Bangkok: Water levels in Thailand's reservoirs are expected to be lower than last year by the end of the rainy season, attributed to El Ni±o causing 10% less rainfall than normal. As a result, the Royal Irrigation Department anticipates that reservoirs nationwide will hold about 80% of their capacity, which is less than the same period last year. This forecast is prompting accelerated water management efforts to mitigate potential flooding while conserving water for the upcoming dry season.
According to Thai News Agency, Mr. Witthaya Kaewmee, Director-General of the Royal Irrigation Department, disclosed that the total water volume in reservoirs across the country is projected to be approximately 61,064 million cubic meters by November 1, 2026, equivalent to 80% of their total capacity. The reduction in water levels is primarily due to the El Ni±o phenomenon, which has caused a 10% decrease in accumulated rainfall, particularly affecting the eastern and eastern southern regions of Thailand.
Despite the overall decrease in rainfall, there remains a concern for heavy to very heavy rainfall in some areas towards the end of the rainy season. The Royal Irrigation Department is actively managing water retention areas while storing incoming water in reservoirs to bolster reserves for the dry season. The Meteorological Department has reported that a monsoon trough is contributing to heavy rainfall in northeastern and eastern regions, with some areas in the northern, central, and southern regions also experiencing heavy rainfall.
Currently, large and medium-sized reservoirs hold around 54 billion cubic meters of water, which is 71% of their total capacity. By the end of the rainy season, this is expected to rise to 61.064 billion cubic meters, or 80% of capacity. In the Chao Phraya River basin, the four main dams have a combined water volume of around 16,000 million cubic meters, or 65% of their total capacity, indicating they can still accommodate additional water.
In the eastern region, reservoirs in the Eastern Economic Corridor are currently at 61% capacity, reflecting the significantly lower-than-normal rainfall in this area. The Royal Irrigation Department is managing water resources to meet various sectoral needs while keeping an eye on areas susceptible to heavy rainfall and potential flash floods.
To address flood risks, the department has prepared over 5,000 units of machinery and equipment, including water pumps and trucks, to expedite water drainage and mitigate impacts. Since May 1st, equipment has been deployed to 55 provinces, totaling 647 units, allowing many areas to return to normal conditions.
Mr. Witthaya has also instructed irrigation offices to closely monitor weather conditions, especially in areas with accumulated rainfall and flash flood risks. This includes overseeing water levels in the upper Chao Phraya River basin and adjusting drainage plans as needed. The department continues to prepare for late-season rainfall while conserving water for future use.