Thai Industry Warns of Water Risks in Three Key Basins

The Federation of Thai Industries is closely monitoring three economically critical river basins—Chao Phraya, Mae Klong, and Eastern—warning that water hazards persist despite declining rainfall and raising concerns about impacts on manufacturing and logistics hubs. Prida Watcharuthetsagul, vice-president of the Federation of Thai Industries and head of the Water, Environment and Climate Change Institute, stated that although Thailand's rainfall is trending downward, water risks remain unresolved, as different regions face varying dangers from accumulated rainfall, runoff, upstream flows, drainage in main basins, and reservoir levels.

As of September 28, 2024, nationwide water reserves totaled 61,808 million cubic meters, representing 77 percent of capacity. The Western region holds 89 percent of its reservoir capacity, while the Eastern region holds 85 percent. The heaviest recent rainfall by area included Rayong at 289 millimeters, Kanchanaburi at 238 millimeters, Ranong at 135 millimeters, and Uthai Thani at 110 millimeters. The Meteorological Department expects rainfall to decline overall between September 29 and October 3, though heavy rain may still occur, particularly on the western side of the Northern and Central regions, requiring continued vigilance for accumulated rainfall and downstream water flows.

The Chao Phraya basin ranks among the highest-priority watch zones, as upstream water volume has increased. On September 28 at 6:00 a.m., station C.2 in Nakhon Sawan recorded a flow of 1,904 cubic meters per second, up from the previous day. The Chao Phraya Dam currently releases 1,950 cubic meters per second, with discharge rates under consideration ranging from 2,000 to 2,500 cubic meters per second, capped at approximately 2,300 cubic meters per second depending on conditions. Any increase in discharge could raise water levels in the central and lower basins, requiring continuous monitoring of the provinces from Chainat through Bangkok, particularly low-lying areas, riverbanks, and unprotected zones linked to production bases and logistics networks. The industrial sector should use data from station C.2, Chao Phraya Dam discharge rates, water levels at monitored stations, and station C.29 at Bang Thai as indicators for adapting response measures.

The Western region and Mae Klong basin remain under high alert due to accumulated rainfall, elevated reservoir levels, and upstream inflows. Kanchanaburi recorded the highest rainfall at 238 millimeters, while the region's reservoirs stand at approximately 89 percent capacity. The Irrigation Office 13 has warned of increased discharge through the Mae Klong Dam exceeding 1,500 cubic meters per second following rising water in the Khwae Noi and Khwae Yai rivers. As of 6:00 a.m. on September 28, the Mae Klong Dam released 1,313 cubic meters per second downstream, requiring continued monitoring of riverbanks and low-lying areas in Kanchanaburi, Ratchaburi, and Samut Songkhram, along with impacts on transportation routes and supply chains connected to the Central region.

The Eastern region, though showing improving conditions in some areas, requires ongoing vigilance due to high accumulated rainfall. Rayong recorded the highest precipitation at 289 millimeters, with regional reservoirs at approximately 2,695 million cubic meters, or 85 percent of capacity. Monitoring must continue across Nakhon Nayok, Prachuap Khiri Khan, Sa Kaew, Chachoengsao, Chon Buri, Rayong, Chanthaburi, and Trat, with particular attention to stream water levels, reservoir discharge, and impacts on communities, transportation, and industrial bases.

Other areas also face risks of flash floods and inundation according to national water resource alerts for September 26-30, covering the Northern, Central, Western, and Eastern regions, Bangkok and its surroundings, and parts of the Southern region, particularly hillside areas and river valleys. Prida advised the industrial sector to prepare accordingly.