ResX

It is a matter of time that they have to accept that dams have to be a part of us. It will not take longer 30 years from now. How many floods like last year's flood that Thailand is prepared to face in near future?

HAII is (relatively) independent of the government and runs its own network of telemetry stations around the country. They are very much on top of the technology as well as the scientific principles of modeling.

Flood modeling on a national basis is an extremely complex objective and of course will never be totally accurate. (The nature of a model is that it serves as an abstraction of reality.) However, there's no reason to bash this attempt. Integrating multiple domains usually makes models more accurate (at the cost of increasing their complexity).

As for spending money on eliminating the "root causes" of flooding, this is of course important, but the growing number of extreme weather events means that prevention is always going to be behind the curve. If this model proves to be accurate, it can contribute significantly to the country's flooding problems by providing at least short term quantitative predictions.

Well I will except what you say as being fact,

What I don't understand is how a 7 day warning is going to help munch if 358 days of working to avoid the problem don't help munch.

Yes I know 7 days will give the people time to move out of their homes and hopefully save what is in them. But the damage to the homes will still be there. And if handled like the last flood many of them will not have a job to go to.

You can see the real problem right? As I mentioned above, such model cannot be used just like that. The way that it can be used to add value is to provide the likelyhood for peak flood flows over the next one week so that the releases from all dams can be averaged out over a longer duration, By doing so the peak flood flow can be trimmed down. . For example, without the model we maybe forced to release 7 billion cubic meter of waters from all dams only when they come. With the model, that can predict 7 days ahead we may want to discharge 7 billion cubic meter in 14 days. This will cut down the peak discharge by 50% and it can be made with minimum negative implications.

Okay. Now the model predicts Bhumibol and Sirkit dam will be getting 7billion cubic meter of flood waters over 7 days duration beginning from next Monday. What the dams operators can do? Please do not release 7billion cubic meter of waters in 7 days prior to the coming Monday. Otherwise at best they just make the flood to come even earlier. At worst, the model has predicted wrongly but the flood has occurred by mistake.

Don't get me wrong. The model is useful as long as the strategy to use it is correct. But don't over estimate its capability.

In my family I have one retired and one still active engineers of the Bhumipon Dam.

"No one listens to us, no one follows the instructions of our venerated KING Bhumiphon. This is Thailand."

Thank you. I know that. "Politicians like to get hold the problem they understand rather than the solution they don't as long as they get votes".

Okay. Now the model predicts Bhumibol and Sirkit dam will be getting 7billion cubic meter of flood waters over 7 days duration beginning from next Monday. What the dams operators can do? Please do not release 7billion cubic meter of waters in 7 days prior to the coming Monday. Otherwise at best they just make the flood to come even earlier. At worst, the model has predicted wrongly but the flood has occurred by mistake.

Don't get me wrong. The model is useful as long as the strategy to use it is correct. But don't over estimate its capability.

You are making a progress. But then please understand that such model is worth third rank defence as far as flood control is concern. Without having first and second line of defence this third rank defence can cause more harm than good. The model is more useful for power generation than flood control since it can be used to optimize power output of the generating units.

Back here in my country we can do away with such model. So far our record to curb extreme floods for major flood control dams are better than Thailand. I'm not saying ithe model is useless but don't rely too much on it (for flood mitigation & control) just because such model is very advanced thing.

Dam management 2012

Last year Bhumipol and Sirikit dams became full by the end of September, and the resulting large uncontrolled spillovers added to the flood peak creating havoc in Nakhon Sawan and many other areas along the Chao Phraya river. This calls for improved dam management in the coming 2012 rainy season and forward, and RID/Egat has thankfully already taken the first step by lowering the reservoir water volumes to 57-58 % of the reservoir capacities before this rainy season. So far so good.

The next important step is to ensure that the reservoir water volumes from now until August 1 stay low, that is around the present level (by releasing the incoming flows in an appropriate manner). The volume on August 1 should not exceed 8000 MCM (60 %) in Bhumipol reservoir and 5,500 MCM (57 %) in Sirikit reservoir. This will ensure an available flood control volume of 5500+4000=9500 MCM on August 1, which is appropriate to reduce the risk of excessive dam spillover, even in case of high rainfalls in August-October like last year. In case of a dry year the presently available water volumes are sufficient to sustain basic irrigation and hydropower requirements troughout the year.

