Floodwall Planned For Chao Phraya River: Thailand

[cloudhopper]

Last year, the floods covered about 100 km square to a depth of a metre (on average). Now they want to build flood walls along the river to contain the floods.

The flood walls will need to be a hundred metres high.

Posted with Thaivisa App http://apps.thaivisa.com

Fortunately 100m would not be required.

[ResX]

Last year, the floods covered about 100 km square to a depth of a metre (on average). Now they want to build flood walls along the river to contain the floods.

The flood walls will need to be a hundred metres high.

Posted with Thaivisa App http://apps.thaivisa.com

There is something about flood flows that an ordinary man cannot see. While a 1in 50 years flood flow for the entire chao Pharaya catchment is about 17billion cubic meter of flood flow that falls in 7 days or 28,100m3/s (Average =2,200m3/s), there are instances that the instantenous flood flows could be as high as 130,000 to 150,000 m3/s! They could last for 8 hours. How big the tunnel size to deal with 28,100 m3/s, 130,000 m3/s? Let me try to estimate. For the same depth, they are about 15 and 75 folds wider than Chao Pharaya river respectively. Taking average wide of the Chao Pharaya is 500m to transport average flow 2200m3/s for 300km, then total water surface requires is 150km2. For 15 folds higher flow Thailand needs 2250km2 of water surface area. To me it looks more like a reservoir than a tunnel.

Whatever option Thailand is going to implement I wish to remind that the critical succes factor is centered around the dams operations.

[maidu]

Over the past decades, hundreds of billions of baht have been spent on flood prevention. Yet, 2011 was the worst ever, and it didn't even have the most rainfall. Walling in the Chao Praya river won't work, even if the wall starts up above Ayutaya. They'll have to wall tributaries and klongs also - those which drain in to the main river.

Hate to say it, but pouring hundreds of billions more to try and keep Bkk dry is like pouring money down the ......(you guessed it). Except with Bangkok, there is no drain. Already the walls are purportedly 10 M above sea level (at highest tides?).

I realize Bkk has been a gargantuan investment, but so was the Titanic. Now, it's time to seriously consider moving Bkk people and services to higher ground - as the recently flooded manufacturing companies should also be doing. Satellite cities are better investments than 15 meter high walls stretching for hundreds of Km's.

Even with the walls, the water has got to go someplace. Plus, when you wall out water, the same walls will wall in dirty water, when the levees eventually get breached. If there are giant pumps, they each have to have dedicated power cables. They can't be on the public grid, because they'd get affected by inevitable short circuits. Additional tens of billions of baht for dedicated power cable contracts - 60% of the revenue going in to big shots' pockets.

[maidu]

Fukushima had trouble with non-functional pumps, and the the Japanese are miles ahead of Thais in terms of tech, emergency equipment and expertise. Plus Fukushima's land mass is tiny compared to Bangkok's. On an earlier thread here in ThaiVisa (about Bkk's recent flood) there was mention of giant pumps in the city sitting idle. Why? I don't know, do you? Maybe they got packed with trash, or maybe there wasn't sufficient power getting to them.

[ResX]

Let me share how we did it without a need for additional tunnel. We have a power generation & flood control reservoir, and probably rank second of third the largest in SEA in term of total storage volume.

Name of the reservoir : We name it R

Total storage = 15billion cubic meter (Greater than Bhumibol & Sirkit)

Regulated strorage = 7.5 billion cubic meter (Bigger than Sirkit but smaller than Bhumibol)

Water surface area = 350km2 at Full Supply Level (FSL)

FSL at = EL 165 m (from Sea Level)

Average annual rainfall = 5.5 billion cubic meters

25-year maximum = 7.9 billion cubic meters per annum

Type of spillway = Non regulated gate (Free surface flow) Its bottom crest is at FSL (Bhumibol doens't have this type of gate. Therefore as you can learn later Bhumibol will work for the flood if water level yend to violate its FSL). For Sirikit, I'm not sure. If Sirkit has this type of spillway gate then the way they operated the reservoir during last year's flood was flaw.

Flood retention volume = 3billion cubic meters (From EL 165m - EL 172m)

Reservoir flood design = 7000m3/s.

Design flood return freuency = 1 in 1000 years.

