Dam will not collapse, EIT vows

[webfact]

Dam will not collapse, EIT vows
Nisanart Kangwanwong,
Pratch Rujivanarom
The Nation

Fears mount over Mae Suai Reservoir cracks

BANGKOK: -- THE ENGINEERING Institute of Thailand (EIT) has joined other agencies in trying to ease public concern over the safety of the Mae Suai Reservoir in Chiang Rai province in the face of earthquake fears.

Fears of an earthquake have deepened after a 6.3-magnitude quake hit the province on May 5 last year and hundreds of aftershocks followed, causing some cracks in the structure.

"It can withstand a quake with a magnitude of up to seven on the Richter scale," Anurak Chuchern said yesterday in his capacity as the overseer of the dam.

Constructed in 2003, the dam is located in Chiang Rai's Mae Suai district. It started storing water in 2014.

"False rumours have been spread that as a result of the cracks the reservoir will burst. Many locals have relocated away from the reservoir's neighbourhood," Anurak said.

He said relevant agencies had dispatched engineers to inspect the reservoir several times in response to the concerns of locals and they found that the structure was secure.

"But we are in the process of improving the reservoir further so as to boost public confidence in its safety," he said.

EIT vice director Suttisak Soralump told a press conference yesterday that the 6.3-magnitude earthquake caused only slight damage to the reservoir.

"That damage definitely can't bring down the structure," he said, having inspected the reservoir recently.

"The cracks on the top concrete part of the dam have existed since the dam was built and causes some water to leak when the water level in the dam is high.

"They were caused by the concrete part and earth part of the dam sinking at different rates. The earthquake only made new cracks on the concrete blocks."

Despite the assurances, Assoc Prof Suwattana Thittaladakorn, the EIT's expert in water-resource engineering, said the damage would have to be fixed to make people feel safe.

Suwattana also said locals would have to be prepared in the event of another earthquake occurring and an early-warning earthquake system would be installed.

The EIT examined the reservoir after the safety concerns caused a rift between the Royal Irrigation Department and locals.

Source: http://www.nationmultimedia.com/national/Dam-will-not-collapse-EIT-vows-30253947.html


-- The Nation 2015-02-13

[Bluespunk]

""The cracks on the top concrete part of the dam have existed since the dam was built and causes some water to leak when the water level in the dam is high."

Not surprising the local community has concerns then.

[thesetat2013]

The last quake to hit was 6.3. It doesn't take an idiot to realize that it is not improbable that a quake could hit at 7.0 which is their standard for this dam. These people are justified in their fears. They need to do something about the problem instead of trying to reassure these people about it being so safe.

[PatOngo]

[jcisco]

6.3 is rather strong, and remember that a 7.3 is 10x more powerful... so they are quite up there in the power levels. I'd of thought if there was any risk of flooding due to sudden release they least they could be done would be to ensure no one is living in the most dangerous locations and no major roads or infrastructure is going to be drowned or under silt.

[Reigntax]

6.3 is rather strong, and remember that a 7.3 is 10x more powerful... so they are quite up there in the power levels. I'd of thought if there was any risk of flooding due to sudden release they least they could be done would be to ensure no one is living in the most dangerous locations and no major roads or infrastructure is going to be drowned or under silt.

The difference between 6.3 and 7.3 is 30 times the release of energy and 10 times the shaking graphical amplitude, magnitude or moment.

Edited February 12, 2015 by Reigntax

[retell]

Hit a concrete wall with a small hammer once nothing happens keep hitting it and it will break eventually

[Reigntax]

Hit a concrete wall with a small hammer once nothing happens keep hitting it and it will break eventually

s

That may be so if hit with a hammer but not if subject to to normal expected design loads or forces such as an earthquake.

Assuming it is reinforced correctly, no design allowance would have been made for tensile forces imposed on the concrete so as long as the tensile force remains within the elastic range of the reinforcement there should not be a problem, except for degrading by long term corrosion.

