干旱区生态环境知识资源中心

Yellow River source region is located in the hinterland of Qinghai-Tibet Plateau, it is the import source area of the Yellow River because of plenty of water systems. The runoff of the source region occupies 38% of the total source of the whole basin, it plays a decisive role in the security of water supply and environment. In recent years, the runoff decreased obviously in the source region of the Yellow River, the value of runoff was 21.6 x 10(9) m(3) in 1960s, 17.2 x 10 m(3) in the last 10 years. On the basis of the research on the runoff and its temporal and spatial distribution and change characteristics, the change and the cause of the runoff was analyzed from temperature, precipitation, vegetation condition and other natural factors and human activities impact, so as to provide the necessary technology in support of water conservation and ecological protection in the source region of the Yellow River. The results showed that: the runoff variation was mainly influenced by the precipitation. At the same time, temperature rise, permafrost layer thinning and even disappeared, making soil water seep to the deep soil, also led to the runoff decrease. Vegetation degradation and desertification, rainfall infiltration increase, and soil evaporation ability improvement, also led to runoff decrease. Lakes, marshes and other wetlands atrophy, increasing the early loss of precipitation in value, made the runoff function decline too.