Direction: A four hour unit hydrograph of a catchment is traingular in shape with base of 80 hours. The area of the catchment is 720 km². The base flow and f-index are 30 m³/s and 1 mm/h, respectively. A storm of a 4 cm occurs uniformly in 4 hours over the catchment.
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The peak discharge of four hour unit hydrograph is
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- 40 m³/s
- 50 m³/s
- 60 m³/s
- 70 m³/s
Correct Option: B
Area of UH = Area of catchment × unit depth
| = | × (80 × 60 × 60) × QP | |
| 2 |
Volume of rain fall = A × 1 cm
= 720 × 106 × 0.01 m
| ∴ | × 80 × 60 × 60 × QP | |
| 2 |
= 720 × 106 × 0.01
∴ Qp = 50 m³/s
