NUMERICAL INVERSION, GROUNDWATER, POROUS-MEDIA, Laplace transform, GALERKIN, Complexity and performance of numerical algorithms, porous media, Transform methods (e.g., integral transforms) applied to PDEs, EQUATION, FINITE-ELEMENT METHOD, CONTAMINANT TRANSPORT, numerical examples, algorithm, Other numerical methods (fluid mechanics), Flows in porous media; filtration; seepage, inverse Laplace transform, time-integration, continued fractions, quotient-difference methods, MODEL, efficiency, transport equation, MASS-TRANSPORT, Initial value problems for second-order parabolic equations, Numerical methods for integral transforms, PARAMETER-ESTIMATION, Spectral, collocation and related methods for initial value and initial-boundary value problems involving PDEs, Inverse Laplace transform