Somkiat Prajamwong, secretary-general of the Office of the National Water Resources (ONWR), said a joint task force centre will be set up at the Royal Irrigation Department with officials to analyse information on the situation at reservoirs nationwide around the clock.
He said that 11 major dams need to be monitored as they are expected to reach the limit of their storage capacities in one month. Of them, two large dams – the Nam Oun dam in Sakon Nakhon and the Kaeng Krachan dam in Phetchaburi – are almost full or about 80-90% of capacity and they need to be drained at a faster rate, Mr Somkiat said.
The Department of Disaster Prevention and Mitigation and the people who stand to be affected by the drainage will be informed three days in advance so they can prepare to deal with the impact, he said. The overall water situation remained at yellow alert, which denotes readiness, Mr Somkiat said.
He said a close watch is being kept on more than 50 middle-sized dams in the Northeast which are now filled to capacity to assess storage needs and release of dam water. Local governing bodies have also been instructed to handle water management at more than 1,000 small reservoirs, he said.
Mr Somkiat also revealed that overall water volumes measured on May 1 were higher than those during the 2011 deluge, though such high amounts were found only at some major dams such as the Bhumibol and Sirikit dams and they were still manageable.
Water management measures are also put in place for the Central Plains region as the Meteorological Department predicted further rainstorms in the middle of the month, he said. He added that floodwater drainage was being stepped up in provinces along the Mekong River as water levels in Ubon Ratchathani came down, but Loei, Nakhon Phanom and Mukdahan have still seen water rise to 70 centimetres to one metre, probably due to water discharges from China and Laos.
Deputy Prime Minister Chatchai Sarikulya said yesterday (Aug 2) that he had ordered all dams and reservoirs to be drained one month in advance. However, water levels remained unusually high at several dams because rainstorms recently moved in and dumped more rain, filling some dams with up to 30 million cubic metres of water in only one day while discharges were only 2-3 million cu/m per day.
Asked about the influence of a new storm predicted to move in tomorrow (Aug 4), Gen Chatchai said the ONWR’s secretary-general will now work at the Smart Water Operation Centre at the Royal Irrigation Department 9RID) to follow the situation and provide him with updates. The minister stressed the need for agencies to inform people about how they will be affected by water drainage and to prepare for evacuation.
Asked if Bangkok would face floodwater similar to the 2011 deluge, Gen Chatchai said water run-off from the North will be the major factor. But currently, flooding has taken place largely in the Northeast and the West and water volumes in these regions would not have any effect on Bangkok.
RID director-general Thongplew Kongchan said all 35 large dams nationwide currently have a combined water volume of about 48.9 billion cu/m or 69% of storage capacities combined. The RID has put in place reservoir regulation procedures or a rule curve to manage the release of water. Dam safety measures have also been put in place to inspect the integrity of dam structures, he said.
RID deputy director-general Thaweesak Thanadechopol said five provinces in the Northeast – Yasothon, Roi Et, Ubon Ratchathani, Nakhon Phanom and Sakon Nakhon – had been affected by flooding triggered by heavy rain.
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