Fully Coupled Simulation for Surface Water Flow and Solute Transport in Basin Fertigation

Abstract

Full implicit solutions are constructed for all terms of the Saint–Venant equations and advection–dispersion equation. Thereafter, a global coefficient matrix for forming algebraic equations is established to realize the simultaneous solution of both surface water flow and solute transport equations and a full-coupled model between the surface water flow and solute transport is constructed for basin fertigation. This model completely eliminates splitting errors, which exist in common solutions for both of the aforementioned equations. Moreover, the proposed model can take any time steps and is no longer constrained by stability conditions, such as the CFL (Courant, Friedrichs and Lewy) number and Peclet number. These advantages of the full-coupled model obviously improve the computational efficiency and accuracy, and its applicability in practical simulations. Three basin fertigation experiments are conducted to validate the performance of the proposed full-coupled model. The results show that the developed model achieves good fit between the simulated and observed results, and presents more efficiency than the existing model.