The spillway gates at Vajiralongkorn dam in Kanchanaburi's Thong Pha Phum district were opened for the first time in 16 years yesterday to maintain the reservoir at a manageable level.
Waiwit Saengpanit, director of the dam, opened the two gates yesterday morning, increasing the discharge rate from 43 million cubic metres to 53 million cu/m a day.
He said the gates will be kept open for five days. Increasing the discharge rate by 10 million cu/m a day would raise the level of the Kwai Noi River only slightly.
Yesterday, the dam, also known as the Khao Laem dam, held 8.03 billion cu/m of water, which is 91% of its manageable capacity. The level was 2.49 metres above its upper rule curve.
In the previous 24 hours, inflow to the dam has totalled 50.1 million cu/m.
The first area to be affected by the opening of the gates was Chalerm Phrakiat Rama IX public park, about 5 kilometres downstream on the Kwai Noi River. The river level has been 30cm above its banks over the past 10 days and is expected to rise by another metre.
Local hoteliers along the river have already moved their belongings to higher ground meaning the rising water level would not affect local communities, Mr Waiwit said.
In nearby Phetchaburi province, residents of Muang municipality are also facing rising floodwaters, which has spread to various roads and swamped the historic site of Wat Yai Suwannaram.
The Phetchaburi River burst its banks and flooded several low-lying areas of the municipality on Wednesday and the inundation became more critical yesterday.
The river overflow continues to ravage several roads as the floodwater keeps rising.
Officers have mobilised to pump water out of the downtown area.
Floodwater in central Phetchaburi was 10-40 centimetres deep as of yesterday morning. Local officials tried to contain the flooding using pumps and sandbags.
The floodwater also submerged Wat Yai Suwannaram, the province's key historic site situated at the heart of the municipality. However, Phetkasem Road, the key route to the South, remains unaffected.
Samroeng Saengphuwong, deputy secretary-general of the Office of the National Water Resources, said the Kaeng Krachan dam in Phetchaburi held 767 million cubic metres of water yesterday or 108% of its capacity. This figure was 6 million cubic metres below the amount on Wednesday.
In Chiang Rai, forest runoff has submerged houses and farmland in several tambons of Chiang Khong and Chiang Saen districts following torrential rains.
Chiang Khong district chief Thassanai Suthapoj yesterday surveyed the flooded locations and provided relief assistance for the affected residents. Highway 1020 in the district was inundated and officers deployed barriers preventing motorists from heading to the flooded section.
Mr Thassanai said various villages in tambons Sathan and Sri Don Chai of Chiang Khong district were submerged in the wake of forest runoff.
In the southern province of Phangnga, runoff from Dok Daeng mountain swamped houses and damaged a bridge which is under construction in tambon Bang Sai of Takua Pa district, making it impassable for any kinds of vehicles.