Last year the available flood control volume on May 1 was 7300+4700=12000 MCM, but on August 1 only 5000+1700=6700 MCM. The mistakes made last year, by allowing the reservoir water levels increase fast during the 3-month period May-July, should not be repeated.

Good

Dam management 2012

Last year Bhumipol and Sirikit dams became full by the end of September, and the resulting large uncontrolled spillovers added to the flood peak creating havoc in Nakhon Sawan and many other areas along the Chao Phraya river. This calls for improved dam management in the coming 2012 rainy season and forward, and RID/Egat has thankfully already taken the first step by lowering the reservoir water volumes to 57-58 % of the reservoir capacities before this rainy season. So far so good.

The next important step is to ensure that the reservoir water volumes from now until August 1 stay low, that is around the present level (by releasing the incoming flows in an appropriate manner). The volume on August 1 should not exceed 8000 MCM (60 %) in Bhumipol reservoir and 5,500 MCM (57 %) in Sirikit reservoir. This will ensure an available flood control volume of 5500+4000=9500 MCM on August 1, which is appropriate to reduce the risk of excessive dam spillover, even in case of high rainfalls in August-October like last year. In case of a dry year the presently available water volumes are sufficient to sustain basic irrigation and hydropower requirements troughout the year.

Last year the available flood control volume on May 1 was 7300+4700=12000 MCM, but on August 1 only 5000+1700=6700 MCM. The mistakes made last year, by allowing the reservoir water levels increase fast during the 3-month period May-July, should not be repeated.

Good work steenasger. I think you have something to do with dams operations in Thailand. Your plan is pretty good. It can reduce flood risk and size significantly.

Let me share my opinion to further improve dams operations in Thailand. There are two more things that the authorities in Thailand has to look critically. Firstly, when the flood cannot be avoided then they have to know how to cut down its peak flow- This part with due respect, I think was missing during the last year's flood control operationn. Nobody can be sure he can always beat the future flood. What he has to know for sure is about how to minimize the peak flood flow.

Secondly, please look critically about the existing designs for flood control stuctures in particular for Bhumibol and Sirkit dams. These two dams are the most critical dams in Thailands for water management. As far as I know the dams were designed way back to the 50's. They may be able to serve the purpose for the 50's. But today, things have changed a lot.

Bhumibol and Sirkit dams shall not be exposed to a scenario that they have to make decisions under "duress".

but there are of course other issues to be considered as well, such as coordination of the releases from the two dams, etc.

That was what I meant regarding to reduce peak flood flow at times things are not going the way you expect. You can achieve it by coordinate the dams releases. Not limited to those two dams in the north. The dams at the downstreams have to be considered as well. The basic idea is "to hold" the waters that can be held and to "release" the waters that cannot be held. This is the reason why I pointed out to the designed of flood control structures especially for the Bhumibol & Sirkit dam.

I think you should know by now that Bhumibol and Sirkit dams are the "Key Success Factor" for flood control operation for the entire Chao Pharaya. If these two dams sucessfully can hold flood waters at least until Nov end then there could be flood or no flood at the dowstream. That depends on the intensity of loacalized rainfalls. Whatever might be the case you will not see the floods as big as near the size of the one that struck last year. But then if these two dams fail to hold flood waters during the critical period, then the dowstream will become unprotected at all. In this case the last year's flood might not be the biggest that you will see over the next 50 years.

Dam management 2012

Last year Bhumipol and Sirikit dams became full by the end of September, and the resulting large uncontrolled spillovers added to the flood peak creating havoc in Nakhon Sawan and many other areas along the Chao Phraya river. This calls for improved dam management in the coming 2012 rainy season and forward, and RID/Egat has thankfully already taken the first step by lowering the reservoir water volumes to 57-58 % of the reservoir capacities before this rainy season. So far so good.

The next important step is to ensure that the reservoir water volumes from now until August 1 stay low, that is around the present level (by releasing the incoming flows in an appropriate manner). The volume on August 1 should not exceed 8000 MCM (60 %) in Bhumipol reservoir and 5,500 MCM (57 %) in Sirikit reservoir. This will ensure an available flood control volume of 5500+4000=9500 MCM on August 1, which is appropriate to reduce the risk of excessive dam spillover, even in case of high rainfalls in August-October like last year. In case of a dry year the presently available water volumes are sufficient to sustain basic irrigation and hydropower requirements troughout the year.

