| Popis: |
Southeast Asia’s 3S river basin, which comprises the Sesan, Srepok and Sekong rivers, is an important tributary basin of the Mekong River. The 3S rivers rise in Lao PDR and Vietnam, and flow through Cambodia, where they join before discharging to the Mekong. Vietnam has the highest forest loss and the most (46) dams. Lao PDR retains much of its forest, however, 15 hydropower dams are either being built or licensed for construction in its portion of the Sekong river basin. Cambodia is planning multiple dams on each of the three rivers’ lower reaches. Cambodia’s dams will have the greatest impact on system connectivity and thus the 3S’s important migratory fishery. The flow regime of all three rivers has been altered as dam operations have increased dry season flow and reduced wet season flow. Increased Total Suspended Solids, Nitrate\Nitrite and Total Phosphorous have been observed in the Srepok River in Vietnam, whist there has been little change elsewhere. The three countries are at different stages of developing their national water governance frameworks, with Lao PDR the least developed. A range of climate and development scenarios have been generated for the 3S region. The 3S is highly vulnerable to climate change due to projected increases in temperature and the frequency of extreme floods and droughts. As the transboundary impacts of development in the 3S become clearer, so too does the need for cooperative management of the 3S basin and its water resources, to ensure a sustainable future as the climate changes. |
