Climate change poses a severe challenge to countries in estuarine regions with high population density and economic activity. When it comes to hydrology and global water resources, multidisciplinary study is required to understand the implications of global warming and climate change. Weather and climate modelling is a multidisciplinary effort that includes not just atmospheric science but also applied mathematics and computer science. Numerical modelling is an important aspect of modern science, and many researchers in both the physical and biological sciences employ it when the underlying equations are too hard to solve analytically, for example. It is critical for such scientists to grasp the numerical approaches utilised in the models in order to have trust that the numerical results are loyal to the underpinning equations.