SW3220305_Design Calculations_20220325 (3)

SUBJECT: Swale Sizing
SYSTEM:O
CLIENT: Water and Sewer Authority of Cabarrus County
PROJECT NAME: Rocky River Regional WA/TP Expansion Phase 3
PROJECT NUMBER: 156673
Calculations to size the stormwater pipes throughout the site
C Factors
I m pervious Area 0.95
Pervious Area -Grass 0.3
Pervious Area -Soil 0.6
Basin Areas and C Factors
DISCIPLINE: Civil
CREATED BY: Daniel Wright
CHECKED BY: Kim Devendorf
DATE: 2/7/22
CURRENT
REVISION: 0
STANDARD APPLICATION SOFTWARE USED
QC Checker Section Sign -Off:
Software Name
REFERENCES
QC Checker Section Sign -Off: -
Document Name
CALCULATION BASIS AND ASSUMPTIONS
QC Checker Section Sign -Off: -
Impervious
Swale #
Area x
C Impery + Pervious area
x C' Pery
_ Total Area = Composite'C'
1
0.00
0.95 2.30
0.3
2.30 0.30
2
0.05
0.95 1.55
0.3
1.61 0.32
3
0.03
0.95 0.03
0.3
0.06 0.64
4
0.08
0.95 0.42
0.3
0.50 0.40
5
0.11
0.95 0.35
0.3
0.46 0.46
TOC (min) 5.00 Assumed
Intensity (10-yr) (in/hr) 7.32
Swale Flow (Q=CIA)
Swale # Q (cfs)
1
5.06
2
3.77
3
0.27
4
1.48
5
1.55
Swale Dimensions
Note: b = 0 for triangular channels and z = 0 for rectangular channels.
n �1
z
b
NOTE: For figure of swale locations and contributing drainage areas, see '11_RRRWVVTP-Ditch-DA.pdf'
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02/14/22 9:57 AM

Swale 1 (EQ Tanks)
Input
Flow Rate (Q) =
5.06 cfs
Manning's n (n)
0.035
Downstream Slope (S)
0.0075 ft/ft
Base Width (b)
0.0 ft
Side Slope (z)
3.50
Uniform Flow Depth
Flow Area (A) =
2.51 ftZ
Wetted Perim. (P) =
6.16 ft
Hydraulic Rad. (R) =
0.41 ft
Manning Convey. (K)'=
58.4 cfs
err1"=
0.0000 cfs
Unif. Flow Depth (y )=
0.85 ft
Critical Flow Depth
Flow Area (A) =
1.55 ftZ
Wetted Perim. (P) =
4.84 ft
Hydraulic Rad. (R) =
0.32 ft
Top Width (T) =
4.65 ft
err2"` =
0.0000 ft,
Crit. Flow Depth (y,)=
0.66 ft
Velocity
Velocity (V)
2.02 fps
Swale 2 (EQ Road North)
Input
Flow Rate (Q) =
3.77 cfs
Manning's n (n)
0.035
Downstream Slope (S)
0.0150 ft/ft
Base Width (b)
0.5 ft
Side Slope (z)
3.00
Uniform Flow Depth
Flow Area (A) =
1.50 ftZ
Wetted Perim. (P) =
4.48 ft
Hydraulic Rad. (R) =
0.34 ft
Manning Convey. (K)'=
30.8 cfs
err1"=
0.0000 cfs
Unif. Flow Depth (y )=
0.63 ft
Critical Flow Depth
Flow Area (A) =
1.19 ftZ
Wetted Perim. (P) =
3.99 ft
Hydraulic Rad. (R) =
0.30 ft
Top Width (T) =
3.81 ft
err2"` =
0.0000 ft,
Crit. Flow Depth (yc)=
0.55 ft
Velocity
Velocity (V)
2.51 fps
Swale 3 (Maintenance CanoDV Ditch West) Swale 4 (Maintenance Canonv East)
Input
Flow Rate (Q) =
0.27 cfs
Manning's n (n)
0.035
Downstream Slope (S)
0.0700 ft/ft
Base Width (b)
0.0 ft
Side Slope (z)
3.00
Uniform Flow Depth
Flow Area (A) =
0.12 ftZ
Wetted Perim. (P) =
1.24 ft
Hydraulic Rad. (R) =
0.09 ft
Manning Convey. (K)'=
1.0 cfs
err1"=
0.0000 cfs
Unif. Flow Depth (y )=
0.20 ft
Critical Flow Depth
Flow Area (A) =
0.14 ftZ
Wetted Perim. (P) =
1.38 ft
Hydraulic Rad. (R) =
0.10 ft
Top Width (T) =
1.30 ft
err2"` =
0.0000 ft,
Crit. Flow Depth (yc)=
0.22 ft
Velocity
Velocity (V)
0.30 fps
Swale 5 (Thickenina Sludae PUmD Station No. 2)
Input
Flow Rate (Q) =
1.55 cfs
Manning's n (n)
0.035
Downstream Slope (S)
0.0200 ft/ft
Base Width (b)
0.0 ft
Side Slope (z)
3.00
Uniform Flow Depth
Flow Area (A) =
0.69 ftZ
Wetted Perim. (P) =
3.03 ft
Hydraulic Rad. (R) =
0.23 ft
Manning Convey. (K)'=
10.9 cfs
err1"=
0.0000 cfs
Unif. Flow Depth (y )=
0.48 ft
Critical Flow Depth
Flow Area (A) =
0.58 ftZ
Wetted Perim. (P) =
2.78 ft
Hydraulic Rad. (R) =
0.21 ft
Top Width (T) =
2.64 ft
err2"` =
0.0000 ft,
Crit. Flow Depth (yJ=
0.44 ft
Velocity
Input
Flow Rate (Q) =
1.48 cfs
Manning's n (n)
0.035
Downstream Slope (S)
0.0850 ft/ft
Base Width (b)
0.0 ft
Side Slope (z)
3.00
Uniform Flow Depth
Flow Area (A) =
0.39 ftZ
Wetted Perim. (P) =
2.28 ft
Hydraulic Rad. (R) =
0.17 ft
Manning Convey. (K)'=
5.1cfs
err1"=
0.0000 cfs
Unif. Flow Depth (y )=
0.36 ft
Critical Flow Depth
Flow Area (A) =
0.56 ftZ
Wetted Perim. (P) =
2.74 ft
Hydraulic Rad. (R) =
0.21 ft
Top Width (T) =
2.60 ft
err2"` =
0.0000 ft,
Crit. Flow Depth (yc)=
0.43 ft
Velocity
Velocity (V)
0.09 fps
*Manning's conveyance equals (1.486/n)AR2/3
-Manning's Q - Given Q
"`Q2/g - A3/T