Chiang Rai – On Monday, Mae Sai District updated the progress of dredging the Ruak and Sai rivers in a joint project between the Royal Thai Army’s engineering unit, and Myanmar authorities.
Work began on 18 April 2025 and is scheduled to finish by 20 June 2025. The goal is to get ready before the monsoon season starts.
The main aim is to help water flow more easily along both rivers, covering a total length of over 44.8 kilometres. The Third Army Area is handling a 14-kilometre stretch of the Ruak River.
The engineering corps is working on another 18 kilometres. Myanmar is responsible for dredging a 12.8-kilometre section of the Mae Sai River.
Alongside dredging, teams are building flood barriers in Mae Sai’s economic zone. This area has faced flash floods and mudslides in the past years. The new barrier will run for about 3,600 metres, with 2,193 metres already under active construction.
The route starts at the Thai-Myanmar border, crosses the First Thai-Myanmar Friendship Bridge, and ends at the irrigation sluice gate.
The barrier is designed for quick set-up and strong flood protection before the rainy season. It uses a mix of structures based on what each area needs. These include riverbank walls made from concrete piles, reinforced concrete barriers, and strengthened earth embankments using big bags.
There are also custom defences for riverside homes in Mae Sai, such as steel plates to block water entry and pre-made concrete barriers.
Both the dredging and the new flood defences should finish by mid-June. This will give Mae Sai residents confidence that the area is better prepared for floods this year.
Gold mining in Myanmar’s Shan State, particularly in the Mong Hsat District along the Sai River, has been identified as a major cause of severe flooding and environmental damage in Mae Sai, Chiang Rai, Thailand.
A Thai government study from October 2024 found that large-scale mining operations, primarily by the United Wa State Army (UWSA) and junta-aligned Lahu militias, have led to significant sediment buildup and pollution in the Sai River.
Thailand and Myanmar are now dredging the Rauk and Sai Rivers and building embankments, but experts call for addressing upstream mining and improving flood prevention plans, as Mae Sai lacks adequate measures.
