The rainfall during three successive 2 hour periods are

The rainfall during three successive 2 hour periods are 0.5, 2.8 and 1.6 cm. The surface runoff resulting from this storm in 3.2 cm. The f index value of the storm is

R = P – I
I = R if R < I

φ =	P - R	=	(0.5 + 2.8 + 16) - 3.2
	t		2 + 2 + 2

= 0.2833 cm/h = 0.566 cm/2h > 0.5 cm
∴ There is no run off for first 2 hours.

Infiltration =	0.5	= 0.25 cm/h
	2

φ_index =	P - R	=	(2.8 + 1.6) - 3.2	= 0.3 cm/h
	t		4