10 3.17 0.00 176.00 5.10 3.17 0.00
74.00 5.10 3.17 0.00 178.00 5.10 3.17 0.00
76.00 5.10 3.17 0.00 180.00 5.10 3.17 0.00
78.00 5.10 3.17 0.00 182.00 5.10 3.17 0.00
80.00 5.10 3.17 0.00 184.00 5.10 3.17 0.00
82.00 5.10 3.17 0.00 186.00 5.10 3.17 0.00
84.00 5.10 3.17 0.00 188.00 5.10 3.17 0.00
86.00 5.10 3.17 0.00 190.00 5.10 3.17 0.00
88.00 5.10 3.17 0.00 192.00 5.10 3.17 0.00
90.00 5.10 3.17 0.00 194.00 5.10 3.17 0.00
92.00 5.10 3.17 0.00 196.00 5.10 3.17 0.00
94.00 5.10 3.17 0.00 198.00 5.10 3.17 0.00
96.00 5.10 3.17 0.00 200.00 5.10 3.17 0.00
98.00 5.10 3.17 0.00
100.00 5.10 3.17 0.00
102.00 5.10 3.17 0.00

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP3)
Inflow Area = 8.870 ac, Inflow Depth = 3.17" for 10-yr Concord event
Inflow = 50.96 cfs @ 11.96 hrs, Volume= 2.342 af
Outflow = 7.65 cfs @ 12.15 hrs, Volume= 2.342 af, Atten= 85%, Lag= 11.5 min
Primary = 7.65 cfs @ 12.15 hrs, Volume= 2.342 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 632.32' @ 12.15 hrs Surf.Area= 14,838 sf Storage= 51,994 cf
Plug-Flow detention time= 654.5 min calculated for 2.342 af(100% of inflow)
Center-of-Mass det. time= 654.5 min ( 1,466.0 - 811.5 )
Volume Invert Avail.Storage Storage Description
#1 628.00' 78,899 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
628.00 9,379 0 0
630.00 11,768 21,147 21,147
632.00 14,381 26,149 47,296
634.00 17,222 31,603 78,899
Device Routing Invert Outlet Devices
#1 Primary 614.18' 18.0" x 30.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 614.00' S= 0.0060 '/' Cc= 0.900 n= 0.013
#2 Device 1 628.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.140 0.196 0.251 0.307 0.363 0.419
#3 Device 1 630.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 632.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 633.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=7.65 cfs @ 12.15 hrs HW=632.32' (Free Discharge)
t-1=Culvert (Passes 7.65 cfs of 35.48 cfs potential flow)
2=Exfiltration (Custom Controls 0.33 cfs)
3=Orifice/Grate (Orifice Controls 1.36 cfs @ 6.93 fps)
4=Top of Riser (Weir Controls 5.96 cfs @ 1.85 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=628.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP3)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 628.00 0.00 0.00 0.00
5.00 0.00 0 628.00 0.00 0.00 0.00
10.00 0.57 2,516 628.26 0.04 0.04 0.00
15.00 1.21 46,846 631.97 1.54 1.54 0.00
20.00 0.54 36,308 631.21 1.19 1.19 0.00
25.00 0.00 26,443 630.44 0.63 0.63 0.00
30.00 0.00 20,852 629.97 0.19 0.19 0.00
35.00 0.00 17,497 629.68 0.18 0.18 0.00
40.00 0.00 14,426 629.41 0.16 0.16 0.00
45.00 0.00 11,623 629.15 0.15 0.15 0.00
50.00 0.00 9,093 628.92 0.13 0.13 0.00
55.00 0.00 7,043 628.72 0.10 0.10 0.00
60.00 0.00 5,440 628.56 0.08 0.08 0.00
65.00 0.00 4,193 628.43 0.06 0.06 0.00
70.00 0.00 3,226 628.34 0.05 0.05 0.00
75.00 0.00 2,478 628.26 0.04 0.04 0.00
80.00 0.00 1,902 628.20 0.03 0.03 0.00
85.00 0.00 1,458 628.15 0.02 0.02 0.00
90.00 0.00 1,117 628.12 0.02 0.02 0.00
95.00 0.00 855 628.09 0.01 0.01 0.00
100.00 0.00 655 628.07 0.01 0.01 0.00
105.00 0.00 501 628.05 0.01 0.01 0.00
110.00 0.00 383 628.04 0.01 0.01 0.00
115.00 0.00 293 628.03 0.00 0.00 0.00
120.00 0.00 225 628.02 0.00 0.00 0.00
125.00 0.00 172 628.02 0.00 0.00 0.00
130.00 0.00 131 628.01 0.00 0.00 0.00
135.00 0.00 101 628.01 0.00 0.00 0.00
140.00 0.00 77 628.01 0.00 0.00 0.00
145.00 0.00 59 628.01 0.00 0.00 0.00
150.00 0.00 45 628.00 0.00 0.00 0.00
155.00 0.00 34 628.00 0.00 0.00 0.00
160.00 0.00 26 628.00 0.00 0.00 0.00
165.00 0.00 20 628.00 0.00 0.00 0.00
170.00 0.00 15 628.00 0.00 0.00 0.00
175.00 0.00 12 628.00 0.00 0.00 0.00
180.00 0.00 9 628.00 0.00 0.00 0.00
185.00 0.00 7 628.00 0.00 0.00 0.00
190.00 0.00 5 628.00 0.00 0.00 0.00
195.00 0.00 4 628.00 0.00 0.00 0.00
200.00 0.00 3 628.00 0.00 0.00 0.00

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP3)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
628.00 0.00 0.00 0.00 633.20 36.04 33.65 2.40
628.10 0.01 0.01 0.00 633.30 39.39 34.97 4.42
628.20 0.03 0.03 0.00 633.40 43.08 36.25 6.83
628.30 0.04 0.04 0.00 633.50 46.21 36.67 9.55
628.40 0.06 0.06 0.00 633.60 49.31 36.77 12.55
628.50 0.07 0.07 0.00 633.70 52.50 36.86 15.64
628.60 0.08 0.08 0.00 633.80 55.85 36.96 18.89
628.70 0.10 0.10 0.00 633.90 59.56 37.06 22.50
628.80 0.11 0.11 0.00 634.00 63.46 37.16 26.30
628.90 0.13 0.13 0.00
629.00 0.14 0.14 0.00
629.10 0.15 0.15 0.00
629.20 0.15 0.15 0.00
629.30 0.16 0.16 0.00
629.40 0.16 0.16 0.00
629.50 0.17 0.17 0.00
629.60 0.17 0.17 0.00
629.70 0.18 0.18 0.00
629.80 0.18 0.18 0.00
629.90 0.19 0.19 0.00
630.00 0.20 0.20 0.00
630.10 0.23 0.23 0.00
630.20 0.32 0.32 0.00
630.30 0.44 0.44 0.00
630.40 0.58 0.58 0.00
630.50 0.70 0.70 0.00
630.60 0.79 0.79 0.00
630.70 0.87 0.87 0.00
630.80 0.94 0.94 0.00
630.90 1.01 1.01 0.00
631.00 1.07 1.07 0.00
631.10 1.13 1.13 0.00
631.20 1.18 1.18 0.00
631.30 1.24 1.24 0.00
631.40 1.29 1.29 0.00
631.50 1.34 1.34 0.00
631.60 1.38 1.38 0.00
631.70 1.43 1.43 0.00
631.80 1.47 1.47 0.00
631.90 1.52 1.52 0.00
632.00 1.56 1.56 0.00
632.10 2.63 2.63 0.00
632.20 4.56 4.56 0.00
632.30 7.05 7.05 0.00
632.40 9.99 9.99 0.00
632.50 13.31 13.31 0.00
632.60 16.99 16.99 0.00
632.70 20.98 20.98 0.00
632.80 25.26 25.26 0.00
632.90 29.30 29.30 0.00
633.00 30.82 30.82 0.00
633.10 33.11 32.26 0.85

2020.17-BMP3 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP3)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
628.00 9,379 0 633.20 16,086 65,576
628.10 9,498 944 633.30 16,228 67,192
628.20 9,618 1,900 633.40 16,370 68,821
628.30 9,737 2,867 633.50 16,512 70,466
628.40 9,857 3,847 633.60 16,654 72,124
628.50 9,976 4,839 633.70 16,796 73,796
628.60 10,096 5,842 633.80 16,938 75,483
628.70 10,215 6,858 633.90 17,080 77,184
628.80 10,335 7,885 634.00 17,222 78,899
628.90 10,454 8,925
629.00 10,574 9,976
629.10 10,693 11,040
629.20 10,812 12,115
629.30 10,932 13,202
629.40 11,051 14,301
629.50 11,171 15,412
629.60 11,290 16,535
629.70 11,410 17,670
629.80 11,529 18,817
629.90 11,649 19,976
630.00 11,768 21,147
630.10 11,899 22,330
630.20 12,029 23,527
630.30 12,160 24,736
630.40 12,291 25,959
630.50 12,421 27,194
630.60 12,552 28,443
630.70 12,683 29,705
630.80 12,813 30,979
630.90 12,944 32,267
631.00 13,075 33,568
631.10 13,205 34,882
631.20 13,336 36,209
631.30 13,466 37,549
631.40 13,597 38,903
631.50 13,728 40,269
631.60 13,858 41,648
631.70 13,989 43,040
631.80 14,120 44,446
631.90 14,250 45,864
632.00 14,381 47,296
632.10 14,523 48,741
632.20 14,665 50,201
632.30 14,807 51,674
632.40 14,949 53,162
632.50 15,091 54,664
632.60 15,233 56,180
632.70 15,375 57,711
632.80 15,517 59,255
632.90 15,659 60,814
633.00 15,802 62,387
633.10 15,944 63,975

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.870 ac Runoff Depth=2.44"
Flow Length=568' Tc=17.1 min CN=66 Runoff=25.90 cfs 1.804 af
Subcatchment 2S: (Post Developed) Runoff Area=8.870 ac Runoff Depth=3.99"
Tc=5.0 min CN=82 Runoff=63.37 cfs 2.947 af
Pond 3P: (BMP3) Peak Elev=632.83' Storage=59,655 cf Inflow=63.37 cfs 2.947 af
Primary=26.42 cfs 2.947 af Secondary=0.00 cfs 0.000 af Outflow=26.42 cfs 2.947 af
Total Runoff Area = 17.740 ac Runoff Volume =4.751 of Average Runoff Depth = 3.21"
77.79% Pervious Area= 13.800 ac 22.21% Impervious Area = 3.940 ac

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 25.90 cfs @ 12.10 hrs, Volume= 1.804 af, Depth= 2.44"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description _
4.340 60 Woods, Fair, HSG B
0.900 73 Woods, Fair, HSG C
1.090 79 Pasture/grassland/range, Fair, HSG C
2.540 69 Pasture/grassland/range, Fair, HSG B _
8.870 66 Weighted Average
8.870 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.8 100 0.0288 0.14 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
5.3 468 0.0880 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
17.1 568 Total

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 2.44 0.00
2.00 0.13 0.00 0.00 106.00 6.00 2.44 0.00
4.00 0.29 0.00 0.00 108.00 6.00 2.44 0.00
6.00 0.48 0.00 0.00 110.00 6.00 2.44 0.00
8.00 0.72 0.00 0.00 112.00 6.00 2.44 0.00
10.00 1.09 0.00 0.01 114.00 6.00 2.44 0.00
12.00 3.98 1.07 18.60 116.00 6.00 2.44 0.00
14.00 4.92 1.67 1.52 118.00 6.00 2.44 0.00
16.00 5.28 1.92 0.93 120.00 6.00 2.44 0.00
18.00 5.53 2.10 0.71 122.00 6.00 2.44 0.00
20.00 5.71 2.23 0.53 124.00 6.00 2.44 0.00
22.00 5.86 2.34 0.48 126.00 6.00 2.44 0.00
24.00 6.00 2.44 0.44 128.00 6.00 2.44 0.00
26.00 6.00 2.44 0.00 130.00 6.00 2.44 0.00
28.00 6.00 2.44 0.00 132.00 6.00 2.44 0.00
30.00 6.00 2.44 0.00 134.00 6.00 2.44 0.00
32.00 6.00 2.44 0.00 136.00 6.00 2.44 0.00
34.00 6.00 2.44 0.00 138.00 6.00 2.44 0.00
36.00 6.00 2.44 0.00 140.00 6.00 2.44 0.00
38.00 6.00 2.44 0.00 142.00 6.00 2.44 0.00
40.00 6.00 2.44 0.00 144.00 6.00 2.44 0.00
42.00 6.00 2.44 0.00 146.00 6.00 2.44 0.00
44.00 6.00 2.44 0.00 148.00 6.00 2.44 0.00
46.00 6.00 2.44 0.00 150.00 6.00 2.44 0.00
48.00 6.00 2.44 0.00 152.00 6.00 2.44 0.00
50.00 6.00 2.44 0.00 154.00 6.00 2.44 0.00
52.00 6.00 2.44 0.00 156.00 6.00 2.44 0.00
54.00 6.00 2.44 0.00 158.00 6.00 2.44 0.00
56.00 6.00 2.44 0.00 160.00 6.00 2.44 0.00
58.00 6.00 2.44 0.00 162.00 6.00 2.44 0.00
60.00 6.00 2.44 0.00 164.00 6.00 2.44 0.00
62.00 6.00 2.44 0.00 166.00 6.00 2.44 0.00
64.00 6.00 2.44 0.00 168.00 6.00 2.44 0.00
66.00 6.00 2.44 0.00 170.00 6.00 2.44 0.00
68.00 6.00 2.44 0.00 172.00 6.00 2.44 0.00
70.00 6.00 2.44 0.00 174.00 6.00 2.44 0.00
72.00 6.00 2.44 0.00 176.00 6.00 2.44 0.00
74.00 6.00 2.44 0.00 178.00 6.00 2.44 0.00
76.00 6.00 2.44 0.00 180.00 6.00 2.44 0.00
78.00 6.00 2.44 0.00 182.00 6.00 2.44 0.00
80.00 6.00 2.44 0.00 184.00 6.00 2.44 0.00
82.00 6.00 2.44 0.00 186.00 6.00 2.44 0.00
84.00 6.00 2.44 0.00 188.00 6.00 2.44 0.00
86.00 6.00 2.44 0.00 190.00 6.00 2.44 0.00
88.00 6.00 2.44 0.00 192.00 6.00 2.44 0.00
90.00 6.00 2.44 0.00 194.00 6.00 2.44 0.00
92.00 6.00 2.44 0.00 196.00 6.00 2.44 0.00
94.00 6.00 2.44 0.00 198.00 6.00 2.44 0.00
96.00 6.00 2.44 0.00 200.00 6.00 2.44 0.00
98.00 6.00 2.44 0.00
100.00 6.00 2.44 0.00
102.00 6.00 2.44 0.00

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 63.37 cfs @ 11.96 hrs, Volume= 2.947 af, Depth= 3.99"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
3.940 98 Paved parking & roofs
4.930 69 50-75% Grass cover, Fair, HSG B
8.870 82 Weighted Average
4.930 Pervious Area
3.940 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 3.99 0.00
2.00 0.13 0.00 0.00 106.00 6.00 3.99 0.00
4.00 0.29 0.00 0.00 108.00 6.00 3.99 0.00
6.00 0.48 0.00 0.03 110.00 6.00 3.99 0.00
8.00 0.72 0.03 0.24 112.00 6.00 3.99 0.00
10.00 1.09 0.15 0.82 114.00 6.00 3.99 0.00
12.00 3.98 2.18 53.55 116.00 6.00 3.99 0.00
14.00 4.92 3.01 1.84 118.00 6.00 3.99 0.00
16.00 5.28 3.33 1.14 120.00 6.00 3.99 0.00
18.00 5.53 3.55 0.89 122.00 6.00 3.99 0.00
20.00 5.71 3.72 0.65 124.00 6.00 3.99 0.00
22.00 5.86 3.86 0.59 126.00 6.00 3.99 0.00
24.00 6.00 3.99 0.54 128.00 6.00 3.99 0.00
26.00 6.00 3.99 0.00 130.00 6.00 3.99 0.00
28.00 6.00 3.99 0.00 132.00 6.00 3.99 0.00
30.00 6.00 3.99 0.00 134.00 6.00 3.99 0.00
32.00 6.00 3.99 0.00 136.00 6.00 3.99 0.00
34.00 6.00 3.99 0.00 138.00 6.00 3.99 0.00
36.00 6.00 3.99 0.00 140.00 6.00 3.99 0.00
38.00 6.00 3.99 0.00 142.00 6.00 3.99 0.00
40.00 6.00 3.99 0.00 144.00 6.00 3.99 0.00
42.00 6.00 3.99 0.00 146.00 6.00 3.99 0.00
44.00 6.00 3.99 0.00 148.00 6.00 3.99 0.00
46.00 6.00 3.99 0.00 150.00 6.00 3.99 0.00
48.00 6.00 3.99 0.00 152.00 6.00 3.99 0.00
50.00 6.00 3.99 0.00 154.00 6.00 3.99 0.00
52.00 6.00 3.99 0.00 156.00 6.00 3.99 0.00
54.00 6.00 3.99 0.00 158.00 6.00 3.99 0.00
56.00 6.00 3.99 0.00 160.00 6.00 3.99 0.00
58.00 6.00 3.99 0.00 162.00 6.00 3.99 0.00
60.00 6.00 3.99 0.00 164.00 6.00 3.99 0.00
62.00 6.00 3.99 0.00 166.00 6.00 3.99 0.00
64.00 6.00 3.99 0.00 168.00 6.00 3.99 0.00
66.00 6.00 3.99 0.00 170.00 6.00 3.99 0.00
68.00 6.00 3.99 0.00 172.00 6.00 3.99 0.00
70.00 6.00 3.99 0.00 174.00 6.00 3.99 0.00
72.00 6.00 3.99 0.00 176.00 6.00 3.99 0.00
74.00 6.00 3.99 0.00 178.00 6.00 3.99 0.00
76.00 6.00 3.99 0.00 180.00 6.00 3.99 0.00
78.00 6.00 3.99 0.00 182.00 6.00 3.99 0.00
80.00 6.00 3.99 0.00 184.00 6.00 3.99 0.00
82.00 6.00 3.99 0.00 186.00 6.00 3.99 0.00
84.00 6.00 3.99 0.00 188.00 6.00 3.99 0.00
86.00 6.00 3.99 0.00 190.00 6.00 3.99 0.00
88.00 6.00 3.99 0.00 192.00 6.00 3.99 0.00
90.00 6.00 3.99 0.00 194.00 6.00 3.99 0.00
92.00 6.00 3.99 0.00 196.00 6.00 3.99 0.00
94.00 6.00 3.99 0.00 198.00 6.00 3.99 0.00
96.00 6.00 3.99 0.00 200.00 6.00 3.99 0.00
98.00 6.00 3.99 0.00
100.00 6.00 3.99 0.00
102.00 6.00 3.99 0.00

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP3)
Inflow Area = 8.870 ac, Inflow Depth = 3.99" for 25-yr Concord event
Inflow = 63.37 cfs @ 11.96 hrs, Volume= 2.947 af
Outflow = 26.42 cfs @ 12.05 hrs, Volume= 2.947 af, Atten= 58%, Lag= 5.7 min
Primary = 26.42 cfs @ 12.05 hrs, Volume= 2.947 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 632.83' @ 12.05 hrs Surf.Area= 15,554 sf Storage= 59,655 cf
Plug-Flow detention time= 545.6 min calculated for 2.947 af(100% of inflow)
Center-of-Mass det. time= 545.6 min ( 1,350.5 - 804.9 )
Volume Invert Avail.Storage Storage Description
#1 628.00' 78,899 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
628.00 9,379 0 0
630.00 11,768 21,147 21,147
632.00 14,381 26,149 47,296
634.00 17,222 31,603 78,899
Device Routing Invert Outlet Devices
#1 Primary 614.18' 18.0" x 30.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 614.00' S= 0.0060 'I' Cc= 0.900 n= 0.013
#2 Device 1 628.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.140 0.196 0.251 0.307 0.363 0.419
#3 Device 1 630.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 632.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 633.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=26.35 cfs @ 12.05 hrs HW=632.82' (Free Discharge)
t-1=Culvert (Passes 26.35 cfs of 35.99 cfs potential flow)
2=Exfiltration (Custom Controls 0.35 cfs)
3=Orifice/Grate (Orifice Controls 1.52 cfs @ 7.73 fps)
4=Top of Riser (Weir Controls 24.48 cfs @ 2.97 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=628.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP3)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 628.00 0.00 0.00 0.00
5.00 0.00 0 628.00 0.00 0.00 0.00
10.00 0.82 4,231 628.44 0.06 0.06 0.00
15.00 1.47 47,505 632.01 1.63 1.63 0.00
20.00 0.65 38,837 631.40 1.28 1.28 0.00
25.00 0.00 28,279 630.59 0.78 0.78 0.00
30.00 0.00 21,363 630.02 0.20 0.20 0.00
35.00 0.00 17,964 629.73 0.18 0.18 0.00
40.00 0.00 14,853 629.45 0.17 0.17 0.00
45.00 0.00 12,012 629.19 0.15 0.15 0.00
50.00 0.00 9,432 628.95 0.13 0.13 0.00
55.00 0.00 7,309 628.74 0.10 0.10 0.00
60.00 0.00 5,648 628.58 0.08 0.08 0.00
65.00 0.00 4,354 628.45 0.06 0.06 0.00
70.00 0.00 3,351 628.35 0.05 0.05 0.00
75.00 0.00 2,574 628.27 0.04 0.04 0.00
80.00 0.00 1,976 628.21 0.03 0.03 0.00
85.00 0.00 1,515 628.16 0.02 0.02 0.00
90.00 0.00 1,161 628.12 0.02 0.02 0.00
95.00 0.00 889 628.09 0.01 0.01 0.00
100.00 0.00 681 628.07 0.01 0.01 0.00
105.00 0.00 521 628.06 0.01 0.01 0.00
110.00 0.00 399 628.04 0.01 0.01 0.00
115.00 0.00 305 628.03 0.00 0.00 0.00
120.00 0.00 233 628.02 0.00 0.00 0.00
125.00 0.00 179 628.02 0.00 0.00 0.00
130.00 0.00 137 628.01 0.00 0.00 0.00
135.00 0.00 105 628.01 0.00 0.00 0.00
140.00 0.00 80 628.01 0.00 0.00 0.00
145.00 0.00 61 628.01 0.00 0.00 0.00
150.00 0.00 47 628.00 0.00 0.00 0.00
155.00 0.00 36 628.00 0.00 0.00 0.00
160.00 0.00 27 628.00 0.00 0.00 0.00
165.00 0.00 21 628.00 0.00 0.00 0.00
170.00 0.00 16 628.00 0.00 0.00 0.00
175.00 0.00 12 628.00 0.00 0.00 0.00
180.00 0.00 9 628.00 0.00 0.00 0.00
185.00 0.00 7 628.00 0.00 0.00 0.00
190.00 0.00 6 628.00 0.00 0.00 0.00
195.00 0.00 4 628.00 0.00 0.00 0.00
200.00 0.00 3 628.00 0.00 0.00 0.00

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP3)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
628.00 0.00 0.00 0.00 633.20 36.04 33.65 2.40
628.10 0.01 0.01 0.00 633.30 39.39 34.97 4.42
628.20 0.03 0.03 0.00 633.40 43.08 36.25 6.83
628.30 0.04 0.04 0.00 633.50 46.21 36.67 9.55
628.40 0.06 0.06 0.00 633.60 49.31 36.77 12.55
628.50 0.07 0.07 0.00 633.70 52.50 36.86 15.64
628.60 0.08 0.08 0.00 633.80 55.85 36.96 18.89
628.70 0.10 0.10 0.00 633.90 59.56 37.06 22.50
628.80 0.11 0.11 0.00 634.00 63.46 37.16 26.30
628.90 0.13 0.13 0.00
629.00 0.14 0.14 0.00
629.10 0.15 0.15 0.00
629.20 0.15 0.15 0.00
629.30 0.16 0.16 0.00
629.40 0.16 0.16 0.00
629.50 0.17 0.17 0.00
629.60 0.17 0.17 0.00
629.70 0.18 0.18 0.00
629.80 0.18 0.18 0.00
629.90 0.19 0.19 0.00
630.00 0.20 0.20 0.00
630.10 0.23 0.23 0.00
630.20 0.32 0.32 0.00
630.30 0.44 0.44 0.00
630.40 0.58 0.58 0.00
630.50 0.70 0.70 0.00
630.60 0.79 0.79 0.00
630.70 0.87 0.87 0.00
630.80 0.94 0.94 0.00
630.90 1.01 1.01 0.00
631.00 1.07 1.07 0.00
631.10 1.13 1.13 0.00
631.20 1.18 1.18 0.00
631.30 1.24 1.24 0.00
631.40 1.29 1.29 0.00
631.50 1.34 1.34 0.00
631.60 1.38 1.38 0.00
631.70 1.43 1.43 0.00
631.80 1.47 1.47 0.00
631.90 1.52 1.52 0.00
632.00 1.56 1.56 0.00
632.10 2.63 2.63 0.00
632.20 4.56 4.56 0.00
632.30 7.05 7.05 0.00
632.40 9.99 9.99 0.00
632.50 13.31 13.31 0.00
632.60 16.99 16.99 0.00
632.70 20.98 20.98 0.00
632.80 25.26 25.26 0.00
632.90 29.30 29.30 0.00
633.00 30.82 30.82 0.00
633.10 33.11 32.26 0.85

2020.17-BMP3 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP3)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
628.00 9,379 0 633.20 16,086 65,576
628.10 9,498 944 633.30 16,228 67,192
628.20 9,618 1,900 633.40 16,370 68,821
628.30 9,737 2,867 633.50 16,512 70,466
628.40 9,857 3,847 633.60 16,654 72,124
628.50 9,976 4,839 633.70 16,796 73,796
628.60 10,096 5,842 633.80 16,938 75,483
628.70 10,215 6,858 633.90 17,080 77,184
628.80 10,335 7,885 634.00 17,222 78,899
628.90 10,454 8,925
629.00 10,574 9,976
629.10 10,693 11,040
629.20 10,812 12,115
629.30 10,932 13,202
629.40 11,051 14,301
629.50 11,171 15,412
629.60 11,290 16,535
629.70 11,410 17,670
629.80 11,529 18,817
629.90 11,649 19,976
630.00 11,768 21,147
630.10 11,899 22,330
630.20 12,029 23,527
630.30 12,160 24,736
630.40 12,291 25,959
630.50 12,421 27,194
630.60 12,552 28,443
630.70 12,683 29,705
630.80 12,813 30,979
630.90 12,944 32,267
631.00 13,075 33,568
631.10 13,205 34,882
631.20 13,336 36,209
631.30 13,466 37,549
631.40 13,597 38,903
631.50 13,728 40,269
631.60 13,858 41,648
631.70 13,989 43,040
631.80 14,120 44,446
631.90 14,250 45,864
632.00 14,381 47,296
632.10 14,523 48,741
632.20 14,665 50,201
632.30 14,807 51,674
632.40 14,949 53,162
632.50 15,091 54,664
632.60 15,233 56,180
632.70 15,375 57,711
632.80 15,517 59,255
632.90 15,659 60,814
633.00 15,802 62,387
633.10 15,944 63,975

2020.17-BMP3 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.870 ac Runoff Depth=3.05"
Flow Length=568' Tc=17.1 min CN=66 Runoff=32.62 cfs 2.253 af
Subcatchment 2S: (Post Developed) Runoff Area=8.870 ac Runoff Depth=4.73"
Tc=5.0 min CN=82 Runoff=74.44 cfs 3.496 af
Pond 3P: (BMP3) Peak Elev=633.25' Storage=66,446 cf Inflow=74.44 cfs 3.496 af
Primary=34.36 cfs 3.473 af Secondary=3.46 cfs 0.022 af Outflow=37.82 cfs 3.495 af
Total Runoff Area = 17.740 ac Runoff Volume = 5.749 af Average Runoff Depth = 3.89"
77.79% Pervious Area = 13.800 ac 22.21% Impervious Area = 3.940 ac

2020.17-BMP3 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 32.62 cfs @ 12.10 hrs, Volume= 2.253 af, Depth= 3.05"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
4.340 60 Woods, Fair, HSG B
0.900 73 Woods, Fair, HSG C
1.090 79 Pasture/grassland/range, Fair, HSG C
2.540 69 Pasture/grassland/range, Fair, HSG B
8.870 66 Weighted Average
8.870 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
11.8 100 0.0288 0.14 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
5.3 468 0.0880 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
17.1 568 Total

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 3.05 0.00
2.00 0.15 0.00 0.00 106.00 6.80 3.05 0.00
4.00 0.33 0.00 0.00 108.00 6.80 3.05 0.00
6.00 0.54 0.00 0.00 110.00 6.80 3.05 0.00
8.00 0.82 0.00 0.00 112.00 6.80 3.05 0.00
10.00 1.23 0.01 0.11 114.00 6.80 3.05 0.00
12.00 4.51 1.40 23.90 116.00 6.80 3.05 0.00
14.00 5.58 2.13 1.84 118.00 6.80 3.05 0.00
16.00 5.98 2.43 1.11 120.00 6.80 3.05 0.00
18.00 6.26 2.64 0.85 122.00 6.80 3.05 0.00
20.00 6.47 2.80 0.63 124.00 6.80 3.05 0.00
22.00 6.64 2.93 0.57 126.00 6.80 3.05 0.00
24.00 6.80 3.05 0.53 128.00 6.80 3.05 0.00
26.00 6.80 3.05 0.00 130.00 6.80 3.05 0.00
28.00 6.80 3.05 0.00 132.00 6.80 3.05 0.00
30.00 6.80 3.05 0.00 134.00 6.80 3.05 0.00
32.00 6.80 3.05 0.00 136.00 6.80 3.05 0.00
34.00 6.80 3.05 0.00 138.00 6.80 3.05 0.00
36.00 6.80 3.05 0.00 140.00 6.80 3.05 0.00
38.00 6.80 3.05 0.00 142.00 6.80 3.05 0.00
40.00 6.80 3.05 0.00 144.00 6.80 3.05 0.00
42.00 6.80 3.05 0.00 146.00 6.80 3.05 0.00
44.00 6.80 3.05 0.00 148.00 6.80 3.05 0.00
46.00 6.80 3.05 0.00 150.00 6.80 3.05 0.00
48.00 6.80 3.05 0.00 152.00 6.80 3.05 0.00
50.00 6.80 3.05 0.00 154.00 6.80 3.05 0.00
52.00 6.80 3.05 0.00 156.00 6.80 3.05 0.00
54.00 6.80 3.05 0.00 158.00 6.80 3.05 0.00
56.00 6.80 3.05 0.00 160.00 6.80 3.05 0.00
58.00 6.80 3.05 0.00 162.00 6.80 3.05 0.00
60.00 6.80 3.05 0.00 164.00 6.80 3.05 0.00
62.00 6.80 3.05 0.00 166.00 6.80 3.05 0.00
64.00 6.80 3.05 0.00 168.00 6.80 3.05 0.00
66.00 6.80 3.05 0.00 170.00 6.80 3.05 0.00
68.00 6.80 3.05 0.00 172.00 6.80 3.05 0.00
70.00 6.80 3.05 0.00 174.00 6.80 3.05 0.00
72.00 6.80 3.05 0.00 176.00 6.80 3.05 0.00
74.00 6.80 3.05 0.00 178.00 6.80 3.05 0.00
76.00 6.80 3.05 0.00 180.00 6.80 3.05 0.00
78.00 6.80 3.05 0.00 182.00 6.80 3.05 0.00
80.00 6.80 3.05 0.00 184.00 6.80 3.05 0.00
82.00 6.80 3.05 0.00 186.00 6.80 3.05 0.00
84.00 6.80 3.05 0.00 188.00 6.80 3.05 0.00
86.00 6.80 3.05 0.00 190.00 6.80 3.05 0.00
88.00 6.80 3.05 0.00 192.00 6.80 3.05 0.00
90.00 6.80 3.05 0.00 194.00 6.80 3.05 0.00
92.00 6.80 3.05 0.00 196.00 6.80 3.05 0.00
94.00 6.80 3.05 0.00 198.00 6.80 3.05 0.00
96.00 6.80 3.05 0.00 200.00 6.80 3.05 0.00
98.00 6.80 3.05 0.00
100.00 6.80 3.05 0.00
102.00 6.80 3.05 0.00

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 74.44 cfs @ 11.96 hrs, Volume= 3.496 af, Depth= 4.73"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
3.940 98 Paved parking & roofs
4.930 69 50-75% Grass cover, Fair, HSG B
8.870 82 Weighted Average
4.930 Pervious Area
3.940 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 4.73 0.00
2.00 0.15 0.00 0.00 106.00 6.80 4.73 0.00
4.00 0.33 0.00 0.00 108.00 6.80 4.73 0.00
6.00 0.54 0.00 0.09 110.00 6.80 4.73 0.00
8.00 0.82 0.06 0.35 112.00 6.80 4.73 0.00
10.00 1.23 0.21 1.07 114.00 6.80 4.73 0.00
12.00 4.51 2.64 62.68 116.00 6.80 4.73 0.00
14.00 5.58 3.60 2.13 118.00 6.80 4.73 0.00
16.00 5.98 3.97 1.32 120.00 6.80 4.73 0.00
18.00 6.26 4.23 1.02 122.00 6.80 4.73 0.00
20.00 6.47 4.42 0.75 124.00 6.80 4.73 0.00
22.00 6.64 4.58 0.68 126.00 6.80 4.73 0.00
24.00 6.80 4.73 0.63 128.00 6.80 4.73 0.00
26.00 6.80 4.73 0.00 130.00 6.80 4.73 0.00
28.00 6.80 4.73 0.00 132.00 6.80 4.73 0.00
30.00 6.80 4.73 0.00 134.00 6.80 4.73 0.00
32.00 6.80 4.73 0.00 136.00 6.80 4.73 0.00
34.00 6.80 4.73 0.00 138.00 6.80 4.73 0.00
36.00 6.80 4.73 0.00 140.00 6.80 4.73 0.00
38.00 6.80 4.73 0.00 142.00 6.80 4.73 0.00
40.00 6.80 4.73 0.00 144.00 6.80 4.73 0.00
42.00 6.80 4.73 0.00 146.00 6.80 4.73 0.00
44.00 6.80 4.73 0.00 148.00 6.80 4.73 0.00
46.00 6.80 4.73 0.00 150.00 6.80 4.73 0.00
48.00 6.80 4.73 0.00 152.00 6.80 4.73 0.00
50.00 6.80 4.73 0.00 154.00 6.80 4.73 0.00
52.00 6.80 4.73 0.00 156.00 6.80 4.73 0.00
54.00 6.80 4.73 0.00 158.00 6.80 4.73 0.00
56.00 6.80 4.73 0.00 160.00 6.80 4.73 0.00
58.00 6.80 4.73 0.00 162.00 6.80 4.73 0.00
60.00 6.80 4.73 0.00 164.00 6.80 4.73 0.00
62.00 6.80 4.73 0.00 166.00 6.80 4.73 0.00
64.00 6.80 4.73 0.00 168.00 6.80 4.73 0.00
66.00 6.80 4.73 0.00 170.00 6.80 4.73 0.00
68.00 6.80 4.73 0.00 172.00 6.80 4.73 0.00
70.00 6.80 4.73 0.00 174.00 6.80 4.73 0.00
72.00 6.80 4.73 0.00 176.00 6.80 4.73 0.00
74.00 6.80 4.73 0.00 178.00 6.80 4.73 0.00
76.00 6.80 4.73 0.00 180.00 6.80 4.73 0.00
78.00 6.80 4.73 0.00 182.00 6.80 4.73 0.00
80.00 6.80 4.73 0.00 184.00 6.80 4.73 0.00
82.00 6.80 4.73 0.00 186.00 6.80 4.73 0.00
84.00 6.80 4.73 0.00 188.00 6.80 4.73 0.00
86.00 6.80 4.73 0.00 190.00 6.80 4.73 0.00
88.00 6.80 4.73 0.00 192.00 6.80 4.73 0.00
90.00 6.80 4.73 0.00 194.00 6.80 4.73 0.00
92.00 6.80 4.73 0.00 196.00 6.80 4.73 0.00
94.00 6.80 4.73 0.00 198.00 6.80 4.73 0.00
96.00 6.80 4.73 0.00 200.00 6.80 4.73 0.00
98.00 6.80 4.73 0.00
100.00 6.80 4.73 0.00
102.00 6.80 4.73 0.00

