Cracks in Rayong reservoir wall trigger evacuation as flood risk persists

An emergency evacuation was ordered in parts of Thailand's eastern province of Rayong on Monday after authorities warned that a reservoir was at risk of failure, as heavy rain continued to raise flood and landslide risks across the country.

The Thung Khwai Kin Subdistrict Administrative Organization issued a notice, urging residents in potentially affected areas to leave immediately and move valuables to higher ground, after cracks were found in the wall of Khlong Ra-Ok Reservoir, also known as Khao Chuk Dam. Damage was also reported around the spillway.

Residents of Thung Khwai Kin and Nam Pen were among those urged to evacuate, with possible downstream impacts in Kong Din and Khlong Pun. Three temporary evacuation sites were designated at Wat Chumnum Sung, Chamnan Samakkhi Witthaya School and Wat Noen Sombun, according to the notice.

Local authorities said the reservoir had reached about 23.5 million cubic meters, or 117 percent of its capacity, with water continuing to spill over the structure. The outlet gates were opened fully to release water and reduce pressure on the reservoir.

The incident came as Thailand remained under widespread flood warnings following several days of heavy rainfall.

The Thai Meteorological Department forecast that rainfall would ease somewhat in Bangkok and surrounding provinces on Sept 28 and 29, but thunderstorms could still affect 70 percent of the area, accompanied by isolated heavy downpours. Heavy to very heavy rain remained possible in parts of the North, Central region and East, with flash floods, overflowing rivers and landslides possible.

The National Water Command Centre reported that Rayong recorded the country's highest rainfall, at 289 millimeters, while Kanchanaburi received 238 mm. Flood and runoff risks remained in 30 provinces, including Bangkok, Nonthaburi, Pathum Thani, Samut Prakan, Rayong, Chanthaburi and Trat.

In Bangkok, authorities continued operating drainage tunnels and pumping stations at full capacity. Flooding had affected dozens of roads, while several major canals remained at critical levels.

The government has also stepped up emergency relief. Deputy Interior Minister Worasit Liengprasit visited a temporary shelter in Bangkok's Bang Kapi district and ordered the deployment of a field kitchen and mobile water-purification units to provide food and drinking water around the clock.

Authorities are also preparing for recovery, including possible financial assistance and compensation for damaged homes and property, with the Department of Disaster Prevention and Mitigation coordinating applications with local agencies.

Small boats in the upper Andaman Sea and upper Gulf of Thailand have been advised to remain ashore through Sept 28. Waves could exceed three meters during thunderstorms, according to the meteorological department.

While rainfall may ease in Bangkok, authorities continue to warn that accumulated water, runoff and further downpours could keep flood risks elevated in several parts of the country.