Flooding will impact Bangkok communities along the Chao Phraya River starting today, with water continuing to rise through Tuesday, city hall said.
Nine Central Plains provinces also were warned about imminent flooding after the Pasak Jolasid Dam increased its water discharges.
The Thai Meteorological Department has forecast that a monsoon trough will move across the lower Central and upper South regions, bringing heavy rain and runoff that will flow into the Chao Phraya Dam in Chai Nat.
Water will rush into the dam at 3,200 cubic meters a second (cms), outstripping usual dam-discharge rates. To preserve dam integrity, the Royal Irrigation Department has been forced to increase the amount of water it vents into the river and divert into irrigation canals.
Bangkok Gov. Aswin Kwanmuang said the hope is that water diversion can allow the discharge rate to return to a more manageable 2,700 cms.
More runoff, however, is pouring into Lop Buri’s Pasak Jolasid Dam, which is now dumping up to 1,200 cu. meters a second and rushing into Ayutthaya’s Bang Sai District at a white-knuckle 3,200 cms.
The result? Downstream rivers and canals will rise 2.3-2.9 meters through Tuesday, Aswin predicted.
He said city hall is monitoring the situation, checking the strength of 79 kilometers of embankments on both sides of the river and piling sandbags even higher. All 97 water-pumping stations along the Chao Phraya also are ready.
However, residents along the Chao Phraya and the Bangkok Noi and Mahasawat khlongs had better prepare to be inundated.
A total 239 homes in 11 communities sit outside embankments in Bang Sue, Dusit, Phra Nakhon, Samphanthawong, Bang Kho Laem, Yannawa, Klong Toei, Bangkok Noi, and Klong San districts, the governor said. All have been warned to move their valuable to higher ground.
Central Plains Soggy
Meanwhile, nine provinces in the Central Plains have been told to prepare for flooding from the Pasak Jolasid Dam discharges.
Samroeng Saenphuwong, secretary to the National Water Command, said riverside communities in Chai Nat, Sing Buri, Ang Thong, Lop Buri, Ayutthaya, Saraburi, Pathum Thani, Nonthaburi, and Bangkok all are in peril of flooding.
Prime Minister Prayut Chan-o-cha claimed on Thursday the situation was still manageable. But he also said earlier that flooding this year wouldn’t be a concern.
Flooding has affected more than 200,000 households in 31 provinces over the past week and persists in 18 provinces to the north of Bangkok. It will take another two weeks for water levels to return to normal, but only if no more major storms roll in during the last, and heaviest, weeks of rainy season.