AN UNUSUAL and rapid fluctuation in water levels of the Mekong River during the past three months has raised deep concern among local people over its impact on agricultural activities, fisheries and transport along the river.
The Water Resources Department is seeking help from the Mekong River Commission (MRC) to provide more information about the mysterious rise and fall in levels of the longest river in Southeast Asia.
The unusual phenomenon has been recorded since last year when the water level in the Mekong in the northern province of Chiang Rai’s Chiang Saen district rose rapidly from 2.73 meters on December 6 to 6.75 meters on December 17.
Another unusual event was detected earlier this month when the water level drastically dropped to 1.6 meters, nearly the level of the dry season. Many sandbars have appeared along the river.
“Local villagers cannot grow vegetable farms beside the river, and boats cannot sail along it,” said Jeerasak Inthayot, a coordinator of Rak Chiang Kong Network.
Agricultural farms along the riverbanks, fisheries and sailboat services have been affected by the rising and falling water levels. Most people living along the river in Chiang Saen grow plants alongside the riverbank to make money, and they catch fish to eat and sell at the market. Some also provide commercial sailboat services.
Since water levels in the Mekong have begun to fluctuate over the past several months, Jeerasak – who has been working with local people to monitor these changes – said villagers suspected China-based dams were the major cause behind the unusual change in levels.
“Local people think that the water level is controlled by the dams in the Mekong River’s upper stream in China,” he said.
Since 1996, China has installed at least three dams along the Mekong River’s upper stream. Currently, three dams are under construction and another two are proposed for the future.
Water Resources Department’s deputy director-general Chaiporn Siripornpibul said the water level in the Mekong in the post-dam period is higher than during the pre-dam periods, especially in the dry season.
The Mekong River Commission (MRC) is the intergovernmental body responsible for cooperation on the sustainable management of the Mekong Basin. Its members include Cambodia, Laos, Thailand and Vietnam.
Siripompibul told the MRC that unusually high rainfall in mid-December 2013 was the most likely cause of the drastic increase in river levels.
He explained that the amount of rainfall was registered at 120 millimetres per day during December 15-17.
He insisted that the rapid rising water levels in the river during this period were not caused by discharge from the dams in China.
However, his agency is now investigating another event, the unusual decrease in water levels first noticed earlier this month.
A local newspaper reported that Nong Khai Marine Office director Suriya Kittimonthon had issued a warning last February 3 that China would stop discharging water into the Mekong River for 15 days as it was repairing the dams. As a result, the water level in the Mekong would drop during this period.
Additionally, Suriya said the rapid rise of water levels in the Mekong River during December 17-20 was caused by the discharge of dams in China as it prepared to maintain them.
Chaiporn said he was now sending a letter to the MRC to get clear answers behind the unusual fluctuation of the Mekong’s water levels.
Previously, China had promised to send water-level and related data to Thai authorities following the meeting of the MRC at Prachuap Khiri Khan’s Hun Hin district in 2010, but the only available data was from the rainy season.
“We are trying to negotiate with Chinese authorities to provide more information related to water levels in the dry season as well,” he said.
The Water Resources Department is also conducting a survey to study the physical condition of the Mekong River – including the incubation of fresh-water fish, the erosion of the riverbank, and the water quality along the river.
“This information will not only help us to learn about changes in the Mekong River, but we will also use these details to ask for compensation from those who cause damage to this great river,” he said.