ONWR updates flood-risk provinces as Chao Phraya discharge rises
ONWR warns residents in riverside areas in six provinces to monitor rising water after Chao Phraya Dam discharge increased to 2,200 cubic metres per second.
- The Office of the National Water Resources (ONWR) has issued an updated flood warning as water discharge from the Chao Phraya Dam increases.
- Six provinces downstream from the dam have been identified as being at risk and are urged to monitor the situation closely.
- The dam is releasing water at 2,200 cubic metres per second, which is expected to raise downstream river levels by 20 to 30 centimetres.
- The affected provinces are Chai Nat, Sing Buri, Ang Thong, Phra Nakhon Si Ayutthaya, Pathum Thani, and Nonthaburi.
The Office of the National Water Resources (ONWR) has updated the nationwide water situation, identifying areas in six provinces that should remain on alert as discharge from Chao Phraya Dam increases.
The assessment, issued at 7am on Wednesday (September 30), showed that the highest rainfall totals by region were recorded in Surat Thani in the South at 88 millimetres, Lamphun in the North at 84mm, Ratchaburi in the West at 60mm, Saraburi in the Central region at 42mm, Chachoengsao in the East at 37mm and Ubon Ratchathani in the Northeast at 34mm.
Rainfall across upper Thailand is expected to decrease on Wednesday, although isolated thunderstorms remain possible. Parts of the South could still experience heavy rain as the southwest monsoon over the Andaman Sea, Thailand and the Gulf of Thailand weakens, while southerly and southeasterly winds prevail over the lower Gulf.
From October 1–3, upper Thailand is forecast to receive less rain, although thunderstorms could continue in some areas. A moderate southwest monsoon will prevail over the North, Central region and South, while southeasterly winds will cover the Northeast and East.
Reservoirs nationwide currently hold 63.718 billion cubic metres of water, equivalent to 79% of total storage capacity. Usable water stands at 39.596 billion cubic metres, or 70%.
Regional reservoir storage:
- North: 19.825 billion cubic metres, or 72%
- Northeast: 8.118 billion cubic metres, or 67%
- Central region: 1.375 billion cubic metres, or 73%
- East: 2.889 billion cubic metres, or 91%
- West: 26.179 billion cubic metres, or 92%
- South: 5.332 billion cubic metres, or 70%
Chao Phraya levels continue to rise
In the Chao Phraya basin, data recorded at 6am on September 30 showed rising water levels at two monitoring stations in Nakhon Sawan.
At station P.17 in Banphot Phisai district, the water level stood at 37.94 metres above mean sea level, 0.31 metres below bank level, and was rising. At station N.67 in Chum Saeng district, the level was 26.24 metres above mean sea level, 1.97 metres below bank level, and was also rising.
At station C.2 in Mueang Nakhon Sawan district, water was flowing at 2,326 cubic metres per second, while the level stood at 23.51 metres above mean sea level, 2.19 metres below bank level.
Chao Phraya Dam was releasing water at 2,200 cubic metres per second. Water levels stood at 17.69 metres above mean sea level upstream of the dam and 15.22 metres downstream.
Six provinces urged to monitor rising water
ONWR has issued a warning over the impact of the increased discharge from Chao Phraya Dam, noting that a flow rate of 2,200 cubic metres per second is expected to raise downstream water levels by about 0.20–0.30 metres from current levels.
Areas requiring close monitoring:
- Chai Nat: Sapphaya district
- Sing Buri: Phrom Buri, Mueang Sing Buri and In Buri districts
- Ang Thong: Mueang Ang Thong, Wiset Chai Chan, Chaiyo and Pa Mok districts
- Phra Nakhon Si Ayutthaya: Bang Saai, Sena, Phak Hai, Bang Ban, Phra Nakhon Si Ayutthaya, Bang Pa-in, Bang Sai and Lat Bua Luang districts
- Pathum Thani: Sam Khok and Mueang Pathum Thani districts
- Nonthaburi: Mueang Nonthaburi, Bang Kruai and Pak Kret districts