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP3)
Inflow Area = 8.870 ac, Inflow Depth = 4.73" for 50-yr Concord event
Inflow = 74.44 cfs @ 11.96 hrs, Volume= 3.496 af
Outflow = 37.82 cfs @ 12.04 hrs, Volume= 3.495 af, Atten= 49%, Lag= 5.0 min
Primary = 34.36 cfs @ 12.04 hrs, Volume= 3.473 af
Secondary= 3.46 cfs @ 12.04 hrs, Volume= 0.022 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 633.25' @ 12.04 hrs Surf.Area= 16,162 sf Storage= 66,446 cf
Plug-Flow detention time= 477.2 min calculated for 3.495 af(100% of inflow)
Center-of-Mass det. time= 477.7 min ( 1,277.7 - 800.1 )
Volume Invert Avail.Storage Storage Description _
#1 628.00' 78,899 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
628.00 9,379 0 0
630.00 11,768 21,147 21,147
632.00 14,381 26,149 47,296
634.00 17,222 31,603 78,899
Device Routing Invert Outlet Devices
#1 Primary 614.18' 18.0" x 30.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 614.00' S= 0.0060 'I' Cc= 0.900 n= 0.013
#2 Device 1 628.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.140 0.196 0.251 0.307 0.363 0.419
#3 Device 1 630.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 632.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 633.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=34.36 cfs @ 12.04 hrs HW=633.25' (Free Discharge)
t-1=Culvert (Passes 34.36 cfs of 36.42 cfs potential flow)
2=Exfiltration (Custom Controls 0.38 cfs)
3=Orifice/Grate (Orifice Controls 1.64 cfs @ 8.34 fps)
4=Top of Riser (Orifice Controls 32.34 cfs @ 5.39 fps)
Secondary OutFlow Max=3.42 cfs @ 12.04 hrs HW=633.25' (Free Discharge)
t-5=Spillway (Weir Controls 3.42 cfs @ 1.35 fps)

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP3)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 628.00 0.00 0.00 0.00
5.00 0.00 0 628.00 0.00 0.00 0.00
10.00 1.07 6,016 628.62 0.09 0.09 0.00
15.00 1.70 47,827 632.04 1.85 1.85 0.00
20.00 0.75 40,782 631.54 1.35 1.35 0.00
25.00 0.00 29,942 630.72 0.88 0.88 0.00
30.00 0.00 21,770 630.05 0.21 0.21 0.00
35.00 0.00 18,328 629.76 0.18 0.18 0.00
40.00 0.00 15,186 629.48 0.17 0.17 0.00
45.00 0.00 12,315 629.22 0.15 0.15 0.00
50.00 0.00 9,702 628.97 0.14 0.14 0.00
55.00 0.00 7,521 628.76 0.11 0.11 0.00
60.00 0.00 5,813 628.60 0.08 0.08 0.00
65.00 0.00 4,483 628.46 0.06 0.06 0.00
70.00 0.00 3,450 628.36 0.05 0.05 0.00
75.00 0.00 2,651 628.28 0.04 0.04 0.00
80.00 0.00 2,035 628.21 0.03 0.03 0.00
85.00 0.00 1,561 628.16 0.02 0.02 0.00
90.00 0.00 1,196 628.13 0.02 0.02 0.00
95.00 0.00 916 628.10 0.01 0.01 0.00
100.00 0.00 701 628.07 0.01 0.01 0.00
105.00 0.00 537 628.06 0.01 0.01 0.00
110.00 0.00 411 628.04 0.01 0.01 0.00
115.00 0.00 314 628.03 0.00 0.00 0.00
120.00 0.00 240 628.03 0.00 0.00 0.00
125.00 0.00 184 628.02 0.00 0.00 0.00
130.00 0.00 141 628.01 0.00 0.00 0.00
135.00 0.00 108 628.01 0.00 0.00 0.00
140.00 0.00 82 628.01 0.00 0.00 0.00
145.00 0.00 63 628.01 0.00 0.00 0.00
150.00 0.00 48 628.01 0.00 0.00 0.00
155.00 0.00 37 628.00 0.00 0.00 0.00
160.00 0.00 28 628.00 0.00 0.00 0.00
165.00 0.00 22 628.00 0.00 0.00 0.00
170.00 0.00 17 628.00 0.00 0.00 0.00
175.00 0.00 13 628.00 0.00 0.00 0.00
180.00 0.00 10 628.00 0.00 0.00 0.00
185.00 0.00 7 628.00 0.00 0.00 0.00
190.00 0.00 6 628.00 0.00 0.00 0.00
195.00 0.00 4 628.00 0.00 0.00 0.00
200.00 0.00 3 628.00 0.00 0.00 0.00

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP3)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
628.00 0.00 0.00 0.00 633.20 36.04 33.65 2.40
628.10 0.01 0.01 0.00 633.30 39.39 34.97 4.42
628.20 0.03 0.03 0.00 633.40 43.08 36.25 6.83
628.30 0.04 0.04 0.00 633.50 46.21 36.67 9.55
628.40 0.06 0.06 0.00 633.60 49.31 36.77 12.55
628.50 0.07 0.07 0.00 633.70 52.50 36.86 15.64
628.60 0.08 0.08 0.00 633.80 55.85 36.96 18.89
628.70 0.10 0.10 0.00 633.90 59.56 37.06 22.50
628.80 0.11 0.11 0.00 634.00 63.46 37.16 26.30
628.90 0.13 0.13 0.00
629.00 0.14 0.14 0.00
629.10 0.15 0.15 0.00
629.20 0.15 0.15 0.00
629.30 0.16 0.16 0.00
629.40 0.16 0.16 0.00
629.50 0.17 0.17 0.00
629.60 0.17 0.17 0.00
629.70 0.18 0.18 0.00
629.80 0.18 0.18 0.00
629.90 0.19 0.19 0.00
630.00 0.20 0.20 0.00
630.10 0.23 0.23 0.00
630.20 0.32 0.32 0.00
630.30 0.44 0.44 0.00
630.40 0.58 0.58 0.00
630.50 0.70 0.70 0.00
630.60 0.79 0.79 0.00
630.70 0.87 0.87 0.00
630.80 0.94 0.94 0.00
630.90 1.01 1.01 0.00
631.00 1.07 1.07 0.00
631.10 1.13 1.13 0.00
631.20 1.18 1.18 0.00
631.30 1.24 1.24 0.00
631.40 1.29 1.29 0.00
631.50 1.34 1.34 0.00
631.60 1.38 1.38 0.00
631.70 1.43 1.43 0.00
631.80 1.47 1.47 0.00
631.90 1.52 1.52 0.00
632.00 1.56 1.56 0.00
632.10 2.63 2.63 0.00
632.20 4.56 4.56 0.00
632.30 7.05 7.05 0.00
632.40 9.99 9.99 0.00
632.50 13.31 13.31 0.00
632.60 16.99 16.99 0.00
632.70 20.98 20.98 0.00
632.80 25.26 25.26 0.00
632.90 29.30 29.30 0.00
633.00 30.82 30.82 0.00
633.10 33.11 32.26 0.85

2020.17-BMP3 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP3)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
628.00 9,379 0 633.20 16,086 65,576
628.10 9,498 944 633.30 16,228 67,192
628.20 9,618 1,900 633.40 16,370 68,821
628.30 9,737 2,867 633.50 16,512 70,466
628.40 9,857 3,847 633.60 16,654 72,124
628.50 9,976 4,839 633.70 16,796 73,796
628.60 10,096 5,842 633.80 16,938 75,483
628.70 10,215 6,858 633.90 17,080 77,184
628.80 10,335 7,885 634.00 17,222 78,899
628.90 10,454 8,925
629.00 10,574 9,976
629.10 10,693 11,040
629.20 10,812 12,115
629.30 10,932 13,202
629.40 11,051 14,301
629.50 11,171 15,412
629.60 11,290 16,535
629.70 11,410 17,670
629.80 11,529 18,817
629.90 11,649 19,976
630.00 11,768 21,147
630.10 11,899 22,330
630.20 12,029 23,527
630.30 12,160 24,736
630.40 12,291 25,959
630.50 12,421 27,194
630.60 12,552 28,443
630.70 12,683 29,705
630.80 12,813 30,979
630.90 12,944 32,267
631.00 13,075 33,568
631.10 13,205 34,882
631.20 13,336 36,209
631.30 13,466 37,549
631.40 13,597 38,903
631.50 13,728 40,269
631.60 13,858 41,648
631.70 13,989 43,040
631.80 14,120 44,446
631.90 14,250 45,864
632.00 14,381 47,296
632.10 14,523 48,741
632.20 14,665 50,201
632.30 14,807 51,674
632.40 14,949 53,162
632.50 15,091 54,664
632.60 15,233 56,180
632.70 15,375 57,711
632.80 15,517 59,255
632.90 15,659 60,814
633.00 15,802 62,387
633.10 15,944 63,975

SAND FILTER-4
l '�
( I
8sA H+ 1 'fi
LitI, p
1
f -H`'PVC/ RHRA.YS ow..) I L
IH' 0.5Hd a._ ry�s
\ 1 N 01 RM7AP BERAf �.
o
\\\\ \ SAND FILTER
�I \ AREA: rsa sr ( )
\ \I 10 EMERGENCY SPUNKY j
i

Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 4
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 9.56 ac
Impervious area to filter forebay= 4.33 ac.
Impervious percentage= 45.26%
Rv=0.05+0.9(la) = 0.45736972
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 15872 cf (used to size Af)
WQV= 0.3644 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
631 10175 0 0
632 11544 10859.5 10859.5
633 13003 12273.5 23133
634 14461 13732 36865
635 16033 15247 52112
636 17604 16818.5 68930.5
637 19671 18637.5 87568
638 21737 20704 108272
Calculate Depth for WQ Volume:
632 10859.5
632.39 15872
634 36865
Elevation of WQ Volume= 632.39
3. Discount WQv:
0.75 x WQv 11904.01 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 76.0
Cn Post= 88.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 11.47 32.86 42.38 51.00
Post. Dev. 30.15 62.88 76.24 88.05
Routed 1.08 6.56 23.26 29.12
Peak Stage 633.97 636.27 636.76 637.31
Disch.Time 110 hours 0.69' Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
1984 SA(ft2) DV"12
2 FS SA = FS" K"T
11904 DV(FT3) where: SA =required minimum surface area of infiltration system(fK)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(10)
K =hydraulic conductivity of soil(in/hr)
72 T(hours) T =maximum dewatering time(72 hours)
6.Sediment Sand Sizing
11904 Design Volume(ft3)
5952 Sediment Chamber(ft3)
5952 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 330.6669 cf/hour 0.092 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
113 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 1808 holes
50%of perforations= 904 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 7.5032 cfs which is 81.7 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
Dimensions of Riser
7.7 Height of Riser,ft. 2 ft L
6 Area of Riser,s.f. 3 ft W
46.2 Volume of Riser,c.f. 0.5 ft
2882.88 Weight of Water @ 62.4 pcf
3171.168 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
1.42 Volume of Concrete Req'd in c.y.
38.39 Volume of Concrete Req'd in c.f.
46.2 Volume of Concrete in Structure(cf)
-7.81 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
1 ft thick
2.0 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 1984 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 13226.68 0.153
2 18517.35 0.214
3 23808.02 0.276
4 29098.69 0.337
5 34389.36 0.398
6 39680.03 0.459
7 44970.7 0.520
8 50261.36 0.582
9 55552.04 0.643
10 60842.71 0.704

•
(Predeveloped)
e > 3P
(Post Developed) (BMP-4)
(Subcat Reach 'On. MI Drainage Diagram for 2020.17-BMP4
Prepared by{enter your company name here} 1/23/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP4
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
4.920 73 Woods, Fair, HSG C (1S)
5.230 79 50-75% Grass cover, Fair, HSG C (2S)
4.640 79 Pasture/grassland/range, Fair, HSG C (1S)
4.330 98 Paved parking & roofs (2S)
19.120

2020.17-BMP4 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.560 ac Runoff Depth=0.95"
Flow Length=512' Tc=14.6 min CN=76 Runoff=11.47 cfs 0.755 af
Subcatchment 2S: (Post Developed) Runoff Area=9.560 ac Runoff Depth=1.73"
Tc=5.0 min CN=88 Runoff=30.15 cfs 1.378 af
Pond 3P: (BMP-4) Peak Elev=633.97' Storage=36,448 cf Inflow=30.15 cfs 1.378 af
Primary=1.08 cfs 1.378 af Secondary=0.00 cfs 0.000 af Outflow=1.08 cfs 1.378 af
Total Runoff Area = 19.120 ac Runoff Volume = 2.133 af Average Runoff Depth = 1.34"
77.35% Pervious Area = 14.790 ac 22.65% Impervious Area = 4.330 ac

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 11.47 cfs @ 12.08 hrs, Volume= 0.755 af, Depth= 0.95"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.920 73 Woods, Fair, HSG C
4.640 79 Pasture/grassland/range, Fair, HSG C
9.560 76 Weighted Average
9.560 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 100 0.0439 0.17 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
4.6 412 0.0875 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.6 512 Total

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.95 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.95 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.95 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.95 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.95 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.95 0.00
12.00 1.92 0.37 8.95 116.00 2.90 0.95 0.00
14.00 2.38 0.62 0.67 118.00 2.90 0.95 0.00
16.00 2.55 0.73 0.42 120.00 2.90 0.95 0.00
18.00 2.67 0.80 0.33 122.00 2.90 0.95 0.00
20.00 2.76 0.86 0.24 124.00 2.90 0.95 0.00
22.00 2.83 0.90 0.22 126.00 2.90 0.95 0.00
24.00 2.90 0.95 0.21 128.00 2.90 0.95 0.00
26.00 2.90 0.95 0.00 130.00 2.90 0.95 0.00
28.00 2.90 0.95 0.00 132.00 2.90 0.95 0.00
30.00 2.90 0.95 0.00 134.00 2.90 0.95 0.00
32.00 2.90 0.95 0.00 136.00 2.90 0.95 0.00
34.00 2.90 0.95 0.00 138.00 2.90 0.95 0.00
36.00 2.90 0.95 0.00 140.00 2.90 0.95 0.00
38.00 2.90 0.95 0.00 142.00 2.90 0.95 0.00
40.00 2.90 0.95 0.00 144.00 2.90 0.95 0.00
42.00 2.90 0.95 0.00 146.00 2.90 0.95 0.00
44.00 2.90 0.95 0.00 148.00 2.90 0.95 0.00
46.00 2.90 0.95 0.00 150.00 2.90 0.95 0.00
48.00 2.90 0.95 0.00 152.00 2.90 0.95 0.00
50.00 2.90 0.95 0.00 154.00 2.90 0.95 0.00
52.00 2.90 0.95 0.00 156.00 2.90 0.95 0.00
54.00 2.90 0.95 0.00 158.00 2.90 0.95 0.00
56.00 2.90 0.95 0.00 160.00 2.90 0.95 0.00
58.00 2.90 0.95 0.00 162.00 2.90 0.95 0.00
60.00 2.90 0.95 0.00 164.00 2.90 0.95 0.00
62.00 2.90 0.95 0.00 166.00 2.90 0.95 0.00
64.00 2.90 0.95 0.00 168.00 2.90 0.95 0.00
66.00 2.90 0.95 0.00 170.00 2.90 0.95 0.00
68.00 2.90 0.95 0.00 172.00 2.90 0.95 0.00
70.00 2.90 0.95 0.00 174.00 2.90 0.95 0.00
72.00 2.90 0.95 0.00 176.00 2.90 0.95 0.00
74.00 2.90 0.95 0.00 178.00 2.90 0.95 0.00
76.00 2.90 0.95 0.00 180.00 2.90 0.95 0.00
78.00 2.90 0.95 0.00 182.00 2.90 0.95 0.00
80.00 2.90 0.95 0.00 184.00 2.90 0.95 0.00
82.00 2.90 0.95 0.00 186.00 2.90 0.95 0.00
84.00 2.90 0.95 0.00 188.00 2.90 0.95 0.00
86.00 2.90 0.95 0.00 190.00 2.90 0.95 0.00
88.00 2.90 0.95 0.00 192.00 2.90 0.95 0.00
90.00 2.90 0.95 0.00 194.00 2.90 0.95 0.00
92.00 2.90 0.95 0.00 196.00 2.90 0.95 0.00
94.00 2.90 0.95 0.00 198.00 2.90 0.95 0.00
96.00 2.90 0.95 0.00 200.00 2.90 0.95 0.00
98.00 2.90 0.95 0.00
100.00 2.90 0.95 0.00
102.00 2.90 0.95 0.00

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 30.15 cfs @ 11.96 hrs, Volume= 1.378 af, Depth= 1.73"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.330 98 Paved parking & roofs
5.230 79 50-75% Grass cover, Fair, HSG C
9.560 88 Weighted Average
5.230 Pervious Area
4.330 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.73 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.73 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.73 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.73 0.00
8.00 0.35 0.00 0.06 112.00 2.90 1.73 0.00
10.00 0.52 0.04 0.30 114.00 2.90 1.73 0.00
12.00 1.92 0.90 25.69 116.00 2.90 1.73 0.00
14.00 2.38 1.28 0.91 118.00 2.90 1.73 0.00
16.00 2.55 1.43 0.57 120.00 2.90 1.73 0.00
18.00 2.67 1.53 0.44 122.00 2.90 1.73 0.00
20.00 2.76 1.61 0.32 124.00 2.90 1.73 0.00
22.00 2.83 1.67 0.30 126.00 2.90 1.73 0.00
24.00 2.90 1.73 0.27 128.00 2.90 1.73 0.00
26.00 2.90 1.73 0.00 130.00 2.90 1.73 0.00
28.00 2.90 1.73 0.00 132.00 2.90 1.73 0.00
30.00 2.90 1.73 0.00 134.00 2.90 1.73 0.00
32.00 2.90 1.73 0.00 136.00 2.90 1.73 0.00
34.00 2.90 1.73 0.00 138.00 2.90 1.73 0.00
36.00 2.90 1.73 0.00 140.00 2.90 1.73 0.00
38.00 2.90 1.73 0.00 142.00 2.90 1.73 0.00
40.00 2.90 1.73 0.00 144.00 2.90 1.73 0.00
42.00 2.90 1.73 0.00 146.00 2.90 1.73 0.00
44.00 2.90 1.73 0.00 148.00 2.90 1.73 0.00
46.00 2.90 1.73 0.00 150.00 2.90 1.73 0.00
48.00 2.90 1.73 0.00 152.00 2.90 1.73 0.00
50.00 2.90 1.73 0.00 154.00 2.90 1.73 0.00
52.00 2.90 1.73 0.00 156.00 2.90 1.73 0.00
54.00 2.90 1.73 0.00 158.00 2.90 1.73 0.00
56.00 2.90 1.73 0.00 160.00 2.90 1.73 0.00
58.00 2.90 1.73 0.00 162.00 2.90 1.73 0.00
60.00 2.90 1.73 0.00 164.00 2.90 1.73 0.00
62.00 2.90 1.73 0.00 166.00 2.90 1.73 0.00
64.00 2.90 1.73 0.00 168.00 2.90 1.73 0.00
66.00 2.90 1.73 0.00 170.00 2.90 1.73 0.00
68.00 2.90 1.73 0.00 172.00 2.90 1.73 0.00
70.00 2.90 1.73 0.00 174.00 2.90 1.73 0.00
72.00 2.90 1.73 0.00 176.00 2.90 1.73 0.00
74.00 2.90 1.73 0.00 178.00 2.90 1.73 0.00
76.00 2.90 1.73 0.00 180.00 2.90 1.73 0.00
78.00 2.90 1.73 0.00 182.00 2.90 1.73 0.00
80.00 2.90 1.73 0.00 184.00 2.90 1.73 0.00
82.00 2.90 1.73 0.00 186.00 2.90 1.73 0.00
84.00 2.90 1.73 0.00 188.00 2.90 1.73 0.00
86.00 2.90 1.73 0.00 190.00 2.90 1.73 0.00
88.00 2.90 1.73 0.00 192.00 2.90 1.73 0.00
90.00 2.90 1.73 0.00 194.00 2.90 1.73 0.00
92.00 2.90 1.73 0.00 196.00 2.90 1.73 0.00
94.00 2.90 1.73 0.00 198.00 2.90 1.73 0.00
96.00 2.90 1.73 0.00 200.00 2.90 1.73 0.00
98.00 2.90 1.73 0.00
100.00 2.90 1.73 0.00
102.00 2.90 1.73 0.00

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP-4)
Inflow Area = 9.560 ac, Inflow Depth = 1.73" for 1-yr Concord event
Inflow = 30.15 cfs @ 11.96 hrs, Volume= 1.378 af
Outflow = 1.08 cfs @ 13.64 hrs, Volume= 1.378 af, Atten= 96%, Lag= 100.6 min
Primary = 1.08 cfs @ 13.64 hrs, Volume= 1.378 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 633.97' @ 13.64 hrs Surf.Area= 14,419 sf Storage= 36,448 cf
Plug-Flow detention time= 982.5 min calculated for 1.378 af(100% of inflow)
Center-of-Mass det. time= 982.9 min ( 1,798.1 - 815.2 )
Volume Invert Avail.Storage Storage Description
#1 631.00' 108,271 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.00 10,175 0 0
632.00 11,544 10,860 10,860
634.00 14,461 26,005 36,865
636.00 17,604 32,065 68,930
638.00 21,737 39,341 108,271
Device Routing Invert Outlet Devices
#1 Primary 628.30' 18.0" x 58.5' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 628.00' S= 0.0051 '/' Cc= 0.900 n= 0.013
#2 Device 1 631.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.153 0.214 0.276 0.337 0.368 0.459
#3 Device 1 633.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=1.08 cfs @ 13.64 hrs HW=633.97' (Free Discharge)
4-1=Culvert (Passes 1.08 cfs of 18.71 cfs potential flow)
2=Exfiltration (Custom Controls 0.27 cfs)
3=Orifice/Grate (Orifice Controls 0.80 cfs @ 4.09 fps)
4=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP-4)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 631.00 0.00 0.00 0.00
5.00 0.00 0 631.00 0.00 0.00 0.00
10.00 0.30 1,219 631.12 0.02 0.02 0.00
15.00 0.73 35,458 633.90 1.03 1.03 0.00
20.00 0.32 28,810 633.43 0.64 0.64 0.00
25.00 0.00 25,067 633.15 0.29 0.29 0.00
30.00 0.00 21,053 632.84 0.20 0.20 0.00
35.00 0.00 17,533 632.56 0.19 0.19 0.00
40.00 0.00 14,313 632.29 0.17 0.17 0.00
45.00 0.00 11,375 632.04 0.16 0.16 0.00
50.00 0.00 8,822 631.82 0.13 0.13 0.00
55.00 0.00 6,816 631.64 0.10 0.10 0.00
60.00 0.00 5,252 631.50 0.08 0.08 0.00
65.00 0.00 4,038 631.39 0.06 0.06 0.00
70.00 0.00 3,099 631.30 0.05 0.05 0.00
75.00 0.00 2,376 631.23 0.04 0.04 0.00
80.00 0.00 1,819 631.18 0.03 0.03 0.00
85.00 0.00 1,392 631.14 0.02 0.02 0.00
90.00 0.00 1,064 631.10 0.02 0.02 0.00
95.00 0.00 813 631.08 0.01 0.01 0.00
100.00 0.00 621 631.06 0.01 0.01 0.00
105.00 0.00 475 631.05 0.01 0.01 0.00
110.00 0.00 362 631.04 0.01 0.01 0.00
115.00 0.00 277 631.03 0.00 0.00 0.00
120.00 0.00 211 631.02 0.00 0.00 0.00
125.00 0.00 162 631.02 0.00 0.00 0.00
130.00 0.00 123 631.01 0.00 0.00 0.00
135.00 0.00 94 631.01 0.00 0.00 0.00
140.00 0.00 72 631.01 0.00 0.00 0.00
145.00 0.00 55 631.01 0.00 0.00 0.00
150.00 0.00 42 631.00 0.00 0.00 0.00
155.00 0.00 32 631.00 0.00 0.00 0.00
160.00 0.00 25 631.00 0.00 0.00 0.00
165.00 0.00 19 631.00 0.00 0.00 0.00
170.00 0.00 14 631.00 0.00 0.00 0.00
175.00 0.00 11 631.00 0.00 0.00 0.00
180.00 0.00 8 631.00 0.00 0.00 0.00
185.00 0.00 6 631.00 0.00 0.00 0.00
190.00 0.00 5 631.00 0.00 0.00 0.00
195.00 0.00 4 631.00 0.00 0.00 0.00
200.00 0.00 3 631.00 0.00 0.00 0.00

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP-4)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
631.00 0.00 0.00 0.00 636.20 4.93 4.93 0.00
631.10 0.02 0.02 0.00 636.30 7.42 7.42 0.00
631.20 0.03 0.03 0.00 636.40 10.35 10.35 0.00
631.30 0.05 0.05 0.00 636.50 13.68 13.68 0.00
631.40 0.06 0.06 0.00 636.60 17.35 17.35 0.00
631.50 0.08 0.08 0.00 636.70 21.34 21.34 0.00
631.60 0.09 0.09 0.00 636.80 23.69 23.69 0.00
631.70 0.11 0.11 0.00 636.90 23.84 23.84 0.00
631.80 0.12 0.12 0.00 637.00 23.99 23.99 0.00
631.90 0.14 0.14 0.00 637.10 24.99 24.14 0.85
632.00 0.15 0.15 0.00 637.20 26.69 24.29 2.40
632.10 0.16 0.16 0.00 637.30 28.86 24.44 4.42
632.20 0.17 0.17 0.00 637.40 31.42 24.59 6.83
632.30 0.17 0.17 0.00 637.50 34.28 24.73 9.55
632.40 0.18 0.18 0.00 637.60 37.43 24.88 12.55
632.50 0.18 0.18 0.00 637.70 40.66 25.03 15.64
632.60 0.19 0.19 0.00 637.80 44.06 25.17 18.89
632.70 0.20 0.20 0.00 637.90 47.81 25.31 22.50
632.80 0.20 0.20 0.00 638.00 51.76 25.46 26.30
632.90 0.21 0.21 0.00
633.00 0.21 0.21 0.00
633.10 0.25 0.25 0.00
633.20 0.34 0.34 0.00
633.30 0.46 0.46 0.00
633.40 0.60 0.60 0.00
633.50 0.72 0.72 0.00
633.60 0.81 0.81 0.00
633.70 0.89 0.89 0.00
633.80 0.96 0.96 0.00
633.90 1.03 1.03 0.00
634.00 1.09 1.09 0.00
634.10 1.15 1.15 0.00
634.20 1.21 1.21 0.00
634.30 1.26 1.26 0.00
634.40 1.31 1.31 0.00
634.50 1.36 1.36 0.00
634.60 1.41 1.41 0.00
634.70 1.46 1.46 0.00
634.80 1.50 1.50 0.00
634.90 1.55 1.55 0.00
635.00 1.59 1.59 0.00
635.10 1.63 1.63 0.00
635.20 1.66 1.66 0.00
635.30 1.70 1.70 0.00
635.40 1.74 1.74 0.00
635.50 1.77 1.77 0.00
635.60 1.80 1.80 0.00
635.70 1.84 1.84 0.00
635.80 1.87 1.87 0.00
635.90 1.90 1.90 0.00
636.00 1.94 1.94 0.00
636.10 3.01 3.01 0.00

2020.17-BMP4 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP-4)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
631.00 10,175 0 636.20 18,017 72,492
631.10 10,312 1,024 636.30 18,224 74,304
631.20 10,449 2,062 636.40 18,431 76,136
631.30 10,586 3,114 636.50 18,637 77,990
631.40 10,723 4,180 636.60 18,844 79,864
631.50 10,860 5,259 636.70 19,051 81,759
631.60 10,996 6,351 636.80 19,257 83,674
631.70 11,133 7,458 636.90 19,464 85,610
631.80 11,270 8,578 637.00 19,671 87,567
631.90 11,407 9,712 637.10 19,877 89,544
632.00 11,544 10,860 637.20 20,084 91,542
632.10 11,690 12,021 637.30 20,290 93,561
632.20 11,836 13,197 637.40 20,497 95,600
632.30 11,982 14,388 637.50 20,704 97,660
632.40 12,127 15,594 637.60 20,910 99,741
632.50 12,273 16,814 637.70 21,117 101,842
632.60 12,419 18,048 637.80 21,324 103,964
632.70 12,565 19,298 637.90 21,530 106,107
632.80 12,711 20,561 638.00 21,737 108,271
632.90 12,857 21,840
633.00 13,003 23,133
633.10 13,148 24,440
633.20 13,294 25,762
633.30 13,440 27,099
633.40 13,586 28,450
633.50 13,732 29,816
633.60 13,878 31,197
633.70 14,023 32,592
633.80 14,169 34,001
633.90 14,315 35,426
634.00 14,461 36,865
634.10 14,618 38,318
634.20 14,775 39,788
634.30 14,932 41,274
634.40 15,090 42,775
634.50 15,247 44,291
634.60 15,404 45,824
634.70 15,561 47,372
634.80 15,718 48,936
634.90 15,875 50,516
635.00 16,033 52,111
635.10 16,190 53,722
635.20 16,347 55,349
635.30 16,504 56,992
635.40 16,661 58,650
635.50 16,818 60,324
635.60 16,975 62,014
635.70 17,133 63,719
635.80 17,290 65,440
635.90 17,447 67,177
636.00 17,604 68,930
636.10 17,811 70,700

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.560 ac Runoff Depth=2.62"
Flow Length=512' Tc=14.6 min CN=76 Runoff=32.86 cfs 2.086 af
Subcatchment 2S: (Post Developed) Runoff Area=9.560 ac Runoff Depth=3.76"
Tc=5.0 min CN=88 Runoff=62.88 cfs 2.999 af
Pond 3P: (BMP-4) Peak Elev=636.27' Storage=73,698 cf Inflow=62.88 cfs 2.999 af
Primary=6.56 cfs 2.999 af Secondary=0.00 cfs 0.000 af Outflow=6.56 cfs 2.999 af
Total Runoff Area = 19.120 ac Runoff Volume = 5.084 af Average Runoff Depth = 3.19"
77.35% Pervious Area = 14.790 ac 22.65% Impervious Area = 4.330 ac

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 32.86 cfs @ 12.07 hrs, Volume= 2.086 af, Depth= 2.62"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
4.920 73 Woods, Fair, HSG C
4.640 79 Pasture/grassland/range, Fair, HSG C
9.560 76 Weighted Average
9.560 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 100 0.0439 0.17 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
4.6 412 0.0875 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.6 512 Total

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 2.62 0.00
2.00 0.11 0.00 0.00 106.00 5.10 2.62 0.00
4.00 0.24 0.00 0.00 108.00 5.10 2.62 0.00
6.00 0.41 0.00 0.00 110.00 5.10 2.62 0.00
8.00 0.61 0.00 0.00 112.00 5.10 2.62 0.00
10.00 0.92 0.02 0.25 114.00 5.10 2.62 0.00
12.00 3.38 1.28 27.56 116.00 5.10 2.62 0.00
14.00 4.18 1.88 1.58 118.00 5.10 2.62 0.00
16.00 4.49 2.12 0.96 120.00 5.10 2.62 0.00
18.00 4.70 2.29 0.74 122.00 5.10 2.62 0.00
20.00 4.86 2.42 0.54 124.00 5.10 2.62 0.00
22.00 4.98 2.52 0.49 126.00 5.10 2.62 0.00
24.00 5.10 2.62 0.45 128.00 5.10 2.62 0.00
26.00 5.10 2.62 0.00 130.00 5.10 2.62 0.00
28.00 5.10 2.62 0.00 132.00 5.10 2.62 0.00
30.00 5.10 2.62 0.00 134.00 5.10 2.62 0.00
32.00 5.10 2.62 0.00 136.00 5.10 2.62 0.00
34.00 5.10 2.62 0.00 138.00 5.10 2.62 0.00
36.00 5.10 2.62 0.00 140.00 5.10 2.62 0.00
38.00 5.10 2.62 0.00 142.00 5.10 2.62 0.00
40.00 5.10 2.62 0.00 144.00 5.10 2.62 0.00
42.00 5.10 2.62 0.00 146.00 5.10 2.62 0.00
44.00 5.10 2.62 0.00 148.00 5.10 2.62 0.00
46.00 5.10 2.62 0.00 150.00 5.10 2.62 0.00
48.00 5.10 2.62 0.00 152.00 5.10 2.62 0.00
50.00 5.10 2.62 0.00 154.00 5.10 2.62 0.00
52.00 5.10 2.62 0.00 156.00 5.10 2.62 0.00
54.00 5.10 2.62 0.00 158.00 5.10 2.62 0.00
56.00 5.10 2.62 0.00 160.00 5.10 2.62 0.00
58.00 5.10 2.62 0.00 162.00 5.10 2.62 0.00
60.00 5.10 2.62 0.00 164.00 5.10 2.62 0.00
62.00 5.10 2.62 0.00 166.00 5.10 2.62 0.00
64.00 5.10 2.62 0.00 168.00 5.10 2.62 0.00
66.00 5.10 2.62 0.00 170.00 5.10 2.62 0.00
68.00 5.10 2.62 0.00 172.00 5.10 2.62 0.00
70.00 5.10 2.62 0.00 174.00 5.10 2.62 0.00
72.00 5.10 2.62 0.00 176.00 5.10 2.62 0.00
74.00 5.10 2.62 0.00 178.00 5.10 2.62 0.00
76.00 5.10 2.62 0.00 180.00 5.10 2.62 0.00
78.00 5.10 2.62 0.00 182.00 5.10 2.62 0.00
80.00 5.10 2.62 0.00 184.00 5.10 2.62 0.00
82.00 5.10 2.62 0.00 186.00 5.10 2.62 0.00
84.00 5.10 2.62 0.00 188.00 5.10 2.62 0.00
86.00 5.10 2.62 0.00 190.00 5.10 2.62 0.00
88.00 5.10 2.62 0.00 192.00 5.10 2.62 0.00
90.00 5.10 2.62 0.00 194.00 5.10 2.62 0.00
92.00 5.10 2.62 0.00 196.00 5.10 2.62 0.00
94.00 5.10 2.62 0.00 198.00 5.10 2.62 0.00
96.00 5.10 2.62 0.00 200.00 5.10 2.62 0.00
98.00 5.10 2.62 0.00
100.00 5.10 2.62 0.00
102.00 5.10 2.62 0.00

