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Fight To Keep Bangkok Above Water


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Posted

BANGKOK, Nov 7 — Each of the 51 submersible pumps at the Phra Khanong pumping station — the biggest of the facilities draining Bangkok — can at full throttle blast 173 cubic metres per second of water into a broad canal.

From there, the momentum propels the water into the Chao Phraya river 1km away.

Night and day, the pumps work, literally keeping Bangkok above water.

When the rain comes down and the river rises, Bangkok needs every last ounce of that horsepower. That is because much of the city of over 10 million people is below the level of the river.

The build-up of the urban infrastructure has constricted what used to be natural drainage.

Fifty years ago, for example, the Sukhumvit area in the heart of Bangkok used to be open rice fields and hamlets, drained by big and small canals, or klongs. Today, it is a dense urban sprawl — and in some places, narrow lanes become creeks in heavy rain as water pours into them from the higher plinths of the surrounding buildings.

The site of Suvarnabhumi International Airport was a wetland famously known as “cobra swamp” in Thai. The airport rests on giant sand-filled pilings buried deep in the ground.

A large part of Bangkok is also sinking, partly because the drawing up of ground water has emptied underground aquifers. Closer to the coast, just a few kilometres south, land subsided by 38cm between 1992 and 2000.

Further inland, in the more built-up areas, land subsided by around 4cm. Large parts of the city are below mean sea level.

With sea levels rising due to global warming, that puts many areas at risk from multiple factors. The worst scenario is a high tide coinciding with concentrated torrential rain in the north swelling the volume of water in the Chao Phraya, and more rain filling Bangkok's lanes with water. High tide, especially in November and December, can be felt up the river for a distance of over 50km.

“If the river is low we don't really need pumps,” said Sompong Wiangaew, deputy director of drainage and sewerage, who has been at the Phra Khanong station for 10 years. “But the level varies twice a day depending on the tide; the variation can be as much as 3m.”

At the most recent high-water mark — some three weeks ago on Oct 15 — the water in the Chao Phraya rose to 2m above sea level. The top of the flood wall is just 2.5m above sea level.

This year, the Bangkok Metropolitan Administration (BMA) spent 10.42 million baht (RM1 million) in preparing as many as four million sandbags to place in vulnerable areas to hold flood waters back.

After the last major flood in 1983, the city authorities enhanced the drainage system. The pumps at Phra Khanong were commissioned in 1984.

Today, 758 pumps like those at Phra Khanong, plus the canals, and a network of retention ponds, give nature — and the city — a helping hand in absorbing water and draining off excess.

There is little land left to dig new klongs, so the BMA is now forced to lay large concrete drains underground.

Essentially, 77km of dykes and flood walls along the Chao Phraya and major klongs, whose waters are higher than the city, stand between Bangkok and the floods.

The pumps push the water from the city into the Chao Phraya and “it cannot come back because of the wall”, explained Jessada Chantarapranbha, a civil engineer with the BMA. The flood wall along the river has a built-in “freeboard” or safety margin, said Jessada.

“By 2050, the sea level will increase by 12.3cm, and subsidence will be around 30cm. Combined, it will amount to 42cm. But we have a 70cm freeboard now,” he said, as he pored over a drainage system map. “However, the 2050 figure is just a prediction,” he added. “We are not sure if it is going to be better or worse.”

The map shows the dykes, pumps and klongs on which Bangkok increasingly depends to stay functional.

The water from a vast swathe of Bangkok is channelled from the klongs to the submersible pumps that are mostly clustered on the east bank of the Chao Phraya. Steel grates filter out most large solid waste, which at Phra Khanong amounts to 20 tonnes a day.

A total population of almost 100 million in Bangkok, Mumbai, Kolkata, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai and Yangon are at risk from climate change, the Intergovernmental Panel on Climate Change said in 2007.

“The mega-deltas of Asia are vulnerable to climate change and sea level rises that could increase the frequency and level of inundation... putting communities, biodiversity and infrastructure at risk,” the panel said.

“This impact could be more pronounced in megacities... where natural ground subsidence is enhanced by human activities, such as in Bangkok.”

Bangkok was once mostly wetland. It is not an exaggeration to say that perhaps in another 50 to 100 years, nature will reclaim its lost world. — Straits Times

http://www.themalaysianinsider.com/lite/ar...es.php?id=42619

Posted (edited)

What sea levels are rising? hogwash dont tell me Tuvalu and the Maldives, huh no sinking there then!! Plenty of funding ensues though!

Oh sorry I knew it was all a joke when I read this bit

"A total population of almost 100 million in Bangkok, Mumbai, Kolkata, Dhaka, Guangzhou, Ho Chi Minh City, Shanghai and Yangon are at risk from climate change, the Intergovernmental Panel on Climate Change said in 2007"

Edited by yabaaaa
Posted

thanks for that churchill, some good info there, although this topic has been addressed in countless thai visa threads.

Imagine the oceans of the world being littered with all the filth and crap from bangkok and its surrounding areas :D , as no doubt the thais will pick up their rubbish as they leave in their canoes :)

Posted

Stop being brainwashed http://libertyscott.blogspot.com/2009/10/m...on-climate.html

Christopher Brooker in the Sunday Telegraph notes that the President of the Maldives was sent an open letter from Dr Nils-Axel Morner, the former head of the international Inqua Commission on Sea Level Change. It says "that his commission had visited the Maldives six times in the years since 2000, and that he himself had led three month-long investigations in every part of the coral archipelago. Their exhaustive studies had shown that from 1790 to 1970 sea-levels round the islands had averaged 20 centimetres higher than today; that the level, having fallen, has since remained stable; and that there is not the slightest sign of any rise. The most cautious forecast based on proper science (rather than computer model guesswork) shows that any rise in the next 100 years will be "small to negligible"."

So it is a monumental fraud to scare the world into thinking the Maldives will be swamped.

Posted

http://globalwarmingtrends.blogspot.com/20...underwater.html

"The article does admit that the sea level rise in Bangkok is about .1 inches per year, the same as the global average. As we have already discussed in a previous article, this rise is not above the normal expected increase. Sea levels have been rising since the last ice age, and there has not been any acceleration in that rate since the 1950s."

Posted

Actually, global cooling is underway (low sunspot activity) and if this keeps up we may be headed for at least another "little ice age", with its concomitant drop in sea-levels, before anything else. Nothing to worry about. Ice ages are the norm for this planet...

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