If the yield strength of the reinforcement has been exceeded, this will result in permanent deformation but not necessarily failure.

My concern would be the statement that some sections have settled greater than others as this suggests the structure has not been founded correctly and the earth or rock reactive loads have not been adequately assessed for the imposed loads.

[siampolee]

I am no technician, however I am of the opinion that if the structure is cracked there has to be an area or areas of weakness inthe structure.

Now whether that weakness is visible or not perhaps remains to be seen either by a visible increase in damage i.e. more cracks appearing or a fatal failure breakdown of the dam wall structure.

Those cracks in the structure will allow water to flow, water over time has some very destructive and in this case possibly unseen damage is being slowly created.

Now if these ''experts'' are indeed so confident in the strength of the dam and of course their own expertise, might it not be a splendid idea to house them in the area of the dam structure so as they can continually monitor the situation?

Being on hand would indeed save time and money as well as the ''experts'' being able to monitor progress on a daily routine coupled with the delights of rural living in a ''safe area'' would indeed be immense,indeed paradise personified.

Or perhaps in easy language. '' Hey experts,put yourselves and your money where your mouth is.''

[MESmith]

I thought all the reservoirs were low now & drought on it's way.

No need to worry chaps. Mai pen rai...

[berybert]

The last quake to hit was 6.3. It doesn't take an idiot to realize that it is not improbable that a quake could hit at 7.0 which is their standard for this dam. These people are justified in their fears. They need to do something about the problem instead of trying to reassure these people about it being so safe.

Its a bit like trying to crack a rock. The first 10 hammer hits wont crack it. but the 11th one will

What that means is if this dam gets hit enough times by 6.0 quakes it will be a less than powerful 7.0 that finishes it off.

[Reigntax]

The last quake to hit was 6.3. It doesn't take an idiot to realize that it is not improbable that a quake could hit at 7.0 which is their standard for this dam. These people are justified in their fears. They need to do something about the problem instead of trying to reassure these people about it being so safe.

Its a bit like trying to crack a rock. The first 10 hammer hits wont crack it. but the 11th one will

What that means is if this dam gets hit enough times by 6.0 quakes it will be a less than powerful 7.0 that finishes it off.

Depends on the dam design and whether we are referring to serviceability failure or catastrophic failure.

Service failure is where e dam is no longer capable of its intended or design purpose but still has sufficent strength not to completly fail.

However, given the seismic activity that has already occurred, it is possible that a quake far greater than the design may happen at any time. But this relates to every structure, as you can only design for known or expected conditions which in the case of this dam to date, have not been exceeded.

[canuckamuck]

6.3 is rather strong, and remember that a 7.3 is 10x more powerful... so they are quite up there in the power levels. I'd of thought if there was any risk of flooding due to sudden release they least they could be done would be to ensure no one is living in the most dangerous locations and no major roads or infrastructure is going to be drowned or under silt.

The dam is built about 2k upstream from a major highway, the town of Mae Suai, and the village of Din Doi . So too late to make sure no one is there

I noticed that this year they did not let the reservoir fill up, like they did the last two years. Even though in our area the rainy season was near normal. as opposed to most of Thailand. This dam is about 12 years old, I believe.

[Carl64]

If they say there is nothing to worry about.......RUN

[lannachiangrai]

After the earthquake I went up and inspected the dam and did not see anything indicating structural damage however if there is a year of extremely heavy rainfall and the dam reaches capacity, it will be frightening because the cracks mentioned in the article are near the very top of the dam.

[givenall]

I think Swatting should move and live with his family near the dam on the lowest area. That would give conference to the residents

[trainman34014]

If Thai engineers are saying it's not going to collapse then the best thing to do is.......RUN !

[willyumiii]

Tempting fate.

Time to move to higher ground!

