Hydropower - ecological threat to Mekong

This is the statement given at the workshop "The impact of hydroelectric dams on ecosystems of river, delta plain and the migration of fish" held by the coordination of the ...

This is the statement given at the workshop "The impact of hydroelectric dams on ecosystems of river, delta plain and the migration of fish" held by the coordination of the World Wide Fund for Nature (WWF), Vietnam Rivers Network (VRN) and Green Innovation and Development Centre (GreenID) in two days 12 - 13/3 in Ho Chi Minh City.

In assessment on the impact of the dam to the river's geomorphology, Prof. Jean Paul Bravard (University of Lyon, France) said the river is a sediment transport chain from upstream to downstream, in which the upstream reservoirs retain water causing bottom sediment which turns downstream water to which called "silt hunger". Its consequence triggers riverbed erosion, negatively impacting on the stability of the delta plain as well as riverine ecosystems and agricultural production.

MeKong river

Prof. Bravard recommended 12 large hydroelectric dams being proposed to set up on the Mekong mainstream should be concerned in regarding the issue of sediment transport through the dam.

When keep discussing the negative impacts of dams to fish migration flows, Prof. Paolo dos Satntos Pompeu (Federal University of Lavras, Brazil) and Dr. John Williams (biology researcher, USA) also said that at present most of the hydropower projects in the Mekong mainstream are designed without migratory route for fish.

The countries in the region haven’t had any research on migratory behavior of fishes so few constructions designed with fish migration routes have failed.

The construction of the high dam would create a wall blocking fish migration to upstream for spawning, so the turbine as well as a gush of water is the culprit which killed fries moving from upstream to downstream for food.

If no effective methods to this problem are created, nearly 1000 species of fish in the Mekong will be at risk of severe decline which affects fishery production throughout the basin - emphasized two delegates.