Eleven major dams are reaching the limit of their storage capacities, which is putting them at risk of flooding, according to the Royal Irrigation Department (RID).
Most are reservoirs and hydro-dams located in the northeastern and western parts of the country.
The Vajiralongkorn, Kaeng Krachan and Pran Buri dams in the West are said to be facing problems, as are the Nam Oon, Nam Phoong, Chulabhorn, Ubonrat, Lam Pao and Lam Phra Plerng dams in the Northeast.
Mae Ngad Somboonchon reservoir in Chiang Mai and the Pasak Jolasid dam in Lop Buri are also considered at risk.
To cope with these problems, the government has ordered the reservoirs and dams to be drained at a faster rate so they can receive more rainfall that is expected to pound the northeastern and western regions of the country until Saturday.
Eroded by rain: Workers and engineers repair a road leading to the peak of Phu Thap Boek, a 1,768-metre tourist destination in Phetchabun, after deep cracks appeared in the wake of a landslide. The authorities are finding ways to stop wider areas from being affected. (Photo by Sunthorn Kongwarakom)
The state-run Electricity Generating Authority of Thailand (Egat) was ordered to release 38 million cubic metres a day from the Vajiralongkorn dam in Kanchanaburi province, up from 28 million cu/m now.
The agency has already increased the amount of water discharged from the Srinakarin dam in the same province from 8 million cu/m per day to 13 million cu/m.
The westernmost district of Sangkhla Buri is suffering serious flooding due to heavy rains that have led to run-off in valley areas.
The RID insisted Wednesday that increased discharge would not affect areas downstream.
Somkiat Prajamwong, secretary-general to the Office of National Water Resources, said the government would impose two measures for better water management in reservoirs.
The first is a cap on capacity and the second is the building of sluice gates.
"We need to accept that not all reservoirs and dams can manage their water flow well due to certain limitations," Mr Somkiat said.
"But due to the current crisis associated with climate change, dams and reservoirs must be changed from only generating electricity, or being used for farming purposes, to become part of the flood-control system."
He said limits would be placed on how much water they can store from next year, with 10% of their total capacity left empty to account for water-drainage.
Some non-hydro dams and medium-or small-sized reservoirs are not equipped with sluice gates which has limited their capacity to discharge floodwater in such situations, he added.
- Earlier report: Vajiralongkorn Dam brimming over