A coupled hydrodynamic numerical model for bay-river network

In order to improve the computational stability and accuracy,the Preissmann's four point implicit difference scheme is used in a 1-D model,and the improved Double Sweep Implicit method is presented in a 2-D model by using the Eulerian Lagrangian method instead of upwind finite difference.An junction control method for water level is established in the 1-D model.The 1-D model is joined together with a 2-D model at the river mouth,which avoids the requirement of the grid over lapping at river segment.The downstream boundary of the 1-D model is the up boundary of the 2-D model.Using the interface section method for transferring hydraulic factors,a new coupled numerical model is established.Application of the coupled model to the Pearl River Delta is carried out for the calculation of the water level,discharge and velocities.Results of the tem poral and spatial distribution of the water level,discharge and velocities coincide with the measure data quite well.