TO GO WITH STORY BY JENNY VAUGHAN This p

TO GO WITH STORY BY JENNY VAUGHAN This photo taken on May 22, 2012, shows workers near the entrance of an underground tunnel at the controversial Gibe III dam under construction in Ethiopia’s Omo valley. The Gibe III dam is set to be completed by 2013 and will be Africa’s tallest at 243 metres high. The government says the Gibe III dam will boost development, give access to power for many Ethiopians -- about half of the population -- currently living without it, and generate revenue from the export of electricity to the region. But critics say Ethiopia must also consider the environmental and social impact it will have on some 500,000 people living downstream and at Lake Turkana in neighbouring Kenya, who rely on the river for their livelihood. AFP PHOTO / JENNY VAUGHAN (Photo credit should read JENNY VAUGHAN/AFP/GettyImages)