5feaf3 storm water inlet design gutter inlets si units

Storm Water Inlet Design - Gutter Inlet - S.S. units

1. Orifice Equation (submerged inlet)

Inputs Calculations

Design Storm Water 0.15 m

0.16

0.30 m

300 mm

Width of Curb

150 mm 0.46 m

0.67

2. Weir Equation (unsubmerged inlet)

Inputs Calculations

Design Storm Water 0.075 m

0.034

0.23 m

75 mm

Width of Curb

230 mm 0.8 m

1.27

Depth of Storm Water, d =

Flow Rate, Q = m3/s

Width of opening, W =

Width of opening, W =

Depth of Storm Water, d = Opening, L =

Orifice Coeff., Co =

Depth of Storm Water, d =

Flow Rate, Q = m3/s

Width of opening, W =

Depth of Storm Water, d =

Width of opening, W = Opening, L =

Orifice Coeff., Cw =

Equation for Gutter Inlet Design using the Orifice Equation

Where: Q = design storm water flow rate through inlet, cfs

W = width of the gutter opening, ft

d = depth of storm water over the gutter opening, ft

L = length of the gutter opening, ft

Equation for Curb Inlet Design using the Weir Equation

Where: Q, L, W and d are as defined above

Q = Co (W L) ( 2g d )1/2 { L = Q/[CoW(2gd)1/2] }

g = 32.2 ft/sec2

Co = orifice coefficient, dimensionless ( typically Co = 0.67 )

Q = Cw (L + 2W) d1.5 [ L = Q/(Cwd1.5) - 2W ]

Cw = wier coefficient, dimensionless ( typically Cw = 1.27 )