Given: Vaal catchment (A = 60 km-) shown in Fig. 1. Elevation vs distance 600 560 A = 20% Forest A = 55% Farmland Clay 520 Silty loam Elevation (m) 180 440 A -25% Pasture 400 Sandy loam 0 1000 2000 3000 4000 5000 6000 Distance (mi 1.2.Calculate the intensity and flood peaks corresponding to a retum periods of 10,30 and 70 years using the following methods: (a) Rational Formula (6) Standard Design Flood ) Francou Rodier Method (d) Briefly explain the difference between the three methods. Comment the applicability of Rational formula for the catchment. (3) [Hint: use the slope obtained using the 1085 method] Given: Vaal catchment (A = 60 km-) shown in Fig. 1. Elevation vs distance 600 560 A = 20% Forest A = 55% Farmland Clay 520 Silty loam Elevation (m) 180 440 A -25% Pasture 400 Sandy loam 0 1000 2000 3000 4000 5000 6000 Distance (mi 1.2.Calculate the intensity and flood peaks corresponding to a retum periods of 10,30 and 70 years using the following methods: (a) Rational Formula (6) Standard Design Flood ) Francou Rodier Method (d) Briefly explain the difference between the three methods. Comment the applicability of Rational formula for the catchment. (3) [Hint: use the slope obtained using the 1085 method]