Variability of the Large Reservoir’s Water Inflow in Thailand

Abstract

The inflow of water into the reservoir is crucial for managing water during both drought and flooding. This study intends to investigate Thailand's Large reservoirs' fluctuating inflow. The reservoir’s water Inflow data recorded by the Royal Irrigation Department (RID) and the Electricity Generating Authority of Thailand (EGAT) were utilized in this research. The annual reservoir’s inflow, inflows of wet season, and inflows of dry season of each reservoir were analyzed using the general statistical method and the non-parametric Mann-Kendall test (MK), significant level p-value 0.05. The results indicated that the 5 reservoirs’ yearly inflows had a significant increase trend, but the annual inflows of 2 reservoirs showed a notable reduction trend. In the rainy season, 5 reservoirs had also a remarkable inflows trend. Moreover, 6 reservoirs’ inflows of dry season showed a significant rise trend while 4 reservoirs had had a significant drop trend of inflow. The finding of this study will be useful for the sustainable reservoir management of all 35 reservoirs and monitoring water shortage in the dry season, especially Bhumibol, Khun Dan Praharnchon, Nam Un, and Mae Ngad Reservoirs.