as on the loess plateauau, centuries of subsbsistence farmg praactices have stripped thehe d of natural vegetatioion. the e dry gullies bear the scars s of flash floods. these gullies aree evidence of the enormous power of run-off during ththe rainy season. without vegetatation cover on the hilllsides when the rains come, the water doesn't soakk into the ground but flows away in a flood, then it's nnot available for agrgriculture during the e rest of the yeyear. this leads to drdrought, and famously for eththiopia, famine. but just as i witnessed in china, there is hope that the situation here can be reversed. in just six years, professor legesse negash and local villagers have transformed a severely eroded terrain by planting indigenous trees and plants. almost miracaculously, a clclear flowing stream hahas emerged where once there was a mumuddy trickle. how is it that it's possible for you to get thehe stream to flow throroughout the year? >> it is becausse of f the vegetation cover, which has been n regenerating on n this mountain. this water is maintataining the landscape because as