* Note the design engineers of the dam were very confident that the dam does not require any sluice gate. I share that sentiment. So we can't draw down our reservoir level by other mean rather than via power generation. Maximum daily discharge is 30 million cubic meters (~1 billion cubic meters per month). Beware ! Many sluice gates you have the higher tendency for dam operators to make mistake!

Intensity of flood to be captured by the reservoir = 3billion cubic meters in 7 days (This one was determined by me, 8 years ago to optimize power generation while keeping flood risk below 2.5%)

Flood return frequency : 1 in 40 years.

Monsoon season : Nov - Mid January (Once it extended to Feb)

The strategy-

You see the underlying problem to deal with flood. The expected flood intensity is 3 billion cubic meters that might fall in 7 days. Whilst our discharge capacity is only 210 million cubic meters in 7 days. We can't race with the expected flood flow when it strikes. So we have to deal with it before. Given as short as two months period the reservoir discharge is almost always greater than accumulated rainfalls for the same period. This enables us to drawdown our reservoir water level about 8 meters below the FSL so that we have about 3 billion cubic meters of margin. We need more than 7 months every year to achieve this objective. We will ensure this margin will be made available by 1st Nov every year. We don't need weather forecast to come with this strategy. I would say statistical method is still the best for this purpose!

I think you should able to see that if 3 billion cubic meters of flood waters that fall in 7 days our reservoir can take it all even if we keep outgoing discharge at minimum says 10 million cubic meters per day. Since the flood of this intensity has return probability 2.5% therefore, for any year 97.5% chances we are going to beat the flood completely without losing a drop of water. This is the very straigh forward scenario.

How about if the reservoir has to face the biggest flood in 1600 years or two 1 in 40 year flood frequency that strike 14 days? So we will be facing 6 billion cubic meters of flood waters. What happens next? Answer: We take the 7 days and the remaining 7 days will be placed inside the flood retention storage above FSL. The non regulated spillway will ensure that 3 billion cubic meters of flood water will be discharge out naturally by gravity for longer than 3 months. Therefore the peak flood flow in 7 days will be made smaller by 4 folds as it appears at the dowstreams . Although the flood at dowstreams cannot be prevented but the reservoir + our flood control strategy will able to reduce 1 in 1600 years flood as small as 1 in 20 years flood!

Bhumibol dam does not have flood retention storge as ours. How it is going to deal with the flood with intesity greater than it can handle? If 3 billion cubic meters of flood waters try to violate its FSL the dam operators will open the sluice gates. They will keep the opening wider until the water level cease to increase. What does it mean? The dam will no longer hold any additional flood water since it has no more space to store the water. So the operators try to balance between incoming flood flow with total discharge of the dam. This will make flood at down stream even worse when compared to as if the dam is not there in the first place.....

[maidu]

ResX's note has lots of numbers and measurements. However, all the calculations of a hundred experts can't negate the fact that Bangkok is built in a flood-plain. It's a mudflat that is sinking an average of 10 cm per year in places. Seas are rising. No amount of calculations or expenditues or reservoirs or massive pumps or splillways, or monkey-cheeks, or walled rivers, are going to significantly counter the forces of mother nature. Tides will continue. Water seeks its level.

A trillion trillion baht of concrete and sub-standard re-bar and disfunctional pumps aren't going to change the force of gravity.

[ResX]

ResX's note has lots of numbers and measurements. However, all the calculations of a hundred experts can't negate the fact that Bangkok is built in a flood-plain. It's a mudflat that is sinking an average of 10 cm per year in places. Seas are rising. No amount of calculations or expenditues or reservoirs or massive pumps or splillways, or monkey-cheeks, or walled rivers, are going to significantly counter the forces of mother nature. Tides will continue. Water seeks its level.

A trillion trillion baht of concrete and sub-standard re-bar and disfunctional pumps aren't going to change the force of gravity.

Noted. But then they should try to do what best for time being until they can resolve BKK sinking problem and rising sea level. As far as " flood plain" issue is concern, flood plain cannot be defined in isolation with peak river discharge. They must come together. So we can make a natural flood plain for 1000 years to become dry if we can lower peak discharge of the river! Netherland is good example to illustrate the point. To certain extent BKK also can be a good example too to illustrate how flood plain can be made dry 95% of the times. Thanks to your 75billion cubic meters storage reservoirs. Without them BKK is a gone case as what you have seen last year.