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 62.88 cfs @ 11.96 hrs, Volume= 2.999 af, Depth= 3.76"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
4.330 98 Paved parking & roofs
5.230 79 50-75% Grass cover, Fair, HSG C
9.560 88 Weighted Average
5.230 Pervious Area
4.330 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.76 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.76 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.76 0.00
6.00 0.41 0.01 0.14 110.00 5.10 3.76 0.00
8.00 0.61 0.07 0.38 112.00 5.10 3.76 0.00
10.00 0.92 0.21 1.02 114.00 5.10 3.76 0.00
12.00 3.38 2.16 52.71 116.00 5.10 3.76 0.00
14.00 4.18 2.90 1.77 118.00 5.10 3.76 0.00
16.00 4.49 3.18 1.09 120.00 5.10 3.76 0.00
18.00 4.70 3.38 0.84 122.00 5.10 3.76 0.00
20.00 4.86 3.53 0.61 124.00 5.10 3.76 0.00
22.00 4.98 3.65 0.56 126.00 5.10 3.76 0.00
24.00 5.10 3.76 0.52 128.00 5.10 3.76 0.00
26.00 5.10 3.76 0.00 130.00 5.10 3.76 0.00
28.00 5.10 3.76 0.00 132.00 5.10 3.76 0.00
30.00 5.10 3.76 0.00 134.00 5.10 3.76 0.00
32.00 5.10 3.76 0.00 136.00 5.10 3.76 0.00
34.00 5.10 3.76 0.00 138.00 5.10 3.76 0.00
36.00 5.10 3.76 0.00 140.00 5.10 3.76 0.00
38.00 5.10 3.76 0.00 142.00 5.10 3.76 0.00
40.00 5.10 3.76 0.00 144.00 5.10 3.76 0.00
42.00 5.10 3.76 0.00 146.00 5.10 3.76 0.00
44.00 5.10 3.76 0.00 148.00 5.10 3.76 0.00
46.00 5.10 3.76 0.00 150.00 5.10 3.76 0.00
48.00 5.10 3.76 0.00 152.00 5.10 3.76 0.00
50.00 5.10 3.76 0.00 154.00 5.10 3.76 0.00
52.00 5.10 3.76 0.00 156.00 5.10 3.76 0.00
54.00 5.10 3.76 0.00 158.00 5.10 3.76 0.00
56.00 5.10 3.76 0.00 160.00 5.10 3.76 0.00
58.00 5.10 3.76 0.00 162.00 5.10 3.76 0.00
60.00 5.10 3.76 0.00 164.00 5.10 3.76 0.00
62.00 5.10 3.76 0.00 166.00 5.10 3.76 0.00
64.00 5.10 3.76 0.00 168.00 5.10 3.76 0.00
66.00 5.10 3.76 0.00 170.00 5.10 3.76 0.00
68.00 5.10 3.76 0.00 172.00 5.10 3.76 0.00
70.00 5.10 3.76 0.00 174.00 5.10 3.76 0.00
72.00 5.10 3.76 0.00 176.00 5.10 3.76 0.00
74.00 5.10 3.76 0.00 178.00 5.10 3.76 0.00
76.00 5.10 3.76 0.00 180.00 5.10 3.76 0.00
78.00 5.10 3.76 0.00 182.00 5.10 3.76 0.00
80.00 5.10 3.76 0.00 184.00 5.10 3.76 0.00
82.00 5.10 3.76 0.00 186.00 5.10 3.76 0.00
84.00 5.10 3.76 0.00 188.00 5.10 3.76 0.00
86.00 5.10 3.76 0.00 190.00 5.10 3.76 0.00
88.00 5.10 3.76 0.00 192.00 5.10 3.76 0.00
90.00 5.10 3.76 0.00 194.00 5.10 3.76 0.00
92.00 5.10 3.76 0.00 196.00 5.10 3.76 0.00
94.00 5.10 3.76 0.00 198.00 5.10 3.76 0.00
96.00 5.10 3.76 0.00 200.00 5.10 3.76 0.00
98.00 5.10 3.76 0.00
100.00 5.10 3.76 0.00
102.00 5.10 3.76 0.00

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP-4)
Inflow Area = 9.560 ac, Inflow Depth = 3.76" for 10-yr Concord event
Inflow = 62.88 cfs @ 11.96 hrs, Volume= 2.999 af
Outflow = 6.56 cfs @ 12.32 hrs, Volume= 2.999 af, Atten= 90%, Lag= 21.7 min
Primary = 6.56 cfs @ 12.32 hrs, Volume= 2.999 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 636.27' @ 12.32 hrs Surf.Area= 18,155 sf Storage= 73,698 cf
Plug-Flow detention time= 686.7 min calculated for 2.999 af(100% of inflow)
Center-of-Mass det. time= 686.7 min ( 1,479.8 - 793.1 )
Volume Invert Avail.Storage Storage Description
#1 631.00' 108,271 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.00 10,175 0 0
632.00 11,544 10,860 10,860
634.00 14,461 26,005 36,865
636.00 17,604 32,065 68,930
638.00 21,737 39,341 108,271
Device Routing Invert Outlet Devices
#1 Primary 628.30' 18.0" x 58.5' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 628.00' S= 0.0051 '/' Cc= 0.900 n= 0.013
#2 Device 1 631.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.153 0.214 0.276 0.337 0.368 0.459
#3 Device 1 633.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=6.54 cfs @ 12.32 hrs HW=636.27' (Free Discharge)
4-1=Culvert (Passes 6.54 cfs of 22.86 cfs potential flow)
2=Exfiltration (Custom Controls 0.39 cfs)
3=Orifice/Grate (Orifice Controls 1.64 cfs @ 8.36 fps)
4=Top of Riser (Weir Controls 4.50 cfs @ 1.69 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP-4)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 631.00 0.00 0.00 0.00
5.00 0.05 44 631.00 0.00 0.00 0.00
10.00 1.02 6,453 631.61 0.09 0.09 0.00
15.00 1.41 68,050 635.95 1.92 1.92 0.00
20.00 0.61 52,676 635.04 1.60 1.60 0.00
25.00 0.00 36,354 633.96 1.07 1.07 0.00
30.00 0.00 24,926 633.14 0.28 0.28 0.00
35.00 0.00 20,951 632.83 0.20 0.20 0.00
40.00 0.00 17,440 632.55 0.19 0.19 0.00
45.00 0.00 14,228 632.29 0.17 0.17 0.00
50.00 0.00 11,297 632.04 0.16 0.16 0.00
55.00 0.00 8,760 631.82 0.12 0.12 0.00
60.00 0.00 6,767 631.64 0.10 0.10 0.00
65.00 0.00 5,214 631.50 0.08 0.08 0.00
70.00 0.00 4,009 631.38 0.06 0.06 0.00
75.00 0.00 3,077 631.30 0.05 0.05 0.00
80.00 0.00 2,358 631.23 0.03 0.03 0.00
85.00 0.00 1,806 631.18 0.03 0.03 0.00
90.00 0.00 1,381 631.13 0.02 0.02 0.00
95.00 0.00 1,056 631.10 0.02 0.02 0.00
100.00 0.00 807 631.08 0.01 0.01 0.00
105.00 0.00 617 631.06 0.01 0.01 0.00
110.00 0.00 471 631.05 0.01 0.01 0.00
115.00 0.00 360 631.04 0.01 0.01 0.00
120.00 0.00 275 631.03 0.00 0.00 0.00
125.00 0.00 210 631.02 0.00 0.00 0.00
130.00 0.00 160 631.02 0.00 0.00 0.00
135.00 0.00 122 631.01 0.00 0.00 0.00
140.00 0.00 94 631.01 0.00 0.00 0.00
145.00 0.00 71 631.01 0.00 0.00 0.00
150.00 0.00 55 631.01 0.00 0.00 0.00
155.00 0.00 42 631.00 0.00 0.00 0.00
160.00 0.00 32 631.00 0.00 0.00 0.00
165.00 0.00 24 631.00 0.00 0.00 0.00
170.00 0.00 19 631.00 0.00 0.00 0.00
175.00 0.00 14 631.00 0.00 0.00 0.00
180.00 0.00 11 631.00 0.00 0.00 0.00
185.00 0.00 8 631.00 0.00 0.00 0.00
190.00 0.00 6 631.00 0.00 0.00 0.00
195.00 0.00 5 631.00 0.00 0.00 0.00
200.00 0.00 4 631.00 0.00 0.00 0.00

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP-4)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
631.00 0.00 0.00 0.00 636.20 4.93 4.93 0.00
631.10 0.02 0.02 0.00 636.30 7.42 7.42 0.00
631.20 0.03 0.03 0.00 636.40 10.35 10.35 0.00
631.30 0.05 0.05 0.00 636.50 13.68 13.68 0.00
631.40 0.06 0.06 0.00 636.60 17.35 17.35 0.00
631.50 0.08 0.08 0.00 636.70 21.34 21.34 0.00
631.60 0.09 0.09 0.00 636.80 23.69 23.69 0.00
631.70 0.11 0.11 0.00 636.90 23.84 23.84 0.00
631.80 0.12 0.12 0.00 637.00 23.99 23.99 0.00
631.90 0.14 0.14 0.00 637.10 24.99 24.14 0.85
632.00 0.15 0.15 0.00 637.20 26.69 24.29 2.40
632.10 0.16 0.16 0.00 637.30 28.86 24.44 4.42
632.20 0.17 0.17 0.00 637.40 31.42 24.59 6.83
632.30 0.17 0.17 0.00 637.50 34.28 24.73 9.55
632.40 0.18 0.18 0.00 637.60 37.43 24.88 12.55
632.50 0.18 0.18 0.00 637.70 40.66 25.03 15.64
632.60 0.19 0.19 0.00 637.80 44.06 25.17 18.89
632.70 0.20 0.20 0.00 637.90 47.81 25.31 22.50
632.80 0.20 0.20 0.00 638.00 51.76 25.46 26.30
632.90 0.21 0.21 0.00
633.00 0.21 0.21 0.00
633.10 0.25 0.25 0.00
633.20 0.34 0.34 0.00
633.30 0.46 0.46 0.00
633.40 0.60 0.60 0.00
633.50 0.72 0.72 0.00
633.60 0.81 0.81 0.00
633.70 0.89 0.89 0.00
633.80 0.96 0.96 0.00
633.90 1.03 1.03 0.00
634.00 1.09 1.09 0.00
634.10 1.15 1.15 0.00
634.20 1.21 1.21 0.00
634.30 1.26 1.26 0.00
634.40 1.31 1.31 0.00
634.50 1.36 1.36 0.00
634.60 1.41 1.41 0.00
634.70 1.46 1.46 0.00
634.80 1.50 1.50 0.00
634.90 1.55 1.55 0.00
635.00 1.59 1.59 0.00
635.10 1.63 1.63 0.00
635.20 1.66 1.66 0.00
635.30 1.70 1.70 0.00
635.40 1.74 1.74 0.00
635.50 1.77 1.77 0.00
635.60 1.80 1.80 0.00
635.70 1.84 1.84 0.00
635.80 1.87 1.87 0.00
635.90 1.90 1.90 0.00
636.00 1.94 1.94 0.00
636.10 3.01 3.01 0.00

2020.17-BMP4 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP-4)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
631.00 10,175 0 636.20 18,017 72,492
631.10 10,312 1,024 636.30 18,224 74,304
631.20 10,449 2,062 636.40 18,431 76,136
631.30 10,586 3,114 636.50 18,637 77,990
631.40 10,723 4,180 636.60 18,844 79,864
631.50 10,860 5,259 636.70 19,051 81,759
631.60 10,996 6,351 636.80 19,257 83,674
631.70 11,133 7,458 636.90 19,464 85,610
631.80 11,270 8,578 637.00 19,671 87,567
631.90 11,407 9,712 637.10 19,877 89,544
632.00 11,544 10,860 637.20 20,084 91,542
632.10 11,690 12,021 637.30 20,290 93,561
632.20 11,836 13,197 637.40 20,497 95,600
632.30 11,982 14,388 637.50 20,704 97,660
632.40 12,127 15,594 637.60 20,910 99,741
632.50 12,273 16,814 637.70 21,117 101,842
632.60 12,419 18,048 637.80 21,324 103,964
632.70 12,565 19,298 637.90 21,530 106,107
632.80 12,711 20,561 638.00 21,737 108,271
632.90 12,857 21,840
633.00 13,003 23,133
633.10 13,148 24,440
633.20 13,294 25,762
633.30 13,440 27,099
633.40 13,586 28,450
633.50 13,732 29,816
633.60 13,878 31,197
633.70 14,023 32,592
633.80 14,169 34,001
633.90 14,315 35,426
634.00 14,461 36,865
634.10 14,618 38,318
634.20 14,775 39,788
634.30 14,932 41,274
634.40 15,090 42,775
634.50 15,247 44,291
634.60 15,404 45,824
634.70 15,561 47,372
634.80 15,718 48,936
634.90 15,875 50,516
635.00 16,033 52,111
635.10 16,190 53,722
635.20 16,347 55,349
635.30 16,504 56,992
635.40 16,661 58,650
635.50 16,818 60,324
635.60 16,975 62,014
635.70 17,133 63,719
635.80 17,290 65,440
635.90 17,447 67,177
636.00 17,604 68,930
636.10 17,811 70,700

2020.17-BMP4 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.560 ac Runoff Depth=3.38"
Flow Length=512' Tc=14.6 min CN=76 Runoff=42.38 cfs 2.693 af
Subcatchment 2S: (Post Developed) Runoff Area=9.560 ac Runoff Depth=4.63"
Tc=5.0 min CN=88 Runoff=76.24 cfs 3.685 af
Pond 3P: (BMP-4) Peak Elev=636.76' Storage=82,994 cf Inflow=76.24 cfs 3.685 af
Primary=23.26 cfs 3.685 af Secondary=0.00 cfs 0.000 af Outflow=23.26 cfs 3.685 af
Total Runoff Area = 19.120 ac Runoff Volume = 6.378 af Average Runoff Depth = 4.00"
77.35% Pervious Area = 14.790 ac 22.65% Impervious Area = 4.330 ac

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 42.38 cfs @ 12.07 hrs, Volume= 2.693 af, Depth= 3.38"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
4.920 73 Woods, Fair, HSG C
_ 4.640 79 Pasture/grassland/range, Fair, HSG C
9.560 76 Weighted Average
9.560 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 100 0.0439 0.17 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
4.6 412 0.0875 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.6 512 Total

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 3.38 0.00
2.00 0.13 0.00 0.00 106.00 6.00 3.38 0.00
4.00 0.29 0.00 0.00 108.00 6.00 3.38 0.00
6.00 0.48 0.00 0.00 110.00 6.00 3.38 0.00
8.00 0.72 0.00 0.05 112.00 6.00 3.38 0.00
10.00 1.09 0.06 0.45 114.00 6.00 3.38 0.00
12.00 3.98 1.72 35.97 116.00 6.00 3.38 0.00
14.00 4.92 2.47 1.96 118.00 6.00 3.38 0.00
16.00 5.28 2.77 1.19 120.00 6.00 3.38 0.00
18.00 5.53 2.97 0.91 122.00 6.00 3.38 0.00
20.00 5.71 3.13 0.67 124.00 6.00 3.38 0.00
22.00 5.86 3.26 0.60 126.00 6.00 3.38 0.00
24.00 6.00 3.38 0.55 128.00 6.00 3.38 0.00
26.00 6.00 3.38 0.00 130.00 6.00 3.38 0.00
28.00 6.00 3.38 0.00 132.00 6.00 3.38 0.00
30.00 6.00 3.38 0.00 134.00 6.00 3.38 0.00
32.00 6.00 3.38 0.00 136.00 6.00 3.38 0.00
34.00 6.00 3.38 0.00 138.00 6.00 3.38 0.00
36.00 6.00 3.38 0.00 140.00 6.00 3.38 0.00
38.00 6.00 3.38 0.00 142.00 6.00 3.38 0.00
40.00 6.00 3.38 0.00 144.00 6.00 3.38 0.00
42.00 6.00 3.38 0.00 146.00 6.00 3.38 0.00
44.00 6.00 3.38 0.00 148.00 6.00 3.38 0.00
46.00 6.00 3.38 0.00 150.00 6.00 3.38 0.00
48.00 6.00 3.38 0.00 152.00 6.00 3.38 0.00
50.00 6.00 3.38 0.00 154.00 6.00 3.38 0.00
52.00 6.00 3.38 0.00 156.00 6.00 3.38 0.00
54.00 6.00 3.38 0.00 158.00 6.00 3.38 0.00
56.00 6.00 3.38 0.00 160.00 6.00 3.38 0.00
58.00 6.00 3.38 0.00 162.00 6.00 3.38 0.00
60.00 6.00 3.38 0.00 164.00 6.00 3.38 0.00
62.00 6.00 3.38 0.00 166.00 6.00 3.38 0.00
64.00 6.00 3.38 0.00 168.00 6.00 3.38 0.00
66.00 6.00 3.38 0.00 170.00 6.00 3.38 0.00
68.00 6.00 3.38 0.00 172.00 6.00 3.38 0.00
70.00 6.00 3.38 0.00 174.00 6.00 3.38 0.00
72.00 6.00 3.38 0.00 176.00 6.00 3.38 0.00
74.00 6.00 3.38 0.00 178.00 6.00 3.38 0.00
76.00 6.00 3.38 0.00 180.00 6.00 3.38 0.00
78.00 6.00 3.38 0.00 182.00 6.00 3.38 0.00
80.00 6.00 3.38 0.00 184.00 6.00 3.38 0.00
82.00 6.00 3.38 0.00 186.00 6.00 3.38 0.00
84.00 6.00 3.38 0.00 188.00 6.00 3.38 0.00
86.00 6.00 3.38 0.00 190.00 6.00 3.38 0.00
88.00 6.00 3.38 0.00 192.00 6.00 3.38 0.00
90.00 6.00 3.38 0.00 194.00 6.00 3.38 0.00
92.00 6.00 3.38 0.00 196.00 6.00 3.38 0.00
94.00 6.00 3.38 0.00 198.00 6.00 3.38 0.00
96.00 6.00 3.38 0.00 200.00 6.00 3.38 0.00
98.00 6.00 3.38 0.00
100.00 6.00 3.38 0.00
102.00 6.00 3.38 0.00

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 76.24 cfs @ 11.96 hrs, Volume= 3.685 af, Depth= 4.63"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
4.330 98 Paved parking & roofs
5.230 79 50-75% Grass cover, Fair, HSG C
9.560 88 Weighted Average
5.230 Pervious Area
4.330 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 4.63 0.00
2.00 0.13 0.00 0.00 106.00 6.00 4.63 0.00
4.00 0.29 0.00 0.01 108.00 6.00 4.63 0.00
6.00 0.48 0.03 0.25 110.00 6.00 4.63 0.00
8.00 0.72 0.11 0.54 112.00 6.00 4.63 0.00
10.00 1.09 0.30 1.35 114.00 6.00 4.63 0.00
12.00 3.98 2.71 63.70 116.00 6.00 4.63 0.00
14.00 4.92 3.59 2.11 118.00 6.00 4.63 0.00
16.00 5.28 3.94 1.30 120.00 6.00 4.63 0.00
18.00 5.53 4.17 1.01 122.00 6.00 4.63 0.00
20.00 5.71 4.35 0.73 124.00 6.00 4.63 0.00
22.00 5.86 4.49 0.67 126.00 6.00 4.63 0.00
24.00 6.00 4.63 0.61 128.00 6.00 4.63 0.00
26.00 6.00 4.63 0.00 130.00 6.00 4.63 0.00
28.00 6.00 4.63 0.00 132.00 6.00 4.63 0.00
30.00 6.00 4.63 0.00 134.00 6.00 4.63 0.00
32.00 6.00 4.63 0.00 136.00 6.00 4.63 0.00
34.00 6.00 4.63 0.00 138.00 6.00 4.63 0.00
36.00 6.00 4.63 0.00 140.00 6.00 4.63 0.00
38.00 6.00 4.63 0.00 142.00 6.00 4.63 0.00
40.00 6.00 4.63 0.00 144.00 6.00 4.63 0.00
42.00 6.00 4.63 0.00 146.00 6.00 4.63 0.00
44.00 6.00 4.63 0.00 148.00 6.00 4.63 0.00
46.00 6.00 4.63 0.00 150.00 6.00 4.63 0.00
48.00 6.00 4.63 0.00 152.00 6.00 4.63 0.00
50.00 6.00 4.63 0.00 154.00 6.00 4.63 0.00
52.00 6.00 4.63 0.00 156.00 6.00 4.63 0.00
54.00 6.00 4.63 0.00 158.00 6.00 4.63 0.00
56.00 6.00 4.63 0.00 160.00 6.00 4.63 0.00
58.00 6.00 4.63 0.00 162.00 6.00 4.63 0.00
60.00 6.00 4.63 0.00 164.00 6.00 4.63 0.00
62.00 6.00 4.63 0.00 166.00 6.00 4.63 0.00
64.00 6.00 4.63 0.00 168.00 6.00 4.63 0.00
66.00 6.00 4.63 0.00 170.00 6.00 4.63 0.00
68.00 6.00 4.63 0.00 172.00 6.00 4.63 0.00
70.00 6.00 4.63 0.00 174.00 6.00 4.63 0.00
72.00 6.00 4.63 0.00 176.00 6.00 4.63 0.00
74.00 6.00 4.63 0.00 178.00 6.00 4.63 0.00
76.00 6.00 4.63 0.00 180.00 6.00 4.63 0.00
78.00 6.00 4.63 0.00 182.00 6.00 4.63 0.00
80.00 6.00 4.63 0.00 184.00 6.00 4.63 0.00
82.00 6.00 4.63 0.00 186.00 6.00 4.63 0.00
84.00 6.00 4.63 0.00 188.00 6.00 4.63 0.00
86.00 6.00 4.63 0.00 190.00 6.00 4.63 0.00
88.00 6.00 4.63 0.00 192.00 6.00 4.63 0.00
90.00 6.00 4.63 0.00 194.00 6.00 4.63 0.00
92.00 6.00 4.63 0.00 196.00 6.00 4.63 0.00
94.00 6.00 4.63 0.00 198.00 6.00 4.63 0.00
96.00 6.00 4.63 0.00 200.00 6.00 4.63 0.00
98.00 6.00 4.63 0.00
100.00 6.00 4.63 0.00
102.00 6.00 4.63 0.00

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP-4)
Inflow Area = 9.560 ac, Inflow Depth = 4.63" for 25-yr Concord event
Inflow = 76.24 cfs @ 11.96 hrs, Volume= 3.685 af
Outflow = 23.26 cfs @ 12.07 hrs, Volume= 3.685 af, Atten= 69%, Lag= 6.8 min
Primary = 23.26 cfs @ 12.07 hrs, Volume= 3.685 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 636.76' @ 12.07 hrs Surf.Area= 19,184 sf Storage= 82,994 cf
Plug-Flow detention time= 587.4 min calculated for 3.685 af(100% of inflow)
Center-of-Mass det. time= 587.9 min ( 1,375.2 - 787.3 )
Volume Invert Avail.Storage Storage Description
#1 631.00' 108,271 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.00 10,175 0 0
632.00 11,544 10,860 10,860
634.00 14,461 26,005 36,865
636.00 17,604 32,065 68,930
638.00 21,737 39,341 108,271
Device Routing Invert Outlet Devices
#1 Primary 628.30' 18.0" x 58.5' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 628.00' S= 0.0051 '/' Cc= 0.900 n= 0.013
#2 Device 1 631.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.153 0.214 0.276 0.337 0.368 0.459
#3 Device 1 633.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=23.63 cfs @ 12.07 hrs HW=636.76' (Free Discharge)
4-1=Culvert (Inlet Controls 23.63 cfs @ 13.37 fps)
2=Exfiltration (Passes < 0.44 cfs potential flow)
3=Orifice/Grate (Passes < 1.77 cfs potential flow)
4=Top of Riser (Passes < 21.84 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=631.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP-4)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 631.00 0.00 0.00 0.00
5.00 0.12 223 631.02 0.00 0.00 0.00
10.00 1.35 9,298 631.86 0.13 0.13 0.00
15.00 1.68 68,973 636.00 1.95 1.95 0.00
20.00 0.73 55,938 635.24 1.68 1.68 0.00
25.00 0.00 39,354 634.17 1.19 1.19 0.00
30.00 0.00 25,736 633.20 0.34 0.34 0.00
35.00 0.00 21,494 632.87 0.21 0.21 0.00
40.00 0.00 17,938 632.59 0.19 0.19 0.00
45.00 0.00 14,682 632.32 0.17 0.17 0.00
50.00 0.00 11,711 632.07 0.16 0.16 0.00
55.00 0.00 9,096 631.85 0.13 0.13 0.00
60.00 0.00 7,030 631.66 0.10 0.10 0.00
65.00 0.00 5,419 631.51 0.08 0.08 0.00
70.00 0.00 4,167 631.40 0.06 0.06 0.00
75.00 0.00 3,199 631.31 0.05 0.05 0.00
80.00 0.00 2,453 631.24 0.04 0.04 0.00
85.00 0.00 1,878 631.18 0.03 0.03 0.00
90.00 0.00 1,437 631.14 0.02 0.02 0.00
95.00 0.00 1,099 631.11 0.02 0.02 0.00
100.00 0.00 840 631.08 0.01 0.01 0.00
105.00 0.00 642 631.06 0.01 0.01 0.00
110.00 0.00 490 631.05 0.01 0.01 0.00
115.00 0.00 374 631.04 0.01 0.01 0.00
120.00 0.00 286 631.03 0.00 0.00 0.00
125.00 0.00 218 631.02 0.00 0.00 0.00
130.00 0.00 167 631.02 0.00 0.00 0.00
135.00 0.00 127 631.01 0.00 0.00 0.00
140.00 0.00 97 631.01 0.00 0.00 0.00
145.00 0.00 74 631.01 0.00 0.00 0.00
150.00 0.00 57 631.01 0.00 0.00 0.00
155.00 0.00 43 631.00 0.00 0.00 0.00
160.00 0.00 33 631.00 0.00 0.00 0.00
165.00 0.00 25 631.00 0.00 0.00 0.00
170.00 0.00 19 631.00 0.00 0.00 0.00
175.00 0.00 15 631.00 0.00 0.00 0.00
180.00 0.00 11 631.00 0.00 0.00 0.00
185.00 0.00 9 631.00 0.00 0.00 0.00
190.00 0.00 7 631.00 0.00 0.00 0.00
195.00 0.00 5 631.00 0.00 0.00 0.00
200.00 0.00 4 631.00 0.00 0.00 0.00

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP-4)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
631.00 0.00 0.00 0.00 636.20 4.93 4.93 0.00
631.10 0.02 0.02 0.00 636.30 7.42 7.42 0.00
631.20 0.03 0.03 0.00 636.40 10.35 10.35 0.00
631.30 0.05 0.05 0.00 636.50 13.68 13.68 0.00
631.40 0.06 0.06 0.00 636.60 17.35 17.35 0.00
631.50 0.08 0.08 0.00 636.70 21.34 21.34 0.00
631.60 0.09 0.09 0.00 636.80 23.69 23.69 0.00
631.70 0.11 0.11 0.00 636.90 23.84 23.84 0.00
631.80 0.12 0.12 0.00 637.00 23.99 23.99 0.00
631.90 0.14 0.14 0.00 637.10 24.99 24.14 0.85
632.00 0.15 0.15 0.00 637.20 26.69 24.29 2.40
632.10 0.16 0.16 0.00 637.30 28.86 24.44 4.42
632.20 0.17 0.17 0.00 637.40 31.42 24.59 6.83
632.30 0.17 0.17 0.00 637.50 34.28 24.73 9.55
632.40 0.18 0.18 0.00 637.60 37.43 24.88 12.55
632.50 0.18 0.18 0.00 637.70 40.66 25.03 15.64
632.60 0.19 0.19 0.00 637.80 44.06 25.17 18.89
632.70 0.20 0.20 0.00 637.90 47.81 25.31 22.50
632.80 0.20 0.20 0.00 638.00 51.76 25.46 26.30
632.90 0.21 0.21 0.00
633.00 0.21 0.21 0.00
633.10 0.25 0.25 0.00
633.20 0.34 0.34 0.00
633.30 0.46 0.46 0.00
633.40 0.60 0.60 0.00
633.50 0.72 0.72 0.00
633.60 0.81 0.81 0.00
633.70 0.89 0.89 0.00
633.80 0.96 0.96 0.00
633.90 1.03 1.03 0.00
634.00 1.09 1.09 0.00
634.10 1.15 1.15 0.00
634.20 1.21 1.21 0.00
634.30 1.26 1.26 0.00
634.40 1.31 1.31 0.00
634.50 1.36 1.36 0.00
634.60 1.41 1.41 0.00
634.70 1.46 1.46 0.00
634.80 1.50 1.50 0.00
634.90 1.55 1.55 0.00
635.00 1.59 1.59 0.00
635.10 1.63 1.63 0.00
635.20 1.66 1.66 0.00
635.30 1.70 1.70 0.00
635.40 1.74 1.74 0.00
635.50 1.77 1.77 0.00
635.60 1.80 1.80 0.00
635.70 1.84 1.84 0.00
635.80 1.87 1.87 0.00
635.90 1.90 1.90 0.00
636.00 1.94 1.94 0.00
636.10 3.01 3.01 0.00

2020.17-BMP4 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP-4)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
631.00 10,175 0 636.20 18,017 72,492
631.10 10,312 1,024 636.30 18,224 74,304
631.20 10,449 2,062 636.40 18,431 76,136
631.30 10,586 3,114 636.50 18,637 77,990
631.40 10,723 4,180 636.60 18,844 79,864
631.50 10,860 5,259 636.70 19,051 81,759
631.60 10,996 6,351 636.80 19,257 83,674
631.70 11,133 7,458 636.90 19,464 85,610
631.80 11,270 8,578 637.00 19,671 87,567
631.90 11,407 9,712 637.10 19,877 89,544
632.00 11,544 10,860 637.20 20,084 91,542
632.10 11,690 12,021 637.30 20,290 93,561
632.20 11,836 13,197 637.40 20,497 95,600
632.30 11,982 14,388 637.50 20,704 97,660
632.40 12,127 15,594 637.60 20,910 99,741
632.50 12,273 16,814 637.70 21,117 101,842
632.60 12,419 18,048 637.80 21,324 103,964
632.70 12,565 19,298 637.90 21,530 106,107
632.80 12,711 20,561 638.00 21,737 108,271
632.90 12,857 21,840
633.00 13,003 23,133
633.10 13,148 24,440
633.20 13,294 25,762
633.30 13,440 27,099
633.40 13,586 28,450
633.50 13,732 29,816
633.60 13,878 31,197
633.70 14,023 32,592
633.80 14,169 34,001
633.90 14,315 35,426
634.00 14,461 36,865
634.10 14,618 38,318
634.20 14,775 39,788
634.30 14,932 41,274
634.40 15,090 42,775
634.50 15,247 44,291
634.60 15,404 45,824
634.70 15,561 47,372
634.80 15,718 48,936
634.90 15,875 50,516
635.00 16,033 52,111
635.10 16,190 53,722
635.20 16,347 55,349
635.30 16,504 56,992
635.40 16,661 58,650
635.50 16,818 60,324
635.60 16,975 62,014
635.70 17,133 63,719
635.80 17,290 65,440
635.90 17,447 67,177
636.00 17,604 68,930
636.10 17,811 70,700

2020.17-BMP4 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.560 ac Runoff Depth=4.08"
Flow Length=512' Tc=14.6 min CN=76 Runoff=51.00 cfs 3.250 af
Subcatchment 2S: (Post Developed) Runoff Area=9.560 ac Runoff Depth=5.40"
Tc=5.0 min CN=88 Runoff=88.05 cfs 4.301 af
Pond 3P: (BMP-4) Peak Elev=637.31' Storage=93,774 cf Inflow=88.05 cfs 4.301 af
Primary=24.46 cfs 4.257 af Secondary=4.67 cfs 0.045 af Outflow=29.12 cfs 4.301 af
Total Runoff Area = 19.120 ac Runoff Volume = 7.552 af Average Runoff Depth = 4.74"
77.35% Pervious Area = 14.790 ac 22.65% Impervious Area = 4.330 ac

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 51.00 cfs @ 12.06 hrs, Volume= 3.250 af, Depth= 4.08"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
4.920 73 Woods, Fair, HSG C
4.640 79 Pasture/grassland/range, Fair, HSG C
9.560 76 Weighted Average
9.560 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
10.0 100 0.0439 0.17 Sheet Flow,
Grass: Dense n= 0.240 P2= 3.50"
4.6 412 0.0875 1.48 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
14.6 512 Total

