The Royal Irrigation Department (RID) has warned provinces along the Chao Phraya River to brace for a greater risk of flooding as the Chao Phraya Dam in Chai Nat will now up its rate of discharge rate to prevent it from overfilling.
The provinces concerned are Sukhothai, Ayutthaya, Pathum Thani, Nonthaburi, Bangkok and Samut Prakan, said Thawisak Thanadechophon, deputy director-general of the RID, on Tuesday.
With a fresh period of heavy rain forecast to begin today and continue into Sunday in almost all parts of the country, the amount of run-off flowing into main rivers and dams in upper Thailand is consequently expected to rise, he said.
The Chao Phraya Dam needs to raise its discharge rate to 2,000 cubic metres per second from tomorrow from its present rate of 1,800 cubic metres per second, he said.
As a result, the water levels in the downstream stretches of the Chao Phraya are expected to rise by between 40 and 60 centimetres, he said.
In Pathum Thani, the flooding situation in the province's Rangsit Municipality went from bad to worse on Tuesday as the water levels in Khlong Rangsit Prayunsak, the main canal in the municipality, rose to a critical point and prompted a warning for residents in low-lying communities to begin moving their belonging to higher ground.
Praphit Chanma, director-general of the RID, meanwhile, dismissed accusations made on social media that mismanagement had caused flooding in Pathum Thani.
He insisted it was the torrential rain, more than 300 millimetres in some areas downstream including Pathum Thani itself, that mainly caused the floods.
However, one key canal faced with a critical water level is Khlong Prawet Buri Rom in eastern Bangkok, which has already caused floods in Lat Krabang district, said Bangkok governor Chadchart Sittipunt.
The governor also warned that high levels in certain parts of Chachoengsao, normally a water catchment area for the city, are impeding drainage efforts in Lat Krabang.