Influence of Floods to the Channel Scour and Fill of Inner Mongolia Reach of the Yellow River

The paper analyzes the characteristics of floods with different discharge and different sediment concentration during flood season at Inner Mongolia reach of the Yellow River and approaches to the influence of floods with different discharge to the channel scour and fill.The outcomes show that a) in the period of 1958 to 2006,the maximum peak discharge at Bayangaole Station is the trend of reducing and the number of days of flood and events of floods with different discharge also show the trend of reducing.In the period of 1987 to 2006,the number of days of flood with different discharge has changed.The proportion of smaller discharge floods is increased and greater discharge floods decreased;b) during the flood period of 1958 to 2006 of Bayangaole Station,the sediment is the trend of reduction.The proportion of smaller discharge flow is the maximum and greater discharge flow the minimum after 1987;c) the coefficient of incoming sediment for the floods with different discharge in a same year is close and the coefficient of incoming sediment for the floods with various discharge increases after 1987;d) the scour and fill of unit water of floods with various discharge increases along with the increase of sediment concentration;e) the critical sediment concentration of channel scour and fill in the floods smaller than 1 000,1 000 to 1 500,1 500 to 2,000,2 000 to 3 000 m3/s and greater than 3,000 m3/s is 5.0,6.0,8.5,10.0 kg/m3 and 6.0 kg/m3 respectively.