BANGKOK, Thailand -- Floods have smothered much of Thailand, killing at least 317 people and prompting Bangkok to surround itself with makeshift walls, leaving those outside the perimeter to suffer from diverted water, reminiscent of medieval times when people dug moats and sealed off their fortress cities against plague, war and other calamities.

"We have been doing everything we can, but this is a big national crisis," Prime Minister Yingluck Shinawatra told reporters on Wednesday (Oct. 19).

"I'm begging for mercy from the media here," she said, after heavy criticism for her poorly coordinated response to the floods.

Bangkok is now a virtual island under siege from a relentless flow of brown water, strewn with garbage and chemicals, after three months of widespread monsoon rains and increasingly swollen rivers, all flushing alongside the capital and draining into the nearby Gulf of Thailand.

Many U.S. and other foreign companies -- which were lured to this tropical Southeast Asian country to profit from workers' low wages and other cheap costs -- have found their modern factories and warehouses devastated because they are located outside Bangkok's survival-of-the-fittest flood walls.

Distraught investors watched in dismay as swirling liquid drowned several sprawling, investor-friendly, low-lying "industrial parks" after breaching insufficient barriers.

The worst-affected industrial zones are 50 miles north of Bangkok where three rivers converge at Ayutthaya, which was founded in 1350 and became an opulent capital before it was abandoned in 1767 because elephant-riding troops from Burma invaded and destroyed it.

Multinationals which suspended or slowed operations due to the floods in Ayutthaya included Canon, Ford, Honda, Isuzu, Nikon, Seagate Technology, Sony, Toyota and Western Digital.

"Production of hard drives in its facilities in Thailand will be constrained in the current quarter due to the local severe flooding," California-based Western Digital said in a statement.

"I think this is the biggest loss for Japan's overseas investment," Japan's ambassador to Thailand, Seiji Kokima, was quoted as saying on Tuesday (Oct. 19).

More than 14,000 factories have been wrecked by floods across 20 provinces, displacing more than 660,000 workers, according to the Labor Welfare Department's director-general, Arthit Ismo.

"In Thailand, most of the affected areas in the north remain accessible only by boat and thousands of people are reportedly stranded," including more than 54,000 people huddling in 912 emergency shelters, the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said.

"In Bangkok, as another wave of massive runoff flowing from the north is expected on October 20, the army, different government agencies and volunteers are working harder to reinforce the six-kilometer (3.7-mile) -long flood wall on the edge of the city," OCHA said on Wednesday (Oct. 19).

At least "200,000 sandbags are needed to reinforce the barriers around the city."

Thailand is drained from the north to the south by a Florida-sized central Chao Phraya River Basin.

That southward route flows past Bangkok, which is a bustling port on the Chao Phraya river just north of the Gulf of Thailand.

Anarchy erupted at some sluice gates and dikes where angry people refused to obey government orders to protect Bangkok by diverting floodwaters into their neighborhoods and farms.

The government's controversial, Darwinian strategy of sacrificing the countryside and outer suburbs to save Bangkok had been used in previous floods despite an outcry from thousands of intentionally flooded victims.

"I am the housekeeper for the whole of Bangkok, so I cannot allow flooding in any part of the city without trying to stop it," Bangkok's governor, Sukhumbhand Paribatra said on Tuesday (Oct. 18).

A bounty was placed on the kill or capture of crocodiles which swam away from various cities' holding pens when water breached their walls.

Officials warned the public about how to protect themselves against deadly creatures lurking throughout the country's flood-stricken areas.

"Avoid wading through water or walking on water-logged bridges at night, since snakes and other reptiles may be hiding there and vibration from walking can frighten and prompt them to attack you," the Bangkok Post said.

"If the rescuers are too busy or far away, you may have to beat them to death, but if it happens to be a big snake, cover it with blankets and wait for a professional hand to arrive and deal with the problem."

The past three months of rain have created a vast, inland, freshwater sea in central Thailand, and when the floodwater approaches Bangkok to drain, most of the water is being diverted to flow around the capital on either side.

Haphazardly reinforced flood walls, sluice gates, canals, dikes and other emergency efforts were erected to surround Bangkok, but some northern and eastern suburbs were flooded, and the Chao Phraya river also submerged some nearby streets.

Thailand's main Suvarnabhumi International Airport was vulnerable because it is on Bangkok's eastern outskirts and built on swampland.

Despite the mayhem, life in much of Bangkok has remained mostly normal, with people shopping in lavish malls, dining out, and going to work while worriedly stocking up on essential items just in case.

Nerves became jangled after government officials repeatedly issued conflicting updates, alternately advising residents of Bangkok and other cities to evacuate, then assuring them they were safe, and then announcing that more sandbags were desperately needed because flood walls were crumbling.

Much of Bangkok is flat and only about six feet above sea level, resulting in a slow runoff during floods, especially when the Gulf of Thailand's high tides swell against the nearby coast.

Thailand's current floods are the worst since October 1962, when tropical storm Harriet ripped across the southern Isthmus of Kra, killing more than 670 people before sweeping toward the Andaman Islands.

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Richard S Ehrlich is a Bangkok-based journalist who has reported news from Asia since 1978. He is co-author of Hello My Big Big Honey!, a non-fiction book of investigative journalism. His web page is

Asia Correspondent

(Copyright 2011 Richard S Ehrlich)