QUESTION TWO (Total of 25 marks) (a) Discuss how to determine the critical duration of the storm and the corresponding a

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Question Two Total Of 25 Marks A Discuss How To Determine The Critical Duration Of The Storm And The Corresponding A 1 (40.97 KiB) Viewed 44 times

QUESTION TWO (Total of 25 marks) (a) Discuss how to determine the critical duration of the storm and the corresponding average storm intensity when estimating the peak discharge for an outlet for a given recurrence interval using rational method and Time-Area method. (3 marks) (b) Discuss the effects of storm and basin characteristics on hydrograph shape by using the following graph. (4 marks) we L (iv) (c) A 35ha catchment has the following time-area relation. Time (min) Total contributing area (ha) (i) Time (min) Distribution (%) (ii) Time Area Equation 0 0 k=1 0-10 20% Q₁ = Σ₁-4₂ 10 5 Estimate the runoff hydrograph produced from the catchment using the time- area model for a 40 min duration storm with average intensity 75mm/hr. The rainfall temporal pattern for the storm is given below. (14 marks) 20 15 30 23 10-20 30% 40 30 20-30 30% 50 35 30-40 20% Plot the rainfall hydrograph on graph paper and estimate the total rainfall for the 40min duration storm. (4 marks)