He explained that during the rainy season, runoffs from Ping, Wang, Yom and Nan rivers in the North accumulate in the Chao Phraya, causing the water level to rise.
The water level of the Chao Phraya is mainly controlled by the Chao Phraya dam in Chai Nat province. If the level of the dam is high, its drainage rate will rise.
Pa Sak and Lop Buri rivers join the Chao Phraya in Ayutthaya province, with Rama VI dam controlling the water level.
Over the past week, both the Chao Phraya and Rama VI dams have been discharging water at a higher rate, which has increased the water level of the river running through the capital. This increase in water level has Bangkokians worried the city will get inundated like it did in 2011.
Aswin explained that the 2011 floods were caused by continuously heavy rain brought by several storms, which pushed the water level in the Chao Phraya much higher than it is now.
He also said that water discharged from the two dams in 2011 was 4,000 and 3,860 cubic metres per second, compared to 2,775 and 2,875 cubic metres per second this year.
He added that the Bangkok Metropolitan Administration (BMA) has put up barricades and prepared water pumps for drainage. There is also a water-level monitoring station working 24 hours a day.
The BMA has said it will immediately notify Bangkokians who may be at risk.