The Bakhtiari Dam is an arch dam currently under construction on the Bakhtiari River within the Zagros Mountains on the border of Lorestan and Khuzestan Provinces, Iran. At a planned height of , it will be the world's tallest dam once completed and withhold the second largest reservoir in Iran after the Karkheh reservoir. The main purpose of the dam is hydroelectric power production and it will support a 1,500 MW power station. By trapping sediment, the dam is also expected to extend the life of the Dez Dam downstream.