Thailand has approved the Chao Phraya 2 canal, a flood diversion project of more than 270 kilometres that will cut a new path for floodwater across nine provinces and out to the Gulf of Thailand. According to ASEAN NOW, the cabinet approved the project on 14 October 2026, with the Royal Irrigation Department as the project owner and a total investment of about 160 billion baht, including land acquisition costs. Construction is scheduled to run for eight years, from 2027 to 2034.
How the Chao Phraya 2 canal will work
According to ASEAN NOW, the work is divided into two main sections. The first section will widen existing canals between Chai Nat and the Pa Sak River, covering 134 kilometres at a budget of 38.092 billion baht. The second and larger section involves digging a new canal of 135 kilometres from the Pa Sak River to the Gulf of Thailand, budgeted at 98.625 billion baht and reaching up to 170 metres wide in places.
The new section will begin at Roeng Rang subdistrict in Sao Hai district, Saraburi, according to the same report. It will pass through Saraburi, Ayutthaya, Nakhon Nayok, Chachoengsao and Samut Prakan, on a route about 52 kilometres east of Bangkok. The plans also include weirs, smaller canals linking to the Rapeephat Canal, and paved roads running along both banks, so floodwater can reach the sea more efficiently instead of building up in the lower basin.
Land is a major part of the engineering challenge. Authorities expect to acquire about 16,208 rai of land, roughly 2,593 hectares, according to ASEAN NOW. About 2,600 households will be affected, and 21.794 billion baht has been allocated for compensation.
Why this flood scheme matters now
The Chao Phraya basin is the economic heart of Thailand, carrying runoff from the north and centre of the country through Bangkok to the sea. This year, severe flooding in the capital has renewed public anger about long term protection, and a Young Post report on the Bangkok floods noted that the cabinet plan is intended to divert floodwater away from the capital and relieve pressure on the river. The Asian Development Bank said on 14 October 2026 that recent flooding has underscored the need for long term solutions that protect communities, livelihoods and economic activity in the basin.
Supporters of the Chao Phraya 2 canal argue that a purpose built diversion gives engineers a second outlet when the main river is already full. Instead of relying only on the existing channel through densely built areas, flood managers would be able to send part of the flow eastwards to the Gulf, reducing the peak that reaches the lower river.
The scheme has also drawn scrutiny. Reporting on Bangkok Post coverage said a water management expert has questioned whether the project was designed primarily to protect Bangkok, and raised questions about its route, cost, environmental impact and impact on affected communities. Those questions are common on diversion canals of this scale, where the benefits are spread across a basin but the land and environmental costs fall on specific districts along the line.
What happens next
The next stage is preparation rather than excavation. According to the Thai News Agency account carried by Thailand News Gazette, the project will need an environmental impact assessment and public consultations, along with detailed design, before the main construction period begins in 2027. Land acquisition and compensation for the affected households will also have to be settled section by section.
If the programme holds, engineers will spend eight years widening old canals, digging the new eastern channel, and building the weirs, link canals and bank roads that turn a line on a map into a working flood system. For readers in Nepal, the lesson is familiar: the hardest part of flood engineering is rarely the concrete. It is choosing a route, paying fairly for land, and finishing the whole system, because a diversion canal only works when every link from intake to sea is complete.
Sources: ASEAN NOW, Chao Phraya 2 canal approved to tackle flooding and Asian Development Bank, ADB Joins Effort to Advance Lower East Chao Phraya Initiative