Modelling soil water movement under unsaturated conditions with the Modified Cubic B-Spline Differential Quadrature method

This study focuses on modelling moisture movement in the unsaturated soil zone with the use of the Modified Cubic B-Spline Differential Quadrature method. The numerical solution of the Richards Equation, which is commonly used in the field of hydrogeology for describing soil moisture movement, was investigated. The differential quadrature method was employed to evaluate the spatial derivatives of the equation variables, and the 4th order Runge-Kutta Method was used to march the solution in time. To verify the accuracy of the developed model, three test cases having different boundary conditions were taken into consideration. The retrieved results are seen to be in good agreement with the values provided by the analytical and other available numerical techniques. On account of its simplicity, efficiency and high accuracy, this method can be an appropriate option for the numerical solution of this type of problems.