Neco Model Questions Vol1 2017 Geography Question 28

For a catchment area of 120 km² the total length of streams measured is 180 km. The highest point in the basin is at 800 m elevation and the lowest point (river outlet) is at 200 m elevation, with a horizontal distance of 10 km between them.\n\n(a) Calculate the drainage density of the basin and state whether it is low, moderate or high, using the criterion that a drainage density greater than 1.5 km km⁻¹ is considered high.\n(b) Determine the average slope gradient (as a percentage) between the highest and lowest points and classify the slope as gentle (<5 %), moderate (5-15 %) or steep (>15 %).\n(c) Based on your results, which factor—drainage density or slope—suggests a more intense erosional environment? Provide a brief justification.