Impact of Dams on Salinity Intrusion and Agriculture Productivity: Evidence from Mekong River

Dams and hydropower have long been praised by economists as a game-changing boost for development and a valuable source of renewable and clean energy. However, very few studies have looked at the dark side of the vast environmental impact of dams on the river and coastal system. This paper investigates the trans-border impact of dam construction in the upstream countries on freshwater level in the downstream, which in turn has a spatially and seasonally heterogeneous effect on salinity intrusion as well as agriculture productivity in the delta area. To tackle this question, the study exploits a historical record of construction of dams on Mekong River in East Asia, combined with statistics from Vietnamese government on agriculture productivity. Satellite data has also been employed as a proxy for salinity index and vegetation coverage for a distributional effect analysis. The result suggests that dams' reservoir capacity significantly decreases the level of freshwater discharge to the downstream, lowers rice yield and intensifies saltwater intrusion in the delta.