As a result, provinces adjacent to the river would continue to suffer a flood crisis until at least November, Royal Irrigation Department chief Samart Choknapitak warned yesterday.

Ayutthaya, which has already been hit hard, faced an even greater burden, he said. The department would soon be forced to divert Chao Phya overflow in the pro-vince to save Bangkok, Non-thaburi and Pathum Thani from flooding, he said.

"The flood situation in the Chao Phya River basin is critical and is bearing the long-term brunt this year. It is expected to continue until at least November," he said. The most critical period is between yesterday and Friday, when Gulf of Thailand sea levels will peak for this year.

The diversion was proposed by flood-management experts at Kasetsart University and agreed on by the Chao Phya River basin long-term flood-management working committee headed by Privy Coun-cillor Sawas Watthanayakorn.

Farmland was capable of absorbing river overflow that had exceeded that of four years ago and was nearing an 11-year-old record.

Samart said many thousands of rai of farmland at Bang Ban district would have to be sacrificed to save Bangkok and the two neighbouring provinces.

"If drainage is not done within the next few days, the Chao Phya will swell 13 centimetres over flood embankments along the river," he warned.

Yesterday in the capital, Chao Phya River levels at the Memorial Bridge reached 2.5 metres. Floodwaters would reach 2.63 metres without upstream diversion. With it, they would fall to 2.4 metres.

The height of flood prevention barriers would be increased to 2.70 metres to cope with extra volume. Sandbags would be positioned along banks at the Arun Amarin area of Thon Buri.

Many parts of Bangkok were flooded after yesterday's heavy rain. Tunnels at the Huai Khwang and Suthisarn intersections on Ratchadaphisek Road were impassable, while areas of Huai Khwang were heavily flooded.

Several sections of Lat Phrao Road were inundated, including its intersection with the Ekamai-Ram-Indra expressway, causing heavy congestion. One radio report claimed more motorists were on the roads yesterday after petrol prices fell.

Both outbound and inbound Phaholyothin Road in northern Bangkok were flooded - notably its junction with Vibhavadi-Rangsit Road near the National Monument at Rangsit.

Other flooded arteries were Srinakarin, Rama IV, Ramkhamhaeng, Sukhumvit 71, Ekamai, Pradit Manutham and Pridi Banomyong.

Storms have now affected 45 provinces across the country since late August. Some 17 provinces are still experiencing floods caused by Typhoon Xangsane last week.

The official death toll reported by the Department of Disaster Prevention and Mitigation reached 39 while more than two million people had been made homeless or affected in some way.

Total financial losses were estimated at more than Bt236.6 million. A 1784 hotline has been set up for emergency calls.

The irrigation department's Samart explained reservoirs at the Bhumibol, Sirikit and Pasak Jolasit dams - located in Tak, Uttaradit and Lop Buri provinces respectively - were at capacity. The dams were structurally safe.

Privy Councillor Sawas earlier met with leader of Chao Phya provincial heads and Bangkok Governor Apirak Kosayodhin to assess immediate flood-management measures.

Weather forecasts reported average rainfall was 15 per cent greater than last year, and heavy rain was likely across the country until at least Thursday.

Apirak said city floodwaters would be pumped into the river only at low tide. Suvarnabhumi Airport was not expecting flooding.

However, future planning would need to be adjusted to prevent flooding in nearby communities in the long term, according to Interior Ministry Department of Public Works and Town and Country Planning director-general Thirawat Kullawanich.

He said the department would need to ensure drainage took floodwater rapidly away from the airport to the Gulf. Canals used to divert water would need to be dredged or widened.

Town-planning policies and regulations governing construction around the airport would need to be tightened. Landfills would be strictly monitored to ensure canals and drains were not blocked, Thirawat said.