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 4.08 0.00
2.00 0.15 0.00 0.00 106.00 6.80 4.08 0.00
4.00 0.33 0.00 0.00 108.00 6.80 4.08 0.00
6.00 0.54 0.00 0.00 110.00 6.80 4.08 0.00
8.00 0.82 0.01 0.13 112.00 6.80 4.08 0.00
10.00 1.23 0.10 0.65 114.00 6.80 4.08 0.00
12.00 4.51 2.14 43.62 116.00 6.80 4.08 0.00
14.00 5.58 3.02 2.30 118.00 6.80 4.08 0.00
16.00 5.98 3.37 1.39 120.00 6.80 4.08 0.00
18.00 6.26 3.61 1.06 122.00 6.80 4.08 0.00
20.00 6.47 3.79 0.78 124.00 6.80 4.08 0.00
22.00 6.64 3.94 0.70 126.00 6.80 4.08 0.00
24.00 6.80 4.08 0.64 128.00 6.80 4.08 0.00
26.00 6.80 4.08 0.00 130.00 6.80 4.08 0.00
28.00 6.80 4.08 0.00 132.00 6.80 4.08 0.00
30.00 6.80 4.08 0.00 134.00 6.80 4.08 0.00
32.00 6.80 4.08 0.00 136.00 6.80 4.08 0.00
34.00 6.80 4.08 0.00 138.00 6.80 4.08 0.00
36.00 6.80 4.08 0.00 140.00 6.80 4.08 0.00
38.00 6.80 4.08 0.00 142.00 6.80 4.08 0.00
40.00 6.80 4.08 0.00 144.00 6.80 4.08 0.00
42.00 6.80 4.08 0.00 146.00 6.80 4.08 0.00
44.00 6.80 4.08 0.00 148.00 6.80 4.08 0.00
46.00 6.80 4.08 0.00 150.00 6.80 4.08 0.00
48.00 6.80 4.08 0.00 152.00 6.80 4.08 0.00
50.00 6.80 4.08 0.00 154.00 6.80 4.08 0.00
52.00 6.80 4.08 0.00 156.00 6.80 4.08 0.00
54.00 6.80 4.08 0.00 158.00 6.80 4.08 0.00
56.00 6.80 4.08 0.00 160.00 6.80 4.08 0.00
58.00 6.80 4.08 0.00 162.00 6.80 4.08 0.00
60.00 6.80 4.08 0.00 164.00 6.80 4.08 0.00
62.00 6.80 4.08 0.00 166.00 6.80 4.08 0.00
64.00 6.80 4.08 0.00 168.00 6.80 4.08 0.00
66.00 6.80 4.08 0.00 170.00 6.80 4.08 0.00
68.00 6.80 4.08 0.00 172.00 6.80 4.08 0.00
70.00 6.80 4.08 0.00 174.00 6.80 4.08 0.00
72.00 6.80 4.08 0.00 176.00 6.80 4.08 0.00
74.00 6.80 4.08 0.00 178.00 6.80 4.08 0.00
76.00 6.80 4.08 0.00 180.00 6.80 4.08 0.00
78.00 6.80 4.08 0.00 182.00 6.80 4.08 0.00
80.00 6.80 4.08 0.00 184.00 6.80 4.08 0.00
82.00 6.80 4.08 0.00 186.00 6.80 4.08 0.00
84.00 6.80 4.08 0.00 188.00 6.80 4.08 0.00
86.00 6.80 4.08 0.00 190.00 6.80 4.08 0.00
88.00 6.80 4.08 0.00 192.00 6.80 4.08 0.00
90.00 6.80 4.08 0.00 194.00 6.80 4.08 0.00
92.00 6.80 4.08 0.00 196.00 6.80 4.08 0.00
94.00 6.80 4.08 0.00 198.00 6.80 4.08 0.00
96.00 6.80 4.08 0.00 200.00 6.80 4.08 0.00
98.00 6.80 4.08 0.00
100.00 6.80 4.08 0.00
102.00 6.80 4.08 0.00

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 88.05 cfs @ 11.96 hrs, Volume= 4.301 af, Depth= 5.40"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
4.330 98 Paved parking & roofs
5.230 79 50-75% Grass cover, Fair, HSG C
9.560 88 Weighted Average
5.230 Pervious Area
4.330 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 5.40 0.00
2.00 0.15 0.00 0.00 106.00 6.80 5.40 0.00
4.00 0.33 0.00 0.06 108.00 6.80 5.40 0.00
6.00 0.54 0.05 0.35 110.00 6.80 5.40 0.00
8.00 0.82 0.15 0.69 112.00 6.80 5.40 0.00
10.00 1.23 0.40 1.65 114.00 6.80 5.40 0.00
12.00 4.51 3.20 73.42 116.00 6.80 5.40 0.00
14.00 5.58 4.22 2.42 118.00 6.80 5.40 0.00
16.00 5.98 4.61 1.49 120.00 6.80 5.40 0.00
18.00 6.26 4.88 1.15 122.00 6.80 5.40 0.00
20.00 6.47 5.08 0.84 124.00 6.80 5.40 0.00
22.00 6.64 5.25 0.76 126.00 6.80 5.40 0.00
24.00 6.80 5.40 0.70 128.00 6.80 5.40 0.00
26.00 6.80 5.40 0.00 130.00 6.80 5.40 0.00
28.00 6.80 5.40 0.00 132.00 6.80 5.40 0.00
30.00 6.80 5.40 0.00 134.00 6.80 5.40 0.00
32.00 6.80 5.40 0.00 136.00 6.80 5.40 0.00
34.00 6.80 5.40 0.00 138.00 6.80 5.40 0.00
36.00 6.80 5.40 0.00 140.00 6.80 5.40 0.00
38.00 6.80 5.40 0.00 142.00 6.80 5.40 0.00
40.00 6.80 5.40 0.00 144.00 6.80 5.40 0.00
42.00 6.80 5.40 0.00 146.00 6.80 5.40 0.00
44.00 6.80 5.40 0.00 148.00 6.80 5.40 0.00
46.00 6.80 5.40 0.00 150.00 6.80 5.40 0.00
48.00 6.80 5.40 0.00 152.00 6.80 5.40 0.00
50.00 6.80 5.40 0.00 154.00 6.80 5.40 0.00
52.00 6.80 5.40 0.00 156.00 6.80 5.40 0.00
54.00 6.80 5.40 0.00 158.00 6.80 5.40 0.00
56.00 6.80 5.40 0.00 160.00 6.80 5.40 0.00
58.00 6.80 5.40 0.00 162.00 6.80 5.40 0.00
60.00 6.80 5.40 0.00 164.00 6.80 5.40 0.00
62.00 6.80 5.40 0.00 166.00 6.80 5.40 0.00
64.00 6.80 5.40 0.00 168.00 6.80 5.40 0.00
66.00 6.80 5.40 0.00 170.00 6.80 5.40 0.00
68.00 6.80 5.40 0.00 172.00 6.80 5.40 0.00
70.00 6.80 5.40 0.00 174.00 6.80 5.40 0.00
72.00 6.80 5.40 0.00 176.00 6.80 5.40 0.00
74.00 6.80 5.40 0.00 178.00 6.80 5.40 0.00
76.00 6.80 5.40 0.00 180.00 6.80 5.40 0.00
78.00 6.80 5.40 0.00 182.00 6.80 5.40 0.00
80.00 6.80 5.40 0.00 184.00 6.80 5.40 0.00
82.00 6.80 5.40 0.00 186.00 6.80 5.40 0.00
84.00 6.80 5.40 0.00 188.00 6.80 5.40 0.00
86.00 6.80 5.40 0.00 190.00 6.80 5.40 0.00
88.00 6.80 5.40 0.00 192.00 6.80 5.40 0.00
90.00 6.80 5.40 0.00 194.00 6.80 5.40 0.00
92.00 6.80 5.40 0.00 196.00 6.80 5.40 0.00
94.00 6.80 5.40 0.00 198.00 6.80 5.40 0.00
96.00 6.80 5.40 0.00 200.00 6.80 5.40 0.00
98.00 6.80 5.40 0.00
100.00 6.80 5.40 0.00
102.00 6.80 5.40 0.00

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP-4)
Inflow Area = 9.560 ac, Inflow Depth = 5.40" for 50-yr Concord event
Inflow = 88.05 cfs @ 11.96 hrs, Volume= 4.301 af
Outflow = 29.12 cfs @ 12.07 hrs, Volume= 4.301 af, Atten= 67%, Lag= 6.5 min
Primary = 24.46 cfs @ 12.07 hrs, Volume= 4.257 af
Secondary= 4.67 cfs @ 12.07 hrs, Volume= 0.045 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 637.31' @ 12.07 hrs Surf.Area= 20,312 sf Storage= 93,774 cf
Plug-Flow detention time= 524.9 min calculated for 4.301 af(100% of inflow)
Center-of-Mass det. time= 524.9 min ( 1,308.0 - 783.1 )
Volume Invert Avail.Storage Storage Description
#1 631.00' 108,271 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
631.00 10,175 0 0
632.00 11,544 10,860 10,860
634.00 14,461 26,005 36,865
636.00 17,604 32,065 68,930
638.00 21,737 39,341 108,271
Device Routing Invert Outlet Devices
#1 Primary 628.30' 18.0" x 58.5' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 628.00' S= 0.0051 '/' Cc= 0.900 n= 0.013
#2 Device 1 631.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.153 0.214 0.276 0.337 0.368 0.459
#3 Device 1 633.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 636.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 637.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=24.45 cfs @ 12.07 hrs HW=637.31' (Free Discharge)
4-1=Culvert (Inlet Controls 24.45 cfs @ 13.84 fps)
2=Exfiltration (Passes < 0.46 cfs potential flow)
3=Orifice/Grate (Passes < 1.90 cfs potential flow)
4=Top of Riser (Passes < 33.06 cfs potential flow)
Secondary OutFlow Max=4.64 cfs @ 12.07 hrs HW=637.31' (Free Discharge)
L5=Spillway (Weir Controls 4.64 cfs @ 1.50 fps)

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP-4)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 631.00 0.00 0.00 0.00
5.00 0.19 486 631.05 0.01 0.01 0.00
10.00 1.65 12,067 632.10 0.16 0.16 0.00
15.00 1.92 69,473 636.03 2.15 2.15 0.00
20.00 0.84 58,467 635.39 1.73 1.73 0.00
25.00 0.00 41,909 634.34 1.28 1.28 0.00
30.00 0.00 26,496 633.25 0.40 0.40 0.00
35.00 0.00 21,921 632.91 0.21 0.21 0.00
40.00 0.00 18,329 632.62 0.19 0.19 0.00
45.00 0.00 15,040 632.35 0.17 0.17 0.00
50.00 0.00 12,038 632.10 0.16 0.16 0.00
55.00 0.00 9,367 631.87 0.13 0.13 0.00
60.00 0.00 7,242 631.68 0.10 0.10 0.00
65.00 0.00 5,583 631.53 0.08 0.08 0.00
70.00 0.00 4,295 631.41 0.06 0.06 0.00
75.00 0.00 3,298 631.32 0.05 0.05 0.00
80.00 0.00 2,528 631.24 0.04 0.04 0.00
85.00 0.00 1,936 631.19 0.03 0.03 0.00
90.00 0.00 1,482 631.14 0.02 0.02 0.00
95.00 0.00 1,133 631.11 0.02 0.02 0.00
100.00 0.00 866 631.08 0.01 0.01 0.00
105.00 0.00 662 631.06 0.01 0.01 0.00
110.00 0.00 505 631.05 0.01 0.01 0.00
115.00 0.00 386 631.04 0.01 0.01 0.00
120.00 0.00 295 631.03 0.00 0.00 0.00
125.00 0.00 225 631.02 0.00 0.00 0.00
130.00 0.00 172 631.02 0.00 0.00 0.00
135.00 0.00 131 631.01 0.00 0.00 0.00
140.00 0.00 100 631.01 0.00 0.00 0.00
145.00 0.00 77 631.01 0.00 0.00 0.00
150.00 0.00 59 631.01 0.00 0.00 0.00
155.00 0.00 45 631.00 0.00 0.00 0.00
160.00 0.00 34 631.00 0.00 0.00 0.00
165.00 0.00 26 631.00 0.00 0.00 0.00
170.00 0.00 20 631.00 0.00 0.00 0.00
175.00 0.00 15 631.00 0.00 0.00 0.00
180.00 0.00 12 631.00 0.00 0.00 0.00
185.00 0.00 9 631.00 0.00 0.00 0.00
190.00 0.00 7 631.00 0.00 0.00 0.00
195.00 0.00 5 631.00 0.00 0.00 0.00
200.00 0.00 4 631.00 0.00 0.00 0.00

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP-4)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
631.00 0.00 0.00 0.00 636.20 4.93 4.93 0.00
631.10 0.02 0.02 0.00 636.30 7.42 7.42 0.00
631.20 0.03 0.03 0.00 636.40 10.35 10.35 0.00
631.30 0.05 0.05 0.00 636.50 13.68 13.68 0.00
631.40 0.06 0.06 0.00 636.60 17.35 17.35 0.00
631.50 0.08 0.08 0.00 636.70 21.34 21.34 0.00
631.60 0.09 0.09 0.00 636.80 23.69 23.69 0.00
631.70 0.11 0.11 0.00 636.90 23.84 23.84 0.00
631.80 0.12 0.12 0.00 637.00 23.99 23.99 0.00
631.90 0.14 0.14 0.00 637.10 24.99 24.14 0.85
632.00 0.15 0.15 0.00 637.20 26.69 24.29 2.40
632.10 0.16 0.16 0.00 637.30 28.86 24.44 4.42
632.20 0.17 0.17 0.00 637.40 31.42 24.59 6.83
632.30 0.17 0.17 0.00 637.50 34.28 24.73 9.55
632.40 0.18 0.18 0.00 637.60 37.43 24.88 12.55
632.50 0.18 0.18 0.00 637.70 40.66 25.03 15.64
632.60 0.19 0.19 0.00 637.80 44.06 25.17 18.89
632.70 0.20 0.20 0.00 637.90 47.81 25.31 22.50
632.80 0.20 0.20 0.00 638.00 51.76 25.46 26.30
632.90 0.21 0.21 0.00
633.00 0.21 0.21 0.00
633.10 0.25 0.25 0.00
633.20 0.34 0.34 0.00
633.30 0.46 0.46 0.00
633.40 0.60 0.60 0.00
633.50 0.72 0.72 0.00
633.60 0.81 0.81 0.00
633.70 0.89 0.89 0.00
633.80 0.96 0.96 0.00
633.90 1.03 1.03 0.00
634.00 1.09 1.09 0.00
634.10 1.15 1.15 0.00
634.20 1.21 1.21 0.00
634.30 1.26 1.26 0.00
634.40 1.31 1.31 0.00
634.50 1.36 1.36 0.00
634.60 1.41 1.41 0.00
634.70 1.46 1.46 0.00
634.80 1.50 1.50 0.00
634.90 1.55 1.55 0.00
635.00 1.59 1.59 0.00
635.10 1.63 1.63 0.00
635.20 1.66 1.66 0.00
635.30 1.70 1.70 0.00
635.40 1.74 1.74 0.00
635.50 1.77 1.77 0.00
635.60 1.80 1.80 0.00
635.70 1.84 1.84 0.00
635.80 1.87 1.87 0.00
635.90 1.90 1.90 0.00
636.00 1.94 1.94 0.00
636.10 3.01 3.01 0.00

2020.17-BMP4 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP-4)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
631.00 10,175 0 636.20 18,017 72,492
631.10 10,312 1,024 636.30 18,224 74,304
631.20 10,449 2,062 636.40 18,431 76,136
631.30 10,586 3,114 636.50 18,637 77,990
631.40 10,723 4,180 636.60 18,844 79,864
631.50 10,860 5,259 636.70 19,051 81,759
631.60 10,996 6,351 636.80 19,257 83,674
631.70 11,133 7,458 636.90 19,464 85,610
631.80 11,270 8,578 637.00 19,671 87,567
631.90 11,407 9,712 637.10 19,877 89,544
632.00 11,544 10,860 637.20 20,084 91,542
632.10 11,690 12,021 637.30 20,290 93,561
632.20 11,836 13,197 637.40 20,497 95,600
632.30 11,982 14,388 637.50 20,704 97,660
632.40 12,127 15,594 637.60 20,910 99,741
632.50 12,273 16,814 637.70 21,117 101,842
632.60 12,419 18,048 637.80 21,324 103,964
632.70 12,565 19,298 637.90 21,530 106,107
632.80 12,711 20,561 638.00 21,737 108,271
632.90 12,857 21,840
633.00 13,003 23,133
633.10 13,148 24,440
633.20 13,294 25,762
633.30 13,440 27,099
633.40 13,586 28,450
633.50 13,732 29,816
633.60 13,878 31,197
633.70 14,023 32,592
633.80 14,169 34,001
633.90 14,315 35,426
634.00 14,461 36,865
634.10 14,618 38,318
634.20 14,775 39,788
634.30 14,932 41,274
634.40 15,090 42,775
634.50 15,247 44,291
634.60 15,404 45,824
634.70 15,561 47,372
634.80 15,718 48,936
634.90 15,875 50,516
635.00 16,033 52,111
635.10 16,190 53,722
635.20 16,347 55,349
635.30 16,504 56,992
635.40 16,661 58,650
635.50 16,818 60,324
635.60 16,975 62,014
635.70 17,133 63,719
635.80 17,290 65,440
635.90 17,447 67,177
636.00 17,604 68,930
636.10 17,811 70,700

SAND FILTER-5
•
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Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 5
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 8.07 ac
Impervious area to filter forebay= 3.14 ac.
Impervious percentage= 38.96%
Rv=0.05+0.9(la) = 0.40060268
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 11735 cf (used to size Af)
WQV= 0.2694 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
613 7472 0 0
614 8936 8204 8204
615 10664 9800 18004
616 12392 11528 29532
617 14515 13453.5 42985.5
618 16637 15576 58561.5
619 19188 17912.5 76474
620 21739 20463.5 96937.5
Calculate Depth for WQ Volume:
614 8204
614.33 11735
616 29532
Elevation of WQ Volume= 614.33
3. Discount WQv:
0.75 x WQv 8801.47 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 73.0
Cn Post= 86.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 5.41 17.65 23.26 28.41
Post. Dev. 23.44 50.94 62.26 72.29
Routed 0.90 16.05 28.38 29.01
Peak Stage 615.81 617.58 618.02 618.52
Disch.Time 105 hours 1.5' Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
1467 SA(ft2) DV"12
2 FS SA = FS" K"T
8801 DV(FT3) where: SA =required minimum surface area of infiltration system(fK)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(10)
K =hydraulic conductivity of soil(in/hr)
72 T(hours) T =maximum dewatering time(72 hours)
6.Sediment Sand Sizing
8801 Design Volume(ft3)
4401 Sediment Chamber(ft3)
4401 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 244.4853 cf/hour 0.068 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
92 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 1472 holes
50%of perforations= 736 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 6.1088 cfs which is 90.0 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
Dimensions of Riser
7 Height of Riser,ft. 2 ft L
6 Area of Riser,s.f. 3 ft W
42 Volume of Riser,c.f. 0.5 ft
2620.8 Weight of Water©62.4 pcf
2882.88 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
1.29 Volume of Concrete Req'd in c.y.
34.90 Volume of Concrete Req'd in c.f.
42 Volume of Concrete in Structure(cf)
-7.10 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
1 ft thick
1.9 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 1467 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 9779.413 0.113
2 13691.18 0.158
3 17602.94 0.204
4 21514.71 0.249
5 25426.47 0.294
6 29338.24 0.340
7 33250 0.385
8 37161.77 0.430
9 41073.53 0.475
10 44985.3 0.521

•
(Predeveloped)
e > 3P
(Post Developed) (BMP5)
(Subcat Reach 'On. MI Drainage Diagram for 2020.17-BMP5
Prepared by{enter your company name here} 1/23/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP5
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
8.050 73 Woods, Fair, HSG C (1S)
4.930 79 50-75% Grass cover, Fair, HSG C (2S)
3.140 98 Paved parking & roofs (2S)
16.120

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.050 ac Runoff Depth=0.80"
Flow Length=487' Tc=26.5 min CN=73 Runoff=5.41 cfs 0.534 af
Subcatchment 2S: (Post Developed) Runoff Area=8.070 ac Runoff Depth=1.58"
Tc=5.0 min CN=86 Runoff=23.44 cfs 1.061 af
Pond 3P: (BMP5) Peak Elev=615.81' Storage=27,193 cf Inflow=23.44 cfs 1.061 af
Primary=0.90 cfs 1.061 af Secondary=0.00 cfs 0.000 af Outflow=0.90 cfs 1.061 af
Total Runoff Area = 16.120 ac Runoff Volume = 1.595 of Average Runoff Depth = 1.19"
80.52% Pervious Area= 12.980 ac 19.48% Impervious Area = 3.140 ac

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 5.41 cfs @ 12.22 hrs, Volume= 0.534 af, Depth= 0.80"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description _
8.050 73 Woods, Fair, HSG C _
8.050 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) _ (cfs)
22.5 100 0.0637 0.07 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.0 387 0.1050 1.62 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
26.5 487 Total

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.80 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.80 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.80 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.80 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.80 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.80 0.00
12.00 1.92 0.29 1.95 116.00 2.90 0.80 0.00
14.00 2.38 0.50 0.55 118.00 2.90 0.80 0.00
16.00 2.55 0.60 0.33 120.00 2.90 0.80 0.00
18.00 2.67 0.66 0.25 122.00 2.90 0.80 0.00
20.00 2.76 0.71 0.19 124.00 2.90 0.80 0.00
22.00 2.83 0.76 0.17 126.00 2.90 0.80 0.00
24.00 2.90 0.80 0.16 128.00 2.90 0.80 0.00
26.00 2.90 0.80 0.00 130.00 2.90 0.80 0.00
28.00 2.90 0.80 0.00 132.00 2.90 0.80 0.00
30.00 2.90 0.80 0.00 134.00 2.90 0.80 0.00
32.00 2.90 0.80 0.00 136.00 2.90 0.80 0.00
34.00 2.90 0.80 0.00 138.00 2.90 0.80 0.00
36.00 2.90 0.80 0.00 140.00 2.90 0.80 0.00
38.00 2.90 0.80 0.00 142.00 2.90 0.80 0.00
40.00 2.90 0.80 0.00 144.00 2.90 0.80 0.00
42.00 2.90 0.80 0.00 146.00 2.90 0.80 0.00
44.00 2.90 0.80 0.00 148.00 2.90 0.80 0.00
46.00 2.90 0.80 0.00 150.00 2.90 0.80 0.00
48.00 2.90 0.80 0.00 152.00 2.90 0.80 0.00
50.00 2.90 0.80 0.00 154.00 2.90 0.80 0.00
52.00 2.90 0.80 0.00 156.00 2.90 0.80 0.00
54.00 2.90 0.80 0.00 158.00 2.90 0.80 0.00
56.00 2.90 0.80 0.00 160.00 2.90 0.80 0.00
58.00 2.90 0.80 0.00 162.00 2.90 0.80 0.00
60.00 2.90 0.80 0.00 164.00 2.90 0.80 0.00
62.00 2.90 0.80 0.00 166.00 2.90 0.80 0.00
64.00 2.90 0.80 0.00 168.00 2.90 0.80 0.00
66.00 2.90 0.80 0.00 170.00 2.90 0.80 0.00
68.00 2.90 0.80 0.00 172.00 2.90 0.80 0.00
70.00 2.90 0.80 0.00 174.00 2.90 0.80 0.00
72.00 2.90 0.80 0.00 176.00 2.90 0.80 0.00
74.00 2.90 0.80 0.00 178.00 2.90 0.80 0.00
76.00 2.90 0.80 0.00 180.00 2.90 0.80 0.00
78.00 2.90 0.80 0.00 182.00 2.90 0.80 0.00
80.00 2.90 0.80 0.00 184.00 2.90 0.80 0.00
82.00 2.90 0.80 0.00 186.00 2.90 0.80 0.00
84.00 2.90 0.80 0.00 188.00 2.90 0.80 0.00
86.00 2.90 0.80 0.00 190.00 2.90 0.80 0.00
88.00 2.90 0.80 0.00 192.00 2.90 0.80 0.00
90.00 2.90 0.80 0.00 194.00 2.90 0.80 0.00
92.00 2.90 0.80 0.00 196.00 2.90 0.80 0.00
94.00 2.90 0.80 0.00 198.00 2.90 0.80 0.00
96.00 2.90 0.80 0.00 200.00 2.90 0.80 0.00
98.00 2.90 0.80 0.00
100.00 2.90 0.80 0.00
102.00 2.90 0.80 0.00

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 23.44 cfs @ 11.96 hrs, Volume= 1.061 af, Depth= 1.58"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
3.140 98 Paved parking & roofs
4.930 79 50-75% Grass cover, Fair, HSG C
8.070 86 Weighted Average
4.930 Pervious Area
3.140 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.58 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.58 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.58 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.58 0.00
8.00 0.35 0.00 0.01 112.00 2.90 1.58 0.00
10.00 0.52 0.02 0.18 114.00 2.90 1.58 0.00
12.00 1.92 0.79 20.11 116.00 2.90 1.58 0.00
14.00 2.38 1.14 0.73 118.00 2.90 1.58 0.00
16.00 2.55 1.29 0.46 120.00 2.90 1.58 0.00
18.00 2.67 1.38 0.36 122.00 2.90 1.58 0.00
20.00 2.76 1.46 0.26 124.00 2.90 1.58 0.00
22.00 2.83 1.52 0.24 126.00 2.90 1.58 0.00
24.00 2.90 1.58 0.22 128.00 2.90 1.58 0.00
26.00 2.90 1.58 0.00 130.00 2.90 1.58 0.00
28.00 2.90 1.58 0.00 132.00 2.90 1.58 0.00
30.00 2.90 1.58 0.00 134.00 2.90 1.58 0.00
32.00 2.90 1.58 0.00 136.00 2.90 1.58 0.00
34.00 2.90 1.58 0.00 138.00 2.90 1.58 0.00
36.00 2.90 1.58 0.00 140.00 2.90 1.58 0.00
38.00 2.90 1.58 0.00 142.00 2.90 1.58 0.00
40.00 2.90 1.58 0.00 144.00 2.90 1.58 0.00
42.00 2.90 1.58 0.00 146.00 2.90 1.58 0.00
44.00 2.90 1.58 0.00 148.00 2.90 1.58 0.00
46.00 2.90 1.58 0.00 150.00 2.90 1.58 0.00
48.00 2.90 1.58 0.00 152.00 2.90 1.58 0.00
50.00 2.90 1.58 0.00 154.00 2.90 1.58 0.00
52.00 2.90 1.58 0.00 156.00 2.90 1.58 0.00
54.00 2.90 1.58 0.00 158.00 2.90 1.58 0.00
56.00 2.90 1.58 0.00 160.00 2.90 1.58 0.00
58.00 2.90 1.58 0.00 162.00 2.90 1.58 0.00
60.00 2.90 1.58 0.00 164.00 2.90 1.58 0.00
62.00 2.90 1.58 0.00 166.00 2.90 1.58 0.00
64.00 2.90 1.58 0.00 168.00 2.90 1.58 0.00
66.00 2.90 1.58 0.00 170.00 2.90 1.58 0.00
68.00 2.90 1.58 0.00 172.00 2.90 1.58 0.00
70.00 2.90 1.58 0.00 174.00 2.90 1.58 0.00
72.00 2.90 1.58 0.00 176.00 2.90 1.58 0.00
74.00 2.90 1.58 0.00 178.00 2.90 1.58 0.00
76.00 2.90 1.58 0.00 180.00 2.90 1.58 0.00
78.00 2.90 1.58 0.00 182.00 2.90 1.58 0.00
80.00 2.90 1.58 0.00 184.00 2.90 1.58 0.00
82.00 2.90 1.58 0.00 186.00 2.90 1.58 0.00
84.00 2.90 1.58 0.00 188.00 2.90 1.58 0.00
86.00 2.90 1.58 0.00 190.00 2.90 1.58 0.00
88.00 2.90 1.58 0.00 192.00 2.90 1.58 0.00
90.00 2.90 1.58 0.00 194.00 2.90 1.58 0.00
92.00 2.90 1.58 0.00 196.00 2.90 1.58 0.00
94.00 2.90 1.58 0.00 198.00 2.90 1.58 0.00
96.00 2.90 1.58 0.00 200.00 2.90 1.58 0.00
98.00 2.90 1.58 0.00
100.00 2.90 1.58 0.00
102.00 2.90 1.58 0.00

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP5)
Inflow Area = 8.070 ac, Inflow Depth = 1.58" for 1-yr Concord event
Inflow = 23.44 cfs @ 11.96 hrs, Volume= 1.061 af
Outflow = 0.90 cfs @ 13.54 hrs, Volume= 1.061 af, Atten= 96%, Lag= 95.0 min
Primary = 0.90 cfs @ 13.54 hrs, Volume= 1.061 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 615.81' @ 13.54 hrs Surf.Area= 12,061 sf Storage= 27,193 cf
Plug-Flow detention time= 989.1 min calculated for 1.061 of(100% of inflow)
Center-of-Mass det. time= 989.6 min ( 1,812.4 - 822.8 )
Volume Invert Avail.Storage Storage Description
#1 613.00' 96,937 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
613.00 7,472 0 0
614.00 8,936 8,204 8,204
616.00 12,392 21,328 29,532
618.00 16,637 29,029 58,561
620.00 21,739 38,376 96,937
Device Routing Invert Outlet Devices
#1 Primary 604.50' 18.0" x 89.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 604.00' S= 0.0056 '/' Cc= 0.900 n= 0.013
#2 Device 1 613.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.113 0.158 0.204 0.249 0.294 0.340
#3 Device 1 615.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 617.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 618.50' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=0.90 cfs @ 13.54 hrs HW=615.81' (Free Discharge)
4-1=Culvert (Passes 0.90 cfs of 25.75 cfs potential flow)
2=Exfiltration (Custom Controls 0.20 cfs)
3=Orifice/Grate (Orifice Controls 0.71 cfs @ 3.60 fps)
4=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=613.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP5)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 613.00 0.00 0.00 0.00
5.00 0.00 0 613.00 0.00 0.00 0.00
10.00 0.18 564 613.07 0.01 0.01 0.00
15.00 0.59 26,257 615.73 0.85 0.85 0.00
20.00 0.26 21,565 615.33 0.44 0.44 0.00
25.00 0.00 19,331 615.12 0.21 0.21 0.00
30.00 0.00 16,383 614.85 0.15 0.15 0.00
35.00 0.00 13,769 614.59 0.14 0.14 0.00
40.00 0.00 11,358 614.34 0.13 0.13 0.00
45.00 0.00 9,144 614.10 0.12 0.12 0.00
50.00 0.00 7,158 613.88 0.10 0.10 0.00
55.00 0.00 5,560 613.70 0.08 0.08 0.00
60.00 0.00 4,301 613.55 0.06 0.06 0.00
65.00 0.00 3,317 613.43 0.05 0.05 0.00
70.00 0.00 2,551 613.33 0.04 0.04 0.00
75.00 0.00 1,958 613.26 0.03 0.03 0.00
80.00 0.00 1,500 613.20 0.02 0.02 0.00
85.00 0.00 1,148 613.15 0.02 0.02 0.00
90.00 0.00 878 613.12 0.01 0.01 0.00
95.00 0.00 671 613.09 0.01 0.01 0.00
100.00 0.00 512 613.07 0.01 0.01 0.00
105.00 0.00 391 613.05 0.01 0.01 0.00
110.00 0.00 298 613.04 0.00 0.00 0.00
115.00 0.00 227 613.03 0.00 0.00 0.00
120.00 0.00 174 613.02 0.00 0.00 0.00
125.00 0.00 132 613.02 0.00 0.00 0.00
130.00 0.00 101 613.01 0.00 0.00 0.00
135.00 0.00 77 613.01 0.00 0.00 0.00
140.00 0.00 59 613.01 0.00 0.00 0.00
145.00 0.00 45 613.01 0.00 0.00 0.00
150.00 0.00 34 613.00 0.00 0.00 0.00
155.00 0.00 26 613.00 0.00 0.00 0.00
160.00 0.00 20 613.00 0.00 0.00 0.00
165.00 0.00 15 613.00 0.00 0.00 0.00
170.00 0.00 12 613.00 0.00 0.00 0.00
175.00 0.00 9 613.00 0.00 0.00 0.00
180.00 0.00 7 613.00 0.00 0.00 0.00
185.00 0.00 5 613.00 0.00 0.00 0.00
190.00 0.00 4 613.00 0.00 0.00 0.00
195.00 0.00 3 613.00 0.00 0.00 0.00
200.00 0.00 2 613.00 0.00 0.00 0.00

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP5)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
613.00 0.00 0.00 0.00 618.20 28.58 28.58 0.00
613.10 0.01 0.01 0.00 618.30 28.69 28.69 0.00
613.20 0.02 0.02 0.00 618.40 28.80 28.80 0.00
613.30 0.03 0.03 0.00 618.50 28.91 28.91 0.00
613.40 0.05 0.05 0.00 618.60 29.87 29.02 0.85
613.50 0.06 0.06 0.00 618.70 31.53 29.13 2.40
613.60 0.07 0.07 0.00 618.80 33.66 29.24 4.42
613.70 0.08 0.08 0.00 618.90 36.18 29.35 6.83
613.80 0.09 0.09 0.00 619.00 39.01 29.46 9.55
613.90 0.10 0.10 0.00 619.10 42.12 29.57 12.55
614.00 0.11 0.11 0.00 619.20 45.32 29.68 15.64
614.10 0.12 0.12 0.00 619.30 48.68 29.79 18.89
614.20 0.12 0.12 0.00 619.40 52.39 29.90 22.50
614.30 0.13 0.13 0.00 619.50 56.30 30.00 26.30
614.40 0.13 0.13 0.00 619.60 60.51 30.11 30.40
614.50 0.14 0.14 0.00 619.70 64.92 30.22 34.70
614.60 0.14 0.14 0.00 619.80 69.45 30.32 39.13
614.70 0.14 0.14 0.00 619.90 74.16 30.43 43.73
614.80 0.15 0.15 0.00 620.00 78.94 30.53 48.41
614.90 0.15 0.15 0.00
615.00 0.16 0.16 0.00
615.10 0.19 0.19 0.00
615.20 0.28 0.28 0.00
615.30 0.40 0.40 0.00
615.40 0.54 0.54 0.00
615.50 0.65 0.65 0.00
615.60 0.74 0.74 0.00
615.70 0.82 0.82 0.00
615.80 0.90 0.90 0.00
615.90 0.96 0.96 0.00
616.00 1.02 1.02 0.00
616.10 1.08 1.08 0.00
616.20 1.13 1.13 0.00
616.30 1.19 1.19 0.00
616.40 1.24 1.24 0.00
616.50 1.28 1.28 0.00
616.60 1.33 1.33 0.00
616.70 1.37 1.37 0.00
616.80 1.42 1.42 0.00
616.90 1.46 1.46 0.00
617.00 1.50 1.50 0.00
617.10 2.57 2.57 0.00
617.20 4.50 4.50 0.00
617.30 6.99 6.99 0.00
617.40 9.93 9.93 0.00
617.50 13.25 13.25 0.00
617.60 16.92 16.92 0.00
617.70 20.91 20.91 0.00
617.80 25.19 25.19 0.00
617.90 28.24 28.24 0.00
618.00 28.35 28.35 0.00
618.10 28.46 28.46 0.00