Last year the available flood control volume on May 1 was 7300+4700=12000 MCM, but on August 1 only 5000+1700=6700 MCM. The mistakes made last year, by allowing the reservoir water levels increase fast during the 3-month period May-July, should not be repeated.

Good

Dam management 2012

Last year Bhumipol and Sirikit dams became full by the end of September, and the resulting large uncontrolled spillovers added to the flood peak creating havoc in Nakhon Sawan and many other areas along the Chao Phraya river. This calls for improved dam management in the coming 2012 rainy season and forward, and RID/Egat has thankfully already taken the first step by lowering the reservoir water volumes to 57-58 % of the reservoir capacities before this rainy season. So far so good.

The next important step is to ensure that the reservoir water volumes from now until August 1 stay low, that is around the present level (by releasing the incoming flows in an appropriate manner). The volume on August 1 should not exceed 8000 MCM (60 %) in Bhumipol reservoir and 5,500 MCM (57 %) in Sirikit reservoir. This will ensure an available flood control volume of 5500+4000=9500 MCM on August 1, which is appropriate to reduce the risk of excessive dam spillover, even in case of high rainfalls in August-October like last year. In case of a dry year the presently available water volumes are sufficient to sustain basic irrigation and hydropower requirements troughout the year.

Last year the available flood control volume on May 1 was 7300+4700=12000 MCM, but on August 1 only 5000+1700=6700 MCM. The mistakes made last year, by allowing the reservoir water levels increase fast during the 3-month period May-July, should not be repeated.

Good work steenasger. I think you have something to do with dams operations in Thailand. Your plan is pretty good. It can reduce flood risk and size significantly.

Let me share my opinion to further improve dams operations in Thailand. There are two more things that the authorities in Thailand has to look critically. Firstly, when the flood cannot be avoided then they have to know how to cut down its peak flow- This part with due respect, I think was missing during the last year's flood control operationn. Nobody can be sure he can always beat the future flood. What he has to know for sure is about how to minimize the peak flood flow.

Secondly, please look critically about the existing designs for flood control stuctures in particular for Bhumibol and Sirkit dams. These two dams are the most critical dams in Thailands for water management. As far as I know the dams were designed way back to the 50's. They may be able to serve the purpose for the 50's. But today, things have changed a lot.

Bhumibol and Sirkit dams shall not be exposed to a scenario that they have to make decisions under "duress".

I will make a wild guess and say right now there will not be flooding in 20 provinces this year. Already the conditions that helped to create the floods last year are not the same.

2011 almost continuous rain from 1st March, ground became saturated and by August nowhere for water to run off, a few large typhoon leftovers hit northern Thailand in quick succession rivers overflowed and combined with water drainage/release mismanagement we got the floods.

Simply my observations and I am often wrong!

Every General fights a new war using the tactics of the last war.

We all agree that last years rainfall was extraordinary, and anyone saying that nothing is being done to prepare for a repeat this year is wrong.

That's not where the problem lies, the problem lies with the lack of long term water management. The memories of last year will fade, the dredging will slow down over the next few years, the canals will be built over again, then when the next flood comes it will be back to square one.

I hope I'm wrong........I don't think I'm wrong though.

It may or may not be flood this year. What had happenned in Mac this year has little bearing on Sept to Oct floods this year. The critical period for Chao Phraya catchment is end of Sept to mid of Nov. This duration that counts. If most of flood control dams do not have at least 15% empty by end of September then I will say you have at least 25% chances that there are going to be flooding somewhere. The floods might not be as big as the last year's event but flood is still flood.

If most of the dams will be fully filled by end of September then I wll say 98% changes you are going to see another flood this year. The size is more or less equal to the last year's flood if not bigger than that.

Let me make it simple. Flood waters during the last year's floods were not originated from Mac to August rainfalls. They came from Sept to November.

Beware of the end of September. Last year, most of the dams in Thailand were beaten by as early as by the1st September. Thailand marched through the monsoon "naked". People like us who know the behaviour of flood flow could easily see that Thailand was beaten by floods at least a month earlier than it supposed to be. Flood or no flood this conclusion holds.

http://www.kromchol.com/array/BDam.htm check the water levels, the Bhumibol and Sirikit dams are still above the norm for this time of the year at 56 and 58% respectively

Your water experts have to look at both ways, namely extreme flood or extreme drought event. All the major dams have to be strategized so that they can serve all their intended purposes under both extremes.

