(a) The Horton's initial infiltration capacity for a catchment is 204 mm/h and the constant infiltration value at saturation is 60 mm/h. For a rainfall in excess of 204 mm/h maintained at this rate for 50 minutes, the infiltrated volume was observed to be 50.6 mm. Determine the value of k in Horton's equation.

 (b) Soil infiltration characteristics (based on Horton's equation) and an observed 4-hr duration rainfall values for a 100 ha parkland catchment are given below:

f_o = 15 mm/hr, f_c = 5.0 mm/hr, k=0.6 hr^-1

     i.  Calculate the total depth of  infiltration

    ii.  What is the total volume of runoff in m³ for the observed rainfall

   iii.  Estimate f index of the catchment