SW3210702_Design Calculations_20240103

STORMWATER
CALCULATIONS
FOR
PROVISION CHURCH
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UNION COUNTY, NORTH CAROLINA ,�o.�t RO��''
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19311
07-27-20
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SW3210702—MAJOR MODIFICATION %,qC`E.`SO,
JULY 24, 2023 Digitally signedby Neal
Di stall signed Neal Smith,PE
Date:2023.07.24 12:59:46-04'00'
NEAL SMITH ENGINEERING,INC. Project No. 2200682
Pm4 Neat Stnit6i.. vi9ivieerivi.9, Inc. i ,A,,,
139 Pinehurst Ave.—Suite C �t
CID SouthernPines,NC 28387 ��\ `
Phone: [phone] / \\
Fax: [phone] ���
www.nsengineering.com
License No.C-1425

STORM WATER CONVEYANCE CALCULATIONS
CHANNEL #1
STORM WATER FLOW
Q=CiA
C= 0.79
i= 7.66 (10 YR)
A= 0.7998 ACRES
Q= 4.84 CFS
Q Pond= 0 cfs
Q Total= 4.84 CFS
Bottom Width "b" = 3.00 feet
Depth of Water "y" = 0.75 feet
Left Side Slope "z" = 3 to 1
Right Side Slope "z" = 3 to 1
Diameter "d" = feet
Slope "s" = 0.0500 feet per foot
Manning's "n" = 0.030 earth channel/grand
Wetted Hydraulic Channel
Section Area Perimeter Radius Conveyance Velocity
(sq. ft.) (feet) (feet) (cfs) (ft/sec)
Trapezoid 3.94 7.7434 0.5085 27.79 5.00 Allowable
4.78 10 Yr.Actual

STORM WATER CONVEYANCE CALCULATIONS
CHANNEL #2
STORM WATER FLOW
Q=CiA
C= 0.71
i= 7.66 (10 YR)
A= 0.69 ACRES
Q= 3.75 CFS
Q Pond= 0 cfs
Q Total= 3.75 CFS
Bottom Width "b" = 2.00 feet
Depth of Water "y" = 0.75 feet
Left Side Slope "z" = 3 to 1
Right Side Slope "z" = 3 to 1
Diameter "d" = feet
Slope "s" = 0.0200 feet per foot
Manning's "n" = 0.030 earth channel/grand
Wetted Hydraulic Channel
Section Area Perimeter Radius Conveyance Velocity
(sq. ft.) (feet) (feet) (cfs) (ft/sec)
Trapezoid 3.19 6.7434 0.4727 13.55 5.00 Allowable
3.48 10 Yr.Actual

STORM WATER CONVEYANCE CALCULATIONS
CHANNEL #3
STORM WATER FLOW
Q=CiA
C= 0.98
i= 7.66 (10 YR)
A= 0.065 ACRES
Q= 0.49 CFS
Q Pond= 0 cfs
Q Total= 0.49 CFS
Bottom Width "b" = 3.00 feet
Depth of Water "y" = 0.50 feet
Left Side Slope "z" = 3 to 1
Right Side Slope "z" = 3 to 1
Diameter "d" = feet
Slope "s" = 0.0450 feet per foot
Manning's "n" = 0.030 earth channel/grand
Wetted Hydraulic Channel
Section Area Perimeter Radius Conveyance Velocity
(sq. ft.) (feet) (feet) (cfs) (ft/sec)
Trapezoid 2.25 6.1623 0.3651 12.08 5.00 Allowable
2.17 10 Yr.Actual

STORM WATER CONVEYANCE CALCULATIONS
CHANNEL #4
STORM WATER FLOW
Q=CiA
C= 0.71
i= 7.66 (10 YR)
A= 0.69 ACRES
Q= 3.75 CFS
Q Pond= 0 cfs
Q Total= 3.75 CFS
Bottom Width "b" = 2.00 feet
Depth of Water "y" = 0.75 feet
Left Side Slope "z" = 3 to 1
Right Side Slope "z" = 3 to 1
Diameter "d" = feet
Slope "s" = 0.0450 feet per foot
Manning's "n" = 0.030 earth channel/grand
Wetted Hydraulic Channel
Section Area Perimeter Radius Conveyance Velocity
(sq. ft.) (feet) (feet) (cfs) (ft/sec)
Trapezoid 3.19 6.7434 0.4727 20.32 5.00 Allowable
4.61 10 Yr.Actual

Riprap Velocity Dissipator Pad for Curb Cuts
PROVISION CHURCH
UNION COUNTY,NC
NSE Job#2101403
10-Year Design Storm
New York DOT Method
BACKGROUND: Use the E&S Control Planning&Design Manual,Section 8.06.
Velocity
EQUIVALENT TO 18"RCP
V=2.57 feet per second
ZONE 1
Size Length
4 x Dia. =6.0'Long
Width @ Outlet
3 x Dia. =4.5'Wide
Width downstream
3 x Dia.x 1.25 =5.625'Wide
Solution Use 4.5'Wd X 6.0'Lg X 6'Wd X 18"Dp
Class "B"Riprap pad