Trend Analyses in Gridded Rainfall Data over the Sabarmati Basin

Abstract

Sabarmati basin in India has been experiencing decreased rainfall since 1960s. In the monsoon season, maximum reduction in number of rainy days was observed in the Sabarmati basin. Thus, study of rainfall in the Sabarmati basin is necessary. Therefore, gridded rainfall data of the Sabarmati basin corresponding to annual, seasonal and monthly temporal scales is used for trend analyses for the period of 54 years’ (1951 to 2004) through application of Mann-Kendall (MK) test, MK test with block-boot strapping, Sen’s slope test, innovative trend analysis plot and smoothing curve. Results showed that, statistically significant trends are present at very few grid points of annual, winter, pre-monsoon and monsoon rainfall data and almost are decreasing. Thus, if the same trend continues in future, then there will be scarcity of water and more strain on the management of water resources at the given grids in corresponding temporal scales.