BMA: Slow drainage caused by subsidence

Twenty-nine areas in Bangkok were flooded following heavy rain on Wednesday night, causing severe traffic congestion across the city, and the water took many hours to drain away.

Deputy city clerk Jumpol Sampaopon said on Thursday that work crews took a long time to drain off the water because subsidence in the city means the canals now have only a gradual drop and the water flows out much more slowly.

Land in the city was subsiding at a rate of one to 10 centimetres a year, he said.

Mr Jumpol denied that the flooding was caused by undredged canals or clogged drains, as many people claimed.

Responding to former Bangkok governor Bhichit Rattakul's suggestion that all the drains in the capital city should be replaced with new ones, the deputy city clerk said the task would be difficult and would require a large budget.

However, he said, Bangkok authorities might lay new drains in some flood-risk areas.

Officials will ensure that the drains are not clogged with debris such as leaves, sticks and garbage so that water can flow unobstructed, he added.

Sujarit Koontanakulvong, a water engineer at Chulalongkorn University, said rainfall is an important variable for flooding in Bangkok.

"The drainage system has been in use for more than 20 years and it is designed to handle 60 millimetres of rain per hour," Assoc Prof Sujarit said. "If there is more than 130mm of rain in an hour, it will take more than two hours to drain off."

He also suggested that the Bangkok Metropolitan Administration install more drains and speed up the draining process on main routes in the city.

"The BMA should consider setting up an electrical drainage system. This system is a central public utility system which each agency can operate together," he said.

Meanwhile, Rak Thailand Party leader and MP Chuvit Kamolvisit posted a question in his Facebook page on Thursday asking whether the BMA's giant tunnel can really be used to drain water out to the sea.

His question was directed to Bangkok Governor MR Sukhumbhand Paribatra.

"I want to know whether the giant tunnel, in which a huge sum of money was invested for sustainable flood prevention, is really effective.

"An official working at the BMA office told me that the city's water pumps and water pumping system were full of defects, making the BMA's water pumping capacity ineffective," Mr Chuvit posted on his Facebook page.

The Rak Thailand leader suggested it was time that people started looking into various projects of the BMA to see how much it had actually done to prevent Bangkok from being flooded.

Mr Chuvit also posted a picture taken last year of a flooded spot in Bang Khae area.

The picture shows how sad and disappointing it was that when Bangkok was hit by the great flood, the giant tunnel could not be of any help, he said.