Severe flood last year, as far as I can see has turned the dams in Thailand to be used mainly for flood control. I'm sure this is not the only intended purpose of the dams in the first place.

When somebody decided to bring the dam water levels down to 40% (or 60% depends on how ypou define 100%) hydro power plants owner would have been the most happy authority. Most of the stored waters that been collected during the last year's floods have been given to the hydro turbines.

I have proposed many times in the past that Sirkit and Bhumibol, at best have to be brought diown in such a manner they can arrest at least 7 billion cubic meters. 4 billion cubic mters for Bhumibol and 3 billion cubic meters for Sirkit. Anything above that is okay as long as you don't mind to give up the other two important functions of the dams, namely irrigation and domestic water supply.

It doesn't seem that you don't mind. Therefore, I will suggest your water management experts have to go back to the drawing board.

flood control requirement.

Bhumibol and Sirkit dams are expected to deal with annual average rainfall of 19billion ubic meters. Once in 50 years you can expect the dams have to deal with at most 7 billion cubic meters of flood waters that flow in 7-14 days. Based on effective storage volumes for Bhumibol and Sirkit dams 10 and 8 billion cubic meters respectively, the optimum storage levels for these two dams before the monsoon are at 60% level. Anything lower than this level, I think the authororities have not done justice to irrigation and domestic water supply. If it is okay with farmers and other stake holders, then I have nothing to complaint.

There is a possibility that these two dams need to hold higher than 7 billion cubic meters of water. If this is the case then new dam has to be built upstream or dowstream to either one of these dams. There is no short cut to ensure these two dams can provide their intended purposes namely, flood control, irrigation and domestic water supply. Don't even think there is any possible short cut.

I will make a wild guess and say right now there will not be flooding in 20 provinces this year. Already the conditions that helped to create the floods last year are not the same.

2011 almost continuous rain from 1st March, ground became saturated and by August nowhere for water to run off, a few large typhoon leftovers hit northern Thailand in quick succession rivers overflowed and combined with water drainage/release mismanagement we got the floods.

I am not saying there won't be some flooding but nowhere near what we had last year.

Simply my observations and I am often wrong!

That is what many people beleive. For laymen on the street it it doesn't really matter what they want to beleive. But for flood control authorities such beleive will bring another trouble.

If you can recall 2011, autorities in Thailand beleived that it was going to be a drought. Thta was not the first time they predicted an event that thta sholud not predict in the first.

What I'm proposing is just assume the same flood llike last year will come this year. Be prepare as if it going to happen. That is how the flood mitigation shall be dealt with....

Exellent observation and proposal....that is how to do it!

Thank you mate for your sincere compliment. I'm about to leave Chiang Mai.

Every General fights a new war using the tactics of the last war.

We all agree that last years rainfall was extraordinary, and anyone saying that nothing is being done to prepare for a repeat this year is wrong.

That's not where the problem lies, the problem lies with the lack of long term water management. The memories of last year will fade, the dredging will slow down over the next few years, the canals will be built over again, then when the next flood comes it will be back to square one.

I hope I'm wrong........I don't think I'm wrong though.

"The memories of last year will fade, the dredging will slow down over the next few years, the canals will be built over again, then when the next flood comes it will be back to square one"

Good point. That was one of the issued that has been raised during the submit. It is true that to sustain the desire to combat this extreme event is one of the things that is lacking. I mean not only true for Thailand. As the submit has taught me, US, Australia, New Zealand, Pakistan, my country are not spared from the same problem.

The delegates will try to adress this problem. Lesson learned from Thailand flood, the submit will put more emphasize on flood mitigation and control in the future undertaking.

One more thing I wish to share based on one of the resolutions of the submit. Most extreme flood events that occured iover the past had little thing to do with climate change. This included floods in Thailand....

I will make a wild guess and say right now there will not be flooding in 20 provinces this year. Already the conditions that helped to create the floods last year are not the same.

2011 almost continuous rain from 1st March, ground became saturated and by August nowhere for water to run off, a few large typhoon leftovers hit northern Thailand in quick succession rivers overflowed and combined with water drainage/release mismanagement we got the floods.

I am not saying there won't be some flooding but nowhere near what we had last year.

Simply my observations and I am often wrong!

That is what many people beleive. For laymen on the street it it doesn't really matter what they want to beleive. But for flood control authorities such beleive will bring another trouble.

