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Dams In North Cut Water Discharge: Thailand


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Posted

Dams in North Cut Water Discharge

The Sirikit and Bhumibol dams have been adjusting the amount of water they are discharging.

Both dams have been releasing 45 million cubic meters per day, which will improve the situation in the central region and areas around Bangkok.

Sirikit Dam Director Tanarat Bhummimakasikorn said the Sirikit Dam has been discharging between 18 million cubic meters and 15 million cubic meters of water a day because there has been rainfall to the north of the dam.

The dam was at 99 percent capacity.

In the meantime, at the Bhumibol Dam, officials have agreed to release only 30 million cubic meters each day.

Tanarat affirmed that the Sirikit Dam's structure is sound, saying that officials have been monitoring the dam around the clock.

In Tak Province, many local residents' homes, located around the dam, have been submerged under water for more than a month.

The affected locals are likely to take action to pressure dam officials to discharge more water.

Tak governor, Samart Loifa and related officials visited the five communities that have sustained the the greatest impact from the discharged water at Baan Na Subdistrict in Sam-ngao District to create an understanding among local residents about the reasons why they have to hold back the water.

The governor promised to immediately provide relief funds to assist the affected locals.

The villagers have agreed not to take any further action, saying they are satisfied.

Samart went on to say that many local residents do not understand the water discharge system as in the past, they were only minimally impacted by floods.

Unfortunately, the residents have been suffering under deep floodwater for more than a month now.

The Bhumibol Dam can accept 80 million cubic meters of water and water discharge averages 30 million cubic meters each day.

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-- Tan Network 2011-11-09

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Posted

Passak dam is down about 70 cm from the highest level a few weeks ago. So they are obviously letting out more water than they are receiving.

That is an awful lot of water they could have held back.

Posted

Yea you will be compensated... 5k baht :bah:

I can understand them wanting more water discharged from the dams. Sorry we are flooding you to save the rest of the country. But you wont get more then others in compensation. At least give people like this more for they endure more hardship for the sake of others.

Posted (edited)

Passak dam is down about 70 cm from the highest level a few weeks ago. So they are obviously letting out more water than they are receiving.

That is an awful lot of water they could have held back.

To be fair it was rather full:

- Bhumibol Dam: it reached 99 Percent of retention capacity.

- Sirikit Dam: it reached 99 Percent of retention capacity.

- Kwae Noi Dam: it reached 100 Percent of retention capacity.

- Pasak Dam: it reached 136 Percent of retention capacity.

- Ubonrat Dam (Khon Kaen Province): it reaches 120 Percent of retention capacity.

- Lampao Dam (Kalasin Province): it reaches 100 Percent of retention capacity

http://theenergycollective.com/solanalarsen/67393/thailand-flood-maps-and-disaster-monitoring-tools

I would assume there was a risk keeping it at 136% for a longer period of time.

Edited by Orac
Posted (edited)

The Bhumibol and Sirikit dams have been releasing 45m m3 a day, with Sirikit 15 - 18 and Bhumibol now down to 30. I assume that means the Sirikit dam doesn't change it's release rate? Might make sense as Sirikit is an embankment dam whereas Bhumibol a concrete arch dam.

With still billions of m3 water in front of Bangkok and around it, a drop in release from 45 to 30m m3 per day doesn't sound like an awfull lot, neither as significant :ermm:

(I know the figures somehow don't seem to add up, blame to OP)

Edited by rubl
Posted

Yea you will be compensated... 5k baht :bah:

I can understand them wanting more water discharged from the dams. Sorry we are flooding you to save the rest of the country. But you wont get more then others in compensation. At least give people like this more for they endure more hardship for the sake of others.

quote: "In Tak Province, many local residents' homes, located around the dam, have been submerged under water for more than a month.

The affected locals are likely to take action to pressure dam officials to discharge more water." unquote

<<<<<<<<<<>>>>>>>>>>>

If they are living upstream of the dam and are being flooded by the reservoir waters they are obviously living within the reservoir area designated as "FSL", (full storage level) and shouldn't be there. All dam reservoirs have a Maximum Storage Level which is a NO construction zone and there are normally building restrictions within a certain distance from the MSL shoreline. If they are living downstream of the dam discharging more water will only aggravate their plight.

Posted

what's curious: where from so much water coming into those dams?

(does China releases more water from its own dams than usually?)

I was wondering the same thing. Was the amount of rainfall just too much in too short a time?, other places north of Thailand were getting excessive rainfall also so did they then have to release more water from their dams?.

Any ideas?

Posted

If the dam is at 99%, then why houses are under the water,unless they were build illegally in the water shed area then I no one should careif they are under the water

Posted (edited)

It is highly unlikely that anyone illegally built on land near the dam, don't you think?!!

Edited by Credo
Posted (edited)

If the dam is at 99%, then why houses are under the water,unless they were build illegally in the water shed area then I no one should careif they are under the water

Terminology: Watershed area is all the surrounding country side from which the water drains from the land into the rivers, streams, brooks, which then feed into the reservoir - i.e. "The region draining into a river, river system, or other body of water." This can be many thousands of square km. The term you should use is the Maximum Storage Level area of the reservoir - see my previous post #8 above.

