Article

Pranav B. Mistry, The Maharaja Sayajirao University of Baroda; T. M. V. Suryanarayana ,The Maharaja Sayajirao University of Baroda

Rainfall is an infrequent and an important hydrological parameter on the earth. In the design of irrigation and other hydraulic structures, evaluating the magnitude of extreme rainfall for a specific probability of occurrence is of much importance. For the present study daily rainfall data from 1968-2010 for Waghodia Taluka is collected and analysed for Annual One Day Maximum Rainfall (AODMR) using various five commonly used probability distribution viz., Gumbel’s distributions, Normal distributions, Lognormal, Log Pearson type III and Generalized Extreme distribution to determine the best fit probability distribution. The expected values were compared with the observed values using goodness of fit were determined by chi square (γ2) test. The chi-square values for Normal, Log-Normal, Log- Pearson type-III, Generalized Extreme distributions and Gumbel’s distributions and were 29.98, 29.68, 48.58, 8.40 and 4.06 respectively which shows that the Gumbel’s distribution was the best fit probability distribution to forecast annual one day maximum rainfall for different return periods. Also, expected Annual One Day Maximum Rainfall using Gumbel’s distribution for return period of 2, 5, 10, 25, 50 and 100 were 122.65mm, 177.75mm, 214.24mm, 260.34mm, 294.54mm and 328.49mm respectively. The comparisons between the observed and predicted maximum value of rainfall clearly shows that the developed model can be efficiently used for the prediction of rainfall. The results of this study would be useful for agricultural scientists, decision makers, policy planners and researchers for agricultural development and constructions of small soil and water conservation structures, irrigation and drainage systems in Gujarat, India.