High tides expected for nine days, Bangkok and six provinces on alert for flooding

The Office of National Water Resources (ONWR) issued a warning on Tuesday regarding high tidal surges in the Chao Phraya River area. According to the Hydrographic Department, tides are expected to peak between December 4-12, 2025, with water levels reaching approximately 1.70–2.00 meters above mean sea level at Phra Chulachomklao Fort and nearby areas between 05:00 – 12:00 daily. These tides will be approximately 0.30 meters higher than the critical water level.

The rise in sea level is due to an eastern wind system moving into the Southern region and the Gulf of Thailand, which will raise the tide levels. Additionally, water flowing from upstream areas will further contribute to the high tide, causing the river water level to rise, resulting in flooding of low-lying areas along the Chao Phraya River, Tha Chin River, and Mae Klong River. This includes communities outside of flood protection dikes and temporary embankments in areas without permanent flood defences (known as “gap areas”) in Samut Prakan, Bangkok, Nonthaburi, Pathum Thani, Samut Sakhon, Nakhon Pathom, and Samut Songkhram.

In preparation for the upcoming high tides, the ONWR has urged all relevant agencies to take the following actions:

1. Closely monitor the water situation, check the stability of river flood protection structures, and strengthen embankments in flood-prone low-lying areas. Publicise information and alert residents living in areas at risk from flooding outside the flood protection dikes and temporary embankments.
2. Prepare machinery and equipment to support immediate assistance and reduce the impact on affected residents.
3. Monitor the tidal surge during the specified period and adjust the management of water from reservoirs, drainage dams, and sluice gates to align with the situation.

The ONWR is closely monitoring the situation to ensure effective flood management and minimise the impact on affected communities.