A nomadic herder walks their yak and sheep on the daily commute from camp to pasture near the source of the Yellow River.Sanjiangyuan - The three rivers headwaters. The Tibetan plateau is the world's third pole, producing fresh water for billions downstream. In China, the future of the nation depends on how this water tower is conserved. Where the Yangtze, Yellow and Mekong rivers begin, Tibetan nomads are moving to protect the land, its wildlife and in the process their ancient culture from melting away in the face of resettlement and urbanisation..