[alantheembalmer]

"Constructed in 2003, the dam is located in Chiang Rai's Mae Suai district. It started storing water in 2014."
I take it this means that construction started in 2003, and the dam was operational from last year? Or was it constructed in 2003, and they were leaving it to "settle", or whatever dams do, for 11 years?

[Don Aleman]

MOVE AWAY FROM THE DAM !

[klauskunkel]

Just check if the contractor is still in Thailand, that should be your indicator

[siampolee]

I remember this movie from my younger days (what a memory ),I do hope there isn't going to be a remake here at any time using reality as the base of the remade movie.

Edited February 13, 2015 by siampolee

[toybits]

I get more uneasy when they say it won't happen. Easy for them to say that.

[HuaHinHim]

Wow that's deep

Hit a concrete wall with a small hammer once nothing happens keep hitting it and it will break eventually

[cumgranosalum]

There's "collapse" and then there's "unacceptable leakage".......

[canuckamuck]

"Constructed in 2003, the dam is located in Chiang Rai's Mae Suai district. It started storing water in 2014."

I take it this means that construction started in 2003, and the dam was operational from last year? Or was it constructed in 2003, and they were leaving it to "settle", or whatever dams do, for 11 years?

The first time I saw the reservoir was 2005 it had water in it then, The first time I saw it full to the top was 2011, so that is a mistake in reporting

[wgdanson]

Is there really an early-warning system for earthquakes? If so, why didn't they have one in Hait, SanFrancisco, Japan or anywhere.

[uptoeleven]

> Is there really an early-warning system for earthquakes?

no.

Correction - there are plenty of them. But none that work.

2nd correction - there are some that work some of the time and they're pretty idiosyncratic. For example it is thought that many animals can detect the changes that occur in rocks in the days and weeks leading up to an earthquake, before the fracturing starts. They will often get skittish and try to escape. But it's not reliable. There are two fundamental problems with earthquake predictions around dams.

The first problem is that no-one knows the precise nature of the rocks that are under tectonic stress, what depth / pressure they're at, what their fracture point is, what processes are at work in that precise area. So we can't even model the conditions accurately.

The second problem is that - just as you use oil to lubricate the moving parts in a car, there is a lubricant for rocks - for tectonics. Unfortuately that lubricant is water and in dams there can be substantial quantities of it. Which means you're filling the dam with the one thing that you REALLY don't want getting into the rocks underneath. Water is great because (at pressure) it will selectively dissolve certain minerals and deposit others. At depth, under pressure, water is the principal actor in geochemistry as well as its huge role in facilitating tectonics, so basically stuff going on under the dam is probably affected by the presence of the dam itself.

Dams in some parts of the world will be tectonically more stable than others. For example dams in the North of England are pretty stable. That's because the most recent "orogeny" (mountain-building) that went on there and caused the uplift that formed the Pennines, was the Alpine orogeny some 24 - 25 million years ago. Most of the mountains of the alpine orogeny have been eroded and weathered away, hence the presence of much older, underlying rocks in the North of England.

Dams in S.E. Asia will be in much younger mountain ranges - or at least mountain ranges where there is a lot more current tectonic activity - which means the rocks are already under pressure. Adding a bunch of water on top is only going to keep things moving that much quicker :S

[halloween]

After the earthquake I went up and inspected the dam and did not see anything indicating structural damage however if there is a year of extremely heavy rainfall and the dam reaches capacity, it will be frightening because the cracks mentioned in the article are near the very top of the dam.

The water at the top of the dam exerts relatively little pressure compared to that at the bottom.

[Traveling Sailor]

"It can withstand a quake with a magnitude of up to seven on the Richter scale," Anurak Chuchern said yesterday in his capacity as the overseer of the dam.

However, his assessment is based on the supposition that the dam was built to specs.

Since there do not seem to be any quality control inspections on large or small projects here, who knows what kind of shoddy workmanship or sub-standard materials went into the construction of this project?

I, for one, would not want to live down-stream of this project. Disaster waiting to happen???