There is a lot of controversy and politics involved with the Xayaburi dam in Laos. This first huge dam on the lower Mekong has tracked attention worldwide. While the Lao government sees itself as the manager of the ASEAN battery, NGOs like International Rivers predicting something like the end of the Mekong. The Mekong River Commission, once installed to solve disputes between the Mekong countries (and providing studies and research) shows itself as a toothless Tiger.
The early "No" from Vietnam also showed that ASEAN consensus has it limits - recently Vietnam stepped back and will not veto the dam anymore, although asking Laos to be careful with more projects on the Mekong. Thailand turned silent since it is the investor and will benefit from the electricity purchases. Cambodia says "No", but doesn't make it to a very important bilateral issue.
And then there is the outcry from the international environmental community, mainly NGOs and environmental agencies. The concern is that the dam will effect the life of people downstream, that the fish population can't migrate anymore, and that people have to move from land they were living on for decades.
So some new studies were made especially to improve the damn for the migration of the fish population and regarding the impact of the sediment flow of the river.
The problem I see so far is that it's A against B. Non of the parties is actually looking for consensus. It's clear, Laos needs some income from something. I'm not sure if rubber plantations and mining will be the future and will not do any harm to the environment. Actually I think it's vice versa.
It would have to be a way better idea if the parties have been sitting together and try to get a compromise and a solution that works for both of them instead of just fighting and keeping their own grounds. Anyway construction now has started and below are some impressions from the dam site.