What Thailand needs to do is to increase 95% reliability to make BKK dry to 99.5% level. This figure was reccommended by the Dutch experts too. What I'm trying to share is it can be done by improving dams operations, and obviously a little bit designs improvements for its flood control structures here and there. I don't think TBH 350billion is required to achieve this objective.

[maidu]

ResX's note has lots of numbers and measurements. However, all the calculations of a hundred experts can't negate the fact that Bangkok is built in a flood-plain. It's a mudflat that is sinking an average of 10 cm per year in places. Seas are rising. No amount of calculations or expenditues or reservoirs or massive pumps or splillways, or monkey-cheeks, or walled rivers, are going to significantly counter the forces of mother nature. Tides will continue. Water seeks its level.

A trillion trillion baht of concrete and sub-standard re-bar and disfunctional pumps aren't going to change the force of gravity.

Noted. But then they should try to do what best for time being until they can resolve BKK sinking problem and rising sea level. As far as " flood plain" issue is concern, flood plain cannot be defined in isolation with peak river discharge. They must come together. So we can make a natural flood plain for 1000 years to become dry if we can lower peak discharge of the river! Netherland is good example to illustrate the point. To certain extent BKK also can be a good example too to illustrate how flood plain can be made dry 95% of the times. Thanks to your 75billion cubic meters storage reservoirs. Without them BKK is a gone case as what you have seen last year.

What Thailand needs to do is to increase 95% reliability to make BKK dry to 99.5% level. This figure was reccommended by the Dutch experts too. What I'm trying to share is it can be done by improving dams operations, and obviously a little bit designs improvements for its flood control structures here and there. I don't think TBH 350billion is required to achieve this objective.

Let's look at this by shifting to comparing the Titanic with the Thaitanic. The Titanic was a relatively well-made iron ship. In hindsight, engineers would have recommended many technical improvements, such as thicker sides, and additional ballast chambers which would not overflow when filled - one to another, and so on. However, the Titanic was cruising in icy waters and mother nature prevailed to sink it.

Similarly, the Bangkok region has many engineers looking at why it flooded in 2011 and what improvements could be done to try and allay future wet years (btw, all years have monsoons, and 2011 was not the wettest in recent times. Similarly, ice forms in the North Atlantic each year). Mother nature does not respect man's best efforts at trying to restrict it.

ResX suggests, "they should try to do what best for time being until they can resolve BKK sinking problem."

Maidu responds: No group of geniuses nor a bazillion dollars can resolve Bkk's sinking problem. Maybe ResX meant to say, "....until they can decide what region of higher ground to move to." That would make more sense. However, Bkk's and Thailand's leaders aren't seriously looking at the option of relocating to higher ground. Instead, they will be spending tens of trillions of baht over the next 15 years, trying to keep the Thaitanic from sinking. Their childrens' or grandchildren's generation might have the intelligence to start making the move, but by then, their elders will have poured tens of trillions down the drain (and in to well-connected and unscrupulous contractors' pockets).

[ResX]

ResX's note has lots of numbers and measurements. However, all the calculations of a hundred experts can't negate the fact that Bangkok is built in a flood-plain. It's a mudflat that is sinking an average of 10 cm per year in places. Seas are rising. No amount of calculations or expenditues or reservoirs or massive pumps or splillways, or monkey-cheeks, or walled rivers, are going to significantly counter the forces of mother nature. Tides will continue. Water seeks its level.

A trillion trillion baht of concrete and sub-standard re-bar and disfunctional pumps aren't going to change the force of gravity.

Noted. But then they should try to do what best for time being until they can resolve BKK sinking problem and rising sea level. As far as " flood plain" issue is concern, flood plain cannot be defined in isolation with peak river discharge. They must come together. So we can make a natural flood plain for 1000 years to become dry if we can lower peak discharge of the river! Netherland is good example to illustrate the point. To certain extent BKK also can be a good example too to illustrate how flood plain can be made dry 95% of the times. Thanks to your 75billion cubic meters storage reservoirs. Without them BKK is a gone case as what you have seen last year.

