[en] 1 - Description of program or function: GRIDMAKER serves as a preprocessor for finite element models in solving two- and three-dimensional subsurface flow and pollutant transport problems. It is designed to generate three-point triangular or four-point quadrilateral elements for two-dimensional domains and eight-point hexahedron elements for three-dimensional domains. A two-dimensional domain of an aquifer with a variable depth layer is treated as a special case for depth-integrated two-dimensional, finite element subsurface flow models. The program accommodates the need for aquifers with heterogeneous systems by identifying the type of material in each element. 2 - Method of solution - Based on the method of conformal mapping, the generation of interior nodal points within the two-dimensional domain of interest is performed numerically by the boundary integral element method (BIEM). For a three-dimensional domain, the BIEM techniques are applied in the projected horizontal plane, while the vertical coordinate is transformed by a normalized transformation using local layer thickness