One-dimensional morphodynamic model for a tail reach of the Yellow River estuary

Abstract

A one-dimensional morpho-dynamic model was improved to study the unsteady flow and sediment transport processes in a tail reach of the Yellow River Estuary (YRE). In this model, the modified equations for flow hydrodynamics take the effects of sediment concentration and bed evolution into consideration. The improved model was validated using the 2003 and 2015 measurements in the tail reach of the YRE, showing an excellent model data fit of discharge, water level, suspended sediment concentration and cumulative volume of channel evolution. Furthermore, the effect of different cross-sectional spacings was also studied on the model results in the tail reach, with various numerical tests of the 2015 flood event being conducted. It is found that an appropriate cross-sectional distance of less than 3.14 km should be adopted when simulating the process of bed deformation. Moreover, the process of interaction of runoff and tide in 2015 was studied on the basis of the simulated water levels, and the empirical relation of location of tidal limit was established. The results show that the tidal limit in 2015 was 15.84 km downstream of Xihekou.