MatLab

Sheet1

		Return Period (years)
	duration (min)	10	70	100	1000
	5	8.17		10.86	13.51
	10	6.54		8.63	10.64		x	y		Linear interpolation equation:
	15	5.52		7.27	8.9		15	5.52
	20	5.013	6.140	6.703			20	5.013		ym = y1 + (y2-y1)/(x2-x1) * (xm-x1)
	30	4		5.57	7.21		30	4
	60	2.6		3.83	5.26
	90	1.54		2.37	3.43
	120	1.1		1.75	2.63

y 15 20 30 5.52 5.0133333333333328 4

x

y

Showing in red value interpolated between two points

10-yr return period 5 10 15 20 30 60 90 120 8.17 6.54 5.52 5.0133333333333328 4 2.6 1.54 1.1000000000000001

duration (min)

Rainfal Intensity (in/hr)