# Mathematical Model for Salinity Intrusion Measurement of Chanthaburi River

## Authors

• Kamonpad Mansilp Department of Integrated Engineering, Establishment Project Faculty of Integrated Engineering and Technology Chanthaburi campus, Rajamangala University of Technology Tawan-Ok, Chanthaburi
• Nopparat Pochai Department of Mathematics, Faculty of Science, King Mongkut's Institute of Technology Ladkrabang

## Keywords:

Mathematical Model, Salinity Intrusion, Advection Diffusion Equation

## Abstract

The purpose of this research was to study a mathematical model of saltwater intrusion into the Chanthaburi River using one-dimensional diffusion and convection equations as governing equations for the problem. The MacCormack numerical method was used to solve mathematical model governing equations to predict water salinity in the estuary and along the Chanthaburi River's course. By collecting sample data at the observation stations and salinity data at the mouth of the Chanthaburi River, the approximated values were calculated using the method of cubic spline interpolation to provide boundary and initial values for the mathematical model. The comparison graphs and data tables of the salinity obtained from each observation station were presented. In addition, data collection with different data frequencies was analyzed. It was found that the cost of data collection for predicting water salinity can be reduced by an acceptable percentage compared to the actual data collected.

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