In its editorial on March 3, The Nation urges Mekong River countries meeting this week to enlist Beijing's full cooperation in managing the water flow.
Rather than doing the expected and simply hailing China's generosity in helping relieve severe drought in our region, Prime Minister Prayut Chan-o-cha needs to do his homework ahead of the Mekong Cooperation Summit in Hainan this week.
Otherwise a crucial opportunity to take a stand on Thailand's best interests could vanish in favour of a mere hand-shaking exercise and photo opportunity.
The northerly reaches of the 4,900-kilometre-long Mekong River flow through China, which has built six dams, impeding the flow of water to countries downstream and having a serious impact on lives and livelihoods.
China's decision to discharge additional water from one of these dams between March 15 and April 10 seems to have come in response to a request from Vietnam, where the flow-depleted Mekong Delta is being damaged by saltwater entering from the South China Sea.
According to Vietnam's embassy in Beijing, Chinese authorities on water resources met with its staff on March 14 to convey their decision.
The Vietnamese were told that, starting the next day and continuing until April 10, China would increase the discharge of water from its Jinghong Dam from 1,100 cubic metres per second to 2,190 cubic metres.
The Chinese said they were responding to the severe drought gripping Laos, Thailand and Cambodia and the problem afflicting Vietnam.
Vietnam greeted the announcement with grateful praise, as did the Thai government, but citizens of South-east Asia who actually live along the Mekong were immediately alarmed by the potential for calamity in the rapid change in water level.
The abrupt fluctuation in such a short period was bound to cause trouble for people who rely on fishing and tourism, as well as those growing vegetables along the banks, they warned.
And indeed, water has inundated the south shore of the river in Loei province and elsewhere, confounding residents who earn a living from dry-season tourism.
Given that Beijing had never before informed the downstream countries of its plans regarding water-resource management, the letters sent this month to all four member-countries of the Mekong River Commission were most welcome, as was the effort to help in time of crisis.
The extremely short notice, however, resulted in problems that had perhaps not been foreseen.
China and Myanmar are dialogue partners to the Mekong Commission, which has Thailand, Laos, Cambodia and Vietnam as its members.
As the sole international body handing planning and issues that arise along the river, it has made several attempts to recruit China as a full member so that there are no gaps in the regulation of activities.
Now the leaders of all six riparian states are preparing to meet in Sanya on the resort island of Hainan off China's southern coast.
It's their first "summit", although the delegations are familiar with one another from meetings of the Greater Mekong Sub-region and the Lancang-Mekong Cooperation, on which foreign ministers met in Jinghong, China, for the first time last November.
The Hainan conference is considerably more comprehensive in scope, since the leaders can table any issues of concern.
Discussions at the Hainan session tomorrow will range wide, covering political matters, economic development, security, the environment and culture.
In fact the agenda sounds so broad that it might curtail talk about serious problems in the river basin.
Along with drought, there is the fact that China and Laos want to keep building dams, further stemming the river's flow.
More than 40 projects are listed under a so-called "Early Harvest" scheme, by which individual countries could begin utilising a monitoring system at the Mekong Mainstream and Information Centre.
Such technical matters should not distract Prime Minister Prayut from his duty in representing Thailand - midstream along the Mekong- and urging China to fully open up about its intentions in controlling an invaluable water resource upon which tens of millions of non-Chinese people depend.
* The Nation is a member of The Straits Times media partner Asia News Network, an alliance of 22 newspapers.