Investigation and Evaluation of Water Resources Quantity in the Yellow River Basin

The precipitation and evaporation in 1956-2000 in the Yellow River Basin were analyzed,then natural river runoff and divisional water resources were calculated and evaluated.The results show that natural runoff is 53.48 billion m3 and water resources in all districts were 71.94 billion m3 in this period.The features of water resources are less water and more sediment,different sources of water and silt,discord of water-silt relation,great variations between years,centralized distribution in a year,long continuous lower flow,and inconsistent distribution of water and soil sources exist in the Yellow River Basin.