Direction: For a catchment, the S-curve (or S-hydrograph) due to a rainfall of intensity 1 cm/hr is given by Q = 1 – (1 + t) exp (–1) (t in hr and Q in m³/s).
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What will be the ordinate of a 2-hour unit hydrograph for this catchment at t = 3 hours ?
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- 0.13 m³/s
- 0.20 m³/s
- 0.27 m³/s
- 0.54 m³/s
Correct Option: C
S1 at 1 hour duration
= 1 – (1 + t)e–t
= 1 – (1 + 1)e–1 = 0.264 m³/s
S2 at 3 hour duration
= 1 – (1 + 3)e–3
= 0.80 m³/s
| μ³ = | = | = 0.27 m³/s. | ||
| 2 | 2 |
