The Stimson Center in Washington DC has maintained a long and important interest in the future of the Mekong River and, in particular, on hydropower developments associated with the river. Its publications on this topic have always been worth reading. The latest, Letters from the Mekong: Time for New Narrative on Mekong Hydropower, is particularly worthy of attention as it offers a more optimistic view of the future than has been reflected in my own, and indeed others', assessments of the likely future of the river.

An attempt to summarise a 37-page paper in a single post risks being both unfair to its authors and providing insufficient space to some highly contestable conclusions. So the following focuses on, in my judgment, the key issues over which there is ground for debate and disagreement:

  1. That the planned and already undertaken alterations to the design of the Xayaburi dam in Laos, now under construction, will substantially mitigate the barriers to fish migration through the dam.
  2. That in the case of the planned Don Sahong dam in southern Laos, where preliminary work has already begun on the work site but not on the dam itself,  there is reason to believe that there are an additional two channels through which fish can migrate over the Khone Falls rather than the one channel that has been identified previously and on which the dam is projected to be built.
  3. That increased civil society action and an awareness on the part of Mekong countries, particularly Laos, is likely to lead to greater oversight of future hydropower developments on the river, including at Pak Beng (the subject of my post of 2 October) but perhaps not the Lower Se San 2 dam in Cambodia, where construction is continuing. The argument of the Stimson paper here is that future dam projects may not proceed because of civil society opposition. But the dangers of the Lower Se San 2 dam are very considerable indeed. So, even if there is a restriction on the construction of future dams the most concerning horse has already bolted.

These are important judgments and to question them in detail would require considerable space.

In relation to the first point concerning Xayaburi, it will not be until the dam is completed, probably in 2019, that the validity of Stimson's optimism will be tested. Meanwhile, the available research published in Catch and Culture by the Fisheries Division of the Mekong River Commission in 2008 and later in Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin is highly sceptical of the possibility of mitigation along the lines described by the Stimson Paper.

On the second point, even more than is the case in relation to Xayaburi, the proof of the fish pie will be in its eating. We simply will not know whether the assessment the Stimson paper records will be sustained until the dam is built. All that can be said for the moment is that the overwhelming majority of scientific analysis (beginning with this and this) offers a contrary view.

As for the possibility that the Lao and Cambodian governments will change their attitudes, we shall have to wait to see, but it is worth noting that highly regarded research in relation to the Lower Se San 2 dam paints a disturbing picture: a dam on this tributary could alone lead to a diminution of fish stocks in the Mekong River of more than 9% of current catches.

In fairness to Stimson, I must record the paper's own observation that 'The changes to Xayaburi and research results from Don Sahong are a positive step forward--but they do not mask the fact that major obstacles and concerns remain around both projects.' And more generally, picking up on the 'domino effect' to which I have referred on various occasions (that is, the concern that once one or more dams are built this will encourage the building of additional dams): 'The "domino narrative" , may still occur even in the face of rising political, financial , and diplomatic risks'.

I should also acknowledge the authors' kindness in referring to my own work in relation to the Mekong's future.

Photo by Flickr user Timothy Neesam.