2020.17-BMP5 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP5)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
613.00 7,472 0 618.20 17,147 61,939
613.10 7,618 755 618.30 17,402 63,667
613.20 7,765 1,524 618.40 17,657 65,420
613.30 7,911 2,307 618.50 17,913 67,198
613.40 8,058 3,106 618.60 18,168 69,002
613.50 8,204 3,919 618.70 18,423 70,832
613.60 8,350 4,747 618.80 18,678 72,687
613.70 8,497 5,589 618.90 18,933 74,567
613.80 8,643 6,446 619.00 19,188 76,474
613.90 8,790 7,318 619.10 19,443 78,405
614.00 8,936 8,204 619.20 19,698 80,362
614.10 9,109 9,106 619.30 19,953 82,345
614.20 9,282 10,026 619.40 20,208 84,353
614.30 9,454 10,963 619.50 20,464 86,386
614.40 9,627 11,917 619.60 20,719 88,445
614.50 9,800 12,888 619.70 20,974 90,530
614.60 9,973 13,877 619.80 21,229 92,640
614.70 10,146 14,883 619.90 21,484 94,776
614.80 10,318 15,906 620.00 21,739 96,937
614.90 10,491 16,946
615.00 10,664 18,004
615.10 10,837 19,079
615.20 11,010 20,171
615.30 11,182 21,281
615.40 11,355 22,408
615.50 11,528 23,552
615.60 11,701 24,713
615.70 11,874 25,892
615.80 12,046 27,088
615.90 12,219 28,301
616.00 12,392 29,532
616.10 12,604 30,782
616.20 12,817 32,053
616.30 13,029 33,345
616.40 13,241 34,659
616.50 13,453 35,993
616.60 13,666 37,349
616.70 13,878 38,726
616.80 14,090 40,125
616.90 14,302 41,544
617.00 14,515 42,985
617.10 14,727 44,447
617.20 14,939 45,931
617.30 15,151 47,435
617.40 15,363 48,961
617.50 15,576 50,508
617.60 15,788 52,076
617.70 16,000 53,665
617.80 16,212 55,276
617.90 16,425 56,908
618.00 16,637 58,561
618.10 16,892 60,237

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.050 ac Runoff Depth=2.36"
Flow Length=487' Tc=26.5 min CN=73 Runoff=17.65 cfs 1.583 af
Subcatchment 2S: (Post Developed) Runoff Area=8.070 ac Runoff Depth=3.56"
Tc=5.0 min CN=86 Runoff=50.94 cfs 2.394 af
Pond 3P: (BMP5) Peak Elev=617.58' Storage=51,706 cf Inflow=50.94 cfs 2.394 af
Primary=16.05 cfs 2.394 af Secondary=0.00 cfs 0.000 af Outflow=16.05 cfs 2.394 af
Total Runoff Area = 16.120 ac Runoff Volume = 3.977 af Average Runoff Depth = 2.96"
80.52% Pervious Area = 12.980 ac 19.48% Impervious Area = 3.140 ac

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 17.65 cfs @ 12.22 hrs, Volume= 1.583 af, Depth= 2.36"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description _
8.050 73 Woods, Fair, HSG C _
8.050 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) _ (cfs)
22.5 100 0.0637 0.07 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.0 387 0.1050 1.62 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
26.5 487 Total

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 2.36 0.00
2.00 0.11 0.00 0.00 106.00 5.10 2.36 0.00
4.00 0.24 0.00 0.00 108.00 5.10 2.36 0.00
6.00 0.41 0.00 0.00 110.00 5.10 2.36 0.00
8.00 0.61 0.00 0.00 112.00 5.10 2.36 0.00
10.00 0.92 0.01 0.08 114.00 5.10 2.36 0.00
12.00 3.38 1.10 8.51 116.00 5.10 2.36 0.00
14.00 4.18 1.66 1.37 118.00 5.10 2.36 0.00
16.00 4.49 1.89 0.80 120.00 5.10 2.36 0.00
18.00 4.70 2.05 0.60 122.00 5.10 2.36 0.00
20.00 4.86 2.17 0.45 124.00 5.10 2.36 0.00
22.00 4.98 2.27 0.40 126.00 5.10 2.36 0.00
24.00 5.10 2.36 0.37 128.00 5.10 2.36 0.00
26.00 5.10 2.36 0.00 130.00 5.10 2.36 0.00
28.00 5.10 2.36 0.00 132.00 5.10 2.36 0.00
30.00 5.10 2.36 0.00 134.00 5.10 2.36 0.00
32.00 5.10 2.36 0.00 136.00 5.10 2.36 0.00
34.00 5.10 2.36 0.00 138.00 5.10 2.36 0.00
36.00 5.10 2.36 0.00 140.00 5.10 2.36 0.00
38.00 5.10 2.36 0.00 142.00 5.10 2.36 0.00
40.00 5.10 2.36 0.00 144.00 5.10 2.36 0.00
42.00 5.10 2.36 0.00 146.00 5.10 2.36 0.00
44.00 5.10 2.36 0.00 148.00 5.10 2.36 0.00
46.00 5.10 2.36 0.00 150.00 5.10 2.36 0.00
48.00 5.10 2.36 0.00 152.00 5.10 2.36 0.00
50.00 5.10 2.36 0.00 154.00 5.10 2.36 0.00
52.00 5.10 2.36 0.00 156.00 5.10 2.36 0.00
54.00 5.10 2.36 0.00 158.00 5.10 2.36 0.00
56.00 5.10 2.36 0.00 160.00 5.10 2.36 0.00
58.00 5.10 2.36 0.00 162.00 5.10 2.36 0.00
60.00 5.10 2.36 0.00 164.00 5.10 2.36 0.00
62.00 5.10 2.36 0.00 166.00 5.10 2.36 0.00
64.00 5.10 2.36 0.00 168.00 5.10 2.36 0.00
66.00 5.10 2.36 0.00 170.00 5.10 2.36 0.00
68.00 5.10 2.36 0.00 172.00 5.10 2.36 0.00
70.00 5.10 2.36 0.00 174.00 5.10 2.36 0.00
72.00 5.10 2.36 0.00 176.00 5.10 2.36 0.00
74.00 5.10 2.36 0.00 178.00 5.10 2.36 0.00
76.00 5.10 2.36 0.00 180.00 5.10 2.36 0.00
78.00 5.10 2.36 0.00 182.00 5.10 2.36 0.00
80.00 5.10 2.36 0.00 184.00 5.10 2.36 0.00
82.00 5.10 2.36 0.00 186.00 5.10 2.36 0.00
84.00 5.10 2.36 0.00 188.00 5.10 2.36 0.00
86.00 5.10 2.36 0.00 190.00 5.10 2.36 0.00
88.00 5.10 2.36 0.00 192.00 5.10 2.36 0.00
90.00 5.10 2.36 0.00 194.00 5.10 2.36 0.00
92.00 5.10 2.36 0.00 196.00 5.10 2.36 0.00
94.00 5.10 2.36 0.00 198.00 5.10 2.36 0.00
96.00 5.10 2.36 0.00 200.00 5.10 2.36 0.00
98.00 5.10 2.36 0.00
100.00 5.10 2.36 0.00
102.00 5.10 2.36 0.00

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 50.94 cfs @ 11.96 hrs, Volume= 2.394 af, Depth= 3.56"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
3.140 98 Paved parking & roofs
4.930 79 50-75% Grass cover, Fair, HSG C
8.070 86 Weighted Average
4.930 Pervious Area
3.140 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.56 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.56 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.56 0.00
6.00 0.41 0.00 0.06 110.00 5.10 3.56 0.00
8.00 0.61 0.04 0.25 112.00 5.10 3.56 0.00
10.00 0.92 0.16 0.74 114.00 5.10 3.56 0.00
12.00 3.38 1.99 42.88 116.00 5.10 3.56 0.00
14.00 4.18 2.71 1.46 118.00 5.10 3.56 0.00
16.00 4.49 2.99 0.90 120.00 5.10 3.56 0.00
18.00 4.70 3.19 0.70 122.00 5.10 3.56 0.00
20.00 4.86 3.33 0.51 124.00 5.10 3.56 0.00
22.00 4.98 3.45 0.47 126.00 5.10 3.56 0.00
24.00 5.10 3.56 0.43 128.00 5.10 3.56 0.00
26.00 5.10 3.56 0.00 130.00 5.10 3.56 0.00
28.00 5.10 3.56 0.00 132.00 5.10 3.56 0.00
30.00 5.10 3.56 0.00 134.00 5.10 3.56 0.00
32.00 5.10 3.56 0.00 136.00 5.10 3.56 0.00
34.00 5.10 3.56 0.00 138.00 5.10 3.56 0.00
36.00 5.10 3.56 0.00 140.00 5.10 3.56 0.00
38.00 5.10 3.56 0.00 142.00 5.10 3.56 0.00
40.00 5.10 3.56 0.00 144.00 5.10 3.56 0.00
42.00 5.10 3.56 0.00 146.00 5.10 3.56 0.00
44.00 5.10 3.56 0.00 148.00 5.10 3.56 0.00
46.00 5.10 3.56 0.00 150.00 5.10 3.56 0.00
48.00 5.10 3.56 0.00 152.00 5.10 3.56 0.00
50.00 5.10 3.56 0.00 154.00 5.10 3.56 0.00
52.00 5.10 3.56 0.00 156.00 5.10 3.56 0.00
54.00 5.10 3.56 0.00 158.00 5.10 3.56 0.00
56.00 5.10 3.56 0.00 160.00 5.10 3.56 0.00
58.00 5.10 3.56 0.00 162.00 5.10 3.56 0.00
60.00 5.10 3.56 0.00 164.00 5.10 3.56 0.00
62.00 5.10 3.56 0.00 166.00 5.10 3.56 0.00
64.00 5.10 3.56 0.00 168.00 5.10 3.56 0.00
66.00 5.10 3.56 0.00 170.00 5.10 3.56 0.00
68.00 5.10 3.56 0.00 172.00 5.10 3.56 0.00
70.00 5.10 3.56 0.00 174.00 5.10 3.56 0.00
72.00 5.10 3.56 0.00 176.00 5.10 3.56 0.00
74.00 5.10 3.56 0.00 178.00 5.10 3.56 0.00
76.00 5.10 3.56 0.00 180.00 5.10 3.56 0.00
78.00 5.10 3.56 0.00 182.00 5.10 3.56 0.00
80.00 5.10 3.56 0.00 184.00 5.10 3.56 0.00
82.00 5.10 3.56 0.00 186.00 5.10 3.56 0.00
84.00 5.10 3.56 0.00 188.00 5.10 3.56 0.00
86.00 5.10 3.56 0.00 190.00 5.10 3.56 0.00
88.00 5.10 3.56 0.00 192.00 5.10 3.56 0.00
90.00 5.10 3.56 0.00 194.00 5.10 3.56 0.00
92.00 5.10 3.56 0.00 196.00 5.10 3.56 0.00
94.00 5.10 3.56 0.00 198.00 5.10 3.56 0.00
96.00 5.10 3.56 0.00 200.00 5.10 3.56 0.00
98.00 5.10 3.56 0.00
100.00 5.10 3.56 0.00
102.00 5.10 3.56 0.00

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP5)
Inflow Area = 8.070 ac, Inflow Depth = 3.56" for 10-yr Concord event
Inflow = 50.94 cfs @ 11.96 hrs, Volume= 2.394 af
Outflow = 16.05 cfs @ 12.07 hrs, Volume= 2.394 af, Atten= 68%, Lag= 6.7 min
Primary = 16.05 cfs @ 12.07 hrs, Volume= 2.394 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 617.58' @ 12.07 hrs Surf.Area= 15,738 sf Storage= 51,706 cf
Plug-Flow detention time= 575.2 min calculated for 2.394 af(100% of inflow)
Center-of-Mass det. time= 575.7 min ( 1,375.3 - 799.7 )
Volume Invert Avail.Storage Storage Description
#1 613.00' 96,937 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
613.00 7,472 0 0
614.00 8,936 8,204 8,204
616.00 12,392 21,328 29,532
618.00 16,637 29,029 58,561
620.00 21,739 38,376 96,937
Device Routing Invert Outlet Devices
#1 Primary 604.50' 18.0" x 89.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 604.00' S= 0.0056 '/' Cc= 0.900 n= 0.013
#2 Device 1 613.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.113 0.158 0.204 0.249 0.294 0.340
#3 Device 1 615.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 617.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 618.50' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=16.03 cfs @ 12.07 hrs HW=617.58' (Free Discharge)
4-1=Culvert (Passes 16.03 cfs of 27.87 cfs potential flow)
2=Exfiltration (Custom Controls 0.27 cfs)
3=Orifice/Grate (Orifice Controls 1.44 cfs @ 7.34 fps)
4=Top of Riser (Weir Controls 14.31 cfs @ 2.48 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=613.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP5)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 613.00 0.00 0.00 0.00
5.00 0.00 0 613.00 0.00 0.00 0.00
10.00 0.74 4,181 613.53 0.06 0.06 0.00
15.00 1.16 42,508 616.97 1.49 1.49 0.00
20.00 0.51 32,241 616.21 1.14 1.14 0.00
25.00 0.00 22,821 615.44 0.59 0.59 0.00
30.00 0.00 17,917 614.99 0.16 0.16 0.00
35.00 0.00 15,186 614.73 0.15 0.15 0.00
40.00 0.00 12,664 614.48 0.13 0.13 0.00
45.00 0.00 10,343 614.23 0.12 0.12 0.00
50.00 0.00 8,214 614.00 0.11 0.11 0.00
55.00 0.00 6,395 613.79 0.09 0.09 0.00
60.00 0.00 4,958 613.63 0.07 0.07 0.00
65.00 0.00 3,830 613.49 0.06 0.06 0.00
70.00 0.00 2,950 613.38 0.04 0.04 0.00
75.00 0.00 2,267 613.29 0.03 0.03 0.00
80.00 0.00 1,738 613.23 0.03 0.03 0.00
85.00 0.00 1,331 613.18 0.02 0.02 0.00
90.00 0.00 1,018 613.13 0.02 0.02 0.00
95.00 0.00 778 613.10 0.01 0.01 0.00
100.00 0.00 594 613.08 0.01 0.01 0.00
105.00 0.00 454 613.06 0.01 0.01 0.00
110.00 0.00 346 613.05 0.01 0.01 0.00
115.00 0.00 264 613.04 0.00 0.00 0.00
120.00 0.00 202 613.03 0.00 0.00 0.00
125.00 0.00 154 613.02 0.00 0.00 0.00
130.00 0.00 117 613.02 0.00 0.00 0.00
135.00 0.00 90 613.01 0.00 0.00 0.00
140.00 0.00 68 613.01 0.00 0.00 0.00
145.00 0.00 52 613.01 0.00 0.00 0.00
150.00 0.00 40 613.01 0.00 0.00 0.00
155.00 0.00 30 613.00 0.00 0.00 0.00
160.00 0.00 23 613.00 0.00 0.00 0.00
165.00 0.00 18 613.00 0.00 0.00 0.00
170.00 0.00 13 613.00 0.00 0.00 0.00
175.00 0.00 10 613.00 0.00 0.00 0.00
180.00 0.00 8 613.00 0.00 0.00 0.00
185.00 0.00 6 613.00 0.00 0.00 0.00
190.00 0.00 5 613.00 0.00 0.00 0.00
195.00 0.00 3 613.00 0.00 0.00 0.00
200.00 0.00 3 613.00 0.00 0.00 0.00

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP5)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
613.00 0.00 0.00 0.00 618.20 28.58 28.58 0.00
613.10 0.01 0.01 0.00 618.30 28.69 28.69 0.00
613.20 0.02 0.02 0.00 618.40 28.80 28.80 0.00
613.30 0.03 0.03 0.00 618.50 28.91 28.91 0.00
613.40 0.05 0.05 0.00 618.60 29.87 29.02 0.85
613.50 0.06 0.06 0.00 618.70 31.53 29.13 2.40
613.60 0.07 0.07 0.00 618.80 33.66 29.24 4.42
613.70 0.08 0.08 0.00 618.90 36.18 29.35 6.83
613.80 0.09 0.09 0.00 619.00 39.01 29.46 9.55
613.90 0.10 0.10 0.00 619.10 42.12 29.57 12.55
614.00 0.11 0.11 0.00 619.20 45.32 29.68 15.64
614.10 0.12 0.12 0.00 619.30 48.68 29.79 18.89
614.20 0.12 0.12 0.00 619.40 52.39 29.90 22.50
614.30 0.13 0.13 0.00 619.50 56.30 30.00 26.30
614.40 0.13 0.13 0.00 619.60 60.51 30.11 30.40
614.50 0.14 0.14 0.00 619.70 64.92 30.22 34.70
614.60 0.14 0.14 0.00 619.80 69.45 30.32 39.13
614.70 0.14 0.14 0.00 619.90 74.16 30.43 43.73
614.80 0.15 0.15 0.00 620.00 78.94 30.53 48.41
614.90 0.15 0.15 0.00
615.00 0.16 0.16 0.00
615.10 0.19 0.19 0.00
615.20 0.28 0.28 0.00
615.30 0.40 0.40 0.00
615.40 0.54 0.54 0.00
615.50 0.65 0.65 0.00
615.60 0.74 0.74 0.00
615.70 0.82 0.82 0.00
615.80 0.90 0.90 0.00
615.90 0.96 0.96 0.00
616.00 1.02 1.02 0.00
616.10 1.08 1.08 0.00
616.20 1.13 1.13 0.00
616.30 1.19 1.19 0.00
616.40 1.24 1.24 0.00
616.50 1.28 1.28 0.00
616.60 1.33 1.33 0.00
616.70 1.37 1.37 0.00
616.80 1.42 1.42 0.00
616.90 1.46 1.46 0.00
617.00 1.50 1.50 0.00
617.10 2.57 2.57 0.00
617.20 4.50 4.50 0.00
617.30 6.99 6.99 0.00
617.40 9.93 9.93 0.00
617.50 13.25 13.25 0.00
617.60 16.92 16.92 0.00
617.70 20.91 20.91 0.00
617.80 25.19 25.19 0.00
617.90 28.24 28.24 0.00
618.00 28.35 28.35 0.00
618.10 28.46 28.46 0.00

2020.17-BMP5 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP5)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
613.00 7,472 0 618.20 17,147 61,939
613.10 7,618 755 618.30 17,402 63,667
613.20 7,765 1,524 618.40 17,657 65,420
613.30 7,911 2,307 618.50 17,913 67,198
613.40 8,058 3,106 618.60 18,168 69,002
613.50 8,204 3,919 618.70 18,423 70,832
613.60 8,350 4,747 618.80 18,678 72,687
613.70 8,497 5,589 618.90 18,933 74,567
613.80 8,643 6,446 619.00 19,188 76,474
613.90 8,790 7,318 619.10 19,443 78,405
614.00 8,936 8,204 619.20 19,698 80,362
614.10 9,109 9,106 619.30 19,953 82,345
614.20 9,282 10,026 619.40 20,208 84,353
614.30 9,454 10,963 619.50 20,464 86,386
614.40 9,627 11,917 619.60 20,719 88,445
614.50 9,800 12,888 619.70 20,974 90,530
614.60 9,973 13,877 619.80 21,229 92,640
614.70 10,146 14,883 619.90 21,484 94,776
614.80 10,318 15,906 620.00 21,739 96,937
614.90 10,491 16,946
615.00 10,664 18,004
615.10 10,837 19,079
615.20 11,010 20,171
615.30 11,182 21,281
615.40 11,355 22,408
615.50 11,528 23,552
615.60 11,701 24,713
615.70 11,874 25,892
615.80 12,046 27,088
615.90 12,219 28,301
616.00 12,392 29,532
616.10 12,604 30,782
616.20 12,817 32,053
616.30 13,029 33,345
616.40 13,241 34,659
616.50 13,453 35,993
616.60 13,666 37,349
616.70 13,878 38,726
616.80 14,090 40,125
616.90 14,302 41,544
617.00 14,515 42,985
617.10 14,727 44,447
617.20 14,939 45,931
617.30 15,151 47,435
617.40 15,363 48,961
617.50 15,576 50,508
617.60 15,788 52,076
617.70 16,000 53,665
617.80 16,212 55,276
617.90 16,425 56,908
618.00 16,637 58,561
618.10 16,892 60,237

2020.17-BMP5 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.050 ac Runoff Depth=3.09"
Flow Length=487' Tc=26.5 min CN=73 Runoff=23.26 cfs 2.072 af
Subcatchment 2S: (Post Developed) Runoff Area=8.070 ac Runoff Depth=4.41"
Tc=5.0 min CN=86 Runoff=62.26 cfs 2.965 af
Pond 3P: (BMP5) Peak Elev=618.02' Storage=58,974 cf Inflow=62.26 cfs 2.965 af
Primary=28.38 cfs 2.965 af Secondary=0.00 cfs 0.000 af Outflow=28.38 cfs 2.965 af
Total Runoff Area = 16.120 ac Runoff Volume = 5.037 af Average Runoff Depth = 3.75"
80.52% Pervious Area = 12.980 ac 19.48% Impervious Area = 3.140 ac

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 23.26 cfs @ 12.21 hrs, Volume= 2.072 af, Depth= 3.09"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description _
8.050 73 Woods, Fair, HSG C _
8.050 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) _ (cfs)
22.5 100 0.0637 0.07 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.0 387 0.1050 1.62 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
26.5 487 Total

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 3.09 0.00
2.00 0.13 0.00 0.00 106.00 6.00 3.09 0.00
4.00 0.29 0.00 0.00 108.00 6.00 3.09 0.00
6.00 0.48 0.00 0.00 110.00 6.00 3.09 0.00
8.00 0.72 0.00 0.00 112.00 6.00 3.09 0.00
10.00 1.09 0.03 0.21 114.00 6.00 3.09 0.00
12.00 3.98 1.51 11.67 116.00 6.00 3.09 0.00
14.00 4.92 2.22 1.72 118.00 6.00 3.09 0.00
16.00 5.28 2.50 1.00 120.00 6.00 3.09 0.00
18.00 5.53 2.70 0.75 122.00 6.00 3.09 0.00
20.00 5.71 2.85 0.56 124.00 6.00 3.09 0.00
22.00 5.86 2.97 0.49 126.00 6.00 3.09 0.00
24.00 6.00 3.09 0.45 128.00 6.00 3.09 0.00
26.00 6.00 3.09 0.00 130.00 6.00 3.09 0.00
28.00 6.00 3.09 0.00 132.00 6.00 3.09 0.00
30.00 6.00 3.09 0.00 134.00 6.00 3.09 0.00
32.00 6.00 3.09 0.00 136.00 6.00 3.09 0.00
34.00 6.00 3.09 0.00 138.00 6.00 3.09 0.00
36.00 6.00 3.09 0.00 140.00 6.00 3.09 0.00
38.00 6.00 3.09 0.00 142.00 6.00 3.09 0.00
40.00 6.00 3.09 0.00 144.00 6.00 3.09 0.00
42.00 6.00 3.09 0.00 146.00 6.00 3.09 0.00
44.00 6.00 3.09 0.00 148.00 6.00 3.09 0.00
46.00 6.00 3.09 0.00 150.00 6.00 3.09 0.00
48.00 6.00 3.09 0.00 152.00 6.00 3.09 0.00
50.00 6.00 3.09 0.00 154.00 6.00 3.09 0.00
52.00 6.00 3.09 0.00 156.00 6.00 3.09 0.00
54.00 6.00 3.09 0.00 158.00 6.00 3.09 0.00
56.00 6.00 3.09 0.00 160.00 6.00 3.09 0.00
58.00 6.00 3.09 0.00 162.00 6.00 3.09 0.00
60.00 6.00 3.09 0.00 164.00 6.00 3.09 0.00
62.00 6.00 3.09 0.00 166.00 6.00 3.09 0.00
64.00 6.00 3.09 0.00 168.00 6.00 3.09 0.00
66.00 6.00 3.09 0.00 170.00 6.00 3.09 0.00
68.00 6.00 3.09 0.00 172.00 6.00 3.09 0.00
70.00 6.00 3.09 0.00 174.00 6.00 3.09 0.00
72.00 6.00 3.09 0.00 176.00 6.00 3.09 0.00
74.00 6.00 3.09 0.00 178.00 6.00 3.09 0.00
76.00 6.00 3.09 0.00 180.00 6.00 3.09 0.00
78.00 6.00 3.09 0.00 182.00 6.00 3.09 0.00
80.00 6.00 3.09 0.00 184.00 6.00 3.09 0.00
82.00 6.00 3.09 0.00 186.00 6.00 3.09 0.00
84.00 6.00 3.09 0.00 188.00 6.00 3.09 0.00
86.00 6.00 3.09 0.00 190.00 6.00 3.09 0.00
88.00 6.00 3.09 0.00 192.00 6.00 3.09 0.00
90.00 6.00 3.09 0.00 194.00 6.00 3.09 0.00
92.00 6.00 3.09 0.00 196.00 6.00 3.09 0.00
94.00 6.00 3.09 0.00 198.00 6.00 3.09 0.00
96.00 6.00 3.09 0.00 200.00 6.00 3.09 0.00
98.00 6.00 3.09 0.00
100.00 6.00 3.09 0.00
102.00 6.00 3.09 0.00

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 62.26 cfs @ 11.96 hrs, Volume= 2.965 af, Depth= 4.41"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
3.140 98 Paved parking & roofs
4.930 79 50-75% Grass cover, Fair, HSG C
8.070 86 Weighted Average
4.930 Pervious Area
3.140 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 4.41 0.00
2.00 0.13 0.00 0.00 106.00 6.00 4.41 0.00
4.00 0.29 0.00 0.00 108.00 6.00 4.41 0.00
6.00 0.48 0.01 0.14 110.00 6.00 4.41 0.00
8.00 0.72 0.08 0.37 112.00 6.00 4.41 0.00
10.00 1.09 0.24 1.00 114.00 6.00 4.41 0.00
12.00 3.98 2.53 52.21 116.00 6.00 4.41 0.00
14.00 4.92 3.39 1.75 118.00 6.00 4.41 0.00
16.00 5.28 3.73 1.08 120.00 6.00 4.41 0.00
18.00 5.53 3.96 0.84 122.00 6.00 4.41 0.00
20.00 5.71 4.14 0.61 124.00 6.00 4.41 0.00
22.00 5.86 4.28 0.56 126.00 6.00 4.41 0.00
24.00 6.00 4.41 0.51 128.00 6.00 4.41 0.00
26.00 6.00 4.41 0.00 130.00 6.00 4.41 0.00
28.00 6.00 4.41 0.00 132.00 6.00 4.41 0.00
30.00 6.00 4.41 0.00 134.00 6.00 4.41 0.00
32.00 6.00 4.41 0.00 136.00 6.00 4.41 0.00
34.00 6.00 4.41 0.00 138.00 6.00 4.41 0.00
36.00 6.00 4.41 0.00 140.00 6.00 4.41 0.00
38.00 6.00 4.41 0.00 142.00 6.00 4.41 0.00
40.00 6.00 4.41 0.00 144.00 6.00 4.41 0.00
42.00 6.00 4.41 0.00 146.00 6.00 4.41 0.00
44.00 6.00 4.41 0.00 148.00 6.00 4.41 0.00
46.00 6.00 4.41 0.00 150.00 6.00 4.41 0.00
48.00 6.00 4.41 0.00 152.00 6.00 4.41 0.00
50.00 6.00 4.41 0.00 154.00 6.00 4.41 0.00
52.00 6.00 4.41 0.00 156.00 6.00 4.41 0.00
54.00 6.00 4.41 0.00 158.00 6.00 4.41 0.00
56.00 6.00 4.41 0.00 160.00 6.00 4.41 0.00
58.00 6.00 4.41 0.00 162.00 6.00 4.41 0.00
60.00 6.00 4.41 0.00 164.00 6.00 4.41 0.00
62.00 6.00 4.41 0.00 166.00 6.00 4.41 0.00
64.00 6.00 4.41 0.00 168.00 6.00 4.41 0.00
66.00 6.00 4.41 0.00 170.00 6.00 4.41 0.00
68.00 6.00 4.41 0.00 172.00 6.00 4.41 0.00
70.00 6.00 4.41 0.00 174.00 6.00 4.41 0.00
72.00 6.00 4.41 0.00 176.00 6.00 4.41 0.00
74.00 6.00 4.41 0.00 178.00 6.00 4.41 0.00
76.00 6.00 4.41 0.00 180.00 6.00 4.41 0.00
78.00 6.00 4.41 0.00 182.00 6.00 4.41 0.00
80.00 6.00 4.41 0.00 184.00 6.00 4.41 0.00
82.00 6.00 4.41 0.00 186.00 6.00 4.41 0.00
84.00 6.00 4.41 0.00 188.00 6.00 4.41 0.00
86.00 6.00 4.41 0.00 190.00 6.00 4.41 0.00
88.00 6.00 4.41 0.00 192.00 6.00 4.41 0.00
90.00 6.00 4.41 0.00 194.00 6.00 4.41 0.00
92.00 6.00 4.41 0.00 196.00 6.00 4.41 0.00
94.00 6.00 4.41 0.00 198.00 6.00 4.41 0.00
96.00 6.00 4.41 0.00 200.00 6.00 4.41 0.00
98.00 6.00 4.41 0.00
100.00 6.00 4.41 0.00
102.00 6.00 4.41 0.00

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP5)
Inflow Area = 8.070 ac, Inflow Depth = 4.41" for 25-yr Concord event
Inflow = 62.26 cfs @ 11.96 hrs, Volume= 2.965 af
Outflow = 28.38 cfs @ 12.05 hrs, Volume= 2.965 af, Atten= 54%, Lag= 5.4 min
Primary = 28.38 cfs @ 12.05 hrs, Volume= 2.965 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 618.02' @ 12.05 hrs Surf.Area= 16,700 sf Storage= 58,974 cf
Plug-Flow detention time= 488.1 min calculated for 2.965 af(100% of inflow)
Center-of-Mass det. time= 488.1 min ( 1,281.7 - 793.6 )
Volume Invert Avail.Storage Storage Description
#1 613.00' 96,937 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
613.00 7,472 0 0
614.00 8,936 8,204 8,204
616.00 12,392 21,328 29,532
618.00 16,637 29,029 58,561
620.00 21,739 38,376 96,937
Device Routing Invert Outlet Devices
#1 Primary 604.50' 18.0" x 89.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 604.00' S= 0.0056 '/' Cc= 0.900 n= 0.013
#2 Device 1 613.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.113 0.158 0.204 0.249 0.294 0.340
#3 Device 1 615.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 617.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 618.50' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=28.38 cfs @ 12.05 hrs HW=618.02' (Free Discharge)
4-1=Culvert (Barrel Controls 28.38 cfs @ 16.06 fps)
2=Exfiltration (Passes < 0.30 cfs potential flow)
3=Orifice/Grate (Passes < 1.57 cfs potential flow)
4=Top of Riser (Passes < 29.23 cfs potential flow)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=613.00' (Free Discharge)
L5=Spillway ( Controls 0.00 cfs)

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP5)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 613.00 0.00 0.00 0.00
5.00 0.04 35 613.00 0.00 0.00 0.00
10.00 1.00 6,289 613.78 0.09 0.09 0.00
15.00 1.39 43,099 617.01 1.57 1.57 0.00
20.00 0.61 34,531 616.39 1.23 1.23 0.00
25.00 0.00 24,414 615.57 0.72 0.72 0.00
30.00 0.00 18,304 615.03 0.16 0.16 0.00
35.00 0.00 15,543 614.76 0.15 0.15 0.00
40.00 0.00 12,993 614.51 0.14 0.14 0.00
45.00 0.00 10,645 614.27 0.12 0.12 0.00
50.00 0.00 8,491 614.03 0.11 0.11 0.00
55.00 0.00 6,617 613.82 0.09 0.09 0.00
60.00 0.00 5,133 613.65 0.07 0.07 0.00
65.00 0.00 3,967 613.51 0.06 0.06 0.00
70.00 0.00 3,056 613.39 0.04 0.04 0.00
75.00 0.00 2,349 613.31 0.03 0.03 0.00
80.00 0.00 1,802 613.24 0.03 0.03 0.00
85.00 0.00 1,380 613.18 0.02 0.02 0.00
90.00 0.00 1,056 613.14 0.02 0.02 0.00
95.00 0.00 807 613.11 0.01 0.01 0.00
100.00 0.00 616 613.08 0.01 0.01 0.00
105.00 0.00 470 613.06 0.01 0.01 0.00
110.00 0.00 359 613.05 0.01 0.01 0.00
115.00 0.00 274 613.04 0.00 0.00 0.00
120.00 0.00 209 613.03 0.00 0.00 0.00
125.00 0.00 160 613.02 0.00 0.00 0.00
130.00 0.00 122 613.02 0.00 0.00 0.00
135.00 0.00 93 613.01 0.00 0.00 0.00
140.00 0.00 71 613.01 0.00 0.00 0.00
145.00 0.00 54 613.01 0.00 0.00 0.00
150.00 0.00 41 613.01 0.00 0.00 0.00
155.00 0.00 31 613.00 0.00 0.00 0.00
160.00 0.00 24 613.00 0.00 0.00 0.00
165.00 0.00 18 613.00 0.00 0.00 0.00
170.00 0.00 14 613.00 0.00 0.00 0.00
175.00 0.00 11 613.00 0.00 0.00 0.00
180.00 0.00 8 613.00 0.00 0.00 0.00
185.00 0.00 6 613.00 0.00 0.00 0.00
190.00 0.00 5 613.00 0.00 0.00 0.00
195.00 0.00 4 613.00 0.00 0.00 0.00
200.00 0.00 3 613.00 0.00 0.00 0.00

