Vientiane Times, 8 December 2012
While there is a temptation to talk about dams as if they were all the same, the Xayaboury hydropower project differs significantly from earlier hydropower projects in the region.
Director General of the Department of Energy Policy and Planning, Dr Daovong Phonekeo, made the assertion in response to international media commentary following a screening of the video “Mekong” in Bangkok, Thailand, last week.
Dr Daovong stressed that the Xayaboury dam will be the first run-of-river scheme to be built on the Mekong River and the first in Laos.
In a run-of-river scheme there is no high dam storing enormous amounts of water. Rather, the dam is relatively low. The water is kept within the river’s course and the level is raised only minimally to allow for the passage of ships and fish migration.
As no reservoir is created, the daily flow of water through the dam is used for power generation throughout the year. The river’s hydrology, or seasonal flows, will continue as normal because the same volume of water that flows upstream will flow downstream .
What’s more, Dr Daovong said, the Xayaboury dam has been designed using sound engineering and proven technology to minimise environmental impacts. He said Laos has gone to great lengths to learn from the errors made by others.
For example, fish passage and sediment flushing systems designed for the Xayaboury dam are based on natural river conditions.
“With respect to Xayaboury, we have conducted thorough and detailed studies to improve fish passage in a number of ways and we have incorporated sediment flushing systems and other mitigation measures as well,” Dr Daovong said.
“We have hired international consulting firms whose work is highly regarded in many parts of the world, including western countries with the most advanced hydropower projects. If there were going to be serious negative impacts, these international firms would not recommend we go ahead with the project because it would affect their global reputation.”
Based on recommendations from independent consultants Poyry and Compagnie Nationale du Rhone, the fish ladder has been extended to ensure the maximum number of fish species will be able to pass through the dam.
The project developers hired fish specialists to study fish migration at the project site and design the best system to allow fish to pass up and downstream of the dam.
In addition, the navigation locks will function as a fish lift, an additional fish tunnel will be built and fish-friendly turbines are to be used. Meanwhile a fish hatching station will complement the lift, ladder and tunnel to ensure that any endangered fish species survive.
Sediment transport through the Xayaboury dam has been designed in accordance with recommendations from Compagnie Nationale du Rhone, which has been operating 19 run-of-river hydropower stations on the Rhone River for the last 50 years.
Dr Daovong stressed that Laos has taken seriously its responsibility to comply with the 1995 Mekong River Commission Agreement. In doing so, it has attached great importance to mitigating any potential social and environmental impacts and has worked very hard to address the concerns of neighbouring countries downstream.
Though new to Laos, there are many successful examples of run-of-river, or “low-head” dams, especially in Europe, which leads the world in hydropower technology. The Rheinfelden power plant, 25 km east of Basel, Switzerland, harnesses the power of the Rhine River. The Fredenau hydroplant near Vienna, Austria, is the latest and largest hydropower facility to be built on the Danube River. Both are state-of-the-art and feature effective fish passage facilities.
