Author(s)

R. Ahmed, S. Ali

Abstract

Intensity duration frequency curves are an important tool in calculating the rainfall intensities for various return period and storm durations. Normal distribution, lognormal distribution, Gumbel extreme value type 1 distribution and log Pearson distribution were used to derive the IDF curves for the region of Lahore City. 24 hours’ data was processed using an Indian meteorological formula to obtain rainfall intensities for durations of 1, 2, 3, 6, 12 and 18 hours, due to the lack of rainfall records. These records were used further to develop IDF curves. Intensity duration frequency curves show the relationship between the rainfall intensity (y-axis) and duration of rainfall event (x-axis), with a separate curve for each return period. IDF curves were plotted for the return periods of 2, 5, 10, 25 and 50. Rainfall intensities obtained from each distribution were used to calculate the values of parameters in rainfall intensities formula.

Keywords

IDF curves, rainfall duration, rainfall intensity, return periods, Lahore City, probability distribution, goodness of fit, Indian meteorological formula