The Study on the Sustainable Development and Management of the Mekong River, including Impacts of Mainstream Hydropower Projects—known as the Council Study— was conducted by the Mekong River Commission (MRC). Initiated in 2012, the final report was released in 2018. The study’s overall aim is to advise member countries—Cambodia, Lao PDR, Thailand, and Vietnam—on the positive and negative impacts of water resources development in the Lower Mekong Basin, including the plans for extensive hydropower construction. The Council Study’s findings raise serious concerns about the impacts of planned hydropower construction throughout the basin and the trade-offs to food security and the well-being of local populations.
This factsheet summarizes key findings and recommendations of the Council Study in relation to hydropower development in the Lower Mekong Basin. The findings of the Council Study clearly show that the plans for 11 large hydropower dams on the Mekong River’s lower mainstream and 120 tributary dams by 2040 seriously threaten the region’s ecology and economy, as well as local people’s access to sufficient and nutritious food.
Current hydropower plans would reduce the amount of sediment reaching the Mekong Delta by up to 97 percent. Sediment enriches and replenishes the entire basin and supports agriculture, fisheries, and water quality, in turn supporting the economies of Lower Mekong Basin countries. Planned hydropower construction will also cause fish stocks to decline dramatically. The total fishery biomass will be reduced by 35–40% by 2020, and 40–80% by 2040. Combined with the impacts of climate change, the study predicts that the loss of fish may cause ”acute levels of food insecurity in communities in Lao PDR and Cambodia.”
Given these findings, the factsheet poses the question: why are environmentally and socially destructive hydropower projects, such as those on the lower Mekong mainstream, still moving forward? Other options to meet regional energy needs exist. A major recommendation of the Council Study is for MRC member countries to consider emerging energy technologies, such as solar and wind, as alternatives to hydropower. Assessing these alternatives, together with demand-side management and energy-efficiency measures, would provide major insights for managing water, energy, and food security in the lower Mekong basin.