Share your thoughts

Discussion 1 : 27/09/2012 at 05:52 PM
@D20 Banmebkk :Thanks for the info, good to see we are not near to 10 cm per year, maybe he meant mm, sometimes units and numbers gets mixed up here in the Kingdom. @D18 jck Agree and I think there will be foreign experts involved as the companies that are going to bid for the 350 Bn contracts on flood prevention project are all foreign or joint ventures, so the expertise will be brought in for sure.
Discussion 2 : 21/09/2012 at 01:33 PM
@Disc 15 khunbj - Bangkok is in fact sinking each year, that is why they banned the practice of pumping water from wells over a decade ago. The subsidence has probably slowed quite a bit. By looking at my old factory, the land subsided around 20-30cm over a 22 year period.
Discussion 3 : 21/09/2012 at 07:42 AM
Khun BJ #17, I use to live in Phare, and every year, we had a flash flood for 2 or 3 days (as a result of massive deforestation), and then, it was over. Wanna guess where those water went and ended up at? Of course, BKK, through one of the 4 rivers system that made up the mighty Chao Praya River, flowing down through the heart of BKK on its way to the Gulf of Thailand. Once the water exits the North, it will either continue to flow southward, or overflowing the river banks, spilling, into the central plain. Also, let me remind you that the Bhumipol Dam up north is 600 meter above sea level, compare to BKK's 1 meter average above sea level. I hope you got the picture!
Discussion 4 : 21/09/2012 at 07:15 AM
In technically complex industries such as oil refining and petrochemicals when adequate Thai expertise is not available foreigners from the parent companies are brought to Thailand to assist in design of new facilities or problem solving and in so doing transfer knowledge and expertise to Thais. Is in not time foreign expertise and help be sought to address water management in Thailand? Politicians are clearly not qualified in this field.
Discussion 5 : 21/09/2012 at 07:03 AM
Spicemen : Oh I see, so the high tide does only affect the Bangkok area and not the rest of the river , interesting, do you care to elaborate a bit further ? Would you believe it or not but any area flooded by the rivers is barely above sea level (also in the North) or du you suggest gravity does not work in the same way in Bangkok and in the North or what is the point ?
Discussion 6 : 21/09/2012 at 06:59 AM
The real cause of the flooding is the massive burning and clearing of watershed lands by greedy people contract farming for a quick profit and no regard for the result of their actions on the lives of others. This wholesale waste of the mountain watersheds of the east, west and north must be stopped and real long term reforestation begun to ever control the flooding.
Discussion 7 : 21/09/2012 at 06:54 AM
Could BP please do a bit investigatory work and determine whether or not Bangkok is sinking up to 10 cm per year...this is going to be a major disaster, that is if it is true and should be front page news .
Discussion 8 : 21/09/2012 at 06:50 AM
The rational next step is to hire the best flood engineers in the World as temporary consultants. They would likely come from Holland, parts of which are below sea level. They have successfully fought flooding for years, let them assess the situation and propose solutions. Arrogance should not prevent bringing in the best expert help from outside when necessary.
Discussion 9 : 21/09/2012 at 06:06 AM
Khun Androidl #11, unlike the North, BKK is barely above sea level, so draining massive volume of water is always a challenge. On top of that, you have floodwater coming down from the North, and high tide condition, all of which the North doesn't have to deal with. Besides, the BKK Governor is elected by BKK people, so why don't we let them judge their own elected Governor through elections?
Discussion 10 : 21/09/2012 at 05:50 AM
Last year,just before the great flood, they came to dredge the drain in my mooban, all 15 or so of them, mostly women, and they started to work around 10am after a long and noisy breakfast. By noon, they all left because not a single manhole cover could be open by those women who came without proper tools, leaving a mess outside my house that I'd to clean it up myself. The next day I called the Suan Luang office to report and the guy said he'll look into it. That was over a full year ago, and we are still waiting.
Discussion 11 : 21/09/2012 at 04:35 AM
Flooding outside bangkok is PT government's fault. Flooding in bangkok is nobody's fault. Double standard view point for the dem lovers.
Discussion 12 : 21/09/2012 at 03:16 AM
Discussion 9 : I think you just nailed a new short LOL:e.. Land Of Lame Excuses to be used along with TiT.
Discussion 13 : 20/09/2012 at 10:49 PM
This is the land of lame excuses, incompetence and corruption zero to none.
Discussion 14 : 20/09/2012 at 10:38 PM
Each rain fall has been uncharacteristically long in duration .The elevation is too low for quick drainage .It isnt that hard to understand is it ?
Discussion 15 : 20/09/2012 at 09:59 PM
Bangkok has had many floods regularly over the past many decades. Each time plans materialize and large sums of Thai tax-payer money is allocated to solve the problem and “once-and-for-all” fix the drains but never with any success. The only thing that “goes down the drain” is the huge sums of money with little to show for it and no accountability.
Discussion 16 : 20/09/2012 at 09:15 PM
"Land in the city was subsiding at a rate of one to 10 centimetres a year, he said." So: As much as 1 Metre in a decade. In 20 years... in 30 years... in 50 years! At what point will Greater Bangkok be so far below sea level as to make it necessary to move to higher ground? I know, I know, in places like New Orleans, Houston, Florida (most of the state), they'll defend their right to stay in place 'til they drown. Must the Thai people follow those lemmings?
Discussion 17 : 20/09/2012 at 09:13 PM
Last year it was the governments fault. This year it is the rains fault. We need someone who can fix the problem.
Discussion 18 : 20/09/2012 at 08:03 PM
One thing for certain some of the 350 billion will be siphoned of to rectify this problem.Hard lines the rest of the country.
Discussion 19 : 20/09/2012 at 08:02 PM
I wonder how many years and how many floods it will take before the citizens of Bangkok forget their pride and demand that a Dutch engineer is placed solely in charge of all Bangkok flood protection. I will probably be at least another decade, but it will eventually happen :-)
Discussion 20 : 20/09/2012 at 06:52 PM
And they have just found this out.350 billion up for grabs to make it work!!!When will you realize how incompetent the people are in charge of your safety and well being.
Discussion 21 : 20/09/2012 at 06:06 PM
One hopes that the Deputy City Clerk's claim that the flooding was not caused by undredged canals or clogged drains is correct. It certainly should be put to the test and the sooner the better.

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