Numerical Experiments on Solute Transport in Ground- water Flow System

This paper proposes groundwater flow simulation models based on explicit finite difference method (FDFLOW) and Galerkin finite element method (FEFLOW) and solute transport simulation models based on Galerkin finite element method (FESOLUTE), random walk method (RWSOLUTE) and modified method of characteristic (MMOCSOLUTE). These coupled flow and transport models are aimed at simulation of solute transport in two-dimensional, transient, unconfined groundwater flow systems. Proposed models are validated for chosen test cases. Sensitivity of model solutions to various flow and transport parameters viz. transmissivity, pumping rate, longitudinal and transverse dispersivity and effective porosity is analyzed. Further best-performing coupled flow and solute transport model amongst the proposed ones using the criteria of numerical oscillations and average global mass balance error is decided. It is found that the best-performing model is FEFLOW-MMOCSOLUTE model whose adequacy is ascertained by applying it to a Mahi Right Bank Canal (MRBC) command area aquifer in Gujarat state of India. Results showed that the computed head and TDS concentration distributions are in close agreement with the available field observations. KeywordsFDFLOW, FEFLOW, FESOLUTE, MMOCSOLUTE and RWSOLUTE models, Numerical stability and mass balance error, Sensitivity of model solutions, MRBC aquifer, Validation of numerical models