A Numerical Model for Salinity Intrusion Measurement and Control Based on MacCormack Finite Difference Method and Cubic Spline Interpolation

The purpose of this research was to develop a numerical model of one-dimensional advection-diffusion equation for estimating salinity level in Lower Chao Phraya River, Thailand. The main numerical technique was MacCormack finite-difference scheme with initial and boundary conditions approximated by cubic spline interpolation. The estimates matched satisfactorily with actual measurement data from several salinity monitoring stations along the river. The final model was first used by Thailand’s Metropolitan Waterworks Authority for planning salinity control in 2018.