A study of maximum point and areal rainfall in the Bhima basin up to Ujjani dam site

Abstract

 In this study both point and areal rainfall analyses have been attempted for the Bhima basin upto Ujjani dam site. Point rainfall magnitudes for the stations within the basin have been worked out for 2 and 100-year return periods and a nomogram has been prepared by which rainfall magnitudes for the Intermediate return periods of 5, 10, 25 and 50 years can be determined. Design rainfall for the basin has been calculated for 100, 500 and 1000-yoor return periods on the basis of 7.5 years' rainstorm analyses of the basin. Maximum rainfall experienced over this basin during the last 75-year period has also been compared with the maximum rainfall experienced in the neighboring basins of Godavari and Krishna for different durations. Mean annual rainfall of the basin was found to be of the order of 37 inches of which 92 per cent is contributed during the monsoon months of June to October. It was also observed that in this region maximum 1,2 and 3-day basin rainfall are about 12, 18 and 23 per cent respectively of the mean annual basin rainfall.