The Royal Irrigation Department is continuously monitoring the water situation, managing balanced water resources in the Chao Phraya Basin, and preparing machinery and equipment to support risk areas in anticipation of the 2026 rainy season.
On 20 May 2026, the Royal Irrigation Department's Smart Water Operation Center (SWOC) reported the current water situation as of 19 May 2026. Large and medium reservoirs nationwide hold a combined volume of approximately 43,621 million cubic meters of water, representing 57% of their total capacity, and can store an additional 33,133 million cubic meters. Specifically, the four main dams in the Chao Phraya Basin (Bhumibol, Sirikit, Kwae Noi Bamrung Dan, and Pasak Chonlasit) contain a total of 13,483 million cubic meters, or 54% of their combined capacity, and can accommodate another 11,388 million cubic meters.
Regarding the Chao Phraya Basin water situation at 06:00 on 20 May, the water flow at station C.2 in Nakhon Sawan Province measured 563 cubic meters per second. Combined with inflows from the Sakae Krang River and its tributaries, the total volume available for management above the Chao Phraya Dam is 577 cubic meters per second, which is allocated into the irrigation system for various areas as follows.
The remaining water is released through the Chao Phraya Dam at a rate of 130 cubic meters per second, which will be maintained consistently and currently does not affect downstream areas.
Close monitoring of the water situation and weather conditions reveals that the cumulative rainfall nationwide from 1 January to 17 May 2026 totals 212.4 millimeters, which is 78.8 millimeters below normal, or 27% less than average. Several regions continue to experience below-normal rainfall, especially the eastern side of the southern region with 49% below normal, and the central region with 41% below normal. To prepare for potential impacts on the public and farmers, precautionary measures are in place.
The Royal Irrigation Department is continuously tracking rainfall and water resources and planning water management to maximize benefits, aligned with weather conditions and potentially variable rainfall throughout the season. This aims to minimize impacts on people across all areas. At the same time, machinery and equipment are being readied to assist flood-risk areas during the rainy season. The department strictly follows the 2026 rainy season response measures to mitigate effects on the public as much as possible, in accordance with directives from Mr. Suriya Jungrungreangkit, Minister of Agriculture and Cooperatives.