Dams on Mekong Tributaries Produce Same Power With Less Impact Than Those on the Main River

mekong river in laos photo
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We've covered plans to put hydropower dams on the Mekong River a couple of times, and in every instance the story is the same: The potential negative effect on the environment (including the human environment, considering the number of people dependent on the river) is huge. A new study by WWF shows however that by changing the location of proposed dams, moving them from the main channel of the river to tributaries, could produce the same amount of electricity, without the negative consequences. Highlighted in the study is a proposed dam in northern Laos, the Xayaburi dam. As proposed it would have a capacity of 1260 MW, while reducing the river basin's connectivity to the region's different ecosystems by 5%. In contrast, two other dams in Laos on tributaries of the Mekong produce 1070 MW and 1540 MW, while having a much lower regional impact--reducing connectivity by 0.8% and 1.2% respectively.

The importance of ecosystem connectivity:

Ecosystem connectivity is critical to maintain the river and its reproductive processes. The study shows graphically that the 50 larger dams located on tributaries already cause serious interruptions to relevant river processes. In the new study, which quantifies the fragmentation by cumulative dam development on the Mekong river system by WWF scientists, "ecosystem connectivity" was measured by the overlap of those ecosystem processes vital to river functioning under an array of conditions such as land cover, hydrology and seasonal factors.