Time Series Models for Reservoir Inflows in Thailand

In the past decades, drought has become an escalating issue in many parts of Thailand and around the world as a result of the impact of climate change increasing the temperature. Droughts do not only affect agriculture and industry but also human health and the environment. The efficient operation and management of water resources are crucial. Reservoir is one of the key factors of water resources operation and management. Therefore, it requires the accurate forecasting of the reservoir inflows. The monthly reservoir inflow data of Bhumibol and Sirikit Dams, Thailand collected by Water Analysis and Assessment Division, the Royal Irrigation Department were analysed to obtain the best-fitting models for the reservoir inflows. The time series models employed in this paper are Winters' exponential smoothing, autoregressive integrated moving average, time series regression, and combined forecasting models. The findings indicate that the simple average-based combination and time series regression models are the most accurate models for forecasting the reservoir inflows of Bhumibol and Sirikit Dams respectively.