Changes in Rainfall in Sri Lanka During 1966 - 2015

Water plays a major role in agriculture and rainfall has been the primary source of water for agriculture all over the world. Rainfall has also been the primary source for hydropower generation, drinking water supply as well as many industries. In contrast, rainfall also causes disasters such as floods and landslides. Thus, rainfall affects our lives in many ways. This study was to analyse the annual and seasonal rainfall trends in Sri Lanka during the 50 year period from 1966 to 2015 using rainfall data collected at 32 rain gauging stations. The seasons considered were the two principal monsoon seasons and the two inter-monsoon seasons. Non-parametric Mann-Kendall trend test and Sen¿s Slope estimator method were used to examine the rainfall trends and determine their magnitudes.