BANGKOK, THAILAND – Thai authorities confirmed a significant reduction in the Chao Phraya Dam’s discharge rate this week, aiming to lower river levels across central provinces as rainfall declines in the north.
As of 17 November 2025, the Office of the National Water Resources (ONWR) ordered the flow through the Chao Phraya Dam in Chai Nat province to be reduced from 2,800 cubic metres per second to between 2,400 and 2,700 cubic metres per second. Officials forecast a water-level drop of 40 to 75 centimetres between 20 and 24 November.
Lower rainfall triggers flow adjustments
Paitoon Kengkanchang, Deputy Secretary-General of the ONWR, explained the reason behind the adjustment was the decrease in rainfall affecting northern catchment areas.
“We are reducing the discharge rate from about 2,800 cubic metres per second to 2,400–2,700 cubic metres,”
said Paitoon Kengkanchang, Deputy Secretary-General of the Office of the National Water Resources.
Authorities in Tak province lowered daily water releases from the Bhumibol Dam from 50 million to 45 million cubic metres on Sunday and Monday respectively. This move directly influenced the Ping River, which flows through Tak, Kamphaeng Phet and Nakhon Sawan provinces, where officials expected level drops of 10–15 centimetres.
Impact on central Thailand
By the weekend, the Chao Phraya Dam‘s discharge had already decreased from 2,880 to 2,800 cubic metres per second, according to the ONWR. The Royal Irrigation Department (RID) confirmed that water diversion into farmland along both riverbanks continued concurrently. The RID stated that flow would be further reduced to the planned range between 20 and 24 November, likely leading to visibly lower levels south of the dam.
Flood situation remains serious in 13 provinces
Despite easing conditions in many districts, the Department of Disaster Prevention and Mitigation (DDPM) reported ongoing flooding in 13 provinces as of Sunday. Officials noted mixed trends in water movement:
- Uthai Thani: declining levels in Muang District
- Chai Nat: stable conditions in Wat Sing, Manorom, Muang, Sapphaya, and Sankhaburi
- Sing Buri: steady levels in In Buri, Phrom Buri, Muang
- Ang Thong: falling levels in Pa Mok, Wiset Chai Chan, Chai Yo, Muang
- Suphan Buri: stable in Muang, Bang Pla Ma, Song Phi Nong, U Thong
- Ayutthaya: stable in Sena, Bang Pa-In, Phra Nakhon Si Ayutthaya
- Pathum Thani, Nonthaburi, Nakhon Pathom: mostly steady water levels
- Phitsanulok: rising in Bang Rakam
- Nakhon Sawan: steady in Chum Saeng, Muang, Phayuha Khiri, Krok Phra
- Sukhothai: decreasing in Sawankhalok, Muang
- Ubon Ratchathani: receding in Muang, Warin Chamrap, Phibun Mangsahan
Outlook for the coming days
Experts from the ONWR said the gradual reduction of dam discharge would continue stabilising the central plains if dry weather persisted in northern Thailand. The agency coordinated closely with the Royal Irrigation Department to manage the next phase of regulation.
“Our goal is to maintain the balance between flood control and the water needs of agriculture,”
said Paitoon Kengkanchang, Deputy Secretary-General of the Office of the National Water Resources.
Key points released by the ONWR included:
- River levels may drop up to 75 cm south of the Chao Phraya Dam
- 13 provinces remain affected by flooding
- Gradual relief expected but no full all-clear yet