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP5)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
613.00 0.00 0.00 0.00 618.20 28.58 28.58 0.00
613.10 0.01 0.01 0.00 618.30 28.69 28.69 0.00
613.20 0.02 0.02 0.00 618.40 28.80 28.80 0.00
613.30 0.03 0.03 0.00 618.50 28.91 28.91 0.00
613.40 0.05 0.05 0.00 618.60 29.87 29.02 0.85
613.50 0.06 0.06 0.00 618.70 31.53 29.13 2.40
613.60 0.07 0.07 0.00 618.80 33.66 29.24 4.42
613.70 0.08 0.08 0.00 618.90 36.18 29.35 6.83
613.80 0.09 0.09 0.00 619.00 39.01 29.46 9.55
613.90 0.10 0.10 0.00 619.10 42.12 29.57 12.55
614.00 0.11 0.11 0.00 619.20 45.32 29.68 15.64
614.10 0.12 0.12 0.00 619.30 48.68 29.79 18.89
614.20 0.12 0.12 0.00 619.40 52.39 29.90 22.50
614.30 0.13 0.13 0.00 619.50 56.30 30.00 26.30
614.40 0.13 0.13 0.00 619.60 60.51 30.11 30.40
614.50 0.14 0.14 0.00 619.70 64.92 30.22 34.70
614.60 0.14 0.14 0.00 619.80 69.45 30.32 39.13
614.70 0.14 0.14 0.00 619.90 74.16 30.43 43.73
614.80 0.15 0.15 0.00 620.00 78.94 30.53 48.41
614.90 0.15 0.15 0.00
615.00 0.16 0.16 0.00
615.10 0.19 0.19 0.00
615.20 0.28 0.28 0.00
615.30 0.40 0.40 0.00
615.40 0.54 0.54 0.00
615.50 0.65 0.65 0.00
615.60 0.74 0.74 0.00
615.70 0.82 0.82 0.00
615.80 0.90 0.90 0.00
615.90 0.96 0.96 0.00
616.00 1.02 1.02 0.00
616.10 1.08 1.08 0.00
616.20 1.13 1.13 0.00
616.30 1.19 1.19 0.00
616.40 1.24 1.24 0.00
616.50 1.28 1.28 0.00
616.60 1.33 1.33 0.00
616.70 1.37 1.37 0.00
616.80 1.42 1.42 0.00
616.90 1.46 1.46 0.00
617.00 1.50 1.50 0.00
617.10 2.57 2.57 0.00
617.20 4.50 4.50 0.00
617.30 6.99 6.99 0.00
617.40 9.93 9.93 0.00
617.50 13.25 13.25 0.00
617.60 16.92 16.92 0.00
617.70 20.91 20.91 0.00
617.80 25.19 25.19 0.00
617.90 28.24 28.24 0.00
618.00 28.35 28.35 0.00
618.10 28.46 28.46 0.00

2020.17-BMP5 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP5)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
613.00 7,472 0 618.20 17,147 61,939
613.10 7,618 755 618.30 17,402 63,667
613.20 7,765 1,524 618.40 17,657 65,420
613.30 7,911 2,307 618.50 17,913 67,198
613.40 8,058 3,106 618.60 18,168 69,002
613.50 8,204 3,919 618.70 18,423 70,832
613.60 8,350 4,747 618.80 18,678 72,687
613.70 8,497 5,589 618.90 18,933 74,567
613.80 8,643 6,446 619.00 19,188 76,474
613.90 8,790 7,318 619.10 19,443 78,405
614.00 8,936 8,204 619.20 19,698 80,362
614.10 9,109 9,106 619.30 19,953 82,345
614.20 9,282 10,026 619.40 20,208 84,353
614.30 9,454 10,963 619.50 20,464 86,386
614.40 9,627 11,917 619.60 20,719 88,445
614.50 9,800 12,888 619.70 20,974 90,530
614.60 9,973 13,877 619.80 21,229 92,640
614.70 10,146 14,883 619.90 21,484 94,776
614.80 10,318 15,906 620.00 21,739 96,937
614.90 10,491 16,946
615.00 10,664 18,004
615.10 10,837 19,079
615.20 11,010 20,171
615.30 11,182 21,281
615.40 11,355 22,408
615.50 11,528 23,552
615.60 11,701 24,713
615.70 11,874 25,892
615.80 12,046 27,088
615.90 12,219 28,301
616.00 12,392 29,532
616.10 12,604 30,782
616.20 12,817 32,053
616.30 13,029 33,345
616.40 13,241 34,659
616.50 13,453 35,993
616.60 13,666 37,349
616.70 13,878 38,726
616.80 14,090 40,125
616.90 14,302 41,544
617.00 14,515 42,985
617.10 14,727 44,447
617.20 14,939 45,931
617.30 15,151 47,435
617.40 15,363 48,961
617.50 15,576 50,508
617.60 15,788 52,076
617.70 16,000 53,665
617.80 16,212 55,276
617.90 16,425 56,908
618.00 16,637 58,561
618.10 16,892 60,237

2020.17-BMP5 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=8.050 ac Runoff Depth=3.76"
Flow Length=487' Tc=26.5 min CN=73 Runoff=28.41 cfs 2.525 af
Subcatchment 2S: (Post Developed) Runoff Area=8.070 ac Runoff Depth=5.17"
Tc=5.0 min CN=86 Runoff=72.29 cfs 3.479 af
Pond 3P: (BMP5) Peak Elev=618.52' Storage=67,500 cf Inflow=72.29 cfs 3.479 af
Primary=28.93 cfs 3.479 af Secondary=0.08 cfs 0.000 af Outflow=29.01 cfs 3.479 af
Total Runoff Area = 16.120 ac Runoff Volume = 6.004 af Average Runoff Depth = 4.47"
80.52% Pervious Area = 12.980 ac 19.48% Impervious Area = 3.140 ac

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 28.41 cfs @ 12.21 hrs, Volume= 2.525 af, Depth= 3.76"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description _
8.050 73 Woods, Fair, HSG C _
8.050 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) _ (cfs)
22.5 100 0.0637 0.07 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.0 387 0.1050 1.62 Shallow Concentrated Flow,
Woodland Kv= 5.0 fps
26.5 487 Total

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 3.76 0.00
2.00 0.15 0.00 0.00 106.00 6.80 3.76 0.00
4.00 0.33 0.00 0.00 108.00 6.80 3.76 0.00
6.00 0.54 0.00 0.00 110.00 6.80 3.76 0.00
8.00 0.82 0.00 0.01 112.00 6.80 3.76 0.00
10.00 1.23 0.06 0.34 114.00 6.80 3.76 0.00
12.00 4.51 1.90 14.62 116.00 6.80 3.76 0.00
14.00 5.58 2.74 2.03 118.00 6.80 3.76 0.00
16.00 5.98 3.08 1.18 120.00 6.80 3.76 0.00
18.00 6.26 3.31 0.88 122.00 6.80 3.76 0.00
20.00 6.47 3.49 0.65 124.00 6.80 3.76 0.00
22.00 6.64 3.63 0.57 126.00 6.80 3.76 0.00
24.00 6.80 3.76 0.53 128.00 6.80 3.76 0.00
26.00 6.80 3.76 0.00 130.00 6.80 3.76 0.00
28.00 6.80 3.76 0.00 132.00 6.80 3.76 0.00
30.00 6.80 3.76 0.00 134.00 6.80 3.76 0.00
32.00 6.80 3.76 0.00 136.00 6.80 3.76 0.00
34.00 6.80 3.76 0.00 138.00 6.80 3.76 0.00
36.00 6.80 3.76 0.00 140.00 6.80 3.76 0.00
38.00 6.80 3.76 0.00 142.00 6.80 3.76 0.00
40.00 6.80 3.76 0.00 144.00 6.80 3.76 0.00
42.00 6.80 3.76 0.00 146.00 6.80 3.76 0.00
44.00 6.80 3.76 0.00 148.00 6.80 3.76 0.00
46.00 6.80 3.76 0.00 150.00 6.80 3.76 0.00
48.00 6.80 3.76 0.00 152.00 6.80 3.76 0.00
50.00 6.80 3.76 0.00 154.00 6.80 3.76 0.00
52.00 6.80 3.76 0.00 156.00 6.80 3.76 0.00
54.00 6.80 3.76 0.00 158.00 6.80 3.76 0.00
56.00 6.80 3.76 0.00 160.00 6.80 3.76 0.00
58.00 6.80 3.76 0.00 162.00 6.80 3.76 0.00
60.00 6.80 3.76 0.00 164.00 6.80 3.76 0.00
62.00 6.80 3.76 0.00 166.00 6.80 3.76 0.00
64.00 6.80 3.76 0.00 168.00 6.80 3.76 0.00
66.00 6.80 3.76 0.00 170.00 6.80 3.76 0.00
68.00 6.80 3.76 0.00 172.00 6.80 3.76 0.00
70.00 6.80 3.76 0.00 174.00 6.80 3.76 0.00
72.00 6.80 3.76 0.00 176.00 6.80 3.76 0.00
74.00 6.80 3.76 0.00 178.00 6.80 3.76 0.00
76.00 6.80 3.76 0.00 180.00 6.80 3.76 0.00
78.00 6.80 3.76 0.00 182.00 6.80 3.76 0.00
80.00 6.80 3.76 0.00 184.00 6.80 3.76 0.00
82.00 6.80 3.76 0.00 186.00 6.80 3.76 0.00
84.00 6.80 3.76 0.00 188.00 6.80 3.76 0.00
86.00 6.80 3.76 0.00 190.00 6.80 3.76 0.00
88.00 6.80 3.76 0.00 192.00 6.80 3.76 0.00
90.00 6.80 3.76 0.00 194.00 6.80 3.76 0.00
92.00 6.80 3.76 0.00 196.00 6.80 3.76 0.00
94.00 6.80 3.76 0.00 198.00 6.80 3.76 0.00
96.00 6.80 3.76 0.00 200.00 6.80 3.76 0.00
98.00 6.80 3.76 0.00
100.00 6.80 3.76 0.00
102.00 6.80 3.76 0.00

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 72.29 cfs @ 11.96 hrs, Volume= 3.479 af, Depth= 5.17"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
3.140 98 Paved parking & roofs
4.930 79 50-75% Grass cover, Fair, HSG C
8.070 86 Weighted Average
4.930 Pervious Area
3.140 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 5.17 0.00
2.00 0.15 0.00 0.00 106.00 6.80 5.17 0.00
4.00 0.33 0.00 0.00 108.00 6.80 5.17 0.00
6.00 0.54 0.03 0.21 110.00 6.80 5.17 0.00
8.00 0.82 0.11 0.49 112.00 6.80 5.17 0.00
10.00 1.23 0.32 1.24 114.00 6.80 5.17 0.00
12.00 4.51 3.01 60.46 116.00 6.80 5.17 0.00
14.00 5.58 4.01 2.01 118.00 6.80 5.17 0.00
16.00 5.98 4.39 1.24 120.00 6.80 5.17 0.00
18.00 6.26 4.66 0.96 122.00 6.80 5.17 0.00
20.00 6.47 4.86 0.70 124.00 6.80 5.17 0.00
22.00 6.64 5.02 0.64 126.00 6.80 5.17 0.00
24.00 6.80 5.17 0.59 128.00 6.80 5.17 0.00
26.00 6.80 5.17 0.00 130.00 6.80 5.17 0.00
28.00 6.80 5.17 0.00 132.00 6.80 5.17 0.00
30.00 6.80 5.17 0.00 134.00 6.80 5.17 0.00
32.00 6.80 5.17 0.00 136.00 6.80 5.17 0.00
34.00 6.80 5.17 0.00 138.00 6.80 5.17 0.00
36.00 6.80 5.17 0.00 140.00 6.80 5.17 0.00
38.00 6.80 5.17 0.00 142.00 6.80 5.17 0.00
40.00 6.80 5.17 0.00 144.00 6.80 5.17 0.00
42.00 6.80 5.17 0.00 146.00 6.80 5.17 0.00
44.00 6.80 5.17 0.00 148.00 6.80 5.17 0.00
46.00 6.80 5.17 0.00 150.00 6.80 5.17 0.00
48.00 6.80 5.17 0.00 152.00 6.80 5.17 0.00
50.00 6.80 5.17 0.00 154.00 6.80 5.17 0.00
52.00 6.80 5.17 0.00 156.00 6.80 5.17 0.00
54.00 6.80 5.17 0.00 158.00 6.80 5.17 0.00
56.00 6.80 5.17 0.00 160.00 6.80 5.17 0.00
58.00 6.80 5.17 0.00 162.00 6.80 5.17 0.00
60.00 6.80 5.17 0.00 164.00 6.80 5.17 0.00
62.00 6.80 5.17 0.00 166.00 6.80 5.17 0.00
64.00 6.80 5.17 0.00 168.00 6.80 5.17 0.00
66.00 6.80 5.17 0.00 170.00 6.80 5.17 0.00
68.00 6.80 5.17 0.00 172.00 6.80 5.17 0.00
70.00 6.80 5.17 0.00 174.00 6.80 5.17 0.00
72.00 6.80 5.17 0.00 176.00 6.80 5.17 0.00
74.00 6.80 5.17 0.00 178.00 6.80 5.17 0.00
76.00 6.80 5.17 0.00 180.00 6.80 5.17 0.00
78.00 6.80 5.17 0.00 182.00 6.80 5.17 0.00
80.00 6.80 5.17 0.00 184.00 6.80 5.17 0.00
82.00 6.80 5.17 0.00 186.00 6.80 5.17 0.00
84.00 6.80 5.17 0.00 188.00 6.80 5.17 0.00
86.00 6.80 5.17 0.00 190.00 6.80 5.17 0.00
88.00 6.80 5.17 0.00 192.00 6.80 5.17 0.00
90.00 6.80 5.17 0.00 194.00 6.80 5.17 0.00
92.00 6.80 5.17 0.00 196.00 6.80 5.17 0.00
94.00 6.80 5.17 0.00 198.00 6.80 5.17 0.00
96.00 6.80 5.17 0.00 200.00 6.80 5.17 0.00
98.00 6.80 5.17 0.00
100.00 6.80 5.17 0.00
102.00 6.80 5.17 0.00

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP5)
Inflow Area = 8.070 ac, Inflow Depth = 5.17" for 50-yr Concord event
Inflow = 72.29 cfs @ 11.96 hrs, Volume= 3.479 af
Outflow = 29.01 cfs @ 12.05 hrs, Volume= 3.479 af, Atten= 60%, Lag= 5.8 min
Primary = 28.93 cfs @ 12.05 hrs, Volume= 3.479 af
Secondary= 0.08 cfs @ 12.05 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 618.52' @ 12.05 hrs Surf.Area= 17,955 sf Storage= 67,500 cf
Plug-Flow detention time= 433.2 min calculated for 3.479 af(100% of inflow)
Center-of-Mass det. time= 433.2 min ( 1,222.3 - 789.2 )
Volume Invert Avail.Storage Storage Description
#1 613.00' 96,937 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
613.00 7,472 0 0
614.00 8,936 8,204 8,204
616.00 12,392 21,328 29,532
618.00 16,637 29,029 58,561
620.00 21,739 38,376 96,937
Device Routing Invert Outlet Devices
#1 Primary 604.50' 18.0" x 89.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 604.00' S= 0.0056 '/' Cc= 0.900 n= 0.013
#2 Device 1 613.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.113 0.158 0.204 0.249 0.294 0.340
#3 Device 1 615.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 617.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 618.50' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=28.93 cfs @ 12.05 hrs HW=618.52' (Free Discharge)
4-1=Culvert (Barrel Controls 28.93 cfs @ 16.37 fps)
2=Exfiltration (Passes < 0.32 cfs potential flow)
3=Orifice/Grate (Passes < 1.71 cfs potential flow)
4=Top of Riser (Passes < 35.57 cfs potential flow)
Secondary OutFlow Max=0.05 cfs @ 12.05 hrs HW=618.52' (Free Discharge)
L5=Spillway (Weir Controls 0.05 cfs @ 0.33 fps)

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP5)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 613.00 0.00 0.00 0.00
5.00 0.09 150 613.02 0.00 0.00 0.00
10.00 1.24 8,382 614.02 0.11 0.11 0.00
15.00 1.60 43,459 617.03 1.77 1.77 0.00
20.00 0.70 36,317 616.52 1.29 1.29 0.00
25.00 0.00 25,881 615.70 0.82 0.82 0.00
30.00 0.00 18,623 615.06 0.17 0.17 0.00
35.00 0.00 15,823 614.79 0.15 0.15 0.00
40.00 0.00 13,252 614.54 0.14 0.14 0.00
45.00 0.00 10,883 614.29 0.13 0.13 0.00
50.00 0.00 8,709 614.06 0.12 0.12 0.00
55.00 0.00 6,795 613.84 0.09 0.09 0.00
60.00 0.00 5,273 613.66 0.07 0.07 0.00
65.00 0.00 4,076 613.52 0.06 0.06 0.00
70.00 0.00 3,142 613.40 0.05 0.05 0.00
75.00 0.00 2,415 613.31 0.04 0.04 0.00
80.00 0.00 1,853 613.24 0.03 0.03 0.00
85.00 0.00 1,419 613.19 0.02 0.02 0.00
90.00 0.00 1,086 613.14 0.02 0.02 0.00
95.00 0.00 830 613.11 0.01 0.01 0.00
100.00 0.00 634 613.08 0.01 0.01 0.00
105.00 0.00 484 613.06 0.01 0.01 0.00
110.00 0.00 369 613.05 0.01 0.01 0.00
115.00 0.00 282 613.04 0.00 0.00 0.00
120.00 0.00 215 613.03 0.00 0.00 0.00
125.00 0.00 164 613.02 0.00 0.00 0.00
130.00 0.00 125 613.02 0.00 0.00 0.00
135.00 0.00 96 613.01 0.00 0.00 0.00
140.00 0.00 73 613.01 0.00 0.00 0.00
145.00 0.00 56 613.01 0.00 0.00 0.00
150.00 0.00 42 613.01 0.00 0.00 0.00
155.00 0.00 32 613.00 0.00 0.00 0.00
160.00 0.00 25 613.00 0.00 0.00 0.00
165.00 0.00 19 613.00 0.00 0.00 0.00
170.00 0.00 14 613.00 0.00 0.00 0.00
175.00 0.00 11 613.00 0.00 0.00 0.00
180.00 0.00 8 613.00 0.00 0.00 0.00
185.00 0.00 6 613.00 0.00 0.00 0.00
190.00 0.00 5 613.00 0.00 0.00 0.00
195.00 0.00 4 613.00 0.00 0.00 0.00
200.00 0.00 3 613.00 0.00 0.00 0.00

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP5)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
613.00 0.00 0.00 0.00 618.20 28.58 28.58 0.00
613.10 0.01 0.01 0.00 618.30 28.69 28.69 0.00
613.20 0.02 0.02 0.00 618.40 28.80 28.80 0.00
613.30 0.03 0.03 0.00 618.50 28.91 28.91 0.00
613.40 0.05 0.05 0.00 618.60 29.87 29.02 0.85
613.50 0.06 0.06 0.00 618.70 31.53 29.13 2.40
613.60 0.07 0.07 0.00 618.80 33.66 29.24 4.42
613.70 0.08 0.08 0.00 618.90 36.18 29.35 6.83
613.80 0.09 0.09 0.00 619.00 39.01 29.46 9.55
613.90 0.10 0.10 0.00 619.10 42.12 29.57 12.55
614.00 0.11 0.11 0.00 619.20 45.32 29.68 15.64
614.10 0.12 0.12 0.00 619.30 48.68 29.79 18.89
614.20 0.12 0.12 0.00 619.40 52.39 29.90 22.50
614.30 0.13 0.13 0.00 619.50 56.30 30.00 26.30
614.40 0.13 0.13 0.00 619.60 60.51 30.11 30.40
614.50 0.14 0.14 0.00 619.70 64.92 30.22 34.70
614.60 0.14 0.14 0.00 619.80 69.45 30.32 39.13
614.70 0.14 0.14 0.00 619.90 74.16 30.43 43.73
614.80 0.15 0.15 0.00 620.00 78.94 30.53 48.41
614.90 0.15 0.15 0.00
615.00 0.16 0.16 0.00
615.10 0.19 0.19 0.00
615.20 0.28 0.28 0.00
615.30 0.40 0.40 0.00
615.40 0.54 0.54 0.00
615.50 0.65 0.65 0.00
615.60 0.74 0.74 0.00
615.70 0.82 0.82 0.00
615.80 0.90 0.90 0.00
615.90 0.96 0.96 0.00
616.00 1.02 1.02 0.00
616.10 1.08 1.08 0.00
616.20 1.13 1.13 0.00
616.30 1.19 1.19 0.00
616.40 1.24 1.24 0.00
616.50 1.28 1.28 0.00
616.60 1.33 1.33 0.00
616.70 1.37 1.37 0.00
616.80 1.42 1.42 0.00
616.90 1.46 1.46 0.00
617.00 1.50 1.50 0.00
617.10 2.57 2.57 0.00
617.20 4.50 4.50 0.00
617.30 6.99 6.99 0.00
617.40 9.93 9.93 0.00
617.50 13.25 13.25 0.00
617.60 16.92 16.92 0.00
617.70 20.91 20.91 0.00
617.80 25.19 25.19 0.00
617.90 28.24 28.24 0.00
618.00 28.35 28.35 0.00
618.10 28.46 28.46 0.00

2020.17-BMP5 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP5)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
613.00 7,472 0 618.20 17,147 61,939
613.10 7,618 755 618.30 17,402 63,667
613.20 7,765 1,524 618.40 17,657 65,420
613.30 7,911 2,307 618.50 17,913 67,198
613.40 8,058 3,106 618.60 18,168 69,002
613.50 8,204 3,919 618.70 18,423 70,832
613.60 8,350 4,747 618.80 18,678 72,687
613.70 8,497 5,589 618.90 18,933 74,567
613.80 8,643 6,446 619.00 19,188 76,474
613.90 8,790 7,318 619.10 19,443 78,405
614.00 8,936 8,204 619.20 19,698 80,362
614.10 9,109 9,106 619.30 19,953 82,345
614.20 9,282 10,026 619.40 20,208 84,353
614.30 9,454 10,963 619.50 20,464 86,386
614.40 9,627 11,917 619.60 20,719 88,445
614.50 9,800 12,888 619.70 20,974 90,530
614.60 9,973 13,877 619.80 21,229 92,640
614.70 10,146 14,883 619.90 21,484 94,776
614.80 10,318 15,906 620.00 21,739 96,937
614.90 10,491 16,946
615.00 10,664 18,004
615.10 10,837 19,079
615.20 11,010 20,171
615.30 11,182 21,281
615.40 11,355 22,408
615.50 11,528 23,552
615.60 11,701 24,713
615.70 11,874 25,892
615.80 12,046 27,088
615.90 12,219 28,301
616.00 12,392 29,532
616.10 12,604 30,782
616.20 12,817 32,053
616.30 13,029 33,345
616.40 13,241 34,659
616.50 13,453 35,993
616.60 13,666 37,349
616.70 13,878 38,726
616.80 14,090 40,125
616.90 14,302 41,544
617.00 14,515 42,985
617.10 14,727 44,447
617.20 14,939 45,931
617.30 15,151 47,435
617.40 15,363 48,961
617.50 15,576 50,508
617.60 15,788 52,076
617.70 16,000 53,665
617.80 16,212 55,276
617.90 16,425 56,908
618.00 16,637 58,561
618.10 16,892 60,237

SAND FILTER-6
,-, r- _ 1 - �\ \ _�
)IN
1 k
.........".''''',- jr --
i HI :.. , //,—:_Ili Ili --"
_ fii, ,,_ ,____..... ,
, i / .......„
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_ iiii ___ ,..;
ter_ j-
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4 �' to
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1
� I . ^ ' 1 nwev r
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t - _ - a[wMwrs ow) „=�„,;•4- M- //
I.nc u•eraws fnPJ � � _
—- - - _ ___ 7__ _ -_ _ ' ' I _ .,- 4):41*C:
\_ - ,,•• i 4 • 4. + # t + •
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♦ + + + +
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+ + ♦ t + 1,4 �+r moo fsaw-• ♦•♦•♦•♦ + ++
,r —,.........-z,\ \ \ ....„......,..,... , + + r + .0' ,
:--"
•� � ` _T

Mt. Pleasant, NC Brighton Park
Sand Filter Calculation 6
1. Calculate Runoff Coeff,(Rv)
Drainage area to filter,Ad= 9.94 ac
Impervious area to filter forebay= 4.38 ac.
Impervious percentage= 44.02%
Rv=0.05+0.9(la) = 0.44615628
2. Calculate req'd water quality volume(WQV) WQV=(Rv/1 x Ad/1 x 43560 sf/1 ac x Rd/1 x ft/12 in)
WQV= 16098 cf (used to size Af)
WQV= 0.3696 ac-ft.
Storage: Cum
Elev. Area Vol. Vol
618 12647 0 0
619 14371 13509 13509
620 16095 15233 28742
621 18019 17057 45799
622 19943 18981 64780
623 22071 21007 85787
624 24198 23134.5 108921.5
Calculate Depth for WQ Volume:
618 0
619.12 16098
620 28742
Elevation of WQ Volume= 619.12
3. Discount WQv:
0.75 x WQv 12073.73 cuft
4. Site Hydrologic Input Parameters:
Cn Pre= 74.0
Cn Post= 87.0 to pond
Table 4.8.3 Results of Hydrologic Calculations from HydroCad
Condition Q 1-year Q 10-yr. Q 25-yr Q 50 yr
Runoff
Pre Dev. 5.62 17.65 23.55 28.71
Post. Dev. 30.11 17.91 78.00 90.33
Routed 0.80 64.08 27.26 38.36
Peak Stage 620.59 622.36 622.84 623.27
Disch.Time 130 hours 0.7' Freeboard

5.Minimum Surface Area for Sand Media Equation 2:Minimum Surface Area for an Infiltration System
2012 SA(ft2) Dv•12
2 FS SA = FS* K•T
12074 DV(FT3) where: SA =required minimum surface area of infiltration system(fV)
FS =factor of safety(minimum of 2 is recommended)
2 K(in/hr) DV =design volume(ft')
72 T(hours) T =hmaximumydraulic conductivity
gti e il2hours)
6.Sediment Sand Sizing
12074 Design Volume(ft3)
6037 Sediment Chamber(ft3)
6037 Sand Chamber(ft3)
7.Sand Filter Drawdown Calculation
Coeff. Of Permeability of filter media=2 in/hr 0.166667 ft/hr
Volume of water drained in one hour=0.167 ft/hr x SA ft2= 335.3813 cf/hour 0.093 cfs
Drawdown Time=WQV/Drawdown Rate= 48.00 hrs 2 days
8.Underdrain Calculations:
78 I.f of underdrain shown; provide 6"perforated pvc pipe with 3/8"perforations spaces 3"o.c.-4 longitudinal rows
spaced 90 degrees apart.
122 I.f.of pipe I.f.x 4 rows/ft x 4 holes/ft= 1952 holes
50%of perforations= 976 holes
Capacity of one hole= 0.0083 cfs based upon CA(2gh)^0.5
Total Capacity= 8.1008 cfs which is 87.0 times the capacity of the sand filter.
Total Capacityof 6"PVC©0.50%is 0.40 cfs(0.20 cfs assuming 50%clogged) from Mannings and BMP Manual.
9.Antiflotation Calculation
Dimensions of Riser
8 Height of Riser,ft. 2 ft L
6 Area of Riser,s.f. 3 ft W
48 Volume of Riser,c.f. 0.5 ft
2995.2 Weight of Water©62.4 pcf
3294.72 Weight of water with safety factor of 1.1
82.6 Buoyant Wt.of Concrete=(145-62.4)pcf
1.48 Volume of Concrete Req'd in c.y.
39.89 Volume of Concrete Req'd in c.f.
48 Volume of Concrete in Structure(cf)
-8.11 Volume of Concrete Required(cf) (If negative,additional concrete weight not required)
1 ft thick
2.0 Length/Width

Brighton Park Latham-Walters Engineering, Inc.
16507-A Northcross Drive
Mt. Pleasant, NC Huntersville, NC 28078
10. Infiltration Rate
Q =Af(k)(h+df)/(df)
where Af= surface area of filter bed = 2012 sf
df =filter bed depth, ft. = 1.5 ft.
k = coefficient of permeability of filter media (ft/day) = 4 ft/day
h = average height of water above filter bed (ft) 1,2, etc.
h Q Q
cf/day cfs
1 13415.25 0.155
2 18781.35 0.217
3 24147.45' 0.279
4 29513.55 0.342
5 34879.65 0.404
6 40245.75 0.466
7 45611.85 0.528
8 50977.95 0.590
9 56344.05 0.652
10 61710.15 0.714

•
(Predeveloped)
e > 3P
(Post Developed) (BMP6)
(Subcat Reach 'On. MI Drainage Diagram for 2020.17-BMP6
Prepared by{enter your company name here} 1/23/2023
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC

2020.17-BMP6
Prepared by {enter your company name here} Page 2
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Area Listing (all nodes)
Area (acres) CN Description (subcats)
8.510 73 Woods, Fair, HSG C (1S)
5.560 79 50-75% Grass cover, Fair, HSG C (2S)
1.430 79 Pasture/grassland/range, Fair, HSG C (1S)
4.380 98 Paved parking & roofs (2S)
19.880

2020.17-BMP6 Type II 24-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 3
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.940 ac Runoff Depth=0.85"
Flow Length=598' Tc=37.6 min CN=74 Runoff=5.62 cfs 0.700 af
Subcatchment 2S: (Post Developed) Runoff Area=9.940 ac Runoff Depth=1.65"
Tc=5.0 min CN=87 Runoff=30.11 cfs 1.368 af
Pond 3P: (BMP6) Peak Elev=620.59' Storage=38,541 cf Inflow=30.11 cfs 1.368 af
Primary=0.80 cfs 1.368 af Secondary=0.00 cfs 0.000 af Outflow=0.80 cfs 1.368 af
Total Runoff Area = 19.880 ac Runoff Volume = 2.069 af Average Runoff Depth = 1.25"
77.97% Pervious Area = 15.500 ac 22.03% Impervious Area = 4.380 ac

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 4
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 5.62 cfs @ 12.37 hrs, Volume= 0.700 af, Depth= 0.85"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
8.510 73 Woods, Fair, HSG C
1.430 79 Pasture/grassland/range, Fair, HSG C
9.940 74 Weighted Average
9.940 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
32.8 100 0.0248 0.05 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.8 498 0.1210 1.74 Shallow Concentrated Flow,
_ Woodland Kv= 5.0 fps _
37.6 598 Total

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 5
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 0.85 0.00
2.00 0.06 0.00 0.00 106.00 2.90 0.85 0.00
4.00 0.14 0.00 0.00 108.00 2.90 0.85 0.00
6.00 0.23 0.00 0.00 110.00 2.90 0.85 0.00
8.00 0.35 0.00 0.00 112.00 2.90 0.85 0.00
10.00 0.52 0.00 0.00 114.00 2.90 0.85 0.00
12.00 1.92 0.31 1.17 116.00 2.90 0.85 0.00
14.00 2.38 0.54 0.78 118.00 2.90 0.85 0.00
16.00 2.55 0.64 0.44 120.00 2.90 0.85 0.00
18.00 2.67 0.71 0.33 122.00 2.90 0.85 0.00
20.00 2.76 0.76 0.25 124.00 2.90 0.85 0.00
22.00 2.83 0.80 0.22 126.00 2.90 0.85 0.00
24.00 2.90 0.85 0.20 128.00 2.90 0.85 0.00
26.00 2.90 0.85 0.00 130.00 2.90 0.85 0.00
28.00 2.90 0.85 0.00 132.00 2.90 0.85 0.00
30.00 2.90 0.85 0.00 134.00 2.90 0.85 0.00
32.00 2.90 0.85 0.00 136.00 2.90 0.85 0.00
34.00 2.90 0.85 0.00 138.00 2.90 0.85 0.00
36.00 2.90 0.85 0.00 140.00 2.90 0.85 0.00
38.00 2.90 0.85 0.00 142.00 2.90 0.85 0.00
40.00 2.90 0.85 0.00 144.00 2.90 0.85 0.00
42.00 2.90 0.85 0.00 146.00 2.90 0.85 0.00
44.00 2.90 0.85 0.00 148.00 2.90 0.85 0.00
46.00 2.90 0.85 0.00 150.00 2.90 0.85 0.00
48.00 2.90 0.85 0.00 152.00 2.90 0.85 0.00
50.00 2.90 0.85 0.00 154.00 2.90 0.85 0.00
52.00 2.90 0.85 0.00 156.00 2.90 0.85 0.00
54.00 2.90 0.85 0.00 158.00 2.90 0.85 0.00
56.00 2.90 0.85 0.00 160.00 2.90 0.85 0.00
58.00 2.90 0.85 0.00 162.00 2.90 0.85 0.00
60.00 2.90 0.85 0.00 164.00 2.90 0.85 0.00
62.00 2.90 0.85 0.00 166.00 2.90 0.85 0.00
64.00 2.90 0.85 0.00 168.00 2.90 0.85 0.00
66.00 2.90 0.85 0.00 170.00 2.90 0.85 0.00
68.00 2.90 0.85 0.00 172.00 2.90 0.85 0.00
70.00 2.90 0.85 0.00 174.00 2.90 0.85 0.00
72.00 2.90 0.85 0.00 176.00 2.90 0.85 0.00
74.00 2.90 0.85 0.00 178.00 2.90 0.85 0.00
76.00 2.90 0.85 0.00 180.00 2.90 0.85 0.00
78.00 2.90 0.85 0.00 182.00 2.90 0.85 0.00
80.00 2.90 0.85 0.00 184.00 2.90 0.85 0.00
82.00 2.90 0.85 0.00 186.00 2.90 0.85 0.00
84.00 2.90 0.85 0.00 188.00 2.90 0.85 0.00
86.00 2.90 0.85 0.00 190.00 2.90 0.85 0.00
88.00 2.90 0.85 0.00 192.00 2.90 0.85 0.00
90.00 2.90 0.85 0.00 194.00 2.90 0.85 0.00
92.00 2.90 0.85 0.00 196.00 2.90 0.85 0.00
94.00 2.90 0.85 0.00 198.00 2.90 0.85 0.00
96.00 2.90 0.85 0.00 200.00 2.90 0.85 0.00
98.00 2.90 0.85 0.00
100.00 2.90 0.85 0.00
102.00 2.90 0.85 0.00

