Author(s): Ruetaitip Mama, Butsawan Biborn, Kwan Sue Jung, Matharit Namsai, Methat Yuenpraphan
Linked Author(s): Ruetaitip Mama
Keywords: Long-term rainfall trend, rainfall indices, Mann-Kendall test, extreme rainfall events, climate change.
Abstract: Climate change is a global issue and is one of the major concerns in water resources planning and management during the past decades. Changing rainfall pattern can directly affect an occurrence of an extreme event on floods and droughts, which will cause future conflicts especially on water supply and flood management. The purpose of this study is to examine the variability of rainfall in the Yom River basin, Thailand, over the past 90 years (1921�2015). This study evaluates long-term trends in rainfall and various rainfall-related extreme events, which consist of the annual precipitation (PRCTPOP), consecutive dry days (CDD), consecutive wet days (CWD), number of heavy rainfall days (R10), number of very heavy rainfall days (R20), daily maximum rainfall (Rmax1), five-day maximum rainfall (Rmax5), and annual total rainy day (Rday) in the Yom River basin, Thailand. Rainfall dataset from 13 hydrological stations across the basin are analyzed using the Mann-Kendall method at 95 percent confident level. Analyses of these data showed that the average annual rainfall of the whole basin varies between 1, 018 and 1, 179 mm with the minimum and maximum annual rainfall of 480 and 4, 047 mm/y, respectively. The results from this study reveals that an increasing trend are dominating in 3 indices as Rmax1, CWD and Rday, while the decreasing trend are dominating in the remaining in 5 indices as PRCPTOT, Rmax5, CDD, R10, and R20 during the past century. Results of this study indicate that the Yom River basin is highly vulnerable to droughts and floods driven by the variability in rainfall. The impacts of changes in rainfall pattern in the Yom River basin should be considered in the future water resources planning and management of the country
Year: 2017