Edited by Prairieboy
Posted

what's curious: where from so much water coming into those dams?

(does China releases more water from its own dams than usually?)

I was wondering the same thing. Was the amount of rainfall just too much in too short a time?, other places north of Thailand were getting excessive rainfall also so did they then have to release more water from their dams?.

Any ideas?

No water came from China. Their water flows into the Mae Kong. All the water into the Bhumiphul Reservoir and the Sirikit Dam is domestic rainfall.
Posted

other places north of Thailand were getting excessive rainfall also so did they then have to release more water from their dams?

got message from a friend in Nan about heavy downpour there today and wondering whether all this water will add up to that already surrounding Bkk

Posted (edited)

Yea you will be compensated... 5k baht :bah:

I can understand them wanting more water discharged from the dams. Sorry we are flooding you to save the rest of the country. But you wont get more then others in compensation. At least give people like this more for they endure more hardship for the sake of others.

quote: "In Tak Province, many local residents' homes, located around the dam, have been submerged under water for more than a month.

The affected locals are likely to take action to pressure dam officials to discharge more water." unquote

<<<<<<<<<<>>>>>>>>>>>

If they are living upstream of the dam and are being flooded by the reservoir waters they are obviously living within the reservoir area designated as "FSL", (full storage level) and shouldn't be there. All dam reservoirs have a Maximum Storage Level which is a NO construction zone and there are normally building restrictions within a certain distance from the MSL shoreline. If they are living downstream of the dam discharging more water will only aggravate their plight.

Exactly. Based on my internet search I would say (For Bhumibol) that there is a buffer between FSL (EL 260.00mSLE) to the main dam crest by the order of 1m. The crest elevation is at EL 261.00mSLE (meter from Sea Level Elevation). Therefore no permanent structure shall be built surrounding the reservoir below EL 261.00mSLE. A 100% storage means the dam elevation is at EL 260.00mSLE.

Edited by ResX
Posted

other places north of Thailand were getting excessive rainfall also so did they then have to release more water from their dams?

got message from a friend in Nan about heavy downpour there today and wondering whether all this water will add up to that already surrounding Bkk

There's still rain in the mountains around Chiang Mai. Tonight we have rain in the city. I road up from Lamphun along the Ping River two days ago and water was still rushing over the spillways. It sounds like water flow has been reduced out of Bhumiphul Reservoir but not stopped.
Posted

what's curious: where from so much water coming into those dams?

(does China releases more water from its own dams than usually?)

If you were being provided by hourly rainfall data for Bhumibol dam during the recent flood event, for example, I think you can see rainfall intensity as high as 35,000-40,000 cubic meter per second (Normal average probably between 100-250 cubic meter per second). If the dam operators were smart enough they could know how severe the flood over the next one month is going to be by knowing this figure ( what I usually call as 1st degree flood flow), the current storage level and how long the first degree flood flow holds. Why? Because this peak flow dictates how big and how long the more problematic low intensity but long duration 2nd degree flood flow. From the first degree peak flood flow, that may last at most 8 hours, they can construct the amount of second degree flood flow and the expected duration. This can be done accurately by using the past flood data for the same reservoir. Therefore the operator can know with almost 100% accurate whether their reservoir is going to be beaten at least 24 hours earlier. In this case typical second degree flood flow could be 3,000 cubic meter per second that could last for 7 days. It takes sometimes probably two to three months before the actual flow to go back to 250 cubic meter per second.

The 1st degree flood flow dominates by the rainfall and run-off. The second degree flood flow dominates by the flow from water shed, predominantly underground water. Therefore, even there is no rainfall, the actual river flow to a reservoir will not reduce in short period of time.

Posted

other places north of Thailand were getting excessive rainfall also so did they then have to release more water from their dams?

got message from a friend in Nan about heavy downpour there today and wondering whether all this water will add up to that already surrounding Bkk

there's a seasonal time each year when China releases water, unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

Posted

@ResX

in other words what you're saying that main reasons were rainfall water & improper water management?

@elcent

unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

you mean largest dam in Thailand or in China ?

(also if you could supply some references)

Posted (edited)

@ResX

in other words what you're saying that main reasons were rainfall water & improper water management?

@elcent

unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

you mean largest dam in Thailand or in China ?

(also if you could supply some references)

previous years Thailand negotiated about the time China should release their waters and China always co-operated. Search the archives.

This year was deaf silence.

The largest dam in Thailand was kept back for very strange reasons. The excuse made doesn't hold any logic. Search for charts at http://asiancorrespondent.com

BTW, it is even claimed that tap water is on international standard. This image from china town tap water. Just by sight one must recon that there's something wrong. Complaints about the bad smell and color are coming from all over Bkk.

http://desmond.yfrog...e=640&ysize=640

Edited by elcent
Posted

@ResX

in other words what you're saying that main reasons were rainfall water & improper water management?

@elcent

unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

you mean largest dam in Thailand or in China ?

