Chao Phraya River forecast: high tide and accumulated rainfall raise flood risk in Bangkok and neighbouring provinces

The National Water Resources Office (ONWR) has forecast that water levels along the Chao Phraya River near Phra Chulachomklao Fort and surrounding areas from October 3-6 between 16:00-18:00 hrs will coincide with high tides, reaching approximately 1.70-1.90 metres above mean sea level—around 0.20 metres above critical levels—due to a weakening southwest monsoon. 

Meanwhile, easterly and south-easterly winds continue to bring rainfall to parts of Thailand, further raising river levels and causing potential flooding in low-lying areas along the Chao Phraya, Tha Chin, and Mae Klong rivers, including communities outside embankments and temporary flood barriers in Samut Prakan, Bangkok, Nonthaburi, Pathum Thani, Samut Sakhon, Nakhon Pathom, and Samut Songkhram provinces.

ONWR has urged relevant agencies to:

• Monitor water levels closely, inspect the stability of riverside flood defences, and strengthen embankments in vulnerable low-lying areas. Authorities should also inform residents living outside embankments and temporary flood barriers in advance.
• Prepare machinery and equipment to integrate disaster response measures and assist affected communities immediately.
• Track high tide levels during this period and adjust water management plans for reservoirs, drainage gates, and spillways to respond appropriately.

Bangkok Governor Chadchart Sittipunt added that while rain bands have not yet reached Bangkok this week, rainfall is expected to increase next week. Special attention should be given to upstream dam releases, as current water levels are high—similar to the 2011 flood—at an estimated discharge rate of 2,500 cubic metres per second.

This release will raise water levels along the Chao Phraya on October 9-10. While the situation is not yet critical, it may affect communities outside the embankments, particularly areas to watch closely:

• Communities near Wat Thewarat Kunchorn
• Rice mill communities
• Certain points in Song Wat district
• Low-lying riverside areas prone to repeated flooding

Chadchart also warned of potential water seepage in some embankment locations.

For initial preparedness and assistance, Bangkok authorities have prepared over 200,000 sandbags for deployment to vulnerable points, and residents living outside embankments are urged to take extra precautions on October 9-10.