Simulation of Salinity Intrusion in Chao Phraya River by a Developed Mathematical Model and MacCormack Scheme with Cubic Spline Interpolation

The purpose of this research was to develop a mathematical model for controlling salinity intrusion in Chao Phraya River, Thailand, using one-dimensional advection-diffusion equation. There have been many research studies that applied a mathematical model called dispersion model to estimating salinity concentration. Our proposed dispersion model is simple, using very few parameters, but can simulate salinity intrusion adequately. We used MacCormack scheme to approximate salinity intrusion and cubic spline interpolation technique to approximate field data including initial salinity concentrations and the concentrations at the left boundary. The MacCormack scheme and Cubic Spline interpolation technique were quite suitable for approximating real data, and the proposed mathematical model was able to predict salinity intrusion adequately.