What Thailand needs to do is to increase 95% reliability to make BKK dry to 99.5% level. This figure was reccommended by the Dutch experts too. What I'm trying to share is it can be done by improving dams operations, and obviously a little bit designs improvements for its flood control structures here and there. I don't think TBH 350billion is required to achieve this objective.

Let's look at this by shifting to comparing the Titanic with the Thaitanic. The Titanic was a relatively well-made iron ship. In hindsight, engineers would have recommended many technical improvements, such as thicker sides, and additional ballast chambers which would not overflow when filled - one to another, and so on. However, the Titanic was cruising in icy waters and mother nature prevailed to sink it.

Similarly, the Bangkok region has many engineers looking at why it flooded in 2011 and what improvements could be done to try and allay future wet years (btw, all years have monsoons, and 2011 was not the wettest in recent times. Similarly, ice forms in the North Atlantic each year). Mother nature does not respect man's best efforts at trying to restrict it.

ResX suggests, "they should try to do what best for time being until they can resolve BKK sinking problem."

Maidu responds: No group of geniuses nor a bazillion dollars can resolve Bkk's sinking problem. Maybe ResX meant to say, "....until they can decide what region of higher ground to move to." That would make more sense. However, Bkk's and Thailand's leaders aren't seriously looking at the option of relocating to higher ground. Instead, they will be spending tens of trillions of baht over the next 15 years, trying to keep the Thaitanic from sinking. Their childrens' or grandchildren's generation might have the intelligence to start making the move, but by then, their elders will have poured tens of trillions down the drain (and in to well-connected and unscrupulous contractors' pockets).

Thank you maidu. Points well understood. We are not in argument right from the start. After all we just talk about two separate issues. My issue is about how to protect BKK from floods as long as time permits. Your issue is to have the permanent solution.

Like it or not BKK will be there the way it did at least over the next 15 years. This is the reality that everybody have to accept at the moment. What I'm trying to say, even this is the case, the situation is not entirely hopeless as many people try to paint the scenario. I'm not trying to provide words of comfort. I really beleive with what I say. My belive is guide by my expertise in this area.

You said that many engineers were looking about the flood problem in 2011. Maybe you are right but I know for sure all of them failed to look at the most crucial issue, i.e. by hook or by crook all flood control dams in Thailand should have to have stroge margin at least 17 billion cubic meters by 1 st October every year. They should try to optimize this margin at least until november end. This can be done fairly easy if they develop mathematical models for the entire Chao Pharaya catchment. In 2011, it seemed to me the persons in charge in dams operations cheered when all dams levels approaching 100% storage capacity some claimed as early as August. They should by that time, or if not by now that allowing the dams to achieve 100% filled before the monsoon is over is a fatal error.

You also mentioned that 2011 flood is not the biggest so far. But then why then it was big then? Don't tell me BKK has sunk by 1m over the last 50 years! Actually, I was trying to provide the answer to your observation many times in my previous posts. I have gone through deliberate study before I can make the claim that, there was no valid Standard Operating Procedure (SOP) about dams operations that I can see over the last 8 years. The operations of the dams were so random that BKK saved from floods many times in the past because of marely good lucks. Actually, by having reservoirs with the size of 75 billion cubic meters, 95% chances is already in favor of no flood scenario. You don't need any SOP to secure this odd. But to raise the odd from 95 to 99.5% is entirely another type of game plan.

Even until today, I have no clue to suggest water management authorities in Thailand know precisely "the enemy" that they have to face. Try ask them what intensity of flood thta they are currently trying to deal with and what is its return probability. I would say you don't find the valid answers. They have to define these two things clearly before anything else. If they don't they can spend TBH 350billions but nothing is going to chance.....

I give three important tips for Thailand to face the coming floods. They are for free. That doesn't mean they are useless.

1. 17 billion cubic meters of flood waters can come over the duration of 60 days. But the flood control strategy has to be prepared as if they come in at most in two weeks.

2. It is true that 1 in 50 years flood return has Average Recurrence Frequency 20 times in 1000 years, but the strategy has to be implemented as if it comes overy year over the next 50 years.

3. If nobody cruch the numbers to come with accurate dams releases and when to release before and during flood periods using many equtaions that can be 15 times more complex than what I have illustrated, then it can be sure that they will never get the right result that they want. This simply means dams releases are not coordinated. The decisions about when to release and by how much have become the operational objectives for each dam. If this is the case, you cannot expect other scenario then chaos. This is like a country that has to leader. Remember 2011 floods?