If you can recall 2011, autorities in Thailand beleived that it was going to be a drought. Thta was not the first time they predicted an event that thta sholud not predict in the first.

What I'm proposing is just assume the same flood llike last year will come this year. Be prepare as if it going to happen. That is how the flood mitigation shall be dealt with....

I was attending the submit too. I was there listening to his keynote speech. I'm still here in Chiang Mai at the moment.

I did mentioned in one of my posts that I have been to Sirkt and Bhumibol dam about 9-10 years ago. During the submit I met the person who accompanied my visit to Bhumibol and Sirkit. I was quite suprised that could still remember me.

Reading the link and trying to understand the units, did not help a great deal. However, it was very useful.

It appears the Chao Phraya system drains 35% of the land area of Thailand.

From the wikipedia it appears the Bhumidol and Sirikit dams control 22% of the runoff. This is not a great situation, in an emergency.

Quote '' The Bhumibol and Sirkit Dams control 22% of the Chao Phraya's annual runoff combined.[3.

End Quote.

Obviously there has been a serious mismatch for many years.

Therefore, the doubling of storage on the Chao Phraya, as mentioned by the OP, is a large step, in the right direction ---- but not a final solution --- more a temporary solution.

Going through the link you wil find a figure that states 85km3. This is actually equal to 85 billion cubic meter or 85 X 1000 X 1000 X 1000 m3

Based on taverage annual inflow of 75 billion cubic meter for the CP river, it is more than sufficient to keep flood risk around 2% if the dams in the north can hold at least 7 billion cubic meter for at least two weeks. The dams (in the north) shall able to hold the flood water and they shall not be allowed to be under "force to release scenario", i.e. they have to open their sluice gates. It is reasonably acceptable if the dams have to discharge through their natural overflow spillways, if they have ones. Care shall be taken to prevent opening of sluice gates. there must be a clear strategy from the start to prevent opening the sluices gates unless for the very extreme flood flow (return frequency lower than 1-in-50).

Once the downstream is "starved" by 7 billion cubic meter of water by the dams in the north during 1-in-50 year flood return, it is unlikely the entire flood waters within the CP catchment can cause much damage. The total active flood volume has reduced to 10 billion cubic meter. The entire CP river alone can store natural flood, based on my estimate, is 1-1.5 billion cubic meter. There are many smaller dams along the CP river. They have to be used effectively to deal with the remaining 8-9 billion cubic meter.

There are two critical success fartors to deal with floods in Thailand: 1) How effective dams in the north to serve as pilot dams to control the entire flow dowstream 2) If the dams in the north are going to fail to keep flood waters, sluice gates opening has to be well coordinated -Right time and right sequence relative to the down stream dams

In the other paper, Plodprasop claims there is only a 1% chance of a flood occuring next year. So, why are they spending even one baht?

Honestly, where do they find these muppets?

As far as I can see it is not smaller than 2%. Even he is right the chance comes with conditions. For example, if dam operators allow their dams to be fully filled by as ear;ly as Sept this year, then the chance to have floods in October will become very close to 95%. The only thing I can't tell you is the size of the expected flood.

The bad news is given 100 years period it is 100% chance that a 1% flood event will strike at least once. I can assure you that the statement is 100% valid. But then when is such event will strike? This is subject to the speculation. Any year over the next 100 years is possible. That includes this year. . .

Why do these people always come to Thailand? Why don't they go somewhere else?

Can we be sure about it?

An interesting interview indeed, both for what was said, implied, and left unsaid.

The 10 billion cbm stored by the dams, equates to 1 month full flow of the Chao Praya river (at 4000 cbm per second).

The 4.6 million rai at 2 meter depth average is 14 billion, or about another month of Chao Praya. In others words a glaring admission, that the dams are not nearly big enough.

Here is the calculation. Bhumibol & Sirkit are good for up 7billion cubic meter without compromising their roles to genarate power and to provide waters to farmers. Chao Phara dam another one billion cubic meters. Thailand needs another 7 billion to deal with one-in -fifthy years flood. There are many other dams besides these three since all dams in Thaland have storage capacity 75billion cubic meter.

I don't see any problem for 75billion cubic meter dams to deal with 17billion, 7-14 days flood flow. Unless that 75billion cubic meter dams do not belong to the CP river.The more realistic problem, as far as the information that I have is, most of the dams are in series. Your water management experts don't seem to have any clue about what does this mean. In reality such dams arrangement requires very complex coordination to execute water releases when it comes to flood. Very..very complex. Simplification is allowed if there is no problem to get BKK 2m below the flood level again.