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 6
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 30.11 cfs @ 11.96 hrs, Volume= 1.368 af, Depth= 1.65"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 1-yr Concord Rainfall=2.90"
Area (ac) CN Description
4.380 98 Paved parking & roofs
5.560 79 50-75% Grass cover, Fair, HSG C
9.940 87 Weighted Average
5.560 Pervious Area
4.380 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 7
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 2.90 1.65 0.00
2.00 0.06 0.00 0.00 106.00 2.90 1.65 0.00
4.00 0.14 0.00 0.00 108.00 2.90 1.65 0.00
6.00 0.23 0.00 0.00 110.00 2.90 1.65 0.00
8.00 0.35 0.00 0.04 112.00 2.90 1.65 0.00
10.00 0.52 0.03 0.27 114.00 2.90 1.65 0.00
12.00 1.92 0.85 25.74 116.00 2.90 1.65 0.00
14.00 2.38 1.21 0.92 118.00 2.90 1.65 0.00
16.00 2.55 1.35 0.58 120.00 2.90 1.65 0.00
18.00 2.67 1.46 0.45 122.00 2.90 1.65 0.00
20.00 2.76 1.53 0.33 124.00 2.90 1.65 0.00
22.00 2.83 1.59 0.30 126.00 2.90 1.65 0.00
24.00 2.90 1.65 0.28 128.00 2.90 1.65 0.00
26.00 2.90 1.65 0.00 130.00 2.90 1.65 0.00
28.00 2.90 1.65 0.00 132.00 2.90 1.65 0.00
30.00 2.90 1.65 0.00 134.00 2.90 1.65 0.00
32.00 2.90 1.65 0.00 136.00 2.90 1.65 0.00
34.00 2.90 1.65 0.00 138.00 2.90 1.65 0.00
36.00 2.90 1.65 0.00 140.00 2.90 1.65 0.00
38.00 2.90 1.65 0.00 142.00 2.90 1.65 0.00
40.00 2.90 1.65 0.00 144.00 2.90 1.65 0.00
42.00 2.90 1.65 0.00 146.00 2.90 1.65 0.00
44.00 2.90 1.65 0.00 148.00 2.90 1.65 0.00
46.00 2.90 1.65 0.00 150.00 2.90 1.65 0.00
48.00 2.90 1.65 0.00 152.00 2.90 1.65 0.00
50.00 2.90 1.65 0.00 154.00 2.90 1.65 0.00
52.00 2.90 1.65 0.00 156.00 2.90 1.65 0.00
54.00 2.90 1.65 0.00 158.00 2.90 1.65 0.00
56.00 2.90 1.65 0.00 160.00 2.90 1.65 0.00
58.00 2.90 1.65 0.00 162.00 2.90 1.65 0.00
60.00 2.90 1.65 0.00 164.00 2.90 1.65 0.00
62.00 2.90 1.65 0.00 166.00 2.90 1.65 0.00
64.00 2.90 1.65 0.00 168.00 2.90 1.65 0.00
66.00 2.90 1.65 0.00 170.00 2.90 1.65 0.00
68.00 2.90 1.65 0.00 172.00 2.90 1.65 0.00
70.00 2.90 1.65 0.00 174.00 2.90 1.65 0.00
72.00 2.90 1.65 0.00 176.00 2.90 1.65 0.00
74.00 2.90 1.65 0.00 178.00 2.90 1.65 0.00
76.00 2.90 1.65 0.00 180.00 2.90 1.65 0.00
78.00 2.90 1.65 0.00 182.00 2.90 1.65 0.00
80.00 2.90 1.65 0.00 184.00 2.90 1.65 0.00
82.00 2.90 1.65 0.00 186.00 2.90 1.65 0.00
84.00 2.90 1.65 0.00 188.00 2.90 1.65 0.00
86.00 2.90 1.65 0.00 190.00 2.90 1.65 0.00
88.00 2.90 1.65 0.00 192.00 2.90 1.65 0.00
90.00 2.90 1.65 0.00 194.00 2.90 1.65 0.00
92.00 2.90 1.65 0.00 196.00 2.90 1.65 0.00
94.00 2.90 1.65 0.00 198.00 2.90 1.65 0.00
96.00 2.90 1.65 0.00 200.00 2.90 1.65 0.00
98.00 2.90 1.65 0.00
100.00 2.90 1.65 0.00
102.00 2.90 1.65 0.00

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 8
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP6)
Inflow Area = 9.940 ac, Inflow Depth = 1.65" for 1-yr Concord event
Inflow = 30.11 cfs @ 11.96 hrs, Volume= 1.368 af
Outflow = 0.80 cfs @ 14.61 hrs, Volume= 1.368 af, Atten= 97%, Lag= 158.9 min
Primary = 0.80 cfs @ 14.61 hrs, Volume= 1.368 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 620.59' @ 14.61 hrs Surf.Area= 17,227 sf Storage= 38,541 cf
Plug-Flow detention time= 1,354.6 min calculated for 1.368 af(100% of inflow)
Center-of-Mass det. time= 1,354.4 min ( 2,173.5 - 819.1 )
Volume Invert Avail.Storage Storage Description
#1 618.00' 108,921 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
618.00 12,647 0 0
620.00 16,095 28,742 28,742
622.00 19,943 36,038 64,780
624.00 24,198 44,141 108,921
Device Routing Invert Outlet Devices
#1 Primary 596.11' 18.0" x 18.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 596.00' S= 0.0061 '/' Cc= 0.900 n= 0.013
#2 Device 1 618.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.155 0.217 0.279 0.342 0.404 0.466
#3 Device 1 620.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 622.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 623.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=0.80 cfs @ 14.61 hrs HW=620.59' (Free Discharge)
t-1=Culvert (Passes 0.80 cfs of 41.45 cfs potential flow)
2=Exfiltration (Custom Controls 0.25 cfs)
3=Orifice/Grate (Orifice Controls 0.55 cfs @ 2.80 fps)
4=Top of Riser ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=618.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 9
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP6)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 618.00 0.00 0.00 0.00
5.00 0.00 0 618.00 0.00 0.00 0.00
10.00 0.27 962 618.08 0.01 0.01 0.00
15.00 0.74 38,499 620.59 0.80 0.80 0.00
20.00 0.33 34,740 620.36 0.55 0.55 0.00
25.00 0.00 31,398 620.16 0.30 0.30 0.00
30.00 0.00 27,188 619.90 0.21 0.21 0.00
35.00 0.00 23,522 619.67 0.20 0.20 0.00
40.00 0.00 20,109 619.45 0.18 0.18 0.00
45.00 0.00 16,939 619.24 0.17 0.17 0.00
50.00 0.00 14,000 619.03 0.16 0.16 0.00
55.00 0.00 11,383 618.85 0.13 0.13 0.00
60.00 0.00 9,231 618.70 0.11 0.11 0.00
65.00 0.00 7,471 618.57 0.09 0.09 0.00
70.00 0.00 6,037 618.46 0.07 0.07 0.00
75.00 0.00 4,872 618.38 0.06 0.06 0.00
80.00 0.00 3,927 618.30 0.05 0.05 0.00
85.00 0.00 3,162 618.25 0.04 0.04 0.00
90.00 0.00 2,545 618.20 0.03 0.03 0.00
95.00 0.00 2,046 618.16 0.02 0.02 0.00
100.00 0.00 1,645 618.13 0.02 0.02 0.00
105.00 0.00 1,322 618.10 0.02 0.02 0.00
110.00 0.00 1,062 618.08 0.01 0.01 0.00
115.00 0.00 853 618.07 0.01 0.01 0.00
120.00 0.00 684 618.05 0.01 0.01 0.00
125.00 0.00 549 618.04 0.01 0.01 0.00
130.00 0.00 441 618.03 0.01 0.01 0.00
135.00 0.00 354 618.03 0.00 0.00 0.00
140.00 0.00 284 618.02 0.00 0.00 0.00
145.00 0.00 228 618.02 0.00 0.00 0.00
150.00 0.00 183 618.01 0.00 0.00 0.00
155.00 0.00 147 618.01 0.00 0.00 0.00
160.00 0.00 118 618.01 0.00 0.00 0.00
165.00 0.00 95 618.01 0.00 0.00 0.00
170.00 0.00 76 618.01 0.00 0.00 0.00
175.00 0.00 61 618.00 0.00 0.00 0.00
180.00 0.00 49 618.00 0.00 0.00 0.00
185.00 0.00 39 618.00 0.00 0.00 0.00
190.00 0.00 32 618.00 0.00 0.00 0.00
195.00 0.00 25 618.00 0.00 0.00 0.00
200.00 0.00 20 618.00 0.00 0.00 0.00

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 10
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP6)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
618.00 0.00 0.00 0.00 623.20 36.08 33.69 2.40
618.10 0.02 0.02 0.00 623.30 39.43 35.01 4.42
618.20 0.03 0.03 0.00 623.40 43.12 36.29 6.83
618.30 0.05 0.05 0.00 623.50 47.07 37.52 9.55
618.40 0.06 0.06 0.00 623.60 51.26 38.71 12.55
618.50 0.08 0.08 0.00 623.70 55.51 39.87 15.64
618.60 0.09 0.09 0.00 623.80 59.89 40.99 18.89
618.70 0.11 0.11 0.00 623.90 64.59 42.09 22.50
618.80 0.12 0.12 0.00 624.00 69.45 43.15 26.30
618.90 0.14 0.14 0.00
619.00 0.15 0.15 0.00
619.10 0.16 0.16 0.00
619.20 0.17 0.17 0.00
619.30 0.17 0.17 0.00
619.40 0.18 0.18 0.00
619.50 0.19 0.19 0.00
619.60 0.19 0.19 0.00
619.70 0.20 0.20 0.00
619.80 0.20 0.20 0.00
619.90 0.21 0.21 0.00
620.00 0.22 0.22 0.00
620.10 0.25 0.25 0.00
620.20 0.34 0.34 0.00
620.30 0.46 0.46 0.00
620.40 0.60 0.60 0.00
620.50 0.72 0.72 0.00
620.60 0.81 0.81 0.00
620.70 0.89 0.89 0.00
620.80 0.97 0.97 0.00
620.90 1.04 1.04 0.00
621.00 1.10 1.10 0.00
621.10 1.16 1.16 0.00
621.20 1.21 1.21 0.00
621.30 1.27 1.27 0.00
621.40 1.32 1.32 0.00
621.50 1.37 1.37 0.00
621.60 1.42 1.42 0.00
621.70 1.46 1.46 0.00
621.80 1.51 1.51 0.00
621.90 1.55 1.55 0.00
622.00 1.59 1.59 0.00
622.10 2.67 2.67 0.00
622.20 4.60 4.60 0.00
622.30 7.09 7.09 0.00
622.40 10.03 10.03 0.00
622.50 13.35 13.35 0.00
622.60 17.03 17.03 0.00
622.70 21.02 21.02 0.00
622.80 25.30 25.30 0.00
622.90 29.34 29.34 0.00
623.00 30.86 30.86 0.00
623.10 33.15 32.31 0.85

2020.17-BMP6 Type 1124-hr 1-yr Concord Rainfall=2.90"
Prepared by {enter your company name here} Page 11
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP6)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
618.00 12,647 0 623.20 22,496 90,243
618.10 12,819 1,273 623.30 22,709 92,504
618.20 12,992 2,564 623.40 22,921 94,785
618.30 13,164 3,872 623.50 23,134 97,088
618.40 13,337 5,197 623.60 23,347 99,412
618.50 13,509 6,539 623.70 23,560 101,757
618.60 13,681 7,899 623.80 23,772 104,124
618.70 13,854 9,275 623.90 23,985 106,512
618.80 14,026 10,669 624.00 24,198 108,921
618.90 14,199 12,081
619.00 14,371 13,509
619.10 14,543 14,955
619.20 14,716 16,418
619.30 14,888 17,898
619.40 15,061 19,395
619.50 15,233 20,910
619.60 15,405 22,442
619.70 15,578 23,991
619.80 15,750 25,557
619.90 15,923 27,141
620.00 16,095 28,742
620.10 16,287 30,361
620.20 16,480 31,999
620.30 16,672 33,657
620.40 16,865 35,334
620.50 17,057 37,030
620.60 17,249 38,745
620.70 17,442 40,480
620.80 17,634 42,234
620.90 17,827 44,007
621.00 18,019 45,799
621.10 18,211 47,611
621.20 18,404 49,441
621.30 18,596 51,291
621.40 18,789 53,161
621.50 18,981 55,049
621.60 19,173 56,957
621.70 19,366 58,884
621.80 19,558 60,830
621.90 19,751 62,795
622.00 19,943 64,780
622.10 20,156 66,785
622.20 20,369 68,811
622.30 20,581 70,859
622.40 20,794 72,927
622.50 21,007 75,017
622.60 21,220 77,129
622.70 21,432 79,261
622.80 21,645 81,415
622.90 21,858 83,590
623.00 22,071 85,787
623.10 22,283 88,004

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 12
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.940 ac Runoff Depth=2.44"
Flow Length=598' Tc=37.6 min CN=74 Runoff=17.91 cfs 2.025 af
Subcatchment 2S: (Post Developed) Runoff Area=9.940 ac Runoff Depth=3.66"
Tc=5.0 min CN=87 Runoff=64.08 cfs 3.033 af
Pond 3P: (BMP6) Peak Elev=622.36' Storage=72,023 cf Inflow=64.08 cfs 3.033 af
Primary=8.71 cfs 3.032 af Secondary=0.00 cfs 0.000 af Outflow=8.71 cfs 3.032 af
Total Runoff Area = 19.880 ac Runoff Volume = 5.058 af Average Runoff Depth = 3.05"
77.97% Pervious Area = 15.500 ac 22.03% Impervious Area = 4.380 ac

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 13
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 17.91 cfs @ 12.33 hrs, Volume= 2.025 af, Depth= 2.44"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description _
8.510 73 Woods, Fair, HSG C
1.430 79 Pasture/grassland/range, Fair, HSG C
9.940 74 Weighted Average
9.940 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
32.8 100 0.0248 0.05 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.8 498 0.1210 1.74 Shallow Concentrated Flow,
_ Woodland Kv= 5.0 fps _
37.6 598 Total

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 14
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 2.44 0.00
2.00 0.11 0.00 0.00 106.00 5.10 2.44 0.00
4.00 0.24 0.00 0.00 108.00 5.10 2.44 0.00
6.00 0.41 0.00 0.00 110.00 5.10 2.44 0.00
8.00 0.61 0.00 0.00 112.00 5.10 2.44 0.00
10.00 0.92 0.01 0.11 114.00 5.10 2.44 0.00
12.00 3.38 1.16 5.58 116.00 5.10 2.44 0.00
14.00 4.18 1.73 1.91 118.00 5.10 2.44 0.00
16.00 4.49 1.96 1.06 120.00 5.10 2.44 0.00
18.00 4.70 2.13 0.77 122.00 5.10 2.44 0.00
20.00 4.86 2.25 0.58 124.00 5.10 2.44 0.00
22.00 4.98 2.35 0.50 126.00 5.10 2.44 0.00
24.00 5.10 2.44 0.46 128.00 5.10 2.44 0.00
26.00 5.10 2.44 0.00 130.00 5.10 2.44 0.00
28.00 5.10 2.44 0.00 132.00 5.10 2.44 0.00
30.00 5.10 2.44 0.00 134.00 5.10 2.44 0.00
32.00 5.10 2.44 0.00 136.00 5.10 2.44 0.00
34.00 5.10 2.44 0.00 138.00 5.10 2.44 0.00
36.00 5.10 2.44 0.00 140.00 5.10 2.44 0.00
38.00 5.10 2.44 0.00 142.00 5.10 2.44 0.00
40.00 5.10 2.44 0.00 144.00 5.10 2.44 0.00
42.00 5.10 2.44 0.00 146.00 5.10 2.44 0.00
44.00 5.10 2.44 0.00 148.00 5.10 2.44 0.00
46.00 5.10 2.44 0.00 150.00 5.10 2.44 0.00
48.00 5.10 2.44 0.00 152.00 5.10 2.44 0.00
50.00 5.10 2.44 0.00 154.00 5.10 2.44 0.00
52.00 5.10 2.44 0.00 156.00 5.10 2.44 0.00
54.00 5.10 2.44 0.00 158.00 5.10 2.44 0.00
56.00 5.10 2.44 0.00 160.00 5.10 2.44 0.00
58.00 5.10 2.44 0.00 162.00 5.10 2.44 0.00
60.00 5.10 2.44 0.00 164.00 5.10 2.44 0.00
62.00 5.10 2.44 0.00 166.00 5.10 2.44 0.00
64.00 5.10 2.44 0.00 168.00 5.10 2.44 0.00
66.00 5.10 2.44 0.00 170.00 5.10 2.44 0.00
68.00 5.10 2.44 0.00 172.00 5.10 2.44 0.00
70.00 5.10 2.44 0.00 174.00 5.10 2.44 0.00
72.00 5.10 2.44 0.00 176.00 5.10 2.44 0.00
74.00 5.10 2.44 0.00 178.00 5.10 2.44 0.00
76.00 5.10 2.44 0.00 180.00 5.10 2.44 0.00
78.00 5.10 2.44 0.00 182.00 5.10 2.44 0.00
80.00 5.10 2.44 0.00 184.00 5.10 2.44 0.00
82.00 5.10 2.44 0.00 186.00 5.10 2.44 0.00
84.00 5.10 2.44 0.00 188.00 5.10 2.44 0.00
86.00 5.10 2.44 0.00 190.00 5.10 2.44 0.00
88.00 5.10 2.44 0.00 192.00 5.10 2.44 0.00
90.00 5.10 2.44 0.00 194.00 5.10 2.44 0.00
92.00 5.10 2.44 0.00 196.00 5.10 2.44 0.00
94.00 5.10 2.44 0.00 198.00 5.10 2.44 0.00
96.00 5.10 2.44 0.00 200.00 5.10 2.44 0.00
98.00 5.10 2.44 0.00
100.00 5.10 2.44 0.00
102.00 5.10 2.44 0.00

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 15
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 64.08 cfs @ 11.96 hrs, Volume= 3.033 af, Depth= 3.66"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 10-yr Concord Rainfall=5.10"
Area (ac) CN Description
4.380 98 Paved parking & roofs
5.560 79 50-75% Grass cover, Fair, HSG C
9.940 87 Weighted Average
5.560 Pervious Area
4.380 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 16
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 5.10 3.66 0.00
2.00 0.11 0.00 0.00 106.00 5.10 3.66 0.00
4.00 0.24 0.00 0.00 108.00 5.10 3.66 0.00
6.00 0.41 0.01 0.11 110.00 5.10 3.66 0.00
8.00 0.61 0.05 0.35 112.00 5.10 3.66 0.00
10.00 0.92 0.18 0.98 114.00 5.10 3.66 0.00
12.00 3.38 2.08 53.83 116.00 5.10 3.66 0.00
14.00 4.18 2.80 1.82 118.00 5.10 3.66 0.00
16.00 4.49 3.09 1.12 120.00 5.10 3.66 0.00
18.00 4.70 3.28 0.87 122.00 5.10 3.66 0.00
20.00 4.86 3.43 0.63 124.00 5.10 3.66 0.00
22.00 4.98 3.55 0.58 126.00 5.10 3.66 0.00
24.00 5.10 3.66 0.53 128.00 5.10 3.66 0.00
26.00 5.10 3.66 0.00 130.00 5.10 3.66 0.00
28.00 5.10 3.66 0.00 132.00 5.10 3.66 0.00
30.00 5.10 3.66 0.00 134.00 5.10 3.66 0.00
32.00 5.10 3.66 0.00 136.00 5.10 3.66 0.00
34.00 5.10 3.66 0.00 138.00 5.10 3.66 0.00
36.00 5.10 3.66 0.00 140.00 5.10 3.66 0.00
38.00 5.10 3.66 0.00 142.00 5.10 3.66 0.00
40.00 5.10 3.66 0.00 144.00 5.10 3.66 0.00
42.00 5.10 3.66 0.00 146.00 5.10 3.66 0.00
44.00 5.10 3.66 0.00 148.00 5.10 3.66 0.00
46.00 5.10 3.66 0.00 150.00 5.10 3.66 0.00
48.00 5.10 3.66 0.00 152.00 5.10 3.66 0.00
50.00 5.10 3.66 0.00 154.00 5.10 3.66 0.00
52.00 5.10 3.66 0.00 156.00 5.10 3.66 0.00
54.00 5.10 3.66 0.00 158.00 5.10 3.66 0.00
56.00 5.10 3.66 0.00 160.00 5.10 3.66 0.00
58.00 5.10 3.66 0.00 162.00 5.10 3.66 0.00
60.00 5.10 3.66 0.00 164.00 5.10 3.66 0.00
62.00 5.10 3.66 0.00 166.00 5.10 3.66 0.00
64.00 5.10 3.66 0.00 168.00 5.10 3.66 0.00
66.00 5.10 3.66 0.00 170.00 5.10 3.66 0.00
68.00 5.10 3.66 0.00 172.00 5.10 3.66 0.00
70.00 5.10 3.66 0.00 174.00 5.10 3.66 0.00
72.00 5.10 3.66 0.00 176.00 5.10 3.66 0.00
74.00 5.10 3.66 0.00 178.00 5.10 3.66 0.00
76.00 5.10 3.66 0.00 180.00 5.10 3.66 0.00
78.00 5.10 3.66 0.00 182.00 5.10 3.66 0.00
80.00 5.10 3.66 0.00 184.00 5.10 3.66 0.00
82.00 5.10 3.66 0.00 186.00 5.10 3.66 0.00
84.00 5.10 3.66 0.00 188.00 5.10 3.66 0.00
86.00 5.10 3.66 0.00 190.00 5.10 3.66 0.00
88.00 5.10 3.66 0.00 192.00 5.10 3.66 0.00
90.00 5.10 3.66 0.00 194.00 5.10 3.66 0.00
92.00 5.10 3.66 0.00 196.00 5.10 3.66 0.00
94.00 5.10 3.66 0.00 198.00 5.10 3.66 0.00
96.00 5.10 3.66 0.00 200.00 5.10 3.66 0.00
98.00 5.10 3.66 0.00
100.00 5.10 3.66 0.00
102.00 5.10 3.66 0.00

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 17
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP6)
Inflow Area = 9.940 ac, Inflow Depth = 3.66" for 10-yr Concord event
Inflow = 64.08 cfs @ 11.96 hrs, Volume= 3.033 af
Outflow = 8.71 cfs @ 12.17 hrs, Volume= 3.032 af, Atten= 86%, Lag= 12.8 min
Primary = 8.71 cfs @ 12.17 hrs, Volume= 3.032 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 622.36' @ 12.17 hrs Surf.Area= 20,701 sf Storage= 72,023 cf
Plug-Flow detention time= 836.4 min calculated for 3.032 af(100% of inflow)
Center-of-Mass det. time= 836.3 min ( 1,632.7 - 796.4 )
Volume Invert Avail.Storage Storage Description
#1 618.00' 108,921 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
618.00 12,647 0 0
620.00 16,095 28,742 28,742
622.00 19,943 36,038 64,780
624.00 24,198 44,141 108,921
Device Routing Invert Outlet Devices
#1 Primary 596.11' 18.0" x 18.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 596.00' S= 0.0061 'I' Cc= 0.900 n= 0.013
#2 Device 1 618.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.155 0.217 0.279 0.342 0.404 0.466
#3 Device 1 620.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 622.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 623.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=8.69 cfs @ 12.17 hrs HW=622.36' (Free Discharge)
t-1=Culvert (Passes 8.69 cfs of 42.96 cfs potential flow)
2=Exfiltration (Custom Controls 0.36 cfs)
3=Orifice/Grate (Orifice Controls 1.37 cfs @ 6.99 fps)
4=Top of Riser (Weir Controls 6.96 cfs @ 1.95 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=618.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 18
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP6)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 618.00 0.00 0.00 0.00
5.00 0.02 6 618.00 0.00 0.00 0.00
10.00 0.98 5,971 618.46 0.07 0.07 0.00
15.00 1.45 65,096 622.02 1.67 1.67 0.00
20.00 0.63 55,123 621.50 1.37 1.37 0.00
25.00 0.00 42,153 620.80 0.96 0.96 0.00
30.00 0.00 31,336 620.16 0.30 0.30 0.00
35.00 0.00 27,145 619.90 0.21 0.21 0.00
40.00 0.00 23,482 619.67 0.20 0.20 0.00
45.00 0.00 20,072 619.44 0.18 0.18 0.00
50.00 0.00 16,905 619.23 0.17 0.17 0.00
55.00 0.00 13,968 619.03 0.16 0.16 0.00
60.00 0.00 11,356 618.85 0.13 0.13 0.00
65.00 0.00 9,209 618.70 0.11 0.11 0.00
70.00 0.00 7,453 618.57 0.09 0.09 0.00
75.00 0.00 6,022 618.46 0.07 0.07 0.00
80.00 0.00 4,860 618.37 0.06 0.06 0.00
85.00 0.00 3,917 618.30 0.05 0.05 0.00
90.00 0.00 3,154 618.25 0.04 0.04 0.00
95.00 0.00 2,538 618.20 0.03 0.03 0.00
100.00 0.00 2,041 618.16 0.02 0.02 0.00
105.00 0.00 1,641 618.13 0.02 0.02 0.00
110.00 0.00 1,318 618.10 0.02 0.02 0.00
115.00 0.00 1,059 618.08 0.01 0.01 0.00
120.00 0.00 850 618.07 0.01 0.01 0.00
125.00 0.00 683 618.05 0.01 0.01 0.00
130.00 0.00 548 618.04 0.01 0.01 0.00
135.00 0.00 440 618.03 0.01 0.01 0.00
140.00 0.00 353 618.03 0.00 0.00 0.00
145.00 0.00 284 618.02 0.00 0.00 0.00
150.00 0.00 228 618.02 0.00 0.00 0.00
155.00 0.00 183 618.01 0.00 0.00 0.00
160.00 0.00 147 618.01 0.00 0.00 0.00
165.00 0.00 118 618.01 0.00 0.00 0.00
170.00 0.00 95 618.01 0.00 0.00 0.00
175.00 0.00 76 618.01 0.00 0.00 0.00
180.00 0.00 61 618.00 0.00 0.00 0.00
185.00 0.00 49 618.00 0.00 0.00 0.00
190.00 0.00 39 618.00 0.00 0.00 0.00
195.00 0.00 32 618.00 0.00 0.00 0.00
200.00 0.00 25 618.00 0.00 0.00 0.00

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 19
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP6)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
618.00 0.00 0.00 0.00 623.20 36.08 33.69 2.40
618.10 0.02 0.02 0.00 623.30 39.43 35.01 4.42
618.20 0.03 0.03 0.00 623.40 43.12 36.29 6.83
618.30 0.05 0.05 0.00 623.50 47.07 37.52 9.55
618.40 0.06 0.06 0.00 623.60 51.26 38.71 12.55
618.50 0.08 0.08 0.00 623.70 55.51 39.87 15.64
618.60 0.09 0.09 0.00 623.80 59.89 40.99 18.89
618.70 0.11 0.11 0.00 623.90 64.59 42.09 22.50
618.80 0.12 0.12 0.00 624.00 69.45 43.15 26.30
618.90 0.14 0.14 0.00
619.00 0.15 0.15 0.00
619.10 0.16 0.16 0.00
619.20 0.17 0.17 0.00
619.30 0.17 0.17 0.00
619.40 0.18 0.18 0.00
619.50 0.19 0.19 0.00
619.60 0.19 0.19 0.00
619.70 0.20 0.20 0.00
619.80 0.20 0.20 0.00
619.90 0.21 0.21 0.00
620.00 0.22 0.22 0.00
620.10 0.25 0.25 0.00
620.20 0.34 0.34 0.00
620.30 0.46 0.46 0.00
620.40 0.60 0.60 0.00
620.50 0.72 0.72 0.00
620.60 0.81 0.81 0.00
620.70 0.89 0.89 0.00
620.80 0.97 0.97 0.00
620.90 1.04 1.04 0.00
621.00 1.10 1.10 0.00
621.10 1.16 1.16 0.00
621.20 1.21 1.21 0.00
621.30 1.27 1.27 0.00
621.40 1.32 1.32 0.00
621.50 1.37 1.37 0.00
621.60 1.42 1.42 0.00
621.70 1.46 1.46 0.00
621.80 1.51 1.51 0.00
621.90 1.55 1.55 0.00
622.00 1.59 1.59 0.00
622.10 2.67 2.67 0.00
622.20 4.60 4.60 0.00
622.30 7.09 7.09 0.00
622.40 10.03 10.03 0.00
622.50 13.35 13.35 0.00
622.60 17.03 17.03 0.00
622.70 21.02 21.02 0.00
622.80 25.30 25.30 0.00
622.90 29.34 29.34 0.00
623.00 30.86 30.86 0.00
623.10 33.15 32.31 0.85

2020.17-BMP6 Type 1124-hr 10-yr Concord Rainfall=5.10"
Prepared by {enter your company name here} Page 20
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP6)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
618.00 12,647 0 623.20 22,496 90,243
618.10 12,819 1,273 623.30 22,709 92,504
618.20 12,992 2,564 623.40 22,921 94,785
618.30 13,164 3,872 623.50 23,134 97,088
618.40 13,337 5,197 623.60 23,347 99,412
618.50 13,509 6,539 623.70 23,560 101,757
618.60 13,681 7,899 623.80 23,772 104,124
618.70 13,854 9,275 623.90 23,985 106,512
618.80 14,026 10,669 624.00 24,198 108,921
618.90 14,199 12,081
619.00 14,371 13,509
619.10 14,543 14,955
619.20 14,716 16,418
619.30 14,888 17,898
619.40 15,061 19,395
619.50 15,233 20,910
619.60 15,405 22,442
619.70 15,578 23,991
619.80 15,750 25,557
619.90 15,923 27,141
620.00 16,095 28,742
620.10 16,287 30,361
620.20 16,480 31,999
620.30 16,672 33,657
620.40 16,865 35,334
620.50 17,057 37,030
620.60 17,249 38,745
620.70 17,442 40,480
620.80 17,634 42,234
620.90 17,827 44,007
621.00 18,019 45,799
621.10 18,211 47,611
621.20 18,404 49,441
621.30 18,596 51,291
621.40 18,789 53,161
621.50 18,981 55,049
621.60 19,173 56,957
621.70 19,366 58,884
621.80 19,558 60,830
621.90 19,751 62,795
622.00 19,943 64,780
622.10 20,156 66,785
622.20 20,369 68,811
622.30 20,581 70,859
622.40 20,794 72,927
622.50 21,007 75,017
622.60 21,220 77,129
622.70 21,432 79,261
622.80 21,645 81,415
622.90 21,858 83,590
623.00 22,071 85,787
623.10 22,283 88,004

2020.17-BMP6 Type 11 24-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 21
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.940 ac Runoff Depth=3.18"
Flow Length=598' Tc=37.6 min CN=74 Runoff=23.55 cfs 2.638 af
Subcatchment 2S: (Post Developed) Runoff Area=9.940 ac Runoff Depth=4.52"
Tc=5.0 min CN=87 Runoff=78.00 cfs 3.742 af
Pond 3P: (BMP6) Peak Elev=622.84' Storage=82,360 cf Inflow=78.00 cfs 3.742 af
Primary=27.26 cfs 3.741 af Secondary=0.00 cfs 0.000 af Outflow=27.26 cfs 3.741 af
Total Runoff Area = 19.880 ac Runoff Volume = 6.380 af Average Runoff Depth = 3.85"
77.97% Pervious Area = 15.500 ac 22.03% Impervious Area = 4.380 ac

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 22
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 23.55 cfs @ 12.33 hrs, Volume= 2.638 af, Depth= 3.18"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
8.510 73 Woods, Fair, HSG C
1.430 79 Pasture/grassland/range, Fair, HSG C
9.940 74 Weighted Average
9.940 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
32.8 100 0.0248 0.05 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.8 498 0.1210 1.74 Shallow Concentrated Flow,
_ Woodland Kv= 5.0 fps _
37.6 598 Total

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 23
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 3.18 0.00
2.00 0.13 0.00 0.00 106.00 6.00 3.18 0.00
4.00 0.29 0.00 0.00 108.00 6.00 3.18 0.00
6.00 0.48 0.00 0.00 110.00 6.00 3.18 0.00
8.00 0.72 0.00 0.00 112.00 6.00 3.18 0.00
10.00 1.09 0.04 0.26 114.00 6.00 3.18 0.00
12.00 3.98 1.58 7.74 116.00 6.00 3.18 0.00
14.00 4.92 2.30 2.40 118.00 6.00 3.18 0.00
16.00 5.28 2.59 1.31 120.00 6.00 3.18 0.00
18.00 5.53 2.79 0.96 122.00 6.00 3.18 0.00
20.00 5.71 2.94 0.72 124.00 6.00 3.18 0.00
22.00 5.86 3.07 0.62 126.00 6.00 3.18 0.00
24.00 6.00 3.18 0.57 128.00 6.00 3.18 0.00
26.00 6.00 3.18 0.00 130.00 6.00 3.18 0.00
28.00 6.00 3.18 0.00 132.00 6.00 3.18 0.00
30.00 6.00 3.18 0.00 134.00 6.00 3.18 0.00
32.00 6.00 3.18 0.00 136.00 6.00 3.18 0.00
34.00 6.00 3.18 0.00 138.00 6.00 3.18 0.00
36.00 6.00 3.18 0.00 140.00 6.00 3.18 0.00
38.00 6.00 3.18 0.00 142.00 6.00 3.18 0.00
40.00 6.00 3.18 0.00 144.00 6.00 3.18 0.00
42.00 6.00 3.18 0.00 146.00 6.00 3.18 0.00
44.00 6.00 3.18 0.00 148.00 6.00 3.18 0.00
46.00 6.00 3.18 0.00 150.00 6.00 3.18 0.00
48.00 6.00 3.18 0.00 152.00 6.00 3.18 0.00
50.00 6.00 3.18 0.00 154.00 6.00 3.18 0.00
52.00 6.00 3.18 0.00 156.00 6.00 3.18 0.00
54.00 6.00 3.18 0.00 158.00 6.00 3.18 0.00
56.00 6.00 3.18 0.00 160.00 6.00 3.18 0.00
58.00 6.00 3.18 0.00 162.00 6.00 3.18 0.00
60.00 6.00 3.18 0.00 164.00 6.00 3.18 0.00
62.00 6.00 3.18 0.00 166.00 6.00 3.18 0.00
64.00 6.00 3.18 0.00 168.00 6.00 3.18 0.00
66.00 6.00 3.18 0.00 170.00 6.00 3.18 0.00
68.00 6.00 3.18 0.00 172.00 6.00 3.18 0.00
70.00 6.00 3.18 0.00 174.00 6.00 3.18 0.00
72.00 6.00 3.18 0.00 176.00 6.00 3.18 0.00
74.00 6.00 3.18 0.00 178.00 6.00 3.18 0.00
76.00 6.00 3.18 0.00 180.00 6.00 3.18 0.00
78.00 6.00 3.18 0.00 182.00 6.00 3.18 0.00
80.00 6.00 3.18 0.00 184.00 6.00 3.18 0.00
82.00 6.00 3.18 0.00 186.00 6.00 3.18 0.00
84.00 6.00 3.18 0.00 188.00 6.00 3.18 0.00
86.00 6.00 3.18 0.00 190.00 6.00 3.18 0.00
88.00 6.00 3.18 0.00 192.00 6.00 3.18 0.00
90.00 6.00 3.18 0.00 194.00 6.00 3.18 0.00
92.00 6.00 3.18 0.00 196.00 6.00 3.18 0.00
94.00 6.00 3.18 0.00 198.00 6.00 3.18 0.00
96.00 6.00 3.18 0.00 200.00 6.00 3.18 0.00
98.00 6.00 3.18 0.00
100.00 6.00 3.18 0.00
102.00 6.00 3.18 0.00

