Prime Minister Prayut Chan-o-cha has warned farmers to brace for the impact from reduced dam water releases.
The government has ordered provincial governors to work with the military and police to stop farmers from diverting water for their farmland, following its move to cut dam water releases to reserve water for consumption.
"Water for the farming sector will be in short supply. Be warned that water discharges [from dams] must be reduced or it may not be released at all," the prime minister said Tuesday.
"Otherwise, we cannot survive until August when rainfall is forecast to arrive."
The government must prioritise reserving water for wider public consumption, Gen Prayut said, adding that enough water must also be kept aside to push away salt water from the sea creeping into rivers.
Interior Minister Anupong Paojinda said the cabinet decided that water discharges from four major dams in the Chao Phraya River basin will be cut from 28 million cubic metres per day to 18 million cu/m.
This followed a proposal submitted by the Royal Irrigation Department, as it is expected there will be no rain until the middle of next month, he said.
The reduction in dam water releases will begin tomorrow, Gen Anupong said.
"This is a critical period and the prime minister has prepared measures to help farmers who will be affected by the reduction in water discharge," Gen Anupong said.
However, a government source said, the cabinet had not considered the Finance Ministry's proposal for 60 billion baht to be put aside to help affected farmers.
Gen Prayut wants authorities to examine the exact number of affected farmers and the level of impact before the government makes any decision on a budget, said the source.
Meanwhile, the drought crisis in Thailand could worsen and drag on to next year if there is no rainfall in the North and Northeast regions by September, Meteorological Department (TMD) director-general Wanchai Sakudomchai said, also on Tuesday.
"If the rain doesn't come by September, we will be in dire straits," Mr Wanchai told the Bangkok Post.
Despite recent rainfall in Bangkok and other parts of the country, not enough had fallen into the rivers and major dams that supply water to farmers in the central regions and drinking water to Bangkok residents, he said.
Thailand had been hit by the El Nino dry weather pattern since last year, but the amount of rainwater in the past year was more than during the 1997 El Nino crisis, thanks to some rain in January and February, Mr Wanchai said.
TMD forecasts suggest that tropical storms will arrive in the Central region in August, which should replenish the water supply in the Bhumibol and Sirikit dams.
"If they don't come, we will be in big trouble," Mr Wanchai said.
The El Nino weather pattern that can cause droughts in Asia and heavy rain in the Americas will probably last into next year.
This is longer than previously expected and could potentially upset crops and commodity prices.
Lalit Thanomsingh, assistant secretary to the Chaipattana Foundation, said His Majesty the King has allowed the Rama IX reservoir, which is under the care of the royal foundation, to be used to ease people's suffering during the dry season every year.
Mr Lalit said the Provincial Waterworks Authority had asked the foundation for water from the reservoir to be used in tap water production, to help people affected by water shortages in Pathum Thani.
He added that Her Royal Highness Princess Maha Chakri Sirindhorn, the foundation's chairwoman, said people affected by water shortages must be helped.
This was despite low water levels in the reservoir, and there was a risk that diverting water from the reservoir could lead to a nearby road collapsing.
"It is alright if the road could be damaged, but the water must be used to help people first," Mr Lalit quoted the princess as saying.
Agriculture and Cooperatives Pitipong Phuengboon Na Ayudhaya said the amount of rainfall this year has dropped by 50% compared to the previous year.
He stressed there must also be enough water reserved to prevent sea water inflows from contaminating the Chao Phraya River. Allowing the river to become too salty will harm tap water production for consumption, he said.
