Neco 2021 Geography Question 6

Using the data below, determine which river basin (A, B or C) is expected to incur the highest annual flood damage cost. Basin A: annual rainfall 1200 mm, average slope 5 %, catchment area 250 km², population density 150 persons/km², average household size 5 persons, average property value per household ₦2,000,000. Basin B: annual rainfall 900 mm, average slope 8 %, catchment area 180 km², population density 200 persons/km², average household size 4 persons, average property value per household ₦1,500,000. Basin C: annual rainfall 1100 mm, average slope 6 %, catchment area 300 km², population density 120 persons/km², average household size 5 persons, average property value per household ₦2,500,000. The probability of flooding for a basin is estimated by \( P = \frac{R \times S}{10{,}000 \times A} \) where \(R\) is rainfall (mm), \(S\) is slope (%), and \(A\) is catchment area (km²). Expected annual damage = \( P \times (\text{total property value}) \). Identify the basin with the greatest expected damage.