Luangprabang hydropower and its downstream accumulative impact on sediment flux

Abstract

With the aim to develop hydropower potential of the Lower Mekong Basin (LMB) and not to cause substantial impacts to natural environment, in 1980s and early 1990s of the 1ast century, the then Interim Mekong Committee had studied a cascade of run-of-river hydropower projects in the Mekong mainstream. In 2008, Hydropower Development Programmed of the Mekong River Committee (MRC) proposed a scenario consisting of 11 run-of-river hydropower projects. Luangprabang hydropower (LHP) is the second cascade in Laos and the tenth cascade from upstream of Lancang- Mekong river. The Environmenta1 Impact Assessment report of LHP was carried out by Vietnam Association for Conservation of Nature and Environment (VACNE). The accumulative impacts of hydropower cascades in mainstream of Lancang-Mekong river to downstream are significant negative in terms of sediment flux in downstream in which, contribution of the LHP is small or may be insignificant. Sediment impounded in LHP reservoir is estimated to be 10.1 tons/year or 17% sediment flow decreasement at Luangprabang Hydrological Station (LHS). The sediment impounded in LHP reservoir decreases about 6.95% total sediment volume flowing into the Mekong delta in Vietnam.