A few days ago I suggested that the primary cause of flooding in Thailand this year is exceptionally high rainfall. While not denying “man-made” issues, such as dam management, I argued that insufficient attention is given to the very high rainfall that has fallen throughout the Chao Phraya catchment. To support my argument I provided some graphs comparing 2011 rainfall (January – September) with the historical averages for a number of locations in northern Thailand.
As some readers have comments, simply comparing 2011 rainfall with the average does not give a good idea of just how exceptional (or not) 2011 has been. This is a very good point, and I am collecting some historical data to explore this issue.
Here is a very preliminary analysis based on some historical data that I have for Chiang Mai, from 1914 to 1995. I obtained these data about 10 years ago from the Royal Irrigation Department.
The average for January-September rainfall over this period was 971 millimetres. The graph shows the year by year variation from the average (click for a larger image). So, 1915 was about 40 percent below average, while 1918 was about 30 percent above average.
2011, shown on the far right of the graph has been about 42 percent above average for January to September. It is easy to see from the graph that this is exceptional, occuring only in 1942, 1953, and 1970.
For flood watchers in Thailand 1942 should ring a bell. If it doesn’t, this is a good reminder:
Of course, just because there is heavy rain in Chiang Mai, doesn’t mean it will flood in Bangkok. I’ve had a quick look but I haven’t been able to find references to flooding in Central Thailand in 1953 or 1970. What seems particularly exceptional about 2011 is that rainfall has been well above the average in many areas throughout the Chao Phraya catchment. As I reported in my previous post, 2011 rainfall in Lamphun has been 96 percent above average, in Lampang 77 percent above average, in Uttaradit 53% above average and in Phitsanulok 46% above average.
I will try to explore the extent to which this has occurred before in another post some time next week.
This is some very preliminary analysis of only one data series. But it does suggest that some more attention to the exceptionally high levels of rain that have fallen during the 2011 wet season – rather than jumping too quickly to the politics of blame – may be warranted.
Isn’t the 2011 problem the notion that Bangkok is now not prepared for (or willing to accept) a flood such as the 1942 flood?
0
0
Under these current exceptional ‘dire’ circumstances, an exceptional Thai leader is required with urgency. Yingluck has failed miserably to rise to the occasion.
Only Thaksin S. could save us now.
. . . . . .
(just kidding)
0
0
Some said because the ‘monkey cheeks’ area that were designed to divert water from the north had been used up for Suvannabhumi Airport.
Some said because the co-incidence with super high tide of this year plus a lot of rain.
Some said the information was not communicated well throughout the management process.
So many info out there. But I like the video you post here ^_^ Thanks.
0
0
My idea is that disasters are never natural, and human activities greatly have influence on what happens, specially if related to management of soil, land use, city and landscape planning. And maybe we better start having a closer look to multipurpose dams that are disseminated in all Southeast Asia. But i just want to pinpoint to some maps I came across.
http://www.arcims.tmd.go.th/dailydata/MonthRain.php
0
0
Pino Stricccoli 4
“My idea is that disasters are never natural”
Try telling that to the dinosaurs…
0
0
Incredible footage. Thanks for sharing!
0
0
[…] has had more rain this year. On this latter topic, New Mandala has had three posts here, here, and here. In the previous post, BP looked at the accumulated rainfall at the end of September […]
0
0
According to a Thai Hydrogolist from a BKK University, I forget his name sorry…
The 1995 Thai flood had about the same amount of water as the 2011 flood…
The 1942 flood had 4X the amount of water, compaired to the 2011/1995 flood, to deal with and BKK had only about 1+million people…
During the 2010 flood, The ‘Red Shirts’ sued the Abhisit Government for malfesance (Article 157), in controlling the flood waters…
I’m assuming that the Democrats are not doing this, because they do not want the Thai people looking too close to the handling of the Flood Control assets, prior to Yingluck assuming office in Aug 2011…
Though there is a University Lecturer that is bring a ‘Class Action’ sue against the Thai government…
According to Thai fiscal records. Historically Thailand reinvests about 10% of their GDP into infastructure. During the Thai Military and Democrat rule, this DROPPED to 5% annually…
Now you know a little more background, concerning why the floods were so bad…
0
0