How long will the floods in Thailand last?By Bangkok Pundit Oct 24, 2011 8:00AM UTC
Authorities have taken measures to divert floodwaters flowing from the north away from the city and into the Gulf of Thailand, but the capital was on tenterhooks because of the possibility of heavy rainfall into canals and rivers already full to the brim.
Prime Minister Yingluck Shinawatra said authorities were doing everything possible to drive the water out, but were facing a race against time.
“Water is coming from different places and headed in the same direction. We’re trying to build walls but there will be some impact on Bangkok,” Yingluck told reporters, adding that high tide in the Gulf by the end of the week could complicate the situation.
The threat that floodwaters will inundate Thailand’s capital could ease by early November as record-high levels in the river carrying torrents of water downstream from the country’s north begin to decline, authorities said Sunday.
Bangkok’s immediate prospects remain uncertain, however, as the front lines in battling the flood from north, east and west of the city draw closer daily.
The relatively rosy longer term projection from the Flood Relief Operations Center came just a day after reports that Bangkok’s main Chao Phraya river was overflowing its banks and at its highest levels in seven years.
People should not be too concerned because the spillover could be drained, said the center’s chief, Justice Minister Pracha Promnok, in a televised news conference. He also said water in an overflowing main canal in Bangkok was receding, and drainage efforts east and west of the city were working well.
Some flooding on Bangkok’s outskirts was expected after Yingluck ordered floodgates opened Thursday in a risky move to drain the dangerous runoff through urban canals and into the sea. Nobody knows with any certainty to what extent the city will flood.
In a weekly radio address Saturday, Yingluck said that “during the next four to six weeks, the water will recede.”
Science and Technology Minister Plodprasob in an interview with Post Today that was translated by the Bangkok Post:
About 20 billion cubic metres has fallen this rainy season, and [by Wednesday] the government was able to drain about 8 billion cubic metres into the sea.
At least 10 billion cubic metres have yet to be drained.
It is not true to say, as the Irrigation Department chief did recently, that the biggest mass of water has already passed Bangkok.
There is still a huge mass of floodwater in the fields of several provinces including 3.9 billion cubic metres in Nakhon Sawan and 4 billion cubic metres in Ayutthaya. So it can be said that about 10 billion cubic metres of flood water is still threatening Bangkok.
[BP: - he then talks about water management and Suphan Buri, but that is for another post]
We have now finished dredging, which should help propel the water to the sea at the rate of 30 million cubic metres a day, using 99 water pumps.
Right now the government can propel the water into the sea through all channels at the rate of about 400-500 million cubic metres a day.
There are still 10 billion cubic metres, which will take about 20 more days to drain.
It depends on each area’s topology. If it is a low-lying area, the water can be 1-2 metres deep.
If it is higher, the water may be only 50cm deep.
People living in outer Bangkok, to the west and east, must accept the fact they live in low-lying areas with no protection.
They will have to live with floodwater for some time, and move their belongings to higher ground.
Bangkok is likely to have floods for about 2-4 weeks.
We know we can propel the water to the sea at the rate of 400-500 million cubic metres a day using pumps and boats propelling water at the river delta.
She denied that she was acting on someone’s command. “I have not got been ordered by anyone, although I get advice from many sources. We now need to brainstorm to release the 10,000-plus million cubic metres of water into the sea as soon as possible. We can’t allow the water to mass up and attack Bangkok,” the banned politician said.
The PM on how this could vary as per The Nation:
The problem was especially difficult to solve this year due to one unknown variable – the amount of rainfall.
She could not estimate the amount of water that might flood Bangkok because the country might still be hit by more storms.
Now, on when Bangkok will flood, see the Bangkok Post:
Seree Supharatid, director of the Disaster Warning Centre at Rangsit University, warned that unless the BMA completely opens its inner sluice gates to relieve pressure along key outer canals, flooding could break out across the capital. Khlong Rangsit is simply unable to cope with the water coming into the city from Ayutthaya, he said.
“If the BMA does not open all the sluice gates, the water will simply overflow Khlong Rangsit, affecting Vibhavadi Rangsit Road, Don Muang, Lak Si, Thung Song Hong all the way to Bang Khen,” he said. “To the east at Khlong Hok Wa, so long as the water cannot flow naturally, it may overwhelm the city flood barrier to flood Kaset-Nawamin, Rarm Intra and Lat Phrao.”
Dr Seree predicted widespread flooding within the next four to five days, as water from Nonthaburi’s Sai Noi and Bang Bua Thong districts race through Taling Chan on the Thon Buri side of the city.
Another major test is expected between October 28 and 30, when seasonal high tides flow up the Chao Phraya, meeting run-off water from the north.
BP: So in conclusion, sometime this week the level of flooding – as a number of parts on the outskirts of Bangkok already have some level of flooding – will increase and should peak between October 28-30. According to the Meteorological Department, only scattered showers and morning mist predicted over the next week for Bangkok so if still holds and the rain for areas around Bangkok is also limited then the flood waters will likely last around 2-4 weeks for Bangkok, but could last another 2 weeks depending on whether there is more rain than expected.