Hydropower Plant in Laos

Context

The "Nam Theun II" hydropower project (NT2) is a hydroelectric dam on the Nam Theun River in Laos, which has been under construction for more than a decade (since 2005), but recently started commercial operation (in April 2010). The scheme will divert water from the Nam Theun (a Mekong tributary) to Xe Bang Fai (another tributary joining the Mekong 200 km downstream), enabling a generation capacity of 1070MW from a 350m elevation difference between reservoir and power station. NT2 is an industrial and development investment owned by private shareholders and the Laos government, backed by commercial lenders and international financial institutions including the World Bank, the Asian Development Bank and EIB. The Project reservoir has inundated 40% of the Nakai Plateau by creating a shallow reservoir (7m average depth) with a surface area of 450km2 at full supply level. This will reduce in size to a surface area of a little as 70km2 at the end of the dry season. The reservoir has been formed by construction of a high gravity dam, 13 small earthwork saddle dams as well as a spillway and stilling basin especially designed for reservoir level control. A number of environmental impacts were identified and mitigation measures defined. Amongst those a 28000ha offset reforestation project in Khamkeut district and, on the Nakai Plateau, a protected forest area belonging to the Village Forest Association that has the exclusive rights to manage and use the forestry resources.

EO Contribution

The purpose of the EOEuropa project is to assess the progress in the offset reforestation areas and the protected zones regarding land cover and land use (considered periods: 2003/04, 2008/09 and 2011), with particular focus on illegal activities (illegal logging, slash and burn, illegal settlements). Monitoring of the reservoir dynamics (extent) and flood frequency will also be undertaken, with suitable temporal sampling (2008-2011 using both optical and radar data). The information derived from EO will be made available for the watershed management program that is embedded in the NT2 project.