Thursday, 26 March, 2009
At 1102 GMT on BBC Radio 4
Peter Greste journeys down the Omo River from Ethiopia's central highlands to Northern Kenya where the lives of nearly half a million of the world's most remote tribes people are threatened by a massive hydro-electricity project.
The tribes, already fighting over increasingly scarce water and land, have warned that the dam could plunge them into an all-out struggle for survival.
BBC Radio 4's Crossing Continents was broadcast on Thursday, 26 March, 2009 at 1102 GMT and repeated on Monday, 30 March, 2009 at 20:30 GMT.
Reporter: Peter Greste
Producer: Mark Savage