An area consists almost entirely of sandy loam, which typically has a saturated hydraulic conductivity of 11 mm/h, average suction head of 110 mm, porosity of 0.45, field capacity of 0.190, wilting point of 0.085, and depression storage of 4 mm. The design rainfall is given as

Interval (min) Ave. rainfall (mm/h)
0-10 10
20-Oct 20
20-30 80
30-40 100
40-50 80
50-60 10

Use Green-Ampt method to determine the runoff versus time. Assume initial moisture content of 0.076. Ignore the depression storage.