Maitree Pitinanont, director of irrigation projects in Ayutthaya, alerted all agencies in the central province on Saturday to prepare for increasing water levels, especially in Tha Rua, Nakhon Luang and Phra Nakhon Si Ayutthaya districts.
The Phra Ram VI is currently discharging 350 cubic metres of water per second but the volume will increase to 500 cu m/second on Sunday as it has been unable to absorb rising water from the Pasak Jolasit Dam in Lop Buri, Mr Maitree said.
As a result, the water level of the Pasak River on Sunday would rise by one to 1.5 metres more, he added.
Many areas in Ayutthaya including Sena, Phak Hai and Bang Ban districts have been flooded due to the rising water level of the Chao Phraya River, relief officials said.
In Prachin Buri, meanwhile, workers at the 304 Industrial Park were fighting flooding that continued to hit Sri Maha Phot and other districts in the province.
Poolsak Sutanthavibul, executive vice-president of the industrial estate, said on Saturday that all factories remained operational as the park was draining water from the compound.
The park was expected to be a target as water from Kabin Buri district was moving toward Sri Maha Phot and other locations including the business centre in Muang district.
Road 3079 which passes the estate was under water for two kilometres after rain hit the area on Friday night.
Sri Maha Phot has been hit by flooding on Saturday. (Video by Thanarak Khoonton)
As the water showed no signs of subsiding, about 200 villagers continued to protest for the second day on Saturday ,urging authorities to open a sluice gate to drain the water out to other areas.
Kanisorn Chopanya, chief of the Disaster Prevention and Mitigation office in Prachin Buri, said the water level in Kabin Buri municipality was decreasing from up to three metres in some areas on Saturday. The water was flowing toward Sri Maha Phot, Prachantakham and Muang districts, he warned.
Kabin Buri was inundated mainly by water from Khao Yai National Park and overflows from the Prachin Buri River.
The water began to overflow some riverside roads in Muang district, causing water up to 30 centimetres high amid concern that it would enter the town centre.
Prachin Buri is one of 27 provinces still affected by floods, the Disaster Prevention and Mitigation Department in Bangkok said on Saturday. The flood has already killed 19 people.
Pathum Thani governor Siripong Hantrakul told Prime Minister Yingluck Shinawatra that the province could handle the overflowing water from Chao Phraya. The situation was better than during the great floods two years ago, he added.
The Meteorological Department on Saturday issued a warning for people in 10 provinces in the Central Plains and the East to brace for heavy rain triggered by a monsoon trough over the next few days.
People living near hillsides and waterways in Nakhon Sawan, Uthai Thani, Lop Buri, Saraburi, Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chanthaburi and Trat should prepare for heavy rain and possible landslides during this period, it warned.
The department also warned of more rain and isolated heavy rain in the Northeast on Tuesday, as tropical storm Wutip in the upper South China Sea will make landfall in upper Vietnam on that day.