Due to urban development, the storm water discharge in urban catchment increases because of
- AIncrease in air quality index
- BIncrease in population
- CIncrease in parks and gardens
- DIncrease in paved and constructed areaCorrect
Solution
Concept
Effect of urbanisation on runoff
Formula
Q = C i A (rational method)
Step-by-step solution
1. Urban development replaces open ground with roofs, roads and pavements. 2. These impervious surfaces reduce infiltration and increase the runoff coefficient C. 3. Storm water discharge and peak flow increase.
Explanation
Paved and constructed area increases the runoff coefficient and reduces the time of concentration, so the peak discharge from the same rainfall is larger.
Shortcut
Urbanisation → more impervious area → higher runoff and peak flow.
Common mistake
Choosing "increase in population".
Correct answer: D) Increase in paved and constructed area