After several decades of hiatus, plans are being actively implemented to construct a series of hydropower dams on the mainstream of the lower Mekong River. Concerns have been raised, particularly about the impact of the dams on the fishery (particularly migratory species), sediment transport and salinity incursion in the delta. Four riparian countries, with different economic and development goals, different social and environmental concerns, and different political systems, share the lower Mekong. The Mekong River Commission is utilizing DRIFT (Downstream Response to Imposed Flow Transformations), and interactive holistic flow modelling system to allow the lower Mekong countries to assess potential development scenarios and their environmental, economic and social impacts as a basis for negotiating trade-offs which can lead to agreements on the future management of the river. DRIFT is a system developed for evaluating environmental flow scenarios, which has been widely used in Africa.