Monsoon rains to intensify into late September
Thailand’s National Water Resources Office (ONWR) has issued an urgent warning after emergency talks in Bangkok. A monsoon trough will sweep across the lower North, Central, East and Northeast until 16 September, bringing heavy downpours.
From 17–21 September the trough will shift south, unleashing severe rainfall in Bangkok and surrounding provinces. Adding to the peril, forecasters say one or two tropical storms could hit between late September and early October – a scenario that could push the system over the edge.
Dams at breaking point – emergency discharges ordered
Key reservoirs across the kingdom are now at or near full capacity. Officials confirmed water releases to prevent structural strain:
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Ubol Ratana Dam (Chi-Mun Basin): 67% full, daily release raised from 18m to 20m cubic metres.
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Huai Luang Dam (Northeast-Mekong Basin): 100% full.
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Nam Oon Dam: 90% capacity.
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Nong Han Dam: 98% capacity.
All three northeastern dams are spilling water to create buffer space for incoming rain.
Chao Phraya Basin on flood alert
Most worrying is the situation in the central basin feeding into the Chao Phraya River.
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Bhumibol Dam: 76% full.
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Sirikit Dam: 87% full.
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Chao Phraya Dam: already discharging 2,000 cubic metres per second.
Despite controlled releases, 138,100 rai (about 55,000 acres) of farmland and communities in five provinces face imminent flooding: Sing Buri, Ang Thong, Ayutthaya, Pathum Thani and Nonthaburi.
National Water Command Centre activated
In response, the government has set up a National Water Command Centre under emergency level-2 protocols of the 2018 Water Resources Act.
The centre will coordinate all releases and warnings. Crucially, if the Chao Phraya Dam’s discharge needs to rise above 2,000 cubic metres per second, prior approval from the National Water Resources Committee chairman will be required three days in advance – giving riverside communities time to prepare.
Will Bangkok be spared?
For now, officials stress they are holding the line. But with swollen dams, surging rivers and storms yet to come, the capital’s safety hangs in the balance. Bangkok’s flood defences – long tested by the Chao Phraya – could soon face their toughest trial in over a decade.