The Chimplee, Taling Chan and Bang Lamat subdistricts of Taling Chan were declared "surveillance areas" yesterday after the Chao Phraya River reached a record high of 2.53 metres and some parts of the floodwall leaked.
"Evacuations may be ordered," Governor Sukhumbhand Paribatra said.
The permanent embankment stretching along most of the Chao Phraya in the capital stands just 2.5 metres high. The overflow reached Samsen Sois 21 and 23 and many more zones.
Besides the spillover from the swollen river, the capital has also been swamped by runoff from upstream provinces in several districts, including Sai Mai and Thawee Watthana.
On Saturday night, the Bangkok Metropolitan Administration (BMA) told Bangkok residents along the Lat Phrao, Bang Khen, Thanon, Bang Bua and Prem Prachakorn canals in Don Muang district to prepare to move to evacuation centres.
Already 10,343 flood victims are staying at BMA-run evacuation centres. Recently 10 were closed because floodwaters rose to a dangerous level. These 10 centres are schools in Thawee Watthana, Sai Mai, Khlong Sam Wa and Don Muang districts.
Sukhumbhand said almost all of Don Muang was now submerged.
"We're trying to solve the problem," he said.
The main problem was that there was nothing to block the water flowing down Paholyothin Road from the Rangsit Prayoonsak Canal.
"The BMA has already informed the Flood Relief Operations Centre about this many times," Sukhumbhand said in a thinly veiled attack on the body established by the central government.
Weera Wongsaengnak, chief of Water Management in the Disaster Zone, still saw a light at the end of the tunnel.
The inner city would remain under a serious threat of flooding only for three more days.
"The high tides peaked today and will continue to drop. If we can control the situation till Tuesday, Bangkok will be saved. After that, we just need to prevent the embankment and dykes from crumbling down," he said.
"There is no longer any big bulge of water. There is only the water that has already arrived. The water that has caused Thammasat and Rangsit to be flooded comes from the Prem Prachakorn Canal overflowing to the Chulalongkorn sluice gate. When there is sea intrusion, the water rises but only for three hours,'' he said.
The water on Asia Road and in Canals 1 and 9 was no longer rising.
However, authorities could assess the flood situation in Bangkok only after tomorrow.
The floodwaters in Don Muang and Sai Mai would be drained out on Friday or the following Tuesday when the tide would be at its lowest. The tide will peak again from November 12-13 but then there will be no monstrous mass of water meandering down from the north, he added.
Still, it remains to be seen how long the floodwall can stave off the massive runoff. Cracks have been reported almost daily.
The latest appeared on some spots of the embankment along the Phra Khanong Canal, flooding Phra Khanong district.
"We are trying to fix it," said Wiparat Chaiyanukij, director of the Khlong Toei District Office.
Prime Minister Yingluck Shinawatra called a meeting of agencies and ministers to discuss changes to the flood rehabilitation plan.
Yingluck posted a message on Facebook saying Chinese Prime Minister Wen Jiabao phoned her to express his condolences to the Thai people and his confidence that the Thai government can overcome the disaster and enact a speedy rehabilitation.