Waec Model Questions Vol1 2020 Geography Question 26
Practice objective / multiple choice question 26 from the 2020 Waec Model Questions Vol1 Geography examination.
A catchment area of 250 km² receives an annual rainfall of 1200 mm. The land use is 40% forest (runoff coefficient 0.15), 35% agricultural land (coefficient 0.30) and 25% urban (coefficient 0.70). For a design storm of 2‑hour duration the rainfall intensity is 30 mm/h. A rectangular river channel 12 m wide and 3 m deep conveys the runoff, but to avoid bank erosion the water velocity must not exceed 2 m/s. Using the rational method Q = C i A, determine the minimum channel width (in metres, rounded up to the nearest whole metre) required to convey the peak discharge safely, keeping the depth at 3 m and the velocity limit at 2 m/s.
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About This Question
This is Waec Model Questions Vol1 2020 Geography Question 26. It is one of the objective questions from the 2020 Waec Model Questions Vol1 Geography examination.
Difficulty level: Hard .
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