The volume of usable water in Khon Kaen's Ubolratana Dam has dropped by 11% due to the insufficient number of wastewater treatment plants that could process runoff discharged by the agriculture and industrial sectors in the region, according to the Office of National Water Resources (ONWR).
Surasri Kidtimonton, ONWR secretary-general, said officials are still working on the inundation and drought mitigation plan for the Chi River basin area, which covers about 12.85 million rai of land in Kalasin, Khon Kaen, Maha Sarakham, Mukdahan, Yasothon, Roi Et and Udon Thani.
From May 1 to Oct 31, the dam will release water downstream to help maintain water supplies for five Provincial Waterworks Authority offices that cover 45 villages. The release will also support 10 industrial sites along the Pong River.
Mr Surasri said the Ubolratana Dam, the largest irrigation reservoir in the Northeast, currently holds about 789 million cubic metres (m³) of water -- or 32% of its total capacity of 2.43 billion m³ -- of which only 207 million m³ is usable water. This is about 11% lower than last year's 220 million m³, he said.
The ONWR said many areas in the central Chi River basin regularly face water-related problems, such as floods during the rainy season, water shortages in the dry season and water quality issues.
"The ONWR have learned that the area's low water reserves are mainly caused by the insufficient number of water treatment plants to process discharges from farms and factories, as well as runoffs from the North," he said.
A check on the Chi River basin showed the water volume of Chulabhorn Dam in Chaiyaphum remains at 61.5 million m³, only 39% of which is usable, while the Lam Pao Dam in Kalasin remains at 768 million m³, 87% of which is usable.
Those areas regularly face inundation, intermittent rain and water-related environmental issues each year, particularly drought that has affected about 7.47 million rai of land.
Overall, the area's dams and reservoirs can hold about 2.47 billion m³ of water, but the region requires at least 3.37 billion m³ of water consumption to support daily activities including farming, industry and tourism, according to the ONWR's latest estimate cited by Mr Surasri.
He also said the Thai Meteorological Department estimated the amount of rainfall may be lower than average this year due to El Nino.
State agencies will come up with a new water management plan for next year, he added.
