African Journal of Soil Science ISSN 2375-088X Vol. 9 (2), pp. 001-006, February, 2021. © International Scholars Journals

Full Length Research Paper

Characterization and frequency analysis of consecutive days maximum rainfall at Boalia, Rajshahi and Bangladesh

M. A. B. Barkotulla1*, M. S. Rahman2 and M. M. Rahman3

1Department of Crop Science and Technology, University of Rajshahi, India.

2Department of Statistics, University of Rajshahi, India.

3Department of Civil Engineering, Rajshahi University of Engineering and Technology, India.

Accepted 21 July, 2020

Abstract

Probability distributions were to predict rainfall status of various return period estimating one day and two to seven consecutive days annual maximum rainfall of Boalia, Rajshahi, Bangladesh. Three commonly used probability distributions (viz: Normal, Log Normal and Gamma distribution) were tested to determine the best fit probability distribution using the comparison of chi- square values. Results showed that the log-normal distribution was the best fit probability distribution for one day and two to seven consecutive days annual maximum rainfall for the region. Based on the best fit probability distribution the maximum rainfall of 116.15, 161.09, 190.14, 205.96, 220.37, 234.66 and 245.21 mm was expected to occur 1, 2, 3, 4, 5, 6 and 7 days respectively at Boalia (Rajshahi City Corporation and surrounding areas) every two years. For a recurrence interval of 100 years, the maximum rainfall expected in 1, 2, 3, 4, 5, 6 and 7 days were 290.24, 406.49, 544.08, 558.56, 600.33, 631.28 and 633.89 mm respectively. The results of this study would be useful for agricultural scientists, decision makers, policy planners and researchers in order to identify the areas where agricultural development and construction of drainage systems in Boalia as one of the major factors causing flooding should be focused as a long-term environmental strategy for Bangladesh.

Key words: Return period, frequency, probability distribution, consecutive days’ maximum rainfall.