[folium]

ResX's note has lots of numbers and measurements. However, all the calculations of a hundred experts can't negate the fact that Bangkok is built in a flood-plain. It's a mudflat that is sinking an average of 10 cm per year in places. Seas are rising. No amount of calculations or expenditues or reservoirs or massive pumps or splillways, or monkey-cheeks, or walled rivers, are going to significantly counter the forces of mother nature. Tides will continue. Water seeks its level.

A trillion trillion baht of concrete and sub-standard re-bar and disfunctional pumps aren't going to change the force of gravity.

Noted. But then they should try to do what best for time being until they can resolve BKK sinking problem and rising sea level. As far as " flood plain" issue is concern, flood plain cannot be defined in isolation with peak river discharge. They must come together. So we can make a natural flood plain for 1000 years to become dry if we can lower peak discharge of the river! Netherland is good example to illustrate the point. To certain extent BKK also can be a good example too to illustrate how flood plain can be made dry 95% of the times. Thanks to your 75billion cubic meters storage reservoirs. Without them BKK is a gone case as what you have seen last year.

What Thailand needs to do is to increase 95% reliability to make BKK dry to 99.5% level. This figure was reccommended by the Dutch experts too. What I'm trying to share is it can be done by improving dams operations, and obviously a little bit designs improvements for its flood control structures here and there. I don't think TBH 350billion is required to achieve this objective.

Let's look at this by shifting to comparing the Titanic with the Thaitanic. The Titanic was a relatively well-made iron ship. In hindsight, engineers would have recommended many technical improvements, such as thicker sides, and additional ballast chambers which would not overflow when filled - one to another, and so on. However, the Titanic was cruising in icy waters and mother nature prevailed to sink it.

Similarly, the Bangkok region has many engineers looking at why it flooded in 2011 and what improvements could be done to try and allay future wet years (btw, all years have monsoons, and 2011 was not the wettest in recent times. Similarly, ice forms in the North Atlantic each year). Mother nature does not respect man's best efforts at trying to restrict it.

ResX suggests, "they should try to do what best for time being until they can resolve BKK sinking problem."

Maidu responds: No group of geniuses nor a bazillion dollars can resolve Bkk's sinking problem. Maybe ResX meant to say, "....until they can decide what region of higher ground to move to." That would make more sense. However, Bkk's and Thailand's leaders aren't seriously looking at the option of relocating to higher ground. Instead, they will be spending tens of trillions of baht over the next 15 years, trying to keep the Thaitanic from sinking. Their childrens' or grandchildren's generation might have the intelligence to start making the move, but by then, their elders will have poured tens of trillions down the drain (and in to well-connected and unscrupulous contractors' pockets).

Thank you maidu. Points well understood. We are not in argument right from the start. After all we just talk about two separate issues. My issue is about how to protect BKK from floods as long as time permits. Your issue is to have the permanent solution.

Like it or not BKK will be there the way it did at least over the next 15 years. This is the reality that everybody have to accept at the moment. What I'm trying to say, even this is the case, the situation is not entirely hopeless as many people try to paint the scenario. I'm not trying to provide words of comfort. I really beleive with what I say. My belive is guide by my expertise in this area.

You said that many engineers were looking about the flood problem in 2011. Maybe you are right but I know for sure all of them failed to look at the most crucial issue, i.e. by hook or by crook all flood control dams in Thailand should have to have stroge margin at least 17 billion cubic meters by 1 st October every year. They should try to optimize this margin at least until november end. This can be done fairly easy if they develop mathematical models for the entire Chao Pharaya catchment. In 2011, it seemed to me the persons in charge in dams operations cheered when all dams levels approaching 100% storage capacity some claimed as early as August. They should by that time, or if not by now that allowing the dams to achieve 100% filled before the monsoon is over is a fatal error.

