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Flood?


radioman
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Life as normal Chez 'Kong, stayed bone dry at the last high tide, plenty of fresh food in Local market all roadside food stands operating as normal, drinking water delivered to local convenience stores, taxi's motor cys's and Song Taew as usual etc. Probably pop out to Patpong tonight.

 

Two more high tides to go and if we do get floods it will probably only reach curb height and be gone within a couple of hours which is on par with a torrential downpour so no concerns at all.

 

The soon to be ex-wife's house is under 1.5 Meter and Rising in Lam Lu Ka and I don't give a Shit :spin: :spin:

Was that you on the TV news...pissing in the klong by the x's house...just to make sure there was enough water there :dunno:

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After watching, listening, and reading for two weeks, I have reached the following conclusions about the potential for Bangkok to flood:

 

1. Bangkok is a shallow bowl. It has flood-walls to isolate itself from the ocean, and from the Chao Phraya River - both of which are slightly above Bangkok's elevation. Typically, these barriers reach a level 4-5 meters above Bangkok elevation, and - typically - 2.5 meters above sea level.

 

2. Bangkok is criss-crossed with an extensive network of canals (Khlongs), all of which eventually empty into four or five major khlongs. These major khlongs carry water to the Chao Phraya River, or to the ocean. But - at the discharge end - gravity cannot project water over the flood-walls. So - massive pumping stations are located at the discharge ends of the major khlongs, to pump water over the barriers.

 

3. One major function of the khlong network is to drain rainwater out of Bangkok - and the network performs this function well. But - even within and throughout the khlong network, there is insufficient gradient to naturally project water forward toward the discharge end. So - there are many pumping stations, which must be working aggessively, to keep water moving toward the discharge end.

 

4. We now have a situation where a massive amount of water has accumulated in an arc around Bangkok - covering perhaps 150 degrees, centered on north, and extending back between 100 and 200 km. A very good overview of the magnitude of this problem can be seen in this helicopter footage: http://youtu.be/HhMp8AnhDF4

 

5. Because of the weak elevation gradient across central Thailand, this mass of water is not likely to be going anywhere quickly. It will mostly have to slowly drain off via the Chao Phraya and a couple of smaller rivers. Bangkok does lie between the flooded area and the ocean. Many flooded communities seem to think that the key to draining their area is for Bangkok to simply accept being flooded - as that will expedite drainage from their area. They think that this approach is being blocked by conscious human decisions by Thai government officials.

 

6. In reality, water can escape Bangkok, and project itself into the river or the ocean no faster than the pump stations at the discharge ends can pump water over the barriers - and even this process will not work if river depth is elevated, or during high tides. And - water can move through the greater Bangkok khlong network no faster than all the intermediate pumping stations can project it forward. I suspect that no human action is presently blocking drainage from up north. The simple urban typography of Bangkok is such that water cannot penetrate far based on just gravity. To the extent that it can penetrate on its own, it has already done so - as at Vibhavadi Road - but the water eventually drains away into the storm sewers (and ultimately into a khlong), and projects no further. Without active human intervention, it is unlikely that floodwater will further penetrate Bangkok.

 

7. In the absence of rain falling on Bangkok, there is a LOT of reserve capacity in the khlong network to drain water southward. The trick is to get floodwater from up north into the khlong network, at a rate of flow that does not overwhelm that network - and which can be shut off during high tides.

 

8. Ignorance and poor government communications have created two bad perceptions:

 

a. People up north need to understand that flooding Bangkok will not help them. I don't know the real computations, but if you flooded the entire surface are of Bangkok up to equilibrium level with the surrounding flood-zone, I suspect that water levels in the flood zone would only fall perhaps one cm (or less). That water would not then drain further - it would just sit there, contained by the southern and western flood containing walls of Bangkok. It thus makes no sense to allow water into Bangkok at a rate faster than the discharge pumps can pump it over the retaining walls.

 

b. Politicians are - in general - not blocking natural water flow. Urban topography is blocking water flow - due to the shallow drainage gradient of the flood waters. Other than natural flow via the Chao Phraya and other small rivers, it will take conscious human intervention to move water through Bangkok. At present, intervention by community activists - who are misinformed, but fearful - is blocking optimum flow through the khlong network - flow that could be smoothly projected through the system.

 

9. The only proposal to increase drainage that has any technical merit is the announced plan to cut a new water channel through the urban topography on the East side of Bangkok. If sufficient pumping resources are included, then this plan would indeed contribute to draining additional water from up north. It is up to government officials to carry out a cost/benefit analysis to determine if the benefits for up-country flooding victims justify creating a fresh swath of urban victims.

 

 

Bottom line: The Governor of Bangkok is generally correct. There is unlikely to be further significant flooding in Bangkok, unless it is deliberately created. Riverfront areas will continue to receive overflow from the flood-walls for a couple of hours during high tides, outlying areas of Bangkok will remain flooded as encroaching water dribbles away through the storm drain network, and any sustained heavy rain that falls on Bangkok - particularly during high tide - will cause temporary flooding. Otherwise, life in Bangkok could more or less be "business as usual."

 

The flooded arc above Bangkok served as the "breadbasket" of Bangkok - with a nightly flow of tens of thousands of small trucks bringing fresh produce into Bangkok to feed 10-12 million people. That bread-basket - out to several hundred km - is basically wiped away. Fresh produce will mostly disappear for the rest of 2011 - or be very expensive.

 

It would be nice if the story above could be coherently explained to the public - so as to allay fears, and secure better cooperation.

 

Cheers!

SS

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They still wouldn't believe it. Some of the red shirts positively hate Bangkok and its population. There were TV interviews of red shirt villagers last year when the city was being torched. Even women would screech that it served them right! If Bangkok wouldn't give them everything they demanded, it deserved to be burned.

 

You are dealing with true believers with an average IQ of around 90. Rots of ruck explaining anything they don't want to hear. Even now some red shirts have been demanding that Bangkok residents be taxed to pay for flood damages outside the city. Bangkok's people are greedy and selfish and refuse to give the villagers what "they should have" - money for nothing, money the city folks worked for.

 

TIT :dunno:

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BTW I saw that food from some street vendors has gone from 25 or 30 baht to 35 and 40 already. Veggies in the market were comparatively expensive before the floods, even more so now. The shelves are still bare in the groceries and 7-Elevens ... haven't been able to get resupplied because the roads to the warehouses are flooded. The Army has offered to deliver for them.

 

p.s. Soupy, you should send that to the Post or Nation. I'm sure they would publish it, especially The Nation.

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I have always heard it.

 

<< Many well-populated places in the world are below sea level. About a third of the Netherlands including Schiphol Airport is below sea level. So too are the Jordan River and parts of many coastal cities including New Orleans and Bangkok. >>

 

http://geology.com/below-sea-level/

 

 

<< The arithmetic gives Bangkok little cause for optimism. The still expanding megapolis rests about 3 1/2 to 5 feet above the nearby gulf, although some areas already lie below sea level.

 

The gulf's waters have been rising by about a tenth of an inch a year, about the same as the world average, says Anond Snidvongs, a leading scientist in the field. But the city, built on clay rather than bedrock, has also been sinking at a far faster pace of up to 4 inches annually as its teeming population and factories pump some 2.5-million cubic tons of cheaply priced water, legally and illegally, out of its aquifers. This compacts the layers of clay and causes the land to sink. >>

 

My link

 

Bangkok will sink by 2025

 

Bangkok sinking

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