Direction: The ordinates of a 2-h unit hydrograph at 1 hour intervals starting from time t = 0, are 0, 3, 8, 6, 3, 2 and 0 m³/s. Use trapezoidal rule for numerical integration, if required.
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What is the catchment area represented by the unit hydrograph?
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- 1.00 km²
- 2.00 km²
- 7.92 km²
- 8.64 km²
Correct Option: C
Volume of water = area under graph
| = |  | × 1 × 3 |  | + (3 × 1) + | | × 5 × 1 | | + | | × 2 × 1 | | + (6 × 1) + | | × 3 × 1 | | + (3 × 1) + | | × 2 × 1 | | + (2 × 1) + | | × 2 × 1 | | ||||||
| 2 | 2 | 2 | 2 | 2 | 2 |
= 22 m³ × 3600
(3600 is multiplied to convert hour to seconds)
= 79200 m³
Depth = 1 cm (UH)
| = depth | ||
| area |
| Area = | = 7.92 km² | |
| 1 |
