Estimation of Aeolian Sand into the Yellow River from Desert Aggrading River in the Upper Reaches of the Yellow River

Aeolian sand into the Ningxia-Inner Mongolia reach of the Yellow River is redefined on the basis of the summary of previous study findings of the reach, as the Aeolian sand directly blown into the river by wind force from the areas along both banks of the river reach from Xiaheyan to Toudaoguai in main stream of the Ningxia-Inner Mongolia reach. Moreover, methods to indirectly estimate the amount of Aeolian sand into the Yellow River are put forward after analysis of the contribution of the Aeolian sand into the Yellow River to evolution of channel scouring and deposition as well as the form of sediment deposition in the river. After collection and analysis of the data such as water and sediment data and cross-section data measured at the Ningxia-Inner Mongolia reach, among the amount of Aeolian sand calculation methods, one is based on the principle of sediment balance, the other is based on deducting the sediment deposition brought by overbank flood from the sediment deposition on floodplain. Based on comprehensive results of the two methods, the quantities of and variation in the Aeolian sand into the Ningxia-Inner Mongolia reach of the Yellow River since the 1990s are put forward, which indicates a downtrend of the Aeolian sand into the Ningxia-Inner Mongolia reach of the Yellow River since the 1990s, i.e., from approximately 21 million tons in the 1990s to approximately 11 million tons at present, with an annual average approximating 16 million tons.