Analysis of current trends in climatic parameters and its effect on discharge of Satluj River basin, western Himalaya

Climate variability and change play a vital role in the susceptible system of the Satluj River basin located in western Himalaya. The Satluj River is providing precious water resources for the hydropower generation and intense agriculture in the basin. The present study provides insight into the trends in snowfall, snow cover area, rainfall and temperature (T min and T max ) with subsequent effect on river discharge. Mann–Kendall test and Sen’s slope estimator were used to evaluate annual, seasonal and monthly trends. The snowfall has decreased over the studied period of 33 years with the mean snowfall exhibiting decreasing trends annually, seasonally as well as monthly. Out of the total data, 14 stations revealed negative trends with significant trends at 8 stations. Highest number of stations with negative trends occurred during post-monsoon season. The decreasing snowfall has resulted in decrease in snow cover area in the basin. On the other hand, the annual and seasonal rainfall has increased significantly except for winter season. Station-wise, rainfall revealed mixed nature of trends with feeble increasing trends >1600 m asl elevation. Consequently, the temperature has increased with dominantly significant trends in T min . The T min showed significant rising trends at most of the stations located >1000 m asl elevation and winter season. The temperature particularly T min may be a dominant factor in controlling the trends in snowfall, snow cover area and rainfall trends. Subsequently, the annual discharge has decreased with significant decreasing trends during monsoon and post-monsoon seasons. Moreover, during regression analysis, it was observed that with increase in temperature, snowfall has decreased and rainfall increased. The negative correlation between snowfall and rainfall also substantiated the fact that the snowfall has decreased with increase in rainfall. In addition, the trend analysis also suggested the coincidence of decline in snowfall and increase in rainfall, reflecting the shifting of precipitation from solid to liquid in the basin. Thus, a decrement in snowfall along with moderate increment in rainfall and significant rise in temperature particularly T min was observed in the basin. Nevertheless, a clear link exists between the trends in climatic parameters and river discharge in the basin. Copyright Springer Science+Business Media Dordrecht 2015