Relationship between runoff and sediment discharge in the main channel of Yellow River from 1950 to 2011

Variations of runoff and sediment discharge dependencies were analyzed based on the annual data of runoff and sediment discharge recorded at the main hydrologic stations in the Yellow River. The results show that the runoff and sediment discharge show a significant decreasing trend at main hydrological stations in Yellow River with the exception of the Tangnaihai station. The accumulation amount of sediment reduction is61. 602 × 108t from 2000 to 2011,estimated by runoff-sediment double mass curve of Huayuankou station.There is a positive correlation between runoff and sediment discharge,with the correlation coefficients from0. 512 to 0. 664. The correlation coefficient between runoff and sediment changes obviously in different decades. The runoff between the upper,middle and lower reaches of Yellow River have significantly positive correlation,and the correlation coefficient ranges from 0. 725 to 0. 904. Meanwhile the sediment discharge shows the similar variation characteristics,but the correlation coefficient ranges from 0. 887 to 0. 918. The proportion of runoff and sediment of the upstream to downstream have bigger difference between different decades,and the minimum value appeared during from 2000 to 2009.