Residents talk to a policeman as floods advance into central Bangkok, Thailand, October 26, 2011.
Residents talk to a policeman as floods advance into central Bangkok, Thailand, October 26, 2011.

Authorities in Thailand are turning to desperate measures as they try to prevent the Chao Phraya River from overflowing its banks and inundating central Bangkok.

The Thai navy has deployed a fleet of ships to the Chao Phraya and other rivers, where they are using their propellers to try to speed the flow of water through the city to the sea.

Navy Captain Prasert Chanprapak said he believes the effort is helping.

"It helps a lot. From what I calculated, usually the water in Klong Lat Po is around 500 cubic meters per second. With more than 10 vessels here, it can increase the water flow to more than a thousand cubic meters per second,'' he said.

He said with 10 vessels in one location, he believes the flow of water has been doubled.

Bangkok city Governor Sukhumbhand Paribatra said the Chao Phraya River may crest overnight Wednesday. If it does, he said water will overflow a barrier at a canal on the city's northern border.

For her part, Prime Minister Yingluck Shinawatra said she is no more than 50 percent certain that the city will be spared, despite the navy efforts and constant reinforcement of the embankments.

In an address to the nation Tuesday evening, she said that if the embankments fail, the city could be flooded to a depth of 1.5 meters in places.

"The flood water levels in Bangkok, due to variation of the plains' altitude, could range from 10 centimeters to 1.5 meters. We will control the runoff to allow only the least water to enter Bangkok, to flood for the least number of days, and will stop the flow of water in the quickest possible way, by using all the drainage means we have," said Yingluck.

If that happens, she said, authorities will use all available means to see that the water drains off as quickly as possible. Officials say the most critical moment will come at 7 a.m. local time Thursday when an unusually high tide coincides with a surge of floodwater from the north.

Yingluck's warning sparked another wave of panic buying by residents, who have emptied store shelves of supplies. Many are frustrated and confused after a series of sometimes contradictory statements by national and local officials.

Resident Wanthawat Songsirisri said he doubts the authorities can protect the city.

"The government has tried many methods, but the volume of water that they are trying to block is too large. The map from TV news showed that the Chao Phraya River is as tiny as a straw, but there is just too much water flowing through it. I don't think they [the government] can handle it,'' he said.

He said he thinks the volume of water descending on the city from central Thailand is just too much.

The government has ordered a five-day holiday beginning Thursday to allow residents to prepare for the worst or leave the city.

Some information for this report was provided by AFP and Reuters.