Analysis of monsoon rainfall variability over Narmada basin in central India: Implication of climate change

Daily rainfall of 23 high resolution (1° × 1°) grid cells covering the Narmada basin has been analyzed to investigate the trend in extreme rainfall events. The trend analysis of the 1-day maximum rainfall series showed a significant positive trend at 95% significance level with the Mann–Kendall test statistic value of z = 3.66 over the entire basin. The analysis further suggested that there has been an increasing trend in the magnitude of 1-day maximum rainfall over the basin with more areas in the basin experiencing high intensity storms, which was more prominent in the most recent 20 years. Drought duration estimated by the standardized precipitation index for the periods 1951–1970 and 1989–2008 indicated that the entire basin has experienced frequent droughts during the recent two decades, with the middle zone of the basin being more prone to droughts. The analysis also suggested that appropriate measures may be proposed for better management of the water resources in the basin, and also for mitigation of floods and droughts, considering the increased risk of the high intensity storms as well as the increased frequency of drought occurrence during the recent two decades.