Thank you for your detailed response, most of which I can accept as reasonable.

Could you please give info on where your figure of 75 billion total storage originates. Also you mention dams in series. Do you have a breakdown for primary dams and secondary (downstream) dams. My information (from internet) is that Thailand stores 40 billion cbm annually in the primary dams. IMHO this is not nearly enough. 80 billion would be much safer.

Your statement that management of dams in series is very complex is correct. However, in this day and age these problems have been overcome in many countries. The time constants between dams are known, and software is available too deal with the maths.

Finally your figure for Bangkok being 2 m below flood level is interesting. My understanding is that Bangkok is presently 1.2 m above sea level. I don't wish to have a major discussion about decimal points of 1 m, as this is all very close to the edge. --- so close in fact, that my toes are feeling wet.

It mentioned here 85 billion cubic meter, if my maths was correct. As I mentioned I didn't know what percentage belongs to the CP. Most likely not as high as I thought.

http://www.fao.org/nr/water/espim/country/thailand/index.stm

If I painted the river system for the CP correctly, Bhumibol and Sirkit are in parallel. But they are discharging to the mainstream of CP. That ultimately makes them in series too. Most of the downstream reservoirs such as Pasak Jalasid will end up discharging to the main stream of the CP too. Chao Pharaya dam is another one to be included. Therefore, series configuration is more accurate to describe their arrangement. These four reservoirs alone have the total live storage capacity of 20 billion ++ cubic meter.

Finally, can BKK tp be submerged 2m below flood water level? I think it is possible if the level of flood water mismanagement is around 17-20 billion cubic meter. Last year it was just around 10 billion cubic meter.

An interesting interview indeed, both for what was said, implied, and left unsaid.

The 10 billion cbm stored by the dams, equates to 1 month full flow of the Chao Praya river (at 4000 cbm per second).

The 4.6 million rai at 2 meter depth average is 14 billion, or about another month of Chao Praya. In others words a glaring admission, that the dams are not nearly big enough.

Here is the calculation. Bhumibol & Sirkit are good for up 7billion cubic meter without compromising their roles to genarate power and to provide waters to farmers. Chao Phara dam another one billion cubic meters. Thailand needs another 7 billion to deal with one-in -fifthy years flood. There are many other dams besides these three since all dams in Thaland have storage capacity 75billion cubic meter.

I don't see any problem for 75billion cubic meter dams to deal with 17billion, 7-14 days flood flow. Unless that 75billion cubic meter dams do not belong to the CP river.The more realistic problem, as far as the information that I have is, most of the dams are in series. Your water management experts don't seem to have any clue about what does this mean. In reality such dams arrangement requires very complex coordination to execute water releases when it comes to flood. Very..very complex. Simplification is allowed if there is no problem to get BKK 2m below the flood level again.

Danm cannot prevent flood, it can only delay it.

Only Buddha can prevent flood.

More accurate is dam cannot prevent flood. It can only trim it to make it smaller, as long as the sluice gates can be kept closed. Otherwise dam is going to make flood even worse.

Base on time left, the only one thing Thailand can rely on but can still produce a good result to develop a clear strategy to prevent opening of sluice gates during the peak flood flow. If they are required to be opened then do it before the flood reaches its peak or after it hits the peak.

This is like playing chess. Sluice gates are the King. Once they are opened most likely it is going to be a "Checkmate".

When talking about hydro power, I tend to agree in principle. However, in practice, once these Hydro authrities are created, they have a tendency, like all organisations, to try to perpetuate their own existence, by seeking to dammevery potentially dammable (sic) watercourse. Take a look at the history of the Hydro in Tasmania, for example. World Heritage areas inundated and destroyed to satisfy the energy demands of foreign industry, not for the needs of the population. Hydro developments need strong and enforced EIA requirements, otherwise the Hydro authority can and probably will, run amok, to the great detriment of the environment. As for the argument about fish species, it is only one of many concerns, but still a valid one.

Tas Hydro exports electricity to Vic, but they are not EXACTLY foreign. If you were referring to foreign-owned industry, at the least they pay for the power and worker's wages.

