Massive runoff from the North which is likely to hit Sukhothai tomorrow has forced officials into taking emergency steps to protect the province's city centre by keeping the water level of the Yom River low and using ponds to retain the deluge.
The measures were announced Monday by Royal Irrigation Department chief Thongplew Kongjun as Sukhothai governor Phiphat Ekkaphaphan ordered officials to monitor the situation around the clock and brace for possible flash floods this week.
A similar order was earlier issued in Kanchanaburi, a western province that is bearing the impact of tropical storm Bebinca, which has now weakened and become a low-pressure system.
Last week, the storm triggered heavy downpours in upper Thailand, rapidly generating huge amounts of runoff in the Yom River which runs through Phrae and Sukhothai, two provinces in the North.
Its flow rate in Phrae's Muang district was expected to reach a maximum point at 900 cubic metres a second Monday. With this speed, "the river will pass Sukhothai's Sri Satchanalai district at 850 cu m/second on Aug 22", Mr Thongplew said.
The district, located north of the province, is the first area to be hit by the runoff.
One measure to deal with the powerful deluge is to reduce the water level in a section of the Yom River which runs downstream to Hat Saphan Chan floodgate in Sawankhalok district, the department chief said.
Part of the runoff will be retained in front of the floodgate and more will be diverted to the Yom-Nan canal, which will carry water to the Nan River and Bang Kaeo canal, also known as "Old Yom River".
Other parts of the runoff will be diverted into the province's four water-retention ponds, Mr Thongplew said.
Officials are currently discharging water from Thung Thale Luang to make room for it to hold up to 25 million cu/m of water.
Another three ponds -- Bueng Khiraeng, Bueng Takhreng and Bueng Raman -- will altogether be able to retain 16 million cu/m.
"A goal is to keep the river flow rate in Sukhothai's Muang district at 550 million cu/m per second," Mr Thongplew said.
"This will protect economic areas and communities in the city centre against flooding."
Officials in Phitsanulok are also preparing to deal with the runoff as it flows from Sukhothai's Muang district to the flood-prone Bang Rakam in Phitsanulok along the course of the Yom River.
Officials are currently attempting to reduce the water level of a section of the river near Khlong Bang Kaeo floodgate in Bang Rakam to make it able to hold more water.
Flood protection must be reinforced in low-lying areas in Bang Rakam, Phrom Phiram and parts of Muang districts, Chamnan Chuthiang, chief of Yom-Nan river conservation and irrigation in Phitsanulok, warned.
Bang Rakam is a major concern because a section of the Yom River in this district is "narrow and only able to deal with water at a rate of 330 cu m/second", he said.
Officials plan to address the runoff by diverting the water into a riverside paddy field. Such an action can be carried out immediately as farmers have already harvested their crops, Mr Chamnan said.
Elsewhere, officials are coping with damage and losses left by Bebinca as well as bracing for the next round of floods.
In Chiang Rai's Mae Chan district, overflow from Muang Phra Khru creek severely damaged and cut a local road leading to San Mong Khon village while a resident in Wiang Pa Pao district was found dead after being washed away in a flood.
In the Northeast, the water level in the Mekong River is becoming critical, leaving officials in Nakhon Phanom gravely concerned about new flash floods.
So far officials have struggled to speed up flow rates in the Un, Songkhram and Kam rivers which run into the Mekong.
- Earlier report: Floodwaters rise in North, Northeast