Thailand’s Royal Irrigation Department reported on 9 June 2025 that steady rainfall has increased water inflows to national reservoirs, prompting coordinated management efforts to mitigate downstream impact during the rainy season.
Recent continuous rainfall across several regions of Thailand has contributed significantly to water inflows into the country’s reservoirs, particularly benefiting major and medium-sized storage facilities. As of 9 June, national reservoir storage had reached 43,246 million cubic meters, accounting for 57 percent of total capacity, according to the Royal Irrigation Department’s Smart Water Operations Center.
The data also showed that these reservoirs are still capable of receiving an additional 33,245 million cubic meters, or 43 percent of their full capacity. The four major dams in the Chao Phraya River Basin—Bhumibol, Sirikit, Kwae Noi Bamrung Dan, and Pasak Jolasid—currently store a combined 13,158 million cubic meters, which represents 53 percent of their total capacity. These dams can still accommodate 11,713 million cubic meters of water.
From 1 May to 9 June, large reservoirs nationwide recorded over 3,800 million cubic meters of runoff. River water levels in northern Thailand’s major tributaries remain within normal ranges. In Nakhon Sawan province, the Ping River near Banphot Phisai District is about 4 meters below the riverbank, and the Nan River in Chum Saeng District is 6 meters below. These rivers converge to form the Chao Phraya River at Pak Nam Pho, where water flow at station C.2 in Mueang Nakhon Sawan District measured 710 cubic meters per second—still approximately 7 meters below the riverbank.
The water retention strategy follows the 2025 rainy season management plan, which takes into account rainfall levels, watershed areas, and each reservoir’s capacity. The goal is to control runoff, reduce flood risk downstream, and ensure adequate water supply for the following dry season.
Officials emphasized that the current measures are part of coordinated monitoring and management efforts during the rainy season. The irrigation department and related agencies are actively tracking weather conditions and maximizing the use of irrigation systems while continuing public communication on water conditions in line with government policy.
