To Royol Chitdon, director of the Hydro and Agro Infomatics Institute, continued downpours over Bangkok are clearly more of a threat than the run-off.
"Bangkok residents should be worried about rainfall rather than the run-off water," he said. Royol sits on a sub-panel of the Water and Flood Management Commission (WFMC).
The Meteorological Department forecast rain and downpours for many areas of the country, including the Central region, from yesterday through next Tuesday.
Bangkok Governor MR Sukhumbhand Paribatra said separately that the capital's drainage system was capable of dealing with heavy downpours and river overflow.
Sukhumbhand said the city administration would not object to a plan by WFMC chairman Plodprasob Surassawadee, who is also the science minister, to direct a certain amount of water to the sea via Bangkok.
"But please don't use Bangkok as a floodway. The available system can't deal with run-off water," he said.
So far, the overflowing Chao Phraya River has flooded several areas of Angthong province, which have been declared disaster zones.
Hundreds of families living along the main river in the province's Pa Moke, Wiset Chai Chan, Muang Angthong, Chaiyo and Pho Thong districts are struggling with inundation.
"The Chao Phraya Dam in Chai Nat has released more water into the river," Angthong's disaster prevention and mitigation chief, Chatnarong Siriporn na Ratchasima, said yesterday.
First Army Region chief Lt-General Udomdej Sitabutr, meanwhile, inspected the flood situation in Pa Moke district.
The armed forces, according to Defence Minister Sukampol Suwannathat, have been working closely with the government on flood-prevention and flood-relief operations.
"The leaking embankment in Sukhothai has already been fixed," he said. "We are making necessary preparations for Bangkok too."
Although Sukampol did not name specific areas, he hinted that some areas such as industrial estates would be fiercely protected while some flood-prone areas would be inundated. He said it would not be possible to keep some low-lying areas dry as they had flooded during certain periods of every year for decades anyway.
Niwatchai Khamphee, deputy director-general of the Water Resources Department, said work on the three-year Yom-Nan River Basin Development Plan was just 20 per cent complete.
"Work done to date may not be able to prevent provinces in the basins from flooding during the wet season this year," he said.
Located in the Yom River Basin are Phrae, Sukhothai, Uttaradit and Phitsanulok provinces. Farmlands in these provinces often flood during the wet season and suffer from drought during the dry season.