'Big Bag' holds key to ending city crisis

However, Thon Buri residents would face a month of floods and should therefore be prepared, he added.

Following yesterday’s Cabinet meeting, PM’s Office spokeswoman Thitima Chaisaeng reported that water levels were under control, with the Chao Phraya River flowing at 3,195 cubic metres per second in Nakhon Sawan on Monday and Ayutthaya’s Asia Highway returned to normal. She added that Prime Minister Yingluck Shinawatra, following her order that the Khlong Sam Wa sluice gate be opened by a metre, had said that if they could get through this week, everything would be alright.

Arnon, director of the Geo-Informatics and Space Technology Development Agency, said that flood levels in Don Muang, Lak Si and Bang Khen were stable, although the water was spreading. The “Big Bag” barrier would stop more water pouring in, he said, but as the Rama 9 drainage tunnel was so far away, it could take another week for the area to dry. However, western Bangkok’s Thon Buri would face another month of flooding from Khlong Mahasawat, which is helping drain the inundation from Ayutthaya, he said.

This week, the Royal Irrigation Department will repair floodwalls from Ayutthaya down to Pathum Thani and Nonthaburi, so the next round of high tides should be dealt with more effectively. Arnon said that if they could get through the high tides mid and late November, most areas would start to dry and could begin the process of rehabilitation.

In his capacity as secretary for the committee for water management in flood-hit areas, Arnon said that about 12,000 million cubic metres of water remained in farmland from Sukhothai southwards while only 3,000 million cubic metres were flowing in rivers and canals to Bangkok, with a total of 4,000 million cubic metres already drained into the Gulf of Thailand.

Arnon said that unless there was heavy rainfall in the North, water levels would rise at stable and slow rates. 

The National Flood Relief Operation Centre (FROC) dispatched officials and soldiers to build the 3.5-metre-long U-shape “Big Bag” floodwall from the mount of Premprachakorn Canal to Pathum Thani’s Tambon Lak Hok on Monday night with expectations that work be completed by yesterday to prevent floodwater pouring into the waterworks canal and also stall strong-current floodwater from flowing through Bangkok’s Don Muang district. The flow of floodwater from Rangsit Canal through Paholyothin Road was stable at less than 15 million cubic metres per day and the canal level was decreasing by 1cm per day. If the water level in the canal reduced to 50cm, most of Bangkok would be safe, he added.

With Klong Sam Wa sluice gate lifted, officials could now control water via the Khlong 8 and Khlong 9 sluice gates, hence people would experience slight flooding, Arnon said. Yingluck urged officials to tackle the crisis systematically and to control water at key spots so that levels would not exceed the critical marks, while implementing the Royal Irrigation Department’s measures.