Monthly and Annual Maximum Rainfall Prediction using Best Fitted Probability Distributions in Junagadh Region (Gujarat- India)

Rainfall is a meagre and crucial hydrological parameter in arid and semi-arid region. Junagadh (Gujarat-India) reels under monsoon rainfall uncertainties and thereby the agriculture and other water resources management activities suffer. Therefore, urgent attention is needed to address water resources conservation and crop damage issues due to deficits or excess rainfall. The amount of runoff produced and rainfall received determine the development of water resources in any region. Appropriate probability distributions need to be selected and fitted to the historical rainfall time series for better frequency analysis and forecasting of the rainfall. The daily rainfall data was collected for a period of 38 years i.e., from 1984 to 2021. In this study an attempt was made to find the most appropriate probability distributions for the better prediction of maximum rainfall by fitting the eight different hypothetical probability distributions to the monthly and annual maximum rainfall for one to five consecutive days. Chi-Square and Nash-Sutcliffe Efficiency were employed to determine goodness of fit. The results indicated that the Gumbel distribution appears to be the best fit to predict monthly and annual maximum rainfall of Junagadh region.