At first I thought I would blog about my experiences on the survey trip this past week, but it happened to be quite similar to the last so I won’t bore anyone with a repeat story. Just as a little aside, the title to that blog definitely would not have been “Rolling on the Mekong Part II”, but rather “Sweating on the Mekong” as that basically sums up my entire week.

Instead I thought I would take a minute to write about the construction of the Don Sahong Dam. The population of Mekong River Irrawaddy dolphins ranges from Kratie, Cambodia north to the Laos/ Cambodian border (190 km). The population at the Laos/Cambodian border is completely isolated from the others and currently numbers just six animals. Despite this small number of dolphins, in 2011 approximately 20,000 tourists visited the transboundary pool to view the animals, thus providing a significant income to the local community. The landscape in this area is also beautiful and contains mountains, waterfalls, and a diverse forest ecosystem.

This section of the Mekong River at the Laos/Cambodian border also happens to be the site where the Laos government is planning to construct the Don Sahong Dam. This hydropower dam will create electricity for the people in the surrounding area of Laos, but it will also likely cause the extirpation of the six remaining dolphins in this transboundary pool. Impacts to the dolphins will be encountered both in the construction and operational phase of the dam. Specifically, the use of explosives, drills, jackhammers, etc. for construction could potentially kill the animals which possess sensitive hearing structures. At the very least, the amplified noise could impair their ability to communicate and forage. Additionally, excessive boat traffic during construction poses the threat of boat strikes or negative long-term effects due to cumulative harassment. During the operation phase the dam will likely change the hydrology of the river because a portion of the sediment will be trapped by the dam and periodically flushed out. By altering the complex hydrology of the Mekong River the dam stands to affect fish behavior and also the habitat of the Irrawaddy dolphins. Finally, the dam will likely block the migrations of more than 100 fish species.

The developers have proposed mitigation measures, but they have not been tested for large-scale projects such as this dam. Given the immediate threats to the dolphins as a result of the dam construction combined with the longer-term consequences including habitat degradation and a decline in fish populations the Don Sahong Dam poses an extremely high risk to the remaining animals in this pool.

There is no denying that Laos deserves the right to develop and provide electricity to its citizens, however, steps should be taken to mitigate the risks to the ecosystem. Thus far the mitigation measures suggested in the EIA (Environmental Impact Assessment) have been inadequate, or in addressing certain risks, completely absent. There is actually an alternative project to Don Sahong, the Thako Project, which proposes to divert water from the river over land to generate power. This option would have a much lower risk to the ecosystem and still produce 75% of the electricity that would be created by the Don Sahong Dam.

At this stage the developers are planning to begin construction in the near future, but WWF is advocating for the termination of the project until further studies taken by a third-party agency can better assess both the social and environmental impacts of the project. Hydropower development is increasing in the region and time will tell if this specific project at the Laos/Cambodian border will further the decline of an ecosystem that not only contains a wealth of biodiversity, but provides vital resources for the people who depend on it.

I have obtained most of the information in this post from articles put out by WWF and have included a link to one here in case anyone wants to learn more.

I thought I would also include just one quote from a science brief written by Gerry Ryan, the WWF Technical Advisor in Kratie:

In the long-term, with many proposed infrastructure developments likely to be constructed on the Mekong River, and with the dolphin population already imperiled it may be difficult to easily attribute cause if the population goes extinct. There is no doubt that conservation of the Mekong’s Last dolphins will be difficult, but the attitude implicit in the environmental impact assessment – –that the dolphin population is already vulnerable and therefore should not stand in the way of development – will achieve nothing but to seal their fate.
http://wwf.panda.org/?215471/Dam-threatens-survival-of-Mekong-dolphins

Cambodia Chronicles