and an average slope of 0.5%.Calculate the time of concentration using the kinematic-wave equation. The drainage channel is to be sized for the peak runoff rate resulting from a 10-year rainfall event, and the 10-year IDF curve is given by i=150(t+8.96)0.78 cm/h where i is the average rainfall intensity in cm/h and t is the duration in minutes. The minimum time of concentration is 5 min. Determine the peak runoff rate.
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