Damming the Nile

The mighty waters of the Nile, are under threat from climate change and booming population growth. The world's longest river, flows from Lake Tana in Ethiopia, through Sudan and into Egypt and is vital to all three. But who controls the water? Ethiopia is building a hydro-electric dam on the border with Sudan. Sudan is using more water for irrigation and is planning its own dams. All of which is raising tensions with Egypt, which gets 95% of its water from the river. Alaistair Leithead travels the length of the river to explore what next for the people who depend on the Nile.