Essence and indicators of the healthy Yellow River

On the basis of the definition of healthy river,the essence of river's life and health standards of river are discussed from the viewpoints of natural and social properties of rivers.The health of a river is regarded as the appraisal of its life and the assessment of its current situation.A healthy river must be a river with equilibrium of natural function and social function.It is suggested that the existence of continuous runoff,expedite and safe channel for water and sediment transport,high quality water,well cycling ecosystem and having a certain water supply capacity should be the major indexes for describing the health of the Yellow River.The hydrologic data from 1956 to 2004 are used to analyze the threshold of the relevant indexes including the minimum flow,maximum flood discharging capacity,bank-full discharge,water quality,wetland area,aquatic life and capacity of water supply.