Question 1 Given: Vaal catchment (A = 60 km) shown in Fig. 1. Elevation vs distance 600 A - 20% Forest Silylam A = 55% Farmland Clay 520 Elevation (m) 390 400 A = 25% Pasture Sandy loan 200 0 1000 2000 3000 2000 5000 6000 Distance 1.1.Calculate the slope of the longest watercourse using (a) 1085 method (b) Equal Area method 1.2.Calculate the intensity and flood peaks corresponding to a return periods of 10, 30 and 70 years using the following methods: (a) Rational Formula (6) (b) Standard Design Flood (c) Francou Rodier Method (6) (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] Question 1 Given: Vaal catchment (A = 60 km) shown in Fig. 1. Elevation vs distance 600 A - 20% Forest Silylam A = 55% Farmland Clay 520 Elevation (m) 390 400 A = 25% Pasture Sandy loan 200 0 1000 2000 3000 2000 5000 6000 Distance 1.1.Calculate the slope of the longest watercourse using (a) 1085 method (b) Equal Area method 1.2.Calculate the intensity and flood peaks corresponding to a return periods of 10, 30 and 70 years using the following methods: (a) Rational Formula (6) (b) Standard Design Flood (c) Francou Rodier Method (6) (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]