Investigating Rainfall Trend and Monitoring Meteorological Drought in a Himalayan Watershed of India

Assessment of rainfall trend and monitoring meteorological drought and wet conditions are very important in dealing with agricultural planning and water resources management under the influence of changing climate in the Himalayan region. This study was conducted to assess rainfall trend and monitor the drought and wet pattern at four stations, namely Naula, Kedar, Chaukhutia and Mehalchauri, located in the upper Ramganga River catchment in Uttarakhand state of India in the central Himalayan region. Rainfall trend analysis at these stations was carried out using MannKendall test and Sen’s slope estimator. Standardized Precipitation Index (SPI) at multiple time scales of 1-, 3-, 6-, 9-, 12and 24-months was used to assess meteorological drought and wet pattern at Naula station. Results have indicated a significantly downward trend in December and postmonsoon season and an upward trend in September at Naula station. Significantly downward trend was also observed in July, December and monsoon season at Kedar station, and in June, July, August, monsoon and annual data series at Chaukhutia station. No significant trend was observed at Mehalchauri station. Study also revealed that there are more chances of occurrences of mild drought and wet conditions and only meager chances of moderate drought and wet conditions during monsoon season. However, the chances of severe and extreme drought and wet conditions are almost negligible. Therefore, efforts must be made to harvest the excess water during the wet periods and utilize the same during the periods of mild and moderate drought for drinking, household activities and irrigation purposes.