2- for the following rainfall-runoff data, determine the -index and the cumulative infiltration curve based on the o-index method. Also determine the cumulative excess rainfall as a function of time. Plot these curves. The watershed areas is 0.2 square miles (20/100). Time (hr) Rainfall rate (in/hr) 1 23 4 567 1.05 1.28 0.80 0.75 0.70 0.60 0 Direct runoff (cfs) 0 30 60 45 30 15 0