Giant dam is messing up water in Africa even before it is filled

As Ethiopia begins diverting 13.5-billion cubic meters of water from the Blue Nile river to its controversial new megadam, residents of Sudan to the south fear a repetition of last year’s devastating drought. The second stage of filling the $4.5-billion reservoir is ratcheting up tensions between Ethiopia and neighbours Sudan and Egypt, who depend on the Nile to support farming and generate power for their economies.