Analysis of rainfall and temperature trends in northeast India (original) (raw)

Analysis of trends in hydro-climatic variables such as rainfall, temperature and stream flow provide useful information for planning of water resources, control of flood, management of drought and agricultural production. Trends in rainfall (1982-2011) and temperature (1972-2007) in districts of Gomti River basin were assessed using the Mann-Kendall and Sen's slope estimator. Streamflow (1982-2012) at the downstream end of the basin, Maighat was also assessed and relationships between trends in streamflow and rainfall were evaluated. All the districts in the upstream area showed significant increasing trend in annual rainfall (p < 0.05) while downstream areas showed decreasing trend. A similar drift was observed in the monsoon rain. Pre-monsoon rains had increasing trend, particularly in the month of May. In contrast, post-monsoon and winter rainfall were significantly decreasing especially towards the downstream areas. Streamflow was also reducing irrespective of the scale of assessment and this could be attributed partly to the decreasing rainfall. Decrease in rainfall and consequent decline in streamflow of the basin along with increasing temperature indicate possibility of dryness in the lower basin over the years. The results of this study could be helpful in implementing adaptation and mitigation strategies for alleviating the environmental and livelihood threats in Gomti River basin.