Abstract: Based on the data from the Yellow River, by applying the concept of system coupling, this paper deals with the coupling relation between the water and sediment yield sub-system in the upper and middle river basin and the sediment deposition sub system at the lower river reaches. To describe this coupling relation quantitatively, a multi regression model has been setablished to express the relation between the sedimentaton in the lower Yellow River and the water and sediment quantities from the 4 different source areas in the upper and middle river basin, based on the yearly and the flood event data, respectively. The results obtained show that, on the basis of yearly data, given other factors, each ton sediment from the coarser sediment producing area causes a sedimentation of 0.445 ton, but for each ton sediment from the fine sediment producing area, this sedimentation is only 0.154t, meaning that the effect of the former in causing sedimentation is two times higher than the latter. This indicates that the sediments from coarser and finer sediment producing areas have different influence on the sedimentation process in the lower Yellow River.

Key words: coupling relation of fluvial system, sedimentation in the lower Yellow River, multi regression model for sedimentation