There has to be a balance between rain forest (which Tas has in abundance, and which relatively few people will ever enjoy) and cheap power and cash to build infrastructure enjoyed by nearly all. The move to demolish one dam was dropped when it was proved that the platypus population had actually increased due to more stable river flows, and the increase in nesting sites around the dam banks.

I can just imagine the outcry if they decided to put a few thousand wind turbines down there - it's an ideal location.

Wind turbines or even solar panels will make them even poorer. Surely.

Coal power plants, I think the most polluted one. We have many right here. Have to bear with them at the moment.

If we think that they have many options that is actually shaped our opinion for opposing a hydro power project. In reality, not many choices available on the table. Take the the best one. Mitigate the consequences and minimize the impact.

We can't get something out of nothing. About building up dams we have to balance between getting cheap electricity and environmental conservation. We have to be given full power to decide. That simply means the decisions to build or not to build up dams.

I think blocking the idea to build up dam due to one or two particular reasons is not just if we don't evaluate overall benefits to the population at large.

Yes, I do agree with the principal that each dam has to be built by considering all positives & negatives consequences. If overall evaluation shows overwhelming positives then why not build up one? After all not everybody can appreciate rainforest. But most likely everybody appreciate cheap electricity since it can improve standard of living.

It sounds like they want to keep the Japanese from abandoning their plants. It costs the country more to lose the Japanese plants and lose tourists than what cheap hydroelectricity is worth. Should they actually follow this plan, maybe they can actually use the dams for flood prevention, which should have always been the priority.

Power generation & flood control dam can get along nice and easy. A flood control dam as far as possible will be designed multi-purpose. The only thing that does not add up is "greed". Greed can alter the way dams are operated. If operations of dams is not regulated eventually flood control will be the first to be compromised. Remember last year's floods in Thailand?

I think they are confusing themselves. Most likely nothing has changed. They just started to learn water management & dams from the very basic.

Capacity of a dam can be defined by means of two ways. First one is by using its total storage capacity. The second one is by using its useful/effective/live storage capacity. Let us work one example using.

Bhumibol total storage capacity is 13.5billon cubic meter. Useful storage is 9.7billion cubic meter. Subtract the later from the former you will get the death storage.

If we keep Bhumibol at 45% level based on its total storage then we get target storage level of (0.45 )X 13.5= 6.1billion cubic meter. If we use 62% level based on useful storage then the we get target storage level of (0.62 X 9.7) = 6.0 billion cubic meter. They are most likely the same thing.

Or maybe they are not. I'm not sure. But 60% level is very close to the figure that I have proposed for Thailand. The exception that I know at the moment is Bhumibol dam, It has to be brought close to 50% of its useful storage. About 5 billion cubic meter mark will do. It provides storage capacity by 4.7 billion cubic meter. At this level Bhumibol dam can easily beat the biggest flood in 50 years for its own catchment. Obviously other dams have to play their roles too.

The real challenge is about where they want to keep the level. As you can see what happened last year. It depends on how accurate they anticipate and coordinate excessive flood flows when dams water level starts to increase. Thailand should worry more about this one.

If I can recall conversion factor correctly 2million Rai is equal to 3200km2 of land. If this is required for temporary measure only then I have nothing to say. But if they want to make the area permanent, something is terribly wrong. I don't know what is it. But it isn't about the flood control.

You don't need 3.2billion m2 of land to deal with 17billion cubic meter of waters. Even if Thailand has decided to take 34billion m3 of flood water that area is pretty to big. Bhumibol dam required 0nly 0.3billion m2 of land to keep at least 7billion m3 of water to stay calm.

Is my conversion factor correct? Or did I miss something?

How deep is Bhumibol Dam? And how deep do they expect the water to be over the 2 million rai?

If Bhumibol dam is 10 metres deep, you would need 3 billion m2 of land to store that water 1 metre deep.

... I think.

Roughly about 25-30m useful storage. I don't think they prepare to keep 17 billion cubic meter there. Bhumibol & Sirkit can hold at least 7 billion cubic meter. Chao Pharaya dam another close to 1 billion cubic meter, There are 197 ++ other dams scattered around in Thailand.

Maybe they need extra. At most 6.4 billion cubic meter more . In this case the height of the water will be 2m. The question is why not solve the problem like anybody else? Get an area or a few areas with total area of 300km2. Then flood the area by 20m. They get the same 6billion cubic meter storage + total area 10 folds smaller.