About 100 cubic metres a second of water from the Noi River, a branch of the Chao Phraya, is being diverted through three sluice gates to a paddy field area in Phak Hai district to relieve flooding in communities alongside the Noi River, said Natthi Bosuwan, an assistant to Ayutthaya's governor.
The water retention area is a flood prevention measure of the Royal Irrigation Department to cope with the northern run-off that flows downstream of the Chao Phraya. The water will be contained in the vast tract of farmland to lessen inundation in low-lying areas.
The water diversion will not affect farmers as they have already harvested their crops, Mr Natthi said.
The officials are monitoring "massive run-off" that has left flooded Sukhothai for Phitsanulok and will then flow south towards the Chao Phraya barrage in Chai Nat, he said.
They will later decide whether to divert part of the run-off to the paddies in Bang Ban field, located to the west of the Chao Phraya, when it arrives in Ayutthaya.
Water levels in the Noi, Chao Phraya and Pasak rivers yesterday increased by 5-20cm and will rise further over the next two days following the release of more water from the Chao Phraya barrage, the Office of Regional Irrigation 12 said.
About 3,000 households near the Noi River in Sena district have been flooded, causing authorities to declare disaster zones in eight tambons.
Learning of the flood situation in Ayuthaya, His Majesty the King has provided 2,000 survival kits for distribution to people in Sena and Bang Ban districts.
Many people in the neighbouring province of Ang Thong are also affected.
Flash floods in the Central Plains yesterday forced residents in tambon Champa Lo of Muang district to dismantle their homes located by the Chao Phraya and relocate elsewhere for fear it will be collapsed into the river.
Earlier, a 200m section of the riverbank was destroyed by the rising water level.
As more run-off could flow downwards to Sing Buri, Ang Thong and Ayutthaya, Sakdiphong Thamachawakun, assistant to tambon Bang Nga's mayor in Lop Buri, has called on the government to divert more water to the Ta Chin River because a section of the Chao Phraya in the three provinces is "too narrow and shallow" to receive a large amount of water.
Prime Minister Yingluck Shinawatra sought to calm people in tambon Sa Pho Thong and Non Kok in Chaiyaphum's Kaset Sombun district, where a torrent from the Phu Laen Kha mountain range has caused widespread flooding of crop fields and local roads.
In Tak province, strong overflow from the Wang River has broken through a road levee and put Ban Yang Ong Nam as deep as 1.5m under water. About 400 homes have been flooded.