You also mentioned that 2011 flood is not the biggest so far. But then why then it was big then? Don't tell me BKK has sunk by 1m over the last 50 years! Actually, I was trying to provide the answer to your observation many times in my previous posts. I have gone through deliberate study before I can make the claim that, there was no valid Standard Operating Procedure (SOP) about dams operations that I can see over the last 8 years. The operations of the dams were so random that BKK saved from floods many times in the past because of marely good lucks. Actually, by having reservoirs with the size of 75 billion cubic meters, 95% chances is already in favor of no flood scenario. You don't need any SOP to secure this odd. But to raise the odd from 95 to 99.5% is entirely another type of game plan.

Even until today, I have no clue to suggest water management authorities in Thailand know precisely "the enemy" that they have to face. Try ask them what intensity of flood thta they are currently trying to deal with and what is its return probability. I would say you don't find the valid answers. They have to define these two things clearly before anything else. If they don't they can spend TBH 350billions but nothing is going to chance.....

I give three important tips for Thailand to face the coming floods. They are for free. That doesn't mean they are useless.

1. 17 billion cubic meters of flood waters can come over the duration of 60 days. But the flood control strategy has to be prepared as if they come in at most in two weeks.

2. It is true that 1 in 50 years flood return has Average Recurrence Frequency 20 times in 1000 years, but the strategy has to be implemented as if it comes overy year over the next 50 years.

3. If nobody cruch the numbers to come with accurate dams releases and when to release before and during flood periods using many equtaions that can be 15 times more complex than what I have illustrated, then it can be sure that they will never get the right result that they want. This simply means dams releases are not coordinated. The decisions about when to release and by how much have become the operational objectives for each dam. If this is the case, you cannot expect other scenario then chaos. This is like a country that has to leader. Remember 2011 floods?

ResX

You seem to be a rare breed on TV...someone who knows what he is talking about!

If that is the case, could you enlighten me as to the causes of the flooding that hit Thailand's lower Chao Phraya Basin last year at a cost of some $40billion.

Just a case of input overload, human error or a cocktail of the two?

Thanks

[ResX]

ResX

You seem to be a rare breed on TV...someone who knows what he is talking about!

If that is the case, could you enlighten me as to the causes of the flooding that hit Thailand's lower Chao Phraya Basin last year at a cost of some $40billion.

Just a case of input overload, human error or a cocktail of the two?

Thanks

To summarize, two things that contributed to the floods: (1) The authorities were indecisive about the intensity of floods they wished to deal with.... How did they know everything work according to the plan if didn't even know what to expect? (2) They didn't really clear about when to declare that they have won against the floods... Last year they celebrated their "appear to be a success" two months before the game was over. Some say most of the dams had 100% filled as early as August. They had two months to go through the monsoon! This is like armies going to war without enough fire powers. You can expect they can win the war if only their enemy retreats due to some reasons.

[welbymd]

Old man river will leave it's banks when it wants to. Any work to help prevent flooding should begin downstream and work its way upstream. I just can't figure out how they're going to do it, and in the time frame they say. Hopeful thinking?

Corrogated, interlocking panels are the cheapest, quickest and most unobtrusive devices, but they still stick up and look unslightly. Building dikes, there will be outrage over lost homes and businesses. How often does this type flooding happen, about every 15 years? I hope whatever plan they implement can be finished in the next 20 years.

[473geo]

in the meantime, NIKON fired off an official announcement declaring they lost more than 130 million $ because of the flooding in their factory in Ayutthaya !

Extraordinary Losses Due to the Flooding in Thailand

http://www.nikon.com...012/0203_01.htm

... i guess now they will think twice before investing in thailand again.

"Nikon also expects that the losses relating to the fixed assets and inventories will be compensated by additional insurance payment which is currently pending."

[cloudhopper]

"Nikon also expects that the losses relating to the fixed assets and inventories will be compensated by additional insurance payment which is currently pending."

And will never be offered again.

[Reasonableman]

How do you get insurance in future if your factory lies in a flood drainage pathway?

"Nikon also expects that the losses relating to the fixed assets and inventories will be compensated by additional insurance payment which is currently pending."

And will never be offered again.

[473geo]

Good I might buy a few Nikon shares, they will save the upgraded cost of the premium this year.....

Edited February 19, 2012 by 473geo

[Reasonableman]

Nikon makes a great range of underwater cameras, so that's probably a good strategic move. Good luck.

Good I might buy a few Nikon shares, they will save the upgraded cost of the premium this year.....