When Laos announced its intention to proceed with the Xayaburi hydropower project on the lower Mekong over the objections of neighbouring countries in the Mekong River Commission (MRC), it was feared that it would set a precedent.
Those fears were realised on Sept 30 when Laos challenged the MRC again and started construction of a second dam in Champasak province near the Lao-Cambodian border with little fanfare. The Don Sahong project hasn't drawn much attention from the public at large, partly due to the murky question of whether it's actually on the main course of the Mekong.
Activists, however, are again up in arms crying foul and raising concerns over impacts to the river's ecosystem.
The MRC says work at Don Sahong began on Friday. If finished, the dam will be built to a height of up to 30m and cut across a section of river about 100m across.
Besides the environmental impact of the dam, the MRC is concerned that by going ahead with the Don Sahong project Laos is directly challenging the rules governing the Mekong put in place by the MRC, which is comprised of Laos, Vietnam, Cambodia and Thailand. It could be argued that Laos had already crossed that bridge with its decision to proceed with the Xayaburi dam without approval from the MRC, but in that case Laos did at least go through the prior consultation process which requires meetings and consultations between member states.
MRC regulations say that if a member country uses water from the main course of the river during the dry season or diverts water from the main course during the rainy season, it must consult with neighbouring Mekong countries first. Laos did submit documents to the MRC on Sept 30 announcing its intention to start construction of the Don Sahong dam, but did not wait for any feedback before it started work.
Laos says it was not required to adhere to MRC regulations as the Don Sahong dam doesn't sit on the main course of the river, a point of contention among conservationists, academics and even the MRC itself.
MRC communications officer Surasak Glahan told participants at a forum organised by the Asean Journalists' Club in Bangkok _ Don Sahong Dam Project, a New Challenge to Water Governance of the Mekong _ that Laos submitted documents to the MRC on the Don Sahong project in a form, rather than a more formal notification process.
It gave little information other than that the project sits on the Hu Sahong channel of the Mekong, which receives only about 5% of the flow of the river.
"Maybe that's why Laos considers that the project will not have significance to other countries in terms of water usage
[and therefore opted for just notification without feedback from the MRC]," Mr Surasak said.
Many of the conservationists and water experts at the forum said such an interpretation was highly questionable.
Chaiyuth Suksri, a Thai member of a working group studying the documents submitted by Laos to prepare the MRC's response, told the forum that the section of the Mekong crossing the Lao-Cambodian border is unique in the sense that it breaks into a total of 17 smaller channels.
Mr Chaiyuth called them "distributary channels" rather than tributaries. The distinction means that each channel should be considered a portion of the main river, and therefore subject to MRC regulations.
However, in the documents submitted by Laos it is argued that because the dam would block only one of 17 channels it is not actually a dam across the Mekong and therefore there was no need to consult with its neighbours about starting construction. Laos did notify the MRC a month in advance, but argues that because the dam was not affecting the main course of the river there was no need to wait for a response from other member states.
Mr Chaiyuth said such differences have led to complications in applying the MRC's rules.
Some environmentalists say they are more wary of the new Don Sahong project than the one at Xayaburi because it is in one of the river's most important transitional ecological zones, where fish species migrate back and forth to breed. As the potential impacts remain unclear, several groups have pressured MRC members to do everything possible to suspend work on the dam.
Mr Chaiyuth agreed that the area where the dam is built is crucial to fisheries and added that the Hu Sahong channel plays a crucial role due to the fact that it is the only channel that has water flowing through it all year round. Laos counters that it has been working on improving the flow of water through two other channels next to Hu Sahong in order to allow fish to migrate, thus reducing the dam's impacts.
Mr Chaiyuth said he is concerned that if the MRC countries cannot come to an agreement the situation may escalate and lead to conflicts. He urged that more forums and discussions be held and opened to all parties to facilitate different views.
MRC communications officer Mr Surasak said MRC member countries have not yet officially called for special meetings on the Don Sahong project, so the secretariat will have to wait for action from the MRC's Joint Committee to act. He added that the secretariat has limited authority and ultimately the decisions on water use lie with the four countries that form the MRC.
The Don Sahong project is a new challenge for the MRC as it has cut short the process for member countries to come together and talk, said Mr Surasak, adding that the impacts are foreseeable and significant. He urged the Lao government to pay heed to calls to suspend the project to avoid irreversibly damaging the Mekong River ecosystem.