Report raises concern over impact of Don Sahong Dam on Irrawaddy Dolphin

By: 
Mark R. Bezuijen, Richard Zanre and Marc Goichot, World Wildlife Fund
Date: 
Saturday, September 1, 2007

This report examines available information on the potential impact of the proposed Don Sahong hydroelectric dam to the Irrawaddy Dolphin.Key messages from the report are:

  • The Mekong River population of Irrawaddy dolphin is listed in the IUCN Red List as "Critically Endangered", the highest form of threat before a population becomes extinct in the wild.
  • The proposed Don Sahong dam would be built <2 km upstream from the third largest group of Irrawaddy dolphins in the Mekong River. This group of 10 individuals represents 14% of the Mekong population
  • This group is the only population of Irrawaddy dolphins in Lao PDR
  • The highest potential impacts of the dam relate to (a) reduced abundance and diversity of fish resources - prey species for dolphins; (b) altered conditions in the transboundary Dolphin Pool, a primary dolphin habitat downstream from the dam site; (c) a decline in the dry-season distribution of dolphins in the Mekong River, from 190 km to 126 km (34%).
  • It is likely that impacts to fish population and habitats in the Dolphin Pool caused by the proposed dam, could not be effectively mitigated.
  • There is a risk that the proposed Don Sahong dam, when added to existing threats, would contribute to the extinction of the Irrawaddy dolphin in Lao PDR
  • The level of the threat calls for a specific component on dolphin survival in the Environmental Impact Assessment of the Don Sahong dam
  • No positive impact to dolphins could be identified at this stage.
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