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

Mark R. Bezuijen, Richard Zanre and Marc Goichot, World Wildlife Fund
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.
More information: