Twenty-six of the 77 Thai provinces have been hit by floods this rainy season, affecting 2.6 million people.
On Wednesday, 400 families were forced to evacuate Bang Phrahan district in Ayutthaya province, 90km north of Bangkok, as the Chao Phraya River overflowed its banks.
Officials have been forced to release water from the two largest dams, Bhumibol and Sirikit, into the Ping and Nan rivers, which feed into the Chao Phraya.
"The problem is water management," said Smith Dharmasaroja, head of the Natural Disaster Warning Foundation.
"We kept too much water in the dams early in the rainy season, and now at the end of the season, they have to release a large amount of water at the same time, which has caused floods."
Thailand's rainy season usually starts in May and ends in October.
Smith blamed the rains on a lengthy La Nina cycle, a weather phenomenon marked by heavy precipitation that typically follows an El Nino period of drought.
"This La Nina started early and was supposed to