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 24
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 78.00 cfs @ 11.96 hrs, Volume= 3.742 af, Depth= 4.52"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 25-yr Concord Rainfall=6.00"
Area (ac) CN Description
4.380 98 Paved parking & roofs
5.560 79 50-75% Grass cover, Fair, HSG C
9.940 87 Weighted Average
5.560 Pervious Area
4.380 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs) _
5.0 Direct Entry,

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 25
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.00 4.52 0.00
2.00 0.13 0.00 0.00 106.00 6.00 4.52 0.00
4.00 0.29 0.00 0.00 108.00 6.00 4.52 0.00
6.00 0.48 0.02 0.21 110.00 6.00 4.52 0.00
8.00 0.72 0.09 0.51 112.00 6.00 4.52 0.00
10.00 1.09 0.27 1.31 114.00 6.00 4.52 0.00
12.00 3.98 2.62 65.29 116.00 6.00 4.52 0.00
14.00 4.92 3.49 2.18 118.00 6.00 4.52 0.00
16.00 5.28 3.83 1.34 120.00 6.00 4.52 0.00
18.00 5.53 4.07 1.04 122.00 6.00 4.52 0.00
20.00 5.71 4.24 0.76 124.00 6.00 4.52 0.00
22.00 5.86 4.39 0.69 126.00 6.00 4.52 0.00
24.00 6.00 4.52 0.64 128.00 6.00 4.52 0.00
26.00 6.00 4.52 0.00 130.00 6.00 4.52 0.00
28.00 6.00 4.52 0.00 132.00 6.00 4.52 0.00
30.00 6.00 4.52 0.00 134.00 6.00 4.52 0.00
32.00 6.00 4.52 0.00 136.00 6.00 4.52 0.00
34.00 6.00 4.52 0.00 138.00 6.00 4.52 0.00
36.00 6.00 4.52 0.00 140.00 6.00 4.52 0.00
38.00 6.00 4.52 0.00 142.00 6.00 4.52 0.00
40.00 6.00 4.52 0.00 144.00 6.00 4.52 0.00
42.00 6.00 4.52 0.00 146.00 6.00 4.52 0.00
44.00 6.00 4.52 0.00 148.00 6.00 4.52 0.00
46.00 6.00 4.52 0.00 150.00 6.00 4.52 0.00
48.00 6.00 4.52 0.00 152.00 6.00 4.52 0.00
50.00 6.00 4.52 0.00 154.00 6.00 4.52 0.00
52.00 6.00 4.52 0.00 156.00 6.00 4.52 0.00
54.00 6.00 4.52 0.00 158.00 6.00 4.52 0.00
56.00 6.00 4.52 0.00 160.00 6.00 4.52 0.00
58.00 6.00 4.52 0.00 162.00 6.00 4.52 0.00
60.00 6.00 4.52 0.00 164.00 6.00 4.52 0.00
62.00 6.00 4.52 0.00 166.00 6.00 4.52 0.00
64.00 6.00 4.52 0.00 168.00 6.00 4.52 0.00
66.00 6.00 4.52 0.00 170.00 6.00 4.52 0.00
68.00 6.00 4.52 0.00 172.00 6.00 4.52 0.00
70.00 6.00 4.52 0.00 174.00 6.00 4.52 0.00
72.00 6.00 4.52 0.00 176.00 6.00 4.52 0.00
74.00 6.00 4.52 0.00 178.00 6.00 4.52 0.00
76.00 6.00 4.52 0.00 180.00 6.00 4.52 0.00
78.00 6.00 4.52 0.00 182.00 6.00 4.52 0.00
80.00 6.00 4.52 0.00 184.00 6.00 4.52 0.00
82.00 6.00 4.52 0.00 186.00 6.00 4.52 0.00
84.00 6.00 4.52 0.00 188.00 6.00 4.52 0.00
86.00 6.00 4.52 0.00 190.00 6.00 4.52 0.00
88.00 6.00 4.52 0.00 192.00 6.00 4.52 0.00
90.00 6.00 4.52 0.00 194.00 6.00 4.52 0.00
92.00 6.00 4.52 0.00 196.00 6.00 4.52 0.00
94.00 6.00 4.52 0.00 198.00 6.00 4.52 0.00
96.00 6.00 4.52 0.00 200.00 6.00 4.52 0.00
98.00 6.00 4.52 0.00
100.00 6.00 4.52 0.00
102.00 6.00 4.52 0.00

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 26
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP6)
Inflow Area = 9.940 ac, Inflow Depth = 4.52" for 25-yr Concord event
Inflow = 78.00 cfs @ 11.96 hrs, Volume= 3.742 af
Outflow = 27.26 cfs @ 12.06 hrs, Volume= 3.741 af, Atten= 65%, Lag= 6.3 min
Primary = 27.26 cfs @ 12.06 hrs, Volume= 3.741 af
Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 622.84' @ 12.06 hrs Surf.Area= 21,738 sf Storage= 82,360 cf
Plug-Flow detention time= 706.4 min calculated for 3.741 af(100% of inflow)
Center-of-Mass det. time= 706.3 min ( 1,496.8 - 790.5 )
Volume Invert Avail.Storage Storage Description _
#1 618.00' 108,921 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
618.00 12,647 0 0
620.00 16,095 28,742 28,742
622.00 19,943 36,038 64,780
624.00 24,198 44,141 108,921
Device Routing Invert Outlet Devices
#1 Primary 596.11' 18.0" x 18.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 596.00' S= 0.0061 'I' Cc= 0.900 n= 0.013
#2 Device 1 618.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.155 0.217 0.279 0.342 0.404 0.466
#3 Device 1 620.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 622.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 623.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=27.21 cfs @ 12.06 hrs HW=622.84' (Free Discharge)
t-1=Culvert (Passes 27.21 cfs of 43.37 cfs potential flow)
2=Exfiltration (Custom Controls 0.39 cfs)
3=Orifice/Grate (Orifice Controls 1.52 cfs @ 7.75 fps)
4=Top of Riser (Weir Controls 25.29 cfs @ 3.00 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=618.00' (Free Discharge)
t-5=Spillway ( Controls 0.00 cfs)

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 27
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP6)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 618.00 0.00 0.00 0.00
5.00 0.09 118 618.01 0.00 0.00 0.00
10.00 1.31 8,794 618.67 0.10 0.10 0.00
15.00 1.73 65,645 622.04 1.95 1.95 0.00
20.00 0.76 57,818 621.64 1.44 1.44 0.00
25.00 0.00 44,923 620.95 1.07 1.07 0.00
30.00 0.00 32,230 620.21 0.36 0.36 0.00
35.00 0.00 27,723 619.94 0.21 0.21 0.00
40.00 0.00 24,020 619.70 0.20 0.20 0.00
45.00 0.00 20,572 619.48 0.18 0.18 0.00
50.00 0.00 17,369 619.26 0.17 0.17 0.00
55.00 0.00 14,398 619.06 0.16 0.16 0.00
60.00 0.00 11,720 618.87 0.14 0.14 0.00
65.00 0.00 9,507 618.72 0.11 0.11 0.00
70.00 0.00 7,696 618.59 0.09 0.09 0.00
75.00 0.00 6,220 618.48 0.07 0.07 0.00
80.00 0.00 5,021 618.39 0.06 0.06 0.00
85.00 0.00 4,047 618.31 0.05 0.05 0.00
90.00 0.00 3,260 618.25 0.04 0.04 0.00
95.00 0.00 2,623 618.20 0.03 0.03 0.00
100.00 0.00 2,110 618.16 0.03 0.03 0.00
105.00 0.00 1,696 618.13 0.02 0.02 0.00
110.00 0.00 1,363 618.11 0.02 0.02 0.00
115.00 0.00 1,095 618.09 0.01 0.01 0.00
120.00 0.00 879 618.07 0.01 0.01 0.00
125.00 0.00 706 618.06 0.01 0.01 0.00
130.00 0.00 567 618.04 0.01 0.01 0.00
135.00 0.00 455 618.04 0.01 0.01 0.00
140.00 0.00 365 618.03 0.00 0.00 0.00
145.00 0.00 293 618.02 0.00 0.00 0.00
150.00 0.00 235 618.02 0.00 0.00 0.00
155.00 0.00 189 618.01 0.00 0.00 0.00
160.00 0.00 152 618.01 0.00 0.00 0.00
165.00 0.00 122 618.01 0.00 0.00 0.00
170.00 0.00 98 618.01 0.00 0.00 0.00
175.00 0.00 78 618.01 0.00 0.00 0.00
180.00 0.00 63 618.00 0.00 0.00 0.00
185.00 0.00 51 618.00 0.00 0.00 0.00
190.00 0.00 41 618.00 0.00 0.00 0.00
195.00 0.00 33 618.00 0.00 0.00 0.00
200.00 0.00 26 618.00 0.00 0.00 0.00

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 28
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP6)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
618.00 0.00 0.00 0.00 623.20 36.08 33.69 2.40
618.10 0.02 0.02 0.00 623.30 39.43 35.01 4.42
618.20 0.03 0.03 0.00 623.40 43.12 36.29 6.83
618.30 0.05 0.05 0.00 623.50 47.07 37.52 9.55
618.40 0.06 0.06 0.00 623.60 51.26 38.71 12.55
618.50 0.08 0.08 0.00 623.70 55.51 39.87 15.64
618.60 0.09 0.09 0.00 623.80 59.89 40.99 18.89
618.70 0.11 0.11 0.00 623.90 64.59 42.09 22.50
618.80 0.12 0.12 0.00 624.00 69.45 43.15 26.30
618.90 0.14 0.14 0.00
619.00 0.15 0.15 0.00
619.10 0.16 0.16 0.00
619.20 0.17 0.17 0.00
619.30 0.17 0.17 0.00
619.40 0.18 0.18 0.00
619.50 0.19 0.19 0.00
619.60 0.19 0.19 0.00
619.70 0.20 0.20 0.00
619.80 0.20 0.20 0.00
619.90 0.21 0.21 0.00
620.00 0.22 0.22 0.00
620.10 0.25 0.25 0.00
620.20 0.34 0.34 0.00
620.30 0.46 0.46 0.00
620.40 0.60 0.60 0.00
620.50 0.72 0.72 0.00
620.60 0.81 0.81 0.00
620.70 0.89 0.89 0.00
620.80 0.97 0.97 0.00
620.90 1.04 1.04 0.00
621.00 1.10 1.10 0.00
621.10 1.16 1.16 0.00
621.20 1.21 1.21 0.00
621.30 1.27 1.27 0.00
621.40 1.32 1.32 0.00
621.50 1.37 1.37 0.00
621.60 1.42 1.42 0.00
621.70 1.46 1.46 0.00
621.80 1.51 1.51 0.00
621.90 1.55 1.55 0.00
622.00 1.59 1.59 0.00
622.10 2.67 2.67 0.00
622.20 4.60 4.60 0.00
622.30 7.09 7.09 0.00
622.40 10.03 10.03 0.00
622.50 13.35 13.35 0.00
622.60 17.03 17.03 0.00
622.70 21.02 21.02 0.00
622.80 25.30 25.30 0.00
622.90 29.34 29.34 0.00
623.00 30.86 30.86 0.00
623.10 33.15 32.31 0.85

2020.17-BMP6 Type 1124-hr 25-yr Concord Rainfall=6.00"
Prepared by {enter your company name here} Page 29
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP6)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
618.00 12,647 0 623.20 22,496 90,243
618.10 12,819 1,273 623.30 22,709 92,504
618.20 12,992 2,564 623.40 22,921 94,785
618.30 13,164 3,872 623.50 23,134 97,088
618.40 13,337 5,197 623.60 23,347 99,412
618.50 13,509 6,539 623.70 23,560 101,757
618.60 13,681 7,899 623.80 23,772 104,124
618.70 13,854 9,275 623.90 23,985 106,512
618.80 14,026 10,669 624.00 24,198 108,921
618.90 14,199 12,081
619.00 14,371 13,509
619.10 14,543 14,955
619.20 14,716 16,418
619.30 14,888 17,898
619.40 15,061 19,395
619.50 15,233 20,910
619.60 15,405 22,442
619.70 15,578 23,991
619.80 15,750 25,557
619.90 15,923 27,141
620.00 16,095 28,742
620.10 16,287 30,361
620.20 16,480 31,999
620.30 16,672 33,657
620.40 16,865 35,334
620.50 17,057 37,030
620.60 17,249 38,745
620.70 17,442 40,480
620.80 17,634 42,234
620.90 17,827 44,007
621.00 18,019 45,799
621.10 18,211 47,611
621.20 18,404 49,441
621.30 18,596 51,291
621.40 18,789 53,161
621.50 18,981 55,049
621.60 19,173 56,957
621.70 19,366 58,884
621.80 19,558 60,830
621.90 19,751 62,795
622.00 19,943 64,780
622.10 20,156 66,785
622.20 20,369 68,811
622.30 20,581 70,859
622.40 20,794 72,927
622.50 21,007 75,017
622.60 21,220 77,129
622.70 21,432 79,261
622.80 21,645 81,415
622.90 21,858 83,590
623.00 22,071 85,787
623.10 22,283 88,004

2020.17-BMP6 Type II 24-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 30
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Time span=0.00-200.00 hrs, dt=0.01 hrs, 20001 points
Runoff by SCS TR-20 method, UH=SCS
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: (Predeveloped) Runoff Area=9.940 ac Runoff Depth=3.87"
Flow Length=598' Tc=37.6 min CN=74 Runoff=28.71 cfs 3.204 af
Subcatchment 2S: (Post Developed) Runoff Area=9.940 ac Runoff Depth=5.29"
Tc=5.0 min CN=87 Runoff=90.33 cfs 4.379 af
Pond 3P: (BMP6) Peak Elev=623.27' Storage=91,796 cf Inflow=90.33 cfs 4.379 af
Primary=34.60 cfs 4.349 af Secondary=3.76 cfs 0.029 af Outflow=38.36 cfs 4.378 af
Total Runoff Area = 19.880 ac Runoff Volume = 7.583 af Average Runoff Depth = 4.58"
77.97% Pervious Area = 15.500 ac 22.03% Impervious Area = 4.380 ac

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 31
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 1 S: (Predeveloped)
BASED ON EXISTING CONDITIONS
Runoff = 28.71 cfs @ 12.33 hrs, Volume= 3.204 af, Depth= 3.87"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
8.510 73 Woods, Fair, HSG C
1.430 79 Pasture/grassland/range, Fair, HSG C
9.940 74 Weighted Average
9.940 Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
32.8 100 0.0248 0.05 Sheet Flow,
Woods: Dense underbrush n= 0.800 P2= 3.50"
4.8 498 0.1210 1.74 Shallow Concentrated Flow,
_ Woodland Kv= 5.0 fps _
37.6 598 Total

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 32
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 1S: (Predeveloped)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 3.87 0.00
2.00 0.15 0.00 0.00 106.00 6.80 3.87 0.00
4.00 0.33 0.00 0.00 108.00 6.80 3.87 0.00
6.00 0.54 0.00 0.00 110.00 6.80 3.87 0.00
8.00 0.82 0.00 0.03 112.00 6.80 3.87 0.00
10.00 1.23 0.07 0.43 114.00 6.80 3.87 0.00
12.00 4.51 1.98 9.76 116.00 6.80 3.87 0.00
14.00 5.58 2.83 2.83 118.00 6.80 3.87 0.00
16.00 5.98 3.17 1.54 120.00 6.80 3.87 0.00
18.00 6.26 3.41 1.12 122.00 6.80 3.87 0.00
20.00 6.47 3.59 0.84 124.00 6.80 3.87 0.00
22.00 6.64 3.73 0.72 126.00 6.80 3.87 0.00
24.00 6.80 3.87 0.67 128.00 6.80 3.87 0.00
26.00 6.80 3.87 0.00 130.00 6.80 3.87 0.00
28.00 6.80 3.87 0.00 132.00 6.80 3.87 0.00
30.00 6.80 3.87 0.00 134.00 6.80 3.87 0.00
32.00 6.80 3.87 0.00 136.00 6.80 3.87 0.00
34.00 6.80 3.87 0.00 138.00 6.80 3.87 0.00
36.00 6.80 3.87 0.00 140.00 6.80 3.87 0.00
38.00 6.80 3.87 0.00 142.00 6.80 3.87 0.00
40.00 6.80 3.87 0.00 144.00 6.80 3.87 0.00
42.00 6.80 3.87 0.00 146.00 6.80 3.87 0.00
44.00 6.80 3.87 0.00 148.00 6.80 3.87 0.00
46.00 6.80 3.87 0.00 150.00 6.80 3.87 0.00
48.00 6.80 3.87 0.00 152.00 6.80 3.87 0.00
50.00 6.80 3.87 0.00 154.00 6.80 3.87 0.00
52.00 6.80 3.87 0.00 156.00 6.80 3.87 0.00
54.00 6.80 3.87 0.00 158.00 6.80 3.87 0.00
56.00 6.80 3.87 0.00 160.00 6.80 3.87 0.00
58.00 6.80 3.87 0.00 162.00 6.80 3.87 0.00
60.00 6.80 3.87 0.00 164.00 6.80 3.87 0.00
62.00 6.80 3.87 0.00 166.00 6.80 3.87 0.00
64.00 6.80 3.87 0.00 168.00 6.80 3.87 0.00
66.00 6.80 3.87 0.00 170.00 6.80 3.87 0.00
68.00 6.80 3.87 0.00 172.00 6.80 3.87 0.00
70.00 6.80 3.87 0.00 174.00 6.80 3.87 0.00
72.00 6.80 3.87 0.00 176.00 6.80 3.87 0.00
74.00 6.80 3.87 0.00 178.00 6.80 3.87 0.00
76.00 6.80 3.87 0.00 180.00 6.80 3.87 0.00
78.00 6.80 3.87 0.00 182.00 6.80 3.87 0.00
80.00 6.80 3.87 0.00 184.00 6.80 3.87 0.00
82.00 6.80 3.87 0.00 186.00 6.80 3.87 0.00
84.00 6.80 3.87 0.00 188.00 6.80 3.87 0.00
86.00 6.80 3.87 0.00 190.00 6.80 3.87 0.00
88.00 6.80 3.87 0.00 192.00 6.80 3.87 0.00
90.00 6.80 3.87 0.00 194.00 6.80 3.87 0.00
92.00 6.80 3.87 0.00 196.00 6.80 3.87 0.00
94.00 6.80 3.87 0.00 198.00 6.80 3.87 0.00
96.00 6.80 3.87 0.00 200.00 6.80 3.87 0.00
98.00 6.80 3.87 0.00
100.00 6.80 3.87 0.00
102.00 6.80 3.87 0.00

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 33
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Subcatchment 2S: (Post Developed)
Runoff = 90.33 cfs @ 11.96 hrs, Volume= 4.379 af, Depth= 5.29"
Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Type II 24-hr 50-yr Concord Rainfall=6.80"
Area (ac) CN Description
4.380 98 Paved parking & roofs
5.560 79 50-75% Grass cover, Fair, HSG C
9.940 87 Weighted Average
5.560 Pervious Area
4.380 Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 34
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Subcatchment 2S: (Post Developed)
Time Precip. Excess Runoff Time Precip. Excess Runoff
(hours) (inches) (inches) (cfs) (hours) (inches) (inches) (cfs)
0.00 0.00 0.00 0.00 104.00 6.80 5.29 0.00
2.00 0.15 0.00 0.00 106.00 6.80 5.29 0.00
4.00 0.33 0.00 0.03 108.00 6.80 5.29 0.00
6.00 0.54 0.03 0.31 110.00 6.80 5.29 0.00
8.00 0.82 0.13 0.66 112.00 6.80 5.29 0.00
10.00 1.23 0.36 1.62 114.00 6.80 5.29 0.00
12.00 4.51 3.11 75.43 116.00 6.80 5.29 0.00
14.00 5.58 4.11 2.50 118.00 6.80 5.29 0.00
16.00 5.98 4.50 1.53 120.00 6.80 5.29 0.00
18.00 6.26 4.77 1.19 122.00 6.80 5.29 0.00
20.00 6.47 4.97 0.86 124.00 6.80 5.29 0.00
22.00 6.64 5.14 0.79 126.00 6.80 5.29 0.00
24.00 6.80 5.29 0.73 128.00 6.80 5.29 0.00
26.00 6.80 5.29 0.00 130.00 6.80 5.29 0.00
28.00 6.80 5.29 0.00 132.00 6.80 5.29 0.00
30.00 6.80 5.29 0.00 134.00 6.80 5.29 0.00
32.00 6.80 5.29 0.00 136.00 6.80 5.29 0.00
34.00 6.80 5.29 0.00 138.00 6.80 5.29 0.00
36.00 6.80 5.29 0.00 140.00 6.80 5.29 0.00
38.00 6.80 5.29 0.00 142.00 6.80 5.29 0.00
40.00 6.80 5.29 0.00 144.00 6.80 5.29 0.00
42.00 6.80 5.29 0.00 146.00 6.80 5.29 0.00
44.00 6.80 5.29 0.00 148.00 6.80 5.29 0.00
46.00 6.80 5.29 0.00 150.00 6.80 5.29 0.00
48.00 6.80 5.29 0.00 152.00 6.80 5.29 0.00
50.00 6.80 5.29 0.00 154.00 6.80 5.29 0.00
52.00 6.80 5.29 0.00 156.00 6.80 5.29 0.00
54.00 6.80 5.29 0.00 158.00 6.80 5.29 0.00
56.00 6.80 5.29 0.00 160.00 6.80 5.29 0.00
58.00 6.80 5.29 0.00 162.00 6.80 5.29 0.00
60.00 6.80 5.29 0.00 164.00 6.80 5.29 0.00
62.00 6.80 5.29 0.00 166.00 6.80 5.29 0.00
64.00 6.80 5.29 0.00 168.00 6.80 5.29 0.00
66.00 6.80 5.29 0.00 170.00 6.80 5.29 0.00
68.00 6.80 5.29 0.00 172.00 6.80 5.29 0.00
70.00 6.80 5.29 0.00 174.00 6.80 5.29 0.00
72.00 6.80 5.29 0.00 176.00 6.80 5.29 0.00
74.00 6.80 5.29 0.00 178.00 6.80 5.29 0.00
76.00 6.80 5.29 0.00 180.00 6.80 5.29 0.00
78.00 6.80 5.29 0.00 182.00 6.80 5.29 0.00
80.00 6.80 5.29 0.00 184.00 6.80 5.29 0.00
82.00 6.80 5.29 0.00 186.00 6.80 5.29 0.00
84.00 6.80 5.29 0.00 188.00 6.80 5.29 0.00
86.00 6.80 5.29 0.00 190.00 6.80 5.29 0.00
88.00 6.80 5.29 0.00 192.00 6.80 5.29 0.00
90.00 6.80 5.29 0.00 194.00 6.80 5.29 0.00
92.00 6.80 5.29 0.00 196.00 6.80 5.29 0.00
94.00 6.80 5.29 0.00 198.00 6.80 5.29 0.00
96.00 6.80 5.29 0.00 200.00 6.80 5.29 0.00
98.00 6.80 5.29 0.00
100.00 6.80 5.29 0.00
102.00 6.80 5.29 0.00

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 35
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Pond 3P: (BMP6)
Inflow Area = 9.940 ac, Inflow Depth = 5.29" for 50-yr Concord event
Inflow = 90.33 cfs @ 11.96 hrs, Volume= 4.379 af
Outflow = 38.36 cfs @ 12.05 hrs, Volume= 4.378 af, Atten= 58%, Lag= 5.6 min
Primary = 34.60 cfs @ 12.05 hrs, Volume= 4.349 af
Secondary= 3.76 cfs @ 12.05 hrs, Volume= 0.029 af
Routing by Stor-Ind method, Time Span= 0.00-200.00 hrs, dt= 0.01 hrs
Peak Elev= 623.27' @ 12.05 hrs Surf.Area= 22,642 sf Storage= 91,796 cf
Plug-Flow detention time= 623.7 min calculated for 4.378 af(100% of inflow)
Center-of-Mass det. time= 623.6 min ( 1,409.8 - 786.2 )
Volume Invert Avail.Storage Storage Description _
#1 618.00' 108,921 cf Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store
(feet) (sq-ft) (cubic-feet) (cubic-feet)
618.00 12,647 0 0
620.00 16,095 28,742 28,742
622.00 19,943 36,038 64,780
624.00 24,198 44,141 108,921
Device Routing Invert Outlet Devices
#1 Primary 596.11' 18.0" x 18.0' long Culvert RCP, square edge headwall, Ke= 0.500
Outlet Invert= 596.00' S= 0.0061 '/' Cc= 0.900 n= 0.013
#2 Device 1 618.00' Exfiltration
Head (feet) 0.00 1.00 2.00 3.00 4.00 5.00 6.00
Disch. (cfs) 0.000 0.155 0.217 0.279 0.342 0.404 0.466
#3 Device 1 620.00' 6.0"Vert. Orifice/Grate C= 0.600
#4 Device 1 622.00' 2.00'x 3.00' Horiz. Top of Riser Limited to weir flow C= 0.600
#5 Secondary 623.00' 10.0' long x 16.0' breadth Spillway
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60
Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
Primary OutFlow Max=34.60 cfs @ 12.05 hrs HW=623.27' (Free Discharge)
t-1=Culvert (Passes 34.60 cfs of 43.73 cfs potential flow)
2=Exfiltration (Custom Controls 0.42 cfs)
3=Orifice/Grate (Orifice Controls 1.64 cfs @ 8.36 fps)
4=Top of Riser (Orifice Controls 32.53 cfs @ 5.42 fps)
Secondary OutFlow Max=3.73 cfs @ 12.05 hrs HW=623.27' (Free Discharge)
t-5=Spillway (Weir Controls 3.73 cfs @ 1.39 fps)

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 36
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Hydrograph for Pond 3P: (BMP6)
Time Inflow Storage Elevation Outflow Primary Secondary
(hours) (cfs) (cubic-feet) (feet) (cfs) (cfs) (cfs)
0.00 0.00 0 618.00 0.00 0.00 0.00
5.00 0.16 323 618.03 0.00 0.00 0.00
10.00 1.62 11,567 618.86 0.13 0.13 0.00
15.00 1.99 66,092 622.07 2.20 2.20 0.00
20.00 0.86 59,849 621.75 1.48 1.48 0.00
25.00 0.00 47,241 621.08 1.15 1.15 0.00
30.00 0.00 33,038 620.26 0.42 0.42 0.00
35.00 0.00 28,171 619.96 0.21 0.21 0.00
40.00 0.00 24,437 619.73 0.20 0.20 0.00
45.00 0.00 20,961 619.50 0.19 0.19 0.00
50.00 0.00 17,730 619.29 0.17 0.17 0.00
55.00 0.00 14,733 619.08 0.16 0.16 0.00
60.00 0.00 12,007 618.89 0.14 0.14 0.00
65.00 0.00 9,742 618.73 0.11 0.11 0.00
70.00 0.00 7,889 618.60 0.09 0.09 0.00
75.00 0.00 6,377 618.49 0.08 0.08 0.00
80.00 0.00 5,148 618.40 0.06 0.06 0.00
85.00 0.00 4,150 618.32 0.05 0.05 0.00
90.00 0.00 3,343 618.26 0.04 0.04 0.00
95.00 0.00 2,691 618.21 0.03 0.03 0.00
100.00 0.00 2,164 618.17 0.03 0.03 0.00
105.00 0.00 1,740 618.14 0.02 0.02 0.00
110.00 0.00 1,398 618.11 0.02 0.02 0.00
115.00 0.00 1,123 618.09 0.01 0.01 0.00
120.00 0.00 902 618.07 0.01 0.01 0.00
125.00 0.00 724 618.06 0.01 0.01 0.00
130.00 0.00 581 618.05 0.01 0.01 0.00
135.00 0.00 467 618.04 0.01 0.01 0.00
140.00 0.00 375 618.03 0.00 0.00 0.00
145.00 0.00 301 618.02 0.00 0.00 0.00
150.00 0.00 241 618.02 0.00 0.00 0.00
155.00 0.00 194 618.02 0.00 0.00 0.00
160.00 0.00 156 618.01 0.00 0.00 0.00
165.00 0.00 125 618.01 0.00 0.00 0.00
170.00 0.00 100 618.01 0.00 0.00 0.00
175.00 0.00 80 618.01 0.00 0.00 0.00
180.00 0.00 65 618.01 0.00 0.00 0.00
185.00 0.00 52 618.00 0.00 0.00 0.00
190.00 0.00 42 618.00 0.00 0.00 0.00
195.00 0.00 33 618.00 0.00 0.00 0.00
200.00 0.00 27 618.00 0.00 0.00 0.00

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 37
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Discharge for Pond 3P: (BMP6)
Elevation Discharge Primary Secondary Elevation Discharge Primary Secondary
(feet) (cfs) (cfs) (cfs) (feet) (cfs) (cfs) (cfs)
618.00 0.00 0.00 0.00 623.20 36.08 33.69 2.40
618.10 0.02 0.02 0.00 623.30 39.43 35.01 4.42
618.20 0.03 0.03 0.00 623.40 43.12 36.29 6.83
618.30 0.05 0.05 0.00 623.50 47.07 37.52 9.55
618.40 0.06 0.06 0.00 623.60 51.26 38.71 12.55
618.50 0.08 0.08 0.00 623.70 55.51 39.87 15.64
618.60 0.09 0.09 0.00 623.80 59.89 40.99 18.89
618.70 0.11 0.11 0.00 623.90 64.59 42.09 22.50
618.80 0.12 0.12 0.00 624.00 69.45 43.15 26.30
618.90 0.14 0.14 0.00
619.00 0.15 0.15 0.00
619.10 0.16 0.16 0.00
619.20 0.17 0.17 0.00
619.30 0.17 0.17 0.00
619.40 0.18 0.18 0.00
619.50 0.19 0.19 0.00
619.60 0.19 0.19 0.00
619.70 0.20 0.20 0.00
619.80 0.20 0.20 0.00
619.90 0.21 0.21 0.00
620.00 0.22 0.22 0.00
620.10 0.25 0.25 0.00
620.20 0.34 0.34 0.00
620.30 0.46 0.46 0.00
620.40 0.60 0.60 0.00
620.50 0.72 0.72 0.00
620.60 0.81 0.81 0.00
620.70 0.89 0.89 0.00
620.80 0.97 0.97 0.00
620.90 1.04 1.04 0.00
621.00 1.10 1.10 0.00
621.10 1.16 1.16 0.00
621.20 1.21 1.21 0.00
621.30 1.27 1.27 0.00
621.40 1.32 1.32 0.00
621.50 1.37 1.37 0.00
621.60 1.42 1.42 0.00
621.70 1.46 1.46 0.00
621.80 1.51 1.51 0.00
621.90 1.55 1.55 0.00
622.00 1.59 1.59 0.00
622.10 2.67 2.67 0.00
622.20 4.60 4.60 0.00
622.30 7.09 7.09 0.00
622.40 10.03 10.03 0.00
622.50 13.35 13.35 0.00
622.60 17.03 17.03 0.00
622.70 21.02 21.02 0.00
622.80 25.30 25.30 0.00
622.90 29.34 29.34 0.00
623.00 30.86 30.86 0.00
623.10 33.15 32.31 0.85

2020.17-BMP6 Type 1124-hr 50-yr Concord Rainfall=6.80"
Prepared by {enter your company name here} Page 38
HydroCAD®8.00 s/n 004317 ©2006 HydroCAD Software Solutions LLC 1/23/2023
Stage-Area-Storage for Pond 3P: (BMP6)
Elevation Surface Storage Elevation Surface Storage
(feet) (sq-ft) (cubic-feet) (feet) (sq-ft) (cubic-feet)
618.00 12,647 0 623.20 22,496 90,243
618.10 12,819 1,273 623.30 22,709 92,504
618.20 12,992 2,564 623.40 22,921 94,785
618.30 13,164 3,872 623.50 23,134 97,088
618.40 13,337 5,197 623.60 23,347 99,412
618.50 13,509 6,539 623.70 23,560 101,757
618.60 13,681 7,899 623.80 23,772 104,124
618.70 13,854 9,275 623.90 23,985 106,512
618.80 14,026 10,669 624.00 24,198 108,921
618.90 14,199 12,081
619.00 14,371 13,509
619.10 14,543 14,955
619.20 14,716 16,418
619.30 14,888 17,898
619.40 15,061 19,395
619.50 15,233 20,910
619.60 15,405 22,442
619.70 15,578 23,991
619.80 15,750 25,557
619.90 15,923 27,141
620.00 16,095 28,742
620.10 16,287 30,361
620.20 16,480 31,999
620.30 16,672 33,657
620.40 16,865 35,334
620.50 17,057 37,030
620.60 17,249 38,745
620.70 17,442 40,480
620.80 17,634 42,234
620.90 17,827 44,007
621.00 18,019 45,799
621.10 18,211 47,611
621.20 18,404 49,441
621.30 18,596 51,291
621.40 18,789 53,161
621.50 18,981 55,049
621.60 19,173 56,957
621.70 19,366 58,884
621.80 19,558 60,830
621.90 19,751 62,795
622.00 19,943 64,780
622.10 20,156 66,785
622.20 20,369 68,811
622.30 20,581 70,859
622.40 20,794 72,927
622.50 21,007 75,017
622.60 21,220 77,129
622.70 21,432 79,261
622.80 21,645 81,415
622.90 21,858 83,590
623.00 22,071 85,787
623.10 22,283 88,004