(also if you could supply some references)

True. At best Bhumibol and Sirkit dam could hold back 7 billion cubic meter of flood waters (total). This was insufficient since the amount of flood waters that flooded Bangkok is slightly below 16 billion cubic meter. These two dams probably managed to hold far less than 7 billion cubic meter the intended flood waters.

Posted

Innocent me thought that any water from China would flow into the Mekong river. Assuming that's true, whatever the Chinese do may effect the level of the Mekong river and eventually Cambodia, Vietnam, much more than Thailand and certainly not Bangkok :ermm:

Posted

Passak dam is down about 70 cm from the highest level a few weeks ago. So they are obviously letting out more water than they are receiving.

That is an awful lot of water they could have held back.

To be fair it was rather full:

- Bhumibol Dam: it reached 99 Percent of retention capacity.

- Sirikit Dam: it reached 99 Percent of retention capacity.

- Kwae Noi Dam: it reached 100 Percent of retention capacity.

- Pasak Dam: it reached 136 Percent of retention capacity.

- Ubonrat Dam (Khon Kaen Province): it reaches 120 Percent of retention capacity.

- Lampao Dam (Kalasin Province): it reaches 100 Percent of retention capacity

http://theenergycoll...onitoring-tools

I would assume there was a risk keeping it at 136% for a longer period of time.

Beside Bhumibol & Sirkit which are other dams located within Chao Phraya catchment?

Posted

The Bhumibol and Sirikit dams have been releasing 45m m3 a day, with Sirikit 15 - 18 and Bhumibol now down to 30. I assume that means the Sirikit dam doesn't change it's release rate? Might make sense as Sirikit is an embankment dam whereas Bhumibol a concrete arch dam.

With still billions of m3 water in front of Bangkok and around it, a drop in release from 45 to 30m m3 per day doesn't sound like an awfull lot, neither as significant :ermm:

(I know the figures somehow don't seem to add up, blame to OP)

They have to create "buffers" by 1-1.5m margin for off season heavy rainfalls beside the need to discharge for power generations. They can't go any lower. I think they will try to discharge slightly more than incoming flows to create the desired buffers.

Posted (edited)

Innocent me thought that any water from China would flow into the Mekong river. Assuming that's true, whatever the Chinese do may effect the level of the Mekong river and eventually Cambodia, Vietnam, much more than Thailand and certainly not Bangkok :ermm:

you're right, my mistake. They negotiate the dry seasons with China and ask them to release more water into the Mekong.Interesting read here http://www.atimes.co...a/LH14Ae01.html

Here another from the worst flood in Laos http://www.ipsnews.net/news.asp?idnews=43828

Edited by elcent
Posted (edited)

there's a seasonal time each year when China releases water, unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

Which rivers from China run into Thai dams, particularly into the Chao Phraya basin dams?

Edited by whybother
Posted

there's a seasonal time each year when China releases water, unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

Which rivers from China run into Thai dams, particularly into the Chao Phraya basin dams?

Really only 2. The Mekong and Salawin Rivers. The Mekong is far east side of Thailand, drains into the South China Sea. The Salawin just touches a small piece in north west Thailand, but enters the Adaman Sea in Myanmar.

The Chao Phraya drainage basin area is entirely in north central Thailand.

When it rains, you get some water in instant runoff from developed areas, and delayed runoff in forested or agricultural areas. It takes time for the water to start as a trickle, flow to a stream, into a river, going from higher elevation to lower elevation. When large amounts of rain fall, there is a large delay from initial flow on land to end of flow due to plant/soil resistance. When the ground is saturated, the runoff becomes much faster, until the saturation ceases.

The rainfall that created this flood was very heavy. Better water management would have helped some up until the time the dams become critically full. It's a question of flood me now, or flood me later. This volume of water that fell greatly exceeded the natural capacity of the Chao Phraya basin. Flooding would have been bad anywhere along the river and the delta, with or without dams, as it has in the past, and will, no doubt, in the future.

Even in Thailand, drought or flood is not unusual. Dams help store water in drought, generate electricity, and help control floods. Massively excessive rainfall overwhelmed the dam capacity. This flood does not have simple solutions, but better planning could have prevented a bunch of the damage.

In the old days, floods would spread silt to the farm fields and revitalize the land. Today, water control keeps the silt from the fields, and necessitates the use of fertilizers.

Ever wonder why a lot of traditional Thai homes are elevated?

Posted

there's a seasonal time each year when China releases water, unfortunately at the same time the largest dam got order to hold when it should have been released. As if on purpose.

Which rivers from China run into Thai dams, particularly into the Chao Phraya basin dams?

Really only 2. The Mekong and Salawin Rivers. The Mekong is far east side of Thailand, drains into the South China Sea. The Salawin just touches a small piece in north west Thailand, but enters the Adaman Sea in Myanmar.

The Chao Phraya drainage basin area is entirely in north central Thailand.

<snip>

Yep. Thanks. That's what I thought. So "elcent"s comment on China releasing water is irrelevant in relation to the floods in Bangkok.

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