Scenario 2 (30 marks) The Scenario 2 Topographical Map shows a portion of the proposed road alignment between A and B. The arrow points out where the road alignment crosses a natural drainage channel at CH 7+200, shown as "D". The catchment areahas the following characteristics: Part Area (km) Vegetation Soil Type Slope 1 2.7 Bush and shrub Gravel 21% 2 1.8 Pasture Clay 11% 3 3.2 Cultivated Silt 17% a. On Scenario 2 Topographical Map, draw the catchment boundary for D. 10 marks) b. Determine the composite runoff coefficient for the catchment area. [10 marks] C. Using the Rational Formula, determine the peak flow at "D" for a rainfall event with a return period of 20 years and duration of 25 minutes (mention the reference clearly). Scenario 2a: Topographical Map haus 280,00 A 530.0 150,00 a. gryka e Dardhes stan m. Eremecit 469.4 m. Nakos Point D. lon B Scenario 2 (30 marks) The Scenario 2 Topographical Map shows a portion of the proposed road alignment between A and B. The arrow points out where the road alignment crosses a natural drainage channel at CH 7+200, shown as "D". The catchment areahas the following characteristics: Part Area (km) Vegetation Soil Type Slope 1 2.7 Bush and shrub Gravel 21% 2 1.8 Pasture Clay 11% 3 3.2 Cultivated Silt 17% a. On Scenario 2 Topographical Map, draw the catchment boundary for D. 10 marks) b. Determine the composite runoff coefficient for the catchment area. [10 marks] C. Using the Rational Formula, determine the peak flow at "D" for a rainfall event with a return period of 20 years and duration of 25 minutes (mention the reference clearly). Scenario 2a: Topographical Map haus 280,00 A 530.0 150,00 a. gryka e Dardhes stan m. Eremecit 469